Site Stabilization

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					Geosynthetics for Sediment Control, Erosion                                                                 Pennsylvania 2010
prevention and Stormwater Management.




         Geosynthetic BMPs for Storm Water Management                   Geotextile Basics for Site Stabilization

                             Site Stabilization                  Materials: Polypropylene(PP) or Polyester (PE).
              •Geotextiles and Geogrids for Base Reinforcement
                                                                 Manufacturing:
              •Geotextiles and Geogrids for Slopes and Walls
                                                                 Non-Woven: Needle Punched or Heat Bonded.
              •Cellular Confinement Slopes
              •Cellular C fi
               C ll l Confinement E th Retention
                                t Earth R t ti                   Woven:
                                                                 Monofilaments (separation, filtration and
              •MSE Wire Form Fascia (Green Walls)
                                                                 load distribution applications up to certain
              •Earth Anchors                                     requirement)
              •Geocomposite Drainage Systems
              •Geofoam                                           Multifilament (Load distribution / reinforcement for
                                                                 more demanding applications.




                       Geogrid Basics for Site Stabilization     Soft soil conditions are sometimes unavoidable.

          Materials: Polypropylene(PP), Polyester (PE) or
          High Density Polyethylene (HDPE).

          Manufacturing:
          1. HDPE Plastic grids are punched and
             drawn.

          2. PP and PE grids are woven, some with
             coatings applied after initial weaving
             process.




         Site Stabilization: Geosynthetic Base Reinforcement
        Over the last 15-20 years the use                                                       Geosynthetic Base
         of geosynyhetics has proven to                                                       Reinforcement provides
         significantly reduce the cost of
        under-cutting a sub-standard sub-                                                     cost effective sub-grade
        grade and back-filling with Select
          Borrow for the construction of
                                                                                               improvement for Soft
             Permanent Roadways.                                                                        Soils.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                            Section Four – Site Stabilization 1
Geosynthetics for Sediment Control, Erosion                                                                                                    Pennsylvania 2010
prevention and Stormwater Management.




                                                                                 When Geotextiles and Geogrids are used in Base reinforcement
                                               Geosynthetic Base                   they can dramatically reduce both undercutting and base
                                                Reinforcement is                                                 Slide 18
                                                                                          requirements of roadways and parking lots.
                                            currently used in a wide
                                             diversity of markets all
                                                 over the world.




                NJ Turnpike Secaucus Meadowlands                                          NJ Turnpike Secaucus Meadowlands
         NJ Turnpike Secaucus Meadowlands




          GEO SLPS CCS SP CCS ER MSE ANCHORS GEO BASE GEOFOAM SC EP RO <   HM     GEO SLPS CCS SP CCS ER MSE ANCHORS GEO BASE GEOFOAM SC EP RO <              HM




                NJ Turnpike Secaucus Meadowlands                                                    Reduced Site Disturbance
         NJ Turnpike Secaucus Meadowlands                                              By reducing the undercut excavation, one roll of Geosynthetic
                                                                                       reinforcement can eliminate as many as…
                                                                                       Ten Trucks Required to Remove the Over-Excavated material, and...




                                                                                      Ten Trucks Required to Bring in the stone base.




                                                                                The resulting reduced site disturbance can reduce sediment, dust, non-point
                                                                                and noise pollution.
          GEO SLPS CCS SP CCS ER MSE ANCHORS GEO BASE GEOFOAM SC EP RO <   HM




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                        Section Four – Site Stabilization 2
Geosynthetics for Sediment Control, Erosion                                                                                        Pennsylvania 2010
prevention and Stormwater Management.




                                                                                                               Key Benefits
                  Base Reinforcement Geosynthetics
        Geotextiles and Geogrids are used in separation, stabilization and     •Separation of the aggregate base from the sub-base to
          reinforcement applications over soft soils, which include paved      reduce failure
         and unpaved roads and embankments. Stabilization geotextiles          •Reinforcement of the sub-base to reduce the base thickness
        provide a cost effective means of extending the life of the road or    •Stabilization of embankments over soft soil
              parking lot, and can reduce both undercutting and base           •Mechanically stabilized embankments (MSE)
                                    requirements.
                                                                                                           Key Design Elements
           BMP Applications and / or Concepts Supported
                                                                               •Bearing capacity of sub grade
                     Minimize total disturbed area – Grading                   •Load bearing requirements of surface
                   Minimize soil compaction in disturbed areas                 •Strength of geosynthetic material
                                                                               •Geosynthetic must be adequately overlapped to prevent open
                                                                               areas between pieces




                                                                                         Post construction inspection checklist
          Preconstruction checklist (site walk-through)
                                                                              •Has geosynthetic been installed throughout the designated area
          •Site Grading Plan                                                  •Were base materials installed and compacted (If Required)
          •Has installation area been marked or flagged                       •Was the perimeter trenched and anchored appropriately
          •Is the condition of the sub grade similar to what was              •Were overlaps installed according to specification
          anticipated and adequate to support loads
          •Presence of geosynthetic
                                                                                                           Maintenance checklist
           Presence
          •Presence of installation tools and equipment
          •Presence of base materials
          •Presence of installation instructions                              •Geosynthetic should be covered with stone as quickly after
          •Presence of Manufacturer’s Representative (If Required)            installation as possible. This will eliminate any maintenance
                                                                              issues.




        Geotextiles and Geogrids for MSE Walls and Slopes                                                                           Why MSE?
          Horizontal layers of Geotextile or Geogrid
                                                                              Unreinforced:
         (planer reinforcement) and the interspersed
                                                                              Typically Flatter Than 2:1
           soil form a mechanically stabilized earth
                        (MSE) system.
                                                                                              A                                       B

                                                                                                                                     Reinforced
                                                                                                                                     earth =
                                                                                                                                     additional land
                                                                                                                                     at top of slope.
                                                                              Reinforced:
                                                                              Typically Steeper Than 2:1




                                                                                              A                                      B




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                     Section Four – Site Stabilization 3
Geosynthetics for Sediment Control, Erosion                                                                                                                     Pennsylvania 2010
prevention and Stormwater Management.




                                                                     Why Reinforced                 Geosynthetic BMPs for Storm Water Management
                                                                           Slopes?                                               Geotextiles and
         Unreinforced:
                                                                                                     Site Stabilization Geogrids for Slopes
         Typically Flatter Than 2:1




                         A                                                         B

                                                            Reinforced
                                                            earth =
                                                            additional land
                                                            at bottom of
         Reinforced:                                        slope.

         Typically Steeper Than 2:1

                                                                                                     Planer reinforcement construction can be difficult in terms of compaction,
                                                                                                     erosion prevention and slumping or sliding at the face of the slope or wall.
                         A                                                         B




          Shallow or global slope failures are often triggered by                                   Rock is a typical surface repair method of slumps.
         storm events and can introduce a significant amount of
                   pollutants into storm water run-off.




          Geosynthetic BMPs for Storm Water Management
                                                                                                     When utilized for slope protection applications, a
                                      Site Stabilization                                            Cellular Confinement System is a multi-component,
                                                                                                              engineered system consisting of:
                         Cellular
                                                                  EROSION CONTROL BLANKET
                      Confinement:                                                                   •an appropriately sized geocell (cell area and depth) functioning
                     Slope Protection                                                                as a stable container/form preventing movement of the infill
                                                                                                     material.
          VERTICAL                                                            CREST
           HEIGHT                     CCS                   H                 ANCHORING              •an anchoring system consisting of anchors and tendons.
                                                        V
                                                                                                     •an infill material which is placed in the cell. Infill materials are
                   INFILL                                                                            selected for their aesthetic and engineering characteristics.
                  VARIOUS                                           GEOSYNTHETIC
                                                                     UNDERLAYER                      •a covering layer consisting of a TRM or ECB when topsoil is
                                                                                          DEADMAN
                                                                 TENDON                   ANCHOR     used to product a vegetated slope surface.
                                            RESTRAINT
                                              CLIP
                                                                                                     •seeds and nutrients if the system is vegetated.
                                                        EARTH         EMBANKMENT MATERIAL
                                                        ANCHOR                                       •a underlying geosynthetic separation layer. This layer is not
                             SLOPE ANGLE
                                             ATRA                                                    always required.
                                            ANCHOR


                                                                                                                                                                                    H




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                                         Section Four – Site Stabilization 4
Geosynthetics for Sediment Control, Erosion                                                           Pennsylvania 2010
prevention and Stormwater Management.




         Cellular confinement in-filled with soil and seed for   Vegetated CCS in-filled with soil and seed for
                     surface erosion protection.                         surface erosion protection.




                   8’




            Sometimes shallow slope failures occur, as           Slope is graded with French drains installed…
              opposed to sheet flow surface erosion.




                                                                      French Drains




           CCS panels are spread and prepared at top of              …prepared CCS panels are staged for
                             slope…                                            installation…




Warren Cohn CPESC, CPSWQ - ACF Environmental                                          Section Four – Site Stabilization 5
Geosynthetics for Sediment Control, Erosion                                                        Pennsylvania 2010
prevention and Stormwater Management.




         …earth anchors were installed to provide stability   …CCS is deployed onto slope above geotextile
           of the CCS system from the top of slope…                       separation layer…




          …prepared CCS panels are attached to anchors                 …CCS during soil filling…
                  and installed down slope…




          …Soil-filled CCS hydro-seeded and then covered          …Completed CCS slope application.
               with straw erosion control blankets…




Warren Cohn CPESC, CPSWQ - ACF Environmental                                    Section Four – Site Stabilization 6
Geosynthetics for Sediment Control, Erosion                                                         Pennsylvania 2010
prevention and Stormwater Management.




                Completed CCS slope application.                        Shop ‘n Save, Monroeville, PA




         Rocks falling from the slope face onto the parking    …the distributor, manufacturer and geotechnical
                        lot was the problem…                  engineering team provided engineering support and
                                                                            preliminary drawings…




         …loose rock and soil was removed to prepare the        …palletized, unexpanded CCS was delivered to
                           surface…                                             project site…




Warren Cohn CPESC, CPSWQ - ACF Environmental                                       Section Four – Site Stabilization 7
Geosynthetics for Sediment Control, Erosion                                                        Pennsylvania 2010
prevention and Stormwater Management.




          …apparatus was created to run tendons through    …tendons being installed through pre-cut holes in
                         CCS panels…                                        CCS panels…




           …CCS panels were spread to provide proper       …the clips, which transfer load from the CCS to the
                     spacing for clips…                     tendons, were tied and secured onto tendons…




                                                                                     Plastic Tie




         …prepared CCS panels staged for installation on    …telescopic lift was used for working on slope…
                          slope…




Warren Cohn CPESC, CPSWQ - ACF Environmental                                     Section Four – Site Stabilization 8
Geosynthetics for Sediment Control, Erosion                                                       Pennsylvania 2010
prevention and Stormwater Management.




         …a working ledge was cut for anchor installation…     …heavy duty earth anchors were selected…




              …earth anchors placed for installation…          …anchors were jack hammered into slope…




              …anchors in place ready for CCS panel          …Geotextile fabric was placed first and then CCS
                          installation…                      panels with tendons secured to anchor I-Nuts …



                             Protruding I-Nuts
                               from anchors




Warren Cohn CPESC, CPSWQ - ACF Environmental                                     Section Four – Site Stabilization 9
Geosynthetics for Sediment Control, Erosion                                                     Pennsylvania 2010
prevention and Stormwater Management.




         …CCS panel installation continues across slope…     …a lightweight, free draining soil and sand
                                                              composite was used for in-fill material…




          …soil and sand composite was clam shelled into   …soil and sand composite was clam shelled into
                             place…                                          place…




            …view of partially in-filled CCS on slope…     …erosion control blankets were used to provide
                                                              temporary protection for seeded in-fill…




Warren Cohn CPESC, CPSWQ - ACF Environmental                                 Section Four – Site Stabilization 10
Geosynthetics for Sediment Control, Erosion                                                                                                               Pennsylvania 2010
prevention and Stormwater Management.




                 …one year later slope is stable, secure and                                                     Three years later.
                                 vegetated.




                            I-99 Pyrite Slope Remediation Project                          During construction of I-99 in PA a large slope was
                                                                                           cut into and excavated exposing veins of Pyrite.
         Case Study   Cellular Confinement / Geogrid / GCL – Liner / Erosion               When air and water interacted with the pyrite,
                                             Control                                       acid rock drainage was created that then leached
                                                                                           into local water wells and exceptional values trout
                                                                                           streams.




                                                                                                                                         The cut slopes as well as the
                                                                                                             Pyrite Veins                significant volume of excavated
                                                                                                                                         material used for fill in other parts
                                                                                                                                         of the projects needed remedial
                                                                                              GEO SLPS CCS SP CCS ER MSE ANCHORS         action.
                                                                                                                                       GEO BASE GEOFOAM SC EP RO < HM




        The large cut face slope used a profile of a 40 mil textured HDPE liner between    CCS cellular confinement was delivered to the site in unexpanded panels and a
        two layers of geotextile cushion with the stone filled CCS system placed on top.   work station was set up to prepare the CCS system for placement on the slope.




                                                                                           Prefabricated panels ready for slope




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                                Section Four – Site Stabilization 11
Geosynthetics for Sediment Control, Erosion                                                                                                                 Pennsylvania 2010
prevention and Stormwater Management.



        Based on design life, durability and critical nature of the application, portions of                            Partially filled CCS system.
        the cellular confinement was reinforced with stainless steel cables. Copper stop
        sleeves with washers were utilized to provide proper spacing of the system when it
        was placed on the slope.




        The length, steepness and infill weight of the CCS                                                                      One portion of CCS / Liner / stone fill system
        application required a significant “deadman” tie-                                                                                    slope completed.
        back.


                                                             Excavated deadman trench




            Concrete deadman in place




                                              The CCS system tied back to the deadman




        Another portion of the remediation project used
         a profile of GCL with Geogrid and soil-filled
                         CCS on top.




                                                                                                   p           p                     g ,                       ,
                                                                                               CCS placed on top of the GCL and Geogrid, soil-filled and seeded, covered with
                                                                                                                 an erosion control blanket and vegetated.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                                  Section Four – Site Stabilization 12
Geosynthetics for Sediment Control, Erosion                                                                            Pennsylvania 2010
prevention and Stormwater Management.



         Completed section of GCL / Geogrid / CCS Cellular     Completed section of GCL / Geogrid / CCS Cellular Confinement composite.
                     Confinement composite.




                                                                 In some cases the ability of the CCS to be
                                                             utilized as a flexible concrete form can provide a
                                                               weather proof, low maintenance slope cover.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                               Section Four – Site Stabilization 13
Geosynthetics for Sediment Control, Erosion                                                                   Pennsylvania 2010
prevention and Stormwater Management.




         CCS BMP Applications Supported: CCS Provides:            CCS BMP Applications Supported: CCS Provides:

                                                                    •Protect/utilize natural flow pathways in overall
           •stable vegetated surfaces where the slope angle
                                                                    stormwater planning and design
           exceeds that of the material desired on the surface,
                                                                    •Cluster uses at each site; build on smallest area
           or
                                                                    possible
           •stable concrete covered slope where armor
                                                                    •Minimize total disturbed area - grading
           protection is desired or
                                                                     Mi i i        il        ti in disturbed
                                                                    •Minimize soil compaction i di t b d area
           •other specialized slope coverings where details of
                                                                    •Re-vegetate and re-forest disturbed areas, using
           the problem so dictate.
                                                                    native species
           •CCS slope protection applications can supplement
                                                                    •Outlet control (Level Spreaders)
           the following BMPs:
                                                                    •Wet Ponds / Retention Basins
           •Protect/conserve enhance utilize riparian areas
                                                                    •Detention / Extended Detention




                            Key Design Elements                                    Key Design Elements

          The CCS uses the following elements:                     The CCS uses the following elements:
          •a bottom geosynthetic separation layer, may be:         •Tendons manufactured from: (material must be
              •non-woven geotextile for soil type separation,
                                                                   compatible with infill and long-term loading
              •woven geotextile for reinforcement and soil type
              separation,                                          •polyester
              •geomembrane for impervious barrier.                       •polypropylene
          •an appropriately sized geocell may be:
                                     geocell,                            •polyethylene
              •small, medium or large cell size                          •Kevlar
              •3, 4, 6, 8, 9.5, 12 inch depth
          •an anchoring system, may be:
                                                                   •Cell infill material, may be:
              •anchor stakes of steel, fiber glass or wood
          •straight                                                  •soil for vegetation
                  •J hook                                            •aggregate
                  •with special ends (ATRA)                          •concrete




                                                                     Preconstruction checklist (site walk-through)
                            Key Design Elements
                                                                    Prior to construction, check:
          The CCS uses the following elements:                      •Site grading plan
                                                                    •Presence of CCS materials
          •seeds and nutrients if vegetated,                           •Geotextile under layer if required
             •choose vegetation appropriate for location,              •Geocell materials
             climatic conditions, and application                      •Anchoring materials
                                                                        Anchoring
          •a covering layer in some applications                       •Infill, if other than from site excavations
             •turf reinforcement mat – choose type that is             •Seeds and nutrients if applicable
             appropriate for application                               •Covering materials if applicable
             •erosion control blanket – choose type that is         •Presence of installation tools
             appropriate for application                            •Presence of installation instructions
                                                                    •Presence of qualified manufacturers
                                                                    representative if required




Warren Cohn CPESC, CPSWQ - ACF Environmental                                            Section Four – Site Stabilization 14
Geosynthetics for Sediment Control, Erosion                                                                              Pennsylvania 2010
prevention and Stormwater Management.




           Post construction inspection checklist                                       Typical
           During and after construction, check:                                    Specification for
           •Is slope geometry as specified                                          Retaining Walls
           •Has the under layer been placed
           •Are the geocell sections
               •expanded correctly                                              Definition
                                                                                A structural wall constructed
               •anchored per plan
                                                                                and located to prevent soil
                                   p
               •infilled with the specified infill                              movement
                                                                                movement.
           If concrete infilled, is the appropriate surface treatment applied
           If vegetated, is the appropriate seed and nutrients applied          Purpose
           Is the appropriate TRM or ECB correctly applied                      To retain soil in place and
                                                                                prevent slope failures and
           Maintenance checklist                                                movement of material down
           If cell emptying occurs at isolated locations, determine the         steep slopes.
           potential cause. Make adjustments to the infill material type
           and refill the emptied cells.




                 Geotextiles and Geogrids for Slopes
        The utilization of Geotextiles and Geogrids for localized
             and global slope and wall stabilization is well
        documented, widely used and beyond the general storm
                  water BMP scope of this presentation.




        Cost and aesthetic issues have lead to a significant increase                           Traditional Solution
        in Mechanically Stabilized Earth (MSE) walls, often using…                    Cast-in-Place Reinforced Concrete Wall
           Concrete Masonry
          Units for Fascia, and




                                                              Reinforced
                                                                   ih
                                                                 with
                                                              Geotextile
                                                              or Geogrid




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                             Section Four – Site Stabilization 15
Geosynthetics for Sediment Control, Erosion                                                                                    Pennsylvania 2010
prevention and Stormwater Management.




          Geosynthetic BMPs for Storm Water Management                          The basic concept for implementing a CCS in these
                                                                              “earth retention” applications is to use a solid outer face
                                 Site Stabilization
                                                                              on the panels and offset them back as they are stacked.
          Cellular
          Confinement
          Earth Retention
                                                INFILL   RETAINED
                                                         SOIL



                          150 mm
        CCS SECTION        or 6 in


                                                    GEOTEXTILE
         TOPSOIL INFILL
        WITH VEGETATION




        The resulting exposed outer cell provide the options of a
              Revegetated Geotextile Reinforced 1:1 slope                       Stacked CCS application can be used as a fascia treatment.
           vegetated, living “green” wall which is aesthetically
         pleasing, provides animal habitat, graffiti proof and will
           provide some retention and filtration of stormwater.


                                                                                                                   INFILL   RETAINED
                                                                                                                            SOIL



                                                                                                150 mm
                                                                              CCS SECTION        or 6 in


                                                                                                                       GEOTEXTILE
                                                                               TOPSOIL INFILL
                                                                              WITH VEGETATION




           All other geotechnical issues and construction requirements          The stacked CCS application starts with an engineered base.
        remain the same. The stacked CCS is used in place of the cast-in-
        place concrete or modular block wall as a treatment for the face of
                                 the slope or wall.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                               Section Four – Site Stabilization 16
Geosynthetics for Sediment Control, Erosion                                                                      Pennsylvania 2010
prevention and Stormwater Management.




        The CCS is opened and held in place by spreader forms          Each CCS lift is compacted using standard equipment
        which are turned over and put in place for soil infill. Note                       and methods.
          protection of outer cell for later placement of topsoil.




           Structural infill was placed in the majority of the CCS     The CCS construction sequence continues lift by lift to
                                    system,                                              desired height.




        Top soil was
        used as infill for
        the front CCS
        cells to facilitate
        re-vegetation…




                      …top of completed CCS structure…                 Completed CCS wall during vegetative establishment.
        Top soil and                                  Free Draining
        structural in-fill                            backfill




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                 Section Four – Site Stabilization 17
Geosynthetics for Sediment Control, Erosion                                                             Pennsylvania 2010
prevention and Stormwater Management.




         Completed CCS wall during vegetative establishment.                Completed, vegetated CCS.




                                                               A stacked CCS can also be used as a gravity structure,
                                                               eliminating the need for deeper embedment lengths for
                                                                                planer reinforcement.




               Temporary Retaining Wall - PENNDOT                      CCS is spread and placed on frame.
               Used as Alternative to sheet piling.




                                                                              8 inch perforated CCS




Warren Cohn CPESC, CPSWQ - ACF Environmental                                        Section Four – Site Stabilization 18
Geosynthetics for Sediment Control, Erosion                                                        Pennsylvania 2010
prevention and Stormwater Management.




         Spreader form is turned over during construction
          Geoweb and frame are turned over for                      Granular infill is placed into CCS
             sequence to facilitate placement of infill.
                                      placement onto wall




                    Polyester geogrid reinforcement




           Granular infill is placed into CCS. Note geogrid       Each lift of CCS infill was compacted.
         reinforcement into embankment area behind CCS.




                                  Geogrid




           ACF Environmental - Pittsburgh, PA




              Entire structure was built in 36 Man-hours           Fairfax County Country Club, N VA
                                                              Stream Bank was
                                                                  eroding…




                                                                                           …into golf course
                                                                                           storm water pond




Warren Cohn CPESC, CPSWQ - ACF Environmental                                    Section Four – Site Stabilization 19
Geosynthetics for Sediment Control, Erosion                                                Pennsylvania 2010
prevention and Stormwater Management.




               Bank was rebuilt with stacked CCS…   A spreader frame was used to
                                                           build each lift




          one lift at
           a time




              CCS is shipped in unexpanded panels            CCS is spread out onto frame,…




                 …frame is turned over in place,…         …structural infill is placed into CCS…




Warren Cohn CPESC, CPSWQ - ACF Environmental                            Section Four – Site Stabilization 20
Geosynthetics for Sediment Control, Erosion                                                                                            Pennsylvania 2010
prevention and Stormwater Management.




         …filled panels are then compacted using standard                      …larger CCS panels were used at bottom of wall…
                            equipment…




              …completed CCS earth retention structure.                                            The first of the two separate structures was constructed
                                                                                                  adjacent to an existing roadway and was designed with a
                                                                                                                      slight internal curve.




                                                                                                   After a Drainage pipe was placed behind the green wall
                                                                                                  area (above left), the base and first few layers of Geoweb
                                                                                                                   are constructed (below).




                                                                                       Standard sequence of construction continues.




         Standard sequence of construction: the unexpanded solid face Geoweb
                    deployed with spacer and ready for soil in-fill.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                           Section Four – Site Stabilization 21
Geosynthetics for Sediment Control, Erosion                                                                                                                Pennsylvania 2010
prevention and Stormwater Management.




                           Partially vegetated view from top of wall.                                          View of completed and vegetated wall.




           The base layer of the second application area: the externally curved             Another “lift” of Geoweb structure in place
                          Geoweb retaining structure in place.                                         and being soil filled.



                                                             Standard equipment and
           Polyester Geogrid
                                                            methods are utilized in the
          deployed to provide                                                                                                                A layer of polyester geogrid was
                                                           construction of Geoweb earth
        internal stabilization of                                                                                                             placed with each Geoweb lift.
                                                                retention structures
               structure




                                                                                             Rebar spacers were used to
                                                                                             provide proper spacing and
                                                                                            configuration of the structure


                                                    Solid faced panel expanded and filled
                                                             with compacted soil                This basic construction sequence was repeated until the wall was completed




                      Completed, vegetated Geoweb retaining structure.                                                                 The Geoweb retaining structure
                                                                                                                                        provided a buttress for a small
                                                                                                                                     parking lot adjacent to the building .




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                                 Section Four – Site Stabilization 22
Geosynthetics for Sediment Control, Erosion                                                                  Pennsylvania 2010
prevention and Stormwater Management.




        Stacked CCS gravity structures may also be vegetated.     Placement of the expanded CCS on the spreader frame.
           Installation here begins with an engineered base.
                                                                       1




                 Infill being placed into expanded CCS.            Construction of stacked CCS continues with structural
                                                                                   infill, one lift at a time.




        Construction of stacked CCS continues on the other side            Completed stacked CCS gravity structures.
                            of the waterway.
             1                                                         1




Warren Cohn CPESC, CPSWQ - ACF Environmental                                              Section Four – Site Stabilization 23
Geosynthetics for Sediment Control, Erosion                                                                                                  Pennsylvania 2010
prevention and Stormwater Management.




         Stacked CCS gravity structures vegetated (13 years).                   Stacked CCS gravity structures vegetated (13 years).




         Stacked CCS structures may be engineered into very                     Stacked CCS structures may be engineered into very
                   steep and High applications.                                           steep and High applications.




         A Cellular Confinement System (CCS) in an earth                          BMP Applications and / or concepts supported
         retention application is a multi-component, engineered
         system consisting of:                                                               The CCS is used for wall structures when:

         •a specifically sized geocell (cell area and depth) with a specific    •Vegetated walls are desired,
         color face panel functioning as a stable container creating a          •Remote construction sites make transportation of materials difficult,
         building unit for the wall.                                            •Free-standing walls for dikes, levees, noise barriers, etc. are desired, or
                                                                                •Stable steepened vegetated channels embankments are desired.
         • a drainage system to remove ground water.
                                                                                A Cellular Confinement System used in an earth retention application can
             t h i l i f           t
         •geotechnical reinforcement.                                           supplement the following BMPs presented in chapters four and five of this
                                                                                manual:
         • a structural infill material which is placed in the interior cell.   • Protect/conserve enhance utilize riparian areas
                                                                                • Protect/utilize natural flow pathways in overall stormwater planning and
         •an infill material in the outer cells which will support vegetation   design
         if vegetation is desired.                                              • Minimize total disturbed area - grading
                                                                                • Minimize soil compaction in disturbed area
         •seed and nutrients if the wall face is vegetated.                     • Re-vegetate and re-forest disturbed areas, using native species
         •a geosynthetic separation layer between the in situ soils and         • Wet Ponds / Retention Basins
                                                                                • Detention / Extended Detention
         the wall backfill materials (if Needed).




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                   Section Four – Site Stabilization 24
Geosynthetics for Sediment Control, Erosion                                                                                    Pennsylvania 2010
prevention and Stormwater Management.




                                                                                        Key Design Elements (continued)
                            Key Benefits
         The CCS provides the following benefits:                           An appropriately sized geocell wall section:
                                                                               •small or medium cell size
                                                                               •6, 8, 9.5 inch depth
         •Aesthetically-pleasing, sustainable, stable vegetation earth
                                                                            Drainage material, may be:
         retention.
                                                                               •perforated under drain pipe
         •Ability to support native vegetation.
                                                                               •composite drainage systems
         •Other special earth retention and free-standing walls where
                                                                            Geosynthetic reinforcement layer material, may be:
         details of the problem so dictate.
                                                                               •geogrid
                                                                               •woven geotextile
                             Key Design Elements                            Cell infill materials(s), may be:
         The CCS uses the following elements:                               •soil for vegetation in outer cells
                                                                               •aggregate in interior cells
         A geosynthetic separation layer, may be:
                                                                               •concrete or grout where flow conditions may remove infill
            •non-woven geotextile for soil type separation,
                                                                               material
            •woven geotextile for reinforcement and soil type separation,
                                                                               Seeds and nutrients if the face is vegetated.
            geomembrane for impervious barrier.
                                                                               •choose vegetation appropriate for location, climatic
                                                                               conditions, and application




             Preconstruction checklist (site walk-through)                           Post construction inspection checklist
                                                                            During and after construction, check:
          Prior to construction, check:                                     Is wall geometry as specified
          Site grading plan                                                 Has the separation layer been placed
          Presence of CCS materials                                         Are the geocell sections
             •Geotextile separation layer if required                       •expanded correctly
             •Geocell materials                                             •infilled with the specified infill
             •Drainage system
             •Geosynthetic reinforcement materials
                      y                                                     Has the drainage system been installed correctly.
             •Infill, if other than from site excavations                   A th geosynthetic layers placed at proper intervals and
                                                                            Are the          th ti l       l   d t        i t    l    d
             Seeds and nutrients if applicable                              proper position between the geocell layers.
             Covering materials if applicable                               If vegetated, is the appropriate seed and nutrients applied.
                                                                            Maintenance checklist
          Presence of installation tools
                                                                            If cell emptying occurs at isolated locations, determine the
          Presence of installation instructions
                                                                            potential cause. Make adjustments to the infill material type and
          Presence of qualified manufacturers representative if
                                                                            refill the emptied cells. If vegetation is required, replant using
          required
                                                                            specified plants, seeds and nutrients.




          Geosynthetic Bag Bank Stabilization                                Geosynthetic Bag Bank Stabilization




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                          Section Four – Site Stabilization 25
Geosynthetics for Sediment Control, Erosion                                  Pennsylvania 2010
prevention and Stormwater Management.




          Geosynthetic Bag Bank Stabilization   Geosynthetic Bag Bank Stabilization




          Geosynthetic Bag Bank Stabilization   Geosynthetic Bag Bank Stabilization




               Reinforced Steep Slopes




Warren Cohn CPESC, CPSWQ - ACF Environmental                 Section Four – Site Stabilization 26
Geosynthetics for Sediment Control, Erosion                                    Pennsylvania 2010
prevention and Stormwater Management.




         Geosynthetic BMPs for Storm Water Management
                               Site Stabilization




            MSE Wire
          Form Fascia
          F    F    i




                    Temporary Retaining Wall

                                Separation
                                                    Primary
                                Geotextile
                                                    Geogrid


         Biaxial
         Geogrid                                    Backfill




                    Welded
                   Wire Form




Warren Cohn CPESC, CPSWQ - ACF Environmental                   Section Four – Site Stabilization 27
Geosynthetics for Sediment Control, Erosion                                                            Pennsylvania 2010
prevention and Stormwater Management.




            Welded wire forms and other geosynthetic                This composite approach provides containment…
         components are used at the outer edge of the wall.



        Seeded top soil

                                                    TRM or other
                                                         ll d
                                                       rolled
                                                    geosynthetic.
        Welded Wire Form




               … and re-vegetation for the fill material.




         Compaction of lift continues. Wire mesh form facilitates
                  compaction at the face of the wall.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                          Section Four – Site Stabilization 28
Geosynthetics for Sediment Control, Erosion                    Pennsylvania 2010
prevention and Stormwater Management.




Warren Cohn CPESC, CPSWQ - ACF Environmental   Section Four – Site Stabilization 29
Geosynthetics for Sediment Control, Erosion                                                                                     Pennsylvania 2010
prevention and Stormwater Management.




                Construction sequence continues to top of slope /wall.




        In this application, a block fascia was used where traffic could        There will be a transition period from installation
                                  see the wall…




         …the welded wire / TRM fascia was used where traffic could
                                 not see it.




                                                                           Highway or Structure
                                                          Why Reinforced                                                 Earth Anchors
                                                                Slopes?                                     Over-excavation into existing slopes for
                                                                                                            required embedment length can add
         Unreinforced:                                                                                      significant cost and site disturbance.
         Typically Flatter Than 2:1                                                                         Utilities or land use at top of slope
                                                                                                            can be problematic for planer
                                                                                                            reinforcement applications


                         A                                         B

                                                 Reinforced
                                                 earth =
                                                 additional land                                                   Driving Earth Anchors into
                                                 at bottom of                                                      existing slopes can be an
         Reinforced:                             slope.                                                            versatile and environmentally
                                                                                                                   friendly problem solving
         Typically Steeper Than 2:1                                                                                alternative.



                         A                                         B




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                       Section Four – Site Stabilization 30
Geosynthetics for Sediment Control, Erosion                                                                                     Pennsylvania 2010
prevention and Stormwater Management.




         Geosynthetic BMPs for Storm Water Management                        Planer reinforcement requires embedment lengths 75% of the
                                                                             height of the wall and can be impractical when cutting into the
                                                                                                    slope is required.
               Site
           Stabilization

                Earth
               Anchors
             (Driven Tipping
                  Plate)
                                                                                                            0.75 of height of wall




        Stacked CCS gravity structures generally need less depth that the     Earth anchors provide reinforcement for walls with a minimal
           embedment length of geogrids or geotextiles, reducing the          amount of depth needed behind the fascia. This reduces the
                      footprint needed for the structure.                            footprint needed for the structure dramatically.




                           Less than 0.75 of height of wall                           Significantly Less than 0.75 of height of wall




        A variety of earth anchors with cables                              With a solid rod in the system it provides the
         are used for light duty applications.
                                                                            strength and engineering guidance for more
                                                                               demanding geotechnical applications.




                                                                                                   Anchor Rod                     Nut & Washer
                                                                                                                                  Plate or Eye-
                                                                                                                                    Nut, etc.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                           Section Four – Site Stabilization 31
Geosynthetics for Sediment Control, Erosion                                                              Pennsylvania 2010
prevention and Stormwater Management.




                                                                      1. Thread anchor rod into anchor
          On many anchors, threaded rebar is an option.




              •Survivability of field trauma
              •Flexibility – available up to 50’ lengths
              •Available galvanized, epoxy coated, etc
              •Matches with rebar design protocol




                 2. Insert drive steel into anchor.              3. Position anchor at proper location and angle.
                                                                             PA 322
                                                           Existing
                                                            Slope




                  4. Drive anchor to proper depth.                          5. Remove drive steel.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                          Section Four – Site Stabilization 32
Geosynthetics for Sediment Control, Erosion                                                                                                 Pennsylvania 2010
prevention and Stormwater Management.




        6. Use load locker to proof anchor into load lock position, and
            then connect nut & washer plate or I-hook to end of the
                                  anchor rod.




               Original Slope                                                                     Earth
                                                                                                 Anchors
                                                                                                  The Anchors
                                                                                               pictured here have
                                                                                               working capacities
                                                                                                  up to 10 tons,
                                                                                                ultimate up to 20
                                                                                                  tons (180kN).



                                                   Additional
                                                    Parking




                                                                                               There are a wide variety of options available to tie fascia
           In areas with limited
                                                                                                               into the earth anchors.
          excavation zones, soil                                   Conventional Geosynthetic
                                                                   Planer Reinforcement




             anchors allow for
         reinforced retaining wall
        construction closer to the
               property lines




                                                                                                Earth anchors can be
                                                                                                utilized with little
                                                                                                disturbance or
                                                                                                displacement of soils.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                          Section Four – Site Stabilization 33
Geosynthetics for Sediment Control, Erosion                                                                                                       Pennsylvania 2010
prevention and Stormwater Management.




            Earth anchors can minimize site disturbance when                                                  Prefabricated Drains
             utilized for a number of restoration applications.
                                                                                               Prefabricated drains provide a specific, engineered
                                                                                              response to a particular drainage problem of how to
                                                                                            collect and re-direct water away from a structure or site.
                                                                                             The core offers strength and provides a secure flow channel for
                                                                                                                     collected water.




                                                                                            The filter fabric retains soil particles while allowing water to freely
                                                                                                                   enter the drainage core.




                     Predictable Performance                                                              Benefits vs. Aggregate
                                                                                            Prefabricated Drains collect significantly more water than pipe
            Unlike pipe and stone systems or aggregate, prefabricated                       and/or aggregate systems. Strips drains can collect 50 times
              drains are manufactured to meet specific physical and                         more water, or the same amount of water 50 times faster, than
                              mechanical properties.                                        pipe/aggregate systems.




                                                                                                               =                                =

         Water Flow Rate:           Core Compression:                Filter Fabric:         While replacing up to two foot thickness of stone for drainage
          The volume of the fluid        The maximum                 The mechanical         purposes, prefabricated drains also provide a dramatic reduction
         that passes through the     compressive stress the         separation of soil      in the weight and volume of the drainage media. This reduction
        formed core in a specific       formed core can          particles from the water   can result in significant the cost and environment impact of
             amount of time.        withstand without failure.    that enters the core.
                                                                                            hauling soil from and aggregate to the site for drainage purposed




                   Sheet Drain – Single Sided                                                Sheet Drain – Single Sided Applications
        Designed to collect liquid from                                                     Single Sided Sheet Drains can
        one side, single sided sheet                                                        replace pipe and/or aggregate in
        drains provide the following                                                        the following applications:
        benefits when compared to                                                           •Foundation & Retaining Walls
        traditional pipe and/or                                                             •Bridge Abutments
        aggregate systems:                                                                  •Parking & Plaza Decks
                                                                                            •Planters
         Low
        •Low Installed Cost                                                                  Lagging
                                                                                            •Lagging Walls
        •Easy to Handle                                                                     •Green Roofs
        •High Flow Capacity                                                                 •Synthetic Turf
        •Predictable Performance
        •Reduced Excavation
        •Superior Collection Capacity
        •Enhances Waterproofing
        •Chemical Resistance
        •Strength and Durability
        •Reduced Clogging




Warren Cohn CPESC, CPSWQ - ACF Environmental                                                                                Section Four – Site Stabilization 34
Geosynthetics for Sediment Control, Erosion                                                                 Pennsylvania 2010
prevention and Stormwater Management.




                   Sheet Drain – Double Sided          Sheet Drain Double Sided Applications
        Designed to collect liquid from              Single Sided Sheet Drains can
        both sides, double sided sheet               replace pipe and/or aggregate in the
        drains provide the following                 following applications:
        benefits when compared to                    •Saturated Soil Conditions
        traditional pipe and/or                      •Weeping Slope Faces
        aggregate systems:                           •Underground Spring Conditions
        •Low Installed Cost
         Low                                         •Reinforced Slope Drain
        •Easy to Handle                              •Drainage Behind Retaining Structures
                                                                                                             Stormwater
        •High Flow Capacity                                                                                  From Above
        •Predictable Performance
        •Reduced Excavation
        •Superior Collection Capacity
        •Enhances Waterproofing
        •Chemical Resistance                                                            Double-
        •Strength and Durability                                                      Sided Sheet
        •Reduced Clogging                                                                Drain      Seepage From Below




                                Chimney Drains                Chimney Drains Applications
          Chimney drain is installed
          vertically in applications
          where full wall coverage is
          not practical due to
          protrusions in the wall                    Earth Slope
          surface, such as soil nails.                                      Fabric
                                                                           against
          Chimney drains may also be                                        soil or
                                                                           lagging
          used in select applications
          where full wall coverage is
          not required and/or cost                                 Sheet
                                                                   Drain
          effective.                                               Strip
                                                                   Drain
                                                               Outlet




                       Green Roofs & Planters        Green Roofs & Planters Applications
        Roof Garden System allows many flat
        or gently sloping roofs to be                         Examples of
        transformed into esthetically pleasing,            Planter and Green
        ecologically sound, above ground
        space on new or existing structures.               Roof Applications
        Benefits Include:
         Increases property values
         Provides aesthetic & therapeutic benefits
         Lowers thermal loads on building
         Reduced water runoff
         R d      d    t     ff
         Eligible for LEED™ Rating System
        PREFABRICATED GREEN ROOF
        DRAINS provide advances in
        drainage, aeration, and root barriers to
        make rooftop vegetation a practical
        and attractive alternative to bare roofs.
        In addition to the newer applications
        for green roofs, prefabricated drains
        have been a staple of planters (rooftop
        or otherwise) for decades.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                             Section Four – Site Stabilization 35
Geosynthetics for Sediment Control, Erosion                                                              Pennsylvania 2010
prevention and Stormwater Management.




             Strip Drains                                      Strip Drain Applications
        Strip drains are two-part              •Residential                               Residential
                                               Basements &                                Basement
        gecomposites that allows               Footers
        water entry from both sides.           •Perimeter Drains
        The polymeric core act as a            •Lawn and Grass
        pipe and is manufactured to            •Playgrounds
        compressive strengths that             •Retaining Walls
                                               •Soil Consolidation
        eliminate the need for                 •Trench Drains
                 t b kfill
        aggregate backfill.                    •Highway Edge
                                               Drains
        Strip drain products have the
        potential to collect 50 times
        more water, or collect the
        same amount of water 50
        times faster, than a standard
        perforated pipe over the
        same period of time.                                Highway Edge       Lawn and
                                                               Drains           Grass




            Combination                             Combination Drain Applications
              Drains                           • Commercial
         Prefabricated combination             Foundation Walls
         drains combine popular low-           • Cut-Off Drains
         profile sheet cores with a high-      • Perimeter Drains
         profile core into one product         • Retaining Wall-
         design.                               Commercial
                                               • Structural Walls
         Combination Drains are
         designed to connect to
         standard plastic pipe to
         provide a continuous and
         uninterrupted flow path for                                                                          Under
                                                                                                              Slabs
         collected water. The result is a
         highly cost-effective design
         alternative to costly pipe and
         stone systems.




              Turf Drains                        Turf Drain Applications
        Whether it’s natural or synthetic      •Natural Turf: Strip Drains
        turf, it needs to be dry and           installed vertically.
        drainage is critical to turf           •Synthetic Turf: Strip Drains
        performance. Prefabricated             installed horizontally.
        drains collect and evacuate            •Synthetic Turf: Sheet Drains
        water faster and more efficiently      installed full coverage
        than aggregate systems.                horizontally.

        In most field designs, 4 to 6
        inches of stone would be
        necessary to achieve adequate
        drainage resulting in extra
        excavation and grading costs.
                                                                        Prefabricated drains makes
                                                                     traditional stone drain systems a
                                                                             design of the past.




Warren Cohn CPESC, CPSWQ - ACF Environmental                                   Section Four – Site Stabilization 36
Geosynthetics for Sediment Control, Erosion                                                                Pennsylvania 2010
prevention and Stormwater Management.




                     Wick Drains                                         Geosynthetic BMPs for Storm Water Management
        •Soil consolidation using prefabricated vertical drains can
        reduce settlement time from years to months.
                                                                                      Site Stabilization
        •Most settlement can occur during construction, keeping post-
        settlement construction settlements to a minimum.
        •Vertical drains require a drainage path to receive and               Lightweight Fill
        transport flow to designated areas.
        •Strip drains provide a cost effective alternative to granular
                                                                                 (Geofoam)
        drainage blankets with over ten times the flow capacity of a
        36” granular blanket.




        Compared to soil, Lightweight Fill can reduce weight and
            associated site disturbance and compaction.                          Roadway Widening




          Sound Barriers




                                                                         Slope
                                                                         Stability
                                                                         Remediation




Warren Cohn CPESC, CPSWQ - ACF Environmental                                              Section Four – Site Stabilization 37
Geosynthetics for Sediment Control, Erosion                                                    Pennsylvania 2010
prevention and Stormwater Management.




           Retaining & Foundation Walls                                    Bridge Approach




        Many building and
            t i i      ll
          retaining wall
        projects use foam
          to reduce soil
            pressures




            I-93 Ramp –Central Artery Project             InsulFoam GF - Physical Properties
                  (Big Dig), Boston, MA




            Embankment Construction over Soft Soils              Highway
                                                                Applications




                                                      Over 900 yd³ installed
                                                        per day




Warren Cohn CPESC, CPSWQ - ACF Environmental                                   Section Four – Site Stabilization 38
Geosynthetics for Sediment Control, Erosion                                                   Pennsylvania 2010
prevention and Stormwater Management.




                                                            Woodrow Wilson Bridge, Alexandria, VA
           Bridge Abutment Applications




                                   Geofoam covered
         Geofoam in Place           with geotextile
                                   during backfilling




                            Introduction                              Applications
           "Geofoam"     describes large blocks of
           synthetic material weighing from 0.75 pcf     Transportation: Embankments, Side-hill
                                                         fill, Approach Fill (bridge abutments), General
           to 2 pcf, depending on the physical           fill (roadways, parking, etc.), Median and
           properties required.                          sound barriers
           This extremely light weight fill material
           permits immediate construction over           Architectural: Landscape, Plaza decks,
                                                         Bermed structures
           areas where the soil characteristics
           would normally require months of              Structural:     Structural fill (foundations,
           surcharging or other exotic treatments to     etc.), Earth retaining structures, General Earth
                                                         Works, Flood control levees, Dikes/Berms
           raise it’s strength.




                       Benefits                                Benefits (Continued)
           •Super Lightweight Fill - 1 lb. per          •Various Large Block Sizes
           cu. ft.                                      •No Leachates
           •Predictable Material Behavior               •Inert in Long Term Burial
           • High Strength to Density Ratio             Conditions
           •Manufactured to ASTM                        •Volume Stability
           Standards                                    •Easily Shaped in Field and
           •Termite Resistant Perform                   Plant
           Guard EPS*                                   •Availability




Warren Cohn CPESC, CPSWQ - ACF Environmental                              Section Four – Site Stabilization 39

				
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