Frost heaving pressures in particulate materials

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					                        F R O S T HEAVING PRESSURES IN
                             PARTICULATE MATERIALS

             -                               E. P e n n e r

                            D i v i s i o n of Building R e s e a r c h
                      N a t i o n a l R e s e a r c h C o u n c i l of C a n a d a
                                                 Ottawa

                                            ABSTRACT

       M e a s u r e m e n t s of e q u i l i b r i u m i c e l e n s h e a v i n g p r e s s u r e s i n
c l o s e - p a c k a r r a y s of u n i f o r m s i z e g l a s s b e a d s ( P e n n e r , 1966) i n
r e l a t i o n t o b e a d s i z e a r e i n a g r e e m e n t with t h e t h e o r y of E v e r e t t
and H a y n e s (19 65).           S i m i l a r heaving p r e s s u r e m e a s u r e m e n t s w e r e
d e t e r m i n e d on f r a c t i o n s of f r a g m e n t a l p a r t i c l e s i n t h e s i l t and
f i n e s a n d r a n g e ( P e n n e r , 1967 and 1968). I t i s d e m o n s t r a t e d t h a t
t h e s m a l l e r p a r t i c l e s within a g i v e n r a n g e h a v e a p r e d o m i n a n t
i n f l u e n c e on t h e e q u i l i b r i u m i c e l e n s heaving p r e s s u r e s g e n e r a t e d .
F r o m t h i s i t i s c o n c l u d e d t h a t t h e p r e s e n t c r i t e r i a b a s e d on p a r -
ticles s i z e     --   with l i m i t s on t h e a m o u n t of f i n e s p e r m i t t e d           --   is
a n a c c e p t a b l e a p p r o a c h t o defining t h e f r o s t s u s c e p t i b i l i t y of
e a r t h m a t e r i a l s f o r soil engineering purposes.




       The s m a l l e s t particles in a particulate porous s y s t e m play an
i m p o r t a n t r o l e i n d e t e r m i n i n g t h e m a g n i t u d e of i c e l e n s h e a v i n g
p r e s s u r e s generated.            The supporting theory lends credence to
using p a r t i c l e s i z e a s a v a l i d f r o s t - s u s c e p t i b i l i t y c r i t e r i o n f o r
naturally occurring materials.                          This note reviews in brief the
t h e o r y of i c e l e n s g r o w t h , t h e n a t u r e of f r o s t a c t i o n p r o b l e m s i n
e a r t h s t r u c t u r e s , t h e i m p o r t a n c e of a c c u r a t e l y p r e d i c t i n g t h e f r o s t
s u s c e p t i b i l i t y of e a r t h m a t e r i a l s , t h e e x p e r i m e n t a l m e a s u r e m e n t s
of i c e l e n s heaving p r e s s u r e s i n s i m p l e s y s t e m s t o t e s t t h e t h e o r y ,
and the m e a s u r e d relationship between the i c e lens heaving p r e s s u r e
a n d t h e s i z e of f r a g m e n t a l p a r t i c l e s i n m o r e c o m p l e x p o r o u s s y s t e m s .
         THEORY AND PRACTICE:                             PAST AND P R E S E N T

       Following the d e v e l o p m e n t of the t h e o r y on i c e l e n s growth
under i d e a l i z e d conditions i n p o r o u s m e d i a ( E v e r e t t , 1961), a m o r e
c o m p r e h e n s i v e and g e n e r a l i z e d t r e a t m e n t applying to r e a l p o r o u s
s y s t e m s w a s published f o r p o r e g e o m e t r i e s of g r e a t e r complexity
( E v e r e t t and Haynes, 1965).                T h e s e widely-quoted t h e o r e t i c a l
papers have greatly stimulated f r o s t action r e s e a r c h in recent
y e a r s , l a r g e l y b y providing a sound and convincing t h e o r e t i c a l
basis.      T h e theory, however, was not a c o m p l e t e l y n e w concept,
n o r w a s this c l a i m e d b y the a u t h o r s ( E v e r e t t , 1961; E v e r e t t and
Haynes, 1965). A s p e c t s of the t h e r m o d y n a m i c s of f r e e z i n g p o r o u s
s y s t e m s had b e e n d e a l t with i n s o m e d e t a i l e a r l i e r b y Edlefson
and A n d e r s o n (1943), W i n t e r k o r n (1955), J u m i k i s (1956), P e n n e r
(1957), and Gold (1957).

       E x t e n s i v e l a b o r a t o r y testing of s o i l s f o r f r o s t s u s c e p t i b i l i t y
had b e e n c a r r i e d out m u c h e a r l i e r b y Beskow (1935), T a b e r (1929).
C a s a g r a n d e (1932), and l a t e r b y the U. S. C o r p s of E n g i n e e r s .
T h i s l a s t study, d e s c r i b e d b y Line11 and K a p l a r (1959), provided
w o r k a b l e e m p i r i c a l r e l a t i o n s h i p s between the g r a i n - s i z e c o m p o s i -
tion of s o i l s and f r o s t s u s c e p t i b i l i t y t h a t could b e applied
d i r e c t l y to s o i l engineering p r o b l e m s .

   T H E NEED FOR IMPROVED FROST ACTION PREDICTIONS

       D e s p i t e c h a n g e s i n d e s i g n a p p r o a c h e s , e. g . , the u s e of t h e r -
m a l b a r r i e r s , the need f o r f u r t h e r i m p r o v e m e n t s i n the a s s e s s m e n t
of f r o s t s u s c e p t i b i l i t y f o r e a r t h s t r u c t u r e s h a s b e c o m e even m o r e
critical in recent years.                  T h e d e m a n d f o r h i g h e r quality highways,
r a i l w a y s and a i r p o r t runways is a r e s u l t of the i n c r e a s e d t r a i n
and v e h i c l e s p e e d s and the h i g h e r take-off and landing s p e e d s of
aircraft.        Roads and a i r p o r t s m u s t now h a v e a y e a r - r o u n d c a p a -
b i l i t y t o s u p p o r t l a r g e r l o a d s and l a r g e unheated s t r u c t u r e s          such
a s p a r k i n g g a r a g e s and w a r e h o u s e s       r e q u i r e s t a b l e foundations.
On t h e o t h e r hand, r e a d i l y a v a i l a b l e s o u r c e s of good quality e a r t h
m a t e r i a l s , s u c h a s s a n d s and g r a v e l s , a r e being r a p i d l y depleted
in many regions.               Engineering failures that result f r o m f r o s t
a c t i o n a r e not only e x p e n s i v e to r e p a i r , b u t c a u s e m u c h inconven-
i e n c e when the t e m p o r a r y l o s s i n the u s e of the s t r u c t u r e is a l s o

                                                  3 80
involved.         It i s imperative, therefore, that where freezing i s
p e r m i t t e d , t h e p e r f o r m a n c e of e a r t h m a t e r i a l s t h a t a r e b o r d e r l i n e
with r e s p e c t t o f r o s t s u s c e p t i b i l i t y a r e p r o p e r l y a s s e s s e d s o t h a t
good m a t e r i a l s w i l l n o t b e excluded and p o o r q u a l i t y m a t e r i a l s
will b e r e c o g n i z e d a n d p r o c e s s e d o r r e j e c t e d t o avoid c o s t l y
mistakes.

          BASIS FOR FROST-SUSCEPTIBILITY CRITERIA

       A c o m m o n l y u s e d a p p r o a c h is t o d e t e r m i n e f r o s t s u s c e p t i b i l i t y
e x p e r i m e n t a l l y , o r t o e s t i m a t e i t on t h e b a s i s of h e a v e r a t e .
A c c e p t a n c e o r r e j e c t i o n i s b a s e d on t h e a m o u n t of h e a v e , o v e r a
w i n t e r p e r i o d , t h a t c a n b e t o l e r a t e d without d e t r i m e n t a l e f f e c t s .
Changes i n the riding quality resulting f r o m differential heave
t h a t i s p e r m i t t e d and p o s s i b l y t h e l o s s of s t r e n g t h on thawing,
would b e the l i m i t i n g p e r f o r m a n c e f a c t o r s f o r highways, s t r e e t s
and a i r p o r t r u n w a y s .     T h e a m o u n t of d i f f e r e n t i a l h e a v e t h a t c a n
b e s a f e l y a c c o m m o d a t e d without d a m a g e to t h e foundation and s u p e r -
s t r u c t u r e would b e t h e d e t e r m i n i n g f a c t o r f o r unheated s t r u c t u r e s .

       Heaving p r e s s u r e s t h a t a r e g e n e r a t e d d u r i n g the f r e e z i n g of
e a r t h m a t e r i a l s d u e to t h e i c e - w a t e r p h a s e c h a n g e c a n a l s o b e used
to a s s e s s f r o s t susceptibility.             T h i s c r i t e r i o n h a s n o t found
a c c e p t a n c e i n p r a c t i c e although i t i s d i r e c t l y a p p l i c a b l e t o h e a v -
ing p r o b l e m s involving f o u n d a t i o n s of b u i l d i n g s .

       T h e m e a s u r e m e n t of heaving p r e s s u r e s r e s u l t i n g f r o m i c e l e n s -
ing, h o w e v e r , h a s b e e n m o s t u s e f u l t o t e s t t h e v a l i d i t y of f r o s t
h e a v e t h e o r i e s m a i n l y b e c a u s e the heaving p r e s s u r e i s o n e of t h e
v a r i a b l e s i n t h e r m o d y n a m i c equations t h a t c a n b e m e a s u r e d
experimentally.

                       THEORY O F I C E LENS GROWTH
                T E S T E D WITH UNIFORM GLASS BEADS

       T h e equation b y E v e r e t t and H a y n e s (1965) r e l a t i n g the e q u i -
l i b r i u m i c e l e n s h e a v i n g p r e s s u r e t o t h e r a d i u s of u n i f o r m g l a s s
s p h e r e s i n a c l o s e - p a c k a r r a y w a s t e s t e d ( P e n n e r , 1966). T h e
equation t h a t a p p l i e s t o t h i s p a r t i c u l a r g e o m e t r y i s a s follows:
w h e r e Ap i s t h e heaving p r e s s u r e , r i s t h e r a d i u s of t h e s p h e r e , B'
i s a c o n s t a n t e q u a l t o 5. 6, 0 i s the c o n t a c t a n g l e a n d u .              i s t h e in-
                                                                                             1W
                                                                       H)
w a t e r i n t e r f a c i a l e n e r g y t e r m (35 e r g s ~ m - (~ e s s t e v e d t , 1964).
T h e a g r e e m e n t t h a t w a s shown t o e x i s t b e t w e e n t h i s e q u a t i o n and
t h e m e a s u r e m e n t s c a r r i e d out by t h e a u t h o r f o r two s i z e s of b e a d s ,
1 9 . 4 and 12 m i c r o n s d i a m e t e r , i s b e l i e v e d t o v e r i f y e x p e r i m e n t a l l y
t h e equation.

     HEAVING PRESSURES IN FRAGMENTAL MATERIALS

        T h e l a b o r a t o r y e q u i p m e n t developed f o r t h e e a r l i e r s t u d i e s o n
g l a s s b e a d s w a s a l s o u s e d t o d e t e r m i n e t h e heaving p r e s s u r e i n
s i z e d f r a c t i o n s of f r a g m e n t a l p a r t i c l e s .   Two s t u d i e s h a v e b e e n
published on t h i s a s p e c t by t h e a u t h o r ( P e n n e r , 1967; P e n n e r , 1968).
Elutriation techniques w e r e used i n both c a s e s                           --   p o t t e r 1s f l i n t
and P F R A s i l t       --   to s e p a r a t e the p a r t i c l e s into n a r r o w s i z e ranges.
The particle s i z e s f o r a l l fractions was determined by preparing
s m e a r s of t h e s e p a r a t e s on g l a s s s l i d e s a n d m e a s u r i n g t h e p a r t i c l e
s i z e s on e n l a r g e d m i c r o p h o t o g r a p h s .       The s i z e assigned to each
p a r t i c l e w a s t h e a v e r a g e of t h e l a r g e s t and the s m a l l e s t p a r t i c l e
d i a m e t e r ; i n t h i s way t h e c o m p l e t e s i z e d i s t r i b u t i o n w a s e s t a b -
l i s h e d by m e a s u r i n g s o m e 500 p a r t i c l e s f r o m e a c h s a m p l e .

        T h e a u t h o r 1s s t u d i e s r e f e r r e d t o w e r e f o r s i z e f r a c t i o n s
l a r g e r t h a n c l a y s i z e b e c a u s e t h e s i z e of p a r t i c l e s in t h e c l a y
r a n g e could n o t b e d e t e r m i n e d r e a d i l y with t h e s a m e a c c u r a c y .                 Sedi-
mentation analyses w e r e not considered to b e sufficiently p r e c i s e
to establish the p a r t i c l e s i z e s f o r these studies.                       T h e solid l i n e
i n F i g . 1 i s t h e p l o t of t h e E v e r e t t and Haynes (1965) equation.
The i c e lens p r e s s u r e - d i a m e t e r values f o r the uniform-size glass
b e a d s a r e shown a s open s q u a r e s .                  The solid c i r c l e symbols a r e
t h e r e s u l t s f o r the v a r i o u s f r a c t i o n s of P F R A s i l t .       T h e open
c i r c l e s a r e f o r t h e f r a c t i o n s of p o t t e r s flint.      In e a c h c a s e t h e
m e a s u r e d i c e l e n s heaving p r e s s u r e i s plotted a g a i n s t t h e m e a s u r e d
d i a m e t e r of the s m a l l e s t s i z e p a r t i c l e i n e a c h f r a c t i o n .       The
r a n g e in p a r t i c l e s i z e f o r e a c h f r a c t i o n i s g i v e n on t h e F i g u r e
n e a r t h e plotted point.
       The v a l u e s f a l l both above and below the t h e o r e t i c a l line but
i t i s believed that the m e a s u r e of a g r e e m e n t achieved d r a w s a t t e n -
tion to the p r e d o m i n a n t influence of the s m a l l e s t p a r t i c l e s in
e s t a b l i s h i n g the heaving p r e s s u r e s .     Deviations in the m e a s u r e -
m e n t s f r o m the t h e o r y a r e thought to b e a t t r i b u t a b l e to the f r a g -
m e n t a l n a t u r e of the p a r t i c l e s , v a r i a t i o n s in s a m p l e density,
l o c a l non-homogeneity,            and e r r o r s i n p r e s s u r e m e a s u r e m e n t s .   It
i s believed t h a t a t e q u i l i b r i u m ( s t a t e of non-propagation of i c e )
the i c e l w a t e r boundary positions itself o v e r the m i n i m u m s i z e d
p o r e s and to a c h i e v e t h i s t h e b o u n d a r y m u s t have a n undulating
configuration.



       90


       80   -                                                                                 -

       70                                                                                     -
                                                0 POTTERS F L I N T
                                                 lS O I L     (P.F.R.A.        SILT)

                                                 I
                                                     S P H E R I C A L G L A S S BEADS
                                                     S A M E V A L U E FOR POTTERS
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                                H E A V I N G PRESSURE, k g l c m 2



FIGURE 1           Relation Between Heaving P r e s s u r e
                   And S m a l l e s t P a r t i c l e i n F r a c t i o n
                                        CONCLUSIONS

       T h e r e s u l t s g i v e n in t h i s note s u p p o r t the u s e of p a r t i c l e
s i z e a s a valid property f o r establishing f r o s t susceptibility.
T h e i m p o r t a n c e of t h e s m a l l e r p a r t i c l e s i n a s o i l s y s t e m i s b a s e d
on a t h e o r y t h a t h a s b e e n s u p p o r t e d b y l a b o r a t o r y m e a s u r e m e n t s and
t o which t h e heaving p r e s s u r e s d u e t o i c e l e n s e s i n r e a l p o r o u s
s y s t e m s conform.

       The r e s e a r c h studies indicate that c r i t e r i a used based
                                                                                              m
on g r a i n s i z e could b e i m p r o v e d by i n c r e a s i n g t h e a l l o v ~ a b l e i n i -
m u m s i z e of t h e s m a l l e s t p a r t i c l e s with f u r t h e r l i m i t a t i o n s on the
p e r m i s s i b l e a m o u n t of f i n e s .

                               ACKNOWLEDGEMENTS

       T h i s p a p e r i s a c o n t r i b u t i o n f r o m the Division of Building
R e s e a r c h , National R e s e a r c h Council of Canada, a n d i s published
with the a p p r o v a l of D r . N. B. Hutcheon, D i r e c t o r of t h e Division.

                                         REFERENCES

Beskow, G.            1935.       S o i l f r e e z i n g a n d f r o s t heaving with s p e c i a l
       a p p l i c a t i o n t o r o a d s and r a i l r o a d s .   T r a n s l a t e d by J. 0.
       Osterberg.            Technical Institute, Northwestern University
       1947.

C a s a g r a n d e , A.,     1932.       D i s c u s s i o n on f r o s t heaving.          Highway
       R e s e a r c h B o a r d P r o c . , Vol. 11, P t . 1, p. 168-172.

Edlefson, N. E . and A n d e r s o n , A. B. B . ,                   1943.       T h e r m o d y n a m i c s of
       soil moisture.             H i l g a r d i a , Vol. 15, p. 31-268.

E v e r e t t , D. H . ,    19 61.     T h e t h e r m o d y n a m i c s of f r o s t a c t i o n i n
       porous solids.             T r a n s . F a r a d a y S o c . , Vol. 57, p. 1541-51.

E v e r e t t , D. H. and H a y n e s , J . M . ,           1965.      C a p i l l a r y p r o p e r t i e s of
       s o m e m o d e l p o r e s y s t e m s with r e f e r e n c e to f r o s t d a m a g e .
       R I L E M B u l l . , New S e r i e s , Vol. 27, p. 31-38.
Gold, L. W.,           1957.       A possible f o r c e m e c h a n i s m associated with
       t h e f r e e z i n g of w a t e r i n p o r o u s m a t e r i a l s .     Highway R e s e a r c h
       B o a r d Bull.        No. 168, p. 65-72.

H e s s t v e d t , E., 1964.          The interfacial energy i c e / w a t e r
       N o r w e g i a n G e o t e c h . I n s t . , P u b . 56, 4p.

J u m i k i s , A. R . , 1956.          The soil freezing experiment.                      Highway
       R e s e a r c h B o a r d Bull. No 135, p. 150-165.

L i n e l l , K. A. and C. W. K a p l a r , 1959.                   T h e f a c t o r of s o i l and
       m a t e r i a l type in f r o s t action.            Highway R e s e a r c h B o a r d
       Bull. No. 225, p. 81-128.

P e n n e r , E., 1957.           Soil m o i s t u r e tension and i c e segregation.
       Highway R e s e a r c h B o a r d Bull. NO. 168, p. 50-64.

P e n n e r , E., 19 66.          P r e s s u r e developed during the unidirectional
       f r e e z i n g of w a t e r s a t u r a t e d p o r o u s m a t e r i a l s .   Proc.,
       I n t e r n a t . Conf. on L o w T e m p . S c i e n c e , Vol. 1, p a r t 2,
       p. 1401-1412.

Penner, E.,           19 67.      Heaving p r e s s u r e i n s o i l s d u r i n g u n i d r e c -
       tional freezing.             Can. Geotech. J o u r n a l , Vol IV, No. 4
       p. 398-408.

Penner, E.,           1968.       P a r t i c l e s i z e a s a b a s i s for predicting f r o s t
       action in soils.            S o i l s and F o u n d a t i o n s , Vol. 8, No. 4
       p. 21-29.

T a b e r , S . , 1929.          F r o s t heaving.         J o u r n a l of Geology, Vol. 37,
       No. 1, p. 428-461.

W i n t e r k o r n , H. F . ,    1955.       D i s c u s s i o n of "Suction f o r c e on s o i l s
       upon f r e e z i n g " .     P r o c . , A m e r . S o c . Civ. E n g i n e e r s ,
       Vo1. 81, S e p a r a t e No. 656, p. 6 - 9 .

				
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