Some Deficiencies in Testing Leda Clay

2009 ◽  
pp. 459-459-12
Author(s):  
DF Coates ◽  
GC McRostie
Keyword(s):  
Leda Clay

The Effect of Sampling on the Undrained Soil Properties of a Leda Soil

1971 ◽  
Vol 8 (4) ◽  
pp. 546-557 ◽  
Author(s):  
Gerald P. Raymond ◽  
David L. Townsend ◽  
Miroslav J Lojkasek
Keyword(s):  
Sampling Method ◽  
Sampling Methods ◽  
Axial Stress ◽  
Pressure Coefficient ◽  
Confining Pressure ◽  
Stress Difference ◽  
Consolidation Pressure ◽  
Failure Index ◽  
Confining Pressures ◽  
Leda Clay

The comparison of consolidated undrained triaxial results on sensitive Leda clay sampled by six different sampling methods is presented. The results indicate that the failure index, represented by the axial stress difference as a fraction of the axial failure stress difference against strain plots, are widely different at very low consolidation pressures, but are similar and approximate to the results from block samples as the consolidation pressure is increased. The pore pressure coefficient A appears to be independent of the sampling method and remains remarkably consistent throughout any test (up to failure) except where the confining pressure is very low or above the preconsolidation pressure.Routine commercial sampling methods (including laboratory preparation) using 50-mm diameter samples were found to partially destroy the cementation bonds, causing a decrease in strength at low confining pressures and an unsafe increase in strength at medium confining pressures. This trend is decreased by better sampling.

ANISOTROPIC CONSOLIDATION OF LEDA CLAY

1969 ◽  
Vol 6 (3) ◽  
pp. 271-286 ◽  
Author(s):  
L. K. Walker ◽  
G. P. Raymond
Keyword(s):  
Stress Ratio ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Volumetric Strain ◽  
Soil Mass ◽  
Plastic Strain Increment ◽  
Anisotropic Consolidation ◽  
Leda Clay ◽  
Stress Ratios ◽  
Effective Principal

Under field loading conditions, the consolidation of a clay layer is likely to take place under effective principal stress ratios (σ1′/σ3′), which vary from point to point throughout the soil mass. From a consideration of idealized stress paths, an estimate is made of the effect of stress ratio on rates of volumetric strain and excess pore water pressure dissipation. These predictions are partly supported by data obtained from anisotropic consolidation tests on Leda clay, the major disagreements being due to the significant influence of structural cementation on the rate process.The experimentally observed rates of shear strain have been analyzed in terms of stress-dilatancy concepts. The plastic strain-increment ratio was shown to be a unique function of effective stress ratio, thus confirming the validity of previous work on remoulded clays. A theoretical prediction of this relationship postulated by Burland (1965) did not approximate to the experimental data, due probably to the influence of secondary deformations. The data did, however, show a relationship similar in form to that derived by Walker (1969) for the secondary deformation of remoulded kaolin.

scholarly journals Studies of Sensitivity and Electro-kinetic Potential in Leda Clay

Nature ◽  
1964 ◽  
Vol 204 (4960) ◽  
pp. 808-809 ◽  
Author(s):  
EDWARD PENNER
Keyword(s):  
Leda Clay

On the Role of Chemistry in the Development and Behavior of the Sensitive Marine Clays of Canada and Scandinavia

1975 ◽  
Vol 12 (3) ◽  
pp. 326-335 ◽  
Author(s):  
J. Kenneth Torrance
Keyword(s):  
Short Range ◽  
Great Variability ◽  
Natural State ◽  
Chemical Factors ◽  
Leda Clay ◽  
Precise Relationship ◽  
And Behavior ◽  
Marine Clays ◽  
Porewater Salinity

The Scandinavian and Canadian experiences are reviewed and analyzed in the light of recent experiments involving the effects of added salts on the remolded shear strength and the liquid limits of two Ottawa area clays, both of which had low porewater salinity in their natural state. The response was similar to that observed in the Scandinavian marine clays where the sensitivity decreases as the salinity increases. It is concluded that the similarities relating to the influence of chemical factors are greater than previous interpretations have indicated. The precise relationship between porewater salinity and sensitivity in Leda clay appears to be unique to each sample and a broad geographic relationship should not be expected. Even short range similarities may be obscured by the generally low salinities of the Canadian marine clays and the great variability in other factors, such as texture and degree of cementation, which also affect the sensitivity.

The Mechanics of Landslides in Leda Clay: Reply

1971 ◽  
Vol 8 (1) ◽  
pp. 148-149
Author(s):  
W. J. Eden ◽  
R. J. Mitchell
Keyword(s):  
Leda Clay
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