Surficial Stability of Compacted Clay: Case Study
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VIEW THE REPLYPublication: Journal of Geotechnical Engineering
Volume 120, Issue 11
Abstract
The factor of safety for surficial stability is highly dependent on the effective cohesion. This study shows that even when triaxial tests are performed at effective pressures as low as 13.8 kPa (2.0 psi), the results may still provide effective cohesion intercepts that are too high. The reason is that the compacted sandy clay behaves as an overconsolidated soil, with effective stress paths bending to the right with low to negative A‐values. As demonstrated by this case study of a surficial failure, the calculated factor of safety was 1.33 using the extrapolated value of effective cohesion of 5.3 kPa (110 psf). An unconfined submerged triaxial test resulted in a lower effective strength envelope, which provided a factor of safety of 0.97 for the surficial failure. There are two factors that can increase the surficial stability of a compacted clay slope: aging and root reinforcement. For the surficial failure, the effect of aging was minor and root reinforcement was not a factor in this case, because the roots had not penetrated to a significant depth at the time of failure.
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References
1.
Casagrande, A. (1936). “The determination of the pre‐consolidation load and its practical significance; Discussion D‐34.” Proc., 1st Int. Conf. on Soil Mech. and Found. Engrg., Cambridge, England, Vol. III, 60–64.
2.
Day, R. W., and Axten, G. W. (1989). “Surficial stability of compacted clay slopes.” J. Geotech. Engrg., ASCE, 115(4), 577–580.
3.
Day, R. W. (1992). “Effective cohesion for compacted clay.” J. Geotech. Engrg., ASCE, 118(4), 611–619.
4.
Day, R. W. (1993a). “Expansion potential according to Uniform building code.” J. Geotech. Engrg., ASCE, 119(6), 1067–1071.
5.
Day, R. W. (1993b). “Surficial slope failure: a case study.” J. Perf. Constr. Fac., ASCE, 7(4), 264–269.
6.
Evans, D. A. (1972). Slope stability rep., Slope stability committee, Department of Building and Safety, Los Angeles, Calif.
7.
Hansen, M. J. (1984). “Strategies for classification of landslides.” Slope instability. John Wiley & Sons, New York, N.Y. 1–25.
8.
Lambe, T. W., and Whitman, R. V. (1969). Soil mechanics. John Wiley & Sons, New York, N.Y.
9.
Leonards, G. A., and Ramiah, B. K. (1960). “Time effects in the consolidation of clays.” STP 254, ASTM, Philadelphia, Pa., 116–130.
10.
Maksimovic, M. (1989). “Nonlinear failure envelope for soils.” J. Geotec. Engrg., ASCE, 115(4), 581–586.
11.
Minimum standards for slope stability analysis. (1978). Orange County Dept. of County Engr.‐Fac., Build. and Safety Div., County of Los Angeles, Los Angeles, Calif.
12.
“NAVFAC DM‐7.2.” (1982). Foundations and earth structures. Dept. of the Navy, Naval Fac. Engrg. Command, Alexandria, Va., 7.2–39.
13.
Pradel, D., and Raad, G. (1993). “Effect of permeability on surficial stability of homogeneous slopes.” J. Geotech. Engrg., ASCE, 119(2), 315–332.
14.
Schmertmann, J. H. (1991). “The mechanical aging of soils.” J. Geotech. Engrg., ASCE, 117(9), 1288–1330.
15.
Singh, R. D., and Gardner, W. S. (1991). “Discussion of ‘Surficial stability of compacted clay slopes.’” J. Geotech. Engrg., ASCE, 117(7), 1122–1125.
16.
“Soil and rock, building stones.” (1986). Annual book of ASTM standards, 04.08, ASTM, Philadelphia, Pa., 282–288.
17.
Terzaghi, K., and Peck, R. B. (1967). Soil mechanics in engrg. practice, 2nd Ed. John Wiley & Sons, Inc., New York, N.Y.
18.
Wu, T. H., Randolph, B. W., and Huang, C. (1993). “Stability of shale embankments.” J. Geotech. Engrg., ASCE, 119(1), 127–146.
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Copyright © 1994 American Society of Civil Engineers.
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Received: Mar 8, 1993
Published online: Nov 1, 1994
Published in print: Nov 1994
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