ISSN: 0090-3973
Page Count: 9

Stress-State Permeability Relationships for Clays with Coarse Fraction

Pandian, NS
Associate professor, research scholar, and professor,Indian Institute of Science,

Narasimha Raju, PSR
Associate professor, research scholar, and professor,Indian Institute of Science,

Nagaraj, TS
Associate professor, research scholar, and professor,Indian Institute of Science,

(Received 15 April 1996; accepted 9 December 1997)

Abstract

In standard laboratory consolidation tests, only the fraction of soil passing through a particular size of the sieve, called the matrix material, is used. This size is usually restricted to 110 of the height of the consolidation ring. Particles larger than this size that are removed before the test may consist of gravel, fragments of sock, or other coarse materials. Hence, it is not possible to estimate the compressibility and permeability of the total material based on the compressibility and permeability behavior obtained from laboratory consolidation tests on the matrix material. In the present investigation an attempt has been made to estimate the compressibility and permeability behavior of the total material based on the compressibility and permeability behavior of the matrix material. The results indicate that the presence of coarse particles will reduce the compressibility of the soil in proportion to the coarse fraction present in the whole soil and will not affect the permeability of the soil for the range investigated. If the coarse fraction exceeds the limiting percentage, the void ratiovertical effective stress path will also start to deviate from the predicted path. An expression has been developed to estimate approximately the deviating pressure, and it is found to depend on the soil type as well as the percent clay fraction.

Keywords:
liquid limit, consolidation, void ratio, permeability

Paper ID: JTE12014J
DOI: 10.1520/JTE12014J
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