LIQUEFACTION STRENGTH OF COARSE-GRAINED SOILSAS DETERMINED BY LARGE TORSIONAL TEST ANDTHE MEMBRANE PENETRATION EFFECT ON THE STRENGTH

摘要

The liquefaction strength of coarse-grained soil was investigated by using a large torsionalhollow cylinder test and a medium size triaxial test, and the membrane penetration effect onthe strength during the liquefaction test was also investigated. The results of liquefactiontests were discussed with the following two aspects; 1) The applicability of existing strengthcorrection method for membrane penetration effect that uses the test results without themembrane penetration correction. 2) The difference between the liquefaction strengths thatare obtained from the hollow cylinder test and the triaxial test.As to the applicability of existing strength correction method for the membrane penetrationeffect, it was concluded that the existing method underestimates somewhat the strength inboth type of tests. For the comparison of the liquefaction strengths between the two types oftest method, it was found that the liquefaction strength obtained from the large torsionalhollow cylinder test is higher than that from the medium triaxial test. Review is made onthe past studies of liquefaction strength difference between the hollow cylinder and triaxialtests on clean sands, and it was shown that the existing method to convert the triaxial testresult to that of torsional hollow cylinder test based on the studies with clean sand is notapplicable to the coarse-grained soil tested in this work.