Volume change and shear behavior of unsaturated silt and sand/clay mixed soil under triaxial stress conditions

摘要

In order to investigate the performance of Kohgo's elastoplastic model for unsaturated soils, we carried out triaxial compression and isotropic consolidation tests for two unsaturated soils, namely DL clay and an artificial soil mixed with Japanese (Toyoura) standard sand and a commercial kaolinite. The triaxial compression tests were conducted under the different initial densities and different drained conditions and they are divided into 4 series of tests (DU, D, S and M) by the used conditions. The results of triaxial compression tests showed that the application of suction had no influences to elastic deformations but had the effect of inhibition to plastic deformations. Moreover, the unsaturated soils might also possess the critical state condition where the influence of difference of initial densities disappeared, the loose and dense specimens could have an unique soil water retention curve and they could occupy the same shear strength if they had the same values of suction and confining pressures. The consolidation tests with two constant values of suction were also conducted. The consolidation test results supported the results of the triaxial tests that the application of suction influenced only plastic deformations.