关键词: 水泥土, 真三轴试验, 中主应力, 破坏准则, 强度

Abstract: To investigate the influence of intermediate principal stress factor b and minor principal stress on stress-strain characteristics of cement-soil, true triaxial tests are conducted under the conditions of constant minor principal stress ?3 and intermediate principal stress factor b. The results show that both the initial tangent modulus and the peak strength of cement-soil have positive correlation with b; however, the correlation between major principal strain at failure state and b is opposite. What’s more, there is a linear relationship between the peak strength and b, and the straight slope increases with the minor principal stress. For the same value of b, the initial tangent modulus, the peak strength and the major principal strain of cement-soil increase with increasing minor principal stress. The peak strength linearly rises with confining pressure as b is increased. The stress-strain curve changes gradually from softening type to hardening type, along with the increasing of confining pressure and intermediate principal stress. Failure stress ratio becomes lower due to the increased ?3 and intermediate principal stress factor b. Finally, the parameters of the generalized Mises yield criterion and the generalized Tresca yield criterion are obtained. Comparative analysis shows that the former criterion is superior to the latter criterion to describe the mechanical behavior of the cement-soil.

Key words: cement-soil, true triaxial test, intermediate principal stress, failure criteria, strength