Experimental Study on Dynamic Strength Regional Characteristics of Undisturbed Loess Based on the Mohr-Coulomb Failure Criterion

摘要

Based on Mohr - Coulomb failure criterion, dynamic strength characteristic of undisturbed loess in Xining, Lanzhou, Xiji and Xian was studied through dynamic triaxial test. And the regional characteristics of void ratio, natural moisture content, plasticity index and dynamic shear strength with different vibration frequency and natural conditions were analyzed. The research shows that dynamic shear strength of loess increases when consolidation stress rises under the same water content condition. However the increase trend is not proportional relationship. Initial void ratio and water content of loess under natural state rises from northwest to southeast, and dynamic cohesive force enhances. On the contrary, internal friction angle decreases with the change of characteristic. With the increasing trend of disturbed loess's clay content from northwest to southeast, dynamic cohesive force increases and internal friction angle decreases in the different amplitude. The conclusion enriches and develops the evaluation theory of loess regional dynamic characteristic and it is a universal method to reduce cost of different loess regional classification.