A series of true triaxial tests is conducted by using TSW-40 type true triaxial apparatus to research the strength characteristics of silty clay under complex stress paths. The stress-strain curves change law of silty clay in true triaxial tests is researched. The influence of moisture content

confining pressure and intermediate principal stress ratio on the strength of silty clay is discussed. The difference among Mohr-Coulomb strength criterion

twin shear strength criterion and experiment results on the plane is compared and analyzed. The results show that the generalized shear stress-shear strain curves of silty clay mainly perform as strain hardening type. The strength of silty clay increases with the increase of the intermediate principal stress ratio and the consolidation confining pressure

but decreases with the increase of moisture content. The strength envelope on the plane gradually expands outward with increasing hydrostatic pressure

gradually shrinks inward with increasing moisture content. The comparative analysis results show that the strength of the soil is smaller than test results when Mohr Coulomb strength criterion

is larger when twin-shear strength criterion is adopted.