Consolidation drainage of compacted clay based on multistage direct-shear test
Shear strength is an important mechanical parameter that determines the stability of soil and structures,such as foundations and slopes.Its value is generally obtained via direct-shear or triaxial tests.In these tests,three or four samples are typically used to measure the cohesion and internal friction angle of soil;the differences among samples will inevitably affect the accuracy of the results.Hence,this study improves the conventional direct-shear instrument so that it can be used to obtain the shear strength of a sample via repeated shears as well as the cohesion and internal friction angle of soil using the Mohr-Coulomb envelope.The results of multistage direct-shear tests for the consolidation drainage of compacted soil are compared with those of conventional direct-shear tests.The results show that the shear strength obtained from the multistage direct-shear test is slightly lower than that obtained from the conventional direct-shear test.Additionally,the error for the internal friction angle is±2.5°,which verifies that the multistage direct-shear scheme of consolidation drainage can be used to evaluate the shear strength of compacted soil.