Experimental Study on Unconfined Compressive and Cyclic Behaviors of Mucky Silty Clay with Different Clay Contents

Abstract

In this study, the unconfined compressive and cyclic behaviors of saturated mucky silty clay from the reclamation area of Dalian, which has two different clay contents, are investigated using the static and dynamic triaxial test systems. The influence of clay content on the residual strain and residual pore water pressure of undisturbed and reconstituted specimens are discussed. A scanning electron microscope (SEM) is used to observe the microstructures of the specimens. The unconfined compressive test results of the specimen with low clay content exhibits “collapse” characteristics. However, the corresponding specimen with high clay content exhibits a “sustained hardening” trend. The dynamic test results indicate that the residual pore water pressure, residual strain, and difference in the residual strain between the undisturbed and reconstituted specimens increase as the load increases. The ratio of the reconstituted residual strain to the undisturbed residual strain increases as the load increases, and this ratio is larger than the sensitivity of the soil. The residual strain of the specimen with high clay content exceeds the corresponding value of the specimen with low clay content. The stiffness degradation of the high clay content specimen is more obvious than that of the low clay content specimen. A power function-based residual strain model that contains the cyclic stress ratio (CSR) and number of cycles (N) is proposed. This model can be used to describe the residual strain with a CSR less than the critical CSR.