Experimental investigation on the thixotropic effect on the mechanical recovery characteristics of clay-structure interface

The mechanical characteristics of the soil-structure interface have a crucial impact on the bearing capacity of offshore foundations. The thixotropy-induced strength recovery of remolded soils has a significant effect on the increase in the stability of the foundation. To explore the effects of thixotropy on the recovery characteristics of the soil-structure interfacial shear strength, a self-designed interfacial mechanical characteristic apparatus is designed in this study to perform a series of soil-structure interface tests on clays from the South China Sea and offshore Dalian, respectively. The relationship between the recovery of undrained shear strength and the change of interfacial shear strength is analyzed by the index of shear-resistant coarseness. And the effect mechanism of thixotropy on interfacial shear strength is discussed from the microscopic view. The test results indicated that the rate of increase of the soil-structure interfacial shear strength is higher than that of the undrained shear strength. The particle size index of the soil was found to significantly influence the strength recovery characteristics of the soil-structure interface. A higher clay content will accelerate the development of the interfacial shear strength. This article provides a deep insight into the thixotropic effect on the mechanical properties of the marine soil-structure interface.