Experimental investigation of thermo-mechanical behaviors of deep-sea clay from the South China Sea

Abstract

Thermal-induced geotechnical problems in offshore engineering, such as marine energy exploitation and submarine nuclear waste disposal, have recently attracted increasing attention. In this study, a series of triaxial compression tests subjected to various temperatures were performed on the reconstituted deep-sea clay recovered from the South China Sea (SCS). The thermo-mechanical behaviors, particularly pore water pressure, undrained shear strength, and yield characteristics, were investigated. The results indicated that the undrained shear strength depended much on the drainage conditions at different temperatures. Under undrained heating conditions, the temperature effect on the normally consolidated (NC) clay was more remarkable than that on the overconsolidated (OC) clay. And the temperature-induced excess pore pressure, which was analyzed by the empirical models for both NC and OC clay, led to special quasi-overconsolidated (QOC) behaviors. Furthermore, based on the Modified Cam Clay (MCC) model and the test results, two normalized strength models were proposed, and it was proved to be able to well predict the critical undrained shear strength of deep-sea clay from the SCS under drained and undrained heating conditions. It is believed that the work presented in this paper would have some contribution to the design and construction of deepwater engineering.