关键词: 结构性软黏土, 应力状态, 固结试验, 无侧限抗压强度试验, 损伤变量, 扰动度

Abstract: Natural sedimentary clay can be disturbed in sampling and construction processes, resulting in the evolution of soil behavior. Although the disturbance degree and damage variable have been attracting many researchers’ attentions, but the relationship between them is still not clear. Here, the relationship between damage variable described by stress state and the disturbance degree represented by strength or deformation is discussed based on the experimental results. A marine clay, a typical quaternary sediments widely deposited in the Lianyungang coastal area, was selected and sampled with thin-walled tube method. The soil samples, trimmed into an appropriate size of 100 mm in length and 100 mm in diameter, were loaded quickly under different stress paths using GDS triaxial apparatus to simulate the damage process, and the consolidation and unconfined compression tests were conducted to investigate the disturbance degrees defined by the deformation and strength respectively. The relationships between damage variables controlled by the different stress paths and the disturbance degrees are developed. It is found that effect of the damage process on the compression curve is insignificant, and the unconfined compression strength decreases practically linearly with damage variables. These results imply that as stress path approaches to the failure line, the disturbance degree increases and the strength of soil decreases.

Key words: structural soft clay, stress state, consolidation test, unconfined compression strength test, damage variable, disturbance degree