汕头大学学报（自然科学版）

为探究汕头地区软黏土在经基坑开挖卸荷作用下的强度特征，利用应力路径三轴仪模拟原状软黏土在常规固结、超固结和卸荷路径下的力学响应规律.结果表明，汕头软粘土在不同固结压力下均出现应变软化现象，在低固结压力下，应变软化程度并不明显，在高固结压力条件下，应变软化现象明显，高固结压力会破坏土粒之间的胶结作用，从而导致应变软化程度增大.在不同固结压力下的应力-应变曲线规律相似，当轴向应变处于0～5%时，偏应力似线性增长；当轴向应变达到5%左右时，偏应力增长速率减小，且出现应力峰值所对应的轴向应变均处于8%～10%.基于上述结果，可为确定该地区软土峰值强度所对应的临界应变提供依据，从而更好地指导实际工程.

In order to explore the complex stress path of soft clay during foundation pit excavation in Shantou area, which leads to the difference of its strength characteristics, the mechanical properties and strength characteristics of the original soft clay were analyzed by triaxial compression unloading tests under different consolidation pressures. The results show that the strain softening of Shantou soft clay occurs under different consolidation pressures. At low consolidation pressure, the strain softening is not obvious, but at high consolidation pressure,the strain softening is obvious, and high consolidation pressure will destroy the cementation between soil particles, resulting in an increase in strain softening degree. The stress-strain curve is similar under different consolidation pressures. When the axial strain is 0 ～5%, the partial stress seems to increase linearly. When the axial strain reaches about 5%, the growth rate of deviatory stress decreases, and the axial strain corresponding to the peak stress is 8% ～10%.This can provide a basis for determining the critical strain corresponding to the peak strength of soft clay in the zone and guide practical engineering better.