吸力对非饱和高液限黏土-土工织物界面剪切特性的影响

Study on the interface shear characteristic between unsaturated high liquld limit clay and geotextiles considering the variation of suction

采用ZFY-1A型非饱和土应变控制式直剪仪,对非饱和高液限黏土-土工织物界面进行控制吸力的剪切试验,探讨基质吸力对筋土界面剪切特性的影响.研究结果表明,非饱和高液限黏土-土工织物界面的抗剪强度随着净法向应力、基质吸力的增大而不断提高,剪切位移-剪应力曲线表现出轻微的应变硬化软化特性.剪切过程中有水从试样中排出,净法向应力越大,含水量变化量Δwmax越大,基质吸力越大Δwmax反而越小.界面剪胀角随着基质吸力的增加而增大,随着净法向应力的增加而减小.界面强度随着平均界面剪胀角的增加而增大.最后确定了不同吸力值下的界面强度参数及强度公式.

A series of direct shear tests were performed using ZFY - 1 △ direct shear apparatus to in- vestigate the shearing resistance properties of high liquid limit clay - geotextile interface. Results of the study indicate that the peak shear strength of the soil - geotextile interface increases with the suction and net normal stress, curves of the shear stress and horizontal displacement show hardening - soften- ing behavior. Small decreases in water content were detected during shearing of the soil - geotextile in- terface shear tests, the higher the net stress, the larger the △W（max）, but the higher suction, the smal- ler the △w（max）. The interface dilation angle increases with matric suction and decreases with net nor- mal stress. The larger the average interface dilation angle, the higher the shear strength. Finally, we determine the interface parameters and interface strength formula in different sunction conditions.