循环荷载下老黏土的动力特性试验研究

The Dynamic Response of Old Cohesive Soil in Wuhan under Cyclic Loading

本文利用GDS动态循环三轴仪施加竖向循环荷载对武汉地区具有代表性的老黏土进行试验研究,主要分析了老黏土在模拟地铁振动荷载作用下的动力特性。通过对孔隙水压力变化和残余应变发展曲线的分析,探讨了下不同固结比、动应力比、卸荷比等因素对老黏土动力特性的影响,并综合各因素总结出老黏土的动力响应规律;通过与软粘土和淤泥质土的已有研究成果进行对比分析与讨论,提出了合适老黏土的孔隙水压力发展模型及残余应变经验公式。本文的研究对地下工程设计中认识老黏土的物理力学特性等具有一定意义。

Groups of triaxial cyclic shear tests for the representative old cohesive soil in Wuhan were carried out, to study the dynamic deformation and mechanical properties of the old cohesive soil subjected to cyclic loading. With analyzing the residual strain curve and pore pressure curve, the influence factors such as the behaviors of consol idation pressure ratio, dynamic stress ratio, unloading ratio on the dynamic behaviors of the old cohesive soil were ex plored in detail. Moreover, compared with researches on soft clay and silt clay, the possible development model of pore pressure and the empirical formulas of residual strain of old cohesive soil are presented by normalizing test data. It may be of benefit to further understanding the physical and mechanical characteristics of old cohesive soil under cy clic loading in underground engineering.