不同排水条件下饱和软黏土动力特性试验研究

以宁波轨道交通1号线沿线软黏土为研究对象, 开展了不同动应力幅值下的循环动三轴试验, 研究了不排水和部分排水对饱和软黏土累积塑性应变、动孔压、动弹性模量及动阻尼比的影响. 结果表明: 在排水条件下对饱和软黏土的动力特性影响较大, 尤其是动孔压; 随着振动次数的增加, 部分排水条件下的动孔压存在一个峰值, 动孔压先增大后减小; 当动应力幅值较大时, 部分排水条件下累积塑性应变和动阻尼比小于不排水条件下的结果, 动弹性模量则大于不排水条件下的值; 对试验结果进行归一化处理后, 获得了动弹性模量、动阻尼比以及累积塑性应变的内在关系.

Effects of Drainage Condition on Dynamic Characteristics of Saturated Soft Clay under Cyclic Load

Based on the cyclic triaxial tests under different dynamic stress amplitude, the effects of drainage condition on several factors is investigated. The process consists of the cumulative plastic strain, dynamic pore pressure, dynamic elastic modulus and dynamic damping ratio of soft clay around the Ningbo Rail transit Line 1. The results show that the drainage condition has a great impact on the dynamic characteristics of saturated soft clay, especially on the dynamic pore pressure. The dynamic pore pressure has a peck value with the increasing number of cycles under partially drainage condition. It increases firstly followed by decreasing with the increasing number of cycles. When the dynamic stress amplitude grows larger, the cumulative plastic strain and dynamic damping ratio under partially drainage condition become less than those of un-drained condition, while the dynamic elastic modulus turn larger than that of un-drained condition. In this paper, the intrinsic relationship is finally obtained among the dynamic elastic modulus, dynamic damping ratio and cumulative plastic strain after the process of normalization.