交通荷载作用下K0固结硬黏土动力特性研究

Cyclic response of K-consolidated stiff clay under traffic loading

利用GDS动三轴仪及空心圆柱扭剪仪对K0>1的英国Gault硬黏土和Kimmeridge硬黏土进行了不排水条件下大周数(1万次)循环加载试验,研究了交通荷载作用下循环应力比及主应力轴旋转对K0固结原状硬黏土动力特性的影响。试验结果表明:与软黏土相比,硬黏土具有较为明显的脆性特征;随着循环应力比的增大,其动力变形响应可分为"稳态"、"亚稳态"和"非稳态"等三种类型。在主应力轴旋转条件下,硬黏土轴向应变在拉伸侧不断发展,回弹模量逐渐减小,土体循环弱化程度较三轴加载条件下更为明显。

To study the effects of cyclic stress ratio and principle stress axis rotation on the undrained cyclic response characteristics of K0-consolidated stiff clay whose K0 is larger than 1,a series of traffic loading tests with a large number of cycles are conducted on the intact Gault and Kimmeridge clays by using the dynamic triaxial test system(DYNTTS)and the hollow cylinder apparatus(HCA).The test results indicate that the stiff clay has strong brittleness compared with the soft clay.With the increasing cyclic stress ratio,the cyclic deformation responses can be categorized into stable,metastable,and unstable patterns.Under the continuous rotation of the principle stress axis,the axial strain of the stiff clay is gradually accumulated at the extension side,and its resilient modulus is rapidly degraded.