上海粘性土剪切带倾角的试验研究

Experimental study on shear band inclination in Shanghai clay

采用可量测局部侧向应变的平面应变仪,对上海地区第②层褐黄色粉质粘土和第⑥层暗绿色粉质粘土的原状土样,进行固结不排水平面应变压缩试验,观察土样的局部化变形过程,量测剪切带倾角,研究剪切带倾角随固结压力的变化情况,计算剪切带倾角的传统土力学理论解并与实测值进行比较,根据剪切带内局部剪胀角的近似估算,初步研究剪切带内的变形机理,认为剪切带的形成与孔隙水的运动密切相关。

With the plane strain apparatus capable of measuring local lateral strain, a series of consolidation undrained plane strain compression tests were carried out on Shanghai undisturbed samples, from layer 2 consisting of yellow-dark silty clay and layer 6 consisting of dark green silty clay. The development of localized deformation was observed. The shear band inclination was measured and its variation with consolidating pressure was studied. The shear band inclination was also calculated by traditional soil mechanics and the results were compared with the measuring data. Based on approximate estimate of inner dilatant angle of shear band, deformation mechanism in shear band was investigated preliminarily. It was suggested that the formation of shear band is closely related with the movement of pore water.