山体岩石泥化夹层的动力抗剪强度

Cyclic Shear Strength of Weak Layer in Rock Mass

本文应用振动三轴试验研究了小浪底山体岩石泥化夹层原状岩芯试样在低频、高振次周期荷载作用下的变形和强度特性。试验结果表明,由于该泥化夹层与岩石的接触面是磨光面,因而它的静、动力抗剪强度都取决于接触面的强度;只要总剪应力不超过接触面的抗剪强度,泥化夹层的残余变形将随周期荷载作用次数的增加而渐趋稳定,不会因强度疲劳而产生突发性破坏。分别从泥化夹层本身的剪应变与接触面上的切向位移出发。分析了该泥化夹层岩芯试样的动力抗剪强度,发现其值随循环荷载振次增加而减小,但渐趋稳定,其最终稳定值与同样试验条件下的静抗剪强度值相当。

The cyclic behavior of the undisturbed rock samples with weak layers taken from Xiaolangdi Hydraulic Project was studied by using cyclic triaxial tests with low frequencies to high cyclic numbers and the results are presented in this paper. It is found that either the static or the cyclic shear strength is controlled by the strength along the interface between the weak layer and the rock. Based on the shear strain of the weak layer itself and the shear displacement along the interface between the weak layer and the rock, the cyclic shear strength was evaluated respectively and the results are close to each other.