大型堆积体原位直剪试验研究及三维稳定性分析

通过对一大型堆积体边坡进行原位直剪试验，发现剪切过程中部分位于剪切面上的超粒径颗粒被剪断或棱角处发生破碎，造成剪切位移有“跳跃”和剪切力突变现象；由于含石量的不同，堆积体内部剪切面起伏差大于基-覆界面剪切面起伏差；在堆积体内部直剪试验曲线中，剪应力达到最大值后进入塑性屈服阶段，基-覆界面处直剪试验曲线在达到峰值之后有一定的应力降，表现出一定的应变软化特性；基-覆界面的抗剪强度明显低于堆积体内部的抗剪强度。在对堆积体抗剪强度参数研究的基础上，考虑堆积体边坡的三维空间效应，采用有限差分强度折减法对其在自然状态、正常蓄水位、正常蓄水位+地震等工况下进行了三维稳定性分析评价，并得到了不同工况下堆积体边坡潜在三维滑体的空间轮廓。

In situ direct shear tests on the large-scale accumulation body and three-dimensional stability analysis of the slope

Took the large-scale accumulation slope of a hydropower station as an example,in situ direct shear tests were conducted.The results show that partial oversized grains of the sample are broken,which result in abrupt change of shear displacement and shear stress.Gurgitation difference of shear surface in the accumulation body is greater than that of the interface between overburden layer and bedrock.Direct shear test curves of accumulation body show that accumulation body become in plastic yield state while t...