摘要
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。
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 the maximum shear stress is obtained.Stress decrease of the interface occurres after the curve reaches to the peak,which show that the interface with the character of strain softening.Shear strength of the interface is significantly lower than that of the deposits.The finite difference and strength reduction methods were adopted to analyze the stability of the accumulation slope under natural,reservoir filling as well as reservoir filling and seismic conditions.And three dimensional shapes of potential unstable body under different conditions were put forward.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2010年第3期392-396,共5页
Journal of China Coal Society
基金
中国科学院工程地质力学重点实验室开放基金资助项目
华北水利水电学院高层次人才引进项目
关键词
堆积体边坡
原位直剪试验
三维稳定性分析
基-覆界面
潜在滑动面
强度折减法
accumulation body slope
in situ direct shear test
three-dimensional stability analysis
interface between overburden layer and bedrock
potential sliding surface
strength-reduction method
