粗粒坝料边坡稳定分析强度指标研究

Study of shearing strength parameters of coarse grained materials in slope stability analysis

分别采用线性、非线性强度指标,对几座典型高堆石坝边坡进行稳定计算,并分析了计算结果产生差异的内在原因;认为粗粒土坝坡最危险滑弧位置较浅,低围压区的抗剪强度特性才是决定坝坡是否稳定的关键。在国内外多个堆石坝料强度统计资料基础上,认为De Mello幂函数强度准则更合理地反映不同应力范围抗剪强度的非线性特征;通过拟定不同坝高、坡比的坝坡进行稳定计算,确定了土石坝不同坝高潜在最危险滑块的工作应力范围,并建议了基于该应力范围的线性强度指标取值,其边坡稳定分析最小安全系数与非线性强度指标的计算值基本相当。

This paper uses both linear and nonlinear strength parameters in several typical rockfill dams＇ slope stability analysis,clarifies the intrinsic factors that lead to the differences;the position of critical sliding surface is considered to be shallow,thus,shearing strength of coarse grained materials at low confining pressure is vital in slope stability analysis.Based on statistics of rock-fills in several typical rockfill dams at home and abroad,power function strength criterion proposed by De Mello is thought to be more reasonable to express coarse grained soils＇ strength in its whole confining pressure range.By drafting dam slopes with different heights and gradients,working stress ranges are determined.This study suggested a method to specify the linear strength parameters based on working stress ranges,these linear strength parameters have a good consistent with nonlinear parameters in slope stability analysis.