摘要
为明确软弱夹层中岩土体应变软化特性对矿山边坡变形体稳定性的影响,基于线性应变软化M-C模型,提出了容重增加法分析矿山边坡变形体渐进破坏的方法。以四川某石灰石矿区高边坡平台变形体稳定性分析为研究对象,选取两个典型的工程地质剖面建立矿山边坡稳定性FLAC数值计算模型,分析了软弱夹层含水量对矿山边坡变形体稳定性的影响规律,并与极限平衡法进行对比,验证容重增加法计算边坡安全系数的有效性和优越性,最后以剪应变增量为变化指标,描述了矿山边坡变形体渐进破坏的全过程。结果表明:①软弱夹层含水量增加,会增大边坡失稳的风险,同时其应变软化特性对边坡安全系数的影响更显著;②容重增加法初始状态下的边坡安全系数与极限平衡法峰值状态下的边坡安全系数计算值相当,极限平衡法采用残余强度指标计算得到的边坡稳定性结果偏于保守,建议采用容重增加法稳定状态下边坡稳定性的计算结果评价边坡变形体的稳定性;③随着计算时步的不断增加,基于线性应变软化M-C模型的容重增加法,可以全面、直观地描述矿山边坡变形体渐进破坏的全过程,可为矿山边坡安全评估提供依据。
In order to research the influence of strain softening characteristics of rock and soil in weak interlayer on the stability of the deformed rock body on the mine slope,based on the linear strain softening M-C model,this paper proposes a gravity increase method to analyze the progressive failure of deformed rock body on mine slope.Taking the stability analysis of the deformed rock body on a high slope in a limestone mine area in Sichuan as the study object,the paper establishes the FLAC numerical calculation model for two typical engineering geology profiles of the slope.Then the paper studies the influence of water content in the weak interlayer on the stability of deformed rock body,and verifies the validity as well as superiority of the proposed method on the calculation of safety factor with comparison of the results from traditional strength reduction method.Finally,the paper describes the entire process of progressive failure of the in-vestigated slope by resorting to the increment in shear strain.The results show that with an increase in water content of the weak interlayer,the risk of slope failure would be increased,and meanwhile the effect of strain soften on the safety factor becomes more significant;the values of safety factor by the gravity increase method at initial state are close to those by limit equilibrium method at peak state.The values of safety factor using residual strength indexes are usually conservative.It is recommended to evaluate the stability of the deformation body by using the slope stability calculation results at the steady state based on gravity increase method;with an increase in calculation step,the gravity increase method based on the linear strain soften M-C model is able to give an intuitive description on the progressive failure of deformed rock body,which could provide a basis for safety assessment of mine slope.
作者
何怡
郭力
马冲
HE Yi;GUO Li;MA Chong(Civil Engineering Department,Luoyang Institute of Science and Technology,Luoyang 471023,China;School of Mathematics and Physics,China University of Geosciences(Wuhan),Wuhan 430074,China)
出处
《安全与环境工程》
CAS
北大核心
2020年第2期162-167,174,共7页
Safety and Environmental Engineering
基金
湖北省自然科学基金项目(2018CFB385)。
关键词
矿山边坡稳定性
软弱夹层
岩土体应变软化
容重增加法
极限平衡法
安全系数
数值计算
mine slop stability
weak interlayer
strain softening of rock and soil
gravity increase method
limit equilibrium method
safety factor
numerical calculation
