露天煤矿顺倾软岩边坡失稳时空演化机制与稳定性计算方法

Mastering the slope instability evolution mechanism and evaluate its stability scientifically is the key to efficiently solve the treatment problem of the dip bedded soft rock slope in surface coal mines. In this project, fully considering the spatio-temporal variability of slope stress field, seepage field, moisture content of weak layer and shear strength parameter affected by these three factors, the mechanics characteristics of the weak layer for deferent moisture contents and stress levels by tests, then the softening, creep and seepage models are built under the different moisture contents through the multi-parameter fitting method. Through similar materials simulation, numerical simulation and tracer method, the laws of spatiotemporal evolution of the slope stress, seepage and deformation field are revealed, the instability spatio-temporal evolution mechanism is demonstrated, then the slope failure criteria considering both creep-tensile failure and creep-shear failure is built. The spatio-temporal distribution models about moisture content and stress of weak layer are built by the multivariate regression analysis, then the spatio-temporal evolution model of the shear strength parameter of the weak layer is deduced. The surface equation of the sliding surface is built by analysis of its spatial form and using interpolation method, based on which the mechanical assumptions on the landslide boundary and between the adjacent columns are constructed, then a 3D static stability calculation method based on the ultimate balance theory for the dip bedded soft rock slope is derived. Combined with the spatio-temporal evolution of the of the shear strength parameter of the weak layer is constructed, which can establish the theory and application foundation for the engineering design, the treatment and the landslide forecast of the kind of slope.

明确边坡失稳演化机制，科学评价其稳定性是解决露天煤矿顺倾软岩边坡治理难题的关键。项目充分考虑边坡应力场、渗流场、弱层含水率以及受三者共同影响的弱层抗剪强度参数的时空变异性，测试弱层在不同含水率与应力水平的力学特性，通过多参数拟合，建立应力-渗流耦合作用下弱层的软化、蠕变与渗流模型；通过相似材料模拟、数值模拟并借助示踪剂法，揭示边坡应力场、渗流场及变形场的时空演化规律，阐明边坡失稳时空演化机制，提出兼顾蠕变-拉裂和蠕变-剪切破坏的边坡失稳判据；通过多元回归，建立弱层含水率与弱层面应力的时空分布模型，推导弱层抗剪强度参数时空演化模型；分析滑面空间形态并插值建立其曲面方程，提出合理的滑体边界及条柱间力学假设条件，推导基于极限平衡理论的顺倾软岩边坡三维静态稳定性计算方法；结合弱层抗剪强度参数时空演化规律，建立顺倾软岩边坡时空稳定性计算方法。为该类边坡工程设计、治理及滑坡预测预报奠定理论与应用基础。

明确边坡失稳演化机制，科学评价其稳定性是解决露天煤矿顺倾软岩边坡治理难题的关键。项目以蒙东地区典型软岩露天煤矿为工程背景，综合采用现场调研、室内试验、物理模拟试验、数值模拟、理论分析等方法和手段，对露天煤矿顺倾软岩边坡失稳演化机制与稳定性计算方法展开系统研究。在分析顺倾软岩边坡工程地质特征的基础上，测试了弱层及泥岩的蠕变力学特性，构建了泥岩的蠕变本构模型，建立了边坡岩体抗剪强度参数多重反演方法；在建立滑体空间形态方程的基础上，推导了含顺倾弱层边坡三维稳定性计算方法，揭示了边坡形态等参数对含顺倾弱层边坡三维稳定性影响规律；提出了中间桥对边坡三维支挡效应的二维等效方法，建立了中间桥支挡边坡三维稳定性计算方法，揭示了中间桥空间形态参数与边坡稳定性的定量关系并形成了规律性认识；分析了支撑煤柱的失稳演化规律，提出了煤柱失稳判据，创建了端帮开采条件下边坡稳定性计算方法；在滑坡演化过程中获得的位移参数的随机特性，构建了基于马尔科夫理论构建预警方法并提出了基于马尔科夫链理论的滑坡判据，给出了预警模型的评价标准。研究成果可为类似软岩边坡稳定性分析与工程设计提供理论基础，还可为及时、准确实施滑坡预警并采取治理措施提供科学依据。