考虑节理岩体各向异性的边坡力学特征分析及应用

发布时间：2018-10-20 16:47

【摘要】：边坡岩体通常含有大量不同尺度、分布复杂的结构面,这些结构面导致了岩体的各向异性,忽略其各向异性将与实际有较大偏差。对于极其复杂的岩体结构,在实际岩体工程分析中,通常需要抓住影响岩体变形和破坏的主要因素,通过一定科学方法研究其宏观力学特征。为了探讨节理分布对边坡力学特征的影响规律,本文基于等效连续介质模型,将节理岩体等效为各向异性弹塑性体,建立各向异性渗流-应力耦合模型,通过数值模拟研究考虑节理岩体各向异性的边坡力学特征,并结合工程实例进行分析。论文的主要研究工作及主要结论如下：1.概述了工程岩体质量分级、岩体参数确定及数值计算模型的研究现状,分析了目前工程应用中存在的主要问题,并确定了本文的研究思路和研究内容。2.假设节理岩体存在一个优势节理方向,建立了平面应变问题下,各向异性岩体渗流-应力耦合模型,并提出了基于COMSOL有限元分析软件的边坡力学特征数值计算方法。通过数值模拟分析了考虑节理岩体各向异性的边坡应力场、位移场和渗流场等分布特征,并根据各向同性莫尔库伦和最大拉应力破坏准则,研究了边坡损伤破坏规律。研究发现,优势节理方向对边坡力学特征起控制作用,在进行岩体力学分析时不能忽略其各向异性。3.以抚顺西露天矿南帮为例,通过室内岩石力学实验、现场结构面测试及渗透试验,采用节理岩体网络模型,考虑岩体REV尺寸效应,综合确定了岩体变形和渗透参数,实现了工程岩体参数表征；建立了西露天矿南帮E1200剖面各向异性数值模型,通过数值模拟与传统各向同性模型进行了对比分析。结果表明：各向异性模型计算的潜水面更接近实际,且损伤演化规律与实际吻合较好；各向同性模型计算结果与实际有较大偏差,即各向异性模型具有良好的工程应用前景。4.进行了三维边坡力学特征初探。以某露天矿边坡为背景,建立了层状岩体边坡三维横观各向同性模型,引入三维Hoffman各向异性破坏准则,对不同岩层倾角下三维边坡损伤区进行了数值模拟。研究发现,顺倾层状边坡更容易发生整体性损伤破坏,反倾层状边坡多存在小范围局部损伤,整体相对稳定。
[Abstract]:Slope rock mass usually contains a large number of structural planes with different scales and complex distribution, which leads to the anisotropy of rock mass, and neglecting the anisotropy of rock mass will deviate greatly from the actual situation. For the extremely complex rock mass structure, in the actual rock mass engineering analysis, it is usually necessary to grasp the main factors that affect the deformation and failure of the rock mass, and to study the macroscopic mechanical characteristics of the rock mass by a certain scientific method. In order to study the influence of joint distribution on the mechanical characteristics of slope, the coupling model of anisotropic percolation and stress is established based on the equivalent continuum medium model, and the jointed rock mass is equivalent to anisotropic elastoplastic body. The mechanical characteristics of slope considering anisotropy of jointed rock mass are studied by numerical simulation. The main research work and main conclusions are as follows: 1. This paper summarizes the research status of engineering rock mass quality classification, rock mass parameter determination and numerical calculation model, analyzes the main problems existing in engineering application at present, and determines the research ideas and contents of this paper. Assuming that there is a dominant joint direction in jointed rock mass, a coupling model of seepage and stress for anisotropic rock mass under plane strain problem is established, and a numerical calculation method of slope mechanical characteristics based on COMSOL finite element analysis software is proposed. The distribution characteristics of slope stress field, displacement field and seepage field considering anisotropy of jointed rock mass are analyzed by numerical simulation. The damage and failure law of slope is studied according to isotropic Mohr-Coulomb and maximum tensile stress failure criterion. It is found that the dominant joint direction controls the mechanical characteristics of the slope and the anisotropy of the rock mass can not be neglected in the analysis of rock mass mechanics. Taking the south side of Fushun West Open-pit Mine as an example, the deformation and permeability parameters of rock mass are determined synthetically by indoor rock mechanics experiment, field structure plane test and permeability test, using jointed rock mass network model and considering the REV size effect of rock mass. The parameter representation of engineering rock mass is realized, and the anisotropic numerical model of E1200 section of the south side of west opencast mine is established, and the comparison between the numerical simulation and the traditional isotropic model is carried out. The results show that the phreatic surface calculated by the anisotropic model is closer to the reality and the damage evolution law is in good agreement with the actual situation, and the calculation result of the isotropic model is quite different from the actual one, that is, the anisotropic model has a good prospect of engineering application. The mechanical characteristics of three-dimensional slope were studied. A three-dimensional transversely isotropic model of layered rock slope is established based on an opencast slope, and the three-dimensional Hoffman anisotropic failure criterion is introduced to simulate the three dimensional slope damage zone with different dip angles. It is found that the downdip stratified slope is more prone to global damage and the reverse layer slope usually has a small area of local damage and the whole is relatively stable.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU45

【相似文献】