降雨入渗条件下曼家寨东帮采场软岩边坡的稳定性研究

发布时间：2018-03-14 09:01

本文选题：饱和-非饱和　切入点：降雨入渗　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：露天矿边坡的稳定直接关系到矿山工人的安全与企业的经济效益,是保证矿山企业正常生产的先决条件。边坡发生失稳的原因是多方面的,而降雨是发生滑坡的常遇诱导因素。本文在国内外学者研究的基础上,以曼家寨东帮采场软岩边坡为研究对象,针对其在降雨过后曾发生局部垮塌、出现坡面裂缝现象,结合饱和-非饱和渗流理论、饱和-非饱和抗剪强度理论,进行相关物理力学试验,分析降雨作用下该露天矿边坡失稳破坏的机理。选取典型区域运用Geo-studio中的SEEP模块计算降雨条件下该边坡的渗流场,分析降雨过程中边坡入渗的规律。以渗流计算为前提,结合Fredlund和Morgenstern提出的饱和-非饱和抗剪强度理论,运用Flac3d对边坡降雨条件下的稳定性及滑动面进行计算,分析降雨对边坡稳定性的影响规律。本文的主要研究内容如下:(1)通过查阅相关文献,了解国内外对降雨入渗下边坡稳定的研究现状。总结降雨入渗下边坡稳定性影响的理论:以达西定律与能量守恒定律为基础,推导出适用于软岩边坡的饱和-非饱和渗流微分方程,选取相应的定解条件;归纳总结了适用于软岩边坡的饱和-非饱和抗剪强度理论。为后续数值模拟分析提供理论基础。(2)研究区工程岩体力学特性与渗透特性分析:基于曼家寨边坡露天开采技术条件,结合边坡现场调研,通过对工程岩体开展室内与现场试验,确定合理的边坡宏观岩体力学参数与渗透参数,为后续数值模拟分析提供可靠的计算参数。(3)降雨条件下边坡瞬态渗流场渗流特性分析:结合工程区域降雨特征,运用Geo-studio软件的SEEP模块,对不同降雨强度、不同降雨持续时间下边坡岩体暂态饱和区、孔隙水压力分布的变化规律进行模拟分析。研究认为:降雨条件下边坡表层区域受降雨影响严重,影响区域与影响程度受降雨时间与降雨强度共同控制;暂态饱和区是考虑降雨作用下边坡失稳的重要因素,降雨历时相同时,降雨强度越大形成暂态饱和区面积越大;边坡受降雨影响的范围首先是坡脚,然后是坡顶,最后才向坡体内部延伸。(4)降雨入渗对边坡稳定性影响的分析:将渗流场的孔隙水压力引入基于饱和-非饱和抗剪强度理论的稳定性计算中,运用Flac3D强度折减法对降雨条件下边坡的稳定性进行分析,其中重点考虑不同降雨时间下的位移场、潜在滑移面、安全系数的变化,并对不同降雨条件下边坡的稳定性进行了评价,为决策者提供了可靠的理论依据。(5)根据对该边坡降雨条件下渗流计算与稳定性计算结果,针对降雨条件下边坡的潜在危害,提出相应的防护治理措施。
[Abstract]:The stability of open pit slope is directly related to the safety of mine workers and the economic benefits of enterprises, and is a prerequisite to ensure the normal production of mining enterprises. Based on the research of domestic and foreign scholars, this paper takes the soft rock slope of Manjiazhai East Slope as the research object, aiming at the phenomenon of local collapse and slope surface crack after rainfall. Combined with saturated-unsaturated seepage theory and saturated-unsaturated shear strength theory, relevant physical and mechanical tests were carried out. This paper analyzes the mechanism of slope instability and failure under rainfall. The seepage field of the slope under rainfall condition is calculated by using SEEP module of Geo-studio in typical area, and the law of slope infiltration during rainfall is analyzed. Combined with the saturated-unsaturated shear strength theory proposed by Fredlund and Morgenstern, the stability and sliding surface of slope under rainfall condition are calculated by Flac3d. The main contents of this paper are as follows: 1. To understand the research status of slope stability under rainfall infiltration at home and abroad, summarize the theory of slope stability under rainfall infiltration: based on Darcy's law and energy conservation law, The saturated-unsaturated seepage differential equation suitable for soft rock slope is derived, and the corresponding definite solution condition is selected. The saturated-unsaturated shear strength theory suitable for soft rock slope is summarized, which provides a theoretical basis for subsequent numerical simulation analysis. The mechanical and permeable characteristics of engineering rock mass in the study area are analyzed: based on the technical conditions of open-pit mining of Manjiazhai slope, Based on the field investigation of the slope, through the laboratory and field tests on the engineering rock mass, the reasonable mechanical parameters and permeation parameters of the slope macroscopic rock mass are determined. In order to provide reliable calculation parameters for subsequent numerical simulation analysis, the seepage characteristics of transient seepage field in slope under rainfall condition are analyzed. According to the rainfall characteristics of engineering area, the SEEP module of Geo-studio software is used to analyze the different rainfall intensity. The variation law of pore water pressure distribution in transient saturated area of slope rock mass under different rainfall duration is simulated and analyzed. It is considered that the surface area of slope is seriously affected by rainfall under rainfall condition. The influence area and influence degree are controlled by rainfall time and rainfall intensity together; transient saturation region is an important factor of slope instability under the consideration of rainfall. When rainfall duration is the same, the larger rainfall intensity is, the larger the area of transient saturation zone is. The slope is affected by rainfall first at the foot of the slope, then at the top of the slope. Finally, the influence of rainfall infiltration on slope stability is analyzed. The pore water pressure of seepage field is introduced into the stability calculation based on saturated-unsaturated shear strength theory. The stability of slope under rainfall condition is analyzed by Flac3D strength reduction method, in which the variation of displacement field, potential slip plane and safety factor under different rainfall time are taken into account. The stability of slope under different rainfall conditions is evaluated, which provides a reliable theoretical basis for decision-makers. According to the results of seepage calculation and stability calculation under rainfall condition, the potential damage of slope under rainfall condition is pointed out. The corresponding protective measures are put forward.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD854.6

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