东明露天煤矿北帮富水软岩边坡稳定性研究

【作者】 郭飞；

【导师】 侯克鹏； 钟晓勇；

【作者基本信息】 昆明理工大学 ， 矿业工程（专业学位）， 2024， 硕士

【摘要】 露天煤矿在生产建设过程中,边坡稳定性受泥岩软弱岩层、地下水、地质构造等诸多因素影响,直接关系到矿山安全生产和经济效益,尤其是对松散类软岩露天煤矿边坡稳定性影响尤为突出。东明露天煤矿属于典型富水软岩边坡露天矿山,矿区北帮工作帮主要以软岩类为主,地下水侧向径流补给量大,易发生顺层失稳滑坡。本文以东明露天煤矿北帮为研究对象,通过资料搜集、开采现状存在问题分析、边坡破坏影响因素和破坏机理分析、刚体极限平衡分析方法和FLAC3D数值模拟等研究方法和手段,系统性的研究了东明露天煤矿北帮边坡稳定性,采用疏干降水和帷幕注浆两种地下水控制措施,分析地下水水位控制后渗流场特征和稳定性系数。论文主要成果及结论如下:(1)地下水是该矿山北帮边坡破坏的主要影响因素,在地下水作用下,边坡在泥岩软弱岩层形成滑动面,主要破坏方式是在滑动面后缘形成圆弧形剪切,在滑坡体坡脚处发生剪出,“坐落滑移式”是该露天矿山软岩边坡的主要滑动模式。(2)通过采用刚体极限平衡法和FLAC 3D数值模拟,分析了北帮边坡在地下水影响下的边坡稳定性情况。结果表明:极限平衡计算北帮在含水状态条件下边坡安全系数Fs分别为1.08、1.02、1.05、1.07,北端帮边坡整体存在一定滑坡风险;土层多级台阶沿泥岩软弱岩层滑动时,在含水状态下边坡安全系数Fs小于1.0,土层多级台阶处于不稳定状态,易发生沿软弱岩层滑坡的风险。(3)采用FLAC 3D数值模拟分析,北帮上部边坡岩土体向边坡临空面的应力释放形成位移变形和坡顶近地表外侧区域的沉降位移变形,最大应力应变和变形区域位置主要位于边坡深部泥岩弱层区域和深部煤层区域。由于水直接渗入边坡土层和岩层的孔隙、裂隙中,泥岩软弱层形成滑面,岩体剪切强度降低,多级台阶高边坡区域坡脚处剪应力集中表现,对局部边坡片帮和滑塌带来一定安全风险。(4)通过疏干降水和帷幕注浆两种地下水控制措施,边帮涌水出露水位控制在+550m水平,地下水水位得到控制,整体边坡稳定性系数达到2.18,较地下水富水条件下边坡稳定性得到明显提高。更多还原

【Abstract】 In the process of production and construction of open-pit coal mine,the slope stability is affected by many factors such as weak interlayer,groundwater and geological structure,which is directly related to mine safety production and economic benefits,especially for the slope stability of loose soft rock open-pit coal mine.Dongming Open-pit Coal Mine is a typical open-pit mine with water-rich soft rock slope.The northern slope of the mining area is mainly composed of weak layered rocks.The geological structure is developed,and the lateral runoff recharge of groundwater is large,which is prone to bedding instability landslide.In this thesis,the northern slope of Dongming Open-pit Coal Mine is taken as the research object.Through data collection,analysis of existing problems in mining status,analysis of influencing factors of slope failure,rigid body limit equilibrium analysis method and FLAC 3D numerical simulation,the stability of the northern slope of Dongming Open-pit Coal Mine is systematically studied.Two groundwater control measures,dewatering and curtain grouting,are used to analyze the seepage field and stability coefficient after groundwater level control.The main results and conclusions are as follows :(1)Groundwater is the main factor affecting the failure of the northern slope of the mine.Under the action of groundwater,the slope forms a sliding surface in the mudstone weak rock layer.The main failure mode is to form an arc-shaped shear at the trailing edge of the sliding surface and cut out at the slope toe of the landslide body.The " sitting slip type " is the main sliding mode of the soft rock slope of the open-pit mine.(2)By using the rigid body limit equilibrium method and FLAC 3D numerical simulation analysis,the slope stability of the north slope under the influence of groundwater is analyzed.The results show that the safety factor Fs of the north end slope under the condition of water-bearing state calculated by limit equilibrium method are 1.08,1.02,1.05 and 1.07,respectively,and there is a certain landslide risk in the north end slope as a whole.When the multi-stage steps of the soil layer slide along the weak layer of the bedrock,the slope safety factor Fs is less than 1.0under the water-bearing state,and the multi-stage steps of the soil layer are in an unstable state,which is prone to the risk of landslides along the weak rock layer.(2)By using FLAC 3D numerical simulation analysis.The stress release from the rock and soil mass of the upper slope of the north slope to the free face of the slope forms the displacement deformation and the settlement displacement deformation of the near-surface lateral area of the slope top.The maximum stress strain and deformation area are mainly located in the deep mudstone weak layer area and deep coal seam area of the slope.Its deformation is mainly controlled by the weak layer of mudstone The shear stress concentration at the toe of the multi-step high slope area brings certain safety risks to the local slope spalling and collapse.(3)Through dewatering and curtain grouting two groundwater control measures,the water level of the water gushing from the side is controlled at the level of + 550 m,the groundwater level is controlled,the overall slope stability coefficient reaches2.18,and the slope stability is obviously improved.更多还原