采煤扰动下尾矿坝稳定性分析及动力响应研究

发布时间：2018-05-25 06:38

本文选题：尾矿库 + 稳定性分析　；参考：《北京科技大学》2017年博士论文

【摘要】：本文以司家营铁矿在采煤塌陷区上构建尾矿库为工程背景,开展了在采煤扰动条件下尾矿坝稳定性分析以及动力响应研究,并在地震荷载作用下进行流固耦合分析,研究尾矿坝地震液化机理与灾变失稳风险。本文研究工作以及所获得成果如下:首先,采用Midas GTS NX软件系统,建立了整个尾矿坝库区复杂三维地质模型,包括地层、新老不规则采空区、煤层以及未来采矿计划煤层:采用Visual Studio软件开发接口转换程序,将基于Midas建立的三维地质模型转换到FLAC3D系统中,由此建立了大尺度尾矿坝以及地基稳定性分析的数值模型。然后,根据尾矿坝地基当前阶段监测的地表沉降,采用遗传规划和遗传算法,建立智能等效岩体参数识别模型,获得在采煤影响下的尾矿坝地基基础等效岩体力学参数和原岩应力,为尾矿坝动静力稳定性分析和流固耦合数值模拟提供了可靠的岩体力学参数。第三,基于获得的尾矿坝地基等效岩体力学参数,针对尾矿坝筑坝和不筑坝两种工况,开展了尾矿库区在采煤过程中的稳定性分析。结果表明,尾矿库库区地基沉降受采矿扰动影响显著。随着煤层逐年开采,库区地表南部塌陷坑明显向西侧逐步扩大,筑坝后的坝体重力加剧尾矿坝地基沉降,在2015年南北两个塌陷区贯通,并在库区东南侧形成一个新的塌陷坑。预计2018年后最大沉降将达到4.85m,其中西坝体存在失稳风险,是整个库区最危险部位。第四,针对尾矿库2018年采矿结束后,开展地震对尾矿库稳定性影响的动力分析。根据坝基沉降和坝顶加速度的计算结果显示,不考虑渗流影响,仅地震对尾矿坝稳定性影响并不十分显著。最后,采用FLAC3D的Finn模型开展了地震作用下的流固耦合分析,并基于有效应力进行尾矿坝和地基基础的液化条件判断。根据超孔压比指标评价土体液化条件,由此获得了动荷载流固耦合条件下初期坝浸润面变化规律,从应力、位移、加速度、孔压、超孔压比等物理力学指标,对尾矿坝的震动液化进行综合分析和安全评价,为采煤塌陷区建造尾矿库的优化设计和安全运营管理提供科学依据。
[Abstract]:In this paper, the stability analysis and dynamic response of tailings dam under the condition of coal mining disturbance are carried out, and the fluid-solid coupling analysis is carried out under the action of earthquake, taking the construction of tailings reservoir on the coal mining subsidence area as the engineering background. The mechanism of earthquake liquefaction and the risk of catastrophic instability of tailings dam are studied. The research work and the results obtained are as follows: firstly, the complex 3D geological model of the whole tailings dam reservoir area is established by using Midas GTS NX software system, including strata, new and old irregular goaf. Coal seam and future mining plan coal seam: using Visual Studio software to develop interface conversion program, the 3D geological model based on Midas is transformed into FLAC3D system, and a numerical model for stability analysis of large scale tailings dam and foundation is established. Then, according to the ground subsidence monitored in the current stage of tailings dam foundation, the intelligent equivalent rock mass parameter identification model is established by genetic programming and genetic algorithm. The equivalent rock mass mechanics parameters and original rock stress of tailings dam foundation are obtained under the influence of coal mining, which provides reliable rock mass mechanics parameters for the dynamic and dynamic stability analysis and fluid-solid coupling numerical simulation of tailings dam. Thirdly, based on the obtained equivalent rock mass mechanics parameters of tailings dam foundation, the stability analysis of tailings dam in the mining process is carried out under the two working conditions of tailings dam construction and non-dam construction. The results show that the foundation settlement in the tailing reservoir area is significantly affected by mining disturbance. With the coal seam mining year by year, the collapse pit in the south of the reservoir area obviously expands to the west, and the gravity of the dam body after the dam construction intensifies the foundation settlement of the tailings dam, and in 2015, the two collapsing areas of north and south are connected through, and a new collapse pit is formed in the southeast side of the reservoir area. It is estimated that the maximum settlement will reach 4.85 m after 2018, in which the west dam is at risk of instability and is the most dangerous part in the whole reservoir area. Fourth, the dynamic analysis of the effect of earthquake on the stability of tailing reservoir is carried out after the mining of tailing reservoir is finished in 2018. According to the calculation results of the foundation settlement and the acceleration of the dam top, the effect of earthquake on the stability of the tailings dam is not very significant without considering the influence of seepage flow. Finally, the fluid-solid coupling analysis under earthquake action is carried out by using FLAC3D's Finn model, and the liquefaction conditions of tailings dam and foundation are judged on the basis of effective stress. According to the index of super-pore pressure ratio, the soil liquefaction condition is evaluated, and the variation law of initial dam wetting surface under the condition of fluid-solid coupling under dynamic load is obtained. The physical and mechanical indexes, such as stress, displacement, acceleration, pore pressure and super pore pressure ratio, are obtained. The comprehensive analysis and safety evaluation of vibration liquefaction of tailings dam provide scientific basis for optimal design and safe operation management of tailing dam construction in coal mining subsidence area.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD926.4

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