煤矿回采巷道底臌变形分析及其破裂过程模拟.doc

煤矿回采巷道底臌变形分析及其破裂过程模拟 李常文 （中国煤炭科工集团沈阳设计研究院 沈阳） 摘 要：巷道底臌发生机理一直是煤矿开采中各类巷道中最难解决的问题。本文建立了巷道围岩变形的力学模型，基于软岩的膨胀理论与层状底板的应力状态，分析软岩回采巷道底臌发生过程，计算膨胀引起的底臌量。为进一步分析软岩巷道底臌过程，考虑软岩的蠕变特性及非均质性。在岩石破裂过程分析系统（RFPA）的数值模型中，引入蠕变模型及非均质系数，对软岩巷道的变形和底臌破裂过程进行数值模拟。从数值模拟结果中可以看出，在水平恒定荷载及岩体蠕变作用下，巷道围岩的应力集中造成巷道底板岩层的初始破坏，底板岩层出现初始离层；垂向荷载下降，导致巷道底板出现破裂并发生扩展，加快巷道底板岩层向巷道内移动速度，致使底板发生离层；随着时间的变化，底板岩层的强度值不断衰减，造成巷道底板岩层不断向巷道内鼓出，产生挤压流动性底臌。 关键词：软岩，底臌，蠕变，非均质性，RFPA2D The deformation mechanism analyzing and failure process modelling of floor heave at the coal stoping tunnel Li Changwen () Abstract: It is difficult to analyze the mechanism of floor heave in the roadway of underground coal mine. In this paper, the deformation mechanics model of surrounding rock has been set up. Based on the swelling mechanism of soft rock and stress condition of floor strata, the deformation process of floor heave has been analyzed, and the displacement of floor deformation has been calculated. In order to analyze the process of floor heave of soft rock, the creep properties and inhomogeneity coefficient has been considered in the RFPA2D model, which is helpful to analyze the deformation and floor heave process. From the numerical result, floor strata failure and initial strata separation of floor strata was presented under high horizontal stress condition; with the vertical stress reducing, floor strata appeared the failure and propagation, which accelerated the floor strata moving to roadway and lead to floor strata separation. With time changing, the strength of floor strata continued to attenuate, and the floor strata heaved to roadway continually and emerged the squeezing and fluidity of floor heave. Keywords: numerical simulation, floor heave, creep deformation, failure mode, soft rock; 1前 言 软岩问题从20世纪60年代就作为世界性难题被提了出来，特别是煤矿软岩问题一直是困扰煤矿生产和建设的重大难题之一。大变形、难支护的破坏特征，随着煤矿开采深度的增加，一些矿山巷道越来越引起采矿工作者和岩石力学工作者的普遍关注。近年来，国内外很多Aafrouz 和Chugh et al. [－]总结了形成巷道底臌的21个因素，其中造成巷道底臌的最主要的三个因素是：巷道底板为软岩层；巷道围岩的高应力和地下水的影响；Gesell [8]认为底臌是底板泥岩遇水膨胀的结果；何满朝