巨厚砾岩采场支承压力分布规律实验研究

发布时间：2018-04-23 23:07

本文选题：巨厚砾岩 + 三维模型试验　；参考：《西安科技大学》2017年硕士论文

【摘要】：具有坚硬巨厚顶板、大埋深、厚煤层的采场,其覆岩结构及运动是矿井动载矿压事故的重要影响因素。巨厚砾岩层作为一种特殊的含煤地层结构,由于其结构和力学等特殊性质,使得随着工作面煤层开挖,巨厚砾岩的破断前后支承压力分规律与一般开采环境存在一定的差异性。支承压力往往是采场围岩灾害的主要动力来源,研究巨厚砾岩下采场支承压力分布规律具有重要意义。本文以千秋煤矿巨厚砾岩层地质条件为基础,通过建立适合的支承压力力学模型并对巨厚砾岩层下采场周围支承压力分布规律进行数值计算,同时对光纤在外载荷作用下频移分布规律进行了探究试验,为分布式光纤应用于模型试验煤层底板支承压力测试奠定基础,其次搭建三维模型试验平台,研究采场周围煤岩体支承压力分布规律,并首次提出了分布式传感光纤支承压力测试系统。研究表明,根据关键层理论和关键层破断前后载荷转移特点建立的理论模型,得出倾向支承压力峰值约38 MPa,峰值到煤壁距离约95 m,影响范围约200 m,走向支承压力峰值约51 MPa,峰值到煤壁距离约100 m,影响范围约210 m;通过FLAC3D数值模拟,得出巨厚砾岩层下采场周围走向和倾向支承压力分布规律及塑性区分布特征;对传感光纤进行了标定试验,结果表明外载荷和光纤布里渊频移呈较好的线性关系,拟合系数达到0.952,并首次提出了模型试验传感光纤支承压力测试系统;三维物理相似模型实验中,巨厚砾岩层初次破断和周期破断都伴随着工作面强烈的压力显现,其中下组巨厚砾岩破坏初次破坏距离384m,下组砾岩周期破断距离约为117.3 m,上组砾岩层初次破断距离约为576 m,上组砾岩层周期破断距离约为208 m,下组砾岩层破断是采场周围动力灾害的主要动力来源;分布式光纤支承压力测试系统能够用于模型试验中表征支承压力的变化规律,与压力传感器相比有良好的对应关系,且光纤测试具有高精度、抗干扰能力强等电式传感器不具备的优点,为模型实验支承压力测试提供新思路。
[Abstract]:The overburden structure and movement of stope with hard and thick roof, large buried depth and thick coal seam are the important influencing factors of mine dynamic rock pressure accident. As a kind of special coal-bearing stratum structure, due to its special properties such as structure and mechanics, the supporting pressure law of the super-thick conglomerate before and after breaking is different from that of the general mining environment along with the coal seam excavation in the working face. Bearing pressure is often the main power source of surrounding rock disaster in stope. It is of great significance to study the distribution law of supporting pressure in stope under giant thick conglomerate. Based on the geological conditions of the giant thick conglomerate in Qianqiu coal mine, a suitable supporting pressure mechanical model is established and the distribution of the supporting pressure around the stope under the super thick conglomerate is calculated numerically. At the same time, the distribution law of frequency shift under the external load of optical fiber is studied, which lays a foundation for the application of distributed optical fiber in the test of supporting pressure of coal seam floor, and then builds a three-dimensional model test platform. The distribution of supporting pressure of coal and rock mass around stope is studied, and the distributed sensing fiber supporting pressure measurement system is proposed for the first time. The results show that, according to the theory of critical layer and the characteristics of load transfer before and after breaking of critical layer, The results show that the peak value of inclined abutment pressure is about 38 MPA, the distance from peak to coal wall is about 95 m, the influence range is about 200 m, the peak value of strike bearing pressure is about 51 MPA, the distance between peak value and coal wall is about 100m, and the influence range is about 210m. by FLAC3D numerical simulation, The distribution of supporting pressure and plastic zone around the stope is obtained, and the calibration test of sensing fiber is carried out. The results show that there is a good linear relationship between the external load and Brillouin frequency shift of the fiber. The fitting coefficient is 0.952, and the model test sensor fiber supporting pressure measurement system is put forward for the first time. In the three-dimensional physical similarity model experiment, the initial and periodic breaking of the thick conglomerate bed is accompanied by the strong pressure in the working face. The initial failure distance of the conglomerate in the lower formation is 384m, the breaking distance of the conglomerate cycle is about 117.3 m, the first breaking distance of the upper conglomerate is about 576m, the break distance of the upper conglomerate is about 208m, and the break distance of the lower conglomerate is mining. The main power source of the dynamic disaster around the field; The distributed optical fiber supporting pressure test system can be used to characterize the variation of the supporting pressure in the model test, which has a good correspondence with the pressure sensor, and the optical fiber test has high accuracy. The anti-interference ability of the isoelectric sensor is not good, which provides a new idea for the test of the supporting pressure in the model experiment.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD323

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