露天-地下联合开采保安矿柱稳定性

Stability of safety pillars in opencast-underground combined mining

通过对矿柱力学模型的分析,得到不考虑平面应变问题的矿柱厚度计算公式,对回采前后矿柱的受力形态及破坏模式进行分析。利用统计学原理计算矿柱厚度影响因素(跨度、容重、强度、动载荷等)的变异系数,并进行权重分析,利用FLAC3D进行了矿柱厚度三维数值模拟,研究矿柱厚度为15,20和25 m时的最大主应力分布、剪应变率变化规律、矿柱沉降规律和塑性区分布规律,同时利用FISH语言编写安全系数计算程序。研究结果表明:贵州某矿保安矿柱厚度在20 m左右时既能满足稳定性要求又能兼顾有效回采的目的。

The mechanical properties of the safety pillars were analyzed to obtain a thickness formula without consideration of the plane strain. This formula was then used to analyze the stress state and failure mode of the pillars before and after robbing. Using the principle of statistics, the variable coefficients of pillar thickness influence factors （span, unit weight, strength and dynamic load and so on） were calculated and the weight of each factor was compared, Besides, the numerical modeling of the pillar thickness was conducted using FLAC3D, with which the maximum principal stress distributions, shear strain rate varying patterns, pillar subsidence rules and plastic zone distributions with the thickness of 15, 20 and 25 m respectively were figured out. The procedure of how to calculate the security coefficients was written with the FISH language. The results show that when the pillar thickness is about 20 m, both stability and efficient robbing can be achieved.