锚杆支护煤巷稳定性可靠度分析

RELIABILITY ANALYSIS OF STABILITY OF COAL ROADWAY SUPPORTED BY ROCK-BOLT

有些锚杆支护的煤巷曾发生过严重的冒顶,事故原因很复杂。其中煤巷支护设计与分析存在的问题有两个方面:一是煤巷围岩的物理、力学参数存在不确定性;二是稳定性设计分析的力学模型很多,各自只能从一个侧面反映其力学机理。为了对安全系数进行补充,考虑设计中的随机因素,在分析这些不确定性因素的基础上,根据巷道地压理论中的散体模型,锚杆支护结构抗力原理,研究了煤巷锚杆支护围岩稳定可靠度分析中抗力和荷载的计算方法,分析了某一锚杆支护煤巷的稳定可靠度,并认为锚杆支护的煤巷破坏失效概率在10%左右是可以接受的。

Mechanism of some serions rock caving cases in rock bolted coal roadway is very complex. There are mainly two reasons:the one is the uncertainty of physical parameters and mechanical characteristics of surrounding-rock,and the other is that various calculation models used for analyzing the stability of surrounding-rock in roadway only partly reflect the mechanical behaviors of surrounding-rock. To improve design approach based on safety coefficient and to consider stochastic factors as mentioned above,based on a model of loose weight for rock-mass of underground pressure theory and a principle of resistance force development in structure supported by rock-bolt,the paper researched calculation methods of resistance force and load in limite state equation which was used to calculated stability degree of surrounding-rock in coal supported by rock-bolt. A stability reliability degree for surrounding-rock of a underground roadway in coal supported by rock-bolt has been calculated,and the conclusion is that failure probability about l0 percent of surrounding-rock in a rock-bolt supported coal roadway is acceptable.