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数值模拟已用来确定邻近及远离采场的巷道周围应力的大小和方向。模拟表明邻近采场的巷道处于应力松驰区内。布置在未受回采影响的原岩内的巷道的周边处于受压状态。关键块模拟用于确定关键性块体的代表性形状,离散元模拟用于确定块体的稳定性。模拟结果表明,原岩内巷道的顶板受采矿诱导的应力的作用而稳固。在应力松驰区,关键块会由于开挖而损坏。在邻近及远离采场的巷道中,其两帮关键块会因巷道掘进而损坏。在巷道两帮形成的块体,顶点埋藏浅表面面积大。在较小的巷道内,大多数决定性的关键块体积太大,不会落入巷道,因而不需要支护。可以看出,模拟得出的结论同观测数据一致。这表明关键块理论是所研究的硬岩矿山的巷道稳定性分析的有利工具。随着风险分析法应用于关键块体系,对靠近采空区的巷道的支护作出了明确规定。本方法得出的结果同由经验设计方法得出的支护准则进行了比较。结果表明对于巷道顶板是一致的。然而两帮支护准则就不好比,用风险分析法得出的支护准则同观测数据的吻合程度比经验准则高。在实例分析中提出了极限巷道宽度的概念。一旦巷道宽度大于该极限值,锚杆长度无需随巷道尺寸的增加而加长。可以认为在所有的岩体内情形都是如此。
Numerical simulations have been used to determine the magnitude and direction of stress around the roadway adjacent and away from the stope. The simulation shows that the roadway adjacent to the stope is in the zone of stress relaxation. The perimeter of the roadway arranged in the original rock that is not affected by the mining is under compression. The key block simulation is used to determine the representative shape of the key block, which is used to determine the stability of the block. The simulation results show that the roof of the original rock roadway is stabilized by the stress induced by mining. In stress relaxation zones, the key blocks are damaged by excavation. In the adjacent and away from the stope of roadway, its two key blocks will be due to roadway damage. Two blocks formed in the roadway block, the vertex buried shallow surface area. In smaller tunnels, the bulk of the most critical blocks are too large to fall into the roadway and therefore do not require support. It can be seen that the simulation results are consistent with the observed data. This shows that the key block theory is an advantageous tool for the analysis of roadway stability in hard rock mines studied. With the application of risk analysis to the key block system, the support of the tunnel near the goaf is clearly defined. The results obtained by this method are compared with the supporting criteria derived from empirical design methods. The results show that the top of the roadway is consistent. However, the two support criteria are not comparable, and the risk analysis method is more consistent with the observed data than the empirical criteria. In the case analysis, the concept of the limit lane width is proposed. Once the width of the roadway is greater than this limit, the bolt length does not need to be lengthened as the size of the roadway increases. It can be assumed that this is the case in all the rock mass.