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提出采用结构体系可靠度方法研究岩体参数以及荷载等随机性因素对煤层底板抗突水能力的影响.为求出底板抗突水的体系可靠概率,总结了底板的2种不同失效模式:1)底板破坏深度和承压水导升高度之和大于等于底板总厚,即无有效隔水层;2)当底板存在有效隔水层时,有效隔水层强度不足失去承载能力.将这两种失效模式视为串联体系.依据弹性力学固支梁等理论分别建立了2种不同失效模式的功能函数,由Monte Carlo法计算出各单一失效模式以及串联体系的可靠概率,在此基础上分析了随机变量均值、变异系数对可靠概率的影响.研究结果表明,岩体参数以及荷载等随机性因素对底板抗突水能力的影响较大,可同时采用突水系数和可靠概率作为底板突水危险性的评价指标,判定结果将更为准确和全面.
The reliability of the structural system is used to study the influence of rock mass parameters and stochastic factors such as load on the water inrush capacity of coal seam floor.In order to find out the reliable probability of water inrush from the floor, two different failure modes of the floor are summarized: 1 ) The sum of the destruction depth of the bottom plate and the rise of the confined water conductivity is greater than or equal to the total thickness of the bottom plate, that is, there is no effective aquitard; 2) When the bottom plate has an effective aquitard, The failure modes are regarded as a series system.According to the theory of elastic and mechanical beams, two kinds of function functions of different failure modes are established respectively, and the reliability probability of each single failure mode and series system is calculated by Monte Carlo method. On this basis, The results show that the rock mass parameters and random factors such as load have a great influence on the water inrush capacity of the floor, and the water inrush coefficient and reliable probability can be used as the water inrush of floor Risk assessment indicators, the judgment will be more accurate and comprehensive.