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矿山开采对采动影响区域内的围岩形成扰动,弱化岩体力学性质,其参数劣化规律是数值模拟与分析计算的主要问题之一。以铜坑矿92#矿体连续采矿顶板诱导崩落试验采场为对象,运用卸荷岩体力学理论,确立了开挖卸荷岩体力学参数计算模拟的计算流程。结合有限元数值模拟方法,建立了岩体卸荷等效模型,进行了6步连续卸荷的计算,得到了地下连续采矿顶板卸荷岩体力学参数的变化规律,并运用多项式实现了卸荷岩体力学参数与卸荷量变化值的函数拟合,获得了采动卸荷岩体力学参数的劣化规律。结果显示,卸荷第6步时,计算不收敛,表明此时顶板已经完全破坏而发生崩落;在卸荷过程中,岩体力学参数均呈逐渐弱化的趋势,其中内摩擦角、凝聚力和弹性模量随开挖卸荷的推进呈逐渐减小的趋势,最终的参数分别相当于初始值的55%、50%和50%,但泊松比呈逐渐增大的趋势,最终值相当于初始值的1.15倍。其结果说明了采动卸荷导致了岩体质量的劣化,卸荷岩体力学参数与卸荷量的函数为采动卸荷力学响应的动态分析提供了理论基础。
Mining is disturbing the formation of surrounding rock in mining area and weakening the mechanical properties of rock mass. The deterioration of parameters is one of the main problems in numerical simulation and analysis. Based on the mechanics theory of unloading rock mass, the computational process of the calculation of mechanical parameters for unloading rock mass is established. Based on the finite element numerical simulation method, an equivalent model of rock mass unloading was established and the calculation of 6-step unloading was carried out. The variation of mechanical parameters of unloading rock mass under continuous underground mining was obtained, and the unloading The function of mechanical parameters of rock mass and unloading quantity is fitted as a function to obtain the law of deterioration of mechanical parameters of unloading rock mass. The results show that the calculation does not converge when the sixth step is unloaded, which indicates that the roof has been completely destroyed and collapsed during the unloading process. During unloading, the mechanical parameters of the rock mass gradually weakened. The internal friction angle, cohesion and elasticity The modulus tends to decrease with the excavation and unloading propulsion. The final parameters correspond to 55%, 50% and 50% of the initial value respectively. However, the Poisson’s ratio shows a gradual increasing trend, and the final value is equivalent to the initial 1.15 times the value. The results show that the mining unloading leads to the deterioration of the rock quality. The function of the unloading rock mass mechanical parameters and the unloading quantity provides a theoretical basis for the dynamic analysis of the unloading dynamic response.