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对采空区形成过程中围岩应力路径特征进行分析,并对卸荷荷载进行求解。基于深部开采应力卸荷机制,以程潮铁矿为工程背景,建立深部采空区卸荷失稳分析模型,引入局部能量释放率指标对采空区卸荷过程中能量演化规律进行分析,并基于尖点突变理论建立了围岩失稳局部能量判别准则。研究表明,随着开采的进行,采空区围岩局部能量释放能呈4次多项式增长,增加速率逐渐增加;局部能量突变判别值计算表明,最终采空区系统处在稳定状态,虽然底部结构中的塑性区体积最大,但其对应的单位体积局部能量释放率相对较小,说明相对稳定性较好。局部能量释放率分布云图表明,水平方向上以能量释放为主,垂直方向上以能量集中为主,符合深部开采特征。综上所述,深部卸荷力学模型能有效体现采空区形成过程中围岩的稳定状态,局部能量释放率反应能量释放、转移及耗散等动态过程,为深部采空区稳定性研究提供了重要的参考。
The characteristics of surrounding rock stress path during the formation of goaf are analyzed, and the unloading load is solved. Based on the mechanism of unloading the deep mining stress, taking the Chengchao iron mine as the engineering background, the unloading instability analysis model of the deep gob area is established. By introducing the local energy release rate index, the energy evolution law of the unloading process in the gob area is analyzed. Point catastrophe theory establishes the local energy criterion of rock instability. The results show that as the mining progresses, the local energy release in the surrounding rock of goaf can be quadratic polynomial increase and the rate of increase gradually increases. The calculation of the discriminant value of local energy mutation shows that the final goaf system is in steady state. Although the bottom structure The plastic zone in the largest volume, but the corresponding unit volume of local energy release rate is relatively small, indicating that the relative stability is better. The local energy release rate distribution map shows that energy release is mainly horizontal and energy concentration is mainly vertical, which is in line with the characteristics of deep mining. In summary, the deep unloading mechanical model can effectively reflect the steady state of surrounding rock during the formation of goaf, the dynamic process of energy release, transfer and dissipation of local energy release rate, which can provide the research on the stability of deep goaf An important reference.