地下厂房高应力区节理岩体爆破开挖松动特性研究

为研究地下厂房高应力区岩体在爆破卸荷过程中的松动特征,采用动力松弛与显示计算法分析不同扰动荷载、侧向约束以 及地应力水平等参数对块体位移的影响。 结果表明: 1)在无侧向约束条件下,高应力区节理岩体爆破开挖产生的松动位移主要由 爆破作用产生的能量提供;随着卸荷方向地应力水平的增加,地应力卸荷产生的松动位移与岩体初始储存的弹性应变能成正比。 2)耦合荷载作用下岩块产生的位移为爆破冲击与地应力直接卸荷的非线性叠加,且随着地应力水平的增加,耦合荷载作用对岩块 松动位移有增大效应。 3)在侧向地应力条件下,高应力区岩体爆破开挖松动受侧向母岩的摩擦与吸收爆炸能量作用的影响,其松 动位移显著减小; 随着侧向应力水平的增加,节理松动位移主要由初始地应力储存的能量提供,即原岩应力卸荷产生的松动位移 大于爆破冲击引起的松动位移。

Excavation Loosening Characteristics of Jointed Rock Mass in High Stress Field of Underground Powerhouse under Blasting Load

In order to study the loosening characteristics of jointed rock mass during blasting unloading in high stress area of underground powerhouse, the dynamic relaxation method and display calculation method are adopted to analyze the effects of different disturbance loads, lateral restraints and in-situ stress levels on the displacement of rock mass. The results indicate that: (1) Without lateral restraint, the loosening displacement of jointed rock mass in high stress field is mainly induced by blasting energy; with the increase of in-situ stress level in the direction of unloading, the loosening displacement produced by in-situ stress unloading is proportional to the elastic strain energy stored in the initial rock mass. (2) The displacement of rock mass under the coupling load is a nonlinear superposition of blasting impact and in-situ stress unloading, and with the increase of in-situ stress level, there is augmentation effect on the loosening displacement of rock mass under the coupling load. (3) With lateral restraints, the loosening displacement of rock mass in high stress field is significantly reduced due to the effect of friction and energy absorption of lateral rocks; with the increase of lateral stress level, the loosening displacement of jointed rock mass is mainly induced by the energy of the initial in-situ stress, i.e. the loosening displacement caused by in-situ stress unloading is larger than that caused by blasting impact.