爆破荷载诱发节理岩体边坡位移突变的能量机理研究

爆破荷载是水利水电工程岩石边坡开挖主要动力扰动因素之一,在爆破开挖过程中常会出现位移突变。首先根据某节理岩质边坡实测位移数据进行分析,然后结合数值模拟研究了爆破荷载诱发节理岩体边坡位移突变机理及其变化规律,最后探讨爆破设计参数对节理岩体边坡位移突变的影响。研究表明:爆破荷载下,节理岩体的位移突变是由爆破荷载升压阶段岩体的应变能积累突然释放引起的,位移突变量由积聚的应变能密度峰值和应变能密度释放速率共同决定;爆破荷载峰值越大、升压时间越长,积聚的应变能越多;降压时间越短,应变能密度释放速率越快,从而导致突变位移越大。研究结果可为类似边坡工程的爆破开挖安全控制提供参考。

Energy Mechanism of Displacement's Abrupt Change Caused by Blasting Load in Jointed Rock Mass Slopes

Blasting load is a major dynamic disturbance factor of rock slope excavation in water conservancy and hydropower projects. Displacement often changes abruptly in the process of blasting excavation. In association with measured displacement data of a jointed rock slope, we investigated into the mechanism and variation of the abrupt change of displacement of the jointed rock mass slope induced by blasting load via numerical simulation. We also probed into the influence of blasting parameters on the abrupt changes of displacement. Results indicate that the abrupt change of displacement of the jointed rock mass is caused by the sudden release of strain energy accumulated in the rock mass during the boosting load. The amount of displacement's abrupt change is determined by both the peak of accumulated strain energy and the release rate of strain energy. The larger the peak value of blasting load and the longer the boosting time, the more strain energy is accumulated. The shorter the depressurization time, the faster the strain energy release rate would be, resulting in a larger abrupt change of displacement.