岩爆孕育和发生全过程数值研究

Numerical study of gestation and occurring of rockburst

岩爆与地震、高速滑坡以及冲击地压等都属于岩石动力灾害.按照多尺度力学的观点,它们有相同的发生机制,即损伤演化诱致灾变.岩爆是工程尺度的灾变,是材料微损伤成核、生长和贯通等演化的结果.利用FEM数值方法,通过隧道断面损伤斑图的生长过程模拟工程灾变的演化过程.结果显示,岩爆区与炸药爆破坑具有相同的形状,岩爆的冲击性来自应变能的突然、集中地释放.岩爆事件可以分为2个阶段:第一阶段是岩爆体从母岩中被"V"形的软弱损伤带分划出来;第二阶段是岩爆楔形体内应变能的释放阶段.岩爆的监测、防治措施必须在第二阶段开始前完成.

Rock burst, earthquakes, rapid land sliding and gas etc. belong to dynamical disasters. According to the idea of multi - scale mechanics, the occurrence mechanism is same for damage evolution inducing catastrophe. Rock burst is the catastrophe on the scale of engineering structures such as a tunnel cross - section, which is the result of dynamic evolution of the rock engineering structures in which the micro damages nucleate, grow up and run - through. This paper simulates the growth of damage pattern based on a tunnel cross section with the numeric method of FEM. The result shows that the zone of rock burst has the same geometry as a blasting crater with explosive. The impact of rock burst originates from the abrupt and concentrated release of elastic strain energy. The occurrence of rock burst can be divided into two stages： The first stage is the zoning of rock burst from the mother rock by the ＂ V＂ shape damage bands. The second stage is the relatively slow accumulation and rapid release of elastic strain energy in the wedged -shape body. The rock burst monitoring, prevention and treatment must be taken before the second stage.