直墙拱形巷(隧)道岩爆破坏模式及能量分析

Failure Mode of Rock Burst in Straight-Wall-Top-Arch Roadway( Tunnel) and Its Energy Analysis

针对现有岩爆研究的不足,在物理模拟试验的基础上分析了直墙拱形巷(隧)道岩爆破坏机制及模式,得到了考虑破坏模式的岩爆条件并在此基础上进行了因素敏感性分析。研究表明,根据围岩变形和破坏区被约束程度的不同,岩爆破坏将呈现劈裂破坏、劈裂-剪切破坏和剪切破坏,劈裂-剪切破坏和剪切破坏源于围岩变形的不一致;弯曲应变能是围岩卸荷后由于变形不一致产生的并随着卸荷后载荷的增加而增加,正因为存在变形的不一致才呈现出了不同的破坏形式和爆坑;定义了岩爆危险系数,其值可作为衡量岩爆危险性的度量;高应力区围岩岩爆所需的临界a0(开挖卸荷面爆体中部挠度)是很小的;在a0一定的情况下,劈裂岩爆发生时的破坏区高度范围和深度具有一致的发展趋势;开挖卸荷后的a0值对围岩岩爆的发生与否、强度大小的影响明显。

Aiming at the insufficient of rock burst study,failure mechanism and mode of rockburst in straight wall-top-arch roadway( tunnel) were analyzed based on the physical simulation experiment. Sensitive analysis of factors was conducted considering rockburst condition of failure mode. Research shows that,according to the surrounding rock deformation and the restraint of failure zone,rockburst presents splitting failure,splitting-shear failure and shear failure. Splitting- shear failure and shear failure stem from the difference of surrounding rock deformation. Bending strain energy is caused by the difference of deformation after surrounding rock unloading,and it increases with the increases of load after unloading. Differences in deformation lead to differences in failure modes and pit blasting. Rock burst danger coefficient is defined and its value can be used as a measurement of rock burst risk.The critical a0 value is very small for the unloading rockburst of surrounding rock of high stress zone. Height range and depth of splitting rockburst damage zone have a uniform trend in their development when a0 is a certain value. Value of a0 has obvious influence on the occurrence possibility and strength of rockburst.