【摘要】 基于常被忽略的爆炸荷载对邻近巷道背爆侧围岩缺陷的扰动问题,采用爆炸加载数字激光动态焦散线试验系统,探究了爆炸荷载作用下邻近巷道背爆侧不同倾角裂纹缺陷的扩展规律。试验结果表明:爆炸荷载作用下,直墙拱形巷道背爆侧倾角θ=30o(逆时针方向为正)的预制裂纹最终扩展位移最大,之后随着倾角增大或者减小,裂纹扩展位移均逐渐减小;弧形断面对应力波的削弱作用小于矩形断面,这导致斜向上预制裂纹扩展位移为关于水平方向对称的斜向下裂纹的2~3倍;能量释放率对裂纹的扩展具有驱动效应,且其随时间基本呈现先振荡增加达到峰值,然后振荡减小为零的规律,但这种振荡幅度随裂纹最终扩展位移的减小而变小。上述的研究为邻近巷道背爆侧经济安全合理的支护提供了理论依据。更多还原

【Abstract】 Based on the often neglected problem of disturbance of explosive load to the defects of surrounding rock in adjacent tunnel back-blasting side, using explosion load digital laser dynamic caustics experimental system,the slant crack propagation regularities of neighboring roadway side are explored under explosion dynamic load. The experimental results show that crack extension final displacement is the largest, when the angle of prefabricated crack is in the side of back blasting of the straight wall and arch tunnel is 30° under the blasting load, then with the increasing or decreasing of crack angle, the ultimate displacements of crack extension all tend to decrease gradually; attenuated effect for stress wave of arc is less than the rectangle. Consequently, oblique upward crack extension displacement is 2-3 times of oblique down crack which is symmetry with horizontal subjected to blasting loading. In addition, energy release rate has driving effect on the propagation of the crack, and the energy release rate reaches the maximum in a moment and then gradually decreases to zero. But this change range becomes small with the crack extension displacement decreasing. The research provides theory basis for the economic and reasonable supporting of adjacent tunnel back-blasting side.更多还原