爆炸地冲击扰动诱发含结构面围岩破坏模拟试验

Experimental Simulation of Explosive Impact Disturbance Induced Damage of Surrounding Rock Containing Structural Surfaces

摘要:

为研究远区爆炸作用产生的地冲击扰动对深埋洞室破坏的影响机制，采用地冲击效应模拟试验装置开展了相似模拟试验研究。采用边长为1.3 m的立方体试件，实现了从地应力加载（1 000 m埋深）、洞室开挖到爆炸地冲击扰动加载全过程的模拟。试验过程中，将各类传感器放置在试件和洞室内部，监测试验过程中的应力、应变、位移变化，以及洞室内部的破坏情况。通过在试件顶部施加不同峰值的冲击扰动荷载，再现了碎屑崩出、裂隙连通导致块体崩出、块体滑移和断层激活等破坏现象，初步得到了深埋洞室的安全阈值。分析得到了含裂隙围岩、块系围岩和含断层围岩在不同地冲击扰动作用下的破坏机制。试验结果表明，较小的动力扰动即可诱发深埋洞室的破坏，并且随冲击扰动次数的增加和冲击荷载峰值的增大，洞室破坏程度会加剧；此外，在爆炸远区，地冲击扰动仍可诱发工程灾害。

Abstract:

In order to investigate the mechanism of the effect of ground impact disturbance generated by the blast action in the remote zone on the damage of deeply buried caverns， a similar simulation test was conducted using a ground impact effect simulation test device. A cube specimen with its side length of 1.3 m was used to simulate the entire process from ground stress loading （1 000 m burial depth）， cavern excavation to blast ground impact disturbance loading. During the test， sensors were placed inside the specimen and the cavern to monitor the change of stress， strain， displacement and damage inside the cavern. Damage phenomena such as debris crumbling out， fracture connectivity leading to block crumbling out， block slip and fault activation were reproduced by applying impact disturbance loads with different peak values on top of the specimen. Ultimately， preliminary safety thresholds for deeply buried cavern chambers were obtained. The damage mechanisms of fractured， block and fault-bearing rocks under different ground impact disturbances were obtained. Tests have proven that smaller dynamic disturbances can induce damage in deeply buried cavities. Moreover， the degree of chamber damage increases with the number of impact perturbations and the peak of impact load. The test results demonstrate that ground shock disturbances in the distant area of the explosion can still induce engineering hazards.