基于爆破损伤隧道初支与掌子面合理距离研究

基于钻爆法，研究在围岩损伤条件下初期支护滞后掌子面不同距离时隧道稳定性。利用声波检测隧道爆破开挖后围岩的扰动损伤，将隧道支护时机与施工时初期支护滞后掌子面距离相结合，通过FLAC3D数值模拟分析不同初支滞后距离下围岩的位移量、应力大小，得到在该工程地质条件下，随着距离的增加，围岩位移量略有增加，围岩应力降低，并最终趋于稳定，根据其变化规律分析可得初期支护滞后掌子面12 m的情况下围岩能够自稳。实践证明，不仅取得了良好的光面爆破效果，而且有效地控制住围岩超欠挖，从而取得较大的经济效益。

Study on the Reasonable Distance between Primary Support and Tunnel Face Based on the Damage of the Rock Mass

The stability of tunnel has been studied based on damage of the surrounding rock mass with the proper distance between the tunnel face and the primary support using borehole-blasting method. The disturbance damage of surrounding rock after blasting excavation of tunnel is detected by acoustic wave. The proper distance between primary support and tunnel face has been combined with reasonable support time. Through the FLAC3D numerical simulation, the displacement and stress of the surrounding rock with different distance between the tunnel face and the primary support has been studied, which revealed that the displacement of the surrounding rock will increase and the stress will decrease with the increase of distance between the tunnel face and the primary support and finally tend to stable. The value of the displacement and stress can be used to analysis the stability of the tunnel. When the distance between primary support and tunnel face increased to 12 meters, the tunnel will be stable. It is proved that the good smooth blasting effect has been obtained and the overbreak of surrounding rock has been controlled effectively, reaching a better blasting result and economic benefits.