动力扰动下岩溶隧道突涌水渗流-应力-损伤试验研究

Experimental Study on Seepage-Stress-Damage of Karst Tunnel Gushing Water under Dynamic Disturbance

为探究不同距离下充水溶洞对岩溶隧道突涌水灾变演化的过程,基于扫描电子显微镜(scanning electron microscope,SEM)对研究区的灰岩进行微观结构表征分析,再采用岩石破裂过程分析软件RFPA^(2D)-Flow建立数值模型,模拟不同距离溶洞对隧道开挖的影响。试验结果表明:通过SEM观察发现,灰岩矿物内部晶体颗粒分布不均匀,形状不规则,存在溶蚀孔隙较为发育。隧道在开挖扰动过程中,不同距离下溶洞对隧道围岩破坏过程影响显著,当相对距离为1 m时,溶洞周围围岩单元损伤最严重,2 m时次之,处于临界状态,3 m时最小。整个开挖过程大致可分为3个阶段:压密阶段、裂缝扩展阶段、失稳破坏阶段。根据声发射总能量与声发射计数的趋势变化,可以清晰反映出在隧道突涌水的灾变演化情况。研究成果对富水岩溶隧道突涌水的防预和处治提供给理论指导。

In order to explore the evolution of the flood-filled cavern at different distances to the sudden flood disaster of karst tunnels,the limestone in the study area was analyzed based on scanning electron microscopy(SEM),and then a rock fracture process analysis software RFPA^(2D)-Flow was used to establish a numerical model to simulate the influence of caves at different distances on tunnel excavation.The experimental results show that through SEM observation,it is found that the crystal particles in limestone minerals are unevenly distributed,the shape is irregular,and the dissolution pores are more developed.In the process of excavation disturbance of the tunnel,the cave at different distances has a significant impact on the destruction process of the surrounding rock of the tunnel,when the distance is 1 m,the surrounding rock unit around the cave is the most seriously damaged,followed by 2 m,in a critical state,and the smallest at 3 m.The entire excavation process can be roughly divided into three stages of the compaction stage,the crack expansion stage,and the unstable damage stage.Based on the trend change of the total accumulated energy of acoustic emission and acoustic emission count,the catastrophic evolution of the sudden water in the tunnel can be clearly reflected.The research results provide theoretical guidance for the prevention and treatment of sudden water inrush in water-rich karst tunnels.