岩溶隧道防突岩层突水模拟分析

Simulation Analysis of Water Inrush in Outburst Prevention Rock Layer of Karst Tunnel

岩溶隧道施工中防突岩层突水已成为我国地下工程建设中的重大问题。本文首先分析了岩溶隧道突水机理和突水类型,然后通过块体离散元分析软件研究了隧道开挖过程中隧道与其边墙外高压富水隐伏溶腔间防突岩层在突水过程中位移场、渗流场的演化特征。研究成果表明:隧道开挖后随着围岩应力逐渐释放,防突岩层经历显著位移、局部垮落和整体破坏3个阶段,最终形成突水通道;开挖初期岩溶水压力分布范围逐渐增大,除防突岩层外其他部位围岩和高压富水溶腔逐步建立了水力联系;开挖后期溶腔水位下降,岩溶水压力分布范围减小。

Water inrush in outburst prevention rock layer of karst tunnel construction has become a major problem in China s underground engineering construction.In this paper the mechanism and types of water inrush in karst tunnels were analyzed firstly then the evolution characteristics of displacement field and seepage field of outburst prevention rock layer between tunnel and concealed karst caverns with high pressure and rich water outside the side wall in the process of water inrush of tunnel excavation were studied by block discrete element analysis software.The research results indicate that after tunnel excavation the stress of surrounding rock gradually releases the outburst prevention rock layer undergoes such three stages as significant displacement local collapse and overall failure and finally forms a water inrush channel.In the early stage of excavation the distribution range of karst water pressure gradually increases the hydraulic connection between surrounding rock of other parts except outburst prevention rock layer and karst caverns with high pressure and rich water was gradually established.The water level of karst cavern decreases and the distribution range of karst water pressure decreases in the later stage of excavation.