Stability Analysis of Rock Pillar between Tunnel and Large-Scale Concealed Cave on Top of Tunnel

Accompanying the enforcement of strategy to develop western regions, transport and other infrastructures of western China expand substantially and long tunnel in karst zones increases dramatically. Geological hazard of water inrush and mud outburst often occur in the process of karst tunnel construction, which often lead to equipment destroyed and construction period bungled, even serious casualty and economic loss. The influence of large-scale concealed caverns with high pressurized water on top of tunnel on the stability of rock pillar between them is researched in this paper. According to the actual conditions, rock pillar is simplified into beam with both ends built-in. Utilizing the conception of classic structural mechanics, a model is developed to calculate the minimum thickness of rock pillar in order to evaluate its stability by use of the criteria of shear strength and tensile strength of rock pillar. As a example, the proposed model is applied to predict the stability of rock pillar between karst tunnel on Yi-wan rail line and concealed cave with high pressurized water, the result illuminates that this methods is feasible to supply basis for evaluating the stability of rock pillar during construction period of karst tunnel.