顶部隐伏充水溶洞隧道施工阶段围岩稳定性分析

Stability Analysis of Surrounding Rock during Construction Stage of Covered Water-filled Karst Arch Cave Tunnel

结合某岩溶隧道施工过程,利用有限差分软件对顶部存在水压充填溶洞的某隧道围岩稳定性进行数值模拟研究,并将数值计算结果与现场监测结果进行比较分析。结果表明:围岩塑性区主要集中在隧道拱顶、仰拱底、拱腰和溶洞顶部处,溶洞顶部与隧道底部的塑性区有相互连通的趋势。随着隧道接近并通过充水溶洞,拱顶和墙脚两处围岩最大主应力先减小后增大,拱肩处一直增大,拱腰和仰拱底处先增大后减小,主应力最大值位于拱肩区域,其值约为3.0 MPa。

Take a karst cave tunnel as an example,by using the finite-difference software,the stability of surrounding rock of water-filled karst cave in the arch of tunnel is simulated,and the numerical calculation results and field monitoring results are compared.The results show that the surrounding rock plastic zones mainly concentrate on the vault and the invert and arch crown of tunnel and the top of karst cave.The surrounding rock plastic zone of the top of the karst cave and the bottom of the tunnel tends to be connective.With the tunnel close to and through the water-filled cave,the maximum principal stress of surrounding rock of vault and wall-foot first decreases and then increases,the shoulder arch increases continuously,waist arch and the invert arch top increases first and then decreases,the maximum value of principal stress lies in the shoulder arch area,its value is about 3.0 MPa.The obtained conclusions offer a guideline for the design and construction of tunnels in similar underground projects.