单边扩帮特大跨公路隧道开挖稳定性分析

Stability analysis for large-span highway tunnel by side-expand excavation

通过现场试验、理论分析及数值模拟计算,对深圳横龙山北隧道右线喇叭口扩帮段的围岩力学参数和动态施工力学进行研究,对扩挖修帮段进行深部位移监测得到反挖修帮造成的拱顶下沉和洞周水平收敛的实测数据,并基于神经网络BP模型反演隧道围岩力学参数。采用有限元软件对横龙山北隧道右线喇叭口扩帮段建立三维有限元模型,分析隧道各开挖阶段对地表沉降的影响以及研究隧道各开挖阶段对隧道拱顶、拱脚和竖墙脚各点应力的影响。

The mechanical parameter of the tunnel＇ s surrounding rocks and dynamic construction mechanics were studied by theories analysis, numerical simulation and field measurement in the broadened segment of the right - way bell - mouth of Henglongshan north tunnel in Shenzhen. The deep displacement of surrounding rocks at broadened segment was monitored so as to acquire the numerical value for the settlement of vault and the hori- zontal convergence of the tunnel due to one - sided excavation. Based on the BP model of artificial neural net- work, the mechanical parameter of the tunnel＇ s surrounding rocks was back - analyzed. The finite element soft- ware was used to establish a 3 - D model of the broadened segment of the right - way bell - mouth of Henglongs- han North Tunnel, the effect of each step on the settlement of the earth＇ s surface was analyzed, and the influ- ence of each step on stresses of the tunnel＇s vault, arch foot and basement were studied.