大断面浅埋隧道管棚支护参数优化研究

Research on Optimization of Supporting Parameters of Pipe Shed in Large-section Shallow Tunnel

为研究浅埋隧道管棚超前支护参数对隧道支护效果的影响,利用有限差分法软件Flac3D对重庆东环线白杨湾下穿高速公路隧道进行建模。并将计算结果与实测结果进行对比,验证模型正确性,然后通过改变管棚直径、管棚间距、布置角度等参数,进行多种工况数值仿真模拟,分析了管棚参数对地表沉降控制效果的影响。结果表明:增大管棚直径可以减小地表沉降,管棚最佳直径为150~200 mm;当管棚间距大于0.4 m时,地表沉降迅速增加;管棚的最佳布置角度为120°~130°,当超过此范围时继续增加布置角度对沉降控制效果不明显。

In order to study the influence of pipe shed advance support parameters on the supporting effect of the tunnel,the finite difference method software Flac3D is used to model the tunnel under the Baiyangwan expressway of Chongqing East Ring Road.The calculated results are compared with the measured results to verify the correctness of the model.Then,by changing the parameters such as the diameter of the pipe shed,the distance between the pipe shed and the layout Angle,the numerical simulation of various working conditions is carried out,and the influence of the pipe shed parameters on the control effect of the surface settlement is analyzed.The results show that the surface settlement can be reduced by increasing the diameter of the pipe shed,and the optimal diameter of the pipe shed is 150-200 mm.When the distance between the pipe shed is greater than 0.4 m,the surface settlement increases rapidly.The optimal layout Angle of the pipe shed is 120°-130°,and the settlement control effect is not obvious if the layout Angle continues to increase beyond this range.