大断面隧道密贴下穿既有隧道沉降控制体系研究

Study on settlement control system of the large section tunnel with closely adjacent down-traversing the existing tunnel

大断面隧道密贴下穿既有线工程施工难度大、沉降控制严格,是穿越工程中重点研究的对象。以某城市新建穿越工程为背景,通过试验分析、数值计算与现场监测相互验证的方法,研究了'超前深孔注浆+六导洞PBA+边桩顶升'沉降控制体系下的既有隧道沉降规律,现场监测表明隧道沉降和变形缝差异沉降均达到良好的控制效果,保证了施工安全和既有隧道的运营安全。此研究成果可为类似下穿工程提供借鉴。

The crossing project of large section tunnel with closely adjacent down-traversing the existing tunnel is the important research object in the crossing project,owing to difficult construction and rigorous settlement. In the background of a new crossing project in a city,the settlement law of the existing tunnel about"advanced deep hole grouting + PBA of six pilot holes + side pile jacking"settlement control system was studied by experimental analysis,numerical calculation and field monitoring. The field monitoring shows that the settlement of the tunnel and the differential settlement of the deformation seam all achieve good control effect and it guarantees the safety of construction and the normal operation of existing tunnel. The research results can provide reference for similar crossing engineering.