大断面矩形顶管隧道管节结构优化设计

矩形顶管隧道在城市地下空间的开发和利用中优势明显，但其断面越大，顶管管节设计难度越大，施工风险越高。为解决大矩形断面管节设计的难题，依托郑州市红专路下穿中州大道机动车顶管隧道工程，采用数值模拟、理论分析等方法，对设计中覆土厚度、结构尺寸等关键内容的确定方法进行研究，并介绍管节设计方案、接头和纵向连接设计等要点。研究结果表明： 1）当覆土厚度不小于4 m时，沉降变形基本趋于稳定，最大沉降值为28 mm，沉降值大小安全可控。2）初步拟定断面形式后，需通过结构计算来拟定结构的尺寸，并通过施工阶段和使用阶段的计算验证其合理性。由分析可知，结构厚度初步拟定为600 mm是合理可行的，且无优化空间。3）在确保工程安全的同时，亦需充分考虑工程施工的便捷性和可操作性，需对管节预制方案、管节接头和纵向连接等做出针对性设计。

Optimization Design of Segmental Structure of Large Cross sectionRectangular Pipejacking Tunnel

The rectangular pipe jacking tunnel has obvious advantages in the development and utilization of urban underground space. However, with the increase of cross section of rectangular pipe jacking tunnel, the design difficulty and construction risk increase. By taking the vehicle pipe jacking tunnel project of Hongzhuan Road undercrossing Zhongzhou Avenue in Zhengzhou for example, the numerical simulation and theoretical analysis are adopted to study the determination method of the key contents of rectangular pipe jacking tunnel such as soil cover thickness and structure size in the design. And the scheme of segment design and the design of joint and longitudinal connection are introduced. The research results show that: (1) When the thickness of the overburden is not less than 4 m, the settlement deformation tends to be stable, the maximum settlement is 28 mm and the settlement value is controllable within safe range. (2) After the preliminary formulation of the cross section form, the size of the structure should be determined through the structural calculation, and its rationality should be verified through calculation in construction and operation stages; the analytical results show that it is rational and feasible to initially determine the structural thickness of 600 mm, and there is no optimization space. (3) The convenience and operability of the project construction should be fully considered while ensuring project safety, and the targeted designs for prefabrication scheme of the segment, segment joint and longitudinal connection should be carried out.