富水砂层大直径长距离顶管施工技术研究

Study on Construction Technology of Large-diameter Long-distance Pipe Jacking in Water-rich Sand Layer

摘要:

富水砂层条件下大直径长距离顶管施工，存在顶进摩阻大、姿态不易保持、地层沉降变形不易控制等问题。针对这三项难题，进行顶管关键技术研究，提出了注浆减摩、实时监测等多项技术相结合的方法；并依托哈尔滨阿什河穿河段污水主干线工程，采用MIDAS GTS NX有限元软件，对顶管动态顶进施工过程进行了三维有限元数值模拟，并对周边环境的影响进行评估。结果表明：顶管施工过程中，施工段最大水平位移量为2.11 mm，最大竖向位移量为3.74 mm，阿什河受2号~3号顶管段施工引起的最大水平位移量达到0.73 mm；最大竖向沉降量达到2.38 mm；既有堤坝受4号~3号顶管段施工引起的最大水平位移量为0.67 mm，最大竖向沉降量为1.89 mm。

Abstract:

In the construction of large-diameter long-distance pipe jacking under the condition of water-rich sand layer， there are problems such as large jacking friction， attitude hard to maintain， and stratum settlement deformation not easy to control. Aiming at these three problems， the key technology of pipe jacking is studied， and the method of combining grouting friction reduction， real-time monitoring and other technologies is put forward. Based on the sewage trunk line project crossing the Ashi River in Harbin， the three-dimensional finite element numerical simulation is carried out for the dynamic jacking construction process of the pipe jacking by using MIDAS GTS NX finite element software， and the influence on the surrounding environment is evaluated. The results show that in the process of pipe jacking construction， the maximum horizontal displacement of the construction section is 2.11 mm， the maximum vertical displacement is 3.74 mm， and the maximum horizontal displacement of Ashi River caused by the construction of No.2 ~ No.3 pipe jacking section reaches 0.73 mm. The maximum vertical settlement reaches 2.38 mm. The maximum horizontal displacement of the existing dam caused by the construction of the No.4 ~ No.3 pipe jacking section is 0.67 mm， and the maximum vertical settlement is 1.89mm.