湘江排水口整治工程设计的顶管施工是在粉质粘土为主的地层中进行,为确保施工和周围建筑物的安全,须采用泥水平衡理论,严格控制管道周围的土体扰动和地表产生大变形.而实际施工到W13-W15井位之间D1800顶管全部位于砂卵石地层中,在施工过程中监测到地表最大沉降量达到457.4 mm,部分地段已经冒顶地表出现塌陷.结合地层重新勘探结果,对施工引起的地表变形机理和原因等进行了总结分析.并提出了在顶管两侧设计止水帷幕、区段中间注浆加固并回填的处治措施,同时在W13-W15顶管区间新增一个工作井缩短顶管距离.在后续顶管施工过程中对地表沉降进行监测,结果表明地表沉降在可控制范围内,确保了施工和周围环境的安全.
Xiangjiang remediation drain pipe jacking construction engineering design is carried out mainly in silty clay stratum, in order to ensure the safety of the construction and the surrounding structures, the water balance theory must be used to strictly control the disturbance of soil around the pipe and the large deformation of the ground surface. While the actual construction between W13 to W15, D1800 pipe were all located in sandy pebble stratum, during the construction process monitoring to the maximum ground settlement reached 457.4 mm, some sections had roof fallen and surface collapse had occurred. The mechanism and causes of surface deformation caused by the construction were summarized and analyzed . And some treatment measures were put forward, such as in the pipe on both sides to design waterproof curtain, to use grouting and backfill in the middle section , at the same time, in the interval of W13 ~W15 add a new working well to shorten the distance of pipe jacking. The ground subsidence was monitored during process of subsequent pipe jacking construction, the results show that the surface subsidence is controlled within the control range, ensures that the safety of construction and surrounding environment.