南水北调中线磁县段污水管下穿公路顶管施工地表变形规律

顶管施工对地层变形的扰动成为影响周围建筑物安全和环境变化的重要因素之一.以南水北调中线磁县段砂砾石地层中污水管网顶管下穿和谐大道施工为例,对顶管施工扰动下地表沉降变形进行理论预测和现场试验研究,并基于现场实测结果对理论预测模型参数进行了优化修正研究结果表明:当地层体积损失率控制在6.9％以内时,磁县和谐大道附近地表沉降量满足相关规范安全要求;南水北调磁县段污水管网施工范围内地表最大沉降量位于2.5～4 nun,未突破安全阈值;针对类似工况条件提出了地层损失率和沉降槽宽度系数指数建议取值,分别为2.81％和0.425.相关研究成果为类似工况条件下地表变形预测研究提供借鉴.

Research on Surface Deformation Law of Cixian Section of the South-to-North Water Transfer Project

The disturbance of stratum deformation caused by pipe jacking construction has become one of the important factors affecting the safety of municipal engineering and the surrounding environment. We take the construction of the sewage pipe network under the Harmony Avenue in the gravel stratum of the Cixian section of the Middle Route Project of South-to-North Water Diversion as an example. Theoretic prediction and field test research on ground settlement deformation under pipe jacking construction disturbance were carried out. The theoretical prediction model parameters are optimized and revised, which is based on the actual measurement results on site. The results show that: when the formation volume loss rate is controlled within 6.9%, the surface subsidence near Harmony Avenue in Ci County meets the safety requirements of the relevant specifications; the maximum surface subsidence within the construction scope of the sewage pipe network of the Ci County section of the Middle Route Project of South-to-North Water Diversion is between 2.5 and 4 mm, which does not exceed the safety threshold; for similar conditions, the recommended values of ground loss ratio and settlement tank width index are 3.31% and 0.525, respectively. The related research results provide reference for the study of ground deformation prediction under similar conditions.