复杂工程条件下浅埋矩形大断面顶管关键技术与应用研究

南京地铁3号线新庄站3号出入口通道采用大断面矩形顶管施工技术,在复杂地质及环境条件下施工难度大。顶管施工区段主要处于淤泥质黏土、粉土及冲积-洪积粉细砂地层,地下水丰富且承压水头高,在掘进中易产生排土不畅或造成砂层固结以及顶管进出洞施工风险较高等问题,对周边建(构)筑物及管线保护要求高,交通疏解难度大且管线迁改工期长。通过周密的现场调查研究,在顶管机选型、顶进参数与姿态控制、渣土改良、环境监测等方面采取一系列科学有效的关键技术措施,逐一攻克各个工程技术难点,确保工程的如期贯通。

Key Construction Technical Measures and Effect Analysis of Large Section Rectangular Pipe Pushing under Complex Geologic Conditions

Xinzhuang Station No. 3 entrance / exit passageway of Nanjing Metro Line 3 is constructed by means of large cross section rectangular pipe jacking and the complicated geological and environmental conditions made it very difficult. The pipe jacking construction section is located in silty clay,silt and alluvial-diluvial accumulating sand stratum with rich groundwater and high groundwater pressure,which is likely to hinder dumping or cause sand consolidation during tunneling and lead to high risk during pipe jacking at the entrance / exit of the tunnel. All these call for immediate protection of surrounding buildings,structures and pipelines and make it difficult to maintain normal traffic and result in extended pipeline moving. Through careful and rigorous investigation and analysis,a series of scientific and effective key technical measures are employed in the selection of pipe jacking machine,jacking parameters and posture controlling,sediment improvement,and environmental monitoring and other aspects as well. Furthermore,various engineering problems are solved to ensure project progress schedule.