上海长江隧桥工程环境地质问题与技术对策

Environmental geological problems and technological countermeasure for Shanghai tunnel-bridge engineering across Changjiang River

上海长江隧桥工程横跨长江河口,所在区域复杂的水文、地质条件易对工程施工带来不利影响。本文分析了软土变形、水土突涌、水下砂体运移、浅层天然气、岸带冲淤、砂土液化、地面沉降等环境地质问题及其潜在的工程危害,评估了工程的地质安全性,提出了相应的防治技术措施与对策建议。工程的陆域段地质安全性高、水域桥梁段中等、水域隧道段相对较低,采用成熟稳妥的施工工艺和方法可有效避免和减弱工程诱发或加剧的地质灾害。

Shanghai tunnel-bridge engineering across Changjiang River is a national important basic construction project in estuarine of Changjiang River. It adopts tunnel with bridge and double layers for expressway in upside and rail in underside. It is supreme tunnel-bridge engineering in the world at present. On a field basis of hydrologic and geological condition along the construction line, this paper expatiated on the environmental geological problems as soft soil deformation, water and soil piping, movement of sand under water, danger of shallow natural gas, beach erosion and deposition, sand liquefaction and land subsidence, analyzed on the potential harm for engineering, evaluated the geological safety for this project, and advanced corresponding prevention countermeasure and technological measure. The geological condition is much safer in land section of engineering, common safe in bridge section and less safe in tunnel section. It can effectively avoid and reduce danger of works induced or aggravated by geological hazard using mature construction craft and methodology.