真空预压软基处理法在深基坑支护工程中的应用

Application of the Vacuum Preloading Soft Soil Treatment in Deep Foundation Pit Supporting

软弱地基上的深基坑开挖一直是基础工程的重难点,关系到边坡稳定、基坑支护成本、桩基的安全等问题。中山港口某项目,占地面积5.3万m2,基坑深约4 m,地处深厚淤泥之上,如何保证基坑开挖以及工程桩的安全成为重难点。经70余天的真空预压处理,场地沉降约1 m,基底上下5 m范围内的淤泥固结成了软塑状的淤泥质土,其承载力等力学性能得到很大提高,使基坑支护工程和土方开挖的难度大大降低。文章以该项目深基坑支护工程为背景,详细论述了真空预压软基处理方法的施工工艺、处理效果以及施工注意事项,其在深基坑支护工程中的成功运用可供类似工程参考。

Deep foundation pits on soft soil had been a difficult foundation work, which was related to the slope stability, cost of excavation and pile safety. The engineering project in Zhongshan Port covered an area of 53 000 m2, and the pit was about 4 m deep. The project was located on deep silt, thus ensuring the safety of excavation and pile became an important and difficult problem. After 70 d of vacuum preloading, the site settlement was about 1 m, and the silt within 5 m above and below the basement was consolidated and turned into soft-plastic silty soil. The bearing capacity was greatly improved, and the difficulty of foundation pit supporting and excavation was reduced. Based on the foundation pit supporting of this project ,this paper discussed the construction technique, treatment effect and matters to be noted in this soft soil treatment. This successful experiment of deep foundation pits project can provide valuable reference for similar projects.