泥浆悬浮法机械清孔在桩基施工中的应用

Application of Suspension Slurry Method in the Mechanical Borehole Cleaning in Pile Installation

深圳前海地区地层比较特殊,上部多为大粒径抛石挤淤而成,填石层深厚,下部为第四系海陆交互相沉积层,灌注桩成孔难度较大,为解决在该类特殊性岩土中灌注桩旋挖成孔的施工技术问题,结合某项目案例进行地质条件分析与施工工艺比选,采用旋挖钻机旋挖成孔,利用优质泥浆进行护壁,通过对施工工艺的改进及优化,介绍了优质泥浆的制备及泥浆悬浮法机械清孔工艺及操作要点,并指出施工过程注意事项及施工中可能遇到的问题及处理方法,能有效保障成桩安全、质量、进度及施工效率,且对周边的环境影响较小。

The subsurface conditions in Qianhai area of Shenzhen are special.Because of the reclamation of land in the previous years,the upper part is mostly formed by large-size riprap replacement of the silty soft soils,the rock-filling layer is deep,and the lower part is the Quaternary marine-terrestrial sedimentary layer,which makes the borehole forming of the cast-in-place concrete pile difficult.In order to resolve the construction problem of the rotary excavation of the cast-in-place concrete pile in this special rock and soil strata,a project case history in this area is introduced to analyze the geological conditions and compare the construction method.This paper introduces the preparation of high-quality slurry and the mechanical borehole cleaning method of the suspension slurry method.The major points of the operation through the improvement and optimization of the construction are provided.Key construction procedures,the problems and treatment methods that might be encountered during the construction are also discussed in the paper.These methods are of high practical value,which can effectively ensure the safety,quality,progress and construction efficiency of the pile,and have little impact on the surrounding environment.