复杂地质条件下基坑支护灌注桩施工技术

北京政泉花园工程地质条件复杂，填土层中分布有各种旧管线、旧混凝土基础、混凝土块以及基坑支护留在土层中的土钉和钢绞线等地下障碍物，灌注桩附近有需要进行保护的管线，施工难度大。结合工程实际，采用人工挖孔、长螺旋钻孔后插钢筋笼施工技术。实践表明，该施工工艺能够有效处理浅层地下障碍物和保护地下管线，同时具有施工简单、安全、质量可靠性高，缩短工期等优点，并从根本上排除了泥浆污染和泥浆处理等环保问题，具有明显的经济效益与社会效益。介绍了该施工技术的施工工艺流程、操作要点。

Construction Technology of Cast-in-place Pile of Excavation Support under Complicated Geological Conditions

There were various obstacles distributed in the miscellaneous fill in the site of Beijing Spring Garden project, such as old pipes, old foundation concrete, concrete blocks, the soil nails and steel strands of old foundation pit support, and there were also some pipelines near the piles need to be protected, the construction was very difficult. According to the engineering conditions, artificial hole-digging, drilling with long spiral drilling machine and post-insert reinforced cage were adopted in this project. The practice shows that these technologies can not only effectively deal with the shallow under- ground obstacles and protect the underground pipelines, but also has many advantages of simple and safe construction, high quality reliability and short construction period. The environment problems of slurry pollution and slurry treatment are com-pletely solved with obvious soeial and economic efficiency. The paper introduced these technologies about the construction process and operation points.