无掩护海域复杂地质条件下的灌注桩施工

Construction of bored pile under complicated geological conditions in unshielded sea area

桩基础的施工是高桩墩台结构施工的关键,尤其是在无掩护海域、无覆盖层复杂地质条件下的灌注桩施工,影响因素多、技术难度高。结合巴基斯坦某电厂码头引桥灌注桩施工的实际情况,从施工条件、关键施工工艺等环节展开分析。结果表明:针对无覆盖层地质下的钻孔灌注桩施工,钢护筒施工建议采用打钻结合、复打二次跟进的施工工艺;为保证桩基垂直度,施工中需针对具体桩基情况设计相应的打桩导向架;水下钻孔灌注施工过程中如遇异常问题,应立即暂停施工,提出针对性的解决方案后方可继续施工。

The construction of pile foundation is the key to the construction of high pile supported dolphin structure,especially the construction of bored pile under complicated geological conditions in unshielded sea area due to many influencing factors and high technical difficulty.Based on the actual construction situation of bored pile for wharf approach bridge of a power plant in Pakistan,the construction conditions and key construction techniques are analyzed.The analysis results show that:for bored pile construction without overburden geology,steel casing construction is suggested to adopt the construction technology of combination of drilling and re- drilling;in order to ensure the perpendicularity of pile foundation,the corresponding piling guide frame should be designed according to the specific pile foundation conditions;in the process of underwater bored pile construction,if abnormal questions occur,construction should be suspended immediately and specific solutions needed to be put forward before continuing construction.