持力岩层起伏较大地区的预制桩施工技术

Construction Technology of Precast Pile in Areas with Large Fluctuation of Holding Rock Strata

以宁波市某医院项目为例,分析了预制桩在持力岩层起伏较大区域项目中应用。结合预制桩的特点,拟采用静钻植桩的施工工艺,但施工中存在钻孔深度判断和现场配桩的技术难点。为此通过试桩确定钻孔电机电流与持力岩层的关系,以电流判断层岩土体;根据持力层标高来确定预制管桩的长度和节数,实行区域分阶段配桩。经检测结果表明桩基各项指标均符合要求。

Taking a hospital project in Ningbo as an example,the application of precast piles in a project with large fluctuation of the holding rock strata was analyzed.According to the characteristics of precast pile,the construction technology of static drilling pile planting was proposed,but there are technical difficulties in the judgment of drilling depth and on-site pile distribution.Therefore,the relationship between the drilling motor current and the holding rock layer was determined by pile test,and the rock and soil mass was judged by the current.According to the elevation of the bearing layer,the length and the number of joints of the precast pipe pile were determined,and the pile distribution was carried out in regional stages.The test results show that all the indexes of pile foundation meet the requirements.