高水位软土地区桩基础设计思路和方法
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（北京市建筑设计研究院有限公司， 北京 100045）
［摘要］在高水位地区，由于受到水浮力的影响，桩的受力比较复杂。结合一高水位软土地区的桩基础设计实例，归纳总结出高水位软土地区桩基础设计的思路和方法：桩是抗拔桩还是抗压桩应该根据设计所考虑的各种工况综合判定，桩数的确定应采用多工况包络设计；在正确判定桩受力类型的基础上，桩的配筋应满足其实际受力需要，同时还应满足相应的构造要求。目前，正在被广泛应用的PHC管桩，虽然廉价且施工速度快，但其抵抗水平力的能力很差，在高水位软土地震多发地区应慎重选用。在高水位软土地区选用后压浆钻孔灌注桩并采用桩侧、桩底同时注浆的施工工艺，对大幅提高单桩竖向极限承载力有很好的效果。［关键词］高水位; 软土; 桩基础设计; PHC管桩; 后压浆钻孔灌注桩中图分类号：TU473 文献标识码：A 文章编号：1002-848X(2015)18-0094-07
Ideas and methods of pile foundation design in the area with high water level and soft soilLi Pei, Zhou Sun, Wang Yang, Zhang Yuwei(Beijing Institute of Architectural Design, Beijing 100045, China)Abstract: In the area with high water level, due to the influence of water buoyancy on building, pile force is complicated. With a pile foundation design example in the area with high water level and soft soil, the ideas and methods of pile foundation design in the area with high water level and soft soil were summarized. The pile should be judged as a uplift pile or compression pile according to the various working conditions in design. The determination of the pile quantity should adopt envelope design. Based on correct determination of pile mechanical type, pile reinforcement should meet the actual mechanical needs as well as the requirements of corresponding construction details. At present, prestress high concrete (PHC) piles are being widely used, because of the low cost and easy construction, but the ability to resist the horizontal force is very poor, so the earthquake prone area with high water level and soft soil should be chosen carefully. In addition, the post grouting for cast-in-situ pile grouted on the side and bottom of the pile at the same time could substantially increase the vertical ultimate bearing capacity of single pile in the area with high water level and soft soil.Keywords: high water level; soft soil; pile foundation design; PHC pile; post grouting for cast-in-situ pile
作者简介：李培，硕士，高级工程师，一级注册结构工程师，Email: 1040773008@qq.com。
