挤密桩预处理后黄土地基灌注桩承载特性

Bearing characteristics of cast-in-place pile in loess foundation after compacted pile pretreatment

为黄土地区城际轨道交通工程建设的安全开展,采用桩基静载试验、孔径测试与数值模拟结合的方法研究黄土地基挤密预处理后灌注桩承载特性.结果表明:黄土地基在挤密桩预处理后,长28.5 m直径1 m的灌注桩单桩极限承载力可达7618 kN.桩基承载性能突出,故在设计当中需考虑该地区挤密桩预处理的地层侧阻力标准值应大于规范建议值;土体挤密系数与桩基承载性状具有相关性,随着挤密系数提高,土层侧摩阻力越大,单桩极限承载力越大,基础沉降越小.研究结果可为挤密桩预处理黄土地基桩基设计提供可靠的依据,对类似工程项目提供参考.

In order to safely carry out intercity rail transit project in loess area,the bearing characteristics of cast-in-place pile after compaction pretreatment of loess foundation are studied by the method of pile foundation static load test,aperture test and numerical simulation.The study shows that the ultimate bearing capacity of a single pile with a length of 28.5 m and a diameter of 1m can reach 7618 kN after the pretreatment of compacted pile in loess foundation.The bearing capacity of pile foundation is outstanding,so it is necessary to consider that the standard value of the lateral resistance after compacted pile pretreatment in this area should be greater than the recommended value of specification.The soil compaction coefficient is related to the bearing capacity of pile foundation,so with the increase of compaction coefficient,the greater the lateral friction of soil layer,the greater the ultimate bearing capacity of single pile and the smaller the foundation settlement.The research results can provide reliable basis for pile foundation design of loess foundation pretreated by compaction pile and reference for similar projects.