湿陷性黄土地区后注浆灌注桩承载特性研究

Study on Bearing Characteristics of Post-grouting Pile in Collapsible Loess Area

文中以某住宅建筑为例,对湿陷性黄土地区传统灌注桩与桩尖区域后注浆加固灌注桩在受到设计负荷影响时,其轴向力与侧向摩擦力的差异进行分析。结果表明,在特定湿陷性黄土环境中,采用干式作业方式完成的钻孔灌注桩承载能力得到显著提升,桩体的中性点位置亦显著下移;湿陷性黄土地区的现场浸水试验与室内试验的湿陷量差异较大,建议通过现场浸水试验确定实际的湿陷量,进一步明确土壤湿陷等级,为地基设计提供准确数据。

In this paper,taking a residential building as an example,the differences of axial force and lateral friction between traditional cast-in-place pile and post-grouting reinforced cast-in-place pile in collapsible loess area under the influence of design load were analyzed.The results show that in a specific collapsible loess environment,the load carrying capacity of the bored pile completed by dry operation is signif-cantly increased,and the neutral point of the pile is also significantly moved down.There is a great difference between the field immersion test and the laboratory test in collapsible loess area.It is suggested that the field immersion test should be used to determine the actual collapsible amount and further determine the grade of soil collapsibility,so as to provide accurate data for foundation design.