湿陷性黄土场地孔内深层超强夯挤密桩试验研究

Study on the Super Down Hole Deep Compaction in Collapsible Loess Site

为消除黄土地基湿陷性并提高承载力,常用挤密桩法处理黄土地基,孔内深层超强夯挤密桩是对孔内深层强夯挤密桩的发展。本文结合西安田家湾粮库湿陷性黄土地基处理项目,对桩身填料灰土和渣土的孔内深层超强夯挤密桩进行试验,对两种填料的挤密桩承载力、挤密系数、湿陷性等进行研究。结果表明,两种填料挤密桩均能消除黄土湿陷性,灰土挤密桩处理效果优于渣土挤密桩,渣土挤密桩桩身挤密系数离散性较大。桩间土的承载能力均得到很大改善,并提高了桩间土承载力和复合地基承载力,灰土挤密桩桩体承载力平均值约为渣土桩的2倍,桩间土平均承载能力为处理前1.6倍,不同桩身填料对桩间土承载力影响不明显。

The Compaction Pile Method is usually used to eliminate the collapsibility of loess foundation and enhance the bearing capacity.Super Down Hole Deep Compaction is the development of Down Hole Deep Compaction.Based on the tests to the collapsible loess foundation treatment project of Xi’an Tianjiawan grain depot,the experiment is carried out on Super Down Hole Deep Compaction pile filled with lime and residual soil,and the bearing capacity,compaction coefficient,collapsibility of lime and residual soil compaction pile are analyzed.The results show that the loess collapsibility can be eliminated by compaction pile of both fillings,the treatment effect of lime-soil compaction pile is superior to residual soil,and the latter compaction coefficient along pile is more discrete.The bearing capacity of soil between piles is greatly improved,and soil bearing capacity between the pile and composite foundation bearing capacity is also improved.The average bearing capacity of lime-soil compaction pile is about 2 times that of residual-soil pile and 1.6 times that of inter-pile soil before treatment.Both fillings have little influence on the bearing capacity of the inter-pile soils.