钉形水泥土搅拌桩复合地基现场试验研究

Field Test Study on Nail-Shaped Cement-Soil Mixing Pile Composite Foundation

结合浙江省宁波市轨道交通3号线某基地工程实际,对钉形水泥土搅拌桩复合地基承载能力进行了现场试验研究。试验结果表明:钉形水泥土搅拌桩的桩身轴力主要在扩大头处集中;桩身轴力根据桩长的深度逐渐减小;从桩头至桩身变截面处,桩身轴力与桩身变截面以下部分相比,衰减更快;由于钉形双向搅拌桩的桩身结构更为合理,加固效果比传统水泥土搅拌桩更好;且由于钉形水泥土搅拌桩在复合地基应用条件下较传统水泥土搅拌桩的桩间距有增加,故处理相同面积软土地基时所用的总桩数大为减少,可以缩短工期。

Combining with one foundation engineering practice in Ningbo rail transit line Line3,Zhejiang Province,a field test study on the load-bearing capacity of nail-shaped cement-soil mixing pile composite foundation is carried out.The test results show that,the axial force of pile body of nail-shaped cement-soil mixing pile is mainly concentrated at the enlarged head;the axial force of pile body is gradually decreased according to the depth of pile length;from the pile head to the variable cross section of pile body,the axial force of pile body has a faster attenuation than that of the section under the variable section of pile body;due to that the pile body structure of nailshaped bi-directional mixing pile is more rational,the reinforcement effect is better than that of traditional cementsoil mixing pile;compared with the traditional cement-soil mixing pile,the pile spacing of nail-shaped cement-soil mixing pile increases under its application condition in composite foundation,and so the total number of piles used in treating the same area soft soil foundation is greatly reduced which can shorten the construction period accordingly.