夯实水泥土桩复合地基中桩-土-垫层共同作用机理

Bearing behavior of column-soil-cushion mutual action in composite foundation with rammed cement-soil column

基于剪切位移法,引入Mylonakis&Gazetas桩-土相互作用及温克尔地基模型,导出复合地基中桩-桩、桩-土及土-土相互作用柔度系数计算式;在此基础上,考虑垫层的影响,提出路堤荷载作用下桩-土-垫层共同作用分析的新方法,并利用Matlab软件编制相应的计算程序。以夯实水泥土桩复合地基为例,进行路堤荷载下夯实水泥土桩复合地基的室内模型试验,探讨垫层模量及厚度对桩与土差异沉降的影响。研究结果表明:在路堤荷载作用下,设置合适的柔性垫层,能有效增加桩体承担荷载的比例,发挥桩的承载能力,减少桩与桩间土之间的差异沉降及复合地基的沉降,改善复合地基的工作性状。

Based on the shear displacement method and the Mylonakis ＆ Gazetas model for interaction between pile and soil,and the Winkler’s layered foundation model was introduced,the calculation formulae of the flexibility coefficients for interaction between pile and pile,pile and soil,soil and soil were obtained.Considering the performance of cushion,a new analysis method on pile-soil-cushion mutual action under the embankment was suggested,and the correlated program was developed by Matlab software.Taking the composite foundation with the rammed soil-cement columns as an example,the model test of the composite foundation with the rammed soil-cement columns was performed under the embankment,the influences of the cushion modulus and thickness on the differential settlement between column and soil were discussed.The results show that under embankment load,column may play a better role,and the load sharing of soil surrounding columns and differentia settlement among columns and soils may be reduced to improve the working properties of composite foundation by setting the appropriate soft cushion.