橡胶轮胎散体桩群桩复合地基有限元分析

Finite Element Analysis on Composite Foundation with Rubber Tires Granular Pile

目的分析橡胶轮胎散体材料桩(RGP)群桩的承载性能,为橡胶轮胎散体桩复合地基的实际应用提供设计参数.方法通过ABAQUS有限元软件建立桩土三维有限元模型,研究不同桩长、桩径、桩间距及褥垫层厚度等对橡胶轮胎散体桩群桩承载性能的影响,得到载荷-位移、桩身应力等关系曲线.结果 RGP桩复合地基的沉降随桩长的增加而减小,但存在有效桩长.随着桩间距的增加,RGP桩复合地基的承载力、桩顶应力和桩身最大应力增加,桩土应力比先增大后减小.随着桩径的增加和褥垫层厚度的增加,RGP桩复合地基的承载力均呈增加趋势,桩土应力比减小.桩径的增加在提高复合地基置换率的同时也使得橡胶轮胎的环箍能力降低,所以RGP桩复合地基设计时应综合考虑桩土承载能力和橡胶轮胎的环箍作用.结论合理调节桩长、桩径、桩间距、褥垫层厚度等参数会促进桩土协同作用的发挥,进而改善RGP桩复合地基的承载能力.

Analysis of bearing capacity of composite foundation with rubber tires granular piles （RGP for short）can provide references for the practical application of RGP composite foundation. Soil and pile three-dimensional finite element model was established by ABAQUS finite element software. The model can be used to calculate and analyze the effect of different pile length, pile di- ameter, pile spacing and cushion thickness on RGP composite foundation. Load-displacement curve and pile stress was obtained. The settlement of RGP pile composite foundation decreases with the increase of pile length, but there is an effective pile length. With the increase of pile spacing, the bearing capacity, the stress of pile top and the maximum stress of RGP pile composite foundation increase, and the pile-soil stress ratio increases first and then decreases. With the increasing of pile diameter and the cushion thickness,bearing capacity of RGP pile composite foundation increases, the pile-soil stress ratio decreases. Due to the increase of the pile diameter, the replacement rate of the composite foundation is improved, and the hoop capacity of the rubber tire is reduced, the effect of hoop and bearing capacity should be considered in RGP composite foundation designs. A reasonable adjustment pile length ,pile diameter ,pile spacing, cushion thickness and other parame- ters will promote synergies of pile and soil,which can improve the bearing capacity of RGP com- posite foundation.