水泥砂浆桩复合地基力学性状的数值分析  

Numerical Analysis for Mechanical Properties of Composite Foundation of Cement Mortar Pile

作　　者：栗金文 洪宝宁[1,2] 刘鑫[1,3] 孙键[1,2] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]河海大学岩土工程科学研究所,江苏南京210098 [3]河海大学隧道与城市轨道工程研究所,江苏南京210098

出　　处：《水利与建筑工程学报》2013年第6期26-30,共5页Journal of Water Resources and Architectural Engineering

基　　金：国家自然科学基金资助项目(51079052);广东省交通厅科技项目(200903005);江苏省普通高校研究生科研创新计划资助项目(CX10B 208Z;CXLX11 0437);河海大学中央高校基本科研业务费专项资金资助项目(2012B03014)

摘　　要：基于有限差分数值方法,考虑地基材料的非线性特性,通过模拟复合地基桩土应力比、复合模量随荷载、桩长、置换率和褥垫层的变化情况,分析了水泥砂浆桩复合地基桩土作用机理、桩土荷载分担规律及其变形特性。结果表明:桩体置换率增加,桩土应力比逐渐减小,复合模量逐渐增加,置换率超过20%,桩土应力比变化很小,并趋于稳定。置换率超过25%,置换率对复合模量的影响较小;桩长增加,桩土应力比增大,复合模量增加,桩长超过14 m,桩土应力比增长缓慢,复合模量亦趋于稳定;桩土应力比随着褥垫层厚度的增大而减小,随着褥垫层模量的增加而增大,宜设置褥垫层厚度100 mm^300 mm,褥垫层模量30 MPa^60 MPa。Taking the material＇ s nonlinear characteristics into consideration and based on the numerical method of finite difference, the soil-pile interaction mechanism, the soil-pile load sharing law and the deformation characteristics in the composite foundation of cement mortar pile are studied through analyzing the pile-soil stress ratio under different pile lengths, replacement ratios and cushion conditions. The results show that： With the increase of replacement ratio, the pile-soil stress ratio decreases and the composite modulus increases gradually; as the replacement ratio exceeds 20%, the pile-soil stress ratio has no significant change and tends to be stable. As the ratio exceeds 25%, the influence of replace- ment ratio on the composite modulus reduces sharply. The pile-soil stress ratio and composite modulus increase with the pile length increasing; as the pile length exceeds 14 m, the pile-soil stress ratio grows slowly, and the composite modulus tends to be stable. The pile-soil stress ratio decreases with the cushion thickness increasing, and increases with its modu- lus increasing; the cushion thickness should be set for 100 rnm - 300 mm and the cushion modulus＇ s appropriate range is 30 MPa- 60 MPa.

关 键 词：水泥砂浆桩 桩土应力比 复合模量 置换率 褥垫层 

分 类 号：TU472[建筑科学—结构工程]