沉桩方法对预制桩施工残余应力的影响  

Influence of Installation Method on Post-Installation Residual Stress in Preformed Piles

作　　者：刘俊伟[1] 俞峰[2] 张忠苗[1] 

机构地区：[1]浙江大学岩土工程研究所,杭州310058 [2]浙江理工大学建筑工程学院,杭州310018

出　　处：《天津大学学报》2012年第6期481-486,共6页Journal of Tianjin University(Science and Technology)

基　　金：国家自然科学基金资助项目(51078330);浙江省自然科学基金资助项目(Y1090610)

摘　　要：沉桩方法显著影响预制桩的施工残余应力,为此通过计算模拟对此进行研究.计算模型采用桩-土理想弹塑性荷载传递关系及残余摩阻力折线型分布假定,通过对预制桩沉贯和回弹过程进行能量分析,建立了施工全过程能量平衡方程.以沉桩循环为纽带建立桩侧摩阻力的退化模式,实现不同沉桩方法下残余应力分布的模拟.分析结果显示,沉桩循环越多桩身残余应力越小,桩端残余应力随总沉桩循环次数的增加呈指数型衰减.模拟分析结果与实测数据较为吻合.Post-installation residual stress locked in the preformed pile is significantly influenced by the installation method, which is studied through computational simulation in this paper. The proposed model adopts assumptions that the load transfer behavior along the pile-soil interface is ideally elasto-plastic and the distribution of residual fric- tion resembles a folded line. By conducting energy analysis of pile penetration and rebound, the energy equilibrium equation during pile installation is established. Then a simulation approach is put forward to calculate the residual stress distribution corresponding to different installation methods through the establishment of the friction fatigue mode on a primary consideration of the installation cycle history. Research results show that residual stress reduces with increasing installation cycles, and the residual point stress exhibits an exponential decay with the total installation cycles, which is consistent with the in-situ measurements.

关 键 词：预制桩 残余应力 沉桩方法 摩阻力 能量守恒 计算模拟 

分 类 号：TU473[建筑科学—结构工程]