基于能量守恒的预制桩施工残余应力模拟

预制桩施工阶段形成的残余应力较难由实测获得，其重要影响鲜受关注。从能量守恒原理出发，可模拟沉桩引起的桩身残余应力分布。计算模型采用剪切带理想弹塑性荷载传递关系及残余摩阻力折线型分布假定，以桩身弹性变形能为纽带，对预制桩沉贯和回弹过程进行能量分析，建立了施工全过程的能量平衡方程。参数分析显示，桩长径比与剪切带摩擦性状是影响桩身残余应力的关键因素。该模型能较合理预测某原型试桩的施工残余应力。

Simulation of post-installation residual stress in preformed piles based on energy conservation

Installation of a preformed pile gives rise to residual stress locked in the pile.Such stress is difficult to be measured in-situ,hence little focus has been paid on its significant effect.Alternatively,a simulation approach is put forward in this study by incorporating the principle of energy conservation.The proposed model adopts assumptions that the load transfer behavior along the pile-soil interface is ideally elastoplastic and the distribution of residual friction resembles a folded line.By looking through the physical process of pile penetration and rebound,the energy equilibrium equation during pile installation is established on a primary consideration of the elastic deformation energy of pile.Parametric studies show that the ratio of pile length to pile diameter and the interface shear friction are two key issues affecting pile residual stress.The rationality of this model is assessed against the measured post-installation residual stress of a full-scale pile.