竖向受荷横截面异形桩弹塑性变分解  

Elasto-plastic variational solution for vertically loaded noncylindrical piles

作　　者：李籼橙 周航[1,2] 亓戈平 LI Xiancheng;ZHOU Hang;QI Geping(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Chongqing University,Chongqing 400045,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045

出　　处：《岩土工程学报》2023年第1期122-133,I0008,共13页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金面上项目(51978105)。

摘　　要：现有计算理论无法严格考虑弹塑性土中竖向受荷横截面异形桩的异形效应。针对该问题,基于虚功原理推导出桩-弹塑性土模型的控制方程,采用保角变换技术克服了复杂边界条件控制方程求解问题,结合双曲形D-P本构模型的本构积分算法获得弹塑性土中竖向受荷横截面异形桩的半解析算法,建立了能够考虑横截面异形效应的竖向受荷横截面异形桩荷载传递理论模型。将理论模型的预测结果与有限元计算结果对比,验证了理论模型的可靠性和计算的高效性。最后,通过参数分析探讨了横截面异形效应对荷载沉降曲线的影响,结果表明:在正常工作荷载下,横截面异形效应对桩顶沉降影响不大;横截面异形效应主要对桩的极限承载力大小产生影响。The existing analytical or semi-analytical methods cannot rigorously capture the geometrical effects of noncylindrical piles in elasto-plastic soils.To solve this issue,based on the principle of virtual work,the governing equations for the pile-soil system are derived.Solving the governing equation with a complex boundary is overcome by the conformal mapping technique.A semi-analytical algorithm for the vertically loaded noncylindrical piles in elasto-plastic soils is developed by combing the use of integral algorithm for the hyperbolic D-P constitutive model.A general theoretical model for the load transfer of the vertically loaded noncylindrical piles considering the geometrical effects is proposed.The reliability and efficiency of the proposed semi-analytical method is validated by comparing the predicted results with those of FEM.Finally,detailed parametric studies are conducted to investigate the geometrical effects on the influences of load-settlement curve.It is found that the non-circular cross-section has insignificant influences on the settlement of the pile head under working loads,which principally affects the magnitude of the ultimate bearing capacity of the pile.

关 键 词：弹塑性土 横截面异形桩 虚功原理 保角变换 D-P本构模型 荷载传递 

分 类 号：TU473[建筑科学—结构工程]