新疆伊犁河大桥大型群桩基础试验与数值研究

依托新疆伊犁河大桥,基于其单桩静载自平衡试验结果,通过单桩有限元数值模拟与静载试验反演分析,确定土性参数,对大桥施工阶段群桩承载性状作了现场监测,并用ANSYS对承台群桩基础与土体共同作用进行三维弹塑性有限元分析,数值模拟所得群桩中各单桩桩顶和桩底反力与现场监测成果较一致。在用静载试验和现场监测成果验证数值分析的正确性下,用数值分析对群桩在各荷载工况下的单桩反力分布情况、承载变形曲线作了深入分析。结果表明,群桩基础受力处于合理的范围,几乎无不均匀沉降,基础下不同部位桩的受力随上部荷载的增加而有所调整,但最大与最小轴力差相对变化不大。所得结果可为类似的设计工作提供可靠的理论依据和参考。

Test and Numerical Analysis on Large-scale Group Piles Foundation of Yili River Bridge

Relying on Yili River Bridge in Xinjiang and based on self-balanced test result of single pile loading,the parameter of soil was determined through the simulation of finite element method concerning single pile and the back analysis on loading test.The bearing behavior of group piles during the construction period was inspected on the scene,and the interaction of cap-group piles-soil was analyzed with ANSYS software of 3-D elasto-plastic finite element method.The result demonstrates that the axial force of the top and bottom of each pile obtained through numerical analysis is in accordance with that of the inspected result on the scene.Under the guidance of the correspondence between loading test result and inspected result on the scene,the distribution of axial force of single-pile and bearing deformation curve under the different loadings on group piles were further numerical analyzed.The analytical result indicates that,the stress of group piles foundation is in a rational scope with uniform settlement;the load distribution of pile in different positions varies with the increasing of the upper load,but the relative variation between the maximal and the minimal axial force is not too large.The research provides a reliable theoretic basis and a reference to the similar projects.