砂土中斜桩-承台基础的水平承载特性研究  

Lateral bearing characteristics of inclined pile-cap system installed in sandy ground

作　　者：张磊 沈健豪 陈成 罗丹阳 ZHANG Lei;SHEN Jianhao;CHEN Cheng;LUO Danyang(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070

出　　处：《岩土工程学报》2024年第1期120-130,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52178353)。

摘　　要：通过开展室内模型试验,研究了砂土中斜桩-承台系统的水平承载特性,重点分析了桩身倾角及桩身抗弯刚度两个因素对桩顶水平位移、桩身弯矩分布的影响。利用有限元方法开展了与模型试验相对应的三维有限元分析,两者所得结果的对比表明所采用的有限元分析方法能较好地反映斜桩在水平荷载下的受力和变形特性。为了更好地与工程实际相对应,基于上述数值分析方法开展了原型尺寸的数值参数分析,考虑了桩体的弹塑性力学特性,探究土体弹性模量、桩身刚度以及桩身长度对斜桩-承台系统水平承载能力的影响。计算结果表明,相较于改变桩身的抗弯刚度,土体弹性模量的变化对斜桩-承台系统水平承载能力的影响更为显著;当桩长小于25 m(25倍桩径)时,桩长的增加能较明显降低桩顶水平位移响应,当桩长超过该值时,斜桩水平承载能力的提升效率下降。此外,基于试验数据开展了多元回归分析,获得了斜桩-承台系统桩顶水平位移的半经验预测公式,该公式的预测值与试验实测值及数值参数分析计算值的吻合度均较高,具有良好的适用性,有望能为砂土中斜桩工程的设计和分析提供一定的参考依据。The lateral bearing characteristics of inclined pile-cap systems installed in sandy soil are comprehensibly studied via a series of laboratory model tests,and the influences of inclination angle and flexural rigidity of pile on the lateral displacement at pile top and the distribution of pile bending moment are analyzed.Based on the model tests,a suite of three-dimensional finite element analyses are performed,and the favorable comparison of the test and numerical results convinces the capability of the adopted finite element analysis procedure in replicating the stress and deformation characteristics of the inclined piles in the model tests.Subsequently,a number of numerical parametric analyses based on the prototype models are implemented,accounting for the elastic-plastic mechanical properties of the pile,as well as the variations in elastic modulus of soil,flexural rigidity and length of the pile.The analysis results show that the variation in the elastic modulus of soil has a more significant effect on the lateral bearing capacity of the inclined pile-cap system than the change in pile flexural rigidity.When the pile length is less than 25 times the pile diameter(D),the increase of pile length can effectively reduce the lateral displacement response at the pile top.Otherwise,increasing the pile length has negligible effects on enhancing the lateral performance of the inclined pile-cap system.Furthermore,the multivariate regression analysis is performed based on the test data of lateral displacement at pile top,from which a semi-empirical equation can be derived.The performance of this semi-empirical equation is favorably examined by both the relevant experimental data and the numerical parametric analysis results,which likely provides a useful reference for the design and analysis of the inclined pile-cap system in sandy ground.

关 键 词：斜桩-承台系统 水平承载能力 有限元分析 模型试验 

分 类 号：TU437[建筑科学—岩土工程]