基于分布式光纤传感技术的超长桩承载特性分析  

Bearing characteristics of ultra-long piles based on distributed fiber optic sensing technology

作　　者：付张鑫 曹文昭 吴旭君[1,2] 张兴杰 罗沐池 FU Zhangxin;CAO Wenzhao;WU Xujun;ZHANG Xingjie;LUO Muchi(Central Research Institute of Building and Construction Co.,Ltd.,MCC Group,Beijing 100082,China;China Jingye Engineering Co.,Ltd.,Beijing 100082,China)

机构地区：[1]中冶建筑研究总院有限公司,北京100082 [2]中国京冶工程技术有限公司,北京100082

出　　处：《岩土工程学报》2024年第S02期140-144,共5页Chinese Journal of Geotechnical Engineering

基　　金：五矿科技创新发展基金项目(JHCX20220011);国家重点研发计划项目(2023YFB3711605)。

摘　　要：为探究不同地质条件下超长桩承载变形特性及数值模拟中摩擦系数对桩-土相互作用的影响,以深圳湾超级总部某项目系列试桩为背景,采用FBG密集分布式光纤传感技术进行基桩内力测试,并采用ABAQUS有限元软件进行数值模拟,对比分析桩、土界面采用不同摩擦系数取值方式时土层平均侧阻力模拟结果。结果表明:(1)灌注桩承载变形特性与桩长和持力层性质密切相关,超长桩轴力沿深度方向基本呈线性递减,端阻比明显减小;持力层为强风化花岗岩层时,试桩轴力沿深度方向呈“大肚形”递减,端阻比低于17.1%。(2)数值模拟中摩擦系数取值方式会对土体侧阻力模拟结果产生较大影响,根据土层性质差异,对桩土界面采用多个摩擦系数能够提高模拟结果准确性。Based on a series of pile foundation tests from a project in the Super Headquarters Base in Shenzhen Bay,the load deformation characteristics of super-long piles under different geological conditions and the impact of friction coefficient on pile-soil interaction in numerical simulations are investigated.The FBG(fiber bragg grating)densely distributed fiber optic sensing technology is employed for internal force tests of the piles and the ABAQUS for numerical simulations.The results of the simulated average lateral resistance of the soil layers are compared and analyzed with different friction coefficient values applied to the pile-soil interface.The results indicate that:(1)The load deformation characteristics of bored piles are closely related to the pile length and the properties of the bearing stratum.The axial force of super-long piles decreases linearly with depth,and the end resistance ratio significantly reduces.In cases where the bearing layer consists of moderately weathered granite,the axial force of the test pile decreases in a"bulging"shape along the depth direction,with the end resistance ratio lower than 17.1%.(2)The method for determining the friction coefficient in numerical simulations significantly impacts the simulated lateral resistance of the soil.Multiple friction coefficients at the pile-soil interface can improve the accuracy of the simulated results,depending on the nature of the soil layer.

关 键 词：FBG密集分布式光纤传感技术 超长灌注桩 承载变形特性 数值模拟 侧阻力 

分 类 号：TU411[建筑科学—岩土工程]