摘要
海心桥是连接广州南北轴线的重要联系纽带,因上部复杂的异性结构体系,导致其下部基础承受了复杂的多向荷载作用。考虑土层-结构相互作用,建立海心桥超大直径群桩基础三维精细计算模型,分析基础结构与桩周土的力学性状,量化结构承载力安全富余度和土层稳定系数,而后综合评价多向荷载作用下群桩基础的可靠性。结果表明:(1)基础最大位移不足限值的10%,最小承载力安全系数为2.56,且最大应力显著小于强度设计值,结构未出现裂隙和强度破坏;(2)基础桩周土层受到挤压剪切效应,土层最小稳定性系数为2.58,没有出现塑性破坏;(3)综合土层与结构力学特性研判,实例群桩基础满足可靠性要求;(4)基础在单向荷载作用下表现出的受力变形一致性在多向荷载作用下不复存在;(5)承台-土层相互作用特性对桩基内力影响明显,桩基设计计算中应充分考虑。项目实施后,计算结果与实测值进行了对比验证,指出了规范中m法的局限性,并给出了修正建议,可为类似工程提供参考。
Haixin Bridge is an important link connecting the north and south axis of Guangzhou,has a complicated heterotypic structure system,which causes the lower pile foundation to bear multi-directional loads.The three-dimensional fine numerical analysis model for the super large diameter group pile foundation of Haixin bridge was established considering soil-structure interaction.The mechanical response of the foundation and the soil around piles were analyzed and the safety margin of structural bearing capacity as well as the soil stability coefficient were quantified.The reliability of pile group foundation under multi-directional loads were evaluated comprehensively.The results show that the maximum displacement of the foundation is less than 10%of the limit and the minimum bearing capacity safety factor is 2.56.The maximum stress is significantly less than the strength design value,while no cracks and strength failure appears in the structure.The soil around the foundation pile subjects to extrusion and shear,and the minimum stability factor of soil is 2.58,so no plastic failure occurs in the pile surrounding soil.Based on the analysis of soil and structural mechanical properties,the pile group foundation of an example meets the reliability requirements.When subjected to multidirectional loads,the force and deformation consistency of the foundation manifesting under unidirectional load no longer exists.The influence of cap-soil interaction characteristics on internal force of the pile foundation is significent,so it should be fully considered for calculation.After the implementation of the project,some numerical calculation results were compared with the actual measurements,and the effectiveness of the model was verified.The results of numerical calculation compared with that calculated by m-method,while some suggestions for amendments to the limitations of the m-method were given,which can provide references for similar projects.
作者
杨勇
杨春山
胡会勇
欧振锋
王巍
Yang Yong;Yang Chunshan;Hu Huiyong;Ou Zhenfeng;Wang Wei(Guangzhou Municipal Engineering Design&Research Institute Co.,Ltd.,Guangzhou 510060,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2023年第3期973-980,共8页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(51878192)
广东省自然科学基金(2020A1515011058)。
关键词
超大直径群桩
多向荷载
方案评价
数值模拟
m法修正
super large diameter pile group
multi-directional loads
schemes evaluation
numerical simulation
m-method modification
作者简介
杨勇(1972-),男,湖北黄冈人,硕士,正高级工程师,主要从事桥隧工程设计分析工作。E-mail:yangyong197211@163.com。
