摘要
针对缺陷桩传统加固方法周期长、损耗高,以注浆加固法为主的微型加固工艺受施工因素影响较大,存在承载力不足的问题,提出钢管-注浆法微型加固方式,并进行室内模型桩轴压试验,考察了钢管比率、缺陷位置对缺陷加固桩极限承载力的影响。基于试验建立准确的有限元模型,总结了混凝土纵向应力分布规律与钢管Mises应力分布规律,对影响缺陷加固桩极限承载力的参数做了进一步分析。结果表明:缺陷加固桩的极限承载力随钢管比率增大而增大,且在钢管比率增大至2.4%时达到最佳;中部缺陷加固桩与下部缺陷加固桩极限承载力提升幅度最高分别可达完整桩的4.5%与15.8%;钢管端部混凝土截面的局部应力集中现象随缺陷位置下移而逐渐明显,钢管Mises应力水平的提升分别与钢管比率以及钢管长度有关;缺陷加固桩极限承载力与注浆体强度成正比,增大钢管壁厚与钢管直径对承载力贡献不大,钢管-注浆法在处理深部缺陷时表现突出,极限承载力提升幅度最高可达31.20%;建议加固深部缺陷桩时,沿桩身通长设置钢管并将钢管嵌固于桩端稳定持力层内一定深度。
In view of the long period and high loss of the traditional reinforcement method of defective piles,the micro-reinforcement technology based on grouting reinforcement method was greatly affected by construction factors,and there was a problem of insufficient bearing capacity.The micro-reinforcement method of steel tube-grouting method was proposed,and the axial compression test of indoor model piles was carried out.The influences of steel tube ratio and defect location on the ultimate bearing capacity of defective reinforced piles were investigated.Based on the test,an accurate finite element model was established,and the longitudinal stress distribution law of concrete and the Mises stress distribution law of steel tube were summarized.The parameters affecting the ultimate bearing capacity of the defect reinforced pile were further analyzed.The results show that the ultimate bearing capacity of the defect reinforced pile increases with the increase of the steel tube ratio,and reaches the best when the steel tube ratio increases to 2.4%.The ultimate bearing capacity of the mid-section reinforced defect reinforced pile and the lower-section reinforced defect reinforced pile can reach 4.5%and 15.8%of the complete pile respectively.The local stress concentration of the concrete section at the end of the steel tube gradually becomes obvious as the defect position moves down.The increase of the Mises stress level of the steel tube is related to the steel tube ratio and the length of the steel tube,respectively.The ultimate bearing capacity of the defect reinforced pile is proportional to the strength of the grouting body.Increasing the wall thickness of the steel pipe and the diameter of the steel pipe has little contribution to the bearing capacity.The steel pipe-grouting method is prominent in dealing with deep defects,and the ultimate bearing capacity can be increased by up to 31.20%.It is suggested that when reinforcing deep defective piles,steel pipes should be set along the whole length of the pile body and embedded in a certain depth of the stable bearing layer at the pile end.
作者
张信贵
张怀
张懿丹
罗冲
韩伟
严利娥
纪天骄
ZHANG Xingui;ZHANG Huai;ZHANG Yidan;LUO Chong;HAN Wei;YAN Li'e;JI Tianjiao(School of Civil Engineering and Architecture,Guangxi University,Nanning 530004,Guangxi,China;Guangxi University Design Institute Co.,Ltd.,Nanning 530007,Guangxi,China;Guangxi Geological Engineering Co.,Ltd.of China National Coal Group Corporation,Nanning 530007,Guangxi,China;China State Construction Engineering Corporation,Lanzhou 730099,Gansu,China)
出处
《建筑科学与工程学报》
北大核心
2025年第4期167-176,共10页
Journal of Architecture and Civil Engineering
基金
广西重点研发计划项目(桂科AB22035011)
广西科技重大专项(桂科AA23073005)
中化地质矿山总局项目(ZHTD202101)
广西高校中青年教师科研基础能力提升项目(2022KY1162)
广西壮族自治区住房和城乡建设厅项目(桂建科[2022]1号)。
关键词
缺陷桩加固
钢管-注浆法
轴压性能
试验研究
数值模拟
reinforcement of defective pile
steel tube-grouting method
axial compression performance
experimental study
numerical simulation
