采用承插式桩接头的预制方桩受弯承载性能研究
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摘要
由济南R1线工程的预制方桩受弯承载力试验结果可知,采用承插式桩接头的预制方桩的受弯承载力取决于接头的承载性能,由此提出了该预制方桩受弯承载力极限状态的检验标志为桩身挠度、裂缝宽度达到规范限值或桩接头屈服,以此给出预制方桩的受弯承载力计算式,同时对预制方桩的受力变形过程进行阶段划分。结合数值分析方法,分析了预制方桩各受力阶段的桩接头受力变形特征,建立了桩接头的受力变形模型,验证了以Tresca屈服准则判别桩接头屈服的正确性,并推导了桩接头受弯承载力计算式,并以试验结果验证了该式的正确性。结果表明:当桩接头材料达到屈服强度时,挠度、裂缝宽度均远小于规范限值。桩接头上部受压区初始以销栓传递应力给腹板、上翼板,腹板、上翼板与端板接触后,由腹板、上翼板直接承受压应力;下部受拉区以销栓传递应力给腹板、下翼板,由受压侧腹板、下翼板承受受拉区应力,且受拉区受压侧腹板、下翼板首先屈服,并以此作为计算桩接头受弯承载力的依据。受拉区腹板、下翼板第二主应力比第一、第三主应力小两个数量级。根据桩接头受压区分布情况,桩接头屈服时,受压区应力分布为"倒三角形",并以此确定受压区合力位置。
Based on bearing capacity tests of prefabricated square pile in Jinan rail transit R1 construction,bending capacity of prefabricated square pile with socket and spigot joint was obtained,which was determined by the pile joint.The ultimate bending limit states of prefabricated square pile including the deflection and crack width limits and pile joint yielding were proposed. Formula for computing the bending capacity was deduced and process of deformation was divided. With numerical analysis method,bending performance of prefabricated square piles was studied and model of bending performance was built,the correctness of Tresca yield criterion for judgment of pile joint yield was proved and the explicit expression of bending performance for pile joint was derived,and the correctness of the explicit expression was verified through experimental study. The results show that deflection and crack width are far less than limits when pile joint reaches yield strength. The stress in the upper compression part of the pile joint is transmitted to the web and upper flange by the pin bolt initially,then the web and upper flange directly bear compressive stress when web and upper flange are in contact with end plate. The stress in the lower tension part is transmitted to the web and lower flange by the pin bolt. The compression side web and lower flange bear tensile stress and tend to yield firstly,which is the basis for calculating the bending bearing capacity of the pile joint. The second principal stress is smaller two orders in magnitude than the first and the third principal stress. According to distribution of compression zone of pile joint,stress distribution on compression zone is inverse triangle when pile joint reaches yield strength and can be used to determine the point of resultant force.
Based on bearing capacity tests of prefabricated square pile in Jinan rail transit R1 construction,bending capacity of prefabricated square pile with socket and spigot joint was obtained,which was determined by the pile joint.The ultimate bending limit states of prefabricated square pile including the deflection and crack width limits and pile joint yielding were proposed. Formula for computing the bending capacity was deduced and process of deformation was divided. With numerical analysis method,bending performance of prefabricated square piles was studied and model of bending performance was built,the correctness of Tresca yield criterion for judgment of pile joint yield was proved and the explicit expression of bending performance for pile joint was derived,and the correctness of the explicit expression was verified through experimental study. The results show that deflection and crack width are far less than limits when pile joint reaches yield strength. The stress in the upper compression part of the pile joint is transmitted to the web and upper flange by the pin bolt initially,then the web and upper flange directly bear compressive stress when web and upper flange are in contact with end plate. The stress in the lower tension part is transmitted to the web and lower flange by the pin bolt. The compression side web and lower flange bear tensile stress and tend to yield firstly,which is the basis for calculating the bending bearing capacity of the pile joint. The second principal stress is smaller two orders in magnitude than the first and the third principal stress. According to distribution of compression zone of pile joint,stress distribution on compression zone is inverse triangle when pile joint reaches yield strength and can be used to determine the point of resultant force.
引文
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[2]ZHANG LImin,LI DIANqing,TANG W H.Impact of routine quality assurance on reliability of bored piles[J].Journal of Geotechnical and Geoenvironmental Engineering,2006,132(5):622-630.
[3]POULOS H G.Pile behaviour-consequences of geological and construction imperfections[J].Journal of Geotechnical and Geoenvironmental Engineering,2005,131(5):538-563.
[4]徐中华.上海地区支护结构与主体地下结构相结合的深基坑变形性状研究[D].上海:上海交通大学,2007:1-15.(XU Zhonghua.Deformation behavior of deep excavations supported by permanent structure in Shanghai soft deposit[D].Shanghai:Shanghai Jiaotong University,2007:1-15.(in Chinese))
[5]MASUDA T.Behavior of deep excavation with diaphragm wall[D].Cambridge,Massachusetts:Massachusetts Institute of Technology,1993:5.
[6]陈俊生,莫海鸿.盾构隧道管片接头抗弯刚度的三维数值计算[J].铁道学报,2009,31(4):87-91.(CHEN Junshen,MO Haihong.Three-dimensional FEM analysis on flexural rigidity of segment joints in shie Id tunnel[J].Jounal of the China Railway Society,2009,31(4):87-91.(in Chinese))
[7]曾东洋,何川.地铁盾构隧道管片接头抗弯刚度的数值计算[J].西南交通大学报,2004,39(6):744-748.(ZENG Dongyang,HE Chuan.Numerical simulation of segmant joint bonding stiffness of metro shield tunnel[J].Jonmal of Southwest Jiaotong University,2004,39(6):744-748.(in Chinese))
[8]宋克志,袁大军,王梦恕.盾构法隧道施工阶段管片的力学分析[J].岩土力学,2008,29(3):619-623.(SONG Kezhi,YUAN Dajun,WANG Mengshu.Segmental mechanical analysis of shield tunnel during construction stage[J].Rock and Soil Mechanics,2008,29(3):619-623.(in Chinese))
[9]何川,张建刚,杨征.武汉长江隧道管片衬砌结构力学特征模型试验研究[J].土木工程学报,2008,41(12):85-90.(HE Chuan,ZHANG Jiangang,YANG Zheng.Model test study oil the mechanical characteristics of segment lining for the Wuhan Yangtze River tunnel[J].China Civil Engineering Journal,2008,41(12):85-90.(in Chinese))
[10]李兆平,王臣,苏会锋,等.预制装配式地铁车站结构榫槽式接头力学性能研究[J].中国铁道科学,2015,36(5):7-11.(LI Zhaoping,WANG Chen,SU Huifeng,et al.Mechanical property of tenon-groove joints for metro station constructed by prefabricated structure[J].China Railway Science,2015,36(5):7-11.(in Chinese))
[11]刘建洪.明挖装配式地铁车站结构设计优化及施工过程力学特性研究[D].成都:西南交通大学,2007:1-20.(LIU Jianhong.Study on the design optimization of the fabricated structure of the subway station constructed by open cut method and the mechanical behaviour of construction[D].Chengdu:Southwest Jiaotong University,2007:1-20.(in Chinese))
[12]一般工程用铸造碳钢件:GB/T 11352—2009[S].北京:中国标准出版社,2009.(Carbon steel casting for general engineering purpose:GB/T 11352—2009[S].Beijing:Standards Press of China,2009.(in Chinese))
[13]锻件用结构钢牌号和力学性能:GB/T 17017—1997[S].北京:中国标准出版社,1997.(Structural steel grades and mechanical property for forgings:GB/T17017—1997[S].Beijing:Standrads Press of China,1997.(in Chinese))
[14]六角头螺栓:GB 5782—2000[S].北京:中国质检出版社,2000.(Hexagon head bolts:GB 5782—2000[S].Beijing:China Zhijian Publishing House,2000.(in Chinese))
[15]混凝土结构设计规范:GB 50010—2010[S].北京:中国建筑工业出版社,2010.(Code for design concrete structures:GB 50010—2010[S].Beijing:China Architecture&Building Press,2010.(in Chinese))
[16]白睿,郝际平,田黎敏,等.螺栓撬力修正计算方法[J].建筑结构,2013,43(9):88-91.(BAI Rui,HAO Jiping,TIAN Limin,et al.Modified calculation method for prying action[J].Building Structure,2013,43(9):88-91.(in Chinese))
[17]钢结构高强度螺栓连接技术规程:JGJ 82—2011[S].北京:中国建筑工业出版社,2011.(Techical specification for high strength bolt connections of steel structures:JGJ 82—2011[S].Beijing:China Architecture&Building Press,2011.(in Chinese))
[18]徐建设,陈以一,韩琳,邓长根.普通螺栓和承压型螺栓抗剪连接滑移过程[J].同济大学学报(自然科学版),2003,31(5):510-514.(XU Jiangshe,CHEN Yiyi,HAN Lin,DENG Changgen.Slip process analysis of regular bolt and bearing type high-tensile bolt shear connections[J].Journal of Tongji University(Natural Science),2003,31(5):510-514.(in Chinese))
[19]钢结构设计规范:GB/T 50017—2003[S].北京:中国计划出版社,2003.(Code for design of steel structures:GB/T 50017—2003[S].Beijing:China Planning Press,2003.(in Chinese))
[20]吴永端.应变花应力分析的图解法[J].南京航空学院学报,1980,12(1):128-150.(WU Yongduan.A graphical method of stress analysis strain rosette[J].Journal of Nanjing University of Aeronautics and Astronautics,1980,12(1):128-150.(in Chinese))
[21]徐芝纶.弹性力学[M].北京:高等教育出版社,2006:9-38.(XU Zhilun.Theory of elasticity[M].Beijing:Higher Eduction Press,2006:9-38.(in Chinese))
[22]混凝土结构工程施工质量验收规范:GB 50204—2015[S].北京:中国计划出版社,2015.(Code for quality acceptance of concrete structure construction:GB 50204—2015[S].Beijing:China Planning Press,2015.(in Chinese))