三向斜锚短桩基础拉拔荷载作用下桩锚节点的受力特性分析  

Mechanical characteristics of pile-anchor joints of three-way inclined anchor-short pile foundation under tension

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作  者:田雷 谢强[2,3,4] 段军 陶富涛 班宇鑫 傅翔 晏彬淇 TIAN Lei;XIE Qiang;DUAN Jun;TAO Fu-tao;BAN Yu-xin;FU Xiang;YAN Bin-qi(State Grid Economic and Technological Research Institute Co.,Ltd.,Beijing 102209,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China;National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Aears(Chongqing),Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education,Chongqing University,Chongqing 400045,China;School of Civil and Hydraulic Engineering,Chongqing University of Science and Technology,Chongqing 401331,China;School of River and Ocean,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区:[1]国网经济技术研究院有限公司,北京102209 [2]重庆大学土木工程学院,重庆400045 [3]库区环境地质灾害防治国家地方联合工程研究中心(重庆),重庆400045 [4]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045 [5]重庆科技大学土木与水利工程学院,重庆401331 [6]重庆交通大学河海学院,重庆400074

出  处:《岩土力学》2025年第1期278-288,共11页Rock and Soil Mechanics

基  金:国家电网公司科技项目(No.5200-202256088A-1-1-ZN,No.16200317003K)。

摘  要:针对输电线路中山区上覆土层、下卧岩层的地层条件,为增加桩基础抗拉拔性能,提出了一种锚固板钢筋锚固形式的斜锚短桩基础,开展了钢筋混凝土短桩-3向斜锚杆基础节点室内模型试验,研究了拉拔荷载作用下桩锚节点的受力特性与破坏机制。结果表明:短桩与锚筋协同工作,最先于锚杆节点处产生拉裂缝,进而形成竖向主裂缝不断向桩顶延伸,致使试件整体劈裂破坏。试件的开裂荷载约为150 kN、屈服荷载约为1611 kN、极限荷载约为1845 kN,破坏前锚筋全部屈服,桩内纵筋、箍筋均未屈服,斜锚表现出稳定的锚固性能。斜锚短桩基础受力较小时,桩锚间的锚固作用主要由钢筋直锚段的黏结作用承担;随着荷载逐渐增加,锚固作用则主要由锚固板端头的承压作用承担,锚杆肋间斜向应力与短桩相应位置斜截面切应力τ_α叠加,使得锚筋周围混凝土裂缝发生偏转,加剧混凝土裂缝向桩表面发展。研究成果可为复合型基础的设计提供借鉴,并为其变形特性与破坏机制研究提供参考。To enhance the tensile performance of pile foundations,an inclined anchor-short pile foundation with an anchor plate was proposed for transmission lines in areas with overlying soil and underlying rock layers in mountainous regions.An indoor model test of a reinforced concrete short pile with three inclined anchor foundation joints was conducted to study the mechanical characteristics and failure mechanisms of these joints under multi-directional tension.The results show that the short pile and anchor bar work synergistically.The tensile crack first occurs at the joint of the anchor rod,then the vertical main crack extends to the pile top,leading to the overall splitting and failure of the specimen.The cracking load of the specimens is approximately 150 kN,the yield load is approximately 1611 kN,and the ultimate load is approximately 1845 kN.Before failure,all the anchor bolts yield,while the longitudinal bar and stirrup inside the pile do not yield,indicating stable anchoring performance of the inclined anchor.When the load on the inclined anchor-short pile foundation is small,the anchoring action between the pile and anchor is mainly borne by the bonding action of the straight anchor section of the steel bar.As the load increases,the anchoring effect is mainly borne by the bearing effect of the anchoring plate.The oblique stress between the anchor ribs combines with the corresponding oblique shear stressatin the short pile,causing the concrete cracks around the anchor bars to deflect and exacerbating the development of concrete cracks to the pile surface.This study provides a reference for the design of composite foundations and the study of deformation characteristics and failure mechanisms.

关 键 词:斜锚短桩基础 锚固板 节点 受力特性 破坏机制 

分 类 号:TU473[建筑科学—结构工程]

 

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