基于拉拔法的索夹螺杆紧固力检测试验  

Experiment on detection of preload force in bolt clamp by pulling method

作　　者：蒋树勤[1,2] 周勇军 曹资源[1] 吴雨航 罗之然 杨帆 赵煜[1] JIANG Shu-qing;ZHOU Yong-jun;CAO Zi-yuan;WU Yu-hang;LUO Zhi-ran;YANG Fan;ZHAO Yu(Engineering Research Center of Highway Large Structure,Ministry of Education,Chang'an University,Xi'an 710064,Shaanxi,China;Guangxi Xingang Communications Investment Co.Ltd.,Qinzhou 535000,Guangxi,China)

机构地区：[1]长安大学公路大型结构安全教育部工程研究中心,陕西西安710064 [2]广西欣港交通投资有限公司,广西钦州535000

出　　处：《长安大学学报（自然科学版）》2024年第6期72-80,共9页Journal of Chang’an University(Natural Science Edition)

基　　金：广西科技重点研发计划项目(桂科AB23026125);中央高校基本科研业务费专项资金项目(300102214301,300102214403)。

摘　　要：为研究拉拔法检测螺杆紧固力误差产生原因,提高测量精度,以龙门大桥索夹为研究背景,基于理论分析与模型试验相结合的方法研究拉拔法误差影响机制。构建拉拔法螺杆两阶段有效紧固力的力学模型;设计室内M27螺杆模型,并利用压力传感器对螺杆两端螺母紧固力进行检测,分析张拉过程中紧固力的变化规律,并对理论模型进行验证;以龙门大桥索夹MJ45螺杆和MJ56螺杆为对象,开展拉拔超声法的紧固力检测方法研究,分析不同紧固力条件下,螺母松动前后的超声声时差、螺杆伸长量、螺杆有效紧固力与张拉力之间的关系。研究结果表明:螺杆的紧固力并非恒定不变,而是随着检测张拉力的增加而逐渐增长,当张拉端螺母松动时,张拉力通常比初始有效紧固力高10%~20%;拉拔超声法能够准确捕捉螺母松动的关键时刻;并由此提出了1.1~1.2的检测折减系数,以校准检测过程中可能出现的误差。研究结论可为实际工程的螺杆紧固力检测提供依据。In order to reveal the causes of errors in the detection of screw preload force by the pull-out method and to improve measurement accuracy,the cable clamps of the Longmen Bridge were taken as the example.This study combined theoretical analysis with model experiments to study the mechanism of the pull-out method.A mechanical model of the effective preload force of the screw during two-stage by pull-out method was constructed.The M27 screw model was made indoors,and pressure sensors were used to detect the preload force of the nuts at both ends of the screw,the change law of the preload force during the tensioning process was analyzed,which verified the theoretical model.The MJ45 and MJ56 screw of the cable clamp of the Longmen Bridge was used,and the pull-out ultrasonic method for preload force was studied,the relationship between the ultrasonic time difference,the effective preload force,elongation and tension force of the screw was analyzed under different preload force conditions.The results show that the preload force of the screw is not constant but increases gradually with the increase of the tension force.When the nut is loosening,the tension force is usually 10%to 20%higher than the initial effective preload force,and the pull-out ultrasonic method can accurately capture the critical moment of nut loosening.This study proposes a detection reduction factor of 1.1 to 1.2 to address the errors that may occur during the detection process.The research results can provide a basis for the detection of screw preload force in actual engineering.1 tab,13 figs,21 refs.

关 键 词：桥梁工程 索夹螺杆 模型试验 紧固力 超声纵波 拉拔法 

分 类 号：U44[建筑科学—桥梁与隧道工程]