超声波法测试受压混凝土应力的试验研究  

Experimental Study on Testing Stress in Compressed Concrete by Ultrasonic Method

作　　者：蔡秋香 王陶[1] CAI Qiu-xiang;WANG Tao(Research Institute of Highway,Ministry of Transport,Beijing 100088,China)

机构地区：[1]交通运输部公路科学研究院,北京100088

出　　处：《公路交通科技》2023年第5期50-57,共8页Journal of Highway and Transportation Research and Development

基　　金：中央级公益性科研院所基本科研业务费专项资金项目(2021-9082b,2021-9023a,2018-9017)。

摘　　要：为获得混凝土固体声学特性与应力状态之间的关系,从超声波在固体中的传播特性入手,对C30,C40,C50混凝土试块进行了单轴分级加载,在压缩荷载作用下对混凝土超声波传播速度进行了试验研究,并提出了超声波法检测混凝土应力的试验方法。针对混凝土结构在不同应力状态下的波速变化,获得了超声传播路径上的应力波速表达式。利用沿荷载方向正交平面传播的超声波对混凝土试件进行了声速测量,分析了混凝土应力与波速的关系。通过线性拟合混凝土在声弹性阶段的超声波波速与受压应力的关系,获得了混凝土在声弹性阶段线性系数a_(L)和b_(L)的值。根据试验数据建立了不同材料参数下的混凝土应力测试模型,模拟了不同压力下超声波在混凝土中传播情况,通过压应力与波速的模拟数据获得了模型的线性系数a_(m)和b_(m)的值。最后将不同应力下的波速模拟值和实测值作对比分析,验证了得出的线性系数能有效地表示超声波波速与应力的关系。结果表明:抗压强度前50%时,即声弹性阶段,超声波波速随应力的增大而线性下降;试件加载后期,即非声弹性阶段,波速呈非线性下降。通过本方法的测试,为分析超声波在混凝土中的传播特性提供了有益的尝试,可为混凝土应力检测技术研究提供参考。To obtain the relationship between the acoustic properties of concrete solid and stress state,starting from the propagation characteristics of ultrasonic waves in solid,the uniaxial graded loadings on C30,C40,and C50 concrete specimens are performed.The experimental study on ultrasonic propagation velocity in concrete under compression load is conducted,and an experimental method for ultrasonic testing of stress in concrete is proposed.In view of the variation of wave velocity in concrete structures in different stress states,expression of stress wave velocity along the ultrasonic propagation path is obtained.The sound velocity in concrete specimens is measured by using ultrasonic waves propagating in an orthogonal plane along the load direction,and the relationship between concrete stress and wave velocity is analyzed.By linear fitting the relationship between ultrasonic velocity and compressive stress in concrete during the acoustic elastic stage,the values of the linear coefficients(a_(L) and b_(L))of concrete in the acoustic elastic stage is obtained.The concrete stress testing models with different material parameters are established based on experimental data,the propagations of ultrasonic waves in concrete under different pressures are simulated,and the values of the linear coefficients(a_(m) and b_(m))of the model are obtained based on simulated data of compressive stress and wave velocity.Finally,the simulated and measured wave velocity values under different stresses are comparatively analyzed,which verified that the obtained linear coefficients can effectively represent the relationship between ultrasonic wave velocity and stress.The result indicates that(1)within the first 50%of compressive strength(the acoustic elasticity stage),the ultrasonic wave velocity linearly decreases with the increase of stress;(2)in the later stage of loading(the non acoustic elasticity stage),the wave velocity shows a nonlinear decrease.The testing by this method provides a beneficial attempt to analyze the propagation cha

关 键 词：桥梁工程 应力试验 超声波法 混凝土 无损检测 

分 类 号：U446[建筑科学—桥梁与隧道工程]