超声波桩基检测多物理场数值模拟

Numerical Simulation of Multi-physics Field for Ultrasonic Testing on Pile Foundations

随着我国建筑行业的快速发展,桩基运用也越来越广泛,桩基的完整性检测至关重要。超声波无损检测技术具有检测深度大、范围广、灵敏度高、速度快等优点,已成为桩基检测中运用最多的检测方法。超声波检测对缺陷的判定方法缺少理论支撑,出现漏判、误判的情况。为了准确有效的检测桩基的完整性,通过Comsol Multiphysics有限元分析软件建立二维桩基无损检测模型,利用压力声学、固体力学模块和压电效应进行多物理场耦合。通过声速和波形,验证超声波模型的准确性。建立不同尺寸的空洞缺陷模型,通过对声压和声时的分析,提出空洞尺寸对超声传播影响规律。通过空洞在中心轴上位置的变化,分析对比声压与换能器相对距离关系,空洞缺陷靠近发射换能器相对于接收换能器影响更大。

With the rapid development of China’s construction industry,the pile foundation is being increasingly applied,and the integrity inspection of a pile foundation is very important.Ultrasonic nondestructive testing technology,owing to its advantages of large detection depth,wide range,high sensitivity and fast speed,has been most widely used in pile foundation testing.However,ultrasonic testing lacks theoretical support for the determination of defects,resulting in missed and erroneous judgments.In order to accurately and effectively test the integrity of the pile foundation,a twodimensional non-destructive testing model for the pile foundation was established through Comsol Multiphysics finite element analysis software,which conducts multi-physics coupling with pressure acoustics,solid mechanics modules and piezoelectric effects.The accuracy of the ultrasonic model is verified through sound velocity and waveform.The models of cavity defects of different sizes were established,and the influence law of cavity size on ultrasonic propagation was proposed through the analysis on sound pressure and sound time.Based on the change of the cavity’s position on the central axis,the relative distance relationship between sound pressure and the transducer is analyzed,and it’s found that the cavity defect closer to the transmitting transducer has a greater influence than closer to the receiving transducer.