混凝土表面开口裂缝对近表面声波影响

The influence of surface opening cracks on the sound wave near concrete surface

基于混凝土近表面不同波型的声速,分析开口裂缝对声波的影响。有限元仿真结果表明,激励源辐射的初始纵波P经裂缝端点衍射产生纵波P-P与横波P-T,P-T以一定的角度射向混凝土表面经模式转换产生纵波P-T-P;初始横波T在裂缝端点衍射产生纵波T-P与横波T-P;初始瑞利波R在裂缝端点衍射后除了产生纵波R-P与横波R-S外继续沿着固体表面传播(R-R)。在此基础上,基于变型波到达接收阵元的时刻定量检测裂缝的深度,检测结果较单面平测法具有更高的信噪比与检测精度,可辅助单面平测法更精确地定量检测混凝土开口裂缝的深度。

Based on the velocities of different wave modes near concrete surface, the influences of surface-crack on these wave modes are analyzed. Finite Element Method （FEM） simulation results show that the original longitudinal wave P is diffracted at crack tip to generate longitudinal wave P-P and transverse wave P-T, and the latter propagates onto surface with a certain angle of incidence to result in a new longitudinal wave P-T-P; the original transverse wave Tis diffracted at crack tip to generate longitudinal wave T-P and transverse wave T- T, the original Rayleigh wave R is diffracted at crack tip to generate longitudinal wave R-P and transverse wave R-T, and continues to propagate along the solid surface （R-R）. On the basis of the simulation results, the multi-mode wave method by measuring the arrival times of variant waves to receiver can be utilized to measure the depth of surface crack with higher signal-to-noise ratio and more precise resolution compared to the single plane method.