Numerical Study on the Propagation of Elastic Waves in GFRP Soil Nails

This study aimed to numerically investigate the propagation characteristics of elastic waves in GFRP soil nails. A two-dimensional axisymmetric finite element model was used to simulate the GFRP soil nail, and elastic waves were generated by an impulse load that represented hammer excitation. The results revealed that the elastic waves were reflected at both the defect location and nail end. The wave reflected from the defect exhibited a polarity opposite to that of the incident wave, whereas the end-reflected wave maintained the same polarity. This indicates that defect-reflected waves can be distinguished from end-reflected waves based on their polarities. In addition, the wave propagation velocity increased with the defect ratio, which was attributed to the differences in the effective stiffness and density governing wave propagation in the defective and grouted sections. These findings demonstrate that the elastic wave velocity and reflection characteristics can serve as effective indicators for assessing the integrity of GFRP soil nails.