On-site tests investigating the effects of blasting vibration amplitude on the dynamic response of thin spray-on liner

Studying the dynamic response of support systems under blasting impact holds significance for ensuring the safety of underground space and roadways. Thin spray-on Liner (TSL), an innovative roadway and tunnel support material, has gained considerable global attention. However, the effects of the blasting vibration amplitude on its dynamic response remain unclear. This study, employing 14 on-site blasting tests with varying charges, generated distinct amplitudes of blasting vibrations on the TSL. Subsequently, by refining the on-site blasting dynamic data testing environment, measurements were obtained for the dynamic displacements, dynamic strains occurring on the TSL spray-on layer surface, and dynamic pressures generated within the layer. The test results demonstrate that the blasting vibration amplitude influences the peak values and peak loading rates of the dynamic signals. Specifically, the dynamic displacement and tensile strain peaks exhibit a linear positive correlation with the blasting vibration amplitude. Meanwhile, the dynamic pressure peaks show a nonlinear positive correlation with the vibration amplitude. The peak loading rates of the dynamic displacement and dynamic pressure increase with the augmentation of the vibration amplitude. The relationships between dynamic displacement peaks, dynamic tensile strain peaks, dynamic pressure peaks, and explosive charge quantity, as well as the distance from the explosive source, can be adequately described using power functions. The permissible blasting vibration velocity for TSL support can be ascertained through the relationship between dynamic displacement, dynamic strain, and vibration amplitude, offering a reference for blasting vibration protection in roadway support involving TSL.