In complex and sensitive environments, minimizing the disturbance of blasting vibration to surrounding residents is the primary concern during blasting construction. To explore a quantitative evaluation method for human dynamic response to blasting vibration, this study conducted single-subject in-situ blasting tests under strictly controlled safety conditions. By integrating digital image correlation (DIC) with a synchronous electrocardiogram (ECG) measurement system, the dynamic response characteristics of the human body surface under varying blasting vibration intensities were preliminarily analyzed. A height-dependent fitting relationship for peak particle velocity (PPV) was established under the present test conditions, with the body divided into two regions: below the waist and above the waist. Given the safety constraints of in-situ blasting tests, laboratory shake-table tests were also conducted. A comparative analysis using heart rate variability (HRV) evaluation indices was performed to preliminarily demonstrate the feasibility of using a shake table to simulate blasting vibration for human perception studies. The preliminary results indicate that under the present test conditions, the vertical vibration velocity of the human body is significantly higher than the horizontal velocity, with the vertical direction identified as the dominant vibration direction. The vertical vibration velocity exhibits a characteristic pattern of “attenuation below the waist and amplification above the waist”. Compared with the ground surface velocity, the attenuation rate in the lower body region ranges from 55.7% to 65.9%. The vibration velocity in the upper body region is amplified by a factor of 1.25 to 1.74. The horizontal vibration velocity decreases from the feet to the head, with an attenuation rate of 52.6% to 60%. The error in HRV indices obtained from the in-situ and shake-table tests is less than 10%, preliminarily confirming the feasibility of employing a shake table to simulate blasting vibration for human perception research. These exploratory in-situ tests provide a methodological reference for quantifying human vibration response and studying perceived ECG changes due to blasting vibrations.

The present investigation examines the effectiveness of a composite cushion charging structure, placed at the bottom of underwater boreholes, to mitigate bedrock damage induced by blasting excavation during cross-sea engineering. With reference to the embedded open caisson blasting project for a major cross-sea bridge, this research adopted a combined methodology of field sampling and controlled underwater explosion model tests. A piezoelectric ceramic detection system was employed to quantitatively analyze how the composite cushion, composed of iron-sand concrete layers with varying wave impedances, affects rock sample damage. Piezoelectric signals were processed via wavelet packet analysis to calculate the axial damage factor (DI) of the blast hole. Furthermore, by integrating fractal dimension theory with damage mechanics, a quantitative assessment was performed on the propagation behavior of cracks formed on the top surfaces of rock specimens under different test conditions. Results demonstrate that the implemented composite bottom cushion effectively mitigates blast-induced damage by significantly inhibiting macroscopic crack propagation, reducing surface crack density, and decreasing the axial penetration depth of cracks into the rock mass. Detailed analysis of axial damage reveals a clear trend, showing that the reduction in DI becomes more pronounced as the wave impedance of the cushion material increases. Specifically, within the borehole-affected zone (0–12 cm), the maximum achievable reduction in DI reaches 10.70%. At the bottom measurement point, reductions exceeding 90% are observed for the higher-impedance cushion configurations. In conclusion, this work confirms that employing a composite cushion charging structure in underwater drilling and blasting operations can significantly alleviate blast-induced damage to foundational bedrock. The findings also establish that axial damage to the rock mass can be effectively controlled by adjusting the wave impedance of the iron-sand concrete in the cushion layer. These outcomes offer valuable insights for optimizing blasting design and enhancing damage control in marine engineering projects.