Vibrating table test of human comfort under blasting vibration and its evaluation system construction

Blasting is widely used in national infrastructure construction as a paramount means of excavating hard rock and soil bodies. Blasting operations frequently occur in densely populated areas, endangering human physical and mental health. To reasonably evaluate the impact of blasting disturbance on personnel in adjacent areas and ensure the safety of the physical and mental health of personnel, constructing a human comfort evaluation system under the influence of blasting vibration is essential. Because of the uncertainty of human subjective feelings in the existing human comfort evaluation system under the influence of blasting vibration, the human vibration response test was performed by simulating blasting vibration using a vibrating table. Subjective sensations and electrocardiogram (ECG) changes were collected from 16 volunteers under the influence of blast vibration in different directions and at different levels. Subjective human sensations were quantified using the root mean square of successive differences (RMSSD) of adjacent RR interval values, a time-domain indicator of heart rate variability. The quantitative relationships among blasting vibration parameters, ECG index, and human subjective feelings were analyzed. A human comfort evaluation system under the influence of blasting vibration was constructed. The results show that the vertical direction is the main vibration direction affecting human comfort, and the influence of vibration on the human body is related to the main vibration-sensitive parts of the human body. When the main vibration-sensitive parts move up from the foot to the head, the influence is gradually increased. There is a link between the ST segment in the human ECG and human comfort. When the human body is subjected to vertical vibration, there is a drop in the ST segment in human ECG and human comfort is reduced, whereas there is no significant change under horizontal vibration. With an increase in vibration frequency and velocity, the human ECG index RMSSD shows a trend of first decreasing and then increasing under the vertical vibration; meanwhile, it decreased under the horizontal vibration, but the decreasing amplitude is limited. There is a quantitative relationship between the decline ratio of RMSSD and blasting vibration parameters and human subjective feelings. The quantitative relationships among blasting vibration parameters, ECG index, and human subjective feelings can realize the quantitative evaluation of human comfort under the influence of blasting vibration. In the blasting construction, a vibration velocity of 0.7 cm·s⁻¹ and a vibration frequency of 80 Hz in the vertical direction of the surface can be used as the control threshold of blasting engineering in the adjacent densely populated area.