Safety Evaluation of the Influence of Mountain Blasting on Piles Under Construction

Blasting excavation can pose significant risks to adjacent structures, particularly during concrete pouring. Therefore, evaluating their safety is crucial. In addition, the influence of blasting vibration on the vibration of the foundation and the superstructure is different. Currently, there are only allowable vibration values in the time domain range affected by blasting construction on the foundation structure at vibration frequencies of 1–10 Hz and 50 Hz. There is a lack of allowable vibration values in the range of 10–50 Hz. Based on a liquefied natural gas (LNG) project in Zhejiang, China, this paper studies the safety evaluation index for the vibration of piles under the storage tank through in situ blasting tests and numerical simulations. The vibration velocity attenuation curve of the site, which can accurately predict the pile vibration velocity induced by blasting, is obtained by fitting the experimental results using Sodev’s formula. It is found that the vibration velocity gradually increases from the pile toe to the pile top. As the distance to the blasting source increases, the maximum vibration velocity of the pile top gradually decreases. The peak vibration velocity at the pile top is different from that at the ground surface around the pile. Their ratio, which can reach up to 1.33, gradually increases with the decreasing distance to the blasting source and the increasing concrete strength. The predominant frequency is greater than 10 Hz. For the pile whose concrete strength is lower than 50% of the design strength, blasting has little impact when the vibration velocity is less than 10.16 mm/s. The experimental results supplement the relevant experimental data within the range of 10–50 Hz. This study can provide references for similar projects.