Vibration analysis of the impact of the blasting construction of a power tunnel crossing underneath an existing subway station.

When tunnel blasting is commenced through the subway station, it will cause the vibration of the station structure. The purpose of this paper is to explore the maximum allowable vibration velocity of the normal operation of the subway during the implementation process of tunneling projects, and to ensure the normal and safe operation of the subway during the construction. An example is given regarding the down-traversing of the power tunnel to the Convention and Exhibition Center Station in the Yanta four circuit transmission line transformation project of Dalian, in which the stations are set along the track bed and bottom of the side walls of the rail line. The vibration response and corresponding main vibration frequency at each station were monitored. It was found that the response value of the vibration velocity of the track bed was distributed 0.5 to 2.0 cm/s; the average response value of the vibration velocity on one side wall for the previous construction on the rail line is 0.3 cm/s, and the distribution range of the main vibration frequency is 50 to 140 Hz; the response of the vibration velocity on the other side wall for the subsequent construction on the rail line is large with a mean value of 0.6 cm/s, and the distribution range of the main vibration frequency is 40 to 180 Hz. Based on these research results and the relevant specifications, the authors state that the monitoring work on the normal operation of the subway should be based on the monitoring work of the track bed and should allow the maximum vibration velocity of the particles to be 1.1 cm/s and 0.8 cm/s, and the corresponding main vibration frequency ranges of 70 to 100 Hz and 35 to 60 Hz, respectively. The present paper’s research results are of use as guidance for further studies and they put forth the maximum allowable particle velocity of subway operation during tunnel blasting construction of a down-traversing subway station. [ABSTRACT FROM AUTHOR]