Prediction of tunneling hazardous geological zones using the active seismic approach

ABSTRACT This paper presents a seismic method and a newly developed device to predict the hazardous geological zones ahead of a tunnel face. The equipment used to predict hazardous geological zones consists of three components: the seismic source, the acquisition unit, and the data processing unit. The following features enable this device to be a valuable tool in predicting hazardous geological zones: the precise trigger time detection; the application of semi‐liquid couplant, which improves geophone coupling with the surrounding rock; the filtering of the prominent tunnel acoustic wave interference; and a software package of information on hazardous geological zones. Through extensive detection exercises of hazardous geological zones in the excavations of nearly 100 tunnel projects in China, it has been demonstrated that this device can satisfactorily predict hazardous geological zones, such as faults, water‐bearing zones, karst caverns, etc., within 150 m in front of the tunnel faces.