Development and Application of Cableless Seismic Survey System in Mountain Tunnel
A cableless seismic exploration system that can be used in the construction of mountain tunnels for quantitative rock condition evaluation near the tunnel face and investigation in front of the tunnel face was developed. The system requires no cable for the exploration and its simple system configuration achieves high-precision exploration in a tunnel construction cycle, for example using rock-bolts of tunnel support as receivers. Quantitative rock condition evaluation near the tunnel face can be conducted with refraction-method seismic exploration at the tunnel walls by using hammering as the wave source. In addition, about 12 successive measurements of elastic waves produced by excavation blasting predicted the rock condition ahead of the tunnel face (max. about 150m) with reflection-method seismic exploration. In this paper, we present the configuration of our system and an example of its successful application in the construction of an actual tunnel site.