Tunnel Seismic Prediction

The Tunnel Seismic Prediction detects changes in rock mass such as irregular bodies, discontinuities, faults, and fracture zones ahead of the tunnel face. It can be employed as a predictive method during the excavation process for both drill & blast and TBM headings. No access to the face is required to perform measurements. Acoustic signals are produced by a series of shots of small charge. Two sensor probes, consisting of highly sensitive triaxial receivers, are installed in special casings firmly cemented into boreholes of both side walls. The 3-component receivers pick up the seismic signals reflected back from any kind of discontinuity in the rock mass ahead. Highly sophisticated processing & evaluation software is utilized for data processing & interpretation. The capability of the system to record the full wave field of compressional and shear waves enables the determination of rock mechanical properties such as Poisson ratio, shear modulus, and Young’s Modulus within the prediction area. The final 2D or 3D results produced by the system software present detected events and boundary planes crossing the tunnel axis coordinates ahead of the face.