Seismic prediction ahead of a tunnel face - Modeling, field surveys, geotechnical interpretation -

Abstract

An important precondition for underground construction is a detailed knowledge of the soil and/or rock conditions in the area of the construction. In order to overcome existing limitations in classical exploration methods, research and development for exploration ahead of a tunnel face focuses on: hardware development for excavation integrated measurements, modelling and processing of data measured under these specific circumstances, and integrative interpretation of seismic results with other data from the excavation, from geological mapping, and from exploratory drilling, where available. Finite difference modelling of seismic wavefields around tunnels has shown the general feasibility of seismic measurements for imaging structures ahead of a tunnel face. The modelling results were confirmed by field measurements in various tunnel sites. The integrated interpretation of seismic data with all available geological and geotechnical information is currently in the state of development and aims, in the middle to long term perspective, at an “a priori” detection of structures ahead of the face.