Alternative seismische Quellen für die Vorauserkundung im konventionellen Tunnelbau

For seismic ahead-of-the-face prediction in tunnelling, sources with known properties are usually used, which, however, are not compatible with NATM. In order to integrate geophysical exploration into conventional tunnelling, the feasibility of construction machinery for generating seismic source signals was investigated. Passive monitoring during conventional tunnelling was used to analyse the seismic signals. Different radiation characteristics of drilling, blasting and bouldering could be identified and their characteristics regarding range and spectrum of the signal could be determined. In subsequent system tests, various machines used in NATM tunnelling were examined for their suitability as sources. The sensor positioning for source signal pickup was evaluated by stroke tests and during ongoing tunnelling operations. For the registration of the waves in the rock mass, different receivers with different geometries were used to characterize the wave field emitted to the front or side of the sources. In addition, the necessary processing steps were determined in order to make these signals usable for an ahead-of-the-face exploration. The results and data form a basis for further development into a practical technical solution for conventional tunnel construction.