STATE OF ART AND TRENDS OF ADVANCED GEOLOGICAL PREDICTION IN TUNNEL CONSTRUCTION

Advanced geological prediction has been an essential part in tunnel construction and has played an important role in aspects of informative construction,disaster prevention and safety guarantee in tunneling engineering. The state of the art and the trends of advanced geological prediction in drilling and blasting tunneling and TBM tunneling are summarized according to the available data. Great progress has been made in the advanced geological prediction in drilling and blasting tunneling with the emergence of a set of special methods,technologies and equipments,such as the reflection seismic method,the electromagnetic method and the electrical resistivity method,which gradually led to achieve quantitative detection and form a method of comprehensive advanced geological prediction. The comprehensive advanced geological prediction based on the fusion of multiple geophysical information and the method of combined inversion was considered an appropriate way for suppressing the multiple solutions and enhancing the reliability of advanced prediction. The methods of induced polarization and nuclear magnetic resonance have shown great prospects in the quantitative detection of water because of the sensitivity response of its parameters. Due to the particularity and complexity in the environment of TBM tunnel construction,some special detecting technologies did not meet the requirements of engineering practice which are at the preliminary stage of study and there have been no reliable and effective technologies for advanced prediction available generally. The latest developments in our group regarding three kinds of advanced prediction technology in drilling and blasting tunneling and its applicability to TBM tunnelling were described here. A system of comprehensive advanced geological prediction with four stages was proposed based on the theory of constrained joint inversion. The future studies are considered to be in the following four directions:(1) the further development of comprehensive quantitative detection during tunnel construction;(2) the technologies and equipments of advanced geological prediction in TBM tunnelling;(3) the theory and technology of precision probing at drilling;(4) the real time advanced prediction and construction disaster monitoring.