Geological mapping in tunnel escavations

Abstract

The geological and geotechnical studies for the design of tunnels are usually based on "punctual" information obtained from boreholes drilled from ground surface which prevents the studies to go further than the stage of pre-design before the excavation of the tunnel starts.

It is thus indispensable to gather the additional geological information during construction which will enable the completion of the design. ln this paper suggestions and recommendations are presented regarding the geological mapping of the tunnel excavated surfaces during construction.