Abstract:
The Sichuan-Tibet Railway under construction has a large number of tunnels under high geotemperature and high in-situ geostress.How to improve the accuracy of advanced geological prediction of these tunnels is a major difficulty in railway construction.Taking the Tunnel Seismic Prediction (TSP) method for advanced geological prediction as an example,analyses reveal that there are two major problems in the detection of the tunnels.On is that the use of emulsion explosives and plastic detonating tubes in blastholes under a high rock-temperature is liable to cause misfires,thus affecting data acquisition.The other is that the wave velocity differences between the excavated and unexcavated areas of tunnels under high in-situ geostress are not considered in data processing.Targeting these problems,this paper proposes six improvement measures,namely researching and developing detonation packs with a thermal insulation bag,establishing intelligent engineering assessment systems based on multiple geological information,changing the models of shock initiation of the TSP,popularizing new technologies and methods of advanced geological prediction,researching and developing advanced geological prediction systems suitable for Tunnel Boring Machines (TBMs),and improving the organizational management of geological prediction.All these measures can provide references for efficient detection of advanced geological prediction of tunnels in areas with high geotemperature and high in-situ geostress.