The Study On Advanced Geological Prediction Of Daxiangling Tunnel Of Yaan-Lugu Motorway

In the large-scale highway construction of the western region in China, the complicated geological conditions, mountains peaks and vertical and horizontal ravines have brought great difficulty to the highway construction, thus the tunnel project is particularly important, while in the process of tunnel construction, proving the geology conditions in front of the tunnel's working face is one of the important controlling factors of the tunnel construction safety. In order to ensure the safety of the tunnel construction, advanced tunnel geological prediction is an important part of tunnel construction processes.This paper elaborated the engineering geological conditions of Daxiangling tunnel area, on the basis of collecting previous studies and analyzing the techniques and methods at home and abroad, modern geophysical methods were used to predict tunnel geological disasters, and experiences were summarized during the real work of forecasting Daxiangling tunnel geological disasters. This paper mainly focused on the following aspects:1. Various methods for advanced geological prediction were systematically summarized, and the working principle, working methods, interpretation methods and the application effects of geological radar were elaborated. Comparing the probe findings and survey data with engineering practice showed that ground geological radar for the detection of Daxiangling tunnel had a good prediction results, but there are many factors affecting the forecast accuracy in the process.2. Through the practical application of TSP technology in Daxiangling tunnel, its working principle and working methods were described. Three kinds of systems named TSP203, TGP206 and TGP12 were adapted to probe in the long-distance observation of Daxiangling tunnel, and comparing the observation results with engineering practice, the advantages and disadvantages of three types of detection systems were summarized.3. With geological analysis as the core, a variety of advanced geological forecast methods were used to predict tunnel lithology, rock types, faults, fracture zones, as well as geological conditions of projects like groundwater and geological disasters like water inflow.4. Through the forecast analysis of Daxiangling tunnel, a set of general concept of tunnel geological disasters prediction was established:Taking geological analysis as the key, TSP technology was used for advanced forecast of long-distance detection, according to the conclusions of the detection analysis, and ground penetrating radar was used for medium-range detection, finally, tunnel face sketch was used for short-range forecasting, and advance borehole drilling was adapt to predict and verify in some special sections. Advanced geological forecast would eventually be a procedure of the normal construction process.