Advanced Geological Prediction Technology Based on Tunnel Face Borehole Drilling

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In the process of drilling, the drilling tool contacts with the rock and soil directly. The response information of the drilling tool reflects the mechanical properties of the rock and soil comprehensively. A large amount of geological data hidden in the response information of the drilling tool can be used to analyze and determine the mechanical parameters and spatial distribution of the rock and soil, thus providing an important reference index for the identification of the formation interface and the classification of the surrounding rock. At present, the response information of drilling tools in the field of geotechnical engineering has not been collected, resulting in a great waste of data resources. To make full use of the relevant parameter information in tunnel blasthole drilling, the relationship between the parameters and the quality of surrounding rock is collected and established, and in combination with the geological situation of the face, the level of surrounding rock in front of the face is predicted. The tunnel of Sandu high-speed rail in Guizhou Province is used to conduct research on advance geological prediction technology based on borehole drilling of tunnel face, and the following results are obtained. The drillability of rock is directly related to drilling speed V, vibration acceleration a, and vibration frequency f. Theoretical research on short-distance geological prediction of borehole drilling in tunnel face is completed on this basis. A set of while-drilling monitoring equipment is developed and applied to pneumatic rock drill. While-drilling equipment can collect the real-time data of drilling speed V and vibration acceleration a of the drilling machine. The data is collected based on the analysis of drilling rate V and vibration acceleration a. The quantitative relationship between rock mass level and drilling information is established. Through application in supporting engineering, a standard database of rock antidrilling coefficient of different levels of surrounding rock based on the rock type of quartz sandstone is preliminarily established. This database is better than the geological report of the excavation site.