| Compared with traditional Drill and Blast methods, mechanical methods have a great advantage on efficiency, cost, safety, and environmental concern. However, due to its limited capability on adapting complicated geologic condition,research for its suitability is urgently needed. Jijicao site is the object of this paper, which has been decided as one of the pre-selected areas for Chinese high-level radioactive waste repository.Mechanical excavation methods like TBM, roadheader, raise-boring machine and reaming machine have been applied extensively in tunneling for different purposes. This study focuses on the evaluation of TBM’s suitability in the site and its different zones and units, which are divided according to the lithological and structural geological conditions. Then TBM performance prediction models and abrasiveness evaluation models areapplied to different zones and units for further analysis.The main conclusions are:(1) Based on previous geological data that we have collected,like about landform, lithology,structural geology, groundwater,and in-situ stress conditions of the site, combined with geophysical exploration and two field visits and some rock tests, can help us to identify and evaluate the geological factors that may affect TBM performance.Then the evaluation of TBM’s suitability for the Jijicao site is determined.Based on borehole sample observation statistical analysis, mineral analysis and abrasiveness test, the overall abrasiveness parameters of rock mass in Jijicao site is evaluated thoroughly.(2) Classify zones and units considering various rock mass factors, such as RQD and fracture frequency, ground water and in-situ stress. Then carried out to its different zones and units evaluation.(3) According to the classification, TBM performance prediction such as NTNU and CSM models are applied to zones and units to predict advance rate, and cutter life are evaluated through mineral microscopy and Cerchar abrasiveness tests. |
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