(1. School of Mechanics and Civil Engineering,China University of Mining and Technology,Beijing 100083,China;2. State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Beijing 100083,China;3. MCC Tiangong Group Co.,Ltd.,Tianjin 300308,China)
Abstract:Model test studies based on the similarity theory was conducted to solve the safety problem of frozen rock wall in the mines driving with the freezing-blasting method. The model was constructed with a ratio of 1∶15. The degree of damage of the model was evaluated by the change of the ultrasonic velocity after blasting. Three velocity sensors were placed in the slot at the top of the model,and the sensors recorded the rock vibrating velocities of the measuring spots during each blasting process. Results show that the vibrating velocity is the largest in the radical direction,medium in the axial direction and the lowest in the tangential direction. The vibration has directional difference. The damage of frozen wall exhibits an obvious cumulative effect,and the damage factors near the blasting holes are larger than those in other places. In the vertical direction,the upper end of the model is damaged most seriously. The vibration of rock satisfies Sadovski formula with the media parameter K = 57.52 and the attenuation coefficient ? = 1.74. The largest vibrating velocity is caused by the third group detonators in the differential blasting process,and the velocity of rock vibration is very different in different directions and is the largest in the radical direction,medium in the axial direction and the lowest in the tangential direction.
马芹永,蔡美峰. 人工冻结黏土可钻性试验与分析[J]. 岩土工程学报,2003,25(5):634-637.(MA Qinyong,CAI Meifeng. Experiment and analysis on drillability of artificially frozen clay[J]. Chinese Journal of Geotechnical Engineering,2003,25(5):634-637.(in Chinese))
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LADANYI B. Creep of frozen slopes and ice-filled rock joints under temperature variation[J]. Canadian Journal of Civil Engineering,2006,33(6):719-725.
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