| It’s important application value to study on mining groundwater hazard prevention technique after thawing and surround rock failure mechanism of air shaft wellbore using freezing method. Depended on non-freezing sinking deep of wellbore in XiaoZhuang Mine, the author caught out research work with theoretical study,FLAC numerical simulation and combining the field practice. The main conclusion as follow:(1)The construction method of Non-freezing sinking deep was used in XiaoZhuang Mine air-saft, and construction program was formulated in this paper. The program included freeze parameter, freeze-hole layout, the designing of temperature hole and hydrology hole and frozen wall formation.(2)With the FLAC, freezing air-saft surround rock failure law of wellbore was analyzed and researched.The results showed that the maximum displacement, which was 6.3mm, occured at the wellhead after shaft excavation, it could meet the shaft sinking safety regulations that must be smaller than 50 mm and the surround rock of wellbore was more stabile. In every bench height of digging and lining, the maximum displacement of borehole wall occured at the place where the one third high of excavation face from the wellhead.(3)The support program design of ventilation shaft was accomplished and some assurance measures of construction quality was formulated, which included shaft construction engineering,steel bar engineering, concrete support t and anchoring and shotcreting network support.(4)Diffusion regularity of slurry in fissure hydrodynamic was analyzed, the paper given the expression formula through regarding the reverse water diffusion distance N and Slurry diffusivity degree L as two index. The water gushing prevention programs after wellbore thawing was formulate. Practice showed that the inflow of water of air shaft after grouting was reduced from 16m~3/h to 0.1m~3/h, which could meet the relevant requirements and the water control effect was very well. |
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