Study On Safety Evaluation And Prevention Control Technology Of Near-water Ramp

Groundwater disaster is a common geological hazard in water-rich underground engineering,which affects the construction of underground engineering and threatens the safety of personnel and equipment.Mine flooding accidents are frequent in China,surface water and high pressure groundwater rush into underground working space through a certain channel,affecting the normal production of mines and even causing major accidents such as flooded Wells.The normal production of water-rich metal mine is greatly restricted by water.Therefore,it is necessary to study and analyze the excavation safety of roadways near water-rich strata and the control of groundwater.Taking the auxiliary ramp near confined aquifer of Luohe iron mine as the engineering background,a combination of field test,laboratory test,theoretical analysis and numerical simulation was used to study this research.Based on site investigation,the confined aquifer is no source of water supply has been clear about.Though the basic physical and mechanical tests,physical and mechanical parameters of surrounding rock are learned.Established the simplified mechanical calculation model under different position of ramp and confined aquifer,the theoretical thickness of water-inrush resistant rock strata has been calculated by using mechanics of materials,structural mechanics and elastic mechanics.Through COMSOL Multiphysics numerical simulation software,considered the mutual influence of mining and groundwater seepage,the thickness of water-inrush resistant rock strata under different positions between confined aquifer and ramp is analyzed.By using COMSOL Multiphysics,the curtain grouting water prevention method is optimized and analyzed for the curtain radius.The main research contents and results are as follows:(1)According to the engineering geology and hydrogeology conditions,it can be concluded that the ramp passes through complex strata,and the groundwater is mainly confined water of secondary quartzite with pore water pressure up to 1.4 MPa?5.2 MPa and basically no water supply.According to in-situ core-taking and laboratory tests,there are a large number of iron ore crystals,primary cracks and impurity interlayers associated with the surrounding rock,and the mechanical properties of the rock are uneven,so there is a great risk of water inrush in the ramp.(2)Simplified the water-inrush resistant rock strata between the ramp and the aquifer into an elastic beam and plate model,and the theoretical value of the water-inrush resistant rock strata thickness is obtained when the aquifer is located at different positions of the ramp with using material mechanics,structural mechanics and elastic mechanics,etc.(3)Though COMSOL Multiphysics finite element numerical simulation software,the displacement of surrounding rock for discriminant basis,fully considered the stress and seepage coupling effect,the ramp excavation displacement of surrounding rock during the process of evolution is studied under different positions of the aquifer and the ramp.And the simulated values of the thickness of the water-inrush resistant rock strata are obtained when the aquifer is located in different positions of the ramp.(4)By using COMSOL Multiphysics,the evolution law of plastic zone,compressive stress,pore water pressure,deformation and tunnel water inflow have been anlyzed,it can be concluded that the effect to prevent and control water is better when the curtain radius greater than 4 m.Appropriate increase the radius of the curtain can improve the control effect.Excessive increase of curtain radius can not improve the control effect.There are 76 figures,23 tables and 103 references in this dissertation.