Mechanism Of The Rapid Interception Of The Flowing Water And The Quantitative Evaluation Of The Pre-Grouting Effect Of Water Inrush Disaster In Coal Seam Floor

After the occurrence of a water inrush disaster in a seam floor,the rapid interception of the flowing water in a water-flowing roadway by the borehole-controlled grouting can solve the difficult technical problems such as big work quantity,long construction period and being easy to induce a secondary disaster during water interception of the traditional water-flowing roadway,but still can't ensure that the water inrush disaster will not take place again in the area where a water inrush had occurred,later the work such as water interception of water-inrushing channels or water source-blocking pre-grouting governance of a water-inrushing aquifer is needed to be carried out.At present,the theoretical research on the rapid water interception of the flowing water in the water-flowing roadway by the borehole-controlled grouting legs much behind the engineering practices,it is difficult to judge the governing effect of the water interception of the water-inrushing channels or water source-blocking of the water-inrushing aquifer.Therefore to carry out the study on the mechanism of the rapid interception of the flowing water and the quantitative evaluation of the pre-grouting effect of water inrush disaster in coal seam floor is of important theoretical significance and engineering practical value.Based on the theories of the hydrogeology,hydromechanics and computer science,by adopting the methods such as analysis of the typical cases,theoretical analysis,laboratory test,physical simulation,numerical simulation and field measurement,the flowing water governance models of the water inrush disaster in coal seam floor,the mechanism of the rapid water interception of the flowing water in the water-flowing roadway and the effect quantitative evaluation of the water interception of the water-inrushing channels or water source-blocking of the water-inrushing aquifer were studied,the major achievements are as follow:(1)Considering three basic factors of mine inundation water level,water inrush and space position of mine roadway,the flowing water governing conditions of the water inrush disaster in coal seam floor were classified,and the difficulty level of different flowing water governance conditions were illustrated.According to the characteristics of the water inrush disasters during drivage and extraction in working faces,the flowing water governance models for the drivage and extraction were divided.(2)The major controlling factors and applicable conditions for the rapid interception of the flowing water by the borehole-controlled grouting with grout-conserving bags were summarized.The models of water burst and water blocking and the hydraulic models for grouting construction of the rapid interception of the flowing water in the water-flowing roadway were set up.The large-scale simulation test system of the rapid interception of the flowing water in the water-flowing roadway was developed,which may be used in the simulation test of the rapid water interception in the water-flowing roadway of 5 m wide,4 m high and flowing water flow of 2000m~3/h under conditions of different mine water flooding level and water level of different water-inrushing sources,the maximum water pressure of the water-inrushing sources may be up to 5MPa.(3)The non-interactive ratio test of gelation time,consolidation rate and stone strength for water-cement ratio,sodium silicate concentration,volume ratio of single cement grout and sodium silicate was conducted,and the optimal ratio of the borehole-controlled grouting grout to resist the flowing water washing is that W:C is 1,sodium silicate concentration is 30 Baume degree,C:S is 100:30 and 100:50,when C:S is100:30,it is used to fill inside the bags to control grouting,when C:S is 100:50,it is used to fill outside the bags to control grouting.(4)Based on the test of the physical simulation and the numeric simulation of the CFD-DEM coupling model on the rapid interception of the flowing water by the borehole-controlled grouting with grout-conserving bags,it is revealed that the rapid interception mechanism of the flowing water in the waterflowing roadway is that the grout-conserving bags can control the migration and diffusion of dual grout between the bags,accumulate and connect with the roadway roof quickly,complete part of the aggregate bedding and filling stage ahead of time,speed up the air in the roadway to quickly discharge out of the roadway,and make the water-blocking body have the performance of high resistance and weak permeability.(5)The quantitative evaluation model of the pre-grouting effect of the water interception of the water-inrushing channels or the water source blockage in a water-inrushing aquifer was set up.Combined with the practical application in grouting water-blocking engineering,the feasibility of this quantitative evaluation model was verified.