Given the analysis of underground pressure, a stress calculation model of coal floor stress has been established based on a theory of elasticity. The model presents the law of stress distribution on the relatively fix...Given the analysis of underground pressure, a stress calculation model of coal floor stress has been established based on a theory of elasticity. The model presents the law of stress distribution on the relatively fixed position of the mining coal floor: the extent of stress variation in a fixed floor position decreases gradually along with depth, the decreasing rate of the vertical stress is clearly larger than that of the horizontal stress at a specific depth. The direction of the maximum principal stress changes gradually from a vertical direction to a horizontal direction with the advance of the working face. The deformation and permeability of the rock mass of the coal floor are obtained by contrasting the difference of the principal stress established from theoretical calculations with curves of stress-strain and permeability-strain from tests, which is an important mechanical basis for preventing water inrush from confined aauifers.展开更多
In order to settle the mining optimization design and safety problem of the above 1 150 m pillar of No.1 ore-body in No.H Mining Jinchuan, the lean-ore above 1 250 m, the 1 150 m horizontal pillar and the ore-body bel...In order to settle the mining optimization design and safety problem of the above 1 150 m pillar of No.1 ore-body in No.H Mining Jinchuan, the lean-ore above 1 250 m, the 1 150 m horizontal pillar and the ore-body below 1 100 m regarded as research objects based on the original design project, and nine calculation schemes on different mining sequence and different fill body strength were put forward based on cement-sand ratio of 1 : 4, 1: 12 and 1 : 24. Calculation parameters were got by the back analysis method of field monitoring data, and the FLAC2D program was applied to compute for these schemes, stress and displacement of ground settlement, shaft and stope roof were analyzed, and some conclusions were got. Results show that the intensity of filling body and the mining technique have very important effect on controlling settlement and stability of surrounding rock; Developing of lean ore have some influences to the 16th return air filling shaft, especially for 1 500--1 400 m of the shaft; The best project is the first project. This research supply some technique references and safety appraisals for the mining of lean-ore of No.II Mining Jinchuan.展开更多
Combined with the 3D FEM,end-anchored anchorage bolts were simulated by implicit anchorage bolt element.Implicit anchorage bolt elements hide in the elements of rock mass and extremely simplify the element subdivision...Combined with the 3D FEM,end-anchored anchorage bolts were simulated by implicit anchorage bolt element.Implicit anchorage bolt elements hide in the elements of rock mass and extremely simplify the element subdivision.The calculated value of an- chorage bolt stress is larger than the measured one for the most time.we further analyzed the reciprocity of anchorage bolt and rock mass,and then deduced the analytical equa- tions of anchorage bolt stress and rock mass deformation under elasto-plastic state.The results indicate that it is essential to revise the anchorage bolts stress by using the formu- las deduced when rock mass is softened or significantly deformed.Finally,a case study indicates that the calculated results agree with those measured.Some helpful methods are offerd for more accurate simulation of the support effect and anchorage bolts real stress state.展开更多
Seven schemes for the developing extension, four schemes for the mining of the whole field and five schemes for the parameter are put forward in this paper to rational choice of technical reform schemes of Mine No.1. ...Seven schemes for the developing extension, four schemes for the mining of the whole field and five schemes for the parameter are put forward in this paper to rational choice of technical reform schemes of Mine No.1. Pingdingshan Mining Bureau.On the basis of conventional technical analysis, an optimum economy-mathmetical model of the developing preparatory schemes is worked out and a synthetic optimum is carried out.展开更多
The coal-gas existing condition was ameliorated in the coal seams prone to coal-gas outburst adopting the mining method of protective strata.The gas volume and the gas pressure were reduced synchronously in the protec...The coal-gas existing condition was ameliorated in the coal seams prone to coal-gas outburst adopting the mining method of protective strata.The gas volume and the gas pressure were reduced synchronously in the protected coal seam,and the coal seam of high permeability prone to the coal-gas outburst was changed into that of low perme- ability with no proneness to the coal-gas outburst.The D_(15)coal seam was treated as the protective strata,and the D_(16-17)coal seam was treated as the protected strata in the Fifth coal mine in the Pingdingshan Coal Mining Group.The distance between the two coal seams was 5 m averagely,clarified into the extreme short-range protective strata.The numerical analysis was based on the theory of the porous media flow with the finite ele- ment method.The gas flow process and the change mechanism of the coal-gas pressure were analyzed in the process of mining the protective strata.展开更多
文摘Given the analysis of underground pressure, a stress calculation model of coal floor stress has been established based on a theory of elasticity. The model presents the law of stress distribution on the relatively fixed position of the mining coal floor: the extent of stress variation in a fixed floor position decreases gradually along with depth, the decreasing rate of the vertical stress is clearly larger than that of the horizontal stress at a specific depth. The direction of the maximum principal stress changes gradually from a vertical direction to a horizontal direction with the advance of the working face. The deformation and permeability of the rock mass of the coal floor are obtained by contrasting the difference of the principal stress established from theoretical calculations with curves of stress-strain and permeability-strain from tests, which is an important mechanical basis for preventing water inrush from confined aauifers.
基金Supported by Key Projects in the Province Science & Technology Program of Hunan (2009FJ2005)Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-year Plan Period(2008BAB32B01)Aid program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
文摘In order to settle the mining optimization design and safety problem of the above 1 150 m pillar of No.1 ore-body in No.H Mining Jinchuan, the lean-ore above 1 250 m, the 1 150 m horizontal pillar and the ore-body below 1 100 m regarded as research objects based on the original design project, and nine calculation schemes on different mining sequence and different fill body strength were put forward based on cement-sand ratio of 1 : 4, 1: 12 and 1 : 24. Calculation parameters were got by the back analysis method of field monitoring data, and the FLAC2D program was applied to compute for these schemes, stress and displacement of ground settlement, shaft and stope roof were analyzed, and some conclusions were got. Results show that the intensity of filling body and the mining technique have very important effect on controlling settlement and stability of surrounding rock; Developing of lean ore have some influences to the 16th return air filling shaft, especially for 1 500--1 400 m of the shaft; The best project is the first project. This research supply some technique references and safety appraisals for the mining of lean-ore of No.II Mining Jinchuan.
文摘Combined with the 3D FEM,end-anchored anchorage bolts were simulated by implicit anchorage bolt element.Implicit anchorage bolt elements hide in the elements of rock mass and extremely simplify the element subdivision.The calculated value of an- chorage bolt stress is larger than the measured one for the most time.we further analyzed the reciprocity of anchorage bolt and rock mass,and then deduced the analytical equa- tions of anchorage bolt stress and rock mass deformation under elasto-plastic state.The results indicate that it is essential to revise the anchorage bolts stress by using the formu- las deduced when rock mass is softened or significantly deformed.Finally,a case study indicates that the calculated results agree with those measured.Some helpful methods are offerd for more accurate simulation of the support effect and anchorage bolts real stress state.
文摘Seven schemes for the developing extension, four schemes for the mining of the whole field and five schemes for the parameter are put forward in this paper to rational choice of technical reform schemes of Mine No.1. Pingdingshan Mining Bureau.On the basis of conventional technical analysis, an optimum economy-mathmetical model of the developing preparatory schemes is worked out and a synthetic optimum is carried out.
基金the Grants of National Scientific Funds of Control Mechanism of Geologic Hazards Induced by Coal-gas(50534070)
文摘The coal-gas existing condition was ameliorated in the coal seams prone to coal-gas outburst adopting the mining method of protective strata.The gas volume and the gas pressure were reduced synchronously in the protected coal seam,and the coal seam of high permeability prone to the coal-gas outburst was changed into that of low perme- ability with no proneness to the coal-gas outburst.The D_(15)coal seam was treated as the protective strata,and the D_(16-17)coal seam was treated as the protected strata in the Fifth coal mine in the Pingdingshan Coal Mining Group.The distance between the two coal seams was 5 m averagely,clarified into the extreme short-range protective strata.The numerical analysis was based on the theory of the porous media flow with the finite ele- ment method.The gas flow process and the change mechanism of the coal-gas pressure were analyzed in the process of mining the protective strata.