Research On Surrounding Rock Controlling Under Gangue Filling And Above Confined Aquifers

Similar simulation, theoretical analysis and field measurement methods are used to study the relationship between supports and surrounding rock, estimation method of roof weighting, mine pressure behavior and backfilling's effects on floor failure regulation.With the rebound hammer, the strength of roof strata and distribution of the abutment pressure was observed. Xingtai mine 7606 filling mining working face in coal wall of spring back value of two lane increased from 0 to the peak, then down to a steady characteristics, peak point about 8 m from coal wall. Hammer in abutment pressure tests of the rebound value, compressive strength and forepole distance fitting curve results with two lane ahead of the curve of pressure on-line real-time monitoring data obtained results are basically identical. This illustrates the rebound hammer in abutment pressure test data measured by two is has certain guiding significance on the spot, can use this way to simple test abutment pressure, to a certain extent, improve the efficiency of the mine pressure observation.Research and experiment with advanced equipped with pressure sensor of filling mining hydraulic support, the two-dimensional for filling mining similar simulation experiment, the support load, the rock stress and displacement were observed. At the beginning of the study found that stents high filling supporting force and working resistance can limit deformation of roof, ensure good filling effect, thus reducing slowly sinking zone height, control the surface deformation. And points out that filling mining strata movement characteristics has significant difference with traditional longwall fully mechanized, restrictions in the goaf filling directly on the top of the deformation and subsidence and caving. Immediate roof is given priority to with fracture and caving, main roof can form bending down or fracture movement form, but not the caving height of overlying rock strata caving significantly reduced. Through the analysis of filling mining hydraulic support working resistance, found that the periodic weighting interval increase, mine pressure appear intensity is low; For filling the roof abscission layer speculum observation on the abscission layer mainly occurs within the scope of the immediate roof, the old top basic integrity, verify the theoretical analysis results.Through force analysis of waste rock filling mining stope support system, the calculation of rational support working resistance of the waste rock filling mining method. Support load of working face, mining deformation characteristics of roadway roof abscission layer and filling body analysis results and the theoretical analysis. Face middle filling rate is higher, the end of filling rate is low. Every time a small rise is not filling body stress as a result of the igneous rock roof periodic breakage, but by the roof slowly sinks gradually because of compaction filling body. When working face advance for about 30 to 40 m, working face support pressure will be significantly higher phenomenon as a whole, the reason for this was partly due to the mine roof strata pressure gradually compaction filling, filling compaction increases the roof subsidence; On the other hand is due in about 30 ~ 40 m as a basic roof collapse distance of the limits of the basic roof subsidence will speed up, part of the load borne by stent. The periodic weighting interval significantly than normal fully mechanized large time step width, compressive strength is not obvious, the reason was that the filling body slow down on the top of the old rotary sinks and bear most of the old top load, so as to alleviate the working face mine pressure appear.By filling the strata movement regularity is used to numerically simulate the analysis found that when the filling rate is 85%, the 40 m in the strata of roof subsidence is 365 mm, maximum subsidence than when the filling body elastic modulus minimum 1 GPa of strata subsidence(202 mm) largest; 70% of filling material, the 40 m in the strata of roof subsidence is 432 mm, maximum subsidence than when the filling body elastic modulus maximum minimum 1 GPa of strata subsidence(270 mm). When the advance when working face advancing to 70 m, above goaf strata vertical displacement is the largest. Vertical displacement and filling rate is 0.86, in comparison with the simulation mining of increased significantly, but smaller than all the caving method at the same time, it is inversely proportional to the vertical displacement and filling rate, the higher the filling rate, vertical displacement is smaller, the fill of the better the results. When the filling body elastic modulus is 1 GPa, strata subsidence for maximum 270 mm; 5 GPa for filling body elastic modulus, strata subsidence for maximum 213 mm; 10 GPa for filling body elastic modulus, rock strata subsidence for maximum 179 mm; Filling body elastic modulus is 15 GPa, strata subsidence for maximum 146 mm; 20 GPa for filling body elastic modulus, rock maximum subsidence is 128 mm. Can be seen from the above value of elastic modulus increased with the filling body, strata subsidence decreases, and reduce the amplitude decreases.By empirical formula calculation: xingtai coal mine 7608 working face mining depth is 366 ~ 446 m, 2 ~ 14 ° seam dip Angle is, under the condition of working face length of 80 m, floor damage depth is 7.72 ~ 10.66 m, normally the biggest damage depth position away from the level of the working face of coal wall distance under normal circumstances is 4.48 ~ 6.18 m. Actual observation base damage depth of the maximum of about 10.2 m; When the floor damage depth development to the maximum position, the maximum floor damage locations and working face of coal wall horizontal distance of about 10 m. And the results are basically in agreement with the theoretical calculation, the observation result reasonable and effective. Face plate after excavation summoned the situation due to the confined water and high levels of stress, as well as the influence of the goaf filling floor not summon very severe, working face advancing reach 1 m to 100 m when summoned the largest quantity; And the goaf filling after bottom up also have very good control effect, when the working face advancing 100 m, backplane summoned the largest amount of 16 cm. Without filling mined-out area, when the working face advancing 60 m, tension stress concentration appears in limestone, this is the main reason of the limestone; And because goaf filling, after filling body gradually by compaction, wet limestone though effective stress due to the confined water is reduced, but does not appear stress concentration, and showed the filling body to control the stress of floor strata play a role.