| Zhaogu complicated hydrogeological conditions,mining area coal mining under floor limestone water threat seriously.After grouting reinforcement inrush mechanis m has become the Jiaozuo such as water,fengfeng,feicheng mining area one of the key technical problems to be solved.There are many factors that can affect water inrush,including mining,the grouting,the rock mass itself nature,geological and mining characteristics,causes and mechanism of water inrush and its complex.To solve these problems,this article in jiaozuo mining area of working face water inrush is still happen after grouting reinforcement as the engineering background,the theoretical analysis,numerical simulation,field measurement,indoor experiment and similar simulation,the method of combining system grouting reinforcement working face floor water inrush mechanism is studied,and the evaluation of grouting reinforceme nt effect,form suitable for Zhao Gu coal mine comprehensive prevention and control of water technology,mainly completed the following content:(1)The influencing factors of water inrush and the characteristics of mining floor is analyzed,and the maximum damage depth of the base respectively to calculate the elastic mechanics and plastic mechanics solutions,mainly the following conclusions:(1)Summary analysis after grouting water inrush accident,realize the reasons of water inrush were 4:fault;Mining influence;The abnormal high resistance area of the prevention and control of omissions;Grouting reinforcement engineering technology.(2)Establish a semi-infinite plane body mechanics model of the distribution of the force,combined with the Mohr-Coulomb strength criterion,the maximum damage depth of the base to calculate the elastic mechanics,is as follows:(?)(3)Based on the plastic theory of slip line field,the establishment of plastic slip line mechanics model,calculate the bottom plastic mechanics solution of the maximum damage depth,and calculate the yield zone of coal seam length,as follows:(?)(2)The application of ultrasonic testing technology field detection"original rock grouting-mining influence"the entire floor in the process of different elastic modulus of rock lithology,developed a of ultrasonic probe for detecting the coal mine inclined hole protection device.And combined with field in rock specimen,rock burst and grouting filling ultrasonic detection of indoor experiments,the quantitative mastered the grouting reinforcement for floor rockmass elastic modulus increase and the mining of rock mass damage degree and the law of modulus of elasticity,and quantitative evaluation of the grouting reinforcement effect.Mainly from the following conclusion:(1)The measured results show that the grouting,rockmass elastic modulus of the overall increase.Normal section,elastic modulus of rock mass average of 232%,the mudstone elastic modulus increase degree is the largest,640%;Secondly,sandstone,is241%~241%;Limestone,the smal est is 159%~176%.The fault zone,the elastic modulus of rock mass average of 253%,the mudstone elastic modulus increased most,733%;Secondly,sandstone,is 277%~277%;Limestone,the smal est is 146%~216%.The affected by mining and elastic modulus of rock mass damage degree of differe nt lithologic difference is not big,is 21%~35%.The grouting reinforcement area after mining of rock mass damage still has a certain strength,have reinforced effect;Fault zone rock mass breakage,crack development,the original low elastic modulus,elastic modulus of rock mass after grouting are still below the normal section,is water inrush danger zone.(2)The laboratory test results show that the rock of different lithology,elastic modulus difference is very big,which biggest limestone,sandstone,mudstone minimum;And the elastic modulus decreases with the increase of crack width,but reduce the amplitude is different,the damage degree of the fissure on the elastic modulus of mudstone,the largest is 93%;Findings and the sandstone is 88%;Limestone,minim um61%rock elastic modulus increased obviously after grouting,but difficult to restore to the complete state of rock elastic modulus.Grouting on the elastic modulus of mudstone enhanced the most,225%;Findings and the sandstone is 147%~147%;Limestone,minimum 103%,realize the crack damage in rock elastic modulus and grouting for the enhancement degree and the law of rock elastic modulus.(3)Numerical integral rockmass elastic modulus obtained from field measured than indoor test results of smal er,but the elastic modulus of rock mass"strengthening-damage degree change trend".(4)For the first time before and after grouting reinforcement,inrush studies the quantitative assessment of various indicators.(3)Respectively,in the absence of fault and fault conditions,the analysis of the mechanics mechanism of the inrush,calculating the limit of floor water-resisting layer can withstand water pressure value,and to floor the limestone water inrush risk is evaluated.Based on field measurement of grouting reinforcement on the degree of enhancement floor rockmass elastic modulus,for the changes of the rock mass mechanics parameters of the grouting reinforcement quantitatively supplement and correction,to Zhaogu coal mine 11050 working face as the prototype,respectively set up without fault and fault conditions,floor before and after grouting reinforcement,the four kinds of numerical model,and contrast analysis of the coal seam floor stress distribution law in the process of mining and mining failure characteristics,mainly from the follow ing conclusion:(1)In the absence of any fault,floor water-resisting layer can withstand the limit of water pressure is:(?)(2)A fault cases,the limit of floor water-resisting layer can withstand water pressure is respectively:(?)(3)Numerical simulation results show that:in four kinds of models,backplane maximum damage depth all increase with working face advancing,but the increase rate are obviously different.In the absence of any fault,floor damage depth is less than a fault condition,shows that the influence of the fault is whole process;After grouting,base damage depth is less than before grouting,grouting reinforcement effect is better.Have faults without grouting,floor damage depth,the largest 49.8 m;Without fault grouting,minimum floor damage depth,28.6 m,are spread to L8 limestone aquifer,the results with the actual situation.Therefore,must be carried out on the floor of the grouting reinforcement,can ensure the safety of mining.(4)To Zhaogu coal mine 11050 working face as the prototype,the orthogonal experiment method,the selection of three typical factors affecting floor grouting reinforcement effect,the floor crack rate,ratio of grouting material and thickness of bottom water-resisting layer,each factor set three level,design a set of a total of 9 sets of similar simulation test,simulation mining of coal seam after grouting reinforceme nt,respectively,analyses the three factors on the depth of floor stress,displacement of floor,floor damage and floor rockmass elastic modulus these four indicators of the sensitivit y of the size and the influence law,obtained the observation index of main control factors,mainly from the following conclusion:(1)Orthogonal experiment under different combinations of the various observation index range is larger,especially the largest mining floor damage depth is 17~33m.Maximum stress is 2.7~2.7MPa;The maximal displacement of 1.1~1.9m.Mining floor strata move before die is 7.1~8.5MPa,postharvest are reduced,and 6.1~8.3 MPa.(2)Poor analysis analyzed the impact of various factors on the various observation indexes sensitivity,got the main control factors of each observation index found:floor crack rate of floor stress plays a role of master and bottom rock elastic modulus,thickness of water-resisting layer of floor displacement and floor master role,damage depth and the ratio of grouting material floor rock elastic modulus also has certain influence.(3)Floor crack rate,the greater the bottom water-resisting layer thickness is smaller,after the mining floor and floor heave of the most serious,is the key area of the grouting reinforcement.(4)Floor rock fracture development areas,after grouting reinforcement,improve rock move mould grouting make floor rock integrity good,improve the overall resistance to deformation capacity of the base plate,effectively improve the mechanical properties.After mining,rock mass was significantly lower die,show that the area is still low intensity area,after reinforcement is water inrush danger zone. |
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