Research On Target Grouting Control And Effect Evaluation Of Composite Water Diversion Structure In Coal Mine Rich In Water

With the rapid development of China’s economy,underground engineering including coal mine engineering has entered a new stage.The increasing demand for coal increases the scale of coal mining,deepening the mining depth,and the large-scale exploitation of coal in some mining areas,and the threat of water damage is increasing day by day.Water inrush from coal floor as a type of water hazard is also a serious threat to the safe production of coal mines.The main reasons for the water inrush from the coal mine floor are the water inrush from the floor,which is caused by the position of the fracture structure,and the pressure in the mining process and the pressure of the mine will cause disturbance to the water separation structure,and the water inrush accident caused by the failure of the complete floor aquifers.The grouting project can remould the aquifer of the floor effectively.By injecting the corresponding slurry liquid,the water bearing capacity of the aquifer is reformed,the recharge and the runoff of the aquifer to the floor of the coal seam are blocked during the liquefaction and curing interaction of the slurry fluid and the surrounding rock structure,and the weak water separation rock can also be strengthened.As a result,the waterproof performance is strengthened,so grouting is a very effective way to prevent water inrush accidents,and has been widely applied to coal mine water prevention and control work.The main structure of the Fengfeng Xin’an mine field is that the main fault of the eastern boundary F₅₅ fault is convergent in the north,the south open"broom"structure,shaft area presents the multi stepped graben and horst,The small fault structure in the mine field is very well developed,the occurrence of fault is large,the formation distortion is serious,and the coal and rock are very broken.Besides,the Ordovician limestone aquifer is rich in water and has good runoff conditions.The geological and hydrogeological conditions are very complicated.Due to the existence of faults,the structural fissure of aquifers and aquiclude under the floor is developed,and complex composite water guide structure is formed,which poses a great threat to the safety production of the mine.Take the 112121 working face grouting project in Xin’an mine as an example,Based on the analysis of the natural geography,engineering geology,hydrogeological data and previous research results of the study area,the complex hydrogeological conditions in the working face are analyzed in this paper,and the multi dimension analysis of the composite water diversion structure is carried out,the rapid identification of water inrush is helpful to the rapid discovery of water guide channel,the application of adaptive technique of multi material mixing with clay in normal position of Xin’an mine,the application of segmented target grouting technology in Xin’an mine is studied,a geographically weighted regression analysis model is built,and a grouting evaluation method based on fuzzy mathematics is put forward.The main research of this paper is as follows:（1）The strata uncovered in the mining area are:Ordovician,Carboniferous,Permian,Triassic,Tertiary system and Quaternary strata in turn from old to new,the faults in the mining area are very developed.There are 3 small folds,and no magmatic rocks are found in the mining area.The main source of groundwater recharge is atmosphere precipitation and valley bed leakage in some area.The groundwater runoff is controlled by the formation,geological structure and topographical factor on the whole,only a small area is affected by the hydrodynamic condition of the groundwater.The overall flow of Ordovician limestone water flows from west to east.There are two main ways of discharge including natural and artificial discharge,the main water filling source in the mining area including surface water,goaf water,water aquifer of coal strata and Ordovician limestone water.The main channel of water filling is water carrying fault fracture zone,poorly closed drilling,mining fissure and unproved shaft in small coal mines.（2）Under the 112121 working face of Xin’an Coal Mine distributed by Ye Qing,Shan Fu Qing,Daqing three layer thin limestone aquifer and coal measure strata basement Ordovician limestone strong aquifer.There are three faults F₁,F₂ and F₅ in the 112121 working face have been found use the comprehensive analysis of results of geophysical exploration,drilling,roadway exploration,water release test and water dynamic monitoring,these 3 faults are both tensile and torsion normal faults,according to geophysical and drilling data,there are 4 anomalous areas of water rich and 2abnormal tectonic zones in the study area,which are formed by the extension of the F₂and F₅ faults to the working surface.The results of underground geophysical prospecting and the existing geological data show that the local area of the Ye qing limestone and Shan fu qing limestone are hydraulically connected through the vertical development of the primary fissure,and the aquifers of the Shan fu qing limestone aquifers slowly recharge the Ye qing limestone,and the top Ye qing limestone aquifuge primary fractures also have a certain degree of development.Meanwhile,according to the underground drilling results,water can be found in the upper 1.75¹9.1m range of Ye qing limestone,which can prove the development of primary cracks in the aquifers.（3）The rapid and accurate determination of the source of water inrush is realized by using the new type of automatic water collection and analysis device combined with the analysis of comprehensive water temperature and water level method and hydrochemical analysis method.According to the reconstruction effect and hydrological characteristics of each aquifer under the 112121 working face,water inrush source is quickly determined by the method of water level,water temperature discrimination and simple hydrochemical analysis,according to the source of the water inrush,surface water,underground goaf water and atmospheric water can become the source of water inrush.Atmospheric water usually as a soft water with low salinity and low hardness.The surface water is basically silt suspended and turbidity because of its existence.In addition,there are plenty of organic matter and bacteria in both atmospheric and surface water,which can be used as a basis for judging its existence.As the complexity of the chemical composition of the water inrush water source of the mine,it is necessary to take a variety of comprehensive evaluation methods to judge,goaf water is mostly strong acid water.Water bursting has the characteristics of large instantaneous water and strong destructiveness.Usually,it has no connection with other sources of water,and it will weaken rapidly after water bursting.Through comprehensive analysis data of drilling,drainage test and water dynamic monitoring results,it is identified that the water diversion channel is mainly concentrated near the middle part of the F₂ fault.（4）Combined with the analysis of the geological survey of the 112121 working face of Xin’an mine,the optimization of the grouting material,the solidification mechanism of the slurry and the cost and price of the material,a unique adaptive technology has been used to select slurry materials during Xin’an mine grouting,called adaptive technology using mixed multi materials with clay in normal place.This technology is to make full use of the clay in the original area of the mining area and the traditional cement and water glass and other grouting materials to mix together to form one or more grouting liquid.According to the situation of the water injection area and the water output,the reasonable grouting material is selected for subregional and segmented grouting.Xin’an mine chooses clay cement paste and cement water glass as grouting material.（5）Combined with the idea of targeted therapy,an advanced cancer cell treatment method in medical field,a new technology of segmented targeted grouting in roadway is studied.The segmented target grouting in the laneway means that in the course of the construction of the alley and the inclined alley（well）,it is inevitable to drill through the directional drilling technique in the roadway,and then prepare the corresponding slurry according to the rock characteristics of the corresponding grouting layer.The size of the slurry adapted to the corresponding formation conditions is used in the way of progressive subsection grouting to fill the cracks or pores in the formation by filling the grouting holes into the formation,so as to achieve the purpose of plugging the water.Finally,the tunneling and the coal seam recovery work are carried out.（6）The correlation analysis of the traditional grouting amount,water output and the effective water insulation thickness of the coal seam floor is based on the least square method,but the regression relationship between them will change with the different location of the observation points.The GWR model of grouting volume,water output and effective water insulation thickness of coal seam floor is established.This model can embed the spatial location of data into the regression coefficient,so it can not only describe the relationship between the grouting quantity,the water output and the effective water insulation thickness of the coal seam floor,but also reflect the spatial variation characteristics of the data.The geo-weighted regression modeling method is easy to operate and can directly and intuitively express the spatial non-stability.Furthermore,the estimation results of the coefficients have a clear analytical expression and can be visualized on the geographically.The results show that there is a good correlation between the grouting quantity and the effective water separation thickness of the coal seam floor.There is a strong correlation between the grouting quantity and the output water,and the correlation between the north of the mining area and the south is gradually increased with the change of the space,and there is a certain correlation between the grouting amount and the effective water insulation thickness of the coal seam floor.The correlation is relatively weak with the correlation between the amount of water and the amount of grouting.In space,the correlation gradually decreases from the north of the mining area to the south,and the correlation between the water output and the effective thickness of the coal seam floor varies with the space.（7）The idea of fuzzy mathematics is to describe and model a large number of fuzzy concepts and fuzzy phenomena in the real world by precise mathematical means,so as to achieve the purpose of proper processing.Fuzzy mathematics is based on things that are uncertain.The emergence of fuzzy sets is the need for mathematics to describe complex things.The hierarchical structure model of grouting effect evaluation index system is established by fuzzy mathematical analytic hierarchy process（AHP）,and each evaluation factor is quantified.Fuzzy comprehensive evaluation method is used to evaluate the two and first grade index factors.Through the analysis of the evaluation results,the evaluation criteria for the 4 antiprojection effects of excellent,good,medium and poor are established.A comprehensive evaluation system for the effect of vertical grouting.The evaluation system and grade standard are used to evaluate the effect of grouting on the 112121 working face of Xin’an mine.It is found that the evaluation grade of the grouting reinforcement effect is good,the effect of grouting reinforcement is good,the hydrogeological conditions around the working face of the grouting project have changed greatly.The groundwater has been effectively controlled and the grouting effect has been effectively controlled.The fruit is expected.After the actual grouting of the working face,the situation is basically consistent with the evaluation results,and the change of grouting effect evaluation from qualitative,empirical to scientific and semi quantitative is preliminarily realized,and the research results can be popularized and applied in similar projects in the future.