Study On The Influence Law Of Surface Subsidence On Ecological Environment In Hongqinghe Coal Mine Under Ultra-long Strike Mining Condition

The large scale and high intensity mining of coal resources have caused serious damage to the ecological environment in mining area.The mining time of ultra-long strike working face is longer than that of conventional working face,the goaf presents long strip geometric characteristics,and the roof strata structure failure characteristics and surface subsidence have their own characteristics.Therefore,the research on surface subsidence rule under the condition of ultra-long strike mining is carried out.In order to study the environmental and ecological damage characteristics of surface subsidence area,surface subsidence is used to invert the migration law of overlying strata of coal seam.It has important guiding significance to predict the temporal and s Patial characteristics of mine earthquakes.On the basis of previous studies,based on the actual surface subsidence monitoring data of the 3-1301 working face of Hong Qinghe Coal Mine,this Paper studied the surface subsidence rule under the ultra-long strike mining condition by combining the method of theoretical analysis,ABAQUS numerical simulation and decision tree prediction model,and predicted the energy of mine earthquake events according to the research results.And the following main conclusions are reached:(1)Combined with field investigation and analysis of surface rock movement observation data,the following rules and characteristics of surface movement and deformation of 3-1301 working face in Hong Qinghe Coal Mine are obtained: To form "basin",two or more tendencies on 301 face glue transported along the groove side surface subsidence phenomenon is more obvious,"U" glyph sinking,general goaf center for settlement,deformation distribution is concentrated.(2)The Abaqus numerical model is used to study the movement and deformation law of overlying rock and surface under ultra-long strike mining conditions.By comparing the stress distribution diagram and displacement diagram of coal rock under different advance distances and different mining speeds,it can be seen that with the advance of mining face,the goaf scope increases,and the surface inclined subsidence and strike subsidence increase gradually.Three small scale "basin" phenomena are formed on the surface,and the settlement value at the center increases successively.With the increase of mining speed,the stress of each rock layer increases to varying degrees.With the increase of advance distance,the area of stress sudden reduction phenomenon in the key layer becomes more extensive,and the stress drop value is lower than the minimum value in the slow mining,indicating that the overburden stress release is greater in the fast mining,which threatens the construction safety.(3)Matlab and SPSSPRO sample analysis software were used to establish an efficient and accurate decision tree model through a reasonable and reliable sample database,and test samples were used to verify the prediction model.The decision tree prediction model is used to predict 625 samples,and the value range of various Parameters under earthquake is obtained.(4)The natural environment and social environment of the study area are elaborated.The damaged area of the subsidence area is 46.35 hectares;The soil organic matter content and nutrient content decreased,and the soil fertility decreased.From 2017 to 2021,the vegetation coverage of Hongqinghe coal mine decreased by5% annually,and the medium and high vegetation coverage decreased from 28.16%in 2017 to 21.46% in 2021,making it difficult to repair.Combined with the prediction results,the ecological environment of the subsidence area,the characteristics of subsidence and the influence of surface subsidence on the ecology of the mining area are summarized,which points out the direction for the ecological restoration problem in the current price section of the region.In this study,the rules of surface subsidence under ultra-long strike mining conditions are summarized and the relation between surface subsidence and mine earthquake is established.It is intended to apply the results of the research to the prediction of surface subsidence in mining area,and provide a basis for the safety of coal mine production.