Research On The Evaluation Of Geological Environment Carrying Capacity Of Shenmu City

Geological environment carrying capacity is a vital component of resource and environment carrying capacity,which has important guiding significance to the development and utilization of regional resources and environment,and the spatial layout of engineering construction.In this paper,the geological environment carrying capacity of Shenmu city is evaluated by means of data collection,field investigation,laboratory experiment and modeling analysis.The main results acquired are as follows:(1)The evaluation index system of collapse and landslide susceptibility indexes were produced by random forest model.The success rate and prediction rate of the model were0.929 and 0.864,respectively,and the index range of landslide susceptibility was 0,0.98.Natural breaks method was used to divide the grade of susceptibility into [0,0.10),[0.10,0.25),[0.25,0.41),[0.41,0.62)and [0.62,0.98],which represent the susceptible grade of very low,low,middle,high and very high,respectively.The numbers of collapses and landslides in the above categories were 0,21,30,67 and 82,and account for 34.46%,16.59%,18.64%,18.86%and 12.46% of the study area,respectively.(2)The evaluation index system of ground collapse susceptibility was constructed by the conditioning factors of coal seam thickness,burial depth,overlying strata thickness and lithology,and weights of the above indexes were calculated by principal component analysis with the weight of 0.26,0.31,0.36 and 0.07,respectively.The ground collapse susceptibility index interval was [0,0.94] and divided into five categories by natural breaks method point method as very low,low,middle,high and very high with the susceptibility index intervals of[0,0.10),[0.10,0.28),[0.28,0.46),[0.46,0.76)and [0.76,0.94],respectively.The numbers of ground collapses in above categories were 0,0,3,21 and 19,and account for 19.72%,14.75%,16.63%,26.69% and 22.21% of mining area,respectively.(3)Based on the systematic analysis of 75 underground water samples,the quality grades of shallow groundwater in study area is given priority to class ? class and class ?,no class?shallow groundwater.The distribution of class?shallow groundwater is widespread,of which is concentrated in hilly region and the western desert region in southern,accounting for92.57% of the study area.Class?shallow groundwater is mainly distributed in the middle and upper of Kuye river and its tributaries,accounting for 5.6% of the study area.Class ?shallow groundwater is mainly distributed in the local area of the middle and upper Kuye river and its tributaries area,accounting for 1.45% of the study area.Class ?shallow groundwater is mainly distributed in local area of tributaries of the upper Kuye river,accounting for 0.38% of the study area.(4)Based on systematic analysis of 305 soil samples,the quality grades in the study area only have class ? and class ? soil,no class?soil.Class?soil mainly distributed in the western desert region and southern hillside area,accounting for 56.37% of the area in the study area.Class ? soil mainly distributed in the central and northern mining area,accounting for 43.63% of the study area.(5)The geological environment carrying capacity evaluation index system was based on the comprehensive evaluation model with the conditioning factors of collapse and landslide susceptibility,ground collapse susceptibility,shallow groundwater quality,soil environmental quality and the protection level of geological relics.Using the principal component analysis to determine index weight so as to implement the study of geological environment carrying capacity.The weight of the above indexes were 0.30,0.25,0.21,0.17 and 0.07,respectively.The carrying capacity index interval is [0.53,2.04].In addition,the natural breaks method was applied to divide the carrying capacity index interval into [0.53,1.29),[1.29,1.52),[1.52,1.68)and [1.68,2.04],which correspond to the geological environment protection zone,geological environment maintenance zone,geological environment remediation zone and geological environment development zone,and account for 5.41%,36.12%,27.34% and 31.13% of the study area,respectively.