Site Selection Suitability Evaluation Of Underground Engineering Based On Remote Sensing And GIS Technology

Underground engineering originates from human exploration of underground space.It not only expands the space for human activities,but also has advantages of seismic resistance,concealment and confinement.Traditional underground engineering site selection through ground survey requests huge investment of manpower,material and time.It's also limited by terrain and transportation.Meanwhile,discrete survey result is difficult to reflect the overall principle of underground engineering site selection in the region.Currently site selection based on remote sensing and GIS has attracted more and more attention of researchers.Supported by the project of China Geological Survey Bureau,this paper has carried out remote sensing information extraction and standardization for underground engineering site selection index through remote sensing and GIS.Taking Ji'an area of Tonghua in Jilin province as the research target,the suitability of underground engineering site selection was evaluated comprehensively,and a comprehensive understanding of the background of underground engineering site selection in this area was formed.With regard to remote sensing evaluation of suitability,according to technical requirement of underground engineering site selection,this paper selected geological structure,rock mass basic quality and rock weathering degree as the evaluation index of stability;and selected terrain gradient,ground height difference and vegetation coverage as the evaluation index of safety conditions.In the evaluation of transportation conditions,the distance between grade highways and the distribution density of water area were selected as two indicators.Meanwhile,the type of groundwater storage was taken as the evaluation index of groundwater conditions.Based on above,comprehensive evaluation index system of remote sensing was established.Analytic hierarchy process(AHP)and index standardization method were used to further process each index.The relationship between each index and underground engineering site selection was sorted out,and the suitability evaluation model was established.The extraction of relevant index elements and the generation of thematic maps are studied in this paper.Based on the domestic ZY-3 DOM data the information of stratum lithology,geological structure,groundwater occurrence type,surface water body and road network was obtained by remote sensing visual interpretation.The vegetation coverage extraction based on NDVI was researched through quantitative inversion over Landsat 8 OLI remote sensing image.Based on domestic ZY-3 DSM data,the best statistical window for determining the topographic fluctuation degree by means of change point analysis was researched.Based on the interpretation of remote sensing information and the storage of attribute fields,the experience conversion methods of rock hardness grade,rock integrity and rock quality index for underground engineering site selection are studied.Data quantification and normalization using GIS technology was studied,and the thematic maps of remote sensing evaluation index factors were formed.Using the above models and the thematic maps of remote sensing evaluation index factors,the remote sensing assessment condition map of underground engineering site selection in the targeted location was generated by GIS model computation.By classifying the evaluation indexes,the result was graded into five levels: excellent,good,acceptable,poor and extremely poor,and sixteen preferred areas were highlighted manually,which could be classified into three situations: 1)zonal distribution along the valley;2)zonal distribution along the ridge;3)clustered distribution at the lower half of the mountain.According to the field survey results,11 out of the 15 preferred areas are suitable for underground construction,with accuracy of 73.33%.Meanwhile,based on the distribution of the preferred area and field verification,the evaluation results were ideal,which proves that the method is reliable for underground engineering pre-location.The research shows that suitability evaluation through remote sensing and GIS has advantage of broad,efficient and low-cost,which also has no limit of time and region.The advantage is more obvious in the early stage of underground engineering site selection,especially in planning and initial survey.The method also provides basis data for further detailed survey and construction and has good application prospects.