Suitability Evaluation Of Underground Space Based On 3D Geological Modeling

The utilization of urban underground space resources(UUSR)is one of the most effective approaches to explore urban space,to optimize urban structure,to solve city problems,to improve city management and to achieve high-quality development.At present,the evaluation of urban underground space is mainly carried out in the cities with thick Quaternary sedimentary beds,but less in the hilly basin cities with thinner sediments cover,as well as with large area of bare bedrock.Therefore,in order to support the new urbanization construction of hilly basin-city and ensure the scientific development and safe utilization of urban underground space,it is necessary to construct a suitability assessment system for the development of hilly basin-city underground space.This study relies on the comprehensive geological survey project of Wan Jiang City Agglomeration,and obtains three-dimensional geological modeling data and underground space suitability evaluation index parameters by drilling engineering,geophysical survey,field investigation,indoor test and other research methods.Using the acquired multivariate modeling data to establish 3D geological modeling,then,the suitability assessment index of underground space is identified based on the model.Negative list method and gradation to multi-objective linear weighting method were respectively used to evaluate the suitability of underground space development in the bedrock area of typical sites(0-15m)and southern town group.And the following results have been achieved.(1)According to the borehole data,geophysical profile data,field survey point data and DEM data,et cetera,we have built 3D geological models via stratigraphic modeling and lithologic modeling.Therefore,these models could reflect the geological discrepancy for the typical field,the tributary drainage basin and the southern town group.(2)Based on the visualization display and analysis of three-dimensional geological model,the suitability assessment indexes of underground space were identified and selected.Negative list method and gradation to multi-objective linear weighting method were respectively applied to evaluate the suitability of underground space development for the typical sites(0-15m)and the bedrock area of southern town group.The suitability assessment system for urban underground space in hilly basin was preliminarily constructed based on the data acquisition,three-dimensional modeling and evaluation.(3)Through the evaluation,1)149351.805 cubic meters of underground space resources with poor suitability for shallow development of typical sites(0-15m)were obtained,and532994.673 cubic meters of underground space resources could be developed.2)The suitability of the underground space of the southern town group built on the bedrock is divided into four grades: the area with great suitability is 297.39 square kilometers,the area with good suitability is 248.01 square kilometers,the area with moderate level suitability is 181.14 square kilometers,and the area with poor suitability is 95.49 square kilometers.