Identification And Evaluation Of The Underground Space Resources Of Typical Cities In The Quaternary Plain Area

The United Nations Natural Resources Committee recognizes urban underground space as a new type of natural resource.Through the utilization of underground space,a series of urban diseases such as shortage of surface land supply,traffic congestion,environmental pollution and ecological deterioration can be alleviated,which is of great significance to the sustainable urban development.However,the evaluation system of underground space resources is inadequate,and current fragmented utilization mode leads to the problem of resource waste,high development risk and adverse environmental effects.Based on the National International Cooperation Project and the Underground Space Resources Investigation Project carried out by the China Geological Survey in typical cities of the Quaternary plain area,relevant research on identification and evaluation of the underground space resources is carried out,and the results obtained can be summarized as follows.(1)A framework for the identification and evaluation of the geological environment of underground space resources is established based on the urban geological survey,and the concept of the ideal dominant layer is proposed.When applied to Danyang,it is found that the geological conditions in the northeast of the urban area and the west of Situ Town are conducive to the development of underground space,and the geological conditions in the Yunyang-Lingkou-Lucheng area are unfavorable.Layers 3-1 and 5 are the ideal layers for local underground space development.(2)Based on the identification of Quaternary sedimentary evolution characteristics,it is revealed that the variation of the sedimentary period and sedimentary facies have a macro control effect on soil parameters through the statistics of physical and mechanical indicators of more than 1,000 clay samples,which provides support for the fine understanding of soil properties.(3)Methods of geological modeling including geological interfaces,geological bodies,boreholes,and geotechnical properties are provided based on the Voxler platform.The integration of multi-source heterogeneous geological data and the threedimensional evaluation of the geological environment for underground space development are realized.(4)Under the dual constraints of the urban environment and geological environment,a comprehensive evaluation framework of underground space resources supporting the formulation of related development plans is established.When applied to Nantong,it is found that in the unstable riverbank area southwest of the main urban area,the development of underground space resources is prohibited in principle in addition to important linear underground engineering.Langshan,Jianshan and Junshan areas with good rock mass quality are special resource endowment areas for developing underground space.The areas with the highest potential value of underground space resources are distributed in nodal form around the West Ring Cultural Square Station and Qingnian Road station.The areas with greater development difficulty are distributed in the southwest of Chongchuan District and the northwest of the Development District,which are influenced by the existing facilities,protection requirements and groundwater conditions.The development type of shallow underground space mainly includes living,commercial,office and traffic facilities.The suitability of underground space development is significantly affected by social and economic conditions.Therefore,the comprehensive quality of underground space resources is highly consistent with the potential value.(5)The typical patterns of the mutual influence between multiple geological resources including geospace,groundwater,shallow geothermal energy and geomaterials are revealed,and the method for identifying potential conflicts and synergistic potentials of multiple underground geological resources at different scales are proposed.When applied to Danyang,it is found that the underground space and geological materials in area ?3,and the underground space and shallow geothermal energy in area ?3 both have good potential for collaborative development.When applied to Nantong,it is found that the construction of Metro Line 1 will need not abandon the emergency water supply function of the area.