Evaluation On Geological Suitability Of Underground Space Development In Qiantang New Area,Hangzhou City

Underground space development is the best way to deal with the current shortage of space.Many cities are actively developing underground space.There is no space for shallow underground space in some developed cities.Due to the irreversibility of underground space development,aggressive development is prone to waste of resources.Therefore,it is necessary to carry out the evaluation of the geological suitability of underground space,it is an important link for the rational and orderly development of underground space,and it is also a necessary prerequisite for the scientific planning of land and space.This paper analyzes the geological conditions in the study area by collecting the geological data of Qiantang New Area.It constructs shallow,geological problems from five aspects:topographic and geomorphic conditions,engineering geological conditions,hydrogeological conditions,active faults and seismic effects,and environmental geological issues.Sub-shallow and sub-deep evaluation index system.Since underground engineering needs to be stable for a long time,this article refers to the negative list evaluation method,adding sand liquefaction,avalanches,landslides,mudslides,ground subsidence and seepage damage and other geological hazards susceptibility indicators.Traditional evaluation methods have the "barrel effect",and the weight determination process does not consider the internal differences of indicators.This article adopts variable weight analysis method and analytic hierarchy process to make mathematical corrections according to the actual quality of each evaluation unit.Finally,the grey relational analysis method is used for comprehensive evaluation in GIS software.The spatial domain of this study is below 50 m underground,and is divided into three layers:shallow(0-15m),sub-shallow(15-30m)and sub-deep(30-50m).Four suitability levels are delineated according to relevant methods: suitable(level I),relatively suitable(level II),medium suitability(level III)and poor suitability(level IV).The main evaluation results are:(1)shallow The suitability of the geological conditions of the underground space is mainly suitable,and the main restrictive factors are the water-rich aquifer and ground subsidence;(2)The geological suitability of the sub-shallow underground space is poor.Due to the complex geological conditions,the development of underground space is difficult.The main constraints include rock and soil characteristics,soft soil thickness,water richness of aquifer and seepage failure;(3)The sub-deep underground space has good geological suitability and can generally support underground engineering construction.However,as the development depth increases,the difficulty of groundwater control increases,and hydraulic conditions need to be considered when developing.At present,the development and utilization of underground space in Qiantang New Area is still at a relatively low level.This research can support the preparation of underground space planning in Qiantang New Area...