基于地质条件的海绵城市适宜设施类型选择

Selection of Suitable Facility Types of Sponge City Based on Geological Conditions

海绵城市建设过程中,根据城市所处区域的地形地貌、地质条件等特点,选择适宜的海绵城市设施类型是其关键问题之一。本研究以某航空港海绵城市拟建片区为研究对象,在广泛收集和分析研究区有关地质、水文地质资料的基础上对海绵城市建设影响因素进行分析,并建立指标评价体系;从地表适宜性、包气带适宜性以及含水层适宜性3个方面,选择7个影响因子作为海绵城市建设地质适宜性评价指标,利用层次分析法对各影响因子进行权重赋值;在对各影响因子分级评分的基础上,利用ARCGIS按照建立的指标评价体系进行加权叠加评分,根据评分结果选择海绵城市雨水管理的适宜设施。研究表明:地质与水文地质条件对雨水的入渗、地下储存和传导有显著影响,海绵城市建设应充分利用地质与水文地质条件,合理设计低影响开发(LID)工程设施的类型和建设方案;其中,包气带渗透性能和包气带厚度是海绵城市建设地质适宜性的最主要因素,决定着以雨水入渗为主要功能的LID设施建设的适宜性。

Choosing suitable types of facilities according to the topography and geological conditions is one of the important parts during the construction of sponge city.This study is based on one part of a sponge airport under construction.After a wide collection of the geological and hydrogeological data,the authors analyzed the influence factors of the construction of sponge city.From the suitability of surface,vadose zone and phreatic aquifer,seven influence factors were chosen to be the evaluation indexes of geologic suitability of sponge city construction,including terrain slop,surface permeability,aeration zone thickness,aeration zone permeability,aeration zone clay thickness,aquifer permeability and aquifer thickness.The analytic hierarchy process was used to assign the weight of each influence factor.Finally,ArcGIS was used to stack the scores through weighting by the score of each influence factor graded according to the national standard or the situation in the study area.According to the scores of each rating region,the authors suggested the suitable facility types of sponge city.The results show that geological conditions and hydrogeological conditions have a significant impact on the infiltration,underground storage,and transmission of rainwater.The geological and hydrogeological conditions should be made a full use in the construction of sponge cities to design the facility types and construction schemes of low impact development（LID）.The permeability and the thickness of aeration zone are the most important factors for the geologic suitability of sponge city construction;and both of them determine the suitability of LID facilities with rainwater infiltration as the main function.