建筑小区地下空间对海绵城市建设目标可达性的影响

Impact of urban underground space on goal accessibility of sponge city construction in residential area

为探究城市地下空间对海绵城市建设目标可达性的影响,以苏州市某建筑小区为研究对象,解析研究区内绿地有效性,并逐步构建低影响开发(low impact development, LID)措施布设方案,采用SWMM(storm water management model)模型模拟不同LID布置方案的径流削减效果.结果表明,地下空间顶部绿地不适宜建设集中入渗型LID措施,归为无效绿地,适宜建设LID措施的有效绿地仅占绿地总面积的38.00%;考虑到地下空间的影响,对研究区最大程度布设源头减排LID措施,仍未满足《海绵城市建设技术指南》中的75%年径流总量控制率的要求,须设置末端调蓄措施,对应的设计调蓄容量为43.6 m~3·hm~(-2);与现状相比,按照75%年径流总量控制率对应的设计降雨配套LID措施后,面对1,2,5年一遇的高强度降雨时,研究区径流总量控制率分别提升了28.3%, 25.1%, 22.2%,峰值流量分别削减了48.6%, 38.0%, 37.5%.研究结果为海绵城市建设中LID措施的规划和设计提供了技术支撑.

In order to explore the impact of urban underground space on the goal accessibility of sponge city construction,a newly built residential area in Suzhou city is taken as research area.The author analyzes the effectiveness of green space in the research area,and constructes the optimal LID(low impact development)arrangement scheme gradually.SWMM(storm water management model)is adopted to simulate the runoff reduction effect of different LID arrangement schemes.The results indicate that the green space at the top of underground space is not suitable for the construction of LID facilities with centralized infiltration function,so this part of the green space is invalid,while the effective green space for LID construction only accounts for 38.00%of the total green space.Considering the influence of underground space,adapting LID facilities controlled stormwater runoff in source can’t meet the requirement of 75%annual runoff total control rate in《Technical Guide for Sponge City Construction》.Therefore,setting the terminal storage facilities is necessary,and the design capacity of the storage facilities is 43.6 m3·hm-2 after simulation.Compared with traditional development,after LID facilities matching with design storm in the study area,when facing the rainfall with recurrence interval of 1,2 and 5 years,the volume capture ratio in the study area is increased by 28.3%,25.1%,22.2%respectively,and the reduction rates of peak flow are 48.6%,38.0%,37.5%respectively.This study provides technical support for the planning and design of LID measures in sponge city construction.