基于SWMM的下穿式立交排水防涝设计研究

Numerical Simulation of Local Flooding under Overpass Drainage Using Dynamic Hydraulic Models Based on SWMM

以重庆市幸福广场下穿立交路段为例,利用SWMM软件,构建了典型下穿立交的水力模型,动态模拟了立交集水、积水、蓄水、排水全过程。模型将易涝点作为蓄水设施并采用孔口出流公式对其出口进行概化,较好地模拟了该立交积水的现状,并模拟比较下游出水为自由出流和淹没出流两种不同边界条件下的内涝程度。基于模拟结果,提出两种改造方案,分别为增设雨水口和设置雨水泵站抽排方案。模拟结果表明,单独增设雨水口对积水改善有限,设置抽排雨水泵站可明显改善积水情况。

The Happiness Square underpass in Chongqing city was taken as a typical case to study local flooding problems using the SWMM software. The low-lying area in the underpass was modelled as a storage unit and the stormwater inlet at the lowest spot was treated as an outlet to the storage unit. An orifice flow equation was used to calculate the flow-stage rating curve for the stormwater system inlet. Two downstream boundary conditions were utilized in the simulation including free flow and submerged flow. Two flood mitigation plans were proposed including adding extra storm drains and using a stormwater pump. Results showed that the former plan had limited improvement in the drainage capacity while the latter showed desirable performance.