基于地块概化和路网精细模拟理念的城市雨洪过程分区自适应模型

Partition adaptive model of urban rainstorm and flood process based on the simulation concept of plots generalization and road networks fine

为解决城市尺度雨洪模拟过程中常见的地块区域地形及管网资料不足、道路区域行洪与积水严重以及现有雨洪模型计算精度差或计算效率低等问题,提出基于地块概化模拟和路网精细模拟理念的城市雨洪过程分区自适应模型。对于资料不足的地块划分子汇水区单元,采用水文学概化方法计算产汇流过程;对道路区域划分精细网格,采用二维水动力学方法模拟水流运动过程;两者均与管网模型耦合连接,共同驱动管网模型进行汇流计算。以西咸新区沣西新城核心示范区为研究对象,搭建研究区域分区模型,对比分析整体区域均采用精细网格的全分布模型和整体划分子汇水区的半分布模型的模拟结果。结果表明:①分区模型综合考虑了地块管网排水与道路径流过程,可模拟出道路低洼区域在地表产汇流和管网溢流综合作用下的致涝过程,整体径流路径符合实际降雨水流运动规律;②相较半分布模型,分区模型在道路区域采用精细网格进行计算,可较好模拟道路区域的积水过程;③相较全分布模型,分区模型显著减少了计算量,在不同设计降雨下减少了28.2%~73.5%的计算耗时。该耦合模型有效地克服了数据条件和计算能力的限制,可为城市洪涝模拟提供一种新的耦合模拟思路。

To address common issues in urban catchment-scale rainfall-runoff simulations,such as inadequate topographic and drainage data,concentrated flooding on the road area,and the poor calculation accuracy or low calculation efficiency of the existing flooding models,a partition adaptive model based on the concept of plot generalization simulation and road networks fine simulation is proposed.For plots with insufficient data,sub-catchment units are divided,and the hydrological generalization method is used to calculate the runoff generation and concentration process.For the road area,fine grid division is carried out,and the two-dimensional hydrodynamic method is used to simulate the flow movement process.Both methods are coupled with the pipe network model to jointly drive the pipe network model to perform the confluence process calculation.The core demonstration area of Fengxi New Town in Xixian New Area is used as the research object to build a partition model.Besides,the full-distributed model with the study area discretized by fine grids and the semi-distributed model with the study area discretized by coarser subcatchments are applied in the same area for comparison.The results show that:①The partition model has the advantage of comprehensively considering the drainage of plot drainage and runoff process,and can simulate the inundation process in low-lying areas of road under the combined effect of surface runoff and pipe network overflow,which conforms to the actual rainfall flow motion.②Compared with the semi-distributed model,the partition model can better simulate the process of water accumulation in the road area by using fine grids.③Since the calculation task of the partition model is less than that of the full distribution model,simulation time can be reduced by 28.2%—73.5%under different return periods.The new partition model effectively overcomes limitations of data conditions and computing power,and can provide a new coupling simulation idea for urban flood simulation.