为应对日益严重的城市内涝，提出了一个耦合管网-地表-路网的机理模型与网络分析模拟评估框架，旨在评估和量化内涝下交通路网的性能变化情况，并揭示网络在时域扩张和拓扑几何上的变化，以支持内涝应急规划和城市韧性建设。武汉市的案例结果表明，在20 a一遇的降雨期间，仅37个关键路段（占总路段约6%）受到影响，就导致整个网络的平均出行时间增加至其原有的508%，相当于网络整体半径增大约700 m。结果还表明40 min内的短途出行受内涝影响最严重。研究使用旅行时间膨胀率与贝蒂数量化了少数关键路段会导致整个网络出行效率急剧下降和几何结构显著恶化的现象，同时揭示了城市内涝对交通影响的滞后性特征，指出网络旅行时间的持续增加在降雨结束后仍然存在，且可能比内涝过程中更加严重。研究结果为城市洪涝应急管理与交通韧性提升提供了关键技术支撑，为制定有效的抗涝应急策略提供了具体的量化依据。

[Objective] With urban flooding getting more frequently，assessing the resulting disruption of traffic networks is essential for urban resilience and emergency planning. This study develops a tightly coupled modeling and evaluation framework to quantify how urban flooding affects road network performance over time. The aim is to capture not only localized flooding impacts but also the system-wide and delayed effects on traffic efficiency and network structure. [Methods] An integrated framework was established by coupling a one-dimensional drainage model （SWMM），a two-dimensional surface flooding model based on Cellular Automata （CA），and the microscopic traffic simulation platform SUMO （Simulation of Urban Mobility）. The proposed Urban Road-masked Cellular Automata-SWMM coupled model （URCA） enables bidirectional interaction between underground pipe flow and surface road inundation at minute-level time steps. Exchange flows between the drainage system and road surface are calculated through manholes and gullies using modified hydraulic equations. Runoff from sub-catchments is simulated within SWMM，while road-related surface flow is represented in the CA model，which incorporates land-use-based infiltration，Manning-based routing，and adaptive time stepping for numerical stability. Simulated water depth on road grids is translated into traffic control rules in SUMO using predefined depth thresholds that trigger speed reduction or road closure，ensuring dynamic feedback between flood evolution and traffic redistribution. The road network is represented as a weighted directed graph integrating static road attributes and dynamic traffic indicators. Flood impacts are evaluated using average travel time increase （T_E%），OD-based time expansion rates，network coverage，and the 0th Betti number to quantify changes in connectivity under different time budgets. The framework is applied to a 3.89 km² urban area in Wuhan under a 20-year return-period rainfall event. [Results] Model calibration shows stable hydraulic performance，with a mass balance error of 2.97% and a Nash-Sutcliffe efficiency of 0.88. Under the 20-year rainfall scenario，flooding produces strong nonlinear traffic impacts. Although only 37 road segments （approximately 6% of 618 links） are significantly inundated，the average network travel time increases to 508% of the baseline level，equivalent to an effective network radius expansion of about 700 meters. This indicates that limited localized flooding can induce substantial system-wide degradation. Travel time exhibits multiple peaks during and after rainfall，with the maximum delay occurring after rainfall cessation，demonstrating a clear lag effect. Time-budget analysis shows that approximately 12 additional minutes are required to achieve baseline coverage，corresponding to a time expansion factor of 2.23. Network coverage declines sharply during critical periods，while Betti-0 analysis indicates increased fragmentation，especially within shorter time budgets. Trips within 40 minutes are the most affected. A small number of fully blocked or severely congested links account for most of the performance decline. [Conclusions] Urban flooding can cause significant increases in travel time，structural fragmentation of road networks，and delayed peak disruption after rainfall ends. A limited proportion of critical links can trigger large-scale performance degradation，and short-distance travel is particularly vulnerable. By tightly coupling drainage and traffic processes and integrating functional and structural network indicators，this study provides a comprehensive approach for assessing flood impacts and supporting resilience-oriented urban planning.