Research on the risk assessment method of heavy rainfall-geological hazard- flooding chain based on directed weighting network

Disasters have consistently impacted the development of human society. This research proposes a disaster chain risk assessment method based on a directed weighted network to address the increasing disaster risk in the storm-geological disaster-flood chain during urbanisation. By analysing heavy rainfall disaster cases in China over the past ten years, the paper identifies 23 key nodes to construct a disaster chain causal loop network and establishes a Bayesian network model using 20 years of historical data from Beijing. The exposure-vulnerability of the disaster-bearing body is incorporated into the assessment system, and six functional subsystems, such as electricity and traffic, are divided, and the weighted network is constructed by using improved hierarchical analysis and brittle entropy method. A three-dimensional node importance algorithm integrating node access, shortest path and global influence is proposed, and the comprehensive weights of 38 nodes are quantitatively calculated. The risk assessment method of the disaster chain with directed weighted network is obtained, and the risk value of the disaster chain in Mentougou District is 34.23. The research results break through the limitations of the traditional single-hazard and unweighted network research, and the constructed assessment model can provide a quantitative decision-making basis for urban disaster prevention and mitigation.