Research On Post-earthquake Fire Blown-up Effect Considered The Seismic Failure Of The Water Supply Network

When the earthquake happens, the lifeline systems usually destroyed and loses its service capability, meanwhile, secondary disasters occur, the lifeline system should restrain the secondary disasters from sprawling, but the lifeline system may lose its whole or partial service capability which will leads to a more destructive effect of the secondary disasters, and leads to a more serious damage, this is the so called disasters "blown-up" effect.The seismic failure of the water supply network has such "blown-up" effect on the post-earthquake secondary fire:the pipelines of the water supply network are easily damaged when the earthquake happens, and the water supply network system usually works with leakage, which leads to the service capability failure or descend. The water supply network is the main force of the fire control, the failure or descend of its service capability may leads to the sprawling the secondary fire, which can be called the "blown-up" effect of the secondary fire.So it’s necessary to research on the seismic failure of the water supply network and its impact on the secondary fire, and it can provide good decision to the water supply network fixing and fire saving. This article deeply discussed the above questions.Firstly, constructed the hydraulic computation model of the post-earthquake water supply network. Leakage and burst in the network are two main seismic damage form, define the leakage status and the burst status with the help of the concept of the pipe damage probability, and come up with an judge function of the pipe status. Analyze and modify the hydraulic computation in the two status, as to the burst model, should delete the burst pile and try the connectivity analysis again, execute the hydraulic computation process based on the new steady water supply network model; as to the leakage model, adopted a modified leakage area coefficient model to complete the hydraulic computation model of the leakage water supply network. Take an real water supply network as an example, simulate the burst and leakage status with the matlab program, calculate the hydraulic changes when the water supply network under the two status, analyze the computation with the crucial index-nodal level, leakage line.Secondary, simulate the post-earthquake secondary fire evolution process based on the Bayesian network theory, and evaluate the post-earthquake secondary fire probability affected by the water supply network failure with its reasoning function. In the construction learning stage, summarize the relevant factors of the post-earthquake fire looking up to the historical papers, combined with the index-nodal level, leakage line, mentioned in the third chapter, constructed the Bayesian network construction with D-S method, in the parameter learning stage, generate the samples with the Monte-carlo method, finally constructed the post-earthquake secondary fire Bayesian network. And then evaluate the post-earthquake secondary fire probability affected by the water supply network failure with its reasoning function:from the point of the risk, the nodal water supply capability is weaker, the probability of the fire hazard happens is greater; from the point of maximize the effect of the disaster relief, the node which is more accessible should be prior to the ones which is more dangerous.