Analysis Of Fire Evolution Mechanism In Highway Tunnel And Research On The Application

In recent years,with the rapid development of highway tunnel construction,the frequency of tunnel fires has gradually increased.Highway tunnel fires not only pose a serious threat to life and property safety,but also reduce people’s trust in tunnel safety and cause adverse social impacts.Due to the characteristics of long depth and strong sealing,the fire evolution characteristics of highway tunnels are more significant.Therefore,taking the subsea tunnel of the Hong Kong-Zhuhai-Macao Bridge as the research object,the thesis analyzed the evolution mechanism of highway tunnel fire by numerical simulation,and studied the fire hazard assessment of highway tunnel and the formulation of emergency evacuation plan.The main work is as follows :(1)The evolution law of highway tunnel fire was analyzed and the combustion model was established.The FDS(Fire Dynamics Simulator)software was used to carry out numerical simulation experiments on tunnel fires of different scales.After preprocessing the experimental data,the evolution law of tunnel temperature,CO concentration and visibility under the condition of ventilation failure was analyzed from two aspects of time and space.Then,taking the vehicle combustion in the tunnel as an example,combined with the real combustion experimental data,the combustion and smoke diffusion model in the tunnel was established by using Gaussian process regression and other methods,and the model application and evaluation were carried out.(2)The comprehensive hazard assessment system of highway tunnel fire was constructed.Comprehensively considering the impact of road tunnel fire on personnel,tunnel structure and environment,the first-level index and second-level sub-indicator were set,and the method of hierarchical weight evaluation was used to construct a tunnel fire comprehensive hazard assessment system and carried out example application.When studying the effects on people,the rules of tolerance to CO and temperature in people of different ages were explored.In the study of the impact on the tunnel structure,the damage of the temperature of the fire scene to the pipe joints and tunnel cables of the immersed tunnel was analyzed.When studying the impact on the environment,the AQI index was used to reflect the air pollution caused by CO,and the corresponding relationship between visibility and driving risk was established.(3)Study and formulate emergency evacuation plan for highway tunnel fire.From the two aspects of equipment control and personnel evacuation,the fire emergency evacuation scheme of highway tunnel was researched and applied in examples.Firstly,the critical wind speed corresponding to different fire scales was determined by using FDS software.Comparing the smoke exhaust effects of different combinations of tunnel ventilation and smoke exhaust,the best ventilation and smoke exhaust scheme was obtained.Then,combined with the actual operation of the Hong Kong-Zhuhai-Macao Bridge,a control scheme for safety passages,variable message boards,indicator lights and other equipment was proposed.Finally,by analyzing the relationship between the human tolerance limit and the evolution of fire environment elements,the dangerous area and the available safe evacuation time under different fire conditions were obtained.Based on the actual situation of the subsea tunnel of the Hong Kong-Zhuhai-Macao Bridge,the thesis analyzed and studied the fire evolution mechanism and application of the highway tunnel,which can provide theoretical basis and technical support for the relevant units to formulate the fire assessment plan and emergency evacuation plan of the Hong Kong-Zhuhai-Macao Bridge subsea tunnel.