Research On Risk Management For Urban Major Hazard Installations Based On GIS

City, the concentrating zone of people, industry and wealth and the core area of modern economic action, is the main place of people activity and production. City security is the foundation of all kinds of actions of living and production. With the development of social economy, the population and wealth are increasing rapidly. The importance of city security is thereby more obvious, and people focus on the city security strongly. Things go contrary to people's wishes:there are a lot of major hazard installations in many cities of our country. Some major hazard installations with toxic, flammable and explosive substance have caused many catastrophic accidents, which were always fire, explosion and the leakage of toxic substance. These accidents have caused grave human casualty, property loss and environment pollution. According to corresponding authority, there are more than 800,000 casualty accidents annually in recent years, and the death toll may reach 130,000. Of all these accidents, many were caused by urban major hazard installations, which threaten the city security and living environment seriously. So, to take a scientific approach to develop and establish a harmonious society persisting in people foremost, one of the most important targets is to avoid the urban major hazard installations causing catastrophic accidents, and to solve the important and difficult problem of urban major hazard installations management.With the background, taking the management of urban major hazard installations as target, research on the risk management of urban major hazard installations based on Geographic Information System(GIS) are carried out. The risk management of urban major hazard installations includes general investigation, identification and classification of urban major hazard installations, risk assessment, emergency succoring, and distribution design and so on. On this base, the corresponding models of urban major hazard installations management and the scientific methods of risk management of urban major hazard installations were developed, which have great value in reality and research field for several aspects, such as general investigation, identification and classification of urban major hazard installations, forecasting and defending potential risk and probable accidents of urban major hazard installations, rapid and efficient emergency succoring after accidents happening, avoiding fire, explosion and the leakage of toxic substances caused by major hazard installations, decreasing the loss of people and economy adequately, establishing harmonious society which persist in people foremost and carrying out the society which developed safely and scientifically.Several methods, such as investigation, theoretical study, numerical simulation and practice drilling, were used for developing the technology of general investigation, identification and classification of urban major hazard installations.With software engineering theory as guideline, visual program technology and GIS technology were used to develop the software for risk management of major hazard installations. The software is maneuverable, multifunctional and friendly in user interface. There are three main modules in the system, which are the database module, the information management module and the risk analysis module of major hazard installations. With the component GIS technology, the software can realize several functions perfectly, such as locating the appointed major hazard installation accurately, showing the three-dimensional scene, the risk emulation of the major hazard installation, showing the surrounding environment of the major hazard installation, quickly querying the available emergency aiding resource and optimizing the dispatching, offering related emergency aiding measures. The software can be a good tool for the management department to grasp the basic information of major hazard installations in the precinct, to manage major hazard installations daily and to arrange the emergency succoring.As one of the oversize cities in China, Nanjing, which is famous for its petrochemical industry, was chosen as the subject of this project. Major hazard installations in Nanjing were generally investigated in the project, and then the identification and classification were done by the software system. Positions and classes of 952 major hazard installations were collected. In the 952 major hazard installations,312 major hazard installations' attributive districts, trade classes and economical types were also obtained.The system has been successfully used in one emergency scouring drilling of accident for release of liquid chlorine tank which is a major hazard installation. During the drilling, the system assisted the director to make decisions, and made the scouring more efficiently. The success of the practice on the drilling, which was the most large-scale one in the history of Nanjing, confirmed the applicability of the system.At last, the distribution rationality of major hazard installations was also studied. And the content was divided into nine items. Combining the research results of distribution rationality of major hazard installation in Nanjing, a series of advices and measures were provided.