Safety Assessment On The Construction Plans Of Metro Station Project

The construction of the metro station has high risk, although the safety management is very strict, accidents still happen occasionally. The poor practicable effect of safety assessment of metro station construction plans, and the assessment results'difficultly making more effective decision support for the late safety construction management is one of the important factors. The reason of low quality of construction plans safety assessment is that:from the perspective of the practical work, experts participate in the metro station construction schemes safety assessment need to do a lot of analysis on the conditions of combination of the risk factors values, can make assessment of the safety risk. But the quantity of the combination of risk factor values is huge, and then the knowledge of metro station safety assessment is huge. A huge amount of knowledge is difficult to be fully grasped by the human brain, and makes artificial assessment difficult to guarantee the completely accuracy; the knowledge of safety assessment is huge, which makes risk analysis workload too large, and the low efficiency of manual assessment; due to the time limiting and the low work efficiency, assessment results have insufficient information (lack of risk evolution paths and space-time information) and can hardly be understood and comprehended by the grass-roots staff. From the perspective of theory, the metro station safety assessment knowledge is spread in the related literature, technical files and the mind of experts, and it is lack of effective mechanism to well maintain the knowledge. So the knowledge is hard to share and update in time. There has not a literature yet which has a comprehensive summary of the metro station construction safety risk and the related risk factors, and safety risk assessment rules lack a unified expression also. All these reasons above make the safety assessment of metro station construction plans exist difficulties, and affect the quality and efficiency of metro station construction safety management.To build safety assessment multidimensional database, and use information means to complete the effective management of the knowledge is an effective way to solve this problem. The thesis research and develop the safety assessment multidimensional database of metro station construction plans and the related assessment system, which use the informatization means to achieve the effective management of the related knowledge, to realize the automatic assessment, and expect overcoming the difficulties exist in the practical work, and improving the safety management level of metro station construction. In theory, at the same time, the research and development of safety assessment multidimensional database establish safety scientific data structure, the normative data standard, unified expression of rules and stable data update mechanism for the safety assessment knowledge of metro station construction plans, provide a scientific and effective means to manage the relevant knowledge, to make the safety assessment knowledge of metro station construction plans get good maintenance, share and updated in time, which help the metro station construction safety management better. Therefore, the research of this thesis has important theoretical significance and practical value.First of all, this thesis analyzes the relationship between metro station construction safety risks respectively and the construction methods and the risk control factors. According to the relevance between the safety risks and construction methods, this thesis puts forward the method of quick risk identification by the construction method information. This thesis researches the acquire methods of risk factors, and puts forward the method of acquiring the relevance of safe risks and risk factors by the way of taking the objective information as the main source. This thesis makes normative expression of the relevance between safety risks and construction methods, safety risks and risk factors, and provides a part of the normative needs of information for safety assessment multidimensional database.Then, this thesis discusses the extraction method of assessment rules for a single safety risk, and completes the building of assessment rules, which make the preparation of part data for the safety assessment multidimensional database.This thesis establishes all assessment knowledge of a single safety risk in the form of decision table. The attribute and attribute value are reduced by the method of rough set, and then the assessment rules are extracted and purified. For safety risks which have much more risk factors, this thesis makes the attribute values in the decision table fuzzy, built fuzzy sets of five decision attributes by the method of fuzzy rough set technology, and reduces the number of assessment rules. The assessment rules provide normative expression for the safety assessment knowledge, and the effective management and reuse of the safety assessment knowledge of metro station construction plans. They are the foundation of the safety assessment multidimensional database.Thirdly, this thesis analyzes the coupling relationship between safety risk events. This thesis further sorts out the coupling relations between the metro station construction safety risk events, and puts forward three categories of safety risk event, namely basic events, omen events and loss events, according to the different roles of safety events playing in the whole safety risks system. From the angle of system, this thesis researches the emergence, development and outbreak mechanism of risk events on the basis of the three categories of safety risk event. All these research provides the specific information needs for defined relationships between the safety risk events in the safety assessment multidimensional database.Fourth, this thesis studies the safety risk assessment method based on risk coupling. On the basis of fully considering the coupling relationship between risk events, the basic event assessment model,the multi-risk event assessment model and the assessment model of multi-construction sections with multi-risk events are successively studies based on system dynamics principle. The research above provides the theoretical calculation model for automatic risk assessment from the perspective of the whole project.Fifth, on the basis of above research results, this thesis establishes the safety assessment multidimensional database of metro station construction plans. This thesis designs the internal structure and each sub-library of the multidimensional database, researches the automatic assessment system based on the safety assessment multidimensional database, in order to realize the automatic assessment work, and then develops the expression form of the safety assessment results. The expression form is displayed in the form of 'one figure and three tables'to induct and reorganize the most important information of the assessment results. The expression form is used for the displaying of assessment results for the front-line managers and the operational staff. The 'one figure and three tables' makes the assessment results to be used in practice, can really help to improve the quality and efficiency of safety management of front-line construction, and maximize the realization of the value of assessment results.Finally, this thesis completes the safety assessment of a specific metro station construction project based on safety assessment multidimensional database and the corresponding assessment system.The assessment system establishes multi-risk assessment model based on the basic event assessment rules and the coupling relationship information between the events provided by safety assessment multidimensional database, and the assessment results described the evolution of the safety risks in the whole construction process, realizes multi-risk assessment with time-space information. After compared with the expert's assessment results, it is verified that the safety assessment multidimensional database could effective manage relevant assessment knowledge, and the assessment system could improve the quality and efficiency of assessment, and overcome the difficulty in current assessment work.This thesis researches the safety assessment of metro station construction plans. It successively develops the risk identification technology based on construction method information, the assessment rules extraction technology based on the fuzzy rough set and the multi-risk assessment technology based on system dynamics, and researches safety assessment multidimensional database and the corresponding assessment system. The research of this thesis provides an effective method to manage a huge amount of safety assessment knowledge of metro station construction plans, enriches the theoretical method of the safety risk assessment of metro construction, helps to realize the automatic safety assessment, and improves the quality and efficiency of the safety assessment of metro station construction plans, and then to ensure the safety of metro construction.