Study On Safety Risk Identification For Metro Station Construction On The Basis Of Construction Drawings Recognition

The metro project is a high risk construction project. On the one hand the overall construction scale increases in China year after year, On the other hand metro and underground project construction safety accident occured frequently. Summarizing the current status of safety management in metro construction, there are objective reasons such as huge investment scale, fast development pace, lackage of technical and management strength, the subjective reasons that risk identification is not thorough, risk control measures is not in place are more important. How to make risk identification knowledge in the experts experience and the regulations strutured and identify the metro station construction risk automaticall by computer is a topic of greater theoretical research and engineering practice value in the situation of very scarceful of experienced technical personnel.The primary objective of this paper is to propose Safety Risk Identification System for Metro Station Construction on the Basis of Construction Drawings (SRIS). Through the study on the risk factors automatic extraction method, risk identification rules can be acquired from the standard, specification and expert experience, inference mechanism and algorithm of risk automatic identification can be designed, realizing safety risks in metro station construction can be output automatically by the engineering drawing information. SRIS can identify potential safety hazard for risk dynamic control and warning in the construction preparation period, by applying graphic recognition technology and risk identification automation technology in risk assessment process. It is one of specific application of using information technology (IT) to improve the work efficiency and accurate of the traditional risk identification process.Designing and implementing risk factors automatical acquisition. Firstly, the metro station construction safety risk and risk factors are classified. Secondly, a relation table of risk factors and engineering technical parameters which includes project characteristics information, construction technical information geology hydrological information, construction environment information, was built. At last, computer drawings recognition strategy and special algorithm were designed to capture various types of information recognition and implete engineering semantics analysis, thus completing automatic extraction of the engineering technical parameters and risk factors.Building risk identification knowledge-base based on certainty factor. Theoretical knowledge and expert experiential knowledge of metro station construction safety risk identification was summarized, The metro construction safety risk and the risk factors are structured, the acquisition process for risk identification rules, knowledge representation method and structured storage method of risk identification are interpreted, on the basis of which the knowledge database based the certainty factors has been built.Presenting two kinds of reasoning mechanism of case-based reasoning (CBR) and rule-based reasoning (RBR) hybrid pattern. According to the characteristics of the formation of risk identification rules, the rule based reasoning (RBR) based on the principle of fuzzy control is presented based on the element group retrieval reasoning algorithm and risk credibility calculation method. Summarize safety accident case of multi-level attributes, based on the case-based reasoning (CBR) and rule based reasoning (RBR) mixed mode in metro station construction safety accident database application model, and pointed out that in the premise of CBR leading RBR application method, realizes from the construction safety accident database acquisition risk identification information.Developing and applying the SRIS. The overall framework, function models and database structure were designed and analyzied. A case study of the Pangxiejia Station in Wuhan Metro Line 2 project demonstate the construction safety risk automatic identification process and risk scenario validation.