Preliminary safety and risk assessment for existing hydraulic structures: An expert system approach

摘要

This thesis describes the engineering knowledge and reasoning processes required to execute the preliminary risk assessment process for existing concrete gravity dams. The research describes the concepts of stability of a concrete dam. An expert system has been developed to contain that knowledge and is validated so that it can be used as an effective engineering decision making tool to assist in the field inspection of a dam. The expert system identifies failure modes, remedial measures, and requests additional information if required. The deterministic evaluation process is concerned mostly with the structural stability of the dam, but takes into account the hydraulic and geotechnical factors that have a direct bearing on the stability evaluation. The emphasis of the research is on the identification and computer modeling of the knowledge rather than the development of a new expert system shell. The present expert system was developed with the shell Personal Consultant Plus.;The original aspects of this research are: (1) The research identified the nature and the components of stability in such a way that an expert system could "learn" how to evaluate the stability of any concrete gravity dam in any given loading condition; (2) the expert system does not use a pre-determined fault tree for the risk assessment, because it creates the branch of the fault tree as required by the particular consultation; (3) the expert system combines the reasoning processes to conduct a qualitative evaluation of a dam and to analyze the results of a traditional quantitative engineering evaluation; (4) the methodology takes advantage of both the expert system technology and the qualitative physics and common sense reasoning approaches of artificial intelligence.;The refinement and validation of the knowledge base are done by analyzing three different dams under varied loading conditions, and comparing the expert system's results with those of independent engineering evaluations.