Study On The Stability Risk Assessment System Of Large-Scale Underground Caverns Group And Application

With the development of national economy and progress of the society, the under-ground engineering related with traffic construction, irrigation works and mineral resources etc. are paid attention to by people day by day. Their safety is contacted with the people life. So studying the stability and risk of the under-ground engineering such as tunnel and workshop is necessary assuredly. Compared with other rock engineering such as tunnel or slope, the research of risk analysis about under-ground workshop cavern group is absent. According to characteristics of underground engineering, the goal of this paper is researching the theory and practical method of underground cavern group stability and risk evaluation. The studying work on basic theory, key foundation and essential evaluating method are carried out. The stability of underground engineering is evaluated by means of system approach and fuzzy mathematics, and further risk evaluating system is founded to adapted to underground cavern group works. All these work can prevent the occurrence of underground accident effectively. It's important guidance to the design, construction and stability maintenance of underground engineering.Based on study of the relevant literature at home and abroad, the author analyzes the research development, results, problems, and trends in this field. The essential conception is introduced and all kinds of analyzing method are discussed. It is reasonable that the "half-qualitative half-quantitative" risk analysis method is applied on the underground works especially the cavern group engineering. Based on above analysis, the author set the research direction and content accordingly.The risk factors in underground caverns are identified. Much uncertainty in the underground hidden projects is studied and they induced the stochastic, fuzziness and dynamics in the stability risk. And then the mechanism of instability accident is researched. Risk index are confirmed that may introduce rock cavern to instability, from mechanics principles.The underground project stability criteria and a variety of criteria applied to the most intuitive are studied. Based on the most useful "relative displacement of elastic-plastic," supplemented by other criteria, the underground caverns identify indicators of risk the stability of the project "SI" is definited. Depending on the stability of the risk indicators to determine the stability of the division of the different grades of the chamber for the stability of the judge.Multi-factor model and multi-level evaluating model is construction. Fuzzy systems theory and methods applied to the stability of the project evaluation. Using AHP (AHP) impact on the stability of the chamber's analysis of the weight factors, composing the weight factor of secondary levels. When the factors that affect the stability of the caverns take place at a different value, the use of the numerical simulation of the works for a variety of intrinsic conditions. The results of the extraction of displacement has been calculated risk indicators of instability "SI". All computing results composed the "fuzzy membership database". By this way, uncertainty is expressed by the certainty. The most critical issues of caverns can be confirmed though the multi-factor fuzzy evaluation. In the future, a specific project on the evaluation of the various factors may be queried from the database. And then in accordance with the ultimate the largest membership principle, the stability of the caverns of the fuzzy level will be ensured.Subject to the findings of caverns level of stability on the basis of the totality of the caverns project risks. The establishment of a risk assessment system, using fuzzy comprehensive evaluation model will be the two major risk factors "probability" and "consequences" link. At the same time, the "degree of control" and "attention" are introduced. The four major factors establish the reasonable risk assessment model to evaluate the risk level. The evaluation of the factors will be imprecise expression and processing of digital, that leads the evaluation process more scientific. Carrying out the work on the ground floor, especially on the underground caverns, provides a new ideas and methods to the risk assessment. That also provided a reference to the risk assessment in the underground caverns.Based on the above research, the application of risk control are studied. VB language developed by Risk Analyze Software. Combined with emergency plan for emergency exercises of the Hurongxi expressway dam tunnel construction, warning mechanism is introduced. Finally, the conclusion and foreground of the engineering theory are summarized outlook. And the problem and researchful direction about the stability risk analysis in underground caverns engineering are indicated.