Method And Application Of Deformation Monitoring Index For Gravity Dam Based On Non-probabilistic Reliability

Deformation monitoring index is a key indicator for dam working status monitoring and safety evaluation.It plays an important role in predicting and warning dam safety and ensuring safe operation of dam.At present,the commonly used methods for the development of monitoring indicators are mathematical statistics and structural calculation analysis.The mathematical statistics method is used to formulate the dam body deformation monitoring index.Because the value of the dam body failure probability is empirical and the physical concept is not clear,when the dam monitoring data lacking,the proposed dam body deformation monitoring index will have a large error;Although the physical analysis concept is clear,the computational analysis method can overcome the deficiencies of mathematical statistics and does not require a large amount of monitoring data,but does not consider the uncertainty of the dam impact factor.The non-probabilistic reliability method can realize the high precision of the gravity dam deformation monitoring index considering the uncertain factors in the dam operation process under the condition of lack of deformation monitoring data during the construction period and initial completion.This paper carries out the research on "Development of gravity dam deformation monitoring index based on non-probabilistic reliability method".The main contents are as follows:(1)The advantages and disadvantages and applicability of non-probabilistic models such as interval model and ellipsoidal convex model are analyzed.Based on the characteristics of the uncertainty factors of gravity dams,an inscribed hyper-ellipsoid model describing the uncertainty of gravity dam impact factors is established.(2)The compatibility between the non-probabilistic reliability index and the probabilistic reliability index based on the inscribed hyper-ellipsoid model is studied,and the validity of using the non-probabilistic reliability index to evaluate the reliability of gravity dam is established.The relationship between the non-probabilistic reliability index and the probabilistic reliability index is theoretically established,so that the reliable target of the probabilistic target can be used to determine the reliable index of the non-probability target,which lays a foundation for the application of the non-probabilistic reliable index.At the same time,the non-probabilistic reliability indicators of the three high-level,mediumlevel,and low-level actual projects are calculated and reviewed,and the rationality of the theoretically determined non-probability target reliability indicators is empirically analyzed.(3)Established a criterion for the development of monitoring indicators based on nonprobabilistic reliability;a new method for formulating the monitoring index of gravity dam deformation is proposed,which formulates the indicators by determining the most unfavorable water depth by applying the non-probabilistic reliability analysis model,and combining with the dam deformation temperature and aging when determines the most unfavorable load combination by hybrid model.(4)The application of the non-probabilistic reliability index model of gravity dam and the deformation monitoring index formulation method,the deformation monitoring index of a gravity dam is drafted,and the comparison with the traditional deformation monitoring index formulation method shows that the non-probabilistic reliability is effective and the results meet the accuracy requirements.