A Study of Lift Joint Shearing Strength of RCC Dams

摘要

Roller compacted concrete (RCC) is different from conventional concrete in terms of strength property due to its layering system.Usually the lift joint shearing strength is lower than the strength of the body for RCC,so the lift joints are the controlling sections for dam's stability against sliding in most cases.Consequently,it' s worth discussing the current practice of applying the processing method for conventional concrete gravity dams to sectional design of RCC gravity dams.The paper sorts out the reliability-theory-based partial factor limit state design process according to the physical properties of RCC,focuses on the study of probability distribution pattern of RCC lift joint shearing parameters,characteristic value selection principle,material partial factor calculation and structural coefficient conversion through project investigation and research,expert assessment and statistical analyses of test data of Longtan and other existing projects,works out the equations suitable for limit state design of lift joint stability against sliding for RCC gravity dams,and carries out reliability calibration for various types of typical gravity dam sections designed by the proposed equations based on analyses of the statistical characteristics of basic variables affecting gravity dam' s reliability,determines the target reliability indicator of lift joint stability against sliding of RCC gravity dam on the basis of the resuits of analyses and calculations above,and thus judges the rationality of the proposed equations for ultimate limit state design of stability against sliding.