Performance Evolution Characteristics And Safety Analysis Method Of Roller Compacted Concrete Gravity Dam

With the increasing development of rolling compaction technology in China,the number of RCC dams in service has been increasing.At the same time,many RCC dams have entered the “middle age stage” or even “aging stage”.Therefore,it is particularly important to evaluate the service performance of RCC dam at different time periods.Taking the RCC gravity dam project of a certain area as an example,the related analysis and research are carried out on the monitoring data of the dam,the variation of the material parameters,the influence of the seepage field corresponding to the stress field and the stability of the dam under the long-term service.The main contents of this paper are as follows:(1)Based on the analysis of the monitoring data of RCC dams,the statistical analysis of the deformation characteristics of RCC dams is carried out.This paper establishes a regression model for the relative displacement of RCC dams and compares the model analysis results with measured data.The established model was validated as valid.Analyzing the overall service performance of the dam under active service conditions can also lay the foundation for subsequent research and analysis.(2)Considering compaction mechanism of the roller compaction structure,the physical parameters of the roller layer and the seepage characteristics between the layers were reasonably analyzed.The method of determining the main physical parameters of the equivalent layer is proposed in this paper.Based on the analysis of the interaction mechanism between the seepage field and the stress field,a simulation analysis model for the mechanical properties of the RCC gravity dam,which takes into account the seepage between layers,was established.The influence of the seepage between layers on the structural performance of the dam was analyzed scientifically.(3)Under the influence of load and environment,the deterioration process of materials and the evolution of service performance of concrete dams are discussed.Based on the dam's apparent monitoring data,dam deformation training sample sets were obtained through structural FEA positive analysis.Then,combined with interval analysis,rough set theory and neural network theory,the interval optimization inverse analysis model of main parameters of RCC gravity dam is built.From the structural evolution mechanism level,the essential explanation is given.The inversion interval parameters can provide theoretical basis and decision support for long-term service and operation management of dams.(4)From the uncertainty of the material parameters of the dam,the parameter interval inversion is used to obtain the material parameters of the dam and the dam foundation.Based on this,the stability safety analysis model of the roller compacted concrete gravity dam based on non probability reliability is established,and the reliability of the instability of a RCC gravity dam is analyzed and predicted.It reveals the change rule of dam structure's running state,and provides pertinent technical support for later reinforcement and reinforcement time node.