The Study Of Residual Deformation Model On Rock-fill Materials

Embankment dams were mainly constructed in the southwest of China, zones where is characterized by high basic seismic intensity, complex geological conditions and rich in water resources, the earthquake damages will cause huge losses. The existing materials shows that most of earthquake damages have relationship with residual deformation, therefore we need to further study residual deformation of rock-fill materials. How can we predict the residual deformation has become a key issue of the design.At present, many scholars have made a lot of studies on the residual deformation, the main research method was to establish calculation model of residual deformation through a lot of tests, thus analyzing the calculation results of earth dams. The model considers different factors leads to obvious difference in calculation results. The model should not only consider test conditions such as vibration times, confining pressure and stress level, but also possesses a clear conception, be convenient for application and obtaining parameters. So it is necessary to establish a rational model.This paper is supported by the Natural Science Foundation of China "Study on dilatancy characteristics of rockfill and its impact on static and dynamic deformation of high rockfill dam"(No.51279025),"Study on failure mechanism and aseismic measures of concrete slab in high CFRD during strong earthquake"(No.51379028), the National Mega-project of Natural Science Foundation of China "Integration research on disaster simulation and safety control of high earth and rock dams during earthquake"(No.91215301) and Special Fund for Earthquake Research (No.201208013) and Program for New Century Excellent Talents in University " Aseismic of high earth and rockfill dam and nuclear power plant structures"(No. NCET-2012-12-0083). The study focus on the faultiness of existing models and the primary works as follows:(1) A large scale of dynamic cyclic tri-axial tests have been performed by a large scale tri-axial apparatus, whose materials were mainly taken from a proposed high CFRD. The model parameters could be obtained from these tests, which can provide basis for numerical analysis. (2) The property of dynamic Poisson’s ratio in residual deformation model was studied, the Poisson’s ratio has a wide range at the initial stage, but increases gradually to the subsequent stage along with vibration times or residual axial strain. The test results corrected by Poisson’s ratio were more reasonable. The relationship between Poisson’s ratio and test conditions was sorted out, and the distribution range of Poisson’s ratio was sorted out too.(3) The existing residual deformation models were summarized and concluded, and a new hyperbolic residual deformation model was proposed to express the relationship between residual strain and vibration times. The average main stress was introduced in residual volumetric strain relationship, while consolidation ratio was introduced in residual shear strain relationship, therefore, the hyperbolic model can reflect residual deformation of dams better.(4) The numerical analysis was performed to study the differences between modified Shen Zhujiang residual deformation model and hyperbolic residual deformation model, which can further verify the rationality of the model proposed by this paper.