Research On Stress And Deformation Properties For High Clay-core Dam

In this paper , the development and major problems of earth and rock-fill dam, especially the core-wall dam are introduced and three kinds of constitutive models, such as Duncan E-v model, modified Cambridge model and Nanshui model are analyzed. Moreover, the finite element stress and deformation calculations of the "635" Clay-core Gravel Sand Dam in Xinjiang Autonomous Region and the Lubuge Clay-core Rock-fill Dam in Yunnan Province are implemented by means of the above three constitutive models. Making a comparison between the calculation results and the measured data, it is found:1. Three kinds of constitutive models can well simulate the stress and deformation behaviors of the above two dams in construction stage. The settlement and horizontal displacement resulted from Duncan model are larger than the measured data, the settlement and horizontal displacement resulted from Cambridge model are obviously less than the measured data, the calculation results from Nanshui model are better than the other two models, but still less than the measured data.2. Three kinds of constitutive models can't well simulate the stress and deformation behaviors of the above dams in storage stage. The calculated deformation of the three models is reverse to the measured data, and upstream shell and a part of core wall are obviously rising. The major reason is that the wetting deformation of upstream shell has not be considered .On the other hand, Duncan model has serious problems on loading and unloading criterion. Duncan model belongs to nonlinear elastic model; modified Cambridge model belongs to the single yield surface elasto-plastic model, these two models consider the decrease of confined pressure and average stress in upstream shell and the core in storage stage as unloading, as a result, no plastic deformation take place. However, Nanshui model is the double yield surface model, it can well avoid the above problems.3. The wetting deformation and rheology must be considered for the stress and deformation analysis of core-wall dam, the calculation results of Nanshui model thai wetting deformation and rheology are taken into account are good agreement with the measured data.