Deformation Calculation Of The High Core Dam Based On Generalized Plasticity Model

A series of high dams are designed and planned in the western region.The high core dam which shows good performance and strong adaptability gets great promotion and application.But the monitoring data of many core dams shows that the large settlement is induced during the initial impoundment and the late operation.Because of the uplift force and the wetting during the reservoir filling,which leads to the fact that the entire upstream shell has a large settlement.Rheological deformation of the rockfill occurs during the construction and impounding,which will exist for several years after the completion.The uneven settlement caused by the different rheological properties of the rockfill and the core wall will easily lead to the crest cracking,even the failure of impervious core.On the other hand,the constitutive model parameters of feasibility study is acquired by the laboratory test,whose calculating result is often different from the measured data because of the scale effect.What's more,the calculation based on laboratory tests can only be a reference after the dam is built.The earthquakes in the western region occurs frequently and the real stress and strain state of the dam is the foundation of dynamic analysis.Therefore,the influence of wetting and rheology needs to be taken consider in,after which the rockfill's constitutive model parameters is inversed based on the monitoring data.Then the dynamic analysis is performed.Only that can the dam seismic behavior be rationally evaluated.There is a phenomenon that the static constitutive model and the dynamic constitutive model of rockfill widely applied in the engineering field are not consistent.But the generalized plastic model improved by Dalian University of Technology can perfectly solve the problem,which completes the static and the dynamic analysis by the same set of parameters.According to the monitoring data,thesis applies the generalized plastic model improved by DUT,the Li Guoying rheological model and the Shenzhujiang humidification model for joint inversion analysis to obtain the corresponding constitutive model parameters.Considering of the difference between laboratory materials and on-site rockfill and the influence of humidification and rheology,three different calculating conditions are designed for static analysis.The content and main conclusions are followed.(1)The three constitutive model of the rockfill are applied for joint inversion analysis based on the time-history curve of the measuring point's settlement.The invered settlement and the measured of the monitoring point are well fitted during every period,which indicates that the joint inversion analysis can simulate the filling and impounding of the dam well.(2)The inversed curve and the test curve of the generalized plastic model improved by DUT are compared.Different calculating conditions which take the humidification and rheology as the control variables in the addition are designed for static analysis.Under the same confining pressure,the stress-strain curve obtained by the inversion is significantly higher than the simulated curve,while the volume-strain curve is lower than the simulated curve.The inversed curve compared with the simulated curve shows obvious softening and dilatancy.The static calculation results show that the deformation calculated by the inversion parameters without considering of humidification and rheology is smaller than the deformation calculated by the test parameters,but the deformation which takes consider in humidification and rheology is greater than the deformation calculated by the test parameters.(3)Based on the static calculation result of the joint inversion,the dynamic analysis which uses a set of the generalized plastic model parameters is performed.The acceleration amplification factor at the top area of the dam reaches a higher level,which shows the typical whiplash effect.The maximum values of horizontal permanent deformation and vertical permanent deformation occur at the top of the downstream.The seismic safety of the dam is within the controllable range.