The Study On The Stress&Deformation And The Void Of CFRD Considering The Rheological Properties Of Rockfill Material

The concrete face rockfill dam(CFRD)is one of the most competitive and promising dam type due to its advantages like economical,simply-constructed and well-adapted.But in recent years,a lot of knotty engineering problems appeared in the high face rockfill dam,such as the separation between concrete slab and cushion layer of CFRD.This paper based on the basic data of a high CFRD,used the software of ANSYS to build the model and divide the grid,utilized Duncan-Chang E-B model whitch developed by FISH language as the constitutive model of the CFRD,simulated the filling and impounding process of the CFRD by FISH function,researched the range and law of the separation between concrete slab and cushion layer by setting the contact unit between the panel and the cushion layer and analyzed the rheological deformation of the rockfill by using the Burgers rheological model as constitutive model.The main conclusions are as follows:(1)The paper analysis the stress and deformation of the CFRD during the constructing and impounding period,and draws the conclusion that the vertical deformation of the dam is mainly due to the gravity of the dam,which is rarely affected by the water load.Horizontal deformation on both sides of the dam in the construction period is increasing,which presenting as a roughly symmetrical distribution,which is greatly influenced by the water load in impounding period.Horizontal displacement of the upstream dam area decreases,and the downstream zone areas increase.(2)The paper comparativly study of the stress and deformation of the CFRD in the case of considering the rheological behavior of rockfill and in the case of not considering the rheological behavior of rockfill.there is the rheology to the CFRD during both construction period and storage period.Under the action of gravity or water load,the rheological deformation will be very fast at first,and then it flattens out,the rheological deformation will not increase indefinitely(3)The paper analyses the deformation law of feature points in different areas of the dam body.The instantaneous and creep deformation of feature point in upstream dam facing is greatly affected by water load,followed by the feature point in the middle of dam,the feature points in downstream dam facing is less affected by the water load.The instantaneous deformation of the feature point is greatly influence by its spatial position and the arrangement of the dam construction.The creep deformation of the feature point is mainly affected by the material of rockfill and the external load.(4)Because of the panel of the high CFRD stage casting,the separation between concrete slab and cushion layer of high CFRD may appear during the construction period and the storage period.It is mainly due to the weight of the heap in the construction period;while in it is mainly due to the difference of material properties between the concrete slab and cushion layer,and the rheological deformation of the heap.(5)The paper compares the deformation of the feature point of the dam in the case of changing the cushion material and not changing the cushion material.Using Hardfill material as the cushion material can reduces the separation between concrete slab and cushion layer of CFRD.The adjustment of casting height of the slab and the preloading of water storage can reduce the separation between concrete slab and cushion layer in a certain extent during the construction period.