Study On Rockfill Dam Seepage And Stress And Deformation Characteristics Under Extreme Damage Condition Of Concrete Face Slabs

Concrete face rockfill dam (CFRD) is one of the main types of earth-rock dam. The principle part of the dam which plays a supporting role is made of moraines and gravels and its upstream face setting concrete face plays an anti-seepage role. CFRD having many characteristics of low requirements for base, easy diversion, low cost, rapid and simple construction and so on is one of the preferred types of dam for many projects. The development trend of modern concrete rockfill dam is to build higher and higher and the size of the project is larger and larger. Therefore, to accurately predict the seepage and stress variation characteristics of rockfill dam under extreme damage is important to CFRD design and operation management.But domestic and abroad have not brought enough attention to the seepage and stress variation characteristics research of rock fill dam under extreme damage or the depth of research is very limited.First of all, this paper systemicly analyses the characteristics, causes and hazards of concrete slab under extreme damage with two constructed CFRD projects. Then, based on the equal-width slit motion law and seepage flow mechanism of CFRD, seepage flow calculation model of slab joint and slab crack, equivalent quasi-continuum seepage flow model of face slab with intensive cracks and seepage calculation model of rockfill dam under extreme damage are established. Through comparative analysis of calculation principle's similarity between seepage filed and temperature field, the feasibility of CFRD seepage field analysis with generic software ADINA 'T' module is demonstrated. Using ADINA's redevelopment platform, Duncan-Chang E-B consititutive model is added to the software's material storeroom, and the efficient approach of three-dimensional finite element calculation for CFRD stress and deformation is acquired. Based on the research and analysis of nonlinear finite element calculation, some special boundary analogy issues such as contacts, grading load, face slab cracks and joints and so on are discussed, and with the redevelopment in the ADINA software, the above-mentioned special boundary analogy is achieved. Finally, unifies the Gongboxia CFRD project, in view of normal and face slab extreme damage work conditions, CFRD seepage and stress and deformation of the three-dimensional finite element calculation is carried, and calculation results in various work conditions are obtained. With comparation analysis between calculation and actual results of seepage and stress and deformation in water storeage time, it shows that the two results tally closely. So the calculation results in this paper are reasonable and accurate.In this paper, the above-mentioned models and methods lay a necessary theoretical basis in for the research and forecasting of rockfill dam seepage and stress and deformation, and the analysis calucation achievement also has an important reference and application value to the similar projects.