Nonlinear Creep Damage Constitutive Model Of The Weak Rockmass In Dam Foundation And Its Engineering Application

With the implement of exploitation of west region in our country and the structural readjustment of the electric power,numbers of high arch dams come forth.The engineering geological condition of the dam foundation is complicated,and there are lots of discontinuous weak interlayer,alteration zone and soft rock belt. Under the long time effects of excavation load, seepage flow load, temperature load and seismic load,creep deformation in weak rock of the dam foundation will affect the construction security and stability of the dam.Therefore, it's important and valuable to study of the creep damage mechanics character and engineering stability of the rock near the dam foundation of high arch dam.Based on the result of the deformation test in center hole and the bearing plate compressive creep test in site, the creep damage mechanism of rock is investigated with theoretical analysis and numerical simulation in the study.In this dissertation, the main investigation work focuses on the following aspects.Firstly, effects of weakness of the rock parameters are considered and a creep damage model which has variable parameters is proposed. In this model the creep parameters of the rock are gradually weakened, the unsteady creep parameters reflect the deterioration process of the material character directly.Secondly, the central difference equation in three-dimensional condition of this creep damage constitutive model is deduced. By adopting the secondary development routine interface of software-fast Lagrangian analysis of continua (FLAC^3D), the numerical analysis code of this creep damage model is investigated and developed using C++ and FISH.Thirdly, through a uniaxial compression numerical example, the creep damage mechanics characters of the model is analysed. The influence on the creep curve of the damage variable and the damage parameters is analyzed.Fourthly, based on this model, the creep damage mechanics parameters are got with numerical back inversion method.Finally, the excavation and creep damage stability of the slope at Dagangshan hydropower station are analyzed. The excavated distortion, character of stress, plastic zone and damage zone distribution character are achieved. The stability of the rock engineering under complex stress state is forecasted, and reasonable evaluation and suggestions of the design and construction of the slope are provided.