Study On Creep Model Of Shuibuya Flint Limestone

A large number of engineering cases show that the creep property of rock is an important factor affecting the long-term safety and stability of rock mass engineering,and it is also the main reason for the deformation and instability of rock mass engineering.Therefore,In thispaper,taking the flint limestone of Shuibuya Hydropower Station as the original rock sample,the deformation and failure characteristics of flint limestone under conventional compression conditions are carried out by means of laboratory test,theoretical analysis and numerical calculation.Study on linear Viscoelastic creep constitutive model and correlation of parameters of flint limestone under creep conditions.The main contents of the study are as follows:1)The conventional uniaxial and triaxial compression tests of flint limestone samples were carried out.The compressive strength and stress-strain curves of flint limestone under different confining pressures are discussed,and the peak stress of flint limestone samples under different confining compressive stresses is linearly fitted by numerical analysis.Under the condition of conventional compression and unloading,the failure characteristics of flint limestone samples are systematically analyzed.Through the conventional uniaxial and triaxial compression mechanical tests,the basic mechanical parameters of flint limestone samples are obtained,which provides the basic test parameters for the next step of uniaxial loading and graded unloading creep test of flint limestone samples.2)The creep tests of the prepared flint limestone samples under uniaxial loading compression and triaxial graded unloading path were carried out.The axial deformation and failure characteristics of flint limestone under uniaxial loading and triaxial graded unloading creep are analyzed,and the creep tests under different graded unloading rates are based on the axial deformation and failure characteristics of flint limestone under uniaxial loading and triaxial graded unloading creep.The relationship between the confining pressure and the graded unloading of the specimen when the final failure occurs is discussed.The creep tests under uniaxial loading compression and triaxial graded unloading path are carried out,which lays a foundation for further research on creep constitutive model of flint limestone.3)In this paper,the Burgers body is used to describe the linear viscous elastic creep deformation characteristics of flint limestone under uniaxial loading and triaxial graded unloading creep conditions.based on the basic theory of the original model,The Burgersbody model is modified and improved.Based on the experimental data obtained from the creep test of flint limestone,the parameters of the Burgers body model and the improved Burgers body model are identified respectively,and finally it is concluded that the simulation effect of the improved Burgers body model is more accurate.The conclusion that the linear viscous elastic creep deformation characteristics of flint limestone can be better reflected.