Study On Gypsum's Creep Properties And Its Room And Pillar's Long Term Stabality

Creep property is one of the most mechanical characteristics of rock, which is closely related to the long-term stability and safety of geotechnical engineering. In this paper, integrated approaches of laboratory tests, theoretical analysis and numerical simulation are adopted to study gypsum's creep properties, and its room and pillar's long-term stability is also analyzed. A series of important guiding significance research results could be obtained.The basic mechanical properties of gypsum are studied with uniaxial tension and uniaxial compression tests. The feature of stress-strain curve and failure law are analyzed in detail. Besides, the basic physical and mechanical parameters of gypsum are obtained, which can provide scientific evidence for the creep tests and numerical simulations.The creep properties of gypsum are studied with uniaxial compression tests. The creep mechanical parameters of gypsum, same time strain curves feature and creep damage law are analyzed in laboratory creep tests. Based on the instantaneous elastic, viscoplastic and viscoelastic's characteristics joined in gypsum creep deformation, the modified Burgers model is used for describing the gypsum's creep properties. The creep mechanical parameters of creep model are identified by linear regression analysis from the tests date. Based on this, through the modified Burgers model numerical simulation, the comparing result indicates that the modified Burgers model can well describe the mechanical properties of gypsum, and the regression parameters also can well incarnate creep test deformation feature.Based on the previous modified Burgers model, the creep properties of gypsum standard specimen are discussed under triaxial compression by applying numerical simulation method. The reflected feature of numerical simulation results in every creep stage by numerical simulation is basically consistent with rock basic creep law. The result indicates that studying gypsum's creep properties under three dimensional stress states is feasible by applying the previous modified Burgers model. Through uniaxial compression creep numerical simulation experiments on different structure plane under big scale, the result indicates that structural specialty has a strong influence effect on the rcheology form. It not only influences the gypsum's creep strength, but also plays a controlling role to creep damage states of gypsum. Considering the rheological deformation characteristics after room excavation, room and pillar of 4301 working face in Luneng Taishan Gypsum Mine is carried out the numerical simulation calculation by using the previous modified Burgers model. The law of stress and deformation are analyzed under time action. The long computational results, comparing with the static analysis date in instantaneous excavation and field monitoring result, hereby, some important conclusions to the designing and construction of room and pillar could be obtained...