Study On Simlar Rock Materials' Creep Constitutive Test And Realization By Flac^3d

Deformation and failure of rock projects often goes through a continuous development process, studying on rock creep characteristics is important for surrounding rock stability control. As that uniformity of natural rock mass is poor, sampling is difficult, and doing laboratory research with similar rock materials instead of original rock specimens is a more reasonable solution. A comprehensive approach combined with theoretical analysis, similar simulation test, creep test and numerical simulation is used in this paper, to study the creep constitutive of similar rock materials.Shandong Xinwen Mine-1100m level siltstone is the prototype test piece, with similar ratio 20:1. Similar simulation mold is developed through the compression amount analysis of particles. Suitable similar materials are selected, a large number of repeated ratio tests are carried out, the optimum ratio is determined and standard specimens are made. Uniaxial compressive strength of specimens is tested and the primary load of creep test is determined. The results show that, among the five groups of specimens, compressive strength of similar rock specimens is the largest when rosin alcohol solution's molar concentration is 30%, the average ultimate load is 5.20KN and average uniaxial compressive strength is 2.65 MPa. The creep primary load is decided to be 21% of ultimate load, which is 1.07 KN.The creep tests of similar rock specimens are carried out under constant temperature and humidity conditions by RLJW-2000. Results show that, the larger load, the more obvious creep deformation is, the average failure stress threshold is 92% of instantaneous intensity; when load is below the failure stress threshold, only initial creep and steady creep appeare on the curve, when load is above the failure stress threshold, the accelerating destruction stage of specimen is more obvious, with a complete three-stage creep. Custom nonlinear CYJ model is made according the creep curve, which can be transformed into linear Burgers model under certain conditions.The basic principles, steps and key technologies of FLAC3D secondary development are analyzed. CYJ constitutive equation is derived from one-dimensional to three-dimensional differential form, and is nested into FLAC30, the secondary development of FLAC3D is completed. Using CYJ model, similar rock specimen's creep characteristics are simulated by FLAC3D. Results show that, numerical simultaion is roughly in line with creep tests, CYJ model can describe rocks'three creep stages well.