Study on creep properties and constitutive model of carbonaceous slates under dry and saturated states

摘要

Moisture condition is an essential factor to mechanical properties of rock creep.Carbonaceous slates in wooden village ridge tunnel of Lan-Yu railway were taken for research object, studied the moisture condition affects the mechanical properties of rock creep through the uniaxial compressive creep tests of dry and saturated rock specimens.The test results indicated that the creep strain of saturated specimens is considerably larger than dry specimens under the same stress level.It is deformation were more than 3 times to dry specimens, and also need a long time to get into the stable creep stage.Furthermore, in terms of the creep properties of rock in dry and saturated state, put forward a nonlinear visco-plastic body, combined with Burgers rheological model, established a nonlinear damage rheological model.Meanwhile, the test results are fitted to obtain the rheological parameters of rock by taking that combined with linear decreasing weight Particle Swarm Optimization (PSO) and Levenberg-Marqud (L-M) nonlinear least squares method, fitting curves are coincide with the test curves, it shows that the proposed nonlinear rheological model is available and reasonable.