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.


In recent years, rock engineering gradually towards on the deep underground, groundwater impact on the long-term stability of the rock engineering is more prominent. Research shows that water is the important factors that influence on the rheological properties of the rocks (LIU 1994). The disturbance of surrounding rock caused by tunnel excavation give rise to change of stress states, rock mass damage gradually accumulation until produce cracks what leading to the increase of the rock mass seepage path, the cracked rock mass further produce larger crack under the action of fissure water, with the increase of time, the rock engineering may be lead to engineering accidents such as instability of surrounding rock as well as the dam failures in certain states. Therefore, the long-term stability of the rock mass engineering depends on not only the action of the rheological behavior of rock, but also considered the effect of groundwater on the rheological process.

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