Rheological Properties And Long-term Strength Of Wulong’s Muddled Interlayer In Carbonaceous Shale

After the dam’s high water level,the reservoir bank slope is affected by the rainfall and the water level rising.Under the long-term immersion of the river water,the rock property of the reservoir is deteriorated,and it may go into unstable state.In order to predict the long-term stability of the rock engineering along the reservoir area,it is necessary to study the rheological properties of the rock under natural and saturated water conditions.In this paper,the muddled interlayer of carbonaceous shale in Wulong section of Wujiang River are studied.Based on the mechanical properties and creep regularity of carbonaceous shale muddled interlayer in natural state and saturated state,the experimental study and theoretical analysis are used to establish the nonlinear viscoelasticity model is used to simulate the rheological properties of carbonaceous shale,and the parameters of the rheological model are determined by the stepwise iterative optimization inversion method.Finally,the rheological model is derived from the rheological model Long-term strength.The main work of this paper is as follows:(1)The merits and drawbacks of several common rheological model parameter inversion methods are analyzed and discussed.(2)Taking the muddled interlayer of carbonaceous shale in Wulong area as the research object,the rock water content test,direct shear test and friction test were carried out,and the related mechanical parameters were obtained.It provides the basis for the shear rheological test of muddled interlayer in carbonaceous shale.(3)Adopts the single specimen by incremental loading test of carbonaceous shale argillaceous interlayer shear rheology tests were carried out in the natural state and saturated state,analyzed two different condition test of shear displacement-time curve,summarizes the rheological characteristics of muddled interlayer in carbonaceous shale.(4)According to the carbonaceous shale muddled interlayer with nonlinear rheological phase,nonlinear visco-plastic component,the Nishihara model is improved and the proposed nonlinear visco-elasto-plastic Nishihara model for muddled interlayer in carbonaceous shale rheological properties.Nonlinear parameter inversion was carried out by MATLAB and ORIGIN analysis software,and the rheological model parameters were determined.(5)Using the stress-strain curve method and unstable creep method two methods to determine the long-term strength of muddled interlayer in carbonaceous shale,the applicable conditions of the two methods were compared,the stress-strain curve was obtained by fitting should be the long-term strength of the long-term shear strength parameters.