Study on the influence of water content on creep characteristics of silty mudstone rock under water immersion
Mudstone has the characteristics of low strength and easy water softening,which has great influence on the long-term stability of engineering rock mass,especially in the water-rich mudstone strata.Few corre-sponding studies have been reported.Therefore,it is urgent to further study the creep characteristics of mud-stone with water.In this paper,stepwise loading creep tests of mudstone samples with different initial water content under natural and water immersion conditions were conducted to study the influence mechanism of water on the creep characteristics of rock mass.Combined with the generalized Kelvin model,a creep damage evolu-tion model considering the deterioration effect of water content was established.The new model was embedded in FLAC3D finite different code to realize the programming of the model.By comparing with the numerical creep deformation of mudstone under different conditions and the experimental results.The research shows that with the increase of water content,the creep strain of rock mass increases and the long-term strength decreases.Compared with that in natural condition,the long-term strength deterioration of soft rock becomes more serious in water immersion condition.In addition,the larger the initial water content,the smaller the influence of im-mersion conditions on it creep deformation.The deterioration effect of rock mass due to water is defined as the damage factor of creep parameters.The damage factor increases with the increase of water content.The numer-ical simulation results of the creep damage constitutive model considering water degradation are basically consis-tent with the indoor test results,which verifies the rationality of the new model.
mudstonecreep characteristicsimmersed conditioncreep experimentwater deterioration effectcreep damage constitutive model
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