Study On Particle Breakage Wetting Deformation Characteristics Of Soft Rock Fillers

Soft rock has weak lithology,and it is easy to break under external force.After the water softens,the breakage phenomenon is more significant.At the same time,a large degree of wetting deformation will occur.If it is used for roadbed filler,it will easily cause pavement damage,affects road functions and driving safety.The particle fragmentation of soft rocks during wetting is an important factor affecting the wetting deformation.However,there are few studies on particle fragmentation during wetting.This article takes soft rock as the research object,analyzes the particle breakage and deformation rules of soft rock under dry and wet conditions based on indoor triaxial tests,and performs simulation experiments with PFC software.The main results are as follows:(1)With the help of electron microscope scanning and uniaxial load test,the mineral composition category and content analysis of the soft rock treated by abrasive discs were performed,and the samples were named according to the specifications.The uniaxial compressive strength of the samples was obtained and determined to be soft rocks.With the help of an indoor triaxial apparatus,a triaxial compression test was performed on the soft rock filler.The stress-strain curve trend in the dry and wet state was same basically.The material exhibited weak strain softening under low confining pressure,and the material under high confining pressure was the strong strain softens,and the bulk deformation changes from dilatation under low confining pressure to shear contraction under high confining pressure.The strength of the wetted sample decreases due to the softening of wet water.(2)Relying on the indoor triaxial test,the strain of the air-dried and wetting samples and the particle sieving results after the test are obtained.The particle breakage rate and wetting deformation under different confining pressure and stress ratios are calculated,and the air-drying and wetting conditions are obtained The soft rock particle breakage rate and the stress ratio have a hyperbolic relationship,and a normalized empirical formula for particle breakage is given.The wetting axis change of the soft rock increases exponentially as a function of the stress ratio;The ratio increases linearly.Finally,the empirical formulas of the wetting body change and the axial change are given.(3)Comparing the gradation curves of dry and wet soft rocks under the same stress conditions,it is found that the effect of submerged wetting on the gradation of soft rocks cannot be ignored;Subtracting the particle breakage rate of air-dried and wetting soft rock under the same stress conditions to obtain the wetting particle breakage rate of soft rock.The breakage rate of wetting particles shows that it increases exponentially with the stress ratio,and there is a critical value.Comparing the breakage rate of wetting particles and the amount of wetting deformation,it is found that both the axis of wetting and the volume change with the wetting breakage rate of chemical particles increased approximately linearly.(4)The PFC was used to simulate the triaxial compression deformation and particle fragmentation.The relationship between the macro and mesoscopic parameters in the numerical model is studied,and the empirical formula between the two is given.The self-made Fish language is used to achieve the gradation statistics after the compression of the numerical sample to obtain the particle breakage rate of the numerical model.Through parameter adjustment,the simulation results of particle flow software on soft rock sample deformation and particle breakage rate were obtained.At the same time,the influence of particle breakage on the internal force chain and particle displacement of the sample was analyzed by software.