A Macroscopic and Microscopic Study on the Deformation Mechanism of Silt-structure Interface under Monotonic Shear Action
In order to explore the stress and deformation characteristics of the contact surface and the formation characteristics of shear bands during the shear process of silt-structure,a self-designed semi-mold direct shear apparatus was used to carry out the monotonic shear test of silt-structure under different normal stresses,structure roughness and water contents.The displacement field and strain field in the shear band were analyzed by the digital photographic deformation measurement technology(DPDM).Finally,PFC2D was used to reveal the influence of meso-particle migration and pore variation on the formation characteristics of shear bands during the shear process.The results showed that,during the shear process of silt-structure,the shear stress-shear displacement curve of silt was divided into three stages,i.e.,linear growth,slow growth,and stabilization.The peak shear stress increased with the normal stress and structure roughness increasing,and decreased with the increase of the water content of the sand sample.By an-alyzing the displacement field and strain field of the sand sample,it was found that a shear band with wide middle and narrow ends was formed in the sand sample above the contact surface.PFC2D simulated monotonic shear test of silt-structures showed that the for-mation characteristics of the shear band were affected by the particle migration of contact surface.The displacement and velocity of particles close to the contact surface in the shear band change were large,while the displacement and velocity of particles far from the contact surface were small.The difference of particle migration displacement and velocity at different parts of sand sample was the fundamental reason for the narrow width of the middle and both ends of the shear band.During the monotonic shear process of silt-structure,the porosity in the sand sample space was different,and the sand sample with a close distance to the contact surface and located in the middle had the smallest porosity,which confirmed the formation characteristics of the shear band.
SiltShear bandDisplacement fieldStrain fieldNumerical simulationMacro and micro vie
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维普
