| Rock-mortar heterogeneous structural planes are common in modern geotechnical engineering structures.The mechanical behavior of such structural planes after shearing affects the stability of related engineering projects.In prctical engineering,the contact surface of rock and mortar is often presented in irregular shapes.At present,although there are many studies on the shear behavior of heterogeneous structural planes,there are few studies on the shear behavior of irregular and rough heterogeneous structural surfaces.Therefore,this paper aims at addressing this issue and conducts research on the shear mechanical behavior of the rock-mortar rough structure surface.Three typical curves with JRC of 2.8,10.8,and18.7 were selected from the Barton joint profiles as the profile prototypes.Multiple sets of rough and planar structural plane samples were prepared by using the three-dimensional engraving technology.These structural plane samples were subjected to shear tests under 4 levels of normal stresses.The shear behavior of rock-mortar structural plane samples was analyzed.The influences of normal stress and surface the roughness on the deformation and strength characteristics and of the rock-mortar heterogeneous structural planes were comprehensively clarified.In order to further study the shear mechanism of heterogeneous structural planes,the continuous yield model(CY)within the UDEC discrete element software was employed to numerical simulated the shear process.The simulation has explored the continuous yield theory in the shear strength criterion of the heterogeneous rock structural surface.The main research contents of this study are as follows:(1)Based on three of Barton joint profiles,sets of rough heterogeneous rock-mortar structure plane samples were prepared innovatively using a three-dimensional engraving technology.Compared with the current commonly used preparation methods,this method can directly engrave rough surface on rock or mortar blocks with specified morphology.The obtained structral planes have the same morphology as natural structure surface.This newly introduced method in preparing structure plane samples is easy to operate,and it ensure that the sample have the same properties with practical engineering.(2)The shear test of the same rock properties flat structural plane was carried out to explore the shear characteristics of sandstone,granite and mortar specimens.The normal stress and shear strength of the three are in a linear relationship,moreover the sandstone and mortar resist the shear properties and compressive properties are similar,while the properties of granite are quite different from the two samples.(3)The shear test of the rock-mortar heterogeneous rough structure plane was carried out,the relationship between the shear deformation and strength of the heterogeneous structure plane and the normal stress and roughness was clarified,moreover the macro and microscopic damage characteristics of the structure plane were analyzed.The study found that the shear resistance of rock-mortar heterogeneous structural planes is between of rock and mortar structural planes of the same rock properties,and is closer to the same structural planes with weaker shear resistance.(4)Based on the continuous yield model of UDEC discrete element software,the effect of normal stress and roughness on the shear strength of sandstone-mortar and granite-mortar heterogeneous structural planes was numerically simulated.The error between the simulation result and the test result was less than 10%,which proves the practical feasibility of the continuous yield model in UDEC.The determination of the friction angle was optimized by existed studies.This method was verified by comparing the simulation results with the test results of homogeneous and heterogeneous flat planes. |
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