Research On Quantitative Three-dimensional Description Of Rough Surface And The Correlation Between Shear Strength And Parameter

Rock mass structure elements,there are two basic unit,namely the structure surface and structure,the structural plane occupies the dominant position,as on the surface of the structure type,the different development degree,the character and composition situation,rock mass structure type is very different.The integrity of the rock mass structural plane control and overall strength.Therefore,to carry out the structure of the mechanical parameters of shear strength research is critical to evaluate the stability of rock mass.As one of important factors affecting rock mass structural plane,roughness and shear strength is closely correlation,with the increase of roughness,shear strength is increased.Many scholars through the experimental study to establish estimate model of roughness and shear strength,but there are still many deficiencies:?1?Surface morphology is a three-dimensional structure,and now most of the evaluation method is based on the two-dimensional roughness curves,or structural plane simplified into plane,serrated,convex body,this is obviously unreasonable.Structure characterization of the surface roughness basic confined to describe two-dimensional curve method,considering the three-dimensional roughness characterization of its shape is relatively small.?2?Roughness evaluation only focus on the characteristics of the structure surface morphology,ignore some of the features of structure surface roughness,surface roughness and structural plane stress state,and is closely related to the stress direction.So the rapid evaluation on the three dimensional structural surface roughness and the estimated peak shear strength study has important academic value and engineering significance.?3?Rock similar material in the study,although on the compressive strength,some similar material has been able to cover to moderate intensity of rocks.However,in how to recast nature structural plane three-dimensional morphology research is still less.In order to study the relations that structural surface morphology and shear strength,We use of the three-dimensional laser scanning instrument,3D printer.The study of model similarity material obtained a matching scheme.Then made with structure,surface morphology and strength of shear test model,based on the structural plane indoor direct shear test and numerical simulation experimental research of the two methods to analyze the shear failure mechanism,finally,the three-dimensional grasselli estimate model improved formula is put forward,formula is more accurate and reasonable.The research work mainly in the following aspects:?1?Based on the rigid structure of the shear movement mechanism and the lithology of similar materials,developed a new type of hard rock mass structural plane simulation experiment materials preparation methods,get another with cement as the cementing materials,coarse sand and fine sand as aggregate,fine gravel aggregate,mixed with water reducing agent,silicon powder,green silicon carbide composite of high strength concrete additives such as geological mechanical model material,the material has production method is simple,raw materials easy,cheap,obtained the high ratio of strength of similar materials-m cement: m sand = 1:1.5,m cement: m = 1-0 water.3,m sand: m gravel = 4:1,water reducing agent parameter 2%,early strength agent parameter 2%,silicon powder parameter: 10%,silicon carbide parameters: 15%,the proportion plan could be used to the rigid structural plane of rock mass test personnel to provide technical reference.?2?elaborated on a hard rock mass structure surface model of the new technology for surface consistent structure,including the material selection,process,etc.,and the model of occlusion and similarity evaluation,it is worthy to spread is a reverse engineering-the structure of the new technology of surface consistent model.?3?The direct shear test and FLAC^3D numerical simulation study of structural plane shear characteristics,to summarize rock mass structural plane shear failure mode.Rock mass structural plane shear failure in the process,only occurs on the surface of some traces of sliding and destruction,the numerical simulation study also confirms this,only for the direction of the shear surface shear resistance,in addition to the direction of the shear small plane mainly shear failure,and the direction of the dorsal shear small plane mainly the tensile damage.It is concluded that the shear strength model to estimate the tensile strength of rock mass can reflect the structure more shear characteristics.?4?The test surface morphology of joints showed that a higher ratio of joint element parabola relationship effective shear angle and above the infinitesimal area combined with the total area of the joint.Based on the results of direct shear tests of several sets of joints with different shapes,this paper presents a new formula for calculating the peak shear strength of joints,which can be taken into account by the dilatancy effect.The new peak shear strength formula is in the form of Mohr Coulomb friction law and has clear physical meaning.The required parameters are determined by the joint surface topography,so the peak shear strength of joints can be predicted.