Influence of mineral composition and grain size on mechanical properties of marble
To understand the effect of mineral composition and grain size on mechanical properties of rock better,the basic data of mineral composition,mineral micro-mechanical properties,grain size and shape of four kinds of marble are obtained in this paper.Then their strength parameters,deformation properties and failure modes are tested for further analysis.The results indicate that:(1)The strength of Chenzhou,Fangshan,Carrara and Hezhou marble decreases while their ductility increases in sequence,that is,the strength and brittleness of dolomite marble is greater than that of calcite marble.(2)Considering only the effect of grain size,the strength and brittleness of rock decreases with increasing grain size.However,when considering other factors(mineral composition,micro-mechanical properties)together,it is possible that rocks consisting of larger grains present a higher strength and more brittle behavior.(3)The cohesion of rock is positively and linearly correlated with uniaxial compressive strength,while it is weakly correlated with tensile strength.(4)The ratios of uniaxial compressive strength to tensile strength are significantly different from that predicted by the extended Griffith theory,while the ratios of crack initiation stress to tensile strength maintain around 7-12.(5)During triaxial compression test,the confining pressure fluctuates slightly above the target value,and the overall synchronization exists between the variation of the confining pressure and the axial stress.The results not only enhance the understanding of mineral grain size effect and enrich the theoretical knowledge of rock mechanics,but also provide a large number of basic data for further marble engineering evaluation and calculation analysis.
rock mechanicsmarblemechanical propertiesgrain sizemineral compositionvariation of confining pressure
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万方数据
