铁道标准设计2024，Vol.68Issue(3)：56-64,9.DOI:10.13238/j.issn.1004-2954.202208230005
晶体粒径对花岗岩力学特性影响规律的试验研究
Experimental Study on Grain Size Effect on Mechanical Properties of Granite
摘要
Abstract
Grain size is spatially and variably distributed in rock and rocks with different grain sizes vary in mechanical properties.To study the grain size effect on rock mechanical properties,the shallow weakly weathered granite along a railway line in Southwest China is selected as the research object.The granite is divided into 4 groups based on the grain size:coarse-grained,medium-coarse-grained,medium-fine-grained and fine-grained granite.Stress-strain response characteristics of granites with different grain sizes are studied by triaxial compression tests,and the variation of strength,stiffness and failure characteristics with grain size is analyzed on this basis.Finally,the grain size effect on the macroscopic mechanical properties is discussed with the help of granite microstructure images.The study shows that:(1)For granites in the same area,those with smaller grain sizes have larger peak compressive strength and corresponding axial strain.The peak compressive strength and corresponding axial strain of fine-grained granite are about 1.5 to 2.2 times and 2.1 to 1.6 times of those of coarse-grained granite respectively.(2)The shear strength and stiffness of granites increase gradually with the decrease of grain size from coarse to fine,where the cohesion increases from 13 to 32 MPa,the internal friction angle increases from 45.2 to 52.5°,the deformation modulus increases from 1.0(normalized)to 1.7 to 2.5,and the Poisson's ratio decreases from 0.29 to 0.22.(3)Granites with different grain sizes vary in microstructure.The compactness of grains and the cementation between grains in fine-grained granite are greatly better than those of coarse-grained granite.关键词
弱风化花岗岩/晶体粒径/微观结构/三轴压缩试验/应力-应变曲线/强度/刚度Key words
weakly weathered granite/grain size/microstructure/triaxial compression test/stress-strain curve/strength/stiffness分类
交通工程引用本文复制引用
杨闯..晶体粒径对花岗岩力学特性影响规律的试验研究[J].铁道标准设计,2024,68(3):56-64,9.基金项目
中铁第四勘察设计院集团有限公司科研课题(2020K043) （2020K043）
