岩土工程学报2024，Vol.46Issue(1)：131-139,9.DOI:10.11779/CJGE20221286
不同冲击气压下煤样动态剪切强度的长径比效应
Length-diameter ratio effects of dynamic shear strength of coal samples under different impact air pressures
摘要
Abstract
Five sets of coal samples with a diameter of 75 mm and length-diameter ratios of 0.20,0.27,0.33,0.40 and 0.47 are subjected to dynamic shear tests under varying impact air pressures with a Φ50 mm-split Hopkinson press bar(SHPB)experimental system.The impact air pressures on the dynamic shear strength of coal samples and the length-diameter ratio effects on the dynamic shear strength and loading rate of coal samples are investigated,and a theoretical model is established for the length-diameter ratio effects.The experimental results demonstrate that:(1)The dynamic shear stress time curve of the coal samples can be divided into four stages:initial rise,linear increase,slow rise and fall in stress.(2)The dynamic shear strength and loading rate of coal samples are positively and linearly correlated with the impact air pressures,but there are differences in the magnitude of increase for different length-diameter ratios.As shown by the fact that the smaller the length-diameter ratio of the coal samples,the greater the increase in dynamic shear strength and loading rate at the same impact air pressure increment.(3)The dynamic shear strength and loading rate of the coal samples are both related to the length-diameter ratio,and exhibit positive and negative length-diameter ratio effects at lower ones of 0.25 and 0.35 MPa and higher ones of 0.45 and 0.55 MPa,respectively,and the impact pressures with the least effects of the length-diameter ratio are determined by ANOVA to be 0.376 MPa.(4)A theoretical model for the effects of dynamic shear strength length-diameter ratio on the coal samples under different impact air pressuress is established,and a theoretical model for the effects of loading rate length-diameter ratio is derived from the loading rate effects,and the reasonableness and accuracy of the proposed model are verified.关键词
煤/长径比效应/动态剪切强度/加载率/敏感性Key words
coal/length-diameter ratio effect/dynamic shear strength/loading rate/sensitivity分类
建筑与水利引用本文复制引用
王磊,陈礼鹏,袁秋鹏,焦振华,刘怀谦..不同冲击气压下煤样动态剪切强度的长径比效应[J].岩土工程学报,2024,46(1):131-139,9.基金项目
安徽省科技重大专项项目(202203a07020010) （202203a07020010）
安徽省教育厅协同创新项目(GXXT-2020-055) （GXXT-2020-055）
国家自然科学基金青年基金项目(52204083) （52204083）
