不同层理红页岩微观孔隙结构表征

Characterization of Microscopic Pore Structure of Diff erent Layered Red Shales

针对贵州地区红页岩巷道软弱易变形且维护困难等问题,仅靠传统岩石力学测试提供支护依据是不够的。因此,基于低温液氮吸附设备,研究了不同层理红页岩微观孔隙结构表征,确定了不同层理对于红页岩孔隙结构的影响程度。结果表明:(1)层理角度0°、30°、45°、60°、90°红页岩试样孔容范围在0.0101~0.0135 cm^(3)/g,红页岩BET比表面积较小,为3.27~6.06 m2/g。(2)不同层理角度红页岩低温氮气吸附-脱附曲线形状整体呈反“S”形,红页岩样品的吸脱附回线与“B”类型接近,说明红页岩孔隙形态主要是裂缝形。(3)红页岩氮气吸附平均孔径随层理角度的减小而不断变大,红页岩样品大多数孔隙体积为微孔体积,其次是过渡孔体积,中孔及大孔体积基本上没有发育。研究结果可为不同层理红页岩巷道支护设计提供参考依据。

For the problems of weak and deformable red shale tunnel and difficult maintenance in Guizhou region,it is not enough to rely only on the traditional rock mechanics test to provide the basis for support.Therefore,based on the low-temperature liquid nitrogen adsorption equipment,the characterization of microscopic pore structure of red shale with different laminations was investigated,and the influence of different laminations on the pore structure of red shale was determined.The results show that:(1)the pore volume of the red shale samples with the angles of 0°,30°,45°,60°and 90°is in the range of 0.0101~0.0135 cm^(3)/g,and the specific surface area of the red shale with BET is small,which is 3.27~6.06 m2/g.(2)the shape of the adsorption-desorption curves of red shale with different laminations is consistent with the shape of the adsorption-desorption isothermal curves of the samples at each angle,which are inverse“S”.The overall isothermal curve of adsorption-desorption of the samples from different angles is in reverse“S”shape,and the adsorption-desorption return line of the red shale samples is close to the“B”type,which indicates that the pore morphology of the red shale is mainly in the form of fissures.(3)The average pore size of red shale nitrogen adsorption becomes larger and larger with the decrease of the angle of stratification,and most of the pores in the red shale samples are micropores,followed by transition pores,and the mesopores and macropores are basically undeveloped.The results of the study can provide a reference basis for the characterization and analysis of the microporous structure of red shale with different laminations.