各向异性层状千枚岩渗透率及有效孔隙率试验研究  

Experimental study on permeability and effective porosity of anisotropic layered phyllite

作　　者：王伟[1,2] 陈超维 刘世藩 曹亚军[1,2] 段雪雷 聂文俊[3] WANG Wei;CHEN Chaowei;LIU Shifan;CAO Yajun;DUAN Xuelei;NIE Wenjun(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210024,China;Institute of Geotechnical Engineering,Hohai University,Nanjing 210024,China;Sinohydro Bureau 6th Co.,Ltd.,Shenyang 110013,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210024 [2]河海大学岩土工程科学研究所,江苏南京210024 [3]中国水利水电第六工程局有限公司,辽宁沈阳110013

出　　处：《岩土工程学报》2024年第2期445-451,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金面上项目(12072102);江苏省六大高峰人才项目(JZ-008);江苏高校“青蓝工程”项目(苏教师[2020]10号)。

摘　　要：采用岩石全自动三轴伺服仪和气体渗透装置,对一种致密的各向异性层状千枚岩开展了气体渗透率及有效孔隙率试验,研究常规三轴压缩和围压循环加卸载2种应力路径下,气体渗透率、有效孔隙率随层理倾角及偏应力的演化规律。结果表明:围压相同时,岩样的初始气体渗透率k0随着层理倾角β的增大呈“W”型变化,在β=45°时取最大值;在围压循环加卸载过程中,气体渗透率先随围压的加载而减小,后随围压的卸载而增大,卸载时的气体渗透率小于加载时的渗透率;层状千枚岩有效孔隙率和气体渗透率呈指数关系;平行于层理方向的气体渗透率远大于垂直于层理方向的气体渗透率;岩样有效孔隙率和气体渗透率随偏应力变化经历初始压密阶段、线弹性阶段和塑性变形阶段,随着偏应力的增大,岩样有效孔隙率和气体渗透率先减小,接着保持稳定,最后快速增大,并在岩样应力-应变曲线斜率接近于0时达到最大值。The experiments on gas permeability and effective porosity of layered phyllite specimens are conducted by using a rock automatic triaxial servo and gas permeability panel.Two stress paths of conventional triaxial compression and confining pressure cyclic loading and unloading are set up in the experiments.The evolution rules of gas permeability and effective porosity with bedding dip angle and deviatoric stress are studied,respectively.The results show that under the same confining pressure,the initial gas permeability k0 changes in a"W"shape with the increase of the bedding angleβ,and reaches the maximum value atβ=45°.During the confining pressure cyclic loading-unloading process,the gas permeability decreases with the loading of the confining pressure,then increases while unloading.The gas permeability detected during unloading is smaller than that during loading.An exponential relationship is observed between the effective porosity and the gas permeability of the layered phyllite.The gas permeability parallel to the bedding direction is much greater than that perpendicular to the bedding direction.The variation of the effective porosity and gas permeability with deviatoric stress undergoes initial consolidation stage linear elastic stage,and plastic deformation stage.With the increase of the deviatoric stress,the effective porosity and gas permeability of rock specimens decrease first,then keep stable,and finally increase rapidly,and reach the maximum when the slope of stress-strain curve is close to zero.

关 键 词：层状岩石 各向异性 气体渗透率 有效孔隙率 常规三轴压缩 围压循环加卸载 

分 类 号：TU443[建筑科学—岩土工程]