复杂应力状态下土料三轴渗透试验  

Triaxial test study on the permeability of soil under complex stress state

作　　者：凌华[1,2] 张胜 敖大华 王芳 韩华强[1,2] LING Hua ZHANG Sheng AO Dahua WANG Fang HAN Huaqiang(State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute ,Nanjing 210029, China Key Laboratory of Earth-Rock Dam Failure Mechanism and Safety Control Techniques, Ministry of Water Resources ,Nanjing 210029, China Power-China Guiyang Engineering Corporation Limited, Guiyang 550081, China)

机构地区：[1]南京水利科学研究院水文水资源与水利工程科学国家重点实验室,江苏南京210029 [2]水利部土石坝破坏机理与防控技术重点实验室,江苏南京210029 [3]中国电建集团贵阳勘测设计研究院有限公司,贵州贵阳550081

出　　处：《河海大学学报（自然科学版）》2017年第5期451-456,共6页Journal of Hohai University(Natural Sciences)

基　　金：国家自然科学基金(51679149)

摘　　要：为研究高土石坝坝体内土体单元在复杂应力状态下的渗透性能,在中型三轴仪上对同一土料场3种不同级配土料进行三轴渗透试验。试验围压分为5级(100 k Pa、400 k Pa、800 k Pa、1 200k Pa和2 000 k Pa),每级围压下分4种应力水平(0、0.2、0.4和0.8),当试样在初始应力状态下变形基本稳定后,采用常水头法测试试样的渗透系数。试验结果表明:级配是影响渗透系数的重要因素,相同应力条件下土料粉粒和黏粒含量越高,渗透系数越小;随围压和应力水平的提高,土料的渗透系数逐渐降低;粉粒和黏粒含量越低、大颗粒含量越高,围压对土料渗透系数的影响越显著;对于不同级配相同密实度试样,应力水平对渗透系数的影响程度基本一致。在分析渗透系数随围压和应力水平变化规律的基础上,建立了能描述复杂应力状态条件下土体渗透系数的经验公式。To study soil permeability of soil element within the high earth-rock dam under complex stress state, medium-sized triaxial tests are carried out on the medium-sized triaxial apparatus for three kinds of soils with different gradations from the same material site, which incorporates five levels of confining pressure （ 100 kPa, 400 kPa,800 kPa, 1 200 kPa and 2 000 kPa） , with each being consisted of four stress levels （0,0.2,0.4 and 0.8 ）. The permeability coefficient of soil sample is determined by using constant-head test method when the sample deformation is basically stable in the initial stress state. The test results show that, the coefficient of permeability is largely influenced by soil grading. Under the same stress state condition, the coefficient of permeability appears to decrease with the increase of silt and clay contents. Moreover, this coefficient of permeability is gradually reduced by the increased confining pressure and stress level, the effects of confining pressures on the coefficient are remarkably intensified by a lower contents of silt and clay and higher content of soil with large particle. For soil samples with different gradations and the same compactness, the effects of stress levels on the coefficient of permeability are basically the same. Based on the analysis results of the coefficient of permeability varying with the confining pressures and the stress levels, an empirical formula is finally established to describe the the permeability coefficient of soil under complex stress state.

关 键 词：复杂应力状态 三轴渗透试验 中型三轴仪 渗透系数 围压 应力水平 颗粒级配 常水头法 

分 类 号：TU411.4[建筑科学—岩土工程]