摘要
为探究含黏土基质的土石混合体的渗透特性演化规律及其物理机制,分别对不同含石量的黏质土石混合体开展重型击实试验和三轴渗透试验。试验结果表明:对于0%~70%含石量的黏质土石混合体,击实曲线形态呈单峰状,与纯黏土类似;当含石量大于70%时,压实效果开始下降;随着含石量的增加,最优含水率持续降低,而最大干密度先增大后减小,在约70%含石量时达到最大值;当黏质土石混合体达到最优压实状态时,其中黏土基质部分的含水率不依赖于含石量而基本保持一致;含石量为0%~30%时,黏土基质达到较高的压实程度,孔隙比基本保持不变,随着含石量的进一步增加,黏土基质孔隙比逐渐增大,当含石量超过70%时,急剧增大。渗透系数随含石量的增加先减小后增大,并在30%含石量附近达到最小值。基于土石细观结构分布和黏土基质压实孔隙比演化规律,提出一个黏质土石混合体渗透路径概念模型,将不同含石量混合体试样的渗透路径划分为:低渗透性压实黏土路径、超低渗透性含砾石黏土路径、中渗透性土石结合面路径、高渗透性骨架空隙路径,较好地解释了黏质土石混合体渗透特性随含石量的演化机制。
In order to study the evolution law and physical mechanism of permeability performance of compacted clayey soil-rock mixtures, a series of dynamic compression tests and triaxial permeability tests were conducted. The compaction curves of soil-rock mixtures show obvious unimodal patterns similar to those of pure clayey soils when rock content CR < 70%. When CR > 70%, the compaction effect begins to decline. A peak for the maximum dry density of the mixtures can generally be achieved when the CR is around 70%. In addition, increasing CR will decrease the optimum water content of the soil mixtures, but this almost does not change the water content of clay matrix at the optimum compaction state. Clay matrix can be compacted to the densest state when CR < 30%, beyond which the clay matrix void ratio gradually increases. When CR > 70%, the clay matrix void ratio presents a sharp increase. The permeability shows constant or a slight decrease as the rock content increases from zero to about 30%. The lowest permeability can be achieved when CR is around 30%. Beyond this amount, the permeability coefficient increases rapidly with a further increase in rock content. Based on the soil-rock meso-structural distribution and clay matrix void ratio, a concept model for flow path in clayey soil-rock mixtures was proposed. The flow path in compacted soil-rock mixtures can be divided into four kinds: low permeability path in compacted clayey soil matrix, ultra-low permeability path in compacted clayey soil matrix with gravels, medium permeability path in soil-rock interfaces, high permeability path in skeleton voids of rock aggregates.
作者
鲁洋
刘斯宏
张勇敢
杨蒙
LU Yang;LIU Si-hong;ZHANG Yong-gan;YANG Meng(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing,Jiangsu 210098,China;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210098,China;International Joint Laboratory of Long-term Behaviour&Environmentally Friendly Rehabilitation Technologies on Dams,Hohai University,Nanjing,Jiangsu 210098,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第6期1540-1548,共9页
Rock and Soil Mechanics
基金
国家自然科学基金(No.U1765205,No.51979091)
中国博士后科学基金(No.2021M690878)
中国水利水电科学研究院水利部水工程建设与安全重点实验室开放研究基金(No.IWHR-ENGI-202006)。
关键词
土石混合体
黏土基质
含石量
压实
三轴渗透
细观结构
soil-rock mixtures
clay matrix
rock content
compaction
triaxial permeability
meso-structure
作者简介
第一作者:鲁洋,男,1991年生,博士,助理研究员,主要从事水工岩土工程和特殊岩土体力学方面的研究,E-mail:luy@hhu.edu.cn;通讯作者:刘斯宏,男,1964年生,博士,教授,主要从事土石坝工程、土工袋技术及水工岩土等方面的研究。E-mail:sihongliu@hhu.edu.cn。
