压实黄土强度及渗透各向异性研究
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摘要
为揭示各向异性对黄土强度和水分场的影响,通过抗剪强度试验和渗透试验对压实黄土强度和渗透各向异性进行研究。结果表明:压实黄土存在强度各向异性,其垂直方向强度参数大于水平方向;压实黄土粘聚力各向异性随含水率增大而减小,干密度对压实黄土粘聚力各向异性无显著影响;含水率和干密度对压实黄土内摩擦角各向异性均无显著影响;压实黄土存在渗透各向异性,水平方向渗透系数大于垂直方向;压实黄土渗透系数随着干密度、围压的增大而减小,且增大到一定程度后变化趋于平缓;干密度、围压对压实黄土渗透各向异性都有较大影响,随着干密度和围压的增大,压实黄土的渗透各向异性会逐渐削弱。
To reveal the influence of anisotropy on strength and moisture field of loess,the strength and permeability anisotropy of compacted loess were studied by laboratory tests. The shear strength of compacted loess was studied by directly shearing tests and the permeability coefficient of compacted loess were studied by permeation tests.The result shows that the strength anisotropy of compacted loess is anisotropic. The cohesion and interior friction angle of compacted loess in the vertical direction are greater than that of the horizontal direction. The cohesive anisotropy of compacted loess decreases with the moisture content increase. The effect of dry density on the cohesive anisotropy of compacted loess is not obvious. The effect of moisture content and dry density on the anisotropy of internal friction angle is not obvious. The permeability anisotropy of compacted loess is anisotropic. The permeation coefficient of compacted loess in the horizontal direction is greater than that of the vertical direction. The permeation coefficient of compacted loess decreases with the dry density or confining pressure increase,and the change tends to be gentle when they increase to certain content. Dry density and confining pressure have great influence on the anisotropic permeability of compacted loess. The permeability anisotropy of compacted loess decreases with the dry density or confining pressure increase.
To reveal the influence of anisotropy on strength and moisture field of loess,the strength and permeability anisotropy of compacted loess were studied by laboratory tests. The shear strength of compacted loess was studied by directly shearing tests and the permeability coefficient of compacted loess were studied by permeation tests.The result shows that the strength anisotropy of compacted loess is anisotropic. The cohesion and interior friction angle of compacted loess in the vertical direction are greater than that of the horizontal direction. The cohesive anisotropy of compacted loess decreases with the moisture content increase. The effect of dry density on the cohesive anisotropy of compacted loess is not obvious. The effect of moisture content and dry density on the anisotropy of internal friction angle is not obvious. The permeability anisotropy of compacted loess is anisotropic. The permeation coefficient of compacted loess in the horizontal direction is greater than that of the vertical direction. The permeation coefficient of compacted loess decreases with the dry density or confining pressure increase,and the change tends to be gentle when they increase to certain content. Dry density and confining pressure have great influence on the anisotropic permeability of compacted loess. The permeability anisotropy of compacted loess decreases with the dry density or confining pressure increase.
引文
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[12]高凌霞,栾茂田,杨庆,等.非饱和重塑黏土渗透性试验研究[J].岩土力学,2008,29(8):2265-2270.(Gao Lingxia,Luan Maotian,Yang Qing,et al.Experimental study of permeability of unsaturated remoulded clays[J].Rock and Soil Mechanics,2008,29(8):2265-2270.(in Chinese))
[2]童朝霞,周少鹏,姚仰平,等.测定各向异性砂土抗剪强度特新型直剪装置及初步应用[J].岩石力学与工程学报,2012,31(2):2579-2584.(Tong Zhaoxia,Zhou Shaopeng,Yao Yangping,et al.An improved direct shear apparatus for shear strength of anisotropic sands and its primary application[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(12):2579-2584.(in Chinese))
[3]梁燕,邢鲜丽,李同录,等.晚更新世黄土渗透性的各向异性及其机制研究[J].岩土力学,2012,33(5):1313-1318.(Liang Yan,Xing Xianli,Li Tonglu,et al.Study of the anisotropic permeability and mechanism of Q3 loess[J].Rock and Soil Mechanics,2012,33(5):1313-1318.(in Chinese))
[4]王铁行,罗扬,王娟娟.黄土节理抗剪强度特性试验研究[J].地下空间与工程学报,2013,9(3):497-501.(Wand Tiehang,Luo Yang,Wang Juanjuan.Experimental research on shear strength of the loess joints[J].Chinese Journal of Underground Space and Engineering,2013,9(3):497-501.(in Chinese))
[5]王栋,金霞.考虑强度各向异性的边坡稳定有限元分析[J].岩土力学,2008,29(3):667-672.(Wang Dong,Jin Xia.Slope stability analysis by finite elements considering strength anisotropy[J].Rock and Soil Mechanics,2008,29(3):667-672.(in Chinese))
[6]王铁行,卢靖,张建锋.考虑干密度影响的人工压实非饱和黄土渗透系数的试验研究[J].岩石力学与工程学报,2006,25(11):2364-2368.(Wang Tiehang,Lu Jing,Zhang Jianfeng.Experimental study on permeability coefficient of artificially compacted unsaturated loess considering influence of density[J].Chinese Journal of Rock Mechanics an Engineering,2006,25(11):2364-2368.(in Chinese))
[7]宋晓宇,黄茂松,王卫东.考虑土体强度各向异性基坑抗隆起上限分析[J].地下空间与工程学报,2009,5(1):28-34.(Song Xiaoyu,Huang Maosong,Wang Weidong.Basal stability of excavations in anisotropic clays by upper bound analysis[J].Chinese Journal of Underground Space and Engineering,2009,5(1):28-34.(in Chinese))
[8]吴超,艾智勇.渗透各向异性饱和层状地基中的抽水问题[J].地下空间与工程学报,2010,6(1):174-178.(Wu Chao,Ai Zhiyong.Water plunping from saturated multi-layered soils with anisotropic permeability[J].Chinese Journal of Underground Space and Engineering,2010,6(1):174-178.(in Chinese))
[9]艾智勇,曾文泽.渗透各向异性多层地基的轴对称Biot固结[J].岩土工程学报,2011,33(2):242-246.(Ai Zhiyong,Zeng Wenze.Axisymmetric Biot’s consolidation of multi-layered soils with anisotropic permeability[J].Chinese Journal of Geotechnical Engineering,2011,33(2):242-246.(in Chinese))
[10]王全胜,艾智勇.二维渗透各向异性多层地基Biot固结分析[J].地下空间与工程学报,2010,6(1):48-52.(Wang Quansheng,Ai Zhiyong.Twodimensional Biot consolidation of multi-layered soils with anisotropic permeability[J].Chinese Journal of Underground Space and Engineering,2010,6(1):48-52.(in Chinese))
[11]赵彦旭,张虎元,吕擎峰,等.压实黄土非饱和渗透系数试验研究[J].岩土力学,2010,31(6):1809-1812.(Zhao Yanxu,Zhang Huyuan,LüQingfeng,et al.Experimental study of unsaturated permeability coefficient of compacted loess[J].Rock and Soil Mechanics,2010,31(6):1809-1812.(in Chinese))
[12]高凌霞,栾茂田,杨庆,等.非饱和重塑黏土渗透性试验研究[J].岩土力学,2008,29(8):2265-2270.(Gao Lingxia,Luan Maotian,Yang Qing,et al.Experimental study of permeability of unsaturated remoulded clays[J].Rock and Soil Mechanics,2008,29(8):2265-2270.(in Chinese))