文章摘要
姚涛,邵龙潭.三轴数字图像测量技术在黄土力学特性研究中应用[J].,2009,(1):92-97
三轴数字图像测量技术在黄土力学特性研究中应用
Application of triaxial digital image measurement to research on loess mechanical behaviour
  
DOI：10.7511/dllgxb200901018
中文关键词: 数字图像测量  黄土  结构强度  湿陷系数  应力-应变关系
英文关键词: digital image measurement  loess  structure strength  collapsibility coefficient  stress-strain relation
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作者单位
姚涛,邵龙潭  
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中文摘要:
      常规三轴试验仪难以准确测定出土体径向变形和体积变形，因此将其应用于黄土等典型非饱和土研究时必须改进其量测系统．将数字图像测量方法应用于黄土变形研究中，通过非接触式测量不但可以避开端部约束对试样的影响，同时可以测量土样各个断面的径向变形；通过测定不同固结压力下试样的体积应变，在 ε v-lg p 曲线上与曲率半径最小的点相对应的围压值确定为土体的结构强度；通过计算试样剪切过程中实时的截面面积进而准确地反映出土体的应力-应变关系；通过对图像分析可以捕捉到土样在低含水量、低围压下出现的剪切带．将数字图像测量方法应用于黄土湿陷系数的测量，可以将不同应力条件下的湿陷轴向应变作为相对湿陷系数，将湿陷体积应变作为广义湿陷系数，结合结构强度与湿陷体积应变对黄土湿陷变形特性进行了很好的诠释．
英文摘要:
      Loess belongs to unsaturated soil, and it is difficult to exactly measure its radial and volume deformation. This problem can be well solved by the digital image measurement technique using non-contact measurement to avoid the end restriction effect on the specimen, and can also obtain the radial deformation of each section. Measuring the volume strain under different consolidation pressure, the structure strength of the soil mass can be regarded as the confining pressure that corresponds to the minimal curvature radius point on the ε v-lg p curve. With digital image measurement technique in the shearing stage, the section area during the specimen deformation process can be taken into account to calculate the stress, hence the stress-strain relationship under different confining pressure can be more accurate, and at the same time, the shear band in the condition of low water content and low confining pressure can also be observed. Using digital image measurement technique to measure loess collapsibility coefficient, not only can the relative collapsibility coefficient under different stress conditions be attained, but also the collapse deformation can be interpreted by the collapsibility volume strain and confining pressure relationship curve along with structure strength, where collapsibility volume strain is regarded as general collapsibility coefficient.
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