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AbstractThe electrokinetic treatments on high natural moisture content, large compressibility, and low strength dredged marine soil are regarded as an innovative method, but it has not been widely applied due to the difference between theory predictions and realities. To minimize the difference which is resulted from the electric permeability coefficient variations due to pore water drainage and the degree of saturation drops during the electrokinetic treatment of soils, several one-dimensional indoor experiments were conducted with single kaolin clay and natural soft clay. The test results indicate that the electric permeability values conform to the predicted value of Helmholtz–Smoluchowski (H-S) theory under saturated conditions. The permeability for unsaturated soils can be described with relative electric permeability, that is, ke,rel=a(Sr)b. The ranges of fitting parameters are 0.8–1.2 for a and 3–9 for b. The fitting parameters are dependent on the soil type, electric potential gradient, and pore size distribution and so on. The smaller the soil pore size is the more sensitive the permeability coefficient is to the degree of saturation. 相似文献
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This paper deals with numerical modelling of anisotropic damage induced by desaturation and resaturation processes in a brittle rock. This study is conducted in the framework of geological barrier safety analysis for deep disposal of nuclear waste. A non-linear poroelastic model coupled with anisotropic damage is proposed for constitutive modelling of unsaturated rock. A fully coupled FEM method is used for modelling of hydromechanical coupling problems. Instantaneous phase change without dissipation between water liquid phase and vapour is included. Parametric studies are performed to investigate influences of main factors involved in such processes. Rock damage induced by excavation, desaturation and resaturation is evaluated. Finally, we analyse the importance of taking into account the correlation between induced damage and rock permeability. 相似文献
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A numerical investigation of the desaturation process at the argillaceous Tournemire site has been carried out. This desaturation
is initialized by the contact of the saturated rock with the ambient air in excavated openings. The used hydraulical model
is based on the Richards’ approximation for unsaturated one phase flow coupled with the deformation of a porous medium with
anisotropic linearly elastic behavior. In relation to the extent of the desaturated zone around an excavated opening, the
intrinsic permeability and the relative permeability have been identified to be the most important model parameters. The mechanical
deformation process itself, the seasonal influences and the tunnel lining are less important for the formation of the desaturated
zone. The comparison with measured saturation values bares some difficulties but indicates the principle capacity of the applied
finite element codes to simulate the desaturation process. The consideration of seasonal changes in humidity in the ambient
air results in a constantly recurring desaturation–resaturation cycle in the near field of the openings. This seasonally influenced
zone amount 1–2 m and is nearly independent from time and from a variation of model parameters within a reasonable range.
The possibility of material weakening in this zone is of special interest, since claystone is a potential host rock for the
disposal of radioactive waste. 相似文献
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从电阻率的角度研究岩石裂隙介质的各向异性特征是一种方便而有效的方法,但多限于空间单个点上的测量数据分析.通过在砂岩岩样上的饱水与排水实验以及同步进行的高密度电阻率成像监测,探讨了应用高密度电阻率成像法获得图像研究岩石各向异性特征的可能性,分析了饱水与排水过程中岩石电阻率在不同方向上的响应特性.结果表明,电阻率成像法在分析岩石裂隙介质的各向异性方面具有多方向成像和动态监测的优点,可以通过对不同方向上获得的电阻率图像的分析,提取出岩石沉积结构的空间分布模式,清晰地反映出岩石在饱水和排水过程中电阻率变化空间分布模式的各向异性特征. 相似文献
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