| Popis: |
By using vertical and horizontal samples of undisturbed fibrous peat containing the amount of organic matters of 20%-80%, the volume change behavior during compression-swelling-recompression was investigated under an isotropic stress condition, and the change of pore diameter distribution due to compression was measured with a porosimeter apparatus. Moreover, in order to investigate the volume change behavior during drained shear on the isotropically normally consolidated specimens, the two series of triaxial compression tests, in which axial stress was increased while lateral stress or effective mean stress was maintained constant, were performed.Test results indicate that the large majority of openings of undisturbed samples of peat by has the pore diameters in the ranges of 100 μm-0.1 μm, and by compressing, the number of openings with the pore diameter of 0.1 μm-0.1 μm increases. The volume change of void space due to isotropic effective stress increment can be quantitatively estimated with the two inclinations C^-c and C^-s of compression-swelling line plotted on ln e vs. ln p' plane. Also, it was found that the amount of dilatancy of normally consolidated peat showed the linear relation against shear stress ratio and the rate of that to total volume change of peat element was roughly 0.3 over a wide range of shear stress ratio. Furthermore, it was verified that the total volume change could be represented by the sum of change due to the increment of effective mean stress and that due to the increment of deviatoric stress. |
