Undrained Creep Rupture of Normally Consolidated Clay Due to Bifurcation Mode Switching During Pore Water Migration
In the present study, we newly interpret the undrained creep rupture of normally consolidated soil as a result of the change in the initial higher bifurcation mode to lower one during pore water migration within the clay; i.e., “mode switching”. The computation is performed not as a single soil element as in the classical soil mechanics, but as a soil-water coupled initial-boundary value problem of a soil specimen, in which only the “inviscid” original Cam-clay model with the subloading surface concept and the Darcy’s law are used. As a result, just after the constant applied load, the axial strain is progressing at a very slow rate, however, the strain rate increases immediately when the strain reaches 5.7%. During the time, it is observed that the excess pore pressure tends to be homogeneous and then rises again due to the occurrence of softening in some element.
KeywordsAxial Strain Mode Switching Excess Pore Pressure Soil Specimen Triaxial Compression Test
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