Liquefied Residual Strength of Undrained Sand upon A Parametric Approach to Hypo-elastic Model

A parametric study approach evaluating drained/undrained behavior of sand has been developed as a simple/quick hypo-elastic model capable of being used in engineering applications. The volumetric interaction of sand grains behavior against pore water pressure induces the tendency of soil mass volume change to contract/dilate due to variation of effective mean stress on solid grain, pore water pressure by compressibility and shear induced dilation/compression which lead to an ideal condition for constant total volume of undrained test. However, any individual volume changes of named components may result in a partial reduction of the effective mean stress to an extent that can be disclosed as a local decrease in stress deviator. In the extreme case, the effective stress components may become so small (or even zero) resulting in complete loss of strength and cause the soil to flow in a manner resembling a liquid known as liquefaction of sand. However, in real case, any possibility of water dissipation or volumetric change tendency of components can change the state/condition to activate some shear strength by increasing the effective mean stress. The proposed parametric study approach is able to present such volumetric variation condition leading to partial or complete liquefaction condition. This model has predicted and verified several compression triaxial test results of sands. The verification of model is presented by comparing the obtained results with the experimental result of Nevada sand, in both drained and undrained conditions. The proposed model can be successfully used for other soils behavior by using the proposed parametric study method including the required parameters to achieve acceptable results.