Tomohide Takeyama

Stress–Strain Relationship for the Singular Point on the Yield Surface of the Elasto-Plastic Constitutive Model and Quantification of Metastability

In this chapter, the stress–strain relationship on the singular point of the yield surface of the original Cam clay model and the Sekiguchi-Ohta’s model is derived in order to compute the volume change correctly. Metastable space, the range of increment of strain in which effective stress does not get away from the singular point of yield surface, was theoretically derived. In metastable space, the increment of volumetric strain is larger than the increment of deviatoric strain.

Spatial Discretization of a Water Head in Soil–Water Coupled Finite Element Method Analysis Using the Hybrid-Type Penalty Method

In the present soil–water coupled finite element method (FEM) analysis, a program known as deformation analysis considering stress anisotropy and reorientation (DACSAR; Iizuka and Ohta, Soil Found 27(3): 71–87, 1987), the spatial discretization procedure for representing the water head at the center of each finite element was adopted. However, it is known that the outflow of pore water from the element boundary happens to be incorrectly calculated depending on the mesh arrangement and the inclination of the boundary. To address this problem, this chapter proposes a more rigorous spatial discretization procedure for pore water flow. Namely, the hybrid-type penalty method (HPM) is introduced to spatially discretize the pore water flow in soil–water coupled finite element formulation, and the DACSAR program is modified using the proposed technique.