Plane Strain Simplified Analysis of Consolidation of a Foundation Penetrated by Concrete-Cored Gravel Columns

The consolidation solutions of the foundation penetrated by the concrete-cored gravel (CCG) columns have been proposed based on a single-column model under the axisymmetric condition. A CCG column consists of a precast concrete pile inserted at the center of sand or gravel materials. Numerical modeling is commonly adopted for multicolumn field applications. Converting the axisymmetric unit cell into the plane strain model saves computation load and numerical simulation time. This study proposed a plane strain conversion method for the foundation penetrated by CCG columns. The plane strain conversion goes through a geometric transformation, stiffness equivalence, and consolidation equivalence. The consolidation equivalence is conducted by equating the consolidation degree at any depth of the plane strain model to that of the axisymmetric model. The penetration effect of the converted inner wall is used to modify the equal strain assumption of the plane strain model. The validity of the proposed method is examined by comparing it with 3D numerical simulation results and the field data from an embankment case history. The comparison reveals that the proposed plane strain conversion method enables the numerical simulation of the CCG column-reinforced foundation to be handled easily and largely saves the computation resources.