Consequences of geometrical imperfections for deep dry mixing columns in a deep excavation pit

Abstract

Few studies have analysed the deep excavation retaining wall system response when passive-sided panels of load-bearing deep dry mixing columns are installed with geometrical imperfections. This study applies parametric 3D modelling to generate DDM panel geometries with random geometric imperfections for individual columns drawn from a probability distribution. Simulations are performed with FEA to investigate the retaining wall response from imperfect panels. Comparisons are made to both idealized rectangular panels and panels consisting of octagonal columns without imperfections. Four column imperfections are considered - XY offset, azimuth, length and inclination. Results indicate that geometric panel imperfections contribute to overall greater horizontal displacement, shear force, bending moment and strut forces in the retaining wall system. This study considered 101 simulations with imperfect panels. Although the number of simulations performed in this study is modest, initial results indicate that the moving average of the response is converging as the simulation count is increased.