G-PFEM Modelling of Cone Penetration in Layered Soils
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Cone penetration test with pore pressure measurements (CPTu test) is the dominant tool for most soft soil characterization problems. When testing a certain soil layer, the response of the cone may be affected by nearby layers characterised by different properties. Quantifying this interface effect is of interest in many applications, including liquefaction risk assessment. A numerical investigation is advantageous in this kind of study as physical experiments are slow to perform, particularly if consolidation is involved. A code based on the Particle Finite Element Method [1], adapted for the analysis of fully hydromechanically-coupled geotechnical problems (G-PFEM; [2]), is here employed to analyse CPTu tests in layered soils. The code is able to satisfactorily tackle problems involving large displacements and large strains as well as non-smooth soil/rigid body contacts. Non-local regularization and mesh smoothing techniques are applied to deal effectively with changing properties not only at the soil-cone interface but also at the interface between soil layers. The soils are described using the CASM constitutive model [3]. While previous numerical studies of this problem have addressed layering induced changes on tip resistance, this study also considers the response in terms of pore water pressure. Effects of changes in both hydraulic conductivity and cone roughness are separately explored.
