Investigation of numerical modelling approaches for diaphragm walls with support of inverse parameter identification

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4. Investigation of numerical modelling approaches for diaphragm walls with support of inverse parameter identification

Numerical investigations using Finite Element Analyses (FEA) with different modelling approaches for diaphragm walls are conducted considering a 20m deep excavation pit with available horizontal deformation measurement data. The subsoil mainly consists of different sand layers. For realistic soil-behaviour representation, a high-quality constitutive model (Hardening Soil small strain stiffness) is used. The stiffness parameters are determined using inverse parameter identification (particle swarm optimization) by comparison with measured horizontal deformations of the wall. The measurement data show that the diaphragm wall has deflected significantly; therefore, a calibration with complete agreement with the classic linear-elastic wall consideration is not possible.

Based on this, the following approaches of modelling the diaphragm wall are investigated: linear-elastic continuum as well as structural elements, elastoplastic structural elements with a user-defined M-k diagram and an elastoplastic concrete model. To identify the optimal modelling variant for a near-realistic representation of the soil-structure interaction, the bending moment distributions are compared. The results show that the excavation process causes plastic deformations of the wall, leading to higher horizontal deformations in the final state when the elastoplastic material models are considered.

10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)

2. Finite element, finite difference, discrete element, material point and other methods