Automated inverse analysis of a deep excavation in Ankara clay using finite element analysis

Engin T. A., ÇOKÇA E.

ARABIAN JOURNAL OF GEOSCIENCES, vol.14, no.19, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 19
  • Publication Date: 2021
  • Doi Number: 10.1007/s12517-021-08310-w
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aquatic Science & Fisheries Abstracts (ASFA), Geobase, INSPEC
  • Keywords: Deep excavation, Ankara clay, Inverse analysis, Python code, Constitutive soil model, Case study
  • Middle East Technical University Affiliated: Yes


The objective of this study is to find out the constant that shows a linear relationship between the deformation modulus parameter of Ankara clay and SPT N-60 values by using Plaxis 2D software. During analyses, three constitutive models are used, those are Mohr-Coulomb (MC), hardening soil model (HS), and hardening soil model with small strain stiffness (HSsmall). For that purpose, reverse analysis of a 25.0-m deep excavation was done by comparing results with displacements taken from inclinometer measurements. Instead of using an idealized soil profile, soil layers are divided into 1.5-m thicknesses according to SPT N measurement depths; and for each interval, soil parameter correlation is performed. To minimize time loss, analyses were performed by writing a Python code. Finally, results were evaluated by comparing soil models with each other, and it is found out that displacement curves of the MC model could not converge to the actual displacements. Analyses results of the HSsmall model are the closest displacements to the measured values on the site. Also, displacement curves of the hardening models (HS and HSsmall) are almost similar, and the linear correlation constant is found as E-50(ref) similar to 780xN(60) kPa for this excavation of the case study in Ankara clay in HS and HSsmall models.