SECTION BUILDING STRUCTURES & STRUCTURAL MECHANICS VOLUME: 18 | NUMBER: 2 | 2018 | DECEMBER © 2018 TRANSACTIONS OF VSB - TECHNICAL UNIVERSITY OF OSTRAVA CIVIL ENGINEERING SERIES 60 Numerical Analysis of Subsoil-Reinforced Concrete Slab Interaction Tuan Duc LE 1 , Qui Thanh NGUYEN 1 and Radim CAJKA 2 1 Department of Structural Mechanics, Faculty of Civil Engineering, VSB - Technical University of Ostrava, Ludvika Podeste 1875/17, 708 33 Ostrava - Poruba, Czech Republic 2 Department of Building Structures, Faculty of Civil Engineering, VSB - Technical University of Ostrava, Ludvika Podeste 1875/17, 708 33 Ostrava - Poruba, Czech Republic duc.tuan.le.st@vsb.cz, qui.nguyen.thanh.st@vsb.cz, radim.cajka@vsb.cz DOI: 10.31490/tces-2018-0018 Abstract. This article presents the numerical modeling of interaction between a reinforced concrete slab and subsoil using ABAQUS. Subsoil was simulated as both homogeneous half-space and inhomogeneous half-space. Reinforcement bars in the concrete slab were accurately modelled allowing capturing a precise deformation profile of the slab in interaction with subsoil. Input data for numerical analysis were adopted from a published work. Results of the study were verified on the basis of comparison with those of the previous study. Keywords Deformation, finite element method, interaction models, numerical models, reinforced concrete slab, subsoil- structure interaction. 1. Introduction Researches on subsoil-structure interaction have been intensively done over recent years. Those studies have covered many aspects of the interaction [1], [2], [3], [4], [5], [6] and [7]. For instance, R. Cajka 2013 presented a method of determination of friction parameters for soil- structure interaction [5]. Stress strain analysis of elastic half-space using Gauss numerical integration and Jacobean of transformation was conducted by R. Cajka in 2013 [6] and results were further analyzed by R. Cajka and J. Labudkova in 2015 [7]. In addition, experimental measurements of stress and subsidence in subsoil were also carried out by many researchers such as G.X. Mei et al. 2005 [8], Cajka et al. 2014 [9] and [10]. M. Mohyla et al. 2017 [11] analyzed stress under foundation slab with a physical surface interface between foundation slab and the subsoil by experimental measurement. Measurements from site tests and experiments allow having a better understanding about behaviors of both subsoil and structure as well as their interaction. Unfortunately, in-situ tests and site experiments are usually expensive and time consuming. As a result, numerical analysis of subsoil-structure interaction has become a current trend. Researchers and experts are improving and developing the analysis of subsoil- structure interaction based on finite element methods (FEM) or based on the combination of both experimental measurements and FEM. For example, R. Cajka 2014 [12] made a comparison of calculated values of settlement and stress state of concrete slab on subsoil and those values got from experiments. In 2014, R. Cajka and J. Labudkova [13] described how calculated deformations depend on parameters of soil environment modeled by 3D finite elements. Deformation and contact stress of the slab and subsidence of the subsoil were calculated by using two FEM programs, Scia Engineer [14] and Mkpinter (a non-commercial software created by Cajka R., co-author of this paper), in [15]. Numerical interaction model of reinforced concrete (RC) slab and subsoil was also modelled in ANSYS [16] with application of inhomogeneous half-space to get better subsoil behavior [17]. This model was also applied to simulate the interaction between subsoil and steel-fibre reinforced concrete slab in [18]. This research aimed at the analysis of the interaction between subsoil and RC slab under the scheme of FEM. The study can be considered as a continuing development of the work of [17] on which ABAQUS [19] is used instead of ANSYS and reinforcement bars in the concrete slab are modelled with more realistic 3D body. In addition, this work took into account of the influence of friction between the subsoil and the slab which was neglected in [17]. Furthermore, the non-linear material