This paper is focused on sensitivity analysis of the behavior of subsoil foundation systems by considering the variant properties of a fiber concrete slab that result in different relative stiffness of the whole cooperating system. The character of the slab and its properties are very important for the character of external load transfer. However, the character of the subsoil also cannot be neglected because it determines the stress–strain behavior of the entire system and, consequently, the bearing capacity of the structure. The sensitivity analysis was carried out based on experimental results, which included both the stress values in the soil below the foundation structure and settlements of the structure that are characterized by different quantities of fibers in it. Flat GEOKON dynamometers were used for the stress measurements below the observed slab, the strains inside the slab were registered by tensometers, and the settlements were monitored geodetically. This paper is focused on the comparison of soil stresses below the slab for different quantities of fibers in the structure. Results obtained from the experimental stand can contribute to more objective knowledge of the soil-slab interaction, the evaluation of real carrying capacity of the slab, the calibration of corresponding numerical models, the optimization of quantity of fibers in the slab and finally, contribute to higher safety and more economical designs of slabs.

This paper presents an approach that enables the specific characteristics of a primary tunnel lining implemented using numerical modelling to be taken into account during its design. According to the fundamental principles of the New Austrian Tunnelling Method, the primary lining undergoes time-dependent deformation, which is determined by its design. The main design element is shotcrete, which, shortly after its application, interacts with the surrounding rock mass and steel arch frame. The primary lining ensures the equilibrium stress–strain state of “rock mass–tunnel lining” during excavation. The structural interaction varies depending on the hardening of the shotcrete, the rheological properties of the rock mass, and other factors. The proposed approach uses the Homogenisation software application, which was developed by the Faculty of Civil Engineering at the Department of Geotechnics and Underground Engineering of the VSB—Technical University of Ostrava. This software allows the heterogeneous structure of the lining to be considered by replacing it with a homogenous structure. The parameters of the homogeneous primary lining, which take into account the steel reinforcement elements and the time-dependent property of the shotcrete, are included in numerical models.

The paper deals with the back analysis method in geotechnical engineering, that goal is evaluation the more objective and reliable parameters of the rock mass on the basis of in-situ measurements. Stress, deformational, strength and rheological parameters of the rock mass are usually determined by some inaccuracies and errors arising from the complexity and variability of the rock mass. This higher or lower degree of imprecision is reflected in the reliability of the mathematical modelling results. The paper presents the utilization of direct optimization back analysis method, based on the theory of analytical functions of complex variable and Kolosov-Muschelischvili relations, to the evaluation of initial stress state inside the rock massif.

Dependency of Elastic Modulus and Stress Redistribution Coefficients on a Layout of Steel Reinforcement in Steel-Concrete Cross Section The paper presents the outputs of a computational parametric study investigating the influence of both reinforcement ratio and scheme of a cross-section reinforcement on a design value of the elastic module for the homogenized cross-section and the values of the stress redistribution coefficients. The design value of the elastic module represents the steel-concrete cross section in the calculations. The stress redistribution coefficients converts the state stress in the homogenized cross-section for the state stress in steel and concrete individually. The design value of the homogenized cross-section elastic module and the stress redistribution coefficients are determined from the theory of the cooperating rings and computed by program HOMO. The result of a study is a set of the stress redistribution coefficients and a dependency of stress redistribution coefficients on the reinforcement ratio of a steel-concrete section.