Author(s)

P. P. Prochazka & J. Trckova

Abstract

Numerical methods seem to be the cheapest tool for assessing underground structures. However, there exists one obstacle in applications of any numerical method which is a lack of information concerning the input data, particularly the knowledge of material properties. If the theory of damage should be involved in the formulation of the problem to be solved, special treatment is required. The methods, which are extensively used, start with realization of the trial body by a continuum. We can name \“Cohesive zone method”, which deals with Barenblatt's theory, for example. In our problem such methods are difficult to apply and exhibit unreal behavior, according to a couple of test examples. This is why test experiments have been carried out to gain further information towards a reasonable approach for solving the problem. The free hexagon method seems to be very promising. The method will be described and basic formulas will be derived, and then applications to assessment of structural strength will be presented. Keywords: distinct element methods, the free hexagon method, laboratory experiments, structural strength. 1 Introduction The free hexagon method belongs to a great family of discrete element methods, Cundall, [1], Moreau [5]. It enables designers and researchers to describe the material behavior of structures from the point of view of damage mechanics, localization of stresses and fracture mechanics. Why hexagonal shape of the elements? The answer is: this shape is "almost" circular (the shape of grains, stones, fibers, etc.) and in the same time it is possible to cover the domain describing the structure (or its part) with the least geometrical error.

Keywords

distinct element methods, the free hexagon method, laboratory experiments, structural strength