# COMPUTATIONAL STUDY USING DISCRETE ELEMENT METHOD FOR STRESS-STRAIN RESPONSE OF GEOMATERIALS

## Palavras-chave:

Computational Geomechanics, Uniaxial Compression Simulation, Stress-strain response, Geomaterials, Discrete Elements## Resumo

Relevant geomaterials, like soils, concretes or rocks, exhibit similar constitutive response

when considering their yield strength dependencies or dilatancy processes. The continuous description

of these geomaterials encounters limitations when large-scale slip and opening of a large amount of

fractures. Discrete-based methods represent the material as an assemblage of independent elements

interacting with one another and can be reproduce the discrete nature of the discontinuities, which are

represented as the boundary of each element. In this case, for each particle, the interaction law is used

in conjunction with the momentum balance principle so as to specify a set of governing equations to

describe its interactions and motion. By solving these equations, we obtain the final state of rest of

these particles. The constitutive stress-strain response is obtained in an uniaxial compression

experiment were a sample of geomaterial is slowly compressed by a piston until failure occurs. The

peak stress at which failure of the sample occurs is known as Unconfined Compressive Strength

(UCS). This work studies these responses in geomaterials samples using Discrete Element Method

(DEM). In our numeric simulation, a set of particles is placed between two piston walls which are

compressed at constant speed. Then, we monitor the position and forces for construct a curve by each

sample. Interactions incorporate translational and rotational degrees of freedom to rotate relative to

each other when in frictional contact. Analytical relationship between the microphysical parameters

and the macroscopic properties can be obtained by conducting a series of computational simulations to

tune the microphysical parameters until desired macroscopic properties. To simulate elastic-brittle

failure of material, a Mohr-Coulomb criterion is employed. These data are used to measure some

elastic properties of the particle model such as Young’s modulus, wall forces, broken bond and the

UCS himself. Results shows that possible obtain significant values for different geomaterials such as

some specific concretes and rocks.