Rock Mechanics
Vahab Sarfarazi; Hadi Haeri; Jinwei Fu; Shadman Mohammadi Bolbanabad; Alireza Shaker
Abstract
In this research, samples of bi-material notch discs were created and examined in the laboratory to investigate their mechanisms of indirect tensile failure. Brazilian tensile strength tests were conducted to determine the mechanical properties of these samples under a loading rate of 0.016 mm/s. The ...
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In this research, samples of bi-material notch discs were created and examined in the laboratory to investigate their mechanisms of indirect tensile failure. Brazilian tensile strength tests were conducted to determine the mechanical properties of these samples under a loading rate of 0.016 mm/s. The discs were designed with a central notch and were made from two materials: concrete and gypsum. Gypsum (Material 1) was placed at the center (core), while concrete (Material 2) was used to form a peripheral strip (ring) around this core. The core diameter and ring thickness were varied, resulting in a total of 21 specimens that were prepared and subjected to axial loading during testing. To support the experimental results, the Particle Flow Code (PFC) was utilized to simulate the tests. It was observed that both the notch dimensions and the choice of materials significantly influenced the mechanical behavior and fracture characteristics of anisotropic rocks. Furthermore, based on the results obtained from the laboratory samples and the modeling of these samples using PFC software, strong agreement was achieved regarding crack growth behavior. In addition, a comprehensive study was conducted on the samples through numerical modeling, which included the distribution of bond forces and Rosette diagrams, as well as crack growth patterns.
F. Rastegar; H. R. Nejati; A. Ghazvinian; M. R. Hadei; A. Nazerigivi
Abstract
The tensile strength of rocks plays a noteworthy role in their failure mechanism, and its determination can be beneficial in optimizing the design of the rock structures. Schistose rocks due to their inherent anisotropy in different foliation directions show a diverse strength at each direction. The ...
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The tensile strength of rocks plays a noteworthy role in their failure mechanism, and its determination can be beneficial in optimizing the design of the rock structures. Schistose rocks due to their inherent anisotropy in different foliation directions show a diverse strength at each direction. The purpose of this work was to compare and assess the tensile strength of phyllite, which was obtained in direct and indirect tensile tests in different foliation directions. To this end, several phyllite specimens with different foliation angles (0º, 30º, 45º, 60º, and 90º) related to the loading axis (β) were prepared. Finally, the direct tensile test, diametrical and axial point load tests, Brazilian test, and Schmidt hammer test were conducted on 188 samples. The results of the experimental tests revealed that the maximum and minimum tensile strengths in direct tensile testing tension were directly related to the angles of 0º and 90º. Also it was observed that the Brazilian tensile strength overestimated the tensile strength. Furthermore, an exponential correlation was introduced between the direct tensile strength and the Brazilian tensile strength.
