Stress Analysis for Rock Mass Failure with Offset Joints

Abstract

Two-dimensional finite element model was created in this work to investigate the stress distribution within rock-like samples with offset open non-persistent joints under uniaxial loading. The results of this study have explained the fracture mechanisms observed in tests on rock-like material with open non-persistent offset joints (Mughieda and Alzo 'ubi, Geotech Geol Eng J 22:545-562, 2004). Finite element code SAP2000 was used to study the stresses distribution within the specimens. Fournoded isoperimetric plain strain element with two degrees of freedom per node, and the three-noded constant strain triangular element with two degree of freedom per node were used in the present study. The results of the present study showed that the tensile stress in the bridge area caused coalescence for specimens with overlapped preexisting cracks (joints) while the coalescence of the secondary cracks, due to shear stress, caused the failure of specimens with non-overlapping cracks.

Numerical study on failure behavior of brittle rock specimen containing pre-existing combined flaws under different confining pressure

“…Mughieda and Omar [16] investigated the stress distribution of rock containing two fissures by using the finite element code with the name of SAP2000. The simulated results showed that tensile stress was mainly responsible for wing crack initiation while the shear stress was responsible for the a r c h i v e s o f c i v i l a n d m e c h a n i c a l e n g i n e e r i n g x x x ( 2 0 1 5 ) x x x -x x x a r t i c l e i n f o secondary crack initiation.…”

An Experimental and Numerical Study on Cracking Behavior of Brittle Sandstone Containing Two Non-coplanar Fissures Under Uniaxial Compression

“…In order to understand the fracture mechanism of rock engineering, many experimental and numerical investigations have been carried out on rocks containing various fissures (Lee and Jeon 2011;Li et al 2005;Mughieda and Omar 2008;Vásárhelyi and Bobet 2000;Wong and Einstein 2009;Yang et al 2012), which show that pre-existing fissures in natural rock masses have a great influence on their strength, deformation, and fracture coalescence behavior (Hall et al 2006;Lee and Jeon 2011;Li et al 2005;. Hall et al (2006) carried out an experimental study on natural and dry specimens of Neapolitan fine-grained tuff, and analyzed the crack coalescence processes of specimens containing one and two pre-existing fissures using acoustic emission (AE) and photographic monitoring, which were helpful to predict sudden and unexpected collapses of underground rock engineering.…”

“…With the development of numerical methods, many simulation softwares have been adopted to analyze the crack coalescence processes of real rock material, including SAP2000 (Mughieda and Omar 2008), FROCK (Vásárhelyi and Bobet 2000), PFC 2D (Lee and Jeon 2011;, RFPA 2D (Tang 1997;Tang et al 1997), the boundary element method (BEM) (Chen et al 1998;Shen and Stephansson 1993;Shen 1995), cellular automata (CA) (Feng et al 2006;Pan et al 2009), and X-FEM (Colombo and Massin 2011;Grégoire et al 2007;Rozycki et al 2008). Mughieda and Omar (2008) investigated the stress distribution of rock containing two fissures using the finite element code SAP2000.…”

“…Mughieda and Omar (2008) investigated the stress distribution of rock containing two fissures using the finite element code SAP2000. The simulated results showed that tensile stress was mainly responsible for wing crack initiation, while shear stress was responsible for secondary crack initiation.…”

Numerical investigations on slope stability using an elasto-brittle model considering fissure water pressure

“…Tang et al (2001) developed some numerical methods to simulate the initiation and coalescence of flaws in rock-like materials, including the finite element method (FEM), boundary element method (BEM), and displacement discontinuity method (DDM), and Tang and Kou (1998) also proposed a new numerical code named Rock Failure Process Analysis (RFPA2D) to simulate the propagation and coalescence of cracks in a rock bridge area. In addition, the discrete element method (DEM) is also used to simulate the mechanical behavior of rock-like materials (Lee and Jeon 2011;Yang et al 2014;Manouchehrian et al 2014;Mughieda and Omar 2008). Fang and Harrison (2002a, b) adopted a degradation model to simulate the brittle failure in heterogeneous rocks.…”