Omid Mahabadi

Omid Mahabadi
Geomechanica Inc. · Geomechanics

PhD

About

45
Publications
33,737
Reads
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1,749
Citations
Citations since 2017
6 Research Items
1331 Citations
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2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
Introduction
Omid holds a PhD degree in civil engineering from the University of Toronto specializing in computational geomechanics. While working at Geomechanica Inc., he uses his knowledge of rock mechanics and numerical modelling by means of hybrid continuum-discontinuum numerical methods to analyze phenomena involving rock fracturing.
Additional affiliations
November 2012 - present
Geomechanica Inc.
Position
  • Geomechanics Expert
July 2012 - October 2012
University of Toronto
Position
  • Research Associate
September 2008 - May 2009
Queen Mary, University of London
Position
  • Research Assistant
Education
September 2007 - April 2012
University of Toronto
Field of study
  • Civil Engineering
January 2005 - June 2005
Newcastle University
Field of study
  • Hydroinformatics
November 2004 - September 2006

Publications

Publications (45)
Article
Full-text available
This study presents the first step of a research project that aims at using a three-dimensional (3D) hybrid finite-discrete element method (FDEM) to investigate the development of an excavation damaged zone (EDZ) around tunnels in a clay shale formation known as Opalinus Clay. The 3D FDEM was first calibrated against standard laboratory experiments...
Article
Full-text available
This study investigates the influence of microscale heterogeneity and microcracks on the failure behavior and mechanical response of a crystalline rock. The thin section analysis for obtaining the microcrack density is presented. Using micro X-ray computed tomography (μCT) scanning of failed laboratory specimens, the influence of heterogeneity and,...
Article
Full-text available
The purpose of this paper is to present Y-Geo, a new numerical code for geomechanical applications based on the combined finite-discrete element method (FDEM). FDEM is an innovative numerical technique that combines the advantages of continuum-based modeling approaches and discrete element methods to overcome the inability of these methods to captu...
Article
Full-text available
The scope of this study is to numerically simulate the behaviour of Brazilian disc specimens as observed in laboratory during dynamic, high-strain rate, indirect tensile tests using an innovative combined finite-discrete element method (FEM/DEM) research code. Laboratory experiments using a split Hopkinson pressure bar (SHPB) apparatus were conduct...
Conference Paper
Full-text available
Coupled thermo-hydro-mechanical (THM) processes play a key role in a variety of geomechanical applications, including, enhanced oil recovery from unconventional reservoirs, deep geological disposal of heat-emitting nuclear waste, and enhanced geothermal systems (EGSs). The research work presented herein introduces a novel fully-coupled, THM formula...
Article
Full-text available
Rock bolt is a support system extensively utilized in Civil and Mining Engineering applications, especially for underground excavations projects. The main function of a rock bolt is to stabilize the rock mass around the opening of an excavation by fastening to further stable formations. Previous technical work developed pull-out testing in order to...
Preprint
Full-text available
Rock bolt is a support system extensively utilized in Civil and Mining Engineering applications, especially for underground excavations projects. The main function of a rock bolt is to stabilize the rock mass around the opening of an excavation by fastening to further stable formations. Previous technical work developed pull-out testing in order to...
Article
This paper presents a novel implementation of a hydro-mechanically coupled, finite-discrete element method (FDEM) optimized to exploit the computing parallelism of graphics processing units (GPUs). A co-processing approach is adopted with the control loop of FDEM executed serially on the CPU and compute-intensive tasks off-loaded to the GPU. A benc...
Article
This paper presents a new, fully-coupled, hydro-mechanical (HM) formulation for a finite-discrete element method computer code. In the newly-developed, hydraulic solver, fluid flow is assumed to occur through the same triangular mesh used for the mechanical calculations. The flow of a viscous, compressible fluid is explicitly solved based on a cubi...
Conference Paper
Full-text available
Standard laboratory testing of Georgian Bay shale and limestone was performed for an ongoing tunnel project in the Greater Toronto Area (GTA). The laboratory results were used as calibration targets to determine input parameters for numerical simulations using the Irazu simulation package based on the hybrid finite-discrete element method (FDEM). U...
Article
Full-text available
The excavation damaged zone (EDZ) around the backfilled tunnels of a geological repository represents a possible release path for radionuclides, corrosion and degradation gases that needs to be adequately addressed by safety assessment (SA) modelling tools. The hydrome-chanical phenomena associated with the creation and temporal evolution of the ED...
Conference Paper
Full-text available
This paper presents the development, verification and application of a new, fully-coupled, hydro-mechanical (HM) formulation for a finite-discrete element method (FDEM) software package called Irazu. FDEM is a general-purpose numerical approach which combines continuum mechanics principles with discrete element algorithms to simulate the mechanical...
Article
Full-text available
The study of acoustic emissions (AEs) is of paramount importance to understand rock deformation processes. AE recorded during laboratory experiments mimics, in a controlled geometry and environment, natural and induced seismicity. However, these experiments are destructive, time consuming and require a significant amount of resources. Lately, signi...
Conference Paper
Full-text available
This study aims at strengthening the understanding of the mechanical sealing process of the excavation damaged zone (EDZ) in Opalinus Clay, an indurated claystone currently being assessed as the host rock for a deep geological repository in Switzerland. To achieve this goal, hybrid finite-discrete element method (FDEM) simulations are applied to th...
Article
Full-text available
The analysis and prediction of the rock mass disturbance around underground excavations are critical components of the performance and safety assessment of deep geological repositories for nuclear waste. In the short term, an excavation damaged zone (EDZ) tends to develop due to the redistribution of stresses around the underground openings. The ED...
Conference Paper
Full-text available
Fluid-pressure-driven (or hydraulic) fracturing of rocks is used in several applications including stimulation of unconventional reservoirs, permeability enhancement of geothermal systems, and rock mass pre-conditioning in deep mining. In recent years, there has been a fast growing interest in the development and use of dvanced numerical methods to...
Research
Full-text available
The scope of this study is to simulate the behaviour of a heterogeneous Barre granite rock sample and a bedded rock sample under standard laboratory Brazilian Disc test using an innovative combined finite-discrete element method (FEM/DEM) research code. The influences of heterogeneity, bedding planes and their orientation with respect to loading on...
Research
Full-text available
This manuscript discusses the implementation of the Giovanni Grasselli shear strength criterion for rock joints inside a combined finite-discrete element method code. The relevance of the criterion, its formulation, and application by a simple case study are presented.
Conference Paper
Full-text available
In recent years, analyses based on the hybrid finite-discrete element method (FDEM) have been shown to provide a realistic representation of rock deformation and fracturing processes at laboratory and engineering scales. However, the ability to model linear rock reinforcement elements within FDEM has been largely limited. Through a collaborative re...
Conference Paper
Full-text available
Numerical simulations are widely adopted in the design of several types of rock structures, including tunnels, caverns, rock cuts, and open pit and underground mines. In recent years, analyses based on the hybrid finite-discrete element method (FDEM) have been shown to provide a realistic representation of rock mass deformation and fracturing proce...
Conference Paper
Full-text available
The goal of this paper is to present recent advances in the field of hydraulic fracturing modelling. In particular, a novel, fully 3D, hybrid finite-discrete element method (FDEM) approach was developed to numerically simulate fluid-pressure-driven fracturing. The effectiveness of the new approach is illustrated by simulating fracture nucleation an...
Conference Paper
Full-text available
Numerous research studies have shown that clay rock formations exhibit favourable characteristics for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation damaged zone (EDZ) around the...
Article
Full-text available
Hydraulic fracturing (HF) technique has been extensively used for the exploitation of unconventional oil and gas reservoirs. HF enhances the connectivity of less permeable oil and gas-bearing rock formations by fluid injection, which creates an interconnected fracture network and increases the hydrocarbon production. Meanwhile, microseismic (MS) mo...
Conference Paper
Full-text available
In this study, the hybrid Finite-Discrete Element Method (FEMDEM or FDEM) is used to investigate the influence of the rock fabric (e.g., joint sets and faults) on the mechanical response of rock masses in practical rock engineering problems. The first case study showcased focuses on the effects of pre-existing, cohesive discrete fracture networks (...
Conference Paper
Full-text available
Numerical simulations were carried out in support of geotechnical design for a shaft and loading pocket developed through soft, talc-rich squeezing ultramafic rock. The calibrated model was then used to predict the ground response when developing the loading pocket and the shaft below the loading pocket. The model results were used to assist in the...
Chapter
Full-text available
Experimental evidence based on microseismic data clearly show that fluid-pressure-driven fractures interact with preexisting discontinuities, thus highlighting the strong influence of rock mass structures on hydraulic fracture development. However, these mechanisms are not well accounted for by analytical models and conventional continuum-based num...
Article
Pressure-driven fracturing, also known as hydraulic fracturing, is a process widely used for developing geothermal resources, extracting hydrocarbons from unconventional reservoirs such as tight sandstone and shale formations, as well as for preconditioning the rock-mass during deep mining operations. While the overall process of pressure-driven fr...
Article
Stress waves, known as acoustic emissions (AEs), are released by localized inelastic deformation events during the progressive failure of brittle rocks. Although several numerical models have been developed to simulate the deformation and damage processes of rocks, such as non-linear stress-strain behaviour and localization of failure, only a limit...
Thesis
Full-text available
The mechanical response of geomaterials is highly influenced by geometrical and material heterogeneity. To date, most modelling practices consider heterogeneity qualitatively and the choice of input parameters can be subjective. In this study, a novel approach to combine detailed micro-scale characterization with modelling of heterogeneous geomater...
Article
Full-text available
The mechanical response of geomaterials is highly influenced by geometrical and material heterogeneity. To date, most modeling practices consider heterogeneity qualitatively and their choice of input parameters can be subjective. In this study, a novel approach to combine a detailed micro-scale characterization with modeling of heterogeneous geomat...
Conference Paper
Full-text available
The present paper summarizes the work done on developing and validating the use of a hybrid Finite - Discrete Element (FEMDEM) code for modelling slope instability processes. The main advantages of the FEMDEM method are the ability (i) to analyze the slope failure without assuming any mode or mechanism a priori, and (ii) to explicitly model the pos...
Article
Numerical modelling of a discontinuous medium has gained much popularity in recent decades. The combined finite-discrete element method (FEM/DEM) is a state-of-the-art numerical modelling technique pioneered in the mid-1990s. Y2D is a robust two-dimensional FEM/DEM research code developed by Munjiza in 2004. The major limitations of this code are (...
Article
This paper presents a study performed to evaluate the feasibility of implementing a series of heating rods within a zero-valent iron permeable reactive barrier (ZVI-PRB) to enhance the conventional design of PRBs, and thus to improve the barrier’s removal efficiency, and reduce construction and reactive material costs. A numerical modeling approach...
Article
Full-text available
This manuscript discusses the implementation of the Giovanni Gras-selli shear strength criterion for rock joints inside a combined finite-discrete element method code. The relevance of the criterion, its for-mulation, and application by a simple case study are presented.

Network

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Projects

Projects (2)
Project
Ultimate goal of this project is to provide critical rock mechanics input into the safety analyses of a deep geological repository for nuclear waste by carrying out physics-based, numerical simulations of the expected EDZ creation and evolution.
Project
This R&D project focuses on the development, implementation and validation of a 3D geomechanical simulation software based on the finite-discrete element method (FDEM). With this software, named Irazu, the parallel processing power of general-purpose graphics processing units (GPGPUs) is leveraged to gain significant computational performance boosts compared to existing sequential FDEM codes.