Hasan Ghasemzadeh - Profile on Academia.edu (original) (raw)
Papers by Hasan Ghasemzadeh
Stress waves contain useful information about the properties of porous materials; they can be rec... more Stress waves contain useful information about the properties of porous materials; they can be recovered through different non-destructive testing methods such as crosswell, vertical seismic profile, borehole logging as well as sonic tests. In all these methods, it is crucial to assess the effects of frequency on wave attributes including velocity and intrinsic attenuation. The dependency of permeability on frequency which is known as dynamic permeability and its effects on wave attributes of compressional waves are investigated in the present paper. Utilizing the dispersion relation derived for compressional waves, it is shown how the velocity and intrinsic attenuation of waves propagated in water saturated sand may be influenced by dynamic permeability. In low frequency range (viscous dominated flow regime), the dynamic permeability behaves like Darcy steady-state permeability and its effects on wave attributes are negligible. However, deviations from Darcy permeability start to oc...
Experimental study of sulfuric acid effects on hydro-mechanical properties of oxide copper heap soils
Minerals Engineering
Abstract Several mechanisms contribute to changes in the performance of oxide copper heaps. These... more Abstract Several mechanisms contribute to changes in the performance of oxide copper heaps. These include physical, biological, chemical and thermal interactions between sulfuric acid and the formation of soil particles. A series of experimental studies was conducted by simulating the column leaching process in the laboratory. The leaching of selected gravel and crushed copper oxide ores from two copper mines was carried out to measure their permeability and strength. The influence of effective parameters on gravel clogging was studied and the clogging coefficient was estimated with time. Furthermore, the ratio of particle reduction (RPR) caused by acid seepage was evaluated and an equation for the internal friction angle of ore particles over time was generated. The present study shows significant reductions of gravel permeability (28% after five months leaching) and friction angle of ore particles (25% after eight months leaching). The effects of sulfuric acid flow on the hydro-mechanical properties of oxide copper heap soils could enhance the accuracy of slope stability design and drainage layers design in industrial heap leaching systems.
A new insight into the analysis of plane elasticity with coupling of numerical manifold and boundary element methods
Engineering Analysis with Boundary Elements
Abstract In this research, a combination of the numerical manifold method (NMM) and boundary elem... more Abstract In this research, a combination of the numerical manifold method (NMM) and boundary element method (BEM) is presented for solving plane elasticity problems to benefit from the advantages of both methods. For this goal, the domain of the problems is divided into two regions, each region is analyzed separately, and finally, equilibrium and compatibility conditions are controlled in the interface by the iteration method. 1D quadratic boundary elements and 2D quadratic, cubic and quartic ones in the form of triangular shapes are utilized in the boundary element and manifold methods, respectively. The proposed method is verified by calculating the displacements and stresses resulting from the application of static loads in five different numerical problems. Comparison of the numerical results shows that the suggested method is very efficient and accurate.
Linnaeus Eco-Tech
Many environmental issues involve transport of contaminants in unsaturated porous soil media. Uns... more Many environmental issues involve transport of contaminants in unsaturated porous soil media. Unsaturated flow plays a significant role in wastewater infiltration and treatment. Transport of contaminants in unsaturated porous subsurface media is of significant importance due to the risks which contaminants pose to the environment. Mechanics of unsaturated soils is perhaps the most important issue in prediction of unsaturated flow including contaminant transport in the environment. The SWCC, “soil water characteristic curve”, can be used to determine various characteristics of the unsaturated soil media. In fact, it illustrates the relationship between soil suction and moisture content. Experimental methods for assessment of the SWCC are often time consuming and expensive. The SWCC can be estimated using specific characteristics of soils to avoid the costs of experimental methods. This paper aims at demonstrating that the SWCC for cohesive soils can be estimated using the PI, fine co...
Soils and Foundations
A coupled elastoplastic constitutive model is presented for describing the hydraulic and mechanic... more A coupled elastoplastic constitutive model is presented for describing the hydraulic and mechanical behavior of unsaturated soils. The model is capable of considering the influence of irreversible changes in water saturation on the mechanical behavior and plastic deformation on hydraulic behavior. The mechanical and hydraulic behaviors are captured using the subloading surface and bounding surface plasticity frameworks, respectively. The coupling between hydraulic and mechanical behaviors is established using intergranular stress concept in addition to appropriate coupled hardening rules. Attention is also given to the movement of soil water characteristic curve due to the plastic deformation. Model predictions for some unsaturated soil samples are compared with experimental data, and reasonable agreement is achieved.
The Effect of Diesel Fuel Pollution on the Efficiency of Soil Stabilization Method
Geotechnical and Geological Engineering, 2016
Chemical soil stabilization method can be applied as a remediation technique for contaminated soi... more Chemical soil stabilization method can be applied as a remediation technique for contaminated soils. Since stabilization method can improve the soil geotechnical properties, the effect of contamination should be investigated on soil strength improvement with this method. This paper studies the effect of different additives such as lime, cement, rice husk ash and RRP-235 Special on the geotechnical properties of a diesel fuel contaminated kaolinite. A series of unconfined compressive strength and direct shear tests were performed on the contaminated kaolinite stabilized with additives in the amounts of 1, 3 and 5% by soil dry weight. Results showed that an increase in diesel fuel as contaminant up to 10% by dry weight of the soil had adverse effects on lime and rice husk ash stabilized soil strength and cohesion, while it increased the strength and cohesion of cement stabilized soil. The friction angle of all the lime, cement and rice husk ash stabilized samples was decreased with increasing the contaminant. An increase in RRP-235 Special had no impact on the soil strength properties.
Upper bound solution for ultimate bearing capacity with a non-linear Hoek–Brown failure criterion
Rock Stress and Earthquakes, 2010
Hydraulic fracturing had been a widely applied method of measuring stresses in a drilled borehole... more Hydraulic fracturing had been a widely applied method of measuring stresses in a drilled borehole. During the test procedure, induced forces due to the interaction between fluid flow and rock blocks deformation overcome the in-situ least stress. Thus the coupled hydromechanical behavior of rocks having pre-defined joints should be considered. In order to model the process, an interactive computer program was developed. Through a numerical analysis, at first, fluid flow forces were calculated by Extended Pressure (EP) method. Then the coupled influence of fluid on mechanical behavior of rock blocks is included using Discontinuous Deformation Analysis (DDA). The procedure was used to simulate hydraulic tests on pre-existing fractures (HTPF). Finally having pressure-time records, the inverse calculation of in-situ stresses are compared with conventional method. The results have a reasonable coincidence.
Applied Mathematical Modelling
In this paper, a fully coupled finite volume-finite element model for a deforming porous medium i... more In this paper, a fully coupled finite volume-finite element model for a deforming porous medium interacting with the flow of two immiscible pore fluids is presented. The basic equations describing the system are derived based on the averaging theory. Applying the standard Galerkin finite element method to solve this system of partial differential equations does not conserve mass locally. A non-conservative method may cause some accuracy and stability problems. The control volume based finite element technique that satisfies local mass conservation of the flow equations can be an appropriate alternative. Full coupling of control volume based finite element and the standard finite element techniques to solve the multiphase flow and geomechanical equilibrium equations is the main goal of this paper. The accuracy and efficiency of the method are verified by studying several examples for which analytical or numerical solutions are available. The effect of mesh orientation is investigated by simulating a benchmark water-flooding problem. A representative example is also presented to demonstrate the capability of the model to simulate the behavior in heterogeneous porous media.
Nonlinear behavior of geological and engineered barriers
Effects of A low-carbon emission additive on mechanical properties of fine-grained soil under freeze-thaw cycles
Journal of Cleaner Production
Effects of thermal cycles on microstructural and functional properties of nano treated clayey soil
Engineering Geology
Numerical Methods in Civil Engineering
Previous research on bracing members show that the ductility of bracing members is compromised du... more Previous research on bracing members show that the ductility of bracing members is compromised due to the buckling phenomena. Therefore, many researchers have tried to use special considerations to increase the fracture life of bracing members. Some of these recommendations such as increasing the slenderness ratio, using lower width to thickness ratio, increasing the out-of-plane stiffness of middle connection to increase the fracture life of the bracing members can be used in seismic upgrading of bracing members. In this paper, the buckling behavior of a special type of concentrically braced frame termed as yielding damped braced core is investigated for different percentage of central core. Empirical studies shows that separation of X-braces by central frame, influence the buckling behavior of the system and leads to occurrence of buckling in second mode shape in accordance with two half-sine wave. The theoretical studies shows that the buckling strength of the system increases in proportion to increase in central core rigidity. Using more flexible central core, results in increase the possibility of instability and vice versa. Hence, to enhance the buckling behavior of the system, it is strongly recommended to use a central core with proper rigidity .
Canadian Journal of Soil Science
Bearing capacity is often calculated in dry or saturated conditions, leading to overconservative ... more Bearing capacity is often calculated in dry or saturated conditions, leading to overconservative designs, for a wide range of climates in the world. Extensive researches show that bearing capacity is significantly affected by the soil matric suction. However, in most of the presented models, uniform (and sometimes linear) suction distributions are taken into account for computing the bearing capacity. Also, there is no exact solution in the residual zone of unsaturation. In the present study, a simple method is proposed to predict the bearing capacity of footings placed on unsaturated soil, using the limit equilibrium concept. Linear and uniform variations of matric suction are considered in computations, as well as the nonlinear suction distribution. The framework of the proposed model is analogous to Terzaghi’s equation, and a novel factor is developed, during calculations, as the suction bearing capacity factor. In the case of full saturation, the proposed model is simplified to ...
An elastoplastic model for oil reservoirs using multi scale and adaptive mesh refinement methods
International Journal for Multiscale Computational Engineering
Investigation of Soil Active Wedge Angle with Linear Matric Suction Distribution Below the Footing
International Journal of Civil Engineering
Numerical Analysis of Pile–Soil–Pile Interaction in Pile Groups with Batter Piles
Geotechnical and Geological Engineering
Effect of diesel-contamination on geotechnical properties of illite soil
Engineering Geology
Stress waves contain useful information about the properties of porous materials; they can be rec... more Stress waves contain useful information about the properties of porous materials; they can be recovered through different non-destructive testing methods such as crosswell, vertical seismic profile, borehole logging as well as sonic tests. In all these methods, it is crucial to assess the effects of frequency on wave attributes including velocity and intrinsic attenuation. The dependency of permeability on frequency which is known as dynamic permeability and its effects on wave attributes of compressional waves are investigated in the present paper. Utilizing the dispersion relation derived for compressional waves, it is shown how the velocity and intrinsic attenuation of waves propagated in water saturated sand may be influenced by dynamic permeability. In low frequency range (viscous dominated flow regime), the dynamic permeability behaves like Darcy steady-state permeability and its effects on wave attributes are negligible. However, deviations from Darcy permeability start to oc...
Experimental study of sulfuric acid effects on hydro-mechanical properties of oxide copper heap soils
Minerals Engineering
Abstract Several mechanisms contribute to changes in the performance of oxide copper heaps. These... more Abstract Several mechanisms contribute to changes in the performance of oxide copper heaps. These include physical, biological, chemical and thermal interactions between sulfuric acid and the formation of soil particles. A series of experimental studies was conducted by simulating the column leaching process in the laboratory. The leaching of selected gravel and crushed copper oxide ores from two copper mines was carried out to measure their permeability and strength. The influence of effective parameters on gravel clogging was studied and the clogging coefficient was estimated with time. Furthermore, the ratio of particle reduction (RPR) caused by acid seepage was evaluated and an equation for the internal friction angle of ore particles over time was generated. The present study shows significant reductions of gravel permeability (28% after five months leaching) and friction angle of ore particles (25% after eight months leaching). The effects of sulfuric acid flow on the hydro-mechanical properties of oxide copper heap soils could enhance the accuracy of slope stability design and drainage layers design in industrial heap leaching systems.
A new insight into the analysis of plane elasticity with coupling of numerical manifold and boundary element methods
Engineering Analysis with Boundary Elements
Abstract In this research, a combination of the numerical manifold method (NMM) and boundary elem... more Abstract In this research, a combination of the numerical manifold method (NMM) and boundary element method (BEM) is presented for solving plane elasticity problems to benefit from the advantages of both methods. For this goal, the domain of the problems is divided into two regions, each region is analyzed separately, and finally, equilibrium and compatibility conditions are controlled in the interface by the iteration method. 1D quadratic boundary elements and 2D quadratic, cubic and quartic ones in the form of triangular shapes are utilized in the boundary element and manifold methods, respectively. The proposed method is verified by calculating the displacements and stresses resulting from the application of static loads in five different numerical problems. Comparison of the numerical results shows that the suggested method is very efficient and accurate.
Linnaeus Eco-Tech
Many environmental issues involve transport of contaminants in unsaturated porous soil media. Uns... more Many environmental issues involve transport of contaminants in unsaturated porous soil media. Unsaturated flow plays a significant role in wastewater infiltration and treatment. Transport of contaminants in unsaturated porous subsurface media is of significant importance due to the risks which contaminants pose to the environment. Mechanics of unsaturated soils is perhaps the most important issue in prediction of unsaturated flow including contaminant transport in the environment. The SWCC, “soil water characteristic curve”, can be used to determine various characteristics of the unsaturated soil media. In fact, it illustrates the relationship between soil suction and moisture content. Experimental methods for assessment of the SWCC are often time consuming and expensive. The SWCC can be estimated using specific characteristics of soils to avoid the costs of experimental methods. This paper aims at demonstrating that the SWCC for cohesive soils can be estimated using the PI, fine co...
Soils and Foundations
A coupled elastoplastic constitutive model is presented for describing the hydraulic and mechanic... more A coupled elastoplastic constitutive model is presented for describing the hydraulic and mechanical behavior of unsaturated soils. The model is capable of considering the influence of irreversible changes in water saturation on the mechanical behavior and plastic deformation on hydraulic behavior. The mechanical and hydraulic behaviors are captured using the subloading surface and bounding surface plasticity frameworks, respectively. The coupling between hydraulic and mechanical behaviors is established using intergranular stress concept in addition to appropriate coupled hardening rules. Attention is also given to the movement of soil water characteristic curve due to the plastic deformation. Model predictions for some unsaturated soil samples are compared with experimental data, and reasonable agreement is achieved.
The Effect of Diesel Fuel Pollution on the Efficiency of Soil Stabilization Method
Geotechnical and Geological Engineering, 2016
Chemical soil stabilization method can be applied as a remediation technique for contaminated soi... more Chemical soil stabilization method can be applied as a remediation technique for contaminated soils. Since stabilization method can improve the soil geotechnical properties, the effect of contamination should be investigated on soil strength improvement with this method. This paper studies the effect of different additives such as lime, cement, rice husk ash and RRP-235 Special on the geotechnical properties of a diesel fuel contaminated kaolinite. A series of unconfined compressive strength and direct shear tests were performed on the contaminated kaolinite stabilized with additives in the amounts of 1, 3 and 5% by soil dry weight. Results showed that an increase in diesel fuel as contaminant up to 10% by dry weight of the soil had adverse effects on lime and rice husk ash stabilized soil strength and cohesion, while it increased the strength and cohesion of cement stabilized soil. The friction angle of all the lime, cement and rice husk ash stabilized samples was decreased with increasing the contaminant. An increase in RRP-235 Special had no impact on the soil strength properties.
Upper bound solution for ultimate bearing capacity with a non-linear Hoek–Brown failure criterion
Rock Stress and Earthquakes, 2010
Hydraulic fracturing had been a widely applied method of measuring stresses in a drilled borehole... more Hydraulic fracturing had been a widely applied method of measuring stresses in a drilled borehole. During the test procedure, induced forces due to the interaction between fluid flow and rock blocks deformation overcome the in-situ least stress. Thus the coupled hydromechanical behavior of rocks having pre-defined joints should be considered. In order to model the process, an interactive computer program was developed. Through a numerical analysis, at first, fluid flow forces were calculated by Extended Pressure (EP) method. Then the coupled influence of fluid on mechanical behavior of rock blocks is included using Discontinuous Deformation Analysis (DDA). The procedure was used to simulate hydraulic tests on pre-existing fractures (HTPF). Finally having pressure-time records, the inverse calculation of in-situ stresses are compared with conventional method. The results have a reasonable coincidence.
Applied Mathematical Modelling
In this paper, a fully coupled finite volume-finite element model for a deforming porous medium i... more In this paper, a fully coupled finite volume-finite element model for a deforming porous medium interacting with the flow of two immiscible pore fluids is presented. The basic equations describing the system are derived based on the averaging theory. Applying the standard Galerkin finite element method to solve this system of partial differential equations does not conserve mass locally. A non-conservative method may cause some accuracy and stability problems. The control volume based finite element technique that satisfies local mass conservation of the flow equations can be an appropriate alternative. Full coupling of control volume based finite element and the standard finite element techniques to solve the multiphase flow and geomechanical equilibrium equations is the main goal of this paper. The accuracy and efficiency of the method are verified by studying several examples for which analytical or numerical solutions are available. The effect of mesh orientation is investigated by simulating a benchmark water-flooding problem. A representative example is also presented to demonstrate the capability of the model to simulate the behavior in heterogeneous porous media.
Nonlinear behavior of geological and engineered barriers
Effects of A low-carbon emission additive on mechanical properties of fine-grained soil under freeze-thaw cycles
Journal of Cleaner Production
Effects of thermal cycles on microstructural and functional properties of nano treated clayey soil
Engineering Geology
Numerical Methods in Civil Engineering
Previous research on bracing members show that the ductility of bracing members is compromised du... more Previous research on bracing members show that the ductility of bracing members is compromised due to the buckling phenomena. Therefore, many researchers have tried to use special considerations to increase the fracture life of bracing members. Some of these recommendations such as increasing the slenderness ratio, using lower width to thickness ratio, increasing the out-of-plane stiffness of middle connection to increase the fracture life of the bracing members can be used in seismic upgrading of bracing members. In this paper, the buckling behavior of a special type of concentrically braced frame termed as yielding damped braced core is investigated for different percentage of central core. Empirical studies shows that separation of X-braces by central frame, influence the buckling behavior of the system and leads to occurrence of buckling in second mode shape in accordance with two half-sine wave. The theoretical studies shows that the buckling strength of the system increases in proportion to increase in central core rigidity. Using more flexible central core, results in increase the possibility of instability and vice versa. Hence, to enhance the buckling behavior of the system, it is strongly recommended to use a central core with proper rigidity .
Canadian Journal of Soil Science
Bearing capacity is often calculated in dry or saturated conditions, leading to overconservative ... more Bearing capacity is often calculated in dry or saturated conditions, leading to overconservative designs, for a wide range of climates in the world. Extensive researches show that bearing capacity is significantly affected by the soil matric suction. However, in most of the presented models, uniform (and sometimes linear) suction distributions are taken into account for computing the bearing capacity. Also, there is no exact solution in the residual zone of unsaturation. In the present study, a simple method is proposed to predict the bearing capacity of footings placed on unsaturated soil, using the limit equilibrium concept. Linear and uniform variations of matric suction are considered in computations, as well as the nonlinear suction distribution. The framework of the proposed model is analogous to Terzaghi’s equation, and a novel factor is developed, during calculations, as the suction bearing capacity factor. In the case of full saturation, the proposed model is simplified to ...
An elastoplastic model for oil reservoirs using multi scale and adaptive mesh refinement methods
International Journal for Multiscale Computational Engineering
Investigation of Soil Active Wedge Angle with Linear Matric Suction Distribution Below the Footing
International Journal of Civil Engineering
Numerical Analysis of Pile–Soil–Pile Interaction in Pile Groups with Batter Piles
Geotechnical and Geological Engineering
Effect of diesel-contamination on geotechnical properties of illite soil
Engineering Geology