Papers by Shobeir Arshadnejad
Stress analysis for a rock medium is essential for determination of stress concentration between ... more Stress analysis for a rock medium is essential for determination of stress concentration between two neighboring circular holes and prediction of fracture behavior. When two neighboring circular holes in a hard rock medium such as granite are loaded internally by the pressure of a Non-Explosive Expansion Material (NEEM), stress concentration occurs between the holes which then causes the rock to fracture. In this study, Finite Element (FE) analysis using a Phase2 computer code was employed to study the stress concentration between two neighboring circular holes under internal pressure induced by the NEEM. The effects of different hole diameters and spacings, rock properties and NEEM pressures were analyzed, and the data obtained from numerical analysis and statistical studies were then used to develop two models. These models were then modified by using the FE data and polynomial regression analysis. The developed statistical models were shown to be in a very good agreement with the...
International Journal of Rock Mechanics and Mining Sciences
Bilateral no Input values Unilateral yes Calculated values Results Tunnel length (L total ): 552 ... more Bilateral no Input values Unilateral yes Calculated values Results Tunnel length (L total ): 552 (m) Tunnel Height (H): 7.5 (m) Tunnel Width (B): 9.3 (m) Height of eye's driver (h): 1.2 (m) → Accordance Distance : (d a ) → d a = 52 (m) Car speed (V): 80 (km/hr) 22.22 (m/s) Accordance time (t a ): 8 (s) → Length of supplementary cone: (L s ) → L s = 125 (m) Height of object (a): 0.3 (m) → Safety stop distance (d s ): 137 (m) Length of Threshold zone: (L th ) → L th = 46 (m) V wet road dry road (km/hr) (m) (m) (L en ) → L en = 125 (m) (L tr ) → L tr = 79 (m) (L i ) → L i = 381 (m) (L ex ) → L ex = 46 (m) ← L th L tr L i L tr L th ← → → L th L tr L i → 46 79 381 → Zonation of the tunnel's illustration in meter.
Advances in Geotechnical Infrastructure, 2013
Blast-induced vibration is one of the engineering and public concerns in civil engineering and mi... more Blast-induced vibration is one of the engineering and public concerns in civil engineering and mining projects. Peak particle velocity (PPV ) has been commonly adopted as a parameter to characterize ground vibration since 1950s. Most conventional empirical models relate PPV to a term called scaled-distance (SD) which depends the charge rate per delay and the distance between detonation and monitoring point. The PPV and SD are plotted in a logarithm-logarithm space and they are often fitted by a linear model despite the fact that the data could be quite scattered.
It can be seen clearly that information such as the properties of rocks and explosives was not taken into account in the empirical equation. However, these parameters could be substantially varied in a project over a large area (for instance a long tunnel). Over- or underestimation of PPV for a given SD is very uncommon. In this investigation, attempts have been made to consider of the effect of rock mass condition on PPV by incorporating a rock mass characterization index into the empirical model. A case study of tunnel blasting in granite with different rock mass quality ranges is used as an example. An empirical relations including the rock mass quality have been proposed and validated by the vibration data collected from the project. The results show less scattered plots of the data and a better prediction of PPV.
One of the new engineering techniques in the world is demolition by controlled
blasting operatio... more One of the new engineering techniques in the world is demolition by controlled
blasting operation. The method contains some mining engineering and civil engineering’s
techniques. They are the controlled blasting, proper selection of type and amount of
explosives, air-blast, ground vibrations and fly rock effects and structure analysis,
construction material properties, like mechanical strength of them. This paper has
subjected to control of air-blast in concrete structures. Sometimes intensity of air-blast
can due to fragment of windows and weak members of structures in faraway, if there are
strong winds and inversion. It is clear that control of air-blast is very important; therefore
four standards (USA, UK, Australia & Spain) for determining of allowable sound levels
have collected in the paper.
Author made 22 concrete columns and three blast holes were drilled in each column.
The hole spacings have selected independently. It means that blast of a hole does not
affect the on other holes. After each blasting, sound level in dB (A), distance and amount
of explosives in each period have recorded. Finally, the data were converted to
logarithmical form and analyzed by multiple regressions and was obtained an empirical
model. Correlation coefficient of the model shows that the model’s results are good
agreement with empirical data. The model can evaluates safety radius against to air-blast
in demolition operation of concrete structures.
One of the important requirements of big cities are demolishing of old buildings and
making some... more One of the important requirements of big cities are demolishing of old buildings and
making some new buildings. Demolition is a mixture of mining engineering and civil engineering
techniques. Fly rock and determination of safe distance is a main problem in demolition technique
that is considered in this paper. A physical modelling was used for this research. The model was
a brick chimney and was used three types of blasting mat in around of body chimney. The blasting
mat covered the drilling area. Usual specific charge for a brick wall with 35 cm (thickness) is 3.5
kg/m3 but specific charge was 2.45 kg/m3 by 32 mm drill holes, in the research. About 70 samples
were used for regression analysis. Three experimental models are presented by three parameters.
These parameters are mass of particles, throw distance and maximum bearing tensile of blasting
mats. For other value of blasting mat strength can be interpolated in the final diagram.
Takarrok gypsum is a small open pit mine. It is located in 85 km of south of Mashhad city in Iran... more Takarrok gypsum is a small open pit mine. It is located in 85 km of south of Mashhad city in Iran. Average thickness of ore
layer in the mine is about 25 m with 70 to 80 degree of dip. Bench height is 3.5 m and diameter of blast holes is 64 mm. Specific
gravity of rock (ore) is 2.2. An old qanat with about 10 m depth and 510 m length with 1.41 m2 cross section area is placed at vicinity
of the mine. Qanat is a small capacity water tunnel that was invented by Iranian people. The qanat is the most important water resource
of a village near of the mine, that its name is Takarrok. Some of heavy blasting operations in the mine, has caused the partial collapse
in the roof and walls of the qanat. Therefore, two main scopes are considered in this paper. First is control of ground vibration by
analytical methods and second is numerical modeling of the qanat in dynamic condition by Phase2 software. The results shows that for
stability of the qanat used are some delay in blasting operation and used are the concrete segment, simultaneously.
The Siah Bishe pumped storage project is now under construction. The investigation results, the s... more The Siah Bishe pumped storage project is now under construction. The investigation results, the stability analysis and the support
concept for the displacement chamber are discussed in this paper. The geometry of the transversal section and optimum maintenance
system have been designed with respect to the unique geological and shear zone conditions encountered in Siah Bishe. The displacement
chamber is arranged in sedimentary and volcanic rocks of Triasic and Jurasic ages. Length of the chamber is 50 m and the height is 10 m
with relatively north–south trend. The results of geo-engineering surveys and statistical joint-graphics of stereograms reveal at least three
discontinuity systems in the rock mass. The transversal section along the chamber was studied to analyze the stability of rock wedges
inside the chamber. The frequency and width of bedding parallel shear zones determined the final support concept. Special attention
was paid to the design of the transversal section so as to minimize the stress concentration in the critical regions of the wall, bottom
of the chamber and corners. The results of analyses show that the chamber is stable in static and dynamic condition with 20 cm thickness
of reinforced shotcrete, fully bonded rock bolt with 35 mm diameter, 3.5 m length and steel frame with 82 kg/m I section with 0.85 m
spacing.
Stress analysis for a rock medium is essential for determination of stress concentration between ... more Stress analysis for a rock medium is essential for determination of stress concentration between two neighboring
circular holes and prediction of fracture behavior. When two neighboring circular holes in a hard rock medium
such as granite are loaded internally by the pressure of a Non-Explosive Expansion Material (NEEM), stress
concentration occurs between the holes which then causes the rock to fracture. In this study, Finite Element (FE)
analysis using a Phase2 computer code was employed to study the stress concentration between two neighboring
circular holes under internal pressure induced by the NEEM. The effects of different hole diameters and spacings,
rock properties and NEEM pressures were analyzed, and the data obtained from numerical analysis and statistical
studies were then used to develop two models. These models were then modified by using the FE data and polynomial
regression analysis. The developed statistical models were shown to be in a very good agreement with the
FE analysis. Validation of the equations is only for the points located on the line passing through the centers of the
holes in the elastic state. Hence, the developed models can be used with confidence to determine stress distribution
and concentration factors around two neighboring circular holes, which are excavated in a hard -brittle rock
and loaded internally by the pressure induced from the NEEM.
Applying non-explosive expansion material (NEEM) is one of the
safest methods for rock fracturin... more Applying non-explosive expansion material (NEEM) is one of the
safest methods for rock fracturing, especially in a hard rock quarry.
An experimental study was conducted to determine the pressure
exerted by NEEM in a hole, which is necessary for analysing rock
fracturing, particularly in a numerical modelling. Stress distribution
was developed in a thick-wall cylinder in order to measure the
tangential strain on the external boundary. In the experiments, nine
pipes of different materials and varying diameters were selected and
then loaded internally with a general type of NEEM. Through
electrical strain gauges, the tangential strains were recorded on the
external boundary of the pipes.
The results obtained from these tests and existing data from
previous researchers were utilized for the statistical analysis. A new
experimentally-derived formula is proposed for determining the
pressure exerted by NEEM by multiple parameter regression with a
high correlation coefficient. The proposed model has a nonlinear
form with three independent parameters i.e. the hole diameter, the
time, and the modulus of elasticity of the material.
International Journal of …, Jan 1, 2011
The application of the non-explosive expansion material (NEEM) is widely used as the controlled f... more The application of the non-explosive expansion material (NEEM) is widely used as the controlled fracture method in quarry mining,
especially in hard rocks. The pressure of NEEM is an important parameter in causing rock fracture. An empirical model based on hole
spacing was developed to determine the pressure of NEEM in the rock fracture process. Primarily, the empirical model was developed by the
mathematical method, utilizing dimensional analysis. Then, the Phase2 code, which is based on the finite element method, was utilized to
predict crack growth in rocks. The results of numerical analysis show slight deviations from the empirical model. Hence, the polynomial regression
analysis was used to modify the model. Finally, the modified model shows a good agreement with the results gained from numerical
modeling.
Conference Presentations by Shobeir Arshadnejad
The mi is an important parameter to use of Hoek-Brown criterion. It can be estimated by triaxial ... more The mi is an important parameter to use of Hoek-Brown criterion. It can be estimated by triaxial compressive strength test but at many times in many projects there is no the result of the test. Then estimation of the mi is done by a reference’s table as a constant value. Elsewhere some empirical equations have been suggested in 1990s. But application of them are limit because of they are just for a few type of rocks and the equations are based on just uniaxial compressive strength of rocks. Thus all of rocks have been divided to three categories (Igneous, Sedimentary and Metamorphic) in this research and three empirical formulas have been suggested for the categories based on uni axial compressive strength (σci) and tensile strength (σt) of rocks by nonlinear regression. The equations have been obtained by combination of the two independent parameters in many different forms and used the try and error method to achieve the equations with high value of correlation coefficient. The data base consisted many data from original international researches and many data from Iranian tunneling projects. The models have high level accuracy and has been tried to cover most of rock types but the authors know that they can be better by new and larger collection of data in future.
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Papers by Shobeir Arshadnejad
It can be seen clearly that information such as the properties of rocks and explosives was not taken into account in the empirical equation. However, these parameters could be substantially varied in a project over a large area (for instance a long tunnel). Over- or underestimation of PPV for a given SD is very uncommon. In this investigation, attempts have been made to consider of the effect of rock mass condition on PPV by incorporating a rock mass characterization index into the empirical model. A case study of tunnel blasting in granite with different rock mass quality ranges is used as an example. An empirical relations including the rock mass quality have been proposed and validated by the vibration data collected from the project. The results show less scattered plots of the data and a better prediction of PPV.
blasting operation. The method contains some mining engineering and civil engineering’s
techniques. They are the controlled blasting, proper selection of type and amount of
explosives, air-blast, ground vibrations and fly rock effects and structure analysis,
construction material properties, like mechanical strength of them. This paper has
subjected to control of air-blast in concrete structures. Sometimes intensity of air-blast
can due to fragment of windows and weak members of structures in faraway, if there are
strong winds and inversion. It is clear that control of air-blast is very important; therefore
four standards (USA, UK, Australia & Spain) for determining of allowable sound levels
have collected in the paper.
Author made 22 concrete columns and three blast holes were drilled in each column.
The hole spacings have selected independently. It means that blast of a hole does not
affect the on other holes. After each blasting, sound level in dB (A), distance and amount
of explosives in each period have recorded. Finally, the data were converted to
logarithmical form and analyzed by multiple regressions and was obtained an empirical
model. Correlation coefficient of the model shows that the model’s results are good
agreement with empirical data. The model can evaluates safety radius against to air-blast
in demolition operation of concrete structures.
making some new buildings. Demolition is a mixture of mining engineering and civil engineering
techniques. Fly rock and determination of safe distance is a main problem in demolition technique
that is considered in this paper. A physical modelling was used for this research. The model was
a brick chimney and was used three types of blasting mat in around of body chimney. The blasting
mat covered the drilling area. Usual specific charge for a brick wall with 35 cm (thickness) is 3.5
kg/m3 but specific charge was 2.45 kg/m3 by 32 mm drill holes, in the research. About 70 samples
were used for regression analysis. Three experimental models are presented by three parameters.
These parameters are mass of particles, throw distance and maximum bearing tensile of blasting
mats. For other value of blasting mat strength can be interpolated in the final diagram.
layer in the mine is about 25 m with 70 to 80 degree of dip. Bench height is 3.5 m and diameter of blast holes is 64 mm. Specific
gravity of rock (ore) is 2.2. An old qanat with about 10 m depth and 510 m length with 1.41 m2 cross section area is placed at vicinity
of the mine. Qanat is a small capacity water tunnel that was invented by Iranian people. The qanat is the most important water resource
of a village near of the mine, that its name is Takarrok. Some of heavy blasting operations in the mine, has caused the partial collapse
in the roof and walls of the qanat. Therefore, two main scopes are considered in this paper. First is control of ground vibration by
analytical methods and second is numerical modeling of the qanat in dynamic condition by Phase2 software. The results shows that for
stability of the qanat used are some delay in blasting operation and used are the concrete segment, simultaneously.
concept for the displacement chamber are discussed in this paper. The geometry of the transversal section and optimum maintenance
system have been designed with respect to the unique geological and shear zone conditions encountered in Siah Bishe. The displacement
chamber is arranged in sedimentary and volcanic rocks of Triasic and Jurasic ages. Length of the chamber is 50 m and the height is 10 m
with relatively north–south trend. The results of geo-engineering surveys and statistical joint-graphics of stereograms reveal at least three
discontinuity systems in the rock mass. The transversal section along the chamber was studied to analyze the stability of rock wedges
inside the chamber. The frequency and width of bedding parallel shear zones determined the final support concept. Special attention
was paid to the design of the transversal section so as to minimize the stress concentration in the critical regions of the wall, bottom
of the chamber and corners. The results of analyses show that the chamber is stable in static and dynamic condition with 20 cm thickness
of reinforced shotcrete, fully bonded rock bolt with 35 mm diameter, 3.5 m length and steel frame with 82 kg/m I section with 0.85 m
spacing.
circular holes and prediction of fracture behavior. When two neighboring circular holes in a hard rock medium
such as granite are loaded internally by the pressure of a Non-Explosive Expansion Material (NEEM), stress
concentration occurs between the holes which then causes the rock to fracture. In this study, Finite Element (FE)
analysis using a Phase2 computer code was employed to study the stress concentration between two neighboring
circular holes under internal pressure induced by the NEEM. The effects of different hole diameters and spacings,
rock properties and NEEM pressures were analyzed, and the data obtained from numerical analysis and statistical
studies were then used to develop two models. These models were then modified by using the FE data and polynomial
regression analysis. The developed statistical models were shown to be in a very good agreement with the
FE analysis. Validation of the equations is only for the points located on the line passing through the centers of the
holes in the elastic state. Hence, the developed models can be used with confidence to determine stress distribution
and concentration factors around two neighboring circular holes, which are excavated in a hard -brittle rock
and loaded internally by the pressure induced from the NEEM.
safest methods for rock fracturing, especially in a hard rock quarry.
An experimental study was conducted to determine the pressure
exerted by NEEM in a hole, which is necessary for analysing rock
fracturing, particularly in a numerical modelling. Stress distribution
was developed in a thick-wall cylinder in order to measure the
tangential strain on the external boundary. In the experiments, nine
pipes of different materials and varying diameters were selected and
then loaded internally with a general type of NEEM. Through
electrical strain gauges, the tangential strains were recorded on the
external boundary of the pipes.
The results obtained from these tests and existing data from
previous researchers were utilized for the statistical analysis. A new
experimentally-derived formula is proposed for determining the
pressure exerted by NEEM by multiple parameter regression with a
high correlation coefficient. The proposed model has a nonlinear
form with three independent parameters i.e. the hole diameter, the
time, and the modulus of elasticity of the material.
especially in hard rocks. The pressure of NEEM is an important parameter in causing rock fracture. An empirical model based on hole
spacing was developed to determine the pressure of NEEM in the rock fracture process. Primarily, the empirical model was developed by the
mathematical method, utilizing dimensional analysis. Then, the Phase2 code, which is based on the finite element method, was utilized to
predict crack growth in rocks. The results of numerical analysis show slight deviations from the empirical model. Hence, the polynomial regression
analysis was used to modify the model. Finally, the modified model shows a good agreement with the results gained from numerical
modeling.
Conference Presentations by Shobeir Arshadnejad
It can be seen clearly that information such as the properties of rocks and explosives was not taken into account in the empirical equation. However, these parameters could be substantially varied in a project over a large area (for instance a long tunnel). Over- or underestimation of PPV for a given SD is very uncommon. In this investigation, attempts have been made to consider of the effect of rock mass condition on PPV by incorporating a rock mass characterization index into the empirical model. A case study of tunnel blasting in granite with different rock mass quality ranges is used as an example. An empirical relations including the rock mass quality have been proposed and validated by the vibration data collected from the project. The results show less scattered plots of the data and a better prediction of PPV.
blasting operation. The method contains some mining engineering and civil engineering’s
techniques. They are the controlled blasting, proper selection of type and amount of
explosives, air-blast, ground vibrations and fly rock effects and structure analysis,
construction material properties, like mechanical strength of them. This paper has
subjected to control of air-blast in concrete structures. Sometimes intensity of air-blast
can due to fragment of windows and weak members of structures in faraway, if there are
strong winds and inversion. It is clear that control of air-blast is very important; therefore
four standards (USA, UK, Australia & Spain) for determining of allowable sound levels
have collected in the paper.
Author made 22 concrete columns and three blast holes were drilled in each column.
The hole spacings have selected independently. It means that blast of a hole does not
affect the on other holes. After each blasting, sound level in dB (A), distance and amount
of explosives in each period have recorded. Finally, the data were converted to
logarithmical form and analyzed by multiple regressions and was obtained an empirical
model. Correlation coefficient of the model shows that the model’s results are good
agreement with empirical data. The model can evaluates safety radius against to air-blast
in demolition operation of concrete structures.
making some new buildings. Demolition is a mixture of mining engineering and civil engineering
techniques. Fly rock and determination of safe distance is a main problem in demolition technique
that is considered in this paper. A physical modelling was used for this research. The model was
a brick chimney and was used three types of blasting mat in around of body chimney. The blasting
mat covered the drilling area. Usual specific charge for a brick wall with 35 cm (thickness) is 3.5
kg/m3 but specific charge was 2.45 kg/m3 by 32 mm drill holes, in the research. About 70 samples
were used for regression analysis. Three experimental models are presented by three parameters.
These parameters are mass of particles, throw distance and maximum bearing tensile of blasting
mats. For other value of blasting mat strength can be interpolated in the final diagram.
layer in the mine is about 25 m with 70 to 80 degree of dip. Bench height is 3.5 m and diameter of blast holes is 64 mm. Specific
gravity of rock (ore) is 2.2. An old qanat with about 10 m depth and 510 m length with 1.41 m2 cross section area is placed at vicinity
of the mine. Qanat is a small capacity water tunnel that was invented by Iranian people. The qanat is the most important water resource
of a village near of the mine, that its name is Takarrok. Some of heavy blasting operations in the mine, has caused the partial collapse
in the roof and walls of the qanat. Therefore, two main scopes are considered in this paper. First is control of ground vibration by
analytical methods and second is numerical modeling of the qanat in dynamic condition by Phase2 software. The results shows that for
stability of the qanat used are some delay in blasting operation and used are the concrete segment, simultaneously.
concept for the displacement chamber are discussed in this paper. The geometry of the transversal section and optimum maintenance
system have been designed with respect to the unique geological and shear zone conditions encountered in Siah Bishe. The displacement
chamber is arranged in sedimentary and volcanic rocks of Triasic and Jurasic ages. Length of the chamber is 50 m and the height is 10 m
with relatively north–south trend. The results of geo-engineering surveys and statistical joint-graphics of stereograms reveal at least three
discontinuity systems in the rock mass. The transversal section along the chamber was studied to analyze the stability of rock wedges
inside the chamber. The frequency and width of bedding parallel shear zones determined the final support concept. Special attention
was paid to the design of the transversal section so as to minimize the stress concentration in the critical regions of the wall, bottom
of the chamber and corners. The results of analyses show that the chamber is stable in static and dynamic condition with 20 cm thickness
of reinforced shotcrete, fully bonded rock bolt with 35 mm diameter, 3.5 m length and steel frame with 82 kg/m I section with 0.85 m
spacing.
circular holes and prediction of fracture behavior. When two neighboring circular holes in a hard rock medium
such as granite are loaded internally by the pressure of a Non-Explosive Expansion Material (NEEM), stress
concentration occurs between the holes which then causes the rock to fracture. In this study, Finite Element (FE)
analysis using a Phase2 computer code was employed to study the stress concentration between two neighboring
circular holes under internal pressure induced by the NEEM. The effects of different hole diameters and spacings,
rock properties and NEEM pressures were analyzed, and the data obtained from numerical analysis and statistical
studies were then used to develop two models. These models were then modified by using the FE data and polynomial
regression analysis. The developed statistical models were shown to be in a very good agreement with the
FE analysis. Validation of the equations is only for the points located on the line passing through the centers of the
holes in the elastic state. Hence, the developed models can be used with confidence to determine stress distribution
and concentration factors around two neighboring circular holes, which are excavated in a hard -brittle rock
and loaded internally by the pressure induced from the NEEM.
safest methods for rock fracturing, especially in a hard rock quarry.
An experimental study was conducted to determine the pressure
exerted by NEEM in a hole, which is necessary for analysing rock
fracturing, particularly in a numerical modelling. Stress distribution
was developed in a thick-wall cylinder in order to measure the
tangential strain on the external boundary. In the experiments, nine
pipes of different materials and varying diameters were selected and
then loaded internally with a general type of NEEM. Through
electrical strain gauges, the tangential strains were recorded on the
external boundary of the pipes.
The results obtained from these tests and existing data from
previous researchers were utilized for the statistical analysis. A new
experimentally-derived formula is proposed for determining the
pressure exerted by NEEM by multiple parameter regression with a
high correlation coefficient. The proposed model has a nonlinear
form with three independent parameters i.e. the hole diameter, the
time, and the modulus of elasticity of the material.
especially in hard rocks. The pressure of NEEM is an important parameter in causing rock fracture. An empirical model based on hole
spacing was developed to determine the pressure of NEEM in the rock fracture process. Primarily, the empirical model was developed by the
mathematical method, utilizing dimensional analysis. Then, the Phase2 code, which is based on the finite element method, was utilized to
predict crack growth in rocks. The results of numerical analysis show slight deviations from the empirical model. Hence, the polynomial regression
analysis was used to modify the model. Finally, the modified model shows a good agreement with the results gained from numerical
modeling.