Davood Mohammadi - Academia.edu (original) (raw)

Papers by Davood Mohammadi

Periodica polytechnica. Civil engineering/Periodica polytechnica. Civil engineering (Online), Jul 10, 2024

Research Square (Research Square), Apr 8, 2024

This research investigates acoustic emission (AE) phenomena during shear failure of layered rock ... more This research investigates acoustic emission (AE) phenomena during shear failure of layered rock bridges under different normal stresses using experimental punch tests and numerical simulation. Firstly, particle ow code (PFC) was calibrated by UCS and Brazilian experimental test results and then the shear behavior of the numerical model was veri ed by experimental punch test outputs. Finally, acoustic phenomena during shear failure of layered rock bridges were discussed. Rectangular specimens were utilized, incorporating a combination of different layers. These layers included a pairing of soft and hard materials, as well as variations such as a two-layered model comprising hard gypsum and soft gypsum. Furthermore, three-layered models were examined, featuring a soft interlayer in one case and a hard interlayer in another. Additionally, a four-layered model was employed for the investigation. In each model, two vertical edge ssures were introduced, with ssure lengths set at 20, 40, and 60 mm. The angle between bedding layers and shear loading direction was 90°. The results indicate that cracks initiate at the notch tip and propagate vertically until they meet the upper boundary. The frequency of signi cant Acoustic hits is tied to factors like crack initiation and material properties. Increasing the number of layers in the specimen leads to more Acoustic hits. The sequence of Acoustic hits between major hits is in uenced by parameters such as bedding number and material properties. This correlation is attributed to different gypsum types on the shear surface. The ndings from numerical bedding models mirror those from physical samples.

In the present study, the effects of angle and brittleness of interlayers on the shear failure be... more In the present study, the effects of angle and brittleness of interlayers on the shear failure behavior of notched bedding rock have been scrutinized using experimental shear tests and particle flow code (PFC) simulation. Notched bedding models with dimensions of 20 cm × 24 cm × 5 cm containing soft interlayer and hard interlayer were prepared. The ratio of compressive strength to tensile strength in soft gypsum and hard gypsum are 12 and 7.8, respectively. The layer angel changed from 0° to 90° with an increment of 15°. The lengths of notches in each model are similar and were equal to 20 mm, 40 mm, and 60 mm. Models were tested by Punch shear by displacement loading rates of 0.05 mm/min. Results showed that pure tensile fracture was developed from the tip of the notch, and propagated in the direction of the shear loading axis till coalescence with the model boundary. Whereas soft brittle gypsum has less deformability in comparison to hard ductile gypsum therefore the continuity of shear displacement associated with crack growth in soft interlayer was less than that in hard interlayer. Also, soft brittle gypsum has less shear strength in comparison to hard ductile gypsum therefore the shear strength of bedding rock has maximum value when hard ductile gypsum was occupied more percentage of shear surfaces. The failure mechanism was alike in both the numerical simulation and the experimental test.

Bulletin of Engineering Geology and the Environment, Sep 7, 2014

Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by empl... more Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by employing the New Austrian Tunnelling Method in the Tehran metropolitan area, by several approaches, such as the semi-empirical method, linear and non-linear multiple regression method (MR), and finally by a programming Multi-Layered Perception (MLP) with a Back Propagation training algorithm. The geology at the site is mostly composed of conglomerates with pebbles and boulders. The maximum settlement is estimated based on the semiempirical relations represented by several researchers. The input data set for MR and MLP models are soil characteristic [cohesion (C), internal friction angle (u), elasticity modulus (E) and unit weight (Gs)], excavation depth (Z 0 ), soil type (S t ) and PLAXIS 2D settlement prediction by the Hardening Soil model. Among all MLP and MR models, MLP models and especially model 6, the model based on E, Z, u, Gs, C and S t variables, seem to be reliable and agreeable to numerical results. The performance of MR, MLP, and optimized MLP models are evaluated by comparing statistic parameters, including coefficient correlations (R), root mean square error (RMSE), mean error (ME) and Akaike information criterion (AIC), whose values for model 6 are 0.93, 1.66, 0.89 and 13.16, respectively. Therefore, compared to other MLP and MR models, the optimized MLP model shows a relatively high level of accuracy. Additionally, model 4, the model based on E, Z, u and Gs variables, shows in MLP analysis that unit weight does not have significant effect on maximum settlement.

Scientific Quarterly Journal of Iranian Association of Engineering Geology, Nov 21, 2020

To identify natural behavior of rocks under the similar moisture conditions, two saturation metho... more To identify natural behavior of rocks under the similar moisture conditions, two saturation methods of under atmospheric pressure conditions or vacuum pressure are usually used. In the method of vacuum pressure, the values of vacuum pressure Pvac as well as the time of applying this pressure Tvac are two effective parameters. In this study, the saturation method of rock, especially soluble ones such as gypsum and anhydrite, have been studied. The results of the experiments were analyzed in terms of sensitivity for four parameters of dry vacuum pressure Pvac(dry), wet vacuum pressure Pvac(wet) and the time of applying each one (Tvac(wet), Tvac(dry)). The results showed that by increasing Pvac(wet), the percentage of water absorption has been increased and the samples generally gain more than 95% of their increased weight after 4 days of applying wet vacuum and they can be practically assumed to be saturated. Applying dry vacuum Pvac(dry) before wet vacuum Pvac(wet), increases the weight of most samples after applying Pvac(wet). In case of gypsum-anhydrite rocks, the experiment showed that applying dry pressure equivalent to -0.5 atmospheres (atm) and to 5 hours (Pvac(wet) = -0.5 atm, Tvac(dry)) = 5h) propose ideal results.

Scientific Quarterly Journal of Iranian Association of Engineering Geology, Feb 19, 2013

The Extended Dynamic Cone Penetration (EDCP) test supplemented by measurement of torque (EDCP-T) ... more The Extended Dynamic Cone Penetration (EDCP) test supplemented by measurement of torque (EDCP-T) may be used to obtain a direct measurement of unit skin friction ( s f ) between the cone section and the surrounding soil. The test is performed after completion of the EDCP test. In order to perform the EDCP-T, the EDCP device is rotated after driving the rod and maximum torque is measured using a calibrated torque wrench that is connected to the top of the EDCP. The EDCP-T test results at 3 sites are presented. The results show that the unit skin friction values obtained from the EDCP-T generally correlate well with normalized blows for 30 cm penetration of the EDCP tip (NEDCP(n)). The results may be valuable for preliminary estimation of unit skin friction of the driven piles. Keywords– Penetration, driven piles, rod friction, geotechnical properties, coarse grained, fine grained

Bulletin of Engineering Geology and the Environment, 2014

Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by empl... more Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by employing the New Austrian Tunnelling Method in the Tehran metropolitan area, by several approaches, such as the semi-empirical method, linear and non-linear multiple regression method (MR), and finally by a programming Multi-Layered Perception (MLP) with a Back Propagation training algorithm. The geology at the site is mostly composed of conglomerates with pebbles and boulders. The maximum settlement is estimated based on the semiempirical relations represented by several researchers. The input data set for MR and MLP models are soil characteristic [cohesion (C), internal friction angle (u), elasticity modulus (E) and unit weight (Gs)], excavation depth (Z 0 ), soil type (S t ) and PLAXIS 2D settlement prediction by the Hardening Soil model. Among all MLP and MR models, MLP models and especially model 6, the model based on E, Z, u, Gs, C and S t variables, seem to be reliable and agreeable to numerical results. The performance of MR, MLP, and optimized MLP models are evaluated by comparing statistic parameters, including coefficient correlations (R), root mean square error (RMSE), mean error (ME) and Akaike information criterion (AIC), whose values for model 6 are 0.93, 1.66, 0.89 and 13.16, respectively. Therefore, compared to other MLP and MR models, the optimized MLP model shows a relatively high level of accuracy. Additionally, model 4, the model based on E, Z, u and Gs variables, shows in MLP analysis that unit weight does not have significant effect on maximum settlement.

Scientific Quarterly Journal of Iranian Association of Engineering Geology, May 22, 2018

Theoretical and Applied Fracture Mechanics

The present work investigates the impacts of layer number, ratios of layer, brittleness of layer,... more The present work investigates the impacts of layer number, ratios of layer, brittleness of layer, layer angle, and length of notch on the shear failure of bedding rock with a welded interface, using experimental punch test and numerical modeling. The study also analyzed the acoustic emission (AE) events throughout the entire process, from initial shear stress applied to the notched bedding layer to final rock bridge failure. Rectangular samples with varying numbers of soft and hard layers were prepared. The ratio of soft gypsum thickness to total sample thickness in the one soft layered model, one hard layered model, two-layered model, three-layered model with soft interlayer, and four-layered model was 1, 0, 0.5, 0.33, and 0.5, respectively. Each model consisted of two vertical non-persistent edge notches in one direction, with notch lengths of 20, 40, and 60 mm. All layers had a horizontal configuration in the experimental test (layer angle 90◦), while angle of bedding layers varied from 0◦ to 90◦ with increments of 15◦. The considered models were investigated using punch shear tests. The results indicate that a tensile crack was initiated at the tip of the notch, propagating parallel to the shear loading axis until coalescence with the model boundary. Both peak shear strength and shear stiffness decreased as layer angles increased in models consisting of two and four layers. The mechanical properties of the three-layered model improved with increasing layer angles due to the increased presence of the hard gypsum layer in the shear failure surface. Increasing the number of layers resulted in an increased number of major AE hits, while increasing the notch length led to a drop in the number of observed AE hits. Moreover, the number of major AE hits was higher in hard ductile gypsum than in soft brittle gypsum. The failure mechanism was consistent between numerical simulation and experimental testing.

Bulletin of Engineering Geology and the Environment

Quarterly Journal of Engineering Geology and Hydrogeology

Rock Mechanics and Rock Engineering

فصلنامه علمی-پژوهشی علوم زمین, Jun 1, 2015

Geomechanics and Geoengineering, 2021

Scientific Quarterly Journal of Iranian Association of Engineering Geology, Feb 20, 2016

Geotechnical and Geological Engineering, 2021

The use of non-destructive testing methods is a well-known practice in civil engineering studies,... more The use of non-destructive testing methods is a well-known practice in civil engineering studies, Geotechnics, engineering geology, and building inspection. The Schmidt Hammer Rebound Test (SHRT) is the most prevalent of these and can be performed both in the field on rock outcrops and in the laboratory on the rock blocks and cores. During this investigation, by collecting sulfate rock blocks from the 4 under-construction, reservoir dam sites in Iran, experiments such as petrographic analysis, Uniaxial Compressive Test (UCT), and SHRT (both on rock blocks and cylindrical rock cores) were carried. Furthermore, the regression analysis of the results was performed. The investigations carried out in this study yielded several significant results. The use of ISRM criterion results in larger values of the SHRTs (N-Values) than ASTM standard criterion. In a rock consisting of gypsum-anhydrite, N-Value advances with increasing the amount of anhydrite. The presence of clay minerals in sulfate rocks can lessen the Schmidt hammer hardness. There were different correlations between the results of the SHRT and the sulfate rocks' strength properties, depending on the mineral composition of the rocks. Subsequently, because of the difficulty and time-consuming process of drying and saturating of sulfate rock samples, rock surface wetting can lead to an estimation of the saturated Uniaxial Compressive Strength (UCS) of the sulfate rocks.

1,2. Bu-Ali Sina University, Hamedan, Iran Received: 19 July 2016 Accepted: 26 July. 2017 Extende... more 1,2. Bu-Ali Sina University, Hamedan, Iran Received: 19 July 2016 Accepted: 26 July. 2017 Extended Abstract Paper pages (289-316) Introduction In regard to consumptions of oil materials by human, soil contamination causes worriness in environment and geotechnics areas in previous years, such that studying of soils lead to soil refine, soil bearing capacity and soil changing by infiltration of contamination. The rates of problems on environment are different and it depends on soil types and its structure, organic materials values, soil permeability, climate and type of contamination. In viewpoint of geotechnics, many investigations have been done on various contaminated soils that their result leads to optimum application of those as road construction and decrease of costs. In this research, with adding of different percentages of gasoil into the soil, engineering properties of contaminated soils were investigated and its effect on the erodibility of soils was studied. Regarding to t...

Journal of Applied Geophysics, 2021

Abstract Sulfate rocks are one of the problematic rocks that have always caused many problems dur... more Abstract Sulfate rocks are one of the problematic rocks that have always caused many problems during or after construction of infrastructures. In this research, by sampling of Gachsaran Formation sulfate rock layers outcrops at the four under construction, reservoir dam sites in Iran and performing lithological experiments, uniaxial compressive strength ( UCS), ultrasonic tests, the relationship between the P-wave velocity and UCS of rocks with different mineral composition and the effect of rock texture on these properties were investigated in dry and saturated conditions. The results of this research confirmed that the studied sulfate rocks had P-wave velocities ranging from 4.5 to 5.5 km / s and ranged from “high” to “very high” class in Anon's (1979) P-wave classification. In gypsum-anhydrite rocks, by increasing anhydrite content, the P-wave and the UCS of the rock increase. In rocks composed of gypsum-clay minerals and clay sized carbonates, with increasing amount of recent minerals, although the UCS increases relatively, the P-wave velocity decreases. Although this study showed that there is a correlation between the mineral composition and the P-wave velocity in sulfate rocks, but this correlation does not lead to predictive equations with sufficient reliability.

Periodica polytechnica. Civil engineering/Periodica polytechnica. Civil engineering (Online), Jul 10, 2024

Research Square (Research Square), Apr 8, 2024

This research investigates acoustic emission (AE) phenomena during shear failure of layered rock ... more This research investigates acoustic emission (AE) phenomena during shear failure of layered rock bridges under different normal stresses using experimental punch tests and numerical simulation. Firstly, particle ow code (PFC) was calibrated by UCS and Brazilian experimental test results and then the shear behavior of the numerical model was veri ed by experimental punch test outputs. Finally, acoustic phenomena during shear failure of layered rock bridges were discussed. Rectangular specimens were utilized, incorporating a combination of different layers. These layers included a pairing of soft and hard materials, as well as variations such as a two-layered model comprising hard gypsum and soft gypsum. Furthermore, three-layered models were examined, featuring a soft interlayer in one case and a hard interlayer in another. Additionally, a four-layered model was employed for the investigation. In each model, two vertical edge ssures were introduced, with ssure lengths set at 20, 40, and 60 mm. The angle between bedding layers and shear loading direction was 90°. The results indicate that cracks initiate at the notch tip and propagate vertically until they meet the upper boundary. The frequency of signi cant Acoustic hits is tied to factors like crack initiation and material properties. Increasing the number of layers in the specimen leads to more Acoustic hits. The sequence of Acoustic hits between major hits is in uenced by parameters such as bedding number and material properties. This correlation is attributed to different gypsum types on the shear surface. The ndings from numerical bedding models mirror those from physical samples.

In the present study, the effects of angle and brittleness of interlayers on the shear failure be... more In the present study, the effects of angle and brittleness of interlayers on the shear failure behavior of notched bedding rock have been scrutinized using experimental shear tests and particle flow code (PFC) simulation. Notched bedding models with dimensions of 20 cm × 24 cm × 5 cm containing soft interlayer and hard interlayer were prepared. The ratio of compressive strength to tensile strength in soft gypsum and hard gypsum are 12 and 7.8, respectively. The layer angel changed from 0° to 90° with an increment of 15°. The lengths of notches in each model are similar and were equal to 20 mm, 40 mm, and 60 mm. Models were tested by Punch shear by displacement loading rates of 0.05 mm/min. Results showed that pure tensile fracture was developed from the tip of the notch, and propagated in the direction of the shear loading axis till coalescence with the model boundary. Whereas soft brittle gypsum has less deformability in comparison to hard ductile gypsum therefore the continuity of shear displacement associated with crack growth in soft interlayer was less than that in hard interlayer. Also, soft brittle gypsum has less shear strength in comparison to hard ductile gypsum therefore the shear strength of bedding rock has maximum value when hard ductile gypsum was occupied more percentage of shear surfaces. The failure mechanism was alike in both the numerical simulation and the experimental test.

Bulletin of Engineering Geology and the Environment, Sep 7, 2014

Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by empl... more Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by employing the New Austrian Tunnelling Method in the Tehran metropolitan area, by several approaches, such as the semi-empirical method, linear and non-linear multiple regression method (MR), and finally by a programming Multi-Layered Perception (MLP) with a Back Propagation training algorithm. The geology at the site is mostly composed of conglomerates with pebbles and boulders. The maximum settlement is estimated based on the semiempirical relations represented by several researchers. The input data set for MR and MLP models are soil characteristic [cohesion (C), internal friction angle (u), elasticity modulus (E) and unit weight (Gs)], excavation depth (Z 0 ), soil type (S t ) and PLAXIS 2D settlement prediction by the Hardening Soil model. Among all MLP and MR models, MLP models and especially model 6, the model based on E, Z, u, Gs, C and S t variables, seem to be reliable and agreeable to numerical results. The performance of MR, MLP, and optimized MLP models are evaluated by comparing statistic parameters, including coefficient correlations (R), root mean square error (RMSE), mean error (ME) and Akaike information criterion (AIC), whose values for model 6 are 0.93, 1.66, 0.89 and 13.16, respectively. Therefore, compared to other MLP and MR models, the optimized MLP model shows a relatively high level of accuracy. Additionally, model 4, the model based on E, Z, u and Gs variables, shows in MLP analysis that unit weight does not have significant effect on maximum settlement.

Scientific Quarterly Journal of Iranian Association of Engineering Geology, Nov 21, 2020

To identify natural behavior of rocks under the similar moisture conditions, two saturation metho... more To identify natural behavior of rocks under the similar moisture conditions, two saturation methods of under atmospheric pressure conditions or vacuum pressure are usually used. In the method of vacuum pressure, the values of vacuum pressure Pvac as well as the time of applying this pressure Tvac are two effective parameters. In this study, the saturation method of rock, especially soluble ones such as gypsum and anhydrite, have been studied. The results of the experiments were analyzed in terms of sensitivity for four parameters of dry vacuum pressure Pvac(dry), wet vacuum pressure Pvac(wet) and the time of applying each one (Tvac(wet), Tvac(dry)). The results showed that by increasing Pvac(wet), the percentage of water absorption has been increased and the samples generally gain more than 95% of their increased weight after 4 days of applying wet vacuum and they can be practically assumed to be saturated. Applying dry vacuum Pvac(dry) before wet vacuum Pvac(wet), increases the weight of most samples after applying Pvac(wet). In case of gypsum-anhydrite rocks, the experiment showed that applying dry pressure equivalent to -0.5 atmospheres (atm) and to 5 hours (Pvac(wet) = -0.5 atm, Tvac(dry)) = 5h) propose ideal results.

Scientific Quarterly Journal of Iranian Association of Engineering Geology, Feb 19, 2013

The Extended Dynamic Cone Penetration (EDCP) test supplemented by measurement of torque (EDCP-T) ... more The Extended Dynamic Cone Penetration (EDCP) test supplemented by measurement of torque (EDCP-T) may be used to obtain a direct measurement of unit skin friction ( s f ) between the cone section and the surrounding soil. The test is performed after completion of the EDCP test. In order to perform the EDCP-T, the EDCP device is rotated after driving the rod and maximum torque is measured using a calibrated torque wrench that is connected to the top of the EDCP. The EDCP-T test results at 3 sites are presented. The results show that the unit skin friction values obtained from the EDCP-T generally correlate well with normalized blows for 30 cm penetration of the EDCP tip (NEDCP(n)). The results may be valuable for preliminary estimation of unit skin friction of the driven piles. Keywords– Penetration, driven piles, rod friction, geotechnical properties, coarse grained, fine grained

Bulletin of Engineering Geology and the Environment, 2014

Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by empl... more Here we investigate maximum settlement prediction of the Niayesh subway tunnel, excavated by employing the New Austrian Tunnelling Method in the Tehran metropolitan area, by several approaches, such as the semi-empirical method, linear and non-linear multiple regression method (MR), and finally by a programming Multi-Layered Perception (MLP) with a Back Propagation training algorithm. The geology at the site is mostly composed of conglomerates with pebbles and boulders. The maximum settlement is estimated based on the semiempirical relations represented by several researchers. The input data set for MR and MLP models are soil characteristic [cohesion (C), internal friction angle (u), elasticity modulus (E) and unit weight (Gs)], excavation depth (Z 0 ), soil type (S t ) and PLAXIS 2D settlement prediction by the Hardening Soil model. Among all MLP and MR models, MLP models and especially model 6, the model based on E, Z, u, Gs, C and S t variables, seem to be reliable and agreeable to numerical results. The performance of MR, MLP, and optimized MLP models are evaluated by comparing statistic parameters, including coefficient correlations (R), root mean square error (RMSE), mean error (ME) and Akaike information criterion (AIC), whose values for model 6 are 0.93, 1.66, 0.89 and 13.16, respectively. Therefore, compared to other MLP and MR models, the optimized MLP model shows a relatively high level of accuracy. Additionally, model 4, the model based on E, Z, u and Gs variables, shows in MLP analysis that unit weight does not have significant effect on maximum settlement.

Scientific Quarterly Journal of Iranian Association of Engineering Geology, May 22, 2018

Theoretical and Applied Fracture Mechanics

The present work investigates the impacts of layer number, ratios of layer, brittleness of layer,... more The present work investigates the impacts of layer number, ratios of layer, brittleness of layer, layer angle, and length of notch on the shear failure of bedding rock with a welded interface, using experimental punch test and numerical modeling. The study also analyzed the acoustic emission (AE) events throughout the entire process, from initial shear stress applied to the notched bedding layer to final rock bridge failure. Rectangular samples with varying numbers of soft and hard layers were prepared. The ratio of soft gypsum thickness to total sample thickness in the one soft layered model, one hard layered model, two-layered model, three-layered model with soft interlayer, and four-layered model was 1, 0, 0.5, 0.33, and 0.5, respectively. Each model consisted of two vertical non-persistent edge notches in one direction, with notch lengths of 20, 40, and 60 mm. All layers had a horizontal configuration in the experimental test (layer angle 90◦), while angle of bedding layers varied from 0◦ to 90◦ with increments of 15◦. The considered models were investigated using punch shear tests. The results indicate that a tensile crack was initiated at the tip of the notch, propagating parallel to the shear loading axis until coalescence with the model boundary. Both peak shear strength and shear stiffness decreased as layer angles increased in models consisting of two and four layers. The mechanical properties of the three-layered model improved with increasing layer angles due to the increased presence of the hard gypsum layer in the shear failure surface. Increasing the number of layers resulted in an increased number of major AE hits, while increasing the notch length led to a drop in the number of observed AE hits. Moreover, the number of major AE hits was higher in hard ductile gypsum than in soft brittle gypsum. The failure mechanism was consistent between numerical simulation and experimental testing.

Bulletin of Engineering Geology and the Environment

Quarterly Journal of Engineering Geology and Hydrogeology

Rock Mechanics and Rock Engineering

فصلنامه علمی-پژوهشی علوم زمین, Jun 1, 2015

Geomechanics and Geoengineering, 2021

Scientific Quarterly Journal of Iranian Association of Engineering Geology, Feb 20, 2016

Geotechnical and Geological Engineering, 2021

The use of non-destructive testing methods is a well-known practice in civil engineering studies,... more The use of non-destructive testing methods is a well-known practice in civil engineering studies, Geotechnics, engineering geology, and building inspection. The Schmidt Hammer Rebound Test (SHRT) is the most prevalent of these and can be performed both in the field on rock outcrops and in the laboratory on the rock blocks and cores. During this investigation, by collecting sulfate rock blocks from the 4 under-construction, reservoir dam sites in Iran, experiments such as petrographic analysis, Uniaxial Compressive Test (UCT), and SHRT (both on rock blocks and cylindrical rock cores) were carried. Furthermore, the regression analysis of the results was performed. The investigations carried out in this study yielded several significant results. The use of ISRM criterion results in larger values of the SHRTs (N-Values) than ASTM standard criterion. In a rock consisting of gypsum-anhydrite, N-Value advances with increasing the amount of anhydrite. The presence of clay minerals in sulfate rocks can lessen the Schmidt hammer hardness. There were different correlations between the results of the SHRT and the sulfate rocks' strength properties, depending on the mineral composition of the rocks. Subsequently, because of the difficulty and time-consuming process of drying and saturating of sulfate rock samples, rock surface wetting can lead to an estimation of the saturated Uniaxial Compressive Strength (UCS) of the sulfate rocks.

1,2. Bu-Ali Sina University, Hamedan, Iran Received: 19 July 2016 Accepted: 26 July. 2017 Extende... more 1,2. Bu-Ali Sina University, Hamedan, Iran Received: 19 July 2016 Accepted: 26 July. 2017 Extended Abstract Paper pages (289-316) Introduction In regard to consumptions of oil materials by human, soil contamination causes worriness in environment and geotechnics areas in previous years, such that studying of soils lead to soil refine, soil bearing capacity and soil changing by infiltration of contamination. The rates of problems on environment are different and it depends on soil types and its structure, organic materials values, soil permeability, climate and type of contamination. In viewpoint of geotechnics, many investigations have been done on various contaminated soils that their result leads to optimum application of those as road construction and decrease of costs. In this research, with adding of different percentages of gasoil into the soil, engineering properties of contaminated soils were investigated and its effect on the erodibility of soils was studied. Regarding to t...

Journal of Applied Geophysics, 2021

Abstract Sulfate rocks are one of the problematic rocks that have always caused many problems dur... more Abstract Sulfate rocks are one of the problematic rocks that have always caused many problems during or after construction of infrastructures. In this research, by sampling of Gachsaran Formation sulfate rock layers outcrops at the four under construction, reservoir dam sites in Iran and performing lithological experiments, uniaxial compressive strength ( UCS), ultrasonic tests, the relationship between the P-wave velocity and UCS of rocks with different mineral composition and the effect of rock texture on these properties were investigated in dry and saturated conditions. The results of this research confirmed that the studied sulfate rocks had P-wave velocities ranging from 4.5 to 5.5 km / s and ranged from “high” to “very high” class in Anon's (1979) P-wave classification. In gypsum-anhydrite rocks, by increasing anhydrite content, the P-wave and the UCS of the rock increase. In rocks composed of gypsum-clay minerals and clay sized carbonates, with increasing amount of recent minerals, although the UCS increases relatively, the P-wave velocity decreases. Although this study showed that there is a correlation between the mineral composition and the P-wave velocity in sulfate rocks, but this correlation does not lead to predictive equations with sufficient reliability.