Hassan Mujtaba - Academia.edu (original) (raw)

Papers by Hassan Mujtaba

Sustainability

Agro-synthetic stabilization of high-plastic clay is trending due to its vital role in sustainabl... more Agro-synthetic stabilization of high-plastic clay is trending due to its vital role in sustainable geotechnical construction and maintenance of clay subgrade. Remoulded samples of high plastic clay (C), ameliorated by optimal doses of 1.2% polyester (P) and 0.9% banana (B) at maximum dry density (γdmax) and optimum moisture content (OMC), were subjected to swell potential, unconsolidated undrained (CU) triaxial, consolidation, and California bearing ratio (CBR) tests. The outcome of this research presents that the use of an optimal clay-polyester-banana (CPB) mix enhanced the secant elastic modulus (E50), peak strength (Sp), and CBR by 2.5, 2.43, and 2.7 times, respectively; increased E50/Cc increased from 12.29 to 53.75 MPa; and lowered the swell potential by 48% and compression index (Cc) by 42.8%. It was also observed that the increase in moisture content (mc) of the optimal CPB mix from 20% (unsaturated phase) to 32% (wet phase) decreased Sp from 212 kPa to 56 kPa and E50 from 8...

Pakistan journal of science, 2014

Background: Over the course of recent years smartphone and tablet technology has evolved rapidly.... more Background: Over the course of recent years smartphone and tablet technology has evolved rapidly. Similarly, the sphere of healthcare is constantly developing and striving to embrace the newest forms of technology in order to optimise function. Many opportunities for mobile applications (i.e. 'apps') pertinent to the healthcare sector are now emerging. Objective: This study will consider whether registered pharmacists within the United Kingdom (UK) believe it appropriate to use mobile apps during the provision of healthcare within the community setting. Methods: Further to Liverpool John Moores University (LJMU) ethical approval, the 30 item questionnaire was distributed to UK registered pharmacists (n=600) practising within inner city Manchester, Liverpool and Newcastle. The questions were formatted as multiple choice, Likert scales or the open answer type. On questionnaire completion and return, data were analysed using simple frequencies, cross tabulations and nonparametric techniques in the Statistical Package for the Social Sciences (SPSS) (v18). Results: The majority of respondents (78.4% of 211 participants) confirmed that they were confident when using mobile apps on their technology platform. In general, mobile apps were perceived to be useful in facilitating patient consultations (55%) and supporting healthcare education (80%). The main barrier for mobile app use within the workplace was company policy, deemed significant in the case of regional / national chain pharmacies (p<0.001). Pharmacists alluded to the fact that whilst mobile apps demonstrate potential in modern day practise, they will have a greater impact in the future (p<0.001). Conclusion: The data indicate that although pharmacists are supportive of mobile apps in healthcare, a number of factors (i.e. risk, company policy and lack of regulation) may preclude their use in modern day pharmacy practise. Clearly, limitations of the technology must be addressed in order to maximise uptake within healthcare systems. Pharmacists suggest that as the younger generation ages, mobile apps will become a more accepted method by which to manage healthcare in the wider population.

Environmental Earth Sciences, May 1, 2023

Arabian journal for science and engineering, Jan 2, 2023

Applied Sciences

The study aims to evaluate the change in the behavior of sub-base materials being used in road pa... more The study aims to evaluate the change in the behavior of sub-base materials being used in road pavements through blending fines of different types in different amounts. Fines are added in aggregate samples as part of gradations proposed by the American Association for State and Highway Transportation Official (AASHTO). Composite samples conforming to AASHTO gradations B and C were prepared by mixing coarse aggregates in varying proportions, ranging from 0 to 15%. Laboratory tests—including aggregate quality tests (abrasion test, flakiness index and elongation Index), physical tests (particle size analysis and specific gravity), and strength test (modified Proctor, California bearing ratio, and permeability test)—were performed on the control as well as the modified samples. It was observed that the material with 0% fines yielded the highest CBR values (greater than 98%) and coefficient of permeability of 4.4 × 10−4 cm/s. However, with the increasing of the fines up to 15%, a substan...

Transportation Geotechnics

Sustainability

The present research study has been undertaken to carry out slope stability evaluation of the Jhi... more The present research study has been undertaken to carry out slope stability evaluation of the Jhika Gali landslide in Pakistan using GeoStudio. For this purpose, the site geometry of the existing slope adjacent to the slided one was measured and samples were collected from the site. The in-situ moisture content was 14% and dry unit weight was 18.63 kN/m3. Unconfined compression tests and unconsolidated-undrained (UU) triaxial tests were performed on samples reconstituted at in-situ dry unit weight, standard Proctor and modified Proctor maximum dry unit weights. The test results show that the shear strength and deformation parameters, i.e., undrained shear strength, angle of internal friction and deformation modulus decreased from 200 kPa to 90 kPa, 23° to 12° and 51 MPa to 32 MPa, respectively, with an increase in the percentage of saturation from 35% to 95% at a specific dry unit weight. The slope was also modeled in GeoStudio for limit equilibrium analysis, and slope stability ana...

Fibers

The current research has been carried out to investigate the interactive behaviour of soil-geosyn... more The current research has been carried out to investigate the interactive behaviour of soil-geosynthetic interfaces. A cost-effective vertical pullout test (VPT) apparatus was designed for this purpose. A series of laboratory direct shear tests (DSTs) and vertical pullout tests (VPT) were carried out using three types of sands and four different types of geosynthetics. All three sandy samples used in this research were classified as poorly graded sand (SP) as per the Unified Soil Classification System (USCS) with median grain size ranging between 0.39~0.2 mm. The geosynthetics used were three woven and one non-woven with a tensile force of 3.3 kN/m~103.8 kN/m. The direct shear test revealed that geometric properties of geosynthetics have an influence on interface shear resistance. Interface friction angle varies between 29.2~38.3. Vertical pullout (VPT) test results show that the pullout force is in the range of 23.9~31.4. The interface friction angle by both direct and vertical pull...

;Shear strength of soil is basic parameter in the studies like liquefaction, slope stability and ... more ;Shear strength of soil is basic parameter in the studies like liquefaction, slope stability and shallow foundation design, etc. Direct shear test is most widely used for the determination of shear strength of soil. There are various modifications in specimen size and shape for this test. According to ASTM D 3080, both square and circular shear boxes can be used for the evaluation of shear strength characteristics of soil in a direct shear test. An effort has been made in this research to evaluate basic differences in assembly of two apparatuses with circular and square shear boxes for direct shear test and to study the effects of specimen shape on the results of this test. Moreover remoulding effects on the shear strength characteristics of granular soils are also evaluated. For this purpose Ravi sand is tested in both circular and square shear box apparatuses. Similarly undisturbed and remoulded samples were tested in circular shear box. Remoulded samples were remoulded on in situ density and moisture content. Results from two apparatus shows that there is no much significant difference in angle of internal friction for the specimen tested in a direct shear test. However the angle of internal friction values obtained from circular shear box apparatus are higher (2 0 to 3 0) as compared to Square shear box. Similarly, samples which were tested in circular shear box show more horizontal resistance values and higher shear stress values. It may be due to difference in area to be sheared and shape of the specimen and also the assembly of the apparatus. Similarly, there are little differences in values of fine alluvial sand due to remolding.But the values of angle of internal friction in this research from undisturbed samples are higher and more accurate then remolded specimens. This may be, mainly due to disturbance in fabric of sand particles. So it recommended that undisturbed specimens should be used for more accurate results where possible. But the results are more sensitive to other factors like density, moisture content and type of soil then remolding and shape of specimen in direct shear test

Pakistan Journal of Engineering and Applied Sciences, 2017

The estimation of axial load carrying capacity of bored piles is a complicated problem because it... more The estimation of axial load carrying capacity of bored piles is a complicated problem because it depends upon number of factors which may include boring method, concrete quality, concreting method, experience of the staff and the ground conditions. Validation of pile design through testing of piles either test piles or working piles is considered an essential part of deep foundation design. This is recognized as being the most reliable means of dealing with the uncertainties that may rise during design and construction phase of pile foundations. In this paper, different theoretical methods have been used for the evaluation of pile capacities and then their comparison with the pile load test evaluations have been made for the project of Rathoa Haryam Bridge being constructed in Mirpur Azad Jammu & Kashmir at Mangla reservoir. The subsoil at the bridge site consists mostly of lean clay with ground water table at a shallowest depth of 0.3 m below NSL during the period of field investi...

Journal of the Geological Society of India, 2018

Improvement in engineering properties of expansive soils by mixing ground granulated blast furnac... more Improvement in engineering properties of expansive soils by mixing ground granulated blast furnace slag (GGBFS) is the main focus of this research. For this purpose two expansive soil samples were collected from DG Khan and Sialkot areas (Pakistan). Classification tests revealed that DG Khan sample belonged to fat clay (CH) while Sialkot soil was lean clay (CL) as classified by Unified Soil Classification System. GGBFS has been added in varying proportions between 0 and 55% in these soil samples to study its role in stabilizing these expansive soils. Based on the laboratory test performed on composite soil samples, it was observed that maximum dry unit weight increased up to 10 % by adding 50% GGBFS in both samples. California bearing ratio (CBR) value showed an increase from 3.2 % to 11.5% for DG Khan soil while CBR values varied from 2.4% to 10.7% for Sialkot soil by mixing 50% GGBFS. Addition of 30 % GGBFS to DG Khan soil reduced swell potential from 8 % to 2 % while in Sialkot soil, 20 % addition of GGBFS reduced swell potential from 5 % to 2 %. Unconfined compressive strength of remoulded sample cured for 28 days increased by about 35% with the addition of 30%GGBFS. The results indicated that mixing of GGBFS in the expansive soil samples have a marked increase in their engineering properties. Also, it is an affective and environmental friendly means to dispose waste of steel industry.

Arabian Journal for Science and Engineering, 2019

Compacted clay-bentonite mixtures are often used as compacted blocks and landfills in high-level ... more Compacted clay-bentonite mixtures are often used as compacted blocks and landfills in high-level radioactive waste repositories and clay liners, respectively. A better understanding of their compressibility behaviour is essential to guarantee the disposal safety. In this study, mixtures of clays and bentonite are used to investigate the compressibility and compaction behaviour. Three natural clays were selected with different physical characteristics, and clay-bentonite mixtures were prepared by mixing the bentonite content up to 50%. A series of standard compaction tests and consolidation tests were performed in the laboratory; the samples for the consolidation test were prepared at the optimum moisture contents and maximum dry unit weights. With increasing bentonite content, the liquid limit, plasticity index, optimum moisture content, initial void ratio and compression index of natural clays increase and maximum dry unit weight and yield stress decrease. It was observed that the effect of bentonite on geotechnical characteristics pronounced when bentonite content exceeded 10%. Correlations were also proposed to estimate the compression characteristics and compression curves of compacted clays using three physical parameters such as the initial void ratio, optimum moisture content and maximum dry unit weight.

KSCE Journal of Civil Engineering, 2017

This study is an attempt to evaluate relative density and friction angle of sands on the basis of... more This study is an attempt to evaluate relative density and friction angle of sands on the basis of SPT-N values. In order to develop the relationships among relative density (D r), friction angle (φ) and SPT-N value, field and laboratory test results from sixty boreholes executed in sandy deposit were used. The field tests include the SPTs conducted in the boreholes and the determination of in-situ density at various depths in the boreholes using the pitcher sampler whereas the laboratory tests include routine classification, direct shear box, maximum and minimum density and specific gravity tests. The SPT-N values were observed to vary between 4 and 100 and the in-situ bulk density of undisturbed samples as recovered through pitcher sampler are in the range of 13.24 ~ 18.44 kN/m 3. The soil samples are classified as poorly graded sand (SP), poorly graded sand with silt (SP-SM) and silty sand (SM) on the basis of Unified Soil Classification System. The values of minimum dry unit weight fall in the range of 12.22~14.95 kN/m 3 and maximum dry unit weight varies in the range of 14.64~19.17 kN/m 3 as obtained through vibratory table. Based on the test results, correlation analysis was performed to identify the parameters that affect relative density. The parameters include SPT-N value corrected for field procedures (N 6 0), relative density (D r), void ratio range (), effective overburden stresses and in-situ dry density (γ d f). Based on the results of correlation analyses, it was observed that SPT-N values alone cannot be related to D r. Therefore, multiple regression analysis was carried out using Statistical Package for the Social Sciences (SPSS) software and relation between relative density, corrected SPT-N value and effective overburden stress is being proposed. The variation between experimental and predicted values falls within ± 10% at 95% confidence interval. Validation of the proposed correlation was also performed by using an independent data set which indicated that the prediction by using the proposed correlation also falls within ± 10%. Further, comparison of the proposed correlation with other similar relationships already available in the literature was also performed. In addition to the above, correlation between φ and SPT-N 6 0 has also been proposed. It has been observed that the experimental and predicted values of friction angle fall within ± 10% with 95% confidence interval. The proposed correlations may be very useful in the field of geotechnical engineering during feasibility/preliminary design stage for rapid estimation of relative density or friction angle based on the field SPT-N 6 0 values.

… J. Engg. & Appl. Sci. Vol, 2011

The Newcastle Dilatometer (NDMT) developed by Akbar in 2001 has a distinctive feature that it loa... more The Newcastle Dilatometer (NDMT) developed by Akbar in 2001 has a distinctive feature that it loads the soil with a rigid piston in place of flexible membrane as in the Marchetti Dilatometer (MDMT). Based on the previous research works carried out using the NDMT in normally consolidated soils, it has been found that the material and dilatometer indices from the NDMT data can be used to classify the soils based on Marchetti and Crapps (1981) chart. However, in overconsolidated soils, the Marchetti and Crapps (1981) chart for soil classification sometimes shows disagreement with other methods in the prediction of soil type based on the NDMT data. This is also true with the Cone Penetrometer (CPT) data. These findings are based on extensive testing carried out in alluvial soil deposits at Kala Shah Kaku campus of the University of Engineering and Technology, Lahore. These testing comprised particle size analysis in the laboratory in conjunction with the NDMT and CPT testing in the field. This paper presents the data of penetration tests along with laboratory soil classifications and explores the possible causes of disagreement in the prediction of true soil type based on penetration tests in overconsolidated soils.

2021 International Bhurban Conference on Applied Sciences and Technologies (IBCAST), Jan 12, 2021

Recent two decades watched the shifting trend from the energy resources conventionally available ... more Recent two decades watched the shifting trend from the energy resources conventionally available to modern renewable energy resources. In our surroundings, the amount of direct current based systems has also increased. Executions of the renewable energy sources; efficient as well as effective control need to be devised. For this purpose, an accurate measurement of high and low Direct Current is required. High Direct Current sensor and the measurement system using Hall sensor is developed which is presented in this paper. The Hall Effect Sensor receives the magnetic field in a loop of fused silica-fiber around the current-carrying conductor wire and measures the path integral of the magnetic field. By using this technique, the current can be accurately measured regardless of the asymmetric magnetic field distribution. The Fiber gyro technology sensor was employed to sense signals and for processing. This fiber is completely enclosed in a flexible strip which can be installed easily. The sensor which is proposed in the work has accuracy within 0.1% over a wide range of currents and temperature. It is determined with experimental results that the High-Voltage DC sensors and the measurement system proposed in this research are working correctly with acceptable accuracy.

Geotechnical and Geological Engineering

KSCE Journal of Civil Engineering

In this paper, Desirability Optimization Methodology (DOM) is employed to achieve optimum sand be... more In this paper, Desirability Optimization Methodology (DOM) is employed to achieve optimum sand bentonite mixture (SBM) based on multiple antagonist macro-geotechnical responses of the compacted SBM prepared using poorly graded sand with the mean grain size around 0.2 mm and bentonite with plasticity index around 157% for the stable engineered barriers (EBs). For this purpose, varying mix designs of SBM compacted at compaction energy of 2,700 kN-m/m 3 are initially tested to determine their mechanical properties, volumetric-change behavior, and hydraulic conductivity. The unconfined compressive strength, cohesion, angle of internal fiction, swell pressure, compression index, and hydraulic conductivity are taken as the geotechnical design parameters for the SBM. Mathematical models are developed and statistically validated for these design parameters using sand content (SC) and bentonite content (BC) as the predictors. In addition, models are also developed to predict compression curves for compacted SBMs. Moreover, microstructural evaluation is conducted through scanning electron microscope (SEM) analysis to determine the SBM having a desirable microstructure for stable EB. It is observed that a major shift in the microstructure from medium pores to micro-pores occurs for the BC between 20% and 30%. Afterward, optimization of SBM is carried out by integrating developed models for the geotechnical design parameters in a desirability function (D) algorithm, which is subsequently simulated by setting maximization of strength and minimization of swell pressure, compressibility and hydraulic conductivity of compacted SBM as the goals. A reasonably high D-value is achieved for the SBMs having SC:BC in a range of 74:26 to 78:22 with the highest at 75.63:24.37 against the set goals. This study manifests an effective and pragmatic strategy for designing the SBM for a stable EB considering its antagonist hydraulic, volumetric change, and mechanical responses. Sand-bentonite mixtures Macro-characteristics evaluation Microstructure Correlation models Optimized mix design CORRESPONDENCE Zia ur Rehman

Sustainability

Agro-synthetic stabilization of high-plastic clay is trending due to its vital role in sustainabl... more Agro-synthetic stabilization of high-plastic clay is trending due to its vital role in sustainable geotechnical construction and maintenance of clay subgrade. Remoulded samples of high plastic clay (C), ameliorated by optimal doses of 1.2% polyester (P) and 0.9% banana (B) at maximum dry density (γdmax) and optimum moisture content (OMC), were subjected to swell potential, unconsolidated undrained (CU) triaxial, consolidation, and California bearing ratio (CBR) tests. The outcome of this research presents that the use of an optimal clay-polyester-banana (CPB) mix enhanced the secant elastic modulus (E50), peak strength (Sp), and CBR by 2.5, 2.43, and 2.7 times, respectively; increased E50/Cc increased from 12.29 to 53.75 MPa; and lowered the swell potential by 48% and compression index (Cc) by 42.8%. It was also observed that the increase in moisture content (mc) of the optimal CPB mix from 20% (unsaturated phase) to 32% (wet phase) decreased Sp from 212 kPa to 56 kPa and E50 from 8...

Pakistan journal of science, 2014

Background: Over the course of recent years smartphone and tablet technology has evolved rapidly.... more Background: Over the course of recent years smartphone and tablet technology has evolved rapidly. Similarly, the sphere of healthcare is constantly developing and striving to embrace the newest forms of technology in order to optimise function. Many opportunities for mobile applications (i.e. 'apps') pertinent to the healthcare sector are now emerging. Objective: This study will consider whether registered pharmacists within the United Kingdom (UK) believe it appropriate to use mobile apps during the provision of healthcare within the community setting. Methods: Further to Liverpool John Moores University (LJMU) ethical approval, the 30 item questionnaire was distributed to UK registered pharmacists (n=600) practising within inner city Manchester, Liverpool and Newcastle. The questions were formatted as multiple choice, Likert scales or the open answer type. On questionnaire completion and return, data were analysed using simple frequencies, cross tabulations and nonparametric techniques in the Statistical Package for the Social Sciences (SPSS) (v18). Results: The majority of respondents (78.4% of 211 participants) confirmed that they were confident when using mobile apps on their technology platform. In general, mobile apps were perceived to be useful in facilitating patient consultations (55%) and supporting healthcare education (80%). The main barrier for mobile app use within the workplace was company policy, deemed significant in the case of regional / national chain pharmacies (p<0.001). Pharmacists alluded to the fact that whilst mobile apps demonstrate potential in modern day practise, they will have a greater impact in the future (p<0.001). Conclusion: The data indicate that although pharmacists are supportive of mobile apps in healthcare, a number of factors (i.e. risk, company policy and lack of regulation) may preclude their use in modern day pharmacy practise. Clearly, limitations of the technology must be addressed in order to maximise uptake within healthcare systems. Pharmacists suggest that as the younger generation ages, mobile apps will become a more accepted method by which to manage healthcare in the wider population.

Environmental Earth Sciences, May 1, 2023

Arabian journal for science and engineering, Jan 2, 2023

Applied Sciences

The study aims to evaluate the change in the behavior of sub-base materials being used in road pa... more The study aims to evaluate the change in the behavior of sub-base materials being used in road pavements through blending fines of different types in different amounts. Fines are added in aggregate samples as part of gradations proposed by the American Association for State and Highway Transportation Official (AASHTO). Composite samples conforming to AASHTO gradations B and C were prepared by mixing coarse aggregates in varying proportions, ranging from 0 to 15%. Laboratory tests—including aggregate quality tests (abrasion test, flakiness index and elongation Index), physical tests (particle size analysis and specific gravity), and strength test (modified Proctor, California bearing ratio, and permeability test)—were performed on the control as well as the modified samples. It was observed that the material with 0% fines yielded the highest CBR values (greater than 98%) and coefficient of permeability of 4.4 × 10−4 cm/s. However, with the increasing of the fines up to 15%, a substan...

Transportation Geotechnics

Sustainability

The present research study has been undertaken to carry out slope stability evaluation of the Jhi... more The present research study has been undertaken to carry out slope stability evaluation of the Jhika Gali landslide in Pakistan using GeoStudio. For this purpose, the site geometry of the existing slope adjacent to the slided one was measured and samples were collected from the site. The in-situ moisture content was 14% and dry unit weight was 18.63 kN/m3. Unconfined compression tests and unconsolidated-undrained (UU) triaxial tests were performed on samples reconstituted at in-situ dry unit weight, standard Proctor and modified Proctor maximum dry unit weights. The test results show that the shear strength and deformation parameters, i.e., undrained shear strength, angle of internal friction and deformation modulus decreased from 200 kPa to 90 kPa, 23° to 12° and 51 MPa to 32 MPa, respectively, with an increase in the percentage of saturation from 35% to 95% at a specific dry unit weight. The slope was also modeled in GeoStudio for limit equilibrium analysis, and slope stability ana...

Fibers

The current research has been carried out to investigate the interactive behaviour of soil-geosyn... more The current research has been carried out to investigate the interactive behaviour of soil-geosynthetic interfaces. A cost-effective vertical pullout test (VPT) apparatus was designed for this purpose. A series of laboratory direct shear tests (DSTs) and vertical pullout tests (VPT) were carried out using three types of sands and four different types of geosynthetics. All three sandy samples used in this research were classified as poorly graded sand (SP) as per the Unified Soil Classification System (USCS) with median grain size ranging between 0.39~0.2 mm. The geosynthetics used were three woven and one non-woven with a tensile force of 3.3 kN/m~103.8 kN/m. The direct shear test revealed that geometric properties of geosynthetics have an influence on interface shear resistance. Interface friction angle varies between 29.2~38.3. Vertical pullout (VPT) test results show that the pullout force is in the range of 23.9~31.4. The interface friction angle by both direct and vertical pull...

;Shear strength of soil is basic parameter in the studies like liquefaction, slope stability and ... more ;Shear strength of soil is basic parameter in the studies like liquefaction, slope stability and shallow foundation design, etc. Direct shear test is most widely used for the determination of shear strength of soil. There are various modifications in specimen size and shape for this test. According to ASTM D 3080, both square and circular shear boxes can be used for the evaluation of shear strength characteristics of soil in a direct shear test. An effort has been made in this research to evaluate basic differences in assembly of two apparatuses with circular and square shear boxes for direct shear test and to study the effects of specimen shape on the results of this test. Moreover remoulding effects on the shear strength characteristics of granular soils are also evaluated. For this purpose Ravi sand is tested in both circular and square shear box apparatuses. Similarly undisturbed and remoulded samples were tested in circular shear box. Remoulded samples were remoulded on in situ density and moisture content. Results from two apparatus shows that there is no much significant difference in angle of internal friction for the specimen tested in a direct shear test. However the angle of internal friction values obtained from circular shear box apparatus are higher (2 0 to 3 0) as compared to Square shear box. Similarly, samples which were tested in circular shear box show more horizontal resistance values and higher shear stress values. It may be due to difference in area to be sheared and shape of the specimen and also the assembly of the apparatus. Similarly, there are little differences in values of fine alluvial sand due to remolding.But the values of angle of internal friction in this research from undisturbed samples are higher and more accurate then remolded specimens. This may be, mainly due to disturbance in fabric of sand particles. So it recommended that undisturbed specimens should be used for more accurate results where possible. But the results are more sensitive to other factors like density, moisture content and type of soil then remolding and shape of specimen in direct shear test

Pakistan Journal of Engineering and Applied Sciences, 2017

The estimation of axial load carrying capacity of bored piles is a complicated problem because it... more The estimation of axial load carrying capacity of bored piles is a complicated problem because it depends upon number of factors which may include boring method, concrete quality, concreting method, experience of the staff and the ground conditions. Validation of pile design through testing of piles either test piles or working piles is considered an essential part of deep foundation design. This is recognized as being the most reliable means of dealing with the uncertainties that may rise during design and construction phase of pile foundations. In this paper, different theoretical methods have been used for the evaluation of pile capacities and then their comparison with the pile load test evaluations have been made for the project of Rathoa Haryam Bridge being constructed in Mirpur Azad Jammu & Kashmir at Mangla reservoir. The subsoil at the bridge site consists mostly of lean clay with ground water table at a shallowest depth of 0.3 m below NSL during the period of field investi...

Journal of the Geological Society of India, 2018

Improvement in engineering properties of expansive soils by mixing ground granulated blast furnac... more Improvement in engineering properties of expansive soils by mixing ground granulated blast furnace slag (GGBFS) is the main focus of this research. For this purpose two expansive soil samples were collected from DG Khan and Sialkot areas (Pakistan). Classification tests revealed that DG Khan sample belonged to fat clay (CH) while Sialkot soil was lean clay (CL) as classified by Unified Soil Classification System. GGBFS has been added in varying proportions between 0 and 55% in these soil samples to study its role in stabilizing these expansive soils. Based on the laboratory test performed on composite soil samples, it was observed that maximum dry unit weight increased up to 10 % by adding 50% GGBFS in both samples. California bearing ratio (CBR) value showed an increase from 3.2 % to 11.5% for DG Khan soil while CBR values varied from 2.4% to 10.7% for Sialkot soil by mixing 50% GGBFS. Addition of 30 % GGBFS to DG Khan soil reduced swell potential from 8 % to 2 % while in Sialkot soil, 20 % addition of GGBFS reduced swell potential from 5 % to 2 %. Unconfined compressive strength of remoulded sample cured for 28 days increased by about 35% with the addition of 30%GGBFS. The results indicated that mixing of GGBFS in the expansive soil samples have a marked increase in their engineering properties. Also, it is an affective and environmental friendly means to dispose waste of steel industry.

Arabian Journal for Science and Engineering, 2019

Compacted clay-bentonite mixtures are often used as compacted blocks and landfills in high-level ... more Compacted clay-bentonite mixtures are often used as compacted blocks and landfills in high-level radioactive waste repositories and clay liners, respectively. A better understanding of their compressibility behaviour is essential to guarantee the disposal safety. In this study, mixtures of clays and bentonite are used to investigate the compressibility and compaction behaviour. Three natural clays were selected with different physical characteristics, and clay-bentonite mixtures were prepared by mixing the bentonite content up to 50%. A series of standard compaction tests and consolidation tests were performed in the laboratory; the samples for the consolidation test were prepared at the optimum moisture contents and maximum dry unit weights. With increasing bentonite content, the liquid limit, plasticity index, optimum moisture content, initial void ratio and compression index of natural clays increase and maximum dry unit weight and yield stress decrease. It was observed that the effect of bentonite on geotechnical characteristics pronounced when bentonite content exceeded 10%. Correlations were also proposed to estimate the compression characteristics and compression curves of compacted clays using three physical parameters such as the initial void ratio, optimum moisture content and maximum dry unit weight.

KSCE Journal of Civil Engineering, 2017

This study is an attempt to evaluate relative density and friction angle of sands on the basis of... more This study is an attempt to evaluate relative density and friction angle of sands on the basis of SPT-N values. In order to develop the relationships among relative density (D r), friction angle (φ) and SPT-N value, field and laboratory test results from sixty boreholes executed in sandy deposit were used. The field tests include the SPTs conducted in the boreholes and the determination of in-situ density at various depths in the boreholes using the pitcher sampler whereas the laboratory tests include routine classification, direct shear box, maximum and minimum density and specific gravity tests. The SPT-N values were observed to vary between 4 and 100 and the in-situ bulk density of undisturbed samples as recovered through pitcher sampler are in the range of 13.24 ~ 18.44 kN/m 3. The soil samples are classified as poorly graded sand (SP), poorly graded sand with silt (SP-SM) and silty sand (SM) on the basis of Unified Soil Classification System. The values of minimum dry unit weight fall in the range of 12.22~14.95 kN/m 3 and maximum dry unit weight varies in the range of 14.64~19.17 kN/m 3 as obtained through vibratory table. Based on the test results, correlation analysis was performed to identify the parameters that affect relative density. The parameters include SPT-N value corrected for field procedures (N 6 0), relative density (D r), void ratio range (), effective overburden stresses and in-situ dry density (γ d f). Based on the results of correlation analyses, it was observed that SPT-N values alone cannot be related to D r. Therefore, multiple regression analysis was carried out using Statistical Package for the Social Sciences (SPSS) software and relation between relative density, corrected SPT-N value and effective overburden stress is being proposed. The variation between experimental and predicted values falls within ± 10% at 95% confidence interval. Validation of the proposed correlation was also performed by using an independent data set which indicated that the prediction by using the proposed correlation also falls within ± 10%. Further, comparison of the proposed correlation with other similar relationships already available in the literature was also performed. In addition to the above, correlation between φ and SPT-N 6 0 has also been proposed. It has been observed that the experimental and predicted values of friction angle fall within ± 10% with 95% confidence interval. The proposed correlations may be very useful in the field of geotechnical engineering during feasibility/preliminary design stage for rapid estimation of relative density or friction angle based on the field SPT-N 6 0 values.

… J. Engg. & Appl. Sci. Vol, 2011

The Newcastle Dilatometer (NDMT) developed by Akbar in 2001 has a distinctive feature that it loa... more The Newcastle Dilatometer (NDMT) developed by Akbar in 2001 has a distinctive feature that it loads the soil with a rigid piston in place of flexible membrane as in the Marchetti Dilatometer (MDMT). Based on the previous research works carried out using the NDMT in normally consolidated soils, it has been found that the material and dilatometer indices from the NDMT data can be used to classify the soils based on Marchetti and Crapps (1981) chart. However, in overconsolidated soils, the Marchetti and Crapps (1981) chart for soil classification sometimes shows disagreement with other methods in the prediction of soil type based on the NDMT data. This is also true with the Cone Penetrometer (CPT) data. These findings are based on extensive testing carried out in alluvial soil deposits at Kala Shah Kaku campus of the University of Engineering and Technology, Lahore. These testing comprised particle size analysis in the laboratory in conjunction with the NDMT and CPT testing in the field. This paper presents the data of penetration tests along with laboratory soil classifications and explores the possible causes of disagreement in the prediction of true soil type based on penetration tests in overconsolidated soils.

2021 International Bhurban Conference on Applied Sciences and Technologies (IBCAST), Jan 12, 2021

Recent two decades watched the shifting trend from the energy resources conventionally available ... more Recent two decades watched the shifting trend from the energy resources conventionally available to modern renewable energy resources. In our surroundings, the amount of direct current based systems has also increased. Executions of the renewable energy sources; efficient as well as effective control need to be devised. For this purpose, an accurate measurement of high and low Direct Current is required. High Direct Current sensor and the measurement system using Hall sensor is developed which is presented in this paper. The Hall Effect Sensor receives the magnetic field in a loop of fused silica-fiber around the current-carrying conductor wire and measures the path integral of the magnetic field. By using this technique, the current can be accurately measured regardless of the asymmetric magnetic field distribution. The Fiber gyro technology sensor was employed to sense signals and for processing. This fiber is completely enclosed in a flexible strip which can be installed easily. The sensor which is proposed in the work has accuracy within 0.1% over a wide range of currents and temperature. It is determined with experimental results that the High-Voltage DC sensors and the measurement system proposed in this research are working correctly with acceptable accuracy.

Geotechnical and Geological Engineering

KSCE Journal of Civil Engineering

In this paper, Desirability Optimization Methodology (DOM) is employed to achieve optimum sand be... more In this paper, Desirability Optimization Methodology (DOM) is employed to achieve optimum sand bentonite mixture (SBM) based on multiple antagonist macro-geotechnical responses of the compacted SBM prepared using poorly graded sand with the mean grain size around 0.2 mm and bentonite with plasticity index around 157% for the stable engineered barriers (EBs). For this purpose, varying mix designs of SBM compacted at compaction energy of 2,700 kN-m/m 3 are initially tested to determine their mechanical properties, volumetric-change behavior, and hydraulic conductivity. The unconfined compressive strength, cohesion, angle of internal fiction, swell pressure, compression index, and hydraulic conductivity are taken as the geotechnical design parameters for the SBM. Mathematical models are developed and statistically validated for these design parameters using sand content (SC) and bentonite content (BC) as the predictors. In addition, models are also developed to predict compression curves for compacted SBMs. Moreover, microstructural evaluation is conducted through scanning electron microscope (SEM) analysis to determine the SBM having a desirable microstructure for stable EB. It is observed that a major shift in the microstructure from medium pores to micro-pores occurs for the BC between 20% and 30%. Afterward, optimization of SBM is carried out by integrating developed models for the geotechnical design parameters in a desirability function (D) algorithm, which is subsequently simulated by setting maximization of strength and minimization of swell pressure, compressibility and hydraulic conductivity of compacted SBM as the goals. A reasonably high D-value is achieved for the SBMs having SC:BC in a range of 74:26 to 78:22 with the highest at 75.63:24.37 against the set goals. This study manifests an effective and pragmatic strategy for designing the SBM for a stable EB considering its antagonist hydraulic, volumetric change, and mechanical responses. Sand-bentonite mixtures Macro-characteristics evaluation Microstructure Correlation models Optimized mix design CORRESPONDENCE Zia ur Rehman