Debojit Sarker

The soil–water characteristic curve (SWCC) defines the relationship between water content and matric suction in soil, which contains fundamental information needed for the hydromechanical behavior of expansive soil that generally lies within the unsaturated soil mechanics framework. Moreland clay is highly expansive soil abundant in northern Louisiana, part of Arkansas, and Oklahoma. Unsaturated soil properties for shear strength, permeability, and volume change are needed to identify expansive soil-induced stresses on pavement or railroad track due to seasonal variation of moisture content in the subgrade layers. Determination of the two critical variables obtained from the SWCC, i.e., the air-entry value (AEV) and the residual state suction, is essential for the prediction of unsaturated soil deformations. In this research, an experimental testing program was conducted on the expansive Moreland clay to investigate the soil–water retention properties by adopting the axis translation technique to control suction in the range of 0–1500 kPa. A computer program was developed to fit experimental data, and it was compared with predicted SWCC using empirical relationships. The AEV and the residual state suction, two critical variables, were obtained from the SWCC formulation of Fredlund and Xing equation. Finally, the shrinkage curve was determined to interrelate between elastic deformation and SWCC of Moreland clay.

Wastewater is a byproduct of industrial or household waste processes, and its contamination level must be determined before treatment. Discharges of liquid effluents generated by mining operations, one of the most prevalent forms of industrial waste water, pose a risk to human health and the environment. This study evaluates the physicochemical quality of industrial liquid effluent discharges from the Boukhadra mine (Algeria). Samples were collected from the washing water to identify the level of contamination of these liquid discharges and to measure physicochemical parameters such as temperature (T), hydrogen potential (pH), Electrical Conductivity (EC), Suspended Solids (SS), Chemical Oxygen Demand (COD), Biological Oxygen Demand for 5 days (BOD5), Oils and Greases (O&G), iron (Fe+2) and Kjeldahl Nitrogen (NTK). It was found that the concentration values of those effluents exceeded the maximum contamination limits specified by international industrial waste standards. A simple an...

Sometimes a pavement deflects only because of seasonal volume change of expansive soils in the pavement subgrade. Engineering practitioners expect an implementable and straightforward analysis method for a geosynthetic-reinforced pavement subjected to the swelling/shrinkage issue of expansive clayey subgrade, in an effort to find the bending moment, shear force and tension force distributions through the reinforced pavement, which are induced from the volumetric changes of subgrade soils. The virtual load method (VLM) was proposed in the past following the Timoshenko beam theory to analyze geosynthetic-reinforced pavement on expansive soils. In the VLM, the unknown virtual distributed load was obtained in the way by applying the inverse theory for the identification of material parameters of the pavement-foundation system. It was seen that the selection of the number of material parameters to obtain virtual load significantly affects the accuracy of the structural properties of the ...

The soil–water characteristic curve (SWCC) defines the relationship between water content and matric suction in soil, which contains fundamental information needed for the hydromechanical behavior of expansive soil that generally lies within the unsaturated soil mechanics framework. Moreland clay is highly expansive soil abundant in northern Louisiana, part of Arkansas, and Oklahoma. Unsaturated soil properties for shear strength, permeability, and volume change are needed to identify expansive soil-induced stresses on pavement or railroad track due to seasonal variation of moisture content in the subgrade layers. Determination of the two critical variables obtained from the SWCC, i.e., the air-entry value (AEV) and the residual state suction, is essential for the prediction of unsaturated soil deformations. In this research, an experimental testing program was conducted on the expansive Moreland clay to investigate the soil–water retention properties by adopting the axis translatio...

This paper presents a methodology to compute bending moments and shear forces, etc., in geosynthetic-reinforced pavement on expansive soils. The geosynthetic-reinforced pavement, subjected to the heave/shrinkage-induced vertical displacement caused by the volume change of expansive subgrade soils, was formulated by following the Timoshenko beam theory. The virtual load method (VLM) was developed by applying a virtual load on the pavement to make the beam deflection equivalent to the heave/shrinkage-induced vertical displacement. The unknown virtual load was expressed as a Fourier series, and the Fourier constants were determined by employing the inverse theory for the identification of material parameters. As a case study, the virtual load method was applied to investigate the effect of geosynthetics on the research road FM-2 in Texas, USA. The geosynthetics in the pavement functioned as a reinforcement to reduce the pavement damage caused by the seasonal swell and shrinkage of the expansive subgrade soils.

The study was carried out to find out a suitable numerical procedure for establishing a graphical presentation of the soil profile of a site using SPT values and grain size analysis data. MATLAB numerical tool was used for this purpose and the soil properties was estimated using established empirical correlations. A computer Software was developed where SPT values at borehole locations, percent of grain sizes, water table and GPS coordinates of the site were used as inputs, Rectangular grids in 2-D or 3-D space were created for interpolation or extrapolation of the gridded data in ‘meshgrid’ format. The output yielded intermittent SPT profile and the contour plot matrix for subsoil soil condition of a site. The output soil-profile is presented by a 3-D shaded surface plot that would be useful for preliminary selection of a project site, land use planning, zoning ordinances, pre-disaster planning, capital investment planning, Fifteen borehole data of SPT values and grain sizes along ...

Site exploration and estimation of soil attributes are key parts of a geotechnical outline process. Geotechnical engineers must focus the normal qualities and variability of soil properties. In-situ testing is turning out to be progressively essential in geotechnical engineering, as basic laboratory tests may not be solid while more advanced lab testing can be drawn out and exorbitant. One of in-situ testing examples is the Standard Penetration Test (SPT). SPT is utilized to recognize soil type and stratigraphy alongside being a relative measure of quality. SPT is a settled technique for to determine soil properties, for example, bearing capacity, liquefaction and so forth. Various types of tests are being used around the world, institutionalization is essential with a specific end goal to encourage the examination of results from diverse examinations. The nature of the test relies on upon a few elements, including the real energy conveyed to the drill rod, the dynamic properties of...

In this paper numerical analysis is carried out to identify borehole log at a particular location of a site thus producing a number of parameters which are empirically related to SPT values. The Standard Penetration Test (SPT) remains the most common site investigation tool used throughout the world. Physical properties of soil is found by correlations with values of recommended standard N60, determined in SPT tests. Janjira Ap-proach road of ongoing Padma Multipurpose Bridge Project was considered for this study to collect 15 bore-hole log along 20 km stretch. Disturbed soil sample were collected up to 19.5m depth in every 1.5m interval to perform Sieve-analysis test. Spreadsheet was used to input of over 600 data including SPT-N values, Percent Sand & Percent Fines at depths, Reduce Level & Ground Water Table at different Chainage locations. By us-ing all these data- a mathematical model was developed in MATLAB, a high-level language and interactive environment for numerical compu...

Liquefaction is one of the cardinal concern to the geotechnical engineers as well as those involved in the building and development of structural foundations. To strengthen the subsoil properties in terms of its bearing capacity, shear strength, and settlement; ground improvement techniques are often used. This paper reviews three ground improvement techniques suitable for remedial work near existing structures. Three techniques includescompaction grouting, permeation grouting, and jet grouting. Suitable method can be selected according to loading conditions, characteristics of soil, project type and cost. The factors which influence the efficacy of a particular technique are identified. From the advantages and drawbacks stated, a combination of techniques may provide the most cost-effective ground improvement solution for preventing damage to existing lives resulting from liquefaction-induced settlement and uplift. KeywordsGround Improvement, Compaction Grouting, Permeation Groutin...

The objective of this study is to recommend optimized shield design from the shielding viewpoint for installation of the Cyclotron,Cyberknife and Linear Acceleration (LINAC) facility at Bangabandhu Sheikh Mujib Medical University (BSMMU) in Dhaka, Bangladesh. The shield design for Cyclotron, Cyberknife and LINAC has been performed considering ICRP-103 (2007) recommendations for occupational and public dose limits. The optimized design parameters for Radiation Shielding Concrete (RSC) with hardened density of 2.35 gm/cm3 are: 254 cm thickness of RSC as primary barrier for LINAC on both side of the source, 198 cm and 178 cm thickness of RSC on parking side and earthen side wall for Cyclotron, a maze wall of thickness 198 cm and 122 cmRSC for Cyclotron and LINAC, 168 cm and 152 cm thickness of RSC from opposite to the maze wall, slab thickness 152 cm excluding a false ceiling of thickness 122 cm with RSC having a functional story height of 503 cm for LINAC, 122 cm and 259 cm slab thick...

Liquefaction is one of the cardinal concern to the geotechnical engineers as well as those involved in the building and development of structural foundations. To strengthen the subsoil properties in terms of its bearing capacity, shear strength, and settlement; ground improvement techniques are often used. This paper reviews three ground improvement techniques suitable for remedial work near existing structures. Three techniques includes-compaction grouting, permeation grouting, and jet grouting. Suitable method can be selected according to loading conditions, characteristics of soil, project type and cost. The factors which influence the efficacy of a particular technique are identified. From the advantages and drawbacks stated, a combination of techniques may provide the most cost-effective ground improvement solution for preventing damage to existing lives resulting from liquefaction-induced settlement and uplift.

Sometimes a pavement deflects only because of seasonal volume change of expansive soils in the pavement subgrade. Engineering practitioners expect an implementable and straightforward analysis method for a geosynthetic-reinforced pavement subjected to the swelling/shrinkage issue of expansive clayey subgrade, in an effort to find the bending moment, shear force and tension force distributions through the reinforced pavement, which are induced from the volumetric changes of subgrade soils. The virtual load method (VLM) was proposed in the past following the Timoshenko beam theory to analyze geosynthetic-reinforced pavement on expansive soils. In the VLM, the unknown virtual distributed load was obtained in the way by applying the inverse theory for the identification of material parameters of the pavement-foundation system. It was seen that the selection of the number of material parameters to obtain virtual load significantly affects the accuracy of the structural properties of the pavement and tensile properties of the geosynthetics if the linear least square method is used. In this paper, a unique numerical scheme was proposed in the hopes of solving the issue. After a forward problem was solved numerically, the Timoshenko beam deflection was taken as a start-up for the inverse problem to back analyze the load applied to the pavement. Solutions from forward/backward examples have explicitly shown the accuracy achieved related to the bending moment in the pavement and tension in the geosynthetic reinforcements. The proposed methodology can be applied for an in-depth understanding of the geosynthetic function for the mitigation of longitudinal cracks on pavements caused by heave/shrinkage of expansive soils.

In this paper, numerical analysis is carried out to identify borehole log at a particular location of
a site thus producing a number of parameters which are empirically related to SPT values. The Standard Penetration Test (SPT) remains the most common site investigation tool used throughout the world. Physical properties of soil are found by correlations with values of recommended standard N60, determined in SPT tests.
Janjira Approach road of ongoing Padma Multipurpose Bridge Project was considered for this study to collect
15 borehole log along 20 km stretch. Disturbed soil sample were collected up to 19.5m depth in every 1.5m
interval to perform Sieve-analysis test. Spreadsheet was used to input of over 600 data including SPT-N values, Percent Sand & Percent Fines at depths, Reduce Level & Ground Water Table at different Chainage locations. By using all these data- a mathematical model was developed in MATLAB, a high-level language and
interactive environment for numerical computation, visualization, and programming. Rectangular grids in
multidimensional space were created for Interpolation and/or Extrapolation for 2-D and/or 3-D gridded data
in ‘meshgrid’ format. The purposes of the study are to find vertical SPT profile & soil-profile in a particular
alignment of the site and to extract borehole log form SPT profile & soil-profile at intermittent locations of
that alignment. SPT profile is presented graphically using contour plot of matrix and soil-profile is presented
by 3-D shaded surface plots. Predicted borehole log could be useful for preliminary selection of a project site,
land use planning, zoning ordinances, pre-disaster planning, and capital investment planning. Seismic soil liquefaction was evaluated for this site in terms of the factors of safety against liquefaction (FS) along the
depths of soil profiles for different peak ground acceleration ranging 0.3g to 0.45g and earthquake magnitude
ranging 6 to 7.5 on Richter scale. Cyclic Strength Ratio (CSR) and Cyclic Resistance Ratio (CRR) was determined with 10 % probability of exceedance in 50 year using SPT-based simplified empirical procedure.
Liquefaction potential index (LPI) is evaluated at borehole locations from the obtained factors of safety (FS)
to assess the potential of liquefaction to cause damage at the surface level at the site of interest. To validate
the model, recent occurred Nepal Earthquake was taken as an example to compare the level of liquefaction
severity assessed by in-situ and predicted borehole log data.

This paper presents a methodology to compute bending moments and shear forces, etc., in geosynthetic-reinforced pavement on expansive soils. The geosynthetic-reinforced pavement, subjected to the heave/shrinkage-induced vertical displacement caused by the volume change of expansive subgrade soils, was formulated by following the Timoshenko beam theory. The virtual load method (VLM) was developed by applying a virtual load on the pavement to make the beam deflection equivalent to the heave/shrinkage-induced vertical displacement. The unknown virtual load was expressed as a Fourier series, and the Fourier constants were determined by employing the inverse theory for the identification of material parameters. As a case study, the virtual load method was applied to investigate the effect of geosynthetics on the research road FM-2 in Texas, USA. The geosynthetics in the pavement functioned as a reinforcement to reduce the pavement damage caused by the seasonal swell and shrinkage of the expansive subgrade soils.

The study was carried out to find out a suitable numerical procedure for establishing a graphical presentation of the soil profile of a site using SPT values and grain size analysis data. MATLAB numerical tool was used for this purpose and the soil properties was estimated using established empirical correlations. A computer Software was developed where SPT values at borehole locations, percent of grain sizes, water table and GPS coordinates of the site were used as inputs. Rectangular grids in 2-D or 3-D space were created for interpolation or extrapolation of the gridded data in ‘meshgrid’ format. The output yielded intermittent SPT profile and the contour plot matrix for subsoil soil condition of a site. The output soil-profile is presented by a 3-D shaded surface plot that would be useful for preliminary selection of a project site, land use planning, zoning ordinances, pre-disaster planning, capital investment planning,
Fifteen borehole data of SPT values and grain sizes along a 20 km stretch of ongoing Janjira approach road project of Padma multipurpose bridge in Madaripur district were used to verify the usability of the developed Software.  Disturbed soil sample were collected up to depths of 19.5m depth in every 1.5m interval to perform grain size analysis test. Excel spreadsheet was used where more than 500 data including SPT-N values, percent sand and  fines at depths, GPS coordinated, reduce level and ground water table. The soils at the site were predominantly alluvial deposits. All these data were used in MATLAB interactive environment for numerical computation, visualization and programming. The purposes of the study were to find SPT contour profile and soil-profile of a particular alignment of the site and to extract borehole Log form SPT profile and soil-profile of a specific location of the alignment.
Outcome of this study can be used in microzonation studies, site response analysis, calculation of bearing capacity of subsoils in the region and producing a number of parameters which are empirically related to SPT values.

Liquefaction is one of the cardinal concern to the geotechnical engineers as well as those involved in the building and development of structural foundations. To strengthen the subsoil properties in terms of its bearing capacity, shear strength, and settlement; ground improvement techniques are often used. This paper reviews three ground improvement techniques suitable for remedial work near existing structures. Three techniques includes- compaction grouting, permeation grouting, and jet grouting. Suitable method can be selected according to loading conditions, characteristics of soil, project type and cost. The factors which influence the efficacy of a particular technique are identified. From the advantages and drawbacks stated, a combination of techniques may provide the most cost-effective ground improvement solution for preventing damage to existing lives resulting from liquefaction-induced settlement and uplift.

Site  exploration  and  estimation  of  soil  attributes  are key  parts  of  a  geotechnical  outline  process.  Geotechnical engineers must focus the normal qualities and variability of soil properties.  In-situ  testing  is  turning  out  to  be  progressively essential  in  geotechnical  engineering,  as  basic  laboratory  tests may not be solid while more advanced lab testing can be drawn out  and  exorbitant.  One  of  in-situ  testing  examples  is  the Standard  Penetration  Test  (SPT).  SPT  is  utilized  to  recognize soil type and stratigraphy alongside being a relative measure of quality.  SPT  is  a  settled  technique  for  to  determine  soil properties,  for  example,  bearing  capacity,  liquefaction  and  so forth.  Various  types  of  tests  are  being  used  around  the  world, institutionalization  is essential with  a  specific  end  goal  to encourage    the    examination    of    results    from    diverse examinations.  The  nature  of  the  test  relies  on  upon  a  few elements,  including  the  real  energy  conveyed  to  the  drill  rod, the  dynamic  properties  of  the  drill  rod,  the  properties  of  the soil,  the  strategy  for  penetrating  and  the  steadiness  of  the borehole.  As  per  the  inaccessibility  of  hardware,  furthermore monetary  and  time  restrictions  in  an  undertaking  project, correlations may be used to gauge the geotechnical parameters from  the  values  obtained  from  the  in-situ  tests.  One  of  the critical  parameters  is  bearing  capacity  of  the  soil  which  could be assessed from standard penetration test. Additionally, a simple model is represented graphically in this paper to interpret SPT-N value.

The study was carried out to find out a suitable numerical procedure for establishing a graphical presentation of the soil profile of a site using SPT values and grain size analysis data. MATLAB numerical tool was used for this purpose and the soil properties was estimated using established empirical correlations. A computer Software was developed where SPT values at borehole locations, percent of grain sizes, water table and GPS coordinates of the site were used as inputs,  Rectangular grids in 2-D or 3-D space were created for interpolation or extrapolation of the gridded data in ‘meshgrid’ format. The output yielded intermittent SPT profile and the contour plot matrix for subsoil soil condition of a site. The output soil-profile is presented by a 3-D shaded surface plot that would be useful for preliminary selection of a project site, land use planning, zoning ordinances, pre-disaster planning, capital investment planning,
Fifteen borehole data of SPT values and grain sizes along a 20 km stretch of ongoing Janjira approach road project of Padma multipurpose bridge in Madaripur district were used to verify the usability of the developed Software.  Disturbed soil sample were collected up to depths of 19.5m depth in every 1.5m interval to perform grain size analysis test. Excel spreadsheet was used where more than 500 data including SPT-N values, percent sand and  fines at depths, GPS coordinated, reduce level and ground water table. The soils at the site were predominantly alluvial deposits. All these data were used in MATLAB interactive environment for numerical computation, visualization, and programming. The purposes of the study were to find SPT contour profile and soil-profile of a particular alignment of the site and to extract borehole Log form SPT profile and soil-profile of a specific location of the alignment.
Outcome of this study can be used in microzonation studies, site response analysis, calculation of bearing capacity of subsoils in the region and producing a number of parameters which are empirically related to SPT values.