The main objective of the current work is to examine the dynamic axial response of three pile gro... more The main objective of the current work is to examine the dynamic axial response of three pile group under machine-based harmonic loads. Field tests are carried out under axial harmonic excitations on a group pile with a pile length of 300 cm and an diameter of 11.4 cm in order to accomplish this objective. For various eccentric moments, the frequency versus amplitude responses of the group pile are measured. The field test results of the soil-pile system show non-linear behaviour as their resonant frequencies decrease and their resonant amplitudes disproportionally increase with eccentric forces. The inverse methodology proposed by Novak (1971) is used for the theoretical study. With this methodology, the changes in stiffness, damping, and effective mass of the piles under various eccentric moments are quantified by analyzing the frequency-amplitude response curves of field results. The theoretically back-calculated soil-pile system response curves are compared with the field results, and it is observed that the analytically predicted responses closely match the field responses. It is also found that the values of estimated damping of the pile group increased, while effective mass and average stiffness values decreased with an increase in eccentric moments. Keywords Axial harmonic excitations • Soil-pile system • Field tests •
Deterministic seismic hazard assessment based study using various attenuation relationships has b... more Deterministic seismic hazard assessment based study using various attenuation relationships has been taken up to find out the peak ground acceleration (PGA) for Sitamarhi region situated near the Bihar Nepal border. Seismicity data were collected from Indian Meteorological Department, New Delhi and Seismotectonic Atlas of India and 38 seismotectonic sources were identified in the region. The results show that the Main Central Thrust and West Patna subsurface fault are the two main faults, which contribute to maximum PGA values for Sitamarhi region. The calculated PGA values are in confirmation with the observed values from other sources.
In the present paper, multivariate adaptive regression splines (MARS) method is used to carry out... more In the present paper, multivariate adaptive regression splines (MARS) method is used to carry out reliability analysis of Durgawati earthen dam. The steady and transient state seepage is considered while calculating reliability index \(\left( \beta \right)\). The earthen dam is an important water retaining structure and serves the catchment area of Durgawati River in Bihar, India. The factor of safety (FOS) of the earthen dam against slope failure under steady and transient state is performed using GeoStudio-07 software. In order to account for the variability of material parameters over the body of the dam, a data set of material parameters [i.e., cohesion (\(c\)), angle of internal friction \(\left( \varphi \right)\) and soil unit weight (\(\gamma\))] are prepared, and MARS is used to calculate reliability index \(\left( \beta \right)\) for different realizations over the dam geometry. The reliability index \(\left( \beta \right)\) thus estimated shows that the dam is stable and safe from slope failure point of view under different seepage loadings.
The main objective of the current investigation is to study the dynamic behaviour of a 3-pile gro... more The main objective of the current investigation is to study the dynamic behaviour of a 3-pile group with two different arrangements of pile setups under coupled (horizontal and rocking) excitations. To accomplish this objective, machine-induced field excitation tests are conducted on small-scale hollow steel piles. The 3-pile group is driven into the ground in a triangular arrangement with 3d spacing. Two different soil-pile setups, i.e., Pile Group-I and Pile Group-II, are created based on dynamic force directions. In the case of Pile Group-I, the forces are applied to the direction of the median of the triangle, and for Pile Group-II, the forces are applied to other directional loads. From the test results, it is found that the resonant peaks of horizontal and rocking amplitudes for Pile Group-I are lower than Pile Group-II. In the case of resonant frequencies, the values of Pile Group-I are observed to be the same or a little bit higher as compared to Pile Group-II. It is found that the dynamic soil-pile-soil interaction effect is more prominent for Pile Group-II than for Pile Group-I. For numerical investigation, the continuum approach method is utilised with the inclusion of a dynamic group interaction factor to predict the dynamic coupled responses in terms of frequency and amplitude for these two soil-pile setups. To understand the behaviour of pile groups, boundary zone parameters and variations of impedance parameters (stiffness and damping) with operating frequencies are also measured using this theoretical approach.
Geotechnical and Geological Engineering, Dec 13, 2019
The solution of slope stability problems requires determination of critical failure surface and a... more The solution of slope stability problems requires determination of critical failure surface and associated optimum/minimum factor of safety (FOS) value. Investigation of critical failure surface in any soil slope can be posed as a constrained global optimization problem. In this article, a simplified technique of generation of segmented non-circular failure surface is proposed. Unified particle swarm optimization (UPSO) method is utilized to search for the critical failure surface and associated minimum FOS of the slope. Limit equilibrium technique-based Morgenstern–Price method is used to evaluate the FOS value of the potential failure mass which satisfy both force as well as moment equilibrium. To demonstrate the performance of UPSO and its competence in yielding critical failure surface along with minimum FOS value, three benchmark problems with differing complexities are chosen from existing literatures. The results obtained are compared and are found to be in accord with the published literatures. The performance of UPSO as a solution algorithm for slope problems are established through convergence studies of various related parameters.
Geotechnical and Geological Engineering, May 17, 2020
In this study, seepage through the body of an earthen embankment for construction of railway line... more In this study, seepage through the body of an earthen embankment for construction of railway lines in Mokama in Bihar is estimated using finite element method. Seepage of water through the body of earthen embankment adversely affects its stability. In order to check the reliability of the constructed railway embankment stretching for a long distance, Random Finite Element Method (RFEM) originally developed by is used. The influence of variability in spatially distributed hydraulic conductivity/permeability field of the embankment is investigated by carrying out seepage analysis. Local Averaging Subdivision (LAS) technique is used to build the random field of hydraulic conductivity of soil domain under consideration. Afterwards, Monte Carlo simulation is performed for 1000 such random fields. The mean of total flow rate m Q ð Þ, mean of logarithmic of total flow rate m ln Q ð Þ and variance of logarithmic of total flow rate s 2 ln Q from seepage analyses for 1000 realizations of random field are reported. The results show that as the correlation length decreases, the output parameters m Q , m ln Q and s 2 ln Q follow a decreasing trend and vice versa. These variations are studied for the embankment with and without drain. The effect of drain on the mean hydraulic conductivity and hydraulic gradient standard deviation of the embankment are investigated in which the embankment with drains is found safer than embankment without drain.
Geotechnical and Geological Engineering, Oct 18, 2019
The districts of Madhubani and Supaul lie near Bihar-Nepal border along foothills of Himalaya. Di... more The districts of Madhubani and Supaul lie near Bihar-Nepal border along foothills of Himalaya. Different attenuation relationships applicable for the Himalayan region have been used to estimate the sitespecific Peak Ground Acceleration (PGA) for the Madhubani and Supaul region on the basis of Deterministic Seismic Hazard Assessment (DSHA) study. Seismicity data have been collected from IMD, New Delhi and forty seismotectonic sources were recognized in the region from Seismotectonic Atlas of India (GSI in Seismotectonic atlas of India and its environs, Geological Survey of India, Kolkata, 2000). Hypocentral distances have been measured using ArcGIS software. Maximum Peak ground acceleration value is found to occur for Main Central Thrust fault for both these districts.
This article presents results of slope analyses employing a simple technique of generating segmen... more This article presents results of slope analyses employing a simple technique of generating segmented non-circular failure surfaces. The formulation of slope analysis is performed as an optimization problem with four constrained control variables characterizing the failure surface. In this study, different variants of particle swarm optimization (PSO) methods such as inertia weight equipped and contemporary standard PSO (CS-PSO) are utilized to obtain optimum control variables and associated critical failure surface. The factor of safety of the slope or the objective function of the constrained optimization problem is determined by Morgenstern-Price method. To explore the competence of proposed method with different PSO models, three benchmark problems are analysed for different maximum number of function evaluations such as 1000, 2500 and 5000. A series of sensitivity analyses are performed for various parameters such as swarm size with maximum iteration count of 100. The swarm diversity behaviour is also studied in relation with converged or promising global optimum solution. It is found that contemporary standard PSO (CS-PSO) with or without velocity clamping maintains better swarm diversity and preserves the balance between swarm "exploration" and "exploitation" efficiently. Velocity clamping and positional clamping are recommended as they prevent the solution/control variable from overflying the swarm best position.
Beni-Suef University Journal of Basic and Applied Sciences
Background It is a well-known fact that the safety of slopes majorly depends on several factors s... more Background It is a well-known fact that the safety of slopes majorly depends on several factors such as geometry, soil properties. The safety factor might change significantly depending on the soil type and the slope’s shape. The knowledge of the nature of the change in the safety factor due to the change in the slope’s height and angle is essential for implementing an effective strategy of increasing the safety factor for any slope stability problem. The influence of geometric shapes on the stability of the slope needs to be properly investigated through three-dimensional slope stability analysis, as the three-dimensional analysis is suitable for all slopes, even those which invalidate the plane-strain conditions. Results To calculate the three-dimensional safety factor, multiple analyses of three homogenous soil slopes with different soil properties were conducted by varying slope height, angle, and combinations. Each slope's height and angle were recorded to identify the type...
In the past, numerous stratovolcanoes worldwide witnessed catastrophic flank collapses. One of th... more In the past, numerous stratovolcanoes worldwide witnessed catastrophic flank collapses. One of the greatest risks associated with stratovolcanoes is a massive rock failure. On 18 May 1980, we witnessed a rock slope failure due to a volcano eruption, and a 2185.60 m high rock slope of Mount St. Helens was collapsed. Thus, from the serviceability perspective, this work presents an effective computational technique to perform probabilistic analyses of Mount St. Helens situated in Washington, USA. Using the first-order second-moment method, probability theory and statistics were employed to map the uncertainties in rock parameters. Initially, Scoops3D was used to perform slope stability analysis followed by probabilistic evaluation using a hybrid computational model of artificial neural network (ANN) and firefly algorithm (FF), i.e., ANN-FF. The performance of the ANN-FF model was examined and compared with that of conventional ANN and other hybrid ANNs built using seven additional meta...
The main objective of the current investigation is to study the dynamic behaviour of a 3-pile gro... more The main objective of the current investigation is to study the dynamic behaviour of a 3-pile group with two different arrangements of pile setups under coupled (horizontal and rocking) excitations. To accomplish this objective, machine-induced field excitation tests are conducted on small-scale hollow steel piles. The 3-pile group is driven into the ground in a triangular arrangement with 3d spacing. Two different soil-pile setups, i.e., Pile Group-I and Pile Group-II, are created based on dynamic force directions. In the case of Pile Group-I, the forces are applied to the direction of the median of the triangle, and for Pile Group-II, the forces are applied to other directional loads. From the test results, it is found that the resonant peaks of horizontal and rocking amplitudes for Pile Group-I are lower than Pile Group-II. In the case of resonant frequencies, the values of Pile Group-I are observed to be the same or a little bit higher as compared to Pile Group-II. It is found t...
The main objective of the current work is to examine the dynamic axial response of three pile gro... more The main objective of the current work is to examine the dynamic axial response of three pile group under machine-based harmonic loads. Field tests are carried out under axial harmonic excitations on a group pile with a pile length of 300 cm and an diameter of 11.4 cm in order to accomplish this objective. For various eccentric moments, the frequency versus amplitude responses of the group pile are measured. The field test results of the soil-pile system show non-linear behaviour as their resonant frequencies decrease and their resonant amplitudes disproportionally increase with eccentric forces. The inverse methodology proposed by Novak (1971) is used for the theoretical study. With this methodology, the changes in stiffness, damping, and effective mass of the piles under various eccentric moments are quantified by analyzing the frequency-amplitude response curves of field results. The theoretically back-calculated soil-pile system response curves are compared with the field results, and it is observed that the analytically predicted responses closely match the field responses. It is also found that the values of estimated damping of the pile group increased, while effective mass and average stiffness values decreased with an increase in eccentric moments. Keywords Axial harmonic excitations • Soil-pile system • Field tests •
Deterministic seismic hazard assessment based study using various attenuation relationships has b... more Deterministic seismic hazard assessment based study using various attenuation relationships has been taken up to find out the peak ground acceleration (PGA) for Sitamarhi region situated near the Bihar Nepal border. Seismicity data were collected from Indian Meteorological Department, New Delhi and Seismotectonic Atlas of India and 38 seismotectonic sources were identified in the region. The results show that the Main Central Thrust and West Patna subsurface fault are the two main faults, which contribute to maximum PGA values for Sitamarhi region. The calculated PGA values are in confirmation with the observed values from other sources.
In the present paper, multivariate adaptive regression splines (MARS) method is used to carry out... more In the present paper, multivariate adaptive regression splines (MARS) method is used to carry out reliability analysis of Durgawati earthen dam. The steady and transient state seepage is considered while calculating reliability index \(\left( \beta \right)\). The earthen dam is an important water retaining structure and serves the catchment area of Durgawati River in Bihar, India. The factor of safety (FOS) of the earthen dam against slope failure under steady and transient state is performed using GeoStudio-07 software. In order to account for the variability of material parameters over the body of the dam, a data set of material parameters [i.e., cohesion (\(c\)), angle of internal friction \(\left( \varphi \right)\) and soil unit weight (\(\gamma\))] are prepared, and MARS is used to calculate reliability index \(\left( \beta \right)\) for different realizations over the dam geometry. The reliability index \(\left( \beta \right)\) thus estimated shows that the dam is stable and safe from slope failure point of view under different seepage loadings.
The main objective of the current investigation is to study the dynamic behaviour of a 3-pile gro... more The main objective of the current investigation is to study the dynamic behaviour of a 3-pile group with two different arrangements of pile setups under coupled (horizontal and rocking) excitations. To accomplish this objective, machine-induced field excitation tests are conducted on small-scale hollow steel piles. The 3-pile group is driven into the ground in a triangular arrangement with 3d spacing. Two different soil-pile setups, i.e., Pile Group-I and Pile Group-II, are created based on dynamic force directions. In the case of Pile Group-I, the forces are applied to the direction of the median of the triangle, and for Pile Group-II, the forces are applied to other directional loads. From the test results, it is found that the resonant peaks of horizontal and rocking amplitudes for Pile Group-I are lower than Pile Group-II. In the case of resonant frequencies, the values of Pile Group-I are observed to be the same or a little bit higher as compared to Pile Group-II. It is found that the dynamic soil-pile-soil interaction effect is more prominent for Pile Group-II than for Pile Group-I. For numerical investigation, the continuum approach method is utilised with the inclusion of a dynamic group interaction factor to predict the dynamic coupled responses in terms of frequency and amplitude for these two soil-pile setups. To understand the behaviour of pile groups, boundary zone parameters and variations of impedance parameters (stiffness and damping) with operating frequencies are also measured using this theoretical approach.
Geotechnical and Geological Engineering, Dec 13, 2019
The solution of slope stability problems requires determination of critical failure surface and a... more The solution of slope stability problems requires determination of critical failure surface and associated optimum/minimum factor of safety (FOS) value. Investigation of critical failure surface in any soil slope can be posed as a constrained global optimization problem. In this article, a simplified technique of generation of segmented non-circular failure surface is proposed. Unified particle swarm optimization (UPSO) method is utilized to search for the critical failure surface and associated minimum FOS of the slope. Limit equilibrium technique-based Morgenstern–Price method is used to evaluate the FOS value of the potential failure mass which satisfy both force as well as moment equilibrium. To demonstrate the performance of UPSO and its competence in yielding critical failure surface along with minimum FOS value, three benchmark problems with differing complexities are chosen from existing literatures. The results obtained are compared and are found to be in accord with the published literatures. The performance of UPSO as a solution algorithm for slope problems are established through convergence studies of various related parameters.
Geotechnical and Geological Engineering, May 17, 2020
In this study, seepage through the body of an earthen embankment for construction of railway line... more In this study, seepage through the body of an earthen embankment for construction of railway lines in Mokama in Bihar is estimated using finite element method. Seepage of water through the body of earthen embankment adversely affects its stability. In order to check the reliability of the constructed railway embankment stretching for a long distance, Random Finite Element Method (RFEM) originally developed by is used. The influence of variability in spatially distributed hydraulic conductivity/permeability field of the embankment is investigated by carrying out seepage analysis. Local Averaging Subdivision (LAS) technique is used to build the random field of hydraulic conductivity of soil domain under consideration. Afterwards, Monte Carlo simulation is performed for 1000 such random fields. The mean of total flow rate m Q ð Þ, mean of logarithmic of total flow rate m ln Q ð Þ and variance of logarithmic of total flow rate s 2 ln Q from seepage analyses for 1000 realizations of random field are reported. The results show that as the correlation length decreases, the output parameters m Q , m ln Q and s 2 ln Q follow a decreasing trend and vice versa. These variations are studied for the embankment with and without drain. The effect of drain on the mean hydraulic conductivity and hydraulic gradient standard deviation of the embankment are investigated in which the embankment with drains is found safer than embankment without drain.
Geotechnical and Geological Engineering, Oct 18, 2019
The districts of Madhubani and Supaul lie near Bihar-Nepal border along foothills of Himalaya. Di... more The districts of Madhubani and Supaul lie near Bihar-Nepal border along foothills of Himalaya. Different attenuation relationships applicable for the Himalayan region have been used to estimate the sitespecific Peak Ground Acceleration (PGA) for the Madhubani and Supaul region on the basis of Deterministic Seismic Hazard Assessment (DSHA) study. Seismicity data have been collected from IMD, New Delhi and forty seismotectonic sources were recognized in the region from Seismotectonic Atlas of India (GSI in Seismotectonic atlas of India and its environs, Geological Survey of India, Kolkata, 2000). Hypocentral distances have been measured using ArcGIS software. Maximum Peak ground acceleration value is found to occur for Main Central Thrust fault for both these districts.
This article presents results of slope analyses employing a simple technique of generating segmen... more This article presents results of slope analyses employing a simple technique of generating segmented non-circular failure surfaces. The formulation of slope analysis is performed as an optimization problem with four constrained control variables characterizing the failure surface. In this study, different variants of particle swarm optimization (PSO) methods such as inertia weight equipped and contemporary standard PSO (CS-PSO) are utilized to obtain optimum control variables and associated critical failure surface. The factor of safety of the slope or the objective function of the constrained optimization problem is determined by Morgenstern-Price method. To explore the competence of proposed method with different PSO models, three benchmark problems are analysed for different maximum number of function evaluations such as 1000, 2500 and 5000. A series of sensitivity analyses are performed for various parameters such as swarm size with maximum iteration count of 100. The swarm diversity behaviour is also studied in relation with converged or promising global optimum solution. It is found that contemporary standard PSO (CS-PSO) with or without velocity clamping maintains better swarm diversity and preserves the balance between swarm "exploration" and "exploitation" efficiently. Velocity clamping and positional clamping are recommended as they prevent the solution/control variable from overflying the swarm best position.
Beni-Suef University Journal of Basic and Applied Sciences
Background It is a well-known fact that the safety of slopes majorly depends on several factors s... more Background It is a well-known fact that the safety of slopes majorly depends on several factors such as geometry, soil properties. The safety factor might change significantly depending on the soil type and the slope’s shape. The knowledge of the nature of the change in the safety factor due to the change in the slope’s height and angle is essential for implementing an effective strategy of increasing the safety factor for any slope stability problem. The influence of geometric shapes on the stability of the slope needs to be properly investigated through three-dimensional slope stability analysis, as the three-dimensional analysis is suitable for all slopes, even those which invalidate the plane-strain conditions. Results To calculate the three-dimensional safety factor, multiple analyses of three homogenous soil slopes with different soil properties were conducted by varying slope height, angle, and combinations. Each slope's height and angle were recorded to identify the type...
In the past, numerous stratovolcanoes worldwide witnessed catastrophic flank collapses. One of th... more In the past, numerous stratovolcanoes worldwide witnessed catastrophic flank collapses. One of the greatest risks associated with stratovolcanoes is a massive rock failure. On 18 May 1980, we witnessed a rock slope failure due to a volcano eruption, and a 2185.60 m high rock slope of Mount St. Helens was collapsed. Thus, from the serviceability perspective, this work presents an effective computational technique to perform probabilistic analyses of Mount St. Helens situated in Washington, USA. Using the first-order second-moment method, probability theory and statistics were employed to map the uncertainties in rock parameters. Initially, Scoops3D was used to perform slope stability analysis followed by probabilistic evaluation using a hybrid computational model of artificial neural network (ANN) and firefly algorithm (FF), i.e., ANN-FF. The performance of the ANN-FF model was examined and compared with that of conventional ANN and other hybrid ANNs built using seven additional meta...
The main objective of the current investigation is to study the dynamic behaviour of a 3-pile gro... more The main objective of the current investigation is to study the dynamic behaviour of a 3-pile group with two different arrangements of pile setups under coupled (horizontal and rocking) excitations. To accomplish this objective, machine-induced field excitation tests are conducted on small-scale hollow steel piles. The 3-pile group is driven into the ground in a triangular arrangement with 3d spacing. Two different soil-pile setups, i.e., Pile Group-I and Pile Group-II, are created based on dynamic force directions. In the case of Pile Group-I, the forces are applied to the direction of the median of the triangle, and for Pile Group-II, the forces are applied to other directional loads. From the test results, it is found that the resonant peaks of horizontal and rocking amplitudes for Pile Group-I are lower than Pile Group-II. In the case of resonant frequencies, the values of Pile Group-I are observed to be the same or a little bit higher as compared to Pile Group-II. It is found t...
Uploads
Papers by Avijit Burman