Journal of Advanced College of Engineering and Management
Rapid urbanization and geological challenges in Kathmandu have made it crucial to understand the ... more Rapid urbanization and geological challenges in Kathmandu have made it crucial to understand the geotechnical properties of the soil in the region. This study here focuses on the undrained shear strength of silty clay in Kalimati, Kathmandu, and investigates the applicability of Vane Shear tests and its parameters over other shear strength tests from other methods. Geotechnical investigations were carried out at three locations within the Kathmandu Engineering College premises and in-situ and laboratory tests were conducted on undisturbed and disturbed samples. Then the study compared the field vane shear strength, undrained strength from unconfined compression tests, and laboratory vane shear strength of the samples. For the field vane shear test the correction factor as suggested by Bjerrum was used and the results indicate that this method overestimates the shear strength in Kalimati soil, indicating no adjustment is necessary. The findings of this study have important implicatio...
The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear ... more The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear test. Experimental investigations on two sands, one with rounded smooth grains (Ennore standard sand) and another with angular grains (Ganga sand), were carried out with a view to investigate the difference in shear strength of the sands at different shear strain rates. From the test results, it was found out that friction angle depends largely on gradation and particle angularity. Angular well-graded particles give the highest friction angle, and the rounded uniform particles give the least. Angle of shearing resistance increases with increasing the strain rate. For these two sands, relationships have also been established for prediction of peak friction angle as a function of relative density and rate of shearing strain.
On June 15, 2021, a disastrous debris flow occurred along the Melamchi River in central Nepal. Th... more On June 15, 2021, a disastrous debris flow occurred along the Melamchi River in central Nepal. The debris flow event lasted for some 10 hours and caused enormous losses of lives and property. At least 350 residential buildings, half a dozen of bridges, and many infrastructures were affected by the debris flow event. Immediately after the debris flow event, Nepal Engineers’ Association took an initiative to deploy a field reconnaissance mission comprising hydrologists, water resources engineers, structural engineers, geotechnical engineers, civil engineers, disaster risk reduction professionals, surveyors, and geologists. The field reconnaissance was conducted during June 20-24, 2021. This report presents a preliminary finding as observed by the study team and as obtained from preliminary analyses of various factors and consequences. damage observations, hydrological analyses, flood characterization, geotechnical and geological insights, and extensive characterization through terrestrial and aerial surveys of the event. The sum of findings highlights that the debris flow event was triggered by localized rainfall as debris was already deposited in the upstream side due to fragile geological formation, which was also triggered by the 2015 Gorkha earthquake. Similarly, the debris flow is characterized as a cascade of the 2015 Gorkha earthquake since the mass movements were fundamentally triggered by the Gorkha earthquake in lower and middle mountains. Moreover, the debris fans also contributed in sediment transport. The findings also highlight that the sediment transport occurred for about 30 km stretch. Especially, the soft sediment deposit was remarkably high throughout the river stretch. Preliminary analyses confirm that the riverbed was aggravated to a maximum of 15 m in most of the locations. The causes, consequences, and details of the debris flow event are presented systematically in this report from a multi-disciplinary perspective. This study further suggests a couple of recommendations for policy/program/practice as well as for further detailed study/research.
In book: Geotechnical Characterization and Modelling, Proceedings of IGC 2018, 2018
The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear ... more The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear test. Experimental investigations on two sands, one with rounded smooth grains (Ennore standard sand) and another with angular grains (Ganga sand), were carried out with a view to investigate the difference in shear strength of the sands at different shear strain rates. From the test results, it was found out that friction angle depends largely on gradation and particle angularity. Angular well-graded particles give the highest friction angle, and the rounded uniform particles give the least. Angle of shearing resistance increases with increasing the strain rate. For these two sands, relationships have also been established for prediction of peak friction angle as a function of relative density and rate of shearing strain.
Kathmandu Valley lies in an active tectonic zone, meaning that earthquakes are common in the regi... more Kathmandu Valley lies in an active tectonic zone, meaning that earthquakes are common in the region. The most recent was the Gorkha Nepal earthquake, measuring 7.8 Mw. Past earthquakes caused soil liquefaction in the valley with severe damages and destruction of existing critical infrastructures. As for such infrastructures, the road network, health facilities, schools and airports are considered. This paper presents a liquefaction susceptibility map. This map was obtained by computing the liquefaction potential index (LPI) for several boreholes with SPT measurements and clustering the areas with similar values of LPI. Moreover, the locations of existing critical infrastructures were reported on this risk map. Therefore, we noted that 42% of the road network and 16% of the airport area are in zones of very high liquefaction susceptibility, while 60%, 54%, and 64% of health facilities, schools and colleges are in very high liquefaction zones, respectively. This indicates that most of...
As good soil becomes scarcer and their location becomes even more difficult and costlier, the nee... more As good soil becomes scarcer and their location becomes even more difficult and costlier, the need to improve its quality using innovative new technique is becoming ever more important. This research involves a study on the possible use of waste plastic bottles as soil reinforcement elements. A series of tri-axial test were carried out on three different samples of soil prepared from typical soil used for routine construction in and around Kathmandu valley. The analysis was carried out by varying the percentage of plastic used varying from 0.5% to 1.5% by weight of dry soil. The results indicate 25% to 125% increase in shear strength of soil for an addition of 0.5% to 1.5% of plastic strips by weight of soil under laboratory conditions. The primary objective of this research is to find out an effective utilization of waste plastic bottles in the geotechnical engineering application, simultaneously addressing some aspects of solids waste management without adversely affecting the nat...
In this paper, Fly Ash which is obtained after burning coal in thermal power plants, is used as a... more In this paper, Fly Ash which is obtained after burning coal in thermal power plants, is used as a stabilizing agent to stabilize the expansive, compressible and low bearing capacity Kalimati Soil that causes possibility of failure of structures lying over them. The present paper evaluated the influence of Fly Ash on the index and engineering properties of soil by addition of 10%, 20%.30%.40% and 50% of Fly Ash as per weight of the total soil sample. The significant variation in Liquid Limit, Plasticity Index and Swelling Index has been found. In Kalimati Soil, the Liquid Limit decreased 1.03 times, Shrinkage Limit decreased 1.46 times and Differential Free Swell Index decreased 1.14 times. The compaction test results showed increase in Maximum Dry Density (MDD) from 1012.5 kg/m3 to 1162.5 kg/m3. The Unconfined Compression Strength (UCS) test showed that its value increased from 229.418 Kpa to 285.64 Kpa .XRD results showed that there is reduction in the amount of clay minerals with ...
A project named “Construction of AANSON Building at Sinamangal” is taken as a case study for the ... more A project named “Construction of AANSON Building at Sinamangal” is taken as a case study for the stability analysis of RCC Cantilever Retaining Wall with and without Pressure Relief Shelves. Modelling is done using Finite Element Method (STAAD Pro) using plate and 4 noded models. The earth pressure exerted by the back-fill soil and the underlaying soil is applied on the model after calculation of parameters. The investigations are carried out on some of the major factors like displacement of stem, heel and toe, bending moments, reactions etc. The result reveals that the pressure relief shelves could be used in RCC Cantilever retaining walls to make the structure more stable.
Journal of Advanced College of Engineering and Management
Rapid urbanization and geological challenges in Kathmandu have made it crucial to understand the ... more Rapid urbanization and geological challenges in Kathmandu have made it crucial to understand the geotechnical properties of the soil in the region. This study here focuses on the undrained shear strength of silty clay in Kalimati, Kathmandu, and investigates the applicability of Vane Shear tests and its parameters over other shear strength tests from other methods. Geotechnical investigations were carried out at three locations within the Kathmandu Engineering College premises and in-situ and laboratory tests were conducted on undisturbed and disturbed samples. Then the study compared the field vane shear strength, undrained strength from unconfined compression tests, and laboratory vane shear strength of the samples. For the field vane shear test the correction factor as suggested by Bjerrum was used and the results indicate that this method overestimates the shear strength in Kalimati soil, indicating no adjustment is necessary. The findings of this study have important implicatio...
The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear ... more The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear test. Experimental investigations on two sands, one with rounded smooth grains (Ennore standard sand) and another with angular grains (Ganga sand), were carried out with a view to investigate the difference in shear strength of the sands at different shear strain rates. From the test results, it was found out that friction angle depends largely on gradation and particle angularity. Angular well-graded particles give the highest friction angle, and the rounded uniform particles give the least. Angle of shearing resistance increases with increasing the strain rate. For these two sands, relationships have also been established for prediction of peak friction angle as a function of relative density and rate of shearing strain.
On June 15, 2021, a disastrous debris flow occurred along the Melamchi River in central Nepal. Th... more On June 15, 2021, a disastrous debris flow occurred along the Melamchi River in central Nepal. The debris flow event lasted for some 10 hours and caused enormous losses of lives and property. At least 350 residential buildings, half a dozen of bridges, and many infrastructures were affected by the debris flow event. Immediately after the debris flow event, Nepal Engineers’ Association took an initiative to deploy a field reconnaissance mission comprising hydrologists, water resources engineers, structural engineers, geotechnical engineers, civil engineers, disaster risk reduction professionals, surveyors, and geologists. The field reconnaissance was conducted during June 20-24, 2021. This report presents a preliminary finding as observed by the study team and as obtained from preliminary analyses of various factors and consequences. damage observations, hydrological analyses, flood characterization, geotechnical and geological insights, and extensive characterization through terrestrial and aerial surveys of the event. The sum of findings highlights that the debris flow event was triggered by localized rainfall as debris was already deposited in the upstream side due to fragile geological formation, which was also triggered by the 2015 Gorkha earthquake. Similarly, the debris flow is characterized as a cascade of the 2015 Gorkha earthquake since the mass movements were fundamentally triggered by the Gorkha earthquake in lower and middle mountains. Moreover, the debris fans also contributed in sediment transport. The findings also highlight that the sediment transport occurred for about 30 km stretch. Especially, the soft sediment deposit was remarkably high throughout the river stretch. Preliminary analyses confirm that the riverbed was aggravated to a maximum of 15 m in most of the locations. The causes, consequences, and details of the debris flow event are presented systematically in this report from a multi-disciplinary perspective. This study further suggests a couple of recommendations for policy/program/practice as well as for further detailed study/research.
In book: Geotechnical Characterization and Modelling, Proceedings of IGC 2018, 2018
The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear ... more The paper is mainly focused on the strain rate effect on shear strength of sands in direct shear test. Experimental investigations on two sands, one with rounded smooth grains (Ennore standard sand) and another with angular grains (Ganga sand), were carried out with a view to investigate the difference in shear strength of the sands at different shear strain rates. From the test results, it was found out that friction angle depends largely on gradation and particle angularity. Angular well-graded particles give the highest friction angle, and the rounded uniform particles give the least. Angle of shearing resistance increases with increasing the strain rate. For these two sands, relationships have also been established for prediction of peak friction angle as a function of relative density and rate of shearing strain.
Kathmandu Valley lies in an active tectonic zone, meaning that earthquakes are common in the regi... more Kathmandu Valley lies in an active tectonic zone, meaning that earthquakes are common in the region. The most recent was the Gorkha Nepal earthquake, measuring 7.8 Mw. Past earthquakes caused soil liquefaction in the valley with severe damages and destruction of existing critical infrastructures. As for such infrastructures, the road network, health facilities, schools and airports are considered. This paper presents a liquefaction susceptibility map. This map was obtained by computing the liquefaction potential index (LPI) for several boreholes with SPT measurements and clustering the areas with similar values of LPI. Moreover, the locations of existing critical infrastructures were reported on this risk map. Therefore, we noted that 42% of the road network and 16% of the airport area are in zones of very high liquefaction susceptibility, while 60%, 54%, and 64% of health facilities, schools and colleges are in very high liquefaction zones, respectively. This indicates that most of...
As good soil becomes scarcer and their location becomes even more difficult and costlier, the nee... more As good soil becomes scarcer and their location becomes even more difficult and costlier, the need to improve its quality using innovative new technique is becoming ever more important. This research involves a study on the possible use of waste plastic bottles as soil reinforcement elements. A series of tri-axial test were carried out on three different samples of soil prepared from typical soil used for routine construction in and around Kathmandu valley. The analysis was carried out by varying the percentage of plastic used varying from 0.5% to 1.5% by weight of dry soil. The results indicate 25% to 125% increase in shear strength of soil for an addition of 0.5% to 1.5% of plastic strips by weight of soil under laboratory conditions. The primary objective of this research is to find out an effective utilization of waste plastic bottles in the geotechnical engineering application, simultaneously addressing some aspects of solids waste management without adversely affecting the nat...
In this paper, Fly Ash which is obtained after burning coal in thermal power plants, is used as a... more In this paper, Fly Ash which is obtained after burning coal in thermal power plants, is used as a stabilizing agent to stabilize the expansive, compressible and low bearing capacity Kalimati Soil that causes possibility of failure of structures lying over them. The present paper evaluated the influence of Fly Ash on the index and engineering properties of soil by addition of 10%, 20%.30%.40% and 50% of Fly Ash as per weight of the total soil sample. The significant variation in Liquid Limit, Plasticity Index and Swelling Index has been found. In Kalimati Soil, the Liquid Limit decreased 1.03 times, Shrinkage Limit decreased 1.46 times and Differential Free Swell Index decreased 1.14 times. The compaction test results showed increase in Maximum Dry Density (MDD) from 1012.5 kg/m3 to 1162.5 kg/m3. The Unconfined Compression Strength (UCS) test showed that its value increased from 229.418 Kpa to 285.64 Kpa .XRD results showed that there is reduction in the amount of clay minerals with ...
A project named “Construction of AANSON Building at Sinamangal” is taken as a case study for the ... more A project named “Construction of AANSON Building at Sinamangal” is taken as a case study for the stability analysis of RCC Cantilever Retaining Wall with and without Pressure Relief Shelves. Modelling is done using Finite Element Method (STAAD Pro) using plate and 4 noded models. The earth pressure exerted by the back-fill soil and the underlaying soil is applied on the model after calculation of parameters. The investigations are carried out on some of the major factors like displacement of stem, heel and toe, bending moments, reactions etc. The result reveals that the pressure relief shelves could be used in RCC Cantilever retaining walls to make the structure more stable.
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Papers by Indra Acharya