Naresh Tamrakar | Tribhuvan University (original) (raw)
Papers by Naresh Tamrakar
NAAR, 2024
Construction activities are rapidly conducted in all parts of the country. Most important materia... more Construction activities are rapidly conducted in all parts of the country. Most important material in those activities is construction material. Mostly sands from the river are used in construction works, which with excessive mining can create various negative effects in the environment. It is essential to search for the alternative of the river sand, which in this case can be crushed rock sand from medium-to coarse-grained sandstones. Therefore, sands from both river and bedrocks were tested for grain size, shape, composition and physical properties. Comparison of particle size analysis with suitable standard gives suitability of both types of sands for general purpose mortar, floor screeding, plastering and rendering. Crushed rock sands are suitable for general purpose mortar and the river sand are more suitable for floor screeding, plastering and rendering purposes. Crushed-rock sands have slightly less specific gravity, more water absorption value and more organic content than those of the river sands. Unconfined compressive strength (UCS) of mortar cube made from crushed-rock sand have slightly less strength in 7 days of curing but have slightly greater strength in 28 days of curing than UCS river sands. This makes crushed-rock sands useable in structures requiring strength in long term and can also be an alternative for river sands.
Journal of Nepal Geological Society, Nov 1, 2011
Journal of Nepal Geological Society, Aug 21, 2023
Bulletin of the Department of Geology, Dec 31, 2022
AGU Fall Meeting Abstracts, Dec 1, 2018
American journal of science, engineering and technology, Jan 20, 2017
The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malek... more The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malekhu-Thopal Khola can lead to the instability of stream bank slope. The road of the Malekhu Khola corridor has been extended from the Prithvi Highway to the southern remote area, and the road of the Thopal Khola corridor has been extended from the Prithvi Highway to the North in Dhading Besi. The study is focused on the Slope Mass Rating (SMR) of the road cut slope as well as the streambank slopes along the Malekhu Khola and the Thopal Khola (Malekhu-Dhading road).The result shows that the 38% slope of the study area is stable in terms of plane failure. The slopes lying across the Malekhu Formation and the Kalitar Formation are unstable. Considering the slopes in terms of toppling failure, 41% of the slopes are found to be stable, whereas some range from partially stable to stable slopes to the partially stable to the unstable slopes. Similarly, 50% of the slopes are stable to partially stable in terms of wedge failure, whereas some other slopes lying in the Fagfog Quartzite, Malekhu Limestone, Kalitar Formation and the Kulekhani Formation lie in unstable slope category. If the slope stability of the whole stream corridor is considered, only 20-25% of the slope area is completely stable while the remaining is vulnerable due to various slope failures.
Journal of Nepal Geological Society, Dec 1, 2002
Journal of Nepal Geological Society, Dec 1, 2004
Bulletin of the Department of Geology, Dec 1, 2016
Dhamilo Khola, Lubu Khola and the Charkhande Khola. The lower order streams flow across the metas... more Dhamilo Khola, Lubu Khola and the Charkhande Khola. The lower order streams flow across the metasedimentary rocks whereas the higher order streams flow on the fluvio-lacustrine deposits. Sediment size distribution, hydraulic parameters, planform analysis, environment of deposition are important to characterise the stream (Shrestha and Tamrakar, 2007a; Tamrakar et al., 2011). Based on classification and competence evaluation, behaviour and nature of the river can be traced out. It is known that sediments in the stream have their origin from different sources. Therefore, the proportion of components that each source contributes to the mix varies over time and space, as a result of erosion processes that are ongoing in the basin of contribution. In addition, erosion and
Boletin de Geología, Jun 1, 2008
Journal of Nepal Geological Society, Oct 9, 2006
Journal of Nepal Geological Society, Oct 13, 2002
Journal of Nepal Geological Society, Dec 1, 2000
Journal of Nepal Geological Society, Dec 2, 2013
Journal of Nepal Geological Society, Jun 4, 2018
Field-based assessment of rock discontinuity and geological attributes of rock mass for stones fo... more Field-based assessment of rock discontinuity and geological attributes of rock mass for stones for various engineering applications INTRODUCTION Natural stones are naturally occurring rock types used for various purposes such as walling, paving, or roofing materials in construction after different procedure of cutting or shaping. The use and demand of natural stones for various engineering purposes have been increased with urbanization in the remote areas of Nepal. Various studies have been carried out for the recognition of various rock types for dimension stones in Nepal (Ghimire and Napit, 2008; Shrestha and Napit, 2003; Singh and Tamrakar, 2013). However, the study of the most promising and prospective rock types is still lacking. Currently, a number of methods are being used for the assessment of discontinuity analysis (Palmström, 2001; Wang et al., 2003; Smith, 2004). In reference to research problem, this study is a kind of support to explore the rock types and their characteristics based on discontinuity analysis and geological attributes.
Journal of Nepal Geological Society, Dec 1, 2004
Bulletin of the Department of Geology, 1970
Five representative segments of the river were surveyed in detail for evaluating its dynamics and... more Five representative segments of the river were surveyed in detail for evaluating its dynamics and stability condition. The first (downstream) to the fifth (upstream) segments are classified as 'F4', 'C4', 'C4', 'B4' and 'B4' streams characterised by gravelly substrates. All these streams are competent enough to transport their bed material (d 90) as shown by the exceeding dimensionless shear stress over critical dimensionless shear stress of the river segments. The existing depth and slope of the river is far enough to carry d 90 of the substrate grain size. Stream power of segments 1 to 5 are respectively, 622.6, 79.0, 146.6, 354.6 and 15617.0 KN/s. The 'B4' streams show greater stream power, i.e., transport capacity compared to 'F4' followed by 'C4' streams. Therefore, the 'B4 streams (3rd and 4th order streams) are potential to degradation, and the 'C4' and 'F4' (both 5th order) streams are potential to aggradation depending on river morphology and dynamics. Meander geometry of the Manahara River exhibit deviation of variables (meander wavelength vs channel width, and meander belt width vs channel width) from the stability, suggesting existence of instability to some extent in the river.
Zenodo (CERN European Organization for Nuclear Research), Aug 3, 2022
The Pantale Khola and the Thado Khola both are the fourth order streams originating from the Chur... more The Pantale Khola and the Thado Khola both are the fourth order streams originating from the Churia Hills and flowing on the gravelly terrain towards the north and ultimately mixing to the Rapati Nadi. The total area of the study area is 64 km 2. The fluvial condition of these streams originating from the Churia Hills along with their characteristics, sediment transport and sediment dynamics were studied. Geomorphic characterization of both the streams were accomplished using the help of topographic maps and satellite imageries. Five stream transects on each of the stream were surveyed for cross-sections and longitudinal profiles. Samples were collected from the thalweg of each transect for suspended sediment concentration and Wolman's pebble counting method was applied for establishing grain size distribution. The Rosgen classification of streams was applied to classify the stream reaches. Manning's roughness coefficient was calculated on the features as seen on the field and hence discharge was calculated. The streams have been classified as F4 type for the Pantale Khola and F4, F4b types for the Thado Khola. The bed load was calculated and hence total sediment load was also calculated. Both the streams show the eroding potential as found out from the stream power.
Journal of Nepal Geological Society, Sep 25, 2009
The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malek... more The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malekhu-Thopal Khola can lead to the instability of stream bank slope. The road of the Malekhu Khola corridor has been extended from the Prithvi Highway to the southern remote area, and the road of the Thopal Khola corridor has been extended from the Prithvi Highway to the North in Dhading Besi. The study is focused on the Slope Mass Rating (SMR) of the road cut slope as well as the streambank slopes along the Malekhu Khola and the Thopal Khola (Malekhu-Dhading road).The result shows that the 38% slope of the study area is stable in terms of plane failure. The slopes lying across the Malekhu Formation and the Kalitar Formation are unstable. Considering the slopes in terms of toppling failure, 41% of the slopes are found to be stable, whereas some range from partially stable to stable slopes to the partially stable to the unstable slopes. Similarly, 50% of the slopes are stable to partially st...
NAAR, 2024
Construction activities are rapidly conducted in all parts of the country. Most important materia... more Construction activities are rapidly conducted in all parts of the country. Most important material in those activities is construction material. Mostly sands from the river are used in construction works, which with excessive mining can create various negative effects in the environment. It is essential to search for the alternative of the river sand, which in this case can be crushed rock sand from medium-to coarse-grained sandstones. Therefore, sands from both river and bedrocks were tested for grain size, shape, composition and physical properties. Comparison of particle size analysis with suitable standard gives suitability of both types of sands for general purpose mortar, floor screeding, plastering and rendering. Crushed rock sands are suitable for general purpose mortar and the river sand are more suitable for floor screeding, plastering and rendering purposes. Crushed-rock sands have slightly less specific gravity, more water absorption value and more organic content than those of the river sands. Unconfined compressive strength (UCS) of mortar cube made from crushed-rock sand have slightly less strength in 7 days of curing but have slightly greater strength in 28 days of curing than UCS river sands. This makes crushed-rock sands useable in structures requiring strength in long term and can also be an alternative for river sands.
Journal of Nepal Geological Society, Nov 1, 2011
Journal of Nepal Geological Society, Aug 21, 2023
Bulletin of the Department of Geology, Dec 31, 2022
AGU Fall Meeting Abstracts, Dec 1, 2018
American journal of science, engineering and technology, Jan 20, 2017
The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malek... more The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malekhu-Thopal Khola can lead to the instability of stream bank slope. The road of the Malekhu Khola corridor has been extended from the Prithvi Highway to the southern remote area, and the road of the Thopal Khola corridor has been extended from the Prithvi Highway to the North in Dhading Besi. The study is focused on the Slope Mass Rating (SMR) of the road cut slope as well as the streambank slopes along the Malekhu Khola and the Thopal Khola (Malekhu-Dhading road).The result shows that the 38% slope of the study area is stable in terms of plane failure. The slopes lying across the Malekhu Formation and the Kalitar Formation are unstable. Considering the slopes in terms of toppling failure, 41% of the slopes are found to be stable, whereas some range from partially stable to stable slopes to the partially stable to the unstable slopes. Similarly, 50% of the slopes are stable to partially stable in terms of wedge failure, whereas some other slopes lying in the Fagfog Quartzite, Malekhu Limestone, Kalitar Formation and the Kulekhani Formation lie in unstable slope category. If the slope stability of the whole stream corridor is considered, only 20-25% of the slope area is completely stable while the remaining is vulnerable due to various slope failures.
Journal of Nepal Geological Society, Dec 1, 2002
Journal of Nepal Geological Society, Dec 1, 2004
Bulletin of the Department of Geology, Dec 1, 2016
Dhamilo Khola, Lubu Khola and the Charkhande Khola. The lower order streams flow across the metas... more Dhamilo Khola, Lubu Khola and the Charkhande Khola. The lower order streams flow across the metasedimentary rocks whereas the higher order streams flow on the fluvio-lacustrine deposits. Sediment size distribution, hydraulic parameters, planform analysis, environment of deposition are important to characterise the stream (Shrestha and Tamrakar, 2007a; Tamrakar et al., 2011). Based on classification and competence evaluation, behaviour and nature of the river can be traced out. It is known that sediments in the stream have their origin from different sources. Therefore, the proportion of components that each source contributes to the mix varies over time and space, as a result of erosion processes that are ongoing in the basin of contribution. In addition, erosion and
Boletin de Geología, Jun 1, 2008
Journal of Nepal Geological Society, Oct 9, 2006
Journal of Nepal Geological Society, Oct 13, 2002
Journal of Nepal Geological Society, Dec 1, 2000
Journal of Nepal Geological Society, Dec 2, 2013
Journal of Nepal Geological Society, Jun 4, 2018
Field-based assessment of rock discontinuity and geological attributes of rock mass for stones fo... more Field-based assessment of rock discontinuity and geological attributes of rock mass for stones for various engineering applications INTRODUCTION Natural stones are naturally occurring rock types used for various purposes such as walling, paving, or roofing materials in construction after different procedure of cutting or shaping. The use and demand of natural stones for various engineering purposes have been increased with urbanization in the remote areas of Nepal. Various studies have been carried out for the recognition of various rock types for dimension stones in Nepal (Ghimire and Napit, 2008; Shrestha and Napit, 2003; Singh and Tamrakar, 2013). However, the study of the most promising and prospective rock types is still lacking. Currently, a number of methods are being used for the assessment of discontinuity analysis (Palmström, 2001; Wang et al., 2003; Smith, 2004). In reference to research problem, this study is a kind of support to explore the rock types and their characteristics based on discontinuity analysis and geological attributes.
Journal of Nepal Geological Society, Dec 1, 2004
Bulletin of the Department of Geology, 1970
Five representative segments of the river were surveyed in detail for evaluating its dynamics and... more Five representative segments of the river were surveyed in detail for evaluating its dynamics and stability condition. The first (downstream) to the fifth (upstream) segments are classified as 'F4', 'C4', 'C4', 'B4' and 'B4' streams characterised by gravelly substrates. All these streams are competent enough to transport their bed material (d 90) as shown by the exceeding dimensionless shear stress over critical dimensionless shear stress of the river segments. The existing depth and slope of the river is far enough to carry d 90 of the substrate grain size. Stream power of segments 1 to 5 are respectively, 622.6, 79.0, 146.6, 354.6 and 15617.0 KN/s. The 'B4' streams show greater stream power, i.e., transport capacity compared to 'F4' followed by 'C4' streams. Therefore, the 'B4 streams (3rd and 4th order streams) are potential to degradation, and the 'C4' and 'F4' (both 5th order) streams are potential to aggradation depending on river morphology and dynamics. Meander geometry of the Manahara River exhibit deviation of variables (meander wavelength vs channel width, and meander belt width vs channel width) from the stability, suggesting existence of instability to some extent in the river.
Zenodo (CERN European Organization for Nuclear Research), Aug 3, 2022
The Pantale Khola and the Thado Khola both are the fourth order streams originating from the Chur... more The Pantale Khola and the Thado Khola both are the fourth order streams originating from the Churia Hills and flowing on the gravelly terrain towards the north and ultimately mixing to the Rapati Nadi. The total area of the study area is 64 km 2. The fluvial condition of these streams originating from the Churia Hills along with their characteristics, sediment transport and sediment dynamics were studied. Geomorphic characterization of both the streams were accomplished using the help of topographic maps and satellite imageries. Five stream transects on each of the stream were surveyed for cross-sections and longitudinal profiles. Samples were collected from the thalweg of each transect for suspended sediment concentration and Wolman's pebble counting method was applied for establishing grain size distribution. The Rosgen classification of streams was applied to classify the stream reaches. Manning's roughness coefficient was calculated on the features as seen on the field and hence discharge was calculated. The streams have been classified as F4 type for the Pantale Khola and F4, F4b types for the Thado Khola. The bed load was calculated and hence total sediment load was also calculated. Both the streams show the eroding potential as found out from the stream power.
Journal of Nepal Geological Society, Sep 25, 2009
The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malek... more The Malekhu-Thopal Khola area is rich in metamorphic rocks. The extension of road along the Malekhu-Thopal Khola can lead to the instability of stream bank slope. The road of the Malekhu Khola corridor has been extended from the Prithvi Highway to the southern remote area, and the road of the Thopal Khola corridor has been extended from the Prithvi Highway to the North in Dhading Besi. The study is focused on the Slope Mass Rating (SMR) of the road cut slope as well as the streambank slopes along the Malekhu Khola and the Thopal Khola (Malekhu-Dhading road).The result shows that the 38% slope of the study area is stable in terms of plane failure. The slopes lying across the Malekhu Formation and the Kalitar Formation are unstable. Considering the slopes in terms of toppling failure, 41% of the slopes are found to be stable, whereas some range from partially stable to stable slopes to the partially stable to the unstable slopes. Similarly, 50% of the slopes are stable to partially st...