Rajinder Bhasin - Academia.edu (original) (raw)
Papers by Rajinder Bhasin
T T International, 2003
... Anette Wold Hagen, project engineering geologist, Dr Amir Kaynia, senior engineer, from the N... more ... Anette Wold Hagen, project engineering geologist, Dr Amir Kaynia, senior engineer, from the Norwegian Geotechnical Institute and Kalpana Kankes, Technical University of Stockholm, conclude the update of the Q-system for lining design Revue / Journal Title. ...
Geomatics, Natural Hazards and Risk, 2015
Finite element analysis of failed slope of the Surabhi Resort landslide located in the Mussoorie ... more Finite element analysis of failed slope of the Surabhi Resort landslide located in the Mussoorie township, Garhwal Himalaya has been carried out using shear strength reduction technique. Two slope models viz. debris and rock mass were taken into consideration in this study and have been analysed for possible failure of slope in future. Critical strength reduction factor (SRF) for the failed slope is observed to be 0.28 and 0.83 for the debris and rock mass model, respectively. A low SRF value of the slope revealed significant progressive displacement in the zone of detachment. This has also been evidenced in the form of cracks in the building of Surabhi Resort and presence of subsidence zones in the Mussoorie International School. These results are consistent with the study carried out by other workers using different approach.
Geological Society, London, Engineering Geology Special Publications, 1996
Landslide Science and Practice, 2013
Landslide Science and Practice, 2013
KSCE Journal of Civil Engineering, 2014
ABSTRACT Numerical simulations have been performed to assess the stability of a large underground... more ABSTRACT Numerical simulations have been performed to assess the stability of a large underground powerhouse in the Himalayas, using both finite element and distinct element approaches. Large convergences (around 250–300 mm) along the 45 m high wall of the Machine Hall have been measured by total station measurements during construction and up to 60 mm in the post construction and operational phase. Displacements are continuing at a reduced rate of about 3 to 6 mm per year. A large number of rock bolts have failed in the powerhouse and the shotcrete liner presents cracks and failure marks, thus questioning the long-term integrity and stability of the existing rock support system. The purpose of the numerical analysis was to back-calculate the prevailing rock mass conditions surrounding the machine hall, thereby gaining a better understanding of the mechanisms responsible for the instability in the cavern. The results from the analysis indicate that there was possibly an underestimation of the rock support requirements needed for the cavern, coupled with a not so good installation (incomplete grouting of the bolts). Both the length and the capacity of the rock bolts were underestimated presumably due to the existence of a high stress regime in the area, which may not have been taken into consideration in the design of rock support. The effect of a possible earthquake, frequent in this area, has also been studied and proves to induce a significant increase of the displacements and the support failure.
Tunnelling and Underground Space Technology, 2006
Landslide Science and Practice, 2013
Regional landslide hazard prediction and warning are still difficult targets to be achieved and a... more Regional landslide hazard prediction and warning are still difficult targets to be achieved and a hot topic in the research of landslide hazards. It is necessary to investigate the possibility of interpreting landslide events in terms of the rainfall patterns immediately preceding the slide event. This can be further enhanced by taking the lithological conditions in to account. Rainfall threshold values vary from region to region due to differences in exiting soil characteristics and climatological patterns in different areas. This paper addresses the needs mentioned above and it includes the data and methods for recommending threshold values adopted by countries, such as Bhutan,
Landslides: Global Risk Preparedness, 2012
Landslide Science for a Safer Geoenvironment, 2014
Chittagong, the second largest city of Bangladesh, is mostly developed in the hilly areas. Hills ... more Chittagong, the second largest city of Bangladesh, is mostly developed in the hilly areas. Hills are mostly covered with loose and weathered tertiary sedimentary rocks susceptible to landslides. Generally, during heavy rainfall within a short time, water infiltrates into the loose rocks and soils, which increase the pore water pressure, and finally exceeds the shear strength of the materials to initiate landslides. Landslides history, slope characteristics, geology and geotechnical properties have been considered to divide Chittagong City and surrounding areas into four landslide hazard zones. Zone I in the east of Chittagong City persists as the most susceptible area for landslides, and the city becomes gradually less susceptible further westward up to zone IV. Prevention of landslides in most cases requires costly engineering solutions. Therefore, mitigation through timely evacuation of people from hazardous areas might be a good solution to combat landslides. Two automated rain gauges are installed at high risk landslide zones with built-in rainfall threshold values. Threshold values for early warning of landslides are set after statistical analysis of past landslides in relation to total amount of rainfall and local geology. The threshold values of rainfall are set to 100 mm in 3 h, 200 mm in 24 h and 350 mm in 72 h.
Tunnelling and Underground Space Technology, 1996
A method of predicting probable ground behaviour considering stress-strength relatioaships is pre... more A method of predicting probable ground behaviour considering stress-strength relatioaships is presented. The influence of overburden pressure and rock mass strength which are implicitly used in calculating the Q value (Q-system of Barton et al. 1974) are explicitly considered in forecasting stability problems in tunnels. In particular, squeezing, spalling and loosening of the rock mass in tunnels constructed through the complex geological setup of the Himalayas have been analysed. A new Q-system correlation which takes into account the dimension of an opening is suggested for evaluating support pressures in squeezing ground. Rdsumd-Cet article prdsente une rn~thode de prddire le comportement probable du sol en fonction des relations de pression et de force. L'influence de la pression surchargde et la force de la masse duroc qui entre implicitement dans le calcul du valeur de Q est explicitement considdrde en faisant la prdvision des probl~mes de stabilitd dans les tunnels. En particulier, on a analysd la compression, le spalling et l'ameublissernent de la roche des tunnels construits d travers la complexe structure gdologique des Himalayas. Un nouveau syst~me de Q corrdlation qui tient compte de la dimension d' une ouverture est suggdrd pour l'dvaluation des pressions de soutien clans le procdde de la compression du sol.
Tunnelling and Underground Space Technology, 1997
Two-dimensional numerical experiments are conducted for investigating the effects of block size a... more Two-dimensional numerical experiments are conducted for investigating the effects of block size and joint properties on the behaviour of multiply jointed rock. The paper explains how the size of the individual blocks controls both the shear strength of the assembly (rock mass) and its deformational characteristics. A closely, jointed rock mass, in which block rotations occur, exhibits a lower stiffness but a higher strength than a rock mass with widely spaced joints. These numerical results are similar to those from reported physical model tests on jointed slabs of a rock model material. The paper shows how parametric studies on a single joint using the Barton-Bandis (BB) formulation are useful for providing information about the response of a jointed rock mass.
Tunnelling and Underground Space Technology, 2007
Rock Mechanics and Rock Engineering, 2012
Stability analysis of Surabhi landslide in the Dehradun and Tehri districts of Uttaranchal locate... more Stability analysis of Surabhi landslide in the Dehradun and Tehri districts of Uttaranchal located in Mussoorie, India, has been simulated numerically using the distinct element method focusing on the weak zones (fracture). This is an active landslide on the main road toward the town centre, which was triggered after rainfall in July-August 1998. Understanding the behaviour of this landslide will be helpful for planning and implementing mitigation measures. The first stage of the study includes the total area of the landslide. The area identified as the zone of detachment is considered the most vulnerable part of the landslide. Ingress of water and increased pore pressures result in reduced mobilized effective frictional resistance, causing the top layer of the zone of detachment to start moving. The corresponding total volume of rock mass that is potentially unstable is estimated to 11.58 million m 3. The second stage of this study includes a 2D model focussing only on the zone of detachment. The result of the analyses including both static and dynamic loading indicates that most of the total displacement observed in the slide model is due to the zone of detachment. The discontinuum modelling in the present study gives reasonable agreement with actual observations and has improved understanding of the stability of the slide slope.
Report, Norwegian …, 2002
... Eystein Grimstad, Kalpana Kankes, Rajinder Bhasin, Anette Wold Magnussen, and Amir Kaynia Nor... more ... Eystein Grimstad, Kalpana Kankes, Rajinder Bhasin, Anette Wold Magnussen, and Amir Kaynia Norwegian Geotechnical Institute, Norway. SUMMARY ... This tunnel may have a long-term total deformation in the order of 10 mm with minor support. ...
International Journal of Rock Mechanics and Mining Sciences, 2009
The seismic stability of the Åknes rock slope, western Norway, was analysed by using the distinct... more The seismic stability of the Åknes rock slope, western Norway, was analysed by using the distinct element code UDEC (Universal Distinct Element Code). The slope poses a threat to the region as a sudden failure may cause a destructive tsunami in the fjord. The dynamic input was based on earthquakes with return periods of 100 and 1000 years, and in
International Journal of Rock Mechanics and Mining Sciences, 1998
Parametric studies are performed using the distinct element computer program UDEC-BB for a large ... more Parametric studies are performed using the distinct element computer program UDEC-BB for a large cavern in the Himalayas. The studies provide insights into some important deformation mechanisms in a numerical system of blocks. The sensitivity studies involving changes in joint spacings (block size) revealed that the deformations around an opening are dependent on the size or the number of blocks adjacent to the excavation. Large size blocks deform mainly through translational shear upon which rotational shear may occur. In a model in whieh the block size is small compared to the tunnel dimensions, the tendency to dilation across an increased number of non-planar joints may contribute to interlocking of blocks. The BB joint behavioural model which allows the modelling of the dilation accompanying shear and hence the build-up of higher normal stresses, predicts smaller deformations than the Mohr-Coulomb model in which the dilation angle is constant. The sensitivity studies involving changes in key BB joint shear strength parameters have shown that, within the range of values considered, the model output is relatively insensitive to assumed joint strength parameters joint roughness coefficient and (at. However, an increase in the joint wall compressive strength contributes to an increase in the joint shear strength resulting in a marked reduction of displacements around the opening.
T T International, 2003
... Anette Wold Hagen, project engineering geologist, Dr Amir Kaynia, senior engineer, from the N... more ... Anette Wold Hagen, project engineering geologist, Dr Amir Kaynia, senior engineer, from the Norwegian Geotechnical Institute and Kalpana Kankes, Technical University of Stockholm, conclude the update of the Q-system for lining design Revue / Journal Title. ...
Geomatics, Natural Hazards and Risk, 2015
Finite element analysis of failed slope of the Surabhi Resort landslide located in the Mussoorie ... more Finite element analysis of failed slope of the Surabhi Resort landslide located in the Mussoorie township, Garhwal Himalaya has been carried out using shear strength reduction technique. Two slope models viz. debris and rock mass were taken into consideration in this study and have been analysed for possible failure of slope in future. Critical strength reduction factor (SRF) for the failed slope is observed to be 0.28 and 0.83 for the debris and rock mass model, respectively. A low SRF value of the slope revealed significant progressive displacement in the zone of detachment. This has also been evidenced in the form of cracks in the building of Surabhi Resort and presence of subsidence zones in the Mussoorie International School. These results are consistent with the study carried out by other workers using different approach.
Geological Society, London, Engineering Geology Special Publications, 1996
Landslide Science and Practice, 2013
Landslide Science and Practice, 2013
KSCE Journal of Civil Engineering, 2014
ABSTRACT Numerical simulations have been performed to assess the stability of a large underground... more ABSTRACT Numerical simulations have been performed to assess the stability of a large underground powerhouse in the Himalayas, using both finite element and distinct element approaches. Large convergences (around 250–300 mm) along the 45 m high wall of the Machine Hall have been measured by total station measurements during construction and up to 60 mm in the post construction and operational phase. Displacements are continuing at a reduced rate of about 3 to 6 mm per year. A large number of rock bolts have failed in the powerhouse and the shotcrete liner presents cracks and failure marks, thus questioning the long-term integrity and stability of the existing rock support system. The purpose of the numerical analysis was to back-calculate the prevailing rock mass conditions surrounding the machine hall, thereby gaining a better understanding of the mechanisms responsible for the instability in the cavern. The results from the analysis indicate that there was possibly an underestimation of the rock support requirements needed for the cavern, coupled with a not so good installation (incomplete grouting of the bolts). Both the length and the capacity of the rock bolts were underestimated presumably due to the existence of a high stress regime in the area, which may not have been taken into consideration in the design of rock support. The effect of a possible earthquake, frequent in this area, has also been studied and proves to induce a significant increase of the displacements and the support failure.
Tunnelling and Underground Space Technology, 2006
Landslide Science and Practice, 2013
Regional landslide hazard prediction and warning are still difficult targets to be achieved and a... more Regional landslide hazard prediction and warning are still difficult targets to be achieved and a hot topic in the research of landslide hazards. It is necessary to investigate the possibility of interpreting landslide events in terms of the rainfall patterns immediately preceding the slide event. This can be further enhanced by taking the lithological conditions in to account. Rainfall threshold values vary from region to region due to differences in exiting soil characteristics and climatological patterns in different areas. This paper addresses the needs mentioned above and it includes the data and methods for recommending threshold values adopted by countries, such as Bhutan,
Landslides: Global Risk Preparedness, 2012
Landslide Science for a Safer Geoenvironment, 2014
Chittagong, the second largest city of Bangladesh, is mostly developed in the hilly areas. Hills ... more Chittagong, the second largest city of Bangladesh, is mostly developed in the hilly areas. Hills are mostly covered with loose and weathered tertiary sedimentary rocks susceptible to landslides. Generally, during heavy rainfall within a short time, water infiltrates into the loose rocks and soils, which increase the pore water pressure, and finally exceeds the shear strength of the materials to initiate landslides. Landslides history, slope characteristics, geology and geotechnical properties have been considered to divide Chittagong City and surrounding areas into four landslide hazard zones. Zone I in the east of Chittagong City persists as the most susceptible area for landslides, and the city becomes gradually less susceptible further westward up to zone IV. Prevention of landslides in most cases requires costly engineering solutions. Therefore, mitigation through timely evacuation of people from hazardous areas might be a good solution to combat landslides. Two automated rain gauges are installed at high risk landslide zones with built-in rainfall threshold values. Threshold values for early warning of landslides are set after statistical analysis of past landslides in relation to total amount of rainfall and local geology. The threshold values of rainfall are set to 100 mm in 3 h, 200 mm in 24 h and 350 mm in 72 h.
Tunnelling and Underground Space Technology, 1996
A method of predicting probable ground behaviour considering stress-strength relatioaships is pre... more A method of predicting probable ground behaviour considering stress-strength relatioaships is presented. The influence of overburden pressure and rock mass strength which are implicitly used in calculating the Q value (Q-system of Barton et al. 1974) are explicitly considered in forecasting stability problems in tunnels. In particular, squeezing, spalling and loosening of the rock mass in tunnels constructed through the complex geological setup of the Himalayas have been analysed. A new Q-system correlation which takes into account the dimension of an opening is suggested for evaluating support pressures in squeezing ground. Rdsumd-Cet article prdsente une rn~thode de prddire le comportement probable du sol en fonction des relations de pression et de force. L'influence de la pression surchargde et la force de la masse duroc qui entre implicitement dans le calcul du valeur de Q est explicitement considdrde en faisant la prdvision des probl~mes de stabilitd dans les tunnels. En particulier, on a analysd la compression, le spalling et l'ameublissernent de la roche des tunnels construits d travers la complexe structure gdologique des Himalayas. Un nouveau syst~me de Q corrdlation qui tient compte de la dimension d' une ouverture est suggdrd pour l'dvaluation des pressions de soutien clans le procdde de la compression du sol.
Tunnelling and Underground Space Technology, 1997
Two-dimensional numerical experiments are conducted for investigating the effects of block size a... more Two-dimensional numerical experiments are conducted for investigating the effects of block size and joint properties on the behaviour of multiply jointed rock. The paper explains how the size of the individual blocks controls both the shear strength of the assembly (rock mass) and its deformational characteristics. A closely, jointed rock mass, in which block rotations occur, exhibits a lower stiffness but a higher strength than a rock mass with widely spaced joints. These numerical results are similar to those from reported physical model tests on jointed slabs of a rock model material. The paper shows how parametric studies on a single joint using the Barton-Bandis (BB) formulation are useful for providing information about the response of a jointed rock mass.
Tunnelling and Underground Space Technology, 2007
Rock Mechanics and Rock Engineering, 2012
Stability analysis of Surabhi landslide in the Dehradun and Tehri districts of Uttaranchal locate... more Stability analysis of Surabhi landslide in the Dehradun and Tehri districts of Uttaranchal located in Mussoorie, India, has been simulated numerically using the distinct element method focusing on the weak zones (fracture). This is an active landslide on the main road toward the town centre, which was triggered after rainfall in July-August 1998. Understanding the behaviour of this landslide will be helpful for planning and implementing mitigation measures. The first stage of the study includes the total area of the landslide. The area identified as the zone of detachment is considered the most vulnerable part of the landslide. Ingress of water and increased pore pressures result in reduced mobilized effective frictional resistance, causing the top layer of the zone of detachment to start moving. The corresponding total volume of rock mass that is potentially unstable is estimated to 11.58 million m 3. The second stage of this study includes a 2D model focussing only on the zone of detachment. The result of the analyses including both static and dynamic loading indicates that most of the total displacement observed in the slide model is due to the zone of detachment. The discontinuum modelling in the present study gives reasonable agreement with actual observations and has improved understanding of the stability of the slide slope.
Report, Norwegian …, 2002
... Eystein Grimstad, Kalpana Kankes, Rajinder Bhasin, Anette Wold Magnussen, and Amir Kaynia Nor... more ... Eystein Grimstad, Kalpana Kankes, Rajinder Bhasin, Anette Wold Magnussen, and Amir Kaynia Norwegian Geotechnical Institute, Norway. SUMMARY ... This tunnel may have a long-term total deformation in the order of 10 mm with minor support. ...
International Journal of Rock Mechanics and Mining Sciences, 2009
The seismic stability of the Åknes rock slope, western Norway, was analysed by using the distinct... more The seismic stability of the Åknes rock slope, western Norway, was analysed by using the distinct element code UDEC (Universal Distinct Element Code). The slope poses a threat to the region as a sudden failure may cause a destructive tsunami in the fjord. The dynamic input was based on earthquakes with return periods of 100 and 1000 years, and in
International Journal of Rock Mechanics and Mining Sciences, 1998
Parametric studies are performed using the distinct element computer program UDEC-BB for a large ... more Parametric studies are performed using the distinct element computer program UDEC-BB for a large cavern in the Himalayas. The studies provide insights into some important deformation mechanisms in a numerical system of blocks. The sensitivity studies involving changes in joint spacings (block size) revealed that the deformations around an opening are dependent on the size or the number of blocks adjacent to the excavation. Large size blocks deform mainly through translational shear upon which rotational shear may occur. In a model in whieh the block size is small compared to the tunnel dimensions, the tendency to dilation across an increased number of non-planar joints may contribute to interlocking of blocks. The BB joint behavioural model which allows the modelling of the dilation accompanying shear and hence the build-up of higher normal stresses, predicts smaller deformations than the Mohr-Coulomb model in which the dilation angle is constant. The sensitivity studies involving changes in key BB joint shear strength parameters have shown that, within the range of values considered, the model output is relatively insensitive to assumed joint strength parameters joint roughness coefficient and (at. However, an increase in the joint wall compressive strength contributes to an increase in the joint shear strength resulting in a marked reduction of displacements around the opening.