Papers by Rameshwar Sangra
Journal of Palaeosciences, Dec 31, 2019
Northwest Himalaya has witnessed lot of mass movements during the Quaternary period which have le... more Northwest Himalaya has witnessed lot of mass movements during the Quaternary period which have led to palaeoenvironmental degradation and deposition of erratic size sediments. These sediments have developed as fossil slides along the mountain slopes. In last few decades, the frequency of landslides has increased due to various factors such as complex geology, geotechnical properties of the rocks and anthropogenic activities. The investigation of rock slopes require geo-engineering evaluation to assess the instability of critical slopes leading to landslides particularly in the Himalayan region, where rocks are highly folded, faulted, jointed and weathered. In the present study, a total of 15 rock slopes have been selected for rapid assessment of instability condition using rock mass rating basic (RMRb), slope mass rating (SMR) and kinematics analysis techniques along Bhaderwah-Bani Highway in Jammu and Kashmir. Field surveys were conducted regarding required input data collection followed by laboratory works. The results of RMRb show two classes of rock mass, i.e., Class II-Good (86.58%) and Class III-Fair (13.42%). The SMR index classify rock slopes into different stability class results, which infers completely unstable (L4 and L14), unstable (L1, L2, L3, L8, L9, L11, L12 and L13), partially stable (L5, L6 and L7) and stable (L10 and L15) categories. The final output of kinematic analysis verify different modes of structurally controlled slope failures i.e., planar (30.72%), wedge (57.6%) and toppling (11.52%), representing all 15 sites in the study area.
Journal of the Geological Society of India, 2022
The present study aims at evaluating the morphometric parameters of Baner, Neogal and Awa river b... more The present study aims at evaluating the morphometric parameters of Baner, Neogal and Awa river basins in Himachal Pradesh, India for making important assessments about the morphometric characteristics and geo-hydrological conditions of these watersheds. Georeferenced Survey of India toposheets, Cartosat-DEM are the datasets used in ArcGIS software for the delineation of watersheds and calculating important morphometric parameters along with the preparation of relief, slope, aspect and drainage basin asymmetry maps. The results show that the Neogal and Awa rivers are of 6 th order whereas Baner river is of 7 th order. The basins are of elongated shape and the drainage is mainly of sub-dendritic to dendritic type. In the northern regions of these river basins, the slopes are very steep and the relief is very high that results in rapid runoff and increases the intensity of erosion. High drainage density (>2.8) and fine drainage texture (>9) indicate moderately permeable subsurface material that causes groundwater deficit. These watersheds have developed asymmetrical drainage and their high ruggedness values (>12) refers to the rejuvenated stage of their geomorphic development. The study concludes that erosion-prone areas with rapid runoff are present in the area and adequate measures will assist in the sustainable management of land and water resources.
Journal of the Geological Society of India, 2017
In this paper, the results of geotechnical investigations on the slope stability condition carrie... more In this paper, the results of geotechnical investigations on the slope stability condition carried along the historical Mughal road (an important economic corridor of the state) from Bafliaz (Jammu province) to Shopian (Kashmir province) linking NH144 and NH444 respectively is presented. The basic rock mass rating (RMRb), slope mass rating (SMR) techniques (both discrete and continuous functions) with kinematics analysis was applied to analyse the rock mass and slope conditions at 20 selected sites. The RMRb results obtained reveal the slopes can be categorized into very good (5%), good (55%) and fair (40%) whereas SMR results reveal that the slopes are partially stable (50%), unstable (30%) and completely unstable (20%) with probable planar failure mode (20%), toppling failure mode (27%) and wedge failure mode (53%). The discrete and continuous SMR index reveals maximum variation in the end results within an average difference of 4.7 ±6. The kinematic analysis results support inter dependency of RMRb, SMR and critical joint-slope orientation relationships.
Journal of the Geological Society of India, 2019
Dambu and Saraks slide are the two prominent translational debris slides along the national highw... more Dambu and Saraks slide are the two prominent translational debris slides along the national highway 1-A, which disrupts the vehicular traffic along this route. Detailed geotechnical investigation of soil samples from these landslides have been carried out to determine inherent cause of instability. Further finite element analysis (FEA) for the landslides was carried out to determine the strength reduction factor of the slope material for finding the critical slope failure point and total displacements. Results indicate the FOS of 1.95 for Dambu slide and 0.47 for Saraks slide respectively. The results of the geotechnical lab investigations for both the landslides are conformable with the FEA and the field observations.
Environmental Earth Sciences, 2018
Landslides are the most established geological hazards in the frontal fold-thrust belt of Northwe... more Landslides are the most established geological hazards in the frontal fold-thrust belt of Northwestern Himalaya comprising of Siwaliks and Murree strata. The continuous rainfall from 2 to 6 September, 2014 caused a massive landslide at village Sadal in Udhampur district of Jammu and Kashmir state. The landslide occurred in the early morning of September 6, 2014, destroying entire Sadal habitation comprising 45 houses, and killing 41 people and more than 500 domestic animals. Google earth images of pre and post-landslide events along with the field measurements show the kinematics of upper and lower parts of the slide. Horizontal and vertical components of displacement and mode of failure suggest the landslide as of complex nature. The shallow subsurface geophysical imaging through Ground Penetrating Radar (GPR) survey shows the failure plane composed of friable mudstone bed underlain by massive mudstone and overlain by cross-bedded sandstone. The depth of debris material above the failure plane ranges from 6 m at Site S1a-b to 10 m at Site-S2b and 20 m at Site S3a. The velocity analysis of Site-3 shows four thick layers represented from bottom to surface by L1-sandstone (V = 0.16 m/ ns, travel time = 356.36 ns), L2-mudstone (V = 0.17 m/ns, travel time = 288.48 ns), L3-massive mudstone (V = 0.19 m/ ns, travel time 220.68 ns), and L4-cross-laminated sandstone (V = 0.20 m/ns, travel time = 77.58 ns) overlaying the failure plane. The study shows the landslide occur along the western limb of a fold identified during the present work. We mapped an old landslide on the same limb which shows 5-6 m-thick subsurface debris material with thick rock fragments involved in the landslide process. The detailed geological and geophysical investigations suggest that both the landslides were triggered by extreme rain fall events.
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Papers by Rameshwar Sangra