Rock mass rating and Kinematic analysis for slope stability investigation of Utari dam,Lalitpur district,Uttar Pradesh     

M. E. A. Mondal  Tariq Siddique  Mohammad Alam  M. Masroor Alam 《Journal of the Geological Society of India》2016,87(4):463-468

Rock mass characterization of Utari dam in Lalitpur district of Uttar Pradesh was done to identify different stability classes of rock mass. For better stability of Utari dam, foundation conditions were carefully studied by detailed field investigations of the site supplemented by laboratory tests. During feasibility and preliminary stages, rock mass characterization of slopes was conducted to identify the vulnerable zones of failure. Rock mass characterization was done by compilation of information obtained from intact rock as well as from rock mass to determine its grade and long term slope stability of the site. On the basis of Rock Mass Rating (RMR) and Geological Strength Index (GSI) slope stability is identified which lies under good quality rock mass. Kinematic analysis was conducted to find out the probability for different types of structurally controlled slope failure. Microscopic analyses were conducted to identify the degree of chemical alteration of feldspar. Clay formation by sericitization along joint planes is harmful for the stability of dam structure. Remedial measures must be taken to reduce the extent of chemical alteration. Granitoids at dam site forms a compact and stable foundation consisting of four sets of joints in which two sets were prominent which are dipping on the upstream side of the dam which reveals good condition on the dam site as leakage from reservoir will be minimum and least up-thrust on the dam structure.  相似文献   

SMR geomechanics and kinematic analysis near Rasulpur,Fatehpur Sikri,Uttar Pradesh   总被引：1，自引：0，他引：1  

M. E. A. Mondal  Tariq Siddique  Bulbul Mondal  M. Masroor Alam 《Journal of the Geological Society of India》2016,87(5):623-627

Slope stability of mine slopes is often associated with safety and economics during excavation. Sandstone is excavated from Rasulpur area of Fatehpur Sikri in Uttar Pradesh for the purpose of crushed, decorative and dimension stones. In the present paper an attempt has been made to characterize the rock slope faces into different stability classes. Characterization is based on geological and geotechnical parameters recorded on the outcrop during field investigation and supplemented by geomechanical properties by the laboratory test for strength of the rock intact. SMR Geomechanics classification is used to identify the stability class and remedial measures are also suggested to reduce any possible hazard. Kinematic analysis of slope was also investigated to determine the probability of any possible structurally controlled failure. On the basis of SMR Geomechanics calculations slope under investigation lies under good stability class i.e. 2a and 2b. Installation of nets during excavation can be done and for better safety spot and systematic rock bolting can be done. Kinematic study reveals that toppling failures may occur, special care must be given to the joint set which can trigger toppling failure.  相似文献   

A methodology to determine thermal conductivity of soils from flux measurement     

Somenath Mondal  G.P. Padmakumar  V. Sharma  Maryam Shojaei Baghini 《Geomechanics and Geoengineering》2016,11(1):73-85

Determination of thermal properties of soils (viz., thermal resistivity, thermal conductivity, thermal diffusivity and heat capacity), which primarily influence heat migration through the soil mass, is essential in situations where geomaterials are relentlessly subjected to higher temperatures and temperature variations. These properties of the soil mainly depend upon its type, mineralogy, particle size and gradational characteristics, density and water content. In this context, earlier researchers have determined thermal conductivity of soils by employing a thermal probe (a line heat source), which works on the principle of transient method (TM) of heat conduction. However, this methodology cannot be employed for establishing the heat flow (read thermal regime) through the soil. Hence, development of an alternate technique, which facilitates quantification of temporal and spatial variation of the heat flux and temperature in the soil mass, becomes essential. With this in mind, a methodology to determine thermal conductivity of soils by employing the concept of thermal flux measurement (TFM) has been developed and its details are presented in this paper. Results obtained from the TM and TFM have also been critically evaluated for the sake of validation and generating more confidence in the proposed methodology.  相似文献   

Characterizing the 2D shape complexity dynamics of the islands of Sundarbans,Bangladesh: a fractal dimension approach     

Sugata Hazra  Anirban Mukhopadhyay  Abhra Chanda  Parimal Mondal  Tuhin Ghosh  Sandip Mukherjee  Mashfiqus Salehin 《Environmental Earth Sciences》2016,75(20):1367

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Integrating cellular automata and Markov techniques to generate urban development potential surface: a study on Kolkata agglomeration   总被引：1，自引：0，他引：1  

Biswajit Mondal  Dipendra Nath Das  Basudeb Bhatta 《国际地球制图》2017,32(4):401-419

Uncontrolled, yet fragmented peripheral urban expansion has emerged as a menace to urban development. To cope with this rapid urban expansion process, identification of the forces responsible for this rapid urban expansion is a pre-requisite, especially when its threats to habitability are taken into consideration. This study tries to evaluate fragmented uncontrolled urban expansion faced by Kolkata using cellular automata-Markov chain. Urban growth patterns, land use/land cover transformations and spatial allocation correspondence with planning strategy is the main theme of this study. Depending upon the driving forces, the study result indicates a bi-directional urban development potential surface, which might be a result of the biased planning initiative along with middle-class residential demand. This simulation result provides evidence for the planning authority to evaluate the effectiveness of spatial allocation and urban expansion trends and provide flexibility to modify the current allocation scenario.  相似文献   

Flood monitoring using microwave remote sensing in a part of Nuna river basin,Odisha, India     

Sananda Kundu  S. P. Aggarwal  Nanette Kingma  Arun Mondal  Deepak Khare 《Natural Hazards》2015,76(1):123-138

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Chemical characterization of wet precipitation events and deposition of pollutants in coal mining region,India     

Abhay Kumar Singh  G. C. Mondal 《Journal of Atmospheric Chemistry》2008,59(1):1-23

The present study investigated the chemical composition of wet atmospheric precipitation in India’s richest coal mining belt. Total 418 samples were collected on event basis at six sites from July to October in 2003 and May to October in 2004 and analysed for pH, EC, F⁻, Cl⁻, , , Ca²⁺, Mg²⁺, Na⁺, K⁺ and . The average pH value (5.7) of the rainwater of the investigated area is alkaline in nature. However, the temporal pH variation showed the alkaline nature during the early phase of monsoonal rainfall but it trends towards acidic during the late and high rainfall periods. The rainwater chemistry of the region showed high contribution of Ca²⁺ (47%) and (21%) in cations and (55%) and Cl⁻ (23%) in anionic abundance. The high non seas salt fraction (nss) of Ca²⁺ (99%) and Mg²⁺ (96%) suggests crustal source of the ions, while the high nss (96%) and high ratio signifying the impact of anthropogenic sources and the source of the acidity. The ratio of varies from 0.03 to 3.23 with the average value of 0.84 suggesting that Ca²⁺ and play a major role in neutralization processes. The assessment of the wet ionic deposition rates shows no any specific trend, however Ca²⁺ deposition rate was highest followed by and _.  相似文献   

Compositional variations in the Mesoarchean chromites of the Nuggihalli schist belt, Western Dharwar Craton (India): potential parental melts and implications for tectonic setting     

Ria Mukherjee  Sisir K. Mondal  Minik T. Rosing  Robert Frei 《Contributions to Mineralogy and Petrology》2010,160(6):865-885

The chromite deposits in the Archean Nuggihalli schist belt are part of a layered ultramafic–mafic sequence within the Western Dharwar Craton of the Indian shield. The 3.1-Ga ultramafic–mafic units occur as sill-like intrusions within the volcano-sedimentary sequences of the Nuggihalli greenstone belt that are surrounded by the tonalite–trondhjemite–granodiorite (TTG) suite of rocks. The entire succession is exposed in the Tagdur mining district. The succession has been divided into the lower and the upper ultramafic units, separated by a middle gabbro unit. The ultramafic units comprise of deformed massive chromitite bodies that are hosted within chromite-bearing serpentinites. The chromitite bodies occur in the form of pods and elongated lenses (~60–500 m by ~15 m). Detailed electron microprobe studies reveal intense compositional variability of the chromite grains in silicate-rich chromitite (~50% modal chromite) and serpentinite (~2% modal chromite) throughout the entire ultramafic sequence. However, the primary composition of chromite is preserved in the massive chromitites (~60–75% modal chromite) from the Byrapur and the Bhaktarhalli mining district of the Nuggihalli schist belt. These are characterized by high Cr-ratios (Cr/(Cr + Al) = 0.78–0.86) and moderate Mg-ratios (Mg/(Mg + Fe²⁺) = 0.38–0.58). The compositional variability occurs due to sub-solidus re-equilibration in the accessory chromite in the serpentinite (Mg-ratio = 0.01–0.38; Cr-ratio = 0.02–0.99) and in silicate-rich chromitite (Mg-ratio = 0.06–0.48; Cr-ratio = 0.60–0.99). In the massive chromitites, the sub-solidus re-equilibration for chromite is less or absent. However, the re-equilibration is prominent in the co-existing interstitial and included olivine (Fo_96–98) and pyroxene grains (Mg-numbers = 97–99). Compositional variability on the scale of a single chromite grain occurs in the form of zoning, and it is common in the accessory chromite grains in serpentinite and in the altered grains in chromitite. In the zoned grains, the composition of the core is modified and the rim is ferritchromit. In general, ferritchromit occurs as irregular patches along the grain boundaries and fractures of the zoned grains. In this case, ferritchromit formation is not very extensive. This indicates a secondary low temperature hydrothermal origin of ferritchromit during serpentinization. In some occurrences, the ferritchromit rim is very well developed, and only a small relict core appears to remain in the chromite grain. However, complete alteration of the chromite grains to ferritchromit without any remnant core is also present. The regular, well-developed and continuous occurrence of ferritchromit rims around the chromite grain boundaries, the complete alteration of the chromite grains and the modification of the core composition indicate the alteration in the Nuggihalli schist belt to be intense, pervasive and affected by later low-grade metamorphism. The primary composition of chromite has been used to compute the nature of the parental melt. The parental melt calculations indicate derivation from a high-Mg komatiitic basalt that is similar to the composition of the komatiitic rocks reported from the greenstone sequences of the Western Dharwar Craton. Tectonic discrimination diagrams using the primary composition of chromites indicate a supra-subduction zone setting (SSZ) for the Archean chromitites of Nuggihalli and derivation from a boninitic magma. The composition of the komatiitic basalts resembles those of boninites that occur in subduction zones and back-arc rift settings. Formation of the massive chromitites in Nuggihalli may be due to magma mixing process involving hydrous high-Mg magmas or may be related to intrusions of chromite crystal laden magma; however, there is little scope to test these models because the host rocks are highly altered, serpentinized and deformed. The present configurations of the chromitite bodies are related to the multistage deformation processes that are common in Archean greenstone belts.  相似文献   

Assessment of groundwater pollution due to tannery industries in and around Dindigul, Tamilnadu, India     

N. C. Mondal  V. K. Saxena  V. S. Singh 《Environmental Geology》2005,48(2):149-157

The overexploitation of groundwater in some parts of the country induces water quality degradation. The untreated industrial effluents discharged on the surface causes severe groundwater pollution in the industrial belt of the country. This poses a problem of supply of hazard free drinking water in the rural parts of the country. There are about 80 tanneries operating in and around Dindigul town in upper Kodaganar river basin, Tamilnadu, India. The untreated effluents from the tanneries have considerably affected the quality of groundwater in this area. To assess the extent of groundwater deterioration, a detailed analysis of groundwater quality data has been carried out. The concentration of cations such as Calcium (Ca²⁺), Magnesium (Mg²⁺), Sodium (Na⁺) and Potassium (K⁺), and anions such as Bicarbonate (HCO₃^–), Sulphate (SO₄^2–), Chloride (Cl^–) and Nitrate (NO₃^–) in the groundwater have been studied. Apart from these constituents, pH, electrical conductivity (EC), total dissolved solid and total hardness (TH as CaCO₃) were also studied. The correlation of these constituents with the EC has been carried out. The highest correlation is observed between EC and chloride with a correlation coefficient of 0.99. Progressive reduction in correlation coefficients for Mg²⁺, (Na⁺ + K⁺), Ca²⁺ and SO₄^2– are observed as 0.91, 0.87, 0.86 and 0.56, respectively. It is found that the quality of groundwater in the area under investigation is deteriorated mainly due to extensive use of salt in the leather industries.  相似文献   

Hydrochemistry of reservoirs of Damodar River basin, India: weathering processes and water quality assessment     

Abhay Kumar Singh  G. C. Mondal  P. K. Singh  S. Singh  T. B. Singh  B. K. Tewary 《Environmental Geology》2005,48(8):1014-1028

Water samples collected from the six reservoirs of Damodar River basin in pre- and post-monsoon, have been analysed, to study the major ion chemistry and the weathering and geochemical processes controlling the water composition. Ca, Na and HCO₃ dominate the chemical composition of the reservoir water. The seasonal data shows a minimum concentration of most of the ions in post-monsoon and a maximum concentration in pre-monsoon seasons, reflecting the concentrating effects due to elevated temperature and increased evaporation during the low water level period of the pre-monsoon season. Water chemistry of the reservoirs strongly reflects the dominance of continental weathering aided by atmospheric and anthropogenic activities in the catchment area. Higher concentration of SO₄ and TDS in Panchet, Durgapur and Tenughat reservoirs indicate mining and anthropogenic impact on water quality. The high contribution of (Ca+Mg) to the total cations, high concentration of dissolved silica, relatively high (Na+K)/TZ⁺ ratio (0.3) and low equivalent ratio of (Ca+Mg)/(Na+K) suggests combined influence of carbonate and silicate weathering. Kaolinite is the possible mineral that is in equilibrium with the water, implying that the chemistry of reservoir water favours kaolinite formation. The calculated values of SAR, RSC and sodium percentage indicate the ‘excellent to good quality’ of water for irrigation uses.  相似文献