Overcoming source limitations in drainage delineation by combining the streams of toposheet and DEM in river morphometric studies     

Rajesh Kumar Sah  Apurba Kumar Das 《Journal of the Geological Society of India》2017,89(2):183-191

A potential head ward retreat landslide area was identified in Munnar, a hill station in Western Ghats of Kerala, India. This imminent landslide was suspected to be formed in three different stages viz., evolution of plateau region, upliftment of the plateau region and the consequent slope modification which ultimately facilitated landslide occurrence. Geophysical study through vertical electrical sounding reveals that more than 11 m thick soil is still left in an overhanging position in the crown portion of the landslide and the thickness continues to the top of that ridge. In the event of high rainfall, the land can fail as there is no toe support, and the slope angle is >40º. This area is adjacent to a college building and in the event of any further landslide, the consequence will be high. Slope stability analysis using one-dimensional infinite slope stability model reveals that the entire area occupied by the college and the adjacent areas are unstable even in dry conditions. Rainfall threshold analysis shows that the landslide occurred due to very high amount of a 5-day antecedent rainfall rather than a daily rainfall during the monsoon. All these point towards a pressing requirement of landslide management practices in this area. This study also attempts to suggest a few management practices to minimize the effect of landslides.  相似文献   

Assessment of Durability and Weathering State of Some Igneous and Metamorphic Rocks Using Micropetrographic Index and Rock Durability Indicators: A Case Study     

M. Ahmad  M. K. Ansari  Rajesh Singh  L. K. Sharma  T. N. Singh 《Geotechnical and Geological Engineering》2017,35(2):827-842

Weathering and durability are the key factors of the rock in the suitability and usefulness of different construction materials, building materials and engineering structures. A single test never predicts the entire factor for suitability of rock stone and aggregate in different uses. Thus, variety of physical, mechanical and chemical tests and indices of rocks are widely used to estimate and evaluate the rocks for the suitability of the required purpose. In all the cases, knowledge of durability and weathering properties are the most important along with the strength of the rock. Micropetrographic index and rock durability indicators (dynamic and static) are the one of the best methods to evaluate the rock for weathering and durability. To estimate these indices, variety of tests are performed such as petrographic examination test, point load index, sulfate soundness test, water absorption test, modified aggregate impact value test and test for specific gravity. Slake durability index and impact strength index tests were also performed for correlation with static and dynamic rock durability indicators due to its application and usefulness in the durability and strength of the rock materials. Micropetrographic index was obtained by petrographic examination test and correlated with all the physical and mechanical properties used for find out the durability indicators. The present study is to express the usefulness of these three indices in the classification of weathering and durability classes and estimation of durability indices by slake durability index, impact strength index and micropetrographic index.  相似文献   

Free convection along a vertical wall in a porous medium with periodic permeability variation     

P. Singh  J. K. Misra  K. A. Narayan 《国际地质力学数值与分析法杂志》1989,13(4):443-450

This communication investigates the effect of permeability variation on free convection flow and heat transfer in a porous medium bounded by a vertical porous wall. A transverse periodic variation in permeability is considered to study the effect on heat transfer rate and skin friction. The problem becomes three-dimensional due to the variation in permeability. Analytical expressions for velocity, temperature, skin friction and rate of heat transfer are obtained using the perturbation technique. Effects of permeability and suction parameters on skin friction and heat transfer is studied and it is found that the increase in permeability creates a higher heat transfer rate and greater skin friction. However, the increase in suction parameter causes the skin friction values to decrease. The results obtained will be useful in the design of steam displacement processes in oil recovery and various geothermal systems.  相似文献   

An Experimental Study of the Effect of Temperature and Stress on the Creep of Rocks     

A. K. Misra  S. A. F. Murrell 《Geophysical Journal International》1965,9(5):509-535

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Land use — land cover mapping using satellite data for a forested watershed, Udupi district, Karnataka state, India     

Amba Shetty  Lakshman Nandagiri  Sangeeta Thokchom  M. V. S. Rajesh 《Journal of the Indian Society of Remote Sensing》2005,33(2):233-238

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Village level crop inventory using remote sensing and field survey data     

R. P. Singh  V. N. Sridhar  V. K. Dadhwal  R. Jaishankar  M. Neelkanthan  A. K. Srivastava  G. D. Bairagi  N. K. Sharma  S. A. Raza  Rajesh Sharma  Manoj Yadav  F. K. Joshi  N. L. Purohit 《Journal of the Indian Society of Remote Sensing》2005,33(1):93-98

This paper presents results of a pilot study in six villages located in the states of Haryana, Rajasthan and Madhya Pradesh, to evaluate accuracy of crop area at village level estimated by IRS - LISS-I1I data with respect to detailed field survey carried out by National Sample Survey Organization. The selected villages were located in Karnal, Kota and Bhopal districts which represented single dominant wheat crop as well as wheat-mustard and wheat-gram situation, respectively. Accuracy assessment of remote sensing based estimate with field survey of NSSO showed relative deviation in wheat estimate ranging from 3.72 percent for Mainmati village in Karnal district in Haryana to 22.65 percent fo Ranpur village in Kota district of Rajasthan. It was found that relative deviation in area estimation is inversely poportional to the crop proportion in that village. Observations of over estimation at low crop proportion and underestimation at higher crop proportion was explained by simple budgeting of relative proportion of ommision and commision errors. The study demonstrates that on the average, 90 percent crop area accuracy is possible with LISS-II1 data and the adopted approach.  相似文献   

Proposed river-linking project of India: a boon or bane to nature     

Anil Kumar Misra  Anju Saxena  Manish Yaduvanshi  Ajai Mishra  Yogendra Bhadauriya  Alok Thakur 《Environmental Geology》2007,51(8):1361-1376

India is a vast country and is highly diversified in terms of natural resources and socio-economic setup. Moreover, its water resources are unevenly distributed in space and time. With increasing population and increasing aspiration for improved standard of living, there is an acute pressure on the demand and availability of water. Though the idea of interlinking of rivers is not a new concept in India, it had rather persisted long back as much as in other countries of ancient civilization. National Water Development Agency (NWDA) has given the real shape to the proposal of the interlinking of rivers of the country. In India the river-linking project in a sensible and scientific manner will not only allow the prevention of the colossal wastage of a vitally important natural resource, mitigate the flood and inundation by detaining flowing surface water of rainy seasons, but also ensure availability of water to drier areas; combating both flood and drought simultaneously. Moreover, this project will generate 34,000 MW of hydropower and irrigation of an additional 35 million hectares (135,135 square miles) of land. Though linking of rivers may initially appear to be a costly proposition in ecological, geological, hydrological and economical terms, in the long run the net benefits coming from it will far outweigh these costs or losses. However, in the absence of any definite international legal framework, Bangladesh has raised objections against the project. This paper aims at looking at this long-term plan, the project proposal, its involvement and impact not only on the states of India, India as a whole, but also on its neighbouring nations which are linked with India through the waterways, and share the common climatic conditions and economic status.  相似文献   

Is the outcrop topology of dolerite dikes of the Precambrian Singhbhum Craton fractal?     

Nibir Mandal  Atin Kumar Mitra  Santanu Misra  Chandan Chakraborty 《Journal of Earth System Science》2006,115(6):643-660

In the Precambrian Singhbhum Craton of eastern India, newer dolerite dikes occur profusely with varying outcrop lengths. We have analysed the nature of their length-size and orientation distributions in relation to the theory of fractals. Two orientational sets of dikes (NW-SE and NE-SW) are present. Both the sets show strongly non-power-law size distributions, as reflected in non-linear variations in logarithmic space. We analyzed thousands of data, revealing that polynomial functions with a degree of 3 to 4 are the best representatives of the non-linear variations. Orientation analysis shows that the degree of dispersions from the mean trend tends to decrease with increasing dike length. The length-size distributions were studied by simulating fractures in physical models. Experimental fractures also show a non-power-law distribution, which grossly conforms to those of the dolerite dikes. This type of complex size distributions results from the combined effects of nucleation, propagation and coalescence of fractures.  相似文献   

Reply to discussion on “Age of granitic activity associated with copper–molybdenum mineralization at Malanjkhand, central India” by Holly Stein, Judith Hannah, Aaron Zimmerman, and Richard Markey     

Mruganka K. Panigrahi  Brendan R. Bream  Kula C. Misra  Rajesh K. Naik 《Mineralium Deposita》2006,40(6-7):766-768

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Axial service limit state analysis of drilled shafts using probabilistic approach     

Anil Misra  Lance A. Roberts 《Geotechnical and Geological Engineering》2006,24(6):1561-1580

Drilled shafts are, typically, designed by considering the axial ultimate limit state. In this design methodology, the axial displacement requirements are verified once the design is completed. As an alternative, drilled shafts may be designed by considering the axial service limit state. Service limit state foundation design is more efficient when done using the load and resistance factor design (LRFD) approach. Furthermore, reliability may be rationally incorporated into the design process that utilizes the LRFD method. In this paper, we develop probabilistic approaches for axial service limit state analysis of drilled shafts. The variability of shaft-soil interface properties is modeled by lognormal probability distribution functions. The probability distributions are combined with a closed-form analytical relationship of axial load-displacement curves for drilled shafts. The closed-form analytical relationship is derived based upon the “t–z” approach. This analytical relationship is used with the Monte Carlo simulation method to obtain probabilistic load-displacement curves, which are analyzed to develop methods for determining the probability of drilled shaft failure at the service limit state. The developed method may be utilized to obtain resistance factors that can be applied to LRFD based service limit state design.  相似文献