Nepal highway alignment survey and aspects of integrated approach for route alignment study     

V. K. Jha  A. K. Roy  D. K. Jugran 《Journal of the Indian Society of Remote Sensing》1988,16(1):79-84

Satellite and aerial remote sensing techniques can provide useful, indicative information on most of the factors that are pertinent to a good route location. This information because it is obtained quickly, economically, and with fair to excellent dependability for large areas, can then be translated into better planning, design and constructions as well as lower maintenance cost. The Nepal highway project involved, besides study of geology, the mapping and delineation of land facets through which the route would pass, and included the study of (i) rock, (2) soil, (3) weathering, (4) slopes, (5) landslides, (6) hydrology and (7) construction material availability in an integrated manner. Remote sensing techniques helped in efficient selection of potential route than could have been possible by conventional ground techniques alone.  相似文献   

Reliability analysis of soil liquefaction based on standard penetration test   总被引：1，自引：0，他引：1  

Sanjay K. Jha  Kiichi Suzuki 《Computers and Geotechnics》2009

A review of probabilistic and deterministic liquefaction evaluation procedures reveals that there is a need for a comprehensive approach that accounts for different sources of uncertainty in liquefaction evaluations. For the same set of input parameters, different models provide different factors of safety and/or probabilities of liquefaction. To account for the different uncertainties, including both the model and measurement uncertainties, reliability analysis is necessary. This paper presents a review and comparative study of such reliability approaches that can be used to obtain the probability of liquefaction and the corresponding factor of safety. Using a simplified deterministic Seed method, this reliability analysis has been performed. The probability of liquefaction along with the corresponding factor of safety have been determined based on a first order second moment (FOSM) method, an advanced FOSM (Hasofer–Lind) reliability method, a point estimation method (PEM) and a Monte Carlo simulation (MCS) method. A combined method that uses both FOSM and PEM is presented and found to be simple and reliable for liquefaction analysis. Based on the FOSM reliability approach, the minimum safety factor value to be adopted for soil liquefaction analysis (depending on the variability of soil resistance, shear stress parameters and acceptable risk) has been studied and a new design safety factor based on a reliability approach is proposed.  相似文献   

Genotoxic, cytotoxic and developmental effects of tributyltin oxide (TBTO): an integrated approach to the evaluation of the relative sensitivities of two marine species.     

A N Jha  J A Hagger  S J Hill  M H Depledge 《Marine environmental research》2000,50(1-5):565-573

Adopting an integrated approach the potential genotoxic, cytotoxic and developmental effects of tributyltin oxide (TBTO), a known endocrine-disrupting agent for neogastropods, have been evaluated in two ecologically relevant invertebrates: Mytilus edulis (blue mussel) and Platynereis dumerilli (rag worm). Following determination of the maximum tolerated dose (MTD) in terms of developmental and survival effects, the embryo-larval stages of these organisms were exposed to a range of concentrations of TBTO, and analysed for cytotoxic (proliferation rate index) and genotoxic (sister chromatid exchanges and chromosomal aberrations) effects. The study suggested that: (1) TBTO is both toxic and genotoxic to embryo-larval stages of both species; (2) at comparable concentrations, for developmental and genotoxic effects, P. dumerilii (non-target species) is more sensitive compared to M. edulis (target species); and (3) genotoxic effects are more closely tied with the development and survival of the organisms. The study emphasises the need of the evaluation of genotoxic potential of other endocrine-disrupting agents in different taxonomic groups.  相似文献   

Effect of Nitrogen Management on Soil Microbial Community and Enzymatic Activities in Jatropha curcas L. Plantation          下载免费PDF全文

Doongar Ram Chaudhary  Ritesh Kumar Gautam  Arup Ghosh  Jitendra Chikara  Bhavanath Jha 《洁净——土壤、空气、水》2015,43(7):1058-1065

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Seasonal and Temporal Dynamics of Physicochemical and Biological Properties of Chronosequence Coal Mine Spoil Soils          下载免费PDF全文

Sufian A. Tapadar  Dhruva Kumar Jha 《洁净——土壤、空气、水》2016,44(10):1405-1413

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Unsteady forced and free-convection flow past an infinite vertical plate with constant heat flux     

Basant Kumar Jha 《Astrophysics and Space Science》1991,185(2):295-298

An analytical study is performed to examine the unsteady forced and free-convection flow of a viscous, incompressible fluid when there is a consdtant heat flux between fluid and plate. The expressions for the vleocity field, the penetration distance and the skin-friction have been obtained by the Laplace transform technique. The influence of the various parameters entering into the problem is extensively discussed with the help of tables.  相似文献   

Sedimentary effects on the expansion of a Himalayan supraglacial lake     

Kazuhisa Chikita  Jageshwar Jha  Tomomi Yamada 《Global and Planetary Change》2001,28(1-4)

Supraglacial Tsho Rolpa Lake in the Nepal Himalaya has been increasing rapidly in size since the 1950s, corresponding to the mountain-glacier shrinkage after the Little Ice Age. The lake basin expansion results from the subsidence by dead-ice melt below the bottom of the lake, and the retreat of the glacier terminus. Field observations of Tsho Rolpa in 1996 revealed that the retreat of glacier terminus is connected to a wind-induced vertical circulation of surface water heated by solar radiation. In order to clarify the mechanism of the lake expansion associated with sedimentary processes, we measured bottom sedimentation rate with some sediment traps, and vertical suspended sediment concentration (SSC) and water temperature, and analyzed the grain size of suspended and trapped sediments. The sediments, mostly composed of clay-sized grains, are dominantly supplied by glacier-melt water inflow at the glacier terminus. Sedimentary processes of such fine sediment comprise: (1) suspended-sediment fallout from intrusion of horizontal currents; (2) sediment sorting by sediment-laden underflows; and (3) the debris supply from the ice collapse at the glacier terminus. The (1) and (2) processes produce the density stratification of the lake, accompanied by a pycnocline at a depth of about 27 m. The existence of the pycnocline builds up the vertical water circulation in the surface layer to enhance the glacier-melt at the terminus. With respect to the subsidence of the lake bottom, nearly molecular thermal diffusion is probably dominant near the bottom of the deepest point, which results from the kinetic-energy dissipation of sediment-laden underflows. The stable existence of the bottom turbid water throughout the year could cause continuous dead-ice melt below the lake bottom.  相似文献   

    

P. K. Jha  P. Vaithiyanathan  V. Subramanian 《Environmental Geology》1993,22(1):13-20

Almost the entire suspended load of Yamuna River is transported during the monsoon period; quartz and illite are the dominant minerals of these suspended sediments. Basin lithology, tributary contributions, and sediment grain size seem to control mineral distribution in the sediments. Trace metal concentrations of Yamuna core sediments reflect their mineralogical composition. Illite is the chief clay mineral of the Himalayan river sediments. The mineralogical characteristics of the Himalayan river sediments differ significantly from the Peninsular Indian rivers, which chiefly carry montmorillonite.  相似文献   

Satellite image based quantification of invasion and patch dynamics of mesquite (Prosopis juliflora) in Great Rann of Kachchh,Kachchh Biosphere Reserve,Gujarat, India     

S Vazeed Pasha  K V Satish  C Sudhakar Reddy  P V V Prasada Rao  C S Jha 《Journal of Earth System Science》2014,123(7):1481-1490

The invasion of alien species is a significant threat to global biodiversity and the top driver of climate change. The present study was conducted in the Great Rann of Kachchh, part of Kachchh Biosphere Reserve, Gujarat, India, which has been severely affected by invasion of Prosopis juliflora. The invasive weed infestation has been identified using multi-temporal remote sensing datasets of 1977, 1990, 1999, 2005 and 2011. Spatial analyses of the transition matrix, extent of invasive colonies, patchiness, coalescence and rate of spread were carried out. During the study period of three and half decades, almost 295 km² of the natural land cover was converted into Prosopis cover. This study has shown an increment of 42.9% of area under Prosopis cover in the Great Rann of Kachchh, part of the Kachchh Biosphere Reserve during 1977 to 2011. Spatial analysis indicates high occupancy of Prosopis cover with most of the invasion (95.9%) occurring in the grasslands and only 4.1% in other land cover types. The process of Prosopis invasion shows high patch initiation, followed by coalescence, indicating aggressive colonization of species. The number of patches within an area of < 1 km² increased from 1977 to 2011, indicating the formation of new Prosopis habitats by replacing the grasslands. The largest patch of Prosopis cover increased from 144 km² in 1977 to 430 km² in 2011. The estimated mean patch size was 7.8 km² in 1977. The mean patch size was largest during 2011, i.e., 9 km². The annual spread rate for Prosopis has been estimated as 2.1% during 2005–2011. The present work has investigated the long term changes in Prosopis cover in the Great Rann of Kachchh, part of Kachchh Biosphere Reserve. The spatial database generated will be useful in preparing strategies for the management of Prosopis juliflora.  相似文献   

Numerical Simulation of Explosion in Twin Tunnel System     

A. K. Verma  Manish Kumar Jha  Srinivas Mantrala  T. G. Sitharam 《Geotechnical and Geological Engineering》2017,35(5):1953-1966

Rapid growth of urban population in Indian cities have led traffic congestion leading to demand for scientific utilization of underground space. Immediate underground level and deep level underground below the major arterial roads are the sustainable spaces available for meeting the demand of the future traffic/transport. Due to recent increased transit activities it has become one of the soft targets by terrorists or prone to catastrophic accidents in recent years which have increased the importance of rock structures study under explosive loading. In this paper, the response of a underground metro tunnel subjected dynamic loads have been investigated including explosive capacity (30 kg TNT), ground characteristics, liner thickness and blast pressure characteristics. Blast pressure representing CONWEP air blast loading model with positive over pressure phase was applied to lining of tunnel. A three dimensional explicit finite element method was used to analyze dynamic response and damage in twin tunnels of underground metro. It is found that liner of thickness 28 cm will start deforming at the explosive loading of more than 65 kg TNT.  相似文献