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Shilpa Pal Amir M. Kaynia Rajinder K. Bhasin D. K. Paul 《Rock Mechanics and Rock Engineering》2012,45(2):205-215
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 m3. 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. 相似文献
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Dhananjay A. Sant Sudesh K. Wadhawan Rajinder K. Ganjoo Nathani Basavaiah Prabhin Sukumaran Sourabh Bhattacharya 《Journal of the Geological Society of India》2011,78(2):147-156
The paraglacial sequence in the Leh valley, Ladakh Himalaya preserves imprints of various processes active during deglaciation
in the late phase of Last Glacial. In present work, a high resolution sedimentological record generated for Spituk is presented
identifying aeolian episodes, mudflow events from Ladakh Range and debris flows extending from Zanskar Range across present
Indus River. Two temporal phases of water ponding within Spituk Sequence are also identified. The seismites recorded at various
stratigraphic depths and their association with the sediment facies signifies gravity induced process besides possible seismic
activity as an added phenomena. Linkage between paraglacial processes since Last Glacial to Recent is tracked and evaluated. 相似文献
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Paleo-uplift and cooling rates from various orogenic belts of India, as revealed by radiometric ages
The significant discordance of the radiometric (Rb-Sr, Pb-U, K-Ar and fission track) ages from various orogenic cycles of the Dharwar, Satpura, Aravalli and Himalayan orogenic belts in India, coupled with their corresponding blocking temperatures for various radiometric clocks in whole rocks and minerals, has been used to evaluate the cooling and the uplift histories of the respective orogenic belts. The blocking temperatures used in the present study of various Rb-Sr (isotopic homogenization at 600°C, muscovite at 500°C and biotite at 300°C), Pb-U (monazite at 530°C), K-Ar (muscovite at 350°C and biotite at 300°C) and fission-track clock (zircon at 350°C, sphene at 300°C, garnet at 280°C, muscovite at 130°C, hornblende at 120°C and apatite at 100°C for the cooling rate l°C/Ma) have been found suitable to explain the differences in mineral ages by different radiometric techniques. The nature of the cooling curves drawn using the temperature versus age data for various orogenic cycles in India has also been discussed. The cooling and the uplift patterns determined for various orogenic cycles of India, suggest comparatively slow cooling (5.0–0.2°C/Ma) and uplift (180–2 m/Ma) for the Peninsular regions and rapid cooling (25.0–1.0° C/Ma) and fast uplift (800–30 m/Ma) during the Himalayan Orogenic Cycle (Upper Cretaceous—Tertiary) in the Extra-Peninsular region. 相似文献
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In batch experiments for 6 to 48 h, individuals of Cyprinus carpio (2 g individual weight) were exposed to mixed solutions of copper and zinc sulphate: pH = 6.3, temperature 15 °C, 6.8 mg/l O2, 7.1 mg/l Ca2+, 0.7 mg/l Mg2+. The LC50 for the individual substances on exposures of 24 and 48 h amount to 9.04 and 7.28 mg/l, resp., of Zn and 0.11 and 0.095 mg/l, resp., of Cu. The sum of the biological activity of the two kinds of metal ions is assessed according to MARKING'S index: at low concentrations of the mixed solutions the two metals show an additive effect, at higher concentrations a synergistic effect occurs. 相似文献
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