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11.
Probabilistic analyses provide rational means to treat the uncertainties associated with underlying parameters in a systematic
manner. The stability of a 734-m-high jointed rock slope in the west of Norway, the Oppstadhornet rock slope, is investigated
by using a probabilistic method. The first-order reliability method (FORM) is used for probabilistic modeling of the plane
failure problem in the rock slope. The Barton–Bandis (BB) shear strength criterion is used for the limit state equation. The
statistical distributions of the BB criterion parameters, for which comprehensive data were collected and statistically analyzed,
are determined by using distribution fitting algorithms. The sensitivity of the FORM model for the BB criterion is also investigated.
It is found that the model is most sensitive to the mean value of the residual friction angle (ϕ
r) and least sensitive to the mean value of the slope angle (β
f). It is also found that the standard deviation of joint compressive strength (JCS) causes the greatest difference in the
reliability index, which has the least sensitivity to the change in the mean and standard deviation of joint roughness coefficient
(JRC). 相似文献
12.
Manish Kumar Kalpana Kumari AL. Ramanathan Rajinder Saxena 《Environmental Geology》2007,53(3):553-574
Punjab is the most cultivated state in India with the highest consumption of fertilizers. Patiala and Muktsar districts are
two agricultural dominated districts of Punjab located in extreme south-east and south-west of the state. This paper highlights
temporal variations of the groundwater quality and compares its suitability for irrigation and drinking purpose in these two
districts. Water samples were collected in March and September 2003, representing the pre-monsoon and post-monsoon seasons,
respectively. Water samples were analysed for almost all major cations, anions, dissolved heavy metals and turbidity. Parameters
like sodium adsorption ratio, % sodium, residual sodium carbonate, total hardness, potential salinity, Kelley’s ratio, magnesium
ratio, index of base exchange and permeability index were calculated on the basis of chemical data. A questionnaire was also
used to investigate perception of villagers on taste and odour. Comparison of the concentration of the chemical constituents
with WHO (world health organization) drinking water standards of 2004 and various classifications show that present status
of groundwater in Patiala is better for irrigation and drinking purposes except for a few locations with a caution that it
may deteriorate in near future. In Muktsar, groundwater is not suitable for drinking. Higher total hardness (TH) and total
dissolved solids at numerous places indicate the unsuitability of groundwater for drinking and irrigation. Results obtained
in this forms baseline data for the utility of groundwater. In terms of monsoon impact, Patiala groundwater shows dilution
and flushing but Muktsar samples show excessive leaching of different chemical components into the groundwater leading to
the enrichment of different anions and cations indicating pollution from extraneous sources. No clear correlation between
the quality parameters studied here and perceived quality in terms of satisfactory taste response were obtained at electrical
conductivity values higher than the threshold minimum acceptable value. 相似文献
13.
Dhananjay A. Sant Sudesh K. Wadhawan Rajinder K. Ganjoo Nathani Basavaiah Prabhin Sukumaran Sourabh Bhattacharya 《Journal of the Geological Society of India》2011,77(6):499-510
In the present paper we study morphology, occurrence and mutual interrelationship of erosional (amphitheaters) and depositional
landforms belonging to glacial (moraines), fluvio-glacial (glacial out wash), mass wasting (alluvial fans), aeolian (obstacle
dune and sand sheets) and lacustrine (palaeo-lake sediments) processes within the Leh valley. These landforms are the geomorphic
expression of past deglaciation grouped into five Formative Stages of Landform (FSL 1 to FSL 5) development in the Leh valley.
The broad age bracket for the formative stages are based on the empirical relationship of the landforms, available chronology
and their correlation with comparable climate phases. The retreat of glaciers in the Leh valley, along the southern slopes
of Ladakh hill range and their retention over the northern slopes and Karakoram is further explained. 相似文献
14.
15.
In the daily exchange of the medium with only 7.1 mg/l Ca2+ and 0.7 mg/l Mg2+ during the batch experiment the LC50,96h for Cyprinus carpio is 0.063 mg/l Cu2+ and 3.12 mg/l Zn2+ at water temperatures of 11 to 14°C. Significant differences in mortality as referred to the LC50,12h occur for copper only after 72 h of exposure and for zinc after 48 h of exposure. The values of LC50,96h are clearly lower for both metals in the investigations described than most data given in literature for different fish species. 相似文献
16.
Fission track annealing characteristics of almandine-spessartine garnet have been investigated. The data indicate that the activation energy for thermal fading of tracks ranges from 2.6 to 6.0 eV with a mean of 4.1 eV. The annealing temperatures for this variety are lower than for the andradite-grossular variety. 相似文献
17.
Rajinder Parshad Snehmani Parveen Kumar P. K. Srivastva A. Ganju 《Journal of the Geological Society of India》2017,89(5):497-502
The attenuation properties have been estimated in the Nubra-Siachen region situated in the highly mountainous region of Himalayan belt. Coda wave quality factor (Qc) has been determined for this virgin region by using the single backscattering method. A total of thirty earthquakes recorded in this region, which fall in the epicentral distance range of 3 to 115km have been used for the present work. A 30 sec window length of coda waves at different central frequencies 1.5, 3.0, 6.0, 9.0, 12.0, 18.0 and 24.0 Hz have been studied to determine Qc at different recording stations. The frequency dependent coda wave quality factor relationships of the form Qc(f) = Qofn, have been computed at each recording stations separately: BASE: Qc(f) = (137 ± 4.2) f(0.99 ± 0.12), CHALUNKA: Qc(f) = (116±3.8)f(1.0±0.05), PARTA: Qc(f) = (122±3.0)f(1.0±0.02), and SASOMA: Qc(f) = (111±4.1)f(1.0±0.03). A regional Qc relation has been developed for the Nubra-Siachen region by using the average value of Qc at different frequencies obtained at each recording station of the form Qc(f) = (121±7.2)f(1.0±0.04). The average Qc values vary from 183 at 1.5 Hz to 3684 at 24 Hz central frequencies. The present regional relation developed for Nubra-Siachen region indicates heterogeneous and tectonically active region. 相似文献
18.
Rajinder Bhasin Eystein Grimstad Jan Otto Larsen Ashok K. Dhawan Rajbal Singh S. K. Verma K. Venkatachalam 《Engineering Geology》2002,64(4):351-368
Landslides and other mass movements are serious geo-environmental hazards in the Himalayas. Massive landslides killing tens of thousands of people with catastrophic damages have occurred in the Eastern Himalayan State of Sikkim, which shares common borders with Tibet, Nepal, and Bhutan. This paper describes the investigations carried out on recent landslides in Gangtok, Sikkim, India, with emphasis on the triggering mechanisms that have contributed to the release and creep of natural slopes in the region. It is believed that the intense rainfall in the region not only contributes to rapid erosion and weathering of the rock mass, but also increases the groundwater level that leads to reduction in the stability of natural slopes. A landslide instrumentation programme that includes placement of settlement pillars and piezometers is underway to predict the behaviour of landslides in the area. 相似文献
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20.
Rajinder Bhasin Nick Barton Eystein Grimstad Panayotis Chryssanthakis 《Engineering Geology》1995,40(3-4):169-193
A detailed engineering geological assessment of low strength (6–35 MPa) anisotropic rocks at an ongoing Hydroelectric Project in the Himalayan Region has been carried out. The project (the Nathpa Jhakri Hydroelectric Project) will have one of the world's largest and longest water conducting systems, consisting of a 10.15 m diameter and 27.3 km long head race tunnel, a 942 000 m3 underground desilting complex and a 20 × 49 × 216 m powerhouse cavern in the area. Because these constructions are made in low strength metamorphosed anisotropic rocks like quartz mica schists, biotite schists and muscovite schists, it seemed necessary and worthwhile to undertake a comprehensive study of such rocks. The studies include petrographic and petrofabric analyses of the rocks, geo-mechanical properties, rock stress measurements, rock mass classification using the Q-System and data concerning joint geometry, joint roughness and joint strength. The use of mapped geological and geotechnical data along with the experimental and modelling studies have helped to better understand the behaviour of these rocks in underground openings. 相似文献