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Renato Macciotta C. Derek Martin Tom Edwards David M. Cruden Tim Keegan 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2015,9(3):171-186
Relationships between weather conditions and rock fall occurrences have been acknowledged in the past, but seldom have such relationships been quantified and published. Rock falls are frequent hazards along transportation corridors through mountainous terrain, and predicting hazardous rock fall periods based on weather conditions can enhance mitigation approaches. We investigate the relationship between weather conditions and rock fall occurrences along a railway section through the Canadian Cordillera. Monthly weather-rock fall trends suggest that the seasonal variation in rock fall frequency is associated with cycles of freezing and thawing during the winter months. The intensity of precipitation and freeze–thaw cycles for different time-windows was then compared against recorded rock falls on a case-by-case approach. We found that periods when 90% of rock falls occurred could be predicted by the 3-day antecedent precipitation and freeze–thaw cycles. Some rock falls not predicted by this 3-day antecedent approach occurred during the first two weeks of spring thaw. These findings are used to propose a rock fall hazard chart, based on readily available weather data, to aid railway operators in their decision-making regarding safe operations. 相似文献
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A new gravimetric geoid model for Sudan using the KTH method 总被引:2,自引:0,他引:2
225.
Expected damage from displacement of slow-moving slides 总被引:10,自引:7,他引:3
Facilities such as buildings, highways, railways, bridges, dams and pipelines often are built on natural slopes where the
risk of landslides is not low. The vulnerability of these facilities to slow-moving slides has sometimes been underestimated,
although the velocity of some classes of slow slides is uncontrollable. More than 50 cases of slow slides were compiled from
the literature for this study. Some statistics about the movement trigger(s), the methods used to measure displacement, the
material forming the rupture surface and the type of the vulnerable facilities are presented. It is shown that the expected
degree of damage to urban settlements, highways, bridges and dams can be related to the slide velocity or accumulating displacement.
Buildings and residential houses may tolerate higher slide velocities and total displacements than other facilities before
experiencing serious damage. Movements as low as 100 mm may severely damage bridges, but such low rates may cause only moderate
damage to urban communities. The relationship between movement and the expected extent of damage should be useful to geotechnical
engineers who deal with different classes of slow slides and will help in the choice of appropriate mitigation measures based
on preliminary estimates of movement rates. 相似文献
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Laurence Laperrière Marie-Andrée Fallu Sonja Hausmann Reinhard Pienitz Derek Muir 《Journal of Paleolimnology》2008,40(1):309-324
Qualitative and quantitative analysis of fossil diatoms and geochemical signals preserved in the sediments of Lac Dauriat
(subarctic Quebec) were performed to evaluate the impacts of nearby mining activity and the expansion of the town of Schefferville
on the water quality of the lake, and to reconstruct the changes of its trophic status. The presence of taxa typical of nutrient-enriched
environments (e.g., Cyclostephanos invisitatus, Nitzschia gracilis, Nitzschia perminuta) and the low percentages of chrysophytes were indicative of the advanced state of eutrophication of the lake during the peak
of mining activity, and were evidence of the negative impacts of municipal waste on the water quality of Lac Dauriat. Sedimentary
analysis of metals, notably lead, mercury, cadmium, bismuth, cobalt, copper and zinc, showed maximum concentrations between
1940 and 1960 with mining era to pre-development enrichment factors ranging from 4.5 to 7.9. The changes seen in recent sediments
reflected 3 distinct stages in the recent history of this ecosystem: (a) the non-perturbed, pre-mining (1882–1939), (b) the
perturbed, mining period (1939–1977) with accelerated eutrophication, and (c) the post-mining period (1977–1999) with indications
of natural recovery of the system after the installation of a water treatment plant in 1975, the closing of the mine in 1983,
and the subsequent exodus of the town’s population. Despite the trajectory towards a return to the lake’s natural conditions,
water resource managers and (paleo-)limnologists should be alarmed that the impacts of past human disturbance are still in
evidence more than 20 years after the closure of the mines, and that Lac Dauriat has yet to reach its natural state of the
period preceding extreme anthropogenic impact. 相似文献
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