Identification of soil degradation during earthquake excitations by Bayesian inference     

Jianye Ching  Steven D. Glaser 《地震工程与结构动力学》2003,32(6):845-869

A Bayesian inference approach is introduced to identify soil degradation behaviours at four downhole array sites. The approach of inference is based on a parametric time‐varying infinite impulse response filter model. The approach is shown to be adaptive to the changes of filter parameters and noise amplitudes. Four sites, including the Lotung (Taiwan), Chiba (Japan), Garner Valley (California), and Treasure Island (California) sites with downhole seismic arrays are analysed. Our results show two major types of soil degradation behaviour: the well‐known strain‐dependent softening, and reduction in stiffness that is not instantaneously recoverable. It is also found that both types of soil degradation are more pronounced in sandy soils than in clayey soils. The mechanism for the second type of soil degradation is not yet clear to the authors and suggested to be further studied. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

铁路碎石道碴层导热系数测试研究   总被引：13，自引：3，他引：13  

张建明  盛煜  赖远明 《冰川冻土》2003,25(6):628-631

采用稳态比较法，对铁路碎石道碴层的导热系数进行了测试．试验在常温条件下，分别对底部加热及顶部加热两种情况进行了研究．结果表明：当碎石道碴层顶、底面之间的温差较小时，顶部加热及底部加热两种试验条件下测得的导热系数基本相同；而当碎石道碴层顶、底面温差较大时，底部加热条件下的导热系数明显地大于顶部加热条件下的导热系数．在底部加热条件下，碎石道碴层的导热系数随温差的增大而逐渐增大．碎石道碴层具有吸热和放热条件下传热的不对称性，合理地利用碎石道碴层的这一传热特性，可望对路基下多年冻土起到积极的保护作用。  相似文献   

LAND DEGRADATION AND ITS MANAGEMENT IN THE ARID AND SEMI ARID AREAS OF CHINA     

Leng Shuying Zheng Du Institute of Geography  CAS  Beijing People''s Republic of China 《地理学报(英文版)》1997,(4)

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Shorelines of the Uppsala Esker East-Central Sweden: Their Use as Indicators of Regional Differences in Shore Displacement     

Lars-Erik &#;se 《Geografiska Annaler: Series A, Physical Geography》1997,79(1-2):67-81

About 750 different shoremarks, mainly shore terraces, have been levelled along the Uppsala esker. Using various methods it has been possible to arrange the shoremarks to shorelines or rather shoremark zones containing more shoremarks than intervening parts. The material was divided into two major parts, i.e. shoremarks below c . 15 m above sea level and shoremarks above c . 15 m. It was found that shorelines on the whole were sloping towards the north. This was expected because of the faster shore displacement in the northern part of the area. However, the shorelines below c . 15 m a.s.l. indicated a slower increase in shore displacement than those of higher altitudes. A conclusion drawn from this might be that the increase towards the north is retarded in the area around Lake Mälar. This result is in reasonable agreement with recent isobase systems constructed from the evidence of mareograph records and repeated precise levellings. On the other hand, the shoreline studies give evidence of more pronounced regional differences in shore displacement in earlier Litorina times than those found today.  相似文献   

The Sahelian desertification debate: a view from the American south-west     

Charles F. Hutchinson 《Journal of Arid Environments》1996,33(4):519-524

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具有经济性前景的粗岩屑堆天然冷能集聚分析     

Aldar P. Gorbunov 《冰川冻土》2004,26(Z1):197-200

The coarse-detrital deposits have the properties of cold accumulation and maintenance of cold for a long time. Now, at some place where the mean annual temperature of air is positive, one even can get the permafrost by artificial formation of the burial mound. According to these properties, some lowenergy storehouses are built for various purposes.  相似文献   

多年冻土地区建筑物地基的热稳定性技术   总被引：1，自引：0，他引：1  

Refik M. Bayasan  Anatoly G. Korotchenko 《冰川冻土》2004,26(Z1):201-205

Thermal stabilization of soils (including freezing of thawed soils and cooling of permafrost) is known to be the effective method providing stable support for buildings and structures in cold regions.Seasonal thermo-stabilizers (STS) are mainly used in construction. The predicted climate warming because of natural and man-caused factors determines wide application of STS in permafrost regions. A STS transfers heat from its underground part (evaporator) to the aerial part (condenser) owing to natural temperature difference between them during a cold season. We have been working out and manufacturing different types of two-phase, vapor-liquid STS. Aluminum alloys are used in our STS to prevent corrosion and to increase their efficiency. They are successfully used in the northern regions of Western Siberia, in particular, at the railway Obskaya Bovanenkovo. The paper presents some technical parameters of new STS, the results of their experimental study and computer simulation, as well as experience features.  相似文献   

多年冻土区路桥过渡段的一种新结构     

刘建坤  鲍维猛  黎明  葛建军 《冰川冻土》2004,26(Z1):210-214

The design of roadbed-abutment transition part is always a challenging problem in transportation engineering, especially in permafrost distribution zone. A new type of roadbed-abutment transition part on permafrost was presented, and long-term observation was conducted for the deformation and the thermal regime of a roadbed-abutment transition part in the constructing Qinghai-Tibet Railway. In this paper, a new structure was presented and the observed settlements both in the subgrade and the base and its dependency with the thermal regime (permafrost table) were analyzed. In conclusion the roadbed-a-butment transition method for permafrost distribution zone was evaluated.  相似文献   

多年冻土地区金刚石矿的环境问题--以Yakutia 西北部Anabar矿为例   总被引：1，自引：0，他引：1  

V.N. Makarov 《冰川冻土》2004,26(Z1):257-262

Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the placers, as well as the poor assimilative capacity of the natural systems can result in serious environmental impacts in the area. The primary geochemical processes in the diamond-bearing area are affected by the occurrence of permafrost and relict ice, the lengthy duration of ice cover in water bodies, and the widespread development of cryogenic processes. This promotes physical migration of contaminants, cryogenic metamorphization of waters, and long-term accumulation of organic contaminants in low-temperature, reduction and sedimentation barriers. In this paper, some environmental and geochemical effects of diamond mining in the Arctic area are discussed.  相似文献   

探测冰盖和多年冻土层的融冰探头研发     

Norbert I. K 《冰川冻土》2004,26(Z1):310-318

The exploration of ice sheets by melting vertical holes into the ground has some tradition in terrestrial glaciology. Such probes have been used since the 1960's to investigate the vertical structure of the ice in Greenland and Antarctica and in alpine glaciers. In this paper we look into the possibility to develop similar devices for use on extraterrestrial icy bodies, like e.g. the polar areas on Mars or the icy satellites of the outer solar system. We report on some basic experiments performed in the cryo-vacuum laboratory of the Space Research Institute of the Austrian Academy of Sciences, Graz. In these experiments the penetration of a simple melting probe into compact and porous water ice (with a snow-like texture) was monitored, both under vacuum conditions and under air pressure. The observed penetration speeds for a given power supply are compared with a simple mathematical model. We conclude that a miniature melting probe with small overall dimensions and a reasonable power demand could well be part of the payload of a future planetary mission, for example to the poles of Mars. Such missions are currently under discussion in several space agencies. Moreover such probes could also e? ectively be used in terrestrial environments. A possible design is presented at the end of the paper.  相似文献