Reliability based risk index for the design of reinforced earth structures   总被引：1，自引：0，他引：1  

Adnan A. Basma  Samer A. Barakat  Maher T. Omar 《Geotechnical and Geological Engineering》2003,21(3):225-242

The design methods currently used for earth reinforcement are mostly based on deterministic properties of both the soil and the construction materials used. Nowadays, however, the general trend is designing at a specific degree of reliability. This is even more true where the raw data such as soil properties exhibit significant variation. Deterministic solutions, in this case, may not suffice. Therefore, this paper will attempt to use probabilistic formulations thereby modifying the existing design procedure of reinforced earth retaining walls to account for uncertainties and variabilities. Through a first order Taylor's series expansion about the mean, the mean and variance of the strip reinforcing components, namely width and length, are derived in terms of the variations in the soil properties. Design charts that enable estimation of both mean and variance are developed to avoid extensive partial differentiation involved in the computations. Using appropriate probability distributions along with the mean and variance, the final design outputs are determined for a selected failure probability by introducing what is refered to as 'risk index'. The results indicate that the risk index increases with an increase in the coefficient of variations and a decrease in failure probability. Furthermore, it is shown that in some cases, depending on the variabilities of the soil properties, the classical design technique produced a relatively high failure probability. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

鄂豫皖交界地区地震地质背景与中强地震复发特征的研究   总被引：1，自引：2，他引：1  

张杰  王行舟  沈小七  张毅 《地震地磁观测与研究》2003,24(6):18-25

鄂豫皖交界地区位于东大别山西部，历史中强地震(M≥43/4)主要发生在土地岭-落儿岭及商城-麻城断裂带上，且“互动”和“连动”的特征较为显著。根据这一特征，在研究东大别山区域地质、地壳结构、断裂活动及地震构造应力场特征的基础上，可将鄂豫皖交界地区的中强地震作为秦岭-大别山活动地块中的次级地块的整体活动来看待。该区历史地震活动整体表现为丛集特征，而主要发震断层(土地岭-落儿岭断裂)的历史地震活动则具有相对较好的准周期性。地震复发周期研究提示，该地块近期发生M≥5．0左右地震的危险性较大，而霍山-六安地区为未来发生中强地震的主要危险区。  相似文献   

Analysis and study of the large earthquake risk in Yanqing-Huailai basin     

刘昌铨  嘉世旭  刘明军  李长发 《地震学报(英文版)》1997,10(5):639-647

ＡｎａｌｙｓｉｓａｎｄｓｔｕｄｙｏｆｔｈｅｌａｒｇｅｅａｒｔｈｑｕａｋｅｒｉｓｋｉｎＹａｎｑｉｎｇＨｕａｉｌａｉｂａｓｉｎＣＨＡＮＧＱＵＡＮＬＩＵ（刘昌铨）ＳＨＩＸＵＪＩＡ（嘉世旭）ＭＩＮＧＪＵＮＬＩＵ（刘明军）ＣＨＡＮＧＦＡＬＩ（李长发...  相似文献   

青海省湟水盆地历史地震调查及研究     

涂德龙  王赞军  夏玉胜  常振广 《高原地震》1997,(3)

通过对青海省湟水盆地影响较大的5次破坏性历史地震的重新考证，确定了每次地震的宏观震中、震级大小、发震断层以及地震等震线，从而得出盆地东部一平安至民和块体及其周边地区，基底介质强度较弱，为中强地震活动水平较高的危险地区。  相似文献   

1—3年强震危险区预测的指标体系     

戈澍漠  郑福婉 《内陆地震》1997,11(3):193-201

强震危险区预测是当前地震预报中的重要课题之一。笔者以预警活断层、预警活断层分段研究解决断层活动的时间和空间尺度为主线，配合地震活动动态分析、地震波介质特征早期信息、近场趋势性前兆异常和危险性概率预测，确定了判别几年尺度强震危险区的指标。在“八五”地震科技课题研究过程中，圈这了范围不超过１００００ｋｍ＾２的５个强震危险区，已成功地对１９９３年１０月２日若羌６．６级地震、１９９５年５月２日乌苏５．８级  相似文献   

Trends In U.S. Hazardous Materials Transportation Spills     

Susan L. Cutter  Minhe Ji 《The Professional geographer》1997,49(3):318-331

This paper examines historical and spatial trends in hazardous materials transportation spills from 1971 to 1991. While the number of spills Inc.reased steadily during the 1970s, peaking in 1978–1979, there has been a decline in frequency sInc.e then largely due to modifications in reporting. Monetary damages have the opposite temporal pattern, with major Inc.reases recorded from 1982 onward. Death and injury statistics are more variable. Spatially, accidents are more prevalent in the Rust Belt extending from the Northeast corridor westward to the Great Lakes states, as well as in the Southeast. The greatest potential risk to the public is found in smaller, more densely populated industrial states such as New Jersey, Delaware, and Maryland. The spatial distribution, however, has not changed. Potential risk sources (e.g., chemical industry, number of hazardous waste facilities, number of railroad miles) are the best predictors of hazmat Inc.ident frequency. Mitigation efforts (statewide regulatory and/or management policies) also help explain the variability in hazmat Inc.idents.  相似文献   

FARMING THE FOREST EDGE: VULNERABLE PLACES AND PEOPLE AROUND KIBALE NATIONAL PARK,UGANDA     

LISA NAUGHTON-TREVES 《Geographical review》1997,87(1):27-46

ABSTRACT. Subsistence farmers near Kibale National Park, Uganda, fear and resent many wildlife species. In this article I compare records of crop damage by wildlife and livestock with local complaints about the worst animals and the most vulnerable crops. I discuss the concordance and discrepancies in complaints versus actual damage in light of physical parameters of risk and of social factors that shape perceptions and vulnerabilities. Crop losses were greatest at the edge of the forest, where immigrants are disproportionately represented. State proprietorship of wildlife amplifies local vulnerability and constrains traditional coping strategies, such as hunting.  相似文献   

Unsiting Nuclear Power Plants: Decommissioning Risks and Their Land Use Context*     

Martin J. Pasqualetti  K. David Pijawka 《The Professional geographer》1996,48(1):57-69

Nuclear power plant siting provided the first significant public opportunity to examine nuclear safety and to affect nuclear policy. These discussions were prompted and fueled by perceptions of nuclear risk. Now, as we begin the process of nuclear decommissioning, we are finding that power plant removal—unsiting–is also likely to attract public interest. This paper presents a preliminary survey of how we are likely to react to this emerging theme, applying these findings within a land use context to see if it is likely to produce issues salient to the public. In so doing it also examines how these issues could affect decommissioning timing and type. It suggests that the most likely prospect is that power plants will remain on the landscape long after they are closed.  相似文献   

全国地质灾害趋势预测及预测图编制   总被引：13，自引：0，他引：13  

殷跃平  张颖  康宏达  费宇明 《第四纪研究》1996,16(2):123-130

区域地质灾害预测是地质灾害研究的难题。本文运用基于地理信息系统的风险评价方法对这一问题进行了探讨。将全国剖分为２７００个单元，对地质灾害进行现状评价，并与已数字化的地质灾害图件进行单要素叠加，编制了全国地质现状等值线图，在现状评价基础上，对地质灾害进行趋势预测，将降雨条件、区域地震活动、区域地壳稳定程度、区域岩组条件和人类工程活动等作为区域地质灾害演变的因素，运用模糊综合评判模型进行综合评判，编制了１：６００万中国地质灾害趋势预测图。  相似文献   

Prediction of volumes and risk in hydrocarbon exploration: a quantification of geology     

H. J. Nijhuis 《International Journal of Earth Sciences》1997,86(2):322-331

 The prediction of the hydrocarbon potential of a specific trap or of a number of specific traps (venture), referred to herein as prospect appraisal, concerns a probabilistic exercise based on the quantification of geology in terms of structural closure, reservoir quality, hydrocarbon charge, and the retention potential of the seal. Its objectives include: (a) prediction of the hydrocarbon volumes that could be present in the trap from an analysis of its geologic attributes; (b) the amount of uncertainty introduced in the volumetric prediction by the uncertainties in the subsurface geology; (c) the risk that one or more of the essential attributes of the prospect are underdeveloped and recoverable reserves are absent. The uncertainty of the geologic input requires a probabilistic approach, for which the Monte Carlo procedure is well suited. Prospect appraisal forms the basis for decision-making in oil exploration and development and, therefore, should be reliable, consistent, and auditable. This requires the use of a consistent methodology, the development of reliable models to quantify the geologic processes involved, and the collection of comprehensive and relational databases for the many geologic variables. As a result of data availability, uncertainty and risk tend to increase strongly from mature, producing basins to areas of frontier exploration. This may complicate management of exploration portfolios. Received: 1 July 1996/Accepted: 25 November 1996  相似文献