Back-analysis of a seismically induced highway embankment failure during the 1999 Düzce earthquake     

Ömer Aydan  Reşat Ulusay 《Environmental Geology》2002,42(6):621-631

An earthquake of magnitude 7.2 on the Richter scale occurred on 12 November 1999 in the Düzce-Bolu region of Turkey. The region was also hit approximately 3 months before during the devastating Kocaeli earthquake of 17 August 1999. Besides high casualties and damage to various engineering structures and buildings, slope and embankment failures on the highway and the country roads occurred. In this study, the authors are concerned with the back-analysis of an embankment failure that occurred on the four lanes E-5 highway connecting Ankara to Gstanbul at Bakacak in the Bolu Province during the 1999 Düzce earthquake. Both pseudo-dynamic and dynamic limiting equilibrium methods are used to back analyse the conditions for the initiation of failure and also displacement responses of the embankment during the earthquake shaking. After having given a brief summary of the investigations on the post-failure state, the geology and geotechnical characteristics of the site, and the dynamic limiting equilibrium method developed and used for analyses are described. The results of the back-analysis based on a pseudo-dynamic approach, revealed that the maximum ground acceleration to initiate the failure of the embankment was probably about 0.125 g. On the other hand, the application of a method for computing the displacement and velocity responses of the failed embankment showed that the failure was possible when the embankment was subjected to ground accelerations similar to that recorded at the Düzce station. In addition, the computations also revealed that the time history of accelerations could be very important for the failure of slopes and embankments.  相似文献   

Exploration and Study on Deep Crust Structural Characteristics in the Jiashi-Artux Seismic Region     

Zhao Jinren  Zhang Xiankang  Zhang Chengke  Ren Qingfang  Cheng Shuangxi  Zhang Jianshi  Nie Wenying  PAN Shuzhen 《中国地震研究》2003,17(2):103-112

The data from two deep seismic sounding profiles was processed and studied comprehensively. The results show that crnst-mantle structures in the investigated region obviously display layered characteristics and velocity structures and tectonic features have larger distinction in different geological structure blocks. The boundary interface C between the upper and lower crust and Moho fluctuate greatly. The shallowest depths of C (30.0km) and Moho (45.5km) under Jiashi deepen sharply from Jiashi to the western Kunlun mountain areas, where the depths of C and Moho are 44.0km and 70.0km, respectively. The higher velocity structures in the Tarim massif determine its relatively “stable“ characteristics in crust tectonics. The phenomenon in the Jiashi region, where the distribution of earthquake foci mostly range from 20kin to 40kin in depth, may infer that the local uplift of C and Moho interface, anomalonsly lower velocity bodies and deep large faults control earthquake occurrence and seismogenic processes in the Jiashi strong earthquake swarm.  相似文献   

Geotechnical and geoenvironmental characteristics of man-made underground structures in Cappadocia, Turkey     

mer Aydan  Re at Ulusay 《Engineering Geology》2003,69(3-4):245-272

Underground cities and semi-underground settlements, most of which are 1500 years at least, exist in the Cappadocia Region of Turkey. These man-made rock structures are carved in soft tuffs and the best examples of long-term performance of man-made structures in the field of rock engineering. The tuffs also have good thermal isolation properties to be used as housing and storage of foods. In this article, the authors are only concerned with physical and short-term mechanical characteristics due to the wide-spectrum of the theme and the in situ characterization of the Cappadocia tuffs, and the results of investigations are presented. In addition, a critical overview on possible engineering geological problems at Cappadocia with mechanical aspects of historical and modern rock structures and their implications in rock engineering is made. From the experimental results in the field, it is evident that the engineering characteristics of these rocks do not show significant changes in vertical and horizontal directions. However, they are prone to atmospheric conditions. In addition, temperature and humidity measurements at different floors of the underground cities and various parts of semi-underground settlements indicated that variations in climatic conditions of the openings are very small when compared to those outside the ground surface.  相似文献   

长白山天池火山区长白-敦化剖面结晶基底的探测和研究     

潘素珍  张先康  杨卓欣  张成科  赵金仁  潘纪顺  任青芳  张建狮 《地震研究》2003,26(3):271-274

时间项分析法中，应用广义最小二乘法进行反演，对长白山天池火山区岩浆系统的长白—敦化(L1)剖面的Pg波到时进行了计算处理，得到了Pg波时间项及基底速度值；取上部地壳的介质平均速度为4．5km/s，经反演求得了各点的深度值，给出了长白山天池火山区结晶基底的厚度分布。结晶基底厚度一般在2．0km左右，而在长白山天池下方结晶基底最厚处接近4．0km；在万宝和敦化附近各有一不太明显的凹陷，其原因可能与在这两个位置处有几条断裂穿过有关。  相似文献   

An Integrated Geomechanical Investigation,Multi-Parameter Monitoring and Analyses of Babadağ-Gündoğdu Creep-like Landslide     

Halil Kumsar  Ömer Aydan  Hisataka Tano  Sefer Beran Çelik  Reşat Ulusay 《Rock Mechanics and Rock Engineering》2016,49(6):2277-2299

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变化环境下石羊河流域年径流频率计算          下载免费PDF全文

李伶杰  宋松柏  王银堂  胡庆芳  王磊之 《水文》2016,36(4):19-25

受气候变化与人类活动的影响,水文序列一致性遭到破坏,传统的频率计算方法受到挑战。针对石羊河流域8条河流年径流量序列,在基于水文变异诊断系统进行变异分析的基础上,采用条件概率分布法和混合分布法进行了变化环境下的年径流频率计算。结果表明,石羊河流域年径流量序列以向下跳跃变异为主,变异年份多集中在1960年附近;变异序列的两种分布均通过K-S检验,最优分布的拟合效率系数均大于0.97;对比由考虑变异的理论分布与不考虑变异的一致性P-III型分布确定的设计年径流量,当设计频率高于90%时,大靖河与西营河的设计年径流量值相差较大。因此,石羊河流域新建水利工程的规划设计,应适当考虑水文资料的变异特性,选择合理的频率分析方法确定设计年径流量。  相似文献   

Carcinogenic risk evaluation for human health risk assessment from soils contaminated with heavy metals     

D. M. Cocârţă  S. Neamţu  A. M. Reşetar Deac 《International Journal of Environmental Science and Technology》2016,13(8):2025-2036

Human activities have progressively increased in recent years. Consequently, significant environment deterioration resulted. Soils have a particularly varied vulnerability to heavy metal pollution, especially in the vicinity of industrial areas. Heavy metal contamination of soil may induce risks and hazards to humans and the ecosystem, while toxic metals in soil can severely inhibit the biodegradation of organic contaminants. This paper is focused on human health risk assessment from extremely contaminated soil with heavy metals, mainly with carcinogenic elements. The study refers to an agricultural area in the vicinity of an old metallurgical processing industrial facility. The contaminants evaluated in the present paper are beryllium (Be), cadmium (Cd), chromium (Cr), nickel (Ni) and lead (Pb). Contamination level is pointed out through laboratory analysis results of soil samples taken from 0–0.2 m, 0.2–0.4 m soil layers and up to 2.1 m soil depth. Some heavy metal concentrations (Cd, Cr and Pb) exceed the intervention thresholds for sensitive areas, as they are stipulated in the national regulation in Romania. The identified average concentration levels of Cd, Cr^VI and Pb in the first layer of the investigated land are 23.83, 7.71 and 704.22 mg/kg_d.w, respectively. The results show that the potential risk of human health is relevant (higher than the acceptable one after World Health Organization) and a possible solution for the remediation should become a major concern for the investigated area.  相似文献   

油田井间CT技术应用试验     

刘庆芳  闫锐 《CT理论与应用研究》1994,3(4):28-33

本文记述了在扶余油田采用井间电磁波和声波ＣＴ方法进行的试验。阐述了试验的意义、理论基础、计算方法、实施方案及成果几方面。试验结果表明电磁波的工作频率应降低到至少几百ＫＨｚ以下才能适于油田应用。１００ｍ井间距的声波成像获得了成功，两个油层均有清晰显示。最后，对技术的发展提出了建议。  相似文献   

Entrepreneurship, ethnicity and local contexts: Hispanic entrepreneurs in three U.S. southern metropolitan areas   总被引：1，自引：0，他引：1  

Qingfang Wang  Wei Li 《GeoJournal》2007,68(2-3):167-182

Previous research suggests that entrepreneurship can provide ethnic minorities a springboard for economic advancement and social integration. However, self-employment rates vary significantly among ethnic groups, between men and women, and in different places. The prevailing literature suggests that personal characteristics, including human capital attributes, ethnic networking, institutional regulations, societal structures and discrimination, all contribute to the differential ethnic entrepreneurship rates. However, very few recent studies have analyzed how different urban socio-economic contexts influence this process. Using the 2000 Public Usable Microdata Samples (PUMS), this study examines how Hispanic entrepreneurs perform in three different metropolitan areas in the US South. The results show that the ethnic diversity, history of immigration, and the economic structure in each local area have provided different opportunities and challenges for Hispanics to start up and maintain their own businesses. This study suggests that the process of economic incorporation of ethnic minorities and immigrants depends significantly on the institutional capacity and social, cultural and political resources of local communities.  相似文献   

大同阳高震区及其邻区壳幔速度结构与深部构造   总被引：2，自引：1，他引：1       下载免费PDF全文

张成科  张先康  盖玉杰  赵金仁  聂文英  任青芳 《地震地质》1998,20(4):104

利用通过本区６条宽角反射／折射剖面资料对大同阳高震区及邻区地壳上地幔速度结构与构造进行了详细的研究。结果表明,地壳上地幔速度结构与构造在纵向和横向上具有明显的不均一性。浅部基底断裂发育,而在其深部,根据波组特征、壳内界面及速度等值线起伏变化和低速异常体的边界等推测有３处地壳深断裂带。本区最明显的上地壳低速体位于大同—阳原附近,其南界存在地壳深断裂,大同阳高地震群与该低速异常体和深断裂有关。  相似文献