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详细地介绍了曲墙式、直墙式和圆形断面隧道衬砌在约束条件、隔热保温层及含水状况等因素变化情况下的相似材料冻胀力室内模型试验,通过分析试验得出不同衬砌断面在各种因素影响下衬砌和围岩间冻胀压力的量值和分布特征,以及由冻胀压力引起的结构内力分布特征。研究表明,直墙式断面受冰胀力最大,曲墙式次之,圆形面最小;曲墙式、直墙式断面冻胀力均呈分布荷载形态,前者拱脚及仰拱脚处冻胀力最大,后者边墙、底板处冻胀力最大。 相似文献
3.
区域城镇土地价格体系研究——南京市域城镇案例分析 总被引:6,自引:3,他引:6
建立了区域城镇土地类(型)、等(级)、级(别)和基准地价、宗地地价、商业路线价的城镇土地价格体系,为区域城镇土地管理工作提供了科学依据,并在南京市域城镇土地定级估价工作中得到了较好的实践。 相似文献
4.
CT诊断胸部平片隐匿部位肿瘤的检出价值 总被引:1,自引:0,他引:1
本文对227例胸部肿瘤中的34例X线不易发现的肿瘤进行了X线与CT诊断的对照分析,此组病例共占胸部肿瘤的14.9%,胸部隐匿部位的肿瘤在传统X光正位胸片上受组织重叠的影响是不易看到的,容易漏诊,须通过CT扫描检查方可观察到,CT扫描是诊断胸部隐匿部位肿瘤的最好,最有效的检查方法之一。 相似文献
5.
Discontinuity controlled probabilistic slope failure risk maps of the Altindag (settlement) region in Turkey 总被引:7,自引:0,他引:7
The evaluation of potential rock slope problems using stereographic projection techniques known as kinematic analysis is one of the most important parts of a slope stability investigation to be carried out in jointed rock media. In conventional stereoprojection techniques for the assessment of possible rock slope failures, the peak orientations of joints together with the slope geometry and the friction angle of the weakness planes are used. Other possible joint orientations which may be encountered in the rock media are ignored, although they belong to the group of joint peak orientations. In this study, nearly vertical jointed andesites cropped out at the Altindag settlement region in Ankara were studied in order to evaluate the relevance of this ignored discontinuity orientation data on slope stability. As a result, probabilistic risk maps for planar, toppling and wedge failures were produced using the kinematic rules and digital elevation model of the study area. The comparison of the distribution of the actual failures in the area and the probabilistic risk maps prepared for the study area revealed that all of the identified failures are found to be located in the higher risk zones on the probabilistic risk maps. 相似文献
6.
《The Journal of geography》2012,111(4):143-155
This article examines possibilities associated with the cultivation of balanced regional images via the use of simple methods. Two experiments based on the primacy effect and the painting picture rule, or visual depiction of regions, were conducted. The results show significant differences in the formation of regional images. More specifically, the presentation of positive prior knowledge and the depiction of regional aspects with strong visual cues led to the formation of regional images that were more balanced. In conclusion, these simple teaching methods are effective for cultivating balanced regional images, an important element of geography education. 相似文献
7.
This paper deals with the morphotectonic evaluation of the Delhi region in northern India to understand its impact on land use and urban development. To accommodate heavy urbanization and population rise (being the capital of India), the area has undergone tremendous environmental degradation resulting from a mismatch between adopted land use and morphotectonic considerations. The geomorphic and drainage signatures of the region have evolved out of interaction of varied geological parameters including neotectonic activities. We have evaluated the changes in the drainage pattern of the Yamuna River in the Delhi region to underline its significance in geomorphic evolution and subsequent land use and/or land suitability. The Yamuna River has shown variations both in channel position and geometry over the last two centuries. The observed migration pattern of the river (shifting of confluences, position and disposition of palaeochannels, etc.,) cannot be attributed to normal river phenomenon and appears to have been effected by neotectonic changes. In addition, some case studies are discussed to underline the significance of geomorphic factors in urban development. 相似文献
8.
《Urban geography》2013,34(4):360-382
Many European urban regions have experienced a transformation from a compact monocentric toward a less compact polycentric urban region since the 1960s. The debate on emerging polycentricity in Europe so far tends to be more theoretical than analytical. The trend toward increasingly polycentric urban regions is meanwhile beyond dispute, but the effects of this transformation on urban regions and their components have only been explored to a limited extent. Are the "old" central cities only losing people, functions, and status to the new urban centers, or do these centers complement each other and specialize in terms of economic activities and population composition? This article presents evidence for the Amsterdam urban region regarding population distribution, selective migration, job growth, and economic specializations of the region's subcenters. It will become clear from our data that the Amsterdam urban region has indeed become more polycentric, but also that Amsterdam has managed to remain a vital center. The newer and older urban subcenters have become increasingly important, but rather than competing with Amsterdam, they develop in a complementary way. 相似文献
9.
张明华 《大地构造与成矿学》2007,31(4):418-423
东喜马拉雅南迦巴瓦峰地区地质构造十分复杂,对该区板块缝合带的空间位置问题,长期以来,一直认为沿雅鲁藏布江呈弧形展布。笔者以ETM+为主要信息源,以遥感与GIS为技术支撑,对南峰地区的断裂构造进行了详细的遥感解译分析,从构造统计分析的角度对断裂构造进行定量研究,从分维值及趋势值的空间分布及变化特征分析,认为缝合带的南东段、北段大致沿雅鲁藏布江展布,而北西段位于雅鲁藏布江的北西侧,沿东久-米林(断裂带)展布,这也与近几年来开展了1∶25万区域地质调查获得的新认识相一致。 相似文献
10.
本文通过对豫东、豫北等河南农业主产区80年代以来工业化进程的调研分析,在总结经验教训的基础上,针对这些地区工业发展的特殊条件,提出了平原农区工业化的基本思路和途径,主导产业的选择和注意处理的几个问题。 相似文献