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1.
均质土坡圆弧滑动分析通常需要对圆心坐标和半径的3个参数进行搜索。通过分析圆心水平坐标即圆弧平移对失稳指数的影响,确认危险圆弧或通过坡脚,或圆心水平坐标由半径确定。利用不等式证明垂直边坡的临界滑面通过坡脚,且滑出角度大于内摩擦角。纯黏性边坡倾角大于 后圆弧滑面通过坡脚;而小于该角度圆心在坡面中垂线上,滑出角度?66.78?的圆弧在半径趋于无限时成为最危险滑面,相应的边坡临界高度为 ,保持恒定。具体计算表明,内摩擦系数为0.05,0.1和0.2时,边坡倾角小于40?,34?和22?时最危险滑面不过坡脚,但相应的失稳指数与过坡脚滑面的数值相差不到2 %;内摩擦系数大于0.3后最危险滑动圆弧都通过坡脚。就此而言,在评价均质边坡临界高度时直接对过坡脚的圆弧进行搜索即可。本文结果是基于数学分析得到的,可以作为边坡数值计算程序的参考。 相似文献
2.
Martin Oteng-Ababio 《GeoJournal》2011,76(5):551-560
In recent years, solid waste management (SWM) policies and programmes have received lots of attention in the menu of most
political leaders in developing countries. However, these concerns often focus on the efficiency criterion. Even that, efficiency
is only narrowed down to the removal of waste from residential areas without much concern for either its safe disposal or
its impact on the environment in case of improper waste disposal. There is little attention on reducing waste flows (through
reuse, recycling and composting), or exploiting its economic value. The results of such blatant omission include threats to
public health, environmental deterioration and lack of attention to waste as a resource. This study examines the key barriers
to effective SWM practices in the Greater Accra Metropolitan Area and attests to the marginalization of waste treatment and
disposal practices. It recommends that these missing links must be addressed through network service arrangements to ensure
sustainable urban environment management. 相似文献
3.
在非开挖钻进工程中,穿越曲线的设计是第一个关键的工作,而只有根据现场条件设计计算出合适的穿越曲线,才能保证整个钻进穿越工程的顺利进行和完成。本文在满足相关规范要求的基础上,建立了穿越曲线的计算模型,并利用MATLAB计算程序对其进行优化计算,确定最短穿越距离,使得穿越工程费用最经济。通过现场工程的验证,该计算模型对现场施工有一定的指导意义。 相似文献
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TM图像在成都市演变研究中的应用 总被引:3,自引:0,他引:3
通过TM图像研究城市空间形态,获知城市演变规律,服务于城市规划、建设和管理,已成为城市遥感应用的一个新领域。成都是中国西部的城市明星,其发展过程凝聚了物质和精神财富的精华,通过TM图像研究其演变,对建设和谐的成都具有重要的指导意义。利用成都市1988年和2003年的陆地卫星遥感TM图像,采用目视解译方法,结合同一时期成都市相关文字图表资料,从小比例尺图像上获取城市演变的宏观信息,从大比例尺图像上获取城市演变微观信息。研究表明,成都市从1988年到2003年具有空间结构形态演变与城市非物质演变的辨证统一和城市发展以人为本演变规律。 相似文献
6.
宁蒗盆地地处扬子古陆块的活动边缘,在构造上亦属吸纳和调节印度-欧亚大陆碰撞应力应变的构造转化带。为了研究云南宁蒗地区新生代盆地形成、演化与区域构造的关系及盆地类型,通过对宁蒗地区开展的数幅1∶5万区域地质调查,分析了宁蒗盆地内部及相邻地区的构造格架特征,认为盆地的形成及演化均受控于断裂;通过对宁蒗新生代盆地的沉积建造、控盆构造的时空演化及区域地质背景的研究,认为宁蒗盆地是比较典型的走滑拉分盆地,其演化经历了3个阶段古新世末至始新世初盆地拉分打开阶段、始新世初至始新世末拉分盆地沉积阶段、始新世末至中新世盆地改造阶段。 相似文献
7.
岩爆是地下工程掘进过程中所遇到的一种动力地质灾害,极大地威胁着施工人员和设备的安全。论述了岩爆的定义、特征及作用机理。结合国内外相关岩爆判据判定和理论分析,通过有限元数值模拟,对西华岭隧道开挖中是否会产生岩爆等施工地质灾害做出了最终的判定。 相似文献
8.
Rana P. B. Singh Prof. Dr. 《GeoJournal》1992,26(2):139-147
The roots of Hindu geographic thought can be traced to the remote past, going back at least to c. 3500 BC. Formerly the unity of Nature and Man was expressed in the context of religious activities. The idea of nature and human integrity in Hindu thought depends upon ways in which people see and experience themselves, their sense of attachment to nature, and their ways of maintaining this. It is through symbolism, the main expression of mythological understanding, that one can gain insight into the relationships of humanity to Nature. Creation and incarnation myths describe the origin of organic life and of its five basic elements. The integrity of dwelling in space is expressed through the notion of home. Religion plays a vital role in the Hindu quest for harmony between nature and humanity.Mystics understand the roots of the Tao but not its branches; scientists understand its branches but not its roots. Science does not need mysticism and mysticism does not need science; but man needs both (Capra 1976, p. 297). 相似文献
9.
An investigation into strength and porous properties of metamorphic rocks in the Himalayas: A case study 总被引:1,自引:0,他引:1
M. N. Bagde 《Geotechnical and Geological Engineering》2000,18(3):209-219
If a rock is porous in nature, the genetic complexity associated with its petrofabric makes it difficult to predict its behavior. Here, a comprehensive study of the porous nature, physical and geotechnical responses of three varieties of schist, i.e. quartz mica schist, quartz mica schist with quartz veins and biotite schist of low grade metamorphism obtained from Nathapa-Jhakri hydroelectric project site in the foot hills of Himalayas, India, has been presented. The porous nature of the schists has been brought out through the Mercury Intrusion Porosimetry (MIP) testing and strength behavior through uniaxial testing. Through an experimental invesigation, the porous nature and pore size distribution parameters from MIP, which are closely related to the strength and performance of metamorphic schistose rocks, have been studied. The significance of the porous nature and its response for consideration in the design is emphasized. 相似文献
10.
C. Scheib J.D. Appleton J.C.H. Miles E. Hodgkinson 《Proceedings of the Geologists' Association. Geologists' Association》2013
Radon exposure is a chronic and serious geohazard but with the correct knowledge of its distribution provided by an accurate radon potential map, this risk to human health can be reduced through well directed radon testing programmes and building control regulations. 相似文献
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J. Muldavin 《Geoforum》1997,28(3-4)
China's contemporary paradox springs from spectacular economic growth built upon a foundation of environmental degradation. Combined with rapid social stratification, serious challenges to the state's legitimacy result at a time when its ability to meet the needs of the broad majority is constrained by both structural and political limitations. These contradictions will become increasingly apparent as more critical assessments are made of the reform era. The agrarian sector, through articulation into new markets, is being transformed through short-term practices that emphasize individual income over long-term sustainable development. Using a multi-level analysis, this paper illustrates these issues through village and household case studies in northeast China, contextualized within a brief overview of the reform era, and China's rapidly changing global position. 相似文献
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The northern pipefish,Syngnathus fuscus, is an abundant component of estuarine faunas along the east coast of the United States, yet little is known of its life history. Northern pipefish were collected from several areas in southern New Jersey, particularly the Great Bay-Little Egg Harbor estuarine system, to determine aspects of its reproduction and to estimate its age and growth. A monthly gonadosomatic index for both males and females indicated a spring through summer spawning period, with a peak in reproductive activity during June. A male brood pouch-somatic index indicated a prolonged male brooding period over spring through summer, with a peak in June. The size of males with broods ranged from 119–222 mm total length (TL), and the number of eggs within a brood varied from 45 to 1380. Individual embryos within a brood were identical in development stage, suggesting each brood resulted from a single mating. Young-of-the-year occurred in samples from May through November, with peak abundance in June. Individuals in this year class were extremely variable in size by the end of the first growing season, varying from 5 mm TL to 200 mm TL in November. At approximately 1 yr of age, individuals were 70–220 mm TL and many were of sufficient size to reproduce, indicating that the events of the first year of life for this species are of central importance to an understanding of its population dynamics. 相似文献
15.
Acta Geotechnica - Helical soil nails are passive elements installed in the soil which attains its bond strength through skin friction and bearing from helices. The present study examines the... 相似文献
16.
通过对渗透前后垃圾填埋场渗滤液进行化学成分的测定和分析,研究了GCL的吸附能力及其变化规律,并采用X射线荧光光谱分析对试验结果进行了验证。研究结果表明在渗透过程中GCL对渗滤液中的有机物和阳离子存在吸附作用,水化液对GCL的吸附能力有一定影响;在渗透开始阶段,GCL对垃圾渗滤液中阳离子和有机物的吸附能力比较强,而后逐渐达到吸附饱和状态而丧失吸附能力,因此用GCL作为防渗屏障,主要是依靠其低渗透特性,而非其对溶液中有机质和有害离子的吸附作用。通过对膨润土进行X射线荧光光谱分析也发现:经过渗透后的膨润土中除常见氧化物外,还有来自渗透液中被吸附的物质,但含量不大。 相似文献
17.
Hydrogen sulfide occurs in high concentration (10–200 mg/l) in different parts of Kuwait City and its suburbs at relatively
shallow depths (15–40 m from the surface). This was revealed by drilling through the aquifer system underlying the city and
sampling and analyzing the ground water at the drilled locations. The near-absence of coliform bacteria in the sulfide-rich
zones, the presence of sulfur-reducing bacteria in the deep (>80 m) Dammam Formation aquifer and a linear positive relation
between the concentration of hydrogen sulfide and the total dissolved solids content suggested non-anthropogenic origin of
the sulfide in the ground water of Kuwait. The upward movement of sulfide-rich water from depth and its differential flushing
by surface recharge through outcrops of the aquifers appear to have given rise to the present distribution of hydrogen sulfide
in the aquifers underlying the Kuwait City. 相似文献
18.
V. B. Lapshin A. V. Patonin A. V. Ponomarev M. G. Potanina V. B. Smirnov S. M. Stroganova 《Doklady Earth Sciences》2016,469(1):705-709
A rock behavior experiment with uniaxial compression revealed the effect of acoustic activity in loaded fluid-saturated Berea sandstone samples in response to an electric current. It is established that it is substantially intensified in periods of the current impact and decreases after its cut-off. The current impact also results in a growth of radial deformation indicating an increase in the sample volume. The effect of acoustic activation increases in response to increased heat emitted by the electric current during its flow through the sample, which allows the discovered effect to be explained by initiation of its destruction due to thermal expansion of the fluid in rock interstices and fissures. 相似文献
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