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31.
John R. Greenwood Joanne E. Norris Jo Wint 《Geotechnical and Geological Engineering》2006,24(3):467-481
The procedure for geotechnical site investigation is well established but little attention is currently given to investigating
the potential of vegetation to assist with ground stability. This paper describes how routine investigation procedures may
be adapted to consider the effects of the vegetation. It is recommended that the major part of the vegetation investigation
is carried out, at relatively low cost, during the preliminary (desk) study phase of the investigation when there is maximum
flexibility to take account of findings in the proposed design and construction. The techniques available for investigation
of the effects of vegetation are reviewed and references provided for further consideration. As for general geotechnical investigation
work, it is important that a balance of effort is maintained in the vegetation investigation between (a) site characterisation
(defining and identifying the existing and proposed vegetation to suit the site and ground conditions), (b) testing (in-situ and laboratory testing of the vegetation and root systems to provide design parameters) and (c) modelling (to analyse the
vegetation effects). 相似文献
32.
论述了宁夏回族自治区土壤元素含量和农作物优质高产与土壤环境中化学元素N、P、K、S、Fe、Mn、Cu、Zn、B、Mo、V、Sr、Ti、Mg、La、Ce、Pr、Nd、Sm、Eu、Y、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Ca、Co、Ni、F、Tl、Si、Na、Cr、Pb、Cd、Hg、Se、Ba、Te、Ta有密切的关系.提出了生态农业地质研究的目的、内容、方法、管理及其前景。 相似文献
33.
黔东南地区短期气候预测方法研究 总被引:2,自引:0,他引:2
根据大气环流特征和小气候相关关系,找出预测黔东南地区春季倒春寒、3~6月降水量趋势、夏季及6~8月气温变化趋势和夏季旱涝趋势指标,用以制作黔东南地区长期天气趋势预测。 相似文献
34.
35.
A. Ankilov A. Baklanov M. Colhoun K. -H. Enderle J. Gras Yu. Julanov D. Kaller A. Lindner A. A. Lushnikov R. Mavliev F. McGovern T. C. O'Connor J. Podzimek O. Preining G. P. Reischl R. Rudolf G. J. Sem W. W. Szymanski A. E. Vrtala P. E. Wagner W. Winklmayr V. Zagaynov 《Atmospheric Research》2002,62(3-4)
During an international workshop at the Institute for Experimental Physics of the University of Vienna, Austria, which was coordinated within the Committee on Nucleation and Atmospheric Aerosols (IAMAS-IUGG), 10 instruments for aerosol number concentration measurement were studied, covering a wide range of methods based on various different measuring principles. In order to investigate the detection limits of the instruments considered with respect to particle size, simultaneous number concentration measurements were performed for monodispersed aerosols with particle sizes ranging from 1.5 to 50 nm diameter and various compositions.The instruments considered show quite different response characteristics, apparently related to the different vapors used in the various counters to enlarge the particles to an optically detectable size. A strong dependence of the 50% cutoff diameter on the particle composition in correlation with the type of vapor used in the specific instrument was found. An enhanced detection efficiency for ultrafine hygroscopic sodium chloride aerosols was observed with water operated systems, an analogous trend was found for n-butanol operated systems with nonhygroscopic silver and tungsten oxide particles. 相似文献
36.
随着油田开发难度的加大,开发中仅仅把储集砂体的沉积相类型确定下来是远远不够的,还要求准确地预测砂体的宽度、长度等定量参数,这就是本文所指的沉积相定量研究。本文根据大量钻井资料,在地层精细划分对比的基础上,对青海砂西油田E31辫状河三角洲平原和曲流河三角洲平原进行了定量研究,确定了分流河道砂体的宽度、宽/厚比等参数。研究表明,本区辫状河三角洲平原的分流河道砂体宽多为 1200-3000m,厚多为5-10m,宽/厚比200-280。曲流河三角洲平原的分流河道砂体宽多为 400-700m,厚多为3-6m,宽/厚比80-110。辫状分流河道砂体比曲流分流河道砂体普遍宽、厚是由于辫状分流河道频繁摆动改道引起砂体的横向拼合和垂向叠置所致。这种河道可称复合河道。利用“厚度中心法”可区分复合河道与单河道。由于不同沉积相的砂体宽度不同,在油田开发中井网部署方案应该不同。 相似文献
37.
通过一项工程和不同参考椭球转换软件的实现过程,探讨了不同参考椭球GIS数据的转换问题.首先介绍了转换的数学模型和软件的实现过程.其次介绍了几种转换方法,并通过一个工程实例介绍了具体的操作步骤.最后对这个工程实例进行了可行性分析. 相似文献
38.
39.
A multi-scale study on land use and land cover quality change: The case of the Yellow River Delta in China 总被引:5,自引:0,他引:5
This paper presents a case study of the Yellow River Delta in China, to trace land use and land cover changes during the past
20 years, with an emphasis on land quality changes. Three sets of data are used in this case study: remote sensing data derived
from satellite images; crop yield data from statistics; and soil data collected by the researchers in the field. Our study
reveals that at the regional scale, LUCC has taken place in a positive direction: vegetation cover has been expanding and
crop yields per hectare have been on rise. However, while the overall eco-environment has improved, the improvement is uneven
across the Delta region. At local levels, some areas show signs of increased salinization and declining organic content. Both
natural forces and human activities are responsible for the LUCC, but human activities play a more important role. While some
impacts of human activities are positive, the damages are often long-lasting and irreversible. We also conclude that it is
necessary to use both macro data (such as remote sensing data) and micro data (data collected in the field) to study land
quality change. The former are efficient in examining land quality changes at the regional scale, the latter can serve to
verify ground patterns revealed from macro data and help to identify local variations, so as to get a comprehensive understanding
of LUCC and promote sustainable land use and land management.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
40.