Treatment of Loose to Medium Dense Sands by Granular Piles: Improved SPT ‘N<Subscript>1</Subscript>’ Values     

A. Murali Krishna  M. R. Madhav 《Geotechnical and Geological Engineering》2009,27(3):455-459

The effect of granular pile installation on the modifications induced in loose to medium dense granular deposits is studied. SPT is the most often used to evaluate the in situ soil properties. Expressions for modified SPT N₁ values for different soils, i.e., for different initial SPT N₁ values, were determined as functions of replacement ratio from the available field data. Improvements in the ground are presented in the form of modified or improved SPT N₁ values versus replacement ratio charts, which can then be used to design the required degree of treatment for the expected improvement or to estimate the improved values of treated ground for different initial states of sands.  相似文献   

北京地区河流沉积物的金属元素背景值研究   总被引：1，自引：0，他引：1  

杨惟理 《地理研究》1987,6(2):70-79

本文检验,表征了北京地区河流沉积物的金属元素背景值。并应用多元分析法探讨了金属元素背景值的地球化学活动性、相关组合、区域差异等地球化学特征以以环境要素对形成背景值的影响。  相似文献   

运用数学形态学方法探讨我国干旱-半干旱区降水的可能分布          下载免费PDF全文

秦小光  王润生 《第四纪研究》1997,17(2):28-35

我国北方干旱－半干旱区长期受水资源缺乏的影响，国民经济建设受到很大的制约。因此，研究干旱－半干旱区的水资源成为人们关注的重点。本文借助数学形态学方法，探讨了我国干旱－半干旱区降水在几种气候变化条件下的可能分布，揭示出了西北地区环境最脆弱的地区是塔里木盆地南缘及其东侧的罗布泊、哈密、敦煌地区，同时也探讨了这些地区在降水增加或减少情况下的可能环境分布。  相似文献   

Study on tidal gravity observations obtained at stations Zhongshan and Changcheng, Antarctic   总被引：1，自引：0，他引：1  

Lü Chun-cao 《地震学报(英文版)》2001,14(3):325-332

IntroductionThe purpose of the studies on the tidal gravity observations on the Earth(s surface is to investigate the properties of the deformation and the tidal gravity variations of the Earth under the action of the luni-solar tidal force. These variations relate to the internal structure, shape and the medium(s rheology properties of the Earth (Wahr, 1981; Dehant, 1987). The theoretical studies and observations indicated that the amplitudes and the tidal parameters, including the amplitud…  相似文献   

彩色CRT显示器描述颜色特性的数学模型     

王永宁  刘明亮  朱海红 《武汉大学学报(信息科学版)》1996,(1)

以ＣＲＴ显示器的特征函数与特征矩阵来描述ＣＲＴ显示器的输入／输出色度特性；建立了ＣＲＴ显示器数字驱动输入值与其显示颜色三刺激值之间关系的数学模型。  相似文献   

阿拉斯加北坡巴罗地区(BARROW)水体的pH值和电导率分析     

侯书贵  秦大河  张青松 《地理科学》1997,(1)

根据１９９４年８～９月份在阿拉斯加北坡巴罗地区采集的５类水样（大气降水、河水、湖水、海水和地下水）的实测资料，初步探讨了本区水体的ｐＨ值和电导率的分布特征及环境意义。  相似文献   

南海海水中溶解态铜、铅、锌、镉环境背景值的初步研究   总被引：8，自引：0，他引：8  

于涛 《台湾海峡》2003,22(3):329-333

本文通过对南海海域自然环境中表层海水溶解态Cu、Pb、Zn、Cd的分析，讨论了南海表层海水中重金属含量的分布。根据地理环境特征及表层环流结构将南海表层水域分成北部和南部两个重金属背景值海区，并采用统计学方法对海水中重金属的分布类型进行了态性检验，按分布类型分别确定了Cu、Pb、Zn、Cd的环境背景值。  相似文献   

具有两个公共值和一个公共值对的整函数的唯一性定理     

李效敏  徐会彩 《中国海洋大学学报(自然科学版)》2007,37(6):1045-1050

利用加权分担的思想，证明具有2个公共值和1个公共值对的整函数的一个唯一性定理，改进了Brosch G，Alza-hary TC和Yi H X等人的有关结果。  相似文献   

乔治王岛菲尔德斯半岛地区环境背景值初探   总被引：4，自引：3，他引：1       下载免费PDF全文

赵俊琳  蒙宇  赵承义  周善元  朱光华  于润湖  刘培桐  李果 《极地研究》1989,1(4):44-51

本文探讨了南极乔治王岛菲尔德斯半岛地区岩石、原始土壤(风化壳)、沉积物、地表水、大气降水、气溶胶、生物等环境要素的基本化学组成和物理化学分析方法。本研究可为评价区域环境质量、制定环境标准、确定环境中的元素迁移、转化规律以及为南极资源的合理开发利用提供科学依据。  相似文献   

Estimates of loss in ecosystem service values of Songnen plain from 1980 to 2000     

WANG Zongming  ZHANG Bai  ZHANG Shuqing  SONG Kaishan  DUAN Hongtao 《地理学报》2005,15(1):80-86

Ecosystem services are premises for human beings to exist and develop in the world, and it is of importance to study effects of land use change on ecosystem functions. Songnen plain, located in Northeast China, is one of the national key bases for agricultural production. Because there were remarkable variations in land use in recent years, it can supply specific foundation for protection and restoration of regional eco-environment to explore changes in its values of ecosystem services. This study aims to qualify long-term changes in land use of Songnen plain from 1980 to 2000, and to explore the impact of land use change on ecosystem services. With 2-period land use data using RS and GIS, this paper analyzed changes in land use and in ecosystem service values using the ecosystem service value coefficients (VC) put forward by Costanza et al. Results showed that from 1980 to 2000, area of rangeland, water area and wetlands and area of cropland decreased, but urban area and unused land increased. Due to cropland's comparatively low VC and comparatively high VC of wetlands and water area, increment in cultivated land could not offset the total decrement in regional ecosystem service values because of the decrease in area of wetlands and water area. Meanwhile, city sprawl has also led to loss of ecological values. Total ecosystem service values of the study area reduced dramatically, from 34,926.10×106$ to 31,744.54×106$ in the period 1980-2000. This represents a 9.11% net decline in annual value of ecosystem services in the study area.  相似文献