Field studies on dynamic properties of reinforced earth     

S. Boominathan

K. Senathipathi

V. Jayaprakasam 《Soil Dynamics and Earthquake Engineering》1991,10(8):402-406

The concept of reinforced earth has not become popular in the case of foundations for buildings. Presumably, the practical difficulties in application and the exorbitant cost have outweighed the beneficial aspects of ‘Reinforced Earth’ in such applications. Block foundations which are usually provided for machines to take care of the dynamic loads are small and compact and the improvement of the base with reinforcements should not be a difficult or impractical proposition. In this investigation, the feasibility of improving the dynamic properties of soil b ase by applying high modulus materials, such as steel wires and low modulus materials as geotextiles, and a combination of both have been studied in a standard forced vertical block resonance test. The feasibility and the supremacy of the ‘Reinforced Earth’ with the reinforced bases of (i) mild steel frame stiffened with high tensile wires (ii) sand coated geotextiles with the inclusion of a thin layer of frictional sand and (iii) sand coated geotextiles stiffened with welded mesh, have been brought out.  相似文献   

Quasilongitudinal approximation for whistler-mode waves in the magnetospheric plasma     

S. S. Sazhin

R. B. Horne 《Planetary and Space Science》1990,38(12):1551-1553

The range of applicability of an improved quasilongitudinal approximation for whistler-mode waves in the equatorial magnetosphere (4 L 6.6) is specified based on the direct comparison between numerical solutions of the hot electromagnetic dispersion equation with the corresponding analytical quasilongitudinal solutions. It is pointed out that this approximation can be used at frequencies ω less than but not close to the electron gyrofrequency Ω (ω 0.6 Ω) and wave normal angles θ less than but not close to the resonance cone angle θ_R. At ω = 0.8 Ω the analytical results deviate considerably from numerical ones due to the strong damping of the waves, and so the quasilongitudinal solution becomes no longer valid.  相似文献   

利用局部观测资料对参数进行变分反演的初步研究     

张瑰  李振兴 《海洋预报》2008,25(2):59-63

本文考虑一维抛物型偏微分方程的反问题,在已知某一点的局部观测资料下利用变分方法对方程中的未知参数进行反演.在特定的初始条件下,得到了最优的反演参数,研究了测量误差对于参数的影响,并进一步对所得参数的收敛性和收敛精度进行了分析.  相似文献   

南海及其周缘地区全新世海平面遗迹的构造含义南海及其周缘地区全新世海平面遗迹的构造含义     

孙桂华  邱燕  朱本铎 《海洋学报(英文版)》2009,28(5)

通过对海南岛海岸带野外考察，在文昌市铜鼓岭石头公园观察到高程为30 m的海平面遗迹，在东方市黄流镇观察到高程为25～35 m的海平面遗迹，在三亚市鹿回头观察到高程为25 m的海平面遗迹。综合研究前人在该区关于海平面变化的研究成果，得出如下几点初步认识：（1）南海及其周缘地区中全新世以来海平面呈下降趋势，海平面最高位置出现在7 000 a左右、高于现代海平面3 m左右的位置；（2）南海中全新世以来海平面遗迹所揭示的古海平面高程的差异性是古海平面本身持续下降和该区地壳差异性垂直运动共同作用的结果；（3）南海及其周缘地区中全新世期间中央海盆及其西缘的珠江口、红河、湄公河和昭披耶河4个河流三角洲地区为构造沉降区，而南海周缘的台湾岛、雷州半岛、印支半岛、南马来半岛、爪哇岛和苏拉威西岛6个地区为构造抬升区，抬升幅度最大的地方在台湾岛。  相似文献   

羌塘地体内部双湖—冈玛错—龙木错构造带地质与地球物理特征   总被引：4，自引：2，他引：2       下载免费PDF全文

郑洪伟  贺日政杨 贵 《中国地质》2012,39(5):1229-1235

本文概要总结了羌塘地体内部的双湖—冈玛错—龙木错构造带地质与地球物理特征。从地表出露的蓝闪片岩、混杂堆积和生物古地理特征的差异,以及重力异常带分布、Pn波异常特征及地震层析成像等可以看出,双湖—冈玛错—龙木错构造带很可能是冈瓦那大陆和欧亚大陆之间的缝合带。  相似文献   

铁矿石物相中磁性铁测试方法的改进     

庞艳秋  何贵 《四川地质学报》2009,29(Z1)

在传统的铁矿石物相分析中,磁性铁用盐酸溶解,有的样品溶解不完全,故而造成各单项加和低于全铁分析结果.笔者通过试验,发现用硫磷混酸或残渣碱熔能很好地分解磁性铁,使单项加和与全铁分析结果一致.  相似文献   

喀勒隆多金属矿银矿物特征及利用方向     

何贵  胡夕鹏 《四川地质学报》2009,29(4):409-411,417

四川省甘孜州喀勒隆银铅锌矿床,有工业价值的矿脉多达11条,共伴生元素多。通过电子探针、化学分析、显微镜鉴定及野外观察等方法,对银矿物物理性质、化学成分及银的赋存状态进行了研究。初步查明含银矿物主要有银黝铜矿、锑银矿、深红银矿、辉银锑铅矿。银主要存在于方铅矿、银黝铜矿中。了解其特征,为银矿物的利用提供了指导依据。  相似文献   

Biodegradability of trimethylbenzene isomers under the strictly anaerobic conditions in groundwater contaminated by gasoline     

Yu Dao Chen  Lai Gui  James F. Barker  Yaping Jiang 《Environmental Geology》2009,56(6):1123-1128

Trimethylbenzene (TMB), as a constituent of gasoline, is often expected to be used as a conservative tracer in anaerobic BTEX-contaminated groundwater site to correct for attenuation due to dispersion, dilution and sorption along a flow path. To evaluate the suitability of using TMB as a tracer and to better understand biodegradability of TMB in contaminated groundwater by gasoline under anaerobic conditions, laboratory microcosms were conducted with mixed nitrate/iron/sulfate electron-acceptor amendments, using aquifer materials collected from Canadian Forces Base (CFB), Borden, Ontario, Canada. The results showed that under denitrifying conditions, biodegradation of 1,3,5-TMB, 1,2,4-TMB and 1,2,3-TMB were relatively slow and after 204 days of incubation approximately 27, 24, and 16% of the initial concentrations, respectively, were degraded in the microcosms. Under sulfate-reducing conditions, TMB isomers were recalcitrant. In contrast, significant biodegradation of TMB was observed under iron-reducing conditions. 1,3,5-TMB, 1,2,4-TMB and 1,2,3-TMB were degraded to 44, 47, and 24% of initial concentrations with first-order biodegradation rate constants of 0.003, 0.006 and 0.013 d⁻¹, respectively. This study indicates that TMB biodegradation is insignificant under nitrate and sulfate-reducing conditions but significant under iron-reducing conditions. Therefore, the use of TMB as a tracer for interpreting removal of other biodegradable gasoline constituents such as BTEX requires caution, especially in the presence of iron-reducing conditions.  相似文献   

Cretaceous Oceanic Redbeds: Implications for Paleoclimatologyand Paleoceanography   总被引：4，自引：0，他引：4  

WANG Chengshan  HUANG Yongjian  HU Xiumian  LI Xianghui State Key Laboratory of Oil/Gas Reservoir Geology  Exploration  Chengdu Universityof Technology  Chengdu  Sichuan  College of Earth Science  Chengdu University of Technology  Chengdu  Sichuan Department of Earth Science  Nanjing University  Nanjing  Jiangsu China University of Geosciences  Beijing 《《地质学报》英文版》2004,78(3):873-877

The Cretaceous is among the most unusual eras in the geological past. Geoscience communities have been having great concerns with geological phenomena within this period, for example carbonate platforms and black shales in the Early and Middle Cretaceous respectively, during the last decades. But few people have paid any attention to the set of pelagic redbeds lying on the black shales, not to mention the applications to paleoclimatology and paleoceanography. It is shown by the sedimentary records of redbeds, that they were deposited around the CCD, with both a higher content of iron and much lower concentrations of organic carbon, which implies conditions with a  相似文献   

安徽省两淮地区煤炭资源地质条件分区、分等初步研究   总被引：1，自引：0，他引：1  

姜松  朱文伟  苏永荣  韩锋  孙贵 《中国煤炭地质》2009,(12):64-67

地质变化程度及其所涉及的相关地质条件分类问题是影响勘查工程布置的主要因素。借鉴原国家煤炭部技术咨询委员会1992年所作的《矿井综合评价及分类》所建立的评价指标体系和层次分析评价办法,对两淮地区煤炭资源地质条件进行定性与定量相结合的分区、分等综合评价。首先以两淮地区现有的地质报告成果为依据,以矿区为基本评价单元,选择构造复杂程度和煤层稳定类型作为评价参数,将煤层赋存深度和水文地质条件作为修正参数,应用层次分析法建立起相应的评价指标体系,确定各层次权重系数及相关因素的隶属度,以此建立地质条件分等与煤层连续性、煤层连续性与构造复杂程度及煤层稳定程度之间的对应关系,并确定地质条件分等定量划分标准,在此基础上对两淮地区煤炭资源地质条件作出分区、分等综合评价：淮北煤田的宿县、临涣矿区和淮南煤田的潘谢、淮南定远矿区为地质条件Ⅱ～Ⅲ等区;淮北煤田的濉萧、涡阳矿区和淮南煤田新集矿区为地质条件Ⅳ等区。  相似文献