高能级强夯处理湿陷性黄土设计施工检测应注意的问题   总被引：1，自引：0，他引：1  

詹金林  水伟厚 《岩土力学》2009,30(Z2):457-460

对3 000～15 000 kN.m高能级强夯加固湿陷性黄土的工艺进行了详细地探讨,讨论了设计、施工、检测各个环节可能存在及所需要注意问题,供类似工程优化设计和现场指导施工、检测借鉴。  相似文献   

A sediment record of trace metal loadings in the Upper Mississippi River     

Steven J. Balogh  Daniel R. Engstrom  James E. Almendinger  Charlene McDermott  Jie Hu  Yabing H. Nollet  Michael L. Meyer  D. Kent Johnson 《Journal of Paleolimnology》2009,41(4):623-639

Sediment cores from Lake Pepin, a natural lake on the Upper Mississippi River, reveal the historical trends in trace metal use and discharge in the watershed. Lead-210 dated concentration profiles of trace metals (Ag, Cd, Cr, Cu, Hg, Pb, V, Zn) in sediment cores from throughout the lake generally showed low and stable concentrations prior to settlement (circa 1830), peak concentrations between 1940 and 1975, and substantial decreases thereafter. Whole-lake sediment accumulation rates increased greatly over the period of record, from 79,000 metric tons year⁻¹ prior to 1830, to 876,000 metric tons year⁻¹ during the 1990s. Whole-lake accumulation rates of most trace metals peaked in the 1960s but decreased sharply after that. Sediment and trace metal accumulation rates decreased in the downstream direction, and approximately two-thirds of the sediment and trace metal mass accumulated in Lake Pepin since 1800 was deposited in the upper 30% (by area) of the lake. The dramatic declines in trace metal concentrations and accumulation rates in Lake Pepin sediments since 1970 coincide with increased pollution control and prevention efforts throughout the watershed, including the implementation of secondary treatment at a large municipal wastewater treatment plant upstream. This is one of eight papers dedicated to the “Recent Environmental History of the Upper Mississippi River” published in this special issue of the Journal of Paleolimnology. D.R. Engstrom served as guest editor of the special issue.  相似文献   

磁铁矿的低温磁学性质研究进展   总被引：1，自引：1，他引：0       下载免费PDF全文

肖波  潘永信 《地球物理学进展》2006,21(2):408-415

磁铁矿(Fe3O4)是自然界沉积物和岩石天然剩磁的最主要载磁矿物.本文主要评述低温条件下(2\|300K)磁铁矿的晶体结构特征、Verwey相变以及磁晶各向异性等,重点介绍了两种重要的剩磁随温度变化曲线.最后简单地介绍磁铁矿的低温磁学研究在地学中的应用以及氧化和超顺磁效应对低温磁学性质的影响.  相似文献   

西平公路内社段滑坡稳定性分析与对策研究     

卓万生 《地质灾害与环境保护》2006,17(4):28-32

论述了西平公路内社段东南侧后山高边坡的地形地貌、滑坡发育特征、地质特征和成因机制分析,采用华宁岩土工程勘察软件统计,判定该滑体的稳定性,再通过传递系数法进行稳定性验算,并针对边坡的主要特征和工程实际情况,对该隐患地段的治理方案进行综合比选,提出了较为科学可行、经济合理的防治措施。  相似文献   

Stability analysis and treatment of No.2 dump of Nanfen iron mine     

Yan XU  Lei NIE  Huangping DING  Yin WANG  Jian LIU  Wei LU  Zhenying ZHANG  Xue GONG  Shiwei SHEN 《世界地质(英文版)》2006,9(2)

On the basis of the study on the engineering geological characteristics of No.2 dump of Nanfen iron mine and the analysis of the failure mode of dump landslide, the stability of the present dump, the stability of the dump 20 years later and the stability of double-bench dump are analyzed. Then, the debris flow risk is evaluated by fuzzy mathematics method. Finally, the comprehensive treatment for the dump is suggested. It is concluded that ① In rainy and snowmelt period, the stability would be decreasing sharply when ground water is not drained out in time; ② Double-bench dumping mode will improve stability of the dump little; ③ Debris flow risk is middle danger. The interim debris flow with medium scale may occur. ④ Monitoring, draining and baffling work ought to be well done. ⑤ In order to prevent the damage of landslide and debris flow, three measures are adopted, including setting rockfall net, setting the debris flow barrier and removing the residents.  相似文献   

EU shipping in the dawn of managing the ballast water issue   总被引：2，自引：0，他引：2  

David M  Gollasch S 《Marine pollution bulletin》2008,56(12):1966-1972

After almost two decades of intensified research, regulatory and political activities focussed on the prevention of harmful organisms and pathogen transfers around the world in 2004 the International Convention on the Management of Ships’ Ballast Water and Sediments (BWM Convention) was adopted to provide a common and globally uniform ballast water management (BWM) approach. Nevertheless, regionally different BWM approaches are developing. By now, many countries around the world seem to be aware of the ballast water issue and its management limitations. In the EU, different approaches have been identified at regional and national scales. The first voluntary BWM requirements at the regional level have been introduced by the HELCOM and OSPAR countries, Adriatic countries have prepared a common approach considering a new legal framework for implementation, and some national level requirements have also been identified. However, a common EU wide BWM approach has not yet clearly emerged. In this paper the authors review the BWM approaches developing in Europe, and describe the EU response on BWM. The authors further provide recommendations which may be considered when developing BWM measures in the EU. This contribution focuses on the BWM issue in European seas in light of the EU Maritime Policy and EU Marine Strategy. The Caspian Sea was also considered.  相似文献   

Sonication of bacteria, phytoplankton and zooplankton: Application to treatment of ballast water   总被引：2，自引：0，他引：2  

Holm ER  Stamper DM  Brizzolara RA  Barnes L  Deamer N  Burkholder JM 《Marine pollution bulletin》2008,56(6):1201-1208

We investigated the effect of high power ultrasound, at a frequency of 19 kHz, on the survival of bacteria, phytoplankton and zooplankton, in order to obtain estimates of effective exposure times and energy densities that could be applied to design of ultrasonic treatment systems for ballast water. Efficacy of ultrasonic treatment varied with the size of the test organism. Zooplankton required only 3-9s of exposure time and 6-19 J/mL of ultrasonic energy to realize a 90% reduction in survival. In contrast, decimal reduction times for bacteria and phytoplankton ranged from 1 to 22 min, and decimal reduction energy densities from 31 to 1240 J/mL. Our results suggest that stand-alone ultrasonic treatment systems for ballast water, operating at 19-20 kHz, may be effective for planktonic organisms >100 microm in size, but smaller planktonic organisms such as phytoplankton and bacteria will require treatment by an additional or alternative system.  相似文献   

Analysis of the natural remanent magnetization of rocks by measuring the efficiency ratio through alternating field demagnetization spectra     

T.?KohoutEmail author  G.?Kletetschka  F.?Donadini  M.?Fuller  E.?Herrero-Bervera 《Studia Geophysica et Geodaetica》2008,52(2):225-235

The REM(AF) method is a new tool for the analysis of the origin and alternating field demagnetization coercivity spectra of the remanent magnetization. We applied this method on precambrian Gila diabase sheets from Arizona in order to identify the high coercivity magnetic carrier, and on artificially shocked Rowley Regis basalt from UK in order to analyze the effect of the shock on the natural remanent magnetization. In the Gila diabase the high coercivity magnetic component was identified to be most likely represented by the acicular magnetite (increase in the efficiency ratio in the high coercivity region). In the Rowley Regis basalt, the REM(AF) analysis revealed that comparing to NRM, the shock produced a different distribution of the AF demagnetization coercivity spectra due to the occurrence of the Shock Remanent Magnetization.  相似文献   

西安市固体废弃物卫生填埋场建设中的环境岩土工程问题研究     

孔德泉  万蓉 《岩土力学》2008,29(Z1):583-586

人与环境的和谐共处是当今社会可持续发展的重要内容,面对城市固体废弃物激增所带来的人与环境之间的各种问题,卫生填埋法作为最广泛也是最彻底的固体废弃物处理方法得到了越来越多的关注和研究。卫生填埋场的建设与环境岩土工程领域内的诸多方面密切相关,针对卫生填埋场的建设中涉及到的环境岩土工程问题,在依据已有资料概括介绍国内外相关发展现状的同时,结合西安地区的特点,在填埋场场址和类型选择、废弃物工程性质指标、填埋场防渗处理、填埋场沉降计算和边坡稳定这5个方面对西安地区城市固体废弃物卫生填埋场建设中的环境岩土工程问题进行了论述,提出了相应建议,展望了研究方向。  相似文献   

陕北台塬区深层黄土湿陷性研究及地基处理     

董转运  吕远强 《煤田地质与勘探》2008,36(2):52-54

陕北台塬区深层湿性黄土厚度大,地基处理困难。室内试验表明:该区黄土的湿陷性与其结构、天然含水量、孔隙比、时代成因等因素相关,黄土的湿陷系数由上到下逐渐递减,表明湿陷性随深度增加而逐渐减弱;黄土的含水量和孔隙比分别与湿陷系数呈反相关和正相关关系。提出陕北台塬区深层湿陷性黄土地基处理时,对单位荷重小于250 kPa的建筑物,适宜采用灰土垫层、灰土挤密桩或灰土挤密桩与灰土垫层相结合方案;单位荷重大于或等于250 kPa的建筑物,宜采用桩基础方案。   相似文献