非饱和膨润土的有效热传导特性模型     

周嵩  陈益峰  张勤 《岩土力学》2014,35(4):1041-1048

膨润土缓冲材料热传导特性的研究,对于高放废物深地质处置系统的安全评价至关重要。基于串、并联原理,通过将土体孔隙划分为与固相基质并联和串联两部分,提出了考虑矿物成分、颗粒亲水性、孔隙率及饱和度等因素的非饱和膨润土有效热传导系数的4种预测形式,建立了基于4种形式线性组合的有效热传导特性预测模型。详细讨论了模型参数的确定方法,并讨论了孔隙率、饱和度和孔隙结构、颗粒亲水性等因素对土体有效热传导特性的影响。基于MX-80膨润土和高庙子膨润土热传导特性试验成果,对模型的预测性能进行了验证。结果表明,由于膨润土颗粒尺寸较小且具有亲水特性,孔隙内的空气与水宜采用并联描述。研究成果对于非饱和膨润土的导热性能以及工程屏障系统的THM耦合数值模拟研究具有一定的参考价值。  相似文献   

Extraction of High Purity Bischofite (MgCl2.6H2O) from Left Over-Resiudal Bittren, Lake Quroun, Egypt     

Elsheikh RAGAB 《《地质学报》英文版》2014,88(Z1):363-365

正1 Introduction The left-over(residual)brines often in industrial facilities is disposed back to the sea or in dump areas e.g.abundant salt mines in other cases.Dumping into the sea  相似文献   

Best of two worlds? Towards ethical electronics repair,reuse, repurposing and recycling     

《Geoforum》2017

International trade of discarded electronics (e-waste) has become a matter of concern over the last decade because of the actual and potential harms associated with their hazardous materials. An initiative under the aegis of the UN called the Best-of-Two-Worlds (Bo2W) philosophy is one solution to the e-waste problem that has gained some traction. Our dual purpose is to examine the ethical grounds of Bo2W and to propose an alternative program for action. We call this alternative ethical electronics repair, reuse, repurposing, and recycling (EER4). To explore the ethical grounds of Bo2W and to articulate EER4 as an alternative, we draw on notions of ethics, technology, and organization developed in science and technology studies (STS) and diverse economies literatures while empirically we explore a mixed methods case study of a small recycling firm in northern Mexico. Conceptually and empirically, our analysis points to a need for a richer imagination of the possibilities for economic action oriented toward managing discarded electronics. More broadly, our findings may act as a reminder that the space between use and discard proliferates the literal and figurative resources for enriching the imagination and enactment of diverse economic possibilities via the action of repair, reuse, repurposing, and recycling.  相似文献   

Consolidation settlement properties of seashore landfills for municipal solid wastes in Korea     

Wooseok Bae 《Marine Georesources & Geotechnology》2017,35(2):216-225

The large amount of wastes is generated in metropolitan area where population is heavily concentrated. As a result, treatment of wastes became a social problem and geotechnical problems related to landfill have emerged in Korea. Settlement behavior of waste landfill is similar to behavior of peat that possesses relatively small time-dependent secondary compression alongside large initial compression. A number of researchers published their own settlement computations. However, accurate computation method for waste-reclaimed landfill has yet to be determined as the settlement mechanism is very complicated. Hence, it is important to examine the accurate settlement behavior of reclaimed ground by comparing the material properties from laboratory test and field monitoring and comparing the results with the theoretical equation. This study determines the consolidation coefficients according to the change of organic contents through the total volume reduction in fresh waste layer and initial void ratio change and examines the feature of settlement in each load stage. Moreover, the article attempts to investigate the characteristics of consolidation of the relevant reclaimed landfill and to determine the suitability of the equation by comparing the variables in theoretical equations obtained from the laboratory test and field monitoring. Moreover, to verify the compression characteristics of the waste-reclaimed landfill upon loading, consolidation test results were analyzed to conduct index study on the consolidation characteristics of the waste-reclaimed landfill.  相似文献   

加筋土挡墙静载模型试验及其力学性能研究     

李丽华  石安宁  肖衡林  胡智  杨俊超  余长道 《岩土力学》2018,39(12):4360-4368

为研究加筋土挡墙在墙顶荷载作用下土体受力和变形形态,通过改变筋材层数、筋材长度和替换加筋材料等方式对加筋土挡墙进行了4种工况的模型试验。对4种工况下的加筋土墙体内竖向土压力、墙面水平位移、墙顶竖向位移和筋材应变等进行对比研究。研究表明,挡墙上部竖向土压力增长较快且各层竖向土压力最大值由加载点下部向墙面处移动;墙顶荷载超过130 kPa时,由于不均匀沉降,第5层筋材对应墙面处有向内收缩趋势,墙面水平位移最大值大约在上三分点位置;整个加载阶段,筋材总体应变值增幅不大且远小于筋材设计应变峰值;增加挡墙内筋材层数和增加筋材长度均可提升挡墙各方面性能,但增加筋材层数提高效果要优于增加筋材长度;使用废旧轮胎代替单向格栅进行加筋可有效提高挡墙整体性能,分散超载引起的附加应力,有效减小墙面水平位移和墙顶竖向位移。  相似文献   

Nuclear waste isolation: an urgent international responsibility     

W. S. Fyfe 《Engineering Geology》1999,52(3-4):159-161

The isolation of nuclear wastes for at least thousands of years is an urgent world problem. It is an international problem, for in many nations with such wastes their geology is not suitable for long-term isolation.

A lead geo-question involves which are the best host rocks, with guaranteed long-term low permeability and the best ion-exchange, redox systems for the capture, retention, of the most dangerous nuclides. In general mud rocks on land or the sea floor must be considered.  相似文献   

Mathematical modelling of groundwater flow at Sellafield, UK     

Chris McKeown  R. Stuart Haszeldine  Gary D. Couples 《Engineering Geology》1999,52(3-4):231-250

Sellafield in West Cumbria was a potential site for the location of the UK's first underground repository for radioactive, intermediate level waste (ILW). The repository was to lie around 650 m beneath the ground surface within rocks of the Borrowdale volcanic group (BVG), a thick suite of SW dipping, fractured, folded and metamorphosed Ordovician meta-andesites and ignimbrites. These are overlain by an onlapping sequence of Carboniferous and Permo-Triassic sediments. In situ borehole measurements showed that upward trending fluid pressure gradients exist in the area of the potential repository site, and that there are three distinct fluid types in the subsurface; fresh, saline and brine (at depth, to the west of the site). Simulations of fluid flow in the Sellafield region were undertaken with a 2D, steady-state, coupled fluid and heat flow simulation code (OILGEN). In both simplified and geologically complex models, topographically driven flow dominated the regional hydrogeology. Fluids trended persistently upwards through the potential repository site. The dense brine to the west of the site promoted upward deflection of topographically driven groundwaters. The inclusion in hydrogeological models of faults and variably saline sub-surface fluids was essential to the accurate reproduction of regional hydraulic head variations. Sensitivity analyses of geological variables showed that the rate of groundwater flow through the potential repository site was dependent upon the hydraulic conductivity of the BVG, and was unaffected by the hydraulic conductivity of other hydrostratigraphic units. Calibration of the model was achieved by matching simulated subsurface pressures to those measured in situ. Simulations performed with BVG hydraulic conductivity 100 times the base case median value provided the “best-fit” comparison between the calculated equivalent freshwater head and that measured in situ, regardless of the hydraulic conductivity of other hydrostratigraphic units. Transient mass transport simulations utilising the hydraulic conductivities of this “best fit” simulation showed that fluids passing through the potential repository site could reach the surface in 15 000 years. Simple safety case implications drawn from the results of the study showed that the measured BVG hydraulic conductivity must be less than 0.03 m year⁻¹ to be simply declared safe. Recent BVG hydraulic conductivity measurements showed that the maximum BVG hydraulic conductivity is around 1000 times this safety limit.  相似文献   

Role of carbonates in mitigation of metal release from mining waste. Evidence from humidity cells tests   总被引：7，自引：0，他引：7  

H. Holmström  J. Ljungberg  B. Öhlander 《Environmental Geology》1999,37(4):267-280

 Leaching of two contrasting types of sulphidic tailings in humidity cells has been performed. The release of heavy metals and the oxidation rate have been studied. Tailings from the Laver mine contain a few percent sulphides and lack carbonates, whereas tailings from the Stekenjokk mine are both sulphide- and carbonate-rich. The results showed that in the leachates from the Laver samples, the metal concentrations increased and pH decreased with time, indicating an increased oxidation rate. In the Stekenjokk samples, pH remained high during the experiment, thereby keeping the metal concentrations low in the leachates. The oxidation rate also decreased with time, probably due to Fe-hydroxide coatings on sulphide surfaces. The results show that addition of carbonates and the maintenance of a high pH not only reduce the solubility of heavy metals, but also decrease the oxidation rate of sulphides. Received: 20 January 1998 · Accepted: 2 April 1998  相似文献   

硫酸厂废水对湖泊水环境的影响预测及防治对策研究          下载免费PDF全文

程胜高  张聪辰  李国斌  吴登定 《地球科学》1999,24(3):325-328

硫酸工业废水排放对水环境的影响及防治具有十分重要的意义,为评估大冶市拟建硫酸厂对湖泊水环境的影响,采用类比分析,湖泊自净模式计算等方法对拟建厂水洗和酸洗两种工艺流程下排放的废水及典型污染物Ａｓ与Ｆ的排放量进行了估算,并着重就水洗流程废水对湖泊水环境的影响进行了预测,结果表明,水流洗程对湖泊水环境的影响较大,并造成排放口附近的严重污染;建议采用酸洗流程,提高矿产品位及其综合措施来减少其对湖泊水环境扔  相似文献   

天然沸石在畜禽饲养及粪便污染治理中的应用研究   总被引：9，自引：0，他引：9  

韩成  叶大年  鲁安怀  姚光光  严永鑫  刘成国  唐军利  朱桂珍  韩玉璞 《岩石矿物学杂志》1999,18(4):340-347

在畜禽饲料中添加适量的河北省赤城所产的沸石矿粉,不仅可使肉蛋疸有所增加,提高饲料率,降低生产成本,而且可降低畜禽舍内的有害气体含量,改善饲养人员的劳动环境,并有僧于畜禽健康。采用人工干清粪、沸石－好氧细菌发酵治理畜禽粪便工艺,具有较大的技术和成本优势,可以改善饲养场的周边环境,对于水资源的保护和利用具有重要意义,为畜禽粪便的污染治理与商品化生产提供了新的途径。  相似文献