Amelioration of groundwater nitrate contamination following installation of a central sewage system in two Israeli villages

This study traces both the long-term deterioration of the ground water supply in two neighboring villages that had relied upon cesspits/cesspools for waste disposal, as well as the subsequent progressive improvement to original water quality levels. The rapid improvement is attributed to the replacement of the cesspits by a central sewage disposal network. In each of the villages of Kefar Bara and Kefar Kassem, a single, relatively deep, community well supplies drinking water. These wells were drilled into the underlying carbonate Judea Group aquifer that initially provided very high quality potable water. Over time, large increases in the nitrate contamination, reaching to as high as 67 mg/L nitrate, paralleled the population growth. The higher dissolved nitrate concentrations were also marked by enrichments in the δ¹⁵ N (approximately +8 ‰_(air)) values above those of the surrounding and regional uncontaminated background δ¹⁵ N values (in the range of +3 to +6 ‰ _(air)). Within several years after the cesspit disposal was terminated the nitrate values declined to concentrations that were reported (approximately 25 mg/L-NO₃) decades prior, when the water quality monitoring had just commenced. This study demonstrates not only how water quality can degrade but also how it can be restored once the problem is identified and countered. This simple method of ameliorating a water quality problem that was tending towards reaching serious proportions would seem to be quite efficacious for any area lacking economic alternative water resources.     

Shear strength behaviour of compacted clayey soils percolated with an alkaline solution

In the French model of deep nuclear wastes repositories, the galleries should be backfilled with excavated argillite after the site has been filled. After thousands of years, the degradation of the concrete lining of the galleries will generate an alkaline solute (pH > 12) that would circulate through the backfill. The goal of this paper is to describe the impact of such solute circulation on the properties of compacted argillite. Since additives (bentonite, sand or lime) are often introduced in the remoulded argillite for the backfill, such mixtures were also studied. Saturated-portlandite water was circulated through compacted samples for 3, 6 and 12 months at 60 °C. The shear strength behaviour of the samples was determined with triaxial tests. The microstructure of the samples was analysed via mercury intrusion porosimetry tests and scanning electron microscopy. The results showed that the influence of the alkaline fluid on the properties of the argillite is a function of the nature of the additive. In the case of the calcareous sand, no major changes were observed. The pure argillite underwent a slight decrease in its cohesion due to limited dissolution of its clayey particles. Conversely, intense alteration of the bentonite–argillite mixture was observed, and the shear strength behaviour was modified. Lime addition improved the mechanical characteristics of the argillite.     

实测地层剖面参数的电算化应用方法

针对剖面数据处理一直沿用手工计算和手工核算的传统方法的问题,本文提供了以下电算化方法,它扬弃了繁冗的手算步骤,提高了计算的准确度,同时还便于检查核算。     

郑州--少林寺高速公路采空区治理对策

郑州—少林寺高速公路穿越两个煤矿采空区,为保证高速公路的安全运营,必须对采空区进行治理。本文分析了采空区特征和采空区对郑州—少林寺高速公路的危害．在此基础上提出采用全充填法对采空区进行治理的对策．并实施了治理工程。经检测,达到了设计所要求的处理效果。     

高放废物深地质处置库预选场址的古温度环境

填隙矿物的流体包裹体研究与矿物的同位素地球化学研究可较好地揭示高放废物深地质处置库预选场址的深部热环境及古地下水热历史。中国高放废物深地质处置库第一个预选场深部花岗岩内填隙矿物的同位素、矿物学以及流体包裹体研究结果显示,甘肃北山地区花岗岩深部至少存在两种环境：浅部花岗岩(0～150m)填隙方解石的δ^18O=-18．2‰～-15．8‰(PDB),δ^13C=-9．5‰～-8．4‰(PDB),包裹体的均一温度(th)为140～160℃,包裹体的冰点温度为-2．5～-1．5℃,地下水可能以大气降水成因为主,且可能混合了盆地卤水并与花岗岩反应,形成温度、盐度(2％～5％,NaCleq)均较低的地下水;在350～550m区段内(深部花岗岩),其δ^18O值为-32．6‰～-17．6‰(PDB),δ^13C值为-10．5‰～-6．2‰(PDB),流体包裹体的均一温度较其上部的稍高,为160～190℃,而其冰点温度则较低,为-4～-3．2℃(盐度5％～8％,NaCleq),地下水类型为大气降水与盆地古卤水的混合,以大气降水为主。石英的氧同位素组成和计算的古地下水氧同位素组成则进一步表明,花岗岩深部(350～550m)也存在两种温度环境：较低温度(140～160℃)、较高盐度(5．5％～8％,NaCleq)的地下水;较高温度(220～240℃)、较低盐度(3％～5．5％,NaCleq)的地下水,其地下水类型为大气降水和与花岗岩平衡的卤水。     

高放废物地质处置数据资源集成开发进展

数据资源是高放废物地质处置库选址、安全评价、工程建设等研发的重要基础,该领域数据具有典型的大数据特性,其开发利用是一项长期、系统的科学工程。文章对我国高放废物地质处置数据资源集成开发策略、方法和现状进行了简要介绍,阐述了高放废物地质处置研发过程中产生的各类科学数据的具体特性,提出建立我国高放废物地质处置大数据平台的规划设想,重点介绍了处置库预选区地学信息集成开发现状。     

基于混合架构的地学信息数据库管理系统的实现

文章在已经建设完成的高放废物地质处置地学信息数据库的基础上,采用B/S和C/S混合架构,基于.NET平台和JAVA Web等编程技术,在完成基础GIS系统、多源数据集成技术和数据应用表述功能等基础开发工作的前提下,实现了地学信息数据库管理系统所有功能模块的集成,尤其是专业数据管理服务和全文检索服务两大重要服务功能的实现,为高放废物地质处置领域科研数据管理与二次利用提供了便利的基础支撑。     

高放废物地质处置地下实验室新场候选场址三维地质建模

在新场研究区现有资料分析和解译的基础上,对岩体单元和断裂分别进行建模,然后将两个模型合并进行插值计算,建立了高放废物地质处置地下实验室新场候选场址的三维地质模型。基于模型开展了一系列三维剖切、任意开挖、钻孔设计等可视化分析应用研究,全面真实地揭示了候选场址周围深部地质环境特征,并筛选出半径约1km的区域用作地下实验室的候选场址,为我国高放废物地质处置项目的后续工作中地质分析与工程设计提供有益参考和技术支持。     

A study on how to couple thermo-hydro-mechanical behaviour of unsaturated soils: Physical equations,numerical implementation and examples

This paper describes a thermo-hydro-mechanical framework suitable for modelling the behaviour of unsaturated soils. In particular, this paper focuses on bentonite clay subjected to a thermo-hydro-mechanical load, as in the case of nuclear waste engineering barriers. The paper gives a theoretical derivation of the full set of coupled balance equations governing the material behaviour as well as an extended physical interpretation. Finally, a finite element discretisation of the equations and number of simulations verifying their implementation into a custom finite element code is provided. Some aspects of the formulation are also validated against experimental data.