Drainage Performance of Different Sizes Tire Chips used Alone and Mixed with Natural Aggregates as Leachate Drainage Layer Material

Results of compressibility and hydraulic conductivity testing performed under different levels of average vertical stress were used to determine the appropriate tire chips size (in particular aspect ratio) and tire chip—gravel random state mix combination. Proper sidewall treatment was provided to reduce side wall friction up to minimum level and constant head conditions were maintained with appropriate design flow rate. Results showed that tire chips (length 25 mm, aspect ratio 1) mixed with 40 mm gravel in the random state in mixing ratio of 3:1 (ds:dg) was observed to undergo minimum strain, maximum hydraulic conductivity and hence free drainage even under high vertical stress levels. By selecting tire chips of appropriate aspect ratio and optimum mix combination for the construction of drainage layer of MSW landfill leachate collection system lower strain response, higher hydraulic conductivity values and relatively free drainage even under anticipated higher vertical stress levels may be achieved.     

The 14-year Performance of a Compacted Clay Liner used as Part of a Composite Liner System for a Leachate Lagoon

The migration of contaminants through a 2.9 m thick compacted clay liner (CCL) for a landfill leachate lagoon is examined 14 years after construction. The clay liner formed the lower portion of the composite liner system but the geomembrane (GM) was found to have defects that had allowed leachate to migrate between the GM and CCL. Chloride, sodium, potassium, calcium and magnesium pore water profiles through the CCL are examined. It is shown that chloride migrated approximately 1.7 m into the CCL during the 14 years of the lagoon operation, sodium approximately 1.2 m, and potassium 0.7 m. Diffusion and sorption data from laboratory diffusion testing are utilized in combination with a finite layer contaminant transport model to predict field contaminant migration profiles through the composite liner system and to establish the time of ‘failure’ of the geomembrane at sometime between 0 and 6 years after installation. Relatively high sorptive uptake of potassium by the CCL soil is observed from batch testing and diffusion testing with field data suggesting an even larger amount of sorption. It is hypothesized that organic sludge matter at the base of the lagoon is responsible for potassium uptake from the leachate. This field case highlights the importance of the compacted clay liner as part of the composite liner system in acting as a diffusion barrier during the lifetime of the lagoon as well as using relatively non-conservative contaminants such as chloride and sodium to estimate geomembrane ‘failure’ times     

鸟粪石结晶法预处理垃圾渗滤液中高浓度氨氮的研究

利用鸟粪石结晶法预处理垃圾渗滤液中的高浓度氨氮,通过单因素实验和正交实验探讨了pH值、添加剂种类、添加剂比例、反应时间4个因素对氨氮去除率的影响,结合反应过程中的经济成本得出鸟粪石结晶法最佳工艺条件为:pH=9,添加剂为MgC12·6H2O和Na2HPO4·12H2O,n(Mg2+):n(NH4+):n(PO43-)=1:1:1,反应时间15min,氨氮去除率达到90.13%,剩余氨氮在300mg/L以下。通过XRD和ESEM分析,沉淀产物为鸟粪石。实验表明鸟粪石结晶法可以有效去除垃圾渗滤液中的高浓度氨氮,为后续使用生物法处理提供条件,也可以弥补矿物吸附法去除氨氮的不足。可将其与生物法、矿物吸附法等方法组合使用,综合处理垃圾渗滤液。     

铁层柱蒙脱石催化剂微波诱导催化处理垃圾渗滤液

常规生化处理很难使垃圾渗滤液达到市政污水纳管排放标准,或无法稳定排放,必须进行深度处理。本文探索了微波诱导催化用于渗滤液的深度处理,以铁层柱蒙脱石作催化剂,微波辐照下深度处理垃圾渗滤液。结果表明,对初始COD浓度为1100~1300 mg/L的垃圾渗滤液,以铁层柱蒙脱石作为催化剂,在微波功率600 W,辐照时间30 s条件下,经微波诱导催化处理后,COD去除率达到39%。铁层柱蒙脱石催化剂以"卡房"型介孔结构为主,均匀的介孔结构有利于微波诱导催化。     

Statistical Assessment of Unidirectional Propagation of a Leachate Contamination Plume

The leachate produced by the Municipal Solid Waste Landfill of São Pedro da Aldeia (State of Rio de Janeiro, Brazil) flows almost entirely in one direction guided by a natural ditch in the bottom of a gentle valley. This landfill has been in operation with no concern to environmental protection, such as containment systems or leachate drainage and treatment. This inadequate operation causes severe damage to flora, wildlife and local farmers, due to continuous propagation of contaminants in the groundwater. Field and laboratory measurements of ionic concentrations of several contaminants found in the groundwater adjacent the landfill are presented and interpreted in this paper. Several farms are located adjacent to the landfill, comprising about 1,000 inhabitants that use the ground water for personal use and land farming activities. The main purpose of this paper is to assess the environmental hazard to the surrounding properties as the landfill is still in operation. This is accomplished by estimating the maximum distance travelled by the leachate plume based on the statistical interpretation of the measured ionic concentration of several contaminants found commonly in landfills. The main recommendation coming from the statistical assessment is that safe groundwater consumption should be limited to a minimum distance of 400 m from the contamination source, provided that the quality of ground water is continuously monitored while the MSW landfill is still in operation.     

地球微生物过程与潜在烃源岩的形成:钙质微生物岩

钙质微生物岩是各种微生物生命活动引起的特殊的碳酸盐建造, 主要集中发育在前寒武纪及显生宙等重大地质转折期, 在我国华北及华南地区有着广泛的分布.微生物岩中大量微生物化石的存在反映当时的海洋具有很高的初级生产力.明显偏低的钼同位素值显示在前寒武纪相当长的时期里, 海洋底部处于缺氧状态.Th/U值的急剧降低和黄铁矿在浅水台地区的广泛出现显示二叠纪大绝灭后, 海洋环境也同样呈现缺氧的还原状态.高生产力和还原的沉积环境为生物有机质的埋藏及烃源岩的形成创造了条件.前寒武纪及晚泥盆世微生物岩中沥青的发现, 进一步增加了钙质微生物岩作为潜在碳酸盐型烃源岩的可能性.      

Slab Melt as a Potential Source of Profiling Elements of Gold and Heavy Metal Deposits

Spatial/genetic control by slab magma products at gold deposits is shown in this paper by the example of granitoids in the Ust’-Kara area of the Eastern Trans-Baikal Region. The investigation performed makes it possible to take a fresh look at the problem of metal sources in the East Trans-Baikal gold deposits and to relate their formation to material flow from the oceanic lithosphere in the subduction zone, material conservation within the subcontinental mantle, and possible remobilization under large tectonic reconstructions.     

Performance evaluation of ultrafine cement as a grout for reservoir impermeability improvement

Acta Geotechnica - Although Ordinary Portland Cement (OPC) has been widely used as one of the significant grouting materials, there are many drawbacks to its application in the field. In this...     

低、中煤阶煤层气地质选区评价体系

地质选区是煤层气勘探与开发的基础工作。我国低、中煤阶煤层气资源丰富,完善煤层气地质选区评价体系十分重要。笔者对影响煤层气勘探开发潜力的各种因素进行了综合分析,确定了主要影响因素,并利用多层次模糊评判法建立了低、中煤阶煤层气地质选区评价体系。研究表明:处在勘探初期的低煤阶煤层气选区的主要影响因素为煤层的生气潜力、储集性能和煤层气的保存条件;进入开发期的中煤阶煤层气选区的主要影响因素为煤层气的资源条件、赋存条件和开发条件。通过实例应用,彬长区块低煤阶煤层气勘探区可分为6类,一类区主要分布在亭南—大佛寺矿区以及雅店矿区北部区域,向周围煤层气勘探潜力降低;柳林区块中煤阶煤层气开发区可分为5类,一类区主要分布在东南部CLY井组和中北部FL-EP1井区的东北侧区域,北部聚财塔断层附近最不利于煤层气开发。     

Biogenic Graphite as a Potential Geomarker—Application to Continental Reconstructions of Pan-African Gondwana Terrains

Graphite is present in nature in several forms. Genetically they may be broadly classified as biogenic and abiogenic. The biogenic forms are those that are clearly derived from an organic precursor while the abiogenic or inorganic forms are more complex from the point of view of their origin, nature and geological relations.As a geomarker, biogenic graphite has certain advantages. It is easily recognized and shows different degrees of crystallinity depending on the relative grades of metamorphism it had undergone. Once it attains a certain degree of crystalline order, it does not revert to a lower state even under changing metamorphic conditions, thereby making it a good mineral geothermometer. It is also found in specific, restricted geological environments and is therefore useful as a boundary marker of ancient sedimentary terrains.These special characteristics of the biogenic type of graphite can be effectively used to trace sites of sedimentary basins and subsequent ocean closures that may have resulted in geosutures. Studies of the Pan-African terrains of the Gondwana crustal fragments as exemplified by the sutures of the Mozambique Belt running through East Africa, Madagascar, Sri Lanka and Antarctica illustrate this point. A further example comes from the Mashan Group of East China, one of the most productive graphite - bearing regions of the world.     

Theory of Filtration in a Double Porosity Medium

Doklady Earth Sciences - This paper defines a generalized mathematical model of filtration in a double porosity medium, taking into account recent ideas on liquid and gas flow in rocks with an...     

浙江省中小型水库水文自动测报系统设计思路

利用浙江省较为发达的通信资源，采用GSM、PSTN通信信道建立浙江省防汛水情信息短信通信平台，提高水情信息传输的快速、安全可靠性及实现信息共享；采用斜井式水位计解决已建水库建设水位台施工困难及投资高的问题，使建设工作更加简便，投资更为节省。     

Performance of a pickax

Summary Single and multiple impact tests were conducted with a commerically available 3.58 kg pickax with a 60° conical tip and a 30° wedge tip in the input energy range from 1.01 to 59.4 J. Five target materials were employed: (1) 2024-0 aluminum, (2) diorite, (3) sandstone, (4) cement-sand, and (5) green shale. Force and penetration data were collected using strain gages and a non-contact displacement probe. It was found that when the impact process involves cracking and chipping, the maximum penetration was linearly proportional to the input energy and the forcepenetration relation exhibited non-linear characteristics. When the impact process does not involve cracking or chipping, the penetration was related to the square root of the input energy and the force-penetration relation exhibited a nearly linear relation. Thus, empirical models involving a linear spring resistive force or a constant resistive force were found to reasonably describe the penetration and input energy data. In addition, an analytical model involving a pickax mass inertia term and a piecewise linearized force-penetration function was constructed that portrayed the force and penetration histories. Good results were obtained for both conicaland wedge-tip cases. From the multiple impact tests it was found that the efficiency of the pickax operation decreases by about 50 to 60 percent after ten impacts, suggesting that the impact point be moved in order to obtain an improved performance.     

高活性粉煤灰注浆材料性能和应用

高活性粉煤灰注浆材料是以工业废料－粉煤灰为主体,配合其它具有胶凝增强和提高早期强度的外掺料,以及能改善浆液性能使之满足注浆施工作业要求的外加剂,经特殊加工而成的一种新型注浆材料。该材料与普通硅酸盐水泥用于注浆工程相比有流动性好、凝结时间适当、抗压强度较高、结石率高的特点,经在静压注浆和高压旋喷注浆工程中的初步应用,取得了较好的效果。     

地热资源潜力评价——以鄂尔多斯盆地部分地级市和重点层位为例

针对鄂尔多斯盆地地热资源储量认识不统一、浅层地热能开发方式不明确、地热资源有利层位及有利区划定有分歧的3个问题,采用不同的评价方法分别对鄂尔多斯盆地水热型地热资源、浅层地热能和干热岩型地热资源进行了潜力和远景评估,结合地热资源的开发利用方式和效益对鄂尔多斯盆地的地热资源进行了综合分析。分析结果表明,鄂尔多斯盆地地热资源相对丰富,盆地内部分层位水热型地热资源量折合标准煤249.4×108 t,地热资源年可开采量折合标准煤748.1×104 t;7个地级以上城市浅层地热能资源年可采量折合标准煤281.2×104 t;干热岩潜力资源量折合标准煤16.63×1012 t。盆地内部地热资源有利区主要分布于榆林-横山-靖边及子长-安塞-延安一带。目前鄂尔多斯盆地0~200 m浅层地热能开发主要以地埋管地源热泵为主,地下水源热泵为辅。200~6000 m中深层地热资源开发主要以深埋管换热方式和采灌结合方式开采。开发地热能,节能减排效果明显,值得大力推广。     

Performance of flexible emergent vegetation in staggered configuration as a mitigation measure for extreme coastal disasters

The performance characteristics of emergent greenbelt vegetation has received considerable attention in the recent years, post-Great Indian Ocean Tsunami (26 December 2004). In the present work, a comprehensive laboratory study on the hydraulic resistance characteristics due to a group of slender cylindrical members representing flexible plantation has been carried out in a laboratory open channel. The model stem groups comprised of individual members of different sizes and concentrations in staggered configuration. The sizes and concentrations were chosen in such a way that they would fall into the practical ranges of vegetations in coastal forestry. The results indicate that the flow resistance varies with stem concentration, stem diameter and elastic properties of the individual members and the flow velocity. Based on the results, the Darcy friction factor, f, for various flow and vegetative parameters was derived. A new empirical equation is proposed for evaluating f for partially submerged vegetation in staggered configuration for a wide range of depths of flow in relation to un-deflected plant heights. It is expected that the f thus determined will be useful in modelling the shallow flows using shallow water equations.     

Effect of Water and Leachate on Hydraulic Behavior of Compacted Bentonite,Calcareous Sand and Tuff Mixtures for Use as Landfill Liners

Compacted soil–bentonite liners, consisting of a sandy soil mixed with bentonite as backfill, are used extensively as engineered barriers for contaminant containment. This paper studies the valorization of local materials containing calcareous sand, tuff obtained from Laghouat region (in the South Algeria), to associate with bentonite in order to improve their hydraulic characteristics for use as landfill liner material. Firstly, a geotechnical characterization of mixtures chooses from a fixed percentage to 10% bentonite and different percentages of calcareous sand and tuff so that they are complementary to 90% by not 10%. Thereafter, the determination of saturated hydraulic conductivity at falling-head permeability (K_v) and oedometer (K_id, indirect Measure) tests of all compacted mixtures at Optimum Normal Proctor have been carried out using both permeates by tap water and a landfill leachate in order to simulate long-term conditions. The results showed that the saturated hydraulic conductivity of tap water is relatively lower than the one saturated by leachate in the falling-head test, unlike the oedometer test. The B₁₀CS₂₀T₇₀ mixture has satisfied the hydraulic conductivity criterion of bottom barriers (i.e. water permeated: k_v20° = 1.97 × 10^?9 and k_id from 7 × 10^?9 to 1.83 × 10^?10 < 10^?9m/s; leachate permeated: k_v20° = 2.91 × 10^?9 and k_id from 7 × 10^?9 at 1.44 × 10^?10 < 10^?9 m/s). Finally, a comparison between direct measurements of the saturated hydraulic conductivity by triaxial (K_d) test and oedometer test (K_id) in the range of effective stress applied 100–800 kPa led to propose equations of correlations between these two methods. In conclusion, adopted formulation B₁₀CS₂₀T₇₀ perfectly meets the regulatory requirements in force and constitutes an economic product based on available local materials for engineers barriers.     

中温UBF与UASB两相厌氧系统处理垃圾渗滤液的实验研究

针对石碑岭垃圾场渗滤液水质特性,采用以高效生物陶粒为填料的UBF反应器作酸化相,以UASB反应器作甲烷相的两相厌氧系统进行了处理垃圾渗滤液的实验研究.实验结果表明:在系统进水CODCr和BOD5质量浓度分别为3 887 mg/L和819 mg/L,UBF与UASB的HRT分别控制在10.3 h和61.7 h时,CODCr和BOD5总去除率分别为85.4%和90.1%,UBF酸化率达42.9%,BOD5/CODCr比值由0.21提高到0.39.     

An Appraissal of the Performance of Geosta as a Stabilising Agent for Deltaic Laterite in Sub-Base Construction

This study was prompted by the massive and unprecedented failure experienced within a very short time after construction of “Ada-George Road” which had deltaic lateritic sub-base stabilised with undisclosed but most probably uncontrolled (scientifically) proportions of cement and geosta (a relatively new chemical stabiliser). Samples of the deltaic laterite were taken from two of the borrow-pits within Port Harcourt metropolis from which materials were quarried for the construction of the sub-base. The results showed that although geosta addition to deltaic laterite mixed with cement gives considerable improvement on the strength of the resulting mixture, this stabilisation is only effective at very low geosta content not exceeding 2% depending on the optimum geosta content (OGC) which in turn is a function of the percentage of fines of the soil. But the Ada George road project appeared to be politically rather than scientifically motivated. Consequently, the OGC must have been grossly exceeded in the construction of this geosta stabilised sub-base. As a result, the as-built CBR must have been much lower than expected hence the massive failure that resulted. Even for 2% geosta content, this composite stabilisation was also found to be most effective at 4% cement content.     

Paleoearthquake Features as Indicators of Potential Earthquake Activities in the Karameh Dam Site

Prehistorical earthquake induced features, such as faults, folds, fissures, and slumps have been discovered during the Karameh dam construction. The dam is located close to the plate tectonics boundary formed by the active Jordan Valley Fault. Of most importance are those known as the fold-type deformations ``décollement type of structure' which are well preserved in the laminated Lisan formations. These features show that historical moderate to strongly sized earthquake activities are likely to have been originated in the vicinity of the dam site. Such features may well provide valuable information for identification of areas of highly strong earthquake regions.