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1.
大部分垃圾填埋场选有低洼、底部由砂组成的地带,开发利用砂土作为填埋场防渗衬垫具有十分重要的意义。本文介绍了砂土中渗和膨润土添加２剂对砂土衬垫防渗性能改善的研究方法及研究结果。 相似文献
2.
土工合成材料粘土衬垫(GCL)与土工膜(GM)形成的复合衬垫在垃圾填埋场中的应用日益广泛。我国规范中允许在特殊情况下用GCL代替压实粘土(CCL)做垃圾填埋场的衬垫,但是对于“特殊情况”没有明确说明。本文采用数值方法对复合衬垫中无机污染物的对流和扩散进行了计算,从衬垫底部污染物通量和累积量两个角度对GCL复合衬垫和CCL复合衬垫阻滞污染物运移的效果进行了比较,分析两种复合衬垫的等效性,并研究了GCL复合衬垫的适用范围。结果表明,当渗滤液水头较高时,GCL复合衬垫体现出其优势。 相似文献
3.
压实黏土衬垫是填埋场等环境岩土工程中常用的屏障材料,其厚度和渗透系数是主要的设计参数。考虑渗透系数的变异性,用衬垫底部污染物相对浓度和通量等指标分析了设计参数对衬垫有效性的影响。研究表明,渗透系数的变异性对衬垫性能有很大的影响：当衬垫厚度较小或渗透系数均值较大时,衬垫底部出现高浓度（接近于1）的概率很大,这个浓度区间可能比相对浓度的均值高很多,对周围环境污染有较大的威胁。从非反应性溶质的运移来看,我国规范中对衬垫厚度和渗透系数的规定是合理的。相对于污染物的通量,厚度和渗透系数对衬垫底部相对浓度的影响更为显著,相对浓度更适合作为评价衬垫性能的指标。 相似文献
4.
从污染控制的角度出发,提出了垃圾填埋场底部防渗衬垫的等效性原则,在此基础上提出“替代”衬垫的设计方法,并利用压实黄土底衬作为实例进行了说明。研究结果表明,穿透衬垫的污染物累积量可以作为设计替代底衬的主要依据。 相似文献
5.
最新研究表明,多孔介质中溶质运移现象受化学渗透和土壤表面电荷的多重影响。随着城市化进程的加快,卫生填埋场衬垫系统的长期安全性和淤泥脱水问题也愈加严重。为了综合研究水头,电场和化学渗透等物理作用对离子在土壤介质中迁移特性的影响,建立了一个新的多场耦合模型。该模型用有限元法取得数值解,并且利用移动边界成功实现了对淤泥脱水和填埋场衬垫系统中水溶液和化学溶质迁移问题的数值模拟。对于衬垫系统而言,化学渗透现象和渗透电势两者均可减缓溶质击穿土层的时间,有助于延长衬垫的工程寿命。对于淤泥脱水问题的分析结果表明,水力渗透系数和电渗系数分别是主导压滤式和电渗式脱水处理的主要变量。孔隙淤堵是压滤脱水中最主要的问题,土工织物表面所积聚的滤饼会导致水流量急剧下降 相似文献
6.
老垃圾填埋场竖向扩建时垃圾堆体的不均匀沉降控制是中间防渗衬垫系统设计的基础,正确计算和分析垃圾堆体的不均匀沉降将是老填埋场竖向扩建时成功与否的关键。研究了竖向扩建时垃圾不均匀沉降,并介绍了不均匀沉降的计算方 法,结合工程实例对老填埋场竖向扩建时垃圾不均匀沉降影响进行了分析,从工程技术角度提出了相应的解决方案。 相似文献
7.
有机污染物在垃圾填埋场复合衬垫中有两种不同的运移方式:土工膜上缺陷处污染物的运移和完好复合衬垫中污染物的扩散。文章分别用有限差分法和解析法对两种方式下污染物的累积量进行计算,分析了两种方式对有机污染物运移所做的贡献。研究表明:GCL(人工合成材料粘土衬垫)复合衬垫以有机污染物在完好复合衬垫中的扩散为主,可以忽略缺陷处污染物的运移;而CCL(压实黏土衬垫)复合衬垫中两种运移方式所做的贡献在同一数量级,需要考虑两种方式的共同作用。在GCL复合衬垫下铺设粘土层能有效改善GCL复合衬垫对有机污染物的阻止效果。 相似文献
8.
介绍了国外在垃圾填埋场衬垫层、覆盖系统 (帽子 )、垂直隔离墙及土工布等方面的最新进展. 相似文献
9.
对填埋场振动台模型试验进行非线性数值分析,并与试验结果相互补充、印证,进一步考察填埋场的地震响应规律。研究表明,特殊的夹层结构形式导致水平地震作用下城市垃圾填埋场存在两个主要的响应频率,在这两个主要频率附近模型顶部取得峰值加速度响应;不考虑其他因素的影响,填埋场防渗层的地震永久位移与输入地震动的水平位移振幅近似呈正比关系;坡比是影响填埋场覆盖层和衬垫层永久位移最主要的因素。 相似文献
10.
针对垃圾填埋工程中复合衬垫的界面抗剪特性,利用改进的叠环式单剪仪,对由砂土-无纺型土工布-土工网格-土工膜-夯实粘土组成复合衬垫进行了整体剪切试验研究。重点讨论了复合衬垫整体单剪试验的应力-位移曲线、相同剪切应力下各个界面的位移大小与变化特征和强度特性。研究结果表明：复合衬垫整体单剪试验的应力-位移曲线在低法向应力试验中没有呈现明显的软化特征,在高法向应力试验中有硬化现象;随法向应力增加剪切破坏面会发生转移;目前常用的把复合衬垫拆分为单个界面进行研究来确定最危险界面的方法不能够正确地反映填埋场中的复合衬垫在加载过程中的衬垫单元的实际受压变形情况和在剪切变形过程中最危险破坏面转移的情况;复合衬垫界面的抗剪强度包线呈现双曲线性质。 相似文献
11.
结合生活垃圾PTH蠕变方程式中的相关参数,依据重庆市长生桥垃圾卫生填埋场的填埋工艺和填埋方案,得出填埋历程与填埋高度的关系曲线。通过与土压缩理论计算方法相比较发现,土压缩理论中参数选取主要以经验为主,假设条件也与实际情况不符,而PTH蠕变模型中各参数均可由室内压缩蠕变试验得出,依据充分。计算表明,重庆市长生桥垃圾卫生填埋场在填埋过程中产生的沉降达25.72%,在容量估算中如果忽略这一数据则会对填埋场的经济性分析产生一定影响。 相似文献
12.
论述了国内外城市卫生填埋场相关的岩土工程问题及其研究现状,包括卫生填埋场填埋体物理力学性质、卫生填埋场的防渗系统和边坡稳定等一系列岩土工程问题,在此基础上初步探讨了我国城市卫生填埋场相关岩土工程问题的发展前景。 相似文献
13.
The study of landfill sites is one of the most important studies in landfill engineering, and the landfill site selection
involves combination of engineering, science, and politics. This paper describes a comprehensive hazardous waste landfill
site selection methodology with the combined utilization of geographic information system and multiple criteria analysis methods,
as applied to the Zanjan province in Iran. The six main data categories that were used are geological/engineering geological,
geomorphological, hydrological/hydrogeological, climatological, pedological, and social/economical criteria, which included
31 input layers in total. A suitability map for hazardous waste landfilling was prepared for study area with five classes
from most suitable to completely unsuitable. Finally, out of the three sites, one site was selected which was chosen by the
local authorities. Our work offers a comprehensive methodology and provides essential support for decision-makers in the assessment
of hazardous waste management problems in Zanjan province in I.R. Iran and other developing cities in other countries. 相似文献
14.
This study draws attention to the fact that natural processes can mobilize thallium （Tl）, a highly toxic metal, which may enter the food chain with severe health impacts on the local human population. A rural area having independent Tl mineralization in southwestern Guizhou, China, was chosen for a pilot study. Tl contents of soils extracted by HNO3 in the study area range from 35-165 mg/kg in soils from the mining area, 14-78 mg/kg in alluvial deposits downstream, and 〈0.2-0.5 mg/kg in soils from the background area. Tl contents in ammonium acetate EDTA-extracted fraction are 0.013-1.3 mg/kg, less than 1% of concentration in HNO3-extracted fraction. The amounts of Tl in NH4Ac-extracted fraction were thought to be more exchangeable and bioavailable, i.e., immediately available to plants and/or available to plant roots over a period of years. Tl concentration in crops exhibits species-dependent preferences. The enrichment of Tl in edible crop species decreases in the following order： green cabbage〉chili〉Chinese cabbage〉rice〉com. The highest level of Tl in green cabbage is up to 500 mg/kg （DW）, surpassing the values of Tl in the soils （13-59 mg/kg）. The enrichment factor for TI in green cabbage is up to 1-10 when considering the HNO3-extracted Tl, but the factor highly rises to 30-1300 while considering the NH4Ac-extracted Tl. The average daily uptake of Tl by the local villagers through consumption of locally planted crops was estimated at about 1.9 mg per person, which is 50 times the daily ingestion from the Tl-free background area. 相似文献
15.
The present work demonstrates the environmental problems associated with the development and operation of a lined and unlined
landfill site, both used for municipal solid waste landfilling, that are situated next to the city of Patra, Greece. Findings
from a detailed site investigation as well calculations on hydrologic evaluation of landfill’s performance and measurements
on leachate composition proved that the lined landfill site is more secure and environmental friendly compared with the unlined
landfill site. Even though, until today, there is no evidence from near boreholes for severe contamination problems generated
by any of the two landfills, in the forthcoming future several environmental problems are expected to occur from the unlined
site. In addition the prevailing hydrogeotechnical conditions indicated that the unlined site is a potential source of contamination;
hence extra remedial measures should be received by the local authorities to prevent severe contamination in soil and groundwater. 相似文献
16.
A number of major problems associated with the containment approach to landfill management are highlighted. The fundamental flaw in the strategy is that dry entombment of waste inhibits its degradation, so prolonging the activity of the waste and delaying, possibly for several decades, its stabilisation to an inert state. This, coupled with uncertainties as to the long-term durability of synthetic lining systems, increases the potential, for liner failure at some stage in the future whilst the waste is still active, leading to groundwater pollution by landfill leachate. Clay liners also pose problems as the smectite components of bentonite liners are subject to chemical interaction with landfill leachate, leading to a reduction in their swelling capacity and increase in hydraulic conductivity. Thus, their ability to perform a containment role diminishes with time. More critically, if diffusion rather than advection is the dominant contaminant migration mechanism, then no liner will be completely impermeable to pollutants and the containment strategy becomes untenable. There are other less obvious problems with the containment strategy. One is the tendency to place total reliance on artificial lining systems and pay little attention to local geological/hydrogeological conditions during selection of landfill sites. Based on the attitude that any site can be engineered for landfilling and that complete protection of groundwater can be effected by lining systems, negative geological characteristics of sites are being ignored. Furthermore, excessive costs in construction and operation of containment landfills necessitate that they are large scale operations (superdumps), with associated transfer facilities and transport costs, all of which add to overall waste management costs. Taken together with unpredictable post-closure maintenance and monitoring costs, possibly over several decades, the economics of the containment strategy becomes unsustainable. Such a high-cost, high-technology approach to landfill leachate management is generally beyond the financial and technological resources of the less wealthy nations, and places severe burdens on their economies. For instance, in third world countries with limited water resources, the need to preserve groundwater quality is paramount, so expensive containment strategies are adopted in the belief that they offer greatest protection to groundwater. A final indictment of the containment strategy is that in delaying degradation of waste, the present generations waste problems will be left for future generations to deal with. More cost-effective landfill management strategies take advantage of the natural hydrogeological characteristics and attenuation properties of the subsurface. The ‘dilute and disperse’ strategy employs the natural sorption and ion exchange properties of clay minerals, and it has been shown that in appropriate situations it is effective in attenuating landfill leachate and preventing pollution of water resources. Operated at sites with thick clay overburden sequences, using a permeable cap to maximise rainfall infiltration and a leachate collection system to control leachate migration, ‘dilute and disperse’ is a viable leachate management strategy. Hydraulic traps are relatively common hydrogeological situations where groundwater flow is towards the landfill, so effectively suppressing outwards advective flow of leachate. This approach is also best employed with a clay liner, taking advantage of the attenuation properties of clays to combat diffusive flow of contaminants. These strategies are likely to guarantee greater protection of groundwater in the long term. 相似文献
17.
This paper presents a GIS-based multi-criteria site selection for municipal solid waste landfilling in Ariana Region, Tunisia. Based on the regional characteristics, literature related to disposal sites and waste management, local expert, data availability and assessments via questionnaires, 15 constraints, and 5 factors were built in the hierarchical structure for landfill suitability by multi-criteria evaluation. The factors are divided into environmental and socio-economic groups. The methodology is used for preliminary assessment of the 20-year most useful lifetime suitable landfilling sites by combining fuzzy set theory, weighted linear combination (WLC) and analytic hierarchy process (AHP) in a GIS environment. The criteria standardization is undertaken by application of different fuzzy membership functions. The fuzzy membership functions shape and their control points are chosen through assessment of expert opinion. The weightings of each selection criterion are assigned depending on the relative importance using the AHP methodology. The WLC approach is applied for alternative landfill sites prioritization. The results of this study showed five potential candidate sites, which are generated when the environmental factors are valued higher than socio-economic factors. These sites are ranked in descending order using the ELECTRE III method. However, the final decision will require further detailed geotechnical and hydrogeological analyses toward the protection of groundwater as well as surface water. 相似文献
18.
通过某危险废物安全填埋场项目,介绍了安全填埋工程的总体设计工艺,包括危险废物填埋处置总体流程、预处理系统、填埋库体结构、防渗系统、终场覆盖及环境监测等。结合工程设计实践,探讨了危险废物填埋场设计工艺要点。分析认为在沿海软土地区,采用双衬层水平防渗和垂直防渗相结合的半刚性结构方式,可以达到有效保护库区环境的目的。 相似文献
19.
Increase in waste generation calls for an effective waste management as this has become a necessity for environmental sustainability. Several methods are adopted in managing waste, which include waste reduction, reuse, thermal treatment, recycling and landfilling. The landfill method is recognised as the most used of all the waste management methods in developing countries such as Ghana. However, the selection of a suitable landfill site is very difficult and tedious. This is because it involves a consideration of many factors such as environmental, topographic, economic, socio-cultural and civil engineering. This research sought to identify a suitable landfill site by applying GIS multicriteria and weighted overlay approach in the Bongo District of Northern Ghana. The analysis relied on criteria and weights provided by the technocrats and the indigenes in the district as a way of demonstrating how landfill siting impasse can be resolved by incorporating the various stakeholders. The results obtained provided clear areas for landfill sites in the study area from the technocratic and the indigenous perspectives. However, the technocratic perspective failed to include an important cultural criterion, sacred groves, as a factor. The indigenous perspective also compromised on the factor related to nearness to residential areas, and is equally not sufficient on its own. The optimal landfill sites, which meets the expectations of both the technocrats and indigenes, was identified. This perspective has produced technically favourable and socio-culturally acceptable landfill site. However, it is recommended an environmental impact assessment (EIA) be conducted to identify the full environmental and social cost of the site. It is concluded that in landfill site selection much attention be given to cultural factors in the same way as the technical factors. 相似文献
20.
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。 相似文献
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