52、废弃物掩埋场边坡稳定分析

摘　要：台湾地区因可用空间有限，废弃物掩埋处理问题正面临极大困境。目前国内之废弃物掩埋场，大多利用城镇周边之山坡或山谷地形构筑。常常在颇为陡峭的坡面上设置阻水系统，而掩埋完成后的最终表面的坡度也往往非常大。掩埋场边坡滑动发生时，通常造成阻水系统之破坏，使未经处理之渗出水排出掩埋场，导致整体功能无法有效发挥。在掩埋场设计过程中，对大地工程师而言，最重要的工作之一为边坡稳定分析。现阶段掩埋场之边坡虽多采有限力平衡分析(Limit Equilibrium Analysis)，但国内外并无规范限制采用特定之分析程序。若就目前国外经常采用之几种分析方式予以比较，发现其分析结果出入甚大，在某些状况下，边坡稳定安全系数相差 50% 以上。若采用上述方法设计加劲之边坡，则求出所需之加劲材的抗张强度，差距更为可观。本文利用有限元素法分析之结果提出改良之掩埋场边坡分析与设计方法。依据研究结果，对边坡滑动之安全系数推算与加劲材需求计算应以不同方式处理，可分别对防止无加劲边坡滑动，与有效使用加劲材稳定边坡做出最佳设计。

53、废弃物掩埋场防止地下水污染之有效性评估
摘 要:设置废弃物掩埋场之目的在于隔绝废弃物与周遭环境，其中最重要的一项考虑是保护地下水源不受掩埋场中废弃物产生之渗出水污染。根据我国现行环境保护法规中之事业废弃物贮存清除处理方法及设施标准与一般废弃物卫生掩埋场设置规范，有害事业废弃物掩埋场须设置由不透水布与 60 公分厚黏土组成之复合阻水层(Composite Liner)，而一般事业废弃物掩埋场则仅须设置由黏土或不透水布构成的单一阻水层。本文就废弃物之特性与掩埋场阻水设施设置规范，利用作者研究国外掩埋场阻水层渗漏率(Leakage Rate)之经验，并参考国外专家对阻水层渗透率之分析结果，对一般与有害废弃物造成地下水污染之可能性作一分析。分析结果显示，依目前我国之设置规范与施工质量，大量之渗出水将会由仅使用单一阻水层之掩埋场渗漏。除非使用复合阻水层，否则掩埋场并不如预期般有效防止地下水污染。

54、废弃物掩埋场覆盖系统变形分析
摘 要: 废弃物掩埋场为防止渗出水污染地下水，除了在底部有阻水系统外，最上层应设置覆盖系统。覆盖系统不仅将废弃物与地表环境隔绝，并可减少雨水入渗以减低渗出水量。此外，也提供收集废气、植生美化等其它功能。由于可能利用封闭之掩埋场区域做为民众之休憩场所，或其它有限用途的利用，故基于安全与维护上之考虑，必须估算最终覆盖之变形量，以利做恰当之设计。本研究利用有限元素数值方法，推估最终覆盖之长期变形量。结果发现依据目前常用设计规范所建构的加劲或未加劲之稳定边坡可能产生一公尺以上之下坡变位。此外，并依据对不同状况之计算结果，指出工程师如何可以用适当之设计减少覆盖系统可能发生之长期变形。

关键词：掩埋场、覆盖系统、地工合成材、边坡稳定、有限元素法、变形

55、封场破坏教训

ABSTRACT:A sliding failure which occurred during construction of a composite landfill cover is evaluated. Field and laboratory testing showed that gas pore pressures were a significant cause of the failure. The paper shows the sensitivity of slope stability to relatively small changes in gas pore pressure and strength properties of the cover materials. Recommendations are included to help avoid this type of failure.
KEYWORDS:Landfill, Final cover, Composite barrier, Failure, Field observations.

56、封场覆盖土的分析和设计

摘 要: The sliding of cover soils on slopes underlain by geosynthetics is obviously an unacceptable situation and, if the number of occurrences becomes excessive, will eventually reflect poorly on the entire technology. Steeply sloped Ieachate collection layers and final covers of landfills are situations where incidents of such sliding have occurred.
Paradoxically, the analytic formulation of the situation is quite straightforward. This paper presents an analysis of the common problem of a veneer of cover soil (0.3 to 1.0 m thick) on a geosynthetic material at a given slope angle and length so as to arrive at a FS-value. The paper then presents different scenarios that create lower FS-values than the gravitational stresses of the above situation, e.g., equipment loads, seepage forces and seismic loads. As a counterpoint, different scenari,m that create higher FS-values also are presented, e.g., toe berms, tapered thickness cover soils and veneer reinforcement. In this latter category, a subdivision is made between intentional reinforcement (using geo.grids or high strength geotextiles) and nonintentional reinforcement (cases where geosynthetics overlay a weak interface within a multilayered slope). Hypothetical numeric examples are used in each of the above situations to illustrate the various influences on the resulting FS-value. In many cases, design curves are also generated. Suggested minimum FS-values Are presented for final closures of landfills, waste piles, leach pads, etc., which are the situations where veneer slides of this type are the most troublesome. Hopefully, the paper will serve as a vehicle to bring a greater awareness to such situations so as to avert slides from occurring in the future.

关键词：Analysis, Design, Limit Equilibrium Methods, Steep Slopes, Veneer Stability.

57、封场气体压力减少提高边坡稳定设计

ABSTRACT: Pore pressures generated by landfill gas underneath a geomembrane final cover can significantly reduce the effective normal stress on the lower geomembrane interface to the point of creating a cover veneer instability. An estimation of gas flux from the landfill surface can allow a gas-relief layer to be designed using Darcy’s law for gas flow through a porous medium. The methodology incorporates knowledge of the gas transmissivity of a chosen medium to design a spacing for highly-permeable strip drains. The strip drains in turn would discharge the gas either to vents or an active gas collection system. The gas-relief layer typically consists of sand or a geonet-composite. Limited testing of nonwoven-needlepunched (NWNP) geotextiles indicates that these materials may also be acceptable for gas relief in some designs. However, more testing is recommended before using NWNP geotextiles alone in this application. A failure case histories is presented that supports the design theory recommended in the paper. The greatest assumption in the proposed methodology concerns the estimation of gas flux. More work is needed in this regard.

58、高导排土工复合排水材料用于渗滤液收集系统

This technical note shows that leachate collection systems can be constructed parallel strips of high-transmissivity geocomposite associated with a layer of sand. It will be seen that, if this type of leachate collection system is properly designed, it meets the same performance and regulatory requirements as usual leachate collection system entirely constructed with a layer of geocomposite. A leachate collection system is typically constructed on a slope defined by its angle, β, and its length, L, measured horizontally from the crest to the toe of the slope (Figure 1). In this technical note, the area covered by the leachate collection system is referred to as “the slope”, even in the case of the very gentle slope (e.g. 2%) at the base of a landfill. The hydraulic gradient for flow along the slope is sin β.

59、灰渣污泥混合填埋

ABSTRACT: The geotechnical properties of a mixture of municipal solid waste incinerator bottom ash and municipal wastewater treatment plant sludge was investigated for a proposed ash/sludge secure landfill. The components as well as mixtures ranging from 10:1 to 5:1 (ash:sludge, by volume) were evaluated, where appropriate, for a number of geotechnical index and mechanical properties including particle size, water content, specific gravity, density-moisture relationships, shear strength, and compressibility. The results from a compactibility study and stability analysis of the proposed landfill were used to help approve a landfill codisposal concept; a full-scale facility was constructed and is currently operating successfully.

60、垃圾填埋场的缺陷技术

This report presents a review of the information available pertinent to public health and environmental quality protection issues for proposed Subtitle D landfills. Based on this review it is concluded that this type of landfill will at most locations cause groundwater pollution by landfill leachate and be adverse to the health, welfare and interests of nearby residents and property owners. As discussed, there is normally significant justification for those near a proposed Subtitle D landfill to oppose the development of the landfill.

61、垃圾填埋场设计运营封场手册

The United States is facing a major municipal solid waste management challenge. In 1990, a total of 195.7 million tons of municipal solid waste (MSW) was generated in our country (U.S. EPA, 1992a), approximately 88 percent of which was disposed in landfills (see Figure l-l). Three factors illustrate the MSW management problems that must be addressed, especially as they relate to landfills: