Geotechnical behavior of the MSW in Tianziling landfill

INTRODUCTIONTheTianzilingwastelandfillbuiltin 1991toproperlydisposeofmunicipalsolidwaste(MSW)hasadesignedservicelifeof13years.Itwasfilledstagebystageatthebeginningoftheelevationof 50 .5m .Bynow ,thelandfillhasreachedthelevelof 10 2 .5m ,whichex ceedst…     

Geotechnical behavior of the MSW in Tianziling landfill

The valley shaped Tianziling landfill of Hangzhou in China built in 1991 to dispose of municipal solid waste (MSW) was designed for a service life of 13 years. The problem of waste landfill slope stability and expansion must be considered from the geotechnical engineering point of view, for which purpose, it is necessary to understand the geotechnical properties of the MSW in the landfill, some of whose-physical properties were measured by common geotechnical tests, such as those on unit weight, water content, organic matter content, specific gravity, coefficient of permeability, compressibility, etc. The mechanical properties were studied by direct shear test, triaxial compression test, and static and dynamic penetration tests. Some strength parameters for engineering analysis were obtained. Project supported by National Natural Science Foundation of China (No. 59508012)     

Study on determination of the stable slope configuration for deep open pit mine

The space effects of deep pit slope are analyzed by an elastic mechanics principle. The interaction among the critical slide angle, the friction coefficient, the cohesion, and the horizontal radius of the deep pits is derived in this paper. It indicates that the deeper the pit is excavated, the greater the critical slide angle is. Both the theory for reducing stripping waste rock in deep pit and the approach to determining the configuration of the stable slope are developed from the interaction. The theory in this paper comprises the preceding principles of stability analysis of slopes and is suitable for analyzing that of deep pit.     

松散岩体在采空区内应力状态的数值模拟研究

针对采空区内的松散岩体,运用三维有限差分法建立了数值模型对其进行分析;研究结果表明,在不同埋深条件下松散岩体的应力呈直线变化;对于水平应力,其斜率间的关系近似成指数关系;对于垂直应力,随埋深增大斜率没有变化;在不同冒落高度条件下,松散岩体的水平应力变化成多项式,次数随冒落高度依次升高;垂直应力变化曲线随冒落高度由直线逐渐变成对数曲线;在压实松散岩体过程中,应力在初始循环时步变化大;不同冒落高度条件下,循环时步随高度增大。     

斜坡稳定分析的解析法

假定斜坡的滑移面为直线,用极限平衡法推导了倾斜边坡的临界高度和临界坡角,解出了倾斜边坡中安全系数最小的滑动面的位置,确定了边坡中稳定土体的临界角度.结果用解析式表达,为边坡的稳定分析和设计提供了可靠的理论依据.     

Experimental research on the compressibility of stale waste

1. Introduction In October 2000, the Chongqing government received an exciting message. The Planning Committee of China approved the feasibility reports on Changshengqiao sanitary landfill projects supported by a loan from World Bank. This indicates that the Chinese government and local governments of different ranks have come to realize the importance of city environment and sanitation, and it also stands for the termination of simple and easy landfills. Before 2015, two modern sanitary l…     

井工采区不同开采时序对边坡滑移破坏机制的影响

以紫金山金铜矿开采为工程背景,根据矿山规划设计,露采至+100 m水平后进行井工开采。为了研究井工开采对露天边坡的影响,采用FLAC3D建立数值模型,研究采区位于边坡体不同空间位置对边坡稳定性产生的不同作用机制,分析露天边坡和采空区围岩位移演化规律、应力分布规律。数值模拟结果表明:当井采区位于边坡坡脚区时,井工开采直接破坏了坡脚区边坡岩体,坡面整体向坡脚处滑移,最大水平位移达到2.21 m,最大竖向位移达到1.67 m;当井采区位于坡中区开采时,其开采破坏了坡中边坡岩体,可能导致上部坡体失稳破坏;当井采区位于坡外区时,由于采区上部岩层沉陷导致边坡整体坡角减小,从而有利于边坡整体稳定性。对比3种开采位置,采区位于坡脚时对边坡稳定性最不利,采区处于坡外时采动效应对边坡稳定性的影响最低。     

Analysis of the dynamic stress path under obliquely incident P-waves and its influencing factors

The dynamic stress path of a rock and soil mass under seismic action has a crucial influence on its catastrophic behavior. In soil dynamics, earthquakes are commonly simplified as vertically incident shear waves and the seismic stresses in soil are estimated based on rigid foundation models. However, the great effect of P-waves should not be overlooked in strong earthquakes, which have happened frequently in recent years. The characteristics of the dynamic stress path under longitudinal waves with significant oblique incidence are still unclear. Analytical formulas for the seismic stresses at any depth of a semi-infinite elastic space under obliquely incident P-waves are derived, which degenerate into the traditional rigid foundation method in soil dynamics when both the incident angle and Poisson’s ratio are taken as zero. Here, we reveal the fundamental characteristics of a dynamic stress path under obliquely incident P-waves. The stress path is proved mathematically to be an oblique ellipse in the plane of normal stress difference and horizontal shear stress. We identify factors affecting the stress path, including the incident angle, Poisson’s ratio, and depth corresponding to unit wavelength. The possible variation in the range of an oblique elliptic stress path is systematically analyzed, which lays a theoretical foundation for further study of the dynamic response of sites under obliquely incident seismic waves.     

词汇衔接理论在大学英语阅读教学中的应用

英语语篇的词汇衔接手段分为两大类:复现关系和同现关系。本文根据词汇衔接理论的主要内容,阐述了词汇衔接在英语阅读教学中的具体应用。     

浅析黄土边坡降雨入渗及稳定性研究方法

降雨入渗是非饱和黄土边坡失稳的主要诱发因素,滑坡与降雨有着密切的关系。黄土边坡稳定性问题越来越引起岩土工程界的重视,降雨对边坡的稳定性影响的研究还不尽完善。本文浅析了非饱和黄土边坡雨水入渗及稳定性研究的现状,均为某一实例边坡,尚缺乏对边坡问题的系统研究。基于此,本文在前人的基础上研究了坡高、坡度、干密度、含水量等因素影响下黄土边坡内水分场的分布规律,而且进一步对不同因素影响下的黄土边坡的安全系数进行了计算分析。     

论Geo—slope中背水面边界条件选取问题

对西安市某均质土坝,库水位在最高水位的工况下,用有限元分析软件Geo—slope计算分析了背水面不同高度的透水边界对渗流场和背水面边坡安全系数的计算结果的影响。结果发现,背水面透水边界在合理的高度以下上升时总流量、出溢流量、出溢口处水力坡降、背水面边坡安全系数增大;背水面透水边界在合理的高度以上升高时这四个代表值减小。说明了合理的背水面透水边界为各个流场代表值和边坡安全系数的极值点。     

Wave Height Distribution for Spilling Waves in and outside the Surf Zone

Wave breaking plays an important role in sedi- ment transport and beach profile change. Breaking waves exhibit various patterns, principally depending on the incident wave steepness and the beach slope. The breaking patterns range from the relatively con- trolled spilling type to the violent and sudden plunging breaker type. The breaker patterns are classified into 3 or 4 categories. Some criteria for breaker pat- terns[1] are given in Tab. 1. Several wave decay models have been proposed to d…     

水压力条件下的含裂隙边坡动力响应数值分析

在考虑坝水耦合振动影响下,对拱坝边坡在地震作用下承受的动水压力进行了理论分析和数值计算。对正常蓄水位时、枯水位时边坡地震响应进行了分析。包括边坡的损伤演化、应力、位移的分析。在水坝地震动力分析中,应当将边坡、库水和地基三者作为一个综合的振动系统进行动力分析,考虑它们之间的相互作用,为类似库区边坡稳定性评价和边坡加固提供理论依据。     

Assessment of highway slope failure using neural networks

An artificial intelligence technique of back-propagation neural networks is used to assess the slope failure. On-site slope failure data from the South Cross-Island Highway in southern Taiwan are used to test the performance of the neural network model. The numerical results demonstrate the effectiveness of artificial neural networks in the evaluation of slope failure potential based on five major factors, such as the slope gradient angle, the slope height, the cumulative precipitation, daily rainfall and strength of materials.     

屋面雨水利用系统量化评估中径流系数的取值(英文)

为了实现屋面雨水利用系统量化评估中径流系数的精确取值,通过连续3年(2010—2012年)对河北省邯郸市不同屋面类型(屋面坡度和材料)及降雨特征(降雨深度和强度)的屋面径流进行实地监测,得到了各场实际降雨屋面径流系数的不同取值.研究结果表明,屋面径流系数的取值分布与各降雨事件的降雨深度相关性较强,其他影响因素对其影响较小.场次径流系数的取值与降雨深度呈显著的分段线性关系.根据1960—2008年的日降雨数据资料,计算得出邯郸市年均屋面径流系数可近似按照0.62这一常数进行取值.该研究成果可用于屋面雨水利用系统的量化评估及运行分析.     

洛阳市盘龙冢垃圾填埋场渗滤液污染与处理现状的调查

填埋已成为我国城市生活垃圾的一种主要处理方式。对填埋过程中产生的垃圾渗滤液进行分析评价并进行处理,已成为防止其造成二次污染的一个必要环节。基于对洛阳市盘龙冢垃圾填埋场渗滤液处理处置的必要性和紧迫性的分析,采用单项污染指数法对其水质进行分析评价,对其污染现状进行分析和讨论,并对其处理现状进行了深入调查。     

哈尔滨市柳树林垃圾场垃圾渗滤液对周边土壤污染状况的调查

在由于城市的发展人口的增加,垃圾产生量逐渐增多,产生的垃圾渗滤液对垃圾场底部及其周围的土壤、地下水造成了严重的污染。通过对污染土壤样品的调查分析,结果表明：在水平方向,垃圾堆放场周围200m范围土壤被严重污染；在垃圾场底部垂直方向,随着深度的增加垃圾渗滤液的含量逐渐的减少,在6m处含量收敛于背景值。     

One-dimensional coupled model for landfill gas and water transport in layered unsaturated soil cover systems

Cover systems are used to prevent water infiltration into a waste body. They also play an important role in controlling landfill gas transport from the waste body to the atmosphere. It is important to assess the flux of landfill gas at the surface of a cover system by considering the coupled effects of rainwater infiltration and gas transport in the cover soils. We have developed a 1D mathematical model for coupled transient gas and water transport in unsaturated cover soils. The coupled model was solved by the finite element method. Results obtained by the proposed model agreed well with experimental data. Based on the proposed solution, the influences of gas pressure, gas permeability, and the thickness of the cover soils on soil gas concentration profiles were investigated. The difference in soil gas concentration reached up to 31% as the thickness of cover increased from 1 to 2 m. Gas concentration at a depth of 0.2 m decreased by 6% as the amplitude of atmospheric gas pressure fluctuation increased from 20 to 100 Pa. The gas concentration increased by only 3% when gas permeability increased by a factor of 2 for a relatively long period of gas migration (e.g., 60 h) under the given conditions. Results suggest that both diffusion and advection should be considered when estimating gas transport in unsaturated cover soils. The numerical model can be used in the design of cover systems in relation to gas breakthrough time, breakthrough concentration, and flux.     

Numerical Analysis of the Stability of Embankment Slope Reinforced with Piles

The effects of stabilizing piles on the stability of an embankment slope are analyzed by numerical simulation. The shear strength reduction method is used for the analysis, and the soil - pile interaction is simulated with zero-thickness elasto-plastic interface elements. Effects of pile spacing and pile position on the safety factor of slope and the behavior of piles under these conditions are given. The numerical analysis indicates that the positions of the pile have significant influence on the stability of the slope, and the pile needs to be installed in the middle of the slope for maximum safety factors. In the end, the soil arching effect closely associated with the space between stabilizing piles is analyzed. The results are helpful for design and construction of stabilizing piles.     

梅州市龙丰垃圾填埋场封场后适种性研究

通过对梅州市龙丰垃圾填埋场的地理环境、运营模式、土壤性质和营养土层的研究,发现该填埋场具有中等的植被生长条件,废气影响小,覆盖土层达1m以上,无渗滤液的危害.有必要施加以N、P、K为主的复合肥或有机肥,以增加土壤的肥力,有利于植物的快速生长.研究结果表明,龙丰垃圾填埋场可进行植被修复,并可为相关研究提供科学依据.