共查询到18条相似文献，搜索用时 171 毫秒
1.
为了加速填埋场降解的稳定化,渗滤液回灌常被应用在工程实践中。使用竖井进行回灌是较为有效的方式之一。伴随着液体的注入,由于对流的产生,垃圾土温度势必会发生改变。基于无锡填埋场注水试验,对该现场试验过程中垃圾土温度的改变进行模拟。为此,建立了考虑渗透系数和孔隙率随深度变化的渗流模型,以及考虑渗流影响的热对流-热传导模型,并利用数值计算方法进行求解。在对比计算值和试验值之后,发现所建立的模型能较好地模拟注水期间渗滤液水位和垃圾土温度的变化规律。结果表明：在离注水井超过6 m处的位置,显现的液位相对滞后,至少滞后0.15 d,而且距离越远滞后的时间越长;在液位以下,注水井周围的垃圾土温度均低于初始温度。但是在径向上远离注水井3.6 m之外的垃圾土温度并不是全低于初始温度,在新老垃圾土交界处之上2 m范围内,会出现温度高于初始温度的现象,温度差可达3 ℃;新填垃圾土的已降解时长对单井注水工况下温度分布的影响较为显著。 相似文献
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文章针对填埋场沉降计算问题,对垃圾压缩机理进行了研究,建立了常应力作用下的垃圾压缩模型。该模型将城市生活垃圾的压缩分为主压缩和降解压缩,其中,主压缩与压力有关,降解压缩与压力和降解条件有关。降解条件包括有机质含量和降解速率;结合对填埋场分级堆填过程的分析,建立了考虑降解和分级堆填影响的填埋场一维沉降计算方法,并对计算参数的取值方法进行了研究。 相似文献
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基于城市固体废弃物(MSW)的降解及土力学特征,在应力降解模型、等向压缩特性和邓肯-张模型的理论基础上,建立了一个能够描述MSW应力和降解耦合作用的全量非线性本构模型。给出了不同应力状态下单元体体积和轴向变形随时间变化的数学表达,同时给出了所有参数的确定方法。采用该模型对不同龄期和不同围压条件下填埋场现场试样的三轴CD应力-应变曲线以及室内长期一维降解压缩试验进行了模拟。结果表明,模型概念合理、参数明确,能够较全面地描述不同降解龄期垃圾的本构关系,可用于分析填埋场的长期变形。 相似文献
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城市垃圾填埋场有机物降解沉降模型的研究 总被引：15，自引：4，他引：11
研究城市垃圾填埋场的有机物降解沉降是非常重要的,有机物的降解沉降是填埋场的主要沉降,并且降解沉降将持续很长一段时间,较大的沉降能够导致防渗系统的渗漏并损坏覆盖系统。由于垃圾的非均匀性,其土工特性随地域及时间而改变,所以,计算垃圾填埋场的降解沉降是比较困难的。在试验及理论推导的基础上,提出了一种有机物的降解沉降模型,该模型参数较少,利用该模型预测了天子岭垃圾填埋场的库容及有机物的降解沉降。 相似文献
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基于契比雪夫多项式的旅行时反演方法,不需进行入射角扫描,首先用多项式表示出深度和慢度,计算出从源点到接收点的旅行时间,通过与实际时间的误差修改模型参数,经过反复迭代,最终得到地下复杂构造的界面形态和速度变化。与网格化速度反演方法相比,计算的未知数少,对初始地质模型的依赖性小。模型试算表明,在初始地质模型与实际地质模型差别较大时,仍能取得比较好的反演结果。 相似文献
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通过对南岭西段花山和姑婆山花岗岩基地质-岩石地球化学特征研究,判明它们的侵位深度(5.5km)、围岩温度(196℃)及岩浆初始温度(950℃),建立起花山和姑婆山岩基的数学计算模型,计算得出:花山-姑婆山花岗岩熔体侵位后,其初始温度降低至结晶温度所需的时间(△tco1)分别为4.14 Ma(花山)和4.36Ma(姑婆山);由于结晶潜热释放而使结晶过程延长的时间(△tL)为2.67Ma,2.81 Ma;由于花山和姑婆山花岗岩基放射性元素含量(U 13.5×10-6,Th 56.1×10- 6,K2O 5.79％(花山);U13.7×10-6,Th 52.4×10-6,K2O 5.28％(姑婆山))高于世界平均花岗岩放射性元素含量(U5×10-6,Th 20×10-6,K2O 2.66％),花山和姑婆山花岗岩浆侵位后产生的放射成因热使结晶过程延长的时间(△tA)分别为37.6 Ma和45.1 Ma,远长于按世界平均花岗岩放射性元素含量计算得出的△tA(3.17 Ma,花山).花山和姑婆山花岗岩基的侵位-结晶时差(△tECTD)分别为44.41Ma和52.27Ma,结合锆石U-Pb年龄值(162 Ma(花山),163Ma(姑婆山)),通过反演计算得出花山、姑婆山花岗岩基侵位年龄值(tE)分别为206Ma和215Ma,从而为花山-姑婆山花岗岩基属于印支期侵位提供了重要的岩浆动力学佐证. 相似文献
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高堆石坝瞬变-流变参数三维全过程联合反演方法及变形预测 总被引：1，自引：0，他引：1
利用反演分析得到的参数进行高面板坝的应力、变形分析来预测长期变形。由于堆石坝的施工过程和变形机制比较复杂,很难将瞬时变形和流变变形分开,因此,有必要对静力本构模型参数和流变模型参数进行综合反演。利用实测位移资料,以对堆石坝变形较敏感的静力本构模型和流变模型参数为待反演参数,采用基于粒子迁徙的粒子群算法和径向基函数神经网络构建参数反演平台,该方法克服了粒子群算法易陷入局部最优和早熟收敛的缺点,采用经过训练的神经网络来描述模型参数和位移之间的映射关系,节省了参数反演的计算时间。对水布垭高面板坝的反演结果表明,基于反演参数的沉降计算值与实测值吻合得很好,坝体变形在合理范围以内并趋于稳定。 相似文献
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土体本构参数的合理取值是数值模拟的重要前提。为准确获取湖州软土修正剑桥模型参数,针对该地区两种典型软土,提出了基于室内试验-神经网络的软土修正剑桥模型参数反演方法。首先,开展了室内三轴固结不排水试验及标准固结-回弹试验,基于室内试验结果确定了湖州地区典型软土修正剑桥模型参数反演区间;其次,基于正交试验设计原理,对基坑开挖过程中不同参数水平下维护结构侧移进行数值计算,根据数值计算结果构造出64组PSO-BP神经网络训练样本;最后,利用构造的训练集对湖州地区软土修正剑桥模型参数进行反演。研究结果表明：反演得到的两种典型软土修正剑桥模型参数临界状态有效应力比M1、M2,压缩参数λ1、λ2,回弹参数κ1、κ2及孔隙比e1、e2分别为M1=1.076、λ1=0.050、κ1=0.021、e1=1.712,M2=1.... 相似文献
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《岩土力学》2021,(Z1)
核废料处置库的温度场演化规律是处置库设计和安全评估的重要依据, 根据处置库的概念化设计,建立了单个核废料废物罐的分层热传导模型。对膨润土区和围岩区热传导方程组进行Laplace变换,联立求解得到了在不同内外边界条件组合情况下变换域内的温度场半解析解。采用Crump方法对半解析解进行数值反演,获得废物罐近场时间-空间域的温度分布,最后分析了不同参数条件下单个废物罐表面温度的变化规律。结果表明,核废料的燃烧值越高,冷却时间越短,废物罐表面温度越高;采用有限外边界条件计算得到的废物罐表面温度要高于无限外边界条件;膨润土的导热系数越大,废物罐表面温度越低,膨润土土层厚度越厚,越不利于内部温度的扩散。研究成果可用于评价不同条件下废物罐近场温度的演化规律。 相似文献
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This paper shows the potential of gravity data to map a buried landfill bottom topography. To this end, a gravity inversion
method is presented for estimating the landfill’s bottom depths at discrete points assuming a decrease of the density contrast
with depth according to a hyperbolic law. The method’s efficiency was tested using synthetic data from simulated waste landfills,
producing estimated bottom topographies very close to the true ones. The method’s potentiality has been further evaluated
in applying it to the gravity data from the abandoned Thomas Farm Landfill site, Indiana, USA, whose bottom topography is
known. The estimated topography showed close agreement with the known Thomas Farm Landfill’s bottom topography. 相似文献
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地热异常区的探测对于地热能开发利用至关重要。利用2 m测温法和相关仪器对厦门东山某热泉地区进行实地探测,获取1~2m深度地层温度和导热系数数据,绘制研究区2m深度温度等值线图和浅层热流密度分布云图,圈定地热异常区。运用一维稳态热传导模型对研究区20 m深度地温进行反演,并与研究区20m深度实测温度进行对比分析。结果表明,2m测温法对地热异常区探测效果明显,一维稳态热传导模型对于20m深度地温的预测结果与实测结果较为一致。该方法可以作为地热探测初期的有效手段。 相似文献
13.
Vladimir Frid Dmitri Doudkinski Gady Liskevich Efim Shafran Arie Averbakh Nikolay Korostishevsky Larisa Prihodko 《Environmental Earth Sciences》2010,60(4):787-798
This paper deals with the integration of electrical resistivity tomography and geochemical methods for studying four different
fire-prone landfills. Landfill gas composition (CH4, H2S, O2, CO, CO2) and subsurface temperature were measured with the constant net 50 × 50 m from the depth 10–60 cm. 28 electrical resistivity
tomography lines were surveyed, while Wenner and Sclumberger electrode arrays were employed for all measurements. At the studied
sites the landfill gas and temperature measurements mapped gas and temperature anomalies over underground fire sources. 2D
electrical resistivity tomography lines, performed over these anomalies, showed these fire sources as high-resistivity zones.
The joint employment of the electrical imaging and geochemical survey seems to be a useful tool in carrying out diagnostic
investigations at fire-prone landfills. 相似文献
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In this paper the effect of transient uplift/erosion on the relationship between surface heat flow and heat generation for
truncated exponential model of radiogenic heat source distribution and basal asthenospheric convection is investigated. Asthenospheric
convection is described by a parameterized model, in the form of a nonlinear heat flux boundary condition involving basal
temperature and mantle internal temperature. This boundary condition has been linearized and the analytical solution of the
problem is obtained by the eigenvalue-eigenfunction expansion method. The analytical solution is used to derive the nature
of surface heat flow and heat generation relationship. The results show that the linear relationship is maintained during
the uplift/erosion and the estimates of the slope of the linear relationship are different from the depth scale of the exponential
model and increase with the rate of uplift/erosion. The estimates of the reduced heat flow also increase with the rate of
uplift/erosion. These results would find applications in the interpretation of linear surface heat flow and heat generation
relationship which is observed in different tectonic environment. 相似文献
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Bioreactor landfills are operated for rapid stabilization of waste, increased landfill gas generation for cost-effective energy
recovery, gain in landfill space, enhanced leachate treatment, and reduced post closure maintenance period. The fundamental
process of waste stabilization in bioreactor landfill is recirculation of generated leachate back into the landfills. This
creates a favorable environment for rapid microbial decomposition of the biodegradable solid waste. In order to better estimate
the generated leachate and design of leachate recirculation system, clear understanding of the permeability of the Municipal
Solid Waste (MSW) with degradation and the factors influencing the permeability is necessary. The objective of the paper is
to determine the changes in hydraulic properties of MSW in bioreactor landfill with time and decomposition. Four small-scale
bioreactor landfills were built in laboratory and samples were prepared to represent each phase of decomposition. Then, the
changes in hydraulic properties of MSW in bioreactor landfill with time and decomposition were determined. A series of constant
head permeability tests were performed on the samples generated in laboratory scale bioreactor landfills to determine variation
of permeability of MSW with degradation. The test results indicated that the permeability of MSW in bioreactor landfills decreases
with decomposition. Based on the test results, the permeability of MSW at the first phase of degradation was estimated as
0.0088 cm/s at density 700 kg/m3. However, with degradation, permeability decreased to 0.0013 cm/s at the same density, for MSW at Phase IV. 相似文献
18.
Responses of municipal solid waste (MSW) landfills during earthquakes are gaining worldwide importance due to the devastating nature of earthquake on landfills. Apart from the post-earthquake safety and serviceability issues which pose environmental and public health problems, other important concerns are related to the behavior of closed landfills during and after earthquake. In present study, one dimensional (1-D) equivalent-linear analysis was carried out to model the behaviour of MSW landfills subjected to seismic base accelerations using the DEEPSOIL software. Influence of foundation types, height and stiffness of MSW landfills and seismic base accelerations on the seismic responses in terms of surface accelerations, normalized stresses (i.e., shear stress/effective vertical stress) and spectral amplification are evaluated. The results showed that height and stiffness of landfills, type of foundation and amount of seismic base acceleration and period play important role in evaluating the seismic responses of MSW landfills. Assumption of constant unit weight and shear wave velocity for landfills underestimates maximum horizontal acceleration (MHA), normalized shear stresses and spectral amplification at the top of landfills. Landfill models with smaller heights (up to 40 m high) showed higher amplification ratio for low seismic base accelerations with mean period near to that of soil and landfill resonance for all sites. A complex behavior was observed at higher seismic base accelerations due to non-linear behavior of landfill materials. 相似文献