Hydrologic simulation of clay‐settling areas in the phosphate mining district,Florida     

Jing Zhang  Mark Ross 《水文研究》2012,26(24):3770-3778

Clay‐settling areas (CSAs) are one of the most conspicuous and development‐limiting landforms remaining after phosphate mining. Many questions are asked by the mining and regulatory communities with regard to the correct modelling (predictive) methods and assumptions that should be used to yield viable hydrologic post‐reclamation landforms within CSAs. Questions as to the correct methodology to use in modelling/predicting long‐term CSA hydrologic performance have historically been difficult to answer because the data and analysis to support popular hypotheses did not exist. The goal of this paper was to substantially improve the data, analysis and predictive methodology necessary to return CSAs to viable hydrologic units, and moreover, to develop better understanding of the hydrology of CSAs and their ability to support wetlands. The study site is located at the Fort Meade Mine in Polk County, Florida. In this paper, continuous model simulation and calibration of study site were conducted for the hydrologic model, Hydrological Simulation Program – FORTRAN, which was generally selected on the basis of its popularity in predicting the hydrologic behaviour of CSAs. The objective of this study was to simulate streamflow discharges and stage to estimate runoff response from these areas on the basis of the observed rainfall within the CSA. A set of global hydrologic parameters was selected and tested during the calibration by the parameter estimation software PEST. A comparison of the simulated and observed flow data indicates that the model calibration adequately reproduces the hydrologic response of the CSAs. The estimated parameters can be used as references for future application of the model. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Towards a comprehensive approach to parameter estimation in land surface parameterization schemes     

Rafael Rosolem  Hoshin V. Gupta  W. James Shuttleworth  Luis Gustavo Gonçalves de Gonçalves  Xubin Zeng 《水文研究》2013,27(14):2075-2097

In climate models, the land–atmosphere interactions are described numerically by land surface parameterization (LSP) schemes. The continuing improvement in realism in these schemes comes at the expense of the need to specify a large number of parameters that are either directly measured or estimated. Also, an emerging problem is whether the relationships used in LSPs are universal and globally applicable. One plausible approach to evaluate this is to first minimize uncertainty in model parameters by calibration. In this paper, we conduct a comprehensive analysis of some model diagnostics using a slightly modified version of the Simple Biosphere 3 model for a variety of biomes located mainly in the Amazon. First, the degree of influence of each individual parameter in simulating surface fluxes is identified. Next, we estimate parameters using a multi‐operator genetic algorithm applied in a multi‐objective context and evaluate simulations of energy and carbon fluxes against observations. Compared with the default parameter sets, these parameter estimates improve the partitioning of energy fluxes in forest and cropland sites and provide better simulations of daytime increases in assimilation of net carbon during the dry season at forest sites. Finally, a detailed assessment of the parameter estimation problem was performed by accounting for the decomposition of the mean squared error to the total model uncertainty. Analysis of the total prediction uncertainty reveals that the parameter adjustments significantly improve reproduction of the mean and variability of the flux time series at all sites and generally remove seasonality of the errors but do not improve dynamical properties. Our results demonstrate that error decomposition provides a meaningful and intuitive way to understand differences in model performance. To make further advancements in the knowledge of these models, we encourage the LSP community to adopt similar approaches in the future. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Sensitivity of soil parameters in unsaturated zone modelling and the relation between effective,laboratory and in situ estimates     

J. Mertens  H. Madsen  M. Kristensen  D. Jacques  J. Feyen 《水文研究》2005,19(8):1611-1633

Simulation of soil moisture content requires effective soil hydraulic parameters that are valid at the modelling scale. This study investigates how these parameters can be estimated by inverse modelling using soil moisture measurements at 25 locations at three different depths (at the surface, at 30 and 60 cm depth) on an 80 by 20 m hillslope. The study presents two global sensitivity analyses to investigate the sensitivity in simulated soil moisture content of the different hydraulic parameters used in a one‐dimensional unsaturated zone model based on Richards' equation. For estimation of the effective parameters the shuffled complex evolution algorithm is applied. These estimated parameters are compared to their measured laboratory and in situ equivalents. Soil hydraulic functions were estimated in the laboratory on 100 cm³ undisturbed soil cores collected at 115 locations situated in two horizons in three profile pits along the hillslope. Furthermore, in situ field saturated hydraulic conductivity was estimated at 120 locations using single‐ring pressure infiltrometer measurements. The sensitivity analysis of 13 soil physical parameters (saturated hydraulic conductivity (K_s), saturated moisture content (θ_s), residual moisture content (θ_r), inverse of the air‐entry value (α), van Genuchten shape parameter (n), Averjanov shape parameter (N) for both horizons, and depth (d) from surface to B horizon) in a two‐layer single column model showed that the parameter N is the least sensitive parameter. K_s of both horizons, θ_s of the A horizon and d were found to be the most sensitive parameters. Distributions over all locations of the effective parameters and the distributions of the estimated soil physical parameters from the undisturbed soil samples and the single‐ring pressure infiltrometer estimates were found significantly different at a 5% level for all parameters except for α of the A horizon and K_s and θ_s of the B horizon. Different reasons are discussed to explain these large differences. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Three‐parameter discontinuous distributions for hydrological samples with zero values     

Stanislaw Weglarczyk  Witold G. Strupczewski  Vijay P. Singh 《水文研究》2005,19(15):2899-2914

A consistent approach to the frequency analysis of hydrologic data in arid and semiarid regions, i.e. the data series containing several zero values (e.g. monthly precipitation in dry seasons, annual peak flow discharges, etc.), requires using discontinuous probability distribution functions. Such an approach has received relatively limited attention. Along the lines of physically based models, the extensions of the Muskingum‐based models to three parameter forms are considered. Using 44 peak flow series from the USGS data bank, the fitting ability of four three‐parameter models was investigated: (1) the Dirac delta combined with Gamma distribution; (2) the Dirac delta combined with two‐parameter generalized Pareto distribution; (3) the Dirac delta combined with two‐parameter Weibull (DWe) distribution; (4) the kinematic diffusion with one additional parameter that controls the probability of the zero event (KD3). The goodness of fit of the models was assessed and compared both by evaluation of discrepancies between the results of both estimation methods (i.e. the method of moments (MOM) and the maximum likelihood method (MLM)) and using the log of likelihood function as a criterion. In most cases, the DWe distribution with MLM‐estimated parameters showed the best fit of all the three‐parameter models. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Generalized plasticity state parameter‐based model for saturated and unsaturated soils. Part II: Unsaturated soil modeling     

Diego Manzanal  Manuel Pastor  José Antonio Fernández Merodo 《国际地质力学数值与分析法杂志》2011,35(18):1899-1917

The aim of this paper is to extend the generalized plasticity state parameter‐based model presented in part 1 to reproduce the hydro‐mechanical behavior of unsaturated soils. The proposed model is based on two pairs of stress–strain variables and a suitable hardening law taking into account the bonding—debonding effect of suction and degree of saturation. A generalized state parameter for unsaturated state is proposed to reproduce soil behavior using a single set of material parameters. Generalized plasticity gives a suitable framework to reproduce not only monotonic stress path but also cyclic behavior. The hydraulic hysteresis during a drying—wetting cycle and the void ratio effect on the hydraulic behavior is introduced. Comparison between model simulations and a series of experimental data available, both cohesive and granular, are given to illustrate the accuracy of the enhanced generalized plasticity equation. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

坐标系转换参数初值快速计算的新方法   总被引：2，自引：0，他引：2  

许文学  王保丰  羊远新  李锋 《测绘工程》2010,19(4):4-7

在已知不共线3点在两坐标系下坐标的条件下,提出一种快速计算两坐标系间转换参数概略值的方法。通过已知的3点构造出一个新的坐标系,根据该坐标系可计算出待求的两坐标系分别与它的旋转参数,从而求得待求两坐标系间的旋转参数。再根据旋转参数计算出平移参数的概略值。通过实验验证方法的正确性。  相似文献   

引入非线性瞬时弹性模量的软土流变模型     

谷任国  邹育  房营光  胡玉光 《岩土力学》2018,39(1):237-241

软土是一种非线性流变物质,但现行流变模型却忽略了加载瞬时的非线性变形;软土流变试验参数是数学模型参数而非物理模型参数,一个土样一般只对应一种材料参数,但现行流变模型的模型参数常随着荷载变化,且变化无规律,离散性大。基于以有机质为流变相物质的人工土试样室内一维压缩蠕变试验,建立了各级荷载作用下具有相同模型参数的7组件流变模型,用非线性弹簧H描述软土加载瞬时弹塑性变形、并联的三元件组件模拟软土随时间变化的黏弹塑变形。结果表明：引入三次非线性瞬时弹性模量的7组件流变模型能够较准确地反映软土的流变特性。  相似文献   

颗粒形状对碎石料孔隙特性影响研究     

叶加兵  张家发  邹维列 《岩土力学》2018,39(12):4457-4467

颗粒形状是影响碎石料孔隙特性的主要因素之一,进而影响碎石料的渗透特性和力学行为。选取粒径为2~5 mm和5~10 mm的灰岩碎石颗粒填筑试样,同时与相同级配和孔隙率的玻璃球试样进行对比研究,采用CT扫描技术和图形处理软件获取多孔介质孔隙边界轮廓,选取0.5 mm开度阈值分割孔隙;每组试样选取3张扫描断面图像,取定量参数的平均值为研究对象,对孔隙特性进行定量分析。结果表明：玻璃球多孔介质孔隙形状的复杂性甚于碎石料;玻璃球多孔介质孔隙系统的连通度大于同粒组碎石料。  相似文献   

饱和冻土中弹性体波传播特性影响参数研究     

仇浩淼  夏唐代  郑晴晴  周飞 《岩土力学》2018,39(11):4053-4062

基于Leclaire对饱和双相孔隙弹性介质Biot模型的扩展,研究含有两种不同固相组分的三相多孔弹性介质中体波的传播特性。以饱和冻土为例,分析了各相体积分数、颗粒形状,接触参数等因素对波动方程中惯性参数、黏性参数、刚度参数的影响;对该三相介质模型进行了退化,分析了孔隙中只含液态水或固态冰时体波的特性;以饱和冻土为例,通过数值计算,探讨了饱和冻土中体波的相速度和衰减系数与胶结参数、接触参数、频率、饱和度、孔隙率等参数的关系。结果表明：与一般的饱和土不同,饱和冻土中存在5种体波,即3种纵波和2种横波;5种体波均具有弥散性和衰减性,且P1波、S1波弥散性和衰减性远小于P2、P3、S2波;胶结参数、饱和度、孔隙率对5种体波的传播特性影响显著,接触参数对传播特性影响较小。  相似文献   

大直径超长灌注桩水平承载性能的参数敏感性     

李洪江  童立元  刘松玉  包红燕  杨涛 《岩土力学》2018,39(5):1825-1833

大直径超长灌注桩是高规格建（构）筑物桩基工程的发展趋势,但有关其水平承载性能的研究还较少。依托江苏靖江文化中心大直径超长灌注桩建设项目,通过现场试桩试验获得了桩身水平受力及承载变形特征。采用孔压静力触探（CPTU）测试p-y曲线法构建了大直径超长灌注桩水平承载数值计算模型,在与现场试桩结果比对验证之后,进一步研究了桩径尺寸效应、桩顶嵌固形式、桩身倾角、竖向载荷对大直径超长灌注桩的影响规律。最后通过计算各影响因素的参数敏感度,实现了对大直径超长灌注桩水平承载性能参数敏感性的客观定量评价。研究结果表明：原位测试CPTU可以很好地应用于大直径超长灌注桩的水平承载分析,大直径超长灌注桩参数敏感度由大到小依次为：桩顶嵌固形式、尺寸效应、竖向荷载、桩身倾角。  相似文献