扎赉诺尔煤田水文地球化学特征及成因分析     

武文  莫若平  孙培城  刘文国 《内蒙古地质》2002,(4)

扎赉诺尔煤田地处山前,有利的地理环境条件形成了独特的水文地质特征—地下水的垂直分带和地下水顺层径流。其特有的水文地球化学环境导致了地下水成分的差异性。本文从水文地球化学的角度,对煤田地下水的水文地球化学特征及成因进行了论述分析。  相似文献   

考虑入渗和蒸发影响的土坡稳定性分析方法   总被引：47，自引：7，他引：47  

陈守义 《岩土力学》1997,18(2):8-12,22

本研究建议的一种分析方法假定斜坡非饱和土体的水分运动参数及剪强度参数与饱和度的依赖关系均可根据实验或经验确定。通过数值计算方法妥任意给定的入渗和蒸发边界条件下斜坡土体的瞬态含水率分布及与其相对应的瞬态抗剪强度参数分布。在此基础上瞬态斜坡安全因数即可通过常规的稳定性分析方法求得。  相似文献   

非饱和土壤Richards方程入渗求解探讨   总被引：3，自引：0，他引：3  

王玉珉  王印杰 《水文地质工程地质》2004,31(1):9-13,18

根据理查兹 (Richards)方程求解非饱和土壤垂直一维入渗率历时规律 ,因缺乏土壤水分特性函数K(θ)、D(θ)的一般有效公式 ,而采用与实际相差甚远的定值或线性函数假设 ,使成果隐含过多经验成分或需要反复迭代计算。笔者在文献 [1]中提出的非饱和土壤水分特性函数的一般有效基础公式 ,用分离变量法直接求解Richards方程 ,用土壤水动力学方法分别导出了含有渗前土湿因子的新入渗公式。它摆脱了同类入渗公式对水分函数过于简单的概化假设和经验成分。为放弃迄今水文学产流计算中惯用的下渗容量曲线“截首留尾”的经验做法 ,以直接使用含有渗前土湿因子的下渗公式提供了理论依据 ,从而将有利于产流计算方法的改进和计算精度的提高。  相似文献   

Contrasting hydrological response of coastal and desert biocrusts          下载免费PDF全文

Giora J. Kidron  Burkhard Büdel 《水文研究》2014,28(2):361-371

Biocrusts abound in southern Israel, covering the Hallamish dune field near Nizzana (NIZ) in the Negev (mean annual precipitation of 95 mm) and the coast of Nizzanim (NIM) near Ashdod (mean annual precipitation of 500 mm). While the hydrological response of the NIZ crust to natural rain events was thoroughly investigated, no data is available on the hydrological response of the NIM crust. Runoff was monitored in runoff plots during the years 2005–2008, and in addition, sprinkling experiments were carried out on NIM and NIZ crusts. For the evaluation of the possible factors that may control runoff initiation, fine content of the parent material, crust thickness, compressional strength, hydrophobicity, surface microrelief, organic matter, biomass (chlorophyll a and total carbohydrates) and the crust's species composition of NIM were studied and compared to that of NIZ. The data showed that in comparison to the NIZ crust that readily generated runoff, no runoff was produced by the NIM crust. This was so despite the fact that (1) Microculeus vaginatus predominated in both crusts, (2) the substantially higher rain intensities in NIM, (3) the greater thickness and higher chlorophyll content and (4) the lower microrelief at NIM in comparison to NIZ. The lack of runoff in NIM was explained by its low amounts of exopolysaccharides that did not suffice to affectively clog the surface and in turn to facilitate runoff initiation. The absence of runoff and its consequences on the NIM ecosystem are discussed. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Development of a soil moisture‐based distributed hydrologic model for determining hydrologically based critical source areas          下载免费PDF全文

Sisi Li  Margaret Gitau  David Bosch  Bernard A. Engel  Liang Zhang  Yun Du 《水文研究》2017,31(20):3543-3557

A simple grid cell‐based distributed hydrologic model was developed to provide spatial information on hydrologic components for determining hydrologically based critical source areas. The model represents the critical process (soil moisture variation) to run‐off generation accounting for both local and global water balance. In this way, it simulates both infiltration excess run‐off and saturation excess run‐off. The model was tested by multisite and multivariable evaluation on the 50‐km² Little River Experimental Watershed I in Georgia, U.S. and 2 smaller nested subwatersheds. Water balance, hydrograph, and soil moisture were simulated and compared to observed data. For streamflow calibration, the daily Nash‐Sutcliffe coefficient was 0.78 at the watershed outlet and 0.56 and 0.75 at the 2 nested subwatersheds. For the validation period, the Nash‐Sutcliffe coefficients were 0.79 at the watershed outlet and 0.85 and 0.83 at the 2 subwatersheds. The per cent bias was less than 15% for all sites. For soil moisture, the model also predicted the rising and declining trends at 4 of the 5 measurement sites. The spatial distribution of surface run‐off simulated by the model was mainly controlled by local characteristics (precipitation, soil properties, and land cover) on dry days and by global watershed characteristics (relative position within the watershed and hydrologic connectivity) on wet days when saturation excess run‐off was simulated. The spatial details of run‐off generation and travel time along flow paths provided by the model are helpful for watershed managers to further identify critical source areas of non‐point source pollution and develop best management practices.  相似文献   

Experimental characterization of the impact of temperature and humidity on the breakdown of soil water repellency in sandy soils and composts          下载免费PDF全文

Amii Whelan  Cedric Kechavarzi  Frederic Coulon  Stefan H. Doerr 《水文研究》2015,29(8):2065-2073

Soil water repellency is a widespread phenomenon with the capacity to alter hydrological and geomorphological processes. Water repellency decays with time, and the consequences are only of concern during the timescale at which the water repellency persists. This study aimed to characterize the influence of temperature and humidity on the breakdown of water repellency. Apparent contact angle measurements were carried out on samples consisting of sand treated with stearic acid as well as naturally repellent dune sands and composts. Temperature and humidity were controlled using a cooled incubator and a purpose designed enclosed box in which humidity could be raised or lowered. Results showed the contact angle of the stearic‐acid‐treated sands decayed with time and that there was a significant increase with stearic acid concentration. For all samples, the decay in apparent contact angle could be described with a continuous breakdown model. The stearic‐acid‐treated sands showed a significant increase in contact angle with relative humidity at a temperature of 10 and 20 °C. These differences diminished with increasing temperature. Similar results were seen for the dune sands and composts. Despite the influence of temperature and humidity on contact angles, there was no significant change in the rate at which the contact angle decayed in any sample. Absolute humidity was found to provide a more relevant indicator than relative humidity when assessing the influence of humidity on repellency over a range of temperatures. The contact angle initially increased with absolute humidity before plateauing owing to the confounding effect of temperature. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Seasonal variations in infiltrability of moss‐dominated biocrusts on aeolian sand and loess soil in the Chinese Loess Plateau     

Bo Xiao  Fuhai Sun  Xiaomeng Yao  Kelin Hu  Giora J. Kidron 《水文研究》2019,33(18):2449-2463

Biocrust effects on soil infiltration have attracted increasing attention in dryland ecosystems, but their seasonal variations in infiltrability have not yet been well understood. On the Chinese Loess Plateau, soil infiltrability indicated by saturated hydraulic conductivity (K_s) of biocrusts and bare soil, both on aeolian sand and loess soil, was determined by disc infiltrometer in late spring (SPR), midsummer (SUM), and early fall (FAL). Then their correlations with soil biological and physiochemical properties and water repellency index (RI) were analysed. The results showed that the biocrusts significantly decreased K_s both on sand during SPR, SUM, and FAL (by 43%, 66%, and 35%, respectively; P < .05) and on loess (by 42%, 92%, and 10%, respectively; P <.05). As compared with the bare soil, the decreased K_s in the biocrusted surfaces was mostly attributed to the microorganism biomass and also to the increasing content of fine particles and organic matter. Most importantly, both the biocrusts and bare soil exhibited significant (F ≥ 11.89, P ≤ .003) seasonal variations in K_s, but their patterns were quite different. Specifically, the K_s of bare soil gradually decreased from SPR to SUM (32% and 42% for sand and loess, respectively) and FAL (29% and 39%); the K_s of biocrusts also decreased from SPR to SUM (59% and 92%) but then increased in FAL (36% and 588%). Whereas the seasonal variations in K_s of the biocrusts were closely correlated with the seasonal variations in RI, the RI values were not high enough to point at hydrophobicity. Instead of that, the seasonal variations of K_s were principally explained by the changes in the crust biomass and possibly by the microbial exopolysaccharides. We conclude that the biocrusts significantly decreased soil infiltrability and exhibited a different seasonal variation pattern, which should be carefully considered in future analyses of hydropedological processes.  相似文献   

Quantification of river water infiltration in shallow aquifers using acesulfame and anthropogenic gadolinium          下载免费PDF全文

Andrea Bichler  Christian Muellegger  Robert Brünjes  Thilo Hofmann 《水文研究》2016,30(11):1742-1756

This study has investigated the use of the artificial sweetener acesulfame and the magnetic resonance imaging contrast agent gadolinium as quantitative tracers for river water infiltration into shallow groundwater. The influence of a river on alluvial groundwater in a subalpine catchment in western Europe has been assessed using the ‘classical’ hydrochemical tracer chloride and the trace contaminants acesulfame and anthropogenic gadolinium. Mixing ratios for riverine bank filtrate with ambient groundwater and the uncertainties associated with the temporal and spatial tracer variability were calculated using acesulfame and gadolinium and compared with those obtained using chloride. The temporal variability of tracer concentrations in river water of gadolinium (standard deviation SD: 63%) and acesulfame (SD: 71%) both exceeded that of chloride (SD: 27%), and this was identified as the main source of uncertainty in the mixing analysis. Similar spatial distributions were detected in the groundwater for chloride and gadolinium, but not for acesulfame. Mixing analyses using acesulfame resulted in calculated mixing ratios that differed from those obtained using gadolinium and chloride by up to 83% and 92%, respectively. At the investigated site, which had oxic conditions and moderate temperatures, acesulfame was found to be a less reliable tracer than either gadolinium or chloride, probably because of natural attenuation and input from other sources. There was no statistically significant difference between the mixing ratios obtained using chloride or gadolinium, the mixing ratios obtained using gadolinium were 40–50% lower than those obtained using chloride. This is mainly due to a bias of the mean gadolinium concentration in river water towards higher values. In view of the uncertainties of the two tracers, neither could be preferred over the other for the quantification of bank filtrate in groundwater. At this specific site gadolinium was able to reliably identify river water infiltration and was a more precise tracer than chloride at low mixing ratios (<20%), because of the exclusive occurrence of gadolinium in river water and its high dynamic range. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Effects of differing coverage of moss‐dominated soil crusts on hydrological processes and implications for disturbance in the Mu Us Sandland,China          下载免费PDF全文

Yongsheng Yang  Chongfeng Bu  Xingmin Mu  Kankan Zhang 《水文研究》2015,29(14):3112-3123

To study the effects of biological soil crusts (BSCs) on hydrological processes and their implications for disturbance in the Mu Us Sandland, the water infiltration, evaporation and soil moisture of high coverage (100% BSCs), middle coverage (40% BSCs) and low coverage (0% BSCs, bare sand) of moss‐dominated crusts were conducted in this study, respectively. The conclusions are as follows: (1) the main effects of moss‐dominated crusts in the Mu Us Sandland on the infiltration of rainwater were to reduce the infiltration depths and to retain the limited rainwater in shallow soil; (2) moss‐dominated crusts have no significant effects on daily evaporation when the volumetric water content at 4 cm depth in 100% BSCs (VWC4) was over 24.7%, on enhanced daily evaporation when the VWC4 ranged from 6.5% to 24.7% and on reduced daily evaporation when the VWC4 was less than 6.5%; and (3) decreasing the coverage of moss‐dominated crusts (from 100% to 40%) did not significantly change its effects on infiltration, evaporation and soil moisture. Our results demonstrated that for the growth and regeneration of shrubs, which were dominated by Artemisia ordosica in the Mu Us Sandland, high coverage of moss‐dominated crusts has negative effects on hydrological processes, and these negative effects could not be significantly reduced by decreasing the coverage of moss‐dominated crusts from 100% to 40%. Therefore, for the sustained and healthy development of shrub communities in the Mu Us Sandland, it is necessary to take appropriate measures for the well‐developed BSCs in the sites with high vegetation coverage in the rainy season. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Modelling landslides in unsaturated slopes subjected to rainfall infiltration using material point method          下载免费PDF全文

Samila Bandara  Alessio Ferrari  Lyesse Laloui 《国际地质力学数值与分析法杂志》2016,40(9):1358-1380

This paper presents a dynamic fully coupled formulation for saturated and unsaturated soils that undergo large deformations based on material point method. Governing equations are applied to porous material while considering it as a continuum in which the pores of the solid skeleton are filled with water and air. The accuracy of the developed method is tested with available experimental and numerical results. The developed method has been applied to investigate the failure and post‐failure behaviour of rapid landslides in unsaturated slopes subjected to rainfall infiltration using two different bedrock geometries that lie below the top soil. The models show different failure and post‐failure mechanisms depending on the bedrock geometry and highlight the negative effects of continuous rain infiltrations. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献