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1.
对滹沱河地下水库建设条件进行了分析,得出如下结论:滹沱河地下水库边界为一近封闭的边界,库容量达10.04×108 m3,滹沱河河床可作为地下水库天然渗漏场。通过入渗试验得出,在动水条件下,单位河长稳定入渗量为29.18×104 m3/km.d(平均河道宽度222m),入渗速率1.31×104 m3/m2.d,垂直入渗系数31.62m/d,入渗水对地下水的补给系数为0.91。利用库区原有的取水设施年开采能力可达2.19×108m3。根据预测结果,2020、2030年在不同的保证率下,尚有盈余水量进行地下水库的调蓄,且调蓄水源的水质对地下水水质影响不大。 相似文献
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通过大量的入渗试验,对不同地表条件下季节性冻融土壤的入渗特性进行了对比分析,结果表明:在冻融期,不同地表条件下土壤入渗能力均经历由高到最低点,然后再增高的变化过程;有覆盖物地块最小土壤入渗能力出现的时间均滞后于裸露地. 相似文献
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自制土槽试验装置,室内模拟低温水在河岸带土壤中非饱和入渗的过程。以填装中细砂为研究对象,进行了3种不同水头下的低温水入渗试验,对低温水在土壤中的入渗过程和水分、温度时空动态作了连续监测,分析了水头对入渗参数、水分场与温度场的影响规律。试验结果表明:在相同时间内,入渗水头越高,湿润锋垂直(水平)运移距离越大,垂直湿润锋的运移速度随入渗时间的增加有逐渐减少的趋势,最后逐渐趋于稳定;水头5 cm作用时入渗率波动较大,稳定时间大于水头25 cm和45 cm作用时土壤达到稳定入渗率所需的时间;入渗水头越高,平均温度下降越快,温度场也更快地达到相对稳态,水头25 cm在低温水入渗420 min后基本上达到稳态,水头45 cm在240 min后基本达到稳态。 相似文献
4.
降雨入渗条件下软岩边坡稳定性分析 总被引:7,自引:0,他引:7
降雨条件下软岩边坡的失稳模式是进行边坡处治的基本依据之一。为研究软岩边坡在降雨条件下的稳定性,提出了一种既能考虑渗流场对边坡稳定性的影响,又能体现岩石软化效应对边坡失稳所带来的不利作用的新方法。运用二维渗流数值计算方法,对降雨条件下的边坡孔隙水压力大小及暂态饱和区面积在空间及时间上的分布进行了模拟。并将渗流场计算结果与暂态饱和区岩石软化试验所得岩石物理力学参数随时间的取值相结合,采用强度折减法分析软岩边坡在降雨入渗条件下的稳定性。对算例边坡的研究表明:降雨入渗条件下软岩边坡的失稳在降雨初期表现为边坡表层局部分层垮塌。随着降雨历时的增长,失稳形式则表现为局部分层垮塌与整体滑移相结合。降雨停止后,边坡负孔隙水压力的消散,对软岩边坡安全系数的继续降低具有一定的延缓作用。 相似文献
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基于调蓄试验及数值模拟的北京市西郊地下水库人工补给效果评估 总被引:1,自引:0,他引:1
地下水库人工补给的效果评估对于水资源调蓄具有重要意义.本文利用回灌试验和数值模拟研究了北京市西郊地下水水库永定河河道入渗能力.结果表明在调蓄水源为3.30×108m3时,永定河河道入渗补给量为2.39×108m3,河道入渗率高这72.5%,调蓄能力强.三家店水库弃水后河道入渗影响范围为188 km2,对地下水补给效果明显.可见永定河河道是比较理想的人工调蓄场所,使得南水北调中线工程向北京输水后水资源在丰水年地下水人工补给成为可能. 相似文献
7.
谭菊萍 《前寒武纪研究进展》2013,(4):299-304
黄河冲积平原面积广大,农田灌溉频繁,灌水量大,在地下水资源评价时对灌溉入渗系数取值困难。本文在现场灌溉入渗试验的基础上,分析包气带岩性及结构、水位埋深、灌溉水量对灌溉入渗系数的影响,总结提出了多种条件下灌溉入渗系数的取值范围。在单位灌水量40~60m3/亩和水位埋深小于4m、4~8m、大于8m的井灌区中,当包气带岩性为粉土、粉砂时,灌溉入渗系数可分别取值0.21~O.10、0.10—0.05、0.05~0;当包气带岩性夹有粉质粘土层时,灌溉入渗系数可分别取值0.15~0.09、0.09—0.05、0.05~0。在单位灌水量较大的渠灌区,灌溉入渗系数可按单位灌水量的增大倍数而增加,由此为黄河冲积平原区地下水补给量计算中灌溉入渗系数的确定提供了依据。 相似文献
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针对石家庄市利用南水北调水和当地雨洪水作为补给水源建设滹沱河地下水库过程中存在受水区和水源区具有不同年际变化特征的实际情况,在分析南水北调水源区汉江流域和受水区石家庄市降水丰枯遭遇特征的基础上,应用模糊数学和多维联合分布概率计算方法计算滹沱河地下水库的模糊加权补给水量,并应用数值法模拟各种丰枯遭遇条件下地下水库的人工补给效果.结果表明:不同丰枯遭遇条件下的补给水量为(4.64~8.72)×108m3/a,其中模糊加权补给量为6.66×108m3/a;人工补给可使地下水位多年平均回升1.47~3.45 m/a;滹沱河地下水库的有效蓄水率为80%~90%,且人工补给的增大会引发侧向流出量增加,有效蓄水率相应降低. 相似文献
9.
自然电位方法可以应用于水文地球物理领域获取土壤水分入渗特征.通过连续监测野外试验场的自然电位场,获取连续的自然电位平面图,直接获知了土壤水分在平面上的主要入渗区域,同时借助自然电位成像方法,揭示了土壤水分的两个主要通道,并探测出两个地下孔洞的位置,最终在地质雷达剖面图的辅助下证实了上述结论,为水文地球物理领域提供了新的技术手段和方法. 相似文献
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An accurate determination of the hydrological characteristics of porous media, such as the values of the porosity and effective
porosity, are essential. This is important to understand the transport processes of infiltration and the movement of water
and contaminants in the porous media. In this study, a laboratory soil column experiment to estimate the porosity and effective
porosity of Toyoura standard sand samples, using a dielectric method termed the frequency domain reflectometry with vector
network analyzer (FDR-V), was performed. The FDR-V device uses high-frequency microwaves, ranging from 0.1 to 3 GHz, to measure
the complex dielectric constants of the sample. From the measured complex dielectric constant, the two parameters of the soil
samples then were derived, using a proposed dielectric mixture model and tracer concentration model. The effective porosity
of the soil sample is measured at 0.311 with the FDR-V dielectric method and 0.345 by the soil tracer column test. Comparing
this with the calculated porosities of the soil sample, the ratio of effective porosity is approximately 78% for the dielectric
method, and approximately 86% for the tracer concentration method. These different values can be explained to be within the
measurement range with regard to the measurement volume for the soil column. These results indicate that measurement by the
dielectric method using an FDR-V device is an efficient and useful tool for estimating the hydrological parameters of porous
media because of the dielectric response of earth materials. 相似文献
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Response parameters for characterization of infiltration 总被引:2,自引:2,他引:0
H. Rahardjo T. H. Ong R. B. Rezaur E. C. Leong D. G. Fredlund 《Environmental Earth Sciences》2010,60(7):1369-1380
Rainwater infiltration is of particular interest with respect to slope stability hazard management. The process of rainfall infiltration into unsaturated soil is complex due to the number of soil parameters involved and the random nature of moisture flux boundary conditions. In this paper, the effect of rainfall intensity on infiltration is investigated through the use of finite element seepage modeling for a 5 m high soil column subjected to various rainfall intensities. The numerical modeling study identified three response parameters that can be used to describe one-dimensional infiltration into an unsaturated soil. The response parameters are the depth of wetting front, the matric suction reduction depth, and the sectional infiltration rate. The practical application of the rainfall response parameters in slope stability analysis is illustrated. 相似文献
14.
在室内模拟降雨试验的基础上,利用多重相互作用连续体(MINC)组件,对含砾石土壤降雨入渗过程进行了数值模拟,以期深入理解含砾石土壤中的水土过程.研究结果表明,土壤中砾石的存在能够导致土壤水分饱和度增加,使得土壤总入渗量以及降雨入渗深度降低.含砾石土壤中存在一个陡的湿润锋面,在湿润锋面上土壤水分饱和度急剧下降.MINC组件可以很好地模拟含砾石土壤降雨入渗过程,其对含砾石土壤湿润锋和土壤含水率变化的模拟值与实测值吻合较好.降雨期间土壤水分饱和度沿土壤剖面的变化可用来解释含砾石土壤降雨入渗深度降低的原因. 相似文献
15.
Analysis of time-varying rainfall infiltration induced landslide 总被引:5,自引:0,他引:5
Chen Chien-Yuan Chen Tien-Chien Yu Fan-Chieh Lin Sheng-Chi 《Environmental Geology》2005,48(4-5):466-479
A case study of rainstorm-induced landslide is modeled following the hourly rainfall time series from the stage of infiltration
caused by induced slope movement and soil saturated to excess pore pressures—Transient Rainfall Infiltration and Grid-based
Regional Slope-Stability Analysis (TRIGRS). The grid-based landslide stability analysis was conducted to model the increased
pore pressures and runoff in the study area under the specified rainfall conditions. The generated time variances of pore
pressures help determine landslide characteristics and mechanisms under rainfall conditions. Inputs of soil properties and
permeability parameters for landslide stability analysis in the study area were prepared by TRIGRS adopted for transient infiltration
analysis. Results of the analyses show that under heavy rainfall conditions, the infiltrated slope is unstable and the time
of debris masses movement initiated is correlated to the recorded time. In the initiated landslide, characteristics and effects
are considered and reflected in the numerical modeling under combinations of topography, land use, climatic and geological
conditions. Results reveal that there is a plane failure surface and a potential circular failure surface at the study site
besides the rock topple failures in the crest. A grid-based slope-stability analysis incorporated with the GIS spatial functions
is more advantageous than the traditional two-dimensional analysis for specified slope profiles to determine the whole behavior
of a slope. 相似文献
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《International Geology Review》2012,54(1):100-109
In infiltrational uranium deposits in the zone of supergenesis, uranium ores occupy a definite position within the epigenetic zonation series arising in consequence of paragenetic changes imposed upon the already formed rock and succeeding each other spatially in an orderly sequence. The following four zones were determined and mapped: the zone of surficial oxidation in the outcrops themselves; the zone of horizontal oxidation, along aquifers and below the ground water table, invariably confined between some two epigenetically unaltered water-impervious horizons; the zone of uranium accumulation over unoxidized rocks and in contact with the zone of horizontal oxidation (this zone consists of three sub-zones; gray low-grade ores, black ores, gray ores); unoxidized rocks. — IGR Staff. 相似文献
18.
暴雨型滑坡降水入渗机理分析 总被引:11,自引:1,他引:10
暴雨能诱发大量的滑坡发生,在不同地区存在不同的临界降雨值,每当雨强大于该值时,滑坡就会大面积发生,这已经被多起滑坡事件证实。一般地,入渗理论认为,当雨强大于一定值时,入渗率是常量,过强的降水会转化为地表径流,这与雨强越大滑坡越易发生、群发性越强的观察结果不一致。在斜坡体上存在大量的裂隙,它们对降水入渗有着很大的贡献,应用有限单元法分别模拟了有裂隙和无裂隙时斜坡体内瞬态渗流场的变化,并用Bishop法对不同埋深滑动面的稳定性做了计算分析。模拟结果表明:考虑裂隙时的计算结果与宏观观察结果更一致,在评价降雨入渗对斜坡稳定性的影响时,一定要充分考虑裂隙的存在,只有雨强大于一个临界值时才会有充足的降水通过裂隙渗入到斜坡深部,裂隙的影响才显著地表现出来。 相似文献
19.
非饱和土壤Richards方程入渗求解探讨 总被引:3,自引:0,他引:3
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
20.
Three modes of rainfall infiltration inducing loess landslide 总被引:4,自引:1,他引:3