共查询到19条相似文献，搜索用时 531 毫秒
1.
为了更加准确地确定含水层参数,提出了利用地下水流数值模拟软件Modflow耦合大型抽水试验和长观孔水位两个模型的方法,对含水层参数进行了识别与校验。该方法求得的含水层参数避免了只利用抽水试验模型校验所带来的不确定性,同时利用抽水实验数据进行抽水与恢复的全过程曲线拟合,水位降深模拟相对误差小于6%,提高了含水层参数的准确性。 相似文献
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确定含水层参数的全程曲线拟合法 总被引：9，自引：3，他引：6
含水层参数的确定是地下水资源评价、数值模拟、开发利用与保护以及科学管理的重要基础,抽水试验法是确定含水层参数的主要方法。根据含水层抽水试验的泰斯（Theis）公式,运用优化理论,结合计算机技术,提出利用抽水试验数据确定含水层参数的全程曲线拟合法。该方法充分考虑抽水过程中水位快速下降段、水位缓慢下降段和水位恢复段的观测资料,满足计算水位与实测水位之间的误差平方和最小、计算的水位过程线与抽水过程的实测曲线最佳拟合。实例研究表明,该方法速度快、精度高、求参结果最优,既适用于承压含水层求参,又可推广到潜水含水层求参。 相似文献
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为求取含水层水文地质参数,常用的试验方法是抽水试验。在进行抽水试验时,经常有越流现象,计算时一般采用越流模型计算。越流模型假定非抽水含水层的水位恒定不变,但在实际抽水过程中,抽水含水层和非抽水含水层间通过越流相互影响、相互作用。如果只考虑抽水含水层的水位变化而不考虑非抽水含水层的水位变化,会导致计算的水文地质参数不准确。实际工作中,有时会在非抽水含水层中布置一口观测井来观测抽水含水层抽水时对非抽水含水层的影响。如果采用多层含水层系统模型的方法,即可利用各含水层观测井中的数据计算出每个含水层和相关弱透水层的水文地质参数,提高参数计算精度、节省资金和工作量。 相似文献
4.
抽水含水层对非抽水含水层水位影响的效应分析 总被引：3，自引：0，他引：3
利用自动水位计记录的抽水试验过程中不同层位含水组之间的动态水位,分析了在抽水试验最初阶段时抽水含水组与非抽水含水组之间的水力联系。研究结果表明:(1)抽水含水层对非抽水含水层存在水位影响效应,在抽水初期,水位影响效应较大;当抽水含水层水位达到稳定或缓慢下降时,水位影响效应随之消失。(2)单位降深水位影响效应显示,上部含水层距离抽水含水层越远,水位影响效应越大;下部含水层距离抽水含水层越远,水位影响效应越小。(3)利用三维地下水流数值模拟方法和应力应变对含水层水位动态影响的原理对水位影响效应机理进行分析,发现水位影响效应与含水层的固体骨架压缩系数(α)、水体积压缩系数(β)、孔隙度(n)和边界控制系数(Cm)等参数有关。 相似文献
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含水层的水文地质参数是进行地下水资源计算、地下水污染防控等所必需的基础数据,结合数值模拟技术进行含水层参数反演很有必要.按照1:5万水文地质调查规范在江汉平原仙桃市杨林尾镇复兴水厂不同含水层位开展抽水试验,包括深层含水层单孔抽水试验以及浅层含水层中群孔(2孔)抽水试验.对于单孔抽水试验,应用第1类越流系统井流理论进行参数反演;对于群孔抽水试验,推导了特定综合井函数,并利用特定标准曲线匹配法和直线图解法求解了含水层参数.随后利用FEFLOW软件建立了相应数值模型,拟合了含水层参数.结果表明:浅层含水层的渗透系数变化范围为21.66~54.00 m/d,贮水率变化范围为1.28×10-5~8.00×10-4 m-1;深层含水层渗透系数变化范围为1.27~7.00 m/d,贮水率变化范围为3.90×10-6~5.00×10-6 m-1.对于深层承压含水层而言,越流补给量较大.采用数值模拟方法结合抽水试验数据求参,综合考虑了含水层结构,拟合效果好,所得结果更加可靠. 相似文献
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矿井采煤对地下水环境的影响主要为对具有供水意义的含水层水位及水量产生影响,确定采煤引起地下水水位降及漏失量是煤矿地下水环境影响评价的关键。以纳林河矿区某大型矿井为例,运用Visual MODFLOW建立模拟区地下水流数值模型,利用实测流场和长观孔的动态观测资料识别和验证数值模型,利用模型来预测采煤对第四系-白垩系含水层水位及水量的影响。模拟结果显示:前25年采煤引起地下水最大水位降为3.6 m,引起地下水的漏失量最大为141.87万m^3/a,占矿井涌水量的29.88%;利用矿化度法确定的越流量占矿井涌水量的6.39%~34.89%,模拟结果基本合理,可作为矿井采煤对地下水环境影响的研究依据。 相似文献
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为了探究水文地质结构对地下水流数值模拟的不确定性,可以运用随机模拟建立地下水位的预测模型。根据转移概率地质统计方法模拟多孔介质岩性分布,利用非线性规划的思路计算岩性与水文地质参数之间的关系,从而建立相对精确的随机水文地质参数场。将不同的水文地质参数场运用到MODFLOW中,得到不同的随机模拟结果。通过比较随机模型和确定模型的末流场拟合情况以及水位动态拟合图,发现确定模型和随机模型具有相似趋势,都能与实测流场拟合较好,但是随机模型更能体现真实的水文地质特征。对随机模型预测10年后的地下水水位做不确定性分析,得到水位平均变幅介于-5～5 m之间,且95%置信度水位变幅的平均上限线约为0.146 m。研究结果为决策者提供科学依据。 相似文献
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为了获取裂隙含水层水文地质参数,以黑龙江省七台河市应急水源地为例,在抽水试验和示踪试验基础上,利用数值模拟软件GMS(Groundwater Modeling System)建立地下水流数值模型和溶质运移模型。通过研究溶质运移单域模型和两区模型,发现在裂隙含水层中两区模型能更好的描述穿透曲线的拖尾现象。实例研究表明利用数值模拟方法反演的含水层参数与解析法结果很接近,数值模拟的水均衡误差为0.024%,参数可靠性较高。研究发现该地区裂隙连通性较好,可作为应急水源地。 相似文献
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煤矿疏降水工程需要以含水层组参数为基础进行合理布设。结合某矿区内的非稳定流双孔干扰抽水试验,在无观测孔情况下,根据抽水井资料分别利用通用直线法、水位恢复法、解析法及优化拟合四种方法确定承压含水层的导水系数,并利用后期疏降水孔资料对上述方法进行验证,结果表明通用直线法和水位恢复法计算结果可靠。 相似文献
11.
The origin and movement of groundwater are the fundamental questions that address both the temporal and spatial aspects of ground water run and water supply related issues in hydrological systems. As groundwater flows through an aquifer, its composition and temperature may variation dependent on the aquifer condition through which it flows. Thus, hydrologic investigations can also provide useful information about the subsurface geology of a region. But because such studies investigate processes that follow under the Earth's shallow, obtaining the information necessary to answer these questions is not continuously easy. Springs, which discharge groundwater table directly, afford to study subsurface hydrogeological processes.The present study of estimation of aquifer factors such as transmissivity (T) and storativity (S) are vital for the evaluation of groundwater resources. There are several methods to estimate the accurate aquifer parameters (i.e. hydrograph analysis, pumping test, etc.). In initial days, these parameters are projected either by means of in-situ test or execution test on aquifer well samples carried in the laboratory. The simultaneous information on the hydraulic behavior of the well (borehole) that provides on this method, the reservoir and the reservoir boundaries, are important for efficient aquifer and well data management and analysis. The most common in-situ test is pumping test performed on wells, which involves the measurement of the fall and increase of groundwater level with respect to time. The alteration in groundwater level (drawdown/recovery) is caused due to pumping of water from the well. Theis (1935) was first to propose method to evaluate aquifer parameters from the pumping test on a bore well in a confined aquifer. It is essential to know the transmissivity (T = Kb, where b is the aquifer thickness; pumping flow rate, Q = TW (dh/dl) flow through an aquifer) and storativity (confined aquifer: S = bSs, unconfined: S = Sy), for the characterization of the aquifer parameters in an unknown area so as to predict the rate of drawdown of the groundwater table/potentiometric surface throughout the pumping test of an aquifer. The determination of aquifer's parameters is an important basis for groundwater resources evaluation, numerical simulation, development and protection as well as scientific management. For determining aquifer's parameters, pumping test is a main method. A case study shows that these techniques have been fast speed and high correctness. The results of parameter's determination are optimized so that it has important applied value for scientific research and geology engineering preparation. 相似文献
12.
观测孔井位的选取在抽水试验中具有极其重要的作用。在目前实际工作中,只是定性的选择观测孔井位,决策缺少可靠性和客观合理性。该文通过建立优选抽水试验观测孔井位的多目标多层次系统模糊决策模型,综合考虑影响观测孔井位确定的观测孔与抽水孔的连线方向与地下水流方向所成的锐角度数、水文地质影响因素和观测孔与抽水孔之间的距离三项主要因素以及含水层埋深、含水层厚度和岩性三项水文地质影响子因素,优选了观测孔井位;并利用西龙河峄山断层带水源地抽水试验资料对该模型进行了验证。结果表明:采用该措施使通常的选择分析由定性描述转向定量决策,避免了主观判断偏差,有助于决策判定,所得结果是可靠的。 相似文献
13.
Development of a simple method for determining the influence radius of a pumping well in steady-state condition 
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下载免费PDF全文 A S El-Hames 《地下水科学与工程》2020,8(2):97-107
Influence radius of a pumping well is a crucial parameter for hydrogeologists and engineers. Knowing the radius of influence for a designed drawdown enables one to calculate the pumping rate required to layout a project foundation that may need lowering of groundwater level to a certain depth due to dewatering operation. In addition, this is important for hydrogeologists to determine ground water contamination flow paths and contributing recharge area for domestic water supply and aquifer management purposes. Empirical formulas that usually neglect vital parameters to determine the influence radius accurately have been traditionally utilized due to lack of adequate methods. In this study, a physically based method, which incorporates aquifer hydraulic gradient for determining the influence radius of a pumping well in steady-state flow condition, was developed. It utilizes Darcy and Dupuit laws to calculate the influence radius, where Darcy's law and Dupuit equation, in steady-state condition, represent the inflow and the outflow of the pumping well, respectively. In an untraditional manner, this method can be also used to determine aquifer hydraulic conductivity as an alternative to other pumping test methods with high degree of accuracy. The developed method is easy to use; where a simple mathematical calculator may be used to calculate the influence radius and the pumping rate or hydraulic conductivity. By comparing the results from this method with the MODFLOW numerical model outputs with different simulated scenarios, it is realized that this method is much superior and more advantageous than other commonly used empirical methods. 相似文献
14.
抽水试验是确定含水层参数及了解水文地质条件的一项重要方法,采用非稳定流直线图解法和水位恢复法对某水源地的抽水试验资料进行分析计算,根据水源地运行后的水位以及出水量资料来分析确定其水文地质参数。 相似文献
15.
注水问题的含水层位移模型求解的难点在于边界条件的恰当处理。根据Theis定流量抽水与注水水流模型的反对称特性,假定注水位移模型的无限远通量边界与抽水位移模型的无限远通量边界也具有反对称性,从而得到Theis定流量注水的含水层位移模型解答,发现定流量注水与抽水的含水层骨架颗粒位移速度、累计位移量、径向应变及切向应变的解答均互为反号值。注水过程中含水层在径向有两种形变区,依次为膨胀区和挤压区。在膨胀区和挤压区的界限处,径向位移取得最大值。如果假定含水层顶底板不动,注水导致的地层相对位移足以产生水井或油井套管变形和折断破坏。注水时含水层在切向处于恒拉张状态,这可能导致井壁围岩产生径向放射状张裂缝。 相似文献
16.
C. C. Bicalho C. Batiot-Guilhe J. L. Seidel S. Van Exter H. Jourde 《Environmental Earth Sciences》2012,65(8):2311-2319
The Lez karst spring, located in the Mediterranean basin (southern France) supplies drinking water to the metropolitan area
of Montpellier (France) since the nineteenth century. Since 1981, an intense pumping is being performed directly in the main
conduit with a maximum exploitation flow rate of about 1,700 l/s. To improve the understanding of groundwater origins and
circulation dynamic in this karst system, as well as the impact of three decades of intense water exploitation, groundwater
samples have been collected during various hydrologic conditions since March 2006. A previous hydrochemical study on the Lez
karst system had been carried out before the installation of the pumping plant. This dataset was compared to the present one
to identify possible changes on groundwater hydrochemistry. The results of this analysis indicate the existence of historical
changes in water hydrogeochemistry and evidence a decrease of the deep compartment participation to the Lez spring outflow.
This change in spring water hydrogeochemistry may be attributed to the intense pumping of the karst system and, in the absence
of noticeable climatic changes, expresses the direct consequences of anthropogenic forcing on the overall functioning of the
aquifer. This study aims to analyze the differences, to understand the water chemistry changes and to better foresee the aquifer
evolution for the future. 相似文献
17.
无限承压含水层中主孔涌水多孔观测定降深井流试验水文地质参数计算 总被引：4，自引：1，他引：3
利用自溢井(孔) 做放水试验确定含水层水文地质参数, 是简便而经济的确定含水层水文地质参数的试验方法.涌水试验基本上属于定降深井流试验.在无限承压含水层中进行涌水试验, 使涌水孔(井) 降深sw保持不变, 涌水量随时间的延续而减少, 除涌水孔(井) 本身以外, 含水层中任意点的水头H随时间的延续而降低.在单孔(井) 定降深井流试验利用涌水孔1/Q-lg t直线图解法计算水文地质参数的基础上, 建立一孔(主孔) 涌水多孔观测水位降低的直线图解法, 即s/Q-lg t直线图解法. 相似文献
18.
磁共振探测估算含水层渗透系数的原位试验研究 总被引：1，自引：0，他引：1
通过一个完整的磁共振探测（MRS）、钻探、抽水试验过程,开展了MRS估算含水层渗透系数的原位试验研究。在分析MRS估算渗透系数准确性的基础上,系统剖析了引起准确性差异的主要因素,并对进一步提高估算效果提出了建议。结果显示：（1）采用现阶段常用的参数设置,与抽水试验计算值相比,MRS估算渗透系数的差值为抽水试验计算值的17.59%。（2）MRS推断的含水层顶板、底板埋深与钻孔揭示的信息相比,差值分别为4.11m、1.03m,表明其对估算渗透系数准确性的影响较小。（3）CP值是影响估算准确性的重要因素,其值为10-9数量级符合大多数地层的特点。另外,通过在已知渗透系数的钻孔附近进行MRS,从而获取CP参考值,应用该值估算的渗透系数准确性高于常用的参数设置。（4）指数a、b设置方面,应用Seevers公式（a=1、b=2）的估算效果优于Kenyon公式（a=4、b=2）。本成果有助于提高MRS估算渗透系数方法在野外条件下的适用性。 相似文献
19.
以单井抽水试验资料为基础,计算出该区的新近系砂砾岩含水层的出水量为40m^3/h。为解决水源热泵系统的热源及同层回灌问题,进行了较长时间的带有观测孔的抽水试验及回灌试验。试验表明：该区的渗透系数为32.16m/d,影响半径为166m,回灌渗透系数为14.38m/d,回灌影响半径为61m。据此计算干扰井单井抽水量为38.51m^3/h,干扰井单井回水量为11.14m^3/h,同时确定该区的抽灌井比例为1∶4。根据用水需求,该区设计抽水两口,回灌井8口,备用一口回灌井,形成该区的水源热泵系统。系统运行近两年来,单井出水量、回灌量及水位降深均符合设计要求,达到了预期效果。 相似文献