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1.
以西太湖湖滨典型河网区——宜兴大浦河网区为研究区域,对于该典型河网区与太湖之间的水量交换情况进行了系统的计算研究．考虑降雨因素的影响,采用考虑下垫面分类的产汇流模型,对各计算年内(2002年(基准年)．1998年(丰水年),1995年(平水年),1994年(枯水年))典型河网区及其西部山地区域的降雨径流过程进行了产汇流模拟．建立起适合该河网区域的非稳态河网水量模型,结合径流计算结果,对各年内典型河网区内水流的动态变化进行了计算模拟,对典型河网区与太湖水体的水量交换情况进行系统研究,分别对顺流与逆流情况下交换水量的年内分布与年际变化规律进行了分析． 相似文献
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基于熵值环境基尼系数法的平原河网区污染物总量分配 总被引：1，自引：0，他引：1
为制定科学合理的水污染物总量控制方案,以典型平原河网地区——张家港市为例,构建与人口、资源、经济和水污染物承受能力相协调的单因子环境基尼系数模型,并通过贡献系数判断引起不公平的主要污染物分配单元.利用熵值—环境基尼系数最小化模型,确定张家港市各乡镇基于多元公平性原则的氨氮总量分配方案.结果表明:在水污染物总量分配过程中,污染物削减比例的大小和污染物现状排放量之间并不具有一致性,最终的分配方案要综合考虑多方因素确定.本研究构建的熵值—环境基尼系数最小化模型综合考虑了研究区域社会、经济、资源等多种客观因素,对于平原河网地区,由于其特殊的地理位置和自然条件,人口、资源等分布相对比较均匀,故基于该模型所得到的分配方案充分表现了多元公平性原则,更公平合理. 相似文献
3.
以流经四川绵阳市安县河流茶坪河为研究对象,在对该河流水污染负荷、水环境现状及水环境功能充分调查的基础上,结合该河流的水文特征和排水规划以及四川省绵阳市环境监测站2005年实测的数据,采用二维浅水水动力学—水质模型方程组对茶坪河的各监测断面CODCr和NH3-N的浓度场进行了计算模拟和对比,并用一维水环境容量计算模型计算了该河流的水环境容量,提出了具体的总量控制措施.结果表明:用二维浅水水动力学—水质模型方程组计算各监测断面的CODCr和NH3-N与实测值相差不大;茶坪河水环境容量CODCr为123.96t/a,NH3-N为42.95t/a,所排放的CODCr量、NH3-N量已经超过该流域容量,出水水质已超过水质保护目标Ⅲ类标准. 相似文献
4.
徐雪峰 《CT理论与应用研究》2012,21(2):221-229
裂缝性致密砂岩的解释模型是测井定量评价的基础。依据黄桥地区龙潭组地层裂缝性致密砂岩地质特点和孔隙空间的组成,利用三水模型分析了裂缝性致密砂岩的导电机理,提出了该地区的测井解释理论和方法,实现了组分孔隙度和饱和度的定量计算。应用表明,计算的三水导电组分孔隙度与核磁共振测井结果一致,测井解释结果与测试结果一致,认为该方法适用于该地区裂缝性致密砂岩的测井评价。 相似文献
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地层水电阻率是水淹层精确识别的重要参数之一,对储层的定量评价起着关键性作用.在油田实际开发过程中,随着注入水一直在变化,地层水矿化度也随之发生改变,导致混合地层水电阻率与原始地层电阻率不一致,利用传统方法求取混合地层水电阻率结果误差较大,目前尚没有一个通用合理的广泛应用的方法,如何准确求取混合地层水电阻率成为国内各大高含水阶段油田面临的关键问题.从地层水的动态混合过程出发,提出一种基于离子交换的动态分析方法,其实质就是忽略注入水矿化度的变化性,将混合地层水分为无离子交换、离子交换完全以及离子交换未充分完成三个阶段,利用物质平衡方程和并联电阻关系式推导出计算模型,最终计算出混合地层水电阻率.利用该方法在大港油田G区块进行实际应用,将计算出的结果与利用自然电位资料计算方法的结果进行对比分析,结果表明:基于离子交换的水淹层地层水电阻率计算方法误差较小,有效的提高了计算精度,证实该方法的有效性,为实现水淹层的定量评价奠定了良好基础. 相似文献
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6 ka以来广州溺谷湾形成演变的数值模拟和地貌动力学分析 总被引：3，自引：0，他引：3
广州溺谷湾具有独特的地貌动力体系, 6 ka以来长期保持其活跃的水系. 为了探讨溺谷湾的地貌动力演变机制, 应用长周期数值模型对区域的水系和地貌演变进行了模拟和钻孔验证以及地貌动力分析. PRD-LTMM是一个本课题组自行研发的建立在流体运动方程和沉积物输运方程的基础上, 应用约简技术对模型输入和计算进行处理高分辨率(10 a)的千年尺度的长周期动力形态模型. 以193个可以明确辨识出最大海侵面的钻孔资料为基础, 重建了距今6 ka海进盛期的古珠江河口湾的水下地形, 并作为PRD-LTMM模型模拟的初始边界. 同时以广州溺谷湾中“门”这一独特的地貌动力单元作为切入点讨论广州溺谷湾的地貌动力的耦合演进过程. 模型计算结果应用27个测年钻孔资料进行验证, 其平均绝对误差为22.4%. 通过比较模型的计算结果与实际河网机构和口门相当符合, 表明PRD-LTMM的长周期模拟珠江河网、广州溺谷湾的形成和演变过程可行而且比较可信. 根据长周期模型的计算结果和地貌动力学分析表明: 广州溺谷湾的形态和“门”地貌单元是造成其活跃水动力的主导因素, 尤其是“门”地形所造成的双向射流系统的存在对广州溺谷湾的水系演变格局起了控制性的作用; 根据广州溺谷湾水动力结构、淤积过程和地貌形态的变化, 可将其演变划分为石门期、陈村期、黄埔期和珠江潮汐通道期. 相似文献
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平原河网多存在河道流动性不强,河道生态流速难以保障的问题,以典型平原河网地区——宁波市海曙区为例,开展野外原型同步监测,以河道分流比、换水率及槽蓄量为研究对象,系统分析引调水工程对河网水动力的调控效果.结果表明:平原河网水动力改善效果与引排水口分布、引水流量密切相关,为保证河网区水体交换良好,引排水口的连线应尽可能贯通整个区域;平原河网换水率在空间分布上具有很强的异质性(4种调水方案下河道换水率极差,最大为190%,最小为75%),引调水工程能够改善分流能力大的支汊的水动力特征,对分流能力小的支汊及断头河的水动力状况帮助不大;河网换水率提高、槽蓄量变化率减小是区域水动力改善的必要条件,海曙区较小的槽蓄量变化率为0.2%左右.本研究分析了河网区的河道输水能力以及换水率,对优化河网概化密度以减小模拟偏差有参考意义,为进一步探究平原河网水动力改善促进水环境质量提升提供基础,利于特殊水动力特征河道治理和区域水环境管控. 相似文献
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一种新型耗能剪力墙的滞回曲线计算分析 总被引：2，自引：0，他引：2
为了验证一种耗能剪力墙的抗震控制效果,本文进行了这种剪力墙模型的低周反复荷载试验。利用多垂直杆元模型建立了耗能剪力墙的力学计算模型,并利用该模型建立了计算耗能剪力墙荷载－位移骨架曲线和滞回曲线的计算方法,编制了相应的计算程序,利用该程序对试验进行了分析。计算曲线与试验曲线一致,表明本文采用的计算模型是正确的。 相似文献
10.
对于分布式水文模型而言,如何获得参数的空间分布是模型应用的重点和难点问题.本文将分水源参数中的敏感参数——自由水蓄水容量为研究对象.建立地形指数与自由水蓄水容量的函数关系,以此提取流域内的自由水蓄水容量空间分布.最后利用本方法提取了陕西省陈河流域的自由水蓄水容量空间分布,并将之作为栅格型新安江模型的参数进行洪水模拟演算.应用结果表明本文提出的方法得到了理想的模拟结果.该方法以物理规律为基础能较为准确地计算出流域内自由水蓄水容量的空间分布,为分布式模型的发展奠定了坚实的基础. 相似文献
11.
JÜRGEN R. SCHOPPER 《Geophysical Prospecting》1966,14(3):301-341
The knowledge of hydraulic and electric properties of porous media and the relations between them is essential for the quantitative evaluation of electric well logs and the solution of other reservoir engineering problems. The state of the art in this field is not yet satisfying. Theories still show considerable discrepancies with practice due to oversimplified model approaches. Empirical relations are either too coarse, not fully determined, or valid under specific geological and geographical conditions only. This article deals with the development of a general theory of the electric and hydraulic resistance behavior of porous media on the basis of a very general statistical network model. A general solution of the relations between formation factor, permeability, and porosity is presented by means of a rigorous mathematical treatment of two limiting cases of such a network. The solution shows that the product of the formation factor and the permeability can be expressed in the expectation values and the variation coefficients of pore channel cross section and shape factor and by a network factor, that depends on the mesh texture of the network. This network factor is in the range zero to one. It is further shown that the path length increase enters both the electric and the hydraulic tortuosity by its square. 相似文献
12.
突发地震灾害下，城市供水管网往往不可避免地会发生不同程度的破坏而导致城市供水功能的失效，对人们的生产生活产生了严重影响，快速对震后城市供水管网进行科学合理的功能修复，对于降低地震灾害损失具有重要意义。本文以城市供水管网为对象，针对震后管网系统功能评价及快速修复决策等问题进行了研究。在中国点式渗漏模型的基础上，采用基于破坏概率的渗漏面积计算方法，建立了考虑地震破坏随机性的管线渗漏流量计算模型；针对震后破坏管线展开了水力分析，并提出了以节点水头损失比为指标的节点服务性能失效状态量化方法；进而建立了震后管线的修复决策模型以及功能修复费用模型。研究成果可为震后功能修复工作中管线修复顺序及修复方案的优选提供科学依据，可显著提高震后应急救灾效率，实现城市供水功能的快速修复。 相似文献
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1 INTRODUCTION Evolution of the river bed in alluvial channels has been studied by many researchers using analytical and numerical approaches. The use of analytical approach alone is insufficient for solving natural river engineering problems. With rapid growth in computer technology, numerical models have become a popular means for the study of mobile bed hydraulics. During the past decade, several numerical models have been developed. Most of the computer codes, such as HEC2SR (Si… 相似文献
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A coupled one‐dimensional viscoelastic–plastic model for aquitard consolidation caused by hydraulic head variations in aquifers 
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下载免费PDF全文 T.‐L. Tsai 《水文研究》2015,29(22):4779-4793
Accurate and practical calculation of aquitard consolidation is required for a reliable analysis of land subsidence caused by groundwater overexploitation in a multilayered aquifer system because aquitards are generally more compressible than aquifers are. This study proposes a coupled one‐dimensional viscoelastic–plastic consolidation model that considers the combined effect of changes in soil parameters and body force to simulate aquitard consolidation caused by hydraulic head variations in neighbouring aquifers. The proposed model uses variable total stress and simultaneously solves hydraulic head and vertical soil displacement. The constitutive relation based on the Voigt model with different elastic moduli of the spring in normally consolidated and overconsolidated soils is used to describe the viscoelastic–plastic deformation mechanism of aquitards. In addition, the proposed model considers the combined effect of variations in hydraulic conductivity, elastic moduli, and body force on the calculation of aquitard consolidation. Three hypothetical scenarios with various hydraulic head variations in aquifers are used to examine the coupled one‐dimensional viscoelastic–plastic consolidation model. The results show that neglecting plasticity and viscosity of soil causes aquitard consolidation to be respectively underestimated and overestimated. In addition, ignoring body force variation underestimates aquitard consolidation, whereas neglecting soil parameters variation overestimates aquitard consolidation. Two real case scenarios are also studied to further demonstrate the applicability of the coupled one‐dimensional viscoelastic–plastic consolidation model. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
15.
Fractures in porous media have been documented extensively. However, they are often omitted from groundwater flow and mass transport models due to a lack of data on fracture hydraulic properties and the computational burden of simulating fractures explicitly in large model domains. We present a MATLAB toolbox, FracKfinder, that automates HydroGeoSphere (HGS), a variably saturated, control volume finite-element model, to simulate an ensemble of discrete fracture network (DFN) flow experiments on a single cubic model mesh containing a stochastically generated fracture network. Because DFN simulations in HGS can simulate flow in both a porous media and a fracture domain, this toolbox computes tensors for both the matrix and fractures of a porous medium. Each model in the ensemble represents a different orientation of the hydraulic gradient, thus minimizing the likelihood that a single hydraulic gradient orientation will dominate the tensor computation. Linear regression on matrices containing the computed three-dimensional hydraulic conductivity (K) values from each rotation of the hydraulic gradient is used to compute the K tensors. This approach shows that the hydraulic behavior of fracture networks can be simulated where fracture hydraulic data are limited. Simulation of a bromide tracer experiment using K tensors computed with FracKfinder in HGS demonstrates good agreement with a previous large-column, laboratory study. The toolbox provides a potential pathway to upscale groundwater flow and mass transport processes in fractured media to larger scales. 相似文献
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供水管网的抗震功能是指供水管网在地震作用下能够满足震后城市特定用水需要（需水量和水压）的能力。地震发生后,供水管网一般处于低压供水状态,使得管网中部分用户的水压和水量不能得到全部满足,导致管网部分节点的实际配水量小于需水量。为此,在传统的管网水力分析基础上考虑节点流量随节点水压的动态变化,通过求解非线性水力方程组,得到管网节点实际流量和水压;同时,借鉴结构可靠度分析方法,引入供水管网系统随机水力模型,给出了震后供水管网功能可靠度分析的一次二阶矩方法。以一实际管网为例,演示了震后低压供水时管网功能可靠度分析的应用方法。 相似文献
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The exponential decline in saturated hydraulic conductivity with depth: a novel method for exploring its effect on water flow paths and transit time distribution 下载免费PDF全文
下载免费PDF全文 The strong vertical gradient in soil and subsoil saturated hydraulic conductivity is characteristic feature of the hydrology of catchments. Despite the potential importance of these strong gradients, they have proven difficult to model using robust physically based schemes. This has hampered the testing of hypotheses about the implications of such vertical gradients for subsurface flow paths, residence times and transit time distribution. Here we present a general semi‐analytical solution for the simulation of 2D steady‐state saturated‐unsaturated flow in hillslopes with saturated hydraulic conductivity that declines exponentially with depth. The grid‐free solution satisfies mass balance exactly over the entire saturated and unsaturated zones. The new method provides continuous solutions for head, flow and velocity in both saturated and unsaturated zones without any interpolation process as is common in discrete numerical schemes. This solution efficiently generates flow pathlines and transit time distributions in hillslopes with the assumption of depth‐varying saturated hydraulic conductivity. The model outputs reveal the pronounced effect that changing the strength of the exponential decline in saturated hydraulic conductivity has on the flow pathlines, residence time and transit time distribution. This new steady‐state model may be useful to others for posing hypotheses about how different depth functions for hydraulic conductivity influence catchment hydrological response. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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This paper presents the analytical properties of the sensitivity of the two-dimensional, steady-state groundwater flow equation to the flow parameters and to the boundary conditions, based on the perturbation approach. These analytical properties are used to provide guidelines for model design, model calibration and monitoring network design. The sensitivity patterns are shown to depend on the nature of both the perturbed parameter and the variable investigated. Indeed, the sensitivity of the hydraulic head to the hydraulic conductivity extends mainly in the flow direction, while the sensitivity to the recharge spreads radially. Besides, the sensitivity of the flow longitudinal velocity to the hydraulic conductivity propagates in both the longitudinal and transverse directions, whereas the sensitivity of the flow transverse velocity propagates in the diagonal directions to the flow. The analytical results are confirmed by application examples on idealized and real-world simulations. These analytical findings allow some general rules to be established for model design, model calibration and monitoring network design. In particular, the optimal location of measurement points depends on the nature of the variable of interest. Measurement network design thus proves to be problem-dependent. Moreover, adequate monitoring well network design may allow to discriminate between the possible sources of error. 相似文献
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为进一步提高大地电磁非线性反演的稳定性、运算效率及准确度，将遗传神经网络算法引入大地电磁反演.首先针对大地电磁二维地电模型建立BP（Back Propagation）神经网络基本框架进行学习训练，网络输入为已知地电模型的视电阻率参数，输出为该地电模型参数；再利用遗传算法对神经网络学习训练过程进行优化，计算出多种地电模型网络连接权值和阈值的最优解；最后将最优连接权值和阈值对未知模型进行反演测试，网络输入为未知地电模型的视电阻率参数，输出为该地电模型参数.模型实验表明：遗传神经网络算法充分结合了遗传算法的全局寻优性和神经网络的局部寻优性，相比单一神经网络算法，在网络学习训练中提高了解的收敛成功率和计算速度，在反演测试中能更准确地逼近真实模型.将遗传神经网络算法与最小二乘正则化反演进行对比，理论模型和实测数据都验证了遗传神经网络算法在大地电磁反演中的可行性和有效性. 相似文献
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The use of detailed groundwater models to simulate complex environmental processes can be hampered by (1) long run‐times and (2) a penchant for solution convergence problems. Collectively, these can undermine the ability of a modeler to reduce and quantify predictive uncertainty, and therefore limit the use of such detailed models in the decision‐making context. We explain and demonstrate a novel approach to calibration and the exploration of posterior predictive uncertainty, of a complex model, that can overcome these problems in many modelling contexts. The methodology relies on conjunctive use of a simplified surrogate version of the complex model in combination with the complex model itself. The methodology employs gradient‐based subspace analysis and is thus readily adapted for use in highly parameterized contexts. In its most basic form, one or more surrogate models are used for calculation of the partial derivatives that collectively comprise the Jacobian matrix. Meanwhile, testing of parameter upgrades and the making of predictions is done by the original complex model. The methodology is demonstrated using a density‐dependent seawater intrusion model in which the model domain is characterized by a heterogeneous distribution of hydraulic conductivity. 相似文献