潮汐对地下水波动影响的数值模拟

本文从经典的Boussinesq方程出发，在考虑浸润面影响的基础上，建立了基于有限差分法的滨海地区一维地下水运动数值模型。通过将潮汐运动概化为正弦波，模拟了滨海地区地下水水位随潮汐波动的变化。结果显示，地下水水位的波动相对于潮汐波动来说具有不对称性、振幅衰减以及相位滞后等特征。通过比较受潮汐影响的地下水平均水位与不考虑潮汐影响的地下水水位发现，实际的地下水平均水位要高于未考虑潮汐影响的地下水水位。最后数值模拟了浸润面的形成和消失的过程。     

潮汐对沿海潜水水位的影响研究

沿海潜水地下水水位受到潮汐海平面的振动影响而上下波动,而地下水水位的位置与沙滩的稳定性和海水入侵有密切的联系。通过潮汐对沿海地下水水位影响的方程形式的概述,综述了在解析解与数值解方面的研究进展,并在此基础上提出了潮汐影响下地下水水位变化的3个特征:振动不对称性、振幅有衰减、相位滞后。     

波浪作用下缓坡近岸海域沿岸流分布影响因素分析

本文研究了均匀岸坡地形条件下．规则波及不规则波浪作用下缓坡近岸海域沿岸流的分布规律。采用数学模型与物理模型相结合，分析了波浪要素，地形坡度等因素对沿岸流分布的影响。提出了表征沿岸流分布特征参数的经验公式。研究结果表明，缓坡近岸海域，波浪作用下沿岸流的分布主要受到入射波浪波高、入射角度及地形坡度的影响。不规则波浪作用下沿岸流的速度分布相对平缓。     

莱州湾南岸海底地下水交换量研究

相对于定性研究海水入侵的程度及规律,定量研究能更直观的给出海水入侵地区的SGD(Submarine groundwater discharge)以及流入量。选择潍坊昌邑市北部潮间带地区,布设3km长监测剖面,通过监测地下水水位、水温、以及电导率数据,运用数学方法定量估算海底地下水交换量。同时,运用计算所得结果,对研究区海水入侵情况进行评估,为将来该地区地下水监测提供科学依据。计算结果表明,潮间带流入量明显大于流出量,海水呈现朝陆推进趋势。     

MODEL OF SEA ICE BREAKUP ON SHALLOW BEACH DUE TO TIDAL FLUCTUATION

1.　 INTRODUCTIONThe breakup ofice isthe basis to analyze the mechanism of ice ride-up and pile-up,andto further study the formation of rafted ice and ice ridge.Up till now,researcheshave focused on the effectof wind and currenton shore fasticebreakup.Christensen F.T.[1 ] analyzed the possible size ofthe ice pieces when the ice floe in-teracts with the slope underthe action of wind and currentdriving forces.S rensen C.[3] in-vestigated the failure of a floating ice floe when itcollided w…     

EXPERIMENTAL INVESTIGATION OF EFFECT OF TIDE ON COASTAL GROUNDWATER TABLE

In this article,a tide simulation system based on a two-way water pump technique is developed.Using this system and numerical simulations,the groundwater table fluctuation characteristics,relative over height of groundwater table,and influencing factors of over height are investigated.The experimental and numerical results indicate that the groundwater table fluctuation is of periodic,and of asymmetric.The amplitude of groundwater table fluctuations decreases with the increase of the onshore distances.There...     

Modeling Groundwater Flow and Seawater Intrusion in the Coastal Aquifer of Wadi Ham,UAE

Groundwater pumping from Kalbha and Fujairah coastal aquifer of the United Arab Emirates (UAE) has increased significantly during the last two decades to meet the agriculture water demands. Due to the lack of natural replenishment from rainfall and the excessive pumping, groundwater levels have declined significantly causing an intrusion of seawater in the coastal aquifer of Wadi Ham. As a result, many pumping wells in the coastal zone have been terminated and a number of farms have been abandoned. In this paper, MODFLOW was used to simulate the groundwater flow and assess the seawater intrusion in the coastal aquifer of Wadi Ham. The model was calibrated against a five-year dataset of historical groundwater levels and validated against another eleven-year dataset. The effects of pumping on groundwater levels and seawater intrusion were investigated. Results showed that reducing the pumping from Khalbha well field will help to reduce the seawater intrusion into the southeastern part of the aquifer. Under the current groundwater pumping rates, the seawater will continue to migrate inland.     

潮汐引起滨海承压含水层地下水位变化的数值模拟

海潮波动可以引起海岸带地下水位发生波动。建立基于有限差分法的滨海地区一维承压含水层地下水运动数值模型。通过将潮汐波动概化为正弦波,模拟滨海地区地下水位随潮汐波动的变化。结果表明,受海潮影响的滨海含水层地下水位与海潮有相似的波动特征,但变幅减小,受海潮的影响程度与离海岸的距离有关,随着离海岸距离的增加地下水位的变幅及潮汐效率呈负指函数衰减,地下水位对海潮的滞后时间随距离呈线性增加。例如,当承压含水层导水系数为31．25m^2／h、储水系数为4．5×10^-4及海潮振幅为2．5m、周期为24．7h时,在距离海岸500m处,振幅为1．35268m,潮汐效率为0．54107,滞后时间为1．825h。在距海岸达4389m以远时可以认为地下水位不受海潮波动的影响。     

地震作用下渗流边坡的动力响应耦合分析

运用有限差分软件FLAC3D,建立某一赋含地下水的顺层岩质边坡三维模型,基于Finn动孔压增长模型,对边坡在地震作用下的加速度响应规律作了流固耦合分析,并就地下水对边坡塑性区分布的影响作了简要分析。数值计算结果表明:含地下水边坡的地震动峰值加速度PGA放大系数和坡顶加速度均大于无水边坡,地下水位升高时,PGA放大系数和坡顶加速度呈波动变化,当边坡土体处于完全饱和状态时,两者均明显增大;坡脚加速度随水位变化也呈波动状态,当边坡土体处于完全饱和状态时,同样明显增大;含地下水边坡的PGA放大系数等值线比不含地下水时的曲线分布更为杂乱,规律性较差,但仍具有明显的加速度垂直放大效应和临空面放大效应;表面风化层的塑性区随水位升高,其拉剪共同作用破坏单元逐渐增加,表面边坡的破坏效应逐渐增大。综合加速度、坡顶位移和塑性区分布来看,地下水对地震作用下顺层岩质边坡的稳定不利。     

分层型河口咸水上溯对径流潮汐共同作用的基本响应

为探究径流主导分层的河口中径流潮汐共同作用对半月周期咸水上溯距离的影响,采用概化河口对分层型咸水运动进行了三维数值模拟试验。结果表明:恒定径流量下,半月周期咸水逐日最大上溯距离表现为随潮差顺时针围绕准平衡态变化的绳套曲线,径流量越小,与准平衡态差距越大,且小潮后强烈上溯持续的时间更长,退落也更迅速;分层混合过程的时效性导致咸水运动半月周期非线性调整,在文中概化条件下,咸水状态普遍具有最大上溯发生在最小潮后2~3d和最小上溯发生在最大潮后1~2d的时间特征;根据咸水运动的规律确立工程措施中增流压咸时机,在小潮时增加上游径流量并持续7d至大潮,然后利用半月周期咸水自然退落,可达到明显压咸效果,节约枯季上游淡水资源。     

滨海盆地变密度地下水流与溶质运移三维耦合数值模型研究

针对滨海含水层的复杂性,以北部湾经济区合浦盆地地下水资源应急潜力评价为例,通过概化出合浦盆地水文地质概念模型的基础上,采用SEAWAT模块建立了合浦盆地变密度地下水流与溶质运移三维耦合数值模型。在对模型进行识别、验证的基础上,假设2025年10月出现极端干旱,在保证不发生海水入侵的条件下,获得了度过整个枯水期各水源地地下水资源应急潜力。结果表明:合浦盆地地下水资源应急潜力为83.13万m~3/d,集中开采区中心地下水水头下降3～8 m, 2 a后水位基本恢复;集中开采区降落漏斗远离海岸线,不受到海水入侵的影响。该方法将滨海水源地地下水应急供水预测和盆地的水文地质结构及当地发展规划紧密结合起来,为合浦盆地地下水资源的合理开发利用和应急能力建设提供了可靠依据。     

Influences of coastal underground reservoir construction and utilization on saltwater and freshwater transport law in aquifersEI北大核心CSCD

In order to reveal the impact of underground reservoir construction and extraction methods on the saltwater and freshwater transport law in coastal aquifers, a 300m × 900m × 30m conceptual numerical model was established. The variable density current simulation method of unconfined aquifer was used to analyze the saltwater and freshwater transport law in coastal aquifer under different extraction scenarios before and after the construction of underground dam. The results show that the construction of underground dam can significantly reduce the scope and degree of seawater intrusion. Groundwater extraction can accelerate the intrusion and diffusion of residual saltwater in underground reservoirs within a certain time range. The coefficient of saltwater intrusion is exponentially related to extraction scale and the distance between extraction wells and underground dams. Reasonable layout of the location and scale of extraction wells can effectively reduce the negative impact of groundwater extraction on water salinity in the reservoir area. © 2023, Editorial Board of Water Resources Protection. All rights reserved.     

海河平原区浅层地下水位健康修复目标研究

随着南水北调通水、地下水超采综合治理等措施实施,海河平原区地下水位下降态势得到初步缓解,在此背景下,如何确定地下水位修复目标十分迫切。本研究在已有生态地下水位概念基础上,提出适应于强人类活动区-海河平原区的健康地下水位概念,并将健康地下水位作为研究区地下水位修复目标。根据地下水位波动变化对生态环境的影响,将健康地下水位分为维持地表水体健康地下水位、遏制海水入侵地下水位等七类功能型健康地下水位,在现有研究方法和研究成果基础上,采用机理研究、统计分析、实践调查等方法确定各功能健康地下水位临界阈值。研究建立了兼顾地下水多功能属性的空间分布式健康地下水位量化方法,确定了海河平原区健康地下水位上限和下限。并对海河平原区现状地下水位健康状态进行诊断,依据诊断结果建立地下水管理分区,为研究区水资源管理提供支撑。     

Uncertainty analysis of seawater intrusion forecasting

In order to describe the importance of uncertainty analysis in seawater intrusion forecasting and identify the main factors that might cause great differences in prediction results, we analyzed the influence of sea level rise, tidal effect, the seasonal variance of influx, and the annual variance of the pumping rate, as well as combinations of different parameters. The results show that the most important factors that might cause great differences in seawater intrusion distance are the variance of pumping rate and combinations of different parameters. The influence of sea level rise can be neglected in a short-time simulation （ten years, for instance）. Retardation of seawater intrusion caused by tidal effects is obviously important in aquifers near the coastline, but the influence decreases with distance away from the coastline and depth away from the seabed. The intrusion distance can reach a dynamic equilibrium with the application of the sine function for seasonal effects of influx. As a conclusion, we suggest that uncertainty analysis should be considered in seawater intrusion forecasting, if possible.     

基于“三条红线”的海水入侵区地下水保护体系

随着沿海经济的快速发展,当地对淡水资源、特别是地下淡水的开发利用强度不断加大,地下水超采日益严峻,地面沉降、海水入侵等环境地质灾害频繁发生。现以烟台市区为例,应用最严格水资源管理制度指导思想,以"三条红线"为约束,通过实施多水源联合调度,提出了海水入侵区地下水调控方案和保护对策,在此基础上构建海水入侵区地下水保护体系,用以科学指导地下水开发、利用、保护和管理实际工作。     

洪水过程对河岸带地下水水位波动的影响

为揭示洪水作用下河岸带地下水的响应过程,利用室内物理模型试验和数值模拟,研究了不同洪峰及洪峰持续时间对地下水水位波动的影响。结果表明:河岸带地下水水位的波动具有不对称性,水位上升快下降慢,沿程地下水水位的波动呈指数形式衰减,并表现出明显的滞后性;随着洪水洪峰增大,地下水水位波动增大,河水和地下水的交换量增大,而地下水水位的滞后变化不明显;洪峰持续时间变长,地下水水位的滞后性显著,内陆地下水水位波动的幅度增大,恢复至初始状态的时间变长。     

滨海地区海水入侵的一种测定方法

海水由于含盐量较高而具有较高的电导率,通过测定滨海地区的地下水电导率并和该地区地下水标准电导率进行对比,可判断海水入侵现象。结合辽宁省大连市一处海边场地,介绍了根据地下水中的电导率分布情况来判断场区是否存在海水入侵的方法:通过对现有观测孔的电导率测试,选择适当的剖面,绘制各剖面的电导率分布图,结合当地的水文地质情况,判断是否有海水入侵现象以及海水入侵的范围和程度。测试结果表明,场区除局部电导率偏高外,没有发生大面积的海水入侵现象。     

陆源淡水流量对海岸水库海水入侵的影响

采用平板水槽系统开展了室内物理模型试验,探究了陆源地下水流量与入库地表水流量对海岸水库海水入侵的影响。结果表明:海岸水库的下盐水楔入侵长度与陆源淡水流量呈对数下降关系,随着陆源淡水流量的增大,下盐水楔入侵长度减小趋势减弱;与陆源地下水相比,入库地表水对海岸水库海水入侵的抑制作用更显著;随着陆源淡水流量增大,海岸水库库底盐分减少,上盐水楔比下盐水楔先减小、消失;通过减少地下水的开采和采取调水入库的手段可以抑制海岸水库海水入侵,缓解水库水体的咸化。     

SWOT analysis in groundwater resources management of coastal aquifers: a case study from Greece

This paper applies a SWOT (strengths, weaknesses, opportunities and threats) analysis to groundwater resources management of a coastal aquifer in northern Greece typical of those subjected to seawater intrusion. SWOT analysis is found to be a useful managerial tool, incorporating interdisciplinary issues – engineering, scientific, legislative, economic and social – which are difficult to quantify, in order to identify the main environmental problem of the study area, which is overexploitation of the groundwater resources (and seawater intrusion as a consequence). Based on the main outcomes of the SWOT model, specific countermeasures are suggested in order to combat the over-pumping of the aquifer's resources which leads to overexploitation of the groundwater potential.     

砂—粘土中海水入侵规律试验与数值模拟

近年来我国沿海城市海水入侵现象越来越严重,为了防治海水入侵,对其入侵规律的研究非常必要。本文通过室内试验与Geostudio数值模拟研究给出了砂—粘土介质中海水入侵的规律。结果表明,不同土体的海水入侵规律不尽相同;同种土体不同位置的入侵规律也不同;两种接触面上的入侵规律同时受两种介质影响,其入侵规律同时受土体颗粒大小、渗透系数、试验材料等因素影响。本研究对福建泉州地区海水入侵的研究有较大的参考价值。