山东福山铜矿岩溶裂隙水充水矿井涌水量预测

福山铜矿位于山东省烟台市,围岩主要是大理岩,岩溶裂隙水为矿床直接充水水源。在分析研究区水文地质条件、岩溶发育特征和地下水流态的基础上,建立了地下水三维渗流模型,模型考虑了地下水在三个主渗流方向上的各向异性,将疏干巷道概化为排水沟,针对金属矿床开采水位降深大,边界流量随着降深的增大而增加,采用通用水头边界,随着降深的变化边界流入量依据水位值计算得到。利用群孔抽水试验资料和长期观测资料对模型进行识别和验证,最终对矿井疏干排水量和不同年份的正常涌水量进行预报,模拟结果为-80 m、-200 m、-300 m、-400 m和-450 m水平平水年正常涌水量分别为7 500 m3/d、14 060 m3/d、28 070 m3/d、37 200 m3/d和41 600 m3/d。从岩溶发育特征和地下水流动特征看,在这类岩溶地区建立地下水三维渗流模型是可行的。      

屋顶雨水回灌裂隙岩溶含水层连通示踪试验

雨水回灌后对岩溶水的影响分析和效果需要对回灌井和下游的观测井监测数据说明。由于岩溶含水层中岩溶发育极不均匀,在测定地下水位并判定出地下水流向的基础上,连通示踪试验是选择与回灌井相对应的观测井的有效办法。用氯化钠作为示踪剂,监测不同测井不同埋深地下水电导率随时间变化的方法确定了岩溶水观测井选址、岩溶含水层的结构及水文地质条件。示踪试验结果表明,3#观测井(西院井)可用来监测雨水回灌效果,并计算出该地区的地下水势流速在9 m/h～20 m/h之间。该成果对北方地区岩溶含水层回灌和环境评价具有重要的参考价值。     

广西黎塘岩溶塌陷监测

黎塘是一个构造和岩溶发育的地区,抵抗岩溶地面塌陷的能力较低,在一定的条件触发下较容易产生岩溶地面塌陷。研究表明,岩溶地下水动力条件变化和湿化崩解作用是黎塘塌陷的主要影响和触发因素。本文采用现场实时监测岩溶地下水动态变化特征和室内试验相结合的方法,研究黎塘开发岩溶地下水的安全性。监测结果表明, I、II、II I监测区的最大水压变化速度分别为0. 048kPa /s、0. 160kPa /s和0. 007k Pa /s,小于临界变化速度0. 163kPa /s;最大水力坡降分别为0. 717、1. 052和0. 566,小于临界坡降7. 5。但是, I区满足临界水位埋深条件, 而II区和II I区则未满足临界水位埋深条件。因此,在目前的开采条件下, II 区、III区处于相对稳定状态, I区处于不稳定状态。这说明在发生大规模塌陷后,当地政府从2000年起对地下水开发方案的调整是适当的。      

滦县新建地下水源地开采方案论证

合理的水源地开采方案对地下水资源可持续利用,避免影响周边水资源和地质环境,均有重要的意义。以滦县新建傍河地下水水源地为研究对象,在明确研究区域水文地质参数的基础上,对水源地开采方案即水源井数量、布置方式、水源地中心点位降深、允许开采量及对周边环境地质的影响进行论证。开采方案确定为靠近滦河布置两排共12眼水源井,开采水量4×10⁴ m³/d。结果显示,连续开采30 a中心点水位降深为7.35 m,开采条件下对滦河的激发补给量会有所增加,水源地开采4×10⁴ m³/d地下水是有充分保证的,地下水仍保持采补平衡略有盈余的状态,且对周边的地质环境不会产生不利影响。     

西南岩溶地下水资源开发利用效应与潜力分析

西南岩溶地区面积78万km2,地下水系统包括裸露岩溶水系统和覆盖-埋藏型岩溶水系统两大类。由于降水丰富、地下岩溶发育,西南岩溶地下水资源丰富,在43万km2调查区内,具有地下水天然资源量1762.82×108m3/a,岩溶地下水允许开采资源量615.70×108m3/a。近年来,通过开展水文地质调查,在地下河、表层岩溶水和蓄水构造岩溶水打井开采方面均取得重要进展,产生了显著的经济和生态环境效应。但由于西南地区岩溶水开发难度大,区域经济落后,西南岩溶地下水的开发利用程度普遍较低,已开采量为98.32×108m3/a,仅占允许开采量的15.97%,剩余地下水潜力资源量517.38×108m3/a。     

北京西山岩溶水应急水源地水文地质特征及开采潜力分析

应急水源地位于北京西山四季青地区,取水层位为奥陶系含水层,属覆盖型水源地。奥陶系岩溶地下水水量大、水质优良,是保障北京供水安全的后备水源。本文在综合分析奥陶系岩溶地下水水文地质特征基础上,以群孔抽水试验为基础,采用相关分析法预测水位,从岩溶地下水的富水性、地下水流场、地下水资源方面分析岩溶水的开采潜力,确保在出现水源危机时,岩溶地下水能够作为后备水源地为城市供水。结果表明,岩溶地下水应急水源地岩溶裂隙发育,补给条件好,地下水径流强度大,水质优良,具有6万m3/d的开采潜力,即当水源地增加每日6万m3应急开采时,水位埋深预测值为52.94m,能够满足现有取水设备条件,且不会影响其它水源井的运行。      

山西岩溶水强径流带的成因类型及其水文地质特征

根据成因特征,将山西岩溶水强径流带分为五种类型: 接触带型、河谷型、构造带型、向斜谷地型和复合型。通过野外调查及对大量实测资料的分析研究,揭示出山西岩溶水强径流带的主要发育与分布特征: 岩溶水强径流带呈网状分布;发育深度50～300m;地下水面呈槽谷型,水力坡度一般在0. 6‰～2. 8‰之间。岩溶强径流带水量丰富,单井出水量大于1000m3 /d,是建立岩溶水水源地的理想场所。      

论"单位涌水量就是导水系数"

单位涌水量是井抽水水位降深换算为1 m时的单井出水量;导水系数是含水层宽度为1 m时,地下水水力坡度为1时的单宽流量.二者之间从定义上看毫无关系,但它们的单位(m3/d·m)(m2/d)是相同的.笔者经过多年探讨和初步试验后发现,单位涌水量就是管井抽水所利用含水层的导水系数.     

赣南青塘盆地岩溶水特征及开发利用区划

通过地面调查、地球物理勘探、水文地质钻探及采样测试等手段,研究赣南青塘盆地岩溶水特征。研究表明,盆地内岩溶水主要赋存于岩溶地下河及岩溶管道-裂隙含水层中,水资源较为丰富,局部以地下河及岩溶上升泉形式溢出地表,地下水开发以地下河及岩溶上升泉为主。综合分析认为：青塘岩溶盆地内岩溶分布在侵蚀基准面以上,沿层面发育并受断裂及构造裂隙控制;水化学类型以HCO₃-Ca型、HCO₃·SO₄-Ca型为主,分别占总水样的58.33%、20.83%;地下水水质以较好(Ⅲ类)为主,占盆地内总水样的50.00%;青塘岩溶盆地外来地表水汇入流量为117 094.5 m³/d,汇出流量为416 007.8 m³/d,内部基础径流量为298 913.3 m³/d。在综合分析盆地内岩溶地下水和地表水富集程度、地下水开发条件和环境承载力等因素基础上,结合地貌和流域特点、盆地内岩溶塌陷易发性分区,对区内岩溶地下水资源开发利用进行了区划,为该区合理利用岩溶水资源提供依据。     

滇东断陷盆地南洞岩溶地下水系统地下河水文动态特征与资源量评价

本文对滇东断陷盆地南洞岩溶地下水系统各地下河的水文动态特征进行了分析,推断了南洞岩溶地下水系统的结构特征.根据岩性构造、地下河发育以及补径排关系,将其划分为四个子系统.分别采用降雨入渗系数法和径流模数法对南洞岩溶地下水系统的天然资源量进行计算,计算结果分别为35610.7万m3/a和33460.2万m3/a.用枯季径流...     

沈阳市阳光港湾建筑群基坑降水施工研究

沈阳市阳光港湾建筑群高层建筑采用筏板基础,多层建筑采用人工挖孔灌注桩基础,在基础施工时,均需进行相应的降水工作。采用了分期降水的施工方法,首期降水施工是在分析场地水文地质条件的基础上,利用稳定流"大井法"预算基坑的涌水量,布置了9口井,使基坑周边的1#、2#、3#、4#观测孔水位均下降至5.11m,基本上达到了首期的降水的目的;第二期降水是利用首期降水观测的水位资料,采用稳定流干扰井群计算公式对场区地下水位进行了预报,重新设计了3口井。12口井全部投放使用后,测得稳定排水量为43 000m3/d,并形成了以基坑为中心的地下水降落漏斗,降水效果明显。此经验值得同类工程借鉴。     

地下水与地表水水量交换识别及交换量计算——以新汴河宿州段为例

为提高地下水与地表水交换量计算结果的准确性,本文利用水力联系、水头差、水温、氡-222、氢氧稳定同位素构建综合识别方法(HHTRO),对新汴河宿州段地下水与地表水水量交换进行识别,并计算交换量。计算结果表明：研究河段单位河长地表水补给地下水的水量变化范围为8.69～366.82 m³/(d·m),地下水补给地表水的水量变化范围为0.72～120.90 m³/(d·m);研究河段左岸为地下水补给地表水,单位河长净补给量为45.26 m³/(d·m);河段右岸为地表水补给地下水,单位河长净补给量为214.33 m³/(d·m);研究河段地下水与地表水水量交换以地表水补给地下水为主,地表水补给地下水的比例为55.14%。本研究可推动地下水与地表水交换量计算方法的发展,为流域或区域水资源评价提供必要的理论方法。     

Effect of Excavation-Induced Groundwater Level Drawdown on Tunnel Inflow in a Jointed Rock Mass

Analytical and empirical methods used in current engineering practice for estimating inflow rate into a tunnel do not adequately account for the effect of groundwater level drawdown which triggers changes of the flow pattern as well as reductions of the hydraulic head. When there is no reservoir or a large body of water near the tunnel alignment, the groundwater recharge above the tunnel might not be fast enough to avoid a significant excavation-induced water level drawdown. This paper provides analytical methods for estimating groundwater inflow rate taking into account the groundwater table drawdown. The proposed analytical solutions presented here compare well with field observations as well as with results from numerical analysis using distinct element method which can adequately simulate the hydro-mechanically coupled behavior of joints in a rock mass.     

Modeling of groundwater flow for Mujib aquifer, Jordan

Jordan is an arid country with very limited water resources. Groundwater is the main source for its water supply. Mujib aquifer is located in the central part of Jordan and is a major source of drinking water for Amman, Madaba and Karak cities. High abstraction rates from Mujib aquifer during the previous years lead to a major decline in water levels and deterioration in groundwater quality. Therefore, proper groundwater management of Mujib aquifer is necessary; and groundwater flow modeling is essential for proper management. For this purpose, Modflow was used to build a groundwater flow model to simulate the behavior of the flow system under different stresses. The model was calibrated for steady state condition by matching observed and simulated initial head counter lines. Drawdown data for the period 1985–1995 were used to calibrate the transient model by matching simulated drawdown with the observed one. Then, the transient model was validated by using drawdown data for the period 1996–2002. The results of the calibrated model showed that the horizontal hydraulic conductivity of the B2/A7 aquifer ranges between 0.001 and 40m/d. Calibrated specific yield ranges from 0.0001 to 0.15. The water balance for the steady state condition of Mujib aquifer indicated that the total annual direct recharge is 20.4 × 10⁶m³, the total annual inflow is 13.0 × 10⁶ m³, springs discharge is 15.3 × 10⁶ m³, and total annual outflow is 18.7 × 10⁶ m³. Different scenarios were considered to predict aquifer system response under different conditions. The results of the sensitivity analysis show that the model is highly sensitive to horizontal hydraulic conductivity and anisotropy and with lower level to the recharge rates. Also the model is sensitive to specific yield     

井周流场,水跃值与井内水位降深的关系

本文以单井稳定流抽水为例，从井固流场与地下水向集水井幅射流的涌水量方程入手，阐明井结构，井周泥浆堵塞和井内水位降深的关系。证明了水跃值是井周泥浆堵塞降深与井周三维流域或紊流引起的二次项降深（简称“井损“）之代数和，并得出了水跃值不同组成部分随井内降深变化而变化的规律。从而提出了消除水跃值，利用裘布依涌水量方程进行水文地质参数计算。     

Simulation of horizontal well performance using Visual MODFLOW

A proposed horizontal well or radial collector well installation in shallow aquifers to enhance water withdrawal rates in Pintu Geng well field in Kelantan, Malaysia was simulated using the Drainage Package of MODFLOW groundwater model. The modelling exercise aimed at identifying an optimum pumping rate that would safely achieve the desired drawdown of less than 2 m in an area of 300 m radius surrounding the Pintu Geng horizontal collector well. The model also would serve as a basis for the design of the horizontal well components. High degree of grid refinement for the well location is needed to simulate the real field installation. However, for the purpose of designing water withdrawal systems, it is important to obtain the correct production rate of these wells for a given drawdown. A transient groundwater flow model was calibrated and validated with few assumptions of the horizontal well hydraulic properties. The model demonstrates that under natural flow condition at ?3 m depth, the six collectors (drains) tap a volume of 19,200–43,700 m³/day. A steady-state model was also developed to predict the capture zone delineation. Attention is also given to the impact of the well installation to the surrounding 300 m radius by inspecting the degree of the drawdown.     

鄂尔多斯盆地地下水勘查

鄂尔多斯盆地矿产资源丰富，生态环境脆弱，地下水资源分布不均，水质复杂。在研究盆地周边岩溶区岩溶发育规律，地下水富集规律，地下水的补给、径流、排泄条件的基础上，将周边岩溶区划分为9个岩溶水系统，进一步划分为25个岩溶水子系统。白垩系自流盆地初步揭示了深部赋存有丰富的地下水，地下水受岩相古地理、地下水补径排条件等控制，水质差异较大。总结了东部黄土覆盖区的地下水类型及开发利用模式。     

Numerical Simulation of Groundwater Flow and Vulnerability in Wadi El-Natrun Depression and Vicinities,West Nile Delta,Egypt

During the last 25 years, rapid and unplanned land reclamation activity has been carried out in the areas located in both south and east of Wadi El - Natrun Depression of Egypt. Accordingly, negative effects on groundwater levels and vulnerability are frequently caused by localized high levels of abstraction and the return-flow of polluted irrigation water respectively. A groundwater model is a computational method that presents an approximation of an underground water system. In this study the groundwater system is simulated both in quantity and quality by using Mass Balance Transfer Model (NETPATH), Groundwater Modeling System (GMS) and DRASTIC Model to investigate the water - rock interactions, groundwater levels drawdown and vulnerability respectively. Three main geochemical processes namely dedolomitisation, dissolution of halite and silicate weathering were estimated during the flow path. The present over-abstraction of groundwater (105.84 million m³/year) has induced a general head drawdown from 3 to 40 m in years 2015 and 2050 respectively. Best estimate using a 3D GMS hydraulic model was (157000 m³/day) a strategy proposed for the management of groundwater without critical depletion (second scenario). The results document the extent to which a high drawdown can greatly reach 4 m by the end of simulation year 2050. The vulnerability maps of groundwater were constructed using the DRASTIC index method. The results indicated that, the southeastern and central portions of the study area are having high vulnerability rate (> 110). Modified DRASTIC map showed many more dominant high risk areas in the eastern parts of the study area that were low risk, which may be attributed to return flow of polluted irrigation water.     

The dependence of stream depletion by seasonal pumping on various hydraulic characteristics and engineering factors

Compensation pumping is used to alleviate deficiencies in streamflow discharge during dry seasons. Short-term groundwater pumping can use aquifer storage instead of catchment-zone water until the drawdown reaches the edge of the stream. The capacitance is a complex, dimensionless parameter of an aquifer system that defines the delayed effect on streamflow when there is groundwater pumping. This parameter is a function of aquifer hydraulic characteristics, pumping time, and distance between the well and stream edge; the latter can involve stream leakance and vertical leakance of an associated aquitard. Three typical hydraulic cases of combined water systems (major catchment-zone wells close to the stream and compensation pumping wells) were classified depending on their capacitance structure (i.e. the relationship between surface water and groundwater): (1) perfect hydraulic connection between the stream and aquifer; (2) imperfect hydraulic connection between the stream and aquifer; and (3) essentially imperfect hydraulic connection between the stream and the underlying confined aquifer. The impact of various hydraulic characteristics and engineering factors on stream depletion was examined by conceptual and numerical modeling. To predict the suitability and efficiency of a combined water system application, regression tests were undertaken on unit stream depletion and capacitance, and power dependencies were defined.