Forecasting of Hydrographs to Simulate Long Term Recharge From Rivers in Numerical Models of Mining Reservoirs; Application to A Coal Mine in NW Spain

Although the natural permeability of rocks in the Asturian Central Coal Basin (NW Spain) is generally low, intensive mining activities over many decades has given rise to fracture flow paths that are far more permeable than those associated with the natural lithology. Abandoned and flooded mining works set up artificial ‘pseudo‐karst’ aquifers, which can act as underground reservoirs, with many potential applications. In particular, a mining reservoir shaped by two connected mining shafts within the River Turón basin has been studied. A runoff model was used to produce accurate simulations of streamflow in three different gauging stations during a monitored period of 2 years. The purpose was to use this model in the forecast situation, in order to predict long‐term situations in a hydrogeological FEFLOW model. It was necessary to develop depletion curves for each gauging station based on the available daily effective rainfall and measured flow data, as well as the knowledge of the basin characteristics. The resulting simulated hydrographs were very similar to the measured hydrographs during the monitored period, so the adequate adjusting allows input of the flow for forecast purposes. The model produced forecast hydrographs that had a r = 0.8 and difference in annual volume ranging from 1.6% to 5%. The defined model was applied to a rainfall data set of 30 years, and the average recharge from the river to the mining reservoir could be adequately estimated. The method developed needs to be refined and tested on additional years, but the approach appears to be applicable to operational runoff forecasting for numerical models input data. Copyright © 2015 John Wiley & Sons, Ltd.     

Finite element modeling of borehole heat exchanger systems: Part 2. Numerical simulation

Single borehole heat exchanger (BHE) and arrays of BHE are modeled by using the finite element method. Applying BHE in regional discretizations optimal conditions of mesh spacing around singular BHE nodes are derived. Optimal meshes have shown superior to such discretizations which are either too fine or too coarse. The numerical methods are benchmarked against analytical and numerical reference solutions. Practical application to a borehole thermal energy store (BTES) consisting of 80 BHE is given for the real-site BTES Crailsheim, Germany. The simulations are controlled by the specifically developed FEFLOW-TRNSYS coupling module. Scenarios indicate the effect of the groundwater flow regime on efficiency and reliability of the subsurface heat storage system.     

基于FEFLOW的油库污染物渗漏模拟研究

针对油库正常运行中可能出现的渗漏污染问题,以云南省某地下油库为研究对象,利用FE-FLOW软件,采用数值分析方法,对研究区内典型污染物在不同工况下的污染物迁移进行模拟.计算结果表明,在正常工况下,污染物的影响范围随时间增加而增大,但是影响范围未超出厂区,不会对周边环境造成污染;在油库防渗层失效的非正常工况下,污染物的扩...     

复杂断层矿区地下水三维数值模拟

为了提高复杂断层矿区地下水数值模拟结果的准确度,以内蒙古某矿区错综分布的10条倾斜断层为研究对象,采用FEFLOW软件将倾斜断层简化处理为垂直透水断层,建立复杂断层矿区地下水三维数值模型,并预测了矿区开采30年后对上覆各含水层的破坏程度。结果表明:二叠系山西组砂岩裂隙含水层受开采直接影响,最大降深约150.23 m;上覆二叠系石盒子组砂岩裂隙含水层和新近系砂砾石含水层无稳定隔水层,水位差的加剧导致越流量增加,最大降深约23 m;第四系松散孔隙含水层由于下部完整且较厚的黏土层,基本上不受影响。对断层的有效概化有助于提高数值模型的仿真性和结果的精准度。     

衡水市地下水流数值模拟

通过对衡水市地下水系统特征的分析,建立了水文地质概念模型,并用FEFLOW建立三维地下水流数值模拟模型。应用识别与校正后的模型预测不同开采方案下的地下水动态。对于浅层地下水,方案1水位下降速率最慢,方案4水位下降速率最快;对于深层地下水,方案2水位最高,下降速率最慢,方案3水位最低,下降速率最快。从地下水资源可持续利用角度考虑,按方案2规划开采比较合理。     

基于FEFLOW的地下水环境影响评价研究

运用FEFLOW有限元地下水模拟软件,对某条件下地下水环境进行了评价研究。根据水文地质条件、地质条件,建立了数学模型以及水文地质概念模型,利用FEFLOW数值模拟软件研究了地下水流场、分层的均衡性、潜水埋深、潜水水位,研究得出:在矿井开采与某水源开采的条件下,形成了以某水源地为中心的大范围降落漏斗,从而造成潜水位下降程度相近;矿井抽水造成的潜水位下降和水源地抽水影响相比并不明显;2种方式的开采造成潜水埋深大幅度增加,导致了评价区域内潜水获得的蒸发量和大气降水入渗补给量明显降低,研究为类似工程条件下地下水环境影响评价提供一定的借鉴意义。     

封闭式路堑U型槽结构抗浮设计水位计算方法探讨

封闭式路堑U型槽结构作为纯地下建筑,抗浮问题非常突出。本文以北京某封闭式路堑U型槽结构工程为例,在对场区进行水文地质条件分析及远期最高水位预测的基础上,建立适用的水文地质概念模型及地下水流定解数学模型,使用FEFLOW软件建立了场区三维数值模拟模型,利用该模型进行抗浮设计水位预测。模型建立过程中考虑了场区各含水层的非均质性及场区潜水最高水位接近自然地面的工程特点。     

Open-loop groundwater heat pumps development for large buildings: A case study

A study of the feasibility of providing the heating and cooling needs of the new, large commercial building near Turin, Italy, by means of an open-loop indirect groundwater heat pump (GWHP) system is described. A finite element subsurface flow and transport simulator (FEFLOW) was used to investigate possible configurations of extraction and injection wells for five different scenarios. Modelling results confirmed the hydrogeological capacity of the site to provide the necessary amount of groundwater and associated energy with limited environmental impact. Injection of warmer (or cooler) water in the aquifer creates a thermal plume whose dimensions and geometry depend on the properties of the subsurface formations, particularly their thermal dispersivity values. The study suggests that there are several possible well configurations that could support the GWHP system without adversely affecting the aquifer.     

不同土地利用模式下绿洲地下水响应预测模拟

将GIS与专业计算地下水运动的FEFLOW模型结合,建立地下水模型预测不同土地利用模式对干旱区绿洲地下水资源的时空分布产生的影响。研究区域选取三工河流域绿洲区,模型模拟显示绿洲上部主要城镇聚居区地下水位逐渐下降,下部地下水位呈现缓慢上升趋势。耕地作为显著变化的土地利用类型,成为影响区域地下水资源的决定性因素。     

郑州北郊水源地地下水位预测

应用FEFLOW软件，对郑州北郊水源地建立三维地下水流方程求解，并对模型进行识别和检验。对水源地水位进行了预测。预测结果与实测水位对比表明：模拟潜水流场与实际流场总体流动方向相同，大部分结点水位拟合较好，模型精度能够满足要求。