厦门湾砂质潮间带海底地下水排泄的非均质性研究

以厦门岛南岸砂质海岸为研究对象,通过监测潮间带渗出面处地下水盐度、近岸海水盐度,并分析潮间带盐度空间分布规律,以探究厦门湾海底地下水排泄(SGD)的非均质性。结果显示:1)潮间带地下水、海水盐度变化可以间接指示海底地下淡水排泄量(SFGD)。2)垂直于海岸线方向,由内陆向海洋地下水盐度呈现先降低后升高的规律;沿海岸线方向,整个潮滩地下水盐度分布不均匀,差异性较大,具有明显的非均质性。3)通过对潮间带中部最低盐度区域进行加密监测,圈定了厦门湾潮间带高渗透天窗范围,推测高渗透天窗对SFGD影响较大。4)通过对典型剖面地下水、近岸海水盐度动态监测,发现潮汐对潮间带SFGD产生一定影响。

马克思生产劳动范畴的理论意蕴及当代启示

科学建构中国生产劳动范畴,有利于激发各类劳动者创造财富的积极性,为中国式现代化增进思想共识、凝聚实践合力。基于对马克思生产劳动理论的文本发掘和系统研究,凝练了生产劳动范畴内在的物质规定性、形式规定性、价值规定性,论证了三重规定性的辩证统一、物质规定性的本源意义,探索并解析了社会发展中的时间结构转换规律。遵循马克思生产劳动概念的生成逻辑,建构了内含三重规定性的中国生产劳动范畴,即:创造满足人民美好生活需要的物质生产领域的劳动,其新创造的价值不少于劳动者的生活消费品的价值。中国生产劳动范畴体现了社会主义本质要求、契合中国式现代化的特征。对此,提出要正确认识各类劳动的属性和功能,促进各类劳动的合理有效配置,加强实体经济领域的劳动就业,引导非生产劳动资源更多投向科学、教育、医疗、文化、艺术等促进人的现代化的领域。

不同网格加密方法在河流回补地下水模拟中的对比

河流回补地下水是线状回补过程,河道附近地下水位高精度模拟是回补效果准确评估的关键。基于非结构化网格加密方法,设定4种不同的网格剖分方案(两种结构化网格和两种局部加密的非结构化网格),在不同边界条件下对河流回补地下水过程进行模拟。通过对末流场、距离河道不同范围回补前后水位变差、地下水均衡和模型运行效率的对比分析,阐明线状回补模拟中不同网格加密方法的优劣。结果表明:与粗结构网格模型相比,两种局部加密的非结构化网格模型以及细结构网格模型的模拟精度高,能更准确刻画因河道回补导致的地下水位变化;两种局部加密的非结构化网格模型比细结构网格模型运行时间短,在没有大幅降低模拟精度的条件下,运行效率更高;四叉树网格模型相对于嵌套网格模型具有长期模拟的优势,在河流回补期末,模拟精度要稍高于嵌套网格模型;同时,四叉树网格模型具有多级加密的优势,加密级次越多,剖分的网格数量相对越少,运行时间相对更短。综上所述,四叉树网格加密方法既保证了模拟精度,又一定程度上提高了模型运行效率,是值得推广的一种局部网格加密方法。

Development of a new method for efficiently calculating of evaporation from the phreatic aquifer in variably saturated flow modeling

In this paper, we proposed a new method that has been developed based on the surface soil moisture content(SSMC) to more efficiently calculate the groundwater evaporation in variably saturated flow modeling. In this method, the empirical formula to calculate evaporation was modified and the value of the formula varies from zero to one as a closed interval. In addition, the simulation code for calculating the groundwater evaporation based on the SSMC method was incorporated into the EOS9 module of Tough2, a variably saturated flow modeling code. Finally, two numerical tests and a case simulation were conducted to verify the feasibility and accuracy of the SSMC method. Simulation results indicate that the SSMC method is capable of appropriately simulating the characteristics of water flow in vadose zone and the amount of evaporation with the variable water table. And such results are in coincidence with the value calculated by the logistic function method, and fit well with the measured data globally rather than locally.

Assessment of shallow groundwater vulnerability in Dahei River Plain based on AHP and DRASTIC

Based on the special hydrogeological conditions of the Dahei River Plain in the Inner Mongolia area, assessment of shallow groundwater vulnerability is conducted based on DRASTIC model. Each evaluation indicator weight is determined by using analytic hierarchy process(AHP). The most important indicators are lithology in soil media and vadose zone. Assessment model of shallow groundwater vulnerability of the Dahei River plain is constructed. Distribution map of vulnerability index in this area is made with the spatial analysis function of ARCGIS. The results show that the particularly sensitive area is the piedmont of the Daqing Mountain, where the upstream place of the groundwater and the south-central place of the plain has the lowest vulnerability. The assessment results are more in accordance with the actual vulnerability conditions of this area by using analytic hierarchy process, and is helpful for groundwater protection.

Numerical simulation of response of groundwater flow system in inland basin to density changes

The developmental characteristics of groundwater flow system are not only controlled by formation lithology and groundwater recharge conditions,but also influenced by the physical properties of fluids.Numerical simulation is an effective way to study groundwater flow system.In this paper,the ideal model is generalized according to the fundamental characteristics of groundwater system in inland basins of Western China.The simulation method of variable density flow on the development of groundwater system in inland basins is established by using EOS9 module in TOUGHREACT numerical simulation software.In accordance with the groundwater streamline,the groundwater flow system is divided into three levels,which are regional groundwater flow system,intermediate groundwater flow system and local groundwater flow system.Based on the calculation of the renewal rate of groundwater,the analysis shows that the increase of fluid density in the central part of the basin will restrain the development of regional groundwater flow system,resulting in a decrease of the circulation rate from 32.28% to 17.62% and a certain enhancement to the local groundwater flow system,which increased from 37.29% to 51.94%.

The drainage of the aquitard and its implication for groundwater exploitation in Hengshui City

The deformation and the drainage of the aquitard is the main concern in the North China Plain(NCP), and the water released from aquitard compaction may be a large portion of the exploited groundwater. The skeletal specific storage of aquitard is the element parameter to the drainage of aquitard, and the undisturbed core samples are the best choice for the measurement of the physical parameters. In this study, the consolidation test was employed to analyze the skeleton specific storage of the clay sample drilled from Hengshui City, and the contribution from the drainage of aquitard to the groundwater exploitation. The results suggest the consolidation test can be utilized to understand the skeletal specific storage of aquitard, which is about 3.92×10-4 m-1 in the Hengshui. The water-saturation content of the aquitard was less than 100%, and the amount of the drainage of the aquitard was about 69% of the volume of land subsidence. The water released from aquitard compaction was about 35% of the groundwater exploitation to the deep aquifers.