基岩岛屿地下水数值模拟发展研究现状

基岩岛屿占我国岛屿的90%以上,且岛屿上的淡水资源十分珍贵。目前,岛屿上的供水(船运、雨水收集、海水淡化等)存在成本高、设备易坏等缺点。因此,岛屿的地下水资源无疑是优质、可靠、稳定的供水源。为了更好地开发基岩岛屿地下水资源,认为针对基岩岛屿地下水模拟,从地下水理论、地下水模拟的国内外研究现状和模拟模型等方面进行了综述。总结认为: 基岩岛屿的地下水多以“淡水蘑菇体”的形式储存,有别于沙质岛屿; 模拟模型应概化为横向各项同性的达西流或非达西流,或二者的耦合模型,并归纳了相应的地下水流运动方程; 基岩岛屿地下水模拟模型应分为孔隙型、裂隙型和孔隙-裂隙型3种类型; 在岛屿边界设定上,基岩海岸应设为隔水边界,沙质海岸应设为定水头边界。综述研究认为: 基岩岛屿地下水模拟模型应尽可能精细、完整、精准地刻画基岩岛屿的地质地貌,设置完整的岛屿补径排项; 模拟时,应准确对应基岩岛屿的地下水类型,选准模拟方法与模拟软件; 模型验证工作也是十分重要,需多次与岛屿水量均衡,且与实测水量和水位作对照,不断地修善模型。以上综述成果为我国今后开展基岩岛屿地下水数据模拟提供了理论依据。

Development and research status of numerical simulation on the groundwater of bedrock islands

Bedrock islands account for more than 90% of China’s islands, and the fresh water resources on the islands are very precious. Currently, the islands’ water supply (shipping, rainwater collection, seawater desalination, etc.) has disadvantages of high costs and the equipment on the islands damages easily. Therefore, the islands’ groundwater resources are undoubtedly high-quality, reliable and stable water supply. In order to better develop the groundwater resources of bedrock islands, the authors reviewed the groundwater simulation of bedrock islands from the aspects of groundwater theory, groundwater simulation research status at home and abroad, simulation model and so on. It was concluded that the groundwater in bedrock islands is mostly stored in the form of “fresh water mushroom body”, which is different from sandy islands. The simulation model should be generalized as transverse isotropic darcy flow or non-darcy flow, or a coupling model of these two models, and its corresponding motion equation of groundwater flow was concluded. The groundwater simulation model of bedrock islands can be divided into three types: pore type, fissure type and pore-fissure type. In the setting of island boundary, bedrock coast should be set as confining boundary and sandy coast as constant head boundary. This review shows that researches on groundwater simulation of bedrock islands should be as refined and complete as possible, to accurately depict the geology and landform of bedrock islands and set a complete complement for island drainage. During the simulation, the groundwater types of bedrock islands should be exactly matched with the simulation methods and software. Model verification is also very important, which needs to be compared with island water balance, measured water amount and water level for many times, and the model needs to be improved constantly. The above achievements could provide theoretical basis for the groundwater numerical simulation of bedrock islands.