基岩岛屿地下水流场数值模拟研究

Research on the numerical simulation of the groundwater flow field in bedrock islands

岛屿是我国领土的重要组成部分,对国家安全和国防军事意义非凡。岛屿的地下水资源尤为珍贵,地下水流场模拟是研究地下水分布规律的重要手段。水文地质条件复杂、可利用的观测井较少等原因,造成了基岩岛屿水文地质模型概化精度不高、初始条件难以获取等问题。为克服基岩岛屿地下水流场模拟的诸多困难,将珠海外伶仃岛作为研究区,利用数字高程模型数据开展地质地貌建模;利用探地雷达法、直流电法与地质分析对岛屿进行探测,获取了地层数据;采用地下水遥感评估法,利用实测井位数据,确定了地下水的初始水位,进而对基岩岛屿地下水流场进行建模;最终,通过对外伶仃岛地下水流场的数值模拟得出地下水模拟流场图。岛上多个测点的探测水位值与模拟水位相关性较好,其拟合优度R 2为0.8722。由此可见,综合遥感、物探、水文地质手段等技术方法获取的数据,采用地下水模拟软件或程序实现基岩岛屿地下水流场的数值模拟,是基岩岛屿地下水资源研究的一个有效方法。

The island is an important part of our territory,and it is of great significance to our national security and national defense.Groundwater resources in islands are particularly valuable.Simulation of the groundwater flow field is an important method to study the distribution of groundwater.Due to the flexible hydrogeological condition of islands and a small number of observation wells,the accuracy of hydrogeological model generalization was not high and the initial conditions were difficult to obtain.In order to overcome these difficulties of the groundwater flow field simulation in bedrock islands,the authors chose Wailingding Island in Zhuhai as a study case to build the geological model of island using the digital elevation model data.The geological layers data of the island were acquired thraugh GPR method,DC method and hydrogeological means.The initial water level of the groundwater was determined to build the groundwater flow field model by remote sensing elevation and well data.Finally,the groundwater flow images of simulation results were mapped through the numerical simulation of groundwater flow of Wailingding Island.The actual water levels of the measured multiple points were well correlated with the simulated water levels,with R 2 of 0.8722.It can be seen that using integrated remote sensing,geophysical prospecting,hydrogeological means and other methods and technologies to obtain data,and using the methods of simulation softwares or programs to simulate data,were effective research methods in the field of island groundwater resource.