科尔沁典型沙丘一草甸相间地区地下水位对降雨的响应及地下水流数值模拟研究

发布时间：2018-03-17 01:29

本文选题：科尔沁沙地　切入点：地下水数值模拟　出处：《内蒙古农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文通过对科尔沁沙地典型沙丘一草甸相间地区天然降雨和地下水位数据的联合观测,研究了科尔沁沙地不同地貌类型下地下水位对不同降雨量级的响应关系和地下水位动态特征,并以此为降雨入渗补给系数的调参依据,结合地质钻孔、物探和前人的数据资料,利用GMS软件建立了地下水流三维数值模拟模型。取得的主要成果有：1)受地下水位埋深、植被类型、土壤物理性质和地下水径流-补给条件影响,同一场次降雨过后研究区地下水位升幅的大小顺序为：草甸地、沙丘区林地、固定沙丘、半固定沙丘、流动沙丘。2)在沙丘区,降雨量的大小是降雨影响地下水位变动的主要因素,大雨量降雨事件发生后,地下水位会有一段时间的下降期,其下降期时长和水位升幅与降雨量的大小成负、正相关,但当流动沙丘在降雨强度达到40 mm/h,半固定沙丘达到23.8mm/h时地下水位会发生突变。3)前次降雨事件若为有效降雨,且相距天数足够短,降雨就会通过影响沙丘干沙层厚度和土壤含水量进而促进本次降雨对地下水的补给,且对本次降雨前后沙丘区地下水位变动的影响较草甸区更大：当沙丘地区地下水位埋深小于某一临界值时,降雨过程中,地下水位上升速率和水位变幅会变大。4)草甸区地下水位对不同降雨强度的响应比沙丘区灵敏,且雨后地下水位的波动性更大；在一些较小级别的降雨过程中,草甸区地下水位在快速上升期的水位升幅会大于某些较大量级的降雨；耕地对干旱区草甸地地下水位的变化有明显影响。5)依据地质钻孔和物探资料,建立了科尔沁沙地典型沙丘—草甸相间地区三维地质模型和数学模型。并利用地下水数值模拟软件GMS建立了相应的水流数值模型,通过对模型进行多次调参、运行、识别,结果表明模型基本达到了对水文地质体的仿真,为该地区水文地质参数的确定、地下水资源的优化和该区生态环境的保护提供了科学依据。6)研究区模拟期内地下水系统的总补给量为321729.5 m3,总排泄量为-304092.4m3,均衡差为17637.2m3。其中,降雨入渗为主要补给来源,占总补给量的76.7%;蒸发为主要排泄项,占总排泄量的67.9%,畜牧及生活用水占地下水系统总排泄量的10.8%。
[Abstract]:In this paper, the data of natural rainfall and groundwater level in typical dune-meadow area of Horqin sandy land are observed jointly. The response relationship of groundwater level to different rainfall levels and the dynamic characteristics of groundwater level under different geomorphological types in Horqin Sandy Land are studied. The dynamic characteristics of groundwater level are studied, which is used as the reference basis for adjusting rainfall infiltration and recharge coefficient, combined with geological borehole, geophysical exploration and previous data. A three-dimensional numerical simulation model of groundwater flow is established by using GMS software. The main results obtained are: 1) influenced by groundwater table depth, vegetation types, soil physical properties and runoff recharge conditions. The order of the increase of groundwater level in the study area after the same rainfall was as follows: meadow land, woodland in sand dune area, fixed sand dune, semi-fixed sand dune, mobile sand dune. 2) in sand dune area, The magnitude of rainfall is the main factor that affects the change of groundwater level. After the heavy rainfall event, the groundwater level will have a period of decline, and the length of time and the increase of water level will be negative and positive correlation with the amount of rainfall. But when the flow dune reaches 40 mm / h, and the semi-fixed dune reaches 23.8mm / h, the groundwater level changes. 3) if the previous rainfall event is effective, and the number of days is short enough, Rainfall will contribute to the recharge of groundwater by influencing the thickness of dry sand layers and soil water content in the dunes. And the influence on the change of groundwater level in sand dune area before and after this rainfall is greater than that in meadow area: when the buried depth of underground water level in sand dune area is less than a certain critical value, during the rainfall process, The response of groundwater level to different rainfall intensity in meadow area is more sensitive than that in sand dune area, and the fluctuation of underground water level after rain is greater than that in sand dune area. The increase of groundwater level in meadow area during the rapid rising period will be larger than that of some larger order of magnitude rainfall, and the cultivated land has obvious influence on the change of groundwater level of meadow land in arid area. 5) according to the geological borehole and geophysical exploration data, The 3D geological model and mathematical model of typical sand dune-meadow interphase area in Horqin sandy land are established. The corresponding flow numerical model is established by using the groundwater numerical simulation software GMS. The results show that the model basically achieves the simulation of hydrogeological body, which is the determination of hydrogeological parameters in this area. The optimization of groundwater resources and the protection of ecological environment in this area provide a scientific basis. 6) during the simulation period of the study area, the total recharge of groundwater system is 321729.5 m3, the total discharge amount is -304092.4 m3, and the equilibrium difference is 17637.2 m3. Among them, rainfall infiltration is the main source of recharge. Evaporation is the main discharge item, accounting for 67.9% of the total excretion, and livestock and domestic water accounts for 10.8% of the total discharge of groundwater system.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641.1

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