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沧州地区地面沉降成因机理及沉降量预测研究

Research on Land Subsidence Mechanism and Prediction of Settlement in Cangzhou Area

【作者】 朱菊艳

【导师】 李文鹏;

【作者基本信息】 中国地质大学(北京) , 地下水科学与工程, 2014, 博士

【摘要】 由于工业化和城市化的快速发展,华北平原普遍发生了地面沉降。地面沉降已经成为影响区域经济社会发展的主要环境问题。本论文以华北平原地面沉降典型区沧州地区为研究对象,系统分析了该地区的地面沉降成因机理,应用地下水数值模型模拟了地下水动力场在时、空方面的变化和发展,预测了该区地面沉降的发展趋势。全面搜集并分析了研究区地面沉降相关环境地质资料,从区域地质环境、水文地质条件入手,结合MapGIS空间分析方法,得出了沧州地区乃至整个华北平原的地面沉降与深层地下水开采之间的量化关系。随后,选择沧州地面沉降区的典型试验孔为研究对象,对粘性土体物理特征、土体压缩变形规律及粘性土渗透特征进行分析,进而对沧州地区地面沉降成因机理进行了研究。根据区域地层结构及粘性土渗透特征,利用Processing Modflow软件构建了沧州地区地下水水流模型;根据地下水模型对地下水位进行预测,得到2020年两种开采条件下第Ⅲ含水层的最大水位埋深分别为106.8m和101.2m;结合水位埋深与累计沉降量关系及地下水开采量与累计沉降量关系,建立回归模型,从“点”上对沧州地区2020年地面沉降发展趋势进行预测,在现状开采下,两种方程得到的最大累计沉降量分别为3002.7mm和3004.7mm;压采条件下,两种方程得到的最大累计沉降量分别为2590.2mm和2986.3mm。预测结果表明,预测期内,沧州市地面沉降中心仍然位于沧州市区,进一步说明地下水开采与地面沉降的关系,为地面沉降综合治理及预防提供了依据。最后,选择京沪高铁沧州北段为研究区,从该区的地形、地貌、工程地质等条件出发,结合综合分析法、层次分析法,并应用ArcGIS软件构建了地面沉降危险性评价模型,对该研究区的地面沉降危险性进行了分区评价,并提出了相应的地面沉降防治措施,为城市规划、建设及未来发展提供了基础。

【Abstract】 Due to rapid development of industrialization and urbanization, land subsidenceoccurs commonly in the North China Plain, and has become the main environmentalproblem factor impacting regional sustainable economic and social development.This thesis choose Cangzhou, a typical land subsidence area in the North ChinaPlain as the study object, systematically analyzes the mechanism of land subsidence inthis area, simulates the temporal and saptial change and development ofthe groundwater dynamic field by a groundwater numerical model and then forecaststhe development trend of land subsidence in Cangzhou area.The geological environment data related to land subsidence have been collectedand analyzed comprehensively. With MapGIS spatial analysis method and startingfrom the regional geological and hydrogeological conditions, quantitative relationshipbetween ground settlement and deep groundwater exploitation is concluded inCangzhou region and the North China Plain. Then a typical test borehole in landsubsidence area of Cangzhou was selected to analyze the physical characteristics,compression deformation laws, and permeability characteristics of clay. At last,the mechanism of land subsidence in Cangzhou area is analyzedAccording to regional stratigraphic structure and permeability characteristics ofclay, a groundwater flow model of cangzhou area was built with the ProcessingModflow. With this contructed groundwater model, the maximum water depths of theIII aquifer in two mining conditions in2020were predicted to be106.8m and101.2m, respectively. Regression equations were contructed between water leveldepth and accumulative settlement, and between groundwater abstraction andaccumulative settlement, respectively. With these regression equations, thedevelopment trend of land subsidence in Cangzhou in2020was predicted. The resultsshow that the maximum accumulative subsidence is predicted to be3002.7mm and3004.7mm respectively in the current abstraction pattern, and predicted to be2590.2m and2986.3mm respectively in the reduction of abstraction scenario. Theresults also indicate that the center of ground subsidence is still located in Cangzhou City in the prediction period, which further illustrate the relationshipbetween groundwater exploitation and land subsidence and provide the basis for thecomprehensive management and prevention of land subsidence.Finally, the north section in Cangzhou of the Beijing-Shanghai High-speedRailway was selected as the study area. With considering some facters such as theterrain, landform and engineering geological conditions, using the AHP method andcomprehensive analysis method, a hazard evaluation model was constructed withArcGIS to conduct division evaluation of hazard in the study area. Base on theevaluation results, corresponding prevention measures of ground settlement are putforward, providing the basis for city planning, construction and development in thefuture.

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