沧州地面沉降与地下水耦合模型研究

发布时间：2018-05-08 23:33

  本文选题：地面沉降 + 地下水　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：地面沉降是一类因人类工程活动引发或由自然因素驱使,以新生代以来地层中松散堆积土体的固结为主,发生的较大规模区域内地面高程降低的地质现象,亦是一类由水土相互作用下使得土体结构强度缓慢遭受破坏的地质灾害。华北平原地区自20世纪60年代以来,因长期过量开采地下水,形成了大量地下水位降深漏斗,引发了一系列地面沉降问题,沧州位于华北平原腹地,截止2015年其累计沉降量大于800mm的区域已超过3200km2,中心累计沉降量已超过2500mm。随着近年来京津冀一体化建设的加快,各类环境问题凸显,沧州市在2007~2010年采取一定管制开采地下水后,其中心沉降速率虽趋于缓和,但其沉降面积仍以较快速度向城镇发展。为更好地防控与监测地面沉降,通过数值模拟的方法重现其发展历史,分析其发展现状,成为近年来沧州地面沉降研究的主要任务。本文通过已有的监测记录结合前人研究经验,首先对沧州地区不同含水层的变形规律进行了讨论,通过分析土样物理力学性质随埋深的变化,掌握含水层的变形特征随埋深的规律;通过分析各类压缩实验结果,验证由过量开采地下水引发主要沉降的地层范围,评估由地下水动态变化对含水层沉降特征的影响,推算了含水层弹性释水参数、非弹性释水参数以及垂向渗透系数;其次结合研究区域的地质条件,应用GMS10.0中MODFLOW功能区块建立了应力期自2005年12月到2012年12月的沧州地区三维地下水流模型,利用SUB模块将其改进为一维固结情形下的水土耦合模型,并求解。根据2011-2012年地面沉降水准测量值,通过一系列拟合校正,反复调整参数、重新概化沉降土层建立了沧州地面沉降研究模型。最终,通过本次研究分析的沧州地区地面沉降特征,结合各类土工实验的结果,通过模拟软件,对含水层发生地面沉降的层位进行了滞后释水与非滞后释水的概化,建立起了较为复合实际情况的地面沉降模型,为今后该区域建立更为精确的地面沉降预测模型提供了参考思路。
[Abstract]:Land subsidence is a kind of geological phenomenon which is caused by human engineering activities or driven by natural factors and is dominated by the consolidation of loosely accumulated soil in the strata since the Cenozoic. It is also a kind of geological hazard that soil structure strength is destroyed slowly by soil and water interaction. Since the 1960s, a large number of groundwater funnels have been formed in the North China Plain, and Cangzhou is located in the hinterland of the North China Plain. Up to 2015, the accumulative settlement amount was more than 3200km2 in the area larger than 800mm, and more than 2500mm in the center. With the acceleration of the integrated construction of Beijing, Tianjin and Hebei in recent years, all kinds of environmental problems have been highlighted. After Cangzhou adopted certain regulation to exploit groundwater from 2007 to 2010, the central subsidence rate of Cangzhou City tended to ease, but its subsidence area still developed to towns at a relatively fast speed. In order to better prevent and control and monitor land subsidence, it is the main task of Cangzhou land subsidence research in recent years to reproduce its development history and analyze its development status by numerical simulation. In this paper, based on the existing monitoring records and previous research experience, the deformation law of different aquifers in Cangzhou area is discussed, and the variation of physical and mechanical properties of soil samples with buried depth is analyzed. By analyzing the results of various compression experiments, the author verifies the stratigraphic range of the main subsidence caused by over-exploitation of groundwater, and evaluates the influence of the dynamic change of groundwater on the characteristics of aquifer settlement. The elastic water release parameters, the inelastic water release parameters and the vertical permeability coefficient of the aquifer are calculated. Secondly, the geological conditions of the studied area are considered. The three-dimensional groundwater flow model of Cangzhou region with stress period from December 2005 to December 2012 was established by using MODFLOW functional block in GMS10.0. The model was improved into a soil and water coupling model under one-dimensional consolidation by using SUB module and solved. According to the measured values of land subsidence leveling in 2011-2012, the study model of Cangzhou land subsidence is established through a series of fitting and correction, and the parameters are adjusted repeatedly. Finally, through the analysis of the characteristics of land subsidence in Cangzhou area, combined with the results of various geotechnical experiments, and through the simulation software, the ground subsidence of the aquifer is generalized by the delayed and undelayed water release. A more complex ground subsidence model is established, which provides a reference for the establishment of a more accurate land subsidence prediction model in the region in the future.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.26;P641
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本文编号：1863591