基于台址构造环境的有限元建模分析—以黔江台为例

Analyses of finite element model based on station’s tectonic environment: Taking Qianjiang station for example

  • 摘要: 为更好地应用形变观测数据、挖掘观测数据的物理含义,本文以黔江台为例,基于台址资料建立有限元模型,并结合仪器工作原理进一步分析观测数据。黔江台的台址构造环境较复杂,长期受到NW向压力的作用,发育大量NE向断层和褶皱,这些对该台站的观测数据均会产生一定影响。关于黔江台形变观测数据的有限元模型分析结果显示,志留纪页岩在压力作用下发生上隆弯曲变形,形成背斜,岩层整体朝SE倾斜,上覆岩层垂向变形大于水平变形,断层和褶皱轴的倾向影响着应力的传递。结合黔江台长期形变观测数据分析,本文认为模型结果合理地解释了压性构造背景下伸缩仪观测结果显示为张性的成因机理,垂直摆倾斜观测数据的长期趋势与模型结果一致,也得到了统一的机理解释,表明台址构造环境的有限元分析,有助于更好地认识和应用形变观测数据,可增强对观测数据物理本质的理解。

     

    Abstract: The site environment is the most direct factor affecting the observation data. In order to better apply the deformation observation data and find out the related physical meaning, this paper built a finite element model based on the deformation data from Qianjiang station, and further analyzed the observation data based on the working principle of the instrument. The tectonic environment of Qianjiang station is complex, a large number of northeast-trending faults and folds were developed due to the long time pressure in northwest direction, which has a certain influence on the observation data. The data analysis results based on the finite element model show that the Silurian shale appears as an uplift bending deformation and forms an anticline under the pressure, the whole rock layer is inclined to the southeast direction, the vertical deformation of the overlying rock is greater than the horizontal deformation, and the tendency of fault and fold-axis has influences on the transmission of stress. According to the long-term observation data from Qianjiang station, the results of the model can reasonably explain the mechanism of the expansion of the telescopic instrument under the structural background of the pressure. Furthermore, the model results are consistent with the long-term trend of the vertical pendulum, which is more in line with the physical meaning of the actual observation, that is, the finite element analysis of the site structure environment will help us to better understand and apply the deformation observation data, and thus explore the actual physical meaning of the observed data.

     

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