洞体应变观测中荷载干扰实例分析

2012年以来,河北省易县地震台SS-Y型伸缩仪NE向观测曲线转折异常,调查发现,该台周边采石场荷载变化可能是导致数据变化的原因。因此,利用三维实体结构有限元模型,结合荷载变化与地应变异常时间进行对比分析,结果表明:计算得到的伸缩仪NE向年变幅理论值为2.62×10~(-7),而实际观测异常年变幅为4.08×10~(-7),实测应变值几乎是理论值的2倍,可见应变异常变化与采石造成的荷载变化有关。

Case analysis of load interference of cave strain observation

Since the year 2012, the observation curve of NE component of SS-Y extensometer at Yixian Seismic Station in Hebei Province has shown unusual transition. The investigation discovered that the surrounding quarries load variations may be the cause of the data change. Therefore, using three-dimensional solid structural finite element models, combined with load change and analysis on strain anomaly comparison, it finally indicated:the theoretical year amplitude value of NE component of extensometer computed is 2.62×10^-7, but actual observes unusual annual variation for 4.08×10^-7, the actual strain value is nearly theoretical value 2 times. Obviously, the strain anomaly associated with load changes caused by quarrying.