青岛地区钻孔倾斜仪地铁干扰定量分析

Quantitative analysis of subway interference on borehole tiltmeter in the Qingdao area

摘要:

受青岛地铁运行影响,青岛地区钻孔倾斜仪存在高频干扰,每日干扰出现时间与地铁运行时间一致,通过定性分析青岛地区五套钻孔倾斜仪数据,发现距离地铁2 km内的倾斜仪会受到地铁干扰,当距离超过15 km时,不再受地铁干扰。为定量分析地铁的干扰特征,利用变分模态分解(VMD)方法对青岛地区受地铁干扰的倾斜仪数据进行分解,同时结合广义S变换，以验证VMD分解层数K值的准确性及去噪的有效性,分析得出青岛地区受不同地铁线路干扰的钻孔倾斜仪均具有5个干扰模态分量。去除地铁干扰分量并重构数据后,数据信噪比提升,有效提高了数据可用性。

Abstract:

Due to the subway's operations, high-frequency interference occurs on the tiltmeters in the Qingdao area. Furthermore, the daily interference occurs simultaneously with the subway's operation time. After conducting a qualitative analysis of data obtained from five sets of borehole tiltmeters in the Qingdao area, the results reveal that the tiltmeters within 2 km of the subway are disturbed by the subway's operations. However, when the distance exceeds 15 km, the tiltmeters are no longer affected by subway interference. At the same time, to quantitatively analyze the interference characteristics of the subway, the variational mode decomposition (VMD) method was used in this study to decompose the data of tiltmeters affected by the Qingdao subway interference. The accuracy of the K value of the VMD decomposition layer and the effectiveness of denoising were also verified using the generalized S transform. The findings indicate that the borehole tiltmeters undergoing interference from different subway lines in Qingdao have five interference mode components. Upon removing these components and reconstructing the data, the signal-to-noise ratio of the data is improved, effectively improving data availability.