基于微动信号监测的碎石土滑坡滑动面(带)探测分析

Detection and Analysis of Sliding Surface (Zone) of Gravel Soil Landslide Based on Microtremor Signal Monitoring

为了解决传统获取滑坡地质结构特征技术(钻探、探槽、探坑和深孔位移监测等)耗时、耗力、耗费、对坡体造成损伤和勘察尺度受限等问题,以四川省理县通化乡西山村滑坡为例,通过在碎石土滑坡表面布设多台微动仪构建观测台阵,采集滑坡体内微动信号,并利用台站空间自相关法反演滑坡体剪切波速度结构,以定位滑动面的准确位置。结果表明,微动勘察法确定的滑坡潜在滑动面起伏形态清晰可见,位于强风化的千枚岩层内,探测结果与钻孔资料相吻合。该方法作为一种新的滑坡滑动面勘察手段,具有无需人工震源、不受地形限制、野外台阵布设灵活、探测深度大和分辨率高等特点,适合于高山峡谷区大型深层滑坡的调查研究。

To solve the problems of the traditional techniques for obtaining geological structure characteristics of landslide,such as drilling,trenching,trial pits,deep hole displacement monitoring,which are time-consuming,labor-consuming,cost-consuming,causing damage to the slope and limiting the survey scale,this paper,taking Xishan village landslide in Li county of Sichuan province as an example,collects the microtremor signals by laying observation array comprised of multiple micro-tremor instruments on the landslide surface and the spatial autocorrelation method(SPAC)is used to process the collected signals for the landslide shear wave velocity to locate accurate sliding surface.The results show that landslide potential sliding surface is located in weathered phyllite stratum with the clear undulation shape,and the detecting results are consistent with the drilling data.This method has the characteristics of no artificial source,no terrain limitation,flexible layout,deep probing depth and high detection resolution,which is suitable for the investigation of large deep landslide sliding surface in alpine valley area.