Application and Evaluation of Geophysical Prospecting in Geological Disaster Investigation in Lhünzê County, Xizang Autonomous Region

The role of geophysical work in geological disaster investigation has gradually become more and more prominent, especially in high-altitude areas such as Tibet, "CT for the earth" to detect regional geological disasters is convenient and reliable; In this work, high density electrical profile survey was carried out in Longzi County, Xizang Autonomous Region to divide strata. The location, contour, scale and burial depth of anomalous bodies were accurately interpreted in combination with field investigation and drilling data, and the location and extension direction of special geological bodies in the target area were identified. In this work, ① the main strata in the working area are divided into three electrical layers by physical property measurement, namely, low resistivity layers (alluvial fan clay, subclay; Alluvial gravel) , mediumto- low resistance layer (gravel soil; Lower breccia soil; Highly weathered SLATE) , medium-to-high resistivity layer (surface breccia soil; Moderately weathered siliceous rock) ; (2) Combined with the ground survey, drilling records and other data, the deep geophysical characteristics of the section are analyzed, and the stratigraphic division is carried out according to the abnormal morphology and characteristics; (3) Highdensity inversion interpretation results show that the surface layer of landslide Ⅳ in Yumai-Sangqucun Road is dry breccia soil layer with large porosity, the middle and upper part is wet breccia soil layer, the bedrock is medium-strong weathered structural melange, and the sliding surface is the base covering surface with a depth of 0~20 meters. This work preliminarily identified the internal material structure of the landslide, providing a basis for comprehensively screening the hidden geological disaster situation in the working area, and identifying the distribution, development characteristics and harm degree of the geological disaster latent area within the work area.