Niaozhisuo Landslide Dynamic Process

Abstract

There are a series of large scale old seismic landslides in the Middle reach of Daduhe River, they played a major role in the evolution of landforms in the area, in which Niaozhisuo landslide is a typical one. Based on detailed site investigation and ATM geophysical exploration, combined with engineering geological condition analysis and research on basic characteristics and genetic mechanism, the landslide characteristics can be concluded as follows: Niaozhisuo landslide, formed in 2.0 × 104 years ago, is a huge seismic landslide on the left bank of the Daduhe river with a volume of 3.64 × 108 m3; The landslide is composed of huge blocks with cataclastic texture in the front part, middle cemented sandy granules in the main parts and well cemented sandy granules in the toe. The strong E-W compress in Paleozoic made the Proterozoic granite form the “bedding” rock, the flow direction of Daduhe River is parallel to the main strike of the texture planes, the quick cutting of Daduhe River and its branches created a projecting spur relief and strong unloading in high slope, frequent seismic activities speeded up the upper slope deformation, a strong seismic waves (Ms ≥ 7.5) were enlarged in the landslide source region of the high slope, at last, the slope failed under the huge seismic inertia force; After long time damming, it broke and Daduhe River was forced to change its river channel westward. Since the end of Late Pleistocene, the debris flow from Miaozi gully on the right bank has pushed the River channel eastward again, the front part of the landslide has been laterally eroded by Daduhe River, the part failure was frequent and the steep front has been left up to now.