GROWTH HISTORY OF HUANGTUPO LANDSLIDE: DOWN-SLOPE OVERLAPPING-LANDSLIDING-MODIFICATION

In 1995 two landslidesin the Huangtupo slope in the Three Gorges Reservoir region turned into a hot issue among the engineering geologists and the Chinese government.Although many researches have been made into the slope, there are still many controversiesover the characteristicsof the Huangtupo slope. Is the Huangtupo slope in the new county of Badong, Three Gorges Reservoir region an ancient landslide? If so, what was the scale of this ancient landslide? What is the relationship between the new landslides and the old landslides? The present paper proposes, on the basis of a great number of field observation references, the slope evolutionary pattern of deformation and instability in the multi_stages of down_slope overlapping, lands-liding, and modification. Before the landslide, the Huangtupo slope experienced the long_term down_slope overlapping classified as included toppling and deep_seated creeping, two basic slope deformation forms. The Huangtupo landslide, derived from the preceding down_slope overlapping, brought about the step_like land-form. The significant evidences for the landslide are the varied attitudesof structural surfaces and linesof out-crops in the slope and the presence of the sliding breccia zones.Since then, the Huangtupo landslide hasexpe-rienced small_scale overlapping modifications of landslides. The two landslides that occurred in 1995 were the result of the further modification. It is concluded that the rock slope deformation process of down_slope over-lapping_landsliding_modification is an organic one. This conclusion presents us with relatively precise under-standing of some important issues about the Huangtupo landslide and also with a typical example of the appli-cation of the tectonics to the research into slopes.