EFFECT ANALYSIS OF KARST AND HYDRODYNAMICS ON JIWEISHAN LANDSLIDE

The Jiweishan extra-large landslide is a unique large-scale rock slope instability mode in the karst mountain area of southwest China, and it has received great attention from engineering geology and other fields. A series of researches were carried out on the cause and mechanism of landslide, the starting and movement process of landslide, the distribution of deposits and secondary disasters, etc. Many results were obtained. For the structural plane and sliding plane of the landslide, it is considered that the vertical structural plane is composed of two groups, and the horizontal sliding plane is on the weak interlayer. This paper uses field geological survey, sample test and comprehensive analysis. It investigates the characteristics of karst and fissure development, the distribution of weak interlayer and its underlying nodular limestone, and the conditions of recharge and discharge of karst groundwater in landslide area. A large number of nodular limestone blocks are found in the landslide deposit. The relationship between karst and the vertical structural plane and horizontal sliding plane of the landslide are discussed. The main conclusions are as follows. (1)There are 3 groups of vertical structural planes. They are formed by 3 groups of structural fissures after long-term corrosion and erosion. (2)Part of the sliding plane passes through the weak interlayer, enters or passes through the nodular limestone, and the sliding plane is mainly controlled by bedding karst, weak cementation between rock layers, and weak interlayer. (3)The karst groundwater plays an expanding role on the vertical structural plane and the horizontal sliding plane in the process of landslide disaster. It has no hydrodynamic effect in the starting period of landslide. This study is of practical significance to the analysis and judgment of the genesis of Jiweishan landslide.