| The stability of the high rock slopes under complex geological conditions is animportant engineering technical problem of the large-scale water-power project constructionin China. Nuozadu Hydro-Power Station is associated with a 261.5 m high dam and 5850MW installed capacity, and under complex geological conditions. There will form many highrock slopes in different place alter the project are constructed. The scale, geological conditionand structure of these slopes are different. The deformation-failure models of slopes arecomplex and various. The stable problem of excavation slopes is very important. Based onthe research of engineering geological conditions and complex slope rock mass structurecharacter, this dissertation estimate and forecast the slope stability of different kind rock massstructure by all kinds of methods.A set of technical and methodological system on stability research of high slope in rockengineering under complex geological conditions will be established by use of advancedtheory and method in modern geologic engineering, geotechnical engineering, rock massmechanics. The research results have not only made progress in elementary theories andmethods but also directed engineering practice, and can be obtained as follows:1. Geological conditions in the research area were investigated, and it is conditions thatformation of the rock mass structure in the region suffered from complex reconstructionprocess. The tectonic system was formed by six times structural change, and the maintectonic framework presented faults and joints. The engineering area can be divided into sixengineering geological areas considering rock character, geological structure, weathering,unloading and rock mass structure types.2. For the first time, we find that there was a large-scale vault structure in the west sideof engineering area. The quick uplifting of the vault formed the tension fracture compositionof radiated and circular fracture. As the tension fractures exist, which cause the rock massstructure more complex and lowing the strength of the engineering slope.3. The method of filed investigation and modified method of CSMR (China slope massrating) has been put forward, by applying the latest findings about the quality classification ofslope stability. Based on the lasted finding of Hoek-Brown failure criterion, research themechanical characteristic of slopes rock mass. The shear strength and deformation parameterof different levels rock mass has been put forward, by combining the parameter of field experiment.4. Based on rock mass structure research, the classification system of geologicalengineering about slope rock mass has been established, and the slopes have been divided 6groups and 14 sub-groups. The slopes deformation failure mechanism has beensystematically research, combined with the type of geological structure and deformationfailure mode of the slope.5. Aimed at the representative geological structure slopes, namely high-angle over-dipstratified structure slope, high-angle anti-dip stratified structure slope, low-angle anti-dipstratified structure slope, disintegrated structure slopes, utilizing mechanism analysis ofgeological process and measuring methodological theory in the geotechnical engineering, theslopes stability analysis and evaluation has been systematically summarized. At the sametime, a series of technique and methods system about analyzing and evaluating the slopestability of different structure type has been put forward, as well as presenting thereinforcement recommendation.(1)High-angle over-dip stratified structure slope is liable to plane landslide or falling, thestability of which can be analyzed through Limit equilibrium method and FLAC. The mostattractive options are reinforcement by means of cables on the slope of middle and upper, andreduction cutting the slope toe.(2)Topples is the main failure mode of the high-angle anti-dip stratified structure slope.The efficient way to analyze the stability of the slope is Distinct Element Method. Measuressuch as anchor to reinforce the slope in order to prevent the rock mass destroy.(3)There is weak interlayer in the rock mass of low-angle anti-dip stratified structureslopes. The main failure mode is sliding and compression cracking or plastic flowing andfracturing, and the slope is liable to flat-push landslide on the condition of high strengthstorm rainfall. The slope stability can be analyzed through Finite Element Method and FLAC,It is necessary of waterproofing and drainage works in the slope, and the most options arereinforcement by means of cables on place of weak interlayer and fault in the middle andupper slope.(4)Disintegrated structure slopes main failure mode is circular slide and wedge slide, thestability of which can be analyzed through Limit equilibrium method and Finite DifferenceMethod. Timely support methods such as anchor to reinforce the slope toe and fault position. |
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