Study On The Key Technologies For Earth-fill Shore Protection Construction And Its Application

With the completion of the Three Gorges Reservoir,more than 20 towns' residents migrate from existing inhabitancies,which makes the pinch of land use becomes more and more nakedness.Meanwhile,the area and the extent of Water-Level-Fluctuating Zone(WLFZ) whose area reaches 348.93km2 in the Three Gorges Reservoir is the biggest in the world.The stability of the slope in Water-Level-Fluctuating Zone threatens the safety of the bank slope and the constructions in it.Accordingly,the way to realize bank slope prevention and land use increase at one time is the issue that the State Council Gorges Project Construction Committee and local government think highly about.Consequently,this paper brings out Earth-fill shore-protection technology,which combine the protection of the Ningjiang road bedroad with bank slope protection makes use of the waste soil produced by the immigration project.The Earth-fill shore-protection technology forms a half-island along the reservoir,which can protect the bank slope,increase the urban land in the same way.The 30m high amplitude water level in the Three Gorges reservoir changes annually between 175m and 145m,which makes the soil-bank slope lied in Water-Level-Fluctuating Zone cyclically soak in the water.The cyclical soak destroys the natural equilibrium condition of original bank slope,causes geologic disasters such as collapse, landslide etc.Thesis analyzed the destabilizing mechanism of the bank slope based on the study on the reservoir-water acting mode and the cyclical variation of the water level affect on the stability of the bank slope;simulated the variation law of the groundwater seepage field and free surface under the variation of the water level adopted the model experiment;analyzed the variation law of the clay mineral component and geotechnical parameters through cyclic soak experiment.The destabilizing mechanism of the bank slope supply a theoretical basis for the protection of the bank slope.Earth-fill shore-protection technology is organic bonded by making artificial island and bank slope protection.While,during the building progress of the bank-protection works,three problems are inevitable:the water level fluctuation deteriorate the stability of the bank slope;the effective combination between original bank slope and the fill;intensive fluctuation of the bank slope caused by the reservoir water level's cyclic soak.Thesis adopted critical technologies such as spray drain,synchro drainage technology,excavating inverse steps at the surface between the fill and original bank slope,etc.Applicated these critical technologys at the Ningjiang island,the results show that on the one hand,the stability of the bank slope in Ningjiang island increased,the safety of the bank intensified,on the other hand,the urban land augmented.The Ningjiang island project,adopted critical technologys realized the function of adding land use,beautifying dthe travel environment.,forming a new travel landscape,it is a typical landscape reservation to the Water-Level-Fluctuating Zone in reservoir area.