A Study On The Forecasting Of Reservoir Bank Collapse And Its Controlling Measures In Three Gorges Areas

After Three Gorges Reservoir filling, bank collapse should occur in more reservoir banks which are distributed widely, and will generate severe hazards. But there is still no adaptive prediction method applied to the forecasting of bank collapse occurred in river channel reservoir built in mountain land, especially like Three Gorges Reservoir. Therefore, this paper establishes elementary prediction model and method system which can be applied to the situation of Three Gorges Areas, and puts forward corresponding reservoir bank prevention measures by means of investigating the rule of reservoir bank collapse, summarizing model of bank collapse, analyzing influence factors, and counting prediction parameters. All these are obtained from geological survey on the existing state of reservoir bank collapse occurred in Three Gorges Areas, especially in Wanzhou, and from the research on analogical reservoir bank collapse, physical modeling, and synthetically data analysis. The main research achievements of this paper are listed as follow.(1) On the basis of historical information collection and analysis, the author applies field investigation on existing state of reservoir bank collapse which happened in earlier impound period in Three Gorges Areas(especially in Wanzhou), and investigates bank collapse of analogical reservoir already operated secularly which has similar geology conditions to Three Gorges Reservoir. The engineering geology environment conditions are obtained, including the property of bank slope shape and structure, hydrogeologic condition, development and distribution of bank collapse generated in current water level, prediction parameters with actual measurement, and substance composition (especially the distribution as well as genetic reason and depth of loose quaternary debris). On this basis, combining physical modeling, the author summarizes investigation results and experimental phenomenon seriously, analyzes and generalizes the basic rule, distribution characteristic, generating condition, the main influence factors and model of reservoir bank collapse in mountain areas.(2) On the basis of preceding research, the author puts forward the main prediction principle and methods of reservoir bank collapse considering the characteristic of stage impounding and migration from original site at reservoir bank to its backside by stages, which can be used to forecast bank collapse occurred not only after impounding to 156m water level in relative short term but also in relative long period after reservoir normal operation. Furthermore, the technological process and steps used to forecast bank collapse are summarized, and the intense degree of bank failure are classified in this dissertation as...