Study On The Methods Of Predicting Soil Reservoir Bank Collapse Considering The Hydrodynamic Conditions

The reservoir banks are always changed by the natural force. on the one hand, Waves and shore flow impact or abrasion the banks; On the other hand, they will transport the material that was by erosion and other sources of sediment to the bank and accumulate them, the both of which cause advance and retreat of the banks. During the process of collapsing and rebuilding , the harm caused to the reservoir area is obvious. For example, if they happened to collapse, a large number of rock and soil will slip into the hangar, resulting in additional deposition, reducing the effective storage capacity, which harm Seriously the safety of the surrounding architecture, and make a large number of the beach collapse Etc. Therefore, accurate analysis and evaluation of reservoir bank stability and prediction the scope of bank collapse are particularly important.Taking a bank of the Three Gorges reservoir area for example, the paper discussed the method of predicting soil reservoir bank collapse considering the hydrodynamic conditions. The study area is located on the right bank of the Yangtze River.175m upstream of the Three Gorges reservoir water, the water level of this paragraph is 181.6m. According to preliminary conclusions of the investigation, there is the risk of reservoir banks collapsed. By Analysis of geo-environmental conditions in the study area, the factors which accept the impacts of bank collaps are mainly geological factors, reservoir water, rainfall and human activities.Based on the conclusion of traditional forecasting methods of bank collapse, this paper introduced hydrodynamic-soil-mechanic method into predicting bank collapse in the study area. Under lateral erosion, deeply discussed the impacts of channel lateral widening and bed degradation in appraising of reservoir bank stability and predicting the scope of bank collapse, and systematically summarized up and perfected the theoretical system of this method. The hydrodynamic-soil-mechanic method mainly includes calculating bed sediment deformation by principle of hydrodynamic, appraising of reservoir bank stability by Principles of Soil Mechanics, then predicting the scope of bank collapse.Based on the principle of hydrodynamic-soil-mechanic method, used VC++ language, developed a soil slope stability evaluation system (Referred to as SM-RD system). The use of this system, selected the section of 3,7,10 and 15 under 6 different working conditions, considered washing for 20 days, calculated the distance channel lateral widening and appraised of reservoir bank stability of the study area. Evaluation results show that the stability coefficient reduce: under condition 1, section 10-10 ' turns into the basic steady-state; under condition 3, section 3-3′,10-10′,15-15′turn into the basic steady-state; under condition 6, section7-7′,10-10′becomes less stable. Compared with traditional forecasting methods, the results which appraise reservoir bank stability by hydrodynamic-soil-mechanic method are more in line with the development trend of the study area banks.Finally, compared the results calculated by hydrodynamic-soil-mechanic method to which are calculated by traditional forecasting methods, the paper deeply discussed morphological changes of reservoir banks, the impact of factors of reservoir banks back, changes in the stability of different conditions, changes in the stability in any time, which finally lay a theoretical foundation of hydrodynamic-soil-mechanic method in predicting soil reservoir bank collapse.