Effect Evaluation Of The R Zhao Reservior Reinforced With Concrete Cut-off Wall

Utilizing concrete cut-off wall to reinforce dangerously weak reservoir is one of the methods commonly used in China. Millions of square meter wall have been completed for several applications so far. Considering the academic significance and engineering valuation,it is meaningful for us to evaluate the reinforcement effect.Being based on summarizing the existing research and combining R Zhao reservoir engineering,this thesis mostly covers the following aspects: parametric inversion of earth-rock dam's mechanics coefficient after strengthening, computer simulation of construction process of embankment dam, emulation of operational process after being completed and feedback analysis of reinforcement using impervious wall.1. Applying nonlinear incremental finite element method, the stress, strain and displacement conditions of the earth and rock-fill dam are researched and discussed. Taking R Zhao reservoir as an example to calculate, the results show that it had great displacement the year it was constructed, which mostly ascribe to the base did not deal with well and the poorly-graded soil and rock material.2. According to the measurement results of piezometer tube and utilizing BP neural network model, the seepage coefficients before consolidation are inverted. Using coupling method between seepage field and stress field, steady seepage field is researched. At the same time, unsteady seepage field during water head descends of the dam is also researched making use of finite element method.From the calculation results of R Zhao reservoir, we can see that the escape point of downstream slope is higher before reinforcement which changes to be lower after strengthening. During the water head descends, the seepage line reduces gradually and the water head of the upstream areas increases slowly. Zero water pressure-line descends with hysteresis phenomenon comparing to descend of water head. The descending of the upriver seepage line is rapider than other position which demonstrates that upriver dam has seepage along the slope because of the outflow of saturated pore water. The more rapidly the water head descends, the earlier and more evidence the lag and seepage along the slope area, corresponding to which the greater the seepage hydrodynamic pressure along the dam slope and the more the seepage-steady in the dam is affected badly.3. Being based on Mohr-Column theory and adopting genetic algorithm, the mechanics coefficients before strengthening is inverted. Considering coupling of stress field and seepage field, the slope stability condition before and after reinforcement is researched.The computing results of R Zhao reservoir show that the upriver slope stability is well while the status of downstream slope is bad before consolidating. After strengthening, the stability of downstream slope turns to be better evidently and meets code requirement. During the water head descends, the stability coefficient of upriver slope reduces firstly, then it enlarges gradually after coming to the minimum because of the adverse effect describe to seepage hydrodynamic pressure along the dam slope.4. The dynamic property and the affect to it with different strengthening measure are researched. The results show that using diaphragm wall only to reinforce dyke has little effect for dynamic trait, the liquefaction zone after strengthening is almost same as the one before strengthening. After stiffening the dam adopting mix measures with cut-off wall, shaking sand slope and stacking rock, the dynamic trait of dyke is improved evidently and liquefaction zone decreases obviously. So we can take the conclusion that shaking sand slope and rising gravity of dam are important measures for improving dynamic property and ability of anti-liquefaction of the soil dam.