The Application Of Cutoff Wall In The Project Of Danger Prevention And Strengthening

Near 90,000 reservoirs, in different scales, have been constructed in China. As returns are gained, many faulty and dangerous cases and even dam failure occurred, which lead into heavy losses of people's life and property. To promote the benefit of projects and achieve the maintenance and increment of the national assets, it is necessary to summarize and popularize the reinforcing technique of earth-rock dams.Cutoff wall technique has been introduced nearly half century. The design theory and construction method of cutoff wall are improved and explored incessantly, and the application extends from hydraulic engineering to municipal construction, traffic and shipping Engineering.In this paper, based on Xiangshui River reservoir project, the dam of the reservoir is prevented from seepage by means of cutoff wall. The design scheme, construction technique and strengthening effect are studied systemically.According to the characteristics of Xiangshui River reservoir, two schemes of anti-seepage are compared and assessed, then the scheme of cutoff wall is chosen in light of technique, costs, construction conditions and time limit of the project. In the design of concrete, the clay and flyash, as gelatinous material, are mixed in concrete according to equivalent weight replacement method and excessive weight replacement method, respectively. In the tests of mix proportion, the combination of orthotropic experiments with multi-factor and different levels is adopted, and the experiment data are analyzed by means of a data analysis software named 'SPSS'. In the construction of cutoff wall, the length of grooves is varied in accordance with the different geological conditions. After accomplishment of the construction of cutoff wall, water pressure tests and quality inspection were conducted, and the results indicate that the dam meets the anti-seepage request.The above research results have applied successfully to the design and construction of Xiangshui River reservoir project. The results can be used for reference for the strengthening treatment of other faulty and dangerous reservoirs, and can also be accumulated as the experience for study strengthening technique of the faulty and dangerous reservoirs.