Study On Hydraulic Calculational Methods Of End-dump Closure With Single Embankment Under The Condition Of Single Tunnel Diversion

Closure plays a key role in the construction of water resources and hydropower projects, which have a direct influence on the period, investment and benefits of one project. Higher water head closure has become a trend with the development of river way closure. It can reduce construction of diversion structures. Development of modern transportation and cranes has made it possible to realize higher water head closure with heavier stones and higher casting strength, but at the same time it has increased difficulty of closure. In addition, as a major objective factor that affects the result of closure, hydraulic parameters of closure gap are always changing in end-dump closure. If various hydraulic parameters can be obtained by theoretic calculation before closure, it will be possible to estimate in advance what may happen during the course of closure and make necessary preparations to ensure a more economic and safe operation.With the premise of summarizing current status of investigations and a final goal of solving closure gap drop, this paper adopts calculational methods of hydraulics, takes the model of single embankment end-dump with double closure and one tunnel diversion as an example, elaborates on the calculation of hydraulic parameters of gap in the course of closure, and makes analysis and researches on this calculation. For practical application, first, establish a model of hydraulic calculation of combined discharge for tunnel diversion and closure gap discharge; next, apply the concept of head loss to hydraulic calculation of closure and obtain the curve of flow level variations in the lower reaches of embankment during the course of closure and acquire the resolution of hydraulic parameters of closure gap.Finally, calculate on the actual situations of Sanbanxi Project on the basis of above theoretic outcome of researches and achieve a result accordant with the data of model test; and, taking this project as the object, make a study on the influence of water level variations at the infall of tunnel exit on hydraulic parameters of closure gap and conducts sensitivity analysis.