The Design Of Qianzuzi Reservoir Reinforcement Scheme And The Analysis And Research Of Related Problems

The sand-laden rivers in northern China were built in the middle and small reservoirs in the 1950 s and 1960 s,and there were problems such as incomplete flood discharge and sediment discharge facilities and poor scheduling management.In addition,the hidden dangers of various diseases and hazards were becoming increasingly prominent.In addition to the traditional dam area buildings need to be reinforced from the aspect of structural safety,due to the congenital deficiency of the original design and many other reasons,the problem of sediment deposition in the reservoir area is also very serious,especially the phenomenon of silting up and scraping of small reservoirs in the Yellow River Basin has been very common.Solving the problem of sediment deposition in small reservoirs and realizing the long-term sustainable use of water source projects in small reservoirs are a long-term hot issue in reservoir reinforcement.Based on the analysis and study of the conventional reinforcement scheme for the dam area of Qianzuizi Reservoir,according to the characteristics of the reservoir that has been silted up and scrapped,this paper focuses on the siltation of small reservoirs,which is a common representative safety hazard in small reservoir areas.At the same time,in view of the practical requirement that a large number of small reservoirs that have been out of repair for a long time need to be rebuilt with additional discharge and sediment discharge tunnels,based on the existing principles and methods for determining the discharge scale of the discharge and sediment discharge tunnels in the reservoirs with sediment-laden rivers,the influence of high concentration sediment-laden flow in the reservoirs with sediment-laden rivers on the discharge capacity of the discharge and sediment discharge tunnels is discussed through the generalized model test.The specific work and main achievements are summarized as follows :1.According to the basic requirements of the reinforcement work of various types of buildings in the dam area,and in view of the relatively insufficient hydrological data of the reservoir project,under the guidance of the current norms and regulations,the hydrological basic data of the basin where Qianzuizi Reservoir is located are reviewed,analyzed and confirmed.At the same time,according to the collection and analysis of the main geological data in the similar area,the regional and geological conditions of the dam site of Qianzuizi Reservoir are reviewed,analyzed and confirmed,which provides the basis for the analysis and demonstration of the reinforcement work of the dam area of the reservoir project and the treatment scheme of the sediment problem in the reservoir area.2.In view of the dangerous condition of the building in the dam area of the reservoir,a series of dam reinforcement schemes are proposed by reviewing and calculating the crest elevation,dam seepage and dam stability,such as heightening the crest of the dam,removing the original dry masonry in the upstream of the dam,renovating the downstream abutment and adding drainage facilities.In view of the relevant conclusions and suggestions in the safety appraisal opinions,it is proposed that the spillway reinforcement should not change the grade,position and shape of the original buildings.Under the condition of meeting the requirements of flood discharge,the reinforcement treatment of both sides of the sidewall and the bottom slope are carried out.Sand drain hole body and bottom board for masonry lining,the external wall with sand paste surface,dense backfill between the inner wall and weathered masonry bedrock surface;In view of the problem that the poor external traffic conditions of the original project seriously affect the flood control safety,the flood control highway is added to connect with the outside world.According to the requirements of relevant specifications and combined with the actual situation of the dam,the reinforcement scheme of the dam area buildings clearly puts forward the long-term monitoring projects such as deformation observation,dam foundation,dam seepage pressure monitoring and hydrological and meteorological observation.3.In view of the current situation that the sediment in the reservoir area of Qianzuizi reservoir is heavily silted up,which leads to the serious harm of sediment in the reservoir area filled with scrapped reservoirs,this paper comprehensively absorbs the experience of sediment discharge and dredging at home and abroad,especially considering the characteristics of sediment dredging construction after the filling and scrapping of small reservoirs,and puts forward the preliminary scheme of sediment dredging in Qianzuizi reservoir by combining hydraulic dredging technology with pipeline hydraulic transportation technology.4.Aiming at the problem that whether the sediment concentration of the sediment-laden flow affects the flow capacity of the flood discharge tunnel in the sand-laden river reservoir which has been concerned by the relevant technical departments of water conservancy projects,a brief analysis and demonstration are carried out through the generalized hydraulic model test,and the preliminary conclusion that the influence of sediment concentration on the flow capacity of the sediment discharge tunnel can be ignored is preliminarily obtained,which can be used as a reference for the design of the flow capacity of the sediment discharge tunnel.