Study On Measurement Methods And Engineering Applications Of Reservoir Sedimentation Forms

Water is a necessity for human survival and development and an important national strategic resource.Reservoir is a kind of surface water conservancy engineering structure built for water storage and water flow regulation,which plays an important role in water security.In the process of reservoir operation,due to the influence of water potential change in the dam area to ease the backwater in the tail area of the reservoir,sediment and so on will inevitably silt up in the reservoir.Reservoir siltation not only reduces reservoir capacity,but also reduces flood control ability,which seriously affects the performance of reservoir benefit.Solving the problem of reservoir siltation is one of the fundamental ways to improve the flood control ability of reservoir and bring the project benefit into full play.This study intends to carry out the form measurement of the siltation at the bottom of the reservoir,so as to grasp the true condition of the siltation of the reservoir,which is of great scientific value and practical significance for scientific,reasonable,economical and effective cleaning of the siltation of the reservoir.Based on the analysis of the traditional underwater topographic survey method and its shortcomings,a simple and feasible method of reservoir silting form survey is proposed in this paper,that is,the silting survey is carried out by the modular unmanned remote control ship with field measuring instruments.Furthermore,relevant experimental studies were carried out to verify the high and flat accuracy of the method.In addition,field measurement was carried out in the front pool of The Warm Stone Soup pump station of Jiaodong water transfer project in Shandong Province,which further verified the feasibility of the method.Finally,the typical reservoir(Xueshan reservoir)in Shandong province is selected to carry out the engineering application research of reservoir siltation morphology survey,and the survey results are analyzed.The main conclusions are as follows:(1)Combined with global positioning system and underwater ultrasonic sounding technology,it can better realize the measurement of reservoir siltation pattern;The storage capacity of rizhao Qingfengling Reservoir was calculated by two different methods based on the previously obtained underwater point position coordinate data.Through comparative analysis,the calculation scheme of storage capacity and water surface area using discrete point method as the silting measurement method of unmanned remote control ship reservoir was determined.The unmanned remote control ship is independently developed,with high degree of automation,high measurement efficiency and cost saving,and can guarantee the safety of test personnel.(2)The measurement steps of the unmanned remote control ship were proposed:firstly,the horizontal two-dimensional geodetic coordinates of the point in the reservoir were measured,and then the vertical coordinates of the point were superimposed.Finally,the bottom shape of the point out of the reservoir could be calculated and analyzed through multi-point interpolation.The high precision,plane precision and feasibility of the method are verified by local water area test and field measurement.The results show that the measurement method proposed in this paper can realize the inversion of underwater three-dimensional topography well,and the accuracy can meet the measurement requirements.(3)Tai'an City medium-sized huangqian reservoir was selected as a typical reservoir,and the engineering application research of silting form measurement was carried out.The 3d coordinate data of 110,000 points measured in the field was processed,and the silting volume at different water levels of huangqian reservoir was obtained.The results show that the siltation volume of the reservoir below the xingli water level from 1973 to now is 2,344,700 m3,less than the estimated volume from 1960 to 1973(3.89 million m3).The difference is mainly due to the large variation of the water supply distribution of the reservoir and the increase of the vegetation coverage in the basin.(4)Selecting Xuanye Reservoir in Jinan city as a typical large reservoir,engineering application research of sedimentation form measurement was carried out,3d coordinate data of 280,000 points measured in the field were processed,and the area curves of reservoir water level?storage capacity and water level?water surface were obtained.The results show that the lowest elevation of the bottom of the reservoir is 201.12m,which is 10.08m lower than the measurement results in 1972.The total storage capacity of the reservoir increased by 29.05 million m3 and that of Xingli reservoir increased by 18.01 million m3.The main reason is that in recent years,sand mining in the middle and upper reaches of the reservoir has reduced the bottom elevation of the reservoir,and the storage capacity at all characteristic water levels has increased.