| The upgrade of the navigation channel from Chongqing to Yibin in the upper reaches of the Yangtze River from grade III to grade II is an important measure for the implementation of the strategy for the development of the western region,and it is also an inevitable trend to accelerate the development of the upper reaches of the region.Shuishiba Dam Beach is located in the Baisha waterway in the upper reaches of the Yangtze River,with dry shallows and dangerous beaches.It is a shallow floodplain group with integrated beaches.The flow conditions in the beach section are complex,and the cause of the navigation is changeable.In this paper,theoretical analysis and two-dimensional mathematical model of water flow are used to analyze the flow characteristics,remediation parameters and remedial measures of the shallow reservoirs of the Shuishiba Dam,which can provide reference for the treatment methods of shallow riverbanks in the mountainous rivers.The work content and research results of the thesis mainly include:(1)The abundance of topography and hydrological data of the beach section was collected,and the evolution of the river bed and the characteristics of hydro-sedimentation were analyzed.Based on the measured data such as water level,velocity,and flow direction of the buoy in the beach section,the two-dimensional mathematical model of flow is verified and calculated,and the basic parameters suitable for the study of the river reach are given.(2)Based on the generalized tank model,the empirical relationship between the floating distance of the streamline,the cross-flow and the flow,and the calculation formula of the allowable cross-flow in the navigation channel were proposed through numerical simulation and analysis.The cross-flow value suitable for the dam section of the Shishiba dam was given.The range is 0.5~0.7m/s.Based on the natural reach of the natural division of the Shuishiba Dam,the flow characteristics of the intensive working conditions were calculated and analyzed.The distribution along the section modulus,channel flow velocity,aerodrome ratio,and beach determination was given.The results showed that the Shuishiba reach For the shallow river bank that divides the river,the shallow water in the upper reaches of Zhoutou is hindered by navigation,and it is dangerous to form a strong folder of water between the stone and the head of Zhoutou.(3)Through a variety of factors such as dam type,dam length,dam axis direction,dam position,and flow rate,single-factor and multi-factor calculations andanalysis have resulted in variations in flow velocity,cross-flow intensity,etc.Shunba is more suitable for the analysis of Zhoutouba dam head flow through the improvement of the Zhoutou rapids,and proposes an empirical formula for the lateral position of Chautouba dam.At the same time,the ratio of the width of the main channel to the total width of the river was calculated to estimate the position of the Zhoutou dam.The two methods were verified and applied to the regulation of the channel.(4)The speed control method proposed in this paper deduces the width of the rectification line,and controls the flow conditions of the beach section from the two aspects of sediment startup and beach speed.It is closely integrated with the actual beach section and is more consistent with conventional methods such as conventional hydraulics and bed-building flow methods.Actually,it is a reliable method for determining the parameters of mountain river shoal remediation.(5)This paper proposes the idea of regulating the flow regime and slowing down the cross flow in the dam constrained water flow to scour sediment,the dangerous section blasting reef and the Zhuzhoutoutou dam.Through several numerical simulations and optimization of the remediation scheme,the proposed scheme can basically reach the improvement.The purpose can provide technical support for the design and implementation of practical projects. |
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