1 Necessity of design optimization of small sluice project
Shanghai itself is located in the lower reaches of the Yangtze River, with dense rivers and developed water system, in which numerous small sluice projects have been built. These small sluices are mainly used for flood control and drainage. In order to give full play to the role of small sluice project, it is necessary to optimize the design of small sluice project and build a sluice scale suitable for Shanghai's development requirements. In recent years, due to the abnormal climate, serious waterlogging disasters have occurred in Shanghai, which greatly hindered the development of the city and even endangered people's lives and property. Therefore, for the normal development and construction of the city, it is necessary to optimize the design of small sluice projects. Shanghai has a unique urban layout and construction land demand. Therefore, in the process of designing and optimizing small sluice projects, it also needs to go through two stages. First, the specific layout and construction scale of small sluice projects should be strictly based on urban planning and flood control and drainage requirements. During the design process and after the design is completed, the engineering design should be checked repeatedly and constantly reviewed and optimized. In the process of design and planning, the overall design is mainly aimed at sluice projects, while the related engineering research units are mainly aimed at individual sluice projects. Due to the influence of various factors, there is often a certain deviation between design and actual construction, which can not effectively achieve the combination of design and construction, thus leading to the unreasonable design of small sluice projects in scale. According to the actual situation in Shanghai, the construction scale of sluice is affected by different factors, and the problems that need to be paid attention to in each stage are also different. In order to make the small sluice fully play its role, it is necessary to optimize the design of the small sluice project.
2. Design optimization of small sluice project.
2. 1 lock chamber is arranged horizontally
Generally speaking, there are a large number of small sluices, among which single-hole sluices account for a large proportion. Usually, in the past, the side piers of small sluices were built by gravity side piers with large floor, which mainly resisted water pressure and earth pressure according to the weight of concrete itself. According to the design principle of aqueduct, in order to keep the stability of piers, it is necessary to install compression bars between piers, and use this compression bar to improve the compressive capacity of piers, effectively transform the structural form of piers, and transform the original pier form into a U-shaped structure. See figure 1 for details. Generally speaking, the bottom plate and side pier of small sluice are thick, and there is little difference between the width and height of the sluice hole. The earth pressure behind the pier is basically the same as that before the pier. According to this situation, the linear stiffness of small sluice can be calculated, and the calculation results show that the linear stiffness behind the pier is similar to that in front of the pier. Therefore, we can regard the pier and bottom plate as a whole statically indeterminate structure, and the calculation is shown in Figure 2. The design flow of Shanghai production sluice is 7.98m3/S, the sluice height is 3.0m, and the sluice width is 20m. The sluice adopts a U-shaped structure with pressure rods. The cross-sectional area of reinforced concrete in the lock chamber is 6.87m2, the amount of reinforced concrete is 4 1.22m3, and the reinforcement is only 0.7 tons. Specific gravity pier can reduce concrete by 7.74 cubic meters, steel bar by 0.4 tons, and reduce investment by 8,000 yuan. There is something wrong with this part. The width of the door is 20m, which is inconsistent with the picture below. This is not an example of a small sluice. Take a closer look. This is a senior engineer's paper, and there can be no low-level mistakes.
2.2 Longitudinal arrangement of piers
The length of small sluice chamber is generally 2 ~ 3 times of the water level difference between upstream and downstream. Generally, the pier thickness is 1/4 ~ 1/5 hole width, and the door slot has little stress. The distance between the gate slot and the upstream pier tip is generally 1/3 pier length, and the production bridge is mostly placed in front of the gate slot, so the 2/3 pier length behind the gate slot only bears the gate pressure and transverse shear. Making the pier behind the gate slot into a slope shape can not only reduce the concrete quantity of the pier, but also be beneficial to the stability of the lock chamber.
2.3 Others
For example, the upstream and downstream wing walls use less gravity, but more piers or empty box structures, and the engineering quantity will be reduced accordingly. In addition, the concrete bent is changed from double-column beam structure to double-column truss structure. The bending moment and shear force of the working bridge and bent are reduced, the section size and reinforcement are reduced, and the structure is more reasonable. In addition, in the engineering design stage, the drainage flow determined by the planning can neither be simply used as the design flow of the sluice nor simply increased, but should be reasonably determined on the basis of understanding the planning intention and boundary conditions, considering various influencing factors comprehensively. Small sluices in Shanghai can be roughly divided into two types. One is the control sluice and various water conservancy projects on both sides of the middle and upper reaches of Huangpu River. The water level difference between the upstream and downstream of these sluices is small, and the drainage is greatly affected by the jacking of the downstream water level. The design process should be enlarged as much as possible on the basis of planning. The other is the sluice of the tributaries along the Yangtze River and Hangzhou Bay. These sluices have large tidal range, low low tide level and good drainage conditions, and the design flow is equal to or slightly larger than the planned flow.
To sum up, in order to build a small sluice project suitable for Shanghai, we must design a high-quality small sluice project according to the specific situation of Shanghai and referring to relevant construction standards. In the process of design optimization of small sluice project, the design optimization of sluice chamber, pier and other parts is mainly carried out, and the optimized parts are repeatedly tested to ensure the design quality of small sluice project, make small sluice really play its role and provide sufficient water for urban residents.
I believe that after the above introduction, everyone has a certain understanding of the design optimization of small sluice projects. Welcome to Zhong Da for more information.
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