Who has a plan for construction diversion? What are the methods of construction diversion

I have never heard of the need for diversion in farmland water conservancy construction.

The general water conservancy project diversion methods include open channel diversion, tunnel diversion, and narrow riverbed diversion.

We are very happy to answer for you what are the methods of construction diversion: the basic methods of construction guide socks can be roughly divided into two categories: one is the full-section cofferdam method diversion, that is, the cofferdam is used to block the riverbed, and all the water flow is exhausted through the pre-repaired diversion and drainage building logistics; The other type is the segmented cofferdam method, that is, the water flow is discharged through the narrow riverbed outside the riverbed, and later discharged through the gap reserved by the dam body, the bottom hole or other drainage structures.

However, whether it is a segmented cofferdam method or a full-section cofferdam method for diversion, when the water-retaining cofferdam can pass the water, a special diversion method for submerging the foundation pit can be adopted.

The construction of water conservancy and hydropower projects is carried out in the large and small rivers or coastal areas of the lake, and a considerable part of the buildings are located in the riverbed, and the construction of these buildings must create the conditions for dry land construction, in order to solve this contradiction, it is necessary to build a cofferdam enclosure foundation pit in the riverbed, and the upstream water volume of each period in the river channel is directed downstream in a predetermined way, which is the construction diversion.

The construction diversion should first build a diversion and drainage building, and then build a cofferdam to intercept the river channel, forcing the river flow to be discharged from the diversion and drainage building. Therefore, although the construction diversion is a temporary project, it is a vital unit project in the construction of the whole water conservancy and hydropower project, it is not only related to the construction progress of the whole project and the completion time of the project, but also has a great impact on the careful selection of the construction method, the layout of the construction site and the cost of the project, for example: when a certain water conservancy engineer which age shoots the construction diversion standard adopted in the construction is too low, and the actual water flow upstream is greater than the construction diversion flow adopted by the design, this will lead to the cofferdam project failure, The flooding of the foundation pit, especially when the project is flooded, will directly affect the success or failure of the project construction and the safety of people's lives and property downstream; On the contrary, the selection of construction diversion standards is too high, which will increase the construction quantity of diversion and drainage buildings and cofferdam projects, so that the cost of the project will increase and cause waste.

In order to solve the problem of construction diversion, the construction diversion design must be done in the construction organization design of the project, and its design task is: to analyze and study the local natural conditions, engineering characteristics and the demand for water resources of other industries to select the diversion scheme and divide the diversion period. Select the diversion standard and diversion design flow, determine the type, layout, structure and size of the diversion building, draw up the construction method of "demolition" and plugging of the diversion building, draw up the technical measures of river interception "flood control and foundation pit drainage, and select the most economical and reasonable diversion scheme through technical and economic comparison.

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What are the methods of choosing the diversion scheme as follows: 1, the construction diversion can be divided into the phased cofferdam diversion mode and the cofferdam diversion mode of the riverbed at one time, and the combination diversion of the dam body bottom hole in the construction process, the gap diversion and the different drainage buildings are included with the open channel diversion, tunnel diversion, culvert pipe diversion, and the dam body bottom hole diversion in the construction process. The construction diversion method should be formulated after a comprehensive comparison.

2. The following principles should be observed in the selection of construction diversion methods: (1) adapt to the hydrological characteristics of the river and the topography and geological conditions; (2) The construction period of the project is short, and the benefits of the project are fast; (3) The construction of the project is safe, flexible and convenient; (4) Combine and utilize permanent buildings to reduce the amount of diversion engineering and investment; (5) Adapt to the requirements of navigation, ice discharge, water supply, etc.; (6) river interception, cofferdam water retention, dam body flooding, plugging diversion holes, water storage and water supply and other early and late diversion can be reasonably connected in the construction period. 3, when using the phased cofferdam diversion mode, the position of the first phase of the cofferdam should be determined after analyzing the hydraulic hub layout, the topography where the longitudinal cofferdam is located, the geological and hydraulic conditions of the year, the construction site and the traffic road entering the foundation pit.

Permanent buildings for power generation, navigation, ice discharge, sand discharge and later diversion should be constructed in the first phase. When using tunnel diversion, the size and quantity of tunnel section are determined according to factors such as river hydrological characteristics, rock integrity and cofferdam operating conditions. When the diversion tunnel is used in different diversion stages, it should be designed according to the flood standard of the control phase.

Under the following circumstances, it is advisable to adopt the diversion mode of cofferdam water retention in the dry season: (1) when the permanent building (or temporary water retention section) can be built to the flood level of the dam body in the flood season above the flood standard in a dry season; (2) Although the foundation pit is submerged in the flood season, the impact on the progress of the project is small and the inundation loss is not large.

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<>1.The basic mode of construction diversion can be divided into two categories: staged cofferdam diversion and one-time damming of the riverbed cofferdam diversion. According to the type of drainage building, it can be divided into:

Open channel diversion, tunnel diversion, culvert diversion, dam bottom hole diversion, gap diversion and combined diversion of different drainage buildings in the construction process. 2.Staged cofferdam diversion.

It is suitable for projects with wide river bed, large flow and long construction period, especially for navigable and serious ice rivers, and this diversion method has low cost. According to the characteristics of the drainage channel in different periods, the phased cofferdam diversion includes the diversion of narrow riverbed and the diversion of water through buildings that have been built or are under construction. 3.

A cofferdam to block the riverbed for diversion. It is suitable for rivers with small flow and narrow river channels in the dry season, and can be divided into open channel diversion, tunnel diversion, culvert diversion, etc. according to the type of diversion and discharge buildings. Sun Wangcong (1) Nullah diversion.

This construction diversion method is generally suitable for the terrain with a gentle bank slope or a bank with a wide platform, pass or paleochannel. The nullah has the advantages of simple construction and suitable for large-scale mechanical construction; It is conducive to accelerating the construction progress and shortening the construction period. Then the cherry limb (2) tunnel diversion.

Tunnel diversion is to excavate the tunnel on the river bank, build a cofferdam in the upstream and downstream of the foundation pit, and block the riverbed to form a foundation pit at one time to protect the dry land construction of the main building. This diversion method is suitable for mountain rivers with narrow valleys, steep terrain on both sides, and solid rocks. (3) Culvert diversion.

Culvert diversion is the use of culvert pipe for diversion. It is suitable for rivers with small diversion flow or only for diversion during dry seasons. It is generally used in the construction of earth dams, rockfill dams and other projects.