CN106284240A - A kind of power station is in construction time downstream interim water-supply structure and method - Google Patents

Abstract

The invention belongs to the technical field of temporary water supply for hydraulic structures, in particular to a temporary water supply structure downstream of a hydropower station during the construction period. It includes a diversion tunnel located on the mountain and used for temporary flood discharge. The diversion tunnel is provided with a diversion tunnel entrance, and a gate for controlling water flow is provided at the entrance of the diversion tunnel. There is a construction branch tunnel connected with the diversion tunnel, and the construction branch tunnel is used as a channel for the construction of the diversion tunnel body in the early stage, and as a bypass tunnel for supplying water to the downstream in the later stage. The invention converts the construction branch hole of the diversion tunnel into a bypass hole, and does not need to set up a water discharge hole, which reduces project investment, saves cost, reduces investment, saves construction period, and has significant technical and economic benefits.

Description

A structure and method for temporarily supplying water downstream of a hydropower station during construction

technical field

The invention belongs to the technical field of temporary water supply for hydraulic structures, in particular to a structure and method for temporarily supplying water downstream of a hydropower station during construction.

Background technique

With the development technology of large-scale hydropower stations in my country becoming more and more mature, it is necessary to fully consider the impact of ecological flow on the downstream environment in the design of power stations. For the design of water conservancy and hydropower projects of high dams and large reservoirs, the temporary flood discharge structures that discharge flood downstream during the construction period need to be completely blocked after the completion of the project, but are affected by the water retaining and discharge control of the flat doors and arc doors of the hydraulic flood discharge structures. Due to the limitation of capacity, during the water storage period of the project gate, temporary water discharge holes are usually set up in layers on the dam body or mountain body, forming the current commonly used method of relay sealing temporary holes. Some projects do not even consider the impact of ecological flow on the downstream environment. During the impoundment period of the project, there will be a phenomenon of deflow in the downstream section for a period of time, which will have a great impact on the ecological environment of the river channel in a short period of time. For projects that use layered holes to supply water to the downstream, subject to the limit of the water retaining pressure of the gate, holes must be added, thereby increasing the amount and cost of the project, and affecting the construction period of the project.

Contents of the invention

In order to overcome the problems of high risk of water supply to the downstream of the high dam and large reservoir of the large-scale hydropower station during the water storage of the lower gate, the high cost and the impact on the construction period, the purpose of the present invention is to provide a temporary water supply structure and method for the downstream of the hydropower station during the construction period.

In order to realize the above-mentioned technical purpose, the present invention adopts following technical scheme to realize:

A temporary water supply structure downstream of a hydropower station during the construction period, including a diversion tunnel located on the mountain and used for temporary flood discharge, the diversion tunnel is provided with a diversion tunnel entrance, and the diversion tunnel entrance is provided with a water flow control channel. The upstream of the entrance of the diversion tunnel is provided with a construction branch tunnel connected with the diversion tunnel. The construction branch tunnel is a channel for the construction of the diversion tunnel body in the early stage and a bypass hole for supplying water to the downstream in the later stage.

Preferably, a control sluice chamber is provided in the bypass hole close to its outlet, and a cone valve for controlling the upstream water level and the downstream water discharge is arranged in the control sluice chamber.

Preferably, an energy dissipation chamber for consuming water flow energy is also provided in the bypass hole near its outlet, and the energy dissipation chamber is located behind the control lock chamber.

Preferably, the energy dissipation chamber is oval.

Preferably, the energy dissipation chamber has a length of 7-20m, a width of 1-10m, and a width of 1-10m.

Preferably, the control lock chamber is also connected with an external control channel, one end of the external control channel leads to the control lock chamber, and the other end leads to the bottom surface. Specifically, the external control channel is a shaft or an inclined shaft.

Another object of the present invention is to provide a method for temporarily supplying water downstream of a hydropower station during the construction period, comprising the following steps:

Step 1, the engineering reservoir completes water storage;

Step 2. When the upstream water level exceeds the inlet elevation of the cone valve of the bypass tunnel, the inlet gate of the diversion tunnel

gate under the gate;

Step 3, under the control of the cone valve, supply water to the downstream;

Step 4. After the water level exceeds the inlet elevation of the hydraulic permanent flood discharge structure, close the cone valve;

Step 5, the diversion hole starts to be blocked, and the water supply is completed after the sealing is completed.

Beneficial effects of the present invention:

The invention converts the construction branch hole of the diversion tunnel into a bypass hole, and does not need to set up a water discharge hole, which reduces project investment, saves cost, reduces investment, saves construction period, and has significant technical and economic benefits.

Description of drawings

Fig. 1 is the plane layout schematic diagram of temporary water supply structure of the present invention;

Fig. 2 is the sectional structure schematic diagram of diversion tunnel of the present invention;

Fig. 3 is a schematic cross-sectional structure diagram of the cooperation between the bypass hole and the shaft.

In the figure, 1-entrance of diversion tunnel; 2-bypass tunnel; 3-shaft; 4-cone valve; 5-diversion tunnel; 6-energy dissipation chamber;

detailed description

The present invention will be further described below in conjunction with accompanying drawing:

Example 1

In order to overcome the problems of high risk of water supply to the downstream of the high dam and large reservoir of the large-scale hydropower station during the storage period of the gate, the problem of high cost and impact on the construction period, this embodiment provides a temporary water supply to the downstream of the hydropower station during the construction period as shown in Figures 1 to 3 The structure includes a diversion tunnel 5 located on the mountain body 7 and used for temporary flood discharge, the diversion tunnel 5 is provided with a diversion tunnel entrance 1, and a gate for controlling water flow is provided at the diversion tunnel entrance 1. The upstream of the diversion tunnel entrance 1 is provided with a construction branch tunnel connected with the diversion tunnel 5. The construction branch tunnel is used as a channel for the construction of the diversion tunnel 5 in the early stage and as a bypass tunnel 2 for supplying water to the downstream in the later stage.

Wherein, the early stage and the late stage are calculated by the completion time of the construction of the diversion tunnel 5, the time when the construction of the diversion tunnel 5 is not completed is the early stage, and the time after the construction of the diversion tunnel 5 is completed is the late stage.

In the present invention, the construction branch of diversion tunnel 5 is converted into bypass tunnel 2, and there is no need to set up water discharge holes, which reduces engineering investment, saves costs, reduces investment, saves construction period, and has significant technical and economic benefits.

Example 2

On the basis of Embodiment 1, as shown in Figure 3, a control lock chamber 8 is provided in the bypass hole 2 close to its outlet, and the control lock chamber 8 is provided with a cone valve for controlling the upstream water level and the amount of water discharged. 4. The cone valve 4 has the advantages of high energy dissipation rate, simple construction, small space occupation and low maintenance requirements. The poppet valve 4 can be a common poppet valve in the market, which will not be described in detail here.

An energy dissipating chamber 6 is also provided near the outlet of the bypass hole 2, the energy dissipating chamber 6 is located behind the control lock chamber 8, and the energy dissipating chamber 6 is used to consume the energy released by the cone valve 4. The energy of high-speed water flow. The present invention adopts the structure of the cone valve 4 and the energy dissipation chamber 6 for continuous discharge flow control, adapts to high water head and flows at all levels, and can solve the problems of high water head, high flow rate, long continuous operation time, downstream flood discharge and energy dissipation.

The energy dissipating chamber 6 is elliptical, and the elliptical shape has better conditions for water flow, and limits the direction of water flow to form a hedge to dissipate water energy. The energy dissipation chamber 6 has a length of 7-20m, a width of 1-10m, and a width of 1-10m, within which a better energy dissipation effect can be achieved.

The control lock chamber 8 is also connected with an external control channel 3, one end of the external control channel 3 leads to the control lock chamber 8, and the other end leads to the bottom surface, and the control lock chamber 8 and the external connection are realized through the external control channel 3. Contact, convenient maintenance and observation of cone valve 4. Specifically, the external control channel is a vertical shaft or an inclined shaft, and the selection of the vertical shaft or the inclined shaft is determined according to geological conditions.

Example 3

In order to overcome the defects in the prior art that the wetting line of the existing dam body is raised and cannot be repaired, which seriously affects the safety of the dam body, the present invention provides a method for temporarily supplying water downstream of a hydropower station during the construction period, which includes the following steps:

Step 1, the engineering reservoir completes water storage;

Step 2. When the upstream water level exceeds the inlet elevation of the cone valve 4 of the bypass tunnel 2, the gate of the diversion tunnel entrance 1 is lowered;

Step 3, under the control of the cone valve 4, supply water downstream;

Step 4, after the water level exceeds the inlet elevation of the hydraulic permanent flood discharge structure, close the cone valve 4;

Step 5, the diversion tunnel 5 starts to be blocked, and the water supply is completed after the sealing is completed.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention also intends to include these modifications and variations.

Claims (8)

1. A temporary water supply structure downstream of a hydropower station during the construction period, characterized in that: it includes a diversion tunnel (5) that is located on the mountain body (7) and is used for temporary flood discharge, and the diversion tunnel (5) is provided with a diversion tunnel. Flow tunnel entrance (1), described diversion tunnel entrance (1) place is provided with the gate of water flow control, and the upstream of described diversion tunnel entrance (1) is provided with a construction branch tunnel that communicates with diversion tunnel (5), The construction branch tunnel is used as a channel for the construction of the diversion tunnel (5) in the early stage, and is used as a bypass tunnel (2) for water supply to the downstream in the later stage. 2. The temporary water supply structure downstream of the hydropower station during the construction period according to claim 1, characterized in that: a control lock chamber (8) is provided in the bypass hole (2) near its exit, and the control lock chamber (8) is equipped with a cone valve (4) for controlling the upstream water level and the amount of water discharged. 3. The temporary water supply structure downstream of the hydropower station according to claim 2, characterized in that: an energy dissipation chamber (6) that consumes water flow energy is also provided in the bypass hole (2) near its exit, The energy dissipation chamber (6) is located behind the control lock chamber (8). 4. The temporary downstream water supply structure of the hydropower station during the construction period according to claim 3, characterized in that: the energy dissipation chamber (6) is oval. 5. The temporary downstream water supply structure of the hydropower station during the construction period according to claim 3, characterized in that: the energy dissipation chamber (6) has a length of 7-20m, a width of 1-10m, and a width of 1-10m. 6. The temporary water supply structure downstream of the hydropower station during the construction period according to claim 3, characterized in that: the control lock chamber (8) is also connected with an external control channel (3), and one end of the external control channel (3) It leads to the control lock chamber (8), and the other end leads to the bottom surface. 7. The temporary downstream water supply structure of the hydropower station during the construction period according to claim 3, characterized in that: the external control channel is a vertical shaft or an inclined shaft. 8. A method for temporarily supplying water downstream of a hydropower station during the construction period, characterized in that: comprising the following steps: Step 1, the engineering reservoir completes water storage; Step 2, when the upstream water level exceeds the entrance elevation of the cone valve (4) of the bypass tunnel (2), the gate of the diversion tunnel entrance (1) is lowered; Step 3, under the control of the cone valve (4), supply water to the downstream; Step 4, after the water level exceeds the inlet elevation of the hydraulic permanent flood discharge structure, close the cone valve (4); Step 5, the diversion hole (5) starts to be blocked, and the water supply is completed after the sealing is completed.