Ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season

Abstract

The present invention discloses an ecological diversion tunnel structure and an operation method thereof that can be used for super-high rockfill dams during the main flood season, and belongs to the field of water conservancy and hydropower engineering, and is used to solve the problem that ecological water supply tunnels cannot participate in flood season diversion. The ecological water supply tunnel structure includes an ecological water supply tunnel, which is connected to the upstream river channel and the downstream river channel of the rockfill dam body respectively, and the ecological water supply tunnel includes a gate chamber front tunnel section, a gate chamber section and a gate chamber rear tunnel section, and a gate chamber is arranged in the gate chamber section; and also includes a bypass tunnel, the inlet end of the bypass tunnel is connected to the gate chamber front tunnel section, and the outlet end of the bypass tunnel is connected to the gate chamber rear tunnel section. The present invention can bypass the gate chamber section of the ecological water supply tunnel through the bypass tunnel, so that it has the function of diversion during the flood season, expands the function of the ecological water supply tunnel, and achieves the purpose of one tunnel for multiple uses.

Description

Technical Field

[0001] The invention relates to the field of water conservancy and hydropower engineering, and in particular to an ecological diversion tunnel structure and an operation method thereof that can be used for super-high rockfill dams during the main flood season. Background Art

[0002] At present, many 300m-class extra-high rockfill dam hydropower projects are being built and planned in southwest my country, such as Shuangjiangkou 312m, Lianghekou 295m, Rumei 315m, etc. These extra-high rockfill dams are located in high mountain valleys with steep slopes on both sides of the riverbed. The construction diversion adopts the tunnel diversion scheme of digging corresponding diversion tunnels in the mountain, so that the upstream river channel is diverted to flow into the downstream river channel through the diversion tunnel.

[0003] With the continuous improvement of environmental protection requirements for water conservancy and hydropower projects, the issue of ecological flow discharge from reservoir projects has become a focus of attention for environmental protection authorities. Ultra-high rockfill dams are large in scale, have a long construction period, are difficult to close and store water, and involve many complex factors. The design of ecological diversion tunnels has the following key issues that need to be resolved: (1) Due to environmental protection requirements, downstream flow is not allowed to be interrupted, and the discharge flow must meet the requirements of ecological water supply flow; (2) During the water storage period, the water level rise rate needs to be controlled to ensure the safety of the earth-rock dam body. Under this circumstance, special ecological diversion tunnels have begun to be set up for ecological water supply.

[0004] At the same time, the flow rate of hydropower projects in western China varies significantly between the main flood season and the dry season. The flood flow rate in the main flood season is relatively large. During the operation of the power station, it is necessary to ensure the safety of the project construction during the main flood season. However, in recent years, heavy rains have occurred frequently in the dam site area of ​​the hydropower station, and extreme floods have occurred many times, which has brought great safety hazards to the construction of high dams. For example, in 2017, the continuous rainfall in the area where the Shuangjiangkou Hydropower Station is located exceeded 25 mm in nearly 24 hours, and the maximum flow of the No. 1 diversion tunnel reached 3710 cubic meters / second, which refreshed the maximum peak record of the project since the survey and design work began. However, due to the high water level during the main flood season of construction, the tunnel body is in a pressurized flow state, and the arc gate hinge at the gate chamber of the ecological diversion tunnel will be destroyed by high-speed and high-pressure water flow. The gate chamber of the ecological diversion tunnel cannot withstand the impact of water flow during the flood season, making the ecological diversion tunnel unable to participate in the flood season diversion. Therefore, how to expand the function of the ecological diversion tunnel so that it can divert water during the main flood season has become the focus of attention in the hydropower engineering industry. Summary of the invention

[0005] The technical problem solved by the present invention is that the ecological diversion tunnel cannot participate in the flood diversion during the main flood season of the ultra-high rockfill dam construction, thereby expanding the function of the ecological diversion tunnel itself and achieving the purpose of multiple uses of one tunnel.

[0006] The technical solution adopted by the present invention to solve its technical problems is: an ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season, including an ecological diversion tunnel, which respectively connects the upstream river channel and the downstream river channel of the rockfill dam body, and the ecological diversion tunnel includes a front tunnel section of a lock chamber, a lock chamber section and a rear tunnel section of a lock chamber, and a lock chamber is arranged in the lock chamber section; it also includes a bypass tunnel, the inlet end of the bypass tunnel is connected to the front tunnel section of the lock chamber, and the outlet end of the bypass tunnel is connected to the rear tunnel section of the lock chamber.

[0007] Furthermore, a plane gate and a curved gate with adjustable opening are arranged in the gate chamber, and the plane gate is located at the upstream side of the curved gate.

[0008] Furthermore, the diameter of the bypass tunnel is consistent with the diameter of the ecological diversion tunnel.

[0009] Furthermore, a vertical shaft is provided extending upward from the top of the lock chamber, and the top of the vertical shaft passes through the ground surface. The elevation of the top of the vertical shaft is 1m higher than the flood level of 20 years during the sealing period of the ecological diversion tunnel.

[0010] Furthermore, a blocking area is reserved in the bypass hole for setting a blocking plug.

[0011] Furthermore, a sealing plug is arranged in the bypass hole, and the sealing plug includes an inlet end plug and an outlet end plug.

[0012] In addition, the present invention also provides an operation method of the above ecological diversion tunnel structure that can be used for super high rockfill dam during the main flood season, comprising the above ecological diversion tunnel structure that can be used for super high rockfill dam during the main flood season, and also comprising an initial diversion tunnel, the initial diversion tunnel respectively connecting the upstream river channel and the downstream river channel of the rockfill dam body; the operation method comprises the following steps:

[0013] a. During the main flood season of the ultra-high rockfill dam construction, the ecological diversion tunnel is in a flood-proof state: in this state, the gates installed in the gate chamber of the ecological diversion tunnel are closed, so that the water flows through the bypass tunnel. During this period, the flood-proof diversion buildings are the initial diversion tunnel and the ecological diversion tunnel;

[0014] b. During the dry season before the initial diversion tunnel is closed and water is stored, the upstream water flow is generally small. First, the ecological diversion tunnel inlet interception construction is carried out. Since the flow during the dry season is generally small, the inlet interception construction is also relatively easy, thus ensuring the dry land conditions in the ecological diversion tunnel. Then, the bypass tunnel is sealed and plugged. After the sealing and plugging construction is completed, the bypass tunnel is completely blocked;

[0015] c. During the water storage period after the initial diversion tunnel is closed, the ecological diversion tunnel is in a state of downstream ecological flow: the gates set in the gate chamber of the ecological diversion tunnel are opened, and water flows through the ecological diversion tunnel;

[0016] d. After the water level rises to the target level, close the gate installed in the gate chamber of the ecological diversion tunnel and carry out permanent plugging construction in the ecological diversion tunnel.

[0017] Furthermore, a plane gate and an arc gate with adjustable opening are arranged in the gate chamber at the same time, and the plane gate is located on the upstream side of the arc gate; in steps a and d, the ecological diversion tunnel is closed by the plane gate; in step c, the plane gate is fully opened, and the downstream flow of the ecological diversion tunnel is adjusted by using the arc gate while meeting the requirements of the downstream ecological water supply flow and the water level rising speed.

[0018] Furthermore, the inlet floor elevation of the initial diversion tunnel is consistent with the inlet floor elevation of the ecological diversion tunnel.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention cleverly sets a bypass tunnel, which bypasses the lock chamber section of the ecological diversion tunnel, so that it can divert water during the main flood season, expand the function of the ecological diversion tunnel, and achieve the purpose of one tunnel for multiple uses. The present invention has a simple structural arrangement and is easy to construct. The use of the ecological diversion tunnel to divert water during the flood season can improve the flood standard of the high dam project, reduce safety risks, reduce the design elevation of the upstream cofferdam, and alleviate the construction period pressure of the dam body in the middle and late stages, which has good economic and social benefits.

[0021] 2. The present invention uses a bypass tunnel and a flat gate arranged in the gate chamber, making full use of the high reliability of the flat gate in blocking water. When the ecological diversion tunnel is in the flood season, the flat gate is closed to allow the main flood season water flow to flow through the bypass tunnel, effectively avoiding the problem of the main flood season water flow impacting and damaging the gate chamber, and solving the problem that the gate chamber of the ecological diversion tunnel is damaged by the main flood season water flow impact and cannot be safely used during the flood season.

[0022] 3. The present invention uses a flat gate arranged in the gate chamber to complete the plugging of the bypass tunnel during a dry season before the ecological diversion tunnel is closed for water storage, thereby rendering the bypass tunnel ineffective; then the ecological flow can be controlled and discharged downstream through the gate in the gate chamber of the ecological diversion tunnel, and the discharge flow can be controlled by the arc gate to meet the corresponding requirements for rising water storage level and ecological flow required for environmental protection; finally, after the water storage level rises to the target water level, the flat gate is lowered to ensure dry land construction conditions for permanent plugging of the ecological diversion tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a plan view of an ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season.

[0024] Figure 2 for Figure 1 Schematic diagram of the enlarged area A in the middle.

[0025] Figure 3 This is the longitudinal section of the ecological diversion tunnel.

[0026] Marked in the figure are: ecological diversion tunnel 1, gate chamber front tunnel section 11, gate chamber section 12, gate chamber rear tunnel section 13, rockfill dam body 2, gate chamber 3, bypass tunnel 4, inlet end plug 41, outlet end plug 42, plane gate 5, radial gate 6, vertical shaft 7, top elevation of the vertical shaft 8, 20-year flood water level during the ecological diversion tunnel sealing period 9, initial diversion tunnel 10, and later diversion tunnel 101. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0028] like Figures 1 to 3 As shown, an ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season includes an ecological diversion tunnel 1, which is connected to the upstream river channel and the downstream river channel of the rockfill dam body 2 respectively. The ecological diversion tunnel 1 includes a lock chamber front tunnel section 11, a lock chamber section 12 and a lock chamber rear tunnel section 13, and a lock chamber 3 is arranged in the lock chamber section 12; it also includes a bypass tunnel 4, the inlet end of the bypass tunnel 4 is connected to the lock chamber front tunnel section 11, and the outlet end of the bypass tunnel 4 is connected to the lock chamber rear tunnel section 13.

[0029] The ultra-high rockfill dam in the present invention refers to a rockfill dam with a dam body 2 having a height exceeding 200 meters.

[0030] The ecological diversion tunnel 1 in the present invention refers to a tunnel mainly used to release ecological flow to the downstream during the dam construction process to meet the downstream ecological flow demand.

[0031] The bypass hole 4 in the present invention is used to bypass the lock chamber section 12 to connect the lock chamber front hole section 11 and the lock chamber rear hole section 13, and form a bypass channel for discharge. Since the bypass channel does not need to pass through the lock chamber section 12, when the bypass channel is used to discharge the main flood season water flow, it can avoid the main flood season water flow from causing impact damage to the lock chamber 3 in the lock chamber section 12. Therefore, the ecological diversion hole 1 connected by the bypass hole 4 can be used for main flood season diversion. Of course, during the construction of the dam, an initial diversion hole 10 is generally provided specifically for discharging river water. Therefore, during the main flood season, the present invention can simultaneously use the ecological diversion hole 1 and the initial diversion hole 10 connected by the bypass hole 4 to jointly carry out the main flood season diversion. This can not only improve the flood control standard of the dam project and reduce safety risks, but also reduce the design elevation of the upstream cofferdam, relieve the construction period pressure of the dam body in the middle and late stages, and has good economic and social benefits.

[0032] In addition, in order to ensure the flow capacity of the bypass hole 4, the hole diameter of the bypass hole 4 in the present invention is preferably consistent with the hole diameter of the ecological diversion hole 1.

[0033] In addition, the ecological diversion tunnel 1 in the present invention needs to be able to discharge ecological flow after the initial diversion tunnel 10 is closed. Therefore, the bypass tunnel 4 can be blocked before the ecological flow is discharged. During the discharge of the ecological flow, the flow can be regulated and controlled through the gate in the lock chamber 3. Accordingly, a blocking area is reserved in the bypass tunnel 4 for setting a blocking plug to carry out the construction of the blocking plug. Figure 2 As shown, a sealing plug is provided in the bypass hole 4 , and the sealing plug includes an inlet end plug 41 and an outlet end plug 42 .

[0034] More specifically, the present invention further provides a plane gate 5 and an adjustable opening arc gate 6 in the gate chamber 3, and the plane gate 5 is located on the upstream side of the arc gate 6. In this way, the plane gate 5 can be used to completely block the gate chamber to ensure the blocking effect; the arc gate 6 is used to adjust and control the discharge flow to achieve the purpose of discharge control, which is conducive to the control of the discharge flow and the control of the rising speed of the water level.

[0035] In addition, the present invention further provides a vertical shaft 7 extending upward from the top of the lock chamber 3, the top of the vertical shaft 7 passes through the ground surface, and the top elevation 8 of the vertical shaft 7 is 1 meter higher than the flood water level 9 of a return period of 20 years during the plugging period of the ecological diversion tunnel. The lock chamber 3 can be easily entered through the vertical shaft 7, and the top elevation 8 of the vertical shaft 7 is 1 meter higher than the flood water level 9 of a return period of 20 years during the plugging period of the ecological diversion tunnel, ensuring that the water level upstream of the dam body during this period will not submerge the top elevation 8 of the vertical shaft 7, thereby avoiding submerging the lock chamber 3.

[0036] In addition, the present invention also provides an operation method of an ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season, comprising the above-mentioned ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season, and also comprising an initial diversion tunnel 10, the initial diversion tunnel 10 respectively connecting the upstream river channel and the downstream river channel of the rockfill dam body 2; the operation method comprises the following steps:

[0037] a. During the main flood season when the initial diversion tunnel 10 is in the diversion operation period, the ecological diversion tunnel 1 is in the flood control state: in this state, the gates arranged in the gate chamber 3 of the ecological diversion tunnel 1 are closed, so that the water flows through the bypass tunnel 4. During this period, the flood control diversion buildings are the initial diversion tunnel 10 and the ecological diversion tunnel 1;

[0038] b. During the dry season before the initial diversion tunnel 10 is closed and water is stored, the upstream water flow is generally small. First, the ecological diversion tunnel 1 inlet interception construction is carried out. Since the flow rate during the dry season is generally small, the inlet interception construction is also relatively easy, thus ensuring the dry land conditions in the ecological diversion tunnel 1. Then, the bypass tunnel 4 is plugged and blocked. After the plugging construction is completed, the bypass tunnel 4 is completely blocked;

[0039] c. During the water storage period after the initial diversion tunnel 10 is closed, the ecological diversion tunnel 1 is in a downward discharge ecological flow state: the gate set in the gate chamber 3 of the ecological diversion tunnel 1 is opened, and the water flows through the ecological diversion tunnel 1;

[0040] d. After the water level rises to the target water level, close the gate installed in the gate chamber 3 of the ecological diversion tunnel 1, and carry out permanent plugging construction in the ecological diversion tunnel 1.

[0041] Among them, in step a, the front tunnel section 11 and the rear tunnel section 13 of the ecological diversion tunnel 1 are connected through the bypass tunnel 4, so that the ecological diversion tunnel 1 can be used for flood diversion, and during the flood diversion, the water flows through the bypass tunnel 4 instead of passing through the lock chamber 3 in the lock chamber section 12, thereby effectively avoiding impact damage to the lock chamber 3 during the flood diversion.

[0042] In step b, the initial diversion tunnel 10 is in the last dry period of the diversion operation period, and a plugging plug is constructed in the bypass tunnel 4 to block the bypass tunnel 4, and then the bypass tunnel 4 becomes ineffective. Thereafter, the ecological diversion tunnel 1 connected by the front tunnel section 11 of the lock chamber, the lock chamber section 12 and the rear tunnel section 13 of the lock chamber supplies ecological water downstream. The flow rate of the ecological water supply can be regulated by the gate in the lock chamber 3, and can be specifically controlled comprehensively according to the requirements of the downstream ecological flow rate and the speed of the water level rise.

[0043] Of course, the initial diversion tunnel 10 is preferably sealed by closing the gate during the dry season, so the initial diversion tunnel 10 is sealed by closing the gate during the last dry season in the diversion operation period.

[0044] After the water level rises to the target water level, the gates installed in the gate chamber 3 of the ecological diversion tunnel 1 are closed, and permanent plugging construction is carried out in the ecological diversion tunnel 1. After the ecological diversion tunnel 1 is blocked, the ecological diversion tunnel 1 becomes ineffective. The above-mentioned target water level should be sufficient to allow the ecological flow to be discharged downstream through other tunnels. For example, in the case where a later diversion tunnel 101 is provided, the elevation of the later diversion tunnel 101 is higher than that of the initial diversion tunnel 10 and the ecological diversion tunnel 1. When the water level reaches a point where the ecological flow can be discharged downstream through the later diversion tunnel 101, the ecological diversion tunnel 1 can be blocked, thereby avoiding the interruption of the ecological flow discharged downstream.

[0045] In addition, in order to facilitate the gate control of the discharge flow in the lock chamber 3, it is preferred to simultaneously set a plane gate 5 and a radial gate 6 with adjustable opening in the lock chamber 3, and the plane gate 5 is located on the upstream side of the radial gate 6. The plane gate 5 is used to close the gate when complete blocking is required, and the radial gate 6 can be used to adjust and control the ecological flow when the discharge is required; specifically, both step a and step d close the ecological diversion tunnel 1 by closing the plane gate 5; in step c, the plane gate 5 is fully opened, and the radial gate 6 is used to adjust the downstream flow of the ecological diversion tunnel 1 when the requirements for the downstream ecological water supply flow and the requirements for the water level rise speed are met.

[0046] In addition, after the initial diversion tunnel 10 is closed, in order to be able to continuously release ecological flow downstream through the ecological diversion tunnel 1, the present invention preferably controls the inlet bottom plate elevation of the initial diversion tunnel 10 to be consistent with the inlet bottom plate elevation of the ecological diversion tunnel 1.

Claims

1. An operation method of an ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season, characterized in that: The invention comprises an ecological diversion tunnel structure and an initial diversion tunnel (10) which can be used for super-high rockfill dam during the main flood season. The ecological diversion tunnel structure which can be used for super-high rockfill dam during the main flood season comprises an ecological diversion tunnel (1) and a bypass tunnel (4). The ecological diversion tunnel (1) is connected to the upstream river channel and the downstream river channel of the rockfill dam body (2) respectively. The ecological diversion tunnel (1) comprises a lock chamber front tunnel section (11), a lock chamber section (12) and a lock chamber rear tunnel section (13). The lock chamber section (12) is provided with a lock chamber (3). The inlet end of the bypass tunnel (4) is connected to the lock chamber front tunnel section (11), and the outlet end of the bypass tunnel (4) is connected to the lock chamber rear tunnel section (13). A blocking area capable of setting a blocking plug is reserved in the bypass tunnel (4). The initial diversion tunnel (10) is connected to the upstream river channel and the downstream river channel of the rockfill dam body (2) respectively. The operation method comprises the following steps: a. During the flood season when the initial diversion tunnel (10) is in the diversion operation period, the ecological diversion tunnel (1) is in a flood control state: in this state, the gate provided in the gate chamber (3) of the ecological diversion tunnel (1) is closed, so that the water flows through the bypass tunnel (4). During this period, the flood control diversion structures are the initial diversion tunnel (10) and the ecological diversion tunnel (1); b. During the dry season before the initial diversion tunnel (10) is closed to store water, the bypass tunnel (4) is plugged and blocked. After the plugging and blocking construction is completed, the bypass tunnel (4) is completely blocked; c. During the water storage period after the initial diversion tunnel (10) is closed by the sluice gate, the ecological diversion tunnel (1) is in a state of downstream ecological flow: the gate provided in the gate chamber (3) of the ecological diversion tunnel (1) is opened, and water flows through the ecological diversion tunnel (1); d. After the water level rises to the target water level, the gate provided in the gate chamber (3) of the ecological diversion tunnel (1) is closed, and permanent plugging construction is carried out in the ecological diversion tunnel (1).

2. The method for operating the ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season as claimed in claim 1, characterized in that: A plane gate (5) and a curved gate (6) with an adjustable opening are arranged in the gate chamber (3), and the plane gate (5) is located on the upstream side of the curved gate (6).

3. The method for operating the ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season as claimed in claim 1, characterized in that: The diameter of the bypass hole (4) is consistent with the diameter of the ecological diversion hole (1).

4. The method for operating the ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season as claimed in claim 1 is characterized in that: A vertical shaft (7) is provided on the top of the lock chamber (3) extending upward, the top of the vertical shaft (7) passing through the ground surface, and the top elevation (8) of the vertical shaft (7) is 1 meter higher than the flood water level (9) of 20 years during the sealing period of the ecological diversion tunnel.

5. The method for operating the ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season as claimed in claim 1 is characterized in that: The sealing plug in the bypass hole (4) comprises an inlet end plug (41) and an outlet end plug (42).

6. The method for operating the ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season as claimed in any one of claims 1 to 5, characterized in that: A plane gate (5) and an arc gate (6) capable of adjusting the opening are arranged in the gate chamber (3), and the plane gate (5) is located on the upstream side of the arc gate (6); in both step a and step d, the ecological diversion tunnel (1) is closed by the plane gate (5); in step c, the plane gate (5) is fully opened, and the downstream flow of the ecological diversion tunnel (1) is adjusted by the arc gate (6) while meeting the requirements of the downstream ecological water supply flow rate and the requirements of the water storage level rising speed.

7. The method for operating the ecological diversion tunnel structure that can be used for super-high rockfill dams during the main flood season as claimed in any one of claims 1 to 5, characterized in that: The inlet floor elevation of the initial diversion tunnel (10) is consistent with the inlet floor elevation of the ecological diversion tunnel (1).

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