Structure of diversion tunnels for ultra-high rockfill dam

Abstract

The present invention discloses a structure of a diversion tunnel group of an ultra-high rockfill dam and a method for closing the gates and blocking the same, and belongs to the technical field of water conservancy and hydropower engineering. The present invention ingeniously optimizes the closing and blocking procedures, and adopts multi-stage controlled discharge and water storage through tunnels at various levels and corresponding arc gates, so as to realize the continuous flow of water supply during the closing and blocking of diversion tunnels at various levels. At the same time, through the controlled discharge and water storage at various stages, when the water storage reaches a certain height, the water storage rising speed can be effectively controlled, and the requirements for the water storage rising speed during the water storage process of ultra-high dams at various stages can be met; in addition, temporary plugs are set in the initial and middle diversion tunnels to block water, replacing the situation of water blocking by flat gates in traditional thinking, which greatly reduces the water head requirements for the blocking gates of the initial and middle diversion tunnels, improves the safety of gate water blocking and structural pressure resistance, and can significantly reduce the scale of the blocking gate and hoist system, saving engineering investment.

Description

Technical Field

[0001] The invention relates to the field of water conservancy and hydropower engineering, and in particular to a diversion tunnel group structure of an ultra-high rockfill dam and a sluice-lowering and blocking method thereof. Background Art

[0002] At present, my country's southwest region is constructing and planning a number of 300m-class extra-high rockfill dam hydropower projects, such as Changheba 240, Shuangjiangkou 312m, Lianghekou 295m, Rumei 315m, Maerdang 210m, etc. These extra-high rockfill dams are located in high mountain canyons, with steep slopes on both sides of the riverbed. The construction diversion adopts a tunnel diversion scheme of excavating corresponding diversion tunnels in the mountain, so that the upstream river channel is diverted through the diversion tunnel to flow into the downstream river channel. Due to the high dam body, in order to meet the requirements of flood control and flood control at different stages, the diversion tunnels need to be arranged in layers to form a multi-layer diversion tunnel group with a certain height difference, which is generally divided into lower elevation initial and middle diversion tunnels and higher elevation later diversion tunnels. After completing the flood discharge task, these diversion tunnel groups must be closed by closing the gates to meet the requirements of reservoir water storage and power generation. However, due to the high dam body of the ultra-high rockfill dam and the increasing environmental protection requirements for hydropower projects, there are many difficulties in closing the gates of the multi-layer diversion tunnel group:

[0003] (1) During the construction period of the ultra-high rockfill dam, the water can only be discharged through diversion tunnels set up in the mountain. The height difference of each diversion tunnel is often large. During the closure period, the ecological water supply requirements of the downstream river must be met. How to ensure the connection and continuous water supply of each diversion tunnel during the closure process has become a key issue that needs to be solved during the water storage process;

[0004] (2) In the initial stage of water storage in ultra-high rockfill dams, due to the structural safety requirements of the dam body itself, it is necessary to control the water storage rising speed after reaching a certain height;

[0005] (3) The ultra-high rockfill dam is very high, and the water head during the diversion tunnel plugging period is very high, which poses a great risk to the structural safety.

[0006] (4) The diversion tunnel plugging gate has a high water head and a large opening and closing capacity. The plugging gate and the opening and closing machine are large in scale and require high investment. Summary of the invention

[0007] In view of the above technical problems, the present invention provides a new diversion tunnel group structure of an ultra-high rockfill dam and a gate lowering and blocking method thereof.

[0008] The technical solution adopted by the present invention to solve the technical problem is: the diversion tunnel group structure of the ultra-high rockfill dam includes an initial and middle diversion tunnel, an ecological diversion tunnel, a late No. 1 diversion tunnel, a late No. 2 diversion tunnel, a venting tunnel and a deep hole flood discharge tunnel; the initial and middle diversion tunnel is arranged at the lowest elevation, the ecological diversion tunnel and the initial and middle diversion tunnel are arranged at the same elevation, the later No. 1 diversion tunnel is arranged at an elevation higher than the initial and middle diversion tunnel and lower than the later No. 2 diversion tunnel; the inlet section of the initial and middle diversion tunnel is provided with a first bank tower lock chamber, and the first bank tower lock chamber is provided with a first flat plate lock The initial and intermediate diversion tunnel section is provided with a first permanent plug, and a temporary plug is provided immediately upstream of the first permanent plug; the upstream side of the ecological diversion tunnel section is provided with a shaft lock chamber, the shaft lock chamber is provided with a first arc gate, and the downstream side of the ecological diversion tunnel section is provided with a second permanent plug; the inlet sections of the later No. 1 diversion tunnel and the later No. 2 diversion tunnel are respectively provided with second bank tower lock chambers, the second bank tower lock chambers are provided with second flat gates and second arc gates, and the downstream sides of the tunnel sections of the later No. 1 diversion tunnel and the later No. 2 diversion tunnel are respectively provided with third permanent plugs.

[0009] The present invention also provides a method for closing a gate and plugging a diversion tunnel group of an ultra-high rockfill dam, wherein the method forms the above-mentioned diversion tunnel group structure of the ultra-high rockfill dam; the year when the diversion tunnel group is closed and plugged is taken as the first year, and the method comprises the following steps:

[0010] a. After the flood season of the first year, the first flat gate in the first bank tower gate chamber of the initial and intermediate diversion tunnel is first lowered to block water, create dry land construction conditions for the temporary plugging of the initial and intermediate diversion tunnel, and carry out temporary plugging construction; after the first flat gate is lowered, the first arc gate of the ecological diversion tunnel is fully opened to discharge the upstream water through the ecological diversion tunnel to ensure that the downstream water flow is continuous. Assuming that the upstream water level at this time is H1, the designed water blocking capacity of the first flat gate in the first bank tower gate chamber of the initial and intermediate diversion tunnel can meet the blocking capacity of H1;

[0011] b. After the temporary plug in the primary and secondary diversion tunnel is completed and meets the water-blocking conditions, open and retract the first flat gate to allow water to flow into the primary and secondary diversion tunnel. At this time, the temporary plug blocks the water, creating dry land construction conditions for the first permanent plug in the primary and secondary diversion tunnel, and the construction of the first permanent plug is carried out;

[0012] c. After the first flat gate is opened and recovered in step b, the first arc gate set in the vertical shaft gate chamber on the upstream side of the ecological diversion tunnel is used to control the discharge and water storage in the first phase. The rising speed of the water level in front of the dam in the first phase has little effect on the stability of the dam body. The rising speed of the water level in front of the dam is not controlled, and water should be stored as quickly as possible. The opening degree of the first arc gate for controlled discharge only needs to meet the requirements of ecological water supply. After reaching the controlled water level of the first phase of the first phase, the controlled discharge and water storage in the second phase of the first phase are carried out. The rising speed of the water level in front of the dam in this phase has a greater impact on the stability of the dam body, and the water level rising speed should be controlled. The first arc gate is used for controlled discharge and water storage under the condition that the requirements of the super-high rockfill dam for the rising speed of water storage in this phase are met. When the water level reaches the controlled water level of the second phase of the first stage, the first arc gate will be lowered to the bottom, and the first arc gate will block the water, creating dry land construction conditions for the second permanent plug on the downstream side of the ecological diversion tunnel, and the construction of the second permanent plug will be carried out; after the first arc gate is lowered to the bottom, the upstream water will be discharged through the later No. 1 diversion tunnel, so that the discharged water will flow continuously; the controlled water level in the first stage shall not be lower than the elevation of the later No. 1 diversion tunnel;

[0013] d. With the increase of the filling elevation of the dam body, after the flood season in the second year, in the process of discharging the upstream water from the later No. 1 diversion tunnel, the second stage of controlled discharge and water storage is carried out through the second arc gate in the second bank tower gate chamber of the later No. 1 diversion tunnel, and controlled discharge and water storage are carried out under the condition of meeting the requirements of the water storage rising speed of the ultra-high rockfill dam in this stage. When the water level reaches the second stage control water level, the second flat gate in the second bank tower gate chamber of the later No. 1 diversion tunnel is closed to block water, creating dry land construction conditions for the third permanent plug on the downstream side of the tunnel body of the later No. 1 diversion tunnel, and the construction of the third permanent plug in the later No. 1 diversion tunnel is carried out; after the second flat gate in the second bank tower gate chamber of the later No. 1 diversion tunnel is closed, the upstream water is discharged through the later No. 2 diversion tunnel, so that the discharged water flows continuously; the second stage control water level is not lower than the elevation of the later No. 2 diversion tunnel;

[0014] e. With the increase of the filling elevation of the dam body, after the flood season in the third year, in the process of discharging the upstream water from the later No. 2 diversion tunnel, the second arc gate in the second bank tower gate chamber in the later No. 2 diversion tunnel is used for the third stage of controlled discharge and water storage. The controlled discharge and water storage are carried out under the condition that the requirements of the water storage rising speed of the ultra-high rockfill dam in this stage are met. When the water level reaches the third stage control water level, the second flat gate in the second bank tower gate chamber in the later No. 2 diversion tunnel is closed to block water, creating dry land construction conditions for the third permanent plug on the downstream side of the tunnel body of the later No. 2 diversion tunnel, and the construction of the third permanent plug in the later No. 2 diversion tunnel is carried out; after the second flat gate in the second bank tower gate chamber in the later No. 2 diversion tunnel is closed, the upstream water is discharged through the venting hole and / or the deep hole flood discharge tunnel, so that the discharged water flow is continuous;

[0015] f. When the construction of all permanent plugs in the diversion tunnel group structure is completed and meets the water-retaining conditions, the entire gate lowering and plugging is completed.

[0016] Furthermore, in step a, after the first flat gate is lowered and before the temporary plug is completed and meets the water-blocking conditions, the ecological diversion tunnel discharges the upstream water at the maximum discharge opening.

[0017] The beneficial effects of the present invention are:

[0018] (1) The present invention ingeniously optimizes the sluice-closing procedure. Through tunnels at each level and corresponding arc gates, multi-stage controlled discharge and water storage are adopted to achieve the connection of the sluice-closing process of diversion tunnels at each level and ensure the continuous flow of water. At the same time, the controlled discharge and water storage are carried out in stages and step by step according to the plugging sequence of diversion tunnels at each level. On the one hand, it provides construction conditions for the plugging of diversion tunnels at each level. On the other hand, when the water storage reaches a certain height, the water storage rising speed can be effectively controlled to meet the requirements for the water storage rising speed during the water storage process of the ultra-high dam at each stage.

[0019] (2) In the process of closing the primary and secondary diversion tunnels, the present invention cleverly sets a temporary plug in the primary and secondary diversion tunnel to block water, thereby creating dry land construction conditions for the first permanent plug in the primary and secondary diversion tunnel, replacing the situation of water blocking by the first flat gate in traditional thinking, and the water blocking reliability is higher. In addition, after the first flat gate is closed, the first arc gate of the ecological diversion tunnel is fully opened, and the upstream water is discharged through the ecological diversion tunnel, which expands the function of the ecological diversion tunnel, minimizes the water blocking head of the first flat gate, and greatly reduces the water blocking head requirement of the first flat gate in the primary and secondary diversion tunnel. The design scale of the first flat gate and the hoist system is determined by this, which further brings the following benefits: ① The stress conditions of the inlet structure of the primary and secondary diversion tunnel are significantly improved, and the safety of the gate water blocking and structural pressure resistance is improved; ② The scale of the first flat gate and the hoist system is significantly reduced, saving engineering investment, and the first flat gate and equipment can be recycled.

[0020] (3) The present invention arranges the ecological diversion tunnel and the primary and secondary diversion tunnel at the same elevation, which can maximize the discharge capacity of the ecological water supply tunnel and minimize the water retaining head of the primary and secondary diversion tunnel blocking gate. At the same time, it can effectively meet the requirements of downstream ecological water supply through the ecological water supply tunnel after the primary and secondary diversion tunnel is closed, thereby achieving continuous flow of downstream ecological water supply.

[0021] (4) The present invention realizes the smooth closure of diversion tunnels at each level by setting up at least three levels of diversion tunnels consisting of an initial and intermediate diversion tunnel, a late No. 1 diversion tunnel, and a late No. 2 diversion tunnel, thereby ensuring the effective connection and uninterrupted flow of downstream ecological water supply, and realizing the synchronous matching of the closure of diversion tunnels at each level with the controlled discharge and water storage at each stage of the dam, effectively controlling the dam water storage process, and ensuring the effective connection of the dam water storage process and the safety requirements of the water storage process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a plan layout diagram of the diversion tunnel group structure of the ultra-high rockfill dam of the present invention.

[0023] Figure 2 This is the longitudinal section of the diversion tunnel in the early and middle stages.

[0024] Figure 3 This is the longitudinal section of the ecological diversion tunnel.

[0025] Figure 4 This is the longitudinal section corresponding to the later No. 1 diversion tunnel and the later No. 2 diversion tunnel.

[0026] Marked in the figure are: initial and intermediate diversion tunnel 1, first bank tower lock chamber 11, first flat gate 12, first permanent plug 13, temporary plug 14, ecological diversion tunnel 2, vertical shaft lock chamber 21, first arc gate 22, second permanent plug 23, later No. 1 diversion tunnel 3A, later No. 2 diversion tunnel 3B, second bank tower lock chamber 31, second flat gate 32, second arc gate 33, third permanent plug 34, drain hole 4, deep hole flood discharge tunnel 5, and dam body 6. DETAILED DESCRIPTION

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

[0028] like Figures 1 to 4As shown, the structure of the diversion tunnel group of the ultra-high rockfill dam of the present invention includes an initial and intermediate diversion tunnel 1, an ecological diversion tunnel 2, a later No. 1 diversion tunnel 3A, a later No. 2 diversion tunnel 3B, an emptying tunnel 4 and a deep hole flood spillway tunnel 5, and each of the above tunnels is connected to the upstream river channel and the downstream river channel of the dam body 6. The initial and intermediate diversion tunnel 1 is arranged at the lowest elevation, the ecological diversion tunnel 2 and the initial and intermediate diversion tunnel 1 are arranged at the same elevation, the later No. 1 diversion tunnel 3A is arranged at an elevation higher than the initial and intermediate diversion tunnel 1 and lower than the later No. 2 diversion tunnel 3B; the elevations of the air-raid shelter 4 and the deep hole flood spillway tunnel 5 are reasonably designed according to the actual situation of the dam, and are usually higher than the initial and intermediate diversion tunnel 1 and lower than the later No. 1 diversion tunnel 3A. The inlet section of the initial and intermediate diversion tunnel 1 is provided with a first bank tower lock chamber 11, and the first flat plate gate 12 is provided in the first bank tower lock chamber 11. The first permanent plug 13 is provided in the tunnel section of the initial and intermediate diversion tunnel 1, and a temporary plug 14 is provided immediately upstream of the first permanent plug 13. A shaft lock chamber 21 is provided upstream of the tunnel section of the ecological diversion tunnel 2, and a first arc gate 22 is provided in the shaft lock chamber 21. A second permanent plug 23 is provided downstream of the tunnel section of the ecological diversion tunnel 2. The inlet sections of the later No. 1 diversion tunnel 3A and the later No. 2 diversion tunnel 3B are respectively provided with a second shore tower lock chamber 31, and a second flat gate 32 and a second arc gate 33 are provided in the second shore tower lock chamber 31, and a third permanent plug 34 is provided downstream of the tunnel section of the later No. 1 diversion tunnel 3A and the later No. 2 diversion tunnel 3B.

[0029] The ultra-high rockfill dam in the present invention refers to a dam body 6 with a height of more than 200 meters. In this case, the overall construction and water storage period of the dam is relatively long. Compared with low dams, ultra-high rockfill dams have different characteristics and more engineering problems.

[0030] The present invention is aimed at the ultra-high rockfill dam, and the height of the dam body 6 is relatively high. Therefore, the initial and intermediate diversion tunnel 1, the later No. 1 diversion tunnel 3A and the later No. 2 diversion tunnel 3B are used for three-level layered diversion, which can better connect the sluice and plugging processes of the tunnels at each level.

[0031] The present invention also provides a method for closing a gate and plugging a diversion tunnel group of an ultra-high rockfill dam, wherein the method forms the above-mentioned diversion tunnel group structure of the ultra-high rockfill dam; the year when the diversion tunnel group is closed and plugged is taken as the first year, and the method comprises the following steps:

[0032] a. After the flood season of the first year, the first flat gate 12 in the first bank tower lock chamber 11 of the initial and intermediate diversion tunnel 1 is first closed, and water is blocked by the first flat gate 12 to create dry land construction conditions for the temporary plug 14 of the initial and intermediate diversion tunnel 1, and the temporary plug 14 is constructed; after the first flat gate 12 is closed, the upstream water is discharged through the ecological diversion tunnel 2 to ensure that the discharged water flows continuously;

[0033] b. After the temporary plug 14 in the primary and secondary diversion tunnel 1 is completed and meets the water-blocking condition, the first flat gate 12 is opened and recovered to allow water to flow into the primary and secondary diversion tunnel 1. At this time, the temporary plug 14 blocks the water, creating dry land construction conditions for the first permanent plug 13 in the body of the primary and secondary diversion tunnel 1, and the construction of the first permanent plug 13 is carried out;

[0034] c. After the first flat gate 12 is opened and recovered in step b, the first stage of controlled discharge and water storage is carried out through the first arc gate 22 set in the vertical shaft gate chamber 21 on the upstream side of the tunnel section of the ecological diversion tunnel 2, and controlled discharge and water storage are carried out while meeting the requirements of the water storage rising speed of the ultra-high rockfill dam at this stage. When the water level reaches the first stage control water level, the first arc gate 22 is lowered to the bottom, and the first arc gate 22 is used to block water, creating dry land construction conditions for the second permanent plug 23 on the downstream side of the tunnel section of the ecological diversion tunnel 2, and the construction of the second permanent plug 23 is carried out; after the first arc gate 22 is lowered to the bottom, the upstream water is discharged through the later No. 1 diversion tunnel 3A, so that the discharged water flows continuously; the first stage control water level is not lower than the elevation of the later No. 1 diversion tunnel 3A;

[0035] d. After the flood season of the second year, in the process of discharging upstream water from the later No. 1 diversion tunnel 3A, the second stage of controlled discharge and water storage is carried out through the second arc gate 33 in the second bank tower gate chamber 31 in the later No. 1 diversion tunnel 3A. Under the condition of meeting the requirements of the water storage rising speed of the ultra-high rockfill dam at this stage, controlled discharge and water storage are carried out. When the water level reaches the second stage control water level, the second flat gate 32 in the second bank tower gate chamber 31 in the later No. 1 diversion tunnel 3A is closed to block water, creating dry land construction conditions for the third permanent plug 34 on the downstream side of the tunnel body of the later No. 1 diversion tunnel 3A, and the construction of the third permanent plug 34 in the later No. 1 diversion tunnel 3A is carried out; after the second flat gate 32 in the second bank tower gate chamber 31 in the later No. 1 diversion tunnel 3A is closed, the upstream water is discharged through the later No. 2 diversion tunnel 3B, so that the discharged water flow is continuous; the second stage control water level is not lower than the elevation of the later No. 2 diversion tunnel 3B;

[0036] e. After the flood season of the third year, in the process of discharging upstream water from the later No. 2 diversion tunnel 3B, the second arc gate 33 in the second bank tower gate chamber 31 in the later No. 2 diversion tunnel 3B is used for the third stage of controlled discharge and water storage. The controlled discharge and water storage are carried out under the condition of meeting the requirements of the water storage rising speed of the ultra-high rockfill dam in this stage. When the water level reaches the third stage control water level, the second flat gate 32 in the second bank tower gate chamber 31 in the later No. 2 diversion tunnel 3B is closed to block water, creating dry land construction conditions for the third permanent plug 34 on the downstream side of the tunnel body of the later No. 2 diversion tunnel 3B, and the construction of the third permanent plug 34 in the later No. 2 diversion tunnel 3B is carried out; after the second flat gate 32 in the second bank tower gate chamber 31 in the later No. 2 diversion tunnel 3B is closed, the upstream water is discharged through the venting hole 4 and / or the deep hole flood discharge tunnel 5, so that the discharged water flow is continuous.

[0037] f. When the construction of all permanent plugs in the diversion tunnel group structure is completed and meets the water-retaining conditions, the entire gate lowering and plugging is completed.

[0038] In step a, the purpose of lowering the first flat gate 12 to block water is mainly to provide dry land construction conditions for the construction of the temporary plug 14, and preliminary water storage can also be started at the same time; when the temporary plug 14 is completed and meets the water-blocking conditions, the temporary plug 14 can be used to block water. In this way, the initial and middle period of the diversion tunnel 1 is divided into two stages according to the different blocking heads. The water head is blocked by the first flat gate 12 in the early stage, and the water head is blocked by the temporary plug 14 in the later stage. Therefore, the water head requirement for the first flat gate 12 can be reduced, thereby effectively reducing the scale of the first flat gate 12 and the supporting hoist system, and finally effectively reducing the project investment; after the temporary plug 14 is completed and meets the water-blocking conditions, the first flat gate 12 can be directly recovered to further save project investment.

[0039] In addition, during the construction of the temporary plug 14, the first flat gate 12 is mainly used to block water. In order to minimize the water head at this stage, the present invention further defines step a: after the first flat gate 12 is lowered and before the temporary plug 14 is completed and has the water blocking conditions, the ecological diversion tunnel 2 discharges the upstream water at the maximum discharge opening. In this way, during the construction of the entire temporary plug 14, the water storage level can be controlled to be at a lower state as much as possible, reducing the water head requirement for the first flat gate 12. After the temporary plug 14 is completed and has the water blocking conditions, the temporary plug 14 can be used to block water, so the first stage of the controlled discharge and water storage process can be carried out.

[0040] In addition, since the present invention arranges the ecological diversion tunnel 2 and the primary and secondary diversion tunnel 1 at the same elevation, after the primary and secondary diversion tunnel 1 is closed, the downstream ecological water supply can be directly connected through the ecological diversion tunnel 2 to ensure that the downstream ecological water supply is connected and flows continuously, thereby effectively protecting the ecological environment of the downstream river channel.

[0041] In addition, the present invention also utilizes arc gates to control the downstream water flow rate, and can control the upstream water storage speed when necessary. It can control the discharge and storage of water according to the requirements of the ultra-high rockfill dam on the water storage rising speed, thereby ensuring the safety of the dam's water storage process.

[0042] In addition, the present invention uses at least three levels of diversion tunnels consisting of an initial and intermediate diversion tunnel, a late No. 1 diversion tunnel, and a late No. 2 diversion tunnel, and the closure of the diversion tunnels at each level is carried out in stages, and is synchronously matched with the discharge control and water storage at each stage of the dam, effectively controlling the dam water storage process, ensuring the effective connection of the dam water storage process and the safety requirements of the water storage process. At the same time, the present invention also strictly controls the closure of the tunnels at each level to be carried out after the flood season of the river according to the flow conditions of the river, and the construction is convenient.

[0043] The tunnels at each level are blocked and connected in sequence. Under the condition of corresponding control of the water storage level, the downstream ecological water supply can be kept flowing, which effectively ensures the ecological diversion during the construction of the sluice and blocking of the diversion tunnels at each level and protects the ecological environment of the downstream river.

[0044] For the emptying hole 4 and the deep hole flood discharge tunnel 5, the present invention uses them to carry out corresponding ecological water supply during the process of closing the gates of the diversion tunnel group of the ultra-high rockfill dam. After the initial and intermediate diversion tunnel 1, the ecological diversion tunnel 2, the late No. 1 diversion tunnel 3A and the late No. 2 diversion tunnel 3B are all closed, the construction process of the closing gate and closing method of the diversion tunnel group of the ultra-high rockfill dam of the present invention is completed.

Claims

1. A method for closing the diversion tunnels of a super-high core rockfill dam, characterized by: The sluice-lowering and blocking method forms a diversion tunnel group structure of an ultra-high core wall rockfill dam, which includes an initial and intermediate diversion tunnel (1), an ecological diversion tunnel (2), a later No. 1 diversion tunnel (3A), a later No. 2 diversion tunnel (3B), a venting tunnel (4) and a deep hole flood spillway tunnel (5); the initial and intermediate diversion tunnel (1) is arranged at the lowest elevation, the ecological diversion tunnel (2) and the initial and intermediate diversion tunnel (1) are arranged at the same elevation, the later No. 1 diversion tunnel (3A) is arranged at an elevation higher than the initial and intermediate diversion tunnel (1) and lower than the later No. 2 diversion tunnel (3B), the venting tunnel (4) and the deep hole flood spillway tunnel (5) are arranged at elevations higher than the initial and intermediate diversion tunnel (1) and lower than the later No. 1 diversion tunnel (3A); the inlet section of the initial and intermediate diversion tunnel (1) is provided with a first bank tower lock chamber (11), the first A first flat gate (12) is provided in the bank tower lock chamber (11), a first permanent plug (13) is provided in the tunnel section of the initial and intermediate diversion tunnel (1), and a temporary plug (14) is provided immediately upstream of the first permanent plug (13); a vertical shaft lock chamber (21) is provided upstream of the tunnel section of the ecological diversion tunnel (2), a first arc gate (22) is provided in the vertical shaft lock chamber (21), and a second permanent plug (23) is provided downstream of the tunnel section of the ecological diversion tunnel (2); a second bank tower lock chamber (31) is provided at the inlet section of the later No. 1 diversion tunnel (3A) and the later No. 2 diversion tunnel (3B), a second flat gate (32) and a second arc gate (33) are provided in the second bank tower lock chamber (31), and a third permanent plug (34) is provided downstream of the tunnel section of the later No. 1 diversion tunnel (3A) and the later No. 2 diversion tunnel (3B); The year when the diversion tunnel group is sealed by the sluice gate is taken as the first year. The sluice gate sealing method includes the following steps: a. After the flood season of the first year, the first flat gate (12) in the first bank tower lock chamber (11) of the initial and intermediate diversion tunnel (1) is first closed, and water is blocked by the first flat gate (12) to create dry land construction conditions for the temporary plug (14) of the tunnel body of the initial and intermediate diversion tunnel (1), and the temporary plug (14) is constructed; after the first flat gate (12) is closed, the first arc gate (22) of the ecological diversion tunnel (2) is fully opened, and the upstream water is discharged through the ecological diversion tunnel (2), so that the discharged water flow is continuous; b. After the temporary plug (14) in the primary and secondary diversion tunnel (1) is completed and meets the water-blocking condition, the first flat gate (12) is opened and recovered to allow water to flow into the primary and secondary diversion tunnel (1). At this time, the temporary plug (14) blocks the water, creating dry land construction conditions for the first permanent plug (13) in the body of the primary and secondary diversion tunnel (1), and the construction of the first permanent plug (13) is carried out; c. After the first flat gate (12) is opened and recovered in step b, the controlled discharge and water storage of the first phase of the first stage is carried out through the first arc gate (22) arranged in the vertical shaft gate chamber (21) on the upstream side of the tunnel section of the ecological diversion tunnel (2). The rising speed of the water level in front of the dam is not controlled. The controlled discharge opening of the first arc gate (22) only needs to meet the requirements of ecological water supply. After reaching the controlled water level of the first phase of the first stage, the controlled discharge and water storage of the second phase of the first stage are carried out. When the requirements of the water storage rising speed of the ultra-high core wall rockfill dam in this stage are met, Control the discharge and store water; when the water level reaches the first stage control water level, the first arc gate (22) is lowered to the bottom, and the first arc gate (22) blocks water, creating dry land construction conditions for the second permanent plug (23) on the downstream side of the ecological diversion tunnel (2), and the construction of the second permanent plug (23) is carried out; after the first arc gate (22) is lowered to the bottom, the upstream water is discharged through the later No. 1 diversion tunnel (3A), so that the discharged water flow is continuous; the first stage control water level is not lower than the elevation of the later No. 1 diversion tunnel (3A); d. After the flood season in the second year, during the process of discharging the upstream water from the No. 1 diversion tunnel (3A) in the later stage, the second arc gate (33) in the second bank tower gate chamber (31) in the No. 1 diversion tunnel (3A) in the later stage is used for the second stage of controlled discharge and water storage. Under the condition that the water storage rising speed requirement of the ultra-high core wall rockfill dam in this stage is met, controlled discharge and water storage are carried out. When the water level reaches the second stage control water level, the second bank tower gate chamber (31) in the No. 1 diversion tunnel (3A) in the later stage is closed. 1) to block water, create dry land construction conditions for the third permanent plug (34) on the downstream side of the tunnel section of the later No. 1 diversion tunnel (3A), and carry out the construction of the third permanent plug (34) in the later No. 1 diversion tunnel (3A); after the second flat gate (32) in the second bank tower lock chamber (31) in the later No. 1 diversion tunnel (3A) is closed, the upstream water is discharged through the later No. 2 diversion tunnel (3B), so that the discharged water flow is continuous; The water level in the second stage is controlled to be no lower than the elevation of the later No. 2 diversion tunnel (3B); e. After the flood season of the third year, during the process of discharging the upstream water from the No. 2 diversion tunnel (3B) in the later stage, the second arc gate (33) in the second bank tower gate chamber (31) in the No. 2 diversion tunnel (3B) in the later stage is used for the third stage of controlled discharge and water storage. Under the condition that the water storage rising speed requirement of the ultra-high core wall rockfill dam in this stage is met, controlled discharge and water storage are carried out. When the water level reaches the third stage control water level, the gate is closed and the second bank tower gate chamber (31) in the No. 2 diversion tunnel (3B) in the later stage is closed. The second flat gate (32) is used to block water, creating dry land construction conditions for the third permanent plug (34) on the downstream side of the body section of the No. 2 diversion tunnel (3B) in the later stage, and the construction of the third permanent plug (34) in the No. 2 diversion tunnel (3B) in the later stage is carried out; after the second flat gate (32) in the second bank tower lock chamber (31) in the No. 2 diversion tunnel (3B) is closed, the upstream water is discharged through the venting hole (4) and / or the deep hole flood discharge tunnel (5), so that the downstream water flow is continuous; f. When the construction of all permanent plugs in the diversion tunnel group structure is completed and meets the water-retaining conditions, the entire gate lowering and plugging is completed.

2. The method for closing the diversion tunnels of the ultra-high core rockfill dam according to claim 1, characterized in that: In step a: after the first flat gate (12) is lowered and before the temporary plug (14) is completed and meets the water-blocking conditions, the ecological diversion tunnel (2) discharges the upstream water at the maximum discharge opening.

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