A diversion wall construction method

Abstract

The present invention provides a diversion wall construction method, wherein the diversion wall is located downstream of a dam and includes a first diversion wall and a second diversion wall. A hydropower station is provided on the left side of the dam, and spillway gates are sequentially provided on the right side of the dam. The spillway gates include a left gate and a right gate. The first diversion wall is located between the hydropower station and the left gate, and the second diversion wall is located between the left gate and the right gate. The length of the second diversion wall is greater than that of the first diversion wall. By rationally designing a construction method, the construction of the diversion wall downstream of the dam is realized, and the smooth operation of the downstream water flow is ensured.

Description

Technical Field

[0001] The present invention relates to the field of engineering construction, and in particular to a diversion wall construction method. Background Art

[0002] Water conservancy projects are a common form of engineering structure. Common water conservancy projects include reservoirs, irrigation areas, water supply projects, etc. For reservoir structures, according to different regulation capabilities, they can be divided into non-regulated reservoirs, daily regulation reservoirs, seasonal regulation reservoirs, annual regulation reservoirs or multi-year regulation reservoirs, etc. For reservoir structures, river water is blocked by dams. In order to achieve the power generation benefits of water resources, hydropower stations are often set up downstream of the dam. In order to discharge excess water during the flood season, it is often necessary to build spillway gates. When the spillway gates are working, the water volume downstream of the dam will increase, raising the downstream water level. At the same time, the discharge flow is unstable, which will affect the power generation of the hydropower station.

[0003] In order to avoid the impact of reservoir discharge on hydropower generation, a diversion wall is generally set up. The diversion wall is located between the gate and the hydropower station, so that the discharge flow from the discharge gate will affect the hydropower station as little as possible. However, even with only a diversion wall, the discharge from the gate will still cause the tailwater level of the hydropower station to increase, thereby affecting the operation of the hydropower station. Especially in the case of large discharge flow, this unstable operating condition will be more obvious. Summary of the Invention

[0004] In view of the problems of the prior art, the present invention provides a diversion wall construction method, which realizes the stable and safe operation of the reservoir dam by rationally setting the diversion wall and providing a scientific construction method.

[0005] The present invention provides a method for constructing a diversion wall, wherein the diversion wall is located downstream of a dam, the dam intercepts a river and forms a reservoir, the dam is a concrete gravity dam, a hydropower station is provided on the left side of the dam, and a spillway is provided on the right side of the dam, characterized in that the spillway includes a left-side gate and a right-side gate, and both the left-side gate and the right-side gate include a plurality of spillway gates, wherein the left-side gate is close to the hydropower station, the right-side gate is close to the right bank of the dam, and the right-side gate satisfies the requirement that the maximum flow of the right-side gate is 100% under the set water level of the reservoir. The maximum discharge capacity is not less than the full discharge of the hydropower station. The guide wall includes a first guide wall and a second guide wall. The first guide wall and the second guide wall are both reinforced concrete structures and are fixedly connected to the dam body. The first guide wall is located between the hydropower station and the left gate, and the second guide wall is located between the left gate and the right gate. The length of the second guide wall is greater than that of the first guide wall. The end of the first guide wall away from the dam is located downstream of the hydropower station powerhouse. The construction method includes the following construction steps:

[0006] S1: Construct a temporary diversion channel on the left bank of the dam. The temporary diversion channel is provided with a water diversion gate. The water diversion gate draws water from the reservoir. The water diversion gate is provided with an automatic control device to control the water intake of the water diversion gate to be greater than or equal to the ecological flow of the river. The end of the temporary diversion channel is connected to the river channel downstream of the dam. The distance between the end of the temporary diversion channel and the dam is greater than the length of the second diversion wall.

[0007] S2: Setting up a temporary fence upstream of the end of the temporary diversion channel, wherein the width of the temporary fence is the same as the width of the riverbed where the temporary fence is set up, and the distance between the temporary fence and the dam is greater than the length of the second diversion wall; by setting up the temporary fence, a dry construction environment is formed between the temporary fence and the dam;

[0008] S3: Build a first diversion wall between the left gate and the hydropower station, install a plurality of first embedded steel bars at the connection position between the dam and the first diversion wall, the first embedded steel bars extending out of the dam body, and install a plurality of first anchor rods downward at the riverbed where the first diversion wall is located, the first anchor rods penetrating into the foundation of the riverbed, which is a rock foundation. Tie the first anchor rods and the first embedded steel bars to form a first diversion wall reinforcement cage.

[0009] S4: construct a second diversion wall between the left gate and the right gate, install a plurality of second embedded steel bars at the connection position between the dam and the second diversion wall, the second embedded steel bars extending out of the dam body, install a plurality of second anchor rods downward at the riverbed where the second diversion wall is located, the second anchor rods penetrate into the foundation of the riverbed, the foundation of the riverbed being a rock foundation, and tie the second anchor rods and the second embedded steel bars to form a second diversion wall reinforcement cage;

[0010] S5: erect formwork, pour concrete for the first diversion wall and the second diversion wall respectively, and cure them to the designed strength, remove the formwork, and remove the temporary enclosure to complete the construction of the first diversion wall and the second diversion wall.

[0011] Preferably, the sizes of the discharge gates are all consistent, the discharge gates are flat steel gates, and each of the discharge gates is provided with a hoist.

[0012] Preferably, the first embedded steel bars and the second embedded steel bars are both inserted into the dam body, and the length of the first embedded steel bars and the second embedded steel bars extending out of the dam body is not less than 50 cm.

[0013] Preferably, the length of the second guide wall is greater than 1.5 times the length of the first guide wall.

[0014] The end of the temporary diversion channel is located farther from the dam than the length of the second diversion wall, and the temporary enclosure is located farther from the dam than the length of the second diversion wall. This means that both the end of the temporary diversion channel and the temporary enclosure are located downstream of the end of the second diversion wall away from the dam. The width of the temporary enclosure is the same as the width of the riverbed where the enclosure is installed. This means that the temporary enclosure completely blocks the river flow to prevent backflow.

[0015] The working principle of the present invention is as follows:

[0016] For dam-type reservoir hydropower stations, due to the limitation of water flow used for power generation in hydropower stations, in order to meet the requirements of flood control, multiple spillway gates are generally built next to the hydropower station to realize the discharge of water flow. Especially for reservoirs with smaller storage capacity, due to their effective regulation ability, their spillway gates need to be opened frequently. Once the spillway gates are opened, the water level downstream of the dam will rise, and then the tailwater level of the hydropower station will be raised, affecting the power generation head of the hydropower station. The discharge flow will also cause turbulence in the water flow downstream of the dam, affecting the power generation stability of the hydropower station. In order to reduce the impact between the spillway gate and the hydropower station and ensure the normal and efficient operation of the hydropower station, a diversion wall is generally built between the spillway gate and the hydropower station. However, if only one diversion wall is set up, the discharge flow from the spillway gate will still bypass the diversion wall, and then affect the hydropower station, especially the discharge of the spillway gate close to the hydropower station, which will have a greater impact on the operation of the hydropower station.

[0017] With respect to the setting mode of a single diversion wall, the present invention provides a diversion wall setting and construction method, wherein the discharge gate is divided into a left gate and a right gate, wherein the left gate is close to the hydropower station, a first diversion wall is constructed between the left gate and the hydropower station, and a second diversion wall is constructed between the left gate and the right gate, wherein at the set water level of the reservoir, such as the benefit water level or the normal water storage level, it should be ensured that the maximum discharge capacity of the right gate is not less than the full discharge of the hydropower station at the set water level. This setting mode can ensure that when it is necessary to discharge a flow below the full discharge of the hydropower station, the flow can be discharged through the right gate, and the right gate is far away from the hydropower station, and the right gate is far away from the hydropower station. The first guide wall and the second guide wall are separated, and the length of the second guide wall is greater than that of the first guide wall, so that when the flow is discharged through the right gate, its impact on the power generation of the hydropower station is greatly reduced. According to the flood control and power generation operation design of the reservoir, in order to avoid the waste of flood control flow, the flow discharged from the reservoir dam through the discharge gate is generally less than the full flow of the hydropower station in most periods. Therefore, the right gate division method provided by the present invention can ensure that the right gate of the reservoir is opened most of the time during the flood discharge period, ensuring that the impact on the power station is greatly reduced when discharging, which not only improves the power generation stability of the hydropower station, but also can increase the power generation head and ensure the power generation efficiency of the hydropower station.

[0018] A first distance is set between the left gate and the right gate, the distance between the discharge gates of the left gate is a second distance, the distance between the discharge gates of the right gate is equal to the second distance, the first distance is greater than the second distance, for example, it is selected to be twice the second distance. This setting method can make the left gate and the right gate form a relatively independent working flow channel to reduce the impact on each other's work.

[0019] The length of the second diversion wall is greater than that of the first diversion wall, so that the discharge of the left gate and the right gate is in different flow channels, reducing the impact of the discharge of the right gate on the hydropower station. During construction, in order to achieve dry construction, the reservoir water level can be lowered to a low water level first, and the ecological flow can be discharged through a temporary diversion channel. The distance between the end of the temporary diversion channel and the dam is greater than the length of the second diversion wall. In order to prevent the backflow of the discharged ecological flow, a temporary fence is set up to achieve dry environment construction of the first diversion wall and the second diversion wall, thereby improving construction efficiency.

[0020] During the construction of the dam body, pre-buried steel bars are set. For the construction of the diversion wall of the modified dam, holes are drilled on the completed dam body and steel bars are implanted to achieve pre-buried settings. This setting form can ensure the fixed connection between the diversion wall and the dam. Since the first diversion wall and the second diversion wall are impacted by the water flow, they are subjected to a large force. Through the setting of anchor rods, they are fixedly connected to the riverbed. Through the anchor rods, pre-buried steel bars and diversion wall steel bars, a fixed integral connection between the riverbed, dam and diversion wall structure is achieved, thereby improving the overall strength.

[0021] The advantages of the present invention are:

[0022] The present invention provides a diversion wall construction method, wherein the diversion wall is located downstream of a dam and includes a first diversion wall and a second diversion wall. A hydropower station is provided on the left side of the dam, and spillway gates are sequentially provided on the right side of the dam. The spillway gates include a left gate and a right gate. The first diversion wall is located between the hydropower station and the left gate, and the second diversion wall is located between the left gate and the right gate. The length of the second diversion wall is greater than that of the first diversion wall. By rationally designing a construction method, the construction of the diversion wall downstream of the dam is realized, and the smooth operation of the downstream water flow is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 Schematic diagram of the dam and diversion wall. DETAILED DESCRIPTION

[0025] The following is a detailed explanation of the contents defined in the present invention with reference to the drawings in the specification.

[0026] The present invention provides a method for constructing a diversion wall, wherein the diversion wall is located downstream of a dam 1, the dam 1 intercepts a river and forms a reservoir, the dam 1 is a concrete gravity dam, a hydropower station 2 is provided on the left side of the dam 1, and a spillway gate is provided on the right side of the dam 1, characterized in that: the spillway gate includes a left gate 3 and a right gate 4, the left gate 3 and the right gate 4 both include a plurality of spillway gates, wherein the left gate 3 is close to the hydropower station 2, the right gate 4 is close to the right bank of the dam 1, and the right gate 4 satisfies the set water level of the reservoir, the maximum flow of the right gate 4 The maximum discharge capacity is not less than the full discharge of the hydropower station 2. The guide wall includes a first guide wall 5 and a second guide wall 6. The first guide wall 5 and the second guide wall 6 are both reinforced concrete structures and are fixedly connected to the dam body of the dam 1. The first guide wall 5 is located between the hydropower station 2 and the left gate 3, and the second guide wall 6 is located between the left gate 3 and the right gate 4. The length of the second guide wall 6 is greater than that of the first guide wall 5. The end of the first guide wall 5 away from the dam 1 is located downstream of the powerhouse of the hydropower station 2. The construction method includes the following construction steps:

[0027] S1: A temporary diversion channel 7 is constructed on the left bank of the dam 1. The temporary diversion channel 7 is provided with a water diversion gate. The water diversion gate draws water from the reservoir. The water diversion gate is provided with an automatic control device to control the water intake of the water diversion gate to be greater than or equal to the ecological flow of the river. The end of the temporary diversion channel 7 is connected to the river channel downstream of the dam 1. The distance between the end of the temporary diversion channel 7 and the dam 1 is greater than the length of the second diversion wall 6.

[0028] S2: A temporary fence 8 is installed upstream of the end of the temporary diversion channel 7. The width of the temporary fence 8 is the same as the width of the riverbed where the temporary fence 8 is installed. The distance between the temporary fence 8 and the dam 1 is greater than the length of the second diversion wall 6. By installing the temporary fence 8, a dry construction environment is formed between the temporary fence 8 and the dam 1.

[0029] S3: Build a first diversion wall 5 between the left gate 3 and the hydropower station 2, set a plurality of first embedded steel bars at the connection position between the dam 1 and the first diversion wall 5, the first embedded steel bars extending out of the dam body 1, and set a plurality of first anchor rods downward at the riverbed where the first diversion wall 5 is located. The first anchor rods penetrate into the foundation of the riverbed, which is a rock foundation. Tie the first anchor rods and the first embedded steel bars to form a steel cage for the first diversion wall 5;

[0030] S4: Build a second diversion wall 6 between the left gate 3 and the right gate 4, set a plurality of second embedded steel bars at the connection position between the dam 1 and the second diversion wall 6, the second embedded steel bars extending out of the dam body of the dam 1, set a plurality of second anchor rods downward at the riverbed where the second diversion wall 6 is located, the second anchor rods penetrate into the foundation of the riverbed, the foundation of the riverbed being a rock foundation, and tie the second anchor rods and the second embedded steel bars to form a steel cage for the second diversion wall 6;

[0031] S5: erect formwork, pour concrete for the first guide wall 5 and the second guide wall 6 respectively, and cure them to the designed strength, remove the formwork, and remove the temporary enclosure 8, completing the construction of the first guide wall 5 and the second guide wall 6.

[0032] The set water level can be selected as the normal water level or the beneficial water level of the reservoir. Under the set water level, the maximum discharge capacity of the right gate 4 should not be less than the full discharge of the hydropower station 2 under the set water level. Since the second guide wall 6 is set between the right gate 4 and the left gate 3, when the right gate 4 is used to discharge the flow, it has less impact on the tail water of the hydropower station 2. Compared with the setting of a single guide wall, the power generation efficiency can be significantly improved and the rise of the tail water level can be avoided.

[0033] Preferably, the discharge gates are all of uniform size, are flat steel gates, and are each equipped with a hoist. The discharge gates may also be arc-shaped gates, etc., which meet the discharge capacity design and the flood control design of the reservoir.

[0034] Preferably, the first embedded steel bars and the second embedded steel bars are both embedded deep into the dam body of dam 1, and the length of the first embedded steel bars and the second embedded steel bars extending out of the dam body of dam 1 is not less than 50 cm. The first embedded steel bars and the second embedded steel bars can be pre-embedded during the construction of the dam body, or can be drilled after the construction of the dam body of dam 1 is completed.

[0035] Preferably, the length of the second guide wall 6 is greater than 1.5 times the length of the first guide wall 5. The specific setting lengths of the first guide wall 5 and the second guide wall 6 can be determined based on hydraulic simulation calculations or hydraulic tests.

[0036] In order to adapt to the water flow form, the first guide wall 5 and the second guide wall 6 can be set to an arc shape at the end away from the dam body of the dam 1 to adapt to the water flow form. When set to a straight segment, the steel bars of the first guide wall 5 and the second guide wall 6 at the end away from the dam body of the dam 1 should be denser to improve their overall strength.

[0037] The above embodiments are only preferred embodiments of the present invention. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the concept of the present invention.

Claims

1. A method for constructing a diversion wall, wherein the diversion wall is located downstream of a dam, the dam intercepting a river and forming a reservoir, the dam being a concrete gravity dam, a hydropower station being provided on the left side of the dam, and a spillway gate being provided on the right side of the dam, characterized in that: The discharge gate includes a left gate and a right gate, and the left gate and the right gate each include several discharge gates, wherein the left gate is close to the hydropower station, and the right gate is close to the right bank of the dam. The right gate satisfies that under the set water level of the reservoir, the maximum discharge capacity of the right gate is not less than the full discharge of the hydropower station. The guide wall includes a first guide wall and a second guide wall, and the first guide wall and the second guide wall are both reinforced concrete structures and are fixedly connected to the dam body. The first guide wall is located between the hydropower station and the left gate, and the second guide wall is located between the left gate and the right gate. The length of the second guide wall is greater than the length of the first guide wall. The end of the first guide wall away from the dam is located downstream of the hydropower station powerhouse. The construction method includes the following construction steps: S1: Construct a temporary diversion channel on the left bank of the dam. The temporary diversion channel is provided with a water diversion gate. The water diversion gate draws water from the reservoir. The water diversion gate is provided with an automatic control device to control the water intake of the water diversion gate to be greater than or equal to the ecological flow of the river. The end of the temporary diversion channel is connected to the river channel downstream of the dam. The distance between the end of the temporary diversion channel and the dam is greater than the length of the second diversion wall. S2: Setting up a temporary fence upstream of the end of the temporary diversion channel, wherein the width of the temporary fence is the same as the width of the riverbed where the temporary fence is set up, and the distance between the temporary fence and the dam is greater than the length of the second diversion wall; by setting up the temporary fence, a dry construction environment is formed between the temporary fence and the dam; S3: Build a first diversion wall between the left gate and the hydropower station, install a plurality of first embedded steel bars at the connection position between the dam and the first diversion wall, the first embedded steel bars extending out of the dam body, and install a plurality of first anchor rods downward at the riverbed where the first diversion wall is located, the first anchor rods penetrating into the foundation of the riverbed, which is a rock foundation. Tie the first anchor rods and the first embedded steel bars to form a first diversion wall reinforcement cage. S4: construct a second diversion wall between the left gate and the right gate, install a plurality of second embedded steel bars at the connection position between the dam and the second diversion wall, the second embedded steel bars extending out of the dam body, install a plurality of second anchor rods downward at the riverbed where the second diversion wall is located, the second anchor rods penetrate into the foundation of the riverbed, the foundation of the riverbed being a rock foundation, and tie the second anchor rods and the second embedded steel bars to form a second diversion wall reinforcement cage; S5: erect formwork, pour concrete for the first diversion wall and the second diversion wall respectively, and cure them to the designed strength, remove the formwork, and remove the temporary enclosure to complete the construction of the first diversion wall and the second diversion wall.

2. The guide wall construction method according to claim 1, wherein: The sizes of the discharge gates are all consistent, and the discharge gates are flat steel gates. Each of the discharge gates is provided with a hoist.

3. The guide wall construction method according to claim 1, wherein: The first pre-embedded steel bars and the second pre-embedded steel bars are both inserted deep into the dam body, and the length of the first pre-embedded steel bars and the second pre-embedded steel bars extending out of the dam body is not less than 50 cm.

4. The guide wall construction method according to claim 1, wherein: The length of the second guide wall is greater than 1.5 times the length of the first guide wall.

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