Staged water storage structure for dam water storage in advance

Abstract

The utility model relates to a staging water storage structure for dam water storage in advance. According to the technical scheme, the staging water storage structure used for dam water storage in advance is characterized in that a spillway is arranged on at least one side of a dam body of the dam, the upstream end of the spillway is located on the upstream of the dam body of the dam, a bottom plate of the upstream end is lower than the normal water storage level of a reservoir, and the downstream end of the spillway is located on the downstream of the dam body of the dam; an overflow weir is arranged at the upstream end of the spillway, the top of the overflow weir is as high as the normal storage level of the reservoir, and a notch section is reserved on the overflow weir. Thus, after dam body construction is completed, gate lowering and water storage can be conducted on the dam, when construction is conducted on the top of the dam, after the water storage amount of the upstream side of the dam is increased and the water level rises, redundant stored water on the upstream side of the dam can be discharged through the spillway under the action of the notch section of the overflow weir, and therefore the dam top is constructed. And the water level of the upstream side of the dam is prevented from rising to the dam crest position to affect dam crest construction of the dam.

Description

Technical Field

[0001] The utility model relates to a staged water storage structure for early water storage of a dam, which is applicable to the technical field of dam engineering. Background Technique

[0002] In the water conservancy and hydropower industries, it is necessary to build dams into reservoirs according to local conditions in combination with topographic and geological conditions, intercept natural runoff, and converge into reservoirs. To meet the flood control requirements during the operation period, reservoirs usually require spillways for flood discharge. A spillway is excavated in the geology beside the dam, and an overflow weir is arranged at the entrance position of the spillway, which is used to enable water flow to overflow into the spillway from the overflow weir and be discharged from the spillway when the water level in the reservoir on the upstream side of the dam is relatively high.

[0003] For a project with an earth-rock dam type of dam, during the construction period, it is required that the dam and the spillway be completely constructed according to the design requirements before closing the sluice for water storage. The dam crest is provided with a wave wall, a cable trench, and a road surface, with a complex structure and a tight construction period. Usually, at the established sluice closing time node, the dam crest structure has not been completed yet, which cannot meet the sluice closing requirements, affecting the sluice closing water storage and the overall construction period of the project, directly resulting in an increase in the project construction period and investment and damage to the power generation benefit. Content of the Utility Model

[0004] The technical problem to be solved by the utility model is: To solve the above technical problem, the utility model provides a staged water storage structure for early water storage of a dam.

[0005] The technical solution adopted by the utility model is: A staged water storage structure for early water storage of a dam, characterized in that: a spillway is arranged on at least one side of the dam body, the upstream end of the spillway is located upstream of the dam body and the bottom plate of the upstream end is lower than the normal water storage level of the reservoir, and the downstream end of the spillway is located downstream of the dam body;

[0006] An overflow weir is provided at the upstream end of the spillway, the crest of the overflow weir is at the same height as the normal water storage level of the reservoir, and a notch section is reserved on the overflow weir. In this way, after the construction of the dam body is completed, the dam can be closed for water storage, so that the sluice can be closed for water storage before the dam crest construction is completed, avoiding affecting the overall project. After the established sluice closing time node, the construction of the dam crest can still continue, and the construction of the dam crest will not affect the water storage of the dam. During the construction of the dam crest, when the water volume on the upstream side of the dam is large, the water storage on the upstream side of the dam will discharge the excess water on the upstream section of the dam to the downstream section of the dam under the action of the notch section of the overflow weir, avoiding the water level on the upstream side of the dam rising to the position of the dam crest and affecting the construction of the dam crest.

[0007] The elevation of the bottom of the notch in the notch section is the same as that of the bottom slab at the upstream end of the spillway. In this way, when the water level in the upstream section of the dam is higher than the spillway, the water can flow out from the notch of the spillway, so as to ensure that the reservoir water level is lower than the normal storage level during the construction period, thereby reducing the requirements for the construction appearance of the dam at the time point of closing the sluice for water storage.

[0008] The flow-through surface of the overflow weir is arranged in an arc. In this way, when the water flow approaches the overflow weir, under the action of the arc-shaped flow-through surface, the water flow is smoothed, and at the same time, the scouring of the overflow weir can be weakened.

[0009] According to the initially proposed top elevation to be completed in the dam construction, which is used as the upper limit elevation of the water level rise in the reservoir during the construction period, and according to the maximum discharge requirement during the construction period, the width of the notch section of the overflow weir is determined. In this way, the excess water stored on the upstream side of the dam during the maximum discharge in the construction period can be discharged through the overflow weir, avoiding the rise of the water level on the upstream side of the dam due to the inability of the excess water stored on the upstream side of the dam to be discharged from the overflow weir and affecting the construction of the dam crest.

[0010] A staged water storage method for early water storage of a dam, which is applied to the above-mentioned staged water storage structure for early water storage of a dam, is characterized in that:

[0011] Determine the flood control standard of the dam and the water storage capacity of the reservoir on the upstream side of the dam;

[0012] Initially propose the top elevation of the dam project, and determine the maximum discharge of the water flow to be discharged through the overflow weir beside the dam according to the top elevation, the flood control standard of the dam and the water storage capacity of the reservoir;

[0013] According to the top elevation and the maximum discharge at the overflow weir, calculate the width of the overflow weir beside the dam and the width of the overflow weir at the entrance of the spillway;

[0014] Determine the top elevation of the dam project and the width of the notch section on the overflow weir;

[0015] During the construction of the dam body, carry out the construction of the spillway on the geology beside the dam body, and carry out the construction of the overflow weir at the entrance of the spillway according to the determined width of the notch section;

[0016] After the construction of the dam body is completed, carry out the construction of the dam crest;

[0017] After the construction of the dam body, the spillway and the overflow weir are completed, carry out the sluice closure for water storage according to the set sluice time node, and at this time, the water storage elevation of the dam is the elevation of the bottom of the notch in the notch section on the overflow weir;

[0018] When the construction of the dam crest is completed and during the dry season, the overflow weir is completed to achieve water storage at the elevation of the dam crest. In this way, when the construction of the dam body is completed and there is a notch section on the overflow weir of the spillway, the dam can be impounded. At this time, the water storage elevation of the dam is the bottom elevation of the notch section on the overflow weir, and the water storage on the upstream side of the dam will not affect the construction project of the dam crest; when the construction of the dam crest is completed and during the dry season, the overflow weir is completed, and water storage at the elevation of the dam crest can be achieved, thus realizing staged water storage.

[0019] The method for determining the top elevation to be constructed for the dam project is as follows: initially estimate the top elevation to be constructed for the dam project. Based on the initially estimated top elevation to be constructed for the dam, use this as the upper limit elevation of the water level rise during the construction period. According to the maximum discharge requirement during the construction period, determine the width of the notch section of the overflow weir, calculate the water level rise during the construction period, and adjust the width of the notch section of the overflow weir until it is obtained that the reserved notch width of the overflow weir is less than the total width of the overflow weir and the upper limit elevation of the water level rise during the construction period is lower than the top elevation to be constructed for the dam. Then, the width of the reserved notch section of the overflow weir and the top elevation to be constructed for the dam can be finally determined.

[0020] The beneficial effects of the present utility model are as follows: by setting a spillway beside the dam body during the construction of the dam body of the present utility model, arranging an overflow weir at the upstream end of the spillway, and providing a notch on the overflow weir that meets the maximum discharge during the construction period, it is convenient to carry out the impounding operation of the dam after the construction of the dam body and the spillway is completed, avoiding the slow construction of the overall dam project due to the cumbersome construction of the dam crest, as well as the impounding and the overall construction period. During the process of impounding the dam and constructing the dam crest, when the water storage volume on the upstream side of the dam increases and the water level rises, under the action of the notch section of the overflow weir, the operating water level of the reservoir on the upstream side of the dam is lower than the permanent normal water storage level, and the excess water storage on the upstream side of the dam can be discharged through the spillway, avoiding the water level on the upstream side of the dam rising to the position of the dam crest and thus affecting the construction of the dam crest; after the construction of the dam crest is completed, the overflow weir is completed, enabling the operating water level of the reservoir on the upstream side of the dam to reach the normal water storage level and ensuring the operation of the dam. When the construction of the dam body is completed and there is a notch section on the overflow weir of the spillway, the dam can be impounded. At this time, the water storage elevation of the dam is the bottom elevation of the notch section on the overflow weir, and the water storage on the upstream side of the dam will not affect the construction project of the dam crest; when the construction of the dam crest is completed and during the dry season, the overflow weir is completed, and water storage at the elevation of the dam crest can be achieved, thus realizing staged water storage. Description of the Drawings

[0021] Figure 1 : Schematic diagram of the dam crest construction structure in the background technology of the present utility model.

[0022] Figure 2 : Schematic diagram of the structures of the dam body, spillway and overflow weir in the present utility model.

[0023] Figure 3 : Structural sectional view of the spillway and the overflow weir in the present utility model.

[0024] Figure 4 : Schematic diagram of the reserved notch during the construction of the overflow weir in the spillway of the present utility model.

[0025] In the figure: 1. Reservoir; 2. Dam body; 3. Spillway; 4. Overflow weir; 5. Notch section. Specific implementation mode

[0026] The present utility model will be further described in detail below in conjunction with the accompanying drawings and through embodiments. The following embodiments are explanations of the present utility model, and the present utility model is not limited to the following embodiments.

[0027] This embodiment is a staged water storage structure for the dam to store water in advance. The dam has a dam body 2 and a dam crest. The dam crest of the dam is provided with a wave wall, a cable trench, and a road surface.

[0028] In this embodiment, during the construction of the dam, a spillway 3 is provided on at least one side of the dam body 2 of the dam. The upstream end of the spillway 3 is located upstream of the dam body 2 of the dam and the bottom plate of the upstream end is lower than the normal storage water level of the reservoir 1. The downstream end of the spillway 3 is located downstream of the dam body 2 of the dam. The top of the overflow weir 4 of the spillway 3 is at the same height as the normal storage water level of the reservoir 1. When the reservoir water level is higher than the normal storage water level, it can flow through the spillway 3 for self-flow flood discharge without gate control. The upstream end of the spillway 3 is provided with an overflow weir 4, and the crest of the overflow weir 4 is at the same height as the normal storage water level of the reservoir 1. The width of the spillway 3 is determined according to the permanent flood control requirements during the operation period.

[0029] In this embodiment, a notch section 5 is provided on the overflow weir 4 of the spillway 3 according to the maximum discharge demand during the construction period. After the construction of the dam body 2 and the spillway 3 is completed, the notch section 5 is retained on the overflow weir 4 of the spillway 3. At this time, after the dam is closed for water storage, the water level on the upstream side of the dam begins to rise. When the water storage on the upstream side of the dam increases and causes the water level on the upstream side of the dam to rise, when the water level rises to the position of the notch section 5 on the spillway 3, the water storage on the upstream side of the dam will be discharged to the downstream section of the dam through the spillway 3, avoiding the continuous rise of the water level on the upstream section of the dam to the construction position of the dam crest and thus affecting the construction of the dam crest. Under the action of the notch section 5 on the overflow weir 4, the operating water level of the reservoir 1 during the construction period is lower than the permanent normal storage water level.

[0030] In this embodiment, the overflow surface of the overflow weir 4 is arranged in an arc shape. In this way, when the water flow flows towards the overflow weir 4, under the action of the arc-shaped overflow surface, the water flow is smoothed, and at the same time, the scouring of the overflow weir 4 can be weakened.

[0031] In this embodiment, according to the initially proposed top elevation to be completed for the dam construction, this is used as the upper limit elevation of the water level rise in the reservoir during the construction period. According to the maximum discharge requirement during the construction period, the width of the notch section 5 of the overflow weir 4 is determined such that the excess water storage on the upstream side of the dam can be discharged through the overflow weir 4 during the maximum discharge in the construction period, avoiding the water level on the upstream side of the dam rising due to the inability of the excess water storage on the upstream side of the dam to be discharged from the overflow weir 4 and affecting the dam top construction.

[0032] In this embodiment, the bottom elevation of the notch section 5 on the overflow weir 4 is the same as the bottom elevation of the upstream end floor of the spillway 3. Thus, during the dam top construction process, when the water level on the upstream side of the dam is higher than the bottom elevation of the notch section 5 on the overflow weir 4, the excess water storage on the upstream side of the dam can overflow over the notch section 5 on the overflow weir 4 and be discharged to the downstream side of the dam through the spillway 3.

[0033] In this embodiment, after the dam top construction is completed, the notch section 5 on the overflow weir 4 is completed according to the design requirements during the dry season when the overflow weir 4 does not discharge flood.

[0034] In this embodiment, the method of staged water storage for the dam to store water in advance is as follows:

[0035] 1. According to the project scale, determine the flood control standard of the dam, and calculate the water storage volume of the reservoir 1 on the upstream side of the dam at the planned water storage time point;

[0036] 2. Initially propose the top elevation that the dam project needs to be constructed to at the time point of closing the sluice for water storage. According to the top elevation, the flood control standard of the dam, and the water storage volume of the reservoir 1, determine the maximum discharge of the water flow that needs to be discharged through the overflow weir 4 beside the dam during the construction period;

[0037] 3. According to the maximum discharge at the overflow weir 4 during the construction period, determine the width of the notch section 5 on the overflow weir 4 beside the dam;

[0038] 4. Since the notch section 5 of the overflow weir and the completed section of the overflow weir 4 have different shapes and water heads, the calculation methods and unit discharge are also different. The flood discharge capacity needs to be calculated separately. The sum of the discharges of the two sections is the flood discharge capacity for the temporary flood control during the construction period of the spillway 3.

[0039] 5. If, after reserving the entire width of the overflow weir 4 as the notch section 5, the water level rise calculated by the flood routing still exceeds the initially proposed top elevation that the dam project needs to be constructed to at the time point of closing the sluice for water storage, it is necessary to strengthen the resource input and increase the top elevation that the dam needs to be constructed to, that is, re - propose the top elevation that the dam project needs to be constructed to at the time point of closing the sluice for water storage.

[0040] 6. Repeat the process of steps 2 - 5 above until the water level rise calculated by the flood routing is lower than the initially proposed top elevation that the dam project needs to be constructed to at the time point of closing the sluice for water storage. At this point, finally determine the top elevation that the dam 2 needs to be constructed to at the time of closing the sluice for water storage and the width of the reserved notch section 5 on the overflow weir 4.

[0041] 7. The overflow weir notch section 5 is reserved integrally at full height. The entire overflow weir 4 of the notch section is not constructed, and the other sections are constructed according to the design drawings.

[0042] 8. After the dam crest structure is constructed, the reserved notch section 5 of the overflow weir is constructed according to the design requirements during the dry season when the overflow weir 4 is not discharging flood. The notch section 5 is reserved integrally at full height, and the same formwork and construction technology can be adopted. During the construction of the reserved notch section 5 of the overflow weir 4, the reservoir water level needs to be controlled not to exceed the elevation of the notch bottom, and an appropriate margin should be left to ensure dry construction and construction safety.

[0043] 9. Due to the reserved notch section 5 and the notch can discharge flood by gravity flow, the reservoir operation water level during the construction period is about one overflow weir 4 height lower than the permanent normal storage level, usually about 6 - 8m. Therefore, usually when the upper 6 - 8m section of the dam 2 is not constructed, the sluice can be closed in advance to store water.

[0044] 10. Before the notch section 5 of the overflow weir 4 is constructed, the lower reservoir operation water level cannot reach the original designed normal storage level, and the water level is usually at or below the elevation of the notch section 5 bottom; after the notch section 5 is constructed, the reservoir operation water level can reach the original designed normal storage level, which is the so-called staged water storage. The staged water storage is the water storage process formed by the reserved notch section 5 of the overflow weir. Closing the sluice in advance and saving the construction period are the main purposes of the reserved notch section 5 of the overflow weir.

[0045] The above is only the preferred specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution of the present utility model and its inventive concept, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present utility model.

Claims

1. A staged water storage structure for early water storage in a dam, characterized by: A spillway (3) is arranged on at least one side of the dam body (2), the upstream end of the spillway (3) is located upstream of the dam body (2) and the bottom plate of the upstream end is lower than the normal water storage level of the reservoir (1), and the downstream end of the spillway (3) is located downstream of the dam body (2); An overflow weir (4) is provided at the upstream end of the spillway (3), the top of the overflow weir (4) is at the same height as the normal water level of the reservoir (1), and a notch section (5) is reserved on the overflow weir (4).

2. The staged water storage structure for dam water storage in advance according to claim 1 is characterized in that: The notch bottom elevation of the notch section (5) is the same as the bottom plate at the upstream end of the spillway (3).

3. The staged water storage structure for dam water storage in advance according to claim 1 is characterized in that: The flow surface of the overflow weir (4) is arranged in an arc shape.

4. The staged water storage structure for dam water storage in advance according to claim 1 is characterized in that: The top elevation of the dam to be constructed is initially planned to be the upper limit elevation of the reservoir water level during the construction period, and the width of the notch section (5) on the overflow weir (4) is determined according to the maximum discharge demand during the construction period.

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