Sand retaining dam for hydraulic works and method for building same

Abstract

A water conservancy project sand retaining dam, comprising sand retaining dams respectively arranged at multiple water inlets of a reservoir, a water retaining dam arranged on the reservoir, and a sand collecting well arranged on a downstream side of the water retaining dam; the multiple sand retaining dams on the same side of the reservoir are connected in series through sand discharge channels or sand discharge holes, and the terminal sand retaining dam is connected to the sand collecting well through a sand discharge channel or a sand discharge hole; the water conservancy project sand retaining dam further comprises a diversion tunnel, which connects the reservoir and a river channel on the downstream side of the water retaining dam. A construction method of the water conservancy project sand retaining dam comprises the following steps: step S1, selecting an import and export position of the diversion tunnel and constructing the diversion tunnel; step S2, constructing the water retaining dam when the diversion tunnel is in flow; step S3, constructing the sand retaining dams at the multiple water inlets of the reservoir in dry season by using the flow of the diversion tunnel; step S4, constructing the sand discharge channels or sand discharge holes between the adjacent sand retaining dams and the sand discharge channels or sand discharge holes between the terminal sand retaining dam and the sand collecting well; and step S5, constructing the sand collecting well.

Description

Technical Field

[0001] This invention relates to the field of layout and construction of sediment-trapping dams in water conservancy projects, and particularly to a sediment-trapping dam for water conservancy projects and its construction method. Background Technology

[0002] In water conservancy construction, many water conservancy projects built on unfavorable terrain often have a high sediment content in reservoirs due to sand flushing during the rainy season, which cannot guarantee the normal water storage of the dam. Therefore, it is necessary to take measures to intercept and discharge sand to reduce excessive sediment accumulation and improve the water storage capacity of the reservoir.

[0003] In existing technologies, patent application CN115162280A discloses a superimposed water storage and sediment-trapping dam, which is built on the basis of an existing sediment-trapping dam to intercept sediment and retain sediment and floodwater within a miniature reservoir, replenishing the surface water. Another example is patent application CN115404821A, which discloses a buttress-type pre-sedimentation basin sediment-trapping dam structure. This structure includes a sedimentation basin and a sediment-trapping dam, with the dam located downstream of the sedimentation basin. The dam includes a dam body and a front heel plate, with the front heel plate located on the water-facing side of the dam body. This design fully utilizes the weight of the sediment deposited on the front heel plate and the weight of the water directly above it, reducing the dam's cross-section while ensuring dam stability. Simultaneously, the pre-sedimentation basin reduces the water flow velocity, allowing sediment to settle in the basin and improving sedimentation efficiency.

[0004] However, many current silt-trapping dam structures are designed as standalone structures, solely for silt trapping, rarely in conjunction with silt discharge channels or tunnels for silt removal. Over many years, this approach may lead to dam failure due to excessive siltation, resulting in increased sediment load in the reservoir, reduced water storage capacity, and inability to withstand flash floods, thus increasing the risk of flooding. Furthermore, due to topographical constraints, reservoirs often cannot meet the requirements of both water storage and silt removal using a single silt-trapping dam structure. Summary of the Invention

[0005] The main objective of this invention is to propose a sediment-trapping dam for water conservancy projects and its construction method, which solves the complex geological problems of situations where terrain conditions are limited and multiple sediment-trapping dams need to be set up, thereby reducing excessive sediment accumulation.

[0006] To achieve the above objectives, on the one hand, the present invention proposes a sediment-trapping dam for water conservancy projects, comprising sediment-trapping dams respectively set at multiple inlets of a reservoir, a water-retaining dam set on the reservoir, and a sediment collection well set on the downstream side of the water-retaining dam; multiple sediment-trapping dams located on the same side of the reservoir are connected in series by sediment discharge channels or sediment discharge tunnels, and the sediment-trapping dam at the end is connected to the sediment collection well by sediment discharge channels or sediment discharge tunnels; it also includes a diversion tunnel, which connects the reservoir to the river channel downstream of the water-retaining dam.

[0007] Preferably, if the geological conditions between two adjacent sand-retaining dams are Class IV or Class V, and the elevation difference between the two adjacent sand-retaining dams is less than 3 times the width of the sand-drainage tunnel, then the two sand-retaining dams are connected by a sand-drainage channel; if the geological conditions between two adjacent sand-retaining dams are Class I, Class II, or Class III, and the elevation difference between the two adjacent sand-retaining dams is greater than or equal to 3 times the width of the sand-drainage tunnel, then the two sand-retaining dams are connected by a sand-drainage tunnel.

[0008] Preferably, if the geological conditions between the end sand-blocking dam and the sand-collecting well are Class IV or Class V, and the height difference between the end sand-blocking dam and the sand-collecting well is less than 3 times the width of the sand-discharge tunnel, then the end sand-blocking dam and the sand-collecting well are connected by a sand-discharge channel; if the geological conditions between the end sand-blocking dam and the sand-collecting well are Class I, Class II, or Class III, and the height difference between two adjacent sand-blocking dams is greater than or equal to 3 times the width of the sand-discharge tunnel, then the end sand-blocking dam and the sand-collecting well are connected by a sand-discharge tunnel.

[0009] Preferably, the sand collection well is located on the left or right side downstream of the dam.

[0010] Preferably, the cross-section of the sand drainage channel is trapezoidal, with the following dimensions: upper base 3m~3.5m, lower base 1.8m~2.0m, and height 1.5m~2.0m.

[0011] Preferably, the sand discharge tunnel has a circular cross-section with a diameter of 1.5m to 2.5m.

[0012] Preferably, the sand collection well is a hollow cylindrical shape, with a sand retaining wall inside the sand collection well, which divides the sand collection well into a water pool and a sand-water mixing pool; the sand discharge channel or sand discharge hole between the sand retaining dam at the end and the sand collection well is connected to the sand-water mixing pool; the sand retaining wall is provided with water filter holes, and the bottom of the water pool is provided with a drain outlet; a dredging ladder is provided inside the sand collection well, with a slope of 1:0.8 to 1:1.

[0013] On the other hand, the present invention also proposes a method for constructing a silt-trapping dam for the above-mentioned water conservancy project, comprising the following steps:

[0014] Step S1: Select the inlet and outlet locations of the diversion tunnel and construct the diversion tunnel;

[0015] Step S2: When the diversion tunnel is overflowing, construct a dam to block the water.

[0016] Step S3: Utilize the diversion tunnel for flow, and construct sand-blocking dams at each inlet of the reservoir during the dry season;

[0017] Step S4: Construct a drainage channel or tunnel between adjacent sand-retaining dams, and construct a drainage channel or tunnel between the end sand-retaining dam and the sand collection well;

[0018] Step S5: Construct a sand collection well, and at the same time construct a dredging ladder inside the sand collection well, with the dredging ladder located on one side of the dam.

[0019] Preferably, step S3 includes the following steps when constructing the silt-trapping dam:

[0020] Step S301: Based on the geological survey results, draw detailed geological profiles of the area surrounding each water inlet of the reservoir;

[0021] Step S302: Calculate the maximum sediment discharge and sediment accumulation at each inlet of the reservoir during the flood season, determine the inlet where a sediment-blocking dam needs to be built, and construct the sediment-blocking dam at that inlet.

[0022] Preferably, in step S4, when constructing a sand drainage channel or sand drainage tunnel, the geological conditions between two adjacent sand-blocking dams and between the end sand-blocking dam and the sand collection well are first determined. At the same time, the elevation difference between two adjacent sand-blocking dams and between the end sand-blocking dam and the sand collection well are determined. Based on the geological conditions and elevation differences, a sand drainage channel or a sand drainage tunnel is selected for connection.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0024] (1) The water conservancy engineering sand-blocking dam structure provided by the present invention includes multiple sand-blocking dams, a sand collection well is set on one side near the water-blocking dam, multiple sand-blocking dams are connected in series through sand discharge channels or sand discharge tunnels, and the sand-blocking dam at the end is connected to the sand collection well through sand discharge channels or sand discharge tunnels. The sand discharge channels or sand discharge tunnels are used for sand discharge or flood control, and the sand collection wells utilize sand collection to reduce siltation downstream.

[0025] (2) In this invention, the sand-blocking dam is set up in series on the same side, which is suitable for unfavorable terrain with large sand content or large sand discharge. The sand-blocking dam can effectively intercept sediment, and the sand discharge channel or sand discharge tunnel can discharge sediment to the sand collection well, ensuring the safety of the dam during the flood season, reducing the excessive sediment accumulation of the dam, and improving the dam's water storage capacity.

[0026] (3) The water conservancy engineering sand-blocking dam provided by the present invention has a relatively simple structure and a relatively flexible layout. The sand-drainage channel or sand-drainage tunnel has significant effects on sand discharge, drainage, and flood control, effectively reducing the later dredging work of the dam, saving costs, and ensuring the water storage capacity of the dam.

[0027] (4) The water conservancy engineering sand-blocking dam structure provided by the present invention is applicable to the arrangement of 1, 2, 3...n sand-blocking dams. It adopts sand-drainage tunnels and sand-drainage channels as sand-drainage structures, which can solve the problems of complex terrain, excessive sediment accumulation, large amount of sand flushing during the flood season, etc., and ensure the normal reservoir capacity and service life of the dam. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall layout of the first scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0030] Figure 2 This is a schematic diagram of the overall layout of the second scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0031] Figure 3 This is a schematic diagram of the overall layout of the third scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0032] Figure 4 This is a schematic diagram of the overall layout of the fourth scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0033] Figure 5 This is a schematic diagram of the overall layout of the fifth scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0034] Figure 6 This is a schematic diagram of the overall layout of the sixth scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0035] Figure 7 This is a schematic diagram of the overall layout of the seventh scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0036] Figure 8 This is a schematic diagram of the overall layout of the eighth scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0037] Figure 9 This is a schematic diagram of the overall layout of the ninth scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0038] Figure 10 This is a schematic diagram of the overall layout of the 10th scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0039] Figure 11 This is a schematic diagram of the overall layout of the 11th scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0040] Figure 12 This is a schematic diagram of the overall layout of the 12th scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0041] Figure 13This is a schematic diagram of the overall layout of the 13th scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0042] Figure 14 This is a schematic diagram of the overall layout of the 14th scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0043] Figure 15 This is a schematic diagram of the overall layout of the 15th scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0044] Figure 16 This is a schematic diagram of the overall layout of the 16th scheme of a water conservancy engineering silt-trapping dam provided by the present invention;

[0045] Figure 17 This is a schematic diagram of the first scheme for connecting the sand-trapping dam and the sand-collecting well in this invention;

[0046] Figure 18 This is a schematic diagram of the second scheme for connecting the sand-trapping dam and the sand-collecting well in this invention;

[0047] Figure 19 This is a schematic diagram of the sand-collecting internal retaining wall in this invention;

[0048] Figure 20 This is a flowchart of a method for constructing a silt-trapping dam in a water conservancy project.

[0049] The following are the diagram labels: 1. Reservoir; 2. First sand-trapping dam; 3. Second sand-trapping dam; 4. Third sand-trapping dam; 5. Fourth sand-trapping dam; 6. Water-retaining dam; 7. Sand collection well; 8. First sand-drainage channel; 9. Second sand-drainage channel; 10. Third sand-drainage channel; 11. Fourth sand-drainage channel; 12. First sand-drainage tunnel; 13. Second sand-drainage tunnel; 14. Third sand-drainage tunnel; 15. Fourth sand-drainage tunnel; 16. Diversion tunnel; 17. Water pool; 18. Sand-water mixing pool; 19. Sand-retaining wall; 20. Filter hole; 21. Drainage outlet; 22. Dredging ladder. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0052] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0053] As shown in the attached drawings, a water conservancy project silt-trapping dam includes silt-trapping dams respectively set at multiple inlets of a reservoir 1, a water-retaining dam 6 set on the reservoir 1, and a silt collection well 7 set on the downstream side of the water-retaining dam 6; multiple silt-trapping dams located on the same side of the reservoir 1 are connected in series by silt discharge channels or silt discharge tunnels, and the silt-trapping dam at the end is connected to the silt collection well 7 by a silt discharge channel or silt discharge tunnel; it also includes a diversion tunnel 16, which connects the reservoir 1 with the river channel downstream of the water-retaining dam 6.

[0054] If the geological conditions between two adjacent sand-retaining dams are Class IV or Class V, and the height difference between the two adjacent sand-retaining dams is less than 3 times the width of the sand-drainage tunnel, then the two sand-retaining dams shall be connected by a sand-drainage channel.

[0055] If the geological conditions between two adjacent sand-retaining dams are Class I, Class II, or Class III, and the elevation difference between the two adjacent sand-retaining dams is greater than or equal to three times the width of the sand-discharge tunnel, then the two sand-retaining dams shall be connected by a sand-discharge tunnel.

[0056] If the geological conditions between the end sand-blocking dam and the sand-collecting well 7 are Class IV or Class V, and the height difference between the end sand-blocking dam and the sand-collecting well is less than 3 times the width of the sand-discharge tunnel, then the end sand-blocking dam and the sand-collecting well 7 shall be connected by a sand-discharge channel.

[0057] If the geological conditions between the end sand-blocking dam and the sand-collecting well 7 are Class I, Class II, or Class III, and the elevation difference between the end sand-blocking dam and the sand-collecting well is ≥ 3 times the width of the sand-discharge tunnel, then the end sand-blocking dam and the sand-collecting well 7 shall be connected by a sand-discharge tunnel.

[0058] Specifically, in this embodiment, there are four silt-trapping dams, which are respectively set at the four inlets on the same side of the reservoir 1, namely the first silt-trapping dam 2, the second silt-trapping dam 3, the third silt-trapping dam 4, and the fourth silt-trapping dam 5. The first silt-trapping dam 2, the second silt-trapping dam 3, the third silt-trapping dam 4, and the fourth silt-trapping dam 5 can be made of rockfill or concrete.

[0059] Combination Figure 1The diagram shows the overall layout of a first scheme for a sediment-trapping dam in a water conservancy project. This scheme is applicable when the height difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3 is less than three times the width of the sediment-drainage tunnel, and the geological conditions are Class IV or V. In this case, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by a first sediment-drainage channel 8. When the height difference between the second sediment-trapping dam 3, the third sediment-trapping dam 4, and the fourth sediment-trapping dam 5 is greater than or equal to three times the width of the sediment-drainage tunnel, and the geological conditions are Class I, II, or III, it is not suitable to construct a sediment-drainage channel. Therefore, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by a second sediment-drainage tunnel 13, and the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by a third sediment-drainage tunnel 14. When the height difference between the fourth sediment-trapping dam 5 and the sediment collection well 7 is less than three times the width of the sediment-drainage tunnel, the overburden layer is relatively thin, and the geological conditions are Class IV or V, the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by a fourth sediment-drainage channel 11.

[0060] Furthermore, Figure 2 The diagram shows the overall layout of a second scheme for a sediment-trapping dam in a water conservancy project. This scheme is suitable for first sediment-trapping dam 2, second sediment-trapping dam 3, and third sediment-trapping dam 4 where the geological conditions are Class IV or V, and the elevation difference is less than 3 times the width of the sediment discharge tunnel. Therefore, first sediment-trapping dam 2 and second sediment-trapping dam 3 are connected by first sediment discharge channel 8, and second sediment-trapping dam 3 and third sediment-trapping dam 4 are connected by second sediment discharge channel 9. The elevation difference between third sediment-trapping dam 4 and fourth sediment-trapping dam 5 is greater than or equal to 3 times the width of the sediment discharge tunnel, and the geological conditions are Class I, II, or III. Therefore, third sediment-trapping dam 4 and fourth sediment-trapping dam 5 are connected by third sediment discharge tunnel 14. The elevation difference between fourth sediment-trapping dam 5 and sediment collection well 7 is greater than or equal to 3 times the width of the sediment discharge tunnel, and it is not suitable to construct a sediment discharge channel. Therefore, fourth sediment discharge tunnel 15 is used for connection.

[0061] Furthermore, Figure 3 The diagram shows the overall layout of the third scheme of a water conservancy project's sediment-trapping dam. This scheme is suitable for situations where the geological conditions between the first sediment-trapping dam 2, the second sediment-trapping dam 3, the third sediment-trapping dam 4, and the fourth sediment-trapping dam 5 are Class IV or V, and the elevation difference is less than 3 times the width of the sediment discharge tunnel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge channel 8, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge channel 9, and the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third sediment discharge channel 10. The elevation difference between the fourth sediment-trapping dam 5 and the sediment collection well 7 is greater than or equal to 3 times the width of the sediment discharge tunnel, making it unsuitable for constructing a sediment discharge channel. Therefore, the fourth sediment discharge tunnel 15 is used for connection.

[0062] Furthermore, Figure 4The diagram shows the overall layout of the fourth scheme of a water conservancy project's silt-trapping dam. This scheme is applicable when the height difference between the first silt-trapping dam 2, the second silt-trapping dam 3, the third silt-trapping dam 4, the fourth silt-trapping dam 5, and the sand collection well 7 is less than three times the width of the sand discharge tunnel, the overburden layer is relatively thin, and the geological conditions are poor, classified as Class IV or Class V. Therefore, the first silt-trapping dam 2 and the second silt-trapping dam 3 are connected by the first sand discharge channel 8, the second silt-trapping dam 3 and the third silt-trapping dam 4 are connected by the second sand discharge channel 9, the third silt-trapping dam 4 and the fourth silt-trapping dam 5 are connected by the third sand discharge channel 10, and the fourth silt-trapping dam 5 and the sand collection well 7 are connected by the fourth sand discharge channel 11.

[0063] Furthermore, Figure 5 The diagram shows the overall layout of scheme 5 for a sediment-trapping dam in a water conservancy project. This scheme is suitable when the elevation difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3 is less than three times the width of the sediment-drainage tunnel, and the geological conditions are poor, classified as Class IV or V. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by a first sediment-drainage channel 8. When the elevation difference between the second sediment-trapping dam 3 and the third sediment-trapping dam 4 is larger, greater than or equal to three times the width of the sediment-drainage tunnel, and the geological conditions are relatively good, classified as Class I, II, or III, it is not suitable to construct a sediment-drainage channel. Therefore, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by a first sediment-drainage channel 8. The third sand-retaining dam 4 and the fourth sand-retaining dam 5 are connected by the second sand-retaining tunnel 13; the height difference between the third sand-retaining dam 4 and the fourth sand-retaining dam 5 is small, less than 3 times the width of the sand-retaining tunnel, the overburden layer is thin, and the geological conditions are poor, classified as Class IV or V. Therefore, the third sand-retaining dam 4 and the fourth sand-retaining dam 5 are connected by the third sand-retaining channel 10; the height difference between the fourth sand-retaining dam 5 and the sand-collecting well 7 is large, greater than 3 times the width of the sand-retaining tunnel, and the geological conditions are good, classified as Class I, Class II, or Class III. It is not suitable to construct a sand-retaining channel. Therefore, the fourth sand-retaining dam 5 and the sand-collecting well 7 are connected by the fourth sand-retaining tunnel 15.

[0064] Furthermore, Figure 6 The diagram shows the overall layout of the sixth scheme for a sediment-trapping dam in a water conservancy project. This scheme is suitable for situations where the geological conditions of the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are Class IV or V, and the elevation difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3 is less than three times the width of the sediment discharge tunnel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge channel 8. The elevation difference between the second sediment-trapping dam 3, the third sediment-trapping dam 4, the fourth sediment-trapping dam 5, and the sediment collection well 7 is relatively large, greater than or equal to three times the width of the sediment discharge tunnel, making it unsuitable for constructing a sediment discharge channel. Therefore, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge tunnel 13, the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third sediment discharge tunnel 14, and the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by the fourth sediment discharge tunnel 15.

[0065] Furthermore, Figure 7The diagram shows the overall layout of Scheme 7 for a sediment-trapping dam in a water conservancy project. This scheme is suitable for situations where the height difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3, and between the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5, is less than three times the width of the sediment discharge tunnel, and the geological conditions are poor, classified as Class IV or V. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge channel 8, and the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third sediment discharge channel 10; the second sediment-trapping dam 3 and the third sediment-trapping dam 5 are connected by the third sediment discharge channel 10. The elevation difference between the four sand-retaining dams is relatively large, ≥ 3 times the width of the sand-discharging tunnel, and the geological conditions are relatively good, classified as Class I, II, or III. Therefore, it is not suitable to construct a sand-discharging channel. Thus, the second sand-retaining dam 3 and the third sand-retaining dam 4 are connected by the second sand-discharging tunnel 13. The elevation difference between the fourth sand-retaining dam 5 and the sand-collecting well 7 is less than 3 times the width of the sand-discharging tunnel, the overburden layer is relatively thin, and the geological conditions are relatively poor, classified as Class IV or V. Therefore, the fourth sand-retaining dam 5 and the sand-collecting well 7 are connected by the fourth sand-discharging channel 11.

[0066] Furthermore, Figure 8 The diagram shows the overall layout of scheme 8 for a sediment-trapping dam in a water conservancy project. This scheme is suitable for situations where the elevation difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3, and between the second sediment-trapping dam 3 and the third sediment-trapping dam 4, is less than three times the width of the sediment discharge tunnel, and the geological conditions are poor, classified as Class IV or V. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge channel 8, and the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge channel 9; the third sediment-trapping dam 4 and the... The elevation difference between the four sand-blocking dams 5 is relatively large, ≥ 3 times the width of the sand-drainage tunnel, and the geological conditions are relatively good, classified as Class I, II, or III, making it unsuitable for constructing a sand-drainage channel. Therefore, the third sand-blocking dam 4 and the fourth sand-blocking dam 5 are connected by the third sand-drainage tunnel 14. The elevation difference between the fourth sand-blocking dam 5 and the sand-collecting well 7 is less than 3 times the width of the sand-drainage tunnel, and the overburden layer is relatively thin, indicating poor geological conditions, classified as Class IV or V. Therefore, the fourth sand-blocking dam 5 and the sand-collecting well 7 are connected by the fourth sand-drainage channel 11.

[0067] Furthermore, Figure 9 The diagram shows the overall layout of Scheme 9 for a water conservancy project's sediment-trapping dam. This scheme is suitable for situations where the elevation difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3 is large (≥ 3 times the width of the sediment discharge tunnel), the geological conditions are relatively good (Class I, II, or III), and it is not suitable to construct a sediment discharge channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge tunnel 12. The elevation difference between the second sediment-trapping dam 3, the third sediment-trapping dam 4, the fourth sediment-trapping dam 5, and the sediment collection well 7 is less than 3 times the width of the sediment discharge tunnel, the geological conditions are relatively poor (Class IV or V). Therefore, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge channel 9, the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third sediment discharge channel 10, and the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by the fourth sediment discharge channel 11.

[0068] Furthermore, Figure 10 The diagram shows the overall layout of Scheme 10 for a sediment-trapping dam in a water conservancy project. This scheme is suitable when the elevation difference between the first sediment-trapping dam 2, the second sediment-trapping dam 3, and the third sediment-trapping dam 4 is large (≥ 3 times the width of the sediment discharge tunnel), the geological conditions are relatively good (Class I, II, or III), and it is not suitable to construct a sediment discharge channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge tunnel 12, and the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge tunnel 13. When the elevation difference between the third sediment-trapping dam 4, the fourth sediment-trapping dam 5, and the sediment collection well 7 is less than 3 times the width of the sediment discharge tunnel, the geological conditions are poor (Class IV or V), the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third sediment discharge channel 10, and the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by the fourth sediment discharge channel 11.

[0069] Furthermore, Figure 11 The diagram shows the overall layout of Scheme 11 for a water conservancy project's sediment-trapping dam. This scheme is suitable for situations where the elevation difference between the first sediment-trapping dam 2, the second sediment-trapping dam 3, the third sediment-trapping dam 4, and the fourth sediment-trapping dam 5 is large (≥ 3 times the width of the sediment discharge tunnel), the geological conditions are relatively good (Class I, II, or III), and it is not suitable to construct a sediment discharge channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge tunnel 12, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge tunnel 13, and the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third sediment discharge tunnel 14. The elevation difference between the fourth sediment-trapping dam 5 and the sediment collection well 7 is less than 3 times the width of the sediment discharge tunnel, the geological conditions are poor (Class IV or V), and therefore the fourth sediment discharge channel 11 is used to connect the fourth sediment-trapping dam 5 and the sediment collection well 7.

[0070] Furthermore, Figure 12 The diagram shows the overall layout of Scheme 12 for a water conservancy project's sediment-trapping dam. This scheme is suitable for situations where the elevation difference between the first sediment-trapping dam 2, the second sediment-trapping dam 3, the third sediment-trapping dam 4, the fourth sediment-trapping dam 5, and the sediment collection well 7 is large (≥ 3 times the width of the sediment discharge tunnel), the geological conditions are relatively good (Class I, II, or III), and it is not suitable to construct a sediment discharge channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge tunnel 12, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge tunnel 13, the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third sediment discharge tunnel 14, and the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by the fourth sediment discharge tunnel 15.

[0071] Furthermore, Figure 13The diagram shows the overall layout of Scheme 13 for a sediment-trapping dam in a water conservancy project. This scheme is suitable for situations where the elevation difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3, and between the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 is large (≥ 3 times the width of the discharge tunnel), and the geological conditions are relatively good (Class I, II, or III). In such cases, it is not suitable to construct a discharge channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first discharge tunnel 12, and the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third discharge tunnel 14. Conversely, the elevation difference between the second sediment-trapping dam 3 and the third sediment-trapping dam 4, and between the fourth sediment-trapping dam 5 and the sand collection well 7 is less than 3 times the width of the discharge tunnel, and the geological conditions are poor (Class IV or V). Therefore, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second discharge channel 9, and the fourth sediment-trapping dam 5 and the sand collection well 7 are connected by the fourth discharge channel 11.

[0072] Furthermore, Figure 14 The diagram shows the overall layout of Scheme 14 for a sediment-trapping dam in a water conservancy project. This scheme is suitable for situations where the elevation difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3, and between the fourth sediment-trapping dam 5 and the sediment collection well 7 is large (≥ 3 times the width of the discharge tunnel), and the geological conditions are relatively good (Class I, II, or III). In such cases, it is not suitable to construct a discharge channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first discharge tunnel 12, and the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by the fourth discharge tunnel 15. Conversely, the elevation difference between the second sediment-trapping dam 3, the third sediment-trapping dam 4, and the fourth sediment-trapping dam 5 is less than 3 times the width of the discharge tunnel, and the geological conditions are poor (Class IV or V). Therefore, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second discharge channel 9, and the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third discharge channel 10.

[0073] Furthermore, Figure 15 The diagram shows the overall layout of Scheme 15 for a sediment-trapping dam in a water conservancy project. This scheme is suitable for situations where the elevation difference between the first sediment-trapping dam 2 and the second sediment-trapping dam 3, the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5, and the fourth sediment-trapping dam 5 and the sediment collection well 7 is large (≥ 3 times the width of the drainage tunnel), and the geological conditions are relatively good (Class I, II, or III). In such cases, it is not suitable to construct a drainage channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first drainage tunnel 12, the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 are connected by the third drainage tunnel 14, and the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by the fourth drainage tunnel 15. The elevation difference between the second sediment-trapping dam 3 and the third sediment-trapping dam 4 is less than 3 times the width of the drainage tunnel, and the geological conditions are poor (Class IV or V). Therefore, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second drainage channel 9.

[0074] Furthermore, Figure 16The diagram shows the overall layout of Scheme 16 for a sediment-trapping dam in a water conservancy project. This scheme is suitable when the elevation difference between the first sediment-trapping dam 2, the second sediment-trapping dam 3, the third sediment-trapping dam 4, and the fourth sediment-trapping dam 5 and the sediment collection well 7 is large (≥ 3 times the width of the sediment discharge tunnel), and the geological conditions are relatively good (Class I, II, or III). In such cases, it is not suitable to construct a sediment discharge channel. Therefore, the first sediment-trapping dam 2 and the second sediment-trapping dam 3 are connected by the first sediment discharge tunnel 12, the second sediment-trapping dam 3 and the third sediment-trapping dam 4 are connected by the second sediment discharge tunnel 13, and the fourth sediment-trapping dam 5 and the sediment collection well 7 are connected by the fourth sediment discharge tunnel 15. However, when the elevation difference between the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5 is less than 3 times the width of the sediment discharge tunnel, and the geological conditions are poor (Class IV or V), the third sediment discharge channel 10 is used to connect the third sediment-trapping dam 4 and the fourth sediment-trapping dam 5.

[0075] Figures 1 to 16 All of them are the same type of water conservancy project with sand-trapping dams, the difference being that the sand-trapping dams are connected by sand-drainage channels or sand-drainage tunnels.

[0076] In this embodiment, the sand collection well 7 is located slightly to the left or right of the downstream side of the dam 6. The main purpose is to avoid affecting the dam's flood discharge and downstream structures. The diversion tunnel 16 is located on the right side of the dam 6 to divert water during the rainy season and create conditions for dry construction.

[0077] In this embodiment, the cross-section of the sand drainage channel is trapezoidal, with dimensions of: upper base 3m-3.5m, lower base 1.8m-2.0m, and height 1.5m-2.0m. These dimensions are determined based on the slope and the amount of sand flowing at the site. The sand drainage tunnel has a circular cross-section with a diameter of 1.5m-2.5m, its dimensions also determined based on the slope and the amount of sand flowing at the site.

[0078] Combination Figure 17 , Figure 18 As shown, the sand collection well 7 is a hollow cylindrical shape. Inside the sand collection well 7, a sand-retaining wall 19 is installed, dividing the sand collection well 7 into a water pool 17 and a sand-water mixing pool 18. A sand discharge channel or tunnel at the end of the sand-retaining dam connects to the sand-water mixing pool 18. Filter holes 20 are provided on the sand-retaining wall 19, and a drain outlet 21 is provided at the bottom of the water pool 17. A dredging ladder 22 is installed inside the sand collection well 7, with a slope of 1:0.8 to 1:1. The water pool 17 is used for water accumulation or drainage. The filter holes 20 separate water and sand; the sand remains in the sand-water mixing pool 18, while the water flows into the water pool 17 and is discharged through the drain outlet 21. In this embodiment, the size of the sand collection well 7 is determined according to the slope and the amount of sand flow on site. The recommended diameter is A+B=3.0~3.5m. The filter holes 20 are arranged in a rectangular shape. The height of the sand retaining wall 19 can be determined according to the actual sand capacity. The size of the filter holes 20 is 12~15mm.

[0079] On the other hand, combining Figure 20 As shown, this embodiment also provides a method for constructing the above-mentioned silt-trapping dam for water conservancy projects, including the following steps:

[0080] Step S1: Select the inlet and outlet positions of the diversion tunnel 16 and construct the diversion tunnel 16;

[0081] Step S2: When the diversion tunnel 16 is flowing, construct the water-blocking dam 6;

[0082] Step S3: Utilize the diversion tunnel 16 for flow passage, and construct sand-blocking dams at each inlet of reservoir 1 during the dry season;

[0083] Step S4: Construct a drainage channel or drainage tunnel between adjacent sand-retaining dams, and construct a drainage channel or drainage tunnel between the end sand-retaining dam and the sand collection well 7;

[0084] Step S5: Construct a sand collection well 7, and at the same time construct a dredging ladder 22 inside the sand collection well 7, with the dredging ladder 22 arranged on one bank of the water-blocking dam 6.

[0085] Furthermore, in step S3, the construction of the silt-trapping dam includes the following steps:

[0086] Step S301: Based on the geological survey results, draw detailed geological profiles of the area surrounding each inlet of Reservoir 1;

[0087] Step S302: Calculate the maximum sediment discharge and sediment accumulation at each inlet of Reservoir 1 during the flood season, determine the inlet where a sediment-blocking dam needs to be built, and construct a sediment-blocking dam at that inlet.

[0088] In step S4, when constructing a sand drainage channel or sand drainage tunnel, first determine the geological conditions between two adjacent sand-blocking dams and between the end sand-blocking dam and the sand collection well 7. At the same time, determine the elevation difference between two adjacent sand-blocking dams and between the end sand-blocking dam and the sand collection well 7. Based on the geological conditions and elevation differences, select whether to use a sand drainage channel or a sand drainage tunnel for connection.

[0089] It is worth noting that, Figures 1 to 16 When the fourth sand-trapping dam 5 and sand-collecting well 7 are connected by sand-drainage channel 11, it is necessary to adopt Figure 17 Option 1: Connecting the central sand-trapping dam with sand-collecting well 7; Figures 1 to 16 When the fourth sand-trapping dam 5 and the sand-collecting well 7 are connected by the sand-discharging tunnel 15, it is necessary to adopt... Figure 18 The second option is to connect the central sand-blocking dam with the sand-collecting well 7. The reason for this is that, based on local conditions, the sand-collecting well 7 should meet the needs of terrain and sand discharge as much as possible.

[0090] In addition, it is worth noting that although the present invention sets up 4 sand-blocking dams, the principle can be applied to the setting of 1, 2, 3...n sand-blocking dams in subsequent selections according to the sand discharge requirements. Any changes made based on this principle are within the scope of protection of this patent.

[0091] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A hydraulic engineering sand trap, characterized in that, It includes sand-blocking dams set at multiple water inlets of the reservoir (1), water-blocking dams (6) set on the reservoir (1), and sand collection wells (7) set on the downstream side of the water-blocking dams (6). Multiple sand-blocking dams located on the same side of the reservoir (1) are connected in series by sand-drainage channels or sand-drainage tunnels, and the sand-blocking dam at the end is connected to the sand collection well (7) by sand-drainage channels or sand-drainage tunnels. It also includes a diversion tunnel (16) that connects the reservoir (1) to the river channel downstream of the dam (6); If the geological conditions between two adjacent sand-retaining dams are Class IV or Class V, and the height difference between the two adjacent sand-retaining dams is less than 3 times the width of the sand-drainage tunnel, then the two sand-retaining dams shall be connected by a sand-drainage channel. If the geological conditions between two adjacent sand-retaining dams are Class I, Class II, or Class III, and the elevation difference between the two adjacent sand-retaining dams is ≥ 3 times the width of the sand-discharge tunnel, then the two sand-retaining dams shall be connected by a sand-discharge tunnel. If the geological conditions between the end sand-blocking dam and the sand-collecting well (7) are Class IV or Class V, and the height difference between the end sand-blocking dam and the sand-collecting well (7) is less than 3 times the width of the sand-discharge tunnel, then the end sand-blocking dam and the sand-collecting well (7) are connected by a sand-discharge channel. If the geological conditions between the end sand-blocking dam and the sand-collecting well (7) are Class I, Class II, or Class III, and the height difference between the end sand-blocking dam and the sand-collecting well (7) is ≥ 3 times the width of the sand-discharging tunnel, then the end sand-blocking dam and the sand-collecting well (7) are connected by a sand-discharging tunnel.

2. The sediment-trapping dam for water conservancy projects as described in claim 1, characterized in that: The sand collection well (7) is located on the left or right side downstream of the water-blocking dam (6).

3. The silt-trapping dam for water conservancy projects as described in claim 1, characterized in that, The cross-section of the sand drainage channel is trapezoidal, with the following dimensions: upper base 3m~3.5m, lower base 1.8m~2.0m, and height 1.5m~2.0m.

4. The silt-trapping dam for water conservancy projects as described in claim 1, characterized in that, The sand-drainage tunnel has a circular cross-section with a diameter of 1.5m to 2.5m.

5. The silt-trapping dam for water conservancy projects as described in claim 1, characterized in that, The sand collection well (7) is a hollow cylindrical shape. Inside the sand collection well (7) is a sand retaining wall (19), which divides the sand collection well (7) into a water pool (17) and a sand-water mixing pool (18). The sand discharge channel or sand discharge hole between the sand retaining dam at the end and the sand collection well (7) is connected to the sand-water mixing pool (18). A filter hole (20) is provided on the sand retaining wall (19), and a drain outlet (21) is provided at the bottom of the water pool (17). A dredging ladder (22) is provided inside the sand collection well (7), and the slope of the dredging ladder (22) is 1:0.8~1:

1.

6. The method for constructing a sediment-trapping dam for a water conservancy project as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: Select the inlet and outlet positions of the diversion tunnel (16) and construct the diversion tunnel (16). Step S2: When the diversion tunnel (16) is filled with water, a water-blocking dam (6) is built. Step S3: Use the diversion tunnel (16) to allow flow, and build sand-blocking dams at each inlet of the reservoir (1) during the dry season; Step S4: Construct a drainage channel or drainage tunnel between adjacent sand-blocking dams, and construct a drainage channel or drainage tunnel between the end sand-blocking dam and the sand collection well (7); Step S5: Construct a sand collection well (7), and at the same time construct a dredging ladder (22) inside the sand collection well (7), with the dredging ladder (22) arranged on one side of the water-blocking dam (6).

7. The construction method as described in claim 6, characterized in that, Step S3, when constructing the silt-trapping dam, includes the following steps: Step S301: Based on the geological survey results, draw detailed geological profiles of the area surrounding each inlet of the reservoir (1); Step S302: Calculate the maximum sand discharge and sediment accumulation at each inlet of the reservoir (1) during the flood season, determine the inlet where a sand-blocking dam needs to be set up, and build a sand-blocking dam at the inlet.

8. The construction method as described in claim 7, characterized in that, In step S4, when constructing a sand drainage channel or sand drainage tunnel, first determine the geological conditions between two adjacent sand-blocking dams and between the end sand-blocking dam and the sand collection well (7), and at the same time determine the elevation difference between two adjacent sand-blocking dams and between the end sand-blocking dam and the sand collection well (7). Based on the geological conditions and elevation differences, choose to connect the sand drainage channel or the sand drainage tunnel.

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