Hydropower engineering channel type debris flow prevention and control system

Abstract

The invention discloses a channel type debris flow prevention and control system for hydropower engineering, and belongs to the technical field of hydropower and water conservancy. The system comprises a drainage and guide mechanism, and a construction site, an earth and stone retaining dam, a silt stopping pool and a plurality of flexible retaining dams which are sequentially arranged in a channel from downstream to upstream, the upstream end of the drainage and guide mechanism penetrates through the earth and stone retaining dam and then is communicated with the silt stopping pool, the middle part of the drainage and guide mechanism is buried in the construction site, and the downstream end of the drainage and guide mechanism extends to the downstream of the construction site. The drainage mechanism is arranged to drain debris flow to replace a drainage groove in the prior art, and burying of the drainage mechanism has low requirements on geological conditions of the foundation, small work amount, low investment and short construction period.

Description

TECHNICAL FIELD

[0001] The present application relates to a water and electricity engineering ditch type debris flow prevention system, belonging to the technical field of water and electricity. BACKGROUND

[0002] At present, some of the water and electricity engineering in China are concentrated in the high mountain and canyon area of Tibet region, the geological conditions of which are complex, and the construction site is arranged in a tense manner. Many construction sites are arranged in the ditch on both sides. Most of the ditches in Tibet region are debris flow ditches. Debris flow has the characteristics of suddenness, fast flow rate, large flow, large material capacity and strong destructive power, which has a great impact on the arrangement of construction sites.

[0003] The Chinese patent document with the publication number CN107119624A discloses a prevention system for large-scale waste dump in debris flow ditch, which comprises a waste dump, a check dam, a sedimentation pool, a drainage channel and a blocking dam. The check dam is located in the upstream of the debris flow ditch, the sedimentation pool is located between the check dam and the blocking dam arranged transversely in the downstream, the drainage channel is located on one side of the waste dump and arranged along the edge of the waste dump, the inlet of the drainage channel is located on the top of the waste dump in the upstream, the outlet of the drainage channel is located on the top of the waste dump on the outside, and the inlet of the drainage channel is located on one side of the blocking dam and is truncated on the blocking dam. The debris flow can be smoothly discharged to a safe position through the waste dump, so as to ensure the stability and safety of the waste dump.

[0004] However, the drainage channel of the above-mentioned prevention system is arranged on one side of the waste dump and along the edge of the waste dump. The excavation, concrete pouring and support engineering of the drainage channel are large in amount, high in investment, long in construction period and high in foundation requirement. SUMMARY

[0005] To solve the above technical problems, the present application provides a water and electricity engineering ditch type debris flow prevention system.

[0006] The present application is realized by the following technical scheme: A water and electricity engineering ditch type debris flow prevention system, comprising a drainage mechanism, and a construction site, a soil and rock check dam, a sedimentation pool and a plurality of flexible check dams arranged in the ditch from downstream to upstream, the upstream end of the drainage mechanism is communicated with the sedimentation pool after passing through the soil and rock check dam, the middle part is buried in the construction site, and the downstream end extends to the downstream of the construction site.

[0007] The upstream section of the bottom surface of the sedimentation pool is excavated as a gentle slope with a longitudinal slope not greater than 10%, and the downstream section of the bottom surface of the sedimentation pool is excavated as a stepped shape.

[0008] The upstream end of each platform of the downstream section of the bottom surface of the sedimentation pool is inclined downward relative to the downstream section in the longitudinal direction of the ditch.

[0009] The water-retaining face of the earth-rock retaining dam is provided with a seepage prevention mechanism.

[0010] The seepage prevention mechanism comprises a geomembrane and a concrete seepage prevention wall, the geomembrane is arranged at the upper part of the water-retaining face of the earth-rock retaining dam, the concrete seepage prevention wall is arranged at the lower part of the water-retaining face of the earth-rock retaining dam and is connected with the geomembrane, and the bottom of the concrete seepage prevention wall is connected with a seepage prevention curtain that penetrates into the foundation.

[0011] The lower part of the water-retaining face of the earth-rock retaining dam is provided with a trash rack, the trash rack is made by welding a plurality of 20b-shaped I-beams, and the spacing between the 20b-shaped I-beams is not greater than 1 m. The inlet of the drainage mechanism is located at the inner side of the trash rack.

[0012] The drainage mechanism comprises a steel corrugated pipe, and the inlet, outlet and turning part of the steel corrugated pipe are fixed by piers.

[0013] Further, an emergency drainage mechanism is arranged, the upstream end of the emergency drainage mechanism penetrates through the earth-rock retaining dam and is arranged to communicate with the sedimentation pool at the upper part of the water-retaining face of the earth-rock retaining dam, and the downstream end of the emergency drainage mechanism communicates with the middle part of the drainage mechanism.

[0014] The emergency drainage mechanism comprises an emergency steel corrugated pipe, and the downstream end of the emergency steel corrugated pipe communicates with the middle part of the drainage mechanism through a tee joint.

[0015] The tee joint is fixed by a pier.

[0016] The beneficial effects of the present application are as follows: 1. The drainage mechanism is arranged to drain the debris flow, so as to replace the drainage groove in the prior art, the drainage mechanism has low requirements on the geological conditions of the foundation, small engineering quantity, low investment and short construction period.

[0017] 2. The large stones and trees in the channel are first intercepted by the plurality of flexible retaining dams, then the solid materials passing through the flexible retaining dams are effectively intercepted by the sedimentation pool, the sedimentation pool can accommodate the large stones in the debris flow under the design standard, then the stones are intercepted by the trash rack at the inlet of the steel corrugated pipe, so as to ensure that the steel corrugated pipe is not blocked, and then ensure that the steel corrugated pipe is unobstructed to drain the debris flow.

[0018] 3. The sedimentation pool is arranged at the upstream of the earth-rock retaining dam, the seepage prevention mechanism is arranged on the water-retaining face of the earth-rock retaining dam, and the emergency steel corrugated pipe is arranged at the upper part of the earth-rock retaining dam, when the steel corrugated pipe is blocked by the over-standard debris flow, the earth-rock retaining dam plays a role of retaining dam to retain the solid materials of the debris flow, at this time, the debris flow is drained through the emergency steel corrugated pipe, so as to realize the prevention and treatment of the over-standard debris flow and further ensure the safety of the construction site.

[0019] 4. The steel corrugated pipe is matched with the emergency steel corrugated pipe to realize the discharge of the over-standard debris flow, so that the steel corrugated pipe is fully utilized, and a pipe is not additionally buried to realize the discharge of the over-standard debris flow. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a plan layout of the present application; Figure 2 is a profile along the longitudinal direction of the channel of the present application; Figure 3 is a structural schematic view of the earth-rock dam of the present application; Figure 4 is a structural schematic view of the water-facing surface of the earth-rock dam of the present application; Figure 5 is a structural schematic view of the flexible dam of the present application; Figure 6 is an assembly view of the steel corrugated pipe, the emergency steel corrugated pipe, the tee joint and the pier of the present application.

[0021] In the figure: 1-flexible dam, 2-earth-rock dam, 3-steel corrugated pipe, 4-emergency steel corrugated pipe, 5-tee joint, 6-pier, 7-anti-seepage curtain, 8-geomembrane, 9-siltation pool, 10-concrete anti-seepage wall, 11-pollution barrier, 12-construction site, 13-discharge mechanism. DETAILED DESCRIPTION

[0022] The technical solutions of the present application are further described below, but the scope of protection is not limited to the description.

[0023] Example 1: According to the scale of the construction site 12, the design standard of debris flow prevention is determined, and the peak flow and the total amount of solid matter of a debris flow under the design standard are determined.

[0024] As shown in Figures 1 to 6 A channel-type debris flow prevention system for a hydropower project according to the present application includes a discharge mechanism 13 and, from downstream to upstream, a construction site 12, an earth-rock dam 2, a siltation pool 9 and multiple flexible dams 1 arranged in the channel in sequence. The upstream end of the discharge mechanism 13 is communicated with the siltation pool 9 after passing through the earth-rock dam 2, the middle part is buried in the construction site 12, and the downstream end extends to the downstream of the construction site 12.

[0025] The flexible dam 1 and the earth-rock dam are arranged to intercept debris flow, so as to replace the conventional rigid dam such as the grid dam, the screen dam, the comb dam and the permeable arch dam, the foundation requirement is low, the excavation and support engineering quantity of the foundation can be greatly reduced, the construction period and the engineering investment are saved, then the drainage mechanism 13 is arranged to drain the debris flow, so as to replace the drainage groove in the prior art, the drainage mechanism 13 is buried, the geological condition requirement of the foundation is low, the engineering quantity is small, the investment is low and the construction period is short.

[0026] The upstream section of the bottom surface of the siltation pool 9 is excavated as a gentle slope with a longitudinal slope not greater than 10%, and the downstream section of the bottom surface of the siltation pool 9 is excavated as a stepped shape.

[0027] The upstream end of each platform of the downstream section of the bottom surface of the siltation pool 9 is inclined downward relative to the downstream section in the longitudinal direction of the channel. The siltation pool 9 can effectively intercept the solid material passing through the flexible dam 1, can accommodate the large stones in the debris flow under the design standard, ensures that the steel corrugated pipe 3 is not blocked, and further ensures that the steel corrugated pipe 3 is unobstructed to drain the debris flow.

[0028] The water-facing surface of the earth-rock dam 2 is provided with a seepage prevention mechanism.

[0029] The seepage prevention mechanism comprises a geomembrane 8 and a concrete seepage prevention wall 10, the geomembrane 8 is arranged at the upper portion of the water-facing surface of the earth-rock dam 2, the concrete seepage prevention wall 10 is arranged at the lower portion of the water-facing surface of the earth-rock dam 2 and is connected with the geomembrane 8, and the bottom of the concrete seepage prevention wall 10 is connected with a seepage prevention curtain 7 which penetrates into the foundation. By arranging the geomembrane 8, the concrete seepage prevention wall 10 and the seepage prevention curtain 7, the seepage of the earth-rock dam 2 and the construction site 12 is ensured to be stable.

[0030] The lower portion of the water-facing surface of the earth-rock dam 2 is provided with a trash rack 11, the trash rack 11 is made of a plurality of 20b type I-beams which are welded, and the interval distance between the 20b type I-beams is not greater than 1m. The inlet of the drainage mechanism 13 is located at the inner side of the trash rack 11. The trash rack 11 is arranged at the inlet of the steel corrugated pipe 3, so as to intercept the large stones through the trash rack 11, ensure that the steel corrugated pipe 3 is not blocked, and further ensure that the steel corrugated pipe 3 is unobstructed to drain the debris flow.

[0031] The drainage mechanism 13 comprises a steel corrugated pipe 3, the inlet, the outlet and the turning portion of the steel corrugated pipe 3 are respectively fixed by a pier 6. The steel corrugated pipe 3 is used to drain the debris flow, and the steel corrugated pipe 3 is fixed by the pier 6, so as to ensure that the steel corrugated pipe 3 is stable and safe in operation.

[0032] Further comprising an emergency drainage mechanism, the upstream end of the emergency drainage mechanism penetrates through the earth-rock dam 2 and penetrates out from the upper portion of the water-facing surface of the earth-rock dam 2 and communicates with the siltation pool 9, and the downstream end of the emergency drainage mechanism communicates with the middle portion of the drainage mechanism 13.

[0033] The emergency drainage mechanism comprises an emergency steel corrugated pipe 4, and a downstream end of the emergency steel corrugated pipe 4 is communicated with a middle part of the drainage mechanism 13 through a tee joint 5. The downstream end of the emergency steel corrugated pipe 4 is communicated with a middle part of the steel corrugated pipe 3 through the tee joint 5. The emergency steel corrugated pipe 4 is additionally arranged, and when the steel corrugated pipe 3 is blocked by the over-standard debris flow, the emergency steel corrugated pipe 4 still has the condition of draining the debris flow, and can ensure the safety and stability of the construction site 12. The steel corrugated pipe 3 and the emergency steel corrugated pipe 4 are connected through the tee joint 5, so that the length of the emergency steel corrugated pipe 4 is optimized, and the engineering investment is saved.

[0034] The tee joint 5 is fixed through a pier 6.

[0035] Embodiment two: The above water conservancy project channel type debris flow prevention system has been used in part of projects, and has good effect. The implementation case and process are as follows: In this example, the debris flow prevention of a channel of the RM project is taken as an example. The channel is a right bank branch ditch of the Lancang River, belongs to a high mountain landform of deep cutting structure erosion, and the terrain is steep in the whole basin. The gully is crisscrossed, and the overhang condition is developed, which provides conditions for the collection of loose solid sources of debris flow in the basin. The catchment area of the channel basin is 40.75km 3 , the main ditch is 13.01km long, the relative height difference is 3092m, the average longitudinal slope of the main ditch is 19.5%, and the overall channel trend is southwest-northeast.

[0036] The channel is a low-frequency rare medium-sized debris flow gully, the easy-to-occur degree is medium, and the development degree is developed. The safety grade standard of the debris flow disaster prevention engineering is four, the prevention standard is 20-year return period, the debris flow flow is 98.7m 3 / s, and the total amount of debris flow solid is about 55,000m 3 . After taking the debris flow prevention measures, the influence of the debris flow on the site can be eliminated, and the site can be used as a construction site. The specific implementation mode is as follows: 1. A flexible retaining dam 1 is arranged at each of positions about 540m and 340m upstream of the earth and stone retaining dam 2. The maximum heights of the two flexible retaining dams are 5m and 8m respectively, the axis lengths are 31m and 42m respectively, and the total storage capacity of the flexible retaining dam is about 60,000m 3 , which meets the condition of retaining the total amount of debris flow solid of 20-year return period.

[0037] 2. An earth-rock dam 2 is constructed downstream of the flexible retaining dam 1. The foundation elevation of the dam base is 2915.00m, the crest elevation is 2946.00m, the crest width is 5m, the upstream slope ratio is 1:2, the downstream slope ratio is 1:2, the maximum dam height is 31m, and the total length of the dam crest is approximately 69m. The dam is designed for a 20-year return period, corresponding to an upstream water level of 2940.00m. Considering the impact of excessive debris flow, the crest elevation of 2946.00m is adopted. The earth-rock dam 2 employs a seepage barrier wall 10 + composite geomembrane 8 + curtain grouting 7 for seepage prevention, ensuring the safety and stability of the earth-rock dam 2 and the construction site 12.

[0038] 3. An silt retention pond 9 is excavated upstream of the earth-rock dam 2. The lower part of the excavation is stepped, and the upper part is a gentle slope. The lower step is about 25m to 30m wide and about 100m long. The bottom of the upper gentle slope is about 20m to 25m wide and about 50m long. The silt retention pond 9 can effectively intercept solid materials passing through the flexible retaining dam 1 and ensure that the steel corrugated pipe 3 is not blocked.

[0039] 4. A corrugated steel pipe 3 is installed at the bottom of the earth-rock dam 2. The inlet of the corrugated steel pipe 3 is located upstream of the earth-rock dam 2, and the outlet is located downstream of the construction site 12. The axial length of the corrugated steel pipe 3 is about 580m, the diameter of the corrugated steel pipe 3 is 4.0m, and the maximum longitudinal slope is 9.63%. To ensure that the corrugated steel pipe 3 is not blocked, a trash rack 11 is installed at the inlet of the corrugated steel pipe. The trash rack 11 is made of 20b type I-beams, and the spacing between rows is 0.8m. To ensure the stable operation of the corrugated steel pipe 3, a pier 6 is installed at the bend of the corrugated steel pipe 3. The pier 6 is a cube with a side length of 0.8m made of concrete.

[0040] 5. An emergency corrugated steel pipe 4 is installed on the top of the earth-rock dam 2. The inlet of the emergency corrugated steel pipe 4 is located at the top of the earth-rock dam 2, and the outlet is connected to the middle of the corrugated steel pipe 3 via a tee 5. The diameter of the emergency corrugated steel pipe is 4.0m. When a debris flow exceeding the standard blocks the inlet of the corrugated steel pipe 3, the debris flow can be discharged normally through the emergency corrugated steel pipe 4. At this time, the earth-rock dam 2 plays the role of blocking the debris flow, with a storage capacity of approximately 14,000 m³. 3 It meets the requirement of blocking 12,000 cubic meters of solid material from a debris flow that occurs once every 50 years. 3 The conditions ensure the safe operation of the construction site 12.

Claims

1. A debris flow prevention system for hydropower engineering channels, characterized in that: It includes a drainage mechanism (13), and a construction site (12), an earth and rock dam (2), a silt retention pond (9) and several flexible dams (1) arranged sequentially from downstream to upstream in the ditch. The upstream end of the drainage mechanism (13) passes through the earth and rock dam (2) and connects with the silt retention pond (9). The middle part is buried in the construction site (12), and the downstream end extends to the downstream of the construction site (12).

2. The hydropower engineering channel-type debris flow prevention system as described in claim 1, characterized in that: The upstream section of the bottom surface of the siltation pond (9) is excavated as a gentle slope with a longitudinal slope of no more than 10%, and the downstream section of the bottom surface of the siltation pond (9) is excavated as a stepped shape.

3. The hydropower engineering channel-type debris flow prevention system as described in claim 2, characterized in that: The platforms of each platform in the downstream section of the bottom surface of the siltation pool (9) are inclined downward relative to the downstream section in the longitudinal direction of the channel.

4. The hydropower engineering channel-type debris flow prevention system as described in claim 1, characterized in that: The earth-rock dam (2) is equipped with a seepage prevention mechanism on its water-facing surface.

5. The hydropower engineering channel-type debris flow prevention system as described in claim 4, characterized in that: The seepage prevention mechanism includes a geomembrane (8) and a concrete seepage prevention wall (10). The geomembrane (8) is located on the upper part of the water-facing side of the earth-rock dam (2), and the concrete seepage prevention wall (10) is located on the lower part of the water-facing side of the earth-rock dam (2) and is connected to the geomembrane (8). The bottom of the concrete seepage prevention wall (10) is connected to a seepage prevention curtain (7) that extends into the foundation.

6. The hydropower engineering channel-type debris flow prevention system as described in claim 1, characterized in that: The earth-rock dam (2) has a trash rack (11) at the bottom of the water-facing side. The trash rack (11) is made of multiple 20b type I-beams welded together, and the spacing between the 20b type I-beams is no more than 1m. The inlet of the discharge mechanism (13) is located inside the trash rack (11).

7. The hydropower engineering channel-type debris flow prevention system as described in claim 1, characterized in that: The drainage mechanism (13) includes a corrugated steel pipe (3), and the inlet, outlet and turning point of the corrugated steel pipe (3) are fixed by piers (6).

8. The hydropower engineering channel-type debris flow prevention system as described in claim 1, characterized in that: It also includes an emergency drainage mechanism. The upstream end of the emergency drainage mechanism passes through the earth-rock dam (2) and exits from the upper part of the water-facing side of the earth-rock dam (2) to connect with the siltation pool (9). The downstream end of the emergency drainage mechanism is connected to the middle part of the drainage mechanism (13).

9. The hydropower engineering channel-type debris flow prevention system as described in claim 8, characterized in that: The emergency drainage mechanism includes an emergency corrugated steel pipe (4), and the downstream end of the emergency corrugated steel pipe (4) is connected to the middle part of the drainage mechanism (13) through a tee (5).

10. The hydropower engineering channel-type debris flow prevention system as described in claim 9, characterized in that: The tee (5) is fixed by a retaining block (6).

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