Anti-scour system for long-distance water conveyance canal and water return canal in desert area

Abstract

The invention relates to a water delivery canal in the technical field of scour prevention, in particular to a scour prevention system for a long-distance water delivery canal and a water return canal in a desert area. The channel comprises a hard channel and a soft channel; the hard channel is connected with the downstream end of the main body channel, and the hard channel adopts a hard structure to guide water flow to a low-terrain containing and discharging area for eliminating fall; the soft channel is arranged in the containing and discharging area and connected with the downstream end of the hard channel. The soft channel is of a flexible structure so as to eliminate residual energy of concentrated water flow. A soft and hard combined mode is adopted in the design process of the water recession channel, that is, a concrete structure is adopted to guide water flow to a low-terrain containing and discharging area far away from a main body channel, the fall is eliminated, a flexible gabion structure is adopted to eliminate residual energy of concentrated water flow, reduce the bottom flow speed and prevent local scouring, and the water recession channel is designed in a soft and hard combined mode. And the problem of traceability damage of the aeolian sand is solved.

Description

Technical Field

[0001] The invention relates to a water delivery channel in the technical field of anti-scouring, in particular to an anti-scouring system for a water return channel of a long-distance water delivery channel in a desert area. Background Art

[0002] According to the "Irrigation and Drainage Project Design Code": The design flow of the drainage channel at the end of the channel should not be less than 50% of the design flow at the end of the channel.

[0003] Therefore, long-distance water delivery channels need to be equipped with drainage channels. When arranging steep slopes, energy dissipation pools and other structures in drainage channels, they should be arranged in accordance with the actual terrain; there should be an appropriate outlet (depression) downstream of the drainage, and it should also be regulated; when arranging energy dissipation structures, the upstream should be smoothly discharged and the downstream should be fully energy dissipated to prevent downstream scour.

[0004] The project area in the desert area is desert aeolian sand. Since desert aeolian sand is relatively loose and has poor erosion resistance, it is very easy to be damaged by concentrated water flow. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the drainage channel is damaged and washed away due to a certain height difference between the end of the drainage channel and the ground of the discharge area, which causes the water flow to go back to the source and destroy the drainage channel.

[0006] To achieve the above purpose, a long-distance water conveyance channel retreat channel anti-scour system in desert areas is provided, which includes a main channel, a hard channel and a soft channel;

[0007] The hard channel is connected to the downstream end of the main channel, and the hard channel uses a hard structure to guide the water flow to the discharge area with lower terrain to eliminate the drop;

[0008] The soft channel is arranged in the discharge area and connected to the downstream end of the hard channel;

[0009] Wherein, the soft channel adopts a flexible structure to eliminate the residual energy of the concentrated water flow.

[0010] Preferably, the hard structure is a concrete structure.

[0011] Preferably, the flexible structure is a flexible gabion cage.

[0012] Preferably, the lining structure of the flexible gabion cage includes a thick gravel cushion layer, a thick local sand mortar, a cloth and a membrane, a thick cast-in-place concrete slab and a thick gabion cage arranged in sequence from bottom to top, wherein:

[0013] A thick gravel pad is used to provide foundation support and aid drainage.

[0014] Thick local sand mortar is used to enhance structural stability and help secure the sub-floor.

[0015] One cloth and one membrane usually refers to a layer of geotextile plus a layer of waterproof membrane, which is used to isolate the upper and lower layers of materials and prevent damage caused by moisture penetration.

[0016] Thick cast-in-place concrete slabs are used to increase overall strength and durability.

[0017] Thick gabion cages, as the outermost layer, directly face the water flow while allowing a certain amount of deformation to adapt to environmental changes without losing functionality.

[0018] In this scheme, the purpose of the hard channel is to guide the water flow to the discharge area with lower terrain to eliminate the energy generated by the height difference. The main function of the hard channel is to stabilize the water flow and prevent erosion problems caused by excessive flow rate; the soft channel uses a flexible structure to further disperse and absorb the remaining energy, thereby protecting the surrounding environment from the damage of high-speed water flow. Gabion stone cage is a mesh structure woven by metal wires, filled with stones or other hard materials, with good permeability and ability to adapt to deformation, which makes it very suitable for occasions such as deserts that require flexibility and durability.

[0019] In addition, due to the lack of vegetation cover in desert areas, the surface is very susceptible to erosion by water flow. Hard channels limit water flow in a fixed channel through a solid structure, avoiding direct impact of water flow on the surrounding sand, thereby effectively protecting the surface from erosion. Hard channels can provide a stable water delivery path to ensure that water flows in a predetermined direction. Once the water reaches a low-lying area, the flow rate slows down. At this time, gabion stone cages are used to further dissipate energy, which can more safely introduce water into the natural environment or for irrigation purposes.

[0020] As a further improvement of the technical solution, the hard channel includes a first steep slope, a first energy dissipation pool, a gentle slope, a second steep slope, and a second energy dissipation pool;

[0021] in:

[0022] The first section of the steep slope has a longitudinal slope of 1 / 6;

[0023] A first-level stilling pool is arranged downstream of the first steep slope;

[0024] After the first-level energy dissipation pool, a gentle slope section with a longitudinal slope of 1 / 1000 is arranged;

[0025] The second steep slope is arranged after the gentle slope;

[0026] A secondary energy dissipation pool is arranged downstream of the second steep slope.

[0027] In the above scheme, the main function of the first steep slope (longitudinal slope 1 / 6) is to quickly reduce the water level difference, so that the water can flow quickly from high places to low-lying areas. Therefore, choosing a steeper slope is to consume part of the potential energy as soon as possible, and at the same time, on the basis of the hard channel, it is ensured that there will be no serious scouring problems due to excessive flow rate; the first-level stilling pool immediately after the first steep slope is used to absorb and disperse most of the kinetic energy of the high-speed water flow brought by the steep slope, to prevent direct impact on downstream structures or the natural environment and cause damage. In addition, the stilling pool can also play a buffering role, making the water flow more stable and preparing for the subsequent gentle slope section.

[0028] After the first stilling basin, a very gentle slope is arranged, the purpose of which is to allow the water flow, which has slowed down and lost a lot of kinetic energy, to continue to move forward at a lower speed. This design helps to further stabilize the water flow, reduce any possible residual energy, and provide enough time and space for the silt carried in the water to settle down, avoiding the accumulation of these materials further downstream; then a steeper slope is introduced again, aiming to take advantage of the terrain to further lower the water level while maintaining an appropriate flow rate to ensure that the water flow does not stagnate.

[0029] Finally, another stilling basin is set after the second steep slope, and the presence of the secondary stilling basin ensures that even in extreme cases, no excessive energy is transferred to the soft channel.

[0030] As a further improvement of the technical solution, the soft channel includes a gabion stone cage diffusion section which is a flexible structure, and the gabion stone cage diffusion section is arranged behind the secondary stilling pool;

[0031] Among them, the longitudinal slope of the diffusion section of the gabion stone cage is 0, and a trapezoidal cross-section is adopted.

[0032] After the two-stage stilling pool, the water flow has lost most of its kinetic energy. At this time, entering a diffusion section without obvious slope can make the water flow more smoothly distributed, avoiding local erosion or scouring caused by sudden changes in flow rate, thus helping to maintain the stability of the water flow and reduce the impact on the downstream environment. Moreover, as a flexible structure, gabion stone cages are filled with stones or other materials. It not only provides sufficient strength to support the water flow and resist external pressure, but also its porous characteristics allow vegetation to grow, promoting the recovery and development of the ecological environment. In addition, the use of gabion stone cages can also help filter sediment and improve water quality.

[0033] In addition, because gabion stone cage is flexible, it can adapt well to irregular foundation conditions, and even if the ground settles or deforms slightly, it will not affect the integrity of the overall structure. This makes it very suitable for areas with complex geological conditions or prone to change, such as the edge of the desert.

[0034] Preferably, the bottom width of the gabion stone cage diffusion section gradually changes from 5.0m to 50.0m, which can effectively increase the water flow area, reduce the flow velocity, and form a wire mesh stone cage slope protection section with a slope of 1:3, that is, for every 1 unit increase in height, the horizontal extension is 3 units of length. This ensures sufficient anti-slip ability without being too steep to cause safety hazards.

[0035] As a further improvement of the technical solution, the straight section at the end of the soft channel and the arc section on the right are provided with flow side weirs to divert the water flow to the low-lying areas. The top elevation of the flow side weir is lower than the top platform of the flexible gabion stone cage, which allows the water to flow out smoothly at a lower position and reduces the pressure on the top platform.

[0036] Preferably, the downstream slope protection of the soft channel is connected with a local outlet extension protection section with a slope of 1:3.

[0037] Preferably, tooth walls are provided at the bottom of the rectangular grooves along the entire hard channel, the slope of the tooth walls is 1:1, and cushion beams are provided at the lower side of the tooth walls, and the length of the cushion beams is consistent with the width of the rectangular grooves.

[0038] The purpose of the above design is that the desert terrain is complex and changeable. Even in relatively flat areas, there may be local weak layers or different types of soils distributed in an interlaced manner. When these differentiated foundations are subjected to external loads (such as water flow impact), different degrees of settlement may occur. By setting a cushion beam under the tooth wall, the weight of the entire rectangular trough can be evenly distributed on a larger foundation, reducing the problem of structural stress concentration caused by uneven settlement. The length of the cushion beam is consistent with the width of the rectangular trough, ensuring good contact between the two and further enhancing the integrity of the structure.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] In the anti-scour system of the retreat channel of the long-distance water supply channel in the desert area, in order to ensure the safe operation of the main channel and the retreat channel and save project investment, the retreat channel adopts a combination of "soft and hard" methods in the design process for the desert aeolian sand, a soil with special engineering characteristics. That is, a concrete structure is used to divert the water flow to the discharge area with lower terrain far away from the main channel to eliminate the drop. A flexible gabion stone cage structure is used to eliminate the residual energy of the concentrated water flow, reduce the bottom flow velocity, prevent local scour, and solve the problem of traceability damage of aeolian sand. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the longitudinal section structure of the drainage channel lengthening project according to Example 1 of the present invention;

[0042] Figure 2The second schematic diagram of the longitudinal section structure of the drainage channel lengthening project according to the first embodiment of the present invention;

[0043] Figure 3 The third schematic diagram of the longitudinal section structure of the drainage channel lengthening project according to the first embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the plan structure of the drainage channel lengthening project according to Example 1 of the present invention;

[0045] Figure 5 This is a schematic diagram of the longitudinal section structure of the drainage channel lengthening project according to Embodiment 2 of the present invention;

[0046] Figure 6 This is the second schematic diagram of the longitudinal section structure of the drainage channel lengthening project according to Example 2 of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Headward erosion (also called upstream erosion or upstream erosion) occurs when water flows upstream along a stream bed or channel, removing material from the bottom and banks of the stream bed or channel. This phenomenon can spread rapidly because once started, the water flow will continue to erode and remove more material, exacerbating the damage.

[0049] Due to the characteristics of desert aeolian sand - loose and poorly resistant to erosion, this type of damage is very likely to occur under the action of concentrated water flow. In addition, the height difference between the end of the drainage channel and the ground in the discharge area will cause the water flow speed to increase, increasing the erosion force on the bottom and side walls of the channel.

[0050] To this end, a long-distance water transfer channel retreat channel anti-scour system is provided, which aims to extend and transform the retreat channel so that it has the ability to retreat water at a large flow rate for a long time, ensuring that the retreat function can be fully utilized under extraordinary circumstances. This is very necessary for improving the operational safety of open channel water transfer in deserts.

[0051] First embodiment, see Figure 1-Figure 4 As shown:

[0052] Figure 1The left side is connected to the original drainage channel energy dissipation pool 100. The anti-scour system consists of the first steep slope 300, the first energy dissipation pool 500, the gentle slope section 600, the second steep slope 800, the second energy dissipation pool 910 and the outlet gabion stone cage diffusion section 920, with a total length of 423.0m and a total drop of 27.36m.

[0053] The first section of the steep slope is 300 with a longitudinal slope of 1 / 6 and a length of 112.5m. The standard section has a net height of 3.0m, a net width of 3.0m, a bottom plate thickness of 0.5m, a side wall thickness of 0.3m to 0.5m, a step height of 0.625m, a length of 3.75m, and a total of 2 steps per section of the chute. The bottom of the first section of the steep slope is filled with a 60cm thick gravel cushion layer, and the upper part is poured with a 5cm thick C15 cushion layer of concrete.

[0054] The first-stage stilling pool 500 is arranged downstream of the first steep slope 300. The first-stage stilling pool 500 adopts C30F200W6 reinforced concrete structure, with a pool length of 37.5m, a pool depth of 3.5m, a net width of 5.5m, a net height of 7.5m, a bottom plate thickness of 1.3m, and a side wall thickness of 0.5m to 1.3m. The bottom of the first-stage stilling pool 500 is filled with a 60cm thick gravel cushion layer, and the upper part is poured with a 5cm thick C15 cushion concrete.

[0055] The first steep slope 300 constitutes a first gradient section 200 and a second gradient section 400, which are respectively connected to the original drainage channel stilling pool 100 and the first-level stilling pool 500. The first gradient section 200 and the second gradient section 400 are used for the transition of the sand backfill line B.

[0056] In order to ensure the smooth flow of turbulent water after energy dissipation, a gentle slope rectangular trough with a longitudinal slope of 1 / 1000 is arranged after the first energy dissipation pool 500, with a length of 37.5m, a net height of 4.0m, a net width of 5.5m, a bottom plate thickness of 1.0m, and a side wall thickness of 0.5m to 1.0m. A 60cm thick gravel cushion layer is filled at the bottom of the gentle slope section 600, and a 5cm thick C15 cushion layer concrete is poured on the top.

[0057] After the gentle slope section 600, the second steep slope 800 is arranged, with a longitudinal slope of 1 / 6 and a length of 90m. The structural dimensions of the second steep slope 800 are the same as those of the first steep slope 300. The bottom of the second steep slope 800 is filled with a 60cm thick cementitious sand cushion layer, and the upper part is poured with a 5cm thick C15 cushion concrete.

[0058] The second-level stilling pool 910 is arranged downstream of the second steep slope 800. The pool is 30.0m long, 3.0m deep, 5.0m wide, 6.5m high, with a bottom plate thickness of 1.2m and a side wall thickness of 0.5m to 1.2m. The bottom of the second-level stilling pool 910 is filled with a 60cm thick gelled sand cushion layer, and the upper part is poured with a 5cm thick C15 cushion concrete.

[0059] After the secondary energy dissipation pool 910, the gabion gabion diffusion section 920 is arranged, which is 70m long, with a longitudinal slope of i=0 and a trapezoidal cross-section. A 10cm thick cast-in-place concrete slab is laid under the gabion gabion. The bottom width of the gabion gabion diffusion section 920 gradually changes from 5.0m to 50.0m, with a net height of 3.5m, a slope of 1:3 (i.e. the wire gabion slope protection section 940), a 5.0m wide platform on the top of the embankment (i.e. the second wire gabion platform section 950), and a gabion gabion thickness of 30cm. After the gabion gabion diffusion section 920, the first wire gabion platform section 930 with a length of 30m is arranged, with a pool depth of 3.5m, a net width of 50m, a 5.0m platform on the top of the embankment, and a gabion gabion thickness of 30cm. The lining structure is "40cm thick gravel cushion + 3cm thick local sand mortar + one cloth and one membrane (membrane thickness 0.6mm) + 10cm thick cast-in-place concrete slab + 30cm thick gabion stone cage"; in addition, the wire mesh stone cage is protected to the elevation of the original ground line A (this section forms the tail section 960).

[0060] The second steep slope 800 constitutes the third gradient section 700 and the fourth gradient section 900, which are respectively connected to the gentle slope section 600 and the secondary energy dissipation pool 910. The third gradient section 700 and the fourth gradient section 900 are also used for the transition of the sand backfill line B.

[0061] Teeth walls are set at the bottom of the rectangular trough along the entire drainage channel. The tooth walls are 0.5m high, 0.5m wide, and have a slope of 1:1. Pad beams are set at the lower side of the tooth walls. The pad beams are 1.0m wide, 0.5m thick, and their length is consistent with the width of the rectangular trough in this section.

[0062] Second embodiment, see Figure 5 and Figure 6 As shown:

[0063] The drainage channel consists of a cast-in-place concrete channel section 970, a steep slope section 990, an energy dissipation basin section 992, an outlet diffusion section 993, a flow side weir section 995 and an outlet partial extension protection section 996, with a total length of 540.203m and a total drop of 11.86m.

[0064] The cast-in-place concrete channel section 970 adopts a trapezoidal cross-section, and the lining structure is C25F200W6 plain concrete. The channel bottom width is 4.0m, the clear height is 3.6m, the slope is 1:2.5, the bottom plate thickness is 10cm, and the side plate thickness is 9cm. The cast-in-place concrete channel section 970 has a longitudinal slope of 1 / 4000 and is 218.703m long, including 80m of straight section, 118.703m of turning section, and 20m of gradual section. The channel bottom width and slope of the gradual section remain unchanged, and the clear height gradually changes from 3.6m to 5.0m.

[0065] The steep slope section 990 adopts C30F200W6 reinforced concrete structure, with a longitudinal slope of 1 / 9 and a length of 135m. The standard chute section is 105m long, with a net width of 4.0m, a net height of 5.0m, a bottom plate thickness of 1.0m, and a side wall thickness of 0.5m to 1.0m; the gradient section is 30m long, with the net width of the chute gradually changing from 4.0m to 5.5m, the net height gradually changing from 5.0m to 8.0m, the bottom plate thickness gradually changing from 1.0m to 1.6m, and the side wall thickness gradually changing from 0.5m to 1.0m to 0.5m to 1.6m. The bottom of the steep slope section 990 is filled with a 60cm thick gravel cushion layer, and the upper part is poured with a 5cm thick C15 cushion layer concrete.

[0066] The stilling pool section 992 is set downstream of the steep slope section 990. The stilling pool section 992 adopts C30F200W6 reinforced concrete structure, with a pool length of 30.0m, a pool depth of 3.2m, a net width of 5.5m, a net height of 8.0m, a bottom plate thickness of 1.6m, and a side wall thickness of 0.5m to 1.6m. The bottom of the stilling pool section 992 is filled with a 60cm thick gravel cushion layer, and the upper part is poured with a 5cm thick C15 cushion concrete.

[0067] The steep slope section 990 constitutes the fifth gradient section 980 and the sixth gradient section 991, which are respectively connected to the cast-in-place concrete channel section 970 and the energy dissipation pool section 992. The fifth gradient section 980 and the sixth gradient section 991 are also used for the transition of the sand backfill line B.

[0068] After energy dissipation, the outlet diffuser 993 is arranged. The diffuser is 70m long, with a longitudinal slope of i=0. The bottom width of the diffuser changes from 5.5m to 50.0m, the net height changes from 4.8m to 3.5m, the slope is 1:3, and the top platform is 5.0m. A 30m long gabion stone cage square pool is arranged after the diffuser, with a pool depth of 3.5m, a net width of 50m, and a top platform of 5.0m. The lining structure is "40cm thick gravel cushion + 3cm thick local sand mortar + one cloth and one membrane + 10cm thick cast-in-place concrete slab + 30cm thick gabion stone cage". In combination with the actual terrain on site, a flow side weir 995 is set at the straight section at the end of the gabion stone cage square pool and the arc section on the right to divert the discharged water to the low-lying area. The top elevation of the flow side weir 995 is 1.5m lower than the top platform of the gabion stone cage, the weir top width is 9.5m, and the weir length is 49.132m; the downstream slope protection is connected with the local extension protection section 996 of the outlet with a slope of 1:3. The local extension protection section 996 of the outlet is 66.5m long in the direction of water flow and 72.5m long in the direction perpendicular to the water flow.

[0069] A tooth wall is set at the bottom of the gently sloping rectangular trough. The tooth wall is 0.5m high, 0.5m wide, and has a slope of 1:1. A pad beam is set at the lower side of the tooth wall. The pad beam is 1.0m wide and 0.5m thick, and its length is consistent with the width of the rectangular trough.

[0070] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A long-distance water delivery channel backwash channel anti-scouring system in desert areas, comprising a main channel, characterized in that: It also includes hard and soft channels; The hard channel is connected to the downstream end of the main channel, and the hard channel uses a hard structure to guide the water flow to the discharge area with lower terrain to eliminate the drop; The soft channel is arranged in the discharge area and connected to the downstream end of the hard channel; Wherein, the soft channel adopts a flexible structure to eliminate the residual energy of the concentrated water flow.

2. The anti-scouring system for the long-distance water supply channel in desert areas according to claim 1 is characterized in that: The hard structure is a concrete structure.

3. The anti-scouring system for the long-distance water supply channel in desert areas according to claim 1 is characterized in that: The flexible structure is a flexible gabion stone cage.

4. The anti-scouring system for the long-distance water supply channel in desert areas according to claim 3 is characterized in that: The lining structure of the flexible gabion stone cage comprises a thick gravel cushion layer, a thick local sand mortar, a cloth and a membrane, a thick cast-in-place concrete slab and a thick gabion stone cage which are sequentially arranged from bottom to top.

5. The anti-scouring system for the long-distance water conveyance channel in desert areas according to claim 1 or 2, characterized in that: The hard channel comprises a first steep slope (300), a first energy dissipation pool (500), a gentle slope section (600), a second steep slope (800), and a second energy dissipation pool (910); in: The first steep slope (300) has a longitudinal slope of 1 / 6; A first-level stilling pool (500) is arranged downstream of the first steep slope (300); After the first-level energy dissipation pool (500), a gentle slope section (600) with a longitudinal slope of 1 / 1000 is arranged; After the gentle slope section (600), the second steep slope section (800) is arranged; A secondary stilling pool (910) is arranged downstream of the second steep slope (800).

6. The anti-scouring system for the long-distance water supply channel in desert areas according to claim 3 or 4, characterized in that: The soft channel comprises a gabion gabion diffusion section (920) of a flexible structure, and the gabion gabion diffusion section (920) is arranged behind the secondary stilling pool (910); Among them, the longitudinal slope of the gabion stone cage diffusion section (920) is 0, and a trapezoidal cross-section is adopted.

7. The anti-scouring system for the long-distance water supply channel and the backwater channel in the desert area according to claim 6 is characterized in that: The bottom width of the gabion stone cage diffusion section (920) gradually changes from 5.0 m to 50.0 m, so as to form a wire gabion slope protection section (940) with a slope of 1:

3.

8. The anti-scouring system for the long-distance water supply channel in desert areas according to claim 3 is characterized in that: The end straight section of the soft channel and the right arc section are provided with a flow-through side weir (995) for directing water flow to a low-lying area. The top elevation of the flow-through side weir (995) is lower than the top platform of the flexible gabion stone cage.

9. The anti-scouring system for the long-distance water supply channel in desert areas according to claim 8 is characterized in that: The downstream slope protection of the soft channel is connected with an outlet local extension protection section (996) with a slope of 1:

3.

10. The anti-scouring system for the long-distance water supply channel and the backwater channel in the desert area according to claim 1 is characterized in that: The bottom of the rectangular trough along the entire hard channel is provided with a tooth wall with a slope of 1:

1. A cushion beam is provided at the lower side of the tooth wall, and the length of the cushion beam is consistent with the width of the rectangular trough.

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