Desert area long distance water delivery channel backwater channel anti-scour system

Abstract

The present application relates to the technical field of anti-scouring, in particular to a long-distance water delivery channel anti-scouring system for a desert area. The system comprises a hard channel and a soft channel. 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 a lower-lying discharge area to eliminate the fall. The soft channel is arranged in the discharge area and connected to the downstream end of the hard channel. The soft channel uses a flexible structure to eliminate the residual energy of the concentrated water flow. In the present application, the discharge channel adopts a combination of hard and soft structures in the design process. The water flow is guided to a discharge area away from the main channel and having a lower topography by using a concrete structure to eliminate the fall. A flexible gabion structure is used to eliminate the residual energy of the concentrated water flow, reduce the bottom flow rate, prevent local scouring, and solve the problem of aeolian sand backtracking damage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-scouring water delivery channel, in particular to a long-distance water delivery channel in desert area. BACKGROUND

[0002] According to the Design Specification for Irrigation and Drainage Engineering: the design flow of the channel end return channel should not be less than 50% of the design flow of the channel end.

[0003] Therefore, the long-distance water delivery channel needs to be provided with a return channel. When arranging the steep slope and the stilling basin and other structures, the return channel should be arranged in combination with the actual terrain; the downstream of the return channel should have a proper outlet (depression) and should also be regulated; when arranging the energy dissipation structure, the upstream should be smooth and the downstream should be fully energy dissipated to prevent downstream scouring.

[0004] The engineering area in the desert area is desert aeolian sand. Since the desert aeolian sand is relatively loose and has poor anti-scouring property, it is prone to source destruction under the action of concentrated water flow. SUMMARY

[0005] The purpose of the present application is to solve the problem of source destruction and destruction of the return channel caused by the difference in height between the end of the return channel and the ground of the discharge area.

[0006] To achieve the above purpose, a long-distance water delivery channel return channel anti-scouring system in a desert area is provided, which comprises a main channel and further comprises a hard channel and a soft channel.

[0007] The hard channel is connected with the downstream end of the main channel, the hard channel uses a hard structure to guide the water flow to the lower terrain discharge area, and is used for eliminating the difference in height.

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

[0009] The soft channel uses 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.

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

[0013] The thick sand gravel cushion layer is used to provide foundation support and help drainage.

[0014] The thick local sand mortar is used to enhance the structural stability and help fix the bottom layer.

[0015] One cloth one film generally refers to a layer of geotextile plus a layer of waterproof film, used to isolate the upper and lower materials and prevent water penetration damage.

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

[0017] Thick gabion stone cage as the outermost layer, directly facing the water flow, while allowing some deformation to adapt to environmental changes without losing function.

[0018] In this scheme, the hard channel is designed to guide the water flow to the lower terrain discharge area to eliminate the energy generated by the height difference. The main role of the hard channel is to stabilize the water flow and prevent erosion problems caused by excessive flow velocity; the soft channel uses flexible structures 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 net-like structure woven by metal wire, filled with stones or other hard materials, with good water permeability and deformation adaptation, which makes it very suitable for use in desert areas that require flexibility and durability.

[0019] In addition, due to the lack of vegetation coverage in desert areas, the ground surface is very susceptible to water erosion. The hard channel restricts the water flow in a fixed channel through a solid structure, avoiding direct impact of the water flow on the surrounding sand, thereby effectively protecting the ground surface from erosion, and the hard channel can provide a stable water delivery path to ensure the water flow in the predetermined direction. Once the water flow reaches the low-lying area, the flow velocity slows down, and the gabion stone cage is used to further dissipate energy, which can more safely guide the 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 primary stilling basin, a gentle slope section, a second steep slope, and a secondary stilling basin.

[0021] Wherein:

[0022] The first steep slope has a longitudinal slope of 1 / 6.

[0023] The first steep slope is arranged downstream of the primary stilling basin.

[0024] The gentle slope section with a longitudinal slope of 1 / 1000 is arranged after the primary stilling basin.

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

[0026] The secondary stilling basin is arranged downstream of the second steep slope.

[0027] In the above scheme, the first steep slope (longitudinal slope 1 / 6) mainly serves to quickly reduce the height difference of the water level, so that the water flow can quickly flow from high to low-lying areas. Therefore, a relatively steep slope is chosen to quickly dissipate part of the potential energy, while ensuring that the hard channel will not be severely eroded due to excessive flow rate. The first energy dissipating 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, preventing damage caused by direct impact on downstream structures or the natural environment. In addition, the energy dissipating pool also serves as a buffer, making the water flow more stable and preparing for the subsequent gentle slope section.

[0028] After the first energy dissipating pool, a very gentle slope section is arranged, which is designed to allow the water flow that has been slowed down and lost a lot of kinetic energy to continue moving forward at a lower speed. Such a design helps to further stabilize the water flow, reduce any remaining energy, and provides enough time and space for the sediment carried in the water to settle down, avoiding the accumulation of these substances in the downstream location; then a steeper slope is introduced again, aiming to further reduce the water level by taking advantage of the terrain, while maintaining an appropriate flow rate to ensure that the water flow does not stagnate.

[0029] Finally, another energy dissipating pool is set after the second steep slope, and the presence of the second energy dissipating pool ensures that even in extreme cases, excessive energy will not be transferred to the soft channel.

[0030] As a further improvement of the technical solution, the soft channel includes a gabion diffusion section that is a flexible structure, arranged after the second energy dissipating pool.

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

[0032] After being processed by the two energy dissipating pools, the water flow has lost most of its kinetic energy, and entering a diffusion section with no obvious slope can make the water flow more evenly distributed, avoiding local erosion or scouring problems caused by sudden changes in flow rate, thereby helping to maintain the stability of the water flow and reducing the impact on the downstream environment. Moreover, as a flexible structure, the gabion is filled with stones or other materials, which not only provides sufficient strength to support the water flow and resist external pressure, but also allows vegetation to grow due to its porous nature, promoting the recovery and development of the ecological environment. In addition, the use of gabions can also help to filter sediment and improve water quality.

[0033] Furthermore, since the gabion is flexible, it can well adapt to irregular ground conditions, and even slight subsidence or deformation of the ground will not affect the integrity of the overall structure. This makes it very suitable for use in areas with complex or easily changing geological conditions, such as desert edge zones.

[0034] As preferred, the bottom width of the gabion diffuser section gradually changes from 5.0 m to 50.0 m, so as to effectively increase the water passing area and reduce the flow velocity, and a lead wire gabion slope section with a slope of 1:3 is formed, that is, for each unit of height increase, the lateral extension is 3 units in length, so as to ensure sufficient anti-sliding capacity and not too steep to cause safety hazards.

[0035] As a further improvement of the technical solution, the over-flow side weir is arranged at the straight section and the right circular arc section of the soft channel end, for guiding the water flow to a low-lying area, and the weir top elevation is lower than the embankment top platform of the flexible gabion, so that the water flow can smoothly flow out at a lower position, reducing the pressure on the embankment top platform.

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

[0037] As preferred, the rectangular groove bottom of the whole hard channel is provided with a tooth wall, the tooth wall slope is 1:1, and a cushion beam is arranged at the lower side of the tooth wall, and the length of the cushion beam is consistent with the width of the rectangular groove.

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

[0039] Compared with the prior art, the beneficial effects of the present application are:

[0040] In the anti-scouring system of the long-distance water delivery channel in the desert area, in order to ensure the safe operation of the main channel and the water return channel and save engineering investment, for the soil body of desert aeolian sand with special engineering characteristics, the water return channel adopts a "soft and hard" combination in the design process, that is, a concrete structure is used to guide the water flow to a low-lying discharge area away from the main channel, so as to eliminate the difference, and a flexible gabion structure is used to eliminate the residual energy of the concentrated water flow, reduce the bottom flow velocity, prevent local scouring, and solve the problem of aeolian sand backtracking damage. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 Figure 1 is a schematic diagram of the longitudinal section structure of the water return channel of the embodiment 1 of the present application;

[0042] Figure 2Figure 3 is a longitudinal section structure diagram of the extension project of the water outlet channel of the first embodiment of the present application;

[0043] Figure 3 Figure 4 is a longitudinal section structure diagram of the extension project of the water outlet channel of the first embodiment of the present application;

[0044] Figure 4 Figure 5 is a plane structure diagram of the extension project of the water outlet channel of the first embodiment of the present application;

[0045] Figure 5 Figure 6 is a longitudinal section structure diagram of the extension project of the water outlet channel of the second embodiment of the present application;

[0046] Figure 6 Figure 7 is a longitudinal section structure diagram of the extension project of the water outlet channel of the second embodiment of the present application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0048] Source destruction (also known as reverse erosion or upstream erosion) refers to the phenomenon that water flow erodes in the upstream direction along the riverbed or channel, causing the material at the bottom of the riverbed or channel and the bank slope to be washed away. This phenomenon can quickly spread because once it starts, the water flow will continue to erode and carry away more material, thereby exacerbating the degree of destruction.

[0049] Due to the characteristics of desert aeolian sand, which is loose and poor in erosion resistance, under the action of concentrated water flow, this type of damage is prone to occur, and the difference in height between the end of the water outlet channel and the ground of the discharge area will cause the water flow to speed up, increasing the erosion force on the bottom and side wall of the channel.

[0050] Therefore, a desert area long-distance water conveying channel water outlet channel anti-erosion system is provided, which aims to extend the water outlet channel for reconstruction, so that the water outlet channel has the ability to discharge water for a long time and in large flow, and can fully play the water outlet function in emergency situations, which is very necessary for improving the operation safety of the desert open channel water conveying period.

[0051] The first embodiment, see Figures 1-4 as shown:

[0052] Figure 1The left side of the original water return channel energy dissipation basin 100 is connected with the first steep slope 300, the first energy dissipation basin 500, the gentle slope section 600, the second steep slope 800, the second energy dissipation basin 910 and the outlet gabion diffusion section 920, and the total length is 423.0 m and the total fall is 27.36 m.

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

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

[0055] The first steep slope 300 constitutes the first gradual change section 200 and the second gradual change section 400, which are connected with the original water return channel energy dissipation basin 100 and the first energy dissipation basin 500 respectively, and the first gradual change section 200 and the second gradual change section 400 are used for the transition of the sand backfill line B.

[0056] In order to ensure the smoothness of the turbulent water flow after energy dissipation, a gentle slope rectangular channel with a longitudinal slope of 1 / 1000 is arranged after the first energy dissipation basin 500, which has a length of 37.5 m, a net height of 4.0 m, a net width of 5.5 m, a bottom plate thickness of 1.0 m and a side wall thickness of 0.5 m to 1.0 m. The gentle slope section 600 is filled with a 60 cm thick sand gravel cushion layer at the bottom and a 5 cm thick C15 cushion layer concrete at the upper part.

[0057] The second steep slope 800 is arranged behind the gentle slope section 600, has a longitudinal slope of 1 / 6 and a length of 90 m, and the structure size of the second steep slope 800 is consistent with that of the first steep slope 300. The second steep slope 800 is filled with a 60 cm thick cement sand cushion layer at the bottom and a 5 cm thick C15 cushion layer concrete at the upper part.

[0058] The second energy dissipation basin 910 is arranged downstream of the second steep slope 800, has a length of 30.0 m, a depth of 3.0 m, a net width of 5.0 m, a net height of 6.5 m, a bottom plate thickness of 1.2 m and a side wall thickness of 0.5 m to 1.2 m. The second energy dissipation basin 910 is filled with a 60 cm thick cement sand cushion layer at the bottom and a 5 cm thick C15 cushion layer concrete at the upper part.

[0059] A gabion diffuser section 920 is arranged behind the secondary stilling basin 910, with a length of 70 m, a longitudinal slope i = 0, a trapezoidal cross section, and a 10 cm thick cast-in-place concrete slab laid under the gabion. The bottom width of the gabion diffuser section 920 gradually changes from 5.0 m to 50.0 m, with a net height of 3.5 m, a slope of 1:3 (i.e., the wire mesh gabion slope protection section 940), a dike top platform width of 5.0 m (i.e., the second wire mesh gabion platform section 950), and a gabion thickness of 30 cm. A first wire mesh gabion platform section 930 with a length of 30 m is arranged behind the gabion diffuser section 920, with a pool depth of 3.5 m, a net width of 50 m, a dike top platform of 5.0 m, and a gabion thickness of 30 cm. The lining structure is “40 cm thick sand gravel cushion + 3 cm thick local sand mortar + one cloth and one film (film thickness 0.6 mm) + 10 cm thick cast-in-place concrete slab + 30 cm thick gabion”; in addition, the wire mesh gabion protection is 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 gradual change section 700 and the fourth gradual change section 900, which are connected with the gentle slope section 600 and the secondary stilling basin 910, respectively. The third gradual change section 700 and the fourth gradual change section 900 are also used for the transition of the sand backfill line B.

[0061] The tooth wall is arranged at the bottom of the rectangular channel of the entire drainage channel, with a height of 0.5 m, a width of 0.5 m, and a slope of 1:1. A cushion beam is arranged under the tooth wall, with a width of 1.0 m, a thickness of 0.5 m, and a length consistent with the width of the rectangular channel of the section.

[0062] The second embodiment, as shown in Figure 5 and Figure 6 The second embodiment, as shown in

[0063] The drainage channel is composed of a cast-in-place concrete channel section 970, a steep slope section 990, a stilling basin section 992, an outlet diffuser section 993, a flow side weir section 995, and a local outlet extension protection section 996, with a total length of 540.203 m and a total fall of 11.86 m.

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

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

[0066] The steep slope section 990 is filled with 60 cm thick sand gravel cushion at the bottom and 5 cm thick C15 cushion concrete at the upper part.

[0067] The steep slope section 990 constitutes the fifth gradual change section 980 and the sixth gradual change section 991, which are connected with the cast-in-situ concrete channel section 970 and the stilling basin section 992 respectively, and the fifth gradual change section 980 and the sixth gradual change section 991 are also used for the transition of the sand backfill line B.

[0068] The outlet diffusion section 993 is arranged after the energy dissipation, has length 70 m, longitudinal slope i=0, diffusion section bottom width gradually changing from 5.5 m to 50.0 m, net height gradually changing from 4.8 m to 3.5 m, side slope 1:3, and embankment top platform 5.0 m. A square Gabion stone cage pool with length 30 m, pool depth 3.5 m, net width 50 m, and embankment top platform 5.0 m is arranged after the diffusion section. The lining structure is “40 cm thick sand gravel cushion+3 cm thick local sand mortar+one cloth one film+10 cm thick cast-in-situ concrete plate+30 cm thick Gabion stone cage”. In combination with the actual terrain, the overflow side weir 995 is arranged at the terminal straight section and the right side circular arc section of the Gabion stone cage square pool to guide the discharged water flow to the low-lying place, the weir top elevation of the overflow side weir 995 is 1.5 m lower than the Gabion stone cage embankment top platform, the weir top width is 9.5 m, and the weir length is 49.132 m; the downstream protection slope is connected with the outlet local extension protection section 996 in a 1:3 slope, the outlet local extension protection section 996 has length 66.5 m along the water flow direction and length 72.5 m perpendicular to the water flow direction.

[0069] The tooth wall with height 0.5 m, width 0.5 m, and slope 1:1 is arranged at the bottom of the gentle slope rectangular channel, and the cushion beam with width 1.0 m and thickness 0.5 m is arranged at the lower side of the tooth wall, and the length of the cushion beam is consistent with the width of the rectangular channel.

[0070] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A non-erosion system for a desert region long distance water conveyance canal return channel, comprising a main body channel, characterized in that, The hard channel and the soft channel are further included; The hard channel is connected with the downstream end of the main channel, and the hard channel adopts a hard structure to guide the water flow to a lower terrain area for water discharge, so as to eliminate the drop; The soft channel is arranged in the water discharge area and connected with the downstream end of the hard channel; The soft channel adopts a flexible structure to eliminate the residual energy of the concentrated water flow; The hard channel includes a first steep slope (300), a first energy dissipater (500), a gentle slope section (600), a second steep slope (800), and a second energy dissipater (910). The first steep slope (300) has a longitudinal slope of 1 / 6, and the bottom of the first steep slope (300) is filled with a 60cm-thick sand gravel cushion layer and the upper part is poured with a 5cm-thick C15 cushion layer concrete. The first energy dissipater (500) is arranged downstream of the first steep slope (300), and the bottom of the first energy dissipater (500) is filled with a 60cm-thick sand gravel cushion layer and the upper part is poured with a 5cm-thick C15 cushion layer concrete. The gentle slope section (600) with a longitudinal slope of 1 / 1000 is arranged after the first energy dissipater (500) for first energy dissipation, and the bottom of the gentle slope section (600) is filled with a 60cm-thick sand gravel cushion layer and the upper part is poured with a 5cm-thick C15 cushion layer concrete. The second steep slope (800) is arranged after the gentle slope section (600), and the bottom of the second steep slope (800) is filled with a 60cm-thick cemented sand cushion layer and the upper part is poured with a 5cm-thick C15 cushion layer concrete. The second energy dissipater (910) is arranged downstream of the second steep slope (800), and the bottom of the second energy dissipater (910) is filled with a 60cm-thick cemented sand cushion layer and the upper part is poured with a 5cm-thick C15 cushion layer concrete. The hard structure is a concrete structure. The flexible structure is a flexible gabion. The lining structure of the flexible gabion includes, from bottom to top, a sand gravel cushion layer, local sand mortar, a cloth and a membrane, a cast-in-place concrete slab, and a gabion. The soft channel includes a gabion diffusion section (920) of a flexible structure, which is arranged after the second energy dissipater (910).

2. The erosion control system for desert region long distance water conveyance channel outlet channel according to claim 1, characterized in that, The longitudinal slope of the gabion diffusion section (920) is 0, and a trapezoidal cross section is adopted. The bottom width of the gabion diffusion section (920) gradually changes from 5.0m to 50.0m to form a lead wire gabion slope protection section (940) with a slope of 1:

3.

3. The erosion control system for desert region long distance water conveyance channel outlet channel according to claim 2, characterized in that, An overflow side weir (995) is arranged at the end of the straight section and the right circular arc section of the soft channel, which is used to guide the water flow to a low-lying area, and the weir top elevation of the overflow side weir (995) is lower than the embankment top platform of the flexible gabion.

4. The erosion control system of claim 1, wherein, The downstream slope protection of the soft channel is connected with an outlet local extension protection section (996) with a slope of 1:

3.

5. The erosion control system for the outfall of long distance water conveyance channels in desert regions according to claim 4, characterized in that, The rectangular groove bottom of the hard channel is provided with a tooth wall with a slope of 1:1, and a cushion beam is arranged at the lower side of the tooth wall with a length consistent with the width of the rectangular groove.

6. The erosion control system of claim 1, wherein, ​

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