Construction method suitable for adding waterproof material to original channel

Abstract

The invention relates to the field of hydraulic engineering construction, in particular to a construction method suitable for adding waterproof materials to an original channel. According to the construction method, different base surface treatment methods are adopted for different parts of an original canal, different waterproof treatments are carried out according to the water seepage importance degrees of the different parts, and the construction method mainly comprises the steps of canal bottom treatment, mortar leveling, waterproof geomembrane laying, corner treatment, surface layer steel bar installation, concrete pouring, side wall treatment and the like. The overall waterproof effect is good, channel leakage is effectively avoided, and the guarantee effect on embankment stability and channel surrounding road and building stability is achieved.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering construction, specifically to a method for adding waterproofing to existing channels. Background Technology

[0002] Current waterproofing methods involve using waterproof coatings or waterproof membranes for waterproofing.

[0003] (1) Waterproof membrane construction method 1) Process Flow Surface preparation → Apply primer → Lay additional layer of waterproof membrane → Hot melt application of waterproof membrane → Membrane termination 2) Construction method Base cleaning: Clean the surface of the base layer of debris, dust, etc., to ensure that the base layer is flat and clean.

[0004] Apply the primer: Apply the primer evenly to the substrate surface, ensuring even coverage and avoiding any missed areas. The next step can only be carried out after the primer has dried completely.

[0005] Apply an additional layer of waterproof membrane: Apply an additional layer of waterproof membrane to corners, pipe roots, and other areas. The width of the additional layer should meet the design requirements, generally not less than 250mm on each side. Use the hot-melt method to firmly bond the additional layer of membrane to the substrate, ensuring no hollow areas or curling edges.

[0006] Hot-melt application of waterproof membrane: Based on the slope of the drainage channel and the direction of membrane application, begin laying the membrane from the lowest point of the roof. The membrane should be laid flat and straight, without twisting or wrinkling. Use a hot-melt spray gun to heat the bottom surface of the membrane and the substrate. Once the membrane surface is hot-melted, immediately roll the membrane and press it firmly to adhere to the substrate. The overlap width of the membrane should meet the design requirements: the overlap width on the long side should be no less than 80mm, and the overlap width on the short side should be no less than 100mm. The short side overlaps of adjacent membrane rolls should be staggered by no less than 500mm.

[0007] Roll material termination treatment: Roll material terminations should be securely fixed and tightly sealed. Corner roll material terminations should be secured with metal strips and sealed with sealant. Roll material terminations near pipes and other surfaces should be sealed with sealant and reinforced with an additional layer.

[0008] (2) Waterproof coating construction method 1) Process Flow Surface cleaning → Applying primer → Applying waterproof coating 2) Construction method Base cleaning: Clean the surface of the base layer of debris, dust, etc., to ensure that the base layer is flat and clean.

[0009] Apply primer: Apply primer evenly to the substrate surface, and apply waterproof coating only after it dries.

[0010] Apply waterproof coating: Apply waterproof coating to the floor and walls according to design requirements. The coating should be applied evenly, without any missed areas, and the thickness should meet design requirements. Generally, the thickness of the waterproof coating on the floor should not be less than 1.5mm, and the height of the waterproof coating on the walls should not be less than 1800mm.

[0011] Current waterproofing methods are only suitable for applying waterproof coatings or membranes to surfaces in good condition with high flatness. However, existing canal surfaces often have various defects and are chronically damp, making them unsuitable for waterproof membrane or coating application. Furthermore, due to the large volume and rapid flow of water in canals, the continuous impact of water flow significantly reduces the seepage prevention effect of waterproof membranes or coatings, often failing to meet waterproofing requirements.

[0012] my country has numerous water conservancy projects, with canals crisscrossing the entire country. Even a tiny leak in a canal can cause it to grow and eventually lead to catastrophic accidents such as dam breaches. Therefore, the seepage prevention construction of existing canals is of particular importance.

[0013] This construction method addresses the shortcomings of the aforementioned methods by employing a waterproofing method suitable for channels with high humidity, poor original surface conditions, or even damage. After construction, it can effectively prevent water leakage from the channel, and the completed channel can withstand the adverse effects of continuous water flow. Summary of the Invention

[0014] To address the problems of existing technologies, this invention provides a method for adding waterproofing to existing channels. It is particularly suitable for waterproofing various types of water channels, providing a method for adding waterproofing to old channels.

[0015] To achieve the above objectives, the present invention adopts the following technical solution: A method for installing waterproofing on existing channels includes the following steps: (1) Remove brush bristles from the side wall Mix salt, baking soda, dish soap and water, spray the mixture onto the side wall and scrub it thoroughly with a wire brush; (2) Dredging and flushing of the canal bottom The excavator bucket is lowered to the bottom of the canal, and the silt at the bottom of the canal is shoveled into the excavator bucket by hand using a flat-headed shovel. It is then loaded into a dump truck and transported to the treatment plant for processing. Next, a small hammer is used to hammer the hollow, warped, and rotten concrete at the bottom of the canal, and it is shoveled into the excavator bucket along with the silt. Finally, the side walls and bottom plate are washed together with a high-pressure water gun. (3) Remove the bottom end of the canal To ensure a smooth connection between the bottom plate of the newly waterproofed section of the channel and the existing channel, the joint of the section to be treated is chiseled away, with the chiseling height being approximately 10cm, the same as the height of the new channel. First, a lime line is sprinkled at the end of the channel to be waterproofed, then an electric cutter is used to cut along the lime line, and then a pneumatic pick or electric hammer is used to chisel away the section along the slope. (4) Mixing of acrylic emulsion mortar To prepare acrylic emulsion mortar, first dry mix the cement and sand evenly, then add the acrylic emulsion and mix evenly, then add water. Wrap the mixed mortar with plastic sheeting, and after pre-shrinking, take a ball by hand and knead it for later use. (5) Apply acrylic emulsion waterproof mortar: For filling the side wall with acrylic emulsion waterproof mortar, apply a layer of acrylic emulsion waterproof cement slurry evenly on the pre-washed base surface. After about 15 minutes, start applying acrylic emulsion waterproof mortar, compact and smooth the acrylic emulsion waterproof mortar layer, cover it after 2 hours, and spray water for curing after 8 hours. (6) Cement mortar leveling of the bottom slab of the water channel Use cement mortar with the same mix ratio as the bottom slab of the canal to fill and level any uneven areas on the bottom slab of the canal, and then smooth the surface. (7) Waterproof geotextile laying The waterproof geotextile is laid on the bottom slab of the channel and is folded in half at the corner where the bottom slab meets the side wall to prevent cracking. The waterproof geotextile is made by adding the width of the channel bottom to the width of the fabric after folding it in half on both sides. When laying it, it is laid in full along the width of the channel, from one end of the channel to be treated to the other end, and the geotextile is folded in half at the end. During the laying of waterproof geotextile, the contact points of different waterproof geotextiles are overlapped and sewn together. The waterproof geotextile downstream of the channel water flow direction is placed below the upstream geotextile and overlapped and welded using qualified special welding equipment. (8) Corner treatment First, a steel plate is attached to the side wall, close to the fold of the waterproof geotextile but not overlapping it. The steel plate is then fixed to the side wall with expansion bolts, spaced 1m apart. Next, polyethylene closed-cell foam board is attached to the bottom of the side wall along with the waterproof geotextile, and holes are drilled at the locations of the expansion bolts. The same method was used to process the end bends; (9) Installation of crack-limiting reinforcing bars The waterproof layer is a thin layer of concrete about 10cm thick. To prevent cracking of this thin layer of concrete, a crack-limiting steel mesh is added. The diameter of the steel bars in the crack-limiting steel mesh is ø8-ø10mm, the spacing is about 20cm, and it is set on the surface layer of the newly added base slab concrete, with a protective layer of 1-2cm. (10) Concrete pouring Ready-mixed concrete is used, and the strength grade of the concrete can be the same as that of the original canal bottom slab concrete. After being transported to the construction site by concrete mixer trucks, the canal top road is used as the passage road for the mixer trucks, and the chute of the mixer trucks is lengthened to flow into the bottom of the canal. The top of the connection between the channel bottom slab and the side wall, and the connection between the bottom slab end and the original channel bottom slab, is separated by long strip templates. After the concrete has set, the templates are removed and filled with two-component polysulfide sealant. At the expansion joint of the original base slab in the newly waterproofed section, polyethylene closed-cell foam board + two-component polysulfide sealant is used as the expansion joint, running through the top and bottom.

[0016] The waterproofing construction method applicable to existing channels is described in step (4) using a mass ratio, where cement:sand:water:acrylic emulsion = 1:1.5:0.1:0.25-0.3.

[0017] The aforementioned method for adding waterproofing to existing channels involves step (9) firstly, the pad blocks are centrally and mechanically pressed in the factory, and steel mesh is centrally customized on-site according to the width of the channel and the length of the expansion joint. After prefabrication, the mesh is transported to the site. The pad blocks are then evenly placed on the waterproof geotextile, with small pieces of waterproof geotextile placed between the pad blocks and the waterproof geotextile to prevent damage to the main layer of waterproof geotextile after the pad blocks are compressed. Then, the steel mesh is placed on the pad blocks.

[0018] Compared with existing technologies, the beneficial effects of this invention are as follows: This construction method uses waterproof geotextile at the bottom of the channel and thin-layer concrete reinforced with crack-limiting steel bars as the main structure for waterproofing the bottom slab. The waterproof geotextile is mainly made of polyvinyl chloride (PVC) and polyethylene (PE), which is a high-molecular chemical flexible material with low specific gravity, high elongation, high adaptability to deformation, corrosion resistance, low temperature resistance, and good frost resistance. Its main mechanism is to use the impermeability of the plastic film to block leakage channels, and to withstand water pressure and adapt to deformation with its high tensile strength and elongation. Non-woven fabric is also a high-molecular short-fiber chemical material, which is formed by needle punching or thermal bonding and has high tensile strength and elongation. When combined with the plastic film, it not only increases the tensile strength and puncture resistance of the plastic film, but also increases the friction coefficient of the contact surface due to the rough surface of the non-woven fabric, which is beneficial to the stability of the composite geomembrane and protective layer. At the same time, they have good resistance to bacterial and chemical corrosion and are not afraid of acid, alkali, and salt corrosion. Sidewall waterproofing uses acrylic emulsion waterproof mortar, which can be applied to damp surfaces. Application can be done within the concrete mixing process. The impact of the object on the substrate increases the adhesion of the coating to the concrete. Simultaneously, the acrylic emulsion waterproofing and anti-corrosion material fills the pores and micro-cracks in the mortar, giving the coating excellent impermeability. Its adhesion strength is 3 to 4 times higher than ordinary cement mortar, and its flexural strength is more than 3 times higher, resulting in better crack resistance. It can be used for waterproofing, anti-corrosion, and moisture protection on water-facing and backwater surfaces, slopes, and irregular surfaces. It has strong adhesion and will not cause hollow areas, cracks, or water seepage. Acrylic emulsion waterproofing and anti-corrosion material can be used for waterproofing, anti-corrosion, leak sealing, and repair. No leveling or protective layer is required, and the project can be completed within one day. The construction period is short, and the overall cost is low. It can be applied to damp or dry substrates, but the substrate must not have running or standing water. Cationic chloroprene latex possesses the general properties of chloroprene rubber, exhibiting excellent mechanical properties. It is resistant to sunlight, ozone, atmospheric and seawater aging, and corrosion from oils, acids, alkalis, and other chemicals. It is heat-resistant, non-flammable, self-extinguishing, deformation-resistant, vibration-resistant, wear-resistant, has good airtightness and water resistance, and high overall adhesive strength. It is non-toxic and harmless, suitable for use in drinking water tank construction, and construction is safe and simple.

[0019] A special waterproofing system is constructed at the junction of the base slab and side walls, the junction of the waterproofed section of the base slab and the original base slab, and at expansion joints. The overall waterproofing effect is excellent, effectively preventing channel leakage and ensuring the stability of the embankment, as well as the stability of surrounding roads and buildings. Attached Figure Description

[0020] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0021] Figure 1 This is a flowchart of the construction process of this invention.

[0022] Figure 2 This is a schematic diagram of the removal of the channel bottom port according to the present invention.

[0023] Figure 3 This is a cross-sectional view of the waterproof geotextile laid according to the present invention.

[0024] Figure 4 This is a schematic diagram of the geotextile being folded and laid at the end of the invention.

[0025] Figure 5 This is a schematic diagram of the angle treatment of the present invention.

[0026] Figure 6 This is a schematic diagram of the connection between the channel bottom plate and the side wall of the present invention.

[0027] Figure 7 This is a cross-sectional view of the channel sidewall after being coated with acrylic emulsion waterproof mortar according to the present invention.

[0028] Figure 8 This is a cross-sectional view of the connection between the waterproof treatment part of the channel bottom plate and the original channel bottom plate of the present invention.

[0029] Figure 9 This is a cross-sectional view of the channel expansion joint location of the present invention.

[0030] Figure 10 This is a schematic diagram of the channel seepage prevention treatment range of the present invention.

[0031] Figure 11 This is a schematic diagram of the channel cross-section of the present invention.

[0032] Figure 12 This is a schematic diagram of the seam treatment of the present invention.

[0033] Figure 13 This is a schematic diagram of the treatment at the connection between the newly constructed concrete slab and the original channel bottom slab according to the present invention. Detailed Implementation

[0034] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of the present invention.

[0035] A waterproofing construction method applicable to existing channels is proposed. This method employs different base surface treatments for different parts of the existing channel and applies different waterproofing treatments based on the severity of seepage in different parts. The main steps include channel bottom treatment, mortar leveling, laying of waterproof geomembrane, corner treatment, installation of surface reinforcement, concrete pouring, and sidewall treatment. Specific steps include: First, contact the channel management department to cut off the water flow in the channel to be treated.

[0036] (1) Remove brush bristles from the side wall The existing canal walls, constantly soaked by rainwater, suffered extensive surface corrosion and damage, and were largely covered with moss and aquatic plants. The treatment involved first using a small hammer to break down the rotten mortar or concrete, then using a small shovel to remove the attached concrete along with the moss and aquatic plants. Finally, a mixture of salt, baking soda, dish soap, and water was sprayed onto the walls, which were then thoroughly scrubbed with a wire brush. The resulting waste material naturally flowed to the bottom of the canal and was treated along with the dredging.

[0037] (2) Dredging and flushing of the canal bottom Due to the constant erosion from water flow, the bottom of the channel is covered with slippery aquatic plants and a thin layer of silt. To avoid damaging the original channel floor, the silt layer is removed manually. An excavator bucket is lowered to the bottom of the channel, and workers use flat-headed shovels to shovel the silt into the excavator bucket, which is then loaded into dump trucks and transported to a treatment plant. Next, a small hammer is used to break up any hollow, warped, or rotten concrete at the bottom of the channel, and this debris is shoveled into the excavator bucket along with the silt. Finally, the entire channel, including the sidewalls and floor, is thoroughly washed using a high-pressure water jet.

[0038] (3) Remove the bottom end of the canal To ensure a smooth connection between the base plate of the newly waterproofed section of the channel and the existing channel, the joint of the section to be treated will be chiseled away, with the chiseling height being approximately 10cm, the same as the height of the new channel. First, a lime line will be marked at the end of the channel to be waterproofed. Then, an electric cutter will be used to cut along the lime line, followed by chiseling away the excess material using a pneumatic pick or electric hammer along the slope. Figure 2 As shown.

[0039] (4) Mixing of acrylic emulsion mortar The mix proportion is based on a mass ratio, where cement:sand:water:acrylic emulsion = 1:1.5:0.1:0.25-0.3. The minimum strength grade of the cement used shall not be lower than 42.5 MPa.

[0040] To prepare acrylic emulsion mortar, first dry mix the cement and sand evenly, then add the acrylic emulsion and mix evenly. Next, add water; if the consistency is not suitable, adjust the amount of cement and water as needed. The mortar should be able to form a ball when squeezed in your hand, without sticking to your hands or forming a water film. Wrap the mixed mortar in plastic wrap, and after pre-shrinking, knead it into a ball by hand for later use (ideally within 1 hour).

[0041] (5) Apply acrylic emulsion waterproof mortar: The side wall is filled with acrylic emulsion waterproof mortar. A layer of acrylic emulsion waterproof cement slurry (prepared by mass ratio of acrylic emulsion: cement = 1:2) is evenly applied to the cleaned base surface. After about 15 minutes, acrylic emulsion waterproof mortar is applied to form acrylic emulsion waterproof cement slurry layer 9. The acrylic emulsion waterproof mortar layer 9 is compacted and smoothed. It is covered after 2 hours and watered for curing after 8 hours. (6) Cement mortar leveling of the bottom slab of the water channel Use cement mortar with the same mix ratio as the bottom slab of the canal to fill and level any uneven areas on the bottom slab of the canal, and then smooth the surface. (7) Waterproof geotextile laying The waterproof geotextile should be laid on the bottom slab of the channel, and folded in half at the corner where the bottom slab meets the sidewall to prevent cracking. The laying cross-section is as follows: Figure 3 As shown: The waterproof geotextile is laid using a width customized to the channel bottom plus the width after folding both sides. It is laid along the entire width of the channel. Construction workers must wear cloth shoes or soft rubber shoes for laying; walking on the waterproof geotextile with spiked shoes or high heels is strictly prohibited. Laying begins from one end of the channel to be treated and proceeds to the other, with the geotextile folded in half at the ends. Figure 4 As shown; During the laying of waterproof geotextile, the contact points of different waterproof geotextiles are overlapped and sewn together. The waterproof geotextile downstream of the channel water flow direction is placed below the upstream geotextile and overlapped and welded using qualified special welding equipment. (8) Corner treatment There are two types of angle bends in this construction method: one is the angle between the channel bottom plate and the side wall, and the other is the angle between the channel end and the original channel.

[0042] First, a Q235 steel plate 4, approximately 3mm thick and 3cm wide, is attached to the sidewall. This position is close to the fold of the waterproof geotextile 1 but does not overlap with it. Expansion bolts 3 are used to fix the steel plate to the sidewall, with each bolt spaced approximately 1m apart. Then, a polyethylene closed-cell foam board 5 (approximately 2cm narrower than the newly added waterproof bottom slab) is attached to the bottom of the sidewall along with the waterproof geotextile 1. Holes are drilled at the locations of the expansion bolts 3. The cross-section is as follows. Figure 5 As shown; The same method is used to process the end bends, such as... Figure 8 As shown; (9) Installation of crack-limiting reinforcing bars This method involves adding a thin concrete waterproof layer, approximately 10cm thick. To prevent cracking of this thin concrete layer, a crack-limiting steel mesh 7 is added. The diameter of the steel bars in the crack-limiting steel mesh 7 is ø8-ø10mm, with a spacing of approximately 20cm. It is installed on the surface layer of the newly added base slab concrete, with a protective layer of 1-2cm. Specifically, the crack-limiting steel mesh 7 is installed inside the base slab concrete layer 8, and a two-component polysulfide sealant 6 is applied between the polyethylene closed-cell foam board 5 and the base slab concrete layer 8. First, the spacer blocks (not shown in the diagram) are centrally and mechanically pressed in the factory. Then, steel mesh is prefabricated on-site according to the channel width and expansion joint length, and transported to the site. The spacer blocks are then evenly placed on the waterproof geotextile, with small pieces of waterproof geotextile placed between the blocks and the geotextile to prevent damage to the main waterproof geotextile layer under pressure. Next, the steel mesh is placed on the spacer blocks. This completes the steel mesh installation.

[0043] (10) Concrete pouring Ready-mixed concrete is used, and the strength grade of the concrete can be the same as that of the original canal bottom slab concrete. After being transported to the construction site by concrete mixer trucks, the canal top road is used as the passageway for the mixer trucks, and the chute of the mixer trucks is lengthened to flow into the bottom of the canal.

[0044] The top of the connection between the channel bottom slab and the side wall, and the connection between the bottom slab end and the original channel bottom slab, is separated by long strip templates. After the concrete has set, the templates are removed and filled with two-component polysulfide sealant. At the connection between the channel bottom plate and the side wall, such as Figure 6 As shown; Waterproofing treatment at the connection between the channel end and the original channel bottom plate, such as... Figure 8 As shown; At the expansion joints of the original base slab in the newly waterproofed section, polyethylene closed-cell foam board + two-component polysulfide sealant is used as the expansion joint, running vertically through the entire structure; For example... Figure 9 As shown.

[0045] This invention was applied to the Guangxi Baise Reservoir Irrigation Area Section II project, where water leakage at the bottom of the Ertang branch canal caused water to overflow from the toilets of nearby residents. The above-mentioned construction method was used to treat the canal.

[0046] (1) Surface treatment 1) Crack-limiting steel bars φ8@200x200 are installed on the surface layer.

[0047] 2) Lay an impermeable geomembrane on the original channel bottom slab and the outer concrete surface.

[0048] 3) After removing the original mortar plaster, apply a 20mm thick layer of acrylic emulsion waterproof mortar. (If it is a concrete surface, simply roughen it before applying a 20mm thick layer of acrylic emulsion mortar.)

[0049] 4) After removing / roughening the surface of the original channel sidewall, apply a 20mm thick layer of acrylic emulsion waterproof mortar.

[0050] 5) Construct a new C20(1) concrete slab with a thickness of 100mm.

[0051] (2) Treatment of joints A geomembrane was laid between the existing channel bottom slab and the newly built C20(1) concrete bottom slab. The joints of the original channel bottom slab were sealed with two-component polysulfide sealant and polyethylene closed-cell foam board.

[0052] (3) Treatment of the joint between the new concrete slab and the original channel bottom slab At the starting and ending points of the new foundation slab, the original channel foundation slab needs to be partially removed. A geomembrane (specifications: 100g / 0.5 / 100g) should be installed. Two-component polysulfide sealant and polyethylene closed-cell foam board should be used at the joint between the new concrete slab and the original channel foundation slab. When there are bolt fixing points, the foam board should be opened and expansion bolts should be installed with a hole spacing of 1m. A 30mm wide Q235 steel plate with a thickness of 3mm should be added, and the geomembrane should be folded in half to prevent cracking. The fold should be 50mm.

[0053] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for installing waterproofing on existing channels, characterized in that, The steps include: (1) Remove brush bristles from the side wall Mix salt, baking soda, dish soap and water, spray the mixture onto the side wall and scrub it thoroughly with a wire brush; (2) Dredging and flushing of the canal bottom The excavator bucket is lowered to the bottom of the canal, and the silt at the bottom of the canal is shoveled into the excavator bucket by hand using a flat-headed shovel. It is then loaded into a dump truck and transported to the treatment plant for processing. Next, a small hammer is used to hammer the hollow, warped, and rotten concrete at the bottom of the canal, and it is shoveled into the excavator bucket along with the silt. Finally, the side walls and bottom plate are washed together with a high-pressure water gun. (3) Remove the bottom end of the canal To ensure a smooth connection between the bottom plate of the newly waterproofed section of the channel and the existing channel, the joint of the section to be treated is chiseled away, with the chiseling height being approximately 10cm, the same as the height of the new channel. First, a lime line is sprinkled at the end of the channel to be waterproofed, then an electric cutter is used to cut along the lime line, and then a pneumatic pick or electric hammer is used to chisel away the section along the slope. (4) Mixing of acrylic emulsion mortar To prepare acrylic emulsion mortar, first dry mix the cement and sand evenly, then add the acrylic emulsion and mix evenly, then add water. Wrap the mixed mortar with plastic sheeting, and after pre-shrinking, take a ball by hand and knead it for later use. (5) Apply acrylic emulsion waterproof mortar: For filling the side wall with acrylic emulsion waterproof mortar, apply a layer of acrylic emulsion waterproof cement slurry evenly on the pre-washed base surface, and start applying acrylic emulsion waterproof mortar 15 minutes later. Compact and smooth the acrylic emulsion waterproof mortar layer, cover it after 2 hours, and carry out water curing after 8 hours. (6) Cement mortar leveling of the bottom slab of the water channel Use cement mortar with the same mix ratio as the bottom slab of the canal to fill and level any uneven areas on the bottom slab of the canal, and then smooth the surface. (7) Waterproof geotextile laying The waterproof geotextile is laid on the bottom slab of the channel and is folded in half at the corner where the bottom slab meets the side wall to prevent cracking. The waterproof geotextile is made by adding the width of the channel bottom to the width of the fabric after folding it in half on both sides. When laying it, it is laid in full along the width of the channel, from one end of the channel to be treated to the other end, and the geotextile is folded in half at the end. During the laying of waterproof geotextile, the contact points of different waterproof geotextiles are overlapped and sewn together. The waterproof geotextile downstream of the channel water flow direction is placed below the upstream geotextile and overlapped and welded using qualified special welding equipment. (8) Corner treatment First, a steel plate is attached to the side wall, close to the fold of the waterproof geotextile but not overlapping it. The steel plate is then fixed to the side wall with expansion bolts, spaced 1m apart. Next, polyethylene closed-cell foam board is attached to the bottom of the side wall along with the waterproof geotextile, and holes are drilled at the locations of the expansion bolts. The same method was used to process the end bends; (9) Installation of crack-limiting reinforcing bars The waterproof layer is a thin layer of concrete about 10cm thick. To prevent cracking of this thin layer of concrete, a crack-limiting steel mesh is added. The diameter of the steel bars in the crack-limiting steel mesh is ø8-ø10mm, the spacing is about 20cm, and it is set on the surface layer of the newly added base slab concrete, with a protective layer of 1-2cm. (10) Concrete pouring Ready-mixed concrete is used, and the strength grade of the concrete can be the same as that of the original canal bottom slab concrete. After being transported to the construction site by concrete mixer trucks, the canal top road is used as the passage road for the mixer trucks, and the chute of the mixer trucks is lengthened to flow into the bottom of the canal. The top of the connection between the channel bottom slab and the side wall, and the connection between the bottom slab end and the original channel bottom slab, is separated by long strip templates. After the concrete has set, the templates are removed and filled with two-component polysulfide sealant. At the expansion joint of the original base slab in the newly waterproofed section, polyethylene closed-cell foam board + two-component polysulfide sealant is used as the expansion joint, running through the top and bottom.

2. The waterproofing construction method for existing channels according to claim 1, characterized in that, In step (4), the mix proportion is based on the mass ratio, where cement:sand:water:acrylic emulsion = 1:1.5:0.1:0.25-0.

3.

3. The waterproofing construction method for existing channels according to claim 1, characterized in that, In step (9), the pad blocks are first pressed by centralized machinery in the factory, and steel mesh is customized in the field according to the width of the channel and the length of the expansion joint. After the prefabrication is completed, it is transported to the site. The pad blocks are first evenly placed on the waterproof geotextile, and small pieces of waterproof geotextile are placed between the pad blocks and the waterproof geotextile to prevent the main layer of waterproof geotextile from being damaged after the pad blocks are pressed. Then the steel mesh is placed on the pad blocks.

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