High flow rate water release channel self-suction drainage device and construction method

Abstract

The application discloses a high-flow-speed water discharge channel self-suction type drainage device and a construction method, and relates to the field of drainage devices.The drainage device comprises a plurality of drainage mechanisms and a plurality of guide pier fins.The drainage mechanisms are arranged on the outside of the water discharge channel and are connected to the drainage holes of the water discharge channel.The guide pier fins are arranged on the inside of the water discharge channel and are arranged on the upstream water side of the drainage holes.The water discharge channel is arranged in the underground rock mass, and the air supplement pipe is embedded in the water discharge channel.The construction method comprises the following steps: S1, measuring and laying out;S2, drilling construction;S3, drainage pipe production and installation;S4, anti-filter material layering filling;S5, water-permeable cover plate installation;S6, steel anchor rod installation;S7, guide pier fin pouring;S8, air supplement pipe pre-embedding and communication;S9, surface finishing and inspection.The guide pier fins are arranged on the upstream water side of the drainage holes, the open drainage holes can be arranged on the surface of the high-speed water flow channel, and the key technical problem that the open drainage holes cannot be arranged on the surface of the high-flow-speed water discharge channel is solved.

Description

Technical Field

[0001] This invention belongs to the technical field of underground drainage tunnel structure design in hydropower projects, specifically relating to a high-velocity drainage channel self-priming drainage device and construction method. Background Technology

[0002] During the construction of hydropower stations, due to the need for the layout of the hub, spillway channels are often arranged on the mountainside. Due to geological conditions and the design requirements of the structure itself, the spillway channels have large cross-sectional dimensions, high flow velocities, and are buried deep underground. The structure bears a high external water head, which brings great challenges to the design of the channel structure. As a result, the channel structure is large in size, has a thick lining, and the structural reinforcement exceeds the existing design specifications.

[0003] Currently, drainage channels for high-speed water flow can only have drainage holes installed above the water surface. Below the water surface, due to the influence of high-speed water flow, open drainage holes cannot be installed. If open drainage holes cannot be installed in large-aperture drainage channels, the external water head borne by the structure will be high, resulting in excessive structural dimensions and reinforcement.

[0004] If underground drainage galleries are constructed around the drainage channel, the cross-sectional dimensions of these galleries are typically large to meet construction requirements, with a minimum cross-sectional dimension of 2 meters. This significantly increases project investment, and the drilling of drainage holes within the galleries is subject to limitations, making it difficult to guarantee construction quality. Drainage galleries are generally not feasible when the channel structure is complex and the slope is steep.

[0005] In the prior art, Chinese patent No. 2026102811418 discloses a device and construction method for draining external water from a high-velocity, large-section, deeply buried, unpressurized drainage tunnel. The device has a relatively complex structure and is difficult to maintain. Chinese patent No. CN204327188 U discloses an underground tunnel drainage mechanism. This structure is difficult to drain external water below the water surface and has a shallow drainage depth. Chinese patent No. CN 202544925 U discloses a tunnel drainage hole structure with one hole serving two purposes. This structure is difficult to drain external water from a high-velocity, unpressurized drainage tunnel and has weak drainage capacity. Summary of the Invention

[0006] The purpose of this invention is to address the deficiencies and shortcomings in the prior art by providing a high-flow-rate self-priming drainage device and its construction method.

[0007] The technical solution of this invention: A high-velocity self-priming drainage device for a drainage channel includes several drainage mechanisms and several guide fins. The drainage mechanisms are arranged on the outside of the drainage channel and connected to the drainage holes of the drainage channel. The guide fins are arranged on the inside of the drainage channel and are located on the upstream side of the drainage hole. The drainage channel is opened in the underground rock mass, and an air supply pipe is pre-embedded inside the drainage channel.

[0008] The drainage mechanism includes a drainage pipe and a non-woven geotextile. Several drainage filter holes are opened on the side wall of the drainage pipe. The inside of the drainage pipe is filled with a sponge layer, a fine sand layer and a gravel layer from the inlet end to the outlet end. A permeable cap is installed on the side of the sponge layer away from the fine sand layer. The non-woven geotextile is wrapped around the outside of the drainage pipe.

[0009] The permeable cap plate is provided with several permeable holes and is equipped with protruding studs for fastening or disassembling the permeable cap plate. The opening rate of the permeable holes on the permeable cap plate is not less than 15%, and the diameter of the permeable holes is 3mm±0.2mm.

[0010] The guide fin includes a head cone and a tail blade. The head cone is fixedly installed on the side wall of the drainage channel by steel anchor rods, and the tail blade is connected to the tail end of the head cone.

[0011] The height and width of the guide fin are 1.5 ± 0.2 times the diameter of the drainage hole, the body shape is conical and streamlined, and the length of the tail blade is 2.0 ± 0.2 times the diameter of the drainage hole.

[0012] A construction method for arranging a self-priming drainage device for a high-velocity drainage channel includes the following steps: S1: Surveying and setting out, pouring out the drainage channel with lining concrete, and after completion and reaching the design strength, setting out and marking the installation positions of the drainage holes and guide fins; S2: Drilling construction. After the lining concrete reaches more than 90% of the design strength, drill drainage holes. During the drilling process, use clean water to flush the holes and remove slag, rock powder and concrete debris from the holes. After the holes are formed, conduct through-hole inspection. S3: Drainage pipe fabrication and installation. The length of the drainage pipe is configured according to the actual depth of the drainage hole on site, with a 20mm to 30mm exposed length reserved. The pipe wall is covered with several drainage filter holes in a quincunx pattern. The outside of the drainage pipe is wrapped with a layer of non-woven geotextile and tied and fixed. Then the entire drainage pipe is inserted into the drainage hole. After insertion, the exposed length is checked. S4: Layered filling of filter material. According to the "reverse filtration principle", the drainage pipe is filled with a sponge layer, a fine sand layer and a gravel layer from the inside to the outside. Each layer is lightly compacted after filling. S5: Installation of permeable caps: After the filter media is filled in layers, permeable caps are installed at the drainage hole openings. S6: Rebar anchor installation: Drill anchor holes using an impact drill at a location 300mm to 500mm upstream of the drainage hole on the water inlet side, insert rebar anchors, anchor them using high-strength structural anchoring adhesive, and then cure them. S7: The guide pier fin is cast in the field using C40 high-performance concrete with on-site formwork. The semi-cone angle of the guide pier fin is 30° to 45°. After the cast body of the guide pier fin is connected to the steel anchor rod, it is covered and watered for curing. S8: Pre-embedding and connecting the air supply pipe. Pre-embedding a PVC air supply pipe at the corresponding position of the negative pressure zone at the tail of the guide pier fin, so that one end of the PVC air supply pipe is connected to the negative pressure zone at the tail, and the other end is led to the atmospheric side outside the drainage channel. S9: Surface finishing and inspection. After the construction of drainage holes and guide fins is completed, the flow surface of the drainage channel is ground and finished. After the construction is completed, a water injection test is used to test the water permeability of the drainage holes, and a micro-manometer is used to measure the negative pressure value of the tail negative pressure zone on site. After the inspection is qualified, the process can proceed to the next step.

[0013] In step S1, a total station is used for layout and positioning. The layout deviation of the drainage hole position is ±20mm, and the deviation of the distance between adjacent drainage holes is ±30mm.

[0014] In step S2, the diameter of the drainage hole is 55mm to 60mm, the depth of the drainage hole penetrates the lining structure of the drainage channel and enters the surrounding rock 50mm to 100mm, and the deviation of the direction of the drainage hole from the normal direction of the flow surface of the drainage channel is ±3°.

[0015] In step S3, the drainage filter hole diameter is 10mm±1mm, the hole spacing is 50cm±2cm, and the staggered arrangement angle is 60°±2°; the surface density of the non-woven geotextile is 100g / ㎡~150g / ㎡, and the circumferential overlap width is not less than 100mm; nylon cable ties are used for binding and fixing, and the spacing of the nylon cable ties is 200mm±5mm.

[0016] In step S4, the sponge layer is made of polyurethane sponge with a density of 25-30 kg / m³. 3 The filling thickness is 20%±2% of the drainage hole depth; the fine sand layer has a fine sand particle size of 0.5mm~2mm and a filling thickness of 30%±2% of the drainage hole depth; the crushed stone layer has a crushed stone particle size of 5mm~10mm and a filling thickness of 40%±2% of the drainage hole depth.

[0017] In step S5, the permeable cap plate with internal threads is tightened using a torque wrench with a torque of 15 N·m to 20 N·m.

[0018] In step S6, the diameter of the anchor hole is 22mm±1mm and the depth is 150mm±2mm; the diameter of the steel anchor rod is 20mm±1mm and the length is 200mm±2mm, and the exposed length of the steel anchor rod is 80mm~100mm; the curing temperature is 20℃ and the curing time is not less than 24 hours; the spacing between two adjacent steel anchor rods along the width of the drainage channel is 1.5±0.1 times the diameter of the drainage hole.

[0019] In step S7, the tail blade of the guide pier fin is made of high-performance concrete or stainless steel with a thickness of 8mm to 10mm; it is covered and watered for curing for no less than 7 days, with watering no less than 3 times a day; when stainless steel precast parts are used, they are fully welded to the steel anchor rods, with a weld height of no less than 6mm, and weld flaw detection is performed after welding.

[0020] In step S8, temporary sealing measures are taken to prevent debris from blocking the pre-embedded PVC gas supply pipe. After installation, the sealing debris is removed and the pipeline is checked for unobstructed flow.

[0021] In step S9, during the grinding and finishing process, the surface flatness error is controlled to be ±5mm / 2m, and the permeability performance of the drainage hole is tested. The single hole drainage flow rate is required to be not less than 0.5L / min, and the negative pressure value is required to be not less than -2kPa.

[0022] The beneficial effects of this invention are: This invention solves the key technical problem of not being able to install open drainage holes on the surface of high-velocity water flow channels by arranging water flow guide fins on the upstream side of the drainage hole. Simultaneously, the drainage hole is filled with materials such as gravel, fine sand, and sponge according to the reverse filtration principle, solving the problem of easy clogging. The drainage hole opening is secured with a permeable cap plate via internal threads, which is removable and allows for later replacement of the reverse filtration material inside the hole, ensuring convenient and reliable operation.

[0023] After the high-speed water flow passes through the guide fin, a negative pressure zone can be formed at the tail. The negative pressure generated can exert suction on the seepage water in the drainage hole, accelerate the discharge of water from outside the mountain outside the drainage channel, and effectively protect the safety of the drainage channel lining structure.

[0024] This device can install open drainage holes on the surface of the high-velocity drainage channel lining structure and ensure reliable operation of the structure, preventing cavitation erosion damage to the channel surface caused by the installation of drainage holes.

[0025] This device effectively reduces the external water head outside the tunnel lining, significantly reducing the external water pressure on the structure and achieving zero external pressure capability. This allows the tunnel structure to be free from external water pressure, and only the structural requirements need to be met for the tunnel lining structure and reinforcement, while also satisfying the specifications.

[0026] This device achieves the effect of reducing external water discharge below the water surface line in high-speed water flow. In particular, when the water flow is high-speed, an open drainage hole can be set below the water surface line, which effectively solves the problem that the open drainage hole will be severely damaged by cavitation and cavitation due to the influence of high-speed water flow, and ensures that the flow channel will not be damaged by cavitation and cavitation.

[0027] The open drainage system of this application is easy to construct, install and manufacture, and has strong applicability. It significantly reduces the thickness of the structural lining and the amount of reinforcement. Engineering application practice has proven that the lining structure of high flow velocity drainage channels can be configured with only a single layer of structural steel reinforcement. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the cross-sectional structure of the drainage device of the present invention; Figure 2 This is a three-dimensional layout diagram of the drainage device of the present invention; Figure 3 This is a cross-sectional view of the drainage mechanism in this invention; Figure 4 This is a schematic diagram of the connection structure between the permeable cap plate and the drainage pipe of the present invention; Figure 5 This is a three-dimensional structural diagram of the flow guide fins of the present invention; Figure 6 This is a schematic diagram of the planar arrangement of the guide fins of the present invention.

[0029] Reference numerals: 1-Drainage mechanism, 2-Guide fin, 3-Drainage channel, 4-Water surface line, 5-Excavation outline, 6-Underground rock mass, 11-Permeable cap, 12-Sponge layer, 13-Fine sand layer, 14-Gravel layer, 15-Drainage pipe, 16-Drainage filter hole, 17-Non-woven geotextile, 21-Head cone, 22-Tail blade, 23-Reinforcing bar anchor, 24-Tail negative pressure zone, 25-High-speed water flow, 26-Flow surface, 111-Protruding stud, 112-Permeable hole. Detailed Implementation

[0030] refer to Figures 1-6 A high-velocity self-priming drainage device for a drainage channel includes several drainage mechanisms 1 and several guide fins 2. The drainage mechanisms 1 are arranged on the outside of the drainage channel 3 and connected to the drainage hole of the drainage channel 3. The guide fins 2 are arranged on the inside of the drainage channel 3 and are located on the upstream side of the drainage hole. The drainage channel 3 is opened in the underground rock mass 6, and an air supply pipe is pre-embedded inside the drainage channel 3.

[0031] In this application, the pre-embedded air supply pipe is pre-embedded during the pouring of the lining structure of the drainage channel 3; drainage holes are drilled on the surface of the lining structure of the drainage channel 3.

[0032] The device described in this application is mainly applicable to the arrangement of the excavation outline 5 of the drainage channel 3.

[0033] The drainage mechanism 1 includes a drainage pipe 15 and a non-woven geotextile 17. Several drainage filter holes 16 are opened on the side wall of the drainage pipe 15. The inside of the drainage pipe 15 is filled with a sponge layer 12, a fine sand layer 13 and a gravel layer 14 from the inlet end to the outlet end. A permeable cap plate 11 is installed on the side of the sponge layer 12 away from the fine sand layer 13. The non-woven geotextile 17 is wrapped around the outside of the drainage pipe 15.

[0034] The permeable cap plate 11 is provided with a plurality of permeable holes 112 and is equipped with protruding studs 111 for fastening or disassembling the permeable cap plate 11. The opening rate of the permeable holes 112 on the permeable cap plate 11 is not less than 15%, and the diameter of the permeable holes 112 is 3mm±0.2mm.

[0035] In this application, a drainage pipe 15 is installed in the drainage hole. The drainage pipe 15 is filled with gravel 14, fine sand 13 and sponge 12 in sequence from the outside to the inside according to the reverse filtration principle. Then, the first permeable cap plate 11 is installed at the opening of the drainage hole.

[0036] Specifically, the drainage hole filling material is filled from the outside to the inside according to the "reverse filtration principle". After filling, the drainage hole is sealed with a permeable cap plate 11.

[0037] The guide fin 2 includes a head cone 21 and a tail blade 22. The head cone 21 is fixedly installed on the side wall of the drainage channel 3 by a steel anchor 23, and the tail blade 22 is connected to the tail end of the head cone 21.

[0038] Steel anchor rods 23 are installed on the surface of the flow channel in the direction of water in the upstream side of the drainage hole. Guide fins 2 are welded on the steel anchor rods 23 to complete the cavitation protection of the drainage hole.

[0039] In this application, the high-speed water flow 25 is guided by the guide fin 2 to pass over the drainage hole opening, effectively protecting the drainage hole opening and preventing cavitation damage at the opening. Simultaneously, the tail of the guide fin 2, led by the high-speed water flow 25, forms a negative pressure zone 24, draining the seepage water from the mountain within the drainage hole. The air supply pipe at the tail of the guide fin 2 can replenish air to the negative pressure zone, further protecting the drainage hole opening from cavitation damage.

[0040] In this application, the drainage holes need to be drilled after the concrete lining of the drainage channel 3 is poured, and mechanical equipment is used for drilling.

[0041] The drainage pipe 15 inside the drainage hole is made of corrosion-resistant material, usually stainless steel. The hole diameter is the nominal diameter, preferably 5cm. Holes with a diameter of 1cm are drilled on the wall of the drainage pipe 15, with a hole spacing of 50cm, arranged in a quincunx pattern. The drainage pipe 15 is wrapped with non-woven geotextile 17.

[0042] The height and width of the guide fin 2 are 1.5 ± 0.2 times the diameter of the drainage hole, and the body shape is conical and streamlined. The length of the tail blade 22 is 2.0 ± 0.2 times the diameter of the drainage hole.

[0043] Specifically, the guide fin 2 is installed on the upstream side of the drainage hole opening, and is installed on the surface of the flow channel using steel anchor rods 23. The height and width of the guide fin 2 should be 1.5 times the diameter of the drainage hole, and the body shape is a conical streamline shape. The length of the tail blade 22 is 2.0 times the diameter of the drainage hole, and the material is high-performance concrete or stainless steel.

[0044] Drainage holes should be installed on the sidewalls and bottom slabs of the flow channel, with two holes installed on each sidewall and bottom slab. Additional holes can be installed based on the actual external water head of the project to meet drainage requirements.

[0045] A construction method for arranging a self-priming drainage device for a high-velocity drainage channel includes the following steps: S1: Measure and lay out the lines. Pour out the drainage channel 3 with lining concrete. After the channel is completed and reaches the design strength, lay out and mark the installation positions of the drainage holes and the guide fins 2. A total station was used for layout and positioning. The layout deviation of the drainage hole position was ±20mm, and the deviation of the distance between adjacent drainage holes was ±30mm.

[0046] In this application, after the concrete lining of the drainage channel 3 is poured and reaches the design strength, a total station is used to lay out and locate the installation positions of the drainage holes and the guide fin 2. The allowable deviation of the drainage hole position is controlled within ±20mm, and the allowable deviation of the distance between adjacent drainage holes is ±30mm. The layout points are marked with red paint.

[0047] S2: Drilling construction. After the lining concrete reaches more than 90% of the design strength, drill drainage holes. During the drilling process, use clean water to flush the holes and remove slag, rock powder and concrete debris from the holes. After the holes are formed, conduct through-hole inspection. The diameter of the drainage hole is 55mm to 60mm, and the depth of the drainage hole penetrates the lining structure of the drainage channel 3 and enters the surrounding rock 50mm to 100mm. The deviation of the direction of the drainage hole from the normal direction of the flow surface 26 of the drainage channel 3 is ±3°.

[0048] The specific steps are as follows: After the lining concrete reaches more than 90% of its design strength (curing period under the same conditions is not less than 14 days), use a handheld hydraulic drill to drill the drainage holes. The hole diameter should be 55-60mm (5-10mm larger than the outer diameter of the drainage pipe 15). The drilling depth should penetrate the thickness of the lining structure and enter the surrounding rock 50-100mm. The drilling direction should be consistent with the normal direction of the flow channel surface, and the allowable deviation angle is ±3°. During the drilling process, use clean water to flush the hole and remove slag, and promptly remove rock powder and concrete debris from the drainage holes. After the hole is formed, conduct a through-hole inspection.

[0049] S3: Drainage pipe fabrication and installation. The length of drainage pipe 15 is configured according to the actual depth of the drainage hole on site, with a 20mm to 30mm exposed length reserved. The pipe wall is covered with several drainage filter holes 16 in a quincunx pattern. The outside of the drainage pipe is wrapped with a layer of non-woven geotextile and tied and fixed. Then, the entire drainage pipe 15 is inserted into the drainage hole. After insertion, the exposed length is checked. The drainage filter holes 16 have a diameter of 10mm±1mm, a hole spacing of 50cm±2cm, and an interleaved arrangement angle of 60°±2°; the non-woven geotextile 17 has a surface density of 100g / ㎡~150g / ㎡, and a circumferential overlap width of not less than 100mm; nylon cable ties are used for binding and fixing, and the spacing of the nylon cable ties is 200mm±5mm.

[0050] Drainage pipe 15 is made of 304 stainless steel with an outer diameter of 50mm and a wall thickness of 2mm. The length of drainage pipe 15 is configured according to the actual measured hole depth on site, with a 20-30mm exposed length reserved. The wall of drainage pipe 15 is covered with permeable holes 112 in a quincunx pattern, with a hole diameter of 10mm, a hole spacing of 50cm, and an alternating angle of 60°. The outside of drainage pipe 15 is wrapped with a layer of non-woven geotextile 17 with a surface density of 100-150g / ㎡, with a circumferential overlap width of not less than 100mm, and is fixed with nylon cable ties with a cable tie spacing of 200mm. The completed drainage pipe 15 is inserted into the drilled hole as a whole, and the exposed length is checked after insertion.

[0051] S4: The filter material is filled in layers. According to the "reverse filtration principle", the drainage pipe 15 is filled in layers from the inside to the outside, including sponge layer 12, fine sand layer 13 and gravel layer 14. Each layer is lightly compacted after filling. Sponge layer 12 is made of polyurethane foam with a density of 25-30 kg / m³. 3 The filling thickness accounts for 20% ± 2% of the drainage hole depth; the fine sand layer 13 has a fine sand particle size of 0.5 mm to 2 mm and a filling thickness of 30% ± 2% of the drainage hole depth; the crushed stone layer has a crushed stone particle size of 5 mm to 10 mm and a filling thickness of 40% ± 2% of the drainage hole depth.

[0052] In this step, the specific operation is as follows: according to the "reverse filtration principle," the reverse filtration material is filled in layers from the outside to the inside—a crushed stone layer 14 (particle size 5-10mm, filling thickness approximately 40% of the drainage hole depth), a fine sand layer 13 (particle size 0.5-2mm, filling thickness approximately 30% of the drainage hole depth), and a soft sponge layer 12 (polyurethane sponge, density 25-30kg / m³). 3 The filling thickness is about 20% of the depth of the drainage holes; after each layer is filled, it is lightly tamped with a 10mm diameter steel rod, and the tamping interval is no more than 100mm to avoid excessive vibration that would cause the filter layer to become disordered and lose its filter effect.

[0053] S5: Installation of permeable cap plate: After the filter material is filled in layers, install permeable cap plate 11 at the drainage hole opening; The permeable cap plate 11 has internal threads and is tightened with a torque wrench with a torque of 15 N·m to 20 N·m.

[0054] In this step, the specific operation is as follows: After the filter material is filled, a permeable cap plate 11 with internal threads is installed at the drain hole opening. The permeable cap plate 11 is made of 304 stainless steel or engineering plastic, and the diameter of the permeable holes on the plate is 3mm with an opening rate of not less than 15%. Tighten it with a torque wrench, and control the installation torque at 15~20N·m to ensure that the drain hole opening is reliably sealed and facilitates the later disassembly, maintenance and replacement of the filter material.

[0055] S6: Rebar anchor installation: 300mm to 500mm upstream of the drainage hole on the water inlet side, use an impact drill to drill anchor holes, insert rebar anchors 23, use high-strength structural anchoring adhesive for anchoring, and then cure. The anchor hole diameter is 22mm±1mm and the hole depth is 150mm±2mm; the steel anchor rod 23 has a diameter of 20mm±1mm and a length of 200mm±2mm, and the exposed length of the steel anchor rod 23 is 80mm~100mm; the curing temperature is 20℃ and the curing time is not less than 24 hours; the spacing between two adjacent steel anchor rods 23 along the width direction of the drainage channel 3 is 1.5±0.1 times the diameter of the drainage hole.

[0056] The specific operation in this step is as follows: 300-500mm upstream of the drainage hole on the water inlet side, an anchoring hole is drilled using an impact drill with a diameter of 22mm and a depth of 150mm; a steel anchor rod with a diameter of 20mm and a length of 200mm is inserted and anchored using high-strength structural anchoring adhesive, with a curing time of no less than 24 hours at an ambient temperature of 20℃; the exposed length of the steel anchor rod is controlled to be 80-100mm, and the spacing between two anchor rods along the width of the flow channel should be 1.5 times the diameter of the drainage hole.

[0057] S7: The guide pier fin is cast in the field using C40 high-performance concrete with on-site formwork. The head cone 21 of the guide pier fin has a semi-cone angle of 30° to 45°. After the cast body of the guide pier fin 2 is connected to the steel anchor 23, it is covered and watered for curing. The tail blade of the guide pier fin 2 is made of high-performance concrete or stainless steel with a thickness of 8mm to 10mm; it is covered and watered for curing for no less than 7 days, and watered no less than 3 times a day; when stainless steel precast parts are used, they are fully welded to the steel anchor rod 23, with a weld height of no less than 6mm, and weld flaw detection is performed after welding.

[0058] In this step, the specific operations are as follows: the guide pier fin 2 is constructed on-site using C40 high-performance concrete formwork, or on-site welding and installation using precast stainless steel components. During concrete pouring, the semi-cone angle of the head cone 21 is controlled between 30° and 45°, and the total height and width should be 1.5 times the diameter of the drainage hole. The length of the tail blade 22 is 2.0 times the diameter of the drainage hole, and the thickness is 8-10 mm. After the poured body is connected to the steel anchor rod 23, it is covered and watered for curing for no less than 7 days, with watering no less than 3 times a day. When using precast stainless steel components, they are fully welded to the steel anchor rod 23, with a weld height of no less than 6 mm. Weld flaw detection is performed after welding.

[0059] S8: Pre-embedding and connecting the air supply pipe. Pre-embedding a PVC air supply pipe at the corresponding position of the negative pressure zone 24 at the tail of the guide pier fin, so that one end of the PVC air supply pipe is connected to the negative pressure zone 24 at the tail, and the other end is led to the external atmospheric side of the drainage channel 3. Pre-embedded and connected air supply pipe: Pre-embed PVC air supply pipe at the corresponding position of the negative pressure zone 24 at the tail of the guide pier fin, so that one end of the PVC air supply pipe is connected to the negative pressure zone 24 at the tail, and the other end is led to the external atmosphere side of the drainage channel 3. In this step, the specific operation is as follows: a PVC air supply pipe with a diameter of 25mm is pre-buried at the corresponding position of the negative pressure zone 24 at the tail of the guide fin 2. One end is connected to the negative pressure zone 24 at the tail, and the other end is led to the external atmospheric side of the drainage channel 3. During the pre-burying stage, temporary sealing measures are taken to prevent debris from blocking the pipe. After the installation is completed, the sealing is removed and the pipeline is checked for unobstructed flow.

[0060] S9: Surface finishing and inspection. After the construction of drainage holes and guide fins is completed, the flow surface 26 of the drainage channel 3 is ground and finished. After the construction is completed, a water injection test is used to test the water permeability of the drainage holes, and a micro pressure gauge is used to measure the negative pressure value of the tail negative pressure zone 24 on site. After the inspection is qualified, the next process can be carried out.

[0061] During the grinding and finishing process, the surface flatness error is controlled to be ±5mm / 2m. The permeability of the drainage holes is tested, requiring a single hole drainage flow rate of not less than 0.5L / min and a negative pressure value of not less than -2kPa.

[0062] In this step, the specific operations are as follows: After the construction of the drainage hole and the guide fin 2 is completed, the flow surface 26 is ground and repaired to control the surface flatness error to ±5mm / 2m, so as to avoid local protrusions that will generate new sources of cavitation. After the construction is completed, a water injection test is used to check the water permeability of the drainage hole. The drainage flow rate of a single hole is required to be not less than 0.5L / min. The negative pressure value of the negative pressure zone is measured on site using a micro-manometer. It is required to be not less than -2kPa. Only after the test is qualified can the next process be carried out.

[0063] This invention solves the key technical problem of not being able to install open drainage holes on the surface of high-velocity drainage channels by arranging water flow guide fins on the upstream side of the drainage hole. Simultaneously, the drainage hole is filled with materials such as gravel, fine sand, and sponge according to the reverse filtration principle, solving the problem of easy clogging. The drainage hole opening is secured with a permeable cap plate via internal threads, which is removable and allows for later replacement of the reverse filtration material inside the hole, ensuring convenient and reliable operation.

[0064] After the high-speed water flow 25 passes through the guide fin, it can form a negative pressure zone at the tail. The negative pressure generated can exert suction on the seepage water in the drainage hole, accelerate the discharge of water from outside the drainage channel, and effectively protect the safety of the drainage channel lining structure.

[0065] This device can install open drainage holes on the surface of the high-velocity drainage channel lining structure and ensure reliable operation of the structure, preventing cavitation erosion damage to the channel surface caused by the installation of drainage holes.

[0066] This device effectively reduces the external water head outside the tunnel lining, significantly reducing the external water pressure on the structure and achieving zero external pressure capability. This allows the tunnel structure to be free from external water pressure, and only the structural requirements need to be met for the tunnel lining structure and reinforcement, while also satisfying the specifications.

[0067] This device solves the problem of reducing external water discharge below the water surface line 4 in high-speed water flow. In particular, when the water flow is 25, an open drainage hole can be set below the water surface line 4, which effectively solves the problem that the open drainage hole will be severely damaged by cavitation and cavitation due to the influence of the high-speed water flow 25, and ensures that the flow channel will not be damaged by cavitation and cavitation.

[0068] The open drainage system of this application is easy to construct, install and manufacture, and has strong applicability. It significantly reduces the thickness of the structural lining and the amount of reinforcement. Engineering application practice has proven that the lining structure of high flow velocity drainage channels can be configured with only a single layer of structural steel reinforcement.

Claims

1. A high-velocity water discharge channel self-priming drainage device, characterized in that... It includes several drainage mechanisms (1) and several guide fins (2). The drainage mechanisms (1) are arranged outside the drainage channel (3) and connected to the drainage hole of the drainage channel (3). The guide fins (2) are arranged inside the drainage channel (3) and set on the upstream side of the drainage hole. The drainage channel (3) is opened in the underground rock mass (6). The air supply pipe is pre-embedded inside the drainage channel (3).

2. The high-velocity water discharge channel self-priming drainage device according to claim 1, characterized in that: The drainage mechanism (1) includes a drainage pipe (15) and a non-woven geotextile (17). Several drainage filter holes (15) are opened on the side wall of the drainage pipe (15). The interior of the drainage pipe (15) is filled with a sponge layer (12), a fine sand layer (13) and a gravel layer (14) from the inlet end to the outlet end. A permeable cap plate (11) is installed on the side of the sponge layer (12) away from the fine sand layer (13). The non-woven geotextile (17) is wrapped around the outside of the drainage pipe (15).

3. The high-velocity drainage channel self-priming drainage device according to claim 2, characterized in that: The permeable cap plate (11) is provided with a number of permeable holes (112) and is equipped with protruding studs (111) for fastening or disassembling the permeable cap plate (11). The opening rate of the permeable holes (112) on the permeable cap plate (11) is not less than 15%, and the diameter of the permeable holes (112) is 3mm ± 0.2mm.

4. The high-velocity water discharge channel self-priming drainage device according to claim 1, characterized in that: The guide fin (2) includes a head cone (21) and a tail blade (22). The head cone (21) is fixedly installed on the side wall of the drainage channel (3) by a steel anchor (23), and the tail blade (22) is connected to the tail end of the head cone (21).

5. The high-velocity water discharge channel self-priming drainage device according to claim 4, characterized in that: The height and width of the guide fin (2) are 1.5 ± 0.2 times the diameter of the drainage hole, the body shape is conical and streamlined, and the length of the tail blade (22) is 2.0 ± 0.2 times the diameter of the drainage hole.

6. A construction method for arranging a high-velocity drainage channel self-priming drainage device according to any one of claims 1-5, characterized in that: Includes the following steps: S1: Measure and lay out the lines, and use lining concrete to pour out the drainage channel (3). After completion and reaching the design strength, lay out and mark the installation positions of the drainage holes and guide fins (2). S2: Drilling construction. After the lining concrete reaches more than 90% of the design strength, drill drainage holes. During the drilling process, use clean water to flush the holes and remove slag, rock powder and concrete debris from the holes. After the holes are formed, conduct through-hole inspection. S3: Drainage pipe fabrication and installation. The length of the drainage pipe (15) is configured according to the actual depth of the drainage hole measured on site and a 20mm to 30mm exposed length is reserved. The pipe wall is covered with several drainage filter holes (16) in a plum blossom pattern. The outside of the drainage pipe is wrapped with a layer of non-woven geotextile and tied and fixed. Then the drainage pipe (15) is inserted into the drainage hole as a whole. After it is inserted into place, the exposed length is checked. S4: The filter material is filled in layers. According to the "reverse filtration principle", the drainage pipe (15) is filled in layers from the inside to the outside, including the sponge layer (12), the fine sand layer (13) and the gravel layer (14). Each layer is lightly compacted after filling. S5: Installation of permeable cap plate After the filter material is filled in layers, install permeable cap plate (11) at the drainage hole opening. S6: Rebar anchor installation: 300mm to 500mm upstream of the drainage hole on the water inlet side, use an impact drill to drill anchor holes, insert rebar anchors (23), use high-strength structural anchoring adhesive for anchoring, and then cure treatment; S7: The guide pier fin is cast in the field using C40 high-performance concrete. The guide pier fin (2) is cast in the field with formwork. The head cone (21) of the guide pier fin (2) has a semi-cone angle of 30° to 45°. After the cast body of the guide pier fin (2) is connected to the steel anchor rod (23) by the rebar, it is covered and watered for curing. S8: Pre-embedding and connecting the air supply pipe. Pre-embedding the PVC air supply pipe at the corresponding position of the negative pressure zone (24) at the tail of the guide pier fin, so that one end of the PVC air supply pipe is connected to the negative pressure zone (24) at the tail, and the other end is led to the external atmospheric side of the drainage channel (3). S9: Surface finishing and inspection. After the construction of the drainage hole and the guide fin is completed, the flow surface (26) of the drainage channel (3) is polished and finished. After the construction is completed, the water injection test is used to test the water permeability of the drainage hole, and the negative pressure value of the tail negative pressure zone (24) is measured on site using a micro pressure gauge. After the inspection is qualified, it can be transferred to the next process.

7. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S1, a total station is used for layout and positioning. The layout deviation of the drainage hole position is ±20mm, and the deviation of the distance between adjacent drainage holes is ±30mm.

8. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S2, the diameter of the drainage hole is 55mm to 60mm, the depth of the drainage hole penetrates the lining structure of the drainage channel (3) and enters the surrounding rock by 50mm to 100mm, and the deviation of the direction of the drainage hole from the normal direction of the flow surface (26) of the drainage channel (3) is ±3°.

9. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S3, the drainage filter hole (16) has a hole diameter of 10mm±1mm, a hole spacing of 50cm±2cm, and an interleaved arrangement angle of 60°±2°; the surface density of the non-woven geotextile is 100g / ㎡~150g / ㎡, and the circumferential overlap width is not less than 100mm; nylon cable ties are used for binding and fixing, and the spacing of the nylon cable ties is 200mm±5mm.

10. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S4, the sponge layer (12) is made of polyurethane sponge with a density of 25-30 kg / m³. 3 The filling thickness accounts for 20% ± 2% of the drainage hole depth; the fine sand layer (13) has a fine sand particle size of 0.5 mm to 2 mm and a filling thickness of 30% ± 2% of the drainage hole depth; the crushed stone layer has a crushed stone particle size of 5 mm to 10 mm and a filling thickness of 40% ± 2% of the drainage hole depth.

11. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S5, the permeable cap plate (11) has internal threads and is tightened with a torque wrench with a torque of 15 N·m to 20 N·m.

12. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S6, the diameter of the anchor hole is 22mm±1mm and the depth is 150mm±2mm; the diameter of the steel anchor rod (23) is 20mm±1mm and the length is 200mm±2mm, and the exposed length of the steel anchor rod (23) is 80mm~100mm; the curing temperature is 20℃ and the curing time is not less than 24 hours; the spacing between two adjacent steel anchor rods (23) along the width direction of the drainage channel (3) is 1.5±0.1 times the diameter of the drainage hole.

13. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S7, the tail blade of the guide pier fin (2) is made of high-performance concrete or stainless steel with a thickness of 8mm to 10mm; it is covered and watered for curing for no less than 7 days, and watered no less than 3 times a day; when stainless steel precast parts are used, they are fully welded to the steel anchor rod (23), and the weld height is no less than 6mm. After welding, the weld is inspected for defects.

14. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S8, temporary sealing measures are taken to prevent debris from blocking the pre-embedded PVC gas supply pipe. After installation, the sealing debris is removed and the pipeline is checked for unobstructed flow.

15. The construction method of the high-velocity drainage channel self-priming drainage device according to claim 6, characterized in that: In step S9, during the grinding and finishing process, the surface flatness error is controlled to be ±5mm / 2m, and the permeability performance of the drainage hole is tested. The single hole drainage flow rate is required to be not less than 0.5L / min, and the negative pressure value is required to be not less than -2kPa.

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