Steel trestle resisting flood season torrent and construction method thereof

Abstract

The present application provides a kind of steel trestle resisting flood season torrent, including steel trestle, steel pipe, anchoring device, one end of anchoring device is anchored on steel support, the other end is anchored in water with concrete and steel pipe lower section and sunk pipe hole together.Steel pipe upper section can be recycled after construction completion, and the occupation time of turnover material is less, and the flat connection of trestle steel pipe pile can also be used as the force transmission structure of anchor beam, and the overall use cost of flood control structure is low.The constraint connection of anchoring device is reliable, and the whole anchoring structure has the property of friction pile, and the rock layer is also fully involved in stress to provide effective constraint by using reaming structure, and the self weight of anchoring body also provides the constraint effect of resisting design flow water load, and the construction method is less affected by geology and topography, and compared with traditional flood control structure stress component, the problem of compression rod stability of long steel pipe under pressure is avoided, and the adaptability is stronger, and the material utilization and turnover rate are improved.

Description

Technical Field

[0001] This invention belongs to the field of steel trestle construction technology, specifically relating to a steel trestle that can resist the rapid currents during the flood season and its construction method. Background Technology

[0002] Traditional steel trestle bridge flood control structures mostly employ vertical flood-resistant piles, connected to existing trestle bridges via composite steel or steel pipe horizontal bracing structures to improve the flood resistance of the steel trestle bridges. However, this traditional method suffers from low material utilization and poor turnover rate in conditions of deep water and high flow velocity, and provides insufficient horizontal restraint. Furthermore, some projects have insufficient horizontal bracing strength, resulting in the steel trestle bridge being washed away after the flood peak, leaving only the flood-resistant piles standing.

[0003] The main reason for this problem is that, under the conditions of rapid current during the flood season, the controlling load of the water pressure affecting the structural safety of the trestle bridge is a horizontal force. According to relevant technical standards, its point of application is located at a depth of 0.3 times the water depth below the water level. Under conditions of great water depth and high flow velocity, due to the large horizontal load and long force arm, the bending moment at the theoretical fixed point of the steel pipe pile is large, which is prone to failure due to insufficient bending strength.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art. This application provides a steel trestle bridge that can withstand the rapid currents during the flood season and its construction method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A steel trestle bridge designed to withstand rapid currents during the flood season includes:

[0008] A steel trestle bridge, on which anchor beams are provided, and on which steel supports are provided above a predetermined flood pressure action surface;

[0009] The steel pipe includes an upper section and a lower section of steel pipe that are detachably spliced ​​together. The upper end of the upper section of steel pipe is used to transfer the excitation force of the sinking pipe to the lower section of steel pipe. The upper section of steel pipe is lifted out after the sinking pipe is completed. The lower section of steel pipe is left in the sinking pipe hole and serves as a steel casing for the soft stratum section during construction and as a component of the anchoring structure after construction is completed.

[0010] An anchoring device, one end of which is anchored to the steel support, and the other end is anchored underwater together with the lower section of the steel pipe and the sinking hole through concrete.

[0011] Preferably, the anchoring device includes:

[0012] A reinforcing cage, wherein the reinforcing cage is cast into the lower section of the steel pipe and into the sinking hole by concrete pouring;

[0013] An anchor cable, one end of which is connected to the reinforcing cage and the other end of which is connected to the steel support;

[0014] An anchor connector is installed between the anchor cable and the steel cage, near the riverbed surface, to adjust the angle of the free section of the anchor cable.

[0015] Preferably, the lower section of the steel pipe and the sinking hole are provided with a positioning steel reinforcement cage that matches the hole diameter, and the positioning steel reinforcement cage is fixedly connected to the steel reinforcement cage;

[0016] An isolation sleeve is fitted onto one end of the anchor cable corresponding to the reinforcing cage, and a rubber sleeve is used to seal the gap between the end of the isolation sleeve and the anchor cable.

[0017] Preferably, the upper edge of the lower section of the steel pipe is provided with multiple sets of limiting plates. The limiting plates include an inner limiting plate and an outer limiting plate disposed on the inner and outer sides of the upper section of the steel pipe. The gap between the inner limiting plate and the outer limiting plate is adapted to the wall thickness of the upper section of the steel pipe.

[0018] Preferably, the lower edge of the lower section of the steel pipe is provided with at least two upwardly extending connecting plates on the outer side, and the upper section of the steel pipe is provided with pre-made slots corresponding to both sides of the connecting plates. Fasteners are provided in the pre-made slots, and the two ends of the fasteners are folded back, with the folded ends extending to the outer side of the connecting plates and the inner side of the upper section of the steel pipe, respectively. A fastening bolt for tightening the outer side of the connecting plates is threaded to the folded part at one end of the fastener.

[0019] A gap is left between the upper and lower sections of the steel pipe when it is hoisted. A push plate is provided in the middle of the outer side of the connecting plate, and the upper edge of the push plate abuts against the fastening bolt.

[0020] After the tube is submerged by applying a vibration force, the upper section of the steel pipe is pressed tightly against the lower section of the steel pipe, and the fastener tilts and detaches from the connecting plate under the push of the push plate.

[0021] This application also provides a construction method for a steel trestle bridge to resist rapid currents during the flood season, wherein the construction of any of the aforementioned steel trestle bridges is characterized by comprising:

[0022] Step S1: Construct the main structure of the steel trestle bridge;

[0023] Step S2: Assemble the upper and lower sections of the steel pipe, hoist and lower them as a whole, and then use a vibratory hammer to excite the steel pipe and perform the pipe sinking operation.

[0024] Step S3: During the steel pipe sinking process, the upper and lower sections of the steel pipe are vibrated by the excitation force to release the connection lock. After the sinking pipe is in place, the upper section of the steel pipe is pulled out for recycling and reuse, while the lower section of the steel pipe remains in the soft stratum to serve as a steel casing for the soft stratum section.

[0025] Step S4: Lower the anchoring device. The lower end of the anchoring device is anchored to the lower section of the steel pipe and inside the sinking pipe hole, while the other end is tensioned on the anchor beam of the steel trestle bridge.

[0026] Preferably, in step S1, the steel pipe piles of the steel trestle bridge are constructed first;

[0027] Longitudinal and transverse horizontal bracing is installed between the steel pipe piles of the steel trestle bridge. Anchor beams and steel supports are welded on the basis of the horizontal bracing. The steel supports are used to connect the anchoring devices and are located above the pre-set flood pressure action surface.

[0028] Sand is backfilled into the steel pipe piles that are directly connected to the anchor beam via a horizontal connection, with the sand filling elevation located above the steel support.

[0029] The main load-bearing crossbeams, Bailey main longitudinal beams, and bridge deck system of the steel trestle bridge were installed in sequence to complete the construction of the steel trestle bridge.

[0030] Preferably, in step S2, the existing structure of the steel trestle bridge is used as a construction guide frame, and the sinker hole is guided to below the rock layer using a drilling device;

[0031] After the steel pipe is in place, the hole is enlarged using a hole enlarging device, with an enlarging angle of not less than 15°.

[0032] After the hole enlargement process is completed, the hole cleaning operation is performed.

[0033] Preferably, in step S4, the anchoring device consists of a steel cage and an anchor cable. The steel cage is located in the lower section of the steel pipe and inside the sinking hole. One end of the anchor cable is connected to the steel cage, and the other end is connected to the steel support.

[0034] Concrete is poured into the lower section of the steel pipe and the sinking hole to form an underwater anchoring structure system together with the anchor cable system, the lower section of the steel pipe, the reinforcing cage and the reinforcing skeleton.

[0035] Preferably, the anchor cable is tensioned after the concrete reaches the specified strength, and the pre-tension value is set to 15% to 30% of the minimum breaking force of the anchor cable. The angle between the anchor cable and the reinforcing cage after tensioning is not greater than 10 degrees.

[0036] Beneficial effects: The upper section of the steel pipe can be recycled and reused after construction is completed, the turnover material occupies less time, and the horizontal connection of the steel pipe pile of the trestle bridge can also serve as the force transmission structure of the anchor beam, resulting in low overall cost of use for the flood-resistant structure.

[0037] The anchoring device has reliable constraint connection, and the entire anchoring structure has the properties of a friction pile. The expansion hole structure allows the rock strata to fully participate in the stress and provide effective constraint. At the same time, the self-weight of the anchor body also provides constraint against the design flow load. Its construction method is less affected by geology and topography. Compared with traditional flood control structural load-bearing components, it avoids the stability problem of compression members under long steel pipes, has stronger adaptability, and improves material utilization and turnover rate. Under the same total construction and use cost, it has higher bearing capacity and has a reinforcing effect on the steel pipe piles of the trestle bridge.

[0038] The construction method of using pre-drilling and cleaning holes before constructing the anchoring structure is less affected by geology and topography during flood control construction and has a wider range of adaptability compared to inclined pile structures. Attached Figure Description

[0039] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0040] Figure 1 This is a schematic diagram of the steel trestle bridge in a specific embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the connection of the anchoring device in a specific embodiment provided by the present invention;

[0042] Figure 3 This is an enlarged schematic diagram of the anchoring device in a specific embodiment provided by the present invention;

[0043] Figure 4 This is a simplified diagram illustrating the connection state between the upper section and the lower end of the steel pipe in a specific embodiment provided by the present invention.

[0044] Figure 5 A simplified diagram of the submerged state of the upper section and lower end of the steel pipe in a specific embodiment provided by the present invention;

[0045] Figure 6 for Figure 4 Sectional view along line AA;

[0046] Figure 7 for Figure 6 Sectional view along the BB direction.

[0047] In the diagram: 1. Steel pipe pile; 2. Horizontal connection; 3. Guide frame; 4. Preset flood pressure action surface; 5. Riverbed surface; 6. Rock surface; 7. Upper section of steel pipe; 8. Lower section of steel pipe; 9. Sinking hole; 10. Anchor beam; 11. Steel support; 12. Reinforcing cage; 13. Anchor cable; 14. Positioning reinforcing cage; 15. Multi-hole anchor; 16. Connecting cable; 17. Anchor connector; 18. Isolation sleeve; 19. Connecting plate; 20. Fastener; 21. Push plate; 22. Fastening bolt; 23. Outer limiting plate; 24. Inner limiting plate. Detailed Implementation

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0049] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0050] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0051] like Figure 1-7As shown, a steel trestle bridge designed to withstand rapid flooding during the flood season includes a steel trestle bridge, steel pipes, and anchoring devices. The main structure of the steel trestle bridge utilizes a fishing-style method of pre-drilled piles and driven piles. The steel pipe piles 1 of the trestle bridge are configured with long and short spans in the longitudinal direction, with two rows of piles in the short spans forming a stable "bench" pile structure to enhance the overall stability of the trestle bridge. Anchor beams 10 are installed on the steel trestle bridge, connected to the steel pipe piles 1 via horizontal bracing 2. Steel supports 11 are installed on the anchor beams 10, located above the pre-set flood pressure action surface 4. The steel pipe includes an upper section 7 and a lower section 8 that are detachably spliced ​​together. The upper end of the upper section 7 is used to transfer the excitation force of the sinking pipe to the lower section 8. After the sinking pipe is completed, the upper section 7 is lifted out, making it a reusable material that can be reused and meets construction requirements. The lower section 8 remains in the sinking pipe hole 9 as a steel casing for the soft stratum section. After construction, it can also be used as part of the anchoring structure, forming a steel pipe concrete pile by pouring, thereby improving its bearing capacity. After the upper section 7 is pulled out, the water pressure on the flood control structure itself is greatly reduced to negligible levels, making its bearing capacity more efficient in resisting the water pressure of the trestle steel pipe pile 1. On the other hand, it eliminates the spatial restriction on the tensioning angle of the free section of the anchor cable 13, improving the efficiency of resisting horizontal water pressure. One end of the anchoring device is anchored to the steel support 11, and the other end is anchored underwater together with the lower section 8 and the sinking pipe hole 9 through concrete.

[0052] In this implementation, the depth of the pilot hole before lowering the steel pipe must penetrate the overburden layer and reach 30-50cm below the top of the rock stratum 6. The diameter of the pilot hole and the distance from the center of the hole to the trestle bridge must be set to ensure that the angle between the free section of the anchor cable 13 and the vertical plane after tensioning at the anchor beam 10 is greater than or equal to 15 degrees.

[0053] The steel pipe is laid to the design elevation. After the lower section 8 of the steel pipe is laid in place, the top surface should be 5500mm above the riverbed surface. After ensuring that the lower section 8 of the steel pipe is stably embedded in the rock strata, drilling and reaming operations can be carried out in the rock strata using pilot hole equipment and hole reaming equipment.

[0054] After the steel pipe pile 1 is installed, install the longitudinal and transverse bridge horizontal bracing 2. Based on the horizontal bracing 2, weld and install the anchor beam 10 and steel support 11. The vertical spacing of the horizontal bracing 2 should be uniform to optimize the stress state of the anchor beam 10.

[0055] In this implementation, the average elevation of the first horizontal brace 2 and the last horizontal brace should be 300-500mm higher than the pre-set flood pressure action surface 4 elevation to reduce the maximum bending moment of the trestle steel pipe pile 1 and optimize the force transmission path. For the trestle steel pipe pile 1 directly connected to the anchor beam 10 supporting the horizontal brace 2, if the steel pipe itself is insufficient in strength and needs reinforcement, it can be reinforced by backfilling sand inside the pipe to 500mm above the anchor point elevation of the free section of the anchor cable 13, thereby improving the shear and compressive bearing capacity of the trestle steel pipe pile 1. If calculations confirm its necessity, the trestle steel pipe directly connected to the anchor beam 10 supporting the horizontal brace 2 can be made of steel pipe with a larger diameter, thicker wall, and higher strength. This ensures that the elevation of the designed water pressure action surface is as close as possible to the elevation of the anchor cable 13 tension point, reducing the maximum bending moment of the trestle steel pipe pile 1, increasing the bearing capacity of the trestle steel pipe pile 1, and improving the effective utilization rate of material strength.

[0056] In an optional embodiment, the anchoring device includes a reinforcing cage 12 and an anchor cable 13. The reinforcing cage 12 is located inside the lower section 8 of the steel pipe and the sinking hole 9. Specifically, the upper half of the reinforcing cage 12 is located inside the lower section 8 of the steel pipe, and the lower half of the reinforcing cage 12 is located inside the sinking hole 9. One end of the anchor cable 13 is connected to the reinforcing cage 12, and the other end is connected to the steel support 11, thereby traction of the steel trestle bridge. In order to ensure the stability of traction, concrete is poured into the lower section 8 of the steel pipe and the sinking hole 9, so that the lower section 8 of the steel pipe, the anchor cable 13, the reinforcing cage 12, the reinforcing steel skeleton, the concrete and the soil layer together constitute an underwater anchoring structure system.

[0057] The reinforcing cage 12 has a certain inclination angle with the lower section 8 of the steel pipe and the axis of the driven hole 9 to increase the horizontal component of the anchor cable 13 force, thereby improving the efficiency of resisting water pressure and flood control performance. In this embodiment, the hole expansion angle is greater than or equal to 15 degrees. During the construction stage, it serves as a protective casing for the weak covering layer when pouring concrete. After construction, it serves as part of the anchoring structure, as a steel pipe concrete pile, and as a confinement structure for the concrete, thereby improving its bearing capacity. After the upper section 7 of the steel pipe is lifted, on the one hand, the water pressure on the flood control structure itself is greatly reduced to negligible levels, allowing its bearing capacity to be used more efficiently to resist the water pressure of the trestle steel pipe pile 1; on the other hand, it eliminates the spatial restriction on the tensioning angle of the free section of the anchor cable 13, thereby improving the efficiency of resisting horizontal water pressure.

[0058] In an optional embodiment, the lower section 8 of the steel pipe and the sinking hole 9 are provided with positioning steel reinforcement cages 14 adapted to their hole diameters. The positioning steel reinforcement cages 14 are used to position the lower section 8 of the steel pipe and the sinking hole 9 to maintain the stability of the reinforcing cage 12. Supporting ribs are evenly distributed inside the positioning steel reinforcement cages 14, and the positioning steel reinforcement cages 14 and the reinforcing cage 12 are fixedly connected by the supporting ribs. One end of the positioning steel reinforcement cages 14 is fixedly connected to the anchor connector 17 corresponding to the anchor cable 13, and the other end is fixedly connected to the multi-hole anchor 15. The anchor connector 17 and the multi-hole anchor 15 are connected by a connecting cable. 16 is connected and prestressed. The connecting cable 16 is connected between the multi-hole anchor 15 and the anchor connector 17. After the anchor and spiral reinforcement of the steel cage 12 and the anchor cable 13 are fixedly connected, the whole structure is sunk to ensure the positioning accuracy of the steel cage 12 and the anchor cable 13. At the same time, as structural reinforcement of concrete, an isolation sleeve 18 is sleeved on one end of the anchor cable 13 corresponding to the steel cage 12, and the gap between the end of the sleeve and the anchor cable 13 is sealed with a rubber sleeve to prevent concrete from pouring in and to prevent the poured concrete from bonding with it, so as to make secondary adjustment of the tension angle of the free section of the anchor cable 13.

[0059] In this embodiment, the steel cage 12 is a column formed by binding steel bars, and reinforcing spiral bars are provided at both ends of the steel cage 12, corresponding to the anchor connector 17 and the multi-hole anchor 15 respectively.

[0060] In an optional embodiment, the upper edge of the lower section 8 of the steel pipe is provided with multiple sets of limiting plates. The limiting plates include an inner limiting plate 24 and an outer limiting plate 23 disposed on the inner and outer sides of the upper section 7 of the steel pipe. The gap between the inner limiting plate 24 and the outer limiting plate 23 is adapted to the wall thickness of the upper section 7 of the steel pipe. The limiting plates guide and constrain the position of the upper and lower sections of the steel pipe so that the pile docking deviation meets the construction requirements. The limiting plates are pre-bent with a pre-bending angle of 2 to 4 degrees to guide the upper section 7 of the steel pipe. The starting point of the pre-bending arc is below the top surface elevation of the lower section 8 of the steel pipe. The limiting plates serve as guides and limiters during the pile docking process of the upper and lower sections of the steel pipe and the subsequent hammering and embedding process.

[0061] In this embodiment, the limiting plates are preferably in groups of 4-6.

[0062] In an optional embodiment, the upper section 7 and the lower section 8 of the steel pipe are connected by a hoisting connecting plate 19 and a clamping friction fastener 20. Before pile driving, the ends of the upper and lower sections of the steel pipe are not in direct contact, and a gap of 3-6 cm should be reserved. In actual construction, the structure of the fastener 20 is not limited, with the principle of ensuring connection reliability and that the jacking plate 21 can effectively release the constraint of the fastener 20 during pile driving. At least two symmetrical connection points about the steel pipe are set to connect the upper section 7 and the lower section 8 of the steel pipe.

[0063] Specifically, the fastener 20 can be a C-shaped or U-shaped bent part. The lower edge of the lower section 8 of the steel pipe is provided with no less than two upwardly extending connecting plates 19. The upper section 7 of the steel pipe is provided with pre-made slots on both sides of the connecting plates 19. The fastener 20 is provided in the pre-made slots. The two ends of the fastener 20 are folded back to form a C-shape. The two folded ends extend to the outside of the connecting plates 19 and the inside of the upper section 7 of the steel pipe, respectively. A fastening bolt 22 is threadedly connected to the folded part at one end of the fastener 20 to tighten the outside of the connecting plates 19. The fastener 20 applies tightening pressure through the bolt. Under the action of this tightening pressure, the friction between the outside of the connecting plates 19 and the inside of the upper section 7 of the steel pipe is used to balance the self-weight of the lower section 8 of the steel pipe, thereby limiting the upper section 7 of the steel pipe and the connecting plates 19. The connection between the two is locked by friction.

[0064] A gap is reserved between the upper section 7 and the lower section 8 of the steel pipe during the hoisting process. After the pipe is submerged, the gap is eliminated, and the upper section 7 and the lower section of the steel pipe are in direct contact. A push plate 21 is provided in the middle of the outer side of the connecting plate 19. The push plate 21 is used to push down and remove the fasteners 20 during the pipe submersion process, so as to facilitate the removal of the upper section 7 of the steel pipe for reuse after the lower section 8 is submerged in place. At the same time, it greatly reduces the water pressure on the flood-resistant structure itself and improves the flood resistance performance of the structure.

[0065] A gap is left between the upper section 7 and the lower section 8 of the steel pipe when they are hoisted. A push plate 21 is provided in the middle of the outer side of the connecting plate 19. The upper edge of the push plate 21 abuts against the fastening bolt 22, so that the gap width between the lower section 8 and the upper section 7 of the steel pipe is 3 to 6 cm, depending on the size of the fastener 20.

[0066] After the steel pipe is positioned and its verticality is checked, the pipe is driven into place. After the pipe is driven into place by applying a vibration force, the upper section 7 of the steel pipe is attached to the lower section 8 of the steel pipe. The fastener 20 tilts and detaches from the connecting plate 19 under the push of the push plate 21.

[0067] This invention also provides a construction method for a steel trestle bridge that resists rapid currents during the flood season, comprising the following steps for constructing any of the aforementioned steel trestle bridges:

[0068] Step S1: Construct the main structure of the steel trestle bridge. The main structure of the steel trestle bridge adopts the fishing method for drilling and pile driving. After the steel pipe pile 1 is installed, install the longitudinal and transverse bridge horizontal bracing 2. Based on the horizontal bracing 2, weld and install the anchor beam 10 and steel support 11. The vertical spacing of the horizontal bracing 2 should be evenly set to optimize the stress state of the anchor beam 10.

[0069] Step S2: Assemble the upper section 7 and the lower section 8 of the steel pipe, and then use vibration force to perform the steel pipe sinking operation.

[0070] The upper section 7 and the lower section 8 of the steel pipe are connected by a hoisting connecting plate 19 and a clamping friction fastener 20. The fastener 20 can be a C-shaped or U-shaped bent part. The lower edge of the lower section 8 of the steel pipe is provided with at least two upwardly extending connecting plates 19. The upper section 7 of the steel pipe is provided with pre-made slots on both sides of the connecting plates 19. The fastener 20 is installed in the pre-made slots. The two ends of the fastener 20 are folded back to form a C-shape. The two folded ends extend to the outside of the connecting plate 19 and the inside of the upper section 7 of the steel pipe, respectively. A fastening bolt 22 is threadedly connected to the folded part at one end of the fastener 20 to tighten the outside of the connecting plate 19. The fastener 20 applies tightening pressure through the bolt. Under the action of this tightening pressure, the friction between the outside of the connecting plate 19 and the inside of the upper section 7 of the steel pipe is used to balance the self-weight of the lower section 8 of the steel pipe, thereby limiting the upper section 7 of the steel pipe and the connecting plate 19. The connection between the two is locked by friction.

[0071] A gap is reserved between the upper section 7 and the lower section 8 of the steel pipe during the hoisting process. After the pipe is submerged, the gap is eliminated, and the upper section 7 and the lower section of the steel pipe are in direct contact. A push plate 21 is provided in the middle of the outer side of the connecting plate 19. The push plate 21 is used to push down and remove the fasteners 20 during the pipe submersion process, so as to facilitate the removal of the upper section 7 of the steel pipe for reuse after the lower section 8 is submerged in place. At the same time, it greatly reduces the water pressure on the flood-resistant structure itself and improves the flood resistance performance of the structure.

[0072] A gap is left between the upper section 7 and the lower section 8 of the steel pipe when they are hoisted. A push plate 21 is provided in the middle of the outer side of the connecting plate 19. The upper edge of the push plate 21 abuts against the fastening bolt 22, so that the gap width between the lower section 8 and the upper section 7 of the steel pipe is 3 to 6 cm, depending on the size of the fastener 20.

[0073] After the steel pipe is positioned and its verticality is checked, the pipe is driven into place. After the pipe is driven into place by applying a vibration force, the upper section 7 of the steel pipe is attached to the lower section 8 of the steel pipe. The fastener 20 tilts and detaches from the connecting plate 19 under the push of the push plate 21.

[0074] After the immersed tube is in place, the upper section 7 of the steel pipe is pulled out for recycling, while the lower section 8 of the steel pipe remains in the soft stratum as a steel casing for the soft stratum section.

[0075] After construction, it serves as part of the anchoring structure, as a steel-concrete composite pile, and as a confinement structure for the concrete, thereby improving its bearing capacity. After the upper section 7 of the steel pipe is lifted, on the one hand, the water pressure on the flood control structure itself is significantly reduced to negligible levels, allowing its bearing capacity to be used more efficiently to resist the water pressure of the trestle steel pipe pile 1; on the other hand, it eliminates the spatial restriction on the tensioning angle of the free section of the anchor cable 13, improving its efficiency in resisting horizontal water pressure.

[0076] Step S4: Lower the anchoring device. The lower end of the anchoring device is anchored to the lower section 8 of the steel pipe and the sinking hole 9, while the other end is tensioned onto the anchor beam 10 of the steel trestle bridge. The anchor connector 17 is located near the riverbed surface 5 to adjust the angle of the free section of the anchor cable 13, thereby increasing the horizontal component of the anchor cable 13 force and improving flood resistance.

[0077] In an optional embodiment, in step S1, the steel pipe piles 1 of the steel trestle bridge are first constructed. The steel pipe piles 1 of the trestle bridge are configured with long and short spans in the longitudinal direction of the bridge. The two rows of piles in the short span form a stable "bench" pile structure to enhance the overall stability of the trestle bridge.

[0078] Longitudinal and transverse horizontal bracing 2 is installed between the steel pipe piles 1 of the steel trestle bridge. Anchor beams 10 and steel supports 11 are welded on the basis of horizontal bracing 2. The steel supports 11 are used to connect the anchoring device and are located above the preset flood pressure action surface 4.

[0079] The average elevation of the first horizontal brace 2 and the last horizontal brace should be 300-500mm higher than the elevation of the design water pressure action surface under the design flood level to reduce the maximum bending moment of the trestle steel pipe pile 1 and optimize the force transmission path. For the trestle steel pipe pile 1 directly connected to the anchor beam 10 supporting the horizontal brace 2, if the steel pipe itself is insufficient in strength and needs reinforcement, it can be reinforced by backfilling sand inside the pipe to 500mm above the anchor point elevation of the free section of the anchor cable 13, thereby improving the shear and compressive bearing capacity of the trestle steel pipe pile 1. If calculations confirm its necessity, the trestle steel pipe directly connected to the anchor beam 10 supporting the horizontal brace 2 can be made of steel pipe with a larger diameter, thicker wall, and higher strength. This will make the elevation of the design water pressure action surface as close as possible to the elevation of the anchor cable 13 tension point, reducing the maximum bending moment of the trestle steel pipe pile 1, increasing the bearing capacity of the trestle steel pipe pile 1, and improving the effective utilization rate of material strength.

[0080] If the steel pipe itself is not strong enough, it needs to be strengthened. The steel pipe pile 1, which is directly connected to the anchor beam 10 through the flat connection 2, is backfilled with sand. The sand filling elevation is above the steel support 11. The backfilling sand reaches 500mm above the steel support 11 elevation to improve the shear and compressive bearing capacity of the trestle bridge steel pipe pile 1.

[0081] The main load-bearing crossbeams, Bailey main longitudinal beams, and bridge deck system of the steel trestle bridge were installed in sequence to complete the construction of the steel trestle bridge.

[0082] In an optional embodiment, in step S2, the existing structure of the steel trestle bridge is used to construct the guide frame. Depending on the location of the anchoring structure, a combination of Bailey beams and steel beams can also be used. The excellent bending stiffness of the Bailey beams is used to increase the working distance, thereby increasing the tension angle of the anchor cable 13 and increasing the proportion of its horizontal component in the resultant force.

[0083] The pilot hole 9 is brought down to below the rock layer 6 using a pilot hole device. Specifically, the pilot hole device is used to penetrate the overburden layer and enter the rock layer 6 30-50cm below the top.

[0084] In this embodiment, depending on the location of the anchoring structure, the guide frame can also be made of a combination of Bailey beams and steel beams. The excellent bending stiffness of the Bailey beams can be used to increase the working distance, thereby increasing the tension angle of the anchor cable 13 and increasing the proportion of its horizontal component in the resultant force.

[0085] After the steel pipe is in place, the hole 9 of the pipe is enlarged using a hole enlarging device. The enlargement angle is not less than 15°. The steel pipe can be used as a protective casing for the weak covering layer when pouring concrete during the construction stage.

[0086] After the hole enlargement process is completed, hole cleaning is carried out. Hole cleaning includes, but is not limited to, hole cleaning with rotary drilling flat bottom bucket and hole cleaning with air lift reverse circulation. After the hole cleaning is completed, the upper section 7 of the steel pipe is lifted out and used as a construction turnover material for the next flood control structure.

[0087] In an optional embodiment, in step S4, the anchoring device consists of a steel cage 12 and an anchor cable 13. The steel cage 12 is located inside the lower section 8 of the steel pipe and the sinking hole 9. One end of the anchor cable 13 is connected to the steel cage 12, and the other end is connected to the steel support 11.

[0088] The anchoring device includes a reinforcing cage 12 and an anchor cable 13. The reinforcing cage 12 is located in the lower section 8 of the steel pipe and the sinking hole 9. Specifically, the upper half of the reinforcing cage 12 is located in the lower section 8 of the steel pipe, and the lower half of the reinforcing cage 12 is located in the sinking hole 9. One end of the anchor cable 13 is connected to the reinforcing cage 12, and the other end is connected to the steel support 11.

[0089] The underwater anchoring structure system is composed of the lower section of steel pipe 8, anchor cable 13, steel cage 12, steel skeleton, concrete and soil layer, which provides passive tensile constraint for the steel trestle bridge and provides horizontal constraint to resist the effect of water pressure, thus achieving good flood control performance.

[0090] The lower section 8 of the steel pipe and the sinking hole 9 are equipped with positioning steel reinforcement cages 14 that are adapted to their hole diameters. During the construction process, the positioning steel reinforcement cages 14 are used to maintain the stability of the sinking of the steel cage 12 and to maintain the design inclination angle, elevation and plane position of the sinking of the steel cage 12. After the concrete pouring is completed, it serves as the internal reinforcement of the anchoring concrete.

[0091] In an optional embodiment, the anchor cable 13 is tensioned after the concrete reaches the specified strength. The pre-tension value is set to 15% to 30% of the minimum breaking force of the anchor cable 13. After tensioning, the angle between the anchor cable 13 and the reinforcing cage 12 is not greater than 10 degrees.

[0092] Specifically, an anchor connector 17 is fixedly connected to one end of the anchor cable 13 corresponding to the positioning steel reinforcement cage 14, and a multi-hole anchor 15 is fixedly connected to the other end. The anchor connector 17 is used to make the angle of the anchor cable 13 after tensioning close to the axial direction of the steel reinforcement cage 12. The anchor connector 17 is set at a position close to the riverbed surface 5 to adjust the angle of the free section of the anchor cable 13, thereby increasing the horizontal component of the force of the anchor cable 13 and improving flood resistance.

[0093] After the concrete has aged for more than 5 days, the free section of the anchor cable 13 is tensioned and fixed to the steel support 11 of the anchor beam 10. The number, diameter, and cross-sectional shape of the anchor cables 13 in the anchoring section and the free section are determined according to the actual stress requirements of the design working conditions.

[0094] The anchorage structure used in this application has a reliable constraint connection and there is no situation where the embedment stability is difficult to meet. The entire anchorage structure has the properties of a friction pile, and the expansion hole structure allows the rock strata to fully participate in the stress and provide effective constraint. At the same time, the self-weight of the anchor body provides a constraint effect against the design flow load. Its construction method is less affected by geology and topography. Compared with the traditional flood control structural load-bearing components, it avoids the stability problem of long steel pipe compression members, has stronger adaptability, and improves material utilization and turnover rate. Under the same total construction and use cost, it has higher bearing capacity and has a reinforcing effect on the trestle bridge steel pipe pile 1.

[0095] The upper section 7 of the steel pipe can be reused and recycled immediately after construction, minimizing the time required for material reuse. Furthermore, the horizontal connection 2 of the steel pipe pile 1 of the trestle bridge can also serve as the force transmission structure for the anchor beam 10, resulting in low overall cost of the flood-resistant structure. The construction method of drilling and cleaning the pre-drilled holes before constructing the anchoring structure minimizes the impact of geological and topographical factors on the flood-resistant construction, offering wider adaptability compared to inclined pile structures. The distance between the expected water flow load and the point of application of the horizontal constraint provided by the trestle bridge is small, significantly reducing the maximum bending moment. The steel pipe pile 1 of the trestle bridge primarily bears vertical pressure, circumferential pressure, and shear force. The triaxial compressive stress, combined with the backfilling of sand or concrete within the pile, fully utilizes the stress performance of different materials, optimizing the stress state of the steel pipe pile 1. With the same materials and structure, the steel pipe pile 1 of the trestle bridge can withstand greater water flow loads, possessing stronger flood control performance and improving material utilization.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be within the scope of protection of the pending claims of the present invention.

Claims

1. A steel trestle bridge that resists rapid currents during the flood season, characterized in that, include: A steel trestle bridge, on which anchor beams are provided, and on which steel supports are provided above a predetermined flood pressure action surface; The steel pipe includes an upper section and a lower section of steel pipe that are detachably spliced ​​together. The upper end of the upper section of steel pipe is used to transfer the excitation force of the sinking pipe to the lower section of steel pipe. The upper section of steel pipe is lifted out after the sinking pipe is completed. The lower section of steel pipe is left in the sinking pipe hole and serves as a steel casing for the soft stratum section during construction and as a component of the anchoring structure after construction is completed. An anchoring device, one end of which is anchored to the steel support, and the other end is anchored underwater together with the lower section of the steel pipe and the sinking hole through concrete. The anchoring device includes: A reinforcing cage, wherein the reinforcing cage is cast into the lower section of the steel pipe and into the sinking hole by concrete pouring; An anchor cable, one end of which is connected to the reinforcing cage and the other end of which is connected to the steel support; An anchor connector is installed between the anchor cable and the steel cage, close to the riverbed surface, to adjust the angle of the free section of the anchor cable; The lower section of the steel pipe has at least two upwardly extending connecting plates on the outer side of its lower edge. The upper section of the steel pipe has pre-made slots corresponding to both sides of the connecting plates. Fasteners are installed in the pre-made slots. The two ends of the fasteners are folded back, and the two folded ends extend to the outer side of the connecting plates and the inner side of the upper section of the steel pipe, respectively. A fastening bolt for tightening the outer side of the connecting plates is threaded onto the folded part at one end of the fastener. A gap is left between the upper and lower sections of the steel pipe when it is hoisted. A push plate is provided in the middle of the outer side of the connecting plate, and the upper edge of the push plate abuts against the fastening bolt. After the tube is submerged by applying a vibration force, the upper section of the steel pipe is pressed tightly against the lower section of the steel pipe, and the fastener tilts and detaches from the connecting plate under the push of the push plate.

2. The steel trestle bridge for resisting rapid currents during the flood season according to claim 1, characterized in that, The lower section of the steel pipe and the sinking hole are provided with a positioning steel reinforcement cage that is adapted to the hole diameter, and the positioning steel reinforcement cage is fixedly connected to the steel reinforcement cage. An isolation sleeve is fitted onto one end of the anchor cable corresponding to the reinforcing cage, and a rubber sleeve is used to seal the gap between the end of the isolation sleeve and the anchor cable.

3. The steel trestle bridge for resisting rapid currents during the flood season according to claim 1, characterized in that, The lower section of the steel pipe is provided with multiple sets of limiting plates along its upper edge. The limiting plates include an inner limiting plate and an outer limiting plate disposed on the inner and outer sides of the upper section of the steel pipe. The gap between the inner limiting plate and the outer limiting plate is adapted to the wall thickness of the upper section of the steel pipe.

4. A construction method for a steel trestle bridge to resist rapid currents during the flood season, comprising constructing the steel trestle bridge according to any one of claims 1-3, characterized in that, include: Step S1: Construct the main structure of the steel trestle bridge; Step S2: Assemble the upper and lower sections of the steel pipe, hoist and lower them as a whole, and then use a vibratory hammer to excite the steel pipe and perform the pipe sinking operation. Step S3: During the steel pipe sinking process, the upper and lower sections of the steel pipe are vibrated by the excitation force to release the connection lock. After the sinking pipe is in place, the upper section of the steel pipe is pulled out for recycling and reuse, while the lower section of the steel pipe remains in the soft stratum to serve as a steel casing for the soft stratum section. Step S4: Lower the anchoring device. The lower end of the anchoring device is anchored to the lower section of the steel pipe and inside the sinking pipe hole, while the other end is tensioned on the anchor beam of the steel trestle bridge.

5. The construction method for a steel trestle bridge resisting rapid floodwaters according to claim 4, characterized in that, In step S1, the steel pipe piles for the steel trestle bridge are constructed first. Longitudinal and transverse horizontal bracing is installed between the steel pipe piles of the steel trestle bridge. Anchor beams and steel supports are welded on the basis of the horizontal bracing. The steel supports are used to connect the anchoring devices and are located above the pre-set flood pressure action surface. Sand is backfilled into the steel pipe piles that are directly connected to the anchor beam via a horizontal connection, with the sand filling elevation located above the steel support. The main load-bearing crossbeams, Bailey main longitudinal beams, and bridge deck system of the steel trestle bridge were installed in sequence to complete the construction of the steel trestle bridge.

6. The construction method for a steel trestle bridge resisting rapid floodwaters according to claim 4, characterized in that, In step S2, the existing structure of the steel trestle bridge is used to construct the guide frame, and the pilot hole is guided to below the rock layer using the pilot hole equipment; After the steel pipe is in place, the hole is enlarged using a hole enlarging device, with an enlarging angle of not less than 15°. After the hole enlargement process is completed, the hole cleaning operation is performed.

7. The construction method for a steel trestle bridge resisting rapid currents during the flood season according to claim 5, characterized in that, In step S4, the anchoring device consists of a steel cage and an anchor cable. The steel cage is located in the lower section of the steel pipe and inside the sinking hole. One end of the anchor cable is connected to the steel cage, and the other end is connected to the steel support. Concrete is poured into the lower section of the steel pipe and the sinking hole to form an underwater anchoring structure system together with the anchor cable system, the lower section of the steel pipe, the reinforcing cage and the reinforcing skeleton.

8. The construction method for a steel trestle bridge resisting rapid floodwaters according to claim 4, characterized in that, After the concrete reaches the specified strength, the anchor cable is tensioned. The pre-tension value is set to 15% to 30% of the minimum breaking force of the anchor cable. After tensioning, the angle between the anchor cable and the reinforcing cage is no greater than 10 degrees.

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