A suspension tunnel outer tube wall spiral spreader device and method of use thereof

Abstract

The present application belongs to the technical field of bridge and tunnel engineering, and particularly relates to a spiral cable spreading device for the outer wall of a suspended tunnel and a method of use. The device is used for temporary storage of anchor cables and simplifies underwater cable spreading construction before the sinking of a suspended tunnel into water, with a prefabricated tunnel pipe section as a unit, the pipe section having two spiral pipes and two pipe section anchor heads installed on the outer wall. The two spiral pipes are installed in parallel along the axial direction of the pipe section in a spiral manner, the surfaces of the two pre-stored anchor cables are coated with a layer of hydrophobic lubricating graphite material, and a traction section is provided at one end of the anchor cable to facilitate smooth threading of the anchor cable into the spiral pipe for temporary storage and underwater extraction and deployment. After the prefabricated tunnel pipe section enters the water, the traction section of the pre-stored anchor cable is anchored to the water bottom foundation, and the other end is anchored to the pipe section anchor head. This method effectively reduces the working hours of underwater construction of the anchor cable and can better ensure the anchoring quality of the anchor cable. After the anchor cable in the spiral pipe is extracted and anchored, the filler can be filled in to suppress vortex-induced vibration of the tunnel.

Description

Technical Field

[0001] This invention belongs to the field of bridge and tunnel engineering, specifically relating to a spiral cable-laying device for the outer wall of a suspended tunnel and its usage method. Background Technology

[0002] A suspended tunnel is a new type of cross-sea transportation structure with a long span and minimal impact on the natural environment. The entire tunnel is completely submerged in water, with both ends connected to the land. Unlike structures such as undersea tunnels, it relies on buoyancy to float in the water. The overall buoyancy-to-weight ratio (the ratio of the buoyancy of the tunnel in the water to its own weight) is adjusted by setting anchor cables or pontoons.

[0003] Anchored suspension tunnels are suitable for waters with depths generally exceeding 100m. At least two anchor cables are arranged every 50-100m, with the anchor cables arranged in an inverted V-shape. One end is anchored to the tunnel body, and the other end is anchored to the seabed foundation. After construction, the tension of the anchor cables balances the difference between the buoyancy and gravity of the tunnel body, preventing excessive deformation of the suspension tunnel body and meeting the requirements for vehicle traffic inside.

[0004] After more than 20 years of research on cable-stayed suspended tunnels, current findings suggest that the general process for suspended tunnels should be: "prefabrication of pipe sections and anchor cables in a dry dock – transport of pipe sections and anchor cables by barge – placement of pipe sections and anchor cables – underwater placement and connection of the pipe sections – fixing of both ends of the anchor cables." Anchor cables, typically 100-200 meters or longer, require significant underwater construction time after being transported to their designated locations by barge, being introduced into the water, deployed, and then pulled to the seabed for anchoring. Theoretical and experimental research in this area is currently very limited, hindering the engineering application of suspended tunnels.

[0005] Based on the above, it is necessary to propose a construction method for anchor cable transportation, underwater cable laying, and anchoring that is conducive to improving the anchoring quality and saving time and resources. Summary of the Invention

[0006] The purpose of this invention is to provide a spiral cable deployment device for the outer wall of a suspended tunnel and its method of use. This device eliminates the need to separately transport the anchor cables underwater, accelerating the underwater construction progress and making underwater cable deployment and anchoring more economical and convenient. Furthermore, after the suspended tunnel is completed, the device is permanently retained on the tunnel body, becoming part of the tunnel structure, and can play a role in resisting wave and current loads and improving the overall structural rigidity.

[0007] The technical solution of the present invention is as follows: The prefabricated tunnel segment with a spiral anchor cable pre-storage device on the outer wall is used as a unit for temporary storage of anchor cables before the suspended tunnel sinks into the water, simplifying underwater cable laying construction; a single prefabricated tunnel segment includes the segment body, two spiral pipes, two segment anchor heads and two pre-stored anchor cables; The method of use includes the following steps: S1: Based on the length and diameter of the pipe section and the corresponding lengths of the two pre-stored anchor cables, calculate the pitch h and the number of turns n of the two spiral pipes; fabricate two spiral pipes of equal length and pitch and then connect them side by side; the length of the spiral pipe is greater than the length of the pre-stored anchor cable. S2: Precast tunnel segments are fabricated in a dry dock. If the outer wall of the segment is made of concrete, the two segment anchors need to be custom-made with formwork to complete the concrete pouring, and the two metal spiral pipes are permanently fixed to the outer wall of the segment with bolts. If the outer wall of the segment is made of steel, the two segment anchors are also made of steel and are welded to the outer wall of the segment together with the two parallel metal spiral pipes. The segment anchors are prefabricated in a dry dock, which can reduce underwater construction and control the anchoring quality. S3: The surfaces of the two pre-stored anchor cables are coated with a layer of graphite material and completely inserted into the two spiral tubes. They are temporarily stored along the spiral guide path. The ends of the spiral tubes are temporarily sealed for waterproofing. No pretension is applied to the anchor cables during the temporary storage state. S4: Float the prefabricated tunnel sections and sink them to the predetermined underwater depth; thus saving the time of separately transporting the anchor cables to the underwater surface; S5: Remove the temporary seals at both ends of the spiral pipe, slowly pull the traction section of the pre-stored anchor cable to the underwater foundation, control the vertical component of the traction section speed to be 0.2-0.5m / s, and unfold the pre-stored anchor cable; permanently anchor the traction section to the foundation, and anchor the other end of the pre-stored anchor cable to the pipe section anchor head; S6: Complete the segment-by-segment connection of other precast tunnel sections according to the above steps; fill the spiral pipe with lightweight foamed concrete filler and seal the ends to improve the strength of the spiral pipe; during the operation of the suspended tunnel, the spiral pipe can disrupt the periodic vortex shedding caused by the ocean current flowing through the suspended tunnel, thereby suppressing the tunnel vortex-induced vibration.

[0008] The prefabricated tunnel section has two hollow circular spiral tubes on its outer wall, made of high-strength, rust-resistant alloy material. The spiral tube units are connected by flange joints or welding to form a continuous spiral guide cavity. The projected length of the two spiral tubes along the pipe axis is u1, and the length of the pipe section body is u, u1 / u=0.7-0.8. The prefabricated tunnel section has two spiral tube cavities with a diameter of d1, each storing two pre-stored anchor cables to limit tunnel deformation. The diameter of the pre-stored anchor cables is d2, where d2 / d1 = 0.8-0.9. Sufficient clearance is maintained between the pre-stored anchor cables and the spiral tubes, while avoiding excessive local bending of the pre-stored anchor cables during temporary storage. The surface of the pre-stored anchor cables is coated with a hydrophobic lubricating graphite material layer of thickness t, where d2+2t<0.95d1. This ensures that even after coating with the graphite material layer, there is still radial clearance to accommodate dimensional errors of the components and local bending deformation of the pre-stored anchor cables. One end of the pre-stored anchor cable has a traction section of length d3, where d3 / d2 = 10-15, with its diameter gradually decreasing. This facilitates the smooth insertion of the pre-stored anchor cable from the end of the spiral tube for temporary storage and reduces resistance during underwater traction. The prefabricated tunnel segment has two segment anchors arranged on the horizontal sides of the segment body and flush with one end of the two spiral pipes. The length of the segment anchor from one end of the segment body is u2, u2 / u=0.15-0.2, in order to reduce the bending moment and shear force at the joint of adjacent segments during the operation of the suspended tunnel.

[0009] The beneficial effects of this invention are as follows: 1) The anchor cable is inserted into the spiral tube and transported to the predetermined underwater position before being laid and anchored, realizing "anchor cable pre-storage + spiral tube guided cable laying", which simplifies the complex underwater cable insertion and laying operations, shortens the construction period, saves costs, and controls construction risks; 2) The anchor head of the pipe section is prefabricated in the dry dock and is already connected to the pipe section before it is launched into the water, which simplifies the underwater construction of the anchor head and improves the anchoring quality of the anchor cable; the spiral pipe guide arrangement makes the release path and process of the anchor cable controllable, and the anchor cable is tensioned in stages to gradually establish the predetermined anchor cable tension. 3) Installing the spiral pipe on the outer wall of the suspended tunnel section reduces the direct impact and erosion of the outer pipe wall by the wave flow; filling the spiral pipe with filler increases the strength and rigidity of the pipe section body, weakens vortex-induced vibration, and improves the vibration resistance stability of the suspended tunnel. 4) The huge tension of the anchor cable will cause the pipe section near the anchor cable installation position to bear a lot of shear force and negative bending moment. There are few reports on the "reasonable installation position of anchor cable on pipe section". By adopting the method of the present invention, the pipe section joint and the anchor cable installation position are staggered, so that the negative bending moment section and the pipe section joint are also staggered, which is conducive to improving the service life of the suspended tunnel joint. Attached Figure Description

[0010] Figure 1 This is an overall schematic diagram of the prefabricated tunnel segment of the present invention; Figure 2 Elevation view of the precast tunnel segment during anchor cable installation; Figure 3 A side view of a prefabricated tunnel segment after anchor cable installation; Figure 4 for Figure 1 A cross-sectional view of two spiral pipes installed on the outer wall of a precast tunnel segment, wherein, Figure 4 (a) shows the state in which the pre-stored anchor cable is temporarily stored inside the spiral tube. Figure 4 (b) shows the state of the filler material in the spiral tube after anchoring; Figure 5 middle Figure 1 Detailed view of the pipe section anchor head; The structure shown in the diagram is as follows: 1. Pipe section body, 2. Spiral pipe, 3. Pipe section anchor head, 4. Pre-stored anchor cable, 401. Traction section, 5. Graphite material layer, 6. Temporary seal, 7. Lightweight foamed concrete filler. Detailed Implementation

[0011] The specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0012] like Figures 1-3 As shown, the prefabricated tunnel segment with a spiral anchor cable pre-storage device on the outer wall is used as a unit for temporary storage of anchor cables before the suspended tunnel sinks into the water, simplifying underwater cable laying construction; a single prefabricated tunnel segment includes the segment body 1, two spiral pipes 2, two segment anchor heads 3 and two pre-storage anchor cables 4. like Figure 1 , Figure 2 As shown, the two spiral tubes 2 on the outer pipe wall have hollow circular cross sections and are made of high-strength, rust-resistant alloy material. The units of the spiral tubes 2 are connected by flange joints or welding to form a continuous spiral guide cavity. The projected length of the two spiral tubes 2 along the pipe body axis is u1, and the length of the pipe body 1 is u, u1 / u=0.7-0.8. like Figure 1 , Figure 2 and Figure 4 As shown, the two spiral tubes 2 have cavities with diameters of d1, which respectively store two pre-stored anchor cables 4 used to limit tunnel deformation. The diameter of the pre-stored anchor cables 4 is d2, and d2 / d1=0.8-0.9. The surface of the pre-stored anchor cables 4 is coated with a hydrophobic lubricating graphite material layer 5 with a thickness of t, d2+2t<0.95d1. One end of the pre-stored anchor cables 4 is provided with a traction section 401 of length d3, d3 / d2=10-15, whose diameter gradually decreases, which is conducive to the smooth insertion of the pre-stored anchor cables 4 from the end of the spiral tubes 2 for temporary storage and to reduce resistance during underwater traction. like Figures 1-5 As shown, two pipe segment anchor heads 3 are respectively arranged on the horizontal sides of the pipe segment body 1 and are flush with one end of the two spiral pipes 2. The length of the pipe segment anchor head 3 from one end of the pipe segment body 1 is u2, u2 / u=0.15-0.2, so as to reduce the bending moment and shear force at the joint of adjacent pipe segments during the operation of the suspended tunnel. The method of use includes the following steps: S1: Based on the length and diameter of the pipe section 1 and the lengths of the two pre-stored anchor cables 4, calculate the pitch h and the number of turns n of the two spiral pipes 2; make two spiral pipes 2 of equal length and pitch and then connect them side by side; the length of the spiral pipe 2 is greater than the length of the pre-stored anchor cable 4; S2: Precast tunnel segments are manufactured in a dry dock. If the outer wall of the segment body 1 is made of concrete, the two segment anchor heads 3 need to be custom-made with templates to complete the concrete pouring, and the two metal spiral pipes 2 are permanently fixed to the outer wall of the segment with bolts. If the outer wall of the segment body 1 is made of steel, the two segment anchor heads 3 are also made of steel and are welded to the outer wall of the segment together with the two parallel metal spiral pipes 2. The segment anchor heads 3 are precast in a dry dock, which can reduce underwater construction and control the anchoring quality. S3: Two pre-stored anchor cables 4 are coated with a graphite material layer 5 and completely inserted into two spiral tubes 2. They are temporarily stored along the spiral guide path. Temporary seals 6 are set at both ends of the spiral tubes 2. The temporary seals 6 adopt an inflatable sealing plug structure and are fixed to the port of the spiral tubes 2 by clamps to achieve waterproofing. No pretension is applied to the anchor cables in the temporary storage state. S4: Float the prefabricated tunnel sections and sink them to the predetermined underwater depth; thus saving the time of separately transporting the anchor cables to the underwater surface; S5: The diver descends to section 1 of the pipe body, removes the temporary seals 6 at both ends of the spiral pipe 2, and the underwater robot slowly pulls the traction section 401 of the pre-stored anchor cable 4 to the underwater foundation. The vertical component of the speed of the traction section 401 is controlled to be 0.2-0.5 m / s, and the pre-stored anchor cable 4 is deployed. The traction section 401 is permanently anchored to the foundation, and the other end of the pre-stored anchor cable 4 is anchored to the pipe section anchor head 3. S6: Complete the segment-by-segment connection of other precast tunnel sections according to the above steps; after the pre-stored anchor cable 4 is deployed and anchored, lightweight foamed concrete filler 7 is pumped from the water into the spiral pipe 2 through the external pipeline. After the filler is filled, waterproof concrete is used to permanently seal the port of the spiral pipe 2 to improve the strength of the spiral pipe 2; during the operation of the suspended tunnel, the spiral pipe 2 can destroy the periodic vortex shedding caused by the ocean current flowing through the suspended tunnel, and play a role in suppressing the tunnel vortex-induced vibration.

Claims

1. A method for using a spiral cable-laying device for the outer wall of a suspended tunnel, characterized in that, Using prefabricated tunnel sections with spiral anchor cable pre-storage devices on the outer wall as units, it is used for temporary storage of anchor cables before the suspended tunnel sinks into the water and simplifies underwater cable deployment and installation; The prefabricated tunnel segment includes a segment body (1), two spiral pipes (2), two segment anchor heads (3) on the outer wall of the pipe, and two pre-stored anchor cables (4); the two spiral pipes (2) are spirally wound in parallel on the outer wall of the segment body (1) along the axial direction of the segment. The method of use includes the following steps: S1: Based on the length and diameter of the pipe section body (1) and the length of the two pre-stored anchor cables (4) corresponding to it, calculate the pitch h and the number of winding turns n of the two spiral pipes (2); make two spiral pipes (2) of equal length and equal pitch and then connect them side by side; the length of the spiral pipe (2) is greater than the length of the pre-stored anchor cable (4); S2: Precast tunnel segments are made in a dry dock. If the outer wall of the segment body (1) is made of concrete, the two segment anchors (3) need to be custom-made with templates to complete the concrete pouring. The two metal spiral pipes (2) are permanently fixed to the outer wall of the segment with bolts. If the outer wall of the segment body (1) is made of steel, the two segment anchors (3) are also made of steel and are welded to the outer wall of the segment together with the two parallel metal spiral pipes (2). The segment anchors (3) are precast in a dry dock, which can reduce underwater construction and control the anchoring quality. S3: The two pre-stored anchor cables (4) are coated with a graphite material layer (5) and completely inserted into the two spiral tubes (2). They are temporarily stored along the spiral guide path. The ends of the spiral tubes (2) are temporarily sealed (6) for waterproofing. No pretension is applied to the anchor cables in the temporary storage state. S4: Float the prefabricated tunnel sections and sink them to the predetermined underwater depth; thus saving the time of separately transporting the anchor cables to the underwater surface; S5: Remove the temporary seals (6) at both ends of the spiral pipe (2), slowly pull the traction section (401) of the pre-stored anchor cable (4) to the bottom foundation, control the vertical component of the speed of the traction section (401) to be 0.2-0.5m / s, and the pre-stored anchor cable (4) unfolds; the traction section (401) is permanently anchored to the foundation, and the other end of the pre-stored anchor cable (4) is anchored to the pipe section anchor head (3). S6: Complete the segment-by-segment connection of other precast tunnel sections according to the above steps; fill the spiral pipe (2) with lightweight foamed concrete filler (7) and seal the end to improve the strength of the spiral pipe (2); during the operation of the suspended tunnel, the spiral pipe (2) can destroy the periodic vortex shedding caused by the ocean current flowing through the suspended tunnel, and play the role of suppressing the tunnel vortex-induced vibration.

2. A spiral cable-laying device for the outer wall of a suspended tunnel for implementing the method of claim 1, characterized in that, The precast tunnel section has two spiral pipes (2) on the outer wall with hollow circular cross sections, made of high-strength, rust-resistant alloy material. The spiral pipes (2) are connected to each other by flange joints or welding to form a continuous spiral guide cavity. The two spiral pipes (2) have a projected length of u1 along the pipe axis, and the length of the pipe section body (1) is u, u1 / u=0.7-0.

8. The prefabricated tunnel section has two spiral tubes (2) with a cavity diameter of d1, which respectively store two pre-stored anchor cables (4) used to limit tunnel deformation. The diameter of the pre-stored anchor cables (4) is d2, d2 / d1=0.8-0.

9. The surface of the pre-stored anchor cables (4) is coated with a hydrophobic lubricating graphite material layer (5) with a thickness of t, d2+2t<0.95d1. One end of the pre-stored anchor cables (4) is provided with a traction section (401) with a length of d3, d3 / d2=10-15, whose diameter gradually decreases, which is conducive to the smooth insertion of the pre-stored anchor cables (4) from the end of the spiral tubes (2) into the temporary storage and to reduce resistance during underwater traction. The precast tunnel segment has two segment anchors (3) arranged on the horizontal sides of the segment body (1) and flush with one end of the two spiral pipes (2). The length of the segment anchor (3) from one end of the segment body (1) is u2, u2 / u=0.15-0.2, so as to reduce the bending moment and shear force at the joint of adjacent segments during the operation of the suspended tunnel.

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