Prestressed immersed tube joint, design method and SPMT on-vehicle barge method

Abstract

The invention relates to a prestressed immersed tube joint, a design method and an SPMT on-vehicle barge method. According to the prestressed immersed tube joint, the transverse first prestressed steel beams are arranged in the bottom plate of the prestressed immersed tube joint, so that all the parts of the bottom plate can meet the supporting conditions of SPMT vehicles, then the SPMT vehicles can be fully distributed below the bottom plate, and enough supporting force can be provided when the SPMT vehicles are used for transporting the prestressed immersed tube joint; the cracking degree of the prestressed immersed tube joints can be reduced, so that the immersed tube joints can be transported by adopting an SPMT vehicle; the transverse second prestressed steel beam is arranged in the top plate, the second prestressed steel beam can overcome the stress influence of the first prestressed steel beam on the top plate, the arrangement form of the first prestressed steel beam and the second prestressed steel beam conforms to the load bearing form of the bottom plate and the top plate of the immersed tube joint in the operation period, and the stress state of the immersed tube joint in the operation period is met; the reinforcement quantity of the bottom plate and the top plate can be reduced, and the cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of immersed tube barge-in, and in particular to a prestressed immersed tube segment, a design method and a SPMT vehicle barge-in method. Background Art

[0002] In the prior art, for a reinforced concrete immersed tube segment, when it is moved from the dock to a semi-submersible barge, it is necessary to set up a row of transport trolleys under the side walls and the middle wall of the immersed tube segment. However, the adjustment stroke of the support height of the transport trolley is small and the adaptive ability is poor, which is not conducive to crack control during the barge process. The SPMT vehicle has a large-stroke adaptive adjustment ability and walking flexibility. Compared with the use of a transport trolley, the use of the SPMT vehicle can reduce the difficulty of crack control of the immersed tube segment during the floating barge process.

[0003] However, the use of SPMT vehicles will face new technical problems:

[0004] The SPMT vehicle has a small carrying capacity and a large size, while the immersed tube segment is heavy, so more SPMT vehicle groups are needed, which basically need to be fully laid under the immersed tube segment. However, the existing immersed tube segment is designed only based on operational requirements, and its supporting area is small. It can only be supported on the bottom plate corresponding to the middle wall and side wall area. The SPMT vehicle group cannot be arranged to support the bottom plate corresponding to the area between the middle wall and the side wall. The SPMT vehicle group is only laid on the bottom plate corresponding to the middle wall and side wall area, which makes the SPMT vehicle group unable to meet the carrying conditions, and thus the SPMT vehicle cannot be used to transport the immersed tube segment. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art of reinforced concrete immersed tube segments, in which the SPMT vehicle group can only be laid on the bottom plates corresponding to the middle wall and side wall areas of the immersed tube segments, and the bearing conditions cannot be met, and thus the SPMT vehicle cannot be used to transport the immersed tube segments. A prestressed immersed tube segment, a design method and an SPMT vehicle barge method are provided.

[0006] In a first aspect, the present invention provides a prestressed immersed tube joint, comprising a top plate, a bottom plate, a first side wall, a first middle wall, a second middle wall, and a second side wall, wherein the first side wall, the first middle wall, the second middle wall, and the second side wall are sequentially arranged along the transverse direction of the immersed tube joint, and comprise a first prestressed steel strand and a second prestressed steel strand;

[0007] The first prestressed steel strands are arranged in the bottom plate, the first prestressed steel strands are arranged transversely along the bottom plate, and the first prestressed steel strands are distributed at intervals longitudinally along the bottom plate;

[0008] The first prestressed steel strand includes a first passing point, a second passing point, a third passing point, a fourth passing point and a fifth passing point, the first passing point is located below the first side wall, the second passing point is located between the first side wall and the first middle wall, the third passing point is located between the first middle wall and the second middle wall, the fourth passing point is located between the second middle wall and the second side wall, and the fifth passing point is located below the second side wall, the first prestressed steel strand is vertically arranged in a wave shape, the first passing point, the third passing point and the fifth passing point are wave troughs, and the second passing point and the fourth passing point are wave crests;

[0009] The second prestressed steel strands are arranged in the top plate, the second prestressed steel strands are arranged transversely along the top plate, and the second prestressed steel strands are distributed at intervals longitudinally along the top plate;

[0010] The second prestressed steel bundle includes a sixth passing point, a seventh passing point, an eighth passing point, a ninth passing point and a tenth passing point. The sixth passing point is located above the first side wall, the seventh passing point is located between the first side wall and the first middle wall, the eighth passing point is located between the first middle wall and the second middle wall, the ninth passing point is located between the second middle wall and the second side wall, and the tenth passing point is located above the second side wall. The second prestressed steel bundle is arranged in a wave shape in the vertical direction. The sixth passing point, the eighth passing point and the tenth passing point are located at the crest of the wave, and the seventh passing point and the ninth passing point are located at the trough of the wave.

[0011] A transverse first prestressed steel bundle is arranged in the bottom plate of the prestressed immersed tube segment and is spaced longitudinally along the prestressed immersed tube segment to meet the longitudinal support conditions, and the transverse first prestressed steel bundle has a first passing point corresponding to the first side wall, a second passing point corresponding to between the first side wall and the first middle wall, a third passing point corresponding to between the first middle wall and the second middle wall, a fourth passing point corresponding to between the second middle wall and the second side wall, and a fifth passing point corresponding to the second side wall, and the first prestressed steel bundle is arranged in a wave shape in the vertical direction, the first passing point, the third passing point and the fifth passing point are troughs, and the second passing point and the fourth passing point are peaks, so that all parts of the bottom plate can meet the support conditions of the SPMT vehicle, and then the SPMT vehicles can be fully distributed under the bottom plate, so that the use of the SPMT vehicle to transport the prestressed immersed tube segment can provide sufficient support force and can reduce the degree of cracking of the prestressed immersed tube segment, and then the SPMT vehicle can be used to transport the immersed tube segment by barge.

[0012] However, the setting of the first prestressed steel bundle will cause the middle wall position corresponding to the top plate to arch upward, that is, the stress of the top plate will be affected. By setting a transverse second prestressed steel bundle in the top plate, the second prestressed steel bundle can overcome the stress influence of the first prestressed steel bundle on the top plate, and the setting form of the first prestressed steel bundle and the second prestressed steel bundle conforms to the load form of the bottom plate and the top plate of the immersed tube section during the operation period, meets the stress state of the immersed tube section during the operation period, and can also reduce the reinforcement amount of the bottom plate and the top plate, thereby saving costs.

[0013] Preferably, the first passing point and the fifth passing point are arranged at the vertical center of the bottom plate, and the sixth passing point and the tenth passing point are arranged at the vertical center of the top plate, so as to facilitate tensioning;

[0014] And / or, the distances between the second and fourth passing points and the top surface of the bottom plate are both greater than or equal to the thickness of the steel bar protective layer on the top surface of the bottom plate, the distance between the third passing point and the bottom surface of the bottom plate is greater than or equal to the thickness of the steel bar protective layer on the bottom surface of the bottom plate, the distances between the seventh and ninth passing points and the bottom surface of the top plate are greater than or equal to the thickness of the steel bar protective layer on the bottom surface of the top plate, and the distance between the eighth passing point and the top surface of the top plate is greater than or equal to the thickness of the steel bar protective layer on the top surface of the top plate, so as to ensure the safety of the structural force;

[0015] And / or, the first prestressed steel strand and the second prestressed steel strand are both smooth curves, thereby improving the quality of prestressing;

[0016] And / or, the first prestressed steel bundle and the second prestressed steel bundle are arranged symmetrically in the transverse direction of the immersed tube section, which can better adapt to the transverse balanced arrangement of the immersed tube joint.

[0017] In a second aspect, the present invention provides a design method for a prestressed immersed tube segment, which is used for a prestressed immersed tube segment, comprising the following steps:

[0018] S01: Determine the preset position range of the onboard support for supporting the prestressed immersed tube segment on the semi-submersible barge and the fixed piers during the prefabrication of the prestressed immersed tube segment, and exclude the lateral position of the prestressed immersed tube segment when the SPMT vehicle transports the prestressed immersed tube segment according to the preset position range of the onboard support and the fixed pier; then determine the number of required SPMT vehicles according to the weight of the prestressed immersed tube segment; then obtain all the layout position points of the required SPMT vehicles corresponding to the prestressed immersed tube segment according to the number of required SPMT vehicles, excluding the lateral position of the SPMT vehicle when transporting the prestressed immersed tube segment, and the layout requirements; in step S01, the layout requirements are: arrange the SPMT vehicles in a row below the prestressed immersed tube segment, and arrange the SPMT vehicles symmetrically in the transverse direction of the prestressed immersed tube segment;

[0019] S02: Determine the cross-sectional design of the first prestressed steel strand and the second prestressed steel strand according to the layout position of the SPMT vehicle and the longitudinal setting position of the prestressed immersed tube segment, and the design of the prestressed immersed tube segment is completed.

[0020] It can meet the requirements of SPMT vehicles transporting prestressed immersed tube segments fully under the bottom plate and the structural safety requirements of immersed tube segments.

[0021] Preferably, step S02 includes the following steps:

[0022] S02.1: Obtain an equivalent immersed tube unit with the longitudinal direction as the unit length. The bottom plate, top plate, middle wall and side wall of the equivalent immersed tube unit are all equivalent to beam units, and the beam units are rigidly connected;

[0023] S02.2: Determine the position where the support force is applied at the bottom of the equivalent immersed tube unit according to the layout position of the SPMT vehicle, simulate the support of the SPMT vehicle on the equivalent immersed tube unit, and establish a simplified calculation model of the equivalent immersed tube unit;

[0024] S02.3: Analyze the force form of the simplified calculation model under the combined action of the support force and the gravity of the equivalent immersed tube unit, and obtain the first bending moment diagram;

[0025] S02.4: A first prestressed steel strand and a second prestressed steel strand of a prestressed immersed tube segment as claimed in any one of claims 1 to 2 are added to the bottom plate and the top plate of the equivalent immersed tube unit respectively;

[0026] S02.5: Then, the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand are changed, and the force form of the simplified calculation model under the combined action of the supporting force, the prestress provided by the first prestressed steel strand, the prestress provided by the second prestressed steel strand, and the gravity of the equivalent immersed tube unit is analyzed to obtain the second bending moment diagram;

[0027] S02.6: Determine the bending moments of the bottom plate and top plate of the equivalent immersed tube unit. If the bending moments of the bottom plate in the second bending moment diagram except for the connection between the bottom plate and the side wall are not greater than the preset bending moment, and the bending moment of the top plate in the second bending moment diagram is not greater than the bending moment of the top plate in the first bending moment diagram, then the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand meet the force requirements of the equivalent immersed tube unit, and obtain the relationship between the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand and the unit length, and enter S02.7. Otherwise, repeat steps S02.5 and S02.6 until entering S02.7;

[0028] S02.7: Select the number of steel strands and the longitudinal spacing of the first prestressed steel tendons and the second prestressed steel tendons based on the relationship between the cross-sectional area and the unit length of the first prestressed steel tendons and the second prestressed steel tendons that meet the requirements;

[0029] S02.8: Establish a finite element model for the transportation of prestressed immersed tube segments by SPMT vehicles based on the number of steel strands and longitudinal spacing of the selected first prestressed steel strands and the second prestressed steel strands;

[0030] S02.9: Analyze whether the stress on the prestressed immersed tube segment meets the crack control requirements. If so, complete the prestressing design and determine the cross-sectional design of the first prestressed steel strand and the second prestressed steel strand as well as their longitudinal setting positions of the prestressed immersed tube segment. If not, readjust the number of steel strands in the load bundle or the longitudinal arrangement spacing and repeat steps S02.8 and S02.9 until the stress on the immersed tube segment meets the crack control requirements. Complete the prestressing design and obtain the cross-sectional design of the first prestressed steel strand and the second prestressed steel strand as well as their longitudinal setting positions of the prestressed immersed tube segment.

[0031] The above method can adjust the number of steel strands and the longitudinal arrangement spacing of the first prestressed steel bundle and the second prestressed steel bundle by obtaining the relationship between the cross-sectional area and the unit length of the first prestressed steel bundle and the second prestressed steel bundle that meet the requirements, so as to obtain the cross-sectional design of the first prestressed steel bundle and the second prestressed steel bundle that better meet the requirements and the longitudinal setting position of the prestressed immersed tube segment.

[0032] In a third aspect, the present invention provides a method for loading a SPMT vehicle, which is used for loading a prestressed immersed tube segment, comprising the following steps:

[0033] S1, determine the preset position range of the onboard support on the semi-submersible barge for supporting the prestressed immersed tube segment and the fixed piers when the prestressed immersed tube segment is prefabricated, and exclude the lateral position of the prestressed immersed tube segment when the SPMT vehicle transports the prestressed immersed tube segment according to the preset position range of the onboard support and the fixed pier; then determine the number of required SPMT vehicles according to the weight of the prestressed immersed tube segment; then obtain all the layout position points of the required SPMT vehicles corresponding to the prestressed immersed tube segment according to the number of required SPMT vehicles, excluding the lateral position of the SPMT vehicle when transporting the prestressed immersed tube segment, and the layout requirements; in step S1, the layout requirements are: arrange the SPMT vehicles in a row below the prestressed immersed tube segment, and arrange the SPMT vehicles symmetrically in the transverse direction of the prestressed immersed tube segment;

[0034] S2. Arranging the SPMT cars at the bottom of the prestressed immersed tube segment according to the arrangement positions of the SPMT cars, each row of the SPMT cars forms a train set, and sleepers are arranged on the train set;

[0035] S3. Lift the prestressed immersed tube segment by the SPMT vehicle so that the prestressed immersed tube segment is separated from the fixed pier;

[0036] S4, use the SPMT vehicle to drive the prestressed immersed tube segment from the prefabrication plant to the semi-submersible barge via the dock;

[0037] S5. The SPMT vehicle supports the hydraulic cylinder to lower the prestressed immersed tube segment until it falls on the support on the ship;

[0038] S6, the SPMT car support hydraulic cylinder continues to descend so that the sleepers do not touch the submerged tube section;

[0039] S7. The SPMT vehicle was returned to the wharf and the loading of the prestressed immersed tube section was completed.

[0040] The purpose of setting the sleepers is to prevent the SPMT vehicle from directly contacting the prestressed immersed tube segments, and to avoid a large cracking process caused by direct contact between the steel structure SPMT vehicle and the concrete of the prestressed immersed tube segments.

[0041] The above-mentioned SPMT vehicle barge method is adopted, which sets transverse prestress on the bottom plate of the immersed tube segment, so that the SPMT vehicle can be fully arranged under the bottom plate; after the layout position of the SPMT vehicle is determined, it can meet the support of the prestressed immersed tube segment and the bearing capacity during barge; and the transverse position of the SPMT vehicle at the prestressed immersed tube segment is staggered with the transverse position of the prestressed immersed tube segment corresponding to the fixed pier, so that after the prestressed immersed tube segment is prefabricated, the SPMT vehicle can be arranged under the prefabricated prestressed immersed tube segment, so as to realize the force conversion between the fixed pier and the SPMT vehicle; and the SPMT vehicle is staggered at the prestressed immersed tube segment. The lateral position of the section is staggered with the lateral position of the prestressed immersed tube section corresponding to the support on the ship, so that the SPMT vehicle can transport the prestressed immersed tube section from the dock to the semi-submersible barge without being disturbed by the support on the ship, and then the prestressed immersed tube section can be converted from the sleeper support on the SPMT vehicle to the support on the ship, and the SPMT vehicle continues to unload the force, so that the top of the vehicle group does not contact the immersed tube section, so that the SPMT vehicle can be returned to the dock, and then the SPMT vehicle is used to realize the overall barge process of the prestressed immersed tube section. This process reduces the difficulty of controlling the cracking of the immersed tube section during the barge process due to the large stroke adaptive adjustment capability and walking flexibility of the SPMT vehicle.

[0042] Preferably, before step S2, the method further includes the following steps of prefabricating prestressed immersed tube segments:

[0043] The layout positions of the four rows of fixed piers are determined according to the layout positions of the SPMT vehicle, so that the four rows of fixed piers are staggered with the layout positions, and the fixed piers distributed transversely along the prestressed immersed tube segment are symmetrically arranged about the longitudinal center axis of the prestressed immersed tube segment; then the prestressed immersed tube segment is prefabricated, so that the two side walls and the two middle walls of the prestressed immersed tube segment are correspondingly arranged on the four rows of fixed piers.

[0044] It can ensure the force balance during the prefabrication of prestressed immersed tube sections and ensure better crack control effect of the prefabricated prestressed immersed tube sections.

[0045] Preferably, between steps S2 and S3, the vehicle group is divided into four zones along the transverse center axis and the longitudinal center axis of the prestressed immersed tube segment, and the hydraulic suspensions of all SPMT vehicles in each zone are connected in series through oil pipes; the four zones are connected in parallel through oil pipes;

[0046] In step S3, the train groups in the four zones synchronously lift the prestressed immersed tube segments in stages.

[0047] Four points of synchronous jacking are formed, and the trains in the four zones jack up the prestressed immersed tube sections synchronously and graded, ensuring that the force on the bottom plate when being jacked is uniform and layered, which can improve the crack control effect.

[0048] Preferably, between steps S3 and S4, the train set is divided into three zones, the train set below the front half of the prestressed immersed tube segment in the forward direction is regarded as one zone, and the train set below the rear half of the prestressed immersed tube segment in the forward direction is divided into two zones along the longitudinal center axis of the prestressed immersed tube segment; the hydraulic suspensions of all SPMT vehicles in each zone are connected in series through oil pipes, and the three zones are connected in parallel through oil pipes;

[0049] In step S4, the vehicle groups in the three zones support the prestressed immersed tube segments.

[0050] Three points of synchronous jacking are formed, and the train groups in the three zones support the prestressed immersed tube segments, ensuring that the three areas of the bottom plate are always located in the same plane when being jacked up, with uniform force, which can improve the crack control effect.

[0051] Preferably, before step S4, the semi-submersible barge is stern-to-side and moored to the dock by cables; then a 40mm-50mm thick steel plate is laid at the joint between the dock and the semi-submersible barge; and then the onboard support is arranged on the deck of the semi-submersible barge; wherein the lateral arrangement position of the onboard support on the semi-submersible barge is determined according to the arrangement position point of the SPMT vehicle.

[0052] After the semi-submersible barge is berthed and moored to the dock side by cables, 40mm-50mm thick steel plates are laid to meet the requirements of the SPMT vehicle for barge-on. Onboard supports are then arranged on the deck of the semi-submersible barge to ensure that the onboard supports will not interfere with the barge-on movement of the SPMT vehicle.

[0053] Preferably, 8 rows of shipboard supports are arranged at intervals laterally on the semi-submersible barge, of which 4 rows of shipboard supports correspond to the two side walls and two middle walls of the prestressed immersed tube segment, and the other 4 rows of shipboard supports are located between two adjacent rows of SPMT vehicles. The shipboard supports distributed laterally along the semi-submersible barge are symmetrically arranged about the longitudinal center axis of the prestressed immersed tube segment.

[0054] After the prestressed immersed tube segments are transferred from the dock to the semi-submersible barge, they are placed on 8 rows of ships for support. During the conversion process, the stress on the deck of the semi-submersible barge is uniform and smaller, reducing the deformation of the deck of the semi-submersible barge.

[0055] Preferably, in step S4, in a preselected operation window, the prestressed immersed tube segment is driven by the SPMT vehicle from the dock to the semi-submersible barge;

[0056] During the barge loading process, the barge loading speed is controlled within 0.5m / min to 1m / min, and the load is adjusted through the semi-submersible barge ballast tank to control the height difference between the dock surface and the stern deck surface and the buoyancy of the semi-submersible barge to meet the control requirements of the SPMT vehicle movement and the stability and safety of the semi-submersible barge.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] 1. The present invention provides a prestressed immersed tube segment. By arranging a transverse first prestressed steel bundle in the bottom plate of the prestressed immersed tube segment, all parts of the bottom plate can meet the support conditions of the SPMT vehicle, and then the SPMT vehicles can be fully distributed under the bottom plate, so that the prestressed immersed tube segment transported by the SPMT vehicle can provide sufficient support force and reduce the degree of cracking of the prestressed immersed tube segment, so that the SPMT vehicle can be used to transport the immersed tube segment; by arranging a transverse second prestressed steel bundle in the top plate, the second prestressed steel bundle can overcome the stress influence of the first prestressed steel bundle on the top plate, and the arrangement form (direction) of the first prestressed steel bundle and the second prestressed steel bundle conforms to the load form of the bottom plate and the top plate of the immersed tube segment during the operation period, meets the stress state of the immersed tube segment during the operation period, and can also reduce the reinforcement amount of the bottom plate and the top plate, thereby saving costs.

[0059] 2. The present invention provides a design method for a prestressed immersed tube segment, which can meet the requirements of the SPMT vehicle transporting the prestressed immersed tube segments and fully distributing them under the bottom plate, as well as the structural safety requirements of the prestressed immersed tube segments.

[0060] 3. The present invention provides a method for barging an SPMT vehicle, which can fully distribute the SPMT vehicle under the bottom plate by setting a transverse prestress on the bottom plate of the immersed tube segment; after determining the layout position of the SPMT vehicle, it can meet the support of the prestressed immersed tube segment and the bearing capacity during barging; and the transverse position of the SPMT vehicle at the prestressed immersed tube segment is staggered with the transverse position of the prestressed immersed tube segment corresponding to the fixed pier, so that after the prestressed immersed tube segment is prefabricated, the SPMT vehicle can be arranged under the prefabricated prestressed immersed tube segment, so as to realize the force conversion between the fixed pier and the SPMT vehicle; and the SPMT vehicle is staggered at the prestressed immersed tube segment. The lateral position of the immersed tube segment is staggered with the lateral position of the prestressed immersed tube segment corresponding to the support on the ship, so that the SPMT vehicle can transport the prestressed immersed tube segment from the dock to the semi-submersible barge without being disturbed by the support on the ship, and can thus convert the prestressed immersed tube segment from the sleeper support on the SPMT vehicle to the support on the ship, and the SPMT vehicle continues to unload force so that the top of the vehicle group does not contact the sleepers, allowing the SPMT vehicle to return to the dock, and then the SPMT vehicle is used to realize the overall barge process of the prestressed immersed tube segment. This process reduces the difficulty of controlling the cracking of the immersed tube segment during the barge process due to the large stroke adaptive adjustment capability and walking flexibility of the SPMT vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is the bending moment diagram of the sunken tube segment of the existing reinforced concrete sunken tube segment with multiple support systems;

[0062] Figure 2 The bending moment diagram of the existing reinforced concrete immersed tube segment during the operation period;

[0063] Figure 3 Schematic diagram of the prestressed immersed tube segment of the present invention Figure 1 ;

[0064] Figure 4 Schematic diagram of the prestressed immersed tube segment of the present invention Figure 2 ;

[0065] Figure 5 It is a schematic diagram of tensioning of a prestressed immersed tube segment of the present invention;

[0066] Figure 6 It is a schematic diagram of the arrangement of the first prestressed steel strand and the second prestressed steel strand of the prestressed immersed tube segment of the present invention;

[0067] Figure 7 This is a schematic diagram of the load form on the immersed tube segment during the operation period;

[0068] Figure 8 It is a schematic diagram of the structural form of the prestressed steel tendon;

[0069] Fig. 9 It is a schematic diagram of the structural form of the tensioning end;

[0070] Fig.10 A schematic diagram of supporting force control to facilitate crack control in immersed tube sections;

[0071] Fig.11 This is a schematic diagram of the arrangement of fixed piers during prefabrication;

[0072] Fig.12 It is a schematic diagram of the SPMT car and sleepers arranged under the floor after prefabrication;

[0073] Fig.13 Schematic diagram of the SPMT vehicle partition when the force on the fixed pier is converted into the force on the SPMT vehicle;

[0074] Fig.14 This is a schematic diagram of the load pattern on the immersed tube segment transported by the SPMT vehicle;

[0075] Fig.15 It is a schematic diagram of the longitudinal arrangement of the SPMT car and sleepers along the prestressed immersed tube segment;

[0076] Fig.16 Schematic diagram of the zones when the SPMT vehicle is transporting prestressed immersed tube segments;

[0077] Fig.17 It is a schematic diagram of the supporting force of the prestressed immersed tube segment under the support of the SPMT vehicle to meet the requirements of crack control;

[0078] Fig.18 It is a stress diagram of the prestressed immersed tube segment under the support of the SPMT vehicle to meet the requirements of crack control;

[0079] Figure 19-22 Schematic diagram of the process of transporting prestressed immersed tube segments into semi-submersible barges by SPMT vehicles;

[0080] Fig.23 This is a schematic diagram of the support arrangement on board;

[0081] Fig.24 A schematic diagram of fixing the prestressed immersed tube segment in a semi-submersible barge;

[0082] Fig.25 It is an equivalent immersed tube unit;

[0083] Fig.26 It is a simplified diagram of the calculation model;

[0084] Fig. 27 is a schematic diagram of the first bending moment diagram;

[0085] Fig.28 is a schematic diagram of the second bending moment diagram;

[0086] Fig.29is a schematic diagram of the cross section of the prestressed steel tendon;

[0087] Fig.30 It is a schematic diagram of the finite element model of the immersed tube segment SPMT vehicle transportation;

[0088] Fig.31 It is a stress diagram for analyzing whether the stress on the immersed tube segment meets the crack control requirements.

[0089] Markings in the figure: 1. immersed tube segment; 11. top plate; 12. bottom plate; 13. first side wall; 14. first middle wall; 15. second middle wall; 16. second side wall; 21. first prestressed steel strand; 211. first passing point; 212. second passing point; 213. third passing point; 214. fourth passing point; 215. fifth passing point; 22. second prestressed steel strand; 221. sixth passing point; 222. seventh passing point; 223. eighth passing point; 224. ninth passing point; 225. tenth passing point; 23. tensioning end; 31. fixed pier; 32. auxiliary pier; 4. SPMT vehicle; 41. sleeper; 5. semi-submersible barge; 51. shipboard support; 6. wharf; 52. bottom steel support. DETAILED DESCRIPTION

[0090] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0091] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0092] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0093] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0094] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0095] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0096] Example 1

[0097] In the prior art, such as Figure 1-Figure 7 As shown, the immersed tube segment 1 is moved by the SPMT vehicle 4 and transported by the semi-submersible barge 5. The immersed tube segment 1 is in a multi-support force system (supported by the prefabricated fixed pier 31, supported by the transported SPMT vehicle 4, and then supported by the ship support 51 transported by the semi-submersible barge 5), which is quite different from the traditional dry dock water filling and floating transportation, and also quite different from the designed force form, such as Figure 2 As shown in the figure, the design mainly considers the bending moment of immersed tube segment 1 during operation. Figure 1As shown, the bending moment distribution of the sunken tube segment 1 in the multi-support system is different from that of the sunken tube segment 1 in the operation period, so that when the SPMT vehicle 4 is used to move the sunken tube segment 1, it is impossible to fully cover the bottom of the sunken tube segment 1, and thus the bearing capacity provided by the SPMT vehicle 4 for moving the sunken tube segment 1 cannot be met.

[0098] In response to the above problems, Figure 3 As shown, this embodiment provides a prestressed immersed tube segment 1, comprising a top plate 11, a bottom plate 12, a first side wall 13, a first middle wall 14, a second middle wall 15 and a second side wall 16, wherein the first side wall 13, the first middle wall 14, the second middle wall 15 and the second side wall 16 are sequentially arranged along the transverse direction of the immersed tube segment, and are characterized in that they comprise a first prestressed steel strand 21 and a second prestressed steel strand 22;

[0099] The first prestressed steel strands 21 are arranged in the bottom plate 12, the first prestressed steel strands 21 are arranged transversely along the bottom plate 12, and the first prestressed steel strands 21 are spaced apart longitudinally along the bottom plate 12;

[0100] The first prestressed steel strand 21 includes a first passing point 211, a second passing point 212, a third passing point 213, a fourth passing point 214 and a fifth passing point 215. The first passing point 211 is located below the first side wall 13, the second passing point 212 is located between the first side wall 13 and the first middle wall 14, the third passing point 213 is located between the first middle wall 14 and the second middle wall 15, the fourth passing point 214 is located between the second middle wall 15 and the second side wall 16, and the fifth passing point 215 is located below the second side wall 16. The first prestressed steel strand 21 is vertically arranged in a wave shape, the first passing point 211, the third passing point 213 and the fifth passing point 215 are troughs, and the second passing point 212 and the fourth passing point 214 are crests.

[0101] The second prestressed steel strands 22 are arranged in the top plate 11, the second prestressed steel strands 22 are arranged transversely along the top plate 11, and the second prestressed steel strands 22 are spaced apart longitudinally along the top plate 11;

[0102] The second prestressed steel strand 22 includes a sixth passing point 221, a seventh passing point 222, an eighth passing point 223, a ninth passing point 224 and a tenth passing point 225. The sixth passing point 221 is located above the first side wall 13, the seventh passing point 222 is located between the first side wall 13 and the first middle wall 14, the eighth passing point 223 is located between the first middle wall 14 and the second middle wall 15, the ninth passing point 224 is located between the second middle wall 15 and the second side wall 16, and the tenth passing point 225 is located above the second side wall 16. The second prestressed steel strand 22 is arranged in a wave shape in the vertical direction. The sixth passing point 221, the eighth passing point 223 and the tenth passing point 225 are located at the crest, and the seventh passing point 222 and the ninth passing point 224 are located at the trough.

[0103] A transverse first prestressed steel strand 21 is arranged in the bottom plate 12 of the prestressed immersed tube segment 1 and is longitudinally spaced and distributed along the prestressed immersed tube segment 1 to meet the longitudinal support condition, and the transverse first prestressed steel strand 21 has a first passing point corresponding to the first side wall 13, a second passing point 212 corresponding to between the first side wall 13 and the first middle wall 14, a third passing point 213 corresponding to between the first middle wall 14 and the second middle wall 15, a fourth passing point 214 corresponding to between the second middle wall 15 and the second side wall 16, and a fifth passing point 215 corresponding to the second side wall 16, and the first prestressed steel strand 21 is arranged in a wave shape in the vertical direction, the first passing point 211, the third passing point 213 and the fifth passing point 215 are troughs, and the second passing point 212 and the fourth passing point 214 are troughs. The point 214 is a wave crest, so that the bottom plate 12 of the immersed tube segment 1 is greatly reinforced between the first side wall 13 and the first middle wall 14 and between the second middle wall 15 and the second side wall 16, and the bottom plate 12 of the immersed tube segment 1 is relatively strong between the first side wall 13, the first middle wall 14, the second middle wall 15 and the second side wall 16, so that all parts of the bottom plate 12 can meet the support conditions of the SPMT vehicle 4, and the SPMT vehicle 4 can be fully distributed under the bottom plate 12, so that the use of the SPMT vehicle 4 to transport the prestressed immersed tube segment 1 can provide sufficient support force, and can ensure that the strength of the bottom of the bottom plate 12 is close to equilibrium, thereby reducing the degree of cracking of the prestressed immersed tube segment 1, and then the SPMT vehicle 4 can be used to transport the immersed tube segment 1. In addition, the first transverse prestressed steel strand 21 is arranged on the bottom plate 12, which can also reduce the reinforcement amount of the bottom plate 12 to a certain extent, saving certain costs.

[0104] However, the setting of the first prestressed steel strand will cause the middle wall position corresponding to the top plate to arch upward, such as Figure 3 As shown in Figure 2, this arrangement will affect the stress of the top plate. By setting a second transverse prestressed steel strand in the top plate, as shown in Figure 2, Figure 4 As shown, the second prestressed steel strand can overcome the force effect of the first prestressed steel strand on the top plate, and as shown Figure 7 and Figure 2 In comparison, the arrangement of the first prestressed steel strands and the second prestressed steel strands conforms to the load form of the bottom plate and top plate of the immersed tube segment during the operation period, meets the stress state of the immersed tube segment during the operation period, and can also reduce the amount of reinforcement of the bottom plate and top plate, saving costs.

[0105] like Figure 8 and Fig. 9 As shown, tensioning ends 23 are provided at both ends of the first prestressed steel strand 21 and the second prestressed steel strand 22, which can tension the first prestressed steel strand 21 and the second prestressed steel strand 22 to provide sufficient prestress. Figure 4As shown, the first and fifth passing points are arranged at the vertical center of the bottom plate, and the sixth and tenth passing points are arranged at the vertical center of the top plate, which is convenient for tensioning. The first prestressed steel strand and the second prestressed steel strand are both smooth curves to improve the quality of prestressing. The first prestressed steel strand 21 and the second prestressed steel strand 22 can also be made of steel strands, such as Figure 8 shown.

[0106] Among them, the first prestressed steel bundle and the second prestressed steel bundle are arranged symmetrically in the transverse direction of the immersed tube section, which can better adapt to the transverse balanced layout of the immersed tube joint. The prestressed steel bundle is designed symmetrically, such as the first prestressed steel bundle, that is, the first passing point and the fifth passing point, the second passing point and the fourth passing point are arranged symmetrically. The first passing point and the fifth passing point are arranged at the center of the bottom plate (appropriate adjustments can be made), which is conducive to the operation of prestressed tensioning construction. The second passing point, the third passing point, and the fourth passing point are arranged as close to the bottom plate or the lower surface as possible when meeting the structural requirements of the prestressed pipeline and the thickness of the steel bar protective layer. The prestressed steel bundle is designed as a smooth curve through 5 passing points.

[0107] Furthermore, the distances between the second and fourth passing points and the top surface of the bottom plate are both greater than or equal to the thickness of the steel bar protective layer on the top surface of the bottom plate, the distance between the third passing point and the bottom surface of the bottom plate is greater than or equal to the thickness of the steel bar protective layer on the bottom surface of the bottom plate, the distance between the seventh and ninth passing points and the bottom surface of the top plate is greater than or equal to the thickness of the steel bar protective layer on the bottom surface of the top plate, and the distance between the eighth passing point and the top surface of the top plate is greater than or equal to the thickness of the steel bar protective layer on the top surface of the top plate, so as to ensure the safety of the structural force. Among them, the distances between the second and fourth passing points and the top surface of the bottom plate are both equal to the thickness of the steel bar protective layer on the top surface of the bottom plate, the distance between the third passing point and the bottom surface of the bottom plate is equal to the thickness of the steel bar protective layer on the bottom surface of the bottom plate, the distance between the seventh and ninth passing points and the bottom surface of the top plate is equal to the thickness of the steel bar protective layer on the bottom surface of the top plate, and the distance between the eighth passing point and the top surface of the top plate is equal to the thickness of the steel bar protective layer on the top surface of the top plate, so as to set the prestress to the maximum extent and reduce the setting of reinforcement.

[0108] This embodiment not only considers the full coverage design of the SPMT vehicle 4, but also considers the stress characteristics of the immersed tube tunnel during operation. The prestressed steel strands can meet the stress requirements of the immersed tube segment 1 during operation, and can resist the load of the SPMT vehicle 4. This design can prevent the immersed tube segment 1 from cracking and can greatly reduce the reinforcement of reinforced concrete.

[0109] Example 2

[0110] This embodiment provides a design method for a prestressed immersed tube segment 1, which is used to design the prestressed immersed tube segment 1 in Embodiment 1, and includes the following steps:

[0111] S01: Determine the preset position range of the onboard support 51 on the semi-submersible barge 5 for supporting the prestressed immersed tube segment 1 and the fixed pier 31 when the prestressed immersed tube segment 1 is prefabricated, and exclude the lateral position of the prestressed immersed tube segment 1 when the SPMT vehicle 4 transports the prestressed immersed tube segment 1 according to the preset position range of the onboard support 51 and the fixed pier 31; then determine the number of required SPMT vehicles 4 according to the weight of the prestressed immersed tube segment 1; then obtain all the layout position points of the required SPMT vehicles 4 corresponding to the prestressed immersed tube segment 1 according to the number of required SPMT vehicles 4, excluding the lateral position of the SPMT vehicle 4 when transporting the prestressed immersed tube segment 1, and the layout requirements; in step S01, the layout requirements are: arrange the SPMT vehicles 4 in a row below the prestressed immersed tube segment 1, and arrange the SPMT vehicles 4 symmetrically in the transverse direction of the prestressed immersed tube segment 1;

[0112] S02: Determine the cross-sectional design of the first prestressed steel strand and the second prestressed steel strand according to the layout position of the SPMT vehicle and the longitudinal setting position of the prestressed immersed tube segment, and the design of the prestressed immersed tube segment is completed.

[0113] Optionally, step S02 includes the following steps:

[0114] S02.1: If Fig.25 As shown, an equivalent immersed tube unit with a longitudinal length of the unit is obtained, and the bottom plate, top plate, middle wall and side wall of the equivalent immersed tube unit are all equivalent to beam units, and the beam units are rigidly connected;

[0115] S02.2: Determine the position where the support force is applied at the bottom of the equivalent immersed tube unit according to the layout position of the SPMT vehicle, simulate the support of the SPMT vehicle on the equivalent immersed tube unit, and establish a simplified calculation model of the equivalent immersed tube unit, such as Fig.26 As shown;

[0116] S02.3: Analyze the force form of the simplified calculation model under the combined action of the support force and the equivalent immersed tube unit gravity, and obtain the first bending moment diagram, such as Fig. 27 As shown;

[0117] S02.4: A first prestressed steel strand and a second prestressed steel strand of a prestressed immersed tube segment as claimed in any one of claims 1 to 2 are added to the bottom plate and the top plate of the equivalent immersed tube unit respectively;

[0118] S02.5: Then change the cross-sectional area of ​​the first prestressed steel strand and the second prestressed steel strand, and analyze the force form of the simplified calculation model under the combined action of the support force, the prestress provided by the first prestressed steel strand, the prestress provided by the second prestressed steel strand, and the gravity of the equivalent immersed tube unit to obtain the second bending moment diagram, such as Fig.28 As shown;

[0119] S02.6: Determine the bending moments of the bottom plate and top plate of the equivalent immersed tube unit. If the bending moments of the bottom plate in the second bending moment diagram except for the connection between the bottom plate and the side wall are not greater than the preset bending moment, and the bending moment of the top plate in the second bending moment diagram is not greater than the bending moment of the top plate in the first bending moment diagram, then the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand meet the force requirements of the equivalent immersed tube unit, and obtain the relationship between the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand and the unit length, and enter S02.7. Otherwise, repeat steps S02.5 and S02.6 until entering S02.7;

[0120] S02.7: Select the number of steel strands and the longitudinal spacing of the first prestressed steel tendons and the second prestressed steel tendons based on the relationship between the cross-sectional area and the unit length of the first prestressed steel tendons and the second prestressed steel tendons that meet the requirements;

[0121] S02.8: According to the number of steel strands and longitudinal spacing of the selected first and second prestressed steel strands, establish the finite element model of the prestressed immersed tube segment SPMT vehicle transportation, such as Fig.30 As shown;

[0122] S02.9: If Fig.31 As shown, it is analyzed whether the stress of the prestressed immersed tube segment meets the crack control requirements. If it does, the prestressing design is completed, and the cross-sectional design of the first prestressed steel bundle and the second prestressed steel bundle as well as the longitudinal setting position of the prestressed immersed tube segment are determined; if it does not meet the requirements, the number of steel strands of the load bundle or the longitudinal arrangement spacing is readjusted, and steps S02.8 and S02.9 are repeated until the stress of the immersed tube segment meets the crack control requirements, the prestressing design is completed, and the cross-sectional design of the first prestressed steel bundle and the second prestressed steel bundle as well as the longitudinal setting position of the prestressed immersed tube segment are obtained.

[0123] The above method can adjust the number of steel strands and the longitudinal arrangement spacing of the first prestressed steel bundle and the second prestressed steel bundle by obtaining the relationship between the cross-sectional area and the unit length of the first prestressed steel bundle and the second prestressed steel bundle that meet the requirements, so as to obtain the cross-sectional design of the first prestressed steel bundle and the second prestressed steel bundle that better meet the requirements and the longitudinal setting position of the prestressed immersed tube segment.

[0124] With respect to S02.1-S02.9 above, this embodiment provides a specific design case, taking a unit length of 1m as an example:

[0125] (1) Simplified calculation model for prestressed design

[0126] Take a 1m long immersed tube segment, and make the bottom plate, top plate, middle wall and side wall of the 1m long immersed tube segment equivalent to beam units. For example, if the bottom plate is 1.65m high, then the bottom plate is equivalent to a beam unit with a cross-section of 1.65m×1m. The beam units are connected by rigid connections to form equivalent immersed tube units. Fig.25 As shown in Figure 2, a simplified calculation model is established based on the equivalent immersed tube unit, as shown in Figure 2. Fig.26 shown.

[0127] The supporting force is applied according to the position of the SPMT vehicle. The weight of a 1m immersed tube section is G. If n rows of SPMT vehicles are arranged, the supporting force of the SPMT vehicles is G / n.

[0128] (2) Analyze the stress form of the simplified calculation model under the support and gravity of the SPMT vehicle. The first bending moment diagram is as follows: Fig. 27 shown.

[0129] (3) Transverse prestressing force (first prestressing steel strand and second prestressing steel strand) is added to the bottom plate and the top, and the prestressing form conforms to the relevant settings (structural form) in Example 1. The cross-sectional area of ​​the prestressing steel strand is changed, and the force form of the simplified calculation model under the combined action of the SPMT vehicle support, prestressing force, and gravity is analyzed to obtain the second bending moment diagram, as shown in FIG. Fig.28 As shown. Until the following two requirements are met: ① The bottom plate bending moment is as close to zero as possible (except for the connection between the bottom plate and the side wall), and the bottom plate bending moment can be small, such as lower than the preset bending moment. ② The top plate bending moment is not greater than the bending moment when the SPMT car is supported and gravity acts, that is, it is not greater than the bending moment of the top plate in the first bending moment diagram.

[0130] (4) According to the calculated cross-sectional area, adjust the number of prestressed steel strands or the longitudinal layout method to carry out prestressing design. For example, the calculated prestressed cross-sectional areas of the bottom plate and top plate are 2400mm 2 、1200mm 2 , the cross-sectional area of ​​a single strand is 140mm 2 , a prestressed steel strand consisting of 17 steel strands can be used with a cross-sectional area of ​​2380mm 2 The longitudinal spacing of the prestressed steel strands in the bottom and top plates is 1m and 2m respectively. The number of prestressed steel strands determines its cross-sectional area. Fig.29 shown.

[0131] (5) According to the designed prestressed steel strands, the finite element model of the immersed tube segment SPMT vehicle transportation is established, such as Fig.30 As shown in the figure, analyze whether the stress of the immersed tube segment meets the crack control requirements, such as Fig.31 If the requirements are met, the prestressing design is completed. If not, the number of steel strands or the longitudinal arrangement spacing is readjusted until the stress on the immersed tube section meets the crack control requirements and the prestressing design is completed.

[0132] Advantages of the prestressed immersed tube segment obtained after the above design:

[0133] (1) It can meet the requirements for crack control of immersed tube segments during transportation by SPMT vehicles.

[0134] (2) Considering that the load form on the bottom plate of the immersed tube segment during operation is the same as the load form when supported by the SPMT vehicle (similar to the uniformly distributed load), adding prestress in the top plate and bottom plate is beneficial to the stress safety of the immersed tube segment during operation.

[0135] Example 3

[0136] This embodiment provides a method for loading a SPMT vehicle 4, which is used for loading a prestressed immersed tube segment 1 described in Embodiment 1, and includes the following steps:

[0137] S1, determine the preset position range of the onboard support 51 on the semi-submersible barge 5 for supporting the prestressed immersed tube segment 1 and the fixed pier 31 when the prestressed immersed tube segment 1 is prefabricated, and exclude the lateral position of the prestressed immersed tube segment 1 when the SPMT vehicle 4 transports the prestressed immersed tube segment 1 according to the preset position range of the onboard support 51 and the fixed pier 31; then determine the number of required SPMT vehicles 4 according to the weight of the prestressed immersed tube segment 1; then obtain all the layout position points of the required SPMT vehicles 4 corresponding to the prestressed immersed tube segment 1 according to the number of required SPMT vehicles 4, excluding the lateral position of the SPMT vehicle 4 when transporting the prestressed immersed tube segment 1, and the layout requirements; in step S1, the layout requirements are: arrange the SPMT vehicles 4 in a row below the prestressed immersed tube segment 1, and arrange the SPMT vehicles 4 symmetrically in the transverse direction of the prestressed immersed tube segment 1;

[0138] Before step S2, the method further includes the following steps of prefabricating the prestressed immersed tube segment 1:

[0139] The arrangement positions of the four rows of fixed piers 31 are determined according to the arrangement positions of the SPMT vehicle 4, so that the four rows of fixed piers 31 are staggered with the arrangement positions, and the fixed piers 31 distributed transversely along the prestressed immersed tube segment 1 are symmetrically arranged about the longitudinal center axis of the prestressed immersed tube segment 1; then the prestressed immersed tube segment 1 is prefabricated so that the two side walls and the two middle walls of the prestressed immersed tube segment 1 are correspondingly arranged on the four rows of fixed piers 31, as shown in FIG. Fig.11 It can ensure the force balance during the prefabrication of the prestressed immersed tube segment 1 and ensure a better crack control effect of the prefabricated prestressed immersed tube segment 1.

[0140] Optionally, auxiliary buttresses 32 may be provided between the four rows of fixed buttresses 31, such as Fig.10As shown, the auxiliary pier 32 also needs to be offset from the layout position of the SPMT vehicle 4. The auxiliary pier 32 cannot be used as the main supporting area. The purpose of the auxiliary pier 32 is to ensure that the bottom plate 12 surface tends to be horizontal. The supporting force should be set relatively small, which is conducive to the support force control of the immersed tube segment 1 to control cracking.

[0141] After the immersed tube segment 1 is prefabricated, it is placed on the fixed piers 31. The arrangement of the fixed piers 31 needs to take into account the support and travel requirements of the SPMT vehicle 4. The fixed piers 31 are arranged at the side walls and the middle wall, and are evenly arranged along the longitudinal direction of the immersed tube segment 1, with one pier arranged every 2 meters.

[0142] The SPMT vehicle 4 moves to the bottom of the pipe segment, and the SPMT vehicle 4 is arranged along the longitudinal direction of the immersed pipe segment 1, and the vehicle group is arranged symmetrically along the transverse direction of the immersed pipe segment 1. The SPMT vehicle 4 group must meet the load-bearing requirements of the immersed pipe segment 1. The SPMT vehicle 4 needs to avoid the fixed pier 31 and the ship support 51 to ensure a smooth walking track of the SPMT vehicle 4.

[0143] For example, if the immersed tube section 1 weighs 34,000 tons, the SPMT vehicle 4 needs 1020 axles, 15 rows, 60 axles in each row, and a load capacity of about 40,000 tons, which is greater than the total weight of the immersed tube section 1 and meets the load requirement.

[0144] S2, according to the layout position of the SPMT car 4, the SPMT car 4 is arranged at the bottom of the prestressed immersed tube segment 1, and each row of the SPMT cars 4 forms a train set, and sleepers 41 are arranged on the train set, such as Fig.12 As shown; the sleepers 41 are arranged at equal intervals in the longitudinal direction of the immersed tube section 1, one every 2m.

[0145] S3, lift up the prestressed immersed tube segment 1 by the SPMT vehicle 4, so that the prestressed immersed tube segment 1 is separated from the fixed pier 31, as shown in FIG. Fig.14 and Fig.15 As shown;

[0146] Optionally, between steps S2 and S3, the train set is divided into four zones along the transverse center axis and the longitudinal center axis of the prestressed immersed tube segment 1, such as Fig.13 As shown, the hydraulic suspensions of all SPMT vehicles 4 in each zone are connected in series through oil pipes; the four zones are connected in parallel through oil pipes;

[0147] In step S3, the vehicle groups in the four zones synchronously and gradedly lift the prestressed immersed tube segment 1. A four-point synchronous lifting is formed, and the vehicle groups in the four zones synchronously and gradedly lift the prestressed immersed tube segment 1, ensuring that the force on the bottom plate 12 is uniform and hierarchical when being lifted, which can improve the crack control effect. Specifically, the SPMT vehicle 4 is lifted, and the immersed tube segment 1 is converted from the support of the fixed pier 31 to the support of the SPMT vehicle 4. During the lifting process, a four-zone graded synchronous lifting is adopted, that is, the SPMT vehicle 4 groups are divided into four zones, and the hydraulic suspension in each zone is connected in series through the oil pipe, and the direct oil circuits between zones are connected in parallel, thereby forming an adaptive four-point support.

[0148] Before step S4, the semi-submersible barge 5 is stern-to-side and moored to the side of the wharf 6 by cables; then a 40mm-50mm thick steel plate is laid at the joint between the wharf 6 and the semi-submersible barge 5; and then a shipboard support 51 is arranged on the deck of the semi-submersible barge 5; wherein the lateral arrangement position of the shipboard support 51 on the semi-submersible barge 5 is determined according to the arrangement position point of the SPMT vehicle 4. After the semi-submersible barge 5 is stern-to-side and moored to the side of the wharf 6 by cables, a 40mm-50mm thick steel plate is laid to meet the requirements of the SPMT vehicle 4 for barge-on, and then the shipboard support 51 is arranged on the deck of the semi-submersible barge 5, and the error in the mooring position of the semi-submersible barge 5 can be avoided, which causes the shipboard support 51 and the SPMT vehicle 4 to be misaligned, and it can be ensured that the shipboard support 51 does not interfere with the barge-on movement of the SPMT vehicle 4.

[0149] Further, such as Fig.23 As shown, 8 rows of ship supports 51 are arranged at intervals on the semi-submersible barge 5, of which 4 rows of ship supports 51 correspond to the two side walls and two middle walls of the prestressed immersed tube segment 1, and the other 4 rows of ship supports 51 are located between two adjacent rows of SPMT vehicles 4. The ship supports 51 distributed laterally along the semi-submersible barge 5 are symmetrically arranged about the longitudinal center axis of the prestressed immersed tube segment 1. After the prestressed immersed tube segment 1 is transferred from the dock 6 to the semi-submersible barge 5, it is placed on the 8 rows of ship supports 51. During the conversion process, the deck of the semi-submersible barge 5 is subjected to uniform and smaller stress, reducing the deformation of the deck of the semi-submersible barge 5. The ship supports 51 are arranged at equal intervals in the longitudinal direction, with one arranged every 2m.

[0150] S4, use the SPMT vehicle to drive the prestressed immersed tube segment from the prefabrication plant to the semi-submersible barge via the dock; Figure 17-Figure 18 As shown, under the support of the SPMT vehicle 4, the force on the immersed tube segment 1 meets the requirements of crack control.

[0151] Optionally, between steps S3 and S4, the vehicle group is divided into three zones, such as Fig.16As shown, the vehicle group below the front half of the prestressed immersed tube segment 1 in the forward direction is regarded as one zone, and the vehicle group below the rear half of the prestressed immersed tube segment 1 in the forward direction is divided into two zones along the longitudinal center axis of the prestressed immersed tube segment 1; the hydraulic suspensions of all SPMT vehicles 4 in each zone are connected in series through oil pipes, and the three zones are connected in parallel through oil pipes;

[0152] In step S4, the vehicle groups in the three zones support the prestressed immersed tube segment 1. A three-point synchronous lifting is formed, and the vehicle groups in the three zones support the prestressed immersed tube segment 1, ensuring that the three zones of the bottom plate 12 are always located in the same plane when being lifted, and the force is evenly applied, which can improve the crack control effect.

[0153] In step S4, Figure 19-22 As shown, in the pre-selected operation window, the prestressed immersed tube segment 1 is driven by the SPMT vehicle 4 to be barged from the dock 6 to the semi-submersible barge 5; through theoretical analysis, a suitable operation window (with small wind and waves and appropriate tidal changes) is selected as the pre-selected operation window;

[0154] During the process of loading, the loading speed is controlled within 0.5m / min to 1m / min, and the load is adjusted through the ballast tank of the semi-submersible barge 5, and the height difference between the dock 6 and the stern deck surface and the floating state of the semi-submersible barge 5 are controlled to meet the control requirements of the SPMT vehicle 4 walking and the stability and safety of the semi-submersible barge 5. The floating state of the semi-submersible barge 5 includes heel and pitch. Specifically, the height difference between the dock 6 and the stern deck surface of the semi-submersible barge 5 is controlled within ±5cm, and the heel and pitch of the semi-submersible barge 5 are controlled within 1°.

[0155] S5. The SPMT vehicle supports the hydraulic cylinder to lower the prestressed immersed tube segment until it falls on the support on the ship;

[0156] S6, the SPMT car support hydraulic cylinder continues to descend so that the sleepers do not touch the submerged tube section;

[0157] S7. The SPMT vehicle was returned to the wharf and the loading of the prestressed immersed tube section was completed.

[0158] The sleepers 41 are provided to prevent the SPMT vehicle 4 from directly contacting the prestressed immersed tube segment 1 , thereby preventing a large cracking process caused by direct contact between the steel structure SPMT vehicle 4 and the concrete of the prestressed immersed tube segment 1 .

[0159] like Fig.24 As shown, after the pipe segment is put on the barge, the semi-submersible barge 5 is sealed and reinforced for the immersed pipe segment 1. The sealing and reinforcement uses the bottom steel bracket 52 as the main limit device, supplemented by steel wire ropes. After the immersed pipe segment 1 is in place, the forklift places the bottom steel bracket 52 at the designated position, welds and reinforces it, and the steel wire rope uses a basket screw to further tighten the immersed pipe segment 1.

[0160] The method for barging the SPMT vehicle 4 described in this embodiment greatly expands the supportable area and reduces the control requirements for the supporting force by setting a transverse prestress on the bottom plate 12 of the immersed tube segment 1, so that the SPMT vehicle 4 can be fully arranged under the bottom plate 12; after determining the arrangement position of the SPMT vehicle 4, it can meet the support of the prestressed immersed tube segment 1 and the bearing capacity during barging; and the transverse position of the SPMT vehicle 4 at the prestressed immersed tube segment 1 is staggered with the transverse position of the prestressed immersed tube segment 1 corresponding to the fixed pier 31, so that after the prestressed immersed tube segment 1 is prefabricated, the SPMT vehicle 4 can be arranged under the prefabricated prestressed immersed tube segment 1, so as to realize the force conversion between the fixed pier 31 and the SPMT vehicle 4; and The lateral position of the prestressed immersed tube segment 1 by the MT vehicle 4 is staggered with the lateral position of the prestressed immersed tube segment 1 corresponding to the support 51 on the ship, so that the SPMT vehicle 4 can transport the prestressed immersed tube segment 1 from the dock 6 to the semi-submersible barge 5 without being disturbed by the support 51 on the ship, and thus can convert the prestressed immersed tube segment 1 from the support of the sleepers 41 on the SPMT vehicle 4 to the support 51 on the ship, and the SPMT vehicle 4 continues to unload the force, so that the top of the vehicle group does not contact the immersed tube segment, so that the SPMT vehicle 4 can be returned to the dock 6, and then the SPMT vehicle 4 is used to realize the overall barge process of the prestressed immersed tube segment 1. In this process, due to the large stroke adaptive adjustment capability and walking flexibility of the SPMT vehicle 4, the difficulty of controlling the cracking of the immersed tube segment 1 during the barge process is reduced.

[0161] The present invention greatly expands the support area and reduces the control requirements for the supporting force by setting transverse prestress on the bottom plate 12 of the immersed tube segment 1, so that the SPMT vehicle 4 can be fully distributed under the bottom plate 12, and then the SPMT vehicle 4 is used to realize the overall barge process of the prestressed immersed tube segment 1. In this process, the difficulty of controlling the cracking of the immersed tube segment 1 during the barge process is reduced due to the large stroke adaptive adjustment capability and walking flexibility of the SPMT vehicle 4.

[0162] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A prestressed immersed tube joint, comprising a top plate, a bottom plate, a first side wall, a first middle wall, a second middle wall and a second side wall, wherein the first side wall, the first middle wall, the second middle wall and the second side wall are sequentially arranged along the transverse direction of the immersed tube joint, characterized in that: including a first prestressed steel tendon and a second prestressed steel tendon; The first prestressed steel strands are arranged in the bottom plate, the first prestressed steel strands are arranged transversely along the bottom plate, and the first prestressed steel strands are distributed at intervals longitudinally along the bottom plate; The first prestressed steel strand includes a first passing point, a second passing point, a third passing point, a fourth passing point and a fifth passing point, the first passing point is located below the first side wall, the second passing point is located between the first side wall and the first middle wall, the third passing point is located between the first middle wall and the second middle wall, the fourth passing point is located between the second middle wall and the second side wall, and the fifth passing point is located below the second side wall, the first prestressed steel strand is vertically arranged in a wave shape, the first passing point, the third passing point and the fifth passing point are wave troughs, and the second passing point and the fourth passing point are wave crests; The second prestressed steel strands are arranged in the top plate, the second prestressed steel strands are arranged transversely along the top plate, and the second prestressed steel strands are distributed at intervals longitudinally along the top plate; The second prestressed steel bundle includes a sixth passing point, a seventh passing point, an eighth passing point, a ninth passing point and a tenth passing point. The sixth passing point is located above the first side wall, the seventh passing point is located between the first side wall and the first middle wall, the eighth passing point is located between the first middle wall and the second middle wall, the ninth passing point is located between the second middle wall and the second side wall, and the tenth passing point is located above the second side wall. The second prestressed steel bundle is arranged in a wave shape in the vertical direction. The sixth passing point, the eighth passing point and the tenth passing point are located at the crest of the wave, and the seventh passing point and the ninth passing point are located at the trough of the wave.

2. A prestressed immersed tube segment according to claim 1, characterized in that: The first passing point and the fifth passing point are both arranged at the vertical center of the bottom plate, and the sixth passing point and the tenth passing point are both arranged at the vertical center of the top plate; And / or, the distances between the second and fourth passing points and the top surface of the bottom plate are both greater than or equal to the thickness of the steel bar protective layer on the top surface of the bottom plate, the distance between the third passing point and the bottom surface of the bottom plate is greater than or equal to the thickness of the steel bar protective layer on the bottom surface of the bottom plate, the distances between the seventh and ninth passing points and the bottom surface of the top plate are greater than or equal to the thickness of the steel bar protective layer on the bottom surface of the top plate, and the distance between the eighth passing point and the top surface of the top plate is greater than or equal to the thickness of the steel bar protective layer on the top surface of the top plate; and / or, the first prestressed steel tendon and the second prestressed steel tendon are both smooth curves; And / or, the first prestressed steel strand and the second prestressed steel strand are arranged laterally symmetrically in the immersed tube segment.

3. A design method for a prestressed immersed tube segment, characterized in that: The method for designing the prestressed immersed tube segment according to any one of claims 1 to 2 comprises the following steps: S01: Determine the preset position range of the onboard support for supporting the prestressed immersed tube segment on the semi-submersible barge and the fixed piers during the prefabrication of the prestressed immersed tube segment, and exclude the lateral position of the prestressed immersed tube segment when the SPMT vehicle transports the prestressed immersed tube segment according to the preset position range of the onboard support and the fixed pier; then determine the number of required SPMT vehicles according to the weight of the prestressed immersed tube segment; then obtain all the layout position points of the required SPMT vehicles corresponding to the prestressed immersed tube segment according to the number of required SPMT vehicles, excluding the lateral position of the SPMT vehicle when transporting the prestressed immersed tube segment, and the layout requirements; in step S01, the layout requirements are: arrange the SPMT vehicles in a row below the prestressed immersed tube segment, and arrange the SPMT vehicles symmetrically in the transverse direction of the prestressed immersed tube segment; S02: According to the layout position of the SPMT vehicle, the cross-sectional design of the first prestressed steel strand and the longitudinal setting position of the prestressed immersed tube segment are determined, and the design of the prestressed immersed tube segment is completed.

4. The design method of the prestressed immersed tube segment according to claim 3 is characterized in that: Step S02 includes the following steps: S02.1: Obtain an equivalent immersed tube unit with the longitudinal direction as the unit length. The bottom plate, top plate, middle wall and side wall of the equivalent immersed tube unit are all equivalent to beam units, and the beam units are rigidly connected; S02.2: Determine the position where the support force is applied at the bottom of the equivalent immersed tube unit according to the layout position of the SPMT vehicle, simulate the support of the SPMT vehicle on the equivalent immersed tube unit, and establish a simplified calculation model of the equivalent immersed tube unit; S02.3: Analyze the force form of the simplified calculation model under the combined action of the support force and the gravity of the equivalent immersed tube unit, and obtain the first bending moment diagram; S02.4: A first prestressed steel strand and a second prestressed steel strand of a prestressed immersed tube segment as claimed in any one of claims 1 to 2 are added to the bottom plate and the top plate of the equivalent immersed tube unit respectively; S02.5: Then, the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand are changed, and the force form of the simplified calculation model under the combined action of the supporting force, the prestress provided by the first prestressed steel strand, the prestress provided by the second prestressed steel strand, and the gravity of the equivalent immersed tube unit is analyzed to obtain the second bending moment diagram; S02.6: Determine the bending moments of the bottom plate and top plate of the equivalent immersed tube unit. If the bending moments of the bottom plate in the second bending moment diagram except for the connection between the bottom plate and the side wall are not greater than the preset bending moment, and the bending moment of the top plate in the second bending moment diagram is not greater than the bending moment of the top plate in the first bending moment diagram, then the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand meet the force requirements of the equivalent immersed tube unit, and obtain the relationship between the cross-sectional areas of the first prestressed steel strand and the second prestressed steel strand and the unit length, and enter S02.

7. Otherwise, repeat steps S02.5 and S02.6 until entering S02.7; S02.7: Select the number of steel strands and the longitudinal spacing of the first prestressed steel tendons and the second prestressed steel tendons based on the relationship between the cross-sectional area and the unit length of the first prestressed steel tendons and the second prestressed steel tendons that meet the requirements; S02.8: Establish a finite element model for the transportation of prestressed immersed tube segments by SPMT vehicles based on the number of steel strands and longitudinal spacing of the selected first prestressed steel strands and the second prestressed steel strands; S02.9: Analyze whether the stress on the prestressed immersed tube segment meets the crack control requirements. If so, complete the prestressing design and determine the cross-sectional design of the first prestressed steel strand and the second prestressed steel strand as well as their longitudinal setting positions of the prestressed immersed tube segment. If not, readjust the number of steel strands in the load bundle or the longitudinal arrangement spacing and repeat steps S02.8 and S02.9 until the stress on the immersed tube segment meets the crack control requirements. Complete the prestressing design and obtain the cross-sectional design of the first prestressed steel strand and the second prestressed steel strand as well as their longitudinal setting positions of the prestressed immersed tube segment.

5. A method for loading a SPMT onto a vehicle, characterized in that: The method for barging the prestressed immersed tube segment according to any one of claims 1 to 2 comprises the following steps: S1, determine the preset position range of the onboard support on the semi-submersible barge for supporting the prestressed immersed tube segment and the fixed piers when the prestressed immersed tube segment is prefabricated, and exclude the lateral position of the prestressed immersed tube segment when the SPMT vehicle transports the prestressed immersed tube segment according to the preset position range of the onboard support and the fixed pier; then determine the number of required SPMT vehicles according to the weight of the prestressed immersed tube segment; then obtain all the layout position points of the required SPMT vehicles corresponding to the prestressed immersed tube segment according to the number of required SPMT vehicles, excluding the lateral position of the SPMT vehicle when transporting the prestressed immersed tube segment, and the layout requirements; in step S1, the layout requirements are: arrange the SPMT vehicles in a row below the prestressed immersed tube segment, and arrange the SPMT vehicles symmetrically in the transverse direction of the prestressed immersed tube segment; S2. Arranging the SPMT cars at the bottom of the prestressed immersed tube segment according to the arrangement positions of the SPMT cars, each row of the SPMT cars forms a train set, and sleepers are arranged on the train set; S3. Lift the prestressed immersed tube segment by the SPMT vehicle so that the prestressed immersed tube segment is separated from the fixed pier; S4, use the SPMT vehicle to drive the prestressed immersed tube segment from the prefabrication plant to the semi-submersible barge via the dock; S5. The SPMT vehicle supports the hydraulic cylinder to lower the prestressed immersed tube segment until it falls on the support on the ship; S6, the SPMT car support hydraulic cylinder continues to descend so that the sleepers do not touch the submerged tube section; S7. The SPMT vehicle was returned to the wharf and the loading of the prestressed immersed tube section was completed.

6. A method for loading a SPMT onto a vehicle according to claim 4, characterized in that: Before step S2, the method further includes the following steps of prefabricating prestressed immersed tube segments: The layout positions of the four rows of fixed piers are determined according to the layout positions of the SPMT vehicle, so that the four rows of fixed piers are staggered with the layout positions, and the fixed piers distributed transversely along the prestressed immersed tube segment are symmetrically arranged about the longitudinal center axis of the prestressed immersed tube segment; then the prestressed immersed tube segment is prefabricated, so that the two side walls and the two middle walls of the prestressed immersed tube segment are correspondingly arranged on the four rows of fixed piers.

7. A method for loading a SPMT onto a vehicle according to claim 4, characterized in that: Between steps S2 and S3, the vehicle group is divided into four zones along the transverse center axis and the longitudinal center axis of the prestressed immersed tube segment, and the hydraulic suspensions of all SPMT vehicles in each zone are connected in series through oil pipes; the four zones are connected in parallel through oil pipes; In step S3, the train groups in the four zones synchronously lift the prestressed immersed tube segments in stages; Between steps S3 and S4, the train set is divided into three zones, the train set below the front half of the prestressed immersed tube segment in the forward direction is regarded as one zone, and the train set below the rear half of the prestressed immersed tube segment in the forward direction is divided into two zones along the longitudinal center axis of the prestressed immersed tube segment; the hydraulic suspensions of all SPMT vehicles in each zone are connected in series through oil pipes, and the three zones are connected in parallel through oil pipes; In step S4, the vehicle groups in the three zones support the prestressed immersed tube segments.

8. A method for loading a SPMT onto a vehicle according to claim 4, characterized in that: Before step S4, the semi-submersible barge is stern-to-side and moored to the dock by cables; then a 40mm-50mm thick steel plate is laid at the joint between the dock and the semi-submersible barge; and then the onboard support is arranged on the deck of the semi-submersible barge; wherein the lateral arrangement position of the onboard support on the semi-submersible barge is determined according to the arrangement position point of the SPMT vehicle.

9. A method for loading a SPMT onto a vehicle according to claim 8, characterized in that: Eight rows of shipboard supports are arranged at intervals laterally on the semi-submersible barge, of which four rows of shipboard supports correspond to the two side walls and two middle walls of the prestressed immersed tube segment, and the other four rows of shipboard supports are located between two adjacent rows of SPMT vehicles. The shipboard supports distributed laterally along the semi-submersible barge are symmetrically arranged about the longitudinal center axis of the prestressed immersed tube segment.

10. A method for loading a SPMT onto a vehicle according to any one of claims 4 to 9, characterized in that: In step S4, in the preselected operation window, the prestressed immersed tube segment is driven by the SPMT vehicle from the dock to the semi-submersible barge; During the barge loading process, the barge loading speed is controlled within 0.5m / min to 1m / min, and the load is adjusted through the semi-submersible barge ballast tank to control the height difference between the dock surface and the stern deck surface and the buoyancy of the semi-submersible barge to meet the control requirements of the SPMT vehicle movement and the stability and safety of the semi-submersible barge.

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