Steel box girder sliding device and steel box girder pushing method

Abstract

The invention relates to the technical field of viaduct construction, in particular to a steel box girder sliding device and a steel box girder pushing method.The steel box girder sliding device comprises sliding shoes used for supporting a steel box girder and installed on sliding rails in the working state; the counter-force seat is mounted on the sliding track in a working state; the two ends of the hydraulic jack are hinged to the corresponding sliding shoes and the counter-force base respectively; one end of the balance weight connecting frame is hinged to the sliding shoe, and the balance weight connecting frame can slide in the advancing direction of the sliding shoe relative to the counter-force base; the counterweight assembly is hinged with the other end of the counterweight connecting frame; wherein in the moving process of the sliding shoe, the middle of the balance weight connecting frame is downwards pressed on the counter-force base, the balance weight assembly and the sliding rail are arranged in a spaced mode, in the moving process of the counter-force base, the balance weight assembly is downwards pressed on the sliding rail, the balance weight connecting frame and the counter-force base are arranged in a spaced mode, and the counter-force base can be prevented from slipping. The pushing method is based on the sliding device.

Description

Technical Field

[0001] The present invention relates to the technical field of viaduct construction, and particularly relates to a steel box girder sliding device and a steel box girder jacking method. Background Art

[0002] Steel box girders are structural forms commonly used in engineering. Especially in municipal viaducts, steel box girders have developed rapidly in China due to their good torsional resistance and fast construction speed. However, during the construction of steel box girder viaducts in urban sensitive areas, problems may be faced such as the viaduct needs to cross existing main roads and other ramp bridges, and spatially intersect with the main line concrete beam, ramp concrete beam, and steel beam. For example, in a reconstruction project of a certain scenic avenue, there are 17 spans of steel box girders in total, with a total weight of 26,000 tons. The steel box girders are numerous, have large spans, and complex structures. The construction environment faced includes traffic maintenance at the entrance of residential communities, traffic maintenance of the fire station passage, diversion roads on the ground along the existing scenic avenue, crossing flat intersections, crossing the main line viaduct, passing under the main viaduct of the scenic avenue, ramps crossing each other, crossing a water conveyance river, crossing a subway line, crossing a subway underground passage, etc. To solve the problem that the hoisting method cannot be used to construct steel box girders in some areas and ensure that the construction of steel box girders does not affect the traffic of surrounding residents, a steel box girder sliding device is required.

[0003] Existing steel box girder sliding devices include sliding shoes, hydraulic jacks, and reaction seats. The hydraulic jacks are hinged between the sliding shoes and the reaction seats. By the telescoping of the hydraulic jacks, the sliding shoes and the reaction seats are driven to slide alternately along the preset sliding track, so as to jack the steel box girder to the installation position. Among them, due to the large self-weight of the steel box girder (the maximum weight can reach 700t), the sliding shoes and the reaction seats are directly installed on the sliding track, and the resistance of the steel box girder sliding is large (the bottom of the sliding shoe is made of polytetrafluoroethylene, and the friction coefficient between it and the sliding track is about 0.05 - 0.1). Only relying on the vertical component force of the hydraulic jack acting on the reaction seat to press the reaction seat tightly on the sliding track, the phenomenon of the reaction seat slipping is likely to occur. Especially in the non-bracket section of the sliding track, when jacking the steel box girder, wedge blocks need to be inserted at the rear end of the reaction seat to avoid the reaction seat slipping, which seriously affects the construction efficiency. Summary of the Invention

[0004] Aiming at the technical problem that the reaction seat of the existing steel box girder sliding device is prone to slipping, the present invention provides a steel box girder sliding device and a steel box girder jacking method, which can reduce the normal pressure of the steel box girder acting on the sliding track and increase the normal pressure of the reaction seat during the jacking process, thereby reducing the resistance of the steel box girder sliding and increasing the sliding resistance of the reaction seat during the jacking process to avoid the reaction seat slipping and improve the construction efficiency of steel box girder installation.

[0005] The present invention is realized by the following technical solutions:

[0006] In a first aspect, the present invention provides a steel box girder sliding device, comprising: a sliding shoe for supporting the steel box girder and installed on a sliding track in a working state; a reaction seat installed on the sliding track in a working state and located behind the sliding shoe along the sliding direction of the sliding shoe; a hydraulic jack with two ends respectively hinged to the corresponding sliding shoe and the reaction seat, and the end hinged to the sliding shoe being higher than the other end; a counterweight connecting frame with one end hinged to the sliding shoe and capable of sliding relative to the reaction seat along the traveling direction of the sliding shoe; a counterweight assembly hinged to the other end of the counterweight connecting frame; wherein, during the movement of the sliding shoe, the middle part of the counterweight connecting frame presses down on the reaction seat, and the counterweight assembly is spaced from the sliding track; during the movement of the reaction seat, the counterweight assembly presses down on the sliding track, and the counterweight connecting frame is spaced from the reaction seat.

[0007] The steel box girder sliding device provided by the present invention includes a sliding shoe, a reaction seat, a hydraulic jack, a counterweight connecting frame and a counterweight assembly. The two ends of the hydraulic jack are respectively hinged to the corresponding sliding shoe and the reaction seat, and the end hinged to the sliding shoe is higher than the other end. One end of the counterweight connecting frame is hinged to the sliding shoe and can slide relative to the reaction seat along the traveling direction of the sliding shoe. The counterweight assembly is hinged to the other end of the counterweight connecting frame. When in use, the sliding shoe and the reaction seat are placed / installed on the sliding track, and the steel box girder is pressed on the sliding shoe. Since the end of the hydraulic jack hinged to the sliding shoe is higher than the end hinged to the reaction seat, the reaction seat is pressed against the sliding track under the vertical component of the reaction force. The middle part of the counterweight connecting frame presses down on the reaction seat, and the counterweight assembly is spaced from the sliding track. The counterweight assembly will apply an upward force to the sliding shoe through the counterweight connecting frame with the reaction seat as the fulcrum, thereby reducing the positive pressure of the steel box girder on the sliding track, and enabling the reaction seat to be pressed against the sliding track under the combined force of the gravity of the counterweight connecting frame and the counterweight assembly, the vertical component of the reaction force, and the reverse thrust force as the fulcrum, which can increase the positive pressure of the reaction seat during the pushing process, and further increase the sliding resistance of the reaction seat during the pushing process, ensuring that the friction force between the reaction seat and the sliding track is greater than the friction force between the sliding shoe and the sliding track, avoiding the slipping of the reaction seat, so as to push the steel box girder to move along the sliding track through the hydraulic jack and drive the counterweight connecting frame and the counterweight assembly to move towards the direction close to the sliding shoe.

[0008] When the hydraulic jack starts to contract, the counterweight assembly presses down on the sliding track, and the counterweight connecting frame and the reaction seat are spaced apart, so as to contact the resultant force of the gravity of the counterweight connecting frame and the counterweight assembly acting on the reaction force and the reverse thrust force as the fulcrum. At this time, the reaction seat is subjected to a pulling force pointing to the sliding shoe, the normal pressure acting on the sliding track is less than its own gravity, and the frictional force between it and the sliding track is less than the frictional force between the sliding shoe and the sliding track, so as to drive the reaction seat to move towards the sliding shoe by the contraction of the hydraulic jack. Thus, by fully extending and contracting the hydraulic jack, the steel box girder can be jacked and slid to the installation position.

[0009] Therefore, the steel box girder sliding device provided by the present invention can reduce the normal pressure of the steel box girder acting on the sliding track and increase the normal pressure of the reaction seat during the jacking process, thereby reducing the resistance of the steel box girder sliding and increasing the sliding resistance of the reaction seat during the jacking process, so as to avoid the reaction seat from slipping, and further improve the construction efficiency of the steel box girder installation.

[0010] In an optional embodiment of the present application, the reaction seat is provided with a support roller, and the support roller can support the middle part of the counterweight connecting frame during the movement of the sliding shoe, so as to reduce the resistance when the counterweight connecting frame slides relative to the reaction seat and ensure that the counterweight connecting frame can move simultaneously with the sliding shoe.

[0011] In an optional embodiment of the present application, the counterweight assembly includes: a counterweight member, the counterweight member is hinged to the counterweight connecting frame; a support hydraulic cylinder, the upper end of the support hydraulic cylinder is hinged to the counterweight member; wherein, the support hydraulic cylinder contracts during the movement of the sliding shoe and extends during the movement of the reaction seat, and the lower end abuts against the sliding track, so as to act the gravity of the counterweight member on the sliding track through the extension of the support hydraulic cylinder, and through the contraction of the support hydraulic cylinder, the counterweight assembly is spaced apart from the sliding track, so as to apply an upward acting force on the sliding shoe through the counterweight connecting frame with the reaction seat as the fulcrum.

[0012] In an optional embodiment of the present application, a support pad is hinged to the lower end of the support hydraulic cylinder to ensure that the lower end of the support hydraulic cylinder can abut against the sliding track when it extends.

[0013] In an alternative embodiment of the present application, a reversing control valve is further included; a first drive interface of the reversing control valve is simultaneously connected to an extension drive chamber of the hydraulic jack and a contraction drive chamber of the support hydraulic cylinder; a pressure switch is connected between the first drive interface and the contraction drive chamber of the support hydraulic cylinder, and the pressure switch is closed when the pressure of the first drive interface is greater than a first pressure value, and the first pressure value is less than the pressure required for the hydraulic jack to extend; a second drive interface of the reversing control valve is simultaneously connected to a contraction drive chamber of the hydraulic jack and an extension drive chamber of the support hydraulic cylinder; a one-way backpressure valve is connected between the first drive interface and the contraction drive chamber of the hydraulic jack, the one-way backpressure valve is conductive from the first drive interface to the hydraulic jack, and the backpressure of the one-way backpressure valve is greater than a second pressure value and less than a third pressure value, the second pressure value is the pressure required for the support hydraulic cylinder to lift the counterweight upward, and the third pressure value is the safety pressure of the support hydraulic cylinder; wherein, in a state where the backpressure of the one-way backpressure valve is greater than the second pressure value, the one-way backpressure valve is bidirectionally conductive.

[0014] Thus, the hydraulic jack and the support hydraulic cylinder are connected to the hydraulic oil supply system through the reversing control valve. When the reversing control valve controls the hydraulic oil to be output from the first drive interface, the hydraulic oil simultaneously enters the extension drive chamber of the hydraulic jack and the contraction drive chamber of the support hydraulic cylinder (flows back from the second drive interface). Since the hydraulic jack needs to push the sliding shoe when extending, and the support hydraulic cylinder only needs to pull the component connected to its piston rod away from the sliding track when contracting, therefore, the hydraulic oil output from the first drive interface first drives the support hydraulic cylinder to contract. After the support hydraulic cylinder contracts, the pressure of the hydraulic oil output from the first drive interface continues to increase. When its pressure is higher than the first pressure value, the pressure switch is closed to avoid damage to the support hydraulic cylinder caused by the increase in hydraulic oil pressure. At the same time, it makes the hydraulic oil output from the first drive interface act directly on the piston of the hydraulic jack, and then drives the hydraulic jack to extend. Thus, the support hydraulic cylinder contracts before the hydraulic jack extends, so that before pushing the sliding shoe, the counterweight assembly is spaced from the sliding track, so as to increase the positive pressure exerted by the reaction seat on the sliding track before pushing the sliding shoe, and avoid the phenomenon of the reaction seat slipping during the whole process of pushing the steel box girder.

[0015] When the reversing control valve controls the hydraulic oil to be output from the second driving interface, the hydraulic oil simultaneously enters the contraction driving chamber of the hydraulic jack and the extension driving chamber of the supporting hydraulic cylinder, and flows back from the first driving interface. Since a one-way back-pressure valve is connected between the first driving interface and the contraction driving chamber of the hydraulic jack, the one-way back-pressure valve is connected from the first driving interface to the hydraulic jack, and the back pressure of the one-way back-pressure valve is greater than the second pressure value but less than the third pressure value. At this time, the hydraulic oil of the second driving interface first pressurizes the extension driving chamber of the supporting hydraulic cylinder, and drives the supporting hydraulic cylinder to extend, so that the counterweight assembly is pressed down on the sliding track. In this process, the one-way back-pressure valve is in a one-way The guided and back pressure state makes it impossible for the hydraulic oil to drive the hydraulic jack to collect. When the supporting hydraulic cylinder lifts the counterweight upward, the hydraulic oil output by the second drive interface is greater than the second pressure value, so that the one-way back pressure valve opens, so that the hydraulic oil output by the second drive interface can drive the hydraulic jack to contract and drive the reaction seat to the top of the sliding shoe, so as to withdraw the counterweight connecting frame and the counterweight assembly gravity acting on the reaction seat and the reverse thrust as the fulcrum before dragging the reaction seat, so that when the reaction seat is dragged, the positive pressure acting on the sliding track is the weight of the reaction seat minus the upward component during dragging, thereby avoiding pulling the sliding shoe back during the process of dragging the reaction seat.

[0016] In an optional embodiment of the present application, the pressure switch includes: a pressure control valve body, in which a pressure control flow channel and a pressure control chamber are arranged; a pressure control piston, which is arranged in the pressure control chamber and divides the pressure control chamber into a pressure control sensing chamber and a pressure control action chamber, and the pressure control sensing chamber is connected to the pressure control flow channel; a pressure control valve core, which is arranged in the pressure control valve body and fixedly connected to the pressure control piston; a pressure control spring, which is used to drive the pressure control valve core to reset; when the pressure in the pressure control flow channel is greater than the first pressure value, the pressure control piston moves toward the pressure control action chamber to move the pressure control valve core and cut off the pressure control flow channel, so as to ensure that the pressure switch can be closed when the pressure in the contraction drive chamber of the supporting hydraulic cylinder is greater than the first pressure value.

[0017] In an optional embodiment of the present application, the one-way back-pressure valve includes: a back-pressure valve body, in which a conducting flow channel is arranged; a back-pressure valve core, which is arranged in the conducting flow channel and adapted to the conducting flow channel, and a one-way flow channel is arranged in the middle; a back-pressure spring, the force of which is between the back-pressure valve core and the corresponding structure of the back-pressure valve body to apply a set pressure to the back-pressure valve core; a one-way valve core, which is arranged in the conducting flow channel and can block the one-way flow channel; a one-way spring, the two ends of which are respectively connected to the one-way valve core and the corresponding structure of the back-pressure valve body, and when the one-way back-pressure valve is in a one-way conducting state, the one-way valve core is pressed against the port corresponding to the one-way flow channel to ensure that the one-way back-pressure valve can be conducted from the first drive interface to the hydraulic jack, and at the same time, two-way conduction is achieved when its back pressure is greater than a second pressure value.

[0018] In an alternative embodiment of the present application, the sliding shoe includes: a support seat for supporting the steel box girder, and the support seat is hinged to the hydraulic jack; a sliding pad installed at the lower end of the support seat, and the sliding pad is made of polytetrafluoroethylene material to reduce the friction between the sliding shoe and the sliding track while ensuring the smooth sliding of the sliding shoe.

[0019] In an alternative embodiment of the present application, the distance from the reaction seat to the counterweight assembly is greater than the distance from the reaction seat to the sliding shoe, so as to utilize the lever principle to reduce the weight of the required counterweight assembly and thereby reduce the load of the temporary support.

[0020] In a second aspect, the present invention provides a method for jacking a steel box girder, based on the above-mentioned steel box girder sliding device, including the following steps:

[0021] S10. Erect a temporary support on the sliding path of the steel box girder and install a sliding track on the temporary support;

[0022] S20. Place the sliding shoe and the reaction seat at corresponding positions on the sliding track;

[0023] S30. Hoist the steel box girder onto the sliding shoe;

[0024] S40. Synchronously control the alternate telescoping of the hydraulic jack and the support hydraulic cylinder to jack the steel box girder along the sliding track.

[0025] The method for jacking a steel box girder provided by the present invention, based on the above-mentioned steel box girder sliding device, first erects a temporary support on the sliding path of the steel box girder and installs a sliding track on the temporary support, then places the sliding shoe and the reaction seat at corresponding positions on the sliding track, then hoists the steel box girder onto the sliding shoe, and finally synchronously controls the alternate telescoping of the hydraulic jack and the support hydraulic cylinder. Thus, during the jacking process, the normal pressure of the steel box girder acting on the sliding track is reduced, and the normal pressure of the reaction seat during the jacking process is increased, which can avoid the slipping of the reaction seat and improve the construction efficiency of the installation of the steel box girder.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] 1. The steel box girder sliding device provided by the present invention includes sliding shoes, reaction seats, hydraulic jacks, counterweight connecting frames and counterweight components. The two ends of the hydraulic jack are respectively hinged to the corresponding sliding shoes and reaction seats, and the end hinged to the sliding shoes is higher than the other end. One end of the counterweight connecting frame is hinged to the sliding shoes and can slide relative to the reaction seat along the traveling direction of the sliding shoes. The counterweight component is hinged to the other end of the counterweight connecting frame. During use, the sliding shoes and reaction seats are placed / installed on the sliding track, and the steel box girder is pressed on the sliding shoes. When pushing the sliding shoes, the counterweight component will use the reaction seat as a fulcrum and apply an upward acting force on the sliding shoes through the counterweight connecting frame, thereby reducing the positive pressure of the steel box girder on the sliding track, increasing the positive pressure of the reaction seat during the pushing process, avoiding the slipping of the reaction seat, and further improving the construction efficiency of the steel box girder installation.

[0028] 2. The steel box girder pushing method provided by the present invention is based on the above-mentioned steel box girder sliding device. First, temporary supports are erected on the steel box girder sliding path, and sliding tracks are installed on the temporary supports. Then, the sliding shoes and reaction seats are placed at corresponding positions on the sliding track, and the steel box girder is hoisted onto the sliding shoes. Finally, the hydraulic jack and the support hydraulic cylinder are synchronously controlled to alternately extend and retract. Thus, during the pushing process, the positive pressure of the steel box girder on the sliding track is reduced, the positive pressure of the reaction seat during the pushing process is increased, the slipping of the reaction seat can be avoided, and the construction efficiency of the steel box girder installation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0030] In the drawings:

[0031] Figure 1 is a schematic structural diagram of a state during the movement of the sliding shoes of the steel box girder sliding device provided by the embodiment of the present application;

[0032] Figure 2 is a schematic structural diagram of a state during the movement of the reaction seat of the steel box girder sliding device provided by the embodiment of the present application;

[0033] Figure 3 is a schematic diagram of the hydraulic pipeline principle of the steel box girder sliding device provided by the embodiment of the present application;

[0034] Figure 4 is a schematic structural diagram of the pressure switch provided by the embodiment of the present application;

[0035] Figure 5Structural schematic diagram of the one-way backpressure valve provided by the embodiment of the present application.

[0036] Reference numerals in the drawings and corresponding component names:

[0037] 100 - slipper, 110 - support seat, 120 - sliding pad;

[0038] 200 - reaction seat, 210 - support roller;

[0039] 300 - hydraulic jack;

[0040] 400 - counterweight connecting frame;

[0041] 500 - counterweight assembly, 510 - counterweight, 520 - support hydraulic cylinder, 530 - support pad;

[0042] 600 - direction control valve;

[0043] 700 - pressure switch, 710 - pressure control valve body, 711 - pressure control flow channel, 712 - pressure control pressure sensing cavity, 713 - pressure control action cavity, 720 - pressure control piston, 730 - pressure control valve core, 740 - pressure control spring;

[0044] 800 - one-way backpressure valve, 810 - backpressure valve body, 811 - conduction flow channel, 812 - first limit step, 813 - second limit step, 814 - third limit step, 820 - backpressure valve core, 821 - one-way flow channel, 830 - backpressure spring, 840 - one-way valve core, 850 - one-way spring;

[0045] 900 - sliding track. Detailed implementation manners

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0048] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0049] In the description of the embodiments of the present application, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship in which the product of this application is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0050] In the description of the present application, unless otherwise clearly specified and limited, the terms "arranged", "installed", "connected", and "coupled" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0051] Embodiment 1

[0052] Combined with Figure 1 and Figure 2 , this embodiment provides a steel box girder sliding device, including: a sliding shoe 100 for supporting the steel box girder and installed on a sliding track 900 in a working state; a reaction seat 200 installed on the sliding track 900 in a working state and located behind the sliding shoe 100 along the sliding direction of the sliding shoe 100; a hydraulic jack 300 with both ends respectively hinged to the corresponding sliding shoe 100 and the reaction seat 200, and the end hinged to the sliding shoe 100 is higher than the other end; a counterweight connecting frame 400 with one end hinged to the sliding shoe 100 and capable of sliding relative to the reaction seat 200 along the traveling direction of the sliding shoe 100; a counterweight assembly 500 hinged to the other end of the counterweight connecting frame 400; wherein, during the movement of the sliding shoe 100, the middle part of the counterweight connecting frame 400 presses down on the reaction seat 200, and the counterweight assembly 500 is spaced from the sliding track 900. During the movement of the reaction seat 200, the counterweight assembly 500 presses down on the sliding track 900, and the counterweight connecting frame 400 is spaced from the reaction seat 200.

[0053] Specifically, the sliding shoe 100 includes: a support base 110 for supporting the steel box girder, and the support base 110 is hinged to the hydraulic jack 300; a sliding pad 120 installed at the lower end of the support base 110. The sliding pad 120 is made of polytetrafluoroethylene to reduce the frictional force between the sliding shoe 100 and the sliding track 900 while ensuring the smooth sliding of the sliding shoe 100.

[0054] It can be understood that the reaction seat 200 is provided with a support roller 210 which can support the middle part of the counterweight connecting frame 400 during the movement of the sliding shoe 100 to reduce the resistance when the counterweight connecting frame 400 slides relative to the reaction seat 200 and ensure that the counterweight connecting frame 400 can move simultaneously with the sliding shoe 100. At the same time, a limit groove or a limit retaining wheel can be provided on the reaction seat 200 to limit the side of the counterweight connecting frame 400 to prevent the counterweight connecting frame 400 from slipping off the support roller 210.

[0055] The counterweight connecting frame 400 can be a single steel bar, section steel, etc., or a combined structure of steel, which is specifically determined according to the weight of the counterweight assembly 500. Generally, the distance from the reaction seat 200 to the counterweight assembly 500 is greater than the distance from the reaction seat 200 to the sliding shoe 100, so as to utilize the lever principle to reduce the weight of the required counterweight assembly 500 and thus reduce the load of the temporary support.

[0056] In this embodiment, the counterweight assembly 500 includes: a counterweight member 510 hinged to the counterweight connecting frame 400; a support hydraulic cylinder 520 with its upper end hinged to the counterweight member 510. Wherein, the support hydraulic cylinder 520 contracts during the movement of the sliding shoe 100 and extends during the movement of the reaction seat 200, and its lower end abuts against the sliding track 900, so that the gravity of the counterweight member 510 acts on the sliding track 900 through the extension of the support hydraulic cylinder 520, and the counterweight assembly 500 is spaced from the sliding track 900 through the contraction of the support hydraulic cylinder 520, thereby applying an upward acting force on the sliding shoe 100 with the reaction seat 200 as the fulcrum and through the counterweight connecting frame 400.

[0057] Generally speaking, the counterweight 510 includes a mounting frame body, on which a plurality of lead blocks are mounted. The number of lead blocks can be increased or decreased according to actual requirements. At the same time, an active cavity is arranged in the middle of the mounting frame body, and the support hydraulic cylinder 520 is installed in the active cavity, so that the support hydraulic cylinder 520 can be received in the counterweight 510, and when it extends, the lower end can abut against the middle of the sliding track 900. And the support hydraulic cylinder 520 can tilt left and right in the active cavity, so that when the reaction seat 200 is towed, the support hydraulic cylinder 520 can lift the counterweight connecting frame 400 away from the reaction seat 200. Wherein, a support pad 530 is hinged to the lower end of the support hydraulic cylinder 520 to ensure that the lower end of the support hydraulic cylinder 520 can abut against the sliding track 900 when it extends.

[0058] On this basis, combined with Figure 3 , this embodiment further includes a reversing control valve 600; the first drive interface of the reversing control valve 600 is simultaneously connected to the extension drive chamber of the hydraulic jack 300 and the contraction drive chamber of the support hydraulic cylinder 520; a pressure switch 700 is connected between the first drive interface and the contraction drive chamber of the support hydraulic cylinder 520, and the pressure switch 700 is closed when the pressure of the first drive interface is greater than the first pressure value, and the first pressure value is less than the pressure required for the hydraulic jack 300 to extend; the second drive interface of the reversing control valve 600 is simultaneously connected to the contraction drive chamber of the hydraulic jack 300 and the extension drive chamber of the support hydraulic cylinder 520; a one-way backpressure valve 800 is connected between the first drive interface and the contraction drive chamber of the hydraulic jack 300, and the one-way backpressure valve 800 is conducted from the first drive interface to the hydraulic jack 300, and the backpressure of the one-way backpressure valve 800 is greater than the second pressure value and less than the third pressure value. The second pressure value is the pressure required for the support hydraulic cylinder 520 to lift the counterweight 510 upward, and the third pressure value is the safety pressure of the support hydraulic cylinder 520; wherein, in the state where the backpressure of the one-way backpressure valve 800 is greater than the second pressure value, the one-way backpressure valve 800 is bidirectionally conducted.

[0059] In this embodiment, the reversing control valve 600 is a three-position four-way solenoid valve. When the reversing control valve 600 is in the middle position, all its valve ports are in the closed state, thereby cutting off the hydraulic flow of the hydraulic jack 300 and the support hydraulic cylinder 520, so that the hydraulic jack 300 and the support hydraulic cylinder 520 maintain their current states without the need to add other valve bodies to make the hydraulic jack 300 and the support hydraulic cylinder 520 maintain a certain state. Of course, a two-position four-way valve, a two-position five-way valve, a three-position five-way valve, etc. can also be used.

[0060] Thus, the hydraulic jack 300 and the support hydraulic cylinder 520 are connected to the hydraulic oil supply system through the reversing control valve 600. When the reversing control valve 600 controls the hydraulic oil to output from the first drive interface, the hydraulic oil simultaneously enters the extension drive chamber of the hydraulic jack 300 and the contraction drive chamber of the support hydraulic cylinder 520 (returning from the second drive interface). Since the hydraulic jack 300 needs to push the sliding shoe 100 when extending, and the support hydraulic cylinder 520 only needs to pull the component connected to its piston rod away from the sliding track 900 when contracting, therefore, the hydraulic oil output from the first drive interface first drives the support hydraulic cylinder 520 to contract. After the support hydraulic cylinder contracts, the pressure of the hydraulic oil output from the first drive interface continues to rise. When its pressure is higher than the first pressure value, the pressure switch 700 closes to prevent the increase in hydraulic oil pressure from damaging the support hydraulic cylinder 520. At the same time, the hydraulic oil output from the first drive interface directly acts on the piston of the hydraulic jack 300, thereby driving the hydraulic jack 300 to extend. Thus, the support hydraulic cylinder 520 contracts before the hydraulic jack 300 extends, so that before pushing the sliding shoe 100, the counterweight assembly 500 is spaced from the sliding track, so as to increase the positive pressure exerted by the reaction seat 200 on the sliding track before pushing the sliding shoe 100, and prevent the reaction seat 200 from slipping during the entire process of pushing the steel box girder.

[0061] When the reversing control valve 600 controls the hydraulic oil to output from the second drive interface, the hydraulic oil simultaneously enters the contraction drive chamber of the hydraulic jack 300 and the extension drive chamber of the support hydraulic cylinder 520, and returns from the first drive interface. Since a one-way backpressure valve 800 is connected between the first drive interface and the contraction drive chamber of the hydraulic jack 300, the one-way backpressure valve 800 is conducted from the first drive interface to the hydraulic jack 300, and the backpressure of the one-way backpressure valve 800 is greater than the second pressure value and less than the third pressure value. At this time, the hydraulic oil at the second drive interface first pressurizes the extension drive chamber of the support hydraulic cylinder 520 and drives the support hydraulic cylinder 520 to extend, so that the counterweight assembly 500 is pressed down on the sliding track 900. During this process, the one-way backpressure valve 800 is in a one-way guiding and backpressure state, so that the hydraulic oil cannot drive the hydraulic jack 300 to retract. When the support hydraulic cylinder 520 jacks up the counterweight 510, the hydraulic oil output from the second drive interface is greater than the second pressure value, so that the one-way backpressure valve 800 opens, so that the hydraulic oil output from the second drive interface can drive the hydraulic jack 300 to contract, and drive the reaction seat 200 to push towards the sliding shoe 100, so as to withdraw the gravity of the counterweight connecting frame 400 and the counterweight assembly 500 acting on the reaction seat 200 and the reverse thrust as the fulcrum before pulling the reaction seat 200. Then, when the reaction seat 200 is pulled, the positive pressure exerted on the sliding track is the gravity of the reaction seat 200 minus the upward component force during pulling, so as to prevent the sliding shoe 100 from being pulled back during the process of pulling the reaction seat 200.

[0062] Combined with Figure 4 , the pressure switch 700 includes: a pressure control valve body 710, which is provided with a pressure control flow channel 711 and a pressure control cavity; a pressure control piston 720, which is arranged in the pressure control cavity and divides the pressure control cavity into a pressure control pressure sensing cavity 712 and a pressure control action cavity 713, and the pressure control pressure sensing cavity 712 is communicated with the pressure control flow channel 711; a pressure control valve core 730, which is arranged in the pressure control valve body 710 and is fixedly connected with the pressure control piston 720; a pressure control spring 740, which is used to drive the pressure control valve core 730 to reset; when the pressure in the pressure control flow channel 711 is greater than the first pressure value, the pressure control piston 720 moves towards the pressure control action cavity 713, so that the pressure control valve core 730 moves to cut off the pressure control flow channel 711, so as to ensure that the pressure switch 700 can be closed when the pressure in the contraction drive cavity of the support hydraulic cylinder 520 is greater than the first pressure value.

[0063] Combined with Figure 5 , the one-way back pressure valve 800 includes: a back pressure valve body 810, which is provided with a conduction flow channel 811; a back pressure valve core 820, which is arranged in the conduction flow channel 811 and is adapted to the conduction flow channel 811, and a one-way flow channel 821 is arranged in the middle; a back pressure spring 830, the acting force of which is between the back pressure valve core 820 and the corresponding structure of the back pressure valve body 810 to apply a set pressure to the back pressure valve core 820; a one-way valve core 840, which is arranged in the conduction flow channel 811 and can block the one-way flow channel 821; a one-way spring 850, the two ends of which are respectively connected with the one-way valve core 840 and the corresponding structure of the back pressure valve body 810, and in the state where the one-way back pressure valve 800 conducts unidirectionally, the one-way valve core 840 is abutted against the corresponding port of the one-way flow channel 821, so as to ensure that the one-way back pressure valve 800 can conduct from the first drive interface to the hydraulic jack 300, and at the same time, it can achieve bidirectional conduction when its back pressure is greater than the second pressure value.

[0064] Wherein, for the convenience of installing the internal components of the one-way back pressure valve 800, a through first limit step 812, a second limit step 813, and a third limit step 814 are sequentially arranged at intervals in the conduction flow channel 811 of the back pressure valve body 810. One end of the back pressure valve core 820 abuts against the side of the second limit step 813 facing the third limit step 814, and the acting force of the back pressure spring 830 is between the back pressure valve core 820 and the third limit step 814. Correspondingly, the two ends of the one-way spring 850 are respectively connected with the one-way valve core 840 and the first limit step 812.

[0065] In summary, the steel box girder sliding device provided in this embodiment includes a sliding shoe 100, a reaction seat 200, a hydraulic jack 300, a counterweight connecting frame 400, a counterweight assembly 500, a reversing control valve 600, a pressure switch 700, and a one-way backpressure valve 800. Both ends of the hydraulic jack 300 are respectively hinged to the corresponding sliding shoe 100 and the reaction seat 200, and the end hinged to the sliding shoe 100 is higher than the other end. One end of the counterweight connecting frame 400 is hinged to the sliding shoe 100 and can slide relative to the reaction seat 200 along the traveling direction of the sliding shoe 100. The counterweight assembly 500 is hinged to the other end of the counterweight connecting frame 400. The pressure switch 700 is connected between the first driving interface and the contraction driving chamber of the support hydraulic cylinder 520 (the pressure sensing chamber is directly communicated with the first driving interface, and pressure-free reflux can be achieved). The one-way backpressure valve 800 is connected between the first driving interface and the contraction driving chamber of the hydraulic jack 300.

[0066] During use, the sliding shoe 100 and the reaction seat 200 are placed / installed on the sliding track 900, and the steel box girder is pressed on the sliding shoe 100. The hydraulic jack 300 and the support hydraulic cylinder 520 are connected to the hydraulic oil supply system through the reversing control valve 600. When the reversing control valve 600 controls the hydraulic oil to be output from the first driving interface, the hydraulic oil simultaneously enters the extension driving chamber of the hydraulic jack 300 and the contraction driving chamber of the support hydraulic cylinder 520 (returning from the second driving interface). Since the hydraulic jack 300 needs to push the sliding shoe 100 when extending, while the support hydraulic cylinder 520 only needs to pull the component connected to its piston rod away from the sliding track 900 when contracting. Therefore, the hydraulic oil output from the first driving interface first drives the support hydraulic cylinder 520 to contract. After the support hydraulic cylinder contracts, the pressure of the hydraulic oil output from the first driving interface continues to increase. When its pressure is higher than the first pressure value, the pressure switch 700 closes to prevent the increase in hydraulic oil pressure from damaging the support hydraulic cylinder 520. At the same time, the hydraulic oil output from the first driving interface directly acts on the piston of the hydraulic jack 300, thereby driving the hydraulic jack 300 to extend. Thus, the support hydraulic cylinder 520 contracts before the hydraulic jack 300 extends, so that before pushing the sliding shoe 100, the counterweight assembly 500 is spaced from the sliding track, so as to increase the positive pressure exerted by the reaction seat 200 on the sliding track before pushing the sliding shoe 100.

[0067] Meanwhile, one end of the hydraulic jack 300 hinged to the sliding shoe 100 is higher than the end hinged to the reaction seat 200, and the reaction seat 200 is pressed against the sliding track 900 under the vertical component of the reaction force. The middle part of the counterweight connecting frame 400 presses down on the reaction seat 200, and the counterweight assembly 500 is arranged at an interval from the sliding track 900. The counterweight assembly 500 will apply an upward acting force on the sliding shoe 100 with the reaction seat 200 as the fulcrum through the counterweight connecting frame 400, thereby reducing the positive pressure of the steel box girder acting on the sliding track 900, and making the reaction seat 200 pressed against the sliding track 900 under the combined action of the gravity of the counterweight connecting frame 400 and the counterweight assembly 500, the vertical component of the reaction force, and the reverse thrust as the fulcrum, which can increase the positive pressure of the reaction seat 200 during the jacking process, and further increase the sliding resistance of the reaction seat 200 during the jacking process, ensuring that the friction force between the reaction seat 200 and the sliding track is greater than the friction force between the sliding shoe 100 and the sliding track, avoiding the slipping of the reaction seat 200, so as to jack the steel box girder along the sliding track through the hydraulic jack 300 and drive the counterweight connecting frame 400 and the counterweight assembly 500 to move in the direction close to the sliding shoe 100.

[0068] When the hydraulic jack 300 needs to start contracting, the control valve 600 is used to control the hydraulic oil to be output from the second drive interface. The hydraulic oil simultaneously enters the contraction drive chamber of the hydraulic jack 300 and the extension drive chamber of the support hydraulic cylinder 520, and returns from the first drive interface. Since a one-way backpressure valve 800 is connected between the first drive interface and the contraction drive chamber of the hydraulic jack 300, the one-way backpressure valve 800 is conducted from the first drive interface to the hydraulic jack 300, and the backpressure of the one-way backpressure valve 800 is greater than the second pressure value and less than the third pressure value. At this time, the hydraulic oil at the second drive interface first pressurizes the extension drive chamber of the support hydraulic cylinder 520 and drives the support hydraulic cylinder 520 to extend, so that the counterweight assembly 500 presses on the sliding track 900. During this process, the one-way backpressure valve 800 is in a one-way guiding and backpressure state, so that the hydraulic oil cannot drive the hydraulic jack 300 to retract. When the support hydraulic cylinder 520 jacks up the counterweight 510, the hydraulic oil output from the second drive interface is greater than the second pressure value, so that the one-way backpressure valve 800 is opened, so that the hydraulic oil output from the second drive interface can drive the hydraulic jack 300 to contract and drive the reaction seat 200 to push towards the sliding shoe 100, so as to withdraw the gravity of the counterweight connecting frame 400 and the counterweight assembly 500 acting on the reaction seat 200 and the reverse thrust as the fulcrum before dragging the reaction seat 200, and then making the positive pressure of the reaction seat 200 acting on the sliding track during the dragging process be the gravity of the reaction seat 200 minus the upward component force during dragging, avoiding pulling back the sliding shoe 100 during the process of dragging the reaction seat 200.

[0069] Moreover, since the counterweight assembly 500 presses down on the sliding track 900 and the counterweight connecting frame 400 is spaced from the reaction seat 200, the resultant force of the gravity of the counterweight connecting frame 400 and the counterweight assembly 500 acting on the reaction force and the reverse thrust force as the fulcrum is used. At this time, the reaction seat 200 is subjected to a pulling force pointing to the sliding shoe 100, the positive pressure acting on the sliding track 900 is less than its own gravity, and the frictional force between it and the sliding track is less than the frictional force between the sliding shoe 100 and the sliding track. By contracting the hydraulic jack 300, the reaction seat 200 can be driven to move in the direction close to the sliding shoe 100. Thus, by fully extending and contracting the hydraulic jack 300, the steel box girder can be jacked and slid to the installation station.

[0070] In summary, the steel box girder sliding device provided in this embodiment can reduce the positive pressure of the steel box girder acting on the sliding track 900 and increase the positive pressure of the reaction seat 200 during the jacking process, thereby reducing the resistance of the steel box girder sliding and increasing the sliding resistance of the reaction seat 200 during the jacking process to avoid slipping of the reaction seat 200 and further improving the construction efficiency of the steel box girder installation.

[0071] Embodiment 2

[0072] This embodiment provides a method for jacking a steel box girder. Based on the steel box girder sliding device described in Embodiment 1, it includes the following steps:

[0073] S10. Erect temporary supports on the sliding path of the steel box girder and install the sliding track 900 on the temporary supports.

[0074] Specifically, when building the temporary supports, it is necessary to pre-harden the ground and lay drainage ditches, etc., and build temporary piers at the corresponding positions. Then, the sliding track 900 is installed on the temporary supports to form a temporary overpass. The sliding track 900 is usually composed of double-pin HN1000*300 steel sections, with 8mm slideway steel plates + 4mm thick stainless steel plates laid on top.

[0075] Generally, the standard section of the slideway is 12m long and is connected by welding. To ensure the smoothness of the slideway, the joints of the stainless steel plates are polished flat. To ensure the smoothness of the steel beam sliding process, the accuracy after reaching the position, and reduce the on-site adjustment workload, it is necessary to ensure the processing and installation quality of the slideway, where the flatness of the slideway plane ≤ 20mm, the height difference of the slideway ≤ 2mm, the slideway and the stainless steel sliding surface must be welded and polished smoothly, and the transition is smooth.

[0076] S20. Place the sliding shoe 100 and the reaction seat 200 at the corresponding positions on the sliding track 900.

[0077] Specifically, there are usually four sliding shoes 100 arranged in an array, and only two sliding shoes 100 on the same side as the starting section are counterweighted with a hydraulic jack 300 and a reaction seat 200. At the same time, the control support hydraulic cylinder 520 is in an extended state, and the counterweight assembly 500 is made to abut against the sliding track 900.

[0078] S30. Hoist and install the steel box girder on the sliding shoe 100.

[0079] S40. Synchronously control the alternate expansion and contraction of the hydraulic jack 300 and the support hydraulic cylinder 520 to push the steel box girder along the sliding track 900.

[0080] Specifically, when the reversing control valve 600 controls the hydraulic oil to be output from the first drive interface, the hydraulic oil simultaneously enters the extension drive chamber of the hydraulic jack 300 and the contraction drive chamber of the support hydraulic cylinder 520 (returning from the second drive interface). Since the hydraulic jack 300 needs to push the sliding shoe 100 when it extends, and the support hydraulic cylinder 520 only needs to pull the component connected to its piston rod away from the sliding track 900 when it contracts, therefore, the hydraulic oil output from the first drive interface first drives the support hydraulic cylinder 520 to contract. After the support hydraulic cylinder contracts, the pressure of the hydraulic oil output from the first drive interface continues to rise. When its pressure is higher than the first pressure value, the pressure switch 700 closes to prevent damage to the support hydraulic cylinder 520 caused by the rising hydraulic oil pressure. At the same time, it makes the hydraulic oil output from the first drive interface act directly on the piston of the hydraulic jack 300, thereby driving the hydraulic jack 300 to extend. Thus, the support hydraulic cylinder 520 contracts before the hydraulic jack 300 extends, so that before pushing the sliding shoe 100, the counterweight assembly 500 is spaced apart from the sliding track, in order to increase the positive pressure exerted by the reaction seat 200 on the sliding track before pushing the sliding shoe 100.

[0081] When the reversing control valve 600 controls the hydraulic oil to be output from the second drive interface, the hydraulic oil simultaneously enters the contraction drive chamber of the hydraulic jack 300 and the extension drive chamber of the support hydraulic cylinder 520, and returns from the first drive interface. Since a one-way backpressure valve 800 is connected between the first drive interface and the contraction drive chamber of the hydraulic jack 300, the one-way backpressure valve 800 is conducted from the first drive interface to the hydraulic jack 300, and the backpressure of the one-way backpressure valve 800 is greater than the second pressure value and less than the third pressure value. At this time, the hydraulic oil at the second drive interface first pressurizes the extension drive chamber of the support hydraulic cylinder 520 and drives the support hydraulic cylinder 520 to extend, so that the counterweight assembly 500 presses down on the sliding track 900. During this process, the one-way backpressure valve 800 is in a one-way guiding and backpressure state, so that the hydraulic oil cannot drive the hydraulic jack 300 to retract. When the support hydraulic cylinder 520 jacks up the counterweight 510, the hydraulic oil output from the second drive interface is greater than the second pressure value, so that the one-way backpressure valve 800 is opened, so that the hydraulic oil output from the second drive interface can drive the hydraulic jack 300 to contract, and drive the reaction seat 200 to top against the sliding shoe 100, so as to withdraw the gravity of the counterweight connecting frame 400 and the counterweight assembly 500 acting on the reaction seat 200 and the reverse thrust force as the fulcrum before pulling the reaction seat 200. Then, when the reaction seat 200 is pulled, the positive pressure acting on the sliding track is the gravity of the reaction seat 200 minus the upward component force during pulling, so as to avoid pulling back the sliding shoe 100 during the process of pulling the reaction seat 200.

[0082] In summary, the steel box girder jacking method provided in this embodiment is based on the steel box girder sliding device described in Embodiment 1. First, temporary supports are erected on the steel box girder sliding path, and the sliding track 900 is installed on the temporary supports. Then, the sliding shoes 100 and the reaction seats 200 are placed at corresponding positions on the sliding track 900, and then the steel box girder is hoisted on the sliding shoes 100. Finally, the hydraulic jack 300 and the support hydraulic cylinder 520 are synchronously controlled to alternately expand and contract. Thus, during the jacking process, the positive pressure exerted by the steel box girder on the sliding track 900 is reduced, and the positive pressure of the reaction seat 200 during the jacking process is increased, which can prevent the reaction seat 200 from slipping and improve the construction efficiency of the steel box girder installation.

[0083] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A steel box girder sliding device, characterized in that: include: A sliding shoe (100), used for supporting the steel box girder, is installed on the sliding track (900) in a working state; A reaction seat (200) is installed on the sliding track (900) in a working state and is located behind the sliding shoe (100) along the sliding direction of the sliding shoe (100); A hydraulic jack (300), the two ends of which are respectively hinged to the corresponding sliding shoe (100) and the reaction seat (200), and one end hinged to the sliding shoe (100) is higher than the other end; A counterweight connecting frame (400), one end of which is hinged to the sliding shoe (100) and is capable of sliding relative to the reaction seat (200) along the travel direction of the sliding shoe (100); A counterweight assembly (500) is hinged to the other end of the counterweight connecting frame (400); Wherein, during the movement of the sliding shoe (100), the middle part of the counterweight connecting frame (400) is pressed down on the reaction seat (200), and the counterweight assembly (500) and the sliding track (900) are spaced apart; during the movement of the reaction seat (200), the counterweight assembly (500) is pressed down on the sliding track (900), and the counterweight connecting frame (400) and the reaction seat (200) are spaced apart.

2. The steel box girder sliding device according to claim 1, characterized in that: The reaction seat (200) is provided with a support roller (210), and the support roller (210) is capable of supporting the middle part of the counterweight connecting frame (400) during the movement of the sliding shoe (100).

3. The steel box girder sliding device according to claim 1, characterized in that: The counterweight assembly (500) comprises: A counterweight member (510), the counterweight member (510) being hingedly connected to the counterweight connecting frame (400); A supporting hydraulic cylinder (520), the upper end of which is hinged to the counterweight (510); The supporting hydraulic cylinder (520) contracts during the movement of the sliding shoe (100), extends during the movement of the reaction seat (200), and the lower end contacts the sliding track (900).

4. The steel box girder sliding device according to claim 3, characterized in that: A support pad (530) is hingedly connected to the lower end of the supporting hydraulic cylinder (520).

5. The steel box girder sliding device according to claim 3, characterized in that: Also includes a reversing control valve (600); The first drive interface of the reversing control valve (600) is simultaneously connected to the extension drive chamber of the hydraulic jack (300) and the contraction drive chamber of the supporting hydraulic cylinder (520); A pressure switch (700) is connected between the first drive interface and the contraction drive chamber of the supporting hydraulic cylinder (520), and the pressure switch (700) is closed when the pressure of the first drive interface is greater than a first pressure value, and the first pressure value is less than the pressure required for the hydraulic jack (300) to extend; The second drive interface of the reversing control valve (600) is simultaneously connected to the contraction drive chamber of the hydraulic jack (300) and the extension drive chamber of the supporting hydraulic cylinder (520); A one-way back pressure valve (800) is connected between the first drive interface and the contraction drive chamber of the hydraulic jack (300), the one-way back pressure valve (800) is connected from the first drive interface to the hydraulic jack (300), and the back pressure of the one-way back pressure valve (800) is greater than a second pressure value and less than a third pressure value, the second pressure value is the pressure required for the supporting hydraulic cylinder (520) to lift the counterweight (510) upward, and the third pressure value is the safety pressure of the supporting hydraulic cylinder (520); Wherein, when the back pressure of the one-way back pressure valve (800) is greater than the second pressure value, the one-way back pressure valve (800) is bidirectionally conductive.

6. The steel box girder sliding device according to claim 5, characterized in that: The pressure switch (700) comprises: A pressure control valve body (710) is provided with a pressure control flow channel (711) and a pressure control cavity; A pressure control piston (720) is disposed in the pressure control chamber and divides the pressure control chamber into a pressure control sensing chamber (712) and a pressure control action chamber (713); the pressure control sensing chamber (712) is in communication with the pressure control flow channel (711); A pressure control valve core (730), arranged in the pressure control valve body (710) and fixedly connected to the pressure control piston (720); A pressure control spring (740), used for driving the pressure control valve core (730) to reset; When the pressure in the pressure control flow channel (711) is greater than a first pressure value, the pressure control piston (720) moves toward the pressure control action chamber (713) to move the pressure control valve core (730) to cut off the pressure control flow channel (711).

7. The steel box girder sliding device according to claim 5, characterized in that: The one-way back pressure valve (800) comprises: A back pressure valve body (810) is provided with a conducting flow channel (811); A back pressure valve core (820) is arranged in the conducting flow channel (811) and is adapted to the conducting flow channel (811), and a one-way flow channel (821) is arranged in the middle; A back pressure spring (830) having an acting force between the back pressure valve core (820) and a corresponding structure of the back pressure valve body (810) so as to apply a set pressure to the back pressure valve core (820); A one-way valve core (840) is disposed in the conducting flow channel (811) and is capable of blocking the one-way flow channel (821); The one-way spring (850) has two ends connected to the one-way valve core (840) and the corresponding structures of the back pressure valve body (810) respectively, and when the one-way back pressure valve (800) is in a one-way conducting state, the one-way valve core (840) is pressed against the corresponding port of the one-way flow channel (821).

8. The steel box girder sliding device according to any one of claims 1 to 7, characterized in that: The sliding shoe (100) comprises: A support seat (110), the support seat (110) is used to support the steel box girder, and the support seat (110) is hinged to the hydraulic jack (300); A sliding pad (120), wherein the sliding pad (120) is installed at the lower end of the support seat (110), and the sliding pad (120) is made of polytetrafluoroethylene.

9. The steel box girder sliding device according to any one of claims 1 to 7, characterized in that: The distance from the reaction seat (200) to the counterweight assembly (500) is greater than the distance from the reaction seat (200) to the sliding shoe (100).

10. A method for pushing a steel box girder, characterized in that: The steel box girder sliding device according to any one of claims 3 to 9 comprises the following steps: S10, erecting a temporary support on the sliding path of the steel box girder, and installing a sliding track (900) on the temporary support; S20, placing the sliding shoe (100) and the reaction seat (200) at corresponding positions on the sliding track (900); S30, hoisting the steel box girder onto the sliding shoe (100); S40, synchronously controlling the hydraulic jack (300) and the supporting hydraulic cylinder (520) to extend and retract alternately, so as to push the steel box girder along the sliding track (900).

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