Construction method for continuous porous super-low frame bridge with oblique jacking

Abstract

The application discloses a continuous porous super-low-position frame bridge oblique jacking construction method, which comprises the following steps: S1, completing railway line overhead reinforcement operation; S2, excavating a working pit on one side of the railway line while performing the step S1, applying a sliding plate and a lubricating isolation layer on the bottom surface of the working pit, and applying a backup pile; S3, prefabricating each frame bridge on the lubricating isolation layer; S4, installing jacking equipment between each frame bridge and the backup pile; S5, first, synchronously jacking the No.1 frame bridge and the No.4 frame bridge on both sides through the jacking equipment, and then, synchronously jacking the No.2 frame bridge and the No.3 frame bridge in the middle after the No.1 frame bridge and the No.4 frame bridge are jacked into position; S6, filling and compacting each frame bridge by using concrete, and filling the upper part of each frame bridge by using coarse sand and ballast; S7, removing the jacking equipment and restoring the railway line. The application can ensure balanced operation of the jacking equipment and reduce the influence on the existing railway line.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of frame bridge construction. More particularly, the present application relates to a method for oblique jacking construction of continuous multi-hole ultra-low frame bridge. BACKGROUND

[0002] When a new planned highway line intersects with an existing railway line, the conventional method is to jacking the frame bridge cast in situ on one side of the railway line to the railway below to butt joint the highway line. The existing frame bridge jacking generally has a single frame bridge jacking with multiple holes, or a plurality of frame bridges jacking synchronously with very small spacing. A municipal engineering needs to pass under the Guangzhou-Zhuhai bullet train running line with four-hole separated frame bridges, the included angles of the four-hole frame bridges with the existing Guangzhou-Zhuhai bullet train running line are 56°-59°, the interval between each frame bridge is 5-6m, and the respective jacking routes are not completely parallel. The synchronous jacking of the four-hole frame bridges needs to invest a large amount of jacking equipment and monitoring equipment, and the construction has a large influence on the existing railway line, and at the same time needs to ensure the spacing between the frame bridges during jacking and after jacking. Therefore, a new construction method is needed to reduce the influence on the existing railway line and consider the balanced operation of the jacking equipment. SUMMARY

[0003] An object of the present application is to solve at least the above problems and provide at least the advantages to be described later.

[0004] In order to achieve these objects and other advantages according to the present application, a method for oblique jacking construction of continuous multi-hole ultra-low frame bridge is provided, including four-hole frame bridges, adjacent two-hole frame bridges are spaced apart by a certain distance, and the method comprises the following steps:

[0005] S1, completing railway line overhead reinforcement work;

[0006] S2, excavating a working pit on one side of the railway line while performing step S1, laying a sliding plate and a lubricating isolation layer on the bottom surface of the working pit, and laying a backup pile on the side of the working pit away from the railway line;

[0007] S3, prefabricating each of the frame bridges on the lubricating isolation layer, and sequentially arranging No. 1 frame bridge, No. 2 frame bridge, No. 3 frame bridge and No. 4 frame bridge along the extension direction of the railway line;

[0008] S4, installing jacking equipment between each of the frame bridges and the backup pile;

[0009] S5, first jacking No. 1 frame bridge and No. 4 frame bridge on both sides synchronously through the jacking equipment, then jacking No. 2 frame bridge and No. 3 frame bridge in the middle synchronously after jacking into position;

[0010] S6, the transition section between each frame bridge and the earth collapse on both sides is filled and compacted with concrete, and the upper part of each frame bridge is backfilled with coarse sand and ballast;

[0011] S7, remove the jacking equipment and restore the railway line.

[0012] Preferably, the top of one side of each frame bridge towards the railway line is provided with a steel blade angle, and in step S5, each frame bridge is first jacked to the steel blade angle into the railway roadbed by the jacking equipment, and then the earth inside the frame bridge is excavated and the jacking of the jacking equipment is alternately performed until the frame bridge is jacked to the predetermined position.

[0013] Preferably, in step S5, during each jacking process of the jacking equipment, the axis and elevation of the frame bridge are observed when the frame bridge advances a certain jacking distance, and the deviation of the jacking direction or elevation of the frame bridge is corrected in time.

[0014] Preferably, in step S4, two sets of jacking equipment are provided between each frame bridge and the corresponding back pile, and the two sets of jacking equipment are respectively arranged on both sides of the central axis of the frame bridge; the jacking equipment comprises a plurality of jacks and a jacking iron assembly arranged between each jack and the back pile, the axis of the jacking iron assembly is on the same straight line as the axis of the jack, and is parallel to the jacking path.

[0015] Preferably, the jacking iron assembly comprises a plurality of jacking columns connected in sequence and centered, and a counter-pressure device is arranged at the connection between adjacent two jacking columns in the same jacking iron assembly; two adjacent counter-pressure devices in different jacking iron assemblies are connected through a fine adjustment connecting piece; the fine adjustment connecting piece is arranged between each jack and the corresponding jacking iron assembly.

[0016] Preferably, the fine adjustment connecting piece comprises a fixed block, a movable block and an intermediate block arranged between the two; the intermediate block is sleeved on a screw rod and is threadedly connected with the screw rod, one end of the screw rod is connected with a driving motor; one end of the intermediate block towards the fixed block is provided with a wedge block with the same height as the intermediate block, the wedge block has a right triangle structure and the inclined surface thereof faces the fixed block, and a slant groove matched with the wedge block is formed in the fixed block; the side of the intermediate block towards the movable block is vertically slidably connected with the movable block; slide grooves are formed on both sides of the fixed block, and slide rails corresponding to the slide grooves are arranged on both sides of the movable block, and one end of the slide rail extends into the corresponding slide groove.

[0017] Preferably, the height of the intermediate block is 1 / 2 to 2 / 3 of the height of the fixed block, and the slant groove is longitudinally arranged along the vertical direction.

[0018] Preferably, the fine adjustment connector between the jack and the top iron assembly is fixedly connected with the corresponding top column.

[0019] Preferably, in the same set of jacking equipment, the outer side of the counter-pressure device in the top iron assembly on both sides is fixedly connected with an anchor rod through a connecting plate, one end of the anchor rod being anchored to the sliding plate or the bottom of the working pit.

[0020] Preferably, the counter-pressure device comprises a counter-pressure pier, which is a concrete pier column with a reverse concave shape in cross section, two side jacks being arranged on the inner walls of the two sides of the counter-pressure pier respectively corresponding to the two top columns, and a plurality of upper jacks being arranged on the inner top surface of the counter-pressure pier respectively corresponding to the two top columns, each of the upper jacks being connected with the inner top surface of the counter-pressure pier through a spherical hinge support; the side jacks and the upper jacks are of telescopic structure.

[0021] The present application at least includes the following beneficial effects:

[0022] The continuous multi-hole ultra-low position frame bridge diagonal jacking construction method provided by the present application jacks in batches, jacks in the frame bridges on both sides first, then jacks in the frame bridges in the middle, and then fills the space between the adjacent frame bridges and between the frame bridges on the outside and the railway roadbed, which ensures the jacking construction efficiency through the jacking equipment and reduces the influence on the existing railway line as much as possible under the condition of not too much investment in jacking equipment and monitoring equipment.

[0023] Other advantages, objects, and features of the present application will be apparent from the following description, and will be understood by persons skilled in the art. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 FIG. 1 is a plan structure schematic diagram of the frame bridge jacked into position according to the present application;

[0025] Figure 2 FIG. 2 is a cross-sectional structure schematic diagram of the frame bridge according to the present application;

[0026] Figure 3 FIG. 3 is a plan structure schematic diagram of the jacking assembly according to the present application;

[0027] Figure 4 FIG. 4 is a plan structure schematic diagram of the fine adjustment connector according to the present application;

[0028] Figure 5 FIG. 5 is a Figure 4 A-A cross-sectional structure schematic diagram according to the present application;

[0029] Figure 6The elevation structure diagram of the counter-pressure device. DETAILED DESCRIPTION

[0030] The application will be further described in conjunction with the accompanying drawings so that those skilled in the art can implement the application according to the description and drawings.

[0031] It should be noted that the experimental methods in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the application, the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0032] As shown in Figure 1 and Figure 2 The application provides a continuous multi-hole ultra-low frame bridge skew jacking construction method, which comprises four-hole frame bridges, adjacent two-hole frame bridges are spaced apart by a certain distance, and comprises the following steps:

[0033] S1, completing overhead reinforcement of the railway line 1;

[0034] S2, excavating a working pit on one side of the railway line 1 while performing step S1, laying a sliding plate 9 and a lubricating isolation layer on the bottom surface of the working pit, and laying a backup pile 7 on the side of the working pit away from the railway line;

[0035] S3, prefabricating each of the frame bridges on the lubricating isolation layer, and sequentially arranging a No. 1 frame bridge 2, a No. 2 frame bridge 3, a No. 3 frame bridge 4 and a No. 4 frame bridge 5 along the extension direction of the railway line;

[0036] S4, installing jacking equipment 8 between each of the frame bridges and the backup pile 7;

[0037] S5, first synchronously jacking the No. 1 frame bridge 2 and the No. 4 frame bridge 5 on both sides through the jacking equipment 8, and then synchronously jacking the No. 2 frame bridge 3 and the No. 3 frame bridge 4 in the middle after the No. 1 frame bridge 2 and the No. 4 frame bridge 5 are jacked into place;

[0038] S6, filling and compacting with concrete for the transition sections where earth collapse occurs between each of the frame bridges and on both sides, and backfilling the upper part of each of the frame bridges with coarse sand and ballast;

[0039] S7, removing the jacking equipment 8 and restoring the railway line 1.

[0040] In the technical solution, the overhead reinforcement work of the railway line 1 and the work pit work are performed synchronously. In step S2, the work pit work is performed in the following sequence: S21, construction of work pit retaining piles and water stop curtain and artificial hole digging back pile; S22, excavation of the work pit to the back pile and drainage of the foundation pit; S23, pouring of the sliding plate, lubrication of the isolation layer and construction of the back. Then, each frame bridge is prefabricated on the lubrication isolation layer, and after the strength of each frame bridge reaches 100%, the jacking equipment 8 is installed. In order to reduce the influence on the existing railway line and the balance work of the jacking equipment, the four-hole frame bridge is jacked in two times, in which the first time is to synchronously jack the No. 1 frame bridge 2 and the No. 4 frame bridge 5 on the two sides, and the second time is to jack the No. 2 frame bridge 3 and the No. 3 frame bridge 4 in the middle.

[0041] Further, each frame bridge is provided with a steel blade corner at the top of the side facing the railway line 1. In step S3, when the frame bridge is prefabricated, the steel blade corner 6 is installed after the strength of the frame bridge culvert body concrete reaches 70%, and the jacking construction is performed after the strength of the concrete reaches 100%. In step S5, when each frame bridge is jacked, it is first jacked to the steel blade corner 6 cut into the railway roadbed, and then the excavation in the frame bridge and the jacking of the jacking equipment are alternately performed until the frame bridge is jacked to the predetermined position. Before the steel blade corner 6 is cut into the railway roadbed, the frame bridge will be jacked for an end distance in the jacking direction, and within the distance range, guide piers are arranged on the two sides of the jacking line of the frame bridge, and the guide piers are oriented towards the guide rail on one side of the frame bridge. The guide piers and the guide rail guide the jacking direction of the frame bridge when jacking. After the steel blade corner 6 is cut into the railway roadbed, the excavation and transportation in the frame bridge are performed by the excavation equipment, and the roadbed soil is excavated in sections and layers. The first layer is excavated from the opposite side of the jacking frame to the railway to a position 6m away from the railway, forming an excavation channel. The second layer is excavated along with the jacking, and the excavation face width is greater than the frame bridge width by 20mm-50mm, and the excavation depth of the second layer is the same as the jacking distance each time. If the foundation soil layer after excavation does not meet the design or does not reach the designed bearing capacity, grouting is required to reinforce the foundation before jacking.

[0042] In step S5, the frame bridge is observed in axis and elevation every time the jacking equipment jacks, and the jacking direction or elevation of the frame bridge is corrected in time when deviation occurs. Observation points are set behind each frame bridge before jacking construction, and the deviation of the center line and the horizontal difference of each frame bridge are measured by instruments every time the jacking equipment jacks. A control baseline is set by the axis of the box body and another baseline parallel to it, and the baseline stake should be a certain distance away from the back of the foundation pit to avoid incorrect observation caused by deformation of the back. Two horizontal observation points are set on both sides of the jacking plate of the frame bridge, and the observation points should be arranged to ensure visibility and avoid interference with observation during jacking construction. The left-right direction deviation of the frame bridge can be adjusted by the jacking equipment 8, and the elevation direction deviation of the frame bridge can be corrected by excavating the excavation surface to be flush with the bottom of the box or over-excavating to correct the frame bridge lifting head, so that the steel blade angle 6 eats more soil, or the excavation surface is kept above the bottom of the box during excavation to correct the frame bridge lifting head.

[0043] In step S6, during the excavation of the foundation pit in the jacking path, the lateral foundation pit may cause a certain degree of soil rupture surface or collapse, which poses a safety hazard to the roadbed. After each frame bridge is jacked into position, the transition section between the frame bridges and the soil collapse on both sides is filled and compacted with plain concrete or cement mortar, and the concrete height is flush with the frame. The cement mortar grouting is generally carried out in the area of the rupture surface. The upper part of each frame bridge and the railway line 1 are backfilled with water-permeable coarse sand and first-class ballast. The 30m range of the transition section affecting the track bed is replaced with 50cm of ballast and tamped and compacted to ensure the stability of the roadbed.

[0044] In step S7, each frame bridge is provided with transverse blind drainages at the upper, middle and lower parts, the overhead equipment is removed by slow-moving points, and the track bed is tamped and compacted by small machinery. After the overhead equipment is removed and the line is restored, the line is repaired at a speed of 45km / h for not less than 12 hours, and then the normal speed is gradually restored every 24 hours.

[0045] In order to facilitate the control of the jacking direction of multiple frame bridges during jacking, two sets of jacking equipment 8 are provided between each frame bridge and the corresponding back pile in step S4, and the two sets of jacking equipment 8 are arranged on both sides of the central axis of the frame bridge. The jacking equipment 8 includes multiple jacks and a jacking iron assembly arranged between each jack and the back pile, the axis of the jacking iron assembly is on the same straight line as the axis of the jack, and is parallel to the jacking path. Each jack on the same side is connected to the same high-pressure oil pump, the oil pump is controlled and operated by electrical equipment, and two hydraulic oil pump electrical control consoles are provided to enable the two frame bridges to be jacked synchronously.

[0046] To reduce the free length of the jacks and increase stability, the traditional construction method is to make the length and position of the jacks consistent, and set a beam every 4-8m, and use square wood to tighten the jacks. However, this method cannot guarantee that the axes of the jacks and the corresponding jack assemblies are in the same straight line, which affects the control of the jacking direction of the frame bridge during jacking. To solve this problem, in another embodiment, as shown in Figure 3 , the jack assembly includes a plurality of jacking columns 81 connected in sequence and centered, and a counter-pressure device 82 is arranged at the connection between two adjacent jacking columns 81 in the same jack assembly; two adjacent counter-pressure devices 82 in different jack assemblies are connected by a fine adjustment connecting piece 85; the fine adjustment connecting piece 85 is arranged between each jack and the corresponding jack assembly.

[0047] The sequential and centered connection of each jacking column 81 in the same jack assembly can guarantee that the axes of the jack assembly and the jacks are in the same straight line. By using the counter-pressure device 82 instead of the beam, the connection between the two adjacent jacking columns 81 can be prevented from being raised or even jumping out during jacking, which guarantees the stability and support of the jack assembly and prevents the frame bridge from deviating in the left-right direction due to the jack assembly during jacking. By using the fine adjustment connecting piece 85 instead of the square wood to tighten, the distance between the two adjacent rows of jack assemblies in the horizontal direction can be adjusted flexibly. The distance between the jack and the corresponding jack assembly is also adjusted by the fine adjustment connecting piece 85. When the frame bridge deviates in the left-right direction during jacking, the fine adjustment connecting piece 85 on one side of the frame bridge can be elongated to wedge the corresponding jacks and jacking columns, and the fine adjustment connecting piece 85 on the other side can be shortened to wedge the fine adjustment connecting piece 85 and the corresponding jacks, or a gap of 1-3cm is left. The fine adjustment connecting piece 85 can be quickly and accurately adjusted, which guarantees the efficiency of jacking construction.

[0048] Further, refer to Figure 4 and Figure 5The fine adjustment connecting piece 85 comprises a fixed block 851, a movable block 855 and an intermediate block 857 arranged between the two; the intermediate block 857 is sleeved on a screw rod 859 and is threadedly connected with the screw rod 859, one end of the screw rod 859 is connected with a driving motor 10; one end of the intermediate block 857 towards the fixed block 851 is provided with a wedge block 858 which is in the same height as the intermediate block 857, the wedge block 858 is in a right triangle structure and the inclined surface thereof faces the fixed block 851, the fixed block 851 is provided with an inclined groove 852 which matches the wedge block 858; one side of the intermediate block 857 towards the movable block 855 is vertically slidably connected with the movable block 855; both sides of the fixed block 851 are provided with sliding grooves 853, both sides of the movable block 855 are correspondingly provided with sliding rails 854; one end of the sliding rail 854 extends into the corresponding sliding groove 853.

[0049] The driving motor 10 is slidably arranged on the fixed block 851, the output end of the driving motor 10 is fixedly connected with the screw rod 859 so as to drive the screw rod 859 to rotate, specifically, a horizontal rail can be fixedly arranged on the fixed block 851 to support the driving motor 10, when the driving motor 10 drives the screw rod 859 to rotate, the intermediate block 857 slides along the horizontal rail. When it is needed to extend the fine adjustment connecting piece 85, the driving motor 10 drives the screw rod 859 to rotate so as to make the intermediate block 857 go down, at the same time, the wedge block 858 goes down along the inclined groove 852, thereby driving the movable block 855 to move away from the fixed block 851, the length of the whole fine adjustment connecting piece 85 is extended; when it is needed to contract the fine adjustment connecting piece 85, the driving motor 10 drives the screw rod 859 to rotate so as to make the intermediate block 857 go up, at the same time, the wedge block 858 goes up along the inclined groove 852, thereby driving the movable block 855 to move towards the fixed block 851, the length of the whole fine adjustment connecting piece 85 is shortened. Refer to Figure 4 One side of the intermediate block 857 towards the movable block 855 is provided with a dovetail sliding block 856, the movable block 855 is correspondingly provided with a dovetail sliding groove, when the wedge block 858 slides along the inclined groove 852, the dovetail sliding block 856 slides along the dovetail sliding groove and drives the movable block 855 to slide relative to the fixed block 851. The sliding groove 853 and the sliding rail 854 provide guidance and limiting support for the sliding of the movable block 855. The fixed block 851 and the movable block 855 can be respectively connected with the counter-pressure device 82 through connecting flanges.

[0050] Further, the height of the intermediate block 857 is 1 / 2~2 / 3 of the height of the fixed block 851, and the inclined groove 852 is vertically arranged along the length. The height difference between the intermediate block 857 and the fixed block 851 is the adjustment range of the intermediate block 857 on the screw rod 859. When the bottom surface of the intermediate block 857 is flush with the bottom surface of the fixed block 851, the length of the fine adjustment connector 85 is the longest; when the top surface of the intermediate block 857 is flush with the top surface of the fixed block 851, the length of the fine adjustment connector 85 is the shortest.

[0051] In another embodiment, the fine adjustment connector 85 between the jack and the top iron assembly is fixedly connected with the corresponding top column. In actual use, the top column block 86 of the short section can be added between the movable block 855 of the fine adjustment connector 85 and the corresponding jack, so as to ensure that the top iron assembly supports the jack.

[0052] In another embodiment, the outer side of the counter-pressure device 82 in the top iron assembly on both sides of the same group of jacking equipment 8 is fixedly connected with the anchor rod 84 through the connecting plate 83, and one end of the anchor rod 84 is anchored to the sliding plate 9 or the bottom of the working pit. One end of the connecting plate 83 is fixedly connected with the counter-pressure device 82, and the other end is sleeved on the anchor rod 84 and fixed. The connecting plate 83 and the anchor rod 84 and the fine adjustment connector 85 between the two laterally adjacent counter-pressure devices 82 connect each counter-pressure device 82 in the same group of jacking equipment 8 into a whole and fix it, so as to ensure the stability and supportability of the top iron assembly, and each component is easy to disassemble and install, and can be repeatedly put into use.

[0053] In another embodiment, as shown in Figure 6 The counter-pressure device 82 includes a counter-pressure pier 821, which is a concrete pier column with a reverse concave shape in cross-section. Two side top rods 822 are arranged on the inner walls of both sides of the counter-pressure pier 821 respectively corresponding to two top columns 81, and a plurality of upper top rods 823 are arranged on the inner top surface of the counter-pressure pier 821 respectively corresponding to two top columns. Each upper top rod 823 is connected with the inner top surface of the counter-pressure pier 821 through a spherical hinge support 824. The side top rod 822 and the upper top rod 823 are telescopic structures.

[0054] The concrete pier column is used as the counter-pressure pier 821 to provide counter-pressure to the connection of the two top columns 81, and the side top rods 822 and the upper top rods 823 are used to press against the corresponding top columns 81 to avoid the connection between the two adjacent top columns 81 from being warped or even jumped out during the jacking process, thus ensuring the stability of the top iron assembly. In the two adjacent top columns, each top column 81 is provided with at least two side top rods 822 and two upper top rods 823 at the top of both sides of the connection to press against the counter-pressure. The side top rods 822 and the upper top rods 823 are telescopic structures, and simple telescopic rods composed of sleeves and screw rods can be used to adapt to top columns 81 of different sizes in consideration of the cost. The upper top rods 823 are connected with the inner top surface of the counter-pressure pier 821 through the ball hinge support 824, and when the top column 81 is a cylindrical column, the ball hinge support 824 is used to make the axis of the upper top rod 823 keep pointing to the center of the top column 81, thus ensuring the pressing force of the upper top rod 823 on the top column 81.

[0055] Although the embodiments of the present application have been disclosed as above, they are not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and additional modifications can be easily realized by those skilled in the art, and thus the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A continuous multi-hole ultra-low frame bridge skew jacking construction method, comprising four-hole frame bridges, the distance between adjacent two-hole frame bridges is a certain distance, characterized in that, The method comprises the following steps: S1, completing overhead reinforcement work of railway line; S2, excavating a working pit on one side of the railway line while performing step S1, and performing a sliding plate and a lubricating isolation layer on the bottom surface of the working pit, and performing a backup pile on the side of the working pit away from the railway line; S3, prefabricating each frame bridge on the lubricating isolation layer, and sequentially arranging a No. 1 frame bridge, a No. 2 frame bridge, a No. 3 frame bridge and a No. 4 frame bridge along the extension direction of the railway line; S4, installing jacking equipment between each frame bridge and the backup pile; S5, first jacking the No. 1 frame bridge and the No. 4 frame bridge on both sides simultaneously through the jacking equipment, then jacking the No. 2 frame bridge and the No. 3 frame bridge in the middle simultaneously after the No. 1 frame bridge and the No. 4 frame bridge are jacked into position; S6, filling and compacting the gaps between each frame bridge and the transition sections where soil collapse occurs on both sides with concrete, and backfilling the upper part of each frame bridge with coarse sand and ballast; S7, removing the jacking equipment and restoring the railway line; In step S4, two groups of jacking equipment are arranged between each frame bridge and the corresponding backup pile, and the two groups of jacking equipment are arranged on both sides of the central axis of the frame bridge; the jacking equipment comprises a plurality of jacks and a top iron assembly arranged between each jack and the backup pile, the axis of the top iron assembly is on the same straight line as the axis of the jack, and is parallel to the jacking path; The top iron assembly comprises a plurality of top columns connected in sequence and centered, and a counter-pressure device is arranged at the connection between adjacent top columns in the same top iron assembly; two adjacent counter-pressure devices in different top iron assemblies are connected through a fine adjustment connecting piece; the fine adjustment connecting piece is arranged between each jack and the corresponding top iron assembly; The fine adjustment connecting piece comprises a fixed block, a movable block and an intermediate block arranged therebetween; the intermediate block is sleeved on a screw rod and is in threaded connection with the screw rod, one end of the screw rod is connected with a driving motor; one end of the intermediate block towards the fixed block is provided with a wedge block with the same height as the intermediate block, the wedge block has a right triangle structure and the inclined surface thereof faces the fixed block, and a slant groove matched with the wedge block is formed in the fixed block; one side of the intermediate block towards the movable block is in vertical sliding connection with the movable block; slotted holes are formed on both sides of the fixed block, and slide rails corresponding to the slotted holes are arranged on both sides of the movable block, and one end of each slide rail extends into the corresponding slotted hole.

2. The continuous multi-span super low-level frame bridge skew jacking construction method according to claim 1, characterized in that, A steel blade corner is arranged on the top of the side of each frame bridge facing the railway line, and in step S5, each frame bridge is first jacked to the position where the steel blade corner cuts into the railway roadbed through the jacking equipment, and then the jacking and the excavation of the frame bridge are alternately performed until the frame bridge is jacked to the predetermined position.

3. The continuous multi-span super low-level frame bridge with skew jacking construction method according to claim 2, characterized in that, In step S5, during each jacking process of the jacking equipment, the axis and the elevation of the frame bridge are observed when the frame bridge advances by a certain jacking distance, and the jacking direction or the elevation of the frame bridge is corrected in time when deviation occurs.

4. The continuous multi-span super low-level frame bridge with skew jacking construction method according to claim 1, characterized in that, The height of the intermediate block is 1 / 2-2 / 3 of the height of the fixed block, and the slant groove is longitudinally arranged in the vertical direction.

5. The continuous multi-span super low-level frame bridge with skew jacking construction method according to claim 1, characterized in that, The fine adjustment connecting piece between the jack and the top iron assembly is fixedly connected with the corresponding top column.

6. The continuous multi-span super low-level frame bridge with skew jacking construction method according to claim 1, characterized in that, The outer sides of the counter-pressure devices in the top iron assemblies on the two sides in the same group of jacking equipment are fixedly connected with anchor rods through connecting plates, one end of the anchor rods being anchored to the slide plates or the bottom of the working pit.

7. The continuous multi-span super low-level frame bridge with skew jacking construction method according to claim 1, characterized in that, The counter-pressure device comprises a counter-pressure pier, which is a concrete pier column with a reverse concave letter shape in cross section, two side jacks being arranged on the inner walls on the two sides of the counter-pressure pier respectively corresponding to two top columns, and a plurality of upper jacks being arranged on the inner top surface of the counter-pressure pier respectively corresponding to the two top columns, each of the upper jacks being connected with the inner top surface of the counter-pressure pier through a spherical hinge support; the side jacks and the upper jacks are telescopic structures.

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