A construction method for tunnel opening at the junction of bridge and tunnel

Abstract

The present invention discloses a construction method for a tunnel entrance where a bridge and a tunnel are connected, comprising the following steps: constructing a tunnel entrance platform at the tunnel entrance close to the slope surface; excavating an installation foot groove on the slope surface below the tunnel entrance platform; installing the arch foot plates of the first corrugated steel arch and the second corrugated steel arch in the installation foot groove of the corresponding height; filling the first corrugated steel arch and the second corrugated steel arch with concrete; laying an extension platform plate on the top of each of the first corrugated steel arch and the second corrugated steel arch; assembling a tunnel secondary lining formwork trolley on the extension platform plate and the tunnel entrance platform. The present invention provides a stable and sufficient working surface for the assembly and construction of the tunnel secondary lining formwork trolley by laying an extension platform plate on the top of the corrugated steel arch and docking it with the tunnel entrance platform, effectively solving the construction difficulties caused by the narrow tunnel entrance platform, and avoiding the construction inconvenience and extra engineering workload caused by the traditional solution of assembling the trolley in the tunnel or moving it back to form a tunnel surface.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, and in particular to a construction method for a tunnel opening at a place where a bridge and a tunnel are connected. Background Art

[0002] In modern transportation infrastructure construction, the bridge-tunnel connection structure is a common engineering form, especially in mountainous areas or complex terrain areas. This structure can effectively shorten the route length, reduce the project cost, and improve the continuity and safety of traffic. However, the construction of the bridge-tunnel connection has always been a difficult point in the engineering field, especially at the junction of the tunnel entrance and the bridge pile foundation. Due to the narrow construction access road and the narrow construction platform at the entrance, the tunnel and the bridge pile foundation cannot be constructed simultaneously. Usually, the tunnel is constructed first and then the bridge, which seriously affects the project progress. In addition, tunnel construction requires the assembly of a secondary lining trolley at the entrance. The general length of the trolley is 9 to 15 meters. When the construction platform at the entrance is narrow, there are currently two solutions: one is to assemble the secondary lining trolley in the tunnel, but the space is limited and the assembly operation is difficult; the other is to move the tunnel surface backward, resulting in too high a side slope of the tunnel, which increases a large amount of side slope protection engineering. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a construction method for a tunnel opening at a bridge-tunnel junction.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A construction method for a tunnel entrance where a bridge and a tunnel are connected, comprising the following steps: S1, constructing a tunnel entrance platform at the tunnel entrance close to the slope surface; S2, excavating installation foot grooves on the slope surface below the tunnel entrance platform, wherein a plurality of installation foot grooves are provided along the slope surface, the plurality of installation foot grooves are staggered in the height direction, and the installation foot grooves in the same group are spaced apart in the left-right direction; S3, installing the arch foot plates of the first corrugated steel arch and the second corrugated steel arch in the installation foot grooves of corresponding heights, and the top contours of the first corrugated steel arch and the second corrugated steel arch are flush, and the first corrugated steel arch and the second corrugated steel arch are sequentially arranged in a direction away from the tunnel entrance platform; S4, filling the first corrugated steel arch and the second corrugated steel arch with concrete; S5, An extension platform plate is laid on the top of each first corrugated steel arch and the second corrugated steel arch to connect with the tunnel entrance platform; S6, assemble the tunnel second lining formwork trolley on the extension platform plate and the tunnel entrance platform, and the tunnel second lining formwork trolley enters the tunnel for construction and detaches from the extension platform plate; S7, remove the second corrugated steel arch and the corresponding extension platform plate to retain the first corrugated steel arch and the corresponding extension platform plate close to the tunnel entrance platform, and expose the concrete blocks cast in the second corrugated steel arch; S8, construction is carried out on the exposed concrete blocks to form a bridge pile foundation; S9, remove the first corrugated steel arch and the corresponding extension platform plate, and fill the pit formed by the removal of the first corrugated steel arch and the corresponding extension platform plate.

[0006] Furthermore, step S1 also includes: constructing a pile foundation construction hole on the slope surface corresponding to the projection area of ​​the second corrugated steel arch; step S3 specifically includes: S31, installing the arch foot plate of the first corrugated steel arch in the installation foot groove of the corresponding height; S32, inserting the casing into the pile foundation construction hole, and installing the pile foundation platform plate on the upper end of the casing; S33, installing the second corrugated steel arches in sequence, and the pile foundation platform plate is connected and fixed to the corresponding second corrugated steel arch above, and the pile foundation platform plate close to the first corrugated steel arch is provided with a side baffle on the side close to the first corrugated steel arch to prevent the concrete in the first corrugated steel arch from entering the space above the pile foundation platform plate.

[0007] Furthermore, the front and rear ends of the first corrugated steel arch and the second corrugated steel arch are provided with outwardly protruding connecting plates, and the connecting plates are provided with first connecting holes; two adjacent first corrugated steel arches or two adjacent second corrugated steel arches or adjacent first corrugated steel arches and second corrugated steel arches are aligned through the first connecting holes on the connecting plates on the corresponding sides and fasteners are installed to achieve splicing.

[0008] Furthermore, the bottom of the extended platform plate is detachably connected to a base plate, and the front and rear sides of the base plate are provided with a first side plate protruding upward, and the first side plate is provided with a second connecting hole; after step S33, it also includes: S34, the base plate is embedded between the connecting plates at both ends of the first corrugated steel arch and the second corrugated steel arch, and the first connecting holes of the two adjacent connecting plates are aligned with the second connecting holes of the first side plates on the two base plates on both sides, and fasteners are installed to achieve the connection and fixation of the adjacent first corrugated steel arch and the second corrugated steel arch and the base plates on the first corrugated steel arch and the second corrugated steel arch; S35, the extended platform plate is installed on the corresponding base plate through detachable fasteners.

[0009] Furthermore, the upper end of the concrete block has a pile foundation construction platform surface formed corresponding to the bottom surface of the pile foundation platform plate to serve as a construction platform for pile foundation construction.

[0010] Furthermore, the front and rear ends of the second corrugated steel arch are provided with inner connecting arc plates protruding inwardly, and the front and rear sides of the pile foundation platform plate are provided with side connecting parts for fitting and connecting with the inner connecting arc plates.

[0011] Furthermore, a support rod is provided at the bottom of the middle portion of the base plate, and the bottom of the support rod is in contact with the arch foot plate.

[0012] Furthermore, an embedding groove is provided on the outer bottom of the slope surface corresponding to the outermost second corrugated steel arch; before step S4, it also includes: embedding the bottom of the end template into the embedding groove, the end template is provided with a third connecting hole, and the third connecting hole is aligned with the first connecting hole on the corresponding side of the outermost second corrugated steel arch and installing fasteners.

[0013] Furthermore, connecting strips are provided on the left and right sides of the bottom of the extended platform plate, and the left and right sides of the base plate are provided with second side panels protruding upwards. The connecting strips are embedded in the space enclosed by the first side panel and the second side panel, and the connecting strips and the second side panel are provided with corresponding holes for connection and fixation by fasteners.

[0014] Furthermore, the arch foot plate is provided with an anchor hole, an anchor rod is passed through the anchor hole, and the anchor rod is inserted into the soil layer of the slope surface.

[0015] The present invention has the following beneficial effects:

[0016] By laying an extended platform plate on the top of the corrugated steel arch and docking it with the tunnel entrance platform, a stable and sufficient working surface is provided for the assembly and construction of the tunnel secondary lining formwork trolley, effectively solving the construction difficulties caused by the narrow tunnel entrance platform, and avoiding the construction inconvenience and additional engineering workload caused by the traditional solution of assembling the trolley in the tunnel or moving it back to form the tunnel surface; when the tunnel secondary lining formwork trolley is constructed and enters the tunnel for construction, in order to facilitate the subsequent pile foundation construction, the second corrugated steel arch and the extended platform plate thereon will be removed and the first corrugated steel arch and the extended platform plate thereon will be retained, which will ensure that there is enough space at the tunnel entrance for the construction of the tunnel portal without affecting the subsequent pile foundation construction. The subsequent pile foundation and tunnel entrance can be constructed at the same time to ensure construction efficiency; by filling concrete in the corrugated steel arch, the supporting strength of the corrugated steel arch is guaranteed, and secondly, filling concrete in the corrugated steel arch can provide counter pressure on the slope surface to ensure the stability of the slope below the entrance.

[0017] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 It is a partial flow chart of an embodiment of the present invention;

[0020] Figure 2 is another partial flow chart of an embodiment of the present invention;

[0021] Figure 3 is a detailed step flow diagram of step S3 of the present invention;

[0022] Figure 4 It is a structural schematic diagram of the present invention during the construction process;

[0023] Figure 5 It is a schematic diagram of slope construction of the present invention;

[0024] Figure 6 It is a schematic diagram of the connection structure of the first corrugated steel arch, the extended platform plate, the second corrugated steel arch, the casing and the pile foundation platform plate;

[0025] Figure 7 It is a schematic diagram of the connection structure between the extended platform plate and the base plate;

[0026] Figure 8 It is a schematic diagram of the exploded structure of the first corrugated steel arch, the second corrugated steel arch and the pile foundation platform plate;

[0027] Fig. 9 It is a cross-sectional view of a state during the construction process;

[0028] Fig.10 It is a cross-sectional view of another state during the construction process.

[0029] Legend:

[0030] Slope 100, bridge pile foundation 101, bridge abutment 102, bridge slab 103, tunnel entrance platform 110, installation foot groove 111, pile foundation construction hole 112, embedded groove 120;

[0031] A first corrugated steel arch 200, a concrete block 201, a pile foundation construction platform surface 202, a second corrugated steel arch 210, an arch foot plate 220, an anchor hole 221, a connecting plate 230, a first connecting hole 231, and an inner connecting arc plate 240;

[0032] The extended platform plate 300, the base plate 310, the support rod 311, the first side plate 320, the second connection hole 321, the connection strip 330, and the second side plate 340;

[0033] Casing 400;

[0034] Pile foundation platform plate 500, side connection part 510, side baffle plate 520;

[0035] End template 600. DETAILED DESCRIPTION

[0036] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0039] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0040] Reference Figure 1 and Figure 2 A preferred embodiment of the present invention provides a method for constructing a tunnel entrance at a bridge-tunnel junction, comprising steps S1, S2, S3, S4, S5, S6, S7, S8 and S9.

[0041] S1, constructing a tunnel entrance platform 110 at the tunnel entrance close to the slope 100.

[0042] S2, excavating installation foot grooves 111 on the slope 100 below the tunnel entrance platform 110, wherein the installation foot grooves 111 are provided in multiple groups along the slope 100, and the multiple groups of installation foot grooves 111 are staggered in the height direction, that is, the multiple groups of installation foot grooves 111 gradually change in height with the inclination of the slope. The installation foot grooves 111 of the same group are arranged at intervals in the left-right direction, which is the width direction of the tunnel entrance.

[0043] S3, the arch foot plates 220 of the first corrugated steel arch 200 and the second corrugated steel arch 210 are installed in the installation foot groove 111 of the corresponding height. It can be understood that the arch foot plates 220 are arranged at the bottom of the left and right sides of the first corrugated steel arch 200 and the second corrugated steel arch 210, and the arch foot plates 220 are placed in the installation foot groove 111 and supported by the bottom wall of the installation foot groove 111, so as to realize the support of the first corrugated steel arch 200 and the second corrugated steel arch 210. And the top profiles of the first corrugated steel arch 200 and the second corrugated steel arch 210 are flush, and the first corrugated steel arch 200 and the second corrugated steel arch 210 are arranged in sequence in the direction away from the tunnel entrance platform 110. It can be understood that in order to reduce the weight of a single component during installation, in some embodiments, the first corrugated steel arch 200 and the second corrugated steel arch 210 can also be arranged to be spliced ​​by multiple sections of corrugated plates.

[0044] S4, concrete is filled in the first corrugated steel arch 200 and the second corrugated steel arch 210. It is understood that the first corrugated steel arch 200 and the second corrugated steel arch 210 are both provided with grouting ports to facilitate the injection of concrete. It is understood that part of the concrete will be filled into the mounting foot groove 111 located inside the first corrugated steel arch 200 and the second corrugated steel arch 210, and the concrete filled into the mounting foot groove 111 can improve the stability of the entire concrete structure.

[0045] S5, an extension platform plate 300 is laid on the top of each first corrugated steel arch 200 and the second corrugated steel arch 210 to dock with the tunnel entrance platform 110. Adjacent extension platform plates 300 are closely arranged together, and the extension platform plate 300 close to the tunnel entrance platform 110 docks with the tunnel entrance platform 110, thereby achieving the extension and expansion of the construction platform. Fig. 9 Status shown.

[0046] S6, assembling the tunnel secondary lining formwork trolley on the extension platform plate 300 and the tunnel entrance platform 110, and the tunnel secondary lining formwork trolley enters the tunnel construction and detaches from the extension platform plate 300.

[0047] S7, dismantle the second corrugated steel arch 210 and the corresponding extended platform plate 300 to retain the first corrugated steel arch 200 and the corresponding extended platform plate 300 near the tunnel entrance platform 110, and expose the concrete block 201 cast in the second corrugated steel arch 210. The retained first corrugated steel arch 200 and the corresponding extended platform plate 300 can be used as an extended platform for tunnel portal construction, as an open hole and side slope construction platform, to expand the size of the construction platform and facilitate construction.

[0048] S8, construction is performed on the exposed concrete block 201 to form a bridge pile foundation 101, so as to achieve Fig.10 The bridge pile foundation 101 is used to support the abutment 102 , and the abutment 102 can support the bridge slab 103 .

[0049] S9, remove the first corrugated steel arch 200 and the corresponding extended platform plate 300, and fill the pit formed by removing the first corrugated steel arch 200 and the corresponding extended platform plate 300, that is, after removing the first corrugated steel arch 200 and the corresponding extended platform plate 300, the concrete structure cast in the first corrugated steel arch 200 will be exposed, and the concrete structure has a fault difference with the tunnel entrance platform 110, which needs to be filled, repaired and leveled. Of course, when filling, the gap with the abutment can also be filled together.

[0050] The present invention provides a construction method for a tunnel entrance where a bridge and a tunnel are connected. By laying an extended platform plate 300 on the top of a corrugated steel arch and docking it with the tunnel entrance platform 110, a stable and sufficient working surface is provided for the assembly and construction of a tunnel secondary lining formwork trolley, which effectively solves the construction difficulties caused by the narrow tunnel entrance platform and avoids the construction inconvenience and additional engineering workload caused by the traditional solution of assembling a trolley in the tunnel or moving it back to form a tunnel surface. When the tunnel secondary lining formwork trolley is constructed and enters the tunnel for construction, in order to facilitate the subsequent pile foundation construction, the second corrugated steel arch 210 and the extended platform plate 300 thereon are removed and the first corrugated steel arch 200 and the extended platform plate 300 thereon are retained. While not affecting the subsequent pile foundation construction, it is also ensured that the tunnel entrance has enough space for the construction of the tunnel entrance. The subsequent pile foundation and the tunnel entrance can be constructed at the same time to ensure construction efficiency. By filling concrete in the corrugated steel arch, the supporting strength of the corrugated steel arch is ensured, and secondly, by filling concrete in the corrugated steel arch, a back pressure can be provided to the slope surface of the slope to ensure the stability of the slope below the entrance.

[0051] In some embodiments of the present invention, reference Figure 5 Step S1 also includes: constructing a pile foundation construction hole 112 on the slope surface 100 corresponding to the projection area of ​​the second corrugated steel arch 210 .

[0052] Reference Figure 3 , step S3 specifically includes steps S31, S32 and S33.

[0053] S31, installing the arch foot plate 220 of the first corrugated steel arch 200 in the installation foot groove 111 of the corresponding height.

[0054] S32, insert the casing 400 into the pile foundation construction hole 112 to prevent concrete from entering the pile foundation construction hole 112 and affecting the subsequent pile foundation construction. Install the pile foundation platform plate 500 on the upper end of the casing 400. The pile foundation platform plate 500 and the casing 400 can be connected by fasteners. The casing 400 can be made of multiple sections. The casing 400 needs to be removed later. The casing 400 can not only prevent concrete from entering the pile foundation construction hole 112, but also serve as a protective structure when constructing the pile foundation in the pile foundation construction hole 112 to prevent the soil layer at the hole entrance from collapsing and falling into the hole bottom. Fig. 9 As shown, the initial pile foundation construction hole 112 is usually not deep and is used for inserting and positioning the casing 400. After step S7 is completed, as shown in FIG. Fig.10 As shown, it is necessary to continue digging the pile foundation construction hole 112 downward until a stable soil layer structure is reached, so that the support at the bottom of the bridge pile foundation 101 is stable. Of course, when the casing 400 is inserted into the pile foundation construction hole 112, an auxiliary support can be used to stabilize the posture, and the bottom of the pile foundation platform 500 can also be supported by an auxiliary support frame to avoid instability caused by too many suspended parts.

[0055] S33, the second corrugated steel arch 210 is installed in sequence, and the pile foundation platform plate 500 is connected and fixed to the corresponding second corrugated steel arch 210 above, and the pile foundation platform plate 500 close to the first corrugated steel arch 200 is provided with a side baffle 520 on the side close to the first corrugated steel arch 200 to prevent the concrete in the first corrugated steel arch 200 from entering the space above the pile foundation platform plate 500. It can be understood that the pouring space of the first corrugated steel arch 200 is not connected to the pouring space below the pile foundation platform plate 500, and when pouring, the concrete at the first corrugated steel arch 200 can be poured first.

[0056] The pile foundation platform plate 500 may be provided in plurality, the number of which corresponds to the number of the second corrugated steel arches 210, so that the pile foundation platform plate 500 may be assembled according to the actual number of the second corrugated steel arches 210. Fig.10 The upper end of the concrete block 201 has a pile foundation construction platform surface 202 formed corresponding to the bottom surface of the pile foundation platform plate 500, so as to serve as a construction platform for pile foundation construction. The pile foundation construction platform surface 202 can be formed directly without the need for subsequent excessive construction. Fig.10 As shown, the pile foundation construction platform surface 202 can also be used as a supporting surface at the bottom of the abutment 102 in the future to improve the installation stability of the abutment 102. Of course, the pile foundation platform plate 500 can also be a larger plate-like structure, and only one structure is required.

[0057] Of course, in other embodiments, the pile foundation platform plate 500 and the pile foundation construction hole 112 may not be provided. First, an arched concrete block is formed in the first corrugated steel arch 200, and then a construction platform is processed on the arched concrete block to serve as a construction platform for pile foundation construction, and then the pile foundation construction hole is excavated on the construction platform until the pile foundation construction hole is dug deep into the soil layer. However, compared with directly using the pile foundation platform plate 500 and the casing 400 as the foundation for pouring, such construction can directly form the pile foundation construction platform surface 202, and there is no need to remove the concrete layer to form the pile foundation construction hole 112.

[0058] Reference Figure 6 and Figure 8In some embodiments of the present invention, both the front and rear ends of the first corrugated steel arch 200 and the second corrugated steel arch 210 are provided with a connecting plate 230 protruding outward, and the connecting plate 230 is provided with a first connecting hole 231; two adjacent first corrugated steel arches 200 or two adjacent second corrugated steel arches 210 or adjacent first corrugated steel arches 200 and second corrugated steel arches 210 are aligned through the first connecting holes 231 on the connecting plates 230 on the corresponding sides and fasteners are installed to achieve splicing. That is, the first corrugated steel arch 200 and the second corrugated steel arch 210 are arranged in sequence, and the number of the first corrugated steel arch 200 and the second corrugated steel arch 210 can be one or more, then it is possible that two adjacent first corrugated steel arches 200 are spliced, two adjacent second corrugated steel arches 210 are spliced, and the adjacent first corrugated steel arch 200 and second corrugated steel arch 210 are spliced, and the splicing is achieved by bonding the connecting plates 230 at the ends and installing fasteners on the first connecting holes 231 to achieve connection and fixation. Refer to Figure 4 and Figure 5 In this embodiment, three groups of mounting foot grooves 111 are provided, one group of mounting foot grooves 111 is provided with four, and one group of mounting foot grooves 111 is symmetrically arranged to correspond to two bidirectional tunnels. Thus, the first corrugated steel arch 200 and the second corrugated steel arch 210 are also symmetrically arranged to achieve symmetrical support. The first corrugated steel arch 200 corresponds to a group of mounting foot grooves 111 at the highest point, and the two groups of mounting foot grooves 111 below are for the installation of the second corrugated steel arch 210. There will be splicing of the first corrugated steel arch 200 and the second corrugated steel arch 210 and splicing of the two second corrugated steel arches 210. The splicing is achieved by attaching the connecting plates 230 on the corresponding sides and installing fasteners on the aligned first connecting holes 231 to achieve splicing and fixing.

[0059] Reference Figure 6 and Figure 7 In some embodiments of the present invention, the bottom of the extension platform plate 300 is detachably connected to a base plate 310, and the front and rear sides of the base plate 310 are provided with a first side plate 320 protruding upward, and the first side plate 320 is provided with a second connection hole 321.

[0060] Reference Figure 3 , after step S33, it also includes steps S34 and S35.

[0061] S34, the base plate 310 is embedded between the connecting plates 230 at both ends of the first corrugated steel arch 200 and the second corrugated steel arch 210, that is, the connecting plates 230 at both ends of each first corrugated steel arch 200 or the second corrugated steel arch 210 are embedded in the base plate 310 before, so as to be installed with the corresponding extended platform plate 300. The first connecting holes 231 of the two adjacent connecting plates 230 are aligned with the second connecting holes 321 of the first side plates 320 on the two base plates 310 on both sides, and fasteners are installed to realize the connection and fixation of the adjacent first corrugated steel arch 200 and the second corrugated steel arch 210 and the base plates 310 on the first corrugated steel arch 200 and the second corrugated steel arch 210. That is, the two connecting plates 230 on the splicing sides of two adjacent corrugated steel arches are fitted together, and there is a base plate 310 on each of the front and rear sides of the two fitted connecting plates 230. The holes on the rear first side plate 320 of the front base plate 310, the two connecting plates 230 and the front first side plate 320 of the rear base plate 310 are aligned and fasteners are installed to realize the splicing of the corrugated steel arches, while also realizing the connection and fixation of the base plate 310. The connection position is located outside the corrugated steel arch for easy installation and disassembly. The fasteners can be bolts and nuts.

[0062] S35, installing the extension platform plate 300 on the corresponding base plate 310 through a detachable fastener.

[0063] Reference Figure 8 In some embodiments of the present invention, the front and rear ends of the second corrugated steel arch 210 are provided with inner connecting arc plates 240 protruding inwardly, and the inner connecting arc plates 240 are provided at the top area of ​​the second corrugated steel arch 210. The front and rear sides of the pile foundation platform plate 500 are provided with side connecting parts 510 for fitting and connecting with the inner connecting arc plates 240. The side connecting parts 510 and the inner connecting arc plates 240 are provided with corresponding holes to be connected and fixed by fasteners. The bottom of the inner connecting arc plates 240 can be just a cross bar to eliminate the gap between the front and rear pile foundation platform plates 500, and can also improve the structural strength of the second corrugated steel arch 210.

[0064] Reference Figure 6 and Figure 7 In some embodiments of the present invention, a support rod 311 is provided at the bottom of the middle part of the base plate 310, and the bottom of the support rod 311 contacts the arch foot plate 220, thereby providing auxiliary support for the suspended position in the middle part of the base plate 310 and improving the support stability.

[0065] Reference Fig. 9In a further embodiment of the present invention, a groove 120 is provided on the outer bottom of the slope surface 100 corresponding to the outermost second corrugated steel arch 210. Before step S4, it also includes: embedding the bottom of the end template 600 into the groove 120, and the end template 600 is provided with a third connection hole, and the third connection hole is aligned with the first connection hole 231 on the corresponding side of the outermost second corrugated steel arch 210 and fasteners are installed, so as to achieve the connection and fixation of the end template 600. The embedding of the bottom of the end template 600 into the groove 120 can limit the bottom of the end template 600. Of course, an auxiliary support frame can also be set up on the end template 600 to resist the concrete pressure. Of course, when dismantling the second corrugated steel arch 210, the end template 600 also needs to be dismantled together.

[0066] Reference Figure 7 In a further embodiment of the present invention, the bottom left and right sides of the extension platform plate 300 are provided with connecting strips 330, and the left and right sides of the base plate 310 are provided with second side panels 340 protruding upwards. The connecting strips 330 are embedded in the space enclosed by the first side panel 320 and the second side panel 340, and the connecting strips 330 and the second side panel 340 are provided with corresponding holes to be connected and fixed by fasteners. Specifically, nuts can be welded on the inner side of the connecting strips 330 and holes corresponding to the nuts are provided, and the second side panel 340 is provided with holes corresponding to the holes and bolts are inserted to connect with nuts to achieve connection and fixation.

[0067] Reference Figure 6 In some embodiments of the present invention, the arch foot plate 220 is provided with an anchor hole 221 , and an anchor rod is passed through the anchor hole 221 . The anchor rod is inserted into the soil layer of the slope to lock the arch foot plate 220 .

[0068] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, 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 construction method for a tunnel opening where a bridge and a tunnel meet, characterized in that: The steps include: S1, constructing a tunnel entrance platform (110) at the tunnel entrance close to the slope (100); S2, excavating installation foot grooves (111) on the slope surface (100) below the tunnel entrance platform (110), wherein a plurality of installation foot grooves (111) are provided along the slope surface (100), the plurality of installation foot grooves (111) are staggered in the height direction, and the installation foot grooves (111) in the same group are spaced apart in the left-right direction; S3, installing the arch foot plates (220) of the first corrugated steel arch (200) and the second corrugated steel arch (210) in the installation foot grooves (111) of corresponding heights, and the top profiles of the first corrugated steel arch (200) and the second corrugated steel arch (210) are flush, and the first corrugated steel arch (200) and the second corrugated steel arch (210) are arranged in sequence in a direction away from the tunnel entrance platform (110); S4, filling the first corrugated steel arch (200) and the second corrugated steel arch (210) with concrete; S5, laying an extended platform plate (300) on the top of each first corrugated steel arch (200) and the second corrugated steel arch (210) to dock with the tunnel entrance platform (110); S6, assembling a tunnel secondary lining formwork trolley on the extension platform plate (300) and the tunnel entrance platform (110), and the tunnel secondary lining formwork trolley enters the tunnel construction and detaches from the extension platform plate (300); S7, removing the second corrugated steel arch (210) and the corresponding extended platform plate (300) to retain the first corrugated steel arch (200) and the corresponding extended platform plate (300) near the tunnel entrance platform (110), and exposing the concrete block (201) cast in the second corrugated steel arch (210); S8, performing construction on the exposed concrete block (201) to form a bridge pile foundation (101); S9, removing the first corrugated steel arch (200) and the corresponding extended platform plate (300), and filling the pit formed by removing the first corrugated steel arch (200) and the corresponding extended platform plate (300).

2. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 1 is characterized in that: Step S1 also includes: constructing a pile foundation construction hole (112) on the slope surface (100) corresponding to the projection area of ​​the second corrugated steel arch (210); Step S3 specifically includes: S31, installing the arch foot plate (220) of the first corrugated steel arch (200) in the installation foot groove (111) of the corresponding height; S32, inserting the casing (400) into the pile foundation construction hole (112), and installing the pile foundation platform plate (500) on the upper end of the casing (400); S33, the second corrugated steel arches (210) are installed in sequence, and the pile foundation platform plate (500) is connected and fixed to the corresponding second corrugated steel arch (210) above, and a side baffle plate (520) is provided on the side of the pile foundation platform plate (500) close to the first corrugated steel arch (200) to prevent concrete in the first corrugated steel arch (200) from entering the space above the pile foundation platform plate (500).

3. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 2 is characterized in that: The front and rear ends of the first corrugated steel arch (200) and the second corrugated steel arch (210) are each provided with a connecting plate (230) protruding outwards, and the connecting plate (230) is provided with a first connecting hole (231); two adjacent first corrugated steel arches (200) or two adjacent second corrugated steel arches (210) or an adjacent first corrugated steel arch (200) and a second corrugated steel arch (210) are aligned through the first connecting holes (231) on the connecting plates (230) on the corresponding sides and fasteners are installed to achieve splicing.

4. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 3 is characterized in that: The bottom of the extension platform plate (300) is detachably connected to a base plate (310), and the front and rear sides of the base plate (310) are provided with a first side plate (320) protruding upwards, and the first side plate (320) is provided with a second connection hole (321); After step S33, the method further includes: S34, a base plate (310) is embedded between the connecting plates (230) at both ends of the first corrugated steel arch (200) and the second corrugated steel arch (210), the first connecting holes (231) of the two adjacent connecting plates (230) are aligned with the second connecting holes (321) of the first side plates (320) on the two base plates (310) on both sides, and fasteners are installed, so as to realize the connection and fixation of the adjacent first corrugated steel arch (200) and the second corrugated steel arch (210) and the base plates (310) on the first corrugated steel arch (200) and the second corrugated steel arch (210); S35, installing the extended platform plate (300) on the corresponding base plate (310) via a detachable fastener.

5. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 2, characterized in that: The upper end of the concrete block (201) is provided with a pile foundation construction platform surface (202) formed corresponding to the bottom surface of the pile foundation platform plate (500) to serve as a construction platform for pile foundation construction.

6. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 2, characterized in that: The front and rear ends of the second corrugated steel arch (210) are provided with inner connecting arc plates (240) protruding inwardly, and the front and rear sides of the pile foundation platform plate (500) are provided with side connecting parts (510) for fitting and connecting with the inner connecting arc plates (240).

7. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 4, characterized in that: A support rod (311) is provided at the bottom of the middle portion of the base plate (310), and the bottom of the support rod (311) is in contact with the arch foot plate (220).

8. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 3 is characterized in that: An embedding groove (120) is provided on the slope surface (100) at the outer bottom portion corresponding to the outermost second corrugated steel arch (210); Before step S4, the method further includes: embedding the bottom of the end template (600) into the embedding groove (120), wherein the end template (600) is provided with a third connection hole, and the third connection hole is aligned with the first connection hole (231) on the corresponding side of the outermost second corrugated steel arch (210), and fasteners are installed.

9. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 4, characterized in that: The bottom left and right sides of the extension platform plate (300) are provided with connecting strips (330), and the left and right sides of the base plate (310) are provided with second side panels (340) protruding upwards. The connecting strips (330) are embedded in the space enclosed by the first side panel (320) and the second side panel (340), and the connecting strips (330) and the second side panel (340) are provided with corresponding holes so as to be connected and fixed by fasteners.

10. The construction method of the tunnel opening at the junction of a bridge and a tunnel according to claim 1, characterized in that: The arch foot plate (220) is provided with an anchor hole (221), and an anchor rod is passed through the anchor hole (221), and the anchor rod is inserted into the soil layer of the slope surface.

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