Fabricated structure underneath passing through box culvert of ground road and co-constructed with large-section rectangular tunnel through common plate and construction method

Abstract

The invention provides a fabricated structure with a box culvert underneath penetrating a ground road and co-constructed with a large-section rectangular tunnel in a common-plate mode and a construction method. The whole structure comprises a lower-layer open cut tunnel, a middle-layer water passing box culvert and an upper-layer ground recovery road. All reinforced concrete is of a prefabricated assembly type structure except a box culvert middle partition wall in the water tank culvert, the box culvert middle partition wall is a cast-in-place section and penetrates through the water tank culvert, the open-cut tunnel top common plate structure and a box culvert top plate are connected into a whole, connection is more stable, and the cracking phenomenon caused by uneven settlement is avoided. The bottom of backfill soil in the box culvert abutment back backfill area is plain soil, an upper roadbed is 6% and 8% lime soil, a top layer is a pavement structure layer, a butt strap is laid on the pavement structure layer close to a box culvert bracket, and a pavement layer is arranged on the water box culvert and the butt strap. By adopting the fabricated structure, the construction efficiency is improved, the construction safety risk is reduced, the engineering cost is saved, the safety of a ground road and an open-cut tunnel section and the smoothness of a river are ensured, and the space use is optimized.

Description

Technical Field

[0001] The present invention belongs to the technical field of water conservancy engineering and tunnel engineering, and in particular relates to an assembled structure and a construction method for a box culvert that passes under a ground road and is co-built with a large-section rectangular tunnel. Background Art

[0002] In urban infrastructure construction, box culverts are used to achieve functions such as drainage and water passing, while tunnel construction often focuses on traffic diversion. If traditional box culvert construction encounters tunnel projects, especially large-section rectangular tunnels, the independent construction of the two is likely to cause problems such as unreasonable space utilization, complex construction procedures and mutual interference. With the increasing tension of urban land resources, higher requirements are placed on the efficient use of underground space; realizing the co-construction of box culverts and large-section rectangular tunnels can optimize the force system of underground structures, reduce the impact on ground roads, improve construction efficiency and reduce construction costs. Therefore, how to provide a prefabricated structure and construction method that can be co-constructed with a large-section rectangular tunnel and a box culvert that passes under the ground road has become an urgent problem to be solved in the current tunnel engineering construction. Summary of the invention

[0003] In view of the shortcomings in the prior art, the present invention provides an assembled structure and construction method for a box culvert that passes under a ground road and is built together with a large-section rectangular tunnel. The use of the assembled structure improves construction efficiency, reduces construction safety risks, saves project costs, ensures the safety of ground roads and open-cut tunnel sections and the smooth flow of rivers, and optimizes space utilization.

[0004] The present invention achieves the above technical objectives through the following technical means.

[0005] A prefabricated structure which passes under a ground road and is co-built with a large-section rectangular tunnel, comprises a three-layer structure, namely, an open-cut tunnel at a lower layer, a water-passing box culvert at a middle layer, and a ground recovery road at an upper layer; except for a box culvert middle partition wall in the water-passing box culvert, the remaining structures of the open-cut tunnel and the water-passing box culvert are all prefabricated and assembled reinforced concrete structures; the open-cut tunnel and the water-passing box culvert are connected as a whole by a cast-in-place box culvert middle partition wall to avoid cracking caused by uneven settlement.

[0006] Furthermore, the open-cut tunnel includes an open-cut tunnel floor, tunnel side walls, tunnel center partition walls, tunnel roof, and a common plate structure, all of which are prefabricated and assembled according to two sections, namely the left tunnel line and the right tunnel line; two large beams and one small beam are also arranged in the middle of the open-cut tunnel, and the common plate structure is arranged between the two large beams, and the common plate structure serves as both the top structure of the open-cut tunnel and the floor of the water culvert.

[0007] Furthermore, the water-passing box culvert includes a box culvert top plate, a box culvert partition plate, a revetment and a box culvert middle partition wall which are all prefabricated parts; the box culvert top plate is divided into two sections, and the boundary line thereof is on the same vertical plane as the boundary line of the open-cut tunnel; a vertical embedded steel side waterstop is arranged at the connection between the box culvert top plate and the open-cut tunnel, and the steel side waterstop is installed in cooperation with the arc-shaped grooves and slots on the open-cut tunnel, and is injected with waterproof slurry; a tensioning groove is arranged at the top corner position of the box culvert top plate, and an anchor for cooperating with the steel strand to anchor the segment water-passing box culvert; two strip-shaped corbels are arranged at the upper positions on both sides of the box culvert top plate, respectively, for the installation of the slats in the subsequent ground restoration road; shear keys are arranged on the non-anchoring surface of the box culvert top plate.

[0008] Furthermore, the ground restoration road includes backfill soil, slabs, and paving layers; the bottom of the backfill soil is plain soil, the roadbed above the plain soil is 6% and 8% gray soil, and the top layer is a pavement structure layer; corbels are provided on the top plate of the box culvert, and multiple sets of slabs are laid between the corbels and the pavement structure layer, and paving layers are set on the water-passing box culvert and the slabs to restore the ground road.

[0009] Furthermore, the bottom of the backfill soil is plain soil, the roadbed above it is 60cm thick 6% lime soil and 80cm thick 8% lime soil, and the top layer is 70cm thick pavement structure layer; four groups of 6m long scaffolding are laid near the corbels of the pavement structure layer.

[0010] A construction method of the assembled structure of the box culvert that passes under the ground road and is co-built with the large-section rectangular tunnel includes the following steps: S1. First, construct an earthbag cofferdam outside the structure in the river channel, pump out water, desilt, backfill soil, and dewater the area; then construct bored piles and crown beam support beams, erect steel supports, and excavate the earth; after the foundation pit is excavated and tested, pour the concrete cushion layer; after reaching the required strength, apply the bottom plate and side wall waterproof layer; S2. Each component of the prefabricated structure is transported to the construction site after reaching the concrete design strength; S3, first hoist the tunnel floor, then hoist the tunnel side walls, tunnel partition walls, and finally hoist the tunnel roof; each part is tightly fitted, and high-strength waterproof slurry is injected at the joints; S4. After hoisting two large beams and one small beam to the corresponding positions, hoist the common plate structure, which serves as the middle top plate of the tunnel and the bottom plate of the box culvert; after hoisting and splicing of all components, hoist the box culvert partition to the common plate structure; S5. Lift the top plate of the box culvert to the top of the box culvert partition, match the raised lower end of the box culvert top plate, the buried steel edge water stop belt with the arc groove and slot on the open-cut tunnel, and inject waterproof slurry; S6. An anchor protruding outward is set in the tensioning groove at the top corner of the box culvert top plate, and the steel strand is passed through the prefabricated hole and used in conjunction with the anchor to complete the anchoring of the segmental box culvert; S7, cast-in-place box culvert middle partition wall, thereby connecting the common plate structure and the box culvert top plate into a whole, and then install the box culvert revetment (204) on both sides for diversion; then remove the cofferdam to complete the connection of the river system; S8. Backfill the back of the box culvert: above the tunnel roof near the water box culvert, the plain soil backfill is set in a step shape with a slope of 1:2.0, the roadbed above the steps is set with 6% gray soil backfill, the step near the water box culvert is set with 8% gray soil backfill, the next layer of roadbed is set with 8% gray soil backfill, and the top layer is set as the pavement structure layer; finally, the corbel set on the box culvert roof and the pavement structure layer are transitionally connected with a slab; S9. Set up a paving layer on the water culvert and the slab to restore the ground road.

[0011] The present invention has the following beneficial effects: The present invention adopts an assembled structure, and all reinforced concrete is prefabricated. By splitting the tunnel and the box culvert into sections, it is convenient to move, hoist and adjust the position of each component. The partition wall in the box culvert is a cast-in-place section that runs through the entire tunnel and the box culvert, so that each component is connected as a whole, ensuring the stability of the overall structure. The combination of assembled structure and cast-in-place sections has a simple structure, greatly reduces the casting process, especially reduces the use of a large number of high-support formwork, and significantly improves the quality, efficiency and safety of construction.

[0012] Shear key bite contact is adopted between each segment to avoid sliding displacement between different segments. Tensioning grooves are set at the top of the box culvert corners to penetrate prestressed steel strands, effectively improving the bearing capacity and stability of the concrete structure. A vertical buried steel edge waterstop is set at the connection between the box culvert top plate and the tunnel to prevent river water from leaking into the roadbed.

[0013] The overlapping section of the tunnel and box culvert adopts a common plate structure of the box culvert bottom plate and the tunnel top plate. Compared with the independent design of the two, this method optimizes the use of space and the force system, reduces construction costs, and is energy-saving, environmentally friendly, and economically reasonable.

[0014] The present invention is applicable to box culverts and tunnels that are orthogonal or oblique, and to box culverts and tunnels with single compartments or multiple compartments. The operation process is efficient and convenient, and has high promotion value. In this embodiment, the box culvert is obliquely intersected with the main line of the tunnel. The box culvert partition is set to make the center line of the river straight, avoid local water flow impact or vortex causing damage to components, and ensure the stable state of the water flow. In this embodiment, due to the large scale of the structure, a multi-compartment structure is adopted. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the overlapping common slab structure of the box culvert and the tunnel; Figure 2 This is a schematic diagram of the three-layer structure of open-cut tunnel, water culvert, and ground restoration road; Figure 3 This is a schematic diagram of the open-cut tunnel structure; Figure 4 This is a schematic diagram of the water box culvert structure; Figure 5 Restore the road schematic diagram for the ground; Figure 6 This is a schematic diagram of the box culvert steel side water stop connector, tensioning groove and shear key; Figure 7 This is a schematic diagram of the backfill of the box culvert platform; In the figure: 1-open cut tunnel, 2-water box culvert, 3-ground restoration road, 4-tunnel left line, 5-tunnel right line, 101-tunnel bottom plate, 102-tunnel side wall, 103-tunnel middle partition wall, 104-tunnel top plate, 105-common plate structure, 106-large beam, 107-small beam, 201-box culvert top plate, 202-box culvert partition, 203-box culvert middle partition wall, 204-box culvert revetment, 205-steel side waterstop, 206-tensioning groove, 207-corbel, 208-shear key, 301-backfill soil, 302-planking, 303-pavement layer. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto. The background of the present invention is the Suzhou Changjiang Road South Extension Project, which is located in Wuzhong District, Suzhou City. It starts from the intersection of Changjiang Road and Qizi Road in the north, goes south along Changjiang Road, passes under the Qizi Mountain, and ends at the intersection of Wangshan Road and Nanguandu Road in the south. The total length of the project line is 6.428km; the open-cut tunnel is designed as a single-box double-chamber large-section rectangular structure, passing under the Wangshan River at MLK5+360~MLK5+390. A box culvert needs to be built above the tunnel for drainage. After the box culvert is completed, the earthwork is backfilled to restore the ground road; the geological conditions of the project site are alluvial and residual clay, silty clay, silt, silt sand, silty clay containing crushed stone, and crushed stone soil, with abundant groundwater, and the construction difficulty and risk are relatively large.

[0017] like Figure 1 , 2 As shown, the present invention discloses a prefabricated structure of a box culvert that passes under a ground road and is co-built with a large-section rectangular tunnel. The entire structure is divided into three layers, the lower layer is an open-cut tunnel 1, the middle layer is a water-passing box culvert 2, and the upper layer is a ground recovery road 3. Figures 1 to 4As shown, except for the middle partition wall 203 in the water culvert 2, all reinforced concrete adopts assembled structure and are prefabricated components; the middle partition wall 203 of the box culvert is a cast-in-place segment that runs through the entire water culvert 2, forming the common plate structure 105 and the box culvert top plate 201 into a whole, thereby making the connection between the water culvert 2 and the open-cut tunnel 1 more stable and avoiding cracking caused by uneven settlement.

[0018] like Figure 2 , 3 As shown, the open-cut tunnel 1 includes an open-cut tunnel floor 101, a tunnel side wall 102, a tunnel middle partition wall 103, a tunnel roof 104, and a common plate structure 105, which are prefabricated and assembled according to two sections of the left tunnel line 4 and the right tunnel line 5. Due to the large span, two beams 106 (with a cross-sectional size of 1.40m×4.05m) and a small beam 107 (with a cross-sectional size of 0.8m×1.4m) are arranged in the middle to ensure the stability of the overall structure; a common plate structure 105 is arranged between the two beams 106, which serves as the open-cut tunnel roof and the box culvert floor at the same time.

[0019] like Figure 1 , 2 As shown in Figures 4 and 6, the water culvert 2 includes four parts: a culvert top plate 201, a culvert diaphragm 202, a culvert middle partition wall 203, and a revetment 204. The culvert top plate 201, the culvert diaphragm 202, and the revetment 204 are prefabricated parts, and the culvert middle partition wall 203 is a cast-in-place segment. The culvert top plate 201 is divided into two segments, and the boundary line thereof is on the same vertical plane as the boundary line of the open-cut tunnel 1. A vertical buried steel edge water stop 205 is provided at the connection between the culvert top plate 201 and the open-cut tunnel 1, and a tensioning groove 206 is provided at the top of the culvert corner. Two strip-shaped corbels 207 are provided at the upper positions on both sides of the culvert top plate 201 to facilitate the installation of the slab 302. A shear key 208 is provided on the non-anchoring surface of the culvert top plate 201.

[0020] like Figure 5 As shown, the ground road restoration 3 includes backfill 301 and slabs 302; the back of the box culvert is backfilled, the bottom of the backfill 301 is plain soil, the roadbed above is 60cm thick 6% gray soil and 80cm thick 8% gray soil, and the top layer is 70cm thick pavement structure layer. Above the tunnel top plate 104 5m away from the water culvert 2, the plain soil backfill is set in a step shape with a slope of 1:2.0, the top of the step is 6% gray soil, and the part of the step near the water culvert 2 is 8% gray soil. Four groups of 6m long slabs 302 are laid near the box culvert bracket on the pavement structure layer, and a pavement layer 303 is set on the water culvert 2 and the slabs 302, and then the ground road is restored.

[0021] Reference Figures 1 to 7The present invention provides a method for constructing a prefabricated structure for a box culvert that passes under a ground road and is co-built with a large-section rectangular tunnel, including the following steps: S1. First, construct an earthbag cofferdam outside the structure in the river channel, pump out water, desilt, backfill soil, and dewater the area. Then construct bored piles and crown beam support beams, erect steel supports in time, and excavate the earth. After the foundation pit is excavated and the trench is tested, pour the concrete cushion layer. After reaching the strength, apply the bottom plate and side wall waterproof layer.

[0022] S2. Each component of the prefabricated structure is transported to the construction site after reaching the concrete design strength; S3. First, hoist the bottom plate components of the left tunnel line 4 and the right tunnel line 5 (i.e., tunnel bottom plate 101), then hoist the side walls and middle partition walls of the left tunnel line 4 and the right tunnel line 5 (i.e., tunnel side walls 102 and tunnel middle partition walls 103) respectively, and finally hoist the top plates of the left and right tunnel lines (i.e., tunnel top plate 104); all parts are required to be closely fitted, and high-strength waterproof slurry is injected at the joints; the size and quality of the components must be guaranteed when making prefabricated parts, and care must be taken during transportation to ensure that the shear keys on the non-anchoring surfaces are not damaged.

[0023] S4. After hoisting two large beams 106 and one small beam 107 at corresponding positions, hoist the common plate structure 105, which serves as both the middle top plate of the tunnel and the bottom plate of the box culvert; after hoisting and splicing of all components are completed, hoist the box culvert partition 202 onto the common plate structure 105.

[0024] S5. Lift the box culvert top plate 201 to the top of the box culvert partition 202. The shear key 208 between the two compartment box culvert top plates 201 must be in close contact without damage, so that the two compartment box culvert top plates 201 can mesh with each other during anchoring. Match the raised lower end of the box culvert top plate 201 and the embedded steel side water stop 205 with the arc groove and slot on the open-cut tunnel 1 (i.e., the beam 106), and inject waterproof slurry.

[0025] S6. An outwardly protruding anchor is provided in the tensioning groove 206 at the corner top of the box culvert top plate 201. The steel strand is passed through the prefabricated hole and used in conjunction with the anchor to complete the anchoring of the segmental box culvert.

[0026] S7, cast-in-place box culvert middle partition wall 203, so as to form the common plate structure 105 and the box culvert top plate 201 into a whole, to ensure the stability of the structure; then install the box culvert revetments 204 on both sides for diversion; then remove the cofferdam to complete the connection of the river system.

[0027] S8. Backfill the back of the box culvert platform: use plain soil, 6% and 8% gray soil for backfilling. Specifically, above the tunnel top plate 104 5m away from the water box culvert 2, the plain soil backfill is set in a step shape with a slope of 1:2.0. The top of the step is 60cm thick 6% gray soil, the part of the step close to the water box culvert 2 is 8% gray soil, the next layer of roadbed is 80cm thick 8% gray soil, and the top layer is 70cm thick pavement structure layer; a corbel is provided on the box culvert top plate 201, and a 6m long trestle 302 is used for transition connection between the corbel and the pavement structure layer; a small tamping machine is used for compaction during backfilling to ensure that the compaction degree of the platform back meets the requirements and eliminate the hidden danger of vehicle jumping at the bridge head. The compaction degree should be not less than 96%.

[0028] S9. Lay the box culvert top pavement layer 303 to restore the ground road.

[0029] The application of the technology described in this embodiment has promoted the development and innovation of the construction of prefabricated structures with co-slabs for tunnels and box culverts, and has contributed to the technological progress in related fields.

[0030] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A box culvert that passes under a ground road and is built together with a large-section rectangular tunnel, characterized in that: The invention comprises a three-layer structure, namely, an open-cut tunnel (1) at the lower layer, a water culvert (2) at the middle layer, and a ground recovery road (3) at the upper layer; except for the culvert middle partition wall (203) in the water culvert (2), the remaining structures of the open-cut tunnel (1) and the water culvert (2) are all prefabricated reinforced concrete structures; the open-cut tunnel (1) and the water culvert (2) are connected as a whole by a cast-in-place culvert middle partition wall (203) to avoid cracking caused by uneven settlement.

2. The assembled structure of the box culvert that passes under the ground road and is built together with the large-section rectangular tunnel according to claim 1 is characterized in that: The open-cut tunnel (1) comprises an open-cut tunnel bottom plate (101), a tunnel side wall (102), a tunnel middle partition wall (103), a tunnel top plate (104), and a common plate structure (105), all of which are prefabricated and assembled according to two sections, namely, a left tunnel line (4) and a right tunnel line (5). Two large beams (106) and a small beam (107) are also arranged in the middle of the open-cut tunnel (1), and the common plate structure (105) is arranged between the two large beams (106). The common plate structure (105) serves as both the top structure of the open-cut tunnel (1) and the bottom plate of the water culvert (2).

3. The assembled structure of the box culvert that passes under the ground road and is built together with the large-section rectangular tunnel according to claim 2 is characterized in that: The water-passing box culvert (2) comprises a box culvert top plate (201), a box culvert partition plate (202), a revetment (204), and a box culvert middle partition wall (203) which are all prefabricated parts; the box culvert top plate (201) is divided into two sections, and the boundary line thereof is on the same vertical plane as the boundary line of the open-cut tunnel (1); a vertical embedded steel edge water stop strip (205) is provided at the connection between the box culvert top plate (201) and the open-cut tunnel (1), and the steel edge water stop strip (205) is connected to the arc-shaped water stop strip on the open-cut tunnel (1). The grooves and slots are installed in coordination and are injected with waterproof slurry; a tensioning groove (206) is provided at the top corner of the box culvert top plate (201), and an anchor for cooperating with the steel strand to anchor the segmental water-passing box culvert (2) is provided in the tensioning groove (206); two strip-shaped brackets (207) are respectively provided at the upper positions on both sides of the box culvert top plate (201) for the installation of the slab (302) in the subsequent ground restoration road (3); and a shear key (208) is provided on the non-anchoring surface of the box culvert top plate (201).

4. The assembled structure of the box culvert that passes under the ground road and is built together with the large-section rectangular tunnel according to claim 3 is characterized in that: The ground restoration road (3) comprises backfill soil (301), a slab (302), and a pavement layer (303); the bottom of the backfill soil (301) is plain soil, the roadbed above the plain soil is 6% and 8% gray soil, and the top layer is a pavement structure layer; a corbel is provided on the box culvert top plate (201), a plurality of sets of slabs (302) are laid between the corbel and the pavement structure layer, and a pavement layer (303) is provided on the water box culvert (2) and the slab (302), so as to restore the ground road.

5. The assembled structure of the box culvert that passes under the ground road and is built together with the large-section rectangular tunnel according to claim 4 is characterized in that: The bottom of the backfill soil (301) is plain soil, the roadbed above is 60 cm thick 6% lime soil and 80 cm thick 8% lime soil, and the top layer is a 70 cm thick pavement structure layer; four groups of 6 m long slabs (302) are laid near the corbels of the pavement structure layer.

6. A construction method for a prefabricated structure of a box culvert that passes under a ground road and is co-built with a large-section rectangular tunnel as claimed in claim 4, characterized in that: The process includes the following: S1. First, construct an earthbag cofferdam outside the structure in the river channel, pump out water, desilt, backfill soil, and dewater the area; then construct bored piles and crown beam support beams, erect steel supports, and excavate the earth; after the foundation pit is excavated and tested, pour the concrete cushion layer; after reaching the required strength, apply the bottom plate and side wall waterproof layer; S2. Each component of the prefabricated structure is transported to the construction site after reaching the concrete design strength; S3, first hoist the tunnel floor (101), then hoist the tunnel side walls (102), the tunnel middle partition wall (103), and finally hoist the tunnel roof (104); each part is tightly fitted, and high-strength waterproof slurry is injected at the joints; S4, after hoisting two large beams (106) and one small beam (107) at corresponding positions, hoist the common plate structure (105), which serves as both the middle top plate of the tunnel and the bottom plate of the box culvert; after hoisting and splicing of all components, hoist the box culvert partition (202) onto the common plate structure (105); S5, hoisting the box culvert top plate (201) to the top of the box culvert partition (202), matching the lower end protrusion of the box culvert top plate (201) and the embedded steel edge water stop (205) with the arc-shaped groove and slot on the open-cut tunnel (1), and injecting waterproof slurry; S6. An outwardly protruding anchor is arranged in the tensioning groove (206) at the corner top of the box culvert top plate (201), and the steel strand is passed through the prefabricated hole and used in conjunction with the anchor to complete the anchoring of the segmental box culvert; S7, cast-in-place box culvert middle partition wall (203), thereby connecting the common plate structure (105) and the box culvert top plate (201) into a whole, and then install the box culvert revetments (204) on both sides for diversion; then remove the cofferdam to complete the connection of the river system; S8, backfilling the back of the box culvert: above the tunnel top plate (104) near the water box culvert (2), the plain soil backfill is set in a step shape with a slope of 1:2.0, the roadbed above the step is set to be 60 cm thick and 6% gray soil backfill, the step near the water box culvert (2) is set to be 8% gray soil backfill, the next layer of roadbed is set to be 80 cm thick and 8% gray soil backfill, and the top layer is set to be 70 cm thick road surface structure layer; finally, the bracket set on the box culvert top plate (201) and the road surface structure layer are transitionally connected by a slab (302); S9. A pavement layer (303) is provided on the water culvert (2) and the slab (302) to restore the ground road.

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