Urban bridge bridgehead transition slab structure and construction method thereof

Abstract

An urban bridge bridgehead transition slab structure comprises a bridge abutment which is divided into an abutment body, an abutment cap and a back wall from bottom to top, shockproof stop blocks are arranged above the two sides of the abutment cap, and the back wall is located at the rear end of the abutment cap; the retaining wall is arranged adjacent to the rear side of the abutment, the longitudinal section is L-shaped, the bottom end extends towards the rear roadbed, and the top end is rigidly connected with the back wall; the supporting plate is horizontally arranged behind the back wall, the front end is rigidly connected with the top end of the retaining wall, and compaction piles are arranged on the lower portion of the rear end; the bridgehead transition slab is horizontally arranged above the supporting plate, the front end is connected with the sinking platform at the rear end of the top of the back wall, and gravel sand is filled between the bottom and the supporting plate. Through cooperative cooperation of the L-shaped retaining wall, the supporting plate and the compaction piles, bridge end transition slab settlement caused by roadbed and foundation settlement can be effectively reduced, meanwhile, effective supporting can be provided for the bridge end transition slab, deformation and bending of the bridge end transition slab are prevented, and the risk of bump at the bridge end is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, specifically to an approach slab structure for urban bridges and its construction method. Background Technology

[0002] In urban bridge construction, approach slab settlement is an unavoidable problem. Existing technologies generally use approach slabs to mitigate and transition the longitudinal abrupt change in road surface caused by excessive differential settlement at the connection between the abutment and the embankment behind the abutment. By controlling the longitudinal slope change of the road surface within acceptable limits, the aim is to alleviate or even eliminate approach slab settlement.

[0003] However, whether it is laying geocells on the back of the abutment, increasing the density of the roadbed fill, or adding other supports, it can only reduce the impact of partial settlement from the roadbed. It does not have a significant effect on the bridge approach slab problem, which is mainly caused by foundation settlement.

[0004] This application aims to solve the problem of bridge approach slab settlement at its source. Summary of the Invention

[0005] To address the technical problems existing in the background art, the present invention provides an approach slab structure for urban bridges and its construction method.

[0006] The technical solution of this invention is as follows: A bridge abutment slab structure for urban bridges, comprising: The bridge abutment is divided into the abutment body, abutment cap, and back wall from bottom to top. Anti-vibration blocks are installed on the upper sides of the abutment cap, and the back wall is located at the rear of the abutment cap. The retaining wall is set up adjacent to the rear side of the bridge abutment. Its longitudinal section is L-shaped, with the bottom end extending towards the roadbed behind it and the top end rigidly connected to the back wall. The support plate is horizontally set behind the back wall, with its front end rigidly connected to the top of the retaining wall and its rear end equipped with compaction piles. The bridge approach slab is horizontally set above the support slab, with its front end connected to the rear end of the back wall and its bottom filled with gravel and sand between it and the support slab.

[0007] The abutments, retaining walls, support slabs, and approach slabs are all reinforced concrete structures.

[0008] The platform can be constructed using a ribbed or cylindrical structure, with side walls on both sides of the platform back.

[0009] The design of the L-shaped retaining wall in this application has two advantages. First, the opening is filled with compacted soil to support the support plate. After the support plate is rigidly connected to the top of the retaining wall, the soil inside is in a semi-closed state with poor fluidity, which effectively reduces the impact of roadbed settlement. Second, the rigid connection between the top of the retaining wall and the back wall can reduce the corresponding settlement of the retaining wall due to foundation settlement, thus effectively reducing the impact of foundation settlement.

[0010] Moreover, the design of the compaction piles at the rear end of the support plate further improves the compaction degree at the rear end of the support plate. Since the backfill soil at the location of the compaction piles is located above the fixed retaining wall base plate and has poor fluidity, it can effectively reduce the settlement of the compaction piles themselves, thereby better supporting the support plate.

[0011] The support plate of this invention is located entirely below the bridge abutment slab, with only crushed stone and sand between it and the bridge abutment slab. The crushed stone and sand itself will not cause significant settlement. As the main load-bearing component, one end of the support plate is rigidly connected to the retaining wall and will not be displaced. The other end is located above the compaction piles. The compaction piles have reduced the impact of settlement through the special design of the retaining wall. Therefore, the support plate of this invention can effectively support the bridge abutment slab and reduce the phenomenon of bridge abutment slab jumping caused by its deformation.

[0012] Moreover, the retaining wall of this invention can be backfilled with a large amount of soil, which reduces costs compared to the existing technology of backfilling a large amount of crushed stone and sand to reduce sedimentation.

[0013] This invention also provides a construction method for bridge abutment slabs in urban bridges, which uses the above-mentioned bridge abutment slab structure and specifically includes the following steps: S1, Construction of the bridge abutment body; S2. Construct a retaining wall on the foundation behind the bridge abutment and rigidly connect the top of the retaining wall to the back wall. S3. Backfill soil between the retaining wall and the roadbed in layers and compact each layer until the height reaches the top of the retaining wall. S4. Based on the length of the support plate, construct compaction piles along the width of the bridge at a predetermined distance behind the top of the retaining wall. S5. Hoist the support plate so that its front end rests on the top of the retaining wall and its rear end rests on the compaction piles, and then rigidly connect the front end of the support plate to the top of the retaining wall. S6. Backfill soil in layers between the rear of the support plate and the roadbed, and compact each layer. S7. Fill the space above the support plate with crushed stone and sand, and compact it. S8. Lay bridge approach slabs on top of the gravel and sand, and rigidly connect the front end of the slabs to the rear end of the back wall.

[0014] Furthermore, the rear end face of the back wall is a smooth vertical surface, and the top height of the retaining wall is higher than 1 / 3 of the height of the back wall, leaving space for the connection between the two.

[0015] The width of the support plate extending backward is greater than the width of the bottom edge of the retaining wall, which increases the support effect on the bridge approach slab.

[0016] The support plate, retaining wall and bridge approach slab are all prefabricated components, which can improve on-site construction efficiency.

[0017] In step S4, the distance between the compaction pile and the front face of the retaining wall is matched with the width dimension of the support plate extending backward.

[0018] Furthermore, the compaction piles are arranged in one or more rows, and at least one row has its vertical projection located on the bottom edge of the retaining wall. This is a key design feature of the present invention, which can effectively prevent the compaction piles from settling along with the soil layer.

[0019] The width of the bridge approach slab extending backward exceeds the rear end of the support slab.

[0020] Both the support plate and the bridge approach slab are filled with crushed stone and sand at their rear ends. The boundary between the crushed stone and sand and the soil layer is inclined upwards to achieve a transition with the filling soil layer.

[0021] Through the above design, the present invention provides a bridge approach slab structure and construction method for urban bridges. By designing an L-shaped retaining wall, on the one hand, the opening is filled with compacted soil to support the support slab. After the support slab is rigidly connected to the top of the retaining wall, the soil inside is in a semi-closed state with poor fluidity, effectively reducing the impact of roadbed settlement. On the other hand, the rigid connection between the top of the retaining wall and the back wall can reduce the corresponding settlement of the retaining wall due to foundation settlement, thus effectively reducing the impact of foundation settlement.

[0022] Moreover, the design of the compaction piles at the rear end of the support plate further improves the compaction degree at the rear end of the support plate. Since the backfill soil at the location of the compaction piles is located above the fixed retaining wall base plate and has poor fluidity, it can effectively reduce the settlement of the compaction piles themselves, thereby better supporting the support plate.

[0023] The support plate of this invention is located entirely below the bridge abutment slab, with only crushed stone and sand between it and the bridge abutment slab. The crushed stone and sand itself will not cause significant settlement. As the main load-bearing component, one end of the support plate is rigidly connected to the retaining wall and will not be displaced. The other end is located above the compaction piles. The compaction piles have reduced the impact of settlement through the special design of the retaining wall. Therefore, the support plate of this invention can effectively support the bridge abutment slab and reduce the phenomenon of bridge abutment slab jumping caused by its deformation.

[0024] Moreover, the retaining wall of this invention can be backfilled with a large amount of soil, which reduces costs compared to the existing technology of backfilling a large amount of crushed stone and sand to reduce sedimentation. Attached Figure Description

[0025] In the attached diagram: Figure 1A schematic diagram of the approach slab structure for an urban bridge. The components represented by the various reference numerals in the diagram are: 1. Abutment; 11. Abutment body; 12. Abutment cap; 13. Back wall; 14. Seismic block; 2. Retaining wall; 3. Support plate; 4. Bridge approach slab; 5. Compacting pile; 6. Roadbed. Detailed Implementation

[0026] Example 1 See Figure 1 This embodiment provides a bridge approach slab structure for an urban bridge, including an abutment 1, a retaining wall 2, a support plate 3, and a bridge approach slab 4.

[0027] Among them, the bridge abutment 1 is divided into the abutment body 11, the abutment cap 12 and the back wall 13 from bottom to top.

[0028] Urban waterways are generally narrow, and the abutment of urban bridges can adopt a ribbed structure or a cylindrical structure, with side walls on both sides of the abutment back.

[0029] The abutment cap 12 and the back wall 13 are arranged vertically. The upper sides of the abutment cap 12 are provided with anti-vibration blocks 14 to support the bridge. The back wall 13 is located at the rear end of the abutment cap 12, and a sunken platform is provided at the top rear end of the back wall.

[0030] The retaining wall 2 is set up adjacent to the rear side of the bridge abutment 1. Its longitudinal section is L-shaped, with the bottom end extending towards the roadbed 6 behind it, and the top end being rigidly connected to the back wall 13 by anchor bolts.

[0031] As a preferred embodiment, a certain gap is maintained between the vertical section of the retaining wall 2 and the rear side of the bridge abutment 1 to allow for deformation space between the two.

[0032] Furthermore, the rear end face of the back wall 13 is a smooth vertical surface, and the top height of the retaining wall 2 is higher than 1 / 3 of the height of the back wall 13, leaving space for the connection between the two.

[0033] In this embodiment, the top height of the retaining wall 2 reaches half the height of the back wall 13.

[0034] The support plate 3 is horizontally set behind the back wall 13, with its front end rigidly connected to the top of the retaining wall 2, and its rear end is equipped with compaction piles 5.

[0035] The width of the rearward extension of the support plate 3 is greater than the width of the bottom edge of the retaining wall 2, which increases the support effect on the bridge approach slab 4.

[0036] Preferably, the length of the support plate 3 is greater than half the length of the approach slab 4. During the use of urban bridges, the middle position of the approach slab 4 is the most prone to deformation. Further deformation can cause both ends to tilt upwards, leading to vehicle bounce at the approach. Therefore, having the support plate 3 longer than half the length of the approach slab 4 can effectively prevent deformation in the middle position of the approach slab 4.

[0037] The bridge approach slab 4 is horizontally set above the support plate 3, with its front end rigidly connected to the top rear end of the back wall 13, and its bottom is filled with crushed stone and sand between it and the support plate 3.

[0038] In this embodiment, the width of the bridge approach slab 4 extending rearward exceeds the rear end position of the support plate 3.

[0039] In addition to filling the space between the bottom of the bridge approach slab 4 and the support plate 3 with crushed stone and sand, the rear ends of both the support plate 3 and the bridge approach slab 4 are also filled with crushed stone and sand. The boundary between the crushed stone and the soil layer is inclined upwards to achieve a transition with the filling soil layer.

[0040] The crushed stone sand referred to in this embodiment is a mixture of cement and crushed stone, and the graded crushed stone is consolidated by cement.

[0041] In this embodiment, the abutment 1, retaining wall 2, support plate 3, and approach slab 4 are all reinforced concrete structures.

[0042] Furthermore, the support plate 3, retaining wall 2, and bridge approach slab 4 are all prefabricated components, which can improve on-site construction efficiency.

[0043] Example 2 The present invention also provides a construction method for a bridge approach slab 4 of an urban bridge, which adopts the bridge approach slab structure of Embodiment 1, and specifically includes the following steps: S1, the main body of the construction bridge abutment 1, is constructed using ultra-high performance concrete precast retaining wall 2, support plate 3, and bridge approach slab 4.

[0044] S2. Construct retaining wall 2 on the foundation behind abutment 1, and rigidly connect the top of retaining wall 2 to back wall 13.

[0045] The vertical section of retaining wall 2 should be arranged parallel to the back wall 3.

[0046] S3. Backfill soil in layers between retaining wall 2 and roadbed 6, and compact each layer with a compaction degree of not less than 96%, until the height reaches the top of retaining wall 2.

[0047] The roadbed 6 and the retaining wall 2 adopt an inverted trapezoidal transition form.

[0048] As a preferred embodiment, when backfilling soil in layers, flexible materials such as geogrids can also be used to better lock the soil in place.

[0049] S4. Based on the length of the support plate 3, construct compaction piles 5 at a predetermined distance behind the top of the retaining wall 2 along the width of the bridge.

[0050] The distance between the compaction pile 5 and the front face of the retaining wall 2 is matched with the width dimension of the support plate 3 extending backward.

[0051] In this embodiment, the compaction piles 5 are arranged in two rows, with the vertical projection of one row located on the bottom edge of the retaining wall 2 and the other row located outside the bottom edge. This is a key design feature of the present invention, which can effectively prevent the compaction piles 5 from settling with the soil layer, thereby providing long-term and effective support for the support plate 3.

[0052] S5. Hoist the support plate 3 so that its front end rests on the top of the retaining wall 2 and its rear end rests on the compaction pile 5. Then, rigidly connect the front end of the support plate 3 to the top of the retaining wall 2.

[0053] To further improve the contact density between the support plate 3 and the soil layer below, the backfill soil inside the retaining wall 2 can be a certain distance above the top of the retaining wall 2. After the support plate 3 is placed, it will be pressed down to be level with the top of the retaining wall 2 under the action of gravity.

[0054] S6. Backfill soil in layers between the rear of the support plate 3 and the roadbed 6, and compact each layer.

[0055] S7. Fill the support plate 3 with crushed stone and sand and compact it.

[0056] The use of mortar volume to fill the voids in the crushed stone aggregate results in a cement-stabilized crushed stone structural layer with high strength, impermeability, and frost resistance. This effectively reduces reflective cracking on the road surface of the bridge approach slab 4, thereby reducing unevenness caused by road surface cracks and alleviating vehicle bounce. It also avoids "cliff-like" elevation differences and reduces vehicle impact.

[0057] S8. Lay the bridge approach slab 4 on top of the gravel and sand, and rigidly connect its front end to the rear end platform at the top of the back wall 13.

[0058] Finally, the road base and road surface layers are constructed above the bridge abutment 1 and the bridge approach slab 4.

[0059] While continuing to backfill the soil in layers, pay attention to filling the rear ends of the support plate 3 and the bridge approach plate 4 with crushed stone and sand. The boundary line between the crushed stone and the soil layer is inclined upward to achieve a transition with the backfill soil layer.

[0060] The design of the L-shaped retaining wall 2 in this application has two aspects. First, the opening is filled with compacted soil to support the support plate 3. After the support plate 3 is rigidly connected to the top of the retaining wall 2, the soil inside is in a semi-closed state with poor fluidity, which prevents it from settling downwards, thus effectively reducing the impact of the roadbed 6 settlement. Second, the rigid connection between the top of the retaining wall 2 and the back wall 13 can reduce the corresponding settlement of the retaining wall 2 due to the foundation settlement, thus effectively reducing the impact of the foundation settlement.

[0061] Moreover, the design of the compaction pile 5 at the rear end of the support plate 3 further improves the compaction degree at the rear end of the support plate 3. Since the backfill at the location of the compaction pile 5 is located above the fixed retaining wall 2 bottom plate, the fluidity is poor, which can effectively reduce the settlement of the compaction pile 5 itself, thereby better supporting the support plate 3.

[0062] The support plate 3 of this invention is located entirely below the bridge approach slab 4, with only crushed stone and sand between it and the bridge approach slab 4. The crushed stone and sand itself will not cause significant settlement. As the main load-bearing component, one end of the support plate 3 is rigidly connected to the retaining wall 2 and will not be displaced. The other end is located above the compaction pile 5. The compaction pile 5 has reduced the impact of settlement through the special design of the retaining wall 2. Therefore, the support plate 3 of this invention can effectively support the bridge approach slab 4 and reduce the phenomenon of bridge approach slab jumping caused by its deformation.

[0063] That is, the present invention can effectively reduce the settlement of the bridge approach slab caused by the settlement of the roadbed 6 and the foundation through the coordinated cooperation of the L-shaped retaining wall 2, the support plate 3 and the compaction pile 5, and at the same time provide effective support for the bridge approach slab to prevent it from deforming and bending, thus effectively reducing the risk of bridge approach slab settlement.

[0064] Moreover, the retaining wall 2 of the present invention can be backfilled with a large amount of soil, which reduces costs compared to the existing technology of backfilling a large amount of crushed stone and sand to reduce sedimentation.

Claims

1. A bridge approach slab structure for urban bridges, characterized in that, include: The bridge abutment (1) is divided into abutment body (11), abutment cap (12) and back wall (13) from bottom to top. Anti-vibration blocks (14) are installed on the upper sides of the abutment cap (12), and the back wall (13) is located at the rear end of the abutment cap (12). The retaining wall (2) is set up close to the rear side of the bridge abutment (1). Its longitudinal section is L-shaped, with the bottom end extending towards the roadbed (6) behind it and the top end rigidly connected to the back wall (13). The support plate (3) is horizontally set behind the back wall (13), and its front end is rigidly connected to the top of the retaining wall (2). The rear end is equipped with compaction piles (5). The bridge approach slab (4) is horizontally set above the support plate (3), with its front end connected to the top rear end of the back wall (13), and its bottom filled with gravel and sand between it and the support plate (3).

2. The bridge approach slab structure for urban bridges according to claim 1, characterized in that, The abutment (1), retaining wall (2), support plate (3) and approach slab (4) are all reinforced concrete structures.

3. A construction method for bridge approach slabs of urban bridges, characterized in that, The bridge approach slab structure according to claim 1 or 2 specifically includes the following steps: S1, Construction abutment (1) body; S2. Construct a retaining wall (2) on the foundation behind the bridge abutment (1) and rigidly connect the top of the retaining wall (2) to the back wall (13); S3. Backfill soil in layers between the retaining wall (2) and the roadbed (6), and compact each layer until the height reaches the top of the retaining wall (2); S4. Based on the length of the support plate (3), compaction piles (5) are constructed at a predetermined distance behind the top of the retaining wall (2) along the width of the bridge. S5. Hoist the support plate (3) so that its front end rests on the top of the retaining wall (2) and its rear end rests on the compaction pile (5). Then, rigidly connect the front end of the support plate (3) to the top of the retaining wall (2). S6. Backfill soil in layers between the rear of the support plate (3) and the roadbed (6), and compact each layer. S7. Fill the support plate (3) with crushed stone and sand and compact it; S8. Lay the bridge approach slab (4) on top of the gravel and sand, and rigidly connect its front end to the rear end platform of the back wall (13).

4. The construction method according to claim 3, characterized in that, The rear end face of the back wall (13) is a smooth vertical surface, and the top height of the retaining wall (2) is higher than 1 / 3 of the height of the back wall (13).

5. The construction method according to claim 3, characterized in that, The width of the support plate (3) extending backward is greater than the width of the bottom edge of the retaining wall (2).

6. The construction method according to claim 3, characterized in that, The support plate (3), retaining wall (2) and bridge approach slab (4) are all prefabricated components.

7. The construction method according to claim 3, characterized in that, In step S4, the distance between the compaction pile (5) and the front face of the retaining wall (2) matches the width dimension of the support plate (3) extending backward.

8. The construction method according to claim 7, characterized in that, The compaction piles (5) are arranged in one or more rows, and at least one row has its vertical projection located on the bottom edge of the retaining wall (2).

9. The construction method according to claim 3, characterized in that, The width of the bridge approach plate (4) extending backward exceeds the rear end position of the support plate (3).

10. The construction method according to claim 3, characterized in that, Both the support plate (3) and the bridge approach plate are filled with crushed stone and sand at the rear end, with the boundary between the crushed stone and sand and the soil layer sloping upwards.

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