Bridge head roadbed composite structure for preventing bridge head bump and construction method thereof

Abstract

The application discloses a bridge-head roadbed composite structure for preventing bridge-head bumping, which comprises, from top to bottom, an asphalt surface layer, a road surface structure layer, a clamping plate and a sleeper beam; one end of the clamping plate is clamped on a bracket of an abutment back wall and abuts against the abutment, and the other end of the clamping plate is clamped on the sleeper beam, and the integrality of the sleeper beam and the clamping plate is realized through a steel joint; a first-grade graded gravel cushion layer is arranged below the clamping plate and on both sides of the sleeper beam, and drainage facilities are arranged in the first-grade graded gravel cushion layer; a non-woven geotextile anti-filtration layer is wrapped on the outer side of the first-grade graded gravel cushion layer, and the upper surface of the geotextile anti-filtration layer is connected with the road surface structure layer; and a second-grade graded gravel cushion layer can be further arranged beside the bearing platform, and transverse drainage facilities are arranged in the second-grade graded gravel cushion layer. The application further discloses a construction method of the bridge-head roadbed composite structure. The bridge-head roadbed composite structure changes the bearing characteristics of the roadbed, reduces the effect of the road surface load on the roadbed, enhances the bearing capacity and strength of the roadbed, and reduces the uneven settlement of the roadbed; the drainage system of the bridge-head roadbed is optimized, and the water accumulation in the roadbed is effectively avoided; the bridge-head roadbed composite structure has good durability and high stability; and the bridge-head roadbed composite structure is convenient to construct and has strong popularization.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, and in particular to a composite structure for bridge approach roadbed and its construction method for preventing bridge approach slab settlement. Background Technology

[0002] Bridge approach slab slab slab refers to the phenomenon where vehicle wheels vibrate up and down when passing over a section of road due to settlement or other factors between the bridge / culvert structure and the embankment behind the bridge / culvert abutment exceeding a certain limit. This settlement phenomenon affects the normal use of highways and people's overall evaluation of them. At the same time, the up and down vibration of the wheels also affects driving safety, speed, comfort, and the service life of both vehicles and bridges.

[0003] Bridge approach slab settlement is caused by the differential settlement between the rigidly supported abutment and the relatively flexible embankment. The international solution to this problem is to add a 30-50m long transition section between the rigid abutment and the flexible embankment, with the fill material gradation gradually changing until the transition is complete at the bridge approach. While this method reduces differential settlement and alleviates bridge approach slab settlement, it does not provide specific design methods, only generally suggesting that bridge approach slab settlement be treated as an independent design problem and that its prevention be included as one of the design objectives. Furthermore, methods proposed by many domestic experts and scholars, such as adding bridge approach slab structures, pre-embankment height methods, and special treatment of the bridge approach subgrade, cannot completely solve the problem of bridge approach slab settlement and need to be used in conjunction with other treatment measures.

[0004] Chinese Patent No. CN 213114272 U discloses a bridge abutment slab structure for hydraulic bridges, including an anti-settlement layer placed on the bridge abutment subgrade and a support layer placed on the upper surface of the anti-settlement layer. One end of the anti-settlement layer abuts against the abutment corbel, and the other end abuts against the sleeper beam. The anti-settlement layer includes a first rubber layer and multiple rubber blocks evenly distributed on the lower surface of the first rubber layer. The support layer is a concrete layer, with one end overlapping the abutment corbel and abutting against the abutment, and the other end overlapping the sleeper beam. Multiple reinforcing beams are evenly arranged at the lower part of the support layer. This technical solution has the technical effect of resisting bridge abutment settlement, reducing the impact of passing vehicles on the bridge abutment foundation, and delaying the settlement of the bridge abutment foundation. However, the rubber material with the anti-settlement layer has poor stability, and the overall solution is difficult to construct.

[0005] Therefore, developing a bridge approach roadbed structure that can prevent bridge approach slab settlement, improve the problem of insufficient bearing capacity of bridge approach roadbed, and has good stability and is easy to construct is an urgent problem to be solved. Summary of the Invention

[0006] In view of the above-mentioned defects in the existing technology, the present invention provides a composite structure for bridge approach roadbed to prevent bridge approach slab settlement, so as to solve the problems of bridge approach slab settlement, insufficient bearing capacity of bridge approach roadbed, poor stability of roadbed structure and complex construction.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] On one hand, a composite structure for preventing bridge approach slab settlement is provided at the bridge approach abutment. The upper part of the abutment has an integrally formed abutment ear wall with corbels. The structure, from top to bottom, comprises an asphalt surface layer, a pavement structure layer, an approach slab, and a sleeper beam. One end of the approach slab overlaps the corbel of the abutment ear wall and abuts against the abutment, while the other end overlaps the sleeper beam. The sleeper beam is arranged laterally, with a pre-reserved steel bar joint at the upper end, achieving the integrity of the sleeper beam and the approach slab through the steel bar joint. A first-grade crushed stone cushion layer is provided below the approach slab and on both sides of the sleeper beam. The first-grade crushed stone cushion layer contains a flexible permeable pipe, which is connected to the drainage system on both sides of the roadbed through a cone-shaped drainage hole. The outer surface of the first-grade crushed stone cushion layer is wrapped with a non-woven geotextile filter layer, the upper surface of which is in contact with the pavement structure layer.

[0009] The composite subgrade structure for preventing bridge approach slab settlement provided by this invention alters the subgrade bearing characteristics, reduces the impact of pavement loads on the subgrade, enhances the subgrade's bearing capacity and strength, and reduces uneven subgrade settlement. The corbels and sleeper beams at both ends of the approach slab provide simple support, giving the approach slab and its upper part a vertical support, increasing the vertical stiffness of the bridge-road transition zone at the bridge end. As the main load-bearing layer of the short subgrade pavement, the approach slab reduces uneven settlement deformation caused by insufficient subgrade compaction and prevents damage to the pavement structure due to uneven stress. The graded crushed stone under the approach slab also enhances the bearing capacity. The graded crushed stone on the outer side of the approach slab and sleeper beams provides permeability; the non-woven geotextile filters the sand and gravel, allowing only water to pass through, allowing water seeping from the upper part of the approach slab into the graded crushed stone, and then draining the water through internal flexible permeable pipes, effectively preventing water accumulation from harming the subgrade structure.

[0010] Preferably, the cross-sectional dimensions of the bolster beam are 50×50cm. This feature gives the bolster beam more reasonable support strength.

[0011] Preferably, the approach slab is a structure consisting of steel mesh binding and concrete pouring. This feature results in high load-bearing capacity and good durability of the approach slab structure itself.

[0012] Preferably, a second graded crushed stone cushion layer is provided next to the pier cap, and a transverse drainage system is installed within the second graded crushed stone cushion layer. This feature further increases the bearing capacity and settlement resistance of the roadbed.

[0013] Preferably, the drainage facility consists of 3 to 5 rows of flexible permeable pipes, which are connected to the drainage system on both sides of the roadbed through conical slope drainage holes. This feature further optimizes the drainage performance of the roadbed composite structure.

[0014] Preferably, a permeable layer is laid between the second grade crushed stone subbase and the first grade crushed stone subbase. This feature further accelerates subgrade drainage and reduces subgrade water accumulation.

[0015] Preferably, a permeable nonwoven geotextile filter layer is provided at the interface between the permeable layer and the second grade crushed stone cushion layer.

[0016] On the other hand, a construction method for a composite structure of bridge approach subgrade to prevent bridge approach slab settlement is characterized by comprising the following steps:

[0017] S1. Construction of the bridge abutment foundation. After the bridge abutment is constructed, a graded crushed stone cushion layer of the same height as the abutment is laid next to the abutment and up to the excavated slope. A geotextile filter layer is laid on the upper surface of the graded crushed stone, with a transverse soft permeable pipe built in. The water enters the drainage system on both sides of the roadbed through the cone slope drainage hole.

[0018] S2. Construction of abutments and approach slabs. When the upper surface of the permeable material backfilled behind the abutment reaches the bottom elevation of the sleeper beam, sleeper beam construction is carried out. Graded crushed stone is laid to the top of the sleeper beam, and the reinforcement mesh of the approach slab is tied and the concrete is poured. After the concrete of the approach slab reaches a certain strength, the next step of construction is carried out.

[0019] S3. Construction of drainage facilities for the approach slab. A layer of graded crushed stone is laid on the side where the approach slab connects to the sleeper beam. The graded crushed stone is wrapped with a layer of geotextile filter layer and has a built-in transverse soft permeable pipe. The water enters the drainage system on both sides of the roadbed through the cone slope drainage hole, and the water on the upper layer of the approach slab is discharged to the slope drainage ditch.

[0020] S4. Construction of the upper road structure layer of the approach slab.

[0021] S5. An asphalt surface layer is then laid on top of the road structure layer.

[0022] Compared with the prior art, the above invention has the following advantages or beneficial effects:

[0023] (1) Enhance the bearing capacity and strength of the bridge abutment subgrade and reduce uneven settlement of the bridge abutment subgrade;

[0024] (2) Optimize the drainage system of the bridgehead roadbed to effectively avoid the damage of water accumulation to the roadbed structure;

[0025] (3) The bridgehead subgrade structure has good durability and high stability;

[0026] (4) It can effectively reduce the slab jump at the first end of the bridge behind the platform and avoid the slab jump at the last end of the bridge behind the platform, making the driving on the back road comfortable and smooth, and improving the safety of the driving road.

[0027] (5) Convenient construction and easy to promote.

[0028] This invention discloses a composite structure for bridge abutment subgrade to prevent bridge approach slab settlement. From top to bottom, it includes an asphalt surface layer, a pavement structure layer, an approach slab, and sleeper beams. One end of the approach slab overlaps the corbel of the abutment abutment wall and abuts against the abutment, while the other end overlaps the sleeper beams. The sleeper beams and approach slabs are integrated through steel reinforcement joints. A first-grade crushed stone cushion layer is provided below the approach slab and on both sides of the sleeper beams, with built-in drainage facilities. The outer surface of the first-grade crushed stone cushion layer is wrapped with a non-woven geotextile filter layer, the upper surface of which is in contact with the pavement structure layer. A second-grade crushed stone cushion layer can also be provided next to the abutment, with transverse drainage facilities installed within it. This invention also discloses a construction method for the aforementioned composite structure for bridge abutment subgrade. The bridge abutment subgrade composite structure of the present invention changes the bearing characteristics of the subgrade, reduces the effect of pavement load on the subgrade, enhances the bearing capacity and strength of the subgrade, and reduces uneven settlement of the subgrade; optimizes the drainage system of the bridge abutment subgrade to effectively avoid water accumulation in the subgrade; has good durability and high stability; is easy to construct and has strong applicability. Attached Figure Description

[0029] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not drawn to scale; their focus is on illustrating the gist of the invention.

[0030] Figure 1 This is a cross-sectional schematic diagram of the bridge abutment roadbed composite structure of the present invention;

[0031] Among them, 1 is the asphalt surface layer, 2 is the beam body, 3 is the support, 4 is the abutment back wall, 5 is the pavement structure, 6 is the approach slab, 7 is the sleeper beam, 91 is the first-grade crushed stone cushion layer, 92 is the second-grade crushed stone cushion layer, 81 is the soft permeable pipe inside the first-grade crushed stone layer, 82 is the soft permeable pipe inside the second-grade crushed stone layer, 101 is the geotextile filter layer, 102 is the permeable non-woven geotextile filter layer, 11 is the pile cap, 12 is the pile foundation, and 13 is the permeable layer. Detailed Implementation

[0032] The structure of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0033] Example 1

[0034] like Figure 1As shown, a composite structure for preventing bridge approach slab settlement is provided at the bridge approach abutment 11. The upper end of the abutment 11 has an integrally formed abutment ear back wall 4 with corbels. From top to bottom, it includes an asphalt surface layer 1, a pavement structure layer 5, a slab 6, and a sleeper beam 7. One end of the slab 6 overlaps the corbel of the abutment ear back wall 4 and abuts against the abutment, while the other end overlaps the sleeper beam 7. The sleeper beam 7 is arranged laterally, with a pre-reserved steel bar joint at the upper end, which achieves the integrity of the sleeper beam 7 and the slab 6. A first-grade crushed stone cushion layer 91 is provided below the slab 6 and on both sides of the sleeper beam 7. The first-grade crushed stone cushion layer 91 has a built-in flexible permeable pipe 81, which is connected to the drainage system on both sides of the roadbed through a cone slope drainage hole. The outer surface of the first-grade crushed stone cushion layer 91 is wrapped with a non-woven geotextile filter layer 101, and the upper surface of the geotextile filter layer 101 is in contact with the pavement structure layer 5. The preferred cross-sectional dimensions of the sleeper beam are 50×50cm. The approach slab is a structure consisting of steel mesh binding and concrete pouring. A second-grade crushed stone cushion layer 92 can also be installed next to the pile cap 11. Three rows of flexible permeable pipes 82 are horizontally embedded in the second-grade crushed stone cushion layer 92, and the flexible permeable pipes 82 are connected to the drainage system on both sides of the roadbed through the conical slope drainage holes. A permeable layer 13 is laid between the second-grade crushed stone cushion layer 92 and the first-grade crushed stone cushion layer 91. A permeable non-woven geotextile filter layer 102 is installed at the interface between the permeable layer 13 and the second-grade crushed stone cushion layer 92.

[0035] In this embodiment, after the pile foundation 12 is completed, the pile cap 11 and the abutment abutment back wall 4 are constructed. The bridge abutment beam 2 is installed on the support 3 of the abutment abutment back wall 4. Then, the composite structure of the bridge abutment subgrade is constructed. The construction method includes the following steps:

[0036] S1. Lay a graded crushed stone cushion layer of the same height as the pile cap from the side of the pile cap to the excavated slope. Lay a geotextile filter layer on the upper surface of the graded crushed stone and install 3 rows of transverse soft permeable pipes. The water enters the drainage system on both sides of the roadbed through the cone slope drainage holes.

[0037] S2. Construction of abutments and approach slabs. When the upper surface of the permeable material backfilled behind the abutment reaches the bottom elevation of the sleeper beam, sleeper beam construction is carried out. Graded crushed stone is laid to the top of the sleeper beam, and the reinforcement mesh of the approach slab is tied and the concrete is poured. After the concrete of the approach slab reaches a certain strength, the next step of construction is carried out.

[0038] S3. Construction of drainage facilities for the approach slab. A layer of graded crushed stone is laid on the side where the approach slab connects to the sleeper beam. The graded crushed stone is wrapped with a layer of geotextile filter layer and has a built-in transverse soft permeable pipe. The water enters the drainage system on both sides of the roadbed through the cone slope drainage hole, and the water on the upper layer of the approach slab is discharged to the slope drainage ditch.

[0039] S4. Construction of the upper road structure layer of the approach slab;

[0040] S5. An asphalt surface layer is then laid on top of the road structure layer.

[0041] Example 2

[0042] A composite structure and construction method for preventing bridge approach slab settlement is basically the same as that in Example 1, except that five rows of flexible permeable pipes are horizontally buried in the second grade crushed stone cushion layer.

[0043] In summary, this application provides a composite structure and construction method for bridge abutment subgrade to prevent bridge approach slab settlement. The composite structure comprises, from top to bottom, an asphalt surface layer, a pavement structure layer, an approach slab, and a sleeper beam. One end of the approach slab overlaps the corbel of the abutment abutment wall and abuts against the abutment, while the other end overlaps the sleeper beam. The sleeper beam and approach slab are integrated through steel reinforcement joints. A first-grade crushed stone cushion layer is provided below the approach slab and on both sides of the sleeper beam, with built-in drainage facilities. The outer surface of the first-grade crushed stone cushion layer is wrapped with a non-woven geotextile filter layer, the upper surface of which is in contact with the pavement structure layer. A second-grade crushed stone cushion layer can also be provided beside the abutment, with transverse drainage facilities installed within it. This composite structure for bridge abutment subgrade alters the bearing characteristics of the subgrade, reduces the effect of pavement load on the subgrade, enhances the bearing capacity and strength of the subgrade, and reduces uneven subgrade settlement. It also optimizes the drainage system of the bridge abutment subgrade, effectively preventing water accumulation. Furthermore, it exhibits good durability and high stability. The construction method of the bridge abutment roadbed composite structure of the present invention is easy to construct and highly practical.

[0044] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments, which will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here either.

[0045] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A bridge head subgrade composite structure for preventing bridge head bumping, arranged at a bridge head pile cap (11), the pile cap (11) being integrally formed at the upper end with a bridge abutment ear back wall (4) with corbels, characterized in that: from top to bottom, it comprises an asphalt surface layer (1), a pavement structure layer (5), a lap plate (6) and a sleeper beam (7); one end of the lap plate (6) is lapped on the corbel of the bridge abutment ear back wall (4) and abuts against the bridge abutment, the other end of the lap plate is lapped on the sleeper beam (7), the sleeper beam (7) is arranged transversely, and a steel joint is reserved at the upper end to realize the integrity of the sleeper beam (7) and the lap plate (6); a first graded gravel cushion layer (91) is arranged below the lap plate (6) and on both sides of the sleeper beam (7), a first soft type permeable pipe is arranged in the first graded gravel cushion layer (91), and the first soft type permeable pipe is connected to a drainage system on both sides of the subgrade through a conical slope drainage hole; an outer side surface of the first graded gravel cushion layer (91) is wrapped with a non-woven geotextile filter layer (101), and an upper surface of the geotextile filter layer (101) is connected to the pavement structure layer (5); a second graded gravel cushion layer (92) is arranged beside the pile cap (11), horizontal drainage facilities are arranged in the second graded gravel cushion layer (92), the drainage facilities are 3 to 5 rows of second soft type permeable pipes, the second soft type permeable pipes are connected to the drainage system on both sides of the subgrade through conical slope drainage holes, and a permeable layer (13) is arranged between the second graded gravel cushion layer (92) and the first graded gravel cushion layer (91). The cross-sectional size of the sleeper beam (7) is 50*50 cm.

2. The bridge head embankment composite structure for preventing bridge head bump according to claim 1, wherein The lap plate (6) is a structure of steel mesh binding and concrete pouring.

3. The bridge abutment subgrade composite structure for preventing bridge head bumping according to claim 1, characterized in that, A permeable non-woven geotextile filter layer (102) is arranged at the interface between the permeable layer (13) and the second graded gravel cushion layer (92).

4. The bridge abutment subgrade composite structure for preventing bridge head bumping according to claim 1, characterized in that, The steps include:

5. The construction method of a bridge head embankment composite structure for preventing bridge head bump according to any one of claims 1 to 4, characterized in that, S1, pile cap foundation construction; S2, bridge abutment and lap plate construction; S3, lap plate drainage facility construction; S4, upper road structure layer construction of the lap plate; S5, asphalt surface layer paving on the road structure layer. ​

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