A subgrade structure suitable for bridge connection and a construction method thereof

Abstract

An embodiment of the present application provides a subgrade structure suitable for bridge connection and a construction method, belonging to the technical field of bridge-road connection. The subgrade structure includes a bridge and a subgrade. The bridge includes side beams located on one side in its width direction. The subgrade includes a base layer, a plurality of backfill layers, and a plurality of retaining walls. The base layer has a slope protection. The plurality of backfill layers are sequentially arranged on the base layer from bottom to top. One retaining wall is arranged on the side of each backfill layer close to the slope protection in the horizontal direction. Among every two adjacent retaining walls, the upper retaining wall is farther away from the slope protection in the horizontal direction than the lower retaining wall. The uppermost retaining wall among the plurality of retaining walls is connected to the side beam. This subgrade structure can improve the problem of poor stability of bridge-road connection.

Description

Technical Field

[0001] This application relates to the technical field of road and bridge connections. Specifically, it relates to a subgrade structure and construction method applicable to bridge-road connections. Background Art

[0002] With the development of social economy, human economic activities have become increasingly frequent, and the construction density of bridge projects has also increased accordingly. The layout of bridges on highways and local arterial roads has become normal, and the form of their mutual influence and intersection with surrounding roads has become increasingly serious and complex. However, the traditional approach is to lay the road network intersection section in the subgrade engineering section and avoid bridge projects because it is difficult to find a suitable breakthrough for the intersecting road in the subgrade section to cross the long-span continuous beam bridge smoothly, and there are also problems with poor stability between the intersecting and connected bridges and roads. Summary of the Invention

[0003] An embodiment of this application provides a subgrade structure and construction method applicable to bridge-road connections to improve the problem of poor bridge-road connection stability.

[0004] In a first aspect, an embodiment of this application provides a subgrade structure applicable to bridge-road connections. The subgrade structure includes a bridge and a subgrade. The bridge includes side beams located on one side in its width direction. The subgrade includes a base layer, multiple backfill layers, and multiple retaining walls. The base layer has a slope protection. The multiple backfill layers are sequentially arranged on the base layer from bottom to top. One retaining wall is provided on the side of each backfill layer close to the slope protection in the horizontal direction. Among every two adjacent retaining walls, the upper retaining wall is farther from the slope protection in the horizontal direction than the lower retaining wall. Among the multiple retaining walls, the uppermost retaining wall is connected to the side beam.

[0005] In the above technical solution, by forming a slope protection at the bottom of the slope of the base layer, while ensuring coordination with the surrounding environment, the stability of the slope toe of the subgrade structure can be effectively enhanced. By adopting the method of gradually multi-layer retaining walls on the base layer, the problem of insufficient stability of the filled subgrade is improved, and the structure of the multi-layer retaining walls can adapt to a higher height than ordinary retaining walls, and is more suitable for the construction of high-filled subgrades. Compared with the super-large cross-section super-high retaining walls, the stability of the subgrade structure is improved, and the use of multi-level retaining walls can save masonry work, is safer in structure, and more economical in terms of economy. More importantly, in this solution, the subgrade adopts a slope protection and multi-layer retaining wall structure, which lays a foundation for the lateral connection of the road and bridge, enabling the side beam of the bridge to be constructed in a lateral connection manner with the retaining wall of the subgrade, and solving the problems of difficult lateral connection and poor stability between the road project and the bridge project.

[0006] In some embodiments, the roadbed structure further comprises a telescopic mechanism, which is connected to the uppermost retaining wall and the side beam. An expansion joint is formed between the uppermost retaining wall and the side beam, and the telescopic mechanism is used to allow the uppermost retaining wall and the side beam to be able to expand and contract along the width direction of the expansion joint.

[0007] In the above technical solution, by forming an expansion joint between the uppermost retaining wall and the side beam, and effectively connecting them through a telescopic device, the deformation of the road fill roadbed and the connecting side beam can be coordinated, thereby ensuring the overall structural safety of the bridge, effectively alleviating the phenomenon of vehicle jumping at the bridge head, and ensuring a smooth connection between the bridge and the road.

[0008] In some embodiments, a first groove is provided on the side of the uppermost retaining wall among the multiple retaining walls close to the side beam, and a second groove is provided on the side of the side beam close to the uppermost retaining wall among the multiple retaining walls; the first groove and the second groove cooperate to form a accommodating groove for accommodating the telescopic mechanism.

[0009] In the above technical solution, the telescopic mechanism is partially located in the uppermost retaining wall and partially located in the side beam, thereby forming a accommodating space for the telescopic mechanism, which can limit the telescopic mechanism and prevent the telescopic mechanism from shifting. The uppermost retaining wall and the side beam are effectively connected by the telescopic mechanism, thereby improving the connection stability of the telescopic mechanism.

[0010] In some embodiments, the roadbed structure further includes a first slope protection platform, which is disposed on the top of the base layer and is located between the slope protection and the lowest retaining wall among the plurality of retaining walls in a horizontal direction.

[0011] In the above technical solution, by building a first slope protection platform between the slope protection and the lowest retaining wall, the first slope protection platform can effectively prevent rainwater from penetrating into the base layer, thereby avoiding rainwater infiltration from affecting the overall stability of the base layer.

[0012] In some embodiments, the roadbed structure also includes a second slope protection platform, which is arranged on the top of the backfill layer and is located horizontally between two adjacent retaining walls among the multiple retaining walls, so that the retaining wall located on the upper side is farther away from the slope protection in the horizontal direction than the retaining wall located on the lower side.

[0013] In the above technical solution, the second slope protection platform is built on the top of the backfill layer and located between the upper and lower adjacent retaining walls, which can effectively prevent rainwater from infiltrating into the backfill layer and effectively improve the problem of insufficient stability of the high fill roadbed. In addition, the second slope protection platform can provide an inspection channel for the bridge beams and slabs during the operation period, which is convenient for the inspection and maintenance of the bridge.

[0014] In some embodiments, the retaining wall includes a base plate and a wall body, the base plate and the wall body are connected, and the wall body is provided with a plurality of drainage holes, and the drainage holes penetrate the wall body along the thickness direction of the wall body.

[0015] In the above technical solution, through a plurality of drainage holes provided on the wall body, the accumulated water in the backfill layer can be effectively discharged, avoiding the water level in the backfill layer being too high due to long-term accumulation of water in the backfill layer, which affects the stability of the backfill soil in the backfill layer.

[0016] In some embodiments, a gravel filter layer is provided between the wall body of the retaining wall and the backfill layer.

[0017] In the above technical solution, through the gravel filter layer, the accumulated water in the backfill layer inside the retaining wall can be effectively filtered, preventing the backfill soil from being discharged through the drainage holes, and avoiding the phenomenon that the overall stability of the roadbed structure is affected due to the loss of water and soil of the backfill soil in the roadbed.

[0018] In a second aspect, the embodiments of the present application further provide a construction method for a roadbed structure suitable for bridge-road connection. The construction method includes the following steps: backfilling the slope bottom of the roadbed and compacting the backfill material by rolling to form a base layer with a slope protection. Construct a plurality of backfill layers and a plurality of retaining walls on the base layer from bottom to top. Among them, after constructing a retaining wall, a corresponding backfill layer is constructed, so that each retaining wall is located on the side of the corresponding backfill layer close to the slope protection in the horizontal direction, and the retaining wall located on the upper side is farther away from the slope protection in the horizontal direction than the retaining wall located on the lower side. Connect the uppermost retaining wall to the side beam of the bridge.

[0019] In the above construction method, a slope protection is first formed at the slope bottom of the base layer, which can effectively enhance the stability of the slope toe of the roadbed structure while ensuring coordination with the surrounding environment. Then, by adopting a step-by-step multi-layer retaining wall method on the base layer, the problem of insufficient stability of the filled roadbed is improved, and the structure of the multi-layer retaining wall can adapt to a higher height than that of a common retaining wall, and is more suitable for the construction of high-filled roadbeds. Compared with the super-large cross-section super-high retaining wall, the stability of the roadbed structure is improved, and the use of a multi-stage retaining wall form can save masonry work, is safer in structure, and more economical. More importantly, in this solution, the roadbed adopts a slope protection and multi-layer retaining wall structure, which lays a foundation for the lateral connection of the road bridge, enabling the side beam of the bridge to be laterally connected to the retaining wall of the roadbed, and solving the problems of difficult lateral connection and poor stability between the road engineering and the bridge engineering.

[0020] In some embodiments, before constructing the lowermost retaining wall, a first slope protection platform is constructed on the top of the base layer, so that the first slope protection platform is located between the slope protection and the lowermost retaining wall among the plurality of retaining walls.

[0021] In the above technical solution, through the first slope protection platform, the retaining wall can effectively prevent rainwater from infiltrating into the base layer, ensuring the stability of the base layer.

[0022] In some embodiments, during the construction of two adjacent retaining walls, before constructing the upper retaining wall on the backfill layer, a second slope protection platform is constructed on the top of the backfill layer so that the second slope protection platform is located between two adjacent retaining walls among multiple retaining walls.

[0023] In the above technical solution, by constructing the second slope protection platform on the top of the backfill layer and locating it between the upper and lower adjacent retaining walls, rainwater infiltration into the backfill layer can be effectively prevented, and the problem of insufficient stability of the high fill subgrade is effectively improved.

[0024] Other features and advantages of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 A top view schematic diagram of a subgrade structure applicable to bridge-road connection provided by some embodiments of the present application;

[0027] Figure 2 For Figure 1 A cross-sectional view taken along A-A in

[0028] Figure 3 For Figure 2 A partial schematic diagram of the side beam and the second retaining wall in

[0029] Figure 4 For Figure 2 A structural schematic diagram of the first retaining wall and the first backfill layer in

[0030] Reference numerals: base course 10, steep slope 11, step surface 12, slope protection 13, first slope protection platform 20, first retaining wall 30, bottom slab 31, wall body 32, drain hole 321, gravel filter layer 33, first backfill layer 40, second slope protection platform 50, second retaining wall 60, abutment cap 61, first groove 610, second backfill layer 70, side beam 80, second groove 81, expansion joint 90, subgrade structure 100, road 101, bridge 102. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some, but not all, of the embodiments of this application. Components of the embodiments of this application usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0033] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0034] In the description of the embodiments of this application, it should be noted that the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this application is habitually placed during use, or the orientation or positional relationship in which the product of this application is habitually placed during use. This is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In addition, the terms "first", "second", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0035] In the description of this application, it should also be noted that unless otherwise clearly specified and limited, the terms "set" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0036] Embodiment

[0037] Please refer to Figure 1 , the embodiments of this application provide a subgrade structure applicable to bridge-road connection. The so-called bridge-road connection refers to the connection between the bridge 102 and the road 101 in a lateral connection manner. It can be understood that the lateral connection means that the bridge 102 and the road 101 are connected at a certain angle. For example, they are connected at a 90-degree angle. Figure 1 Exemplarily shows the situation where the bridge 102 and the road 101 are connected at a 90-degree angle.

[0038] Please refer to Figure 2 , the subgrade structure 100 includes a bridge 102 and a subgrade. The bridge 102 includes side beams 80 on one side in its width direction. The subgrade includes a base course, multiple backfill layers, and multiple retaining walls. The base course 10 has a slope protection 13. The multiple backfill layers are sequentially arranged on the base course 10 from bottom to top. Each backfill layer is provided with a retaining wall on the side close to the slope protection 13 in the horizontal direction. Among every two adjacent retaining walls, the upper retaining wall is farther away from the slope protection 13 in the horizontal direction than the lower retaining wall. Among them, the uppermost retaining wall among the multiple retaining walls is connected to the side beam 80.

[0039] By forming a slope protection 13 at the bottom of the slope of the base course 10, while ensuring coordination with the surrounding environment, the stability of the toe of the subgrade structure 100 can be effectively enhanced. By adopting a multi-level and multi-layer retaining wall method on the base course 10, the problem of insufficient stability of the filled subgrade is improved. Moreover, the structure of the multi-layer retaining wall can adapt to a higher height than ordinary retaining walls, and is more suitable for the construction of high-filled subgrades. Compared with the ultra-large cross-section super-high retaining walls, the stability of the subgrade structure 100 is improved, and the use of a multi-level retaining wall form can save masonry work, is safer in structure, and more economical. More importantly, in this solution, the subgrade adopts a slope protection 13 and a multi-layer retaining wall structure, which lays a foundation for the lateral connection of the road bridge, enabling the side beam 80 of the bridge 102 to be constructed by means of lateral connection with the retaining wall of the subgrade, and solving the problems of difficult lateral connection and poor stability between the road 101 project and the bridge 102 project.

[0040] It should be noted that the bridge 102 can be a long continuous beam. The bridge can include multiple sub-beams in its width direction. Among them, the outermost sub-beam can be called the side beam 80, and the side beam 80 mentioned in this embodiment is actually the sub-beam of the bridge 102 close to the road subgrade.

[0041] In some embodiments, the slope protection 13 in the base course 10 can be a shotcrete slope protection, a grid-frame vegetation slope protection, or a counterweight slope protection, etc.

[0042] Taking the counterweight slope protection as an example, a grass and shrub protection layer is provided on the slope surface of the counterweight slope protection.

[0043] By the plant roots in the grass and shrub protection layer extending into the soil body of the slope protection 13, it plays a role in stabilizing the soil body of the slope protection 13. Correspondingly, the stability of the slope surface of the slope protection 13 can be improved, thereby improving the bearing performance of the slope protection 13, and at the same time, the aesthetics of the slope protection 13 is also improved.

[0044] The slope ratio of the counterweight slope protection can be 1:2, so that the slope of the slope surface of the slope protection 13 is moderate, and a good buffering effect is exerted on the toe of the subgrade.

[0045] In some embodiments, with continued reference to Figure 1 , the subgrade structure 100 may further include a first slope protection platform 20 and / or a second slope protection platform 50.

[0046] Among them, the first slope protection platform 20 is provided at the top of the base course 10 and is located horizontally between the slope protection 13 and the lowermost retaining wall among the multiple retaining walls.

[0047] By constructing the first slope protection platform 20 between the slope protection 13 and the lowermost retaining wall, the first slope protection platform 20 can effectively prevent rainwater from penetrating into the base course and avoid the influence of rainwater infiltration on the overall stability of the base course.

[0048] In some embodiments, the first slope protection platform 20 may be a concrete cushion, cement mortar, or dry-laid rubble masonry, etc.

[0049] Taking the first slope protection platform 20 as dry-laid rubble masonry as an example, the width of the first slope protection platform 20 may be not less than 3 m, and the surface is protected by dry-laid rubble masonry with a thickness of 35 cm of M7.5.

[0050] The dry-laid rubble masonry protection can effectively prevent rainwater from infiltrating into the base course or the backfill layer and ensure the stability of the subgrade.

[0051] The first slope protection platform 20 may have an inclined slope towards the slope protection 13, and the inclined slope may be 3%.

[0052] In the case where a grass and shrub protection layer is provided on the slope surface of the slope protection 13 and the first slope protection platform 20 may have an inclined slope of 3% towards the slope protection 13, the accumulated water on the platform can be effectively drained through the first slope protection platform 20 and diverted to the grass and shrub protection layer on the slope surface of the slope protection 13 for plants to absorb.

[0053] The second slope protection platform 50 is provided at the top of the backfill layer and is located horizontally between two adjacent retaining walls among the multiple retaining walls, so that the upper retaining wall is farther away from the slope protection 13 horizontally than the lower retaining wall.

[0054] By constructing the second slope protection platform 50 at the top of the backfill layer and between the upper and lower adjacent retaining walls, it can effectively prevent rainwater from infiltrating into the backfill layer and effectively improve the problem of insufficient stability of the high-fill subgrade. In addition, the second slope protection platform 50 can provide an inspection passage for the bridge 102 girders during the operation period, facilitating the inspection and maintenance of the bridge 102.

[0055] In some embodiments, the second slope protection platform 50 may also be a concrete cushion, cement mortar, or dry-laid rubble masonry, etc.

[0056] Taking the second slope protection platform 50 made of dry rubble masonry as an example, the width of the second slope protection platform 50 can be not less than 3m, and the surface is protected by dry rubble masonry with a thickness of 35cm and grade M7.5.

[0057] The protection of dry rubble masonry can effectively prevent rainwater from infiltrating into the base layer or backfill layer, ensuring the stability of the roadbed.

[0058] The second slope protection platform 50 can have a slope towards the slope 13, and the slope can be 3%.

[0059] When the second slope protection platform 50 has a slope towards the slope 13, the second slope protection platform 50 can guide the water discharged from the retaining wall downwards along multiple retaining walls to the first slope protection platform 20 in sequence, and finally discharge it into the grass and shrub protection layer on the slope 13 surface.

[0060] In some embodiments, the backfill soil of the backfill layer can be plain soil, sandy soil, or a mixture of soil and rock, etc.

[0061] Taking the backfill soil as a mixture of soil and rock, compared with conventional plain soil, the mixture of soil and rock has higher strength, so that the bearing capacity of the foundation of the backfill layer is correspondingly greater, and it can better resist the deformation of the roadbed.

[0062] Specifically, when backfilling with the mixture of soil and rock, it can be backfilled in layers, and the backfill soil of each layer is tamped step by step in sequence.

[0063] In some embodiments, the retaining wall can be a gravity retaining wall, a cantilever retaining wall, or a counterfort retaining wall, etc. Figure 3 The case where the retaining wall is a cantilever retaining wall is exemplarily shown.

[0064] The cantilever retaining wall is a reinforced concrete structure, and the concrete of the retaining wall can be C25, C30, or C40, etc. The cantilever retaining wall can adapt to relatively soft foundations, and the wall height is generally between 6m and 9m. Please refer to Figure 3 , the cantilever retaining wall is composed of a bottom slab 31 and a wall body 32 fixed on the bottom slab 31, and it is a retaining wall that mainly relies on the weight of the fill on the bottom slab 31 to maintain stability.

[0065] Among them, the buried depth of the bottom slab 31 of the retaining wall is not less than 1m, and at least 50cm thick crushed stone cushion layer can be tamped at the bottom of the retaining wall to maintain the stability of the retaining wall.

[0066] In some embodiments, please refer to Figure 3 , a plurality of drainage holes 321 are provided on the wall body 32, and the drainage holes 321 penetrate through the wall body 32 along the thickness direction of the wall body 32.

[0067] By providing a plurality of drainage holes 321 on the wall body 32, the accumulated water in the backfill layer can be effectively drained, thereby preventing the accumulated water from being accumulated in the backfill layer for a long time and causing the water level in the backfill layer to be too high, thereby affecting the stability of the backfill soil in the backfill layer.

[0068] The plurality of drainage holes 321 may have a slope in the wall body 32 so as to effectively drain the accumulated water in the backfill layer.

[0069] In some embodiments, a gravel filter layer 33 is provided between the wall body 32 of the retaining wall and the backfill layer.

[0070] The gravel filter layer 33 can effectively filter the accumulated water in the backfill layer inside the retaining wall to prevent the backfill from being discharged from the drainage holes 321, thereby avoiding the phenomenon that the overall stability of the roadbed structure 100 is affected by soil and water loss of the backfill in the roadbed.

[0071] The specific thickness of the gravel filter layer 33 can be determined according to actual conditions. The thickness of the gravel filter layer 33 can be 20 cm.

[0072] The gravel filter layer 33 can be graded crushed stone and pebbles. By combining pebbles and graded crushed stone, the soil in the backfill layer can be prevented from being lost to a large extent, and the flowability of the water in the backfill layer can be ensured.

[0073] In some embodiments, please refer to Figure 4 The roadbed structure 100 further includes a telescopic mechanism (not shown in the figure), which is connected to the uppermost retaining wall and the side beam 80. An expansion joint 90 is formed between the uppermost retaining wall and the side beam 80, and the telescopic mechanism is used to allow the uppermost retaining wall and the side beam 80 to be able to expand and contract along the width direction of the expansion joint 90.

[0074] By forming an expansion joint 90 between the uppermost retaining wall and the side beam 80 and effectively connecting them through a telescopic device, the deformation of the fill roadbed of the road 101 and the connecting side beam 80 can be coordinated, thereby ensuring the overall structural safety of the bridge 102, effectively alleviating the phenomenon of vehicle jumping at the bridge head, and ensuring a smooth connection between the bridge and the road.

[0075] Optionally, the telescopic device can be a Type 80 telescopic device.

[0076] In some embodiments, a cap 61 is provided on the top of the uppermost retaining wall, and the cap 61 is integrally cast with the uppermost retaining wall. Figure 4 2 shows a case where the uppermost retaining wall has a cap 61 .

[0077] In some embodiments, when a coping 61 is provided at the top of the uppermost retaining wall, a first groove 610 is provided on the side of the coping 61 close to the side beam 80, and a second groove 81 is provided on the side of the side beam 80 close to the coping 61; the first groove 610 and the second groove 81 cooperate to form a receiving groove for accommodating the expansion mechanism.

[0078] Part of the expansion mechanism is located in the uppermost retaining wall, and part of it is located in the side beam 80, thus forming a receiving space for the expansion mechanism, which can play a role in limiting the expansion mechanism and preventing the expansion mechanism from shifting. The uppermost retaining wall and the side beam 80 are effectively connected through the expansion mechanism, improving the connection stability of the expansion mechanism.

[0079] Among them, anchor bars are embedded in the first groove 610 and the second groove 81, facilitating the connection with the expansion mechanism. The first groove 610 of the coping 61 can be cast with C30 steel fiber concrete.

[0080] Second, the embodiment of the present application also provides a construction method for a subgrade structure 100 applicable to bridge-road connection. The construction method includes the following steps: Backfill the bottom of the slope of the subgrade and compact the backfill material to form a base layer 10 with a slope protection 13. Construct a plurality of backfill layers and a plurality of retaining walls on the base layer 10 from bottom to top. Among them, after constructing one retaining wall, one backfill layer is correspondingly constructed, so that each retaining wall is located on the side of the corresponding backfill layer close to the slope protection 13 in the horizontal direction, and the retaining wall located on the upper side is farther from the slope protection 13 in the horizontal direction than the retaining wall located on the lower side. Connect the uppermost retaining wall to the side beam 80 of the bridge 102.

[0081] In the above construction method, a slope protection 13 is first formed at the bottom of the slope of the base layer 10, which can effectively enhance the stability of the slope foot of the subgrade structure 100 while ensuring coordination with the surrounding environment. Then, the problem of insufficient stability of the filled subgrade is improved by adopting a step-by-step multi-layer retaining wall method on the base layer, and the structure of the multi-layer retaining wall can adapt to a higher height ratio than ordinary retaining walls, and is more suitable for the construction of high-filled subgrades. Compared with ultra-large cross-section super-high retaining walls, the stability of the subgrade structure 100 is improved, and the use of a multi-stage retaining wall form can save masonry work, is safer in structure, and more economical. More importantly, in this solution, the subgrade adopts a slope protection 13 and a multi-layer retaining wall structure, which lays a foundation for the lateral connection between the road and the bridge, enabling the side beam 80 of the bridge 102 to be laterally connected to the retaining wall of the subgrade, solving the problems of difficult lateral connection and poor stability between the road 101 project and the bridge 102 project.

[0082] In some embodiments, before backfilling the bottom of the slope of the subgrade, a stepped surface 12 can be excavated on the original steep slope 11. The width of the stepped surface 12 is not less than 2m, and the inward slope is 2%.

[0083] In this way, the stepped surface 12 of the original steep slope 11 can improve the stabilizing ability for the subsequent backfill layer, avoiding the overall downward lateral movement of the backfill layer along the inclined direction of the slope surface, which may lead to the instability of the backfill layer.

[0084] When constructing the slope protection 13 of the base layer, the process of counterweight slope protection can be adopted. For counterweight slope protection, the mixture of soil and stone should be backfilled in layers and compacted densely. The specific height can be determined or adjusted according to the on-site conditions. After the slope surface of the counterweight slope protection 13 is leveled, mechanical hydraulic spraying and seeding of grass and shrubs are used for greening, and non-woven fabric is covered for maintenance until the lawn is formed.

[0085] The specific number of retaining walls can be determined according to the actual on-site conditions. In this embodiment, Figure 2 exemplarily shows a structural form in which the subgrade structure 100 includes two layers of retaining walls.

[0086] The following takes the construction of two layers of retaining walls as an example for illustration:

[0087] When constructing the first retaining wall 30, first, at the top of the base layer 10 and in the direction close to the first slope protection platform 20, arrange the steel bars of the bottom plate 31 and the wall body 32 of the first retaining wall 30, and then formwork the bottom plate 31 and pour the concrete of the bottom plate 31. The concrete pouring of the bottom plate 31 should be completed at one time without interruption in the width direction. After the concrete strength of the bottom plate 31 of the first retaining wall 30 reaches 2.5 MPa, the top surface is roughened and the residues are removed. Subsequently, formwork the wall body 32, arrange the drain holes 321, and pour the concrete of the wall body 32. After the wall body 32 of the first retaining wall 30 reaches 75% of the design strength, carry out the construction of the first backfill layer 40. After the first backfill layer 40 is tamped, construct the second slope protection platform 50 on its surface. After the second slope protection platform 50 is constructed, similarly, construct the second retaining wall 60. The technological steps of the second retaining wall 60 are substantially the same as those of the first retaining wall 30. In the case of having a coping 61, the coping 61 is integrally cast with the second retaining wall 60. After the construction of the second retaining wall 60 is completed, backfill the second backfill layer 70 behind the wall, and the backfill should be carried out in layers.

[0088] In the above process, through the first slope protection platform 20, the retaining wall can effectively prevent rainwater from infiltrating and divert the rainwater to the slope surface of the slope protection 13. By constructing the second slope protection platform 50 on the top of the backfill layer and between the upper and lower adjacent retaining walls, it can effectively prevent rainwater from infiltrating into the backfill layer, effectively improving the problem of insufficient stability of the high-fill subgrade. In addition, the second slope protection platform 50 can provide an inspection passage for the beam slabs of the bridge 102 during the operation period, facilitating the inspection and maintenance of the bridge 102.

[0089] It should be noted that, without conflict, the features in the embodiments of the present application can be combined with each other.

[0090] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A subgrade structure applicable to bridge connection, characterized in that, Comprising: A bridge, including side girders located on one side in its width direction; A roadbed, including a base course, a plurality of backfill layers, and a plurality of retaining walls. The base course has a slope protection, and the plurality of backfill layers are sequentially arranged on the base course from bottom to top. One retaining wall is provided on one side of each backfill layer close to the slope protection in the horizontal direction. Among every two adjacent retaining walls, the upper retaining wall is farther away from the slope protection than the lower retaining wall in the horizontal direction; A first slope protection platform, provided on the top of the base course and located between the slope protection and the lowermost retaining wall among the plurality of retaining walls in the horizontal direction; A second slope protection platform, provided on the top of the backfill layer and located between two adjacent retaining walls among the plurality of retaining walls in the horizontal direction, so that the upper retaining wall is farther away from the slope protection than the lower retaining wall in the horizontal direction; Wherein, the uppermost retaining wall among the plurality of retaining walls is connected to the side girder.

2. The subgrade structure applicable to bridge connection according to claim 1, characterized in that, The roadbed structure further includes: An expansion mechanism, connected between the uppermost retaining wall and the side girder; an expansion joint is formed between the uppermost retaining wall and the side girder, and the expansion mechanism is used to allow the uppermost retaining wall and the side girder to undergo expansion and contraction deformation along the width direction of the expansion joint.

3. The subgrade structure applicable to bridge connection according to claim 2, characterized in that A first groove is provided on one side of the uppermost retaining wall among the plurality of retaining walls close to the side girder, and a second groove is provided on one side of the side girder close to the uppermost retaining wall among the plurality of retaining walls; the first groove and the second groove cooperate to form a receiving groove for accommodating the expansion mechanism.

4. The subgrade structure applicable to bridge connection according to claim 1, characterized in that, The retaining wall includes a bottom plate and a wall body, the bottom plate and the wall body are connected, and the wall body is provided with a plurality of drainage holes, and the drainage holes penetrate through the wall body along the thickness direction of the wall body.

5. The subgrade structure applicable to bridge connection according to claim 4, characterized in that, A gravel filter layer is provided between the wall body of the retaining wall and the backfill layer.

6. A construction method for a subgrade structure suitable for bridge-road connection, based on the subgrade structure suitable for bridge-road connection according to any one of claims 1-5, characterized in that, Including the following steps: Backfill the slope bottom of the roadbed, and compact the backfill material to form a base course with a slope protection; Construct a plurality of backfill layers and a plurality of retaining walls on the base course from bottom to top. Among them, after constructing one retaining wall, one backfill layer is correspondingly constructed, so that each retaining wall is located on one side of the corresponding backfill layer close to the slope protection in the horizontal direction, and the upper retaining wall is farther away from the slope protection than the lower retaining wall in the horizontal direction; Connect the uppermost retaining wall to the side girder of the bridge; Before constructing the lowermost retaining wall, construct a first slope protection platform on the top of the base course, so that the first slope protection platform is located between the slope protection and the lowermost retaining wall among the plurality of retaining walls; During the process of constructing two adjacent retaining walls, before constructing the upper retaining wall on the backfill layer, construct a second slope protection platform on the top of the backfill layer, so that the second slope protection platform is located between two adjacent retaining walls among the plurality of retaining walls.

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