High soil retaining wing wall type bridge abutment system

Abstract

The invention relates to the technical field of crossing of hydraulic engineering and bridge engineering, and discloses a high soil retaining wing wall type bridge abutment system which comprises a flat pressing type empty box buttress type supporting and retaining structure, a three-dimensional drainage system and a U-shaped foundation trench wrapped light filler structure. The flat pressing type empty box buttress type retaining structure serves as a main body bearing structure of the abutment system. The three-dimensional drainage system is arranged in a backfill area of the flat pressing type empty box buttress type retaining structure; the U-shaped foundation trench wrapping light filler structure is arranged above the three-dimensional drainage system and located on the rear side of the flat pressing type empty box buttress type supporting and retaining structure so as to replace a part of backfill soil. The flat pressing type empty box buttress type supporting and retaining structure, the three-dimensional drainage system and the U-shaped foundation trench wrapped light filler structure are closely connected in space and synergistically act functionally, and the comprehensive effects of reducing structural load, optimizing stress distribution and improving overall stability are jointly achieved.

Description

Technical Field

[0001] This invention relates to the technical field of interdisciplinary engineering of water conservancy and bridge engineering, specifically to a high retaining wall bridge abutment system. Background Technology

[0002] In water conservancy projects, the abutments of bridges near rivers often adopt the form of wing walls that also serve as retaining structures. Such structures need to withstand multiple loads simultaneously, including river water pressure, soil and water pressure behind the wall (abutment back), uplift pressure at the foundation, lane loads, and loads transmitted from the bridge superstructure. Their stability directly determines the safe operation of water conservancy facilities and traffic bridges.

[0003] However, under conditions of high retaining walls with a retaining height of not less than 15m and heavy loads, traditional technical solutions have significant drawbacks, specifically as follows:

[0004] Excessive structural self-weight leads to foundation bearing failure: Traditional gravity concrete bridge abutments typically achieve structural stability by increasing cross-sectional dimensions to meet overturning resistance requirements. For example, a gravity bridge abutment with a retaining height of 18m can have a self-weight of 800–1200 kN / m, resulting in peak base stress of 250–350 kPa; while the bearing capacity of soft soil foundations generally does not exceed 200 kPa, making it extremely easy for base stress to exceed the limit.

[0005] The superposition of water and soil pressures leads to structural instability: In riverside environments, the backfill soil behind the wall is highly saturated, easily creating a coupling effect of hydrostatic pressure, seepage pressure, and buoyancy. For every 1m rise in the groundwater level, a lateral pressure of 10kPa will be generated per unit area; under extreme rainstorm conditions, the groundwater level behind the wall can rise suddenly by 3-5m, further exacerbating the superposition effect of loads.

[0006] Currently, the localized improvement measures implemented within the industry to address the aforementioned issues are insufficient to create a systemic synergistic effect, as detailed below:

[0007] While the empty box weight reduction scheme can reduce the structural weight by 20% to 25%, the lack of water level balance and pressure equalization measures inside and outside the empty box makes the difference in water head inside and outside prone to buoyancy risks, and it cannot solve the problem of water pressure behind the wall. In addition, traditional drainage schemes mostly use single-layer planar drainage pipes, which are insufficient for controlling deep seepage in high fill soil. Calculation data shows that when the retaining height is >12m, its reduction rate of pore water pressure at the wall foot is less than 30%. The local application of lightweight fill material has limited pressure reduction effect because it does not cover the main soil pressure area.

[0008] In summary, existing technical solutions cannot systematically address the stability issues of wing-wall abutments with a retaining height of not less than 15m and under heavy load conditions. There is an urgent need for a synergistic technical system that integrates structural self-weight optimization, three-dimensional drainage and pressure reduction, and lightweight filling to fundamentally solve the system stability problem of wing-wall abutments with high retaining walls. Summary of the Invention

[0009] In view of this, the present invention provides a high retaining wall bridge abutment system to solve the above-mentioned problems.

[0010] This invention provides a high retaining wall bridge abutment system, comprising:

[0011] The flat-pressure type empty box buttress support structure serves as the main load-bearing structure of the bridge abutment system.

[0012] A three-dimensional drainage system is installed within the backfill area behind the wall of the flat-pressure type hollow box buttress retaining structure; and

[0013] The U-shaped trench encloses a lightweight filler structure, which is positioned above the three-dimensional drainage system and behind the flat-pressure type hollow box buttress support structure to replace part of the backfill soil.

[0014] In one optional embodiment, the flat-pressure type empty box buttress support structure includes a bottom plate, a front wall, a rear wall, a partition wall, a buttress, a top plate, and an ear wall.

[0015] The lower part of the front wall and partition wall is provided with a leveling hole for connecting the water levels inside and outside the empty box, and the center elevation of the leveling hole is lower than the lowest water level of the river.

[0016] The rear wall is provided with drainage holes for draining groundwater behind the wall, and the drainage holes are arranged in layers at intervals along the back of the rear wall.

[0017] The upper part of the front wall is provided with a vent for balancing the air pressure inside and outside the empty box, and the center elevation of the vent is higher than the highest water level of the river.

[0018] This high retaining wall abutment system comprises a flat-pressure type hollow box buttress support structure, a three-dimensional drainage system, and a U-shaped trench-wrapped lightweight fill structure. The flat-pressure type hollow box buttress support structure, as the main load-bearing structure of the abutment system, significantly reduces its self-weight through its internal cavity design and provides core support for the entire abutment system through its overall rigidity and stability. The three-dimensional drainage system is located within the backfill area behind the flat-pressure type hollow box buttress support structure. Through a three-dimensional, interwoven pipe network, it efficiently collects and rapidly drains seepage water from the backfill, thereby significantly reducing the hydrostatic and seepage pressures acting on the back of the flat-pressure type hollow box buttress support structure. The U-shaped trench-wrapped lightweight fill structure is located above the three-dimensional drainage system and behind the flat-pressure type hollow box buttress support structure, replacing part of the backfill. This structure, through its internal lightweight filling material, significantly reduces the weight of the backfill, thereby directly reducing the active earth pressure acting on the flat-pressure type hollow box buttress support structure.

[0019] The flat-pressure type empty box buttress support structure, three-dimensional drainage system and U-shaped foundation trench wrapped lightweight filler structure are closely connected in space and work synergistically in function, together achieving the comprehensive effect of reducing structural load, optimizing stress distribution and improving overall stability.

[0020] In one optional implementation, the three-dimensional drainage system includes:

[0021] Multi-layered horizontally reinforced flexible permeable pipes are buried in layers in the backfill soil behind the wall;

[0022] Multiple vertical, flat plastic drainage ditches are spaced apart and installed close to the back of the rear wall, with their placement corresponding to the drainage holes; and

[0023] Multiple horizontally reinforced flexible permeable pipes connect the horizontally reinforced flexible permeable pipes to the vertical flat plastic drainage blind ditch, together forming a three-dimensional drainage network.

[0024] The lower part of the front wall and partition walls is equipped with leveling holes to connect the water levels inside and outside the empty box. The center elevation of the leveling holes is lower than the lowest water level of the river. Through the free flow of water, the water pressure inside and outside the empty box is dynamically balanced, effectively reducing the uplift pressure on the foundation and the buoyancy force of the structure caused by the water level difference. The rear wall is equipped with drainage holes to drain groundwater behind the wall. The drainage holes are arranged in layers along the back of the rear wall. The effect is that groundwater in the backfill soil behind the wall can be directly introduced into the cavity inside the empty box, thereby significantly reducing the hydrostatic pressure and seepage pressure acting on the rear wall and enhancing the structure's anti-slip and anti-overturning stability. The upper part of the front wall is equipped with vents to balance the air pressure inside and outside the empty box. The center elevation of the vents is higher than the highest water level of the river, ensuring that the cavity inside the empty box is connected to the atmosphere. This prevents the formation of positive or negative pressure in the cavity due to drastic rises and falls in water level or temperature changes, thereby avoiding additional loads on the base plate, front wall, rear wall, partition walls and other components. The leveling holes, drainage holes, and ventilation holes work together to regulate and balance the external environmental forces acting on the flat-pressure type hollow box buttress support structure, thereby improving its working performance and long-term safety under complex hydrogeological conditions near the river.

[0025] In one alternative embodiment, the horizontally reinforced flexible permeable pipe, the vertically flat plastic drainage blind ditch, and the transversely reinforced flexible permeable pipe are interconnected by a T-joint.

[0026] The T-joint provides a standardized connection point for horizontally reinforced flexible permeable pipes, vertically flat plastic drainage blind drains, and transversely reinforced flexible permeable pipes. It ensures that seepage water flowing in the horizontally reinforced flexible permeable pipe can be efficiently channeled into the transversely reinforced flexible permeable pipe, and then smoothly introduced into the vertically flat plastic drainage blind drain through the T-joint, ultimately forming a continuous drainage path.

[0027] In one optional embodiment, the U-shaped groove encapsulating lightweight filler structure includes:

[0028] The U-shaped foundation trench consists of a bottom side plate and two side walls;

[0029] EPS lightweight filler is laid in layers with staggered joints within the U-shaped base trench;

[0030] A concrete cover layer, which covers the EPS lightweight filler; and

[0031] A stepped overlap surface is provided between the EPS lightweight filler and the adjacent conventional filler.

[0032] The U-shaped foundation trench, EPS lightweight filler, concrete cover layer, and stepped lap surface work together to achieve a comprehensive effect of reducing load, maintaining stability, and coordinating deformation.

[0033] In one optional embodiment, the length of the U-shaped trench is not less than the extension surface of the backfill fracture angle, and a drainage hole for draining water accumulated in the trench is provided at the bottom of its side wall.

[0034] The length of the U-shaped trench and the drainage holes work together to ensure that the lightweight filler structure wrapped in the U-shaped trench can effectively suppress soil damage from a macroscopic perspective and eliminate the risk of internal water accumulation from a detailed perspective, thus achieving a balance between structural stability and durability.

[0035] In one optional embodiment, the density of the EPS lightweight filler is 0.2-0.3 kN / m³. 3 The compressive strength is not less than 100 kPa, and the blocks of the EPS lightweight filler are connected and sealed with connectors and pins.

[0036] In one optional embodiment, the concrete cover layer is a fine aggregate concrete layer with a thickness of not less than 150 mm.

[0037] In one optional embodiment, the height difference of each step of the stepped overlap surface is 450mm-550mm, and its length extending into the adjacent conventional fill area is not less than 1.0m.

[0038] In one optional embodiment, the diameter of the leveling hole is 150-300mm, the diameter of the drain hole is 75-100mm, and the diameter of the vent hole is 100-150mm. Attached Figure Description

[0039] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 This is a structural schematic diagram of a high retaining wall bridge abutment system according to an embodiment of the present invention;

[0041] Figure 2 for Figure 1 Sectional view at point AA;

[0042] Figure 3 for Figure 1 Cross-sectional view at the middle BB;

[0043] Figure 4 for Figure 1 Sectional view at point CC.

[0044] Explanation of reference numerals in the attached figures:

[0045] 11. Base plate;

[0046] 12. Front wall;

[0047] 13. Rear wall;

[0048] 14. Partition wall;

[0049] 15. Supporting oneself against the wall;

[0050] 16. Top slab;

[0051] 17. Ear wall;

[0052] 18. Leveling hole;

[0053] 19. Drainage hole;

[0054] 20. Vent hole;

[0055] 21. Horizontally reinforced flexible permeable pipe;

[0056] 22. Vertical flat plastic drainage blind ditch;

[0057] 23. Horizontally reinforced flexible permeable pipe;

[0058] 24. U-shaped foundation trench;

[0059] 25. Lightweight filler for EPS;

[0060] 26. Concrete cover layer;

[0061] 27. Stepped lap joint surface;

[0062] 28. Drain hole. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] In water conservancy projects, the abutments of bridges near rivers often adopt the form of wing walls that also serve as retaining structures. Such structures need to withstand multiple loads simultaneously, including river water pressure, soil and water pressure behind the wall (abutment back), uplift pressure at the foundation, lane loads, and loads transmitted from the bridge superstructure. Their stability directly determines the safe operation of water conservancy facilities and traffic bridges.

[0065] However, under conditions of high retaining walls with a retaining height of not less than 15m and heavy loads, traditional technical solutions have significant drawbacks, specifically as follows:

[0066] Excessive structural self-weight leads to foundation bearing failure: Traditional gravity concrete bridge abutments typically achieve structural stability by increasing cross-sectional dimensions to meet overturning resistance requirements. For example, a gravity bridge abutment with a retaining height of 18m can have a self-weight of 800–1200 kN / m, resulting in peak base stress of 250–350 kPa; while the bearing capacity of soft soil foundations generally does not exceed 200 kPa, making it extremely easy for base stress to exceed the limit.

[0067] The superposition of water and soil pressures leads to structural instability: In riverside environments, the backfill soil behind the wall is highly saturated, easily creating a coupling effect of hydrostatic pressure, seepage pressure, and buoyancy. For every 1m rise in the groundwater level, a lateral pressure of 10kPa will be generated per unit area; under extreme rainstorm conditions, the groundwater level behind the wall can rise suddenly by 3-5m, further exacerbating the superposition effect of loads.

[0068] Currently, the localized improvement measures implemented within the industry to address the aforementioned issues are insufficient to create a systemic synergistic effect, as detailed below:

[0069] While the empty box weight reduction scheme can reduce the structural weight by 20% to 25%, the lack of water level balance and pressure equalization measures inside and outside the empty box makes the difference in water head inside and outside prone to buoyancy risks, and it cannot solve the problem of water pressure behind the wall. In addition, traditional drainage schemes mostly use single-layer planar drainage pipes, which are insufficient for controlling deep seepage in high fill soil. Calculation data shows that when the retaining height is >12m, its reduction rate of pore water pressure at the wall foot is less than 30%. The local application of lightweight fill material has limited pressure reduction effect because it does not cover the main soil pressure area.

[0070] In summary, existing technical solutions cannot systematically address the stability issues of wing-wall abutments with a retaining height of not less than 15m and under heavy load conditions. There is an urgent need for a synergistic technical system that integrates structural self-weight optimization, three-dimensional drainage and pressure reduction, and lightweight filling to fundamentally solve the system stability problem of wing-wall abutments with high retaining walls.

[0071] The following is combined with Figures 1 to 4 The following describes embodiments of the present invention.

[0072] According to an embodiment of the present invention, a high retaining wall bridge abutment system is provided, comprising a flat-pressure type hollow box buttress support structure, a three-dimensional drainage system, and a U-shaped trench-wrapped lightweight fill material structure. The flat-pressure type hollow box buttress support structure serves as the main load-bearing structure of the abutment system; the three-dimensional drainage system is located within the backfill area behind the flat-pressure type hollow box buttress support structure; the U-shaped trench-wrapped lightweight fill material structure is located above the three-dimensional drainage system and behind the flat-pressure type hollow box buttress support structure, replacing part of the backfill area.

[0073] This high retaining wall abutment system comprises a flat-pressure type hollow box buttress support structure, a three-dimensional drainage system, and a U-shaped trench-wrapped lightweight fill structure. The flat-pressure type hollow box buttress support structure, as the main load-bearing structure of the abutment system, significantly reduces its self-weight through its internal cavity design and provides core support for the entire abutment system through its overall rigidity and stability. The three-dimensional drainage system is located within the backfill area behind the flat-pressure type hollow box buttress support structure. Through a three-dimensional, interwoven pipe network, it efficiently collects and rapidly drains seepage water from the backfill, thereby significantly reducing the hydrostatic and seepage pressures acting on the back of the flat-pressure type hollow box buttress support structure. The U-shaped trench-wrapped lightweight fill structure is located above the three-dimensional drainage system and behind the flat-pressure type hollow box buttress support structure, replacing part of the backfill. This structure, through its internal lightweight filling material, significantly reduces the weight of the backfill, thereby directly reducing the active earth pressure acting on the flat-pressure type hollow box buttress support structure.

[0074] The flat-pressure type empty box buttress support structure, three-dimensional drainage system and U-shaped foundation trench wrapped lightweight filler structure are closely connected in space and work synergistically in function, together achieving the comprehensive effect of reducing structural load, optimizing stress distribution and improving overall stability.

[0075] In one embodiment, the flat-pressure type empty box buttress support structure includes a base plate 11, a front wall 12, a rear wall 13, a partition wall 14, a buttress 15, a top plate 16, and an abutment wall 17; the lower part of the front wall 12 and the partition wall 14 is provided with a leveling hole 18 for connecting the water levels inside and outside the empty box, and the center elevation of the leveling hole 18 is lower than the lowest water level of the river; the rear wall 13 is provided with a drainage hole 19 for draining groundwater behind the wall, and the drainage holes 19 are arranged in layers at intervals along the back of the rear wall 13; the upper part of the front wall 12 is provided with a vent 20 for balancing the air pressure inside and outside the empty box, and the center elevation of the vent 20 is higher than the highest water level of the river.

[0076] In this embodiment, the flat-pressure type empty box buttress support structure includes a bottom plate 11, a front wall 12, a rear wall 13, a partition wall 14, a buttress 15, a top plate 16, and an ear wall 17. These components together form a rigid whole with an internal cavity.

[0077] The lower part of the front wall 12 and partition wall 14 is provided with leveling holes 18 for connecting the water levels inside and outside the empty box. The center elevation of the leveling holes 18 is lower than the lowest water level of the river. Through the free flow of water, the water pressure inside and outside the empty box is dynamically balanced, effectively reducing the uplift pressure on the foundation and the buoyancy force of the structure caused by the water level difference. The rear wall 13 is provided with drainage holes 19 for draining groundwater behind the wall. The drainage holes 19 are arranged in layers along the back of the rear wall 13. The effect is that it can directly guide the groundwater in the backfill soil behind the wall into the cavity inside the empty box, thereby significantly reducing the hydrostatic pressure and seepage pressure acting on the rear wall 13 and enhancing the anti-slip and anti-overturning stability of the structure. The upper part of the front wall 12 is equipped with a vent 20 to balance the air pressure inside and outside the empty box. The center elevation of the vent 20 is higher than the highest water level of the river, ensuring that the cavity inside the empty box is connected to the atmosphere. This prevents the formation of positive or negative pressure in the cavity due to drastic rises and falls in water level or temperature changes, thereby avoiding additional loads on components such as the base plate 11, front wall 12, rear wall 13, and partition wall 14. The leveling hole 18, drainage hole 19, and vent 20 work together to regulate and balance the external environmental forces on the flat-pressure type empty box buttress support structure, improving its working performance and long-term safety under complex hydrogeological conditions near the river.

[0078] In one embodiment, the three-dimensional drainage system includes multiple layers of horizontally reinforced flexible permeable pipes 21, multiple vertically flat plastic drainage blind ditches 22, and multiple horizontally reinforced flexible permeable pipes 23. The multiple layers of horizontally reinforced flexible permeable pipes 21 are buried in layers in the backfill behind the wall. The multiple vertically flat plastic drainage blind ditches 22 are spaced apart and installed close to the back of the rear wall 13, and their laying positions correspond to the drainage holes 19. The horizontally reinforced flexible permeable pipes 23 connect the horizontally reinforced flexible permeable pipes 21 and the vertically flat plastic drainage blind ditches 22, together forming a three-dimensional drainage network.

[0079] Multi-layered horizontally reinforced flexible permeable pipes are buried in layers in the backfill behind the wall. Through their permeable walls, they efficiently collect and horizontally guide seepage water from backfill layers of different depths.

[0080] Multiple vertical flat plastic drainage blind ditches 22 are spaced apart and installed close to the back of the rear wall 13, and their installation positions correspond to the drainage holes 19, forming a vertical water collection channel close to the back of the wall. The collected groundwater is efficiently discharged into the cavity of the flat pressure type hollow box buttress support structure through the drainage holes 19, thereby directly reducing the hydrostatic pressure acting on the back of the wall.

[0081] The horizontally reinforced flexible permeable pipe 23 connects the horizontally reinforced flexible permeable pipe 21 and the vertical flat plastic drainage blind ditch 22, and transports the seepage water collected by the horizontally reinforced flexible permeable pipe 21 to the vertical flat plastic drainage blind ditch 22 horizontally, realizing the interconnection of drainage paths.

[0082] The horizontally reinforced flexible permeable pipe 21, the vertically oriented flat plastic drainage ditch 22, and the horizontally reinforced flexible permeable pipe 23 together form a highly efficient three-dimensional drainage network. This network, through the coordinated operation of horizontal collection, lateral transfer, and vertical guidance, intercepts, collects, and guides groundwater in the backfill soil behind the wall in a three-dimensional manner, significantly improving overall drainage efficiency, effectively controlling the groundwater level, greatly reducing the seepage pressure and lateral water pressure acting on the structure, and enhancing the stability of the bridge abutment system.

[0083] In one embodiment, the horizontally reinforced flexible permeable pipe 21, the vertically flat plastic drainage blind ditch 22, and the transversely reinforced flexible permeable pipe 23 are interconnected by a T-joint.

[0084] The T-joint provides a standardized connection point for the horizontally reinforced flexible permeable pipe 21, the vertically flat plastic drainage blind ditch 22, and the transversely reinforced flexible permeable pipe 23. It ensures that the seepage water flowing in the horizontally reinforced flexible permeable pipe 21 can be efficiently channeled into the transversely reinforced flexible permeable pipe 23, and smoothly introduced into the vertically flat plastic drainage blind ditch 22 through the T-joint, ultimately forming a continuous drainage path.

[0085] This connection method ensures the sealing and smooth flow of water within the entire three-dimensional drainage network, significantly reducing water flow resistance or leakage losses that may result from improper connections. This improves the overall drainage efficiency and reliability of the horizontally reinforced flexible permeable pipe 21, the vertically flat plastic drainage blind ditch 22, and the horizontally reinforced flexible permeable pipe 23 working together.

[0086] In one embodiment, the U-shaped trench-encased lightweight filler structure includes a U-shaped trench 24, EPS lightweight filler 25, a concrete cover layer 26, and a stepped overlap surface 27. The U-shaped trench 24 is composed of a bottom side plate and two side walls. The EPS lightweight filler 25 is laid in layers with staggered joints within the U-shaped trench 24. The concrete cover layer 26 covers the EPS lightweight filler 25. The stepped overlap surface 27 is provided between the EPS lightweight filler 25 and the adjacent conventional fill.

[0087] The U-shaped trench 24 is composed of a bottom side plate and two side walls, forming a rigid three-sided enclosure structure, which provides stable lateral restraint and bottom support for the internal EPS lightweight filler 25, effectively preventing it from displacing or becoming unstable under external forces.

[0088] EPS lightweight filler 25 is laid in staggered layers within the U-shaped foundation trench 24. Its extremely low density significantly reduces the total weight of the fill in this area, thereby directly reducing the active earth pressure acting on the bridge abutment structure. The staggered layering process ensures the integrity and uniform stress distribution of the filler layer.

[0089] The concrete cover layer 26 covers the EPS lightweight filler 25, providing a uniformly distributed surface load for the EPS lightweight filler 25 below, preventing it from being damaged by local pressure, and at the same time playing a role in waterproofing, preventing ultraviolet aging and fire protection.

[0090] The stepped overlap surface 27 is set between the EPS lightweight filler 25 and the adjacent conventional fill. The interlocking interface increases the shear resistance between the two, effectively coordinates the stiffness difference between the EPS lightweight filler 25 and the adjacent conventional fill area, prevents uneven settlement at the interface, and ensures the overall stability of the fill.

[0091] The U-shaped foundation trench 24, EPS lightweight filler 25, concrete cover layer 26, and stepped lap surface 27 work together to achieve a comprehensive effect of reducing load, maintaining stability, and coordinating deformation.

[0092] In one embodiment, the length of the U-shaped trench 24 is not less than the extension surface of the backfill fracture angle, and a drainage hole 28 for draining water accumulated in the trench is provided at the bottom of its side wall.

[0093] The length of the U-shaped trench 24 is not less than the extension surface of the backfill fracture angle. This ensures that the U-shaped trench wrapping lightweight filler structure can completely cover the area where the potential sliding surface of the soil behind the wall can develop. Thus, through the pressure reduction effect of the lightweight filler inside, it can effectively intervene in and block the development of the soil sliding surface, and significantly improve the overall stability of the backfill.

[0094] The bottom of the side wall of the U-shaped foundation trench 24 is provided with drainage holes 28 for draining water accumulated in the trench. This promptly removes water that may seep into or accumulate on the bottom side plate of the U-shaped foundation trench 24, effectively eliminating the hydrostatic pressure generated by the water in the trench on the side wall and bottom side plate of the U-shaped foundation trench 24, preventing adverse effects on the structure caused by factors such as water freezing and heave, and ensuring the durability and reliability of the U-shaped foundation trench 24 in long-term operation.

[0095] The length of the U-shaped trench 24 works in conjunction with the drainage hole 28 to ensure that the U-shaped trench encasing the lightweight filler structure can effectively suppress soil damage from a macroscopic perspective and eliminate the risk of internal water accumulation from a detailed perspective, thus achieving a balance between structural stability and durability.

[0096] In one embodiment, the density of the EPS lightweight filler 25 is 0.2-0.3 kN / m³. 3 The compressive strength is not less than 100kPa, and the blocks of EPS lightweight filler 25 are connected and sealed with connectors and pins.

[0097] The density of EPS lightweight filler 25 is 0.2-0.3 kN / m³. 3 It provides extremely low density, making its unit volume weight only 1 / 50 to 1 / 100 of that of conventional fill, thereby significantly reducing the total weight of the fill behind the wall and significantly reducing the dead load and earth pressure acting on the bridge abutment structure.

[0098] The EPS lightweight filler 25 has a compressive strength of not less than 100 kPa, which can withstand the vertical load transmitted from the overlying fill and concrete cover layer 26, ensuring that it will not undergo significant compression deformation during long-term use, and providing stable and reliable support for the superstructure.

[0099] The EPS lightweight filler 25 blocks are connected and sealed with connectors and pins, which firmly connects the individual EPS lightweight filler 25 blocks into a whole composite block with good integrity. This effectively enhances the overall shear strength and displacement resistance of the filler and prevents it from shifting or becoming unstable under lateral forces.

[0100] The low density, sufficient compressive strength, and reliable connection between the blocks of EPS lightweight filler 25 work together to ensure that the lightweight filler structure can maintain good structural stability and load-bearing performance while minimizing weight reduction, thus achieving a balance between pressure reduction and stability.

[0101] In one embodiment, the concrete cover layer 26 is a fine aggregate concrete layer with a thickness of not less than 150 mm.

[0102] The concrete cover layer 26 has a thickness of not less than 150mm, providing sufficient structural thickness and overall rigidity to effectively resist external loads and environmental influences. This thickness ensures that the concrete cover layer 26 has good load distribution capacity, enabling it to evenly transfer the upper load to the lower EPS lightweight filler 25, avoiding stress concentration that could cause localized damage.

[0103] The concrete cover layer 26 is made of fine aggregate concrete, which forms a continuous, complete, and waterproof protective shell through its unique dense structure and good workability. This material characteristic enables the concrete cover layer 26 to effectively prevent water seepage, prevent the EPS lightweight filler 25 from deteriorating due to water absorption, and also resist the aging effects of environmental factors such as ultraviolet radiation on the lightweight filler.

[0104] The concrete cover layer 26 serves as a robust protective layer, providing sufficient surface abrasion resistance and impact resistance to withstand construction equipment loads and possible external mechanical actions, ensuring the integrity and long-term performance of the underlying EPS lightweight filler 25.

[0105] The concrete cover layer 26, composed of a fine stone concrete layer with a thickness of not less than 150mm, provides sufficient protection for the underlying lightweight filler, ensures uniform load distribution and long-term durability, and provides a reliable working surface and protective interface for the entire lightweight filler structure.

[0106] In one embodiment, the height difference of each step of the stepped overlap surface 27 is 450mm-550mm, and its length extending into the adjacent conventional fill area is not less than 1.0m.

[0107] The stepped overlap surface 27 has a height difference of 450mm-550mm per step, for example, 500mm, forming a series of moderately high stepped transition interfaces. This specific height range ensures that the EPS lightweight filler 25 can establish an effective mechanical interlocking and interlocking effect with the adjacent conventional fill, providing sufficient contact area to enhance the shear resistance of the interface, while avoiding stress concentration problems that may be caused by excessive single-step height differences.

[0108] The stepped overlap surface 27 extends into the adjacent conventional fill area by a length of not less than 1.0m, providing a sufficiently long embedment and anchorage section. This minimum length ensures that the lateral earth pressure from the conventional fill area can be effectively transmitted and dispersed into the EPS lightweight filler block 25 through this length section, and vice versa, thereby coordinating the abrupt change in stiffness caused by the difference in materials on both sides and significantly reducing the risk of shear slip at the interface.

[0109] By controlling the elevation difference of each step to 450mm-550mm and coordinating it with an extension length of not less than 1.0m, the stepped overlap surface 27 works together to create a gradual transition zone with excellent mechanical properties between the EPS lightweight fill material 25 and the adjacent conventional fill. This structure effectively transfers and diffuses shear stress, minimizes uneven settlement caused by differences in material properties, ensures the integrity and stability of the fill, and provides a good drainage path.

[0110] In one embodiment, the diameter of the leveling hole 18 is 150-300mm, the diameter of the drain hole 19 is 75-100mm, and the diameter of the vent hole 20 is 100-150mm.

[0111] The orifice 18 has a diameter of 150-300mm, providing a sufficiently large cross-sectional area for water flow, ensuring rapid water exchange and water level balance between the river channel and the interior of the empty tank. This orifice diameter range can effectively balance the water pressure difference caused by water level fluctuations on the inside and outside of the empty tank, significantly reducing the unbalanced load acting on the structure.

[0112] The drainage hole 19 has a diameter of 75-100mm, which efficiently drains the groundwater flowing into the cavity from behind the wall. This diameter ensures sufficient drainage capacity to reduce the water pressure behind the wall in a timely manner, while also preventing excessive weakening of the structural strength of the rear wall 13 due to an excessively large opening.

[0113] The vent 20 has a diameter of 100-150mm, providing ample airflow area and ensuring smooth air pressure communication between the internal cavity of the empty box and the atmosphere. This vent diameter range effectively prevents airlocks or vacuum negative pressure from forming in the cavity due to drastic changes in water level or temperature effects, thereby preventing additional air pressure loads on the front wall 12 and the overall structure.

[0114] The specific aperture configuration of the leveling hole 18, drainage hole 19 and ventilation hole 20 works together to ensure the efficient and reliable realization of functions such as water level balance, groundwater discharge and air pressure balance, and optimizes the stress performance of the flat pressure type empty box buttress support structure in complex hydrological environment.

[0115] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A high retaining wall bridge abutment system, characterized in that, include: The flat-pressure type empty box buttress support structure serves as the main load-bearing structure of the bridge abutment system. A three-dimensional drainage system is installed within the backfill area behind the wall of the flat-pressure type hollow box buttress retaining structure; and The U-shaped trench encloses a lightweight filler structure, which is positioned above the three-dimensional drainage system and behind the flat-pressure type hollow box buttress support structure to replace part of the backfill soil.

2. The high retaining wall bridge abutment system according to claim 1, characterized in that, The flat-pressure type empty box buttress support structure includes a bottom plate (11), a front wall (12), a rear wall (13), a partition wall (14), a buttress (15), a top plate (16), and an ear wall (17); The lower part of the front wall (12) and the partition wall (14) is provided with a leveling hole (18) for connecting the water levels inside and outside the empty box. The center elevation of the leveling hole (18) is lower than the lowest water level of the river. The rear wall (13) is provided with drainage holes (19) for draining groundwater behind the wall. The drainage holes (19) are arranged in layers at intervals along the back of the rear wall (13). The upper part of the front wall (12) is provided with a vent (20) for balancing the air pressure inside and outside the empty box, and the center elevation of the vent (20) is higher than the highest water level of the river.

3. The high retaining wall bridge abutment system according to claim 2, characterized in that, The three-dimensional drainage system includes: Multi-layer horizontal reinforced flexible permeable pipe (21) is buried in layers in the backfill soil behind the wall; Multiple vertical, flat plastic drainage blind drains (22) are spaced apart and installed close to the back of the rear wall (13), with their installation positions corresponding to the drainage holes (19); and Multiple horizontally reinforced flexible permeable pipes (23) connect the horizontally reinforced flexible permeable pipes (21) and the vertical flat plastic drainage blind ditch (22) to form a three-dimensional drainage network.

4. The high retaining wall bridge abutment system according to claim 3, characterized in that, The horizontally reinforced flexible permeable pipe (21), the vertically flat plastic drainage blind ditch (22), and the transversely reinforced flexible permeable pipe (23) are interconnected by a T-joint.

5. The high retaining wall bridge abutment system according to claim 1, characterized in that, The U-shaped groove-enclosed lightweight filler structure includes: U-shaped trench (24), which consists of bottom side plate and two side walls; EPS lightweight filler (25) is laid in layers with staggered joints in the U-shaped base trench (24); A concrete cover layer (26) covering the EPS lightweight filler (25); and A stepped overlap surface (27) is provided between the EPS lightweight filler (25) and the adjacent conventional filler.

6. The high retaining wall bridge abutment system according to claim 5, characterized in that, The length of the U-shaped trench (24) is not less than the extension surface of the backfill fracture angle, and a drainage hole (28) is provided at the bottom of its side wall for draining water accumulated in the trench.

7. The high retaining wall bridge abutment system according to claim 5, characterized in that, The density of the EPS lightweight filler (25) is 0.2-0.3 kN / m³. 3 The compressive strength is not less than 100 kPa, and the blocks of the EPS lightweight filler (25) are connected and sealed with connectors and pins.

8. The high retaining wall bridge abutment system according to claim 5, characterized in that, The concrete cover layer (26) is a fine stone concrete layer with a thickness of not less than 150 mm.

9. The high retaining wall bridge abutment system according to claim 5, characterized in that, The height difference of each step of the stepped lap joint (27) is 450mm-550mm, and its length extending into the adjacent conventional fill area is not less than 1.0m.

10. The high retaining wall bridge abutment system according to claim 2, characterized in that, The diameter of the leveling hole (18) is 150-300mm, the diameter of the drain hole (19) is 75-100mm, and the diameter of the vent hole (20) is 100-150mm.

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