Bridgehead bump control road-bridge transition structure and construction method
By setting up a multi-layered protective structure between the roadbed and the bridge abutment, and using earth pressure gauges to monitor and automatically adjust the grouting and jacking systems, the problem of bridge approach slab settlement was solved, achieving effective control of bridge approach slab settlement and improving construction efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2023-06-29
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies struggle to effectively address the issue of bridge approach slab slab settlement, especially as slabs age and are prone to breakage, detachment from the bottom, or warping, resulting in poor anti-slab settlement performance and impacting driving safety.
Multi-layered protection measures are adopted, including the installation of U-shaped bearing platforms, expansion joints, buffer materials, steel piles, and grouting and jacking systems controlled by earth pressure gauges between the roadbed and bridge abutments. Settlement is monitored and automatically adjusted by earth pressure gauges, and foundation consolidation and jacking are carried out using lime slurry and expansive cement.
It effectively prevents differential settlement of the roadbed, reduces bridge approach slab settlement, ensures driving safety, and is simple and efficient to construct, enabling timely handling of settlement issues.
Smart Images
Figure CN116695553B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of road and bridge technology, specifically to a road and bridge transition structure and construction method for controlling bridge approach slab settlement. Background Technology
[0002] Because the stiffness of the roadbed is much less than that of the bridge structure, differential settlement occurs between the roadbed and the abutments under vehicle loads, altering the road surface smoothness. This leads to the phenomenon of "bridge approach slab settlement" when vehicles travel on this section of road. The main causes of bridge approach slab settlement include: differences in road and bridge stiffness, loss of roadbed fill material, design flaws, and substandard construction quality. Bridge approach slab settlement poses serious dangers, such as affecting vehicle speed and comfort, damaging highways and bridges, and increasing highway operation and maintenance costs. Therefore, with the increase in traffic volume and load capacity in my country, solving the problem of bridge approach slab settlement has become increasingly important.
[0003] In existing technologies, roadbed settlement is generally controlled by setting up slabs. However, as the service time increases, the slabs often break, the bottom of the slabs becomes hollow, or the slabs warp due to aging. This results in poor prevention of vehicle bounce and new defects such as secondary vehicle bounce, which is detrimental to driving safety and fails to achieve the expected results. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a road-bridge transition structure and construction method for controlling bridge approach slab settlement. In response to the bridge approach slab settlement problem, a variety of treatment measures are adopted to provide comprehensive and multi-layered protection for the foundation roadbed, approach slab, and abutment to avoid large differential settlement.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0006] A road-bridge transition structure for controlling bridge approach slab settlement is used to connect the roadbed and the abutment. The abutment body serves as the boundary, with the roadbed side on the left and the abutment side on the right. A convex-shaped support is provided on the top of the abutment body. The right side of the support supports the beam body through a bearing, while the left side of the support supports the approach slab. A groove is provided at the bottom of the approach slab, and an expansion joint system is installed in the groove.
[0007] The roadbed structure consists of, from bottom to top, the foundation roadbed, hard soil layer, crushed stone layer, and asphalt cover layer. Several steel piles are embedded inside the foundation roadbed, and several grouting pipes pass through the asphalt cover layer, crushed stone layer, and hard soil layer sequentially from the ground to enter the foundation roadbed. They are embedded at the top and bottom of the steel piles. The grouting pipes are equipped with signal-controlled ball valves, which are connected to earth pressure gauges. The ball valves are opened and closed by the signal output from the earth pressure gauges. After the ball valves open automatically, they release the lime slurry inside the grouting pipes to consolidate the soil in the area.
[0008] The basic roadbed is equipped with a roadbed lifting system, including a lower trough and an upper cover plate that are connected by an insertion joint. The feed pipe passes through the upper cover plate from the top and pours expansive cement into the lower trough. The water inlet pipe passes through the lower trough from the bottom and sprays water mist that combines with the expansive cement to form a solid, lifting the upper cover plate and thus compensating for the settlement of the roadbed. The lower trough is equipped with a pile insertion slot for insertion and fixation with steel piles.
[0009] The subgrade is covered with a hard soil layer, which is then covered with a crushed stone layer. The crushed stone layer is connected to the approach slab by a sloping joint. An asphalt cover layer is laid on top of the crushed stone layer.
[0010] More preferably, several support beams are vertically fixed in the groove at the bottom of the slab. The support beams divide the groove into several intervals. A buffer spring is placed in each interval. The top of the buffer spring is provided with a buffer pad and is tightly connected to the inner wall of the groove, so that the spring is under stress.
[0011] More preferably, the right end face of the approach slab and the corresponding left end face of the foundation are both covered with cushioning material, and concrete is poured into the gap between them.
[0012] More preferably, the earth pressure gauge is embedded at the center of several steel piles in the foundation subgrade. The earth pressure gauge is connected to the signal control ball valve and the signal receiver located on the asphalt cover layer via a signal line. The outside of the signal control ball valve is equipped with a ball valve protection box. The ball valve protection box is made of perforated thin steel plate with a perforation diameter of 0.5mm. A reverse osmosis membrane is pasted on the perforated thin steel plate. This membrane only allows liquid to flow out and does not allow soil particles to enter. This ensures that the lime slurry can be discharged smoothly and prevents soil particles from entering the box, thus protecting the signal control ball valve.
[0013] More preferably, the roadbed lifting system includes a lower trough and an upper cover plate; the lower trough includes a baffle, a pile insertion slot, and a positioning hole, the pile insertion slot is fixedly connected to the baffle, and the pile insertion slot is used to engage with steel piles; the baffle divides the lower trough into several small spaces; the upper cover plate includes a movable cover plate, a pile insertion hole, and a positioning sheath, the positioning sheath engages with the positioning hole, covering the lower trough with the upper cover plate, and making the pile insertion hole overlap with the pile insertion slot; the movable cover plate is hinged to the upper cover plate or rotatably connected through a central shaft, and its number is consistent with the number of several small spaces inside the lower trough, and it can completely cover the corresponding small space, and the movable cover plate can be opened when subjected to external force; the upper part of the movable cover plate is provided with a feed pipe interface, and the feed pipe interface is positioned corresponding to the water inlet interface of the lower trough.
[0014] More preferably, the water inlet pipe is laid from the ground into the foundation subgrade and connected to the various small spaces of the lower trough of the lifting system through the water inlet pipe interface at the bottom of the lower trough. The water inlet pipe is made of stainless steel.
[0015] A construction method for a road-bridge transition structure for controlling bridge approach slab settlement includes the following steps:
[0016] Step 1: Install the bridge abutment body and pier cap, and install the supports and beams on the right side of the pier cap. Construct the expansion joint system on the left side of the pier cap.
[0017] Step 2: When constructing the foundation roadbed, bury the grout inlet pipe, water inlet pipe, signal control ball valve and earth pressure gauge in the roadbed respectively. The signal control ball valve is connected to the earth pressure gauge, and the opening and closing of the ball valve is controlled by the signal output by the earth pressure gauge.
[0018] Step 3: Install the roadbed lifting system. First, place the constructed lower trench on the paved roadbed and connect the water inlet pipe. Insert the pile slots and steel piles into the trench and fix them in place. Connect the feed pipe to the lower trench. After installation, cover the lower trench with the upper cover plate.
[0019] Step 4: Continue laying the roadbed and install the grout inlet pipe, signal control ball valve and earth pressure gauge in sequence;
[0020] Step 5: Lay a layer of hard soil and bury the water inlet pipe, grout inlet pipe, and material inlet pipe;
[0021] Step 6: Install the slab mold according to the dimensions of the expansion system, tie the slab reinforcement, pour the slab and make the left side of the slab be concave and convex. After the slab has cured to the predetermined strength, the groove on the lower right side of the slab must be tightly connected to the expansion system. Feed pipe holes must be left at the designated positions on the slab. Feed pipes are placed in each hole and extended to the asphalt cover layer.
[0022] Step 7: After the slab is laid out, lay the crushed stone layer by layer on the left side of the slab and fill in the water inlet pipe, grout inlet pipe and feed pipe.
[0023] Step 8: Lay the asphalt cover layer and seal the inlet of the feed pipe.
[0024] The present invention has the following beneficial effects:
[0025] (1) After the entire road and bridge transition structure is completed, when a vehicle travels to this section of the road, the steel piles and steel pile caps arranged inside the foundation can prevent the roadbed from experiencing differential settlement through the soil arch effect; the expansion system arranged on the left side of the abutment can offset the horizontal force generated by the vehicle; the buffer material arranged on the right end of the approach slab and the left end of the abutment can prevent the two from being damaged by impact.
[0026] (2) When a large settlement occurs at a certain location of the roadbed, the earth pressure signal of the earth pressure gauge located at that location will inevitably show a gradual increase. According to the earth pressure signal received by the signal receiver, manually open the grout inlet pipe cover and pour in lime slurry. After filling, close the cover. When the earth pressure increases to the preset value, the corresponding earth pressure signal will be transmitted to the signal control ball valve. The ball valve opens to release the lime slurry inside the feed pipe, thereby consolidating the foundation at that location so that it will no longer settle.
[0027] (3) Grouting can only control the amount of settlement, but it cannot treat the differential settlement that has already occurred. Therefore, the asphalt cover layer at the corresponding location can be broken open and the top inlet of the feed pipe can be opened to inject expansive cement into it. At the same time, the cover plate of the water inlet pipe can be opened and water can be injected into the water inlet pipe. The water inside the water inlet pipe can be sprayed out in a mist form and fully mixed with the expansive cement in the small space at the corresponding location of the lower part of the lifting system. Since the four walls of the small space are fixed, the expansive cement can only develop upwards during the curing process, thereby reducing the differential settlement of the subgrade by lifting the movable plate. After the treatment is completed, the asphalt cover layer on the top of the broken subgrade should be leveled. If settlement occurs in other areas of the subgrade, the same steps can be taken.
[0028] (4) This invention employs multiple treatment measures to provide comprehensive and multi-layered protection for the foundation subgrade, approach slabs, and abutments, preventing significant differential settlement. If settlement occurs at any point in the subgrade due to rainfall or other factors, the settlement area can be consolidated and lifted using a grouting system and a jacking system. This bridge transition structure effectively solves the problem of bridge approach slab settlement and offers a simple and efficient construction method. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of a road-bridge transition structure for controlling bridge approach slab settlement according to the present invention.
[0030] Figure 2 This is a schematic diagram of the telescopic system structure.
[0031] Figure 3 Schematic diagram of the slab structure.
[0032] Figure 4 This is a schematic diagram of the grout inlet pipe, signal control ball valve, and earth pressure gauge.
[0033] Figure 5 Schematic diagram of the lower trough structure of the roadbed lifting system.
[0034] Figure 6 A schematic diagram of the overturned cover structure of the roadbed lifting system.
[0035] Figure 7 Schematic diagram of the roadbed lifting system and the interface structure of the lower water inlet pipe.
[0036] Figure 8 Schematic diagram of the roadbed lifting system after pile driving.
[0037] Figure 9 Schematic diagram of the roadbed lifting system structure after the feed pipe is installed.
[0038] The components include: 1. Abutment body; 2. Pier; 3. Support; 4. Beam; 5. Asphalt overburden; 6. Approach slab; 7. Expansion joint system; 8. Crushed stone layer; 9. Hard soil layer; 10. Steel pile; 11. Steel pile cap; 12. Subgrade lifting system; 13. Signal control ball valve; 14. Earth pressure gauge; 15. Water inlet pipe; 16. Grout inlet pipe; 17. Expansion joint; 18. Signal receiver; 19. Signal line; 20. Lower trench; 21. Top cover plate; 22. Pile hole; 23. Feed pipe interface; 24. Feed pipe; 25. Pipe end cover plate; 26. Buffer spring; 27. Pier beam; 28. Buffer pad; 29. Ball valve protection box; 30. Buffer material; 31. Subgrade; 32. Water inlet pipe interface; 33. 34. Feed inlet; 35. Baffle; 36. Pile slot; 37. Positioning hole; 38. Positioning sheath; 39. Movable cover plate; 30. Water outlet. Implementation
[0039] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.
[0040] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.
[0041] like Figure 1 As shown, a road-bridge transition structure for controlling bridge approach slab settlement is used to connect the roadbed and the abutment. With the abutment body 1 as the boundary, the left side is the roadbed side and the right side is the abutment side, or the left side is the abutment side and the right side is the roadbed, with a completely symmetrical arrangement. A convex-shaped bearing platform 2 is installed on top of the abutment body 1. The right side of the bearing platform 2 supports the beam 4 via supports 3, which are evenly distributed laterally. The beam 4 is the main structure of the bridge. An expansion joint 17 is provided between the bearing platform 2 and the beam 4 to limit the movement of the beam 4.
[0042] The left side of the foundation 2 supports the mounting plate 6. A groove is provided at the bottom of the mounting plate 6, and an expansion joint 7 is installed within the groove. For example... Figure 2 and 3 As shown, several support beams 27 are vertically fixed in the groove at the bottom of the approach slab 6. The support beams 27 divide the groove into several intervals, and a buffer spring 26 is placed in each interval. The top of the buffer spring is equipped with a buffer pad 28, which is tightly connected to the inner wall of the groove and keeps the spring under tension. This arrangement can offset the horizontal load generated when the vehicle is moving. The right end face of the approach slab 6 and the corresponding left end face of the support 2 are both covered with buffer material 30, and the gap between them is filled with concrete. This arrangement can protect the approach slab and the support 2 from damage.
[0043] The roadbed structure, from bottom to top, consists of a foundation roadbed 31, a hard soil layer 9, a crushed stone layer 8, and an asphalt cover layer 5. Twelve steel piles 10 are embedded within the foundation roadbed 31 in a 3×4 array, each pile 10 equipped with a steel pile cap 11. A grouting pipe 16 sequentially passes through the asphalt cover layer 5, the crushed stone layer 8, and the hard soil layer 9 from the ground surface into the foundation roadbed 31, and is embedded at the top and bottom of the steel piles 10.
[0044] like Figure 4 As shown, the grout inlet pipe 16 is equipped with a signal-controlled ball valve 13, which is connected to an earth pressure gauge 14. The ball valve is opened and closed by the signal output from the earth pressure gauge. After the ball valve opens automatically, it releases the lime slurry inside the grout inlet pipe to consolidate the soil in that area. This arrangement allows for grouting and consolidation of the soil in any area of the roadbed according to the magnitude of the earth pressure at each location.
[0045] Earth pressure gauge 14 is embedded at the center of an array of 12 steel piles 10 in the foundation subgrade 31. Earth pressure gauge 14 is connected to signal control ball valve 13 and signal receiver 18 located on the asphalt cover layer 5 via signal line 19. This arrangement allows for the determination of earth pressure distribution patterns via the signal receiver and enables timely grouting based on earth pressure changes at each location. The signal control ball valve 13 is externally protected by a ball valve protection box 29. The ball valve protection box 29 is made of perforated thin steel plate with 0.5mm diameter holes. A reverse osmosis membrane is adhered to the perforated steel plate. This membrane allows liquid to flow out but prevents soil particles from entering, thus ensuring smooth discharge of lime slurry while preventing soil particles from entering the box, thereby protecting the signal control ball valve 13.
[0046] The subgrade 31 is equipped with a subgrade lifting system 12, which includes a lower trough 20 and an upper cover plate 21 that are connected by an insertion. The feed pipe 24 passes through the upper cover plate 21 from the top and pours expansive cement into the lower trough 20. The water inlet pipe 15 passes through the lower trough 20 from the bottom and sprays water mist to combine with the expansive cement to form a solid, which lifts the upper cover plate 21, thereby compensating for the settlement of the subgrade. The lower trough 20 is equipped with a pile insertion slot 35, which is inserted and fixed to the steel pile 10.
[0047] like Figure 5 As shown, the lower trench 20 includes a baffle 34, a pile insertion slot 35, and a positioning hole 36. The pile insertion slot 35 is fixedly connected to the baffle 34 and is used to insert and cooperate with the steel pile 10. The baffle 34 divides the lower trench 20 into several small spaces. Figure 6 As shown, the upper cover plate 21 includes a movable cover plate 38, a stake hole, and a positioning sheath 37. (As indicated...) Figure 7 , 8 As shown in Figure 9, the positioning sheath 37 is inserted into the positioning hole 36 to cover the upper cover plate 21 on the lower trough 20, and the insertion hole 22 overlaps with the insertion groove 35; the movable cover plate 38 is hinged to the upper cover plate 21 or rotated through the central shaft, and its number is consistent with the number of small spaces inside the lower trough 20, and it can completely cover the corresponding small space. When subjected to external force, the movable cover plate 38 can be opened; the upper part of the movable cover plate 38 is provided with a feed pipe interface 23, and the feed pipe interface 23 is positioned in accordance with the water inlet interface 32 of the lower trough.
[0048] The water inlet pipe 15 is laid from the ground into the foundation roadbed 31 and is connected to each small space of the lower trough 20 of the lifting system through the water inlet pipe interface 32 at the bottom of the lower trough 20. The water inlet pipe 15 is made of stainless steel.
[0049] The basic roadbed 31 is covered with a hard soil layer 9, a crushed stone layer 8 is laid on top of the hard soil layer 9, and an asphalt cover layer 5 is laid on top of the crushed stone layer 8. The crushed stone layer 8 is connected to the approach slab 6 by a sloping joint. The contact surface of the approach slab 6 has a serrated protrusion structure to increase the friction with the crushed stone layer 8.
[0050] A construction method for a road-bridge transition structure for controlling bridge approach slab settlement includes the following steps:
[0051] Step 1: Install the bridge abutment body 1 and the pier cap 2, and install the support 3 and beam 4 on the right side of the pier cap. Construct the expansion system 7 on the left side of the pier cap 2. When constructing the expansion system, the pier cap beam 27 can be poured first. After the pier cap beam reaches the design strength, the buffer spring 26 and buffer pad 28 can be installed in sequence.
[0052] Step 2, when constructing the foundation roadbed 31, first lay a portion of shallow roadbed, and then embed grout inlet pipe 16, water inlet pipe 15, signal control ball valve 13 and earth pressure gauge 14 in the roadbed. The signal control ball valve 13 is connected to the earth pressure gauge 14, and the opening and closing of the ball valve is controlled by the signal output from the earth pressure gauge.
[0053] Step 3: Install the roadbed lifting system 12. First, place the constructed lower trough 20 on the paved roadbed and connect the water inlet pipe 15. Then, install the water outlet 39 in sequence. After the water outlet 39 is installed, cover the upper part of the lifting system cover plate 21 on the lower trough 20 and insert the positioning sheath 37 into the positioning hole 36. Then, place the movable plates 38 on the top of the upper cover plate 21 of the lifting system in sequence. After installation, make sure that the pile hole 22 and the pile slot 35 are aligned. Then, insert the steel pile 10 into the pile hole 22 and install the steel pile cap 11. Finally, connect the feed pipe 24 to the feed pipe interface 23 on the top of each movable plate 38.
[0054] The end of the water inlet pipe 15 is equipped with a water outlet hole 39. The diameter of the water outlet hole is extremely small, which can ensure that the water inside the water inlet pipe 15 is sprayed into several small spaces of the lower tank 20 in the form of a mist.
[0055] Step 4: Continue laying the roadbed and sequentially embed the grout inlet pipe 16, signal control ball valve 13, ball valve protection box 29, feed pipe 24 and earth pressure gauge 14;
[0056] Step 5: Lay a hard soil layer 9 and bury the water inlet pipe 15, grout inlet pipe 16, and material inlet pipe 24;
[0057] Step 6: Install the formwork 6 according to the dimensions of the expansion system 7, tie the reinforcement bars of the expansion system 7, pour the concrete for the expansion system 7, and make the left side of the expansion system 6 beveled. After the expansion system 6 has cured to the predetermined strength, the groove on the lower right side of the expansion system 7 should be tightly connected to the expansion system 7 so that the buffer spring 26 is under stress. Feed pipe holes should be left at the designated locations on the expansion system 6. Feed pipes 24 should be placed in each hole and extended to the asphalt cover layer 5. After the expansion system 6 is constructed, buffer material 30 should be pasted on the right side of the expansion system 6 and the left side of the foundation, and concrete should be poured in the remaining gaps.
[0058] Step 7: After the slab is laid out, lay the crushed stone layer 8 layer by layer on the left side of the slab and fill in the water inlet pipe 15, grout inlet pipe 16 and feed pipe 24.
[0059] Step 8: Lay the asphalt cover layer 5 and seal the inlet 33 of the feed pipe.
[0060] The ends of the water inlet pipe 15 and the slurry inlet pipe 16 are both located on the upper part of the asphalt cover layer 5, and pipe opening covers 25 need to be installed at the pipe openings. The covers are in a closed state and can be opened at any time during use. The construction is now complete.
[0061] When a significant settlement occurs at a certain location in the roadbed, the earth pressure signal of the earth pressure gauge 14 located at that location will inevitably show a gradual increase. Based on the earth pressure signal received by the signal receiver 18, the grout inlet pipe cover 25 is manually opened and lime slurry is poured in. After filling, the cover is closed. When the earth pressure increases to the preset value, the corresponding earth pressure signal will be transmitted to the signal control ball valve 13. The ball valve opens to release the lime slurry inside the inlet pipe, thereby consolidating the foundation at that location and preventing further settlement.
[0062] Grouting can only control the amount of settlement, but cannot address the existing differential settlement. Therefore, the asphalt cover layer 5 at the corresponding location can be broken open and the top inlet of the feed pipe 24 can be opened to inject expansive cement into it. At the same time, the water inlet pipe cover plate 25 can be opened and water can be injected into the water inlet pipe, so that the water inside the water inlet pipe is sprayed out in a mist form and fully mixed with the expansive cement in the small space at the corresponding location of the lower tank 20 of the lifting system. Since the four walls of the small space are fixed, the expansive cement can only develop upwards during the curing process. The differential settlement of the roadbed can be reduced by lifting the movable plate.
[0063] After the roadbed is raised, the asphalt cover layer 5 that has been broken on the top of the roadbed is leveled. If settlement occurs in other parts of the roadbed, the same steps can be taken.
[0064] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.
Claims
1. A road-bridge transition structure for controlling bridge approach slab settlement, used to connect the roadbed and the abutment, with the abutment body (1) as the boundary, the left side being the roadbed side and the right side being the abutment side; a bearing platform (2) is arranged on the top of the abutment body (1), the bearing platform (2) is convex in shape, the right side of the bearing platform (2) supports the beam body (4) through the support (3), and the left side of the bearing platform (2) supports the approach slab (6), characterized in that: The bottom of the mounting plate (6) is provided with a groove, and a telescopic system (7) is installed in the groove. The roadbed consists of a base roadbed (31), a hard soil layer (9), a crushed stone layer (8), and an asphalt cover layer (5) from bottom to top. Several steel piles (10) are buried inside the base roadbed (31). Several grouting pipes (16) pass through the asphalt cover layer (5), the crushed stone layer (8), and the hard soil layer (9) from the ground to enter the base roadbed (31) and are buried at the top and bottom of the steel piles (10). The grouting pipes (16) are equipped with signal control ball valves (13). The signal control ball valves (13) are connected to the earth pressure gauge (14). The ball valves are opened and closed by the signal output of the earth pressure gauge. After the ball valves open automatically, the lime slurry inside the grouting pipes is released to consolidate the soil. The basic roadbed (31) is equipped with a roadbed lifting system (12), including a lower trough (20) and an upper cover plate (21) that are connected by an insertion. The feed pipe (24) passes through the upper cover plate (21) from the top and pours expansive cement into the lower trough (20). The water inlet pipe (15) passes through the lower trough (20) from the bottom and sprays water mist to combine with the expansive cement to form a solid, which lifts the upper cover plate (21) to compensate for the settlement of the roadbed. The lower trough (20) is equipped with a pile insertion slot (35) to be inserted and fixed with steel piles (10). The basic roadbed (31) is covered with a hard soil layer (9), and a crushed stone layer (8) is laid on top of the hard soil layer (9). The crushed stone layer (8) and the approach slab (6) are connected by a slope oblique connection. An asphalt cover layer (5) is laid on top of the crushed stone layer (8).
2. The road-bridge transition structure for controlling bridge approach slab settlement according to claim 1, characterized in that: Several support beams (27) are vertically fixed in the groove at the bottom of the mounting plate (6). The support beams (27) divide the groove into several intervals. A buffer spring (26) is placed in each interval. A buffer pad (28) is provided at the top of the buffer spring and is tightly connected to the inner wall of the groove, so that the spring is under stress.
3. The road-bridge transition structure for controlling bridge approach slab settlement according to claim 1, characterized in that: The right end face of the slab (6) and the left end face of the foundation (2) are both covered with cushioning material (30), and concrete is poured in the gap between them.
4. The road-bridge transition structure for controlling bridge approach slab settlement according to claim 1, characterized in that: The earth pressure gauge (14) is buried at the center of several steel piles (10) of the foundation roadbed (31). The earth pressure gauge (14) is connected to the signal control ball valve (13) and the signal receiver (18) located on the asphalt cover layer (5) through the signal line (19). The outside of the signal control ball valve (13) is provided with a ball valve protection box (29). The ball valve protection box (29) is made of perforated thin steel plate with a hole diameter of 0.5 mm. The perforated thin steel plate is pasted with a reverse osmosis membrane. The reverse osmosis membrane only allows liquid to flow out and does not allow soil particles to enter. This ensures that lime milk can be discharged smoothly and prevents soil particles from entering the box, thus protecting the signal control ball valve (13).
5. The road-bridge transition structure for controlling bridge approach slab settlement according to claim 1, characterized in that: The roadbed lifting system (12) includes a lower trough (20) and an upper cover plate (21); the lower trough (20) includes a baffle (34), a pile insertion slot (35), and a positioning hole (36), the pile insertion slot (35) is fixedly connected to the baffle (34), and the pile insertion slot (35) is used to insert and cooperate with the steel pile (10); the baffle (34) divides the lower trough (20) into several small spaces; the upper cover plate (21) includes a movable cover plate (38), a pile insertion hole, and a positioning sheath (37), the positioning sheath (37) is inserted and cooperated with the positioning hole (36) to... The upper cover plate (21) covers the lower tank (20) and overlaps the insertion hole (22) with the insertion slot (35); the movable cover plate (38) is hinged to the upper cover plate (21) or rotated through the central shaft, and its number is consistent with the number of small spaces inside the lower tank (20), and can completely cover the corresponding small space. When subjected to external force, the movable cover plate (38) can be opened; the upper part of the movable cover plate (38) is provided with a feed pipe interface (23), and the feed pipe interface (23) is in a position corresponding to the water inlet pipe interface (32) of the lower tank.
6. The road-bridge transition structure for controlling bridge approach slab settlement according to claim 1, characterized in that: The water inlet pipe (15) is laid from the ground into the foundation roadbed (31) and connected to each small space of the lower trough (20) of the lifting system through the water inlet pipe interface (32) at the bottom of the lower trough (20). The water inlet pipe (15) is made of stainless steel.
7. A construction method for a road-bridge transition structure for controlling bridge approach slab settlement according to any one of claims 1-6, characterized in that, Specifically, the following steps are included: Step 1: Install the bridge abutment body (1) and the pier cap (2), and install the support (3) and beam body (4) on the right side of the pier cap. Construct the expansion joint system (7) on the left side of the pier cap (2). Step 2, when constructing the foundation roadbed (31), a grout inlet pipe (16), a water inlet pipe (15), a signal control ball valve (13) and an earth pressure gauge (14) are buried in the roadbed respectively. The signal control ball valve (13) is connected to the earth pressure gauge (14), and the opening and closing of the ball valve is controlled by the signal output of the earth pressure gauge. Step 3: Install the roadbed lifting system (12). First, place the completed lower trench (20) on the paved roadbed and connect the water inlet pipe (15). Insert the pile slot (35) and the steel pile (10) into the fixed position. Connect the feed pipe (24) to the lower trench (20). After installation, cover the lower trench (20) with the upper cover plate (21). Step 4: Continue laying the roadbed and install the grout inlet pipe (16), signal control ball valve (13) and earth pressure gauge (14) in sequence. Step 5: Lay a hard soil layer (9) and bury the water inlet pipe (15), grout inlet pipe (16), and feed pipe (24); Step 6: Install the formwork (6) according to the dimensions of the expansion system (7), tie the reinforcement bars of the expansion system (7), pour the expansion system and make the left side of the expansion system convex and concave. After the expansion system is cured to the predetermined strength, the groove on the lower right side of the expansion system (7) should be tightly connected. The feed pipe arrangement hole should be left at the designated position of the expansion system (7), and the feed pipe (24) should be arranged in each hole and extended to the asphalt cover layer (5). Step 7: After the slab is laid out, lay the crushed stone layer (8) layer by layer on the left side of the slab and fill in the water inlet pipe (15), grout inlet pipe (16) and feed pipe (24). Step 8: Lay the asphalt cover layer (5) and seal the inlet (33) of the feed pipe.