Structure and Construction Method of Prefabricated Prestressed Ramping Slab for Preventing Void under Bridge Head with High Fill

Abstract

The present invention discloses a structure and construction method of a prefabricated prestressed slab for preventing voiding at the bridgehead of high fill, which is applicable to the judgment and treatment of voiding of the bridgehead slab of high fill subgrade. This structure includes a prefabricated prestressed slab, monitoring devices and grouting one-way valve devices arranged at different positions of the slab. The position and area of slab voiding can be accurately judged through the numerical values of the strain gauges and pressure sensors of the monitoring devices. The structures and construction methods of the prefabricated slab, monitoring devices and grouting one-way valves are also disclosed. The present invention can quickly judge the position and area of voiding, and can timely and repeatedly carry out grouting treatment on the voiding part of the slab according to the size of the voiding area, effectively avoiding the problem that the slab breaks due to large-area voiding under the slab, thus causing vehicle bumping at the bridgehead.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge structures and construction, and particularly relates to a high-fill bridgehead anti-separation precast prestressed slab structure and a construction method thereof. Background Art

[0002] Vehicle bumping at the bridgehead of high-fill roadbeds has always been a difficult problem in highway construction. Due to the large self-weight of high-fill roadbeds and relatively large natural settlement, the fill under the bridgehead slab is extremely likely to settle and separate, resulting in slab fracture and vehicle bumping at the bridgehead. Since the separation is greater longitudinally near the bridge side than the subgrade side under the slab and greater in the middle of the road than the roadside transversely, the formed separation boundary line is difficult to accurately calculate theoretically. For the traditional ground penetrating radar technology for detecting slab separation, since the slab is a concealed project, there are certain limitations and one-sidedness, and it cannot accurately judge the position and area of the separation, let alone the height of the separation. The anti-separation precast prestressed slab structure of the present invention can accurately judge the position, area and height of the separation according to the magnitude of the monitored values, and use it as the basis for whether to carry out grouting treatment.

[0003] The present invention adopts the design of high-grade prestressed concrete slabs, which are thinner than ordinary reinforced concrete slabs, saving the consumption of steel bars and concrete; the prestressed slabs work seamlessly, increasing the durability of the slabs; the stiffness of the slabs is increased, reducing the impact effect and slab deformation caused by passing vehicle loads, and reducing the pressure on the underlying layer at the bottom of the slab, thereby slowing down the settlement speed of the fill behind the abutment.

[0004] During the settlement period of the subgrade, post-construction settlement continues to occur, and a single grouting is difficult to completely eliminate the problem of slab separation. The present invention is provided with multiple grouting holes, and the separation continuously generated during the settlement period can be grouted in multiple times. The traditional treatment method requires drilling and grouting on the slab. Firstly, it affects traffic during the construction period. Secondly, drilling needs to damage the asphalt concrete surface layer on the slab, and after damage, the asphalt surface layer needs to be milled and re-paved. Thirdly, the construction period is long, the cost is high, and there are potential safety hazards. The grouting steel pipes of the present invention are led from the reserved grouting holes to both sides of the bridgehead subgrade, and grouting construction is carried out on both sides of the bridgehead subgrade during grouting, without damaging the asphalt surface layer and without affecting vehicle traffic. After grouting, the pipeline is filled with slurry, and the pipeline cannot be reused after solidification. Therefore, multiple grouting check valve devices are provided to ensure that multiple groutings can be carried out. The pressure during grouting is from bottom to top, and the setting of the wedge-shaped cork can prevent the slurry from entering the unused grouting steel pipes, thus ensuring that multiple groutings can be carried out, solving the problem of slab separation during the settlement period of the subgrade and preventing the occurrence of vehicle bumping at the bridgehead. Summary of the Invention

[0005] The technical problems to be solved by the present invention are: the small stiffness and large vibration of ordinary reinforced concrete slabs for high-fill bridgehead roadbeds, and the problems that the accurate position and area of separation cannot be judged, and multiple groutings cannot be carried out.

[0006] To solve the above technical problems, the present invention provides a structure of a precast prestressed slab for preventing voiding at the bridgehead of high embankment, which is used for judging and treating the voiding of the bridgehead slab of high embankment subgrade. The structure is characterized in that it includes the following three parts:

[0007] A precast prestressed slab, which is set to be bolted to the bracket;

[0008] One or more groups of monitoring devices, which are arranged near the voiding boundary lines of the slab at different times and are composed of a reinforcing bar stress gauge arranged on the upper part and a pressure sensor arranged on the lower part;

[0009] A grouting check valve device, which includes a grouting steel pipe, a reserved grouting hole in the slab, a wedge-shaped cork and a sealing rubber pad, and the sealing rubber pad is arranged at the bottom of the slab.

[0010] According to another specific embodiment of the present invention, the precast prestressed slab further includes:

[0011] A group of precast slab groups A (2), precast slab groups B (3) and prestressed wet joints (4) arranged along the length direction of the subgrade. Both the precast slab groups A (2) and precast slab groups B (3) are composed of a plurality of horizontally arranged concrete blocks. Adjacent horizontally arranged concrete blocks are connected by tie rods (5). One end of the precast slab group A (2) is fixed to the bracket (1) of the bridge abutment through anchor bolts, and the other end of the precast slab group A (2) is connected to the precast slab group B (3) through a prestressed wet joint (4).

[0012] According to still another specific embodiment of the present invention, the prestressed wet joint (4) further includes:

[0013] Embedded ribbed steel strands (20) in the precast slab group A (2), steel strands (8), connectors (9), plastic pipes (10), sealing sleeves (11), corrugated pipes (12), and wet joint concrete (21) in the precast slab group B (3).

[0014] According to yet another specific embodiment of the present invention, the monitoring device further includes:

[0015] It is composed of a plurality of strain gauges (13) tied to the bottom longitudinal structural steel bars and pressure sensors (14) embedded at positions vertically corresponding to the strain gauges (13) at the bottom of the slab.

[0016] According to still another specific embodiment of the present invention, the grouting check valve device further includes: a reserved grouting hole in the slab (15), a wedge-shaped cork (17), and a sealing rubber pad.

[0017] According to another specific embodiment of the present invention, the thickness of the precast slab group A (2) is 25 cm to 40 cm, the width is adjusted according to the lane width, the length is 7 m to 8 m, and the concrete grade is 40 Mpa to 50 Mpa; the diameter of the steel strand is 15.20 mm, and the strength is 1860 Mpa; the anchor is of the BJM15-3 series.

[0018] According to still another specific embodiment of the present invention, the steel strand reinforcement of the precast slab group A (2) is designed according to the possible existence of a certain length of void, and the target value of the void length is 4 m to 5 m.

[0019] According to yet another specific embodiment of the present invention, the thickness of the precast slab group B (3) is 25 cm to 40 cm, the width is adjusted according to the lane width, the length is determined according to the height of the backfill behind the abutment, and the concrete grade is 40 Mpa to 50 Mpa; the diameter of the steel strand is 15.20 mm, and the strength is 1860 Mpa; the anchor is of the BJM15-2 series.

[0020] According to another aspect of the present invention, a construction method for a high-fill bridgehead anti-void precast prestressed slab structure is further provided, including the following steps:

[0021] 1) Prefabrication: Prefabricate the precast slab group A (2) and the precast slab group B (3). The precast slab group A (2) reserves the corrugated steel strand (20), and the strain gauge (13) is embedded on the longitudinal structural reinforcement (16) at the bottom of the precast slab group A (2), and a pressure sensor installation groove is reserved at the corresponding position at the bottom of the slab. The precast slab group A (2) reserves the grouting reserved holes (15) for the slab.

[0022] 2) Tensioning and grouting: After the concrete strength of the precast slab group A (2) reaches 100%, the steel strand (23) is tensioned and grouted.

[0023] 3) Chiseling: Chisel the wet joint (4) side of the precast slab group A (2) and the precast slab group B (3).

[0024] 4) Pressure sensor installation: Remove the template of the reserved installation groove of the precast slab group A (2), install the pressure sensor (14) in the installation groove, and after adjusting the bottom bearing surface of the pressure sensor (14) to be flush with the bottom of the precast slab group A (2), fix the pressure sensor with structural adhesive.

[0025] 5) Check valve installation: Clean the reserved grouting reserved holes (15) on the precast slab, plug the wedge-shaped cork (17) into the grouting reserved holes (15) for the slab from the bottom, and finally stick and seal the wedge-shaped cork (17) with a sealing rubber pad (18) at the bottom of the slab.

[0026] 6) Construction of the pressure sensor cushion layer: At the position of the pressure sensor (14) corresponding to the cushion layer of the approach slab, a square groove with a size of 50 cm × 50 cm × 2 cm is pre-chiseled on the subbase layer (6), fine sand is paved and compacted, and the top surface of the fine sand is flush with the surrounding cushion layer;

[0027] 7) Installation of precast slabs: Two layers of tarpaulins are laid on the corbels (1) of the abutment, the precast slab group A (2) is installed by a crane, and one end of the precast slab group A (2) is fixed to the corbel (1) by anchor bolts, and then the precast slab group B (3) is hoisted to the predetermined position for installation;

[0028] 8) Connection of steel strands: The embedded crimped steel strands (20) of the precast slab group A (2) are connected to the steel strands (8) of the precast slab group B (3) by a connector (9). A plastic pipe (10) is sleeved outside the connector (9). The end of the plastic pipe (10) close to the precast slab group A (2) is sealed, and the end close to the precast slab group B (3) is hermetically connected to the bellows (12) of the precast slab group B (3), and both ends of the plastic pipe (10) leave spaces required for the tensioning and movement of the steel strand connector (9);

[0029] 9) Construction of wet joints: The longitudinal prestressed wet joint (4) and the ordinary concrete joint (24) connected by tie rods (5) are poured at one time from one side of the bridge, and cured by sprinkling water and covering for 7 days;

[0030] 10) Tensioning of the precast slab group B (3): When the strength of the prestressed wet joint (4) reaches 100%, the steel strands of the precast slab group B (3) are tensioned, and after tensioning, grouting and sealing the anchor are carried out;

[0031] 11) Treatment of expansion joints: Polyurethane asphalt is filled in the expansion joint between the front wall (22) and the precast slab group A (2);

[0032] 12) Installation of grouting pipes: A grouting steel pipe (19) is connected to the approach slab grouting reserved hole (15) reserved on the precast slab group A (2) and led to the outside of the approach slab at the bridge head.

[0033] The beneficial effects of the present invention are as follows:

[0034] 1) The monitoring device provided by the present invention can accurately detect and judge the position, area and height of the void, so as to accurately calculate the void volume, timely carry out grouting treatment, prevent the approach slab from cracking, and prevent bump at bridge head;

[0035] 2) The present invention adopts a prestressed concrete approach slab, which is thinner than the ordinary reinforced concrete approach slab, saving the consumption of steel bars and concrete; the prestressed slab works seamlessly, increasing the durability of the approach slab; the stiffness of the slab is increased, reducing the impact effect and the resulting deformation of the approach slab when the vehicle load passes, reducing the pressure of the slab bottom on the subbase layer, thereby slowing down the settlement speed of the backfill behind the abutment.

[0036] 3) The present invention provides multiple reserved holes for slab grouting. The setting of the one-way valve ensures that grouting through a certain reserved hole for slab grouting does not affect the subsequent use of other reserved holes for slab grouting, and grouting can be carried out in multiple times according to different occurrence times of voids, solving the problem of multiple groutings for slab voids. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic cross-sectional structure diagram of the present invention;

[0038] Figure 2 is a schematic plan structure diagram of the present invention;

[0039] Figure 3 is an enlarged schematic diagram of the prestressed wet joint of the present invention;

[0040] Figure 4 is a schematic cross-sectional view of the precast slab groups A and B near the wet joint end of the present invention;

[0041] Figure 5 is a schematic structure diagram of the reserved grouting hole of the present invention;

[0042] Figure 6 is a schematic longitudinal sectional view along the road at the bridgehead;

[0043] Figure 7 is a schematic transverse sectional view along the road at the bridgehead;

[0044] Figure 8 is a schematic diagram of the void demarcation line at the bridgehead.

[0045] In the figures: 1, bracket; 2, precast slab group A; 3, precast slab group B; 4, prestressed wet joint; 5, tie rod; 6, subbase; 7, pavement structure; 8, steel strand of B slab; 9, connector; 10, plastic pipe; 11, sealing sleeve; 12, corrugated pipe; 13, strain gauge; 14, pressure sensor; 15, reserved hole for slab grouting; 16, longitudinal structural steel bar; 17, wedge-shaped cork; 18, sealing rubber pad; 19, grouting steel pipe; 20, embedded ribbed steel strand; 21, wet joint concrete; 22, front wall; 23, steel strand of A slab; 24, ordinary concrete joint. EMBODIMENTS

[0046] First of all, it is necessary to explain the law of subgrade void under the slab:

[0047] 1. As Figure 6 shown, a schematic longitudinal sectional view along the road at the bridgehead is given. It can be seen that the void depth on the bridgehead side is greater than that on the subgrade side along the longitudinal direction of the road.

[0048] 2. As Figure 7As shown, a schematic diagram of the cross-section along the transverse direction of the road at the bridgehead is given. It can be seen that the depth of the void in the middle of the road along the transverse direction of the roadbed is greater than that at the road shoulder.

[0049] 3. As Figure 8 shown, a schematic diagram of the void demarcation line at the bridgehead is given. It can be seen that with different periods of highway operation, there are different void demarcation lines between the approach slab and the roadbed. The position and shape of the void line are related to the structural design of the approach slab, vehicle load, roadbed foundation, treatment method of the backfill behind the abutment, etc.

[0050] Therefore, in view of the relevant laws in the above actual construction process and the defects in the prior art described in the present invention, the present invention provides a structure of a precast prestressed approach slab for preventing voids at high-fill bridgeheads as Figure 1-2 shown, which is used for the judgment and treatment of voids in the approach slab of the high-fill roadbed. The structure is characterized in that it includes the following three parts:

[0051] The precast prestressed approach slab, which is set to be bolted to the corbel;

[0052] One or more groups of monitoring devices, which are arranged at different positions of the approach slab and are composed of a reinforcing bar stress gauge arranged on the upper part and a pressure sensor arranged on the lower part;

[0053] The grouting one-way valve device, which includes a grouting steel pipe, a reserved hole for grouting the approach slab, a wedge-shaped cork and a sealing rubber pad, and the sealing rubber pad is arranged at the bottom of the approach slab.

[0054] Among them, preferably, the detection device is arranged near or close to the void demarcation line of the approach slab at different times.

[0055] It should be noted that the precast and prestressed technologies have been widely applied in bridges, but the prestressed technology has not been applied to the approach slab yet. The prestressed approach slab has the following advantages:

[0056] 1. The thickness of the prestressed approach slab is smaller than that of the ordinary reinforced concrete approach slab, and the amount of steel bars and concrete used in the slab is less than that of the ordinary reinforced concrete.

[0057] 2. After the approach slab adopts prestress, the rigidity of the approach slab becomes larger and the deformation becomes smaller, reducing the amplitude of the slab during driving and delaying the time of void formation under the approach slab.

[0058] 3. The prestressed approach slab works seamlessly, extending the service life of the slab.

[0059] In addition, preferably, the layout of the sensors on the approach slab has the following rules:

[0060] 1. There are a certain number of monitoring points on the approach slab, and a reinforcing bar strain gauge and a pressure sensor are respectively arranged above and below each monitoring point.

[0061] 2. The monitoring points are arranged near the void separation boundaries of the approach slab at equal intervals in the horizontal plane of the approach slab at different times.

[0062] 3. By substituting the values of the steel strain gauges and pressure sensors at each monitoring point under no-load and load conditions into the stress equation of the approach slab void, the void area and void height can be solved. The traditional radar monitoring technology for voids has certain limitations and one-sidedness because the approach slab is a concealed project. It cannot accurately judge the location and area of the void, nor can it judge the void height of the approach slab, and thus cannot calculate the volume of grout required during grouting.

[0063] As Figure 1-2 shown, the monitoring device consists of several strain gauges (13) tied to the bottom longitudinal structural steel bars and pressure sensors (14) embedded at the positions corresponding to the strain gauges (13) vertically at the bottom of the approach slab.

[0064] As Figure 2 shown, the structure of the precast prestressed approach slab includes precast slab groups A (2), precast slab groups B (3), and prestressed wet joints (4) arranged along the length direction of the subgrade. Both precast slab groups A (2) and precast slab groups B (3) are composed of multiple concrete slabs arranged horizontally. Adjacent horizontal concrete slabs are connected by tie rods (5). One end of the precast slab group A (2) is fixed to the corbel (1) of the abutment by anchor bolts, and the other end of the precast slab group A (2) is connected to the precast slab group B (3) through the prestressed wet joint (4).

[0065] As Figure 2-3 shown, the thickness of the precast slab group A (2) is 25 cm to 40 cm, the width is adjusted according to the lane width, the length is 7 m to 8 m, and the concrete grade is 40 Mpa to 50 Mpa; the diameter of the steel strand is 15.20 mm, and the strength is 1860 Mpa; the anchor is of the BJM15-3 series. The steel strand reinforcement of the precast slab group A (2) is designed according to the possible existence of a certain length of void, and the target value of the void length is 4 m to 5 m.

[0066] As Figure 2-3 shown, the thickness of the precast slab group B (3) is 25 cm to 40 cm, the width is adjusted according to the lane width, the length is determined according to the height of the backfill behind the abutment, and the concrete grade is 40 Mpa to 50 Mpa; the diameter of the steel strand is 15.20 mm, and the strength is 1860 Mpa; the anchor is of the BJM15-2 series.

[0067] As Figure 4 shown, the prestressed wet joint (4) includes: the embedded ribbed steel strand (20) in the precast slab group A (2), the steel strand (8), connector (9), plastic pipe (10), sealing sleeve (11), corrugated pipe (12), and wet joint concrete (21) in the precast slab group B (3).

[0068] As Figure 5 shown, the grouting one-way valve device is composed of a slab grouting reserved hole (15), a wedge-shaped cork (17), and a sealing rubber pad (18).

[0069] Among them, it should be noted that when the slab is voided to a certain area and the load stress on the slab is greater than the design stress, the slab will be damaged. Therefore, when the load stress on the slab reaches the critical value of the design stress, it is necessary to grout the voided part in time to avoid slab damage.

[0070] Due to different conditions such as geology, load, and backstage treatment methods, with the long-term use of the road, voiding may continue to occur and multiple grouting treatments are required.

[0071] The traditional treatment method requires drilling and grouting on the slab. First, the construction affects traffic. Second, drilling needs to damage the asphalt concrete surface layer on the slab. After damage, the asphalt surface layer needs to be milled and then re-paved. Third, the construction period is long, the cost is high, and there are safety hazards.

[0072] Therefore, for the grouting one-way valve device described in the present invention, preferably, it is composed of a separate grouting steel pipe, a slab grouting reserved hole, a wedge-shaped cork, and a sealing rubber pad. The grouting steel pipe is led from the grouting reserved hole to both sides of the bridgehead subgrade. During grouting, grouting construction is carried out on both sides of the subgrade, without damaging the asphalt surface layer and not affecting vehicle traffic. After grouting, the pipeline is filled with slurry. After solidification, the pipeline cannot be reused again. Therefore, multiple grouting one-way valve devices are provided. During grouting, the pressure is from bottom to top. The setting of the wedge-shaped cork can prevent the slurry from entering the unused grouting steel pipe, thus ensuring that multiple groutings can be carried out.

[0073] In addition, the present invention also provides a construction method for a high-fill bridgehead anti-voiding precast prestressed slab structure, including the following steps:

[0074] 1) Prefabrication: Prefabricate precast slab group A (2) and precast slab group B (3). The precast slab group A (2) reserves corrugated steel strands (20), and strain gauges (13) are embedded on the longitudinal structural steel bars (16) at the bottom of the precast slab group A (2). Pressure sensor installation grooves are reserved at the corresponding positions at the bottom of the slab. The precast slab group A (2) is provided with slab grouting reserved holes (15);

[0075] 2) Tensioning and grouting: After the concrete strength of the precast slab group A (2) reaches 100%, the steel strands (23) are tensioned and grouted;

[0076] 3) Scarifying: Scarify the wet joint (4) sides of the precast slab group A (2) and the precast slab group B (3);

[0077] 4) Installation of pressure sensor: Remove the formwork of the reserved installation groove of the precast slab group A (2), install the pressure sensor (14) in the installation groove, and after adjusting the bearing surface at the bottom of the pressure sensor (14) to be flush with the bottom of the precast slab group A (2), fix the pressure sensor with structural adhesive;

[0078] 5) Installation of check valve: Clean the reserved grouting holes (15) on the precast slab, insert the wedge-shaped cork (17) into the grouting holes (15) of the slab from the bottom, and finally stick and seal the wedge-shaped cork (17) with a sealing rubber pad (18) at the bottom of the slab;

[0079] 6) Construction of the cushion layer for the pressure sensor: At the position of the pressure sensor (14) corresponding to the cushion layer of the slab, pre-cut a square groove of 50 cm × 50 cm × 2 cm on the subgrade (6), spread and compact the fine sand, and make the top surface of the fine sand flush with the surrounding cushion layer;

[0080] 7) Installation of precast slabs: Lay two layers of tarpaulins on the corbel (1) of the abutment, use a crane to install the precast slab group A (2), and fix one end of the precast slab group A (2) to the corbel (1) with anchor bolts, and then hoist the precast slab group B (3) to the predetermined position for installation;

[0081] 8) Connection of steel strands: Use a connector (9) to connect the embedded crimped steel strands (20) of the precast slab group A (2) with the steel strands (8) of the precast slab group B (3). Sleeve a plastic pipe (10) outside the connector (9). Seal the end of the plastic pipe (10) close to the precast slab group A (2), and seal and connect the end close to the precast slab group B (3) with the corrugated pipe (12) of the precast slab group B (3), and leave space for the tensioning and movement of the steel strand connector (9) at both ends of the plastic pipe (10);

[0082] 9) Construction of wet joints: Pour the longitudinal prestressed wet joint (4) and the ordinary concrete joint (24) connected by tie rods (5) horizontally at one time from one side of the bridge, and sprinkle water and cover for curing for 7 days;

[0083] 10) Tensioning of the precast slab group B (3): When the strength of the prestressed wet joint (4) reaches 100%, tension the steel strands of the precast slab group B (3), and grout and seal the anchor after tensioning;

[0084] 11) Treatment of expansion joints: Fill polyurethane asphalt at the expansion joint between the front wall (22) and the precast slab group A (2);

[0085] 12) Installation of grouting pipes: Connect the grouting steel pipe (19) with the reserved grouting holes (15) on the precast slab group A (2) and lead it to the outside of the slab at the bridge head.

[0086] Although the exemplary embodiments and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made to these embodiments without departing from the spirit of the invention and the scope of protection defined by the appended claims. For other examples, those of ordinary skill in the art should readily understand that the order of process steps can be varied while remaining within the scope of the invention.

[0087] In addition, the scope of application of the present invention is not limited to the processes, mechanisms, manufacturing, compositions of matter, means, methods, and steps of the specific embodiments described in the specification. From the disclosure of the present invention, those of ordinary skill in the art will readily understand that for processes, mechanisms, manufacturing, compositions of matter, means, methods, or steps that currently exist or will be developed in the future, and which perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described in the present invention, they can be applied in accordance with the present invention. Therefore, the appended claims of the present invention are intended to include these processes, mechanisms, manufacturing, compositions of matter, means, methods, or steps within their scope of protection.

Claims

1. Construction method of structure of high-fill bridgehead anti-separation precast prestressed slab, used for judgment and treatment of separation of bridgehead slab of high-fill subgrade. The structure includes the following three parts: Precast prestressed slab, which is set to be bolted to the bracket; One or more groups of monitoring devices, arranged at different positions of the slab, composed of a reinforcing bar stress gauge arranged on the upper part and a pressure sensor arranged on the lower part; Grouting check valve device, including grouting steel pipe, slab grouting reserved hole, wedge-shaped cork and sealing rubber pad, wherein the sealing rubber pad is arranged at the bottom of the slab; The precast prestressed slab further includes: Precast slab group A (2), precast slab group B (3) and prestressed wet joint (4) arranged along the length direction of the subgrade. Both precast slab group A (2) and precast slab group B (3) are composed of multiple laterally arranged concrete blocks. Adjacent laterally concrete blocks are connected by tie rods (5). One end of precast slab group A (2) is fixed to the bracket (1) of the abutment through anchor bolts, and the other end of precast slab group A (2) is connected to precast slab group B (3) through prestressed wet joint (4); It is characterized in that the construction method of the high-fill bridgehead anti-separation precast prestressed slab structure includes the following steps: 1) Prefabrication: Prefabricate precast slab group A (2) and precast slab group B (3). Precast slab group A (2) reserves corrugated steel strands (20), and strain gauges (13) are embedded on the longitudinal structural steel bars (16) at the bottom of precast slab group A (2). Pressure sensor installation grooves are reserved at corresponding positions at the bottom of the slab. Slab grouting reserved holes (15) are reserved on precast slab group A (2); 2) Tensioning and grouting: After the concrete strength of precast slab group A (2) reaches 100%, the steel strands (23) are tensioned and grouted; 3) Scarifying: Scarify the wet joint (4) sides of precast slab group A (2) and precast slab group B (3); 4) Pressure sensor installation: Remove the formwork of the reserved installation groove of precast slab group A (2), install the pressure sensor (14) in the installation groove. After adjusting the bottom bearing surface of the pressure sensor (14) to be flush with the bottom of precast slab group A (2), fix the pressure sensor with structural adhesive; 5) Check valve installation: Clean the reserved slab grouting reserved holes (15) on the precast slab, insert the wedge-shaped cork (17) into the slab grouting reserved hole (15) from the bottom, and finally stick and seal the wedge-shaped cork (17) with the sealing rubber pad (18) at the bottom of the slab; 6) Pressure sensor cushion construction: At the position of the pressure sensor (14) corresponding to the slab cushion, a square groove of 50 cm × 50 cm × 2 cm is pre-scarified on the subgrade (6), fine sand is paved and compacted, and the top surface of the fine sand is flush with the surrounding cushion; 7) Precast slab installation: Lay two layers of tarpaulins on the bracket (1) of the abutment, use a crane to install precast slab group A (2), and fix one end of precast slab group A (2) to the bracket (1) with anchor bolts, and then hoist precast slab group B (3) to the predetermined position for installation; 8) Steel strand connection: The pre-buried patterned steel strand (20) of the prefabricated panel group A (2) is connected to the steel strand (8) of the prefabricated panel group B (3) by using a connector (9), and a plastic tube (10) is sleeved on the outside of the connector (9). The end of the plastic tube (10) close to the prefabricated panel group A (2) is sealed, and the end close to the prefabricated panel group B (3) is sealed and connected to the corrugated tube (12) of the prefabricated panel group B (3), and space required for the steel strand connector (9) to be tensioned and moved is reserved at both ends of the plastic tube (10); 9) Wet joint construction: longitudinal prestressed wet joints (4) and transverse common concrete joints (24) connected by tie rods (5) are cast at one time on one side of the bridge, and then covered with water and cured for 7 days; 10) Precast panel group B (3) tensioning: When the strength of the prestressed wet joint (4) reaches 100%, the steel strands of the precast panel group B (3) are tensioned, and after the tensioning is completed, grouting and anchoring are performed; 11) Expansion joint treatment: Fill the expansion joint between the front wall (22) and the prefabricated panel group A (2) with polyurethane asphalt; 12) Installation of grouting pipe: Use a grouting steel pipe (19) to connect the reserved holes (15) for grouting on the slabs on the precast panel group A (2) and lead it to the bridgehead outside the slabs.

2. The construction method of the structure of the high fill bridge head anti-emptying assembled prestressed slab according to claim 1, It is characterized in that The prestressed wet joint (4) further comprises: The pre-buried wire strands (20) in the prefabricated panel group A (2), the wire strands (8), the connectors (9), the plastic pipes (10), the sealing sleeves (11), the corrugated pipes (12), and the wet joint concrete (21) in the prefabricated panel group B (3).

3. The construction method of the structure of the high fill bridge head anti-emptying assembled prestressed slab according to claim 1 or 2, It is characterized in that The monitoring device further comprises: It consists of a plurality of strain gauges (13) tied to the bottom longitudinal structural steel bars and a pressure sensor (14) pre-buried at a position vertically corresponding to the strain gauges (13) at the bottom of the slab.

4. The construction method of the structure of the high fill bridge head anti-emptying assembled prestressed slab according to claim 1 or 2, It is characterized in that The grouting one-way valve device further comprises: a grouting reserved hole (15) for the slab, a wedge-shaped cork plug (17), and a sealing rubber pad.

5. The construction method of the structure of the high fill bridge head anti-emptying assembled prestressed slab according to claim 1 or 2, It is characterized in that The prefabricated panel group A (2) has a thickness of 25 cm to 40 cm, a width adjusted according to the lane width, a length of 7 m to 8 m, a concrete grade of 40 Mpa to 50 Mpa, a steel strand diameter of 15.20 mm, and a strength of 1860 Mpa; and an anchor of the BJM15-3 series.

6. The construction method of the structure of the high fill bridge head anti-emptying assembled prestressed slab according to claim 1 or 2, It is characterized in that The steel strand reinforcement of the precast panel group A (2) is designed based on the existence of a certain length of gaps, with the target gap length being 4m to 5m.

7. Construction method of the structure of the high-fill bridgehead anti-void precast prestressed slab, according to claim 1 or 2, characterized in that, the thickness of the precast slab group B (3) is 25 cm to 40 cm, the width is adjusted according to the lane width, the length is determined according to the height of the backfill of the abutment, and the concrete grade is 40 Mpa to 50 Mpa; the diameter of the steel strand is 15.20 mm and the strength is 1860 Mpa; the anchor is of the BJM15-2 series.

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