Anti-sedimentation foam light soil roadbed reinforcing structure

Abstract

The invention relates to an anti-settling foam light soil roadbed reinforcing structure, which belongs to the technical field of roadbed reinforcement, and comprises a foundation pretreatment layer and a foam light main body layer laminated on the foundation pretreatment layer, the foam light main body layer is connected with the bridge abutment through a telescopic part, a dynamic leveling layer is arranged at the bottom of the telescopic part, the dynamic leveling layer extends to the foam light main body layer from the bottom surface of the bridge abutment, and the dynamic leveling layer is used for forming opposite abutting force between the foam light main body layer and the bridge abutment; the dynamic leveling layer comprises a plurality of steel pipes arranged in the width direction of the roadbed and a cushion layer, the adjacent steel pipes are connected in a welded mode, and the cushion layer is provided with a plurality of steel pipe piles corresponding to the telescopic part to support the dynamic leveling layer steel pipe bridge abutment end pressed by the vehicle load, and the foundation pretreatment layer supports the steel pipe roadbed end to generate reverse elastic lifting. Compression settlement of the foam light soil layer is resisted, 'downward pressing-upward lifting 'dynamic balance is formed, uneven settlement of the bridge abutment and the roadbed can be effectively solved, and bumping at the bridge head is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of roadbed reinforcement, and in particular relates to an anti-settlement foam lightweight soil roadbed reinforcement structure. Background Art

[0002] In road and bridge engineering, the problem of roadbed settlement has always been a key factor restricting structural stability and driving safety. Although traditional roadbed reinforcement methods such as replacement, compaction and drainage consolidation can improve the bearing capacity of the roadbed to a certain extent, it is still difficult to effectively control post-construction settlement under complex geological conditions and long-term loads;

[0003] The bridge pile foundation is usually embedded in deep stable strata with minimal settlement. However, the abutment approach is mostly a fill roadbed, especially in soft soil areas. The fill section is prone to significant compression deformation under its own weight and traffic load. The settlement difference between the abutment and the approach can reach several centimeters, forming a "misaligned abutment".

[0004] The main body of the bridge is a rigid reinforced concrete structure, while the traditional fill used in the approach roadbed is a loose material. The difference in stiffness leads to uncoordinated load transfer. When vehicles pass through, the bridge deck has almost no deformation, while the roadbed filler produces a sudden step due to compression, causing the vehicle to jump.

[0005] The main body of the bridge is a rigid reinforced concrete structure with almost no deformation; while the asphalt pavement is a flexible layer that produces compressive deformation under load. When vehicles pass at high speed, the deformation of the bridge deck and the roadbed suddenly changes to form a "step effect".

[0006] It is urgent to construct an anti-settlement foam lightweight soil roadbed reinforcement structure to solve the problem of vehicle jumping at the bridge head. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides an anti-settlement foam lightweight soil roadbed reinforcement structure to solve the problem that the existing roadbed is prone to settlement under the action of vehicle loads and the vehicle jumps at the bridge head.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] An anti-settlement foam lightweight soil roadbed reinforcement structure comprises a foundation pretreatment layer and a foam lightweight main body layer stacked thereon; the foam lightweight main body layer is connected to an abutment through a telescopic portion, a dynamic leveling layer is arranged at the bottom of the telescopic portion, the dynamic leveling layer extends from the bottom surface of the abutment to the foam lightweight main body layer, and the dynamic leveling layer is used to form an opposite abutment force between the foam lightweight main body layer and the abutment;

[0010] The dynamic leveling layer includes a plurality of steel pipes and a cushion layer arranged along the width direction of the roadbed. The adjacent steel pipes are welded and connected. The cushion layer is supported by a plurality of steel pipe piles corresponding to the expansion and contraction parts.

[0011] Preferably, taking the telescopic part as the boundary, the proportion of the dynamic leveling layer in the abutment and the foamed lightweight main body layer is 1:2.5.

[0012] Preferably, the steel pipe is in a hollow shape. An isolation steel plate is arranged in any one of the steel pipes, and the adjacent two steel pipes are sealed. The isolation steel plate divides the steel pipe into an upper water guide layer and a lower water guide layer, and the water flow is discharged from the side by the two outermost steel pipes; the isolation steel plate is arranged in an inverted trapezoid shape in the steel pipe.

[0013] Preferably, a water guide pipe is further included. The water guide pipe is arranged at one end of the steel pipe located in the foamed lightweight main body layer and extends to the roadbed. The water guide pipe is used to connect a plurality of the steel pipes, and the axis of the water guide pipe is perpendicular to the axis of the steel pipe; a water guide groove is arranged along the axis of the water guide pipe, and the water guide groove is communicated with the steel pipe.

[0014] Preferably, both the upper water guide layer and the lower water guide layer are filled with filling stones with different diameters, and the diameter of the filling stones in the upper water guide layer gradually increases from bottom to top.

[0015] Preferably, the foamed lightweight soil main body layer is formed by pouring multiple layers of foamed cement-based materials. At least two layers of adjusting reinforcement meshes are embedded in the foamed lightweight soil main body layer. An adjusting mechanism is further included. The adjusting reinforcement meshes are anchored to the adjusting mechanism, and the adjusting mechanism is used to adjust the height of the adjusting reinforcement meshes in the vertical direction; the adjusting mechanism includes fixed concrete blocks, movable concrete blocks and jacking members. The fixed concrete blocks are poured and fixed on both sides of the foamed lightweight concrete layer. Any one of the movable concrete layers is arranged on the top of the fixed concrete blocks, and the jacking members are arranged between the fixed concrete layers and the movable concrete layers for jacking the movable concrete layers.

[0016] Preferably, the dynamic leveling layer further includes a stabilized crushed stone layer. The stabilized crushed stone layer is arranged between the foundation pre-treatment layer and the foamed lightweight main body layer, and the thickness of the stabilized crushed stone layer is greater than the thickness of the steel pipe.

[0017] Preferably, monitoring optical fibers and grouting pipes are embedded in the stabilized crushed stone layer; the monitoring optical fibers are buried in the stabilized crushed stone layer in a grid shape, and the ends of the optical fibers are connected to a data collector on the side wall of the roadbed. The grouting pipes are arranged in an S shape along the cross section of the roadbed, and a number of one-way grouting holes are arranged at intervals on the pipe body. A degradable rubber membrane is pasted outside the grouting holes. Both ends of the grouting pipes extend to the road shoulders and are provided with exposed interfaces with flange plates. The monitoring optical fibers are used to measure the settlement amount, and foamed lightweight soil slurry is injected into the grouting pipes from the exposed interfaces.

[0018] Preferably, the foundation pre-treatment layer includes a pile foundation array penetrating through the soft layer to the bearing layer and a composite cushion covering the pile tops.

[0019] The beneficial effects of the present invention are as follows:

[0020] Under the downward pressure of vehicle loads at the end of the steel pipe abutment of the dynamic leveling layer of this application, the foundation pre-treatment layer supports the end of the steel pipe subgrade to generate a reverse elastic uplift, resisting the compression settlement of the foamed lightweight soil layer, forming a "downward pressure - upward lift" dynamic balance, which can effectively solve the uneven settlement between the abutment and the subgrade and avoid the phenomenon of "bump at bridgehead"; the steel pipe can not only generate an anti-settlement force on the foamed lightweight main layer, but also isolate and discharge the subgrade water and groundwater, avoiding the foundation settlement caused by the seepage of the subgrade. Description of the Drawings

[0021] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the drawings.

[0022] Figure 1 It is a schematic structural diagram of a foamed lightweight soil subgrade reinforcement structure provided by the present invention in an embodiment;

[0023] Figure 2 It is a schematic structural diagram of the steel pipe arrangement provided by the present invention in an embodiment;

[0024] Figure 3 It is a schematic cross-sectional structural diagram of the connection between the steel pipe and the water guide pipe provided by the present invention in an embodiment;

[0025] Figure 4 It is a schematic structural diagram of the adjustment mechanism provided by the present invention in an embodiment;

[0026] Legend: 1. Foundation pre-treatment layer; 11. Pile foundation array; 2. Foamed lightweight main layer; 3. Dynamic leveling layer; 31. Steel pipe; 32. Water guide pipe; 321. Water guide groove; 33. Stable crushed stone layer; 34. Isolation steel plate; 41. Upper water guide layer; 42. Lower water guide layer; 5. Adjustment rib mesh; 6. Adjustment mechanism; 61. Fixed concrete block; 62. Movable concrete block; 63. Jacking member; 71. Monitoring optical fiber; 72. Grouting pipe; 8. Abutment. Detailed Embodiments

[0027] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in combination with the drawings and preferred embodiments, describe in detail the specific embodiments, structures, features and their effects of the present invention.

[0028] Conventional roadbeds are mostly filled with materials such as sand, gravel, and lime soil. Their compaction degree is restricted by construction techniques, and the materials themselves are prone to plastic deformation under the cyclic load of vehicles. As a rigid structure, the abutment 8 has extremely small settlement, while the flexible roadbed will have cumulative settlement under long-term load, resulting in a height difference at the connection between the two. Although existing technologies have tried to improve it by setting up a transition slab or strengthening compaction, the rigid connection between the transition slab and the roadbed is prone to fracture due to uneven settlement and is difficult to effectively solve the problem of bump at bridgehead.

[0029] As Figures 1 - 4 shown, an anti-settlement foam lightweight soil roadbed reinforcement structure is composed of a foundation pretreatment layer 1 and a foam lightweight main layer 2 from bottom to top to form a main bearing structure, and a dynamic leveling layer 3 is set at the connection with the abutment 8. The specific implementation method is as follows:

[0030] The dynamic leveling layer 3 is composed of steel pipes 31 arranged along the width direction of the roadbed, that is, the axis of the steel pipes 31 is consistent with the driving direction of the roadbed. Adjacent steel pipes 31 are connected by welds to form an integral lattice, and one end of the steel pipe 31 abuts against the space formed by the pile cap and the pier, and the other end extends to the foam lightweight main layer 2, realizing the transition connection between the abutment 8 and the roadbed through a number of steel pipes 31;

[0031] When a vehicle runs from the abutment 8 to the roadbed, the vehicle load acts on the abutment 8, generating a downward acting force on the abutment 8. Then, the steel pipes 31 and the end located at the abutment 8 are also subjected to downward acting forces. Under the combined action of the cushion layer and the steel pipes 31, the steel pipes 31 at the end of the foam lightweight main layer 2 tend to move upward, and thus can resist the downward load force and gravity of the foam lightweight main layer 2, reducing the uneven settlement amplitude between the foam lightweight main layer 2 and the abutment 8;

[0032] When the vehicle travels to the roadbed, the steel pipes 31 at the roadbed end are subjected to downward load, and the settlement amplitude is greater than that at the abutment 8 end. At this time, under the action of the cushion layer, the force direction of the steel pipes 31 at the abutment 8 end is changed to upward, abutting against the abutment 8 and resisting the downward settlement trend of the roadbed end at the same time, thereby reducing the uneven settlement amplitude between the abutment 8 and the roadbed;

[0033] At the same time, since one end of the steel pipe 31 is always located at the bottom of the abutment 8 protruding from the pier, when the vehicle runs from the abutment 8 to the roadbed, there are always steel pipes 31 as the transition connection between the abutment 8 and the roadbed, avoiding the rigid bridge deck directly changing to a flexible roadbed and increasing the possibility of uneven settlement of the roadbed;

[0034] The arrangement of the steel pipes 31 along the width direction of the roadbed can enhance the strength of the steel pipes 31 and better transmit and change the direction of the force, avoiding the arrangement of the steel pipes 31 along the vehicle driving direction, which may cause the interruption of the connection relationship between the steel pipes 31 and make it difficult to effectively transmit the resistance between the abutment 8 and the foam lightweight main layer 2.

[0035] In summary, under the downward pressure of vehicle loads on the abutment 8 end of the steel pipe 31 in the dynamic leveling layer 3 of the present application, the foundation pretreatment layer 1 supports the roadbed end of the steel pipe 31 to generate a reverse elastic lift, resisting the compression settlement of the foamed lightweight soil layer, forming a "downward pressure - upward lift" dynamic balance, which can effectively solve the uneven settlement between the abutment 8 and the roadbed and avoid "bump at bridgehead".

[0036] In order to have a relatively large abutting force for the steel pipe 31 in the area of the foamed lightweight main body layer 2 during the force transmission process and avoid damaging the abutment 8.

[0037] In an embodiment, the dynamic leveling layer 3 is divided along the roadbed extension direction into the abutment 8 connection section length L1 and the foamed lightweight main body layer 2 section length L2, and their ratio is 1:2.5, that is, L2 = 2.5L1. For example, when L1 = 1 m, L2 = 2.5 m, and the total length L = 3.5 m; the steel pipe 31 is integrally formed, and the loads generated by the same vehicle are the same. The abutting force of the steel pipe 31 on the abutment 8 and the foamed lightweight main body layer 2 is determined by the actual force arm length. Therefore, when the load is located on the abutment 8, the force arm length in the foamed lightweight main body layer 2 is long and the resistance is large, while when the load force is located in the foamed lightweight main body layer 2, the force arm on the abutment 8 is short and the abutting force generated on the abutment 8 is small; thus, the damage caused by the steel pipe 31 to the abutment 8 when bearing the load is small, while the anti - settlement force generated on the foamed lightweight main body layer 2 is large;

[0038] The abutment 8 connection section L1 bears the concentrated load transmitted by the abutment 8, avoiding stress mutation and realizing the initial load diffusion. The main body layer section length L2 can enhance the overall stiffness of the foamed lightweight main body layer 2 and realize the rigid transition between the abutment 8 and the foamed lightweight main body layer 2. Secondly, when the load acts on the abutment 8, a large - range support can be achieved in the foamed lightweight main body layer 2 through the main body layer section L2. When the load acts on the roadbed, the load force is dispersed through the main body layer section L2, and since the area of the main body layer section L2 is large, it can avoid excessive abutment between the steel pipe 31 and the abutment 8 when the steel pipe 31 has an upward movement tendency, thus damaging the abutment 8.

[0039] In addition to the uneven settlement of the roadbed caused by vehicle loads, water accumulation may also cause the collapse of the soil layer, and further cause the settlement of the roadbed; in one embodiment, the steel pipe 31 is in a hollow shape, and a partition steel plate 34 is arranged in any one of the steel pipes 31, and the adjacent two steel pipes 31 are sealed. The partition steel plate 34 divides the steel pipe 31 into an upper water guide layer 41 and a lower water guide layer 42. The upper water guide layer 41 is used to collect and drain the seepage water on the surface layer of the roadbed, and the lower water guide layer 42 is used to drain the deep groundwater and drain the water from the side by the steel pipes 31 at the two outermost sides. The partition steel plate 34 can prevent the surface water from infiltrating downward and also prevent the groundwater from spreading upward, and can effectively isolate the surface seepage water and the groundwater, avoiding the harm caused by the superposition of the two to the foundation; the partition steel plate 34 is arranged in the steel pipe 31 in an inverted trapezoid shape, which is used to enhance the stress of the steel pipe 31 and optimize the water flow.

[0040] In one embodiment, a water guide pipe 32 is further included. The water guide pipe 32 is arranged at one end of the steel pipe 31 located in the foam lightweight main body layer 2 and extends to the roadbed. The water guide pipe 32 is used to connect several of the steel pipes 31. The water guide pipe 32 is cylindrical. When generating resistance, it can evenly disperse the stress on the foam lightweight main body layer 2 and avoid damaging the structure of the foam lightweight main body layer 2. The axis of the water guide pipe 32 is perpendicular to the axis of the steel pipe 31. The water guide pipe 32 is provided with a water guide groove 321 along the axis. The water guide groove 321 is communicated with the steel pipe 31. That is, the water guide pipe 32 is at one end of several steel pipes 31 located in the foam lightweight main body layer 2, and a water guide groove 321 for communicating several steel pipes 31 is arranged inside. When the foam lightweight main body layer 2 settles, several steel pipes 31 will also settle accordingly, resulting in a situation where one end of the abutment 8 is high and one end of the foam lightweight main body layer 2 is low. At this time, under the action of the water guide groove 321, the water generated in the roadbed can gather towards the water guide pipe 32 and be discharged from both ends of the water guide pipe 32. The water guide pipe 32 can not only disperse the stress of the foam lightweight roadbed, but also play a role in drainage; of course, the water guide pipe 32 can be formed by concrete pouring, or can be supported by a metal material with sufficient hardness and all solid inside except for the water guide groove 321.

[0041] In one embodiment, both the upper water guide layer 41 and the lower water guide layer 42 are filled with filling stones with different diameters. The diameter of the filling stones in the upper water guide layer 41 gradually increases from bottom to top. Specifically, the diameter of the filling stones increases in three levels from 10 mm → 20 mm → 30 mm from bottom to top, forming a porosity gradient layer. The surface water quickly infiltrates to the 20-mm stone layer through the 30-mm stone layer, forming a gas-liquid two-phase flow in the gaps between the stones and reducing the water flow resistance.

[0042] In one embodiment, a layered pouring process is used to construct the main layer of foamed lightweight soil. Each layer is formed by pouring a foamed cement-based material. An adjustable rib mesh 5 is horizontally embedded at a preset elevation. The adjustable rib mesh 5 is a steel mesh or a high-strength fiber mesh. An anchoring section is reserved at its edge, and anchoring nodes are formed at at least two different heights. Fixed concrete blocks 61 are simultaneously poured at the edge positions on both sides of the main layer of foamed lightweight soil. The fixed concrete blocks 61 are consolidated into one with the main layer, and anchoring pieces are pre-embedded at the top. A movable concrete block 62 is pre-set on the top of the fixed concrete block 61. The edge anchoring sections of each layer of the adjustable rib mesh 5 are respectively connected to the movable concrete blocks 62 at the corresponding height. The connection method is a detachable bolt fixation or a reserved slot connection.

[0043] During the roadbed operation stage, the settlement of the main layer of foam lightweight soil and the bridge head joint area is monitored in real time through settlement observation equipment. When uneven settlement of the main layer is detected and the settlement difference is close to the design allowable value, the adjustment mechanism 6 is started. The jacking member 63 is a hydraulic jack or a mechanical screw jack, the bottom end of which is fixed to the embedded part of the fixed concrete block 61, and the top end supports the bottom surface of the movable concrete block 62. By synchronously operating the jacking member 63, the movable concrete block 62 is driven to move in the vertical direction, driving the anchored adjustment reinforcement mesh 5 to be lifted upward to compensate for the settlement.

[0044] This embodiment pre-buries the detachable regulating mechanism 6 to realize active lifting control of the regulating reinforcement mesh 5 after the main layer of the foam lightweight soil settles, and directly performs dynamic compensation for the uneven settlement problem.

[0045] In one embodiment, the dynamic leveling layer 3 further includes a stable crushed stone layer 33, which is arranged between the foundation pretreatment layer 1 and the foam lightweight main body layer 2. The thickness of the stable crushed stone layer 33 is greater than the thickness of the steel pipe 31. After the foundation pretreatment layer 1 completes site leveling and soft foundation reinforcement, the stable crushed stone layer 33 with a thickness greater than the steel pipe 31 is laid. The crushed stone layer forms a high modulus transition layer through the skeleton-interlocking effect of the graded crushed stone, which can be used to stabilize the upper foam lightweight soil main body layer and the traffic load The vertical stress of the load is diffused laterally to the foundation, reducing the risk of additional stress concentration in the foundation; the design of the crushed stone layer thickness exceeding the diameter of the steel pipe 31 can form a wrapping protective layer for the embedded steel pipe 31, avoiding the puncture damage of the end of the steel pipe 31 due to uneven settlement of the foundation, and preventing the interface stress concentration caused by direct contact between the steel pipe 31 and the foam lightweight soil; the internal pores of the crushed stone layer constitute a three-dimensional drainage channel, which is linked with the drainage system in the foundation pretreatment layer 1 to accelerate the dissipation of excess pore water pressure during the construction period and promote foundation consolidation. During the operation period, rainwater and groundwater can be quickly drained to maintain a dry environment at the bottom of the main layer of the foam lightweight soil and reduce the strength attenuation caused by water damage.

[0046] Traditional subgrade settlement monitoring relies on artificial observation points or single-point sensors, making it difficult to capture local differential settlements at the interface between the stable crushed stone layer 33 and the foamed light soil.

[0047] In one embodiment, the grid-shaped monitoring optical fiber 71 senses the deformation of the crushed stone layer through the Brillouin scattering effect. When settlement occurs, the axial strain of the monitoring optical fiber 71 causes a change in the frequency of the optical signal. The data acquisition instrument inversely calculates the settlement value by demodulating the change amount of the optical signal. The acquisition instrument is internally provided with a threshold comparison module. When the settlement amount of the grid exceeds the design allowable value, a grouting signal is sent.

[0048] The grouting pipe 72 is arranged in an S shape. Unidirectional grouting holes with a diameter of φ3mm are opened at intervals on the pipe body, and a degradable rubber membrane is pasted at the hole opening. The degradation period is 6 - 12 months. In the initial stage, the membrane body is closed to prevent crushed stone from invading. After the membrane body degrades during the operation period, the slurry is ejected along the tangential direction of the hole opening under the drive of pressure, forming a fan-shaped diffusion area.

[0049] The exposed interfaces at both ends of the grouting pipe 72 are connected to a double-fluid grouting pump. First, water glass slurry is injected to fill the pores of the crushed stone, and then foamed light soil slurry is injected to reinforce the soil. The foamed light soil slurry has a low density, which can avoid secondary settlement caused by the weight increase of traditional cement slurry.

[0050] In one embodiment, the foundation pretreatment layer 1 includes a pile foundation array 11 that penetrates through the soft layer to the bearing layer. Under the action of the subgrade load, the piles directly transfer the upper load to the bearing layer, and the bearing layer is used to bear the main stress to reduce the foundation settlement. The array composed of multiple piles expands the load diffusion range through the stress overlap area, avoiding differential settlement caused by the concentration of single-pile load. The soil between the piles is compacted due to compression, the void ratio decreases, and the shear strength increases, forming a composite foundation bearing mode.

[0051] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or equivalent changes and modifications within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An anti-settlement foam lightweight soil subgrade reinforcement structure, characterized in that It comprises a foundation pretreatment layer and a foam lightweight main body layer stacked thereon; the foam lightweight main body layer is connected to the abutment through a telescopic portion, a dynamic leveling layer is arranged at the bottom of the telescopic portion, the dynamic leveling layer extends from the bottom surface of the abutment to the foam lightweight main body layer, and the dynamic leveling layer is used to form an opposite abutment force between the foam lightweight main body layer and the abutment; The dynamic leveling layer includes a plurality of steel pipes and a cushion layer arranged along the width direction of the roadbed. Adjacent steel pipes are welded and connected. The cushion layer is supported by a plurality of steel pipe piles corresponding to the expansion and contraction parts.

2. The anti-settlement foam lightweight soil subgrade reinforcement structure according to claim 1, characterized in that, Taking the expansion and contraction portion as the boundary, the ratio of the dynamic leveling layer between the abutment and the foam lightweight main body layer is 1:2.

5.

3. The anti-settlement foam lightweight soil subgrade reinforcement structure according to claim 1, characterized in that, The steel pipe is hollow in shape, and an isolation steel plate is arranged in any of the steel pipes, and the two adjacent steel pipes are sealed. The isolation steel plate divides the steel pipe into an upper water-conducting layer and a lower water-conducting layer, and the water flow is discharged from the sides by the steel pipes on the two sides; the isolation steel plate is arranged in an inverted trapezoidal shape on the steel pipe.

4. A subgrade reinforcement structure of anti-settlement foamed lightweight soil according to claim 3, characterized in that It also includes a water pipe, which is arranged at one end of the steel pipe located at the foam lightweight main body layer and extends to the roadbed. The water pipe is used to connect several of the steel pipes, and the axis of the water pipe is perpendicular to the axis of the steel pipe; the water pipe is provided with a water groove along the axis, and the water groove is connected to the steel pipe.

5. The anti-settlement foam lightweight soil subgrade reinforcement structure according to claim 3, characterized in that The upper water-conducting layer and the lower water-conducting layer are both filled with filling stones of different diameters, and the diameter of the filling stones in the upper water-conducting layer gradually increases from bottom to top.

6. The anti-settlement foam lightweight soil subgrade reinforcement structure according to claim 1, characterized in that The main layer of the foam lightweight soil is cast by multiple layers of foamed cement-based materials. The main layer of the foam lightweight soil is embedded with at least two layers of adjustable reinforcement mesh, and also includes an adjustment mechanism. The adjustable reinforcement mesh is anchored in the adjustment mechanism, and the adjustment mechanism is used to adjust the height of the adjustable reinforcement mesh in the vertical direction; the adjustment mechanism includes a fixed concrete block, a movable concrete block and a jacking piece. The fixed concrete block is cast and fixed on both sides of the foam lightweight concrete layer, and any movable concrete layer is arranged on the top of the fixed concrete block. The jacking piece is arranged between the fixed concrete layer and the movable concrete layer, and is used to jack up the movable concrete layer.

7. The anti-settlement foam lightweight soil subgrade reinforcement structure according to claim 1, characterized in that, The dynamic leveling layer also includes a stable crushed stone layer, which is arranged between the foundation pretreatment layer and the foam lightweight main body layer, and the thickness of the stable crushed stone layer is greater than the thickness of the steel pipe.

8. A subgrade reinforcement structure of anti-settlement foamed lightweight soil according to claim 6, characterized in that, Monitoring optical fibers and grouting pipes are pre-buried in the stable gravel layer; the monitoring optical fibers are buried in the stable gravel layer in a grid shape, and the ends of the optical fibers are connected to a data acquisition device on the side wall of the roadbed; the grouting pipes are arranged in an S shape along the cross section of the roadbed, and a number of one-way grouting holes are arranged at intervals on the pipe body, and a degradable rubber film is pasted on the outside of the grouting holes; both ends of the grouting pipes extend to the shoulders and are provided with exposed interfaces with flanges; the monitoring optical fibers are used to measure the amount of settlement, and foamed lightweight soil slurry is injected into the grouting pipes from the exposed interfaces.

9. The anti-settlement foam lightweight soil subgrade reinforcement structure according to claim 1, characterized in that The foundation pretreatment layer comprises a pile foundation array penetrating the weak layer to the bearing layer.

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