Semi-filled and semi-excavated roadbed filling and excavation junction modular pulling structure and construction method

Abstract

The invention relates to the technical field of municipal road subgrade construction, in particular to a semi-filled and semi-excavated subgrade filling and excavation junction modular tying structure and a construction method.According to the technical scheme, the semi-filled and semi-excavated subgrade filling and excavation junction modular tying structure comprises a subgrade excavation area, a subgrade filling area is arranged on one side of the subgrade excavation area, and prefabricated blocks are arranged on one side of the subgrade excavation area; according to the construction method, the inserting holes are reserved in the excavation area of the roadbed, the anti-pulling anchor rods can be inserted into the inserting holes when the prefabricated blocks need to be installed, mortar is poured to form the first grouting layer, the high-strength mortar fills the splicing gaps between the modules and the gaps between the step faces and is maintained, then the prefabricated blocks are inserted into the anti-pulling anchor rods through the anchor rod holes, and then the prefabricated blocks are installed. The prefabricated blocks are fixed through the threaded heads and the nuts, the connecting strength of the roadbed excavation area and the roadbed filling area is enhanced through the multiple sets of prefabricated blocks, the shear strength can be effectively enhanced, differential settlement of the road surface after traffic opening is reduced, and the problem that in a traditional construction mode, the shear strength is prone to being insufficient is solved.

Description

Technical Field

[0001] This invention relates to the field of municipal roadbed construction technology, and in particular to a modular tie structure and construction method for the cut-fill junction of a semi-fill roadbed. Background Technology

[0002] Half-fill and half-cut roadbed construction is a type of road construction method. The cross-section of this roadbed consists of a cut area and a fill area. When necessary, the excavated soil from the cut area can be filled into the fill area and compacted to form a stable and uniform overall roadbed. This construction method is commonly used in mountainous road sections.

[0003] When constructing semi-fill and semi-cut roadbeds, the current industry generally adopts the traditional tie method of "step excavation + layered compaction". This method is prone to insufficient shear strength, so the settlement risk after construction using this method is high. In addition, it has defects such as difficulty in controlling the on-site construction quality, low construction efficiency and poor terrain adaptability. Therefore, this application proposes a modular tie structure and construction method for the fill-cut junction of semi-fill and semi-cut roadbeds. Summary of the Invention

[0004] The purpose of this invention is to address the problem that traditional construction methods in the background art are prone to insufficient shear strength, and to propose a modular tie structure and construction method for the cut-fill junction of a semi-fill roadbed.

[0005] In a first aspect, the technical solution of the present invention is as follows: a modular tie structure for the cut-fill junction of a semi-fill and semi-cut roadbed, comprising a roadbed cut area, a roadbed fill area on one side of the roadbed cut area, a precast block on one side of the roadbed cut area, an anchor bolt hole inside the precast block, an insertion hole on one side of the roadbed cut area, an anti-pull-out anchor bolt inserted into the anchor bolt hole of the precast block, one end of the anti-pull-out anchor bolt being inserted into the insertion hole, the diameter of the insertion hole being larger than the diameter of the anchor bolt hole, a first grouting layer being provided inside the insertion hole, the first grouting layer being provided on the outer wall of the anti-pull-out anchor bolt, a groove being provided on one side of the precast block, a threaded head being fixed to the other end of the anti-pull-out anchor bolt, the threaded head being located inside the groove, and a nut being threadedly connected to the outer wall of the threaded head.

[0006] Optionally, the precast block is made of cement, and a steel mesh is provided inside the precast block. A fastening block is fixed to one side of the precast block. The fastening block is wedge-shaped, and a fastening groove is provided on the other side of the precast block. The shape of the fastening groove is consistent with the shape of the fastening block.

[0007] Optionally, the precast block has drainage holes inside. One end of the drainage hole is located at the connection between the precast block and the roadbed excavation area. The drainage hole is located at the bottom of the groove. Multiple sets of drainage holes are provided and are distributed in parallel inside the precast block.

[0008] Optionally, a geogrid, which is a polyester geogrid, is provided at the bottom of the precast block.

[0009] Optionally, a geotextile is provided at the top of the roadbed filling area. The geotextile is made of non-woven fabric. A sand and gravel cushion layer is provided at the top of the geotextile and is placed at the bottom of the geogrid.

[0010] Optionally, a square plate is fixed to the outer wall of the pull-out anchor rod, and a fixing plate is fixed to the top and bottom of the square plate, with the precast block disposed between the two sets of fixing plates.

[0011] Optionally, a first bonding plate is fixed to one side of the roadbed excavation area, and a second bonding plate is fixed to one side of the precast block. The first bonding plate and the second bonding plate are bonded to each other, and both the first bonding plate and the second bonding plate are XPS boards.

[0012] Optionally, a fixing steel plate is provided inside the groove. The fixing steel plate is located at the connection of the two sets of precast blocks. Two sets of round holes are opened on one side of the fixing steel plate. The fixing steel plate is located on the outer wall of the threaded head through the round holes.

[0013] Optionally, the inner wall of the groove is filled with a second grout layer, which covers the outside of the threaded head and the nut.

[0014] Secondly, a modular construction method for the cut-fill junction of a semi-fill / semi-cut roadbed is applied to the modular tie-up structure at the cut-fill junction of the semi-fill / semi-cut roadbed described in the first aspect. This method includes the following steps:

[0015] S1. A geotextile is laid on top of the roadbed fill area, and a sand and gravel cushion layer is laid on the geotextile. The combination of geotextile and sand and gravel cushion layer can improve the overall tensile strength. A geogrid is installed on the top of the sand and gravel cushion layer to improve the tensile strength and facilitate the subsequent installation of precast blocks.

[0016] S2. Drill holes in the excavated area of ​​the roadbed and insert one end of the pull-out anchor into the holes. After the pull-out anchor is installed, mortar can be injected into the holes until the mortar solidifies to form the first grouting layer. The first grouting layer fills the gap between the holes and the pull-out anchor, making the pull-out anchor installed firmly.

[0017] S3. Align the anchor holes on the precast block with the pull-out anchor rod, and fit the precast block through the anchor holes onto the outside of the pull-out anchor rod until the threaded head of one end of the pull-out anchor rod extends into the groove. The precast block can be fixed in position by screwing a nut onto the threaded head.

[0018] S4. When splicing two sets of adjacent precast blocks, the fastening block on one set of precast blocks can be inserted into the fastening groove of the other set of precast blocks to connect the two sets of precast blocks. At the same time, a fixing steel plate is installed in the groove of the two sets of precast blocks so that the fixing steel plate is installed on the two sets of adjacent threaded heads and the fixing steel plate is installed firmly by nuts.

[0019] S5. After the precast blocks are installed, use high-strength mortar to fill the joints between the precast blocks, as well as the gaps between the precast blocks and the roadbed excavation and filling areas. Then, cure the solidified mortar. After the solidified mortar has reached the required strength, fill the roadbed filling area in layers and compact it to complete the construction of the roadbed cut-fill interface.

[0020] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0021] This invention, by pre-drilling holes in the excavated area of ​​the roadbed, allows for the insertion of pull-out anchors into the holes when precast blocks need to be installed. Mortar is then injected to form the first grouting layer, and high-strength mortar fills the gaps between the modules and the steps, and is cured. Subsequently, the precast blocks are inserted into the pull-out anchors through the anchor holes and fixed with threaded heads and nuts. By using multiple sets of precast blocks, the connection strength between the excavated and filled areas of the roadbed is enhanced, effectively increasing shear strength, reducing differential settlement of the road surface after traffic, and solving the problem of insufficient shear strength in traditional construction methods. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a modular tie-up structure at the cut-fill junction of a semi-fill roadbed.

[0023] Figure 2 This is a schematic cross-sectional view of a modular tie-up structure at the cut-fill junction of a semi-fill roadbed.

[0024] Figure 3 for Figure 2 An enlarged structural diagram at point A;

[0025] Figure 4 for Figure 2 An enlarged structural diagram at point B;

[0026] Figure 5 A schematic diagram of a prefabricated block structure for a modular tie-up structure at the cut-fill junction of a semi-fill roadbed;

[0027] Figure 6This is a schematic diagram of the connection between two sets of precast blocks in a modular tie-up structure at the cut-fill junction of a semi-fill roadbed.

[0028] Figure 7 A schematic diagram of a square plate and a fixing plate structure for a modular tie-down structure at the cut-fill junction of a semi-fill roadbed;

[0029] Figure 8 This is a schematic diagram of a geogrid structure for a modular tie-down structure at the cut-fill junction of a semi-fill roadbed.

[0030] Reference numerals in the attached drawings: 1. Roadbed excavation area; 2. Roadbed filling area; 3. Precast block; 4. Anti-pull-out anchor; 5. Threaded head; 6. Nut; 7. First grouting layer; 8. Groove; 9. Fastening block; 10. Fastening groove; 11. Drainage hole; 12. Geogrid; 13. Sand and gravel cushion layer; 14. Geotextile; 15. Square plate; 16. Fixing plate; 17. First bonding plate; 18. Second bonding plate; 19. Fixing steel plate; 20. Round hole; 21. Second grouting layer. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1 - Figure 5As shown, this invention proposes a modular tie-in structure for the cut-fill junction of a semi-cut and semi-fill roadbed, comprising a roadbed cut area 1, a roadbed fill area 2 on one side of the roadbed cut area 1, and a precast block 3 on one side of the roadbed cut area 1. Anchor bolt holes are formed inside the precast block 3, and insertion holes are formed on one side of the roadbed cut area 1. When roadbed construction is required, the roadbed cut area 1 and the roadbed fill area 2 can be compacted, and the roadbed fill area 2 can be compacted. In the excavation area 1, insertion holes are drilled. Pull-out anchor rods 4 are inserted into the anchor holes of the precast blocks 3, with one end of the anchor rod 4 inserted into the insertion hole. The diameter of the insertion hole is larger than the diameter of the anchor hole. A first grouting layer 7 is provided inside the insertion hole, located on the outer wall of the pull-out anchor rod 4. After the pull-out anchor rod 4 is inserted into the insertion hole, high-strength mortar can be injected into the insertion hole to coat the pull-out anchor rod. Between the anchor rod 4 and the insertion hole, until the mortar solidifies, the pull-out anchor rod 4 can be firmly installed in the roadbed excavation area 1. A groove 8 is opened on one side of the precast block 3, and a threaded head 5 is fixed to the other end of the pull-out anchor rod 4. The threaded head 5 is located inside the groove 8, and a nut 6 is threaded to the outer wall of the threaded head 5. The precast block 3 is placed on one side of the roadbed excavation area 1, so that the anchor rod hole on the precast block 3 is aligned with the pull-out anchor rod 4, so that the end of the pull-out anchor rod 4 with the threaded head 5 is inserted into the anchor rod hole of the precast block 3, and the threaded head 5 passes through the groove 8. Then, the nut 6 is tightened to fix the precast block 3 on the pull-out anchor rod 4. Multiple sets of precast blocks 3 are arranged and installed on one side of the roadbed excavation area 1 in sequence. At the same time, the precast blocks 3 are placed on the top of the roadbed filling area 2. Therefore, multiple sets of precast blocks 3 can enhance the connection strength between the roadbed excavation area 1 and the roadbed filling area 2, and can effectively enhance the shear strength.

[0033] like Figure 5 and Figure 6 As shown, the precast block 3 is made of cement and has a steel mesh inside. The steel mesh, combined with the cement material, further enhances the strength of the precast block 3. A snap-fit ​​block 9 is fixed to one side of the precast block 3. The snap-fit ​​block 9 is wedge-shaped. A snap-fit ​​groove 10 is provided on the other side of the precast block 3. The shape of the snap-fit ​​groove 10 is the same as that of the snap-fit ​​block 9. When two adjacent sets of precast blocks 3 need to be connected, the snap-fit ​​block 9 on one set of precast blocks 3 can be inserted into the snap-fit ​​groove 10 on the other set of precast blocks 3. Since both the snap-fit ​​block 9 and the snap-fit ​​groove 10 are wedge-shaped, after the snap-fit ​​block 9 is inserted into the snap-fit ​​groove 10, the two sets of precast blocks 3 can be locked together through their cooperation, preventing the horizontal position of the two sets of adjacent precast blocks 3 from changing.

[0034] like Figure 5 and Figure 6As shown, the precast block 3 has drainage holes 11 inside. One end of the drainage hole 11 is located at the connection between the precast block 3 and the roadbed excavation area 1. The drainage hole 11 is located at the bottom of the groove 8. There are multiple sets of drainage holes 11, which are distributed in parallel inside the precast block 3. By providing drainage holes 11 inside the precast block 3, when water seeps into the gap between the roadbed excavation area 1 and the precast block 3, it is easy to drain the water through the drainage holes 11, preventing excessive water accumulation between the roadbed excavation area 1 and the precast block 3.

[0035] like Figure 4 , Figure 5 and Figure 8 As shown, a geogrid 12 is provided at the bottom of the precast block 3. The geogrid 12 is a polyester geogrid. By setting the geogrid 12 on the precast block 3, the lateral soil expansion force caused by vertical load can be converted into its own tensile force through the tension force and mesh structure of the geogrid 12, thereby generating lateral restraint on the soil and significantly improving the tensile and shear strength of the subgrade, enabling it to withstand greater loads without easily failing. A geotextile 14 is provided at the top of the subgrade fill area 2. 14 is made of non-woven fabric. A sand and gravel cushion layer 13 is provided at the top of the geotextile 14. By setting the non-woven geotextile 14, the soft soil below and the sand and gravel cushion layer 13 can be isolated to prevent them from mixing, thereby improving the overall tensile strength. The sand and gravel cushion layer 13 is set at the bottom of the geogrid 12. By setting the sand and gravel cushion layer 13, pore water in the soft clay can be drained quickly, accelerating consolidation. The sand and gravel cushion layer 13 can also disperse the load above and reduce stress concentration on the soft clay below.

[0036] like Figure 3 and Figure 7 As shown, a square plate 15 is fixed to the outer wall of the pull-out anchor rod 4. After the precast block 3 is inserted into the pull-out anchor rod 4 through the anchor rod hole, the square plate 15 can be used to limit one side of the precast block 3. The top and bottom of the square plate 15 are fixed with fixing plates 16. The precast block 3 is placed between the two sets of fixing plates 16. The two sets of fixing plates 16 above and below the square plate 15 can limit the top and bottom of the precast block 3, which is conducive to the lateral fixed installation of the precast block 3.

[0037] like Figure 3As shown, a first bonding plate 17 is fixed to one side of the roadbed excavation area 1, and a second bonding plate 18 is fixed to one side of the precast block 3. The first bonding plate 17 and the second bonding plate 18 are bonded to each other. Both the first bonding plate 17 and the second bonding plate 18 are XPS boards. In cold winter weather, water seeping into the space between the roadbed excavation area 1 and the precast block 3 will quickly freeze into ice. Since the first bonding plate 17 and the second bonding plate 18 are provided between the roadbed excavation area 1 and the precast block 3, and both are XPS boards, they can absorb the displacement caused by the frost heave of the foundation through their own elastic compression deformation, and prevent the frost heave caused by freezing from increasing the gap between the roadbed excavation area 1 and the precast block 3.

[0038] like Figure 5 and Figure 6 As shown, a fixing steel plate 19 is provided inside the groove 8. The fixing steel plate 19 is set at the connection of the two sets of precast blocks 3. After the two sets of adjacent precast blocks 3 are fixed in position by the fastening block 9 and the fastening groove 10, the fixing steel plate 19 can be placed into the groove 8. Two sets of round holes 20 are opened on one side of the fixing steel plate 19. The fixing steel plate 19 is set on the outer wall of the threaded head 5 through the round holes 20. The two sets of round holes 20 are sleeved on the two sets of threaded heads 5 adjacent to the two sets of precast blocks 3, and the nut 6 is screwed on the threaded head 5 until the position of the fixing steel plate 19 is fixed. The fixing steel plate 19 can reinforce both sides of the connection of the two sets of precast blocks 3 and prevent longitudinal displacement of the two sets of precast blocks 3.

[0039] like Figure 4 As shown, the inner wall of the groove 8 is filled with a second grouting layer 21. The second grouting layer 21 covers the outside of the threaded head 5 and the nut 6. After the installation of multiple sets of precast blocks 3, mortar is injected into the groove 8 until the mortar solidifies to form the second grouting layer 21, which can seal the groove 8 and improve the stability of the nut 6 and the pull-out anchor rod 4.

[0040] A modular construction method for the cut-fill junction of a semi-fill / semi-cut roadbed, applied to the aforementioned modular tie structure at the cut-fill junction of a semi-fill / semi-cut roadbed, includes the following steps:

[0041] S1. A geotextile 14 is laid on top of the roadbed filling area 2, and a sand and gravel cushion layer 13 is laid on the geotextile 14. The combination of geotextile 14 and sand and gravel cushion layer 13 can improve the overall tensile strength. A geogrid 12 is installed on the top of the sand and gravel cushion layer 13 to improve the tensile strength and facilitate the subsequent installation of precast blocks 3.

[0042] S2. Drill holes in the roadbed excavation area 1 and insert one end of the pull-out anchor 4 into the holes. After the pull-out anchor 4 is installed, mortar can be injected into the holes until the mortar solidifies to form the first grouting layer 7. The first grouting layer 7 fills the gap between the holes and the pull-out anchor 4, making the pull-out anchor 4 installed firmly.

[0043] S3. Align the anchor bolt hole on the precast block 3 with the pull-out anchor bolt 4, and fit the precast block 3 through the anchor bolt hole onto the outside of the pull-out anchor bolt 4 until the threaded head 5 at one end of the pull-out anchor bolt 4 extends into the groove 8. The nut 6 can be screwed onto the threaded head 5 to fix the position of the precast block 3.

[0044] S4. When splicing two sets of adjacent precast blocks 3, the fastening block 9 on one set of precast blocks 3 can be inserted into the fastening groove 10 of the other set of precast blocks 3 to connect the two sets of precast blocks 3. At the same time, a fixing steel plate 19 is installed in the groove 8 of the two sets of precast blocks 3 so that the fixing steel plate 19 is installed on the two sets of adjacent threaded heads 5 and the fixing steel plate 19 is installed firmly by the nut 6.

[0045] S5. After the precast blocks 3 are installed, use high-strength mortar to fill the joints between the precast blocks 3, as well as the gaps between the precast blocks 3 and the roadbed excavation area 1 and the roadbed filling area 2. Then, cure the solidified mortar. After the solidified mortar has qualified strength, fill the roadbed filling area 2 in layers and compact it to complete the construction of the roadbed cut-fill interface at this location.

[0046] Working Principle: To address the issue of insufficient shear strength in traditional construction methods, when roadbed construction is required, the excavation area 1 and the filling area 2 of the roadbed can be compacted. Holes are drilled in the excavation area 1, and one end of the pull-out anchor 4 is inserted into the hole. After the pull-out anchor 4 is inserted, high-strength mortar is poured into the hole, covering the space between the pull-out anchor 4 and the hole, until the mortar solidifies to form the first grouting layer 7. This allows the pull-out anchor 4 to be securely installed in the excavation area 1. Subsequently, precast blocks 3 are placed on the roadbed. On one side of the excavation area 1, align the anchor holes on the precast block 3 with the pull-out anchor 4. This allows the threaded end of the pull-out anchor 4 to be inserted into the anchor hole of the precast block 3, with the threaded end 5 penetrating into the groove 8. The square plate 15 limits the position of one side of the precast block 3. Two sets of fixing plates 16 above and below the square plate 15 limit the top and bottom of the precast block 3, facilitating the lateral fixation of the precast block 3. Then, tighten the nuts 6 to fix the precast block 3 onto the pull-out anchor 4. This process is repeated for multiple sets of precast blocks 3. Arranged and installed on one side of the roadbed excavation area 1, the fixing steel plate 19 is placed into the groove 8 and fitted onto the two sets of adjacent threaded heads 5 of the two sets of precast blocks 3 through two sets of round holes 20. Nuts 6 are then screwed onto the two sets of adjacent threaded heads 5 until the position of the fixing steel plate 19 is fixed. The fixing steel plate 19 can reinforce both sides of the connection between the two sets of precast blocks 3 and prevent longitudinal displacement of the two sets of precast blocks 3. Since the precast blocks 3 are set on the top of the roadbed filling area 2, multiple sets of precast blocks 3 can be used to reinforce the roadbed excavation area 1 and the roadbed. The connection strength of the fill area 2 can effectively enhance the shear strength. The precast block 3 is equipped with a steel mesh inside, which can be used in conjunction with cement to further improve the strength of the precast block 3. When two adjacent sets of precast blocks 3 need to be connected, the snap-fit ​​block 9 on one set of precast blocks 3 can be snapped into the snap groove 10 on the other set of precast blocks 3. Since both the snap-fit ​​block 9 and the snap groove 10 are wedge-shaped, after the snap-fit ​​block 9 is snapped into the snap groove 10, the two sets of precast blocks 3 can be locked together through their cooperation, preventing the horizontal position of the two sets of adjacent precast blocks 3 from changing.

[0047] By setting geogrid 12 on precast block 3, the lateral soil expansion force caused by vertical load can be converted into its own tensile force through the tension force and grid structure of geogrid 12, thereby generating lateral restraint on the soil and significantly improving the tensile and shear strength of the subgrade, enabling it to withstand greater loads without easily being damaged. By setting sand and gravel cushion layer 13, pore water in soft clay can be quickly drained and consolidation accelerated. Sand and gravel cushion layer 13 can also disperse the load above and reduce stress concentration on the soft clay below. By setting non-woven geotextile 14, the soft soil below can be isolated from sand and gravel cushion layer 13 to prevent them from mixing, thereby improving the overall tensile strength.

[0048] When water seeps into the gap between the roadbed excavation area 1 and the precast block 3, it is easy to drain the water through the drainage hole 11 to prevent excessive water accumulation between the roadbed excavation area 1 and the precast block 3. In cold winter weather, the water seeping into the roadbed excavation area 1 and the precast block 3 will quickly freeze into ice. Since the first bonding plate 17 and the second bonding plate 18 are provided between the roadbed excavation area 1 and the precast block 3, and both are XPS plates, they can absorb the displacement caused by the frost heave of the foundation through their own elastic compression deformation, and prevent the frost heave caused by freezing from increasing the gap between the roadbed excavation area 1 and the precast block 3.

[0049] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A modular tie structure for the cut-fill junction of a semi-fill roadbed, comprising a roadbed cut area (1), wherein a roadbed fill area (2) is provided on one side of the roadbed cut area (1), characterized in that: A precast block (3) is provided on one side of the roadbed excavation area (1). An anchor hole is provided inside the precast block (3). An insertion hole is provided on one side of the roadbed excavation area (1). An anti-pull-out anchor (4) is inserted into the anchor hole of the precast block (3). One end of the anti-pull-out anchor (4) is inserted into the insertion hole. The diameter of the insertion hole is larger than the diameter of the anchor hole. A first grouting layer (7) is provided inside the insertion hole. The first grouting layer (7) is provided on the outer wall of the anti-pull-out anchor (4). A groove (8) is provided on one side of the precast block (3). A threaded head (5) is fixed to the other end of the anti-pull-out anchor (4). The threaded head (5) is provided inside the groove (8). A nut (6) is threadedly connected to the outer wall of the threaded head (5).

2. The modular tie-down structure at the cut-fill junction of a semi-fill / semi-cut roadbed according to claim 1, characterized in that, The precast block (3) is made of cement. The precast block (3) has a steel mesh inside. A fastening block (9) is fixed to one side of the precast block (3). The fastening block (9) is wedge-shaped. A fastening groove (10) is opened on the other side of the precast block (3). The shape of the fastening groove (10) is consistent with the shape of the fastening block (9).

3. A modular tie-down structure at the cut-fill junction of a semi-fill / semi-cut roadbed according to claim 2, characterized in that, The precast block (3) has drainage holes (11) inside. One end of the drainage hole (11) is located at the connection between the precast block (3) and the roadbed excavation area (1). The drainage hole (11) is located at the bottom of the groove (8). There are multiple sets of drainage holes (11) and they are distributed in parallel inside the precast block (3).

4. A modular tie-down structure for the cut-fill junction of a semi-fill roadbed according to claim 3, characterized in that, The bottom of the precast block (3) is provided with a geogrid (12), which is a polyester geogrid.

5. A modular tie-down structure at the cut-fill junction of a semi-fill / semi-cut roadbed according to claim 4, characterized in that, The top of the roadbed filling area (2) is provided with geotextile (14), which is made of non-woven fabric. The top of the geotextile (14) is provided with a sand and gravel cushion layer (13), which is located at the bottom of the geogrid (12).

6. A modular tie-down structure for the cut-fill junction of a semi-fill roadbed according to claim 5, characterized in that, The outer wall of the pull-out anchor rod (4) is fixed with a square plate (15), and the top and bottom of the square plate (15) are fixed with fixing plates (16). The precast block (3) is set between the two sets of fixing plates (16).

7. A modular tie-down structure for the cut-fill junction of a semi-fill roadbed according to claim 6, characterized in that, A first bonding plate (17) is fixedly connected to one side of the roadbed excavation area (1), and a second bonding plate (18) is fixedly connected to one side of the precast block (3). The first bonding plate (17) and the second bonding plate (18) are bonded to each other. Both the first bonding plate (17) and the second bonding plate (18) are XPS boards.

8. A modular tie-down structure at the cut-fill junction of a semi-fill / semi-cut roadbed according to claim 7, characterized in that, A fixing steel plate (19) is provided inside the groove (8). The fixing steel plate (19) is located at the connection of the two sets of precast blocks (3). Two sets of round holes (20) are opened on one side of the fixing steel plate (19). The fixing steel plate (19) is located on the outer wall of the thread head (5) through the round holes (20).

9. A modular tie-down structure at the cut-fill junction of a semi-fill / semi-cut roadbed according to claim 8, characterized in that, The inner wall of the groove (8) is filled with a second grout layer (21), which covers the outside of the threaded head (5) and the nut (6).

10. A modular construction method for the cut-fill junction of a semi-fill / semi-cut roadbed, applied to the modular tie structure at the cut-fill junction of a semi-fill / semi-cut roadbed as described in claim 9, characterized in that, The method includes the following steps: S1. A geotextile (14) is laid on top of the roadbed filling area (2), and a sand and gravel cushion layer (13) is laid on the geotextile (14). Through the combination of the geotextile (14) and the sand and gravel cushion layer (13), the overall tensile strength can be improved. A geogrid (12) is installed on the top of the sand and gravel cushion layer (13) to improve the tensile strength and facilitate the subsequent installation of precast blocks (3). S2. Drill holes in the roadbed excavation area (1) and insert one end of the pull-out anchor (4) into the holes. After the pull-out anchor (4) is installed, mortar can be injected into the holes until the mortar solidifies to form the first grouting layer (7). The first grouting layer (7) fills the gap between the holes and the pull-out anchor (4) to make the pull-out anchor (4) installed firmly. S3. Align the anchor hole on the precast block (3) with the pull-out anchor (4), and fit the precast block (3) through the anchor hole onto the outside of the pull-out anchor (4) until the threaded head (5) at one end of the pull-out anchor (4) extends into the groove (8). The nut (6) can be screwed onto the threaded head (5) to fix the position of the precast block (3). S4. When splicing two sets of adjacent precast blocks (3), the fastening block (9) on one set of precast blocks (3) can be inserted into the fastening groove (10) of the other set of precast blocks (3) to connect the two sets of precast blocks (3). At the same time, a fixing steel plate (19) is installed in the groove (8) of the two sets of precast blocks (3) so that the fixing steel plate (19) is installed on the two sets of adjacent threaded heads (5) and the fixing steel plate (19) is installed firmly by the nut (6). S5. After the precast blocks (3) are installed, high-strength mortar is used to fill the joint gaps between the precast blocks (3) and the gaps between the precast blocks (3) and the roadbed excavation area (1) and the roadbed filling area (2). The solidified mortar is cured. After the solidified mortar has qualified strength, the roadbed filling area (2) is filled in layers and compacted to complete the construction of the roadbed filling-excavation interface.

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