Layered waste filling retaining wall and widened embankment structure system and construction method

Abstract

The invention discloses a layered waste filling retaining wall and widened embankment structure system and a construction method, and relates to road reconstruction and extension projects. The system comprises a built-in structure arranged in an old embankment step through a built-in groove, and the built-in structure is connected to a retaining wall through a tie bar; a lower horizontal layer, an oval pipe and an upper covering layer are circularly stacked in a cavity between the inner wallboard and the outer wallboard, and mixed filler is formed in the oval pipe through primary filling of waste materials and secondary grouting of fine slurry; the widened embankment is composed of a gravel soil layer, a drainage cushion layer, lightweight concrete and a pavement structure, and drainage pipes are elastically fixed to tie bars through deformation frames and hanging bars. Reliable anchoring of the retaining wall and the old embankment, resource utilization of waste materials, rapid circulation forming of the filling structure and accurate limiting of the drainage pipe are achieved, and the construction efficiency and the overall stability of the structure are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, specifically to a structural system and construction method for widening and upgrading roadbeds or embankments in highway, railway and other line engineering projects, and in particular to a layered structural system and construction method for the coordinated construction of prefabricated retaining walls filled with waste materials and lightweight embankments. Background Technology

[0002] Embankment widening construction generally faces technical challenges such as narrow working space, tight schedule, and difficulty in controlling differential settlement between new and old roadbeds. At the same time, a large amount of construction waste and engineering spoil generated during the reconstruction and expansion process urgently need to be utilized as resources.

[0003] In existing embankment widening projects, retaining walls on the adjacent sides often employ gravity or cantilever structures, connected to the old embankment only by simple backfill or a few reinforcing bars. This lack of systematic embedding and anchoring means that under long-term embankment and traffic loads, relative displacement easily occurs at the junction of the retaining wall and the old embankment, leading to structural cracking, tilting, and other defects. While some technologies propose installing reinforcing bars at the steps of the old embankment, the anchoring methods at the ends of the reinforcing bars are simplistic, resulting in insufficient anchoring force. Furthermore, the connection points between the reinforcing bars and the inner wall panels of the retaining wall are complex, making it difficult to guarantee long-term collaborative performance. Regarding retaining wall construction materials, existing technologies mostly use precast blocks or cast-in-place concrete, which suffer from drawbacks such as heavy weight, long construction periods, and high material costs. A few technologies attempt to use waste materials for filling, but these often involve direct backfilling or simple wrapping, resulting in poor compaction and weak integrity of the fill material, failing to achieve effective collaboration between the waste material and the structure.

[0004] In terms of embankment widening and drainage construction, the drainage pipes in the drainage cushion layer are simply covered or partially tied and fixed by the cushion layer material. During subsequent processes such as gravel paving and lightweight concrete pouring, they are prone to displacement, floating or bending damage, resulting in drainage slope failure and pipe blockage. Although secondary adjustments can be made, it is time-consuming, laborious and has limited effect.

[0005] In addition, in existing embankment widening projects, the construction of retaining walls and embankment filling are often carried out independently in a sequential manner, lacking coordinated design and process connection at the structural level. The overall construction period is long, and there is a lack of systematic spatial coordination between the load-bearing components such as retaining wall ties and embedded structures and the embankment drainage pipes and filler layers.

[0006] In summary, the development of a new structural system and construction method that enables reliable anchoring of retaining walls to existing embankments, efficient filling of waste materials, rapid cyclic molding of filling structures, effective limiting of drainage pipes, and integrated collaborative construction of retaining walls and embankments has engineering application value. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a layered waste-filled retaining wall and embankment widening structure system and construction method. By constructing a waste-filled retaining wall to form an outer protective structure, the embankment is widened under the protection of the outer protective structure, thereby achieving the technical goals of construction safety, structural stability, waste utilization, and rapid prototyping.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A layered waste-filled retaining wall and widened embankment structure system includes steps opened on the old embankment, wherein the steps are provided with a fixing structure by means of an embedded groove formed by excavation; the fixing structure is connected to the retaining wall by a tie rod. The retaining wall is installed on the adjacent side of the embankment to be widened, and includes an inner wall panel and an outer wall panel. The inner wall panel and the outer wall panel are temporarily fixed by opposing ties to form a filling cavity. A wall toe beam is provided at the bottom of both the inner wall panel and the outer wall panel. Before installing the inner wall panel and the outer wall panel, a connecting frame is set in the soil under the preset wall toe beam, and the connecting frame is further strengthened by pouring a consolidation body to form the bottom anchoring structure of the retaining wall. A bottom sealing layer is filled between the inner wall panel and the outer wall panel. The filling structure between the inner wall panel and the outer wall panel is formed by stacking a lower layer, an elliptical tube and an upper covering layer in a cyclical manner; the shapes of the lower layer and the upper covering layer are adapted to the shape of the elliptical tube; the bottom of the elliptical tube is installed on a preset positioning pin through its own installation hole. The cavity formed by the elliptical tube is filled with a mixed filler material, which is formed by a two-stage filling process: the first filling is to fill the cavity of the elliptical tube with waste material, and the second filling is to install a grouting pipe at the top of the elliptical tube, so that the bottom of the grouting pipe extends into the waste material, and then inject fine grout through the grouting pipe. The fine grout penetrates and fills the pores of the waste material, and finally forms the mixed filler material. Furthermore, a suspended formwork is used to simultaneously pour the upper overlay layer corresponding to the lower elliptical tube and the lower sub-layer corresponding to the upper elliptical tube in one operation. The suspended formwork includes an arc-shaped formwork adapted to the shape of the elliptical tube, which is supported by suspension rods and suspension beams. The bottom of the suspension rods abuts against the lower elliptical tube that has already been installed. The arc-shaped formwork and the lower elliptical tube that has already been installed form a pouring cavity, and positioning pins for installing the upper elliptical tube are preset in the pouring cavity. Concrete is poured through the pouring port opened in the middle of the arc-shaped formwork, and the upper overlay layer of the lower elliptical tube and the lower sub-layer of the upper elliptical tube are poured in one operation. The top of the retaining wall is provided with a top sealing layer.

[0009] The embedding structure is connected to the retaining wall via tie bars. Specifically, one end of the tie bar is connected to a tie node on the inner side of the inner wall panel, and the other end of the tie bar is connected to the embedding structure. The embedding structure is installed in an embedding groove opened at the step. The embedding structure includes an embedding precast component installed in the embedding groove. The embedding precast component includes an arched rib and end anchor plates set at both ends of the arched rib. The end anchor plates are set in the anchoring end, and a connecting plate is provided between two adjacent anchoring ends. The embedding precast component is installed as a whole in the embedding groove and connected to the transition rib through the arched rib. The transition rib is connected to the anchoring pressure plate at the top of the embedding groove, and the lower part of the anchoring pressure plate is connected to the end of the tie bar. After construction in the remaining cavity of the embedding groove, anchoring concrete is poured to complete the installation and fixing of the embedding structure.

[0010] The widened embankment includes a gravel soil layer, a drainage cushion layer, lightweight concrete, and a pavement structure constructed sequentially within the area enclosed by the steps and the adjacent retaining wall of the old embankment; wherein a drainage pipe is installed in the drainage cushion layer.

[0011] Furthermore, to prevent the drainage pipe from shifting during construction, the drainage pipe and the tie rod are temporarily and elastically fixed. Specifically, a lifting ring and a lifting rod are installed on the tie rod, the bottom of which is connected to the deformable frame, and the deformable frame is connected to the drainage pipe. The deformable frame is assembled from multiple support rods connected by hinge shafts. Through the movement of the support rods relative to the hinge shafts, the deformable frame can change shape within a certain range during the embankment filling process when subjected to external loads, thereby avoiding rigid connection of the drainage pipe and simultaneously providing a connection and limiting function for the drainage pipe within a certain range, preventing excessive displacement of the drainage pipe.

[0012] A construction method for a layered waste-filled retaining wall and widened embankment structure system includes the following steps: Step 1: Construction of old embankment treatment and embedment structure S11. Excavation of old embankment steps and embedment trenches: Excavate steps on the old embankment to form steps, and form embedment trenches within the steps through excavation.

[0013] S12. Install and fix the precast component and tie rod: Install the precast component into the embedding groove; then connect and fix the arched reinforcement and the transition reinforcement, connect the other end of the transition reinforcement to the anchoring plate at the top of the embedding groove, and connect and fix the end of the tie rod to the lower part of the anchoring plate.

[0014] S13. Post-cast anchoring concrete construction: After constructing in the remaining cavity of the embedding groove, cast anchoring concrete to complete the installation and fixation of the embedding structure and form the embedding structure.

[0015] Step 2: Anchoring structure at the bottom of the retaining wall and installation of the wall body S21. Bottom Anchorage Structure Construction: Before installing the inner wall panels and outer wall panels, a connecting frame is set in the soil under the pre-set wall toe beam. The connecting frame is further strengthened by pouring solidified material to form the bottom anchorage structure of the retaining wall.

[0016] S22. Construction of wall toe beams, inner and outer wall panels and bottom sealing layer: Wall toe beams are set at the bottom of both inner and outer wall panels. The inner and outer wall panels are temporarily fixed by opposite tie-ins to form a filling cavity. The bottom end between the inner and outer wall panels is filled with a bottom sealing layer.

[0017] Step 3: Cyclic construction of the elliptical tube filling structure S31. Bottom structure construction: First, construct the bottommost subfloor and elliptical tube.

[0018] S32. Installation of suspended formwork and formation of pouring cavity: Install suspended formwork, which includes an arc-shaped formwork adapted to the shape of the elliptical tube. The arc-shaped formwork is supported by suspension rods and suspension beams. The bottom of the suspension rods abuts against the lower installed elliptical tube. The arc-shaped formwork and the lower installed elliptical tube enclose each other to form a pouring cavity.

[0019] S33. Positioning pin pre-setting and concrete pouring: Positioning pins for the installation of the upper elliptical tube are pre-set in the pouring cavity. Concrete is poured through the pouring port opened in the middle of the arc-shaped template to complete the upper cover layer of the lower elliptical tube and the lower back layer of the upper elliptical tube in one go.

[0020] S34. Elliptical tube installation and two-stage filling: The bottom of the elliptical tube is installed on the preset positioning pin through its own installation hole. Waste material is filled into the cavity formed by the elliptical tube to complete the first filling. A grouting pipe is set at the top of the elliptical tube so that the bottom of the grouting pipe extends into the waste material. Fine grout is injected through the grouting pipe so that the fine grout penetrates and fills the pores of the waste material, and finally forms a mixed filler.

[0021] S35. Cyclic Layer-by-Layer Construction: The lower layer, elliptical tube, and upper overlay layer are constructed in a cyclical manner, stacking layer by layer to form the filling structure between the inner wall panel and the outer wall panel.

[0022] S36. Top sealing of retaining wall: Construct a top sealing layer at the top of the retaining wall.

[0023] Step 4: Final Fixing of Tie Bars One end of the tie bar is connected to the tie node on the inner side of the inner wall panel, and the other end of the tie bar is connected to the lower part of the anchor plate, thus completing the construction of the embedded structure by connecting the tie bar to the retaining wall.

[0024] Step 5: Construction of widened embankment Within the area enclosed by the steps of the old embankment and the adjacent retaining wall, the widened embankment is constructed sequentially. The specific construction process is as follows: S51. Construction of Crushed Stone Soil Layer, Drainage Subbase, and Drainage Pipes: First, a crushed stone soil layer is laid within the enclosed area, with each layer being laid and compacted in layers. A drainage subbase is constructed on top of the crushed stone soil layer, and drainage pipes are installed within it. The installation position and slope of the drainage pipes strictly adhere to the design requirements. To prevent displacement of the drainage pipes during construction, temporary elastic fixation is applied to the tie rods. Specifically, this is achieved by installing lifting rings and lifting rods on the tie rods, connecting the bottom of the lifting rods to the deformation frame, which in turn connects to the drainage pipes. The deformation frame is composed of multiple support rods connected by hinge shafts. The movement of the support rods relative to the hinge shafts allows the deformation frame to change shape within a certain range during embankment filling when subjected to external loads. This avoids rigidly binding the drainage pipes and provides a limiting function for the drainage pipes within a certain range, preventing excessive displacement.

[0025] S52. Lightweight concrete construction: After the drainage cushion layer and drainage pipes are completed and accepted, lightweight concrete is constructed on top of the drainage cushion layer. During the pouring of lightweight concrete, it is vibrated and compacted in layers.

[0026] S53. Road structure construction: After the lightweight concrete reaches its design strength, the road structure is constructed on top of the lightweight concrete. The beneficial effects of this invention are as follows: (1) This invention creates an embedded groove within the steps of an old embankment and constructs an embedded structure within the groove, consisting of arched reinforcing bars, end anchor plates, anchoring ends, connecting plates, transition bars, anchoring pressure plates, and post-cast anchoring concrete. This forms a multi-level anchoring force transmission path, with the arched reinforcing bars and transition bars working together to effectively diffuse the tensile force at the ends of the reinforcing bars to the surrounding soil, thereby improving the anchoring bearing capacity. Compared with the traditional direct burial of reinforcing bars, this invention improves the pull-out bearing capacity of the embedded structure.

[0027] (2) This invention constructs a waste-filled retaining wall (composed of inner wall panels, outer wall panels and filling structure) as an external protective structure, which effectively isolates the junction of the new and old embankments and prevents the slope soil from sliding during construction. The embedded structure (including embedded groove, embedded prefabricated parts and tie bars) is anchored to the old embankment steps to form anti-sliding force and reduce the risk of embankment instability.

[0028] (3) An elliptical tube is used to enclose the cavity. Through a two-stage filling process of "one-time filling of waste materials + secondary infiltration grouting of fine slurry", the waste materials such as construction slag, engineering waste soil, and industrial waste are fully bonded with fine slurry to form a mixed filler. This process not only realizes the large-scale utilization of waste materials (volume content can reach 60% to 80%), but also significantly improves the density and integrity of the filler through the infiltration filling of fine slurry, making it both load-bearing and lightweight. Compared with the pure concrete filling scheme, the cost of retaining wall materials can be reduced.

[0029] (4) This invention constructs a temporary elastic fixing structure for the drainage pipe by setting up lifting rings, lifting rods, deformation frames, and hinge shafts on the tie rods. The deformation frame is composed of multiple support rods connected by hinge shafts and has adaptive deformation capability: when the drainage pipe is disturbed by external forces during the embankment filling process, such as the paving of crushed stone soil layer and the pouring of lightweight concrete, the deformation frame absorbs deformation and releases stress through the relative rotation of the support rods, avoiding rigid tie damage to the drainage pipe; at the same time, the tie limiting effect of the deformation frame can control the positional deviation of the drainage pipe within the allowable range. This structure is simple to construct and easy to install, requiring no additional supports or anchor points, which significantly improves the construction quality and efficiency of the drainage system.

[0030] (5) This invention integrates the construction of the retaining wall structure with the construction of the widened embankment through a systematic process of “first construction of the embedded structure → anchoring at the bottom of the retaining wall → cyclic construction of elliptical tube filling → final fixing of the tie rods → layered filling of the widened embankment”. The tie rods not only serve as force-transmitting components between the embedded structure and the inner wall panel, but also as installation carriers for the elastic fixing devices of the drainage pipes; the construction of the retaining wall filling structure and the construction of the gravel soil layer and drainage cushion layer of the widened embankment are carried out in a staggered manner in space and in parallel in time, forming a continuous operation.

[0031] (6) The present invention reinforces the soil under the wall toe beam by means of bottom anchoring structure (connecting frame + consolidation body), which significantly improves the retaining wall’s resistance to overturning and sliding.

[0032] (7) The present invention uses elliptical tubes to fill the internal mixed filler. The cross-sectional shape of the elliptical tubes has good compressive strength and arch effect, which can uniformly transfer the upper load to the lower layer. Attached Figure Description

[0033] Figure 1 A schematic diagram of the overall construction of the layered waste-filled retaining wall and widened embankment structure system; Figure 2 This is a schematic diagram of the embankment retaining wall construction. Figure 3 This is a schematic diagram of an elliptical tube; Figure 4 This is a schematic diagram of the lower bunk. Figure 5 This is a schematic diagram of the overlying layer; Figure 6 A schematic diagram of waste material being filled into an elliptical tube; Figure 7 This is a schematic diagram of post-grouting inside an elliptical tube; Figure 8 This is a schematic diagram of the final mixed filler material formed inside the elliptical tube. Figure 9 This is a schematic diagram of the embedded structure; Figure 10 This is a schematic diagram of the embedded prefabricated component structure; Figure 11 Schematic diagram for temporary fixing of drainage pipe; The attached diagram lists the components represented by each number as follows: In the diagram: 1. Old embankment; 2. Step; 3. Embedded groove; 4. Embedded structure; 5. Tie bar; 6. Inner wall panel; 7. Outer wall panel; 8. Toe beam; 9. Connecting frame; 10. Consolidated body; 11. Bottom sealing layer; 12. Underlying layer; 13. Elliptical tube; 14. Overburden layer; 15. Mixed filler; 16. Locating pin; 17. Tie joint; 18. Arch reinforcement; 19. End anchor plate; 20. Anchoring end; 21. Connecting plate; 22. 23. Transition bar; 24. Post-cast anchoring concrete; 25. Anchoring plate; 26. Waste material; 27. Grouting pipe; 28. Curved formwork; 29. ​​Suspension rod; 30. Suspension beam; 31. Casting cavity; 32. Casting port; 33. Drainage pipe; 34. Deformation frame; 35. Hinge shaft; 36. Hanging bar; 37. Hanging ring; 38. Crushed stone layer; 39. Drainage cushion layer; 40. Lightweight concrete; 41. Pavement structure; 42. Top sealing layer. Detailed Implementation

[0034] The following provides a detailed description of the specific implementation methods of the layered waste-filled retaining wall, widened embankment structure system, and construction method described in this invention. Those skilled in the art can understand and implement the technical solution of this invention based on this description, but the scope of protection of this invention is not limited to this specific embodiment.

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. In order to keep the following description of the embodiments of the present invention clear and concise, the detailed description of known functions and known components is omitted.

[0036] Example 1: Layered waste-filled retaining wall structure This embodiment details the specific structural composition of the layered waste filling retaining wall.

[0037] like Figures 1 to 10As shown, the retaining wall structure in this embodiment is installed on the adjacent side of the embankment to be widened, and includes an inner wall panel 6 and an outer wall panel 7. The inner wall panel 6 and the outer wall panel 7 are temporarily fixed together to form a filling cavity, which is used for subsequent layered filling construction.

[0038] Toe beams 8 are provided at the bottom of both the inner wall panel 6 and the outer wall panel 7 to enhance the overall stability of the retaining wall. Before installing the inner wall panel 6 and the outer wall panel 7, a connecting frame 9 is pre-installed in the soil below the toe beam 8, and the connecting frame 9 is further strengthened by pouring a consolidation body 10, thereby forming the bottom anchoring structure of the retaining wall. This bottom anchoring structure can effectively resist the horizontal slippage and overturning of the retaining wall.

[0039] The bottom of the space between the inner wall panel 6 and the outer wall panel 7 is filled with a bottom sealing layer 11, which is formed by pouring concrete and serves to seal the bottom and prevent the filler from leaking out.

[0040] The filling structure between the inner wall panel 6 and the outer wall panel 7 is formed by stacking the lower layer 12, the elliptical tube 13, and the upper covering layer 14 in a sequential and cyclical manner. The shapes of the lower layer 12 and the upper covering layer 14 are adapted to the shape of the elliptical tube 13, specifically, they are arc-shaped or flat-bottomed structures that match the elliptical cross-sectional shape of the elliptical tube 13, to ensure a tight fit between the layers.

[0041] The bottom of the elliptical tube 13 is mounted on a pre-set positioning pin 16 through its own mounting hole. The positioning pin 16 is pre-fixed in the lower layer 12 or the bottom sealing layer 11 to accurately position the installation position of the elliptical tube 13 and prevent the elliptical tube 13 from shifting during the filling construction process.

[0042] The cavity formed by the elliptical tube 13 is filled with a mixed filler 15. The mixed filler 15 is formed by a two-stage filling process: the first filling involves filling the cavity of the elliptical tube 13 with waste material 25, which can be solid waste such as construction waste or industrial slag; the second filling involves installing a grouting pipe 26 at the top of the elliptical tube 13, with the bottom of the grouting pipe 26 extending into the waste material 25, and then injecting fine grout through the grouting pipe 26. The fine grout is cement grout or cement mortar. The fine grout penetrates and fills the pores of the waste material 25, ultimately forming a mixed filler 15 with high consolidation strength and good integrity.

[0043] In this embodiment, a suspended formwork is used to simultaneously pour the upper overlay layer 14 corresponding to the lower elliptical tube 13 and the lower sub-layer 12 corresponding to the upper elliptical tube 13. The suspended formwork includes an arc-shaped formwork 27 adapted to the shape of the elliptical tube 13, which is supported by suspension rods 28 and suspension beams 29. The bottom of the suspension rods 28 abuts against the lower elliptical tube 13, forming a stable support system. The arc-shaped formwork 27 and the lower elliptical tube 13 enclose a pouring cavity 30, and positioning pins 16 for installing the upper elliptical tube 13 are preset in the pouring cavity 30. Concrete is poured through the pouring port 31 opened in the middle of the arc-shaped formwork 27, and the upper overlay layer 14 and the lower sub-layer 12 of the lower elliptical tube 13 are poured in one go, which greatly improves construction efficiency and ensures the quality of interlayer bonding.

[0044] The top of the retaining wall is provided with a top sealing layer 41, which is made of reinforced concrete and seals the uppermost elliptical tube 13 and its overlay layer 14 to form a complete retaining wall structure.

[0045] In this embodiment, the retaining wall structure achieves a reliable connection with the old embankment 1 through the embedding structure 4 and the tie rod 5. One end of the tie rod 5 is connected to the tie node 17 on the inner side of the inner wall panel 6, and the other end of the tie rod 5 is connected to the embedding structure 4. The embedding structure 4 is installed in the embedding groove 3 opened at the step 2 of the old embankment 1. The embedding structure 4 includes an embedding prefabricated component installed in the embedding groove 3. The embedding prefabricated component includes an arched rib 18 and end anchor plates 19 set at both ends of the arched rib 18. The end anchor plates 19 are set in the anchoring end 20, and a connecting plate 21 is provided between two adjacent anchoring ends 20. The embedding prefabricated component is installed as a whole in the embedding groove 3 and is connected to the transition rib 22 through the arched rib 18. The transition rib 22 is connected to the anchoring pressure plate 24 at the top of the embedding groove 3, and the lower part of the anchoring pressure plate 24 is connected to the end of the tie rod 5. After construction in the remaining cavity of the embedding groove 3, anchoring concrete 23 is poured to complete the installation and fixation of the embedding structure 4, forming a strong pull-out anchoring system.

[0046] Example 2: Widened Embankment Structure and its Connection System with Retaining Wall This embodiment details the specific structural components of the widened embankment and its collaborative working relationship with the retaining wall.

[0047] like Figure 1 , Figure 2 as well as Figures 9-11 As shown, the widened embankment in this embodiment includes a gravel soil layer 37, a drainage cushion layer 38, a lightweight concrete layer 39, and a pavement structure 40, which are constructed sequentially within the area enclosed by the steps 2 of the old embankment 1 and the adjacent side retaining wall.

[0048] The crushed stone layer 37 is laid at the bottom of the area between the steps 2 and the inner wall panel 6 of the old embankment 1. It uses graded crushed stone material and is laid and compacted in layers during the laying process. The compaction degree is not less than 95%, forming a solid working foundation.

[0049] A drainage cushion layer 38 is constructed on top of the crushed stone layer 37. The drainage cushion layer 38 is made of highly permeable gravel material and has a thickness of 20cm to 30cm. A drainage pipe 32 is installed inside the drainage cushion layer 38. The drainage pipe 32 is made of HDPE double-wall corrugated pipe or PVC pipe. The installation position and slope of the drainage pipe 32 are strictly implemented according to the design requirements, with a slope of not less than 1%, to ensure that water accumulated inside the road structure can be drained in a timely manner.

[0050] To prevent displacement of the drainage pipe 32 during construction, the drainage pipe 32 is temporarily and elastically fixed to the tie rod 5. Specifically, a lifting ring 36 and a lifting rod 35 are installed on the tie rod 5. The bottom of the lifting rod 35 is connected to a deformable frame 33, which is connected to the drainage pipe 32. The deformable frame 33 is composed of multiple support rods connected by a hinge shaft 34, forming a deformable frame structure. The movement of the support rods relative to the hinge shaft 34 allows the deformable frame 33 to change shape within a certain range during embankment filling when subjected to external loads. This avoids rigidly binding the drainage pipe 32 and causing damage, while also providing a limiting function within a certain range to prevent excessive displacement of the drainage pipe 32 and ensure the normal operation of the drainage system.

[0051] After the drainage cushion layer 38 and drainage pipe 32 are completed and accepted, lightweight concrete 39 is constructed on top of the drainage cushion layer 38. The lightweight concrete 39 is made of foamed concrete or lightweight aggregate concrete. During the pouring of the lightweight concrete 39, it is vibrated and compacted in layers, with each layer not exceeding 30cm in thickness, in order to reduce the self-weight of the embankment and reduce the additional load on the old embankment 1 and retaining wall.

[0052] After the lightweight concrete 39 reaches its design strength, the pavement structure 40 is constructed on top of the lightweight concrete 39. The pavement structure 40 includes the base course and surface course, and the specific structural combination is determined according to the road grade design requirements to form a complete road function.

[0053] In this embodiment, the widened embankment structure provides foundation support through the crushed stone soil layer 37, achieves internal drainage through the drainage cushion layer 38 and drainage pipe 32, and reduces its self-weight through lightweight concrete 39, ultimately forming a stable, lightweight, and well-drained widened embankment structure system. It works in conjunction with the adjacent side retaining wall to jointly ensure the overall stability and service life of the road after widening.

[0054] Example 3: Construction Method of Layered Waste-Infill Retaining Wall and Widened Embankment Structure System This embodiment details the specific construction steps of the layered waste-filled retaining wall and widened embankment structure system.

[0055] Step 1: Construction of old embankment treatment and embedment structure S11. Excavation of existing embankment steps and embedment trenches: Excavate steps on existing embankment 1 to form step 2. Step 2 has a width of not less than 1.0m and a height of not more than 1.0m. Step 2 slopes outward with a gradient of 2% to 4% to facilitate drainage. Embedment trenches 3 are formed within step 2 through excavation. Embedment trenches 3 have a depth of not less than 0.5m, and their width is determined according to the dimensions of the embedded precast components.

[0056] S12. Installation and fixing of precast components and tie bars: The precast components are installed in the embedding groove 3. The precast components include arched ribs 18 and end anchor plates 19 at both ends of the arched ribs 18. The end anchor plates 19 are located in the anchoring ends 20, and a connecting plate 21 is provided between two adjacent anchoring ends 20. Then, the arched ribs 18 are connected and fixed to the transition ribs 22. The other end of the transition ribs 22 is connected to the anchoring pressure plate 24 at the top of the embedding groove 3. At the same time, the end of the tie bar 5 is connected and fixed to the lower part of the anchoring pressure plate 24. The tie bars 5 are made of high-strength steel strand or precision-rolled threaded steel, and the quantity is determined according to the design tension calculation.

[0057] S13. Post-cast anchor concrete construction: Post-cast anchor concrete 23 is constructed in the remaining cavity of the embedding groove 3. The post-cast anchor concrete 23 is made of micro-expansion concrete with a strength grade of not less than C30. It is fully vibrated and compacted during pouring to ensure a tight bond with the precast embedding component and the soil of the old embankment 1, thereby completing the installation and fixing of the embedding structure 4 and forming the embedding structure 4.

[0058] Step 2: Anchoring structure at the bottom of the retaining wall and installation of the wall body S21. Construction of the bottom anchoring structure: Before installing the inner wall panel 6 and the outer wall panel 7, a connecting frame 9 is set in the soil below the pre-set wall toe beam 8. The connecting frame 9 is a rectangular frame welded with steel bars, and the depth of embedment in the soil is not less than 0.5m. The connecting frame 9 is further strengthened by pouring the solidification body 10, which is formed by grouting with cement grout or cement mortar, thus forming the bottom anchoring structure of the retaining wall.

[0059] S22. Construction of Toe Beams, Inner and Outer Wall Panels, and Bottom Sealing Layer: Toe beams 8 are installed at the bottom of both the inner wall panel 6 and the outer wall panel 7. The toe beams 8 are made of reinforced concrete, and their cross-sectional dimensions are determined based on the height of the retaining wall. The inner wall panel 6 and the outer wall panel 7 are temporarily fixed together by opposing tie rods to form a filled cavity. The temporary tie rods use adjustable-length steel supports or turnbuckles. A bottom sealing layer 11 is filled at the bottom between the inner wall panel 6 and the outer wall panel 7. The bottom sealing layer 11 is made of C20 concrete and has a thickness of not less than 15cm.

[0060] Step 3: Cyclic construction of the elliptical tube filling structure S31. Bottom Structure Construction: First, construct the bottommost lower layer 12 and the elliptical tube 13. The lower layer 12 is leveled with fine aggregate concrete, with a thickness of 5cm~8cm. The first elliptical tube 13 is installed before initial setting.

[0061] S32. Installation of Suspended Formwork and Formation of Pouring Cavity: Install suspended formwork, which includes an arc-shaped formwork 27 adapted to the shape of the elliptical tube 13. The arc-shaped formwork 27 is made of steel plate or high-strength plastic formwork. The arc-shaped formwork 27 is supported by suspension rods 28 and suspension beams 29. The suspension rods 28 are adjustable-length threaded rods, and the suspension beams 29 are made of I-beams or channel steel. The bottom of the suspension rods 28 abuts against the lower-level installed elliptical tube 13, and the arc-shaped formwork 27 and the lower-level installed elliptical tube 13 enclose and form the pouring cavity 30.

[0062] S33. Positioning Pin Pre-setting and Concrete Pouring: Positioning pins 16 for installing the upper elliptical tube 13 are pre-set in the pouring cavity 30. The positioning pins 16 are made of steel bars or steel pipes, with a length of not less than 15cm, and are vertically fixed to the bottom of the pouring cavity 30. Concrete is poured through the pouring port 31 opened in the middle of the arc-shaped template 27. The diameter of the pouring port 31 is not less than 15cm. The upper overlay layer 14 of the lower elliptical tube 13 and the lower underlay layer 12 of the upper elliptical tube 13 are poured in one go. C25 fine aggregate concrete is used.

[0063] S34. Elliptical Tube Installation and Two-Stage Filling: After the concrete has initially set, the bottom of the elliptical tube 13 is installed onto the pre-set positioning pin 16 through its own installation hole. Waste material 25 is then filled into the cavity formed by the elliptical tube 13 to complete the first filling. A grouting pipe 26 is installed at the top of the elliptical tube 13, with its bottom extending into the waste material 25. The grouting pipe 26 is made of PVC or steel and has a diameter of not less than 25mm. Fine grout is injected through the grouting pipe 26 to penetrate and fill the pores of the waste material 25. The water-cement ratio of the fine grout is 0.4~0.5, and the grouting pressure is 0.2MPa~0.5MPa, ultimately forming a mixed filler 15.

[0064] S35. Cyclic Layer-by-Layer Construction: The lower layer 12, elliptical tube 13 and upper covering layer 14 are constructed in a cyclical manner, stacking layer by layer to form the filling structure between the inner wall panel 6 and the outer wall panel 7. The height of each layer is determined according to the height of the elliptical tube 13, generally 30cm~80cm.

[0065] S36. Top sealing of retaining wall: Construct a top sealing layer 41 at the top of the retaining wall. The top sealing layer is made of reinforced concrete with a thickness of not less than 15cm and a concrete strength grade of not less than C25, and seals the uppermost elliptical tube 13.

[0066] Step 4: Final Fixing of Tie Bars One end of the tie bar 5 is connected to the tie node 17 on the inner side of the inner wall panel 6. The tie node 17 is in the form of a pre-embedded steel plate or an anchor. The other end of the tie bar 5 is connected to the lower part of the anchor plate 24. After adjusting the tension of the tie bar 5 to the design value, it is locked, thus completing the construction of the embedded structure 4 connected to the retaining wall through the tie bar 5.

[0067] Step 5: Construction of widened embankment Within the area enclosed by step 2 of the old embankment 1 and the adjacent retaining wall, the widened embankment will be constructed sequentially. The specific construction process is as follows: S51. Construction of Crushed Stone Soil Layer, Drainage Subbase, and Drainage Pipes: First, a crushed stone soil layer 37 is laid within the enclosed area. The crushed stone soil layer 37 uses graded crushed stone. During the laying process, the crushed stone soil layer 37 is spread and compacted in layers, with each layer having a loose thickness of no more than 30cm and a compaction degree of no less than 95%. A drainage subbase 38 is constructed on top of the crushed stone soil layer 37. The drainage subbase 38 uses medium-coarse sand or gravel, with a thickness of 20cm to 30cm. Simultaneously, drainage pipes 32 are installed within the drainage subbase 38. The installation position and slope of the drainage pipes 32 strictly adhere to the design requirements, with a slope of no less than 1%.

[0068] To prevent displacement of the drainage pipe 32 during construction, the drainage pipe 32 is temporarily and elastically fixed to the tie rod 5. Specifically, this is achieved by installing lifting rings 36 and lifting rods 35 on the tie rod 5. The lifting rings 36 are U-shaped steel bars or special lifting rings, and the lifting rods 35 are steel bars or steel strands. The bottom of the lifting rods 35 is connected to the deformable frame 33, which is in turn connected to the drainage pipe 32. The deformable frame 33 is assembled from multiple support rods connected by a hinge shaft 34. The support rods are made of steel bars or flat steel, and the hinge shaft 34 uses bolts or pins. The movement of the support rods relative to the hinge shaft 34 allows the deformable frame 33 to change shape within a certain range under external loads during embankment filling. This avoids rigidly binding the drainage pipe 32 and simultaneously provides a limiting function for the drainage pipe 32 within a certain range, preventing excessive displacement.

[0069] S52. Lightweight Concrete Construction: After the drainage cushion layer 38 and drainage pipe 32 are completed and accepted, lightweight concrete 39 is constructed on top of the drainage cushion layer 38. When foamed concrete is used for lightweight concrete 39, the wet density is controlled at 800 kg / m³. 3 ~1000kg / m 3 When using lightweight aggregate concrete, the dry density should be controlled at 1000 kg / m³. 3 ~1200kg / m 3 Lightweight concrete 39 should be compacted in layers during pouring, with each layer not exceeding 30cm in thickness. After pouring, it should be covered and cured promptly.

[0070] S53. Road Structure Construction: After the lightweight concrete 39 reaches its design strength, generally more than 80% of its 28-day strength, the road structure 40 is constructed on top of the lightweight concrete 39. The road structure 40 is determined according to the road grade and generally includes a cement-stabilized crushed stone base course, an asphalt concrete surface course, or a cement concrete surface course. It is constructed in layers according to the corresponding construction specifications to form a complete road surface.

[0071] Through the above construction steps, the construction of the layered waste-filled retaining wall and widened embankment structure system is completed, forming an embankment widening project that is safe to construct, structurally stable, utilizes waste, and can be quickly completed.

Claims

1. A layered waste-filled retaining wall and widened embankment structural system, characterized in that, Includes steps (2) opened on the old embankment (1), wherein the steps (2) are provided with a retaining structure (4) by means of a retaining groove (3) formed by excavation; the retaining structure (4) is connected to the retaining wall by means of a tie rod (5); The retaining wall is set on the edge of the embankment to be widened, including an inner wall panel (6) and an outer wall panel (7); the inner wall panel (6) and the outer wall panel (7) are temporarily fixed by opposite tie to form a filling cavity; a wall toe beam (8) is set at the bottom of both the inner wall panel (6) and the outer wall panel (7); before installing the inner wall panel (6) and the outer wall panel (7), a connecting frame (9) is set in the soil under the preset wall toe beam (8), and the connecting frame (9) is further strengthened by pouring a consolidation body (10) to form the bottom anchoring structure of the retaining wall; the bottom end between the inner wall panel (6) and the outer wall panel (7) is filled with a bottom sealing layer (11). The filling structure between the inner wall panel (6) and the outer wall panel (7) is formed by stacking the lower layer (12), the elliptical tube (13) and the upper covering layer (14) in a sequential and cyclical manner; the shapes of the lower layer (12) and the upper covering layer (14) are adapted to the shape of the elliptical tube (13); the bottom of the elliptical tube (13) is installed on the preset positioning pin (16) through the installation hole opened by itself. The cavity enclosed by the elliptical tube (13) is filled with a mixed filler (15). The mixed filler (15) is formed by a two-stage filling process: the first filling is to fill the cavity of the elliptical tube (13) with waste material (25), and the second filling is to install a grouting pipe (26) at the top of the elliptical tube (13), so that the bottom of the grouting pipe (26) extends into the waste material (25), and then inject fine grout through the grouting pipe (26). The fine grout penetrates and fills the pores of the waste material (25), and finally forms the mixed filler (15). A suspended formwork is used to simultaneously cast the upper overlay (14) corresponding to the lower elliptical tube (13) and the lower sub-layer (12) corresponding to the pre-installed position of the upper elliptical tube (13); the suspended formwork includes an arc-shaped formwork (27) adapted to the shape of the elliptical tube (13), and the arc-shaped formwork (27) is supported by a suspension rod (28) and a suspension beam (29); the bottom of the suspension rod (28) abuts against the lower elliptical tube (13) that has already been installed; the arc-shaped formwork (27) is supported by a suspension rod (28) and a suspension beam (29). The curved template (27) and the lower installed elliptical tube (13) enclose to form a pouring cavity (30), and a positioning pin (16) for the installation of the upper elliptical tube (13) is preset in the pouring cavity (30); concrete is poured through the pouring port (31) opened in the middle of the curved template (27), and the upper cover layer (14) of the lower elliptical tube (13) and the lower back layer (12) of the upper elliptical tube (13) are poured in one go; the top of the retaining wall is provided with a top sealing layer (41).

2. The layered waste-filled retaining wall and widened embankment structure system according to claim 1, characterized in that, The embedment structure (4) is connected to the retaining wall by a tie rod (5). Specifically, one end of the tie rod (5) is connected to the tie node (17) on the inner side of the inner wall panel (6), and the other end of the tie rod (5) is connected to the embedment structure (4). The embedment structure (4) is installed in the embedment groove (3) opened at the step (2). The embedment structure (4) includes an embedment prefabricated component installed in the embedment groove (3). The embedment prefabricated component includes an arched rib (18) and end anchor plates (19) set at both ends of the arched rib (18). Plate (19) is set in the anchor end (20), and a connecting plate (21) is provided between two adjacent anchor ends (20); the embedded prefabricated component is installed in the embedded groove (3) as a whole, and is connected to the transition bar (22) through the arch bar (18). The transition bar (22) is connected to the anchor pressure plate (24) at the top of the embedded groove (3). The lower part of the anchor pressure plate (24) is connected to the end of the tie bar (5); after construction in the remaining cavity of the embedded groove (3), the anchor concrete (23) is poured to complete the installation and fixing of the embedded structure (4).

3. The layered waste-filled retaining wall and widened embankment structure system according to claim 1, characterized in that, The widened embankment includes a gravel soil layer (37), a drainage cushion layer (38), a lightweight concrete layer (39), and a pavement structure (40) constructed sequentially within the area enclosed by the steps (2) of the old embankment (1) and the adjacent side retaining wall; wherein a drainage pipe (32) is installed in the drainage cushion layer (38).

4. The layered waste-filled retaining wall and widened embankment structure system according to claim 3, characterized in that, To prevent the drainage pipe (32) from shifting during construction, the drainage pipe (32) and the tie bar (5) are temporarily and elastically fixed. Specifically, the tie bar (5) is equipped with a lifting ring (36) and a lifting bar (35). The bottom of the lifting bar (35) is connected to the deformation frame (33), and the deformation frame (33) is connected to the drainage pipe (32). The deformation frame (33) is assembled by connecting multiple support rods through a hinge shaft (34). Through the movement of the support rods relative to the hinge shaft (34), the deformation frame (33) can change shape within a certain range when subjected to external loads during the embankment filling process, thereby avoiding rigid connection of the drainage pipe (32) and at the same time, it plays a role in connecting and limiting the drainage pipe (32) within a certain range, preventing excessive displacement of the drainage pipe (32).

5. A construction method for a layered waste-filled retaining wall and widened embankment structure system, characterized in that, Includes the following steps: Step 1: Construction of old embankment treatment and embedment structure S11. Excavation of old embankment steps and embedment trenches: Steps are excavated on the old embankment (1) to form steps (2), and embedment trenches (3) are formed in the steps (2) through excavation. S12, Install and fix the precast component and tie rod: Install the precast component in the embedding groove (3); then connect and fix the arched bar (18) and the transition bar (22), connect the other end of the transition bar (22) to the anchor plate (24) at the top of the embedding groove (3), and connect and fix the end of the tie rod (5) to the lower part of the anchor plate (24); S13. Post-cast anchor concrete construction: Post-cast anchor concrete (23) is constructed in the remaining cavity of the embedding groove (3) to complete the installation and fixation of the embedding structure (4) and form the embedding structure (4). Step 2: Anchoring structure at the bottom of the retaining wall and installation of the wall body S21. Construction of bottom anchoring structure: Before installing the inner wall panel (6) and the outer wall panel (7), a connecting frame (9) is set in the soil under the pre-set wall toe beam (8). The connecting frame (9) is further strengthened by pouring the solidified body (10) to form the bottom anchoring structure of the retaining wall. S22. Construction of wall toe beam, inner and outer wall panels and bottom sealing layer: Wall toe beam (8) is set at the bottom of both inner wall panel (6) and outer wall panel (7). The inner wall panel (6) and outer wall panel (7) are fixed by opposite temporary tie to form a filling cavity. The bottom sealing layer (11) is filled between the inner wall panel (6) and outer wall panel (7). Step 3: Cyclic construction of the elliptical tube filling structure S31. Bottom structure construction: First, construct the bottommost subfloor (12) and elliptical tube (13). S32, Installation of suspended formwork and formation of pouring cavity: Install suspended formwork, which includes an arc-shaped formwork (27) that is adapted to the shape of the elliptical tube (13). The arc-shaped formwork (27) is supported by a suspension rod (28) and a suspension beam (29). The bottom of the suspension rod (28) abuts against the lower installed elliptical tube (13). The arc-shaped formwork (27) and the lower installed elliptical tube (13) enclose each other to form a pouring cavity (30). S33, Positioning pin pre-setting and concrete pouring: Positioning pins (16) for the installation of the upper elliptical tube (13) are pre-set in the pouring cavity (30), and concrete is poured through the pouring port (31) opened in the middle of the arc template (27) to complete the upper cover layer (14) of the lower elliptical tube (13) and the lower cover layer (12) of the upper elliptical tube (13) in one go. S34. Elliptical tube installation and two-stage filling: The bottom of the elliptical tube (13) is installed on the preset positioning pin (16) through its own installation hole. Waste material (25) is filled into the cavity formed by the elliptical tube (13) to complete the first filling. A grouting pipe (26) is set at the top of the elliptical tube (13) so that the bottom of the grouting pipe (26) extends into the waste material (25). Fine grout is injected through the grouting pipe (26) so that the fine grout penetrates and fills the pores of the waste material (25) to finally form a mixed filler (15). S35. Cyclic layer-by-layer construction: The lower layer (12), elliptical tube (13) and upper overlay layer (14) are constructed in a cyclical manner, stacking layer by layer to form the filling structure between the inner wall panel (6) and the outer wall panel (7); S36. Top sealing of retaining wall: Construct a top sealing layer (41) at the top of the retaining wall. Step 4: Final Fixing of Tie Bars One end of the tie bar (5) is connected to the tie node (17) on the inner side of the inner wall panel (6), and the other end of the tie bar (5) is connected to the lower part of the anchor plate (24) to complete the construction of the embedded structure (4) connected to the retaining wall through the tie bar (5); Step 5: Construction of widened embankment Within the area enclosed by the steps (2) of the old embankment (1) and the adjacent retaining wall, the widened embankment is constructed sequentially. The specific construction process is as follows: S51. Construction of the gravel soil layer, drainage cushion layer, and drainage pipe: First, a gravel soil layer (37) is laid in the enclosed area. During the laying of the gravel soil layer (37), it is spread and compacted in layers. A drainage cushion layer (38) is constructed on top of the gravel soil layer (37), and a drainage pipe (32) is installed in the drainage cushion layer (38). The installation position and slope of the drainage pipe (32) are strictly in accordance with the design requirements. In order to avoid the drainage pipe (32) from shifting during construction, the drainage pipe (32) is temporarily and elastically fixed to the tie bar (5). The specific setting method is: by installing a lifting ring (3) on the tie bar (5). 6) Connect the bottom of the suspension rod (35) to the deformation frame (33), and connect the deformation frame (33) to the drainage pipe (32). The deformation frame (33) is assembled by connecting multiple support rods through the hinge shaft (34). Through the movement of the support rods relative to the hinge shaft (34), the deformation frame (33) can change shape within a certain range when subjected to external loads during the embankment filling process, thereby avoiding rigid connection of the drainage pipe (32) and at the same time playing a connection and limiting role for the drainage pipe (32) within a certain range, preventing excessive displacement of the drainage pipe (32). S52, Lightweight concrete construction: After the drainage cushion (38) and drainage pipe (32) are completed and accepted, lightweight concrete (39) is constructed on top of the drainage cushion (38). The lightweight concrete (39) is compacted in layers during the pouring process. S53. Road structure construction: After the lightweight concrete (39) reaches the design strength, the road structure (40) is constructed on top of the lightweight concrete (39).

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