Debris flow retaining dam with self-returning pavement structure and construction method

Abstract

The debris flow barrier dam with a self-returning pavement structure and the construction method belong to the field of debris flow disaster prevention and control. The debris flow barrier dam structure with a self-returning pavement structure includes an arch barrier dam 1, an airbag buffer structure 2, a fixed support pile 3, a sliding support pile 4 and an arch-hole pavement structure 5; the arch barrier dam 1 is composed of a box structure 6, a crushed stone filling 7, a culvert 8 and a seepage ditch 9; the airbag buffer structure 2 is composed of a casing 26 and an airbag 27; the sliding support pile 4 is composed of a ball-type sliding bearing 28, a rectangular pile 29 and a slot 30; the arch-hole pavement 5 is composed of a self-returning pavement 36 and an arch-hole structure 37; the invention has a simple structure, strong practicality, safety and reliability, and can be applied to mountainous areas along roads prone to debris flow, solving the problem that the barrier dam has insufficient blocking capacity in debris flow-prone areas, and the road is damaged by the impact of debris flow and rolling stones, thereby affecting traffic safety.

Description

Technical Field

[0001] This invention belongs to the field of debris flow disaster prevention and control, specifically involving debris flow retaining dams with self-returning pavement structures and construction technology, and is applicable to debris flow protection and control projects. Background Technology

[0002] In the field of debris flow prevention and control, retaining dams are one of the most commonly used engineering measures to reduce the impact and erosion damage of debris flows on buildings by controlling the solid materials in the debris flow and reducing the flow rate. After years of development, retaining dam technology still has many shortcomings. How to reduce the damage of debris flows to the dam body while ensuring safe passage (including for pedestrians and vehicles) and improving space utilization is extremely important. Existing debris flow retaining dam technologies cannot effectively solve this problem; they can only impound debris flows and reduce their scale. For large and frequent debris flows, dam failure is still likely, and road traffic safety cannot be guaranteed. For example, the gabion arch ecological flexible debris flow retaining dam and its construction method (patent number CN104164851A) provides a gabion transverse arch ecological flexible debris flow retaining dam that solves the problems of impounding colluvial deposits in the source area of ​​small-scale debris flows and impounding debris flows in the flow area. However, its drawbacks are as follows: Firstly, limited by the structure and materials themselves, it cannot withstand large-scale and frequent debris flow impacts, and it lacks the function and conditions for safe passage at the top. Secondly, the structure consists of two parts: energy-dissipating piers and gabion arch dams. Both parts work together to achieve the barrier effect, which results in insufficient space utilization. The separation of the two functions may also lead to damage to the front energy-dissipating piers, increasing the difficulty of subsequent dredging. Moreover, the transverse arch is prone to causing landslides on the slopes at the support points at both ends of the arch. Patent number CN108867569A describes a naturally dredging debris flow barrier dam and its application, providing a debris flow barrier dam capable of natural dredging. This solves the problem of dredging work and sediment disposal in the reservoir area after the barrier project is full. However, its drawbacks are as follows: Firstly, the construction process is complex and not suitable for construction, and the dredging effect is not obvious. Secondly, when the road encounters a debris flow, safe passage cannot be guaranteed. Therefore, it is necessary to propose a debris flow barrier that can both mitigate the impact of debris flows at the bottom and allow normal traffic flow at the top, for the prevention and control of debris flows along roads. Summary of the Invention

[0003] The purpose of this invention is to provide a debris flow retaining dam with a self-returning pavement structure and a construction method thereof.

[0004] This invention relates to a debris flow retaining dam with a self-returning pavement structure and its construction method. The debris flow retaining dam with a self-returning pavement structure includes an arched retaining dam 1, an air-bag buffer structure 2, fixed support piles 3, sliding support piles 4, and an arched pavement structure 5. The arched retaining dam 1 consists of a box-shaped structure 6, crushed stone filling material 7, culverts 8, and seepage trenches 9. The box-shaped structure 6 consists of a retaining shell 10 and a foundation shell 11. The retaining shell 10 is a hollow box-shaped structure with an open bottom, which consists of an arched wall panel 12, a buttress-type retaining wall panel 13, and a rectangular top cover 14. The arched wall panel 12 is a wall panel with an arched cross-section perpendicular to the ground. Its surface is provided with circular drainage holes 15 arranged in a quincunx pattern. Culverts are spaced apart at the bottom of the wall. The rectangular holes 16 are arranged in a staggered pattern, with the normal direction of the wall surface aligned with the debris flow impact direction. The buttress-type retaining wall panel 13 is a typical buttress-type retaining wall, with drainage holes 15 arranged in a staggered pattern on its wall surface. Culvert-type rectangular holes 16 are spaced apart at the bottom of the wall surface, and seepage trench-type rectangular holes 17 are arranged in a staggered pattern in the middle of the wall surface, with the normal direction of the wall surface aligned with the debris flow impact direction. The rectangular top cover 14 is a thin plate with a rectangular cross-section, parallel to the ground, and with its long side parallel to the upstream and downstream sides of the retaining dam. Rectangular holes 18 are spaced apart near the edges of the upstream and downstream sides of the top cover. The top of the arched wall panel 12 and the top of the buttress-type retaining wall panel 13 are directly connected to the bottom edge of the long side of the horizontally arranged rectangular top cover 14 to jointly form the retaining shell 10. Plate 12 is the wall panel on the upstream side of the retaining shell 10, and the buttress-type retaining wall panel 13 is the wall panel on the downstream side of the retaining shell 10. The top surface of the retaining shell 10 is a rectangular top cover 14. The foundation shell 11 is a rectangular hollow box-shaped structure with a partially open top surface, which is composed of a first type of rectangular plate 19a, a second type of rectangular plate 19b, and a third type of rectangular plate 19c. The first type of rectangular plate 19a is a common rectangular wall panel perpendicular to the horizontal plane, and the normal direction of its wall surface is the direction of debris flow impact. The second type of rectangular plate 19b is a rectangular thin plate parallel to the horizontal plane and with its long side parallel to the upstream and downstream sides of the retaining dam. Its surface is provided with bottom rectangular holes 18 at intervals near the upstream and downstream sides. The third type of rectangular plate 19c is parallel to the horizontal plane. The rectangular thin plates, with their long sides parallel to the upstream and downstream surfaces of the dam, have dimensions smaller than the second type of rectangular plate 19b along the debris flow impact direction. The first type of rectangular plates 19a form the upstream and downstream walls of the foundation shell 11, respectively. The bottoms of the two first type of rectangular plates 19a are connected to the long edge of the top surface of the second type of rectangular plate 19b, respectively. The upstream long edge of the bottom surface of the third type of rectangular plate 19c is connected to the top of the upstream first type of rectangular plate 19a, thus forming the foundation shell 11. The dam shell 10 is located above ground, while the foundation shell 11 is buried below ground. The bottom of the arched wall panel 12 of the dam shell 10 is connected to the downstream long edge of the top surface of the third type of rectangular plate 19c of the foundation shell 11.The bottom of the buttress-type retaining wall panel 13 of the retaining shell 10 is directly connected to the top of the first type rectangular plate 19a on the backflow side of the foundation shell 11. The rectangular hole 18 at the top of the retaining shell 10 and the rectangular hole 18 at the bottom of the foundation shell 11 completely overlap from a top-view angle. The crushed stone filler 7 is composed of locally sourced crushed stone and soil. The culvert 8 is a conventional water pipe with a rectangular cross-section. The seepage ditch 9 is a water pipe with a rectangular cross-section, which is composed of a first type plate 20a, a second type plate 20b, and a filter layer 21. Plate 20a is a thin plate with a rectangular cross-section. Permeable holes 22 are spaced at intervals along the direction perpendicular to the pipe cross-section of plate 20a. Plate 20b is a common thin plate with a rectangular cross-section parallel to the horizontal plane. The filter layer 21 is a thin layer with a rectangular cross-section and a certain thickness, composed of layers of medium sand, coarse sand, and gravel. Plates 20a are the top and side plates of the seepage trench 9, respectively. Plate 20b is the bottom plate of the seepage trench 9. The bottom surface of the top plate and the top surface of the bottom plate are located on the left and right sides along the long side. The edges are connected to the top and bottom of the side plate along the long side, respectively. The upper surface of the filter layer 21 is bonded to the bottom surface of the top plate and the inner side of the side plate, respectively, thus forming the seepage trench 9. The box-shaped structure 6 is filled with crushed stone filler 7, and vertical rectangular channels 23 perpendicular to the ground are reserved at the positions corresponding to the rectangular holes 18. Horizontal rectangular channels 24 perpendicular to the upstream face of the dam are reserved at the positions corresponding to the culvert-type rectangular holes 16. Vertical channels 24 perpendicular to the upstream face of the dam are reserved at the positions corresponding to the seepage trench-type rectangular holes 17. The permeable duct 25 is a transverse rectangular channel of seepage groove. The culvert 8 has its pipe axis perpendicular to the flow-facing surface of the retaining shell 10 and passes sequentially through the culvert-type rectangular hole 16 of the arched wall panel 12, the culvert-type transverse rectangular channel 24 of the crushed stone filling 7, and the culvert-type rectangular hole 16 of the buttress-type retaining wall panel 13. The permeable duct 9 has its pipe axis perpendicular to the flow-facing surface of the retaining shell 10 and passes sequentially through the permeable duct-type transverse rectangular channel 25 of the crushed stone filling 7 and the permeable duct-type rectangular hole 17 of the buttress-type retaining wall panel 13.

[0005] The airbag buffer structure 2 consists of a sleeve 26 and an airbag 27. The sleeve 26 is a rectangular hollow steel sleeve, and the airbag 27 is a cylindrical rubber inflatable structure with a rectangular ring cross-section. The cylindrical outer wall of the airbag 27 is connected to the inner wall of the sleeve 26, thus forming the airbag buffer structure 2 together.

[0006] Fixed support pile 3 is an ordinary pile with a rectangular cross-section.

[0007] The sliding support pile 4 consists of a ball-type sliding bearing 28, a rectangular pile 29, and a groove 30. The ball-type sliding bearing 28 consists of a base 31, steel balls 32, and a thin steel plate 33. The base 31 is a thin plate with a rectangular cross-section. A groove 34 is provided on the top surface of the base 31 along the direction of debris flow impact. The steel balls 32 are steel balls with rotating shafts. The thin steel plate 33 is an ultra-thin steel plate with a rectangular cross-section. A row of steel balls 32 is placed inside each groove 34 of the base 31. The centroid height of the steel balls 32 is lower than the top surface of the base 31. The sides of the base 31 are wrapped with... A thin steel plate 33 is formed around the rectangular pile 29, which is a pile with a rectangular cross-section. The slot 30 is formed by vertically arranged I-beam embedded parts 35, which are in the shape of a rectangular ring. One side of the flange of the I-beam embedded part 35 faces the inside of the ring. A part of the body of the I-beam embedded part 35 in the slot 30 is embedded in the top of the rectangular pile 29. The ball bearing sliding support 28 is installed in the slot 30 at the top of the rectangular pile 29. The thin steel plate 33 of the ball bearing sliding support 28 is welded together with the flange of the I-beam embedded part 35 in the slot 30 to form a sliding support pile 4.

[0008] The arch-type pavement structure 5 consists of a self-returning pavement 36 and an arch structure 37. The self-returning pavement 36 consists of a pavement panel 38 and a self-returning structure 39. The pavement panel 38 is a rectangular slab cast on-site. The self-returning structure 39 consists of a limiter 40 and a return spring 41. The limiter 40 consists of two pairs of L-shaped steel plates, which are inverted and symmetrically arranged along the direction of debris flow impact. The return spring 41 consists of two pairs of helical springs, symmetrically arranged. One end of each return spring 41 is fixed to the long side steel plate of the L-shaped plate at the end of the limiter 40, and the other end is left unattended, thus forming the self-returning structure 39. The limiter 40 of the structure 39 is fixed to the edge of the bottom surface of the road panel 38 near the back flow side by bolts, thus forming the self-returning road surface 36. The arch structure 37 consists of a framed arch 42 and a rolling stone protection net 43. The framed arch 42 is an arched open opening. A row of rectangular frames 44 is set at intervals on the arch on the front flow side. The rolling stone protection net 43 is composed of high-strength iron wires. The rolling stone protection net 43 is installed on the rectangular frames 44 of the framed arch 42. The arch toes on both sides of the arch structure 37 are directly connected to the front and back flow sides of the top surface of the road panel 38 of the self-returning road surface 36, and are cast in one piece on site.

[0009] The sleeve 26 of the airbag buffer structure 2 is inserted into the reserved vertical rectangular channel 23 of the arched retaining dam 1. The fixed support pile 3 is inserted into the central rectangular ring of the airbag 27 of the airbag buffer structure 2 near the upstream side. The pile body of the fixed support pile 3 passes through the arched retaining dam 1 and is supported in the bedrock at the bottom of the arched retaining dam 1. The rectangular pile 29 of the sliding support pile 4 is inserted into the central rectangular ring of the airbag 27 of the airbag buffer structure 2 near the downstream side. The rectangular pile 29 of the sliding support pile 4 passes through the arched retaining dam 1 and is supported in the bedrock at the bottom of the arched retaining dam 1. In the arch-shaped pavement structure 5, the bottom surface of the pavement panel 38 near the edge of the upstream side is connected to the top surface of the fixed support pile 3 and is cast integrally. The bottom surface of the pavement panel 38 near the edge of the downstream side is connected to the top surface of the ball-type sliding support 28 at the top of the sliding support pile 4. The connection method is a sliding connection. The empty end of the return spring 41 of the arch-shaped pavement structure 5 is connected to the top of both sides of the sliding support pile 4 along the debris flow impact direction. The axis of symmetry of the limiter 40 of the arch-shaped pavement structure 5 coincides with the center of the cross section of the sliding support pile 4.

[0010] The construction method of the debris flow retaining dam with self-returning pavement structure of the present invention includes the following steps: Step (1) Survey and design: Survey the engineering geological conditions of the road and the mountain on the side of the road, the hydrological and meteorological conditions, determine the impact direction of the debris flow and predict the maximum impact load, perform calculation and design, and determine the height of the pile, the cross-sectional dimensions of the pile body and the pile spacing.

[0011] Step (2) Prefabricate ball bearing sliding support 28: Prefabricate according to the design dimensions in advance and transport to the site for storage; Step (3) Construction of box structure 6: Excavate the soil to the design elevation of the bottom of the arched retaining dam 1, pour the bottom slab and side walls, and reserve the position corresponding to the bottom rectangular hole 18 when pouring the bottom slab, and reserve the corresponding positions of the drainage hole 15, culvert 8 and seepage ditch 9 on the side walls;

[0012] Step (4) Drilling and molding: The lower piles of the arched retaining dam 1 are cast by drilling, and the upper piles are cast by molding. Drill holes along the pre-reserved pile holes in the bottom plate, mold the upper part, and install the sleeve 26.

[0013] Step (5) Backfilling: Fill the box-shaped structure 6 with crushed stone filler 7 in layers according to the design requirements. During the backfilling process, culverts 8 and seepage ditches 9 should be poured in the corresponding positions in a timely manner.

[0014] Step (6) Construction of sliding support pile 4: hoist and place the steel cage, pour the sliding support pile, set the I-beam embedded part 35 at the pile top position as required, and hoist and weld the ball-type sliding support 28.

[0015] Step (7) Road panel 38 Formwork: Form the mold according to the design requirements and set the panel reinforcement;

[0016] Step (8) Construction of fixed support pile 3 and road slab 38: hoist and place the steel cage, and pour the fixed support pile 3 and road slab 38 as a whole;

[0017] Step (9) Pile body formwork removal: After the curing is completed, the pile body formwork is removed and the airbag 27 structure that meets the design requirements is filled in.

[0018] Step (10) Capping: Pour the rectangular top cover 14 of the arched retaining dam 1 and reserve the top rectangular hole 18;

[0019] Step (11) Road surface demolding: Remove the formwork of road panel 38;

[0020] Step (12) Construction of the arch structure 37: Erect steel arch frame, arrange connecting steel bars and steel mesh, erect external formwork, spray concrete and reserve rectangular frame 44;

[0021] Step (13) Construction of the rolling stone protection net 43: Install the rolling stone protection net 43 on the rectangular frame 44 of the arch structure 37.

[0022] The beneficial effects of the present invention are as follows: The present invention has a simple structure, strong practicality, and is safe and reliable. It can be applied to roads prone to debris flow disasters. Its advantages are: (1) When subjected to debris flow impact, the arched retaining dam can block the impact of debris flow. The vertical arched structure is more rationally stressed than ordinary gravity dams and can decompose the impact force of debris flow. The locally sourced crushed stone filler has good ductility and shock absorption performance and is relatively inexpensive. The combination of the three makes its blocking capacity and cost superior to traditional gravity dams and masonry dams, achieving efficient blocking and buffering, thereby ensuring that the roadbed and road surface will not be damaged by debris flow impact, providing conditions for safe passage of vehicles; (2) The sliding support structure can ensure that the road surface will not be damaged as a whole due to dam vibration (such as road tilting), and the self-returning device can ensure that the road surface can return to its initial position after being subjected to debris flow disasters, preventing The road support piles are in an eccentric state for a long time. The combination of the two can improve the safety of the road and the comfort of vehicle passage; (3) The airbag structure has the function of buffering and shock absorption, which is used to prevent the support pile body from being damaged when the barrier dam has a large horizontal displacement; (4) The arch-type protective structure can effectively decompose the impact force of the rolling stones on the protective net, avoid some of the splashed rolling stones from causing safety hazards to the road passage, and the inclined arch can prevent the rolling stones from accumulating on the protective net, avoid increasing the burden on the roadbed, and ensure driving safety. In order to ensure the light and ventilation needs in the arch, one side of the arch is set as a steel wire protective net; (5) The combination of crushed stone filling and seepage ditch can give full play to the effect of water permeability and pressure reduction of the dam structure after being impacted by debris flow, realize the separation of mud and sand and water, and effectively reduce the static pressure of mud. This structure can be used as a good means to provide a new idea for road protection against debris flow. Attached Figure Description

[0023] Figure 1 This is a perspective view of the structure of the invention from the airflow-facing side. Figure 2 This is a perspective view of the structure of the present invention from the backflow side. Figure 3 This is a cross-sectional elevation view of the structure of the present invention at the location of the fixed support pile; Figure 4 This is a cross-sectional elevation view of the structure of the present invention at the location of the culvert; Figure 5 This is a cross-sectional elevation view of the structure of this invention at the location of the rolling stone protection net; Figure 6 This is a front view of the upstream face of an arched retaining dam; Figure 7 This is a front view of the backflow side of an arched retaining dam; Figure 8 This is a detailed view of a drainage ditch. Figure 9 This is a detailed cross-sectional view of a drainage ditch. Figure 10 This is a detailed drawing of the frontal structure of the arched pavement; Figure 11 This is a detailed drawing of the backflow side structure of the arched roadway; Figure 12 Diagram showing the connection between the sliding pile and the road surface; Figure 13 This is a detailed top view of a sliding support. Figure 14 This is a sectional elevation view of the groove of the sliding bearing. Reference numerals: 1. Arched retaining dam; 2. Airbag buffer structure; 3. Fixed support pile; 4. Sliding support pile; 5. Arch-type pavement structure; 6. Box-type structure; 7. Crushed stone filling; 8. Culvert; 9. Retaining shell; 10. Foundation shell; 11. Arched wall panel; 12. Buttress-type retaining wall structure; 13. Rectangular top cover; 14. Circular drainage hole; 15. Culvert-type rectangular hole; 16. Drainage ditch-type rectangular hole; 17. Rectangular hole; 18. Type I rectangular plate; 19a. Type II rectangular plate; 19b. Type III rectangular plate; 19c. Type I plate; 20a. Type II plate; 20. Type II plate. 20b plate, 21 filter layer, 22 permeable hole, 23 vertical rectangular channel, 24 culvert-type horizontal rectangular channel, 25 seepage trench-type horizontal rectangular channel, 26 sleeve, 27 airbag, 28 ball bearing sliding support, 29 rectangular pile, 30 slot, 31 base, 32 steel ball, 33 thin steel plate, 34 groove, 35 I-beam embedded part, 36 self-returning pavement, 37 arch structure, 38 pavement panel, 39 self-returning structure, 40 limiter, 41 return spring, 42 framed arch, 43 rolling stone protection net, 44 rectangular frame. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the present invention. Modifications, equivalent substitutions, and improvements made within the principles of the present invention are all within the protection scope of the present invention.

[0025] like Figures 1 to 14As shown, this invention provides a debris flow retaining dam with a self-returning pavement structure and a construction method, including an arched retaining dam 1, an airbag buffer structure 2, fixed support piles 3, sliding support piles 4, and an arched pavement structure 5; characterized in that the arched retaining dam 1 is composed of a box-shaped structure 6, crushed stone filling material 7, culverts 8, and seepage trenches 9, wherein the box-shaped structure 6 is composed of a retaining shell 10 and a foundation shell 11, wherein the retaining shell 10 is a hollow box-shaped structure with an open bottom, which is composed of an arched wall panel 12, a buttress-type retaining wall panel 13, and a rectangular top cover 14, the arched wall panel 12 is a wall panel with an arched cross-section and a cross-section perpendicular to the ground, its surface is provided with circular drainage holes 15 arranged in a quincunx pattern, and culvert-type rectangular holes 16 are spaced apart at the bottom of the wall surface, its wall surface The normal direction of the wall is the direction of debris flow impact. The buttress wall panel 13 is a common buttress wall with circular drainage holes 15 arranged in a quincunx pattern on its surface. Culvert-type rectangular holes 16 are spaced at intervals at the bottom of the wall, and seepage trench-type rectangular holes 17 are arranged in a quincunx pattern in the middle of the wall. The normal direction of the wall surface is the direction of debris flow impact. The rectangular top cover 14 is a thin plate with a rectangular cross-section, parallel to the ground, and its long side parallel to the upstream and downstream sides of the dam. Rectangular holes 18 are spaced at intervals near the edges of the upstream and downstream sides. The top of the arched wall panel 12 and the top of the buttress wall panel 13 are directly connected to the bottom edge of the long side of the horizontally arranged rectangular top cover 14 to jointly form the dam shell 10. The arched wall panel 12 is the upstream side of the dam shell 10. The wall panels of the flow surface, the buttress-type retaining wall panel 13, are the wall panels on the back side of the retaining shell 10. The top surface of the retaining shell 10 is a rectangular top cover 14. The foundation shell 11 is a rectangular hollow box structure with a partially open top surface, which is composed of a first type of rectangular plate 19a, a second type of rectangular plate 19b, and a third type of rectangular plate 19c. The first type of rectangular plate 19a is a common rectangular wall panel perpendicular to the horizontal plane, and the normal direction of its wall surface is the direction of debris flow impact. The second type of rectangular plate 19b is a rectangular thin plate parallel to the horizontal plane and with its long side parallel to the front and back sides of the retaining dam. Its surface is provided with bottom rectangular holes 18 at intervals near the front and back sides. The third type of rectangular plate 19c is a rectangular plate parallel to the horizontal plane and with its long side parallel to the front and back sides of the retaining dam. The rectangular thin plates on the front and back sides of the debris flow have dimensions smaller than those of the second type of rectangular plate 19b along the debris flow impact direction. The first type of rectangular plates 19a are the front and back walls of the foundation shell 11, respectively. The bottoms of the two first type of rectangular plates 19a are connected to the long edge of the top surface of the second type of rectangular plate 19b. The long edge of the front side of the bottom surface of the third type of rectangular plate 19c is connected to the top of the front side of the first type of rectangular plate 19a. The back side of the third type of rectangular plate 19c is empty. Together, they form the foundation shell 11. The barrier shell 10 is located above the ground, and the foundation shell 11 is buried below the ground. The bottom of the arched wall plate 12 of the barrier shell 10 is connected to the long edge of the back side of the top surface of the third type of rectangular plate 19c of the foundation shell 11.The bottom of the buttress-type retaining wall panel 13 of the retaining shell 10 is directly connected to the top of the first type rectangular plate 19a on the backflow side of the foundation shell 11. The rectangular hole 18 at the top of the retaining shell 10 and the rectangular hole 18 at the bottom of the foundation shell 11 completely overlap from a top-view angle. The crushed stone filler 7 is composed of locally sourced crushed stone and soil. The culvert 8 is a conventional water pipe with a rectangular cross-section. The seepage ditch 9 is a water pipe with a rectangular cross-section, which is composed of a first type plate 20a, a second type plate 20b, and a filter layer 21. Plate 20a is a thin plate with a rectangular cross-section. Permeable holes 22 are spaced at intervals along the direction perpendicular to the pipe cross-section of plate 20a. Plate 20b is a common thin plate with a rectangular cross-section parallel to the horizontal plane. The filter layer 21 is a thin layer with a rectangular cross-section and a certain thickness, composed of layers of medium sand, coarse sand, and gravel. Plates 20a are the top and side plates of the seepage trench 9, respectively. Plate 20b is the bottom plate of the seepage trench 9. The bottom surface of the top plate and the top surface of the bottom plate are located on the left and right sides along the long side. The edges are connected to the top and bottom of the side plate along the long side, respectively. The upper surface of the filter layer 21 is bonded to the bottom surface of the top plate and the inner side of the side plate, respectively, thus forming the seepage trench 9. The box-shaped structure 6 is filled with crushed stone filler 7, and vertical rectangular channels 23 perpendicular to the ground are reserved at the positions corresponding to the rectangular holes 18. Horizontal rectangular channels 24 perpendicular to the upstream face of the dam are reserved at the positions corresponding to the culvert-type rectangular holes 16. Vertical channels 24 perpendicular to the upstream face of the dam are reserved at the positions corresponding to the seepage trench-type rectangular holes 17. The permeable duct 25 is a transverse rectangular channel of seepage groove. The culvert 8 has its pipe axis perpendicular to the flow-facing surface of the retaining shell 10 and passes sequentially through the culvert-type rectangular hole 16 of the arched wall panel 12, the culvert-type transverse rectangular channel 24 of the crushed stone filling 7, and the culvert-type rectangular hole 16 of the buttress-type retaining wall panel 13. The permeable duct 9 has its pipe axis perpendicular to the flow-facing surface of the retaining shell 10 and passes sequentially through the permeable duct-type transverse rectangular channel 25 of the crushed stone filling 7 and the permeable duct-type rectangular hole 17 of the buttress-type retaining wall panel 13.

[0026] like Figure 1 , Figure 3 As shown, the airbag buffer structure 2 consists of a sleeve 26 and an airbag 27. The sleeve 26 is a rectangular hollow steel sleeve, and the airbag 27 is a cylindrical rubber inflatable structure with a rectangular ring cross-section. The cylindrical outer wall of the airbag 27 is connected to the inner wall of the sleeve 26, thus forming the airbag buffer structure 2 together.

[0027] like Figure 1 As shown, fixed support pile 3 is an ordinary pile with a rectangular cross-section.

[0028] like Figures 1 to 14As shown, the sliding support pile 4 consists of a ball-type sliding bearing 28, a rectangular pile 29, and a groove 30. The ball-type sliding bearing 28 consists of a base 31, steel balls 32, and a thin steel plate 33. The base 31 is a thin plate with a rectangular cross-section. A groove 34 is provided on the top surface of the base 31 along the direction of debris flow impact. The steel balls 32 are steel balls with rotating shafts. The thin steel plate 33 is an ultra-thin steel plate with a rectangular cross-section. A row of steel balls 32 is placed inside each groove 34 of the base 31. The centroid height of the steel balls 32 is lower than the top surface of the base 31. The sides of the base 31 are... A thin steel plate 33 surrounds the rectangular pile 29, which is a pile with a rectangular cross-section. The slot 30 is composed of vertical I-beam embedded parts 35 arranged in a rectangular ring shape. One side of the flange of the I-beam embedded part 35 faces the inside of the ring. A part of the body of the I-beam embedded part 35 of the slot 30 is embedded in the top of the rectangular pile 29. The ball bearing sliding support 28 is installed in the slot 30 at the top of the rectangular pile 29. The thin steel plate 33 of the ball bearing sliding support 28 is welded together with the flange of the I-beam embedded part 35 of the slot 30 to form the sliding support pile 4.

[0029] The arch-type pavement structure 5 consists of a self-returning pavement 36 and an arch structure 37. The self-returning pavement 36 consists of a pavement panel 38 and a self-returning structure 39. The pavement panel 38 is a rectangular slab cast on-site. The self-returning structure 39 consists of a limiter 40 and a return spring 41. The limiter 40 consists of two pairs of L-shaped steel plates, which are inverted and symmetrically arranged along the direction of debris flow impact. The return spring 41 consists of two pairs of helical springs, symmetrically arranged. One end of each return spring 41 is fixed to the long side steel plate of the L-shaped plate at the end of the limiter 40, and the other end is left unattended, thus forming the self-returning structure 39. The limiter 40 of the structure 39 is fixed to the edge of the bottom surface of the road panel 38 near the back flow side by bolts, thus forming the self-returning road surface 36. The arch structure 37 consists of a framed arch 42 and a rolling stone protection net 43. The framed arch 42 is an arched open opening. A row of rectangular frames 44 is set at intervals on the arch on the front flow side. The rolling stone protection net 43 is composed of high-strength iron wires. The rolling stone protection net 43 is installed on the rectangular frames 44 of the framed arch 42. The arch toes on both sides of the arch structure 37 are directly connected to the front and back flow sides of the top surface of the road panel 38 of the self-returning road surface 36, and are cast in one piece on site.

[0030] like Figures 1 to 14As shown, the sleeve 26 of the airbag buffer structure 2 is inserted into the reserved vertical rectangular channel 23 of the arched barrier dam 1. The fixed support pile 3 is inserted into the central rectangular ring of the airbag 27 of the airbag buffer structure 2 near the upstream side. The pile body of the fixed support pile 3 passes through the arched barrier dam 1 and is supported in the bedrock at the bottom of the arched barrier dam 1. The rectangular pile 29 of the sliding support pile 4 is inserted into the central rectangular ring of the airbag 27 of the airbag buffer structure 2 near the downstream side. The rectangular pile 29 of the sliding support pile 4 passes through the arched barrier dam 1 and is supported at the bottom of the arched barrier dam 1. In the bedrock, the bottom surface of the pavement panel 38 of the arch-type pavement structure 5 near the edge of the upstream side is connected to the top surface of the fixed support pile 3 and is cast integrally. The bottom surface of the pavement panel 38 of the arch-type pavement structure 5 near the edge of the downstream side is connected to the top surface of the ball-type sliding bearing 28 at the top of the sliding support pile 4. The connection method is a sliding connection. The empty end of the return spring 41 of the arch-type pavement structure 5 is connected to the top of both sides of the sliding support pile 4 along the debris flow impact direction. The axis of symmetry of the limiter 40 of the arch-type pavement structure 5 coincides with the center of the cross section of the sliding support pile 4.

[0031] like Figure 1 , Figure 2 As shown, the dimensions of the cast-in-place reinforced concrete box-type structure 6 of the arched retaining dam 1 are determined according to the engineering design requirements; the dimensions of the box-type structure 6 are 30-40m in length and 20-30m in width; the lengths of the sliding support piles 4 and the fixed support piles 3 are 11-15m, and the cross-sectional dimensions of the piles are 2-4m in length and 2-3m in width; the center-to-center distance between adjacent piles of the same type is 6-8m; the height of the box-type structure 6 is 15-18m, and the height of the self-returning pavement 36 is 16-19m.

[0032] like Figures 1-5 As shown, the upper part of the sliding support pile 4 and the fixed support pile 3 is an arch-shaped pavement structure 5. The pavement slab 38 and the fixed support pile 3 are integrally cast reinforced concrete, and the pavement width is 15-20m.

[0033] like Figure 3 As shown, the portion of the sliding support pile 4 and the fixed support pile 3 that passes through the box-shaped structure 6 is filled with an air bladder 27 between it and the sleeve 26. The sleeve 26 has a length of 4-5m and a width of 3-4m.

[0034] like Figures 3-5 As shown, the cement concrete pavement slab 38 is slidably connected to the sliding support pile 4, and directly connected to the fixed support pile 3, and is cast integrally.

[0035] like Figures 4 to 14 As shown, culverts 8 are arranged at intervals at the bottom of the retaining shell 10 and penetrate the entire arched retaining dam 1. The cross-sectional side length of culverts 8 is 30-50cm. Infiltration trenches 9 are arranged in a quincunx pattern in the middle of the retaining shell 10 and penetrate only the interior of the arched retaining dam and the backflow side wall. The cross-sectional side length of infiltration trenches 9 is 20-40cm.

[0036] like Figure 10 , 11 As shown, the arch-shaped road structure 5, which can block falling rocks, is 5-7m high and 15-20m wide. The rockfall protection net 43 is set on the side facing the debris flow. The net 43 is 4-5m long and 5-6m high, and the arch wall is 0.5-0.8m thick.

[0037] like Figure 10 , 11 As shown, the rolling stone protection net 43 is woven from steel wire or steel strand and has a diameter of 10-16mm.

[0038] The present invention relates to a canopy-type anti-skid structure with a road system and a construction method, such as... Figures 1 to 14 As shown, the steps are as follows:

[0039] Step (1) Survey and design: Survey the engineering geological conditions of the road and the mountain on the side of the road, the hydrological and meteorological conditions, determine the impact direction of debris flow and predict the maximum impact load, carry out calculation and design, and determine the height of the pile, the cross-sectional dimensions of the pile body and the pile spacing.

[0040] Step (2) Prefabricate ball bearing sliding support (28): Prefabricate according to the design dimensions and transport to the site for storage;

[0041] Step (3) Box-type structure (6) Construction: Excavate the soil to the design elevation of the bottom of the arched retaining dam (1), pour the bottom slab and side walls, and reserve the position corresponding to the bottom rectangular hole (18) when pouring the bottom slab, and reserve the corresponding positions of the drainage hole (15), culvert (8) and seepage ditch (9) on the side walls;

[0042] Step (4) Drilling and molding: The lower piles of the arched retaining dam (1) are drilled and cast, while the upper piles are cast using molding. Drill holes along the pre-reserved pile holes in the bottom plate, mold the upper part, and install the sleeve (26).

[0043] Step (5) Backfilling: Fill the box-shaped structure (6) with crushed stone filler (7) in layers according to the design requirements. During the backfilling process, culverts (8) and seepage trenches (9) should be poured in the corresponding positions in a timely manner.

[0044] Step (6) Sliding support pile (4) Construction: hoist and place the steel cage, pour the sliding support pile, set the I-beam embedded parts (35) at the pile top position as required, and hoist and weld the ball-type sliding bearing (28);

[0045] Step (7) Road panel (38) Formwork: Form the mold according to the design requirements and set the panel reinforcement;

[0046] Step (8) Construction of fixed support piles (3) and road slabs (38): hoist and place the steel cage, and pour the fixed support piles (3) and road slabs (38) as a whole;

[0047] Step (9) Pile body demolding: After the curing is completed, the pile body formwork is removed and the airbag (27) structure that meets the design requirements is filled in.

[0048] Step (10) Capping: Pour the rectangular top cover (14) of the arched retaining dam (1) and reserve the top rectangular hole (18);

[0049] Step (11) Road surface demolding: Remove the formwork of the road slab (38);

[0050] Step (12) Construction of the arch structure (37): Erect steel arch frame, arrange connecting steel bars and steel mesh, erect external formwork, spray concrete and reserve rectangular frame (44);

[0051] Step (13) Construction of the rockfall protection net (43): Install the rockfall protection net (43) on the rectangular frame (44) of the arch structure (37).

[0052] The present invention relates to a debris flow retaining dam with a self-recovering pavement structure and a construction method thereof. The construction sequence should preferably employ a reverse construction method, with layered construction. The steps are as follows:

[0053] (1) Construction of arched retaining dam 1. The dimensions of the cast-in-place reinforced concrete box structure 6 are determined according to the engineering design requirements. The dam body is made of concrete with a strength grade of C30 or above. The box structure 6 is filled with crushed stone filler 7. The foundation shell 11 of the box structure 6 is buried below the ground. The retaining shell 10 is exposed above the ground. Sleeves 26 are provided near the walls on the upstream and downstream sides. Rectangular steel sleeves 26 are prefabricated according to the dimensions. Drainage holes 15 are set on the walls of the box structure.

[0054] (2) Construction of the road support system: The dimensions of the sliding support pile 4, the fixed support pile 3 and the road panel 38 are determined according to the engineering design requirements. The sliding support pile 4 and the fixed support pile 3 are installed inside the rectangular steel sleeve 26. The outside of the sleeve 26 is filled with crushed stone filler 7 for blocking and shock absorption. The airbag 27 is made according to the engineering design requirements and filled into the sleeve 26. The prefabricated ball-shaped sliding bearing 28 is installed on the upper part of the sliding support pile 4 and connected to the road panel 38.

[0055] (3) Construction of arch-type pavement structure 5: The upper part of the pile is the pavement panel 38. The size of the rectangular frame 44 is determined according to the engineering design requirements. The arch and the pavement panel 38 are constructed and directly connected. A rectangular frame 44 is reserved on the flow-facing side of the arch. The size of the rolling stone protection net 43 is determined according to the engineering design requirements. The prefabricated rolling stone protection net 43 is set in the rectangular frame 44.

[0056] The working principle of the debris flow barrier dam with self-returning road structure of the present invention is as follows: (1) Barrier principle: When impacted by debris flow, the arch barrier dam can play a blocking and buffering role. The arch barrier form is more reasonable in terms of force distribution and can effectively decompose the normal impact force on the front wall. This reduces the horizontal impact force on the dam body and improves the barrier effect. Based on the above principle, this structure can intercept debris flow upstream more efficiently, reduce the impact of debris flow on the dam body, and thus protect the support piles and roads from damage; (2) Vibration reduction principle: The crushed stone filling in the box structure has good ductility and has a good buffering and vibration reduction effect. The filling material can be sourced locally, which is simple and convenient, and has economic and practicality. The pile and the casing are filled with airbags, which utilize the damping effect of the airbags and the damping effect of the airbag exhaust throttling. (2) Absorbing the kinetic energy generated by the impact of debris flow and dam deformation, thereby reducing the impact on the pile body and playing a good role in shock absorption; (3) Safe traffic principle: Due to the role of the retaining dam, crushed stone filling and airbag, the roadbed support pile is not easily damaged by debris flow, ensuring the stability of the roadbed. When the rolling stone falls onto the arch protection structure, the rolling stone protection net of the arch can absorb the impact energy of the rolling stone and intercept the rolling stone. Due to the geometry of the arch, the rolling stone can slide off, thus not increasing the burden on the roadbed. The single-sided sliding support structure and self-returning limit device can ensure that the road surface does not suffer overall damage (such as the tilting damage of the road surface), prevent the road surface from dislodging from the sliding support pile due to excessive displacement, and allow the sliding support pile to automatically return to the initial position after the debris flow is cleared. The above principles combined can ensure safe traffic.

Claims

1. A debris flow retaining dam with a self-returning pavement structure, comprising an arch retaining dam (1), an airbag buffer structure (2), fixed support piles (3), sliding support piles (4) and an arch-type pavement structure (5), characterized in that The arch retaining dam (1) is composed of a box structure (6), crushed stone filling (7), a culvert (8) and a seepage ditch (9), wherein the box structure (6) is composed of a retaining shell (10) and a foundation shell (11), wherein the retaining shell (10) is a hollow box structure with an opening at the bottom, which is composed of an arch wall panel (12), a buttress retaining wall panel (13) and a rectangular top cover (14), wherein the arch wall panel (12) is a wall panel with an arched cross section and a cross section perpendicular to the ground, wherein the surface of the arch wall panel is provided with circular drainage holes (15) arranged in a plum blossom shape, and culvert-type rectangular holes (16) are arranged at intervals at the bottom of the wall surface, wherein the normal direction of the wall surface is the impact direction of the debris flow, and the buttress retaining wall panel (13) is an ordinary buttress retaining wall, wherein the wall surface of the arch wall panel is provided with drainage holes (15) arranged in a plum blossom shape. 15), culvert-type rectangular holes (16) are arranged at intervals at the bottom of the wall, and seepage ditch-type rectangular holes (17) are arranged in a plum blossom shape in the middle of the wall. The normal direction of the wall is the impact direction of the debris flow. The rectangular top cover (14) is a thin plate with a rectangular cross-section, parallel to the ground, and with its long side parallel to the upstream and downstream sides of the retaining dam. Rectangular holes (18) are arranged at intervals near the edges of the upstream and downstream sides. The top of the arched wall panel (12) and the top of the buttress-type retaining wall panel (13) are directly connected to the edges of the bottom of the long side of the horizontally arranged rectangular top cover (14) to form a retaining shell (10). The arched wall panel (12) is the wall panel of the upstream side of the retaining shell (10), and the buttress-type retaining wall panel (13) is the wall panel of the downstream side of the retaining shell (10). The top surface of the retaining shell (10) is a rectangular top cover (14), and the base shell (11) is a rectangular hollow box-shaped structure with a partially open top surface, which is composed of a first type of rectangular plate (19a), a second type of rectangular plate (19b) and a third type of rectangular plate (19c). The first type of rectangular plate (19a) is an ordinary rectangular wall plate perpendicular to the horizontal plane, and the normal direction of its wall surface is the impact direction of the debris flow. The second type of rectangular plate (19b) is a rectangular thin plate parallel to the horizontal plane and the long side direction is parallel to the upstream and downstream surfaces of the retaining dam, and bottom rectangular holes (18) are respectively arranged at intervals on the surface near the upstream side and the downstream side. The third type of rectangular plate (19c) is a rectangular thin plate parallel to the horizontal plane and the long side direction is parallel to the upstream and downstream surfaces of the retaining dam. The first rectangular plates (19a) are respectively the upstream and downstream walls of the basic shell (11); the bottoms of the two first rectangular plates (19a) are respectively connected to the long side edges of the top surface of the second rectangular plate (19b); the long side edge of the downstream side of the bottom surface of the third rectangular plate (19c) is connected to the top of the first rectangular plate (19a) on the upstream side, thereby forming the basic shell (11); the blocking shell (10) is located above the ground, and the basic shell (11) is buried below the ground; the bottom of the arched wall panel (12) of the blocking shell (10) is connected to the long side edge of the downstream side of the top surface of the third rectangular plate (19c) of the basic shell (11);The bottom of the buttress-type retaining wall panel (13) of the retaining shell (10) is directly connected to the top of the first type rectangular plate (19a) on the back flow side of the base shell (11); the rectangular hole (18) at the top of the retaining shell (10) and the rectangular hole (18) at the bottom of the base shell (11) completely overlap when viewed from a top view; the crushed stone filler (7) is composed of crushed stone soil taken locally; the culvert (8) is an ordinary water pipe with a rectangular cross section; the infiltration ditch (9) is a water pipe with a rectangular cross section, which is composed of a first type plate (20a), a second type plate (20b) and a filter layer (21). The first type of plate (20a) is a thin plate with a rectangular cross section. The first type of plate (20a) is provided with water permeable holes (22) at intervals along the direction perpendicular to the pipe cross section. The second type of plate (20b) is an ordinary thin plate with a rectangular cross section and parallel to the horizontal plane. The filter layer (21) is a thin layer with a rectangular cross section and a certain thickness formed by layers of medium sand, coarse sand and gravel. The first type of plate (20a) is the top plate and the side plate of the infiltration ditch (9). The second type of plate (20b) is the bottom plate of the infiltration ditch (9). The bottom surface of the top plate and the top surface of the bottom plate are respectively disposed at the left and right edges along the long side direction. The top and bottom of the side plates are respectively connected along the long side direction, and the upper surface of the filter layer (21) is respectively bonded and connected to the bottom surface of the top plate and the inner side of the side plate, thereby forming a seepage ditch (9). The box-shaped structure (6) is filled with crushed stone filler (7), and a vertical rectangular channel (23) perpendicular to the ground is reserved at the position corresponding to the rectangular hole (18), a culvert-type transverse rectangular channel (24) perpendicular to the flow-facing surface of the dam body is reserved at the position corresponding to the culvert-type rectangular hole (16), and a seepage ditch-type transverse rectangular hole perpendicular to the flow-facing surface of the dam body is reserved at the position corresponding to the seepage ditch-type rectangular hole (17). The culvert (8) has a pipeline axis perpendicular to the flow-facing surface of the retaining shell (10), and the culvert (8) sequentially passes through the culvert-type rectangular hole (16) of the arch wallboard (12), the culvert-type transverse rectangular hole (24) of the crushed stone filler (7), and the culvert-type rectangular hole (16) of the buttress-type retaining wallboard (13); the pipeline axis of the seepage ditch (9) is perpendicular to the flow-facing surface of the retaining shell (10), and the seepage ditch (9) sequentially passes through the seepage ditch-type transverse rectangular hole (25) of the crushed stone filler (7) and the seepage ditch-type rectangular hole (17) of the buttress-type retaining wallboard (13); The airbag cushioning structure (2) is composed of a sleeve (26) and an airbag (27), wherein the sleeve (26) is a rectangular hollow steel sleeve, and the airbag (27) is a columnar rubber inflating structure with a rectangular ring cross section, and the columnar outer wall of the airbag (27) is connected to the inner wall of the sleeve (26), thereby forming the airbag cushioning structure (2); The fixed support pile (3) is a common pile with a rectangular cross section; The sliding support pile (4) is composed of a ball-type sliding support (28), a rectangular pile (29) and a slot (30). The ball-type sliding support (28) is composed of a base (31), a steel ball (32) and a thin steel plate (33). The base (31) is a thin plate with a rectangular cross section. A groove (34) is arranged on the top surface of the base (31) along the impact direction of the debris flow. The steel ball (32) is a steel ball with a rotating shaft. The thin steel plate (33) is an ultra-thin steel plate with a rectangular cross section. A row of steel balls (32) are placed inside the grooves (34) of the base (31). The centroid height of the steel balls (32) is lower than the top surface of the base (31). The sides of the base (31) are The rectangular pile (29) is a pile with a rectangular cross section. The slot (30) is composed of vertical I-beam embedded parts (35) arranged in a rectangular ring shape. One side wing of the I-beam embedded part (35) faces the inner side of the ring. The part of the I-beam embedded part (35) of the slot (30) is embedded in the top of the rectangular pile (29). The ball-type sliding support (28) is mounted in the slot (30) at the top of the rectangular pile (29). The thin steel plate (33) of the ball-type sliding support (28) is welded with the wing of the I-beam embedded part (35) of the slot (30) to form a sliding support pile (4). The arch-hole type pavement structure (5) is composed of a self-returning pavement (36) and an arch-hole structure (37). The self-returning pavement (36) is composed of a road panel (38) and a self-returning structure (39). The road panel (38) is a rectangular plate cast on site. The self-returning structure (39) is composed of a stopper (40) and a return spring (41). The stopper (40) is composed of two L-shaped steel plates in a group. The L-shaped steel plates are inverted and symmetrically arranged along the impact direction of the debris flow. The return spring (41) is composed of two spiral springs in a group. One end of each return spring (41) is fixed to the L-shaped long side steel plate at the end of the stopper (40), and the other end is left vacant, thereby forming a self-returning structure (39). The self-returning structure The stopper (40) of the structure (39) is fixed to the edge of the bottom surface of the road panel (38) near the back flow side by bolts, thereby forming a self-returning road surface (36); the arch hole structure (37) is composed of a framed arch hole (42) and a rolling stone protection net (43); the framed arch hole (42) is an arched open hole, and a row of rectangular frames (44) are arranged on the arch hole on the front flow side; the rolling stone protection net (43) is composed of high-strength iron wires crossing each other; the rolling stone protection net (43) is installed on the frame (44) of the framed arch hole (42); the arch toes on both sides of the arch hole structure (37) are directly connected to the edges on both sides of the front flow side and the back flow side of the top surface of the road panel (38) of the self-returning road surface (36), and are cast in one piece on site; The sleeve (26) of the airbag buffer structure (2) is inserted into the reserved vertical rectangular channel (23) of the arch retaining dam (1), the fixed support pile (3) is inserted into the central rectangular ring of the airbag (27) of the airbag buffer structure (2) close to the upstream side, the pile body of the fixed support pile (3) passes through the arch retaining dam (1) and is supported in the bedrock at the bottom of the arch retaining dam (1), the rectangular pile (29) of the sliding support pile (4) is inserted into the central rectangular ring of the airbag (27) of the airbag buffer structure (2) close to the downstream side, and the pile body of the rectangular pile (29) of the sliding support pile (4) passes through the arch retaining dam (1) and is supported on the arch retaining dam (1). In the bedrock at the bottom, the bottom surface of the road panel (38) of the arch-hole type pavement structure (5) near the edge on the upstream side is connected to the top surface of the fixed support pile (3) and is cast as one piece, and the bottom surface of the road panel (38) of the arch-hole type pavement structure (5) near the edge on the downstream side is connected to the top surface of the ball-type sliding support (28) at the top of the sliding support pile (4), and the connection method is sliding connection. The idle end of the return spring (41) of the arch-hole type pavement structure (5) is connected to the top of both sides of the sliding support pile (4) along the impact direction of the debris flow, and the symmetry axis of the limiter (40) of the arch-hole type pavement structure (5) coincides with the center of the cross section of the sliding support pile (4).

2. The debris flow retaining dam with a self-returning pavement structure according to claim 1 is characterized in that The blocking shell (10) and the base shell (11) of the box-type structure (6) are both cast on-site using reinforced concrete. The structural dimensions of the base shell (11) along the debris flow impact direction are larger than those of the blocking shell (10), and the excess portion protrudes toward the flow-facing side. The dimensions of the rectangular hole (18) are the same as the cross-sectional dimensions of the reserved vertical rectangular channel (23). The culvert-type rectangular hole (16) and the seepage ditch-type rectangular hole (17) are the same as the cross-sectional dimensions of the culvert-type transverse rectangular channel (24) and the seepage ditch-type transverse rectangular channel (25).

3. The debris flow retaining dam with a self-returning pavement structure according to claim 1 is characterized in that The rectangular pile (29) of the sliding support pile (4) and the fixed support pile (3) are both reinforced concrete piles with rectangular cross-sections, and the thin steel plate (33) wrapped around the side of the ball-type sliding support (28) is welded together with the wing plate of the I-beam embedded part (35) of the slot (30) at the top of the rectangular pile (29).

4. The debris flow retaining dam with a self-returning pavement structure according to claim 1 is characterized in that The cross-sectional dimensions of the sleeve (26) are the same as those of the reserved vertical rectangular channel (23), and the cross-sectional dimensions of the sleeve (26) are larger than those of the rectangular piles (29) of the sliding support piles (4) and the fixed support piles (3), and the vertical length of the sleeve (26) is the same as the height of the arch retaining dam (1).

5. The debris flow retaining dam with a self-returning pavement structure according to claim 1 is characterized in that When the airbag (27) is filled with gas, its cross-sectional outer diameter is the same as the inner diameter of the casing (26), and the cross-sectional inner diameter of the airbag (27) is equal to the cross-sectional dimensions of the rectangular pile (29) of the sliding support pile (4) and the fixed support pile (3), and the vertical length of the airbag (27) is the same as the height of the arch retaining dam (1).

6. The construction method of the debris flow retaining dam with a self-returning pavement structure according to claim 1 is characterized in that: The steps are: Step (1) Survey and design: survey the engineering geological conditions of the road and the mountain on the side of the road, the hydrological and meteorological conditions, determine the impact direction of the debris flow and predict the maximum impact load, perform calculation and design, and determine the height of the pile, the cross-sectional dimensions of the pile body, and the distance between the piles; Step (2) prefabricate the ball-type sliding support (28): prefabricate in advance according to the design size, and transport to the site for storage; Step (3) construction of the box structure (6): excavating the soil to the designed elevation of the bottom of the arch retaining dam (1), casting the bottom plate and the side walls, reserving the corresponding positions of the bottom rectangular holes (18) when casting the bottom plate, and reserving the corresponding positions of the drainage holes (15), culverts (8) and seepage ditches (9) on the side walls; Step (4) drilling and molding: the lower pile body of the arch retaining dam (1) is bored and cast, and the upper pile body is molded and cast. The pile holes reserved along the bottom plate are drilled, the upper part is molded, and the casing (26) is installed; Step (5) backfilling: filling the box-shaped structure (6) with crushed stone filler (7) in layers according to the design requirements, and pouring culverts (8) and seepage ditches (9) at corresponding positions in a timely manner during the backfilling process; Step (6) Construction of sliding support piles (4): hoisting and placing the steel cage, casting the sliding support piles, setting the I-beam embedded parts (35) at the top of the piles as required, and hoisting and welding the ball-type sliding bearings (28); Step (7) road panel (38) molding: molding and setting panel reinforcement according to design requirements; Step (8) Construction of fixed support piles (3) and road slabs (38): hoisting and placing the steel cage, and integrally casting the fixed support piles (3) and road slabs (38); Step (9) Pile body demoulding: after the curing is completed, the pile body template is removed and filled with an air bag (27) structure that meets the design requirements; Step (10) capping: pouring a rectangular top cover (14) of the arch retaining dam (1) and reserving a rectangular hole (18) at the top; Step (11) road surface demoulding: removing the template of the road panel (38); Step (12) Construction of the arch structure (37): erecting a steel arch frame, arranging connecting steel bars and steel mesh, erecting an outer formwork, spraying concrete and reserving a frame (44); Step (13) Construction of the rock rolling protection net (43): Install the rock rolling protection net (43) on the frame (44) of the arch structure (37).

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