Railway roadbed slope protection engineering construction technology

Abstract

The invention relates to the technical field of railroad bed slope protection engineering, and discloses a railroad bed slope protection engineering construction process which comprises the following steps: S1, construction preparation: carrying out stability inspection on a mountain, dividing a slope protection engineering into a plurality of construction sections, carrying out rough lofting, releasing a slope red line position, and cleaning the ground surface in a red line range; surface soil is stripped and independently stored for subsequent greening backfilling; for an area with the gradient larger than 45 degrees or a geological fracture zone, an unmanned aerial vehicle is adopted for aerial photography to obtain a high-resolution image, and a slope three-dimensional model is generated through three-dimensional modeling. Through construction preparation, mountain check and complex geological area BIM simulation optimization are carried out; step-by-step layering and novel steel structure supporting are used for earth-rock excavation; the retaining wall is poured layer by layer according to height and reinforcement measures are perfected; the foot wall is reasonably constructed, tamped and backfilled, all links have a synergistic effect, the goals of high efficiency and safety are achieved, and the requirements of complex areas are met.

Description

Technical Field

[0001] The invention relates to the technical field of railway roadbed slope protection engineering, in particular to a railway roadbed slope protection engineering construction process. Background Art

[0002] Railway embankment slope protection projects are a crucial component of railway construction. Their purpose is to prevent slope collapse or landslides caused by factors such as rainwater erosion and geological instability, thereby ensuring safe railway operations. Currently, slope protection technologies primarily include vegetation protection, stone masonry, and concrete protection. Vegetation protection involves planting grass or shrubs to stabilize the soil, offering low cost but limited erosion resistance. Stone masonry uses stacked stones, resulting in a stable structure but a long construction period. Concrete protection offers high strength but is expensive and has poor ecological benefits. With the rapid development of railway construction, particularly in areas with complex terrain, balancing protection effectiveness, construction efficiency, and cost has become a technical challenge.

[0003] Existing technologies typically employ the following approaches for slope protection: First, vegetation protection, which involves laying turf or planting shrubs on the slope surface to stabilize the soil using plant roots; second, stone masonry, which involves manually or mechanically stacking stones to create a slope protection structure; this offers improved stability but low construction efficiency; and third, concrete protection, which involves covering the slope with cast-in-place concrete or precast concrete blocks, offering high protection strength. Additionally, composite protection technologies such as geogrids and retaining walls are available, but these are often complex to construct and challenging to implement near highways or expressways. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a railway roadbed slope protection engineering construction process to solve the problem that the existing technology is often complex in construction and difficult to implement in areas adjacent to high-grade highways or expressways.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A railway roadbed slope protection engineering construction process comprises the following steps: S1. Construction Preparation: Conduct a stability check on the mountain, divide the slope protection project into multiple construction sections, conduct a rough stakeout, lay out the slope redline position, clean the surface within the redline, strip the topsoil and store it separately for subsequent greening backfill. For areas with slopes greater than 45° or geological fracture zones, use drones to obtain high-resolution aerial images, generate a 3D slope model through 3D modeling, import it into the BIM platform, combine geological survey data with design drawings, simulate and optimize the construction plan, accurately arrange bamboo piles, and record relevant data. S2. Excavation of earthwork: Slopes shall be laid out according to the designed slope, excavated step by step from top to bottom, and protected by layers of construction platforms. The excavation depth and sequence of each layer shall be controlled. For slopes with a height of 5m or more, a new type of prefabricated steel structure temporary support system shall be used. S3. Concrete Arched Water-Intercepting Skeleton Slope Protection Construction: Excavate and trim the foundation trench, install it using different formwork, pour concrete in layers and sections from bottom to top, and vibrate it. Concrete is poured in sequence, along with the subsequent platform and intercepting ditch. Parameters for the concrete arched water-intercepting skeleton are set, and ecological slope protection measures are implemented, including the installation of ecological holes, ecological bag slope protection, native plant buffer zones, grass seed spraying, and shrub planting. S4. Concrete retaining wall construction: Use concrete gravity retaining wall support and backfill the embankment retaining wall. For retaining walls of different heights, adopt a layered pouring method. Use PFF integral filter layer construction, use concrete spraying to reinforce weak soil layers, and set expansion joints in the retaining wall and perform caulking treatment. S5. Concrete footing wall construction: Determine the footing wall size and use concrete gravity retaining wall support, carry out foundation excavation and formwork installation, install drainage pipes according to design requirements, pour concrete in multiple layers according to the height of the retaining wall and vibrate it. After the retaining wall foundation is poured, immediately backfill the foundation pit and compact it in layers.

[0006] Through the above-mentioned plan, during the construction preparation phase, safety was ensured through mountain inspections and segmented stakeouts. In complex geological areas, drone aerial photography, 3D modeling, and BIM simulation optimization were used to precisely arrange bamboo piles and mitigate risks. During excavation, a layered approach was implemented from top to bottom, with the use of new steel structures for temporary support, improving safety and efficiency in high-slope construction. The arched water-cutting skeleton slope protection was meticulously constructed, incorporating ecological slope protection measures to balance protection and ecology, minimizing ecological damage. Retaining walls were constructed by pouring them in layers according to height, with filter layers, spray reinforcement, and expansion joint treatment to enhance stability. The footing walls were constructed with appropriate dimensions, poured in layers, and drain pipes installed, with timely backfill and compaction to ensure overall slope stability. Each component of this plan worked closely together to ensure efficient and safe construction.

[0007] Preferably, the length of the construction section is controlled at 50-80m; the thickness of the topsoil stripping is controlled at 30-50cm; high-resolution images with a resolution of not less than 0.1m are obtained by drone aerial photography; bamboo piles are arranged in the BIM model, their driving position, depth and spacing are simulated, and the distance and angle data from the bamboo piles to the center piles are recorded.

[0008] Preferably, the excavation depth of each layer is controlled at 3m to 4m; the new prefabricated steel structure temporary support system includes standardized H-shaped steel columns, channel steel cross braces and diagonal braces, which are connected by bolts, with a column spacing of 1.5m and a cross brace spacing of 2m; for narrow parts of the excavation working face, manual excavation is carried out in conjunction with small mechanical equipment, and micro-piles are set up for protection; for rocks of different strengths, controlled blasting technology is used for excavation, and sprayed anchor support is used for protection; for vibration and noise sensitive areas, silent blasting technology is used for excavation, and vibration isolation ditches are set up for protection; the width of the temporary drainage ditch is 300mm, and circular drainage ditches are set up at the top and foot of the slope on the hillside. Single-sided or double-sided drainage ditches are set up on the on-site roads and branch roads according to different requirements, and the slope of the ditch bottom is 2%-8%.

[0009] Preferably, the narrow part of the excavation working face is turned over by an excavator; the slope of the temporary slope is controlled at 1:1, and the excavation is first carried out to 50cm to 100cm away from the designed slope line, and then the slope is repaired mechanically and manually; the strongly weathered rock with a strength of 5MPa to 30MPa is excavated in layers using a rock drilling machine in combination with an excavator.

[0010] Preferably, the concrete arch water-cutting skeleton adopts C30 concrete; in the middle of the slope, the main skeleton is 0.6m thick, the arch skeleton is 0.4m thick, and the net spacing is 3m; at the top and bottom of the slope, the main skeleton is 0.5m thick, the arch skeleton is 0.35m thick, and the net spacing is 3.5m; an expansion joint is set every 3-5 arches, with a joint width of 0.02m, filled with asphalt hemp tendons, and a step is set every 80m; the diameter of the ecological hole is 10-15cm, and the hole spacing is 0.5-0.8m; the backfill planting soil in the skeleton is mixed with 30% humus soil and 20% organic fertilizer; the ecological bag is made of degradable polypropylene fiber material, filled with nutrient soil and grass seeds; a 2m wide native plant buffer zone is set at the foot of the slope; the grass seeds and fertilizers are mixed evenly and then mechanically sprayed, and covered with non-woven fabric after spraying; the shrubs are Sophora japonica, which are laid out at a spacing of 0.6m×0.6m, with 2 plants planted in each hole, and watered for health after planting.

[0011] Preferably, for retaining walls with a height of less than or equal to 3m, a steel mold is used for one-time layer casting, and the thickness of each layer does not exceed 50cm; for retaining walls greater than 3m, a steel mold is used for multiple layer casting, and the height of each layer does not exceed 3m; the PFF integral filter layer is laid vertically along the back slope of the wall, and the two pieces are fixed at the junction with U-shaped anchor nails or cement steel nails, and the spacing between the fixing nails is not more than 5.0m. The overlapping parts between the pieces are sealed with tape, and the upper port of the composite filter layer is temporarily wrapped and sealed with geotextile or plastic film; when spraying concrete for reinforcement, first use water cement to fix the two pieces. Lubricate the hopper and feed pipeline of the sprayer with clean cement slurry in a ratio of 1:2, with an air pressure of 0.9 MPa and a water pressure of 0.4 MPa. Adjust the spraying speed and control the amount of accelerator added. The spraying operation is carried out in sections and pieces from bottom to top. Adjust the distance and angle between the spray gun and the sprayed surface. The distance between the nozzle and the sprayed surface is 0.6 to 1.0 m, and the angle between the nozzle and the vertical line of the sprayed surface is 10 to 15 degrees. Spray in layers with a thickness of 3 to 5 cm. After the spraying construction is completed, seal the joints. The expansion joints are 20 mm wide and plugged with asphalt tendons.

[0012] Preferably, the foot wall is 1.5m high, 0.8m deep and 0.7m thick; when the foundation is excavated, the mechanical excavation is carried out to 30cm from the base and then leveled and compacted; the formwork adopts a 1.5m×0.6m standard steel formwork, and combined wooden formwork is used at both ends, and the formwork is erected at one time; φ25mm HRB400 steel bars are embedded in the concrete poured in the upper layer for formwork tensioning, and φ48.3 steel pipes are used as internal supports inside the formwork, which are removed after the concrete is poured and covers the supporting steel pipes; after the formwork is installed, supports are set every 1m in the horizontal direction.

[0013] Preferably, the drain pipe is installed at the position of the drain hole according to the designed spacing, discharged to the ground at a slope of 4%, fixed in position with φ10HPB steel bars, and the pipe opening is sealed before concrete pouring.

[0014] Preferably, the concrete footing wall is constructed in three times according to the height of the retaining wall, and each pouring is carried out in layers from bottom to top, with the thickness of each layer not exceeding 50 cm. The upper layer of concrete is poured before the lower layer of concrete begins to set, and is vibrated with an inserted vibrator; after the retaining wall foundation is poured, the foundation pit is backfilled immediately, and the backfilling process is carried out by layer compaction, with a compaction degree of not less than 90%.

[0015] Preferably, after the concrete is poured, it is cured. After the concrete is poured, the concrete surface should be covered with water for curing after the cement reaches the final setting time. The curing time is not less than 7 days, and the concrete surface should be kept moist during curing.

[0016] The present invention provides a construction process for railway roadbed slope protection engineering, which has the following beneficial effects: 1. This invention uses mountain inspection and BIM simulation optimization in complex geological areas to accurately deploy and reduce risks during construction preparation. Earthwork excavation uses step-by-step layering and new steel structure support to ensure safe and efficient construction on high slopes. Retaining walls are cast in layers according to height and reinforced with perfect measures to enhance stability. The footing walls are rationally constructed and compacted with backfill to ensure the overall stability of the slope. All links work together to achieve the goals of efficiency and safety, adapting to the needs of complex areas.

[0017] 2. The present invention adopts a series of ecological measures in the construction of concrete arch water-cutting skeleton slope protection, such as setting ecological holes in the skeleton, using ecological bag slope protection technology, setting up native plant buffer zones, and selecting grass species and shrubs suitable for local growth for greening. These measures not only effectively prevent soil erosion and protect the stability of the slope, but also promote the restoration and improvement of the ecological environment, meeting the requirements of sustainable development.

[0018] 3. The present invention adopts a new type of prefabricated steel structure temporary support system and concrete gravity retaining wall support with different casting methods for slopes of different heights, thereby solving the problem of slope support under different geological conditions. At the same time, concrete spraying reinforcement technology is adopted in the treatment of soft soil layers, and detailed regulations are made on the spraying parameters and construction process to ensure construction quality, improve the overall quality and safety of the slope protection project, and extend the service life of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Please see the attached Figure 1 The embodiment of the present invention provides a construction process for a railway roadbed slope protection project, comprising the following steps: S1. Construction Preparation: Conduct a stability check on the mountain, divide the slope protection project into multiple construction sections, conduct a rough stakeout, lay out the slope redline position, clean the surface within the redline, strip the topsoil and store it separately for subsequent greening backfill. For areas with slopes greater than 45° or geological fracture zones, use drones to obtain high-resolution aerial images, generate a 3D slope model through 3D modeling, import it into the BIM platform, combine geological survey data with design drawings, simulate and optimize the construction plan, accurately arrange bamboo piles, and record relevant data. S2. Excavation of earthwork: Slopes shall be laid out according to the designed slope, excavated step by step from top to bottom, and protected by layers of construction platforms. The excavation depth and sequence of each layer shall be controlled. For slopes with a height of 5m or more, a new type of prefabricated steel structure temporary support system shall be used. S3. Concrete Arched Water-Intercepting Skeleton Slope Protection Construction: Excavate and trim the foundation trench, install it using different formwork, pour concrete in layers and sections from bottom to top, and vibrate it. Concrete is poured in sequence, along with the subsequent platform and intercepting ditch. Parameters for the concrete arched water-intercepting skeleton are set, and ecological slope protection measures are implemented, including the installation of ecological holes, ecological bag slope protection, native plant buffer zones, grass seed spraying, and shrub planting. S4. Concrete retaining wall construction: Use concrete gravity retaining wall support and backfill the embankment retaining wall. For retaining walls of different heights, adopt a layered pouring method. Use PFF integral filter layer construction, use concrete spraying to reinforce weak soil layers, and set expansion joints in the retaining wall and perform caulking treatment. S5. Concrete footing wall construction: Determine the footing wall size and use concrete gravity retaining wall support, carry out foundation excavation and formwork installation, install drainage pipes according to design requirements, pour concrete in multiple layers according to the height of the retaining wall and vibrate it. After the retaining wall foundation is poured, immediately backfill the foundation pit and compact it in layers.

[0022] Specifically, in S1: Pre-emptively identify potential hazards such as landslides and collapses to ensure construction safety; divide construction sections to facilitate construction organization and management, and rationally schedule construction progress; roughly stake out and lay out red lines to provide a benchmark for subsequent precise stakeout and positioning; protect topsoil resources for subsequent greening and backfilling to promote ecological restoration; use drones to accurately capture the topography of complex areas, combine geological data with design simulation optimization plans, accurately arrange bamboo piles and record data to improve support effectiveness and reduce construction risks. In S2: Step-by-step excavation and layered protection: excavate step by step from top to bottom, using platforms for step-by-step protection to control slope deformation; control excavation depth and sequence to prevent slope instability, ensure that the excavation slope and shape meet the design, and ensure construction quality; provide temporary support for high slopes; implement targeted measures and set up drainage ditches to reduce the impact on the surrounding environment; set up temporary drainage ditches to prevent water erosion on the slopes. In S3: excavation and finishing of the foundation trench ensure accurate installation position and depth, enhance skeleton stability, and fully compact the concrete; sequential pouring ensures overall structural integrity and continuity; ecological slope protection measures promote vegetation recovery through the installation of ecological holes and ecological bags, stabilize the soil, and reduce soil erosion. In S4: gravity retaining wall support relies on its own weight to resist soil pressure and provide stable support for the embankment and slope; backfill soil in the embankment retaining wall increases soil pressure behind the retaining wall and improves stability; layered pouring method, based on the height of the retaining wall, ensures concrete density and reduces cracks; PFF filter layer construction for drainage and anti-seepage, reduces groundwater erosion, prevents soil particle loss, and extends the service life of the retaining wall; sprayed concrete reinforces weak soil layers and improves the foundation bearing capacity. In S5: determine the size and gravity support to provide stable bottom support for the slope, meet structural requirements, and withstand soil and water pressure; foundation excavation and formwork installation: determine the installation position and depth to ensure that the shape and size meet the design and enhance the stability of the footing wall; install drain pipes for timely drainage; layered pouring and vibration to ensure the concrete is dense and reduce defects.

[0023] Please see the attached Figure 1 The length of the construction section is controlled at 50-80m; the thickness of the topsoil stripping is controlled at 30-50cm; high-resolution images with a resolution of not less than 0.1m are obtained by drone aerial photography; bamboo piles are arranged in the BIM model, their driving position, depth and spacing are simulated, and the distance and angle data from the bamboo piles to the center piles are recorded.

[0024] Specifically, the construction section length is controlled at 50-80m. Reasonable division is conducive to the deployment of teams, equipment, and personnel, improving coordination and efficiency, avoiding chaos and waste, retaining high-quality topsoil, and avoiding waste of resources. Drone aerial photography obtains high-resolution images, clearly recording information such as the site and surrounding terrain, vegetation, and buildings, providing a basis for design planning. The BIM model arranges bamboo piles and records data. The simulated layout identifies pile position conflicts and spacing problems, and optimizes the design.

[0025] Please see the attached Figure 1 The excavation depth of each layer is controlled at 3m to 4m; the new prefabricated steel structure temporary support system includes standardized H-shaped steel columns, channel steel cross braces and diagonal braces, which are connected by bolts, with a column spacing of 1.5m and a cross brace spacing of 2m; for narrow parts of the excavation working face, manual excavation is carried out in conjunction with small mechanical equipment, and micro piles are set up for protection; for rocks of different strengths, controlled blasting technology is used for excavation, and sprayed anchor support is used for protection; for vibration and noise sensitive areas, vibration isolation trenches are set up for protection; the width of the temporary drainage ditch is 300mm, and circular drainage ditches are set up at the top and foot of the slope on the hillside. Single-sided or double-sided drainage ditches are set up on the on-site roads and branch roads according to different requirements, and the slope of the ditch bottom is 2%-8%.

[0026] Specifically, the excavation depth is controlled in layers of 3m-4m, which is convenient for construction operations and earthwork transportation, and can effectively reduce the risk of slope instability. The new prefabricated steel structure temporary support system adopts standardized component bolt connection, which can be quickly erected and disassembled. The design of 1.5m column spacing and 2m cross brace spacing can provide efficient support and ensure the structural safety of the excavation area. In the narrow part of the excavation working face, manual operation with small machinery can flexibly cope with complex environments. Micro-pile protection further enhances the stability of narrow parts and prevents collapse. Controlled blasting technology is used for rocks of different strengths. Accurately control the blasting effect to reduce damage to the surrounding rock mass, and follow up with shotcrete support in a timely manner to effectively fix the rock and prevent it from loosening and sliding. Set up vibration isolation trenches in vibration and noise sensitive areas to effectively block the spread of blasting vibration and noise, and reduce the impact on the surrounding environment and facilities. Plan the drainage system, with a temporary drainage ditch width of 300mm. Set up circular drainage ditches at the top and foot of the slope on the hillside. Set up single-sided or double-sided drainage ditches on the on-site roads as needed. The ditch bottom slope of 2%-8% ensures smooth drainage, avoids water accumulation that damages the construction area and the surrounding environment, and ensures safe and orderly progress of construction. Please see the attached Figure 1 The narrow parts of the excavation working face are turned over by excavators; the slope of the temporary slope is controlled at 1:1, and the excavation is first carried out to 50cm~100cm away from the designed slope line, and then the slope is repaired mechanically and manually; the strongly weathered rock with a strength of 5MPa~30MPa is excavated in layers by rock drilling machinery combined with excavators.

[0027] Specifically, in special areas with narrow excavation working surfaces, excavators are used for slag turning operations, which can flexibly adapt to limited space, efficiently clean up debris, and ensure the continuity and smoothness of excavation construction in narrow areas; first, mechanical excavation is carried out to a reserved position 50cm-100cm away from the designed slope line, and then the slope is finely repaired by machinery in combination with manual labor, which fully utilizes the advantages of rapid mechanical excavation and the characteristics of precise manual repair; for strongly weathered rocks with a strength of 5MPa-30MPa, rock drills and excavators are used for layered excavation. Rock drills can effectively crush rocks, and excavators are responsible for quickly cleaning and transporting gravel. The layered excavation method can gradually and orderly peel off the rock layers, reduce the difficulty and safety risks of excavation, and ensure safe and efficient progress of construction.

[0028] Please see the attached Figure 1 The concrete arch water-cutting frame adopts C30 concrete; in the middle of the slope, the main frame thickness is 0.6m, the arch frame thickness is 0.4m, and the net spacing is 3m; at the top and bottom of the slope, the main frame thickness is 0.5m, the arch frame thickness is 0.35m, and the net spacing is 3.5m; an expansion joint with a width of 0.02m is set every 3-5 arches, filled with asphalt hemp tendons, and a step is set every 80m; the diameter of the ecological hole is 10-15cm, and the hole spacing is 0.5-0.8m; the backfill planting soil in the frame is mixed with 30% humus soil and 20% organic fertilizer; the ecological bag is made of degradable polypropylene fiber material, filled with nutrient soil and grass seeds; a 2m wide native plant buffer zone is set at the foot of the slope; the grass seeds and fertilizers are mixed evenly and then mechanically sprayed, and covered with non-woven fabric after spraying; the shrubs are Sophora japonica, which are laid out at a spacing of 0.6m×0.6m, with 2 plants planted in each hole, and watered for health after planting.

[0029] Specifically, the arched water-cutting framework is cast using C30 concrete. Its high strength provides solid support for the slope against water erosion and soil pressure, ensuring reliable slope protection. To account for differential loads in different slope sections, the central main and arch frameworks are thickened and the net spacing is narrowed to enhance structural strength and effectively channel water flow. The framework thickness is appropriately reduced and the net spacing is increased at the top and bottom, optimizing material utilization while ensuring protective effectiveness. Expansion joints filled with asphalt rebar effectively buffer concrete deformation stresses caused by temperature fluctuations and foundation settlement, preventing structural cracking and extending the framework's service life. Steps are installed every 80 meters to provide safe and convenient access for slope inspections and maintenance, improving management efficiency. The optimal diameter and spacing of the ecological holes ensures sufficient space for vegetation growth while maintaining the framework's structural stability and enhancing the slope's ecological protection capabilities. The framework is backfilled with planting soil mixed with humus and organic fertilizer to improve soil structure and nutrient content, creating a high-quality environment for vegetation growth. Eco-bags are made of biodegradable materials and filled with nutrient soil and grass seeds, achieving both initial protection and long-term ecological restoration without any pollution. A buffer zone of native plants is established at the foot of the slope to mitigate runoff, reduce soil erosion, build a stable ecosystem, and enhance slope stability. Grass seeds and fertilizers are mechanically sprayed and covered with non-woven fabric to ensure even distribution, increasing vegetation coverage and survival rates. Dense planting of shrubs, using the well-developed root system of Amorpha fruticosa, quickly stabilizes the soil and protects the slope, forming a vegetation community. Watering ensures survival, achieving the coordinated development of slope ecology and protection.

[0030] Please see the attached Figure 1 For retaining walls with a height of less than or equal to 3m, steel molds are used for one-time layer casting, and the thickness of each layer does not exceed 50cm; for retaining walls greater than 3m, steel molds are used for multiple layer casting, and the height of each layer does not exceed 3m; the PFF integral filter layer is laid vertically along the back slope of the wall, and the two pieces are fixed with U-shaped anchor nails or cement steel nails at the joints, with the spacing between the fixing nails not exceeding 5.0m. The overlapped parts between the pieces are sealed with adhesive tape, and the upper port of the composite filter layer is temporarily wrapped and sealed with geotextile or plastic film; when spraying concrete for reinforcement, first use the water-cement ratio Lubricate the hopper and feed pipeline of the sprayer with 1:2 pure cement slurry, with an air pressure of 0.9 MPa and a water pressure of 0.4 MPa. Adjust the spraying speed and control the amount of accelerator added. The spraying operation is carried out in sections and pieces from bottom to top. Adjust the distance and angle between the spray gun and the sprayed surface. The distance between the nozzle and the sprayed surface is 0.6 to 1.0 m, and the angle between the nozzle and the vertical line of the sprayed surface is 10 to 15 degrees. Spray in layers with a thickness of 3 to 5 cm. After the spraying construction is completed, seal the joints. The expansion joints are 20 mm wide and plugged with asphalt tendons.

[0031] Specifically, different pouring methods are used for retaining walls of different heights. The steel formwork for retaining walls with a height of ≤3m is poured in layers at one time, and the thickness of each layer is ≤50cm, which can ensure that the concrete is uniform and dense; the steel formwork for retaining walls with a height of >3m is poured in multiple layers, and the height of each layer is ≤3m, which can reduce the temperature difference between the inside and outside of the concrete and prevent cracks; the PFF integral filter layer is laid vertically and fixed with anchor nails (spacing ≤5.0m), the overlap parts between the pieces are bonded and sealed with tape, and the upper port is wrapped and closed, which can effectively drain water and prevent soil loss; when spraying concrete, first lubricate the sprayer hopper and feed pipeline, control the wind pressure and water pressure, adjust the spraying speed and the amount of accelerator added, and spray in sections and pieces from bottom to top, control the distance (0.6~1.0m) and angle (vertical angle 10~15º) between the spray gun and the sprayed surface, spray in layers to control the thickness of the single spray (3~5cm), and seal the joints and plug the expansion joints after construction to ensure the reinforcement effect and structural stability.

[0032] Please see the attached Figure 1 The foot wall is 1.5m high, 0.8m deep and 0.7m thick; when the foundation is excavated, the mechanical excavation is carried out to 30cm from the base and then leveled and compacted; the formwork adopts 1.5m×0.6m standard steel formwork, and combined wooden formwork is used at both ends, and the formwork is erected at one time; φ25mm HRB400 steel bars are embedded in the concrete poured in the upper layer for formwork tensioning, and φ48.3 steel pipes are used as internal supports inside the formwork, which are removed after the concrete is poured and covers the supporting steel pipes; after the formwork is installed, supports are set every 1m horizontally.

[0033] Specifically, the formwork mainly uses 1.5m×0.6m standard steel formwork, which is matched with combined wooden formwork at both ends, and is formed in one step, taking into account both construction efficiency and adaptability to special parts; pre-embedded φ25mmHRB400 steel bars are used for formwork tensioning to enhance the formwork's ability to resist lateral pressure and prevent formwork deformation during pouring; φ48.3 steel pipes are used as internal supports inside the formwork, and are removed after the concrete is poured to cover the supporting steel pipes, ensuring the shape stability of the formwork during the pouring process and facilitating subsequent dismantling operations; after the formwork is installed, supports are set every 1m horizontally to further enhance the overall stability of the formwork system, prevent it from displacement or deformation under the pressure of concrete pouring, and ensure that the foot wall structure size is accurate and the appearance quality meets the standards.

[0034] Please see the attached Figure 1 The drainage pipe is installed at the drainage hole position according to the designed spacing, discharged to the ground at a slope of 4%, and fixed in place with φ10HPB steel bars. The pipe mouth is sealed before concrete pouring.

[0035] Specifically, the drain pipes are installed at precisely the designed spacing corresponding to the positions of the drain holes, which can ensure the accurate discharge of water accumulated inside structures such as slopes and retaining walls; a 4% slope is set to drain to the ground, and gravity can be used to allow water to drain naturally and smoothly, reducing residual water and the risk of erosion of structural materials due to long-term water accumulation, thereby extending the service life of the structure; φ10HPB steel bars are used to fix the position, which can effectively resist the lateral pressure and construction disturbances generated during the concrete pouring process, prevent the drain pipe from shifting and deforming, and ensure the accuracy and reliability of the drainage system; the pipe mouth is sealed before concrete pouring to prevent concrete slurry from entering the pipe during pouring and causing blockage, ensuring smooth drainage of the drain pipe, maintaining the normal operation of the structural drainage function, and providing solid guarantees for the overall quality and safety of the project.

[0036] Please see the attached Figure 1 The concrete footing wall is constructed in three times according to the height of the retaining wall. Each pouring is carried out layer by layer from bottom to top. The thickness of each layer does not exceed 50 cm. The upper layer of concrete is poured before the lower layer of concrete begins to set, and is vibrated with an inserted vibrator. After the retaining wall foundation is poured, the foundation pit is backfilled immediately. During the backfilling process, the concrete is compacted layer by layer, and the compaction degree is not less than 90%.

[0037] Specifically, the concrete footing is constructed in three stages, depending on the height of the retaining wall. Each time, the concrete is poured from bottom to top in layers, with a single layer thickness of ≤50cm. This method effectively controls the accumulation of concrete hydration heat, avoiding cracks caused by excessive temperature differences between the inside and outside due to a single pour of too thick concrete. It also facilitates layered vibration and compaction, ensuring the internal quality of the concrete. The upper layer of concrete must be poured before the initial setting of the lower layer, which ensures a tight bond between the layers, eliminates the hidden dangers of construction cold joints, improves the integrity and strength of the footing, and guarantees its bearing capacity. The use of an inserted vibrator for vibration can fully eliminate bubbles within the concrete, ensure even distribution of aggregates, and fully wrap the cement slurry, further improving the density and durability of the concrete. After the retaining wall foundation is poured, the foundation pit is immediately backfilled and compacted in layers, with a compaction degree of ≥90%. This provides timely lateral constraints for the retaining wall foundation, reduces the risk of foundation settlement and displacement, enhances the stability of the retaining wall, and avoids safety hazards caused by long-term exposure of the foundation pit, ensuring subsequent construction safety and the overall quality of the retaining wall.

[0038] Please see the attached Figure 1 After the concrete is poured, it is cured. After the concrete is poured, the concrete surface should be covered with water for curing after the cement reaches the final setting time. The curing time is not less than 7 days, and the concrete surface should be kept moist during curing.

[0039] Specifically, concrete requires prompt curing after pouring. Once the cement reaches its final setting time, the concrete surface should be immediately covered and watered to maintain moisture, promoting strength growth through continuous hydration. The curing period is strictly set to no less than seven days, during which the concrete surface must remain moist at all times to prevent rapid evaporation of water, which could lead to uneven shrinkage and cracking of the internal structure. This also provides an environment for the cement to fully react, ensuring that performance indicators such as concrete density, impermeability, and durability meet standards, safeguarding the quality of the project structure and its long-term safety.

[0040] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A construction process for railway roadbed slope protection engineering, characterized in that: The following steps are involved: S1. Construction Preparation: Conduct a stability check on the mountain, divide the slope protection project into multiple construction sections, conduct a rough stakeout, lay out the slope redline position, clean the surface within the redline, strip the topsoil and store it separately for subsequent greening backfill. For areas with slopes greater than 45° or geological fracture zones, use drones to obtain high-resolution aerial images, generate a 3D slope model through 3D modeling, import it into the BIM platform, combine geological survey data with design drawings, simulate and optimize the construction plan, accurately arrange bamboo piles, and record relevant data. S2. Excavation of earthwork: Slopes shall be laid out according to the designed slope, excavated step by step from top to bottom, and protected by layers of construction platforms. The excavation depth and sequence of each layer shall be controlled. For slopes with a height of 5m or more, a new type of prefabricated steel structure temporary support system shall be used. S3. Concrete Arched Water-Intercepting Skeleton Slope Protection Construction: Excavate and trim the foundation trench, install it using different formwork, pour concrete in layers and sections from bottom to top, and vibrate it. Concrete is poured in sequence, along with the subsequent platform and intercepting ditch. Parameters for the concrete arched water-intercepting skeleton are set, and ecological slope protection measures are implemented, including the installation of ecological holes, ecological bag slope protection, native plant buffer zones, grass seed spraying, and shrub planting. S4. Concrete retaining wall construction: Use concrete gravity retaining wall support and backfill the embankment retaining wall. For retaining walls of different heights, adopt a layered pouring method. Use PFF integral filter layer construction, use concrete spraying to reinforce weak soil layers, and set expansion joints in the retaining wall and perform caulking treatment. S5. Concrete footing wall construction: Determine the footing wall size and use concrete gravity retaining wall support, carry out foundation excavation and formwork installation, install drainage pipes according to design requirements, pour concrete in multiple layers according to the height of the retaining wall and vibrate it. After the retaining wall foundation is poured, immediately backfill the foundation pit and compact it in layers.

2. A railway roadbed slope protection engineering construction process according to claim 1, characterized in that: The length of the construction section is controlled at 50-80m; the thickness of the topsoil stripping is controlled at 30-50cm; high-resolution images with a resolution of not less than 0.1m are obtained by drone aerial photography; bamboo piles are arranged in the BIM model, their driving position, depth and spacing are simulated, and the distance and angle data from the bamboo piles to the center piles are recorded.

3. A railway roadbed slope protection engineering construction process according to claim 1, characterized in that: The excavation depth of each layer is controlled at 3m to 4m; the new prefabricated steel structure temporary support system includes standardized H-shaped steel columns, channel steel cross braces and diagonal braces, which are connected by bolts, with a column spacing of 1.5m and a cross brace spacing of 2m; for narrow areas of the excavation working face, manual excavation is carried out in conjunction with small mechanical equipment, and micro-piles are set up for protection; for rocks of different strengths, controlled blasting technology is used for excavation, and sprayed anchor support is used for protection; for vibration and noise sensitive areas, vibration isolation trenches are set up for protection; the width of the temporary drainage ditch is 300mm, and circular drainage ditches are set up at the top and foot of the slope on the hillside. Single-sided or double-sided drainage ditches are set up on the on-site roads and branch roads according to different requirements, and the slope of the ditch bottom is 2%-8%.

4. A railway roadbed slope protection engineering construction process according to claim 1, characterized in that: The narrow parts of the excavation working face are turned over by excavators; the slope of the temporary slope is controlled at 1:1, and the excavation is first carried out to 50cm to 100cm away from the designed slope line, and then the slope is repaired mechanically and manually; the strongly weathered rock with a strength of 5MPa to 30MPa is excavated in layers using rock drilling machinery in combination with excavators.

5. The railway roadbed slope protection engineering construction process according to claim 1, characterized in that: The concrete arch water-cutting frame adopts C30 concrete; in the middle of the slope, the main frame thickness is 0.6m, the arch frame thickness is 0.4m, and the net spacing is 3m; at the top and bottom of the slope, the main frame thickness is 0.5m, the arch frame thickness is 0.35m, and the net spacing is 3.5m; an expansion joint with a width of 0.02m is set every 3-5 arches, filled with asphalt hemp tendons, and a step is set every 80m; the diameter of the ecological hole is 10-15cm, and the hole spacing is 0.5-0.8m; the backfill planting soil in the frame is mixed with 30% humus soil and 20% organic fertilizer; the ecological bag is made of degradable polypropylene fiber material, filled with nutrient soil and grass seeds; a 2m wide native plant buffer zone is set at the foot of the slope; the grass seeds and fertilizers are mixed evenly and then mechanically sprayed, and then covered with non-woven fabric; the shrubs are Robinia pseudoacacia, which are laid out at a spacing of 0.6m×0.6m, with 2 plants planted in each hole, and watered for health after planting.

6. A railway roadbed slope protection engineering construction process according to claim 1, characterized in that: For retaining walls with a height of less than or equal to 3m, steel molds are used for one-time layer casting, and the thickness of each layer does not exceed 50cm; for retaining walls with a height of more than 3m, steel molds are used for multiple layer casting, and the height of each layer does not exceed 3m; the PFF integral filter layer is laid vertically along the back slope of the wall, and the two pieces are fixed with U-shaped anchor nails or cement steel nails at the joints, with the spacing between the fixing nails not exceeding 5.0m. The overlapped parts between the pieces are sealed with tape, and the upper port of the composite filter layer is temporarily wrapped and sealed with geotextile or plastic film; when spraying concrete for reinforcement, first use a water-cement ratio of Lubricate the hopper and feed pipeline of the sprayer with 1:2 clean cement slurry, with an air pressure of 0.9 MPa and a water pressure of 0.4 MPa. Adjust the spraying speed and control the amount of accelerator added. Perform the spraying operation in sections and pieces from bottom to top. Adjust the distance and angle between the spray gun and the sprayed surface. The distance between the nozzle and the sprayed surface should be 0.6-1.0 m, and the angle between the nozzle and the vertical line of the sprayed surface should be 10-15 degrees. Spray in layers with a thickness of 3-5 cm. After the spraying construction is completed, seal the joints. The expansion joints should be 20 mm wide and plugged with asphalt tendons.

7. The railway roadbed slope protection engineering construction process according to claim 1, characterized in that: The foot wall is 1.5m high, 0.8m deep and 0.7m thick; when the foundation is excavated, it is mechanically excavated to 30cm from the base and then leveled and compacted; the formwork uses a 1.5m×0.6m standard steel formwork, and combined wooden formwork is used at both ends, and the formwork is erected at one time; φ25mm HRB400 steel bars are embedded in the concrete poured in the upper layer for formwork tensioning, and φ48.3 steel pipes are used inside the formwork as internal supports, which are removed after the concrete covers the supporting steel pipes during pouring; after the formwork is installed, supports are set every 1m horizontally.

8. The railway roadbed slope protection engineering construction process according to claim 1 is characterized in that: The drainage pipe is installed at the position of the drainage hole according to the designed spacing, discharged to the ground at a slope of 4%, fixed in position with φ10HPB steel bars, and the pipe opening is sealed before concrete pouring.

9. The railway roadbed slope protection engineering construction process according to claim 1, characterized in that: The concrete footing wall is constructed in three times according to the height of the retaining wall. Each pouring is carried out in layers from bottom to top, and the thickness of each layer does not exceed 50 cm. The upper layer of concrete is poured before the lower layer of concrete begins to set, and is vibrated with an inserted vibrator. After the retaining wall foundation is poured, the foundation pit is backfilled immediately, and the backfilling process is carried out in layers, with a compaction degree of not less than 90%.

10. The railway roadbed slope protection engineering construction process according to claim 1, characterized in that: After the concrete is poured, it is cured. After the concrete is poured and the cement reaches the final setting time, the concrete surface should be covered with water for curing. The curing time is not less than 7 days, and the concrete surface should be kept moist during curing.

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