Precast concrete channel type separation belt structure of urban road in collapsible loess area

Abstract

The utility model relates to the field of city road accessory facilities especially, and more particularly to city road prefabricated concrete groove type separation zone structure in collapsible loess area, its characterized in that, separation zone structure contains two groups of symmetrical arrangement L type prefabricated concrete groove board (1), and L type prefabricated concrete groove board (1) is L type C35 anti-sulfur prefabricated concrete groove board, and L type prefabricated concrete groove board (1) bottom is located the upper position of the bottom surface of roadbed (7), and two groups of symmetrical arrangement L type prefabricated concrete groove board (1) between are arranged with bottom lime soil closing layer (2), and bottom lime soil closing layer (2) top is arranged with biochar layer (4), and biochar layer (4) top is arranged with cultivated soil layer (5). Advantageous effect: waterproof performance promotion, and the road section green belt permeation of adopting this structure greatly reduces, and the water content of roadbed is stable, and effectively prevent the disease of collapsible loess.

Description

Technical Field

[0001] This utility model relates to the field of urban road ancillary facilities, and more particularly to the precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas. Background Technology

[0002] Collapsible loess possesses high strength in its natural state, but its structure rapidly deteriorates upon contact with water, leading to significant subsidence. Subsidence of collapsible loess foundations easily triggers a series of engineering problems, such as uneven foundation settlement and slope instability. Observations of several completed urban roads in Lanzhou New Area revealed that the main defects include subsidence of the roadbed and pavement, deformation of curb stones, cracking of the pavement, and landslides and cavities at certain locations. These pose significant safety hazards to vehicles and greatly increase maintenance costs. Our investigation found that these defects are primarily concentrated on lanes near the median strip.

[0003] In the drainage design of green belts, a two-layer geotextile with a membrane is typically used, laid from the top of the curbstone down to 0.5 meters below the planting soil. However, due to substandard construction quality, the geotextile is sometimes laid too low, or the overlaps are not properly treated, or the geotextile is damaged when planting heavy trees. This results in the geotextile failing to effectively contain water within the green belt. When the green belt is watered, the water seeps through the soil and then penetrates from the bottom of the curbstone and adjacent joints into the pavement structure and below, causing roadbed and pavement defects and further exacerbating their development.

[0004] In collapsible loess areas, the strength of collapsible loess within the roadbed area decreases under the influence of water. To meet the strength requirements of the CBR value, it is usually necessary to carry out roadbed lime-soil replacement treatment to eliminate the collapsibility of the collapsible loess, thereby ensuring the strength and service requirements of the roadbed.

[0005] Traditional construction methods are highly dependent on construction quality: the two-layer geotextile and one-layer geomembrane require manual laying, making them susceptible to damage from planting operations (such as tree transplantation), and the sealing of the overlaps is difficult to guarantee. Furthermore, geotextiles have a short lifespan in the acidic and alkaline environment of loess, typically showing a significant decline in impermeability after 5-8 years. Moreover, existing geotextiles only cover 0.5 meters below the planting soil, and deep infiltration can still lead to roadbed defects. Summary of the Invention

[0006] The purpose of this utility model is to provide a precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas with better performance. The specific purpose is explained in the several substantive technical effects in the specific implementation section.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas is characterized in that the median strip structure includes two sets of symmetrically arranged L-shaped precast concrete trough slabs 1. The L-shaped precast concrete trough slabs 1 are L-shaped C35 anti-sulfurization precast concrete trough slabs, and the bottom of the L-shaped precast concrete trough slabs 1 is located at the upper part of the bottom surface of the roadbed 7. A bottom lime-soil sealing layer 2 is arranged between the two sets of symmetrically arranged L-shaped precast concrete trough slabs 1, a biochar layer 4 is arranged above the bottom lime-soil sealing layer 2, and a topsoil layer 5 is arranged above the biochar layer 4.

[0008] A further technical solution of this utility model is that the roadbed 7 forms a trough-shaped separation zone with the L-shaped precast concrete trough slabs 1 on both sides and the bottom lime-soil sealing layer 2 at the bottom, which is used to prevent water seepage from the green belt.

[0009] A further technical solution of this utility model is characterized in that the ends of the L-shaped precast concrete trough slab 1 are connected to each other by tongue and groove joints.

[0010] A further technical solution of this utility model is that the L-shaped precast concrete trough slab 1 is made of C35 sulfate-resistant concrete, with a 28-day compressive strength ≥35MPa, an impermeability grade of P8, and a freeze-thaw resistance grade of F200. L-shaped precast concrete trough slab 1 dimensions: thickness 200mm, height 1500-1800mm, length 6000mm.

[0011] A further technical solution of this utility model is that the L-shaped precast concrete trough slab 1 is constructed as follows: the vertical section is embedded 500-600mm below the bottom surface of the roadbed, forming a physical barrier with the lime-soil replacement layer; the horizontal section of the L-shaped precast concrete trough slab 1 is 500mm wide and extends into the interior of the pavement structure layer 6, which facilitates the construction of the pavement structure layer and ensures the stability of the L-shaped precast concrete trough slab.

[0012] A further technical solution of this utility model is that a 200-300mm thick 3:7 lime-soil sealing layer (compaction degree ≥95%) is laid continuously along the longitudinal direction of the dividing strip to form a trough-shaped structure bottom.

[0013] A further technical solution of this utility model is that a 50mm×50mm tongue and groove joint is reserved at the end of the L-shaped precast concrete trough plate 1, and the joint is filled with polyurethane sealant to form a double waterproof barrier.

[0014] A further technical solution of this utility model is that the biochar layer has a thickness of 200-300mm, a particle size of 3-5mm, an organic matter content of ≥60%, and a water retention rate of ≥40%, thus having both water retention and soil improvement functions. Topsoil layer: thickness ≥500mm, organic matter content ≥3%, pH value 6.5~7.5, meeting the growth needs of tree and shrub roots.

[0015] The present invention, which adopts the above technical solution, has the following beneficial effects compared with the prior art: improved waterproof performance, greatly reduced infiltration of green belts in road sections using this structure, stable roadbed moisture content, and effective prevention of diseases of collapsible loess.

[0016] Economic optimization, reducing total life cycle cost by 35%: Reduced maintenance frequency (traditional solutions require maintenance every 3 years, while this solution extends the cycle to more than 15 years), reducing maintenance costs.

[0017] It has significant environmental benefits. The biochar layer can fix 2.5 kg / m² of carbon and reduce the use of chemical fertilizers by 40%, which meets the requirements for sponge city construction.

[0018] Biochar layers increase soil water holding capacity by 35% and plant survival rate to 85%. Attached Figure Description

[0019] To further illustrate this utility model, the following description is provided in conjunction with the accompanying drawings: Figure 1 Schematic diagram of the utility model; Figure 2 Side view of the utility model; The components include: 1. L-shaped precast concrete trough slab; 2. bottom lime-soil sealing layer; 3. tongue and groove joint; 4. biochar layer; 5. topsoil layer; 6. pavement structure layer; 7. roadbed. Detailed Implementation

[0020] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0021] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0022] This patent provides multiple parallel solutions; the different descriptions represent improved or parallel solutions based on a basic solution. Each solution has its own unique characteristics. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other. Fixing methods not described herein can be any type of fixing, such as threaded fixing, bolt fixing, or adhesive bonding.

[0023] Example 1: Combining Figure 1 and Figure 2A precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas is characterized by comprising two sets of symmetrically arranged L-shaped precast concrete trough slabs 1. The L-shaped precast concrete trough slabs 1 are L-shaped C35 anti-sulfurization precast concrete trough slabs, with their bottoms located above the bottom surface of the roadbed 7. A bottom lime-soil sealing layer 2 is arranged between the two sets of symmetrically arranged L-shaped precast concrete trough slabs 1, a biochar layer 4 is arranged above the bottom lime-soil sealing layer 2, and a topsoil layer 5 is arranged above the biochar layer 4. The substantive technical effects and implementation process of this technical solution, i.e., its basic functions, are as follows: The commonly used 50-100cm segment curb stones were further optimized by using L-shaped C35 sulfide-resistant precast concrete trough slabs. The bottom of these slabs is located at the upper part of the roadbed surface. L-shaped precast concrete trough slabs on both sides form a trough-shaped separation zone with the underlying lime-soil to prevent water seepage into the green belt. The ends of the L-shaped precast concrete trough slabs are connected by tongue-and-groove joints. To ensure suitable growing conditions for the plants, biochar is placed on top of the lime-soil to retain water and improve the plant's environment. Topsoil is then backfilled on top of the biochar.

[0024] Precast concrete channel slabs form a rigid waterproof structure that creates a physical barrier, replacing traditional flexible geotextiles and avoiding construction damage and aging issues. The bottom of the channel slab is embedded below the subgrade surface, cutting off deep seepage paths.

[0025] The L-shaped structure simultaneously serves the functions of waterproofing, partitioning, and load transfer, reducing the number of auxiliary structures.

[0026] The combination of biochar layer and topsoil optimizes the plant growth microenvironment by providing water retention, aeration, and nutrients.

[0027] Modular construction and 6m long trough slabs reduce the number of joints (83% less than traditional 50-100cm segments), lowering the risk of leakage. Precast components are factory-produced, ensuring quality control and increasing construction efficiency by over 60%.

[0028] Excavation of foundation trench: Excavate the foundation trench according to the design elevation, and compact the bottom of the trench to a compaction degree of ≥93%. Use a laser level to control the flatness (error ≤±5mm).

[0029] Lime-soil replacement: Fill with a 3:7 bottom lime-soil sealing layer of 200mm, compact it to a compaction degree of ≥95%, and lay a 20mm thick M10 cement mortar leveling layer on the top surface.

[0030] Slot plate installation: Use special clamps for hoisting, and the tongue and groove joint error is ≤3mm.

[0031] Subgrade construction: Backfill the outside of the trench with impermeable lime-soil and compact it in layers (each layer is 15 cm thick).

[0032] Road surface structure layer construction: Subbase, base course, and surface course are constructed sequentially on the outside of the trough slab.

[0033] Ecological layer laying: lay biochar layer (20 cm) and topsoil layer (50 cm) in sequence, and compact them to the design elevation.

[0034] Planting and maintaining plants.

[0035] A precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas is characterized by comprising: L-shaped precast concrete trough slabs 1 symmetrically arranged on both sides, a bottom lime-soil sealing layer 2, a tongue-and-groove joint 3, a biochar layer 4, and a topsoil layer 5; the L-shaped precast concrete trough slabs 1 are 200mm thick and 1500-1800mm high, with the bottom embedded above the top surface of the roadbed, and the horizontal section extending 500mm to the pavement structure layer; the tongue-and-groove joints of adjacent trough slabs are filled with polyurethane sealant at the outer end of the joints; the biochar layer 4 is 200mm thick, located on top of the lime-soil sealing layer 2, and covered with the topsoil layer 5.

[0036] This utility model solves the problem of water seepage in green belts in collapsible loess areas by combining a rigid precast trough slab bottom roadbed treatment system. At the same time, it optimizes the plant growth environment through a biochar layer. It has the advantages of convenient construction, high durability, and eco-friendliness, and is suitable for new construction and reconstruction of urban roads in collapsible loess areas.

[0037] Example 2: As a further improvement, parallel, or optional independent solution, the roadbed 7 forms a trough-shaped separation zone with the bottom soil through the L-shaped precast concrete trough slabs 1 on both sides, to prevent water seepage from the green belt. The substantive technical effect and implementation process of this technical solution, i.e., its basic function, is as follows: to form an effective physical barrier.

[0038] Example 3: As a further improvement, parallel, or optional independent solution, the L-shaped precast concrete trough slab 1 is characterized in that the ends are connected by tongue and groove joints. The substantive technical effect and implementation process of this technical solution, i.e., its basic function, are as follows: thus, it facilitates sealing.

[0039] Example 4: As a further improvement, parallel, or optional independent solution, the L-shaped precast concrete trough slab 1 is made of C35 sulfate-resistant concrete, with a 28-day compressive strength ≥35MPa, impermeability grade P8, and frost resistance grade F200. L-shaped precast concrete trough slab 1 dimensions: thickness 200mm, height 1500-1800mm, length 6000mm.

[0040] Example 5: As a further improvement, parallel, or optional independent solution, the L-shaped precast concrete trough slab 1 is constructed as follows: the vertical section is embedded 500-600mm below the bottom surface of the roadbed, forming a physical barrier with the lime-soil replacement layer; the horizontal section of the L-shaped precast concrete trough slab 1 is 500mm wide and extends into the interior of the pavement structure, facilitating the construction of the pavement structure layer and ensuring the stability of the L-shaped precast concrete trough slab.

[0041] Example 6: As a further improvement, parallel or alternative independent solution, the bottom lime-soil sealing layer (2) is 200-300mm thick 3:7 lime-soil (compaction degree ≥95%), which is laid continuously along the longitudinal direction of the dividing strip to form the bottom of the trough structure.

[0042] Example 7: As a further improvement, parallel, or optional independent solution, a 50mm×50mm tongue and groove joint is reserved at the end of the L-shaped precast concrete trough slab 1, and the joint is filled with polyurethane sealant to form a double waterproof barrier.

[0043] Example 8: As a further improvement, parallel, or optional independent solution, the biochar layer has the following characteristics: thickness 200-300 mm, particle size 3-5 mm, organic matter content ≥60%, water retention rate ≥40%, and combines water retention and soil improvement functions. Topsoil layer: thickness ≥500mm, organic matter content ≥3%, pH value 6.5~7.5, meeting the growth needs of tree and shrub roots.

[0044] Innovatively, each of the above effects exists independently, yet a single structure can be used to combine the results.

[0045] It should be noted that the multiple modules in this patent are an integration of existing technology modules and do not involve any new modules. Even if some modules use programs, those programs are undoubtedly known programs.

[0046] It should be noted that the multiple solutions provided in this patent include their own basic solutions, which are independent of each other and do not restrict each other. However, they can also be combined with each other without conflict to achieve multiple effects.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims.

Claims

1. A precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas, characterized in that, The partition structure includes two sets of symmetrically arranged L-shaped precast concrete troughs (1). The L-shaped precast concrete troughs (1) are L-shaped C35 anti-sulfurization precast concrete troughs. The bottom of the L-shaped precast concrete troughs (1) is located at the upper part of the bottom surface of the roadbed (7). A bottom lime-soil sealing layer (2) is arranged between the two sets of symmetrically arranged L-shaped precast concrete troughs (1). A biochar layer (4) is arranged above the bottom lime-soil sealing layer (2). A topsoil layer (5) is arranged above the biochar layer (4).

2. The precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas as described in claim 1, characterized in that, The L-shaped precast concrete trough slab (1) at the top of the roadbed (7) and the bottom lime-soil sealing layer (2) at the bottom form a trough-shaped separation zone to prevent water seepage into the green belt.

3. The precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas as described in claim 1, characterized in that, The ends of the L-shaped precast concrete trough slab (1) are connected by tongue and groove joints.

4. The precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas as described in claim 1, characterized in that, L-shaped precast concrete trough slab (1) Material: C35 sulfate-resistant concrete, 28-day compressive strength ≥35MPa, impermeability grade P8, frost resistance grade F200; L-shaped precast concrete trough slab (1) Dimensions: Thickness 200mm, Height 1500-1800mm, Length 6000mm.

5. The precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas as described in claim 4, characterized in that, L-shaped precast concrete trough (1) structure: The vertical section is embedded 500-600mm below the bottom surface of the roadbed, forming a physical barrier with the lime-soil replacement layer; the horizontal section of the L-shaped precast concrete trough (1) is 500mm wide and extends into the interior of the pavement structure, which facilitates the construction of the pavement structure layer and ensures the stability of the L-shaped precast concrete trough.

6. The precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas as described in claim 1, characterized in that, Bottom lime-soil sealing layer (2): 200-300mm thick 3:7 lime-soil with a compaction degree ≥95%, continuously laid along the longitudinal direction of the dividing strip to form the bottom of the trough structure.

7. The precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas as described in claim 3, characterized in that, The ends of the L-shaped precast concrete trough slab (1) are reserved with a 50mm×50mm tongue and groove joint, and the joint is filled with polyurethane sealant to form a double waterproof barrier.

8. The precast concrete trough-shaped median strip structure for urban roads in collapsible loess areas as described in claim 3, characterized in that, Biochar layer (4): 200-300 mm thick, 3-5 mm in particle size, ≥60% organic matter content, ≥40% water retention rate, with both water retention and soil improvement functions; Topsoil layer (5): thickness ≥ 500 mm, organic matter content ≥ 3%, pH value 6.5~7.5, meeting the growth needs of tree and shrub roots.

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