A frost heave and differential settlement control structure suitable for culvert sections in cold regions

Abstract

This utility model relates to the field of road engineering technology and discloses a frost heave and differential settlement control structure suitable for culvert sections in cold regions. The structure, from top to bottom, includes a roadbed, a fill matrix, a stepped aggregate layer, a stepped high-strength foamed concrete layer, and a culvert. A main drainage pipe is inclinedly arranged in the aggregate layer, and lateral drainage pipes are provided on both sides of the roadbed slopes to drain moisture from the roadbed. The high-strength foamed concrete layer is laid above and on both sides of the culvert, providing good thermal insulation to address freezing issues exacerbated by wind tunnel effects, and buffering the frost heave force of the surrounding soil to prevent direct frost heave force from causing compression damage to the culvert structure. This structure forms a multi-level stiffness transition from flexible to semi-rigid along the culvert transition section of the roadbed, reducing differential settlement and misalignment risks at the connection between the culvert and the roadbed, improving the overall stability of the roadbed and driving safety. The overall structure is reliable, easy to construct, and suitable for widespread application in cold regions.

Description

Technical Field

[0001] This utility model belongs to the field of road engineering technology, and in particular relates to a frost heave and differential settlement control structure suitable for culvert sections in cold regions. Background Technology

[0002] Culverts are typically located below the roadbed and are important ancillary structures of roads. They are mainly used for drainage along the road, crossing low-lying areas or valleys, and providing passage for pedestrians and small vehicles. In highway construction projects, culverts account for more than half of the total number of bridges and culverts, playing a vital role in ensuring road continuity and smooth drainage. Culverts are mostly made of precast or cast-in-place concrete structures, which have high overall rigidity.

[0003] In cold regions, roadbeds are often affected by frost heave and thaw settlement, which can easily lead to uneven deformation. Culverts, due to their significantly greater stiffness than the embankment on both sides, are prone to large differential settlement between themselves and the surrounding flexible roadbed under long-term vehicle loads. This can cause road surface misalignment, cracking, and vehicle bouncing, seriously affecting road performance and driving safety.

[0004] The passage formed by the culvert body is prone to triggering the "wind tunnel effect," which significantly changes the freezing mode of the soil near the culvert. This causes the soil in general road sections to freeze in two or even multiple directions, thereby aggravating the freezing depth and range of the local soil. As a result, the problems of frost heave and thaw settlement caused by this are more serious, and it is easy to cause uneven deformation and cracks in the roadbed of the culvert section.

[0005] Existing engineering measures mostly focus on mitigating single problems. For example, laying insulation materials, replacing with coarse-grained soil, or setting up drainage ditches above or on both sides of culverts are mainly aimed at reducing moisture content and freezing intensity, thereby alleviating frost heave in culvert sections to some extent. However, they fail to address the risk of differential settlement caused by abrupt changes in stiffness between the culvert and the surrounding flexible subgrade. While methods such as thickening the transition layer or reinforcing the filling between the culvert and the subgrade can reduce the differential settlement of frost heave and differential settlement control structures suitable for culvert sections in cold regions, they can improve the rigid-flexible transition of culverts to some extent. However, they usually fail to fully consider the multidirectional freezing and frost heave force transmission characteristics caused by wind tunnel effects in culvert sections. Therefore, there is an urgent need to propose a systematic structure suitable for culvert transition sections in cold regions that can take into account both frost heave prevention and a coordinated rigid-flexible transition. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a frost heave prevention and differential settlement control structure suitable for culvert sections in cold regions. This structure can alleviate the frost heave effect of culvert sections and control the differential settlement between the culvert and the roadbed transition section, thereby improving traffic safety in the transition section.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A frost heave and differential settlement control structure suitable for culvert sections in cold regions includes, from top to bottom: a roadbed, a fill base, an inverted terrace structure graded aggregate layer, an inverted terrace high-strength foamed concrete layer, and a culvert. The top of the inverted terrace structure graded aggregate layer is equipped with a main water collection pipe, the side slopes of the roadbed are equipped with lateral drainage pipes, and the toe of the slopes on both sides of the roadbed is equipped with drainage ditches.

[0009] Furthermore, the culvert is provided with an inverted stepped high-strength foamed concrete layer on its top and sides. The two sides of the inverted stepped high-strength foamed concrete layer are stepped, and the height-to-width ratio of the two steps on both sides of the inverted stepped high-strength foamed concrete layer is 1:(1~1.5). The width of each step is 0.5m~2m. The height from the top of the inverted stepped high-strength foamed concrete layer to the top of the culvert is ≥0.5m. It has sufficient strength to support the superstructure and has a low thermal conductivity, which can effectively delay the freezing of the soil and form a functional zone for heat preservation, frost heave prevention and buffering the transmission of frost heave force.

[0010] Furthermore, a frost heave and differential settlement control structure suitable for culvert sections in cold regions is provided above and on both sides of the high-strength foamed concrete layer of the inverted terrace structure. The inverted terrace structure graded aggregate layer has a thickness of 0.5m to 1m and the two sides of the inverted terrace structure graded aggregate layer are stepped. The height-to-width ratio of the steps of the high-strength foamed concrete layer of the inverted terrace is 1:(1 to 1.5), and the width of each step is 0.5m to 2m. This graded aggregate layer has good water conductivity and guides the water in the upper part of the roadbed into the drainage pipe through infiltration.

[0011] Furthermore, the main water collection pipe (4) is laid obliquely in the inverted terrace structure graded aggregate layer (3). The main water collection pipe (4) is a permeable pipe with an inclination angle of 5° to 10°. The main water collection pipe (4) is arranged at intervals of 3m to 5m along the width direction (longitudinal direction) of the culvert. It can be optimized and adjusted according to local geological conditions, hydrology and drainage needs to ensure that the roadbed of the culvert section has good drainage capacity.

[0012] Furthermore, the main water collection pipe is wrapped with two layers. The outermost layer is a metal reinforcing cage for support and protection. The upper part of the second layer is a one-way permeable layer to guide water from the outside to the inside into the drainage pipe, while preventing soil particles from entering the drainage pipe and causing blockage. The lower part of the second layer is an impermeable membrane to prevent water from leaking from the bottom of the drainage pipe.

[0013] Furthermore, lateral drainage pipes are installed on both sides of the roadbed slope. The lateral drainage pipes are corrosion-resistant and impermeable pipes. One end of the lateral drainage pipe is connected to the main water collection pipe, and the other end is connected to the drainage ditch at the toe of the roadbed slope, so as to discharge the water collected by the main water collection pipe into the drainage ditch.

[0014] Furthermore, the filling substrate (2), the inverted terrace structure graded aggregate layer (3), the inverted terrace high-strength foamed concrete layer (5), and the culvert (6) form a multi-layered stiffness gradient transition structure from flexible, semi-flexible to semi-rigid along the culvert transition section roadbed. This reduces the uneven settlement and misalignment caused by stiffness differences at the connection between the culvert and the roadbed, and improves the overall stability and smoothness of the culvert section roadbed.

[0015] This utility model has the following beneficial effects:

[0016] 1. Effectively prevent and control frost heave disease in culvert sections of roadbed.

[0017] This utility model, by setting inverted stepped high-strength foamed concrete layers on the top and sides of the culvert, not only ensures the bearing capacity of the roadbed, but also has good heat preservation and buffering effects. It can effectively cope with the freezing problem of the soil around the culvert due to the wind tunnel effect, and also buffer the frost heave force generated by the freezing of the surrounding soil, preventing the frost heave force from being directly transmitted to the culvert structure and causing culvert compression damage, thus extending the service life of the roadbed and culvert.

[0018] 2. Effectively control differential settlement of the roadbed in culvert sections.

[0019] In this invention, the fill base, the inverted terrace structure graded aggregate layer, the inverted terrace high-strength foamed concrete layer, and the culvert are arranged sequentially along the transverse side of the roadbed, forming a multi-layered stiffness gradient transition structure from flexible, semi-flexible to semi-rigid. This effectively avoids abrupt stiffness changes between the culvert concrete structure and the surrounding fill, reduces uneven settlement and misalignment caused by stiffness differences at the connection between the culvert and the roadbed, and improves the overall stability and smoothness of the roadbed in the culvert section.

[0020] 3. Effectively improves the drainage performance of the roadbed in culvert sections.

[0021] This invention features an inclined main drainage pipe within the graded aggregate layer and lateral drainage pipes on the roadbed slope. The drainage pipes are encased in a multi-layered protective structure, including a metal reinforcement cage, a unidirectional permeable layer, and an impermeable membrane. This allows water to be effectively collected from the graded aggregate layer into the main drainage pipe and discharged through the lateral drainage pipes to the drainage ditches on both sides of the roadbed. This improves the drainage capacity of the culvert section roadbed and effectively prevents frost heave and bearing capacity reduction caused by water accumulation in the culvert section roadbed.

[0022] A frost heave and differential settlement control structure suitable for culvert sections in cold regions

[0023] 4. The construction process is simple, highly adaptable, and easy to maintain.

[0024] The graded aggregate layer and high-strength foamed concrete layer used in this utility model are both materials that are readily available in conventional road engineering, and the construction technology is mature and the construction cost is low. In addition, this utility model has a simple structure, and the physical antifreeze and buffer structure used does not rely on external equipment. It is simple to maintain, reliable in operation, and low in cost. Attached Figure Description

[0025] Figure 1 This is a longitudinal cross-sectional schematic diagram of the frost heave and differential settlement control structure for the culvert section roadbed in this utility model.

[0026] Figure 2 This is a schematic cross-sectional view of the frost heave and differential settlement control structure for the culvert section roadbed in this utility model.

[0027] Figure 3 This is a schematic diagram of the cross-sectional structure of the main water collection pipe in this utility model.

[0028] Figure 4 This is a schematic diagram of the outermost metal reinforcing cage of the main water collection pipe in this utility model.

[0029] In the diagram, 1 is the roadbed; 2 is the fill base; 3 is the graded aggregate layer of the inverted terrace structure; 4 is the main water collection pipe; 5 is the high-strength foamed concrete layer of the inverted terrace; 6 is the culvert; 7 is the drainage ditch; 8 is the lateral drainage pipe; 401 is the metal reinforcement cage; 402 is the unidirectional permeable layer; and 403 is the impermeable membrane. Detailed Implementation

[0030] like Figure 1 and Figure 2 As shown, this utility model provides a frost heave and differential settlement control structure suitable for culvert sections in cold regions. It includes a roadbed 1, a fill base 2, an inverted terrace structure graded aggregate layer 3, an inverted terrace high-strength foamed concrete layer 5, and a culvert 6 arranged sequentially from top to bottom. Both the inverted terrace structure graded aggregate layer 3 and the inverted terrace high-strength foamed concrete layer 5 adopt a stepped structure to increase their contact area with the surrounding soil, forming a good interlocking and stress transition structure suitable for frost heave and differential settlement control of culvert sections in cold regions.

[0031] Specifically, the inverted stepped high-strength foamed concrete layer 5 is located above and on both sides of the culvert 6, forming an overall encapsulation structure for the culvert. The two sides of this high-strength foamed concrete layer are stepped, with a height-to-width ratio of 1:(1.5~2), and the height from the top to the top of the culvert 6 is ≥0.5m. This arrangement ensures sufficient rigidity above and on the sides of the culvert, while effectively slowing down heat transfer through the low thermal conductivity of the high-strength foamed concrete, thus providing insulation and frost protection. At the same time, it buffers the frost heave force generated by the freezing of the surrounding soil, preventing the culvert from being squeezed and damaged.

[0032] Specifically, the graded aggregate layer can be made of crushed stone, coarse sand, gravel or their graded mixtures, which have good permeability, mechanical stability and a certain degree of flexibility. The optimal material can be selected according to the climate characteristics of different regions.

[0033] like Figure 1 and Figure 2 As shown, the inverted terrace structure graded aggregate layer 3 is provided with an inclined main water collection pipe 4 with an inclination angle of 5° to 10°, which is used to efficiently collect and discharge water in the graded aggregate layer, and prevent water from accumulating in this area and causing frost heave or softening.

[0034] like Figure 3 As shown, the main water collection pipe 4 is inclinedly arranged in the graded aggregate layer 3 of the inverted terrace structure and is arranged at intervals along the width direction (longitudinal direction) of the culvert; the arrangement interval can be 3 to 5m, and can be optimized and adjusted according to local geological conditions, hydrology and drainage needs to ensure that the roadbed of the culvert section has good drainage capacity.

[0035] like Figure 3 and Figure 4 As shown, the main water collection pipe 4 is surrounded by a multi-layered wrapping structure. The outermost layer is a metal reinforcing cage 401, which provides support and protection. The upper part of the second layer is a one-way permeable layer 402, which allows water to enter the interior of the drain pipe from the outside. The lower part of the second layer is an impermeable membrane 403, which prevents water from leaking from the bottom of the drain pipe, thereby effectively controlling the drainage path and improving drainage efficiency.

[0036] A frost heave and differential settlement control structure suitable for culvert sections in cold regions

[0037] like Figure 2 As shown, lateral drainage pipes 8 are installed on both sides of the roadbed 1. One end of the pipe is connected to the main water collection pipe 4, and the other end extends to the toe of the roadbed slope and connects to the drainage ditch 7. This is used to drain the water in the main water collection pipe 4 into the drainage ditch 7 on both sides of the roadbed, thereby improving drainage efficiency, maintaining the stability of the roadbed in the culvert section, and reducing the risk of frost heave and bearing capacity reduction caused by water accumulation.

[0038] This invention provides a frost heave and differential settlement control structure for culvert sections in cold regions. The structure consists of a fill matrix, a stepped aggregate layer, a stepped high-strength foamed concrete layer, and the culvert itself, forming a multi-layered, gradually changing stiffness transition structure from flexible to semi-flexible to semi-rigid along the roadbed. This significantly reduces uneven settlement at the culvert-roadbed interface caused by abrupt stiffness changes, improving the overall stability and driving safety of the culvert transition section. Simultaneously, the high-strength foamed concrete layer possesses excellent insulation and buffering properties, effectively addressing the problem of intensified soil freezing due to the culvert wind tunnel effect. This not only enhances the frost resistance of the culvert section roadbed but also significantly improves drainage and stress adaptability. The overall structure is reliable and suitable for widespread application in cold regions.

[0039] The above are merely preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. For those skilled in the art, all equivalent substitutions, modifications or improvements made to the above embodiments without departing from the spirit and essence of the present utility model should be covered within the scope of protection of the present utility model. In addition, the parts not described in detail in this specification can be regarded as common knowledge of those skilled in the art and can be implemented by existing mature technologies.

Claims

1. A frost heave and differential settlement control structure suitable for culvert sections in cold regions, characterized in that, From top to bottom, it includes: roadbed (1), fill base (2), stepped aggregate layer (3), stepped high-strength foamed concrete layer (5) and culvert (6). The stepped aggregate layer (3) is equipped with a main water collection pipe (4) at the top. The roadbed (1) is equipped with lateral drainage pipes (8) on both sides of the slope. The roadbed (1) is equipped with drainage ditches (7) at both sides of the slope.

2. The anti-frost heave and differential settlement control structure for culvert sections in cold regions according to claim 1, characterized in that: The inverted stepped high-strength foamed concrete layer (5) is located above and on both sides of the culvert (6). The two sides of the inverted stepped high-strength foamed concrete layer (5) are stepped, and the height-to-width ratio of the two steps is 1:(1~1.5). The width of each step is 0.5m~2m. The height from the top of the inverted stepped high-strength foamed concrete layer (5) to the top of the culvert (6) is ≥0.5m.

3. The anti-frost heave and differential settlement control structure for culvert sections in cold regions according to claim 1, characterized in that: The inverted stepped structure graded aggregate layer (3) is located above and on both sides of the inverted stepped high-strength foamed concrete layer (5). The thickness of the inverted stepped structure graded aggregate layer (3) is 0.5m to 1m, and the two sides are stepped. The height-to-width ratio of the two steps is 1:(1 to 1.5), and the width of each step is 0.5m to 2m.

4. The anti-frost heave and differential settlement control structure for culvert sections in cold regions according to claim 1, characterized in that: The main water collection pipe (4) is laid at an incline in the graded aggregate layer (3) of the inverted terrace structure. The main water collection pipe (4) is a permeable pipe with an inclination angle of 5° to 10°. The main water collection pipe (4) is arranged at intervals of 3m to 5m along the width direction of the culvert.

5. The anti-frost heave and differential settlement control structure for culvert sections in cold regions according to claim 1, characterized in that: The main water collection pipe (4) is wrapped with two layers of structure in sequence. The outermost layer is a metal reinforcement cage (401), which provides support and protection. The upper half of the second layer is a one-way permeable layer (402), which allows water to enter the drain pipe from the outside to the inside. The lower half of the second layer is an impermeable membrane (403), which prevents water from leaking from the bottom of the drain pipe.

6. The anti-frost heave and differential settlement control structure for culvert sections in cold regions according to claim 1, characterized in that: Lateral drainage pipes (8) are installed on both sides of the roadbed (1). The lateral drainage pipes (8) are corrosion-resistant and impermeable pipes. One end of the lateral drainage pipes (8) is connected to the main water collection pipe (4), and the other end is connected to the drainage ditch (7) at the toe of the roadbed slope, which is used to discharge the water collected by the main water collection pipe (4) into the drainage ditch (7).

7. The anti-frost heave and differential settlement control structure for culvert sections in cold regions according to claim 1, characterized in that: The filling substrate (2), the inverted terrace structure graded aggregate layer (3), the inverted terrace high-strength foamed concrete layer (5) and the culvert (6) form a multi-layered stiffness gradient transition structure from flexible, semi-flexible to semi-rigid along the culvert transition section roadbed.

Images