Silt roadbed drainage anti-seepage structure and construction process

Abstract

The application provides a silt roadbed drainage anti-seepage structure and a construction process, which comprises a silt main roadbed, the top of the silt main roadbed is provided with an upper recycled brick aggregate layer, the bottom of the silt main roadbed is provided with a lower recycled brick aggregate layer, and the two sides of the silt main roadbed are provided with side recycled brick aggregate layers; drainage geocells are arranged in the upper recycled brick aggregate layer, the lower recycled brick aggregate layer and the side recycled brick aggregate layers, and the drainage geocells in the lower recycled brick aggregate layer are multilayered and are laid into the silt main roadbed. The capillary water in the silt roadbed main body is discharged by arranging the drainage geocells, and the strength and stability of the silt roadbed are enhanced; the recycled brick aggregate layers are arranged at the bottom, the two sides and the top of the silt roadbed main body for drainage, which not only prevents the upward infiltration of underground water, but also prevents the downward infiltration of rainwater from the road surface and the slope, thereby reducing the increase of the moisture of the silt roadbed main body.

Description

Technical Field

[0001] This invention relates to the field of roadbed engineering technology, specifically to a drainage and seepage prevention structure and construction process for silty soil roadbed. Background Technology

[0002] Silt is a low-plasticity soil with special engineering properties. It is mostly composed of sand and silt particles with low clay content. Often considered waste soil in engineering construction, its resource utilization rate is low. Using waste silt from construction excavation for roadbed filling is a common way to utilize it. However, using silt for roadbed filling presents several problems: poor water stability (high hardening strength when dry, low softening strength after contact with water); significant capillary action, exacerbating water absorption and softening, leading to reduced strength; and difficulty in compaction, resulting in insufficient strength and significant later settlement. Therefore, silt roadbeds are prone to uneven settlement, pavement cracking, instability, and collapse. Summary of the Invention

[0003] The first objective of this invention is to provide a drainage and seepage prevention structure for silty soil roadbeds, addressing the aforementioned problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A drainage and seepage prevention structure for silty soil roadbed includes: a silty soil main roadbed, characterized in that: an upper recycled brick aggregate layer is provided on the top of the silty soil main roadbed, a lower recycled brick aggregate layer is provided at the bottom of the silty soil main roadbed, and side recycled brick aggregate layers are provided on both sides of the silty soil main roadbed; drainage geocells are laid in the upper recycled brick aggregate layer, the lower recycled brick aggregate layer, and the side recycled brick aggregate layers, and the drainage geocells in the lower recycled brick aggregate layer are multi-layered and laid into the silty soil main roadbed.

[0006] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0007] As a preferred technical solution of the present invention: a surface layer is laid on the upper recycled brick aggregate layer.

[0008] As a preferred technical solution of the present invention: drainage ditches are provided on both sides of the lower recycled brick aggregate layer.

[0009] As a preferred technical solution of the present invention: a layer of recycled planting soil is laid on the outside of the side recycled brick aggregate layer.

[0010] As a preferred technical solution of the present invention: a geotextile is provided between the recycled planting soil layer and the side recycled brick aggregate layer.

[0011] As a preferred technical solution of the present invention: geotextile is provided at the bottom of the side recycled brick aggregate layer.

[0012] As a preferred technical solution of the present invention: geotextile is provided on both sides of the lower recycled brick aggregate layer.

[0013] As a preferred technical solution of the present invention: the multi-layer drainage geocells in the lower recycled brick aggregate layer are connected by snap-fit.

[0014] The second objective of this invention is to provide a construction process for a drainage and seepage prevention structure for silty soil subgrade.

[0015] Therefore, the above-mentioned objective of the present invention is achieved through the following technical solution:

[0016] A construction process for a drainage and seepage prevention structure for silty soil subgrade, characterized in that: the construction process is based on the seepage prevention structure described above, and includes the following steps:

[0017] S1. Clean and level the construction area where the roadbed filling is to be carried out;

[0018] S2. Lay the first layer of drainage geocells at the bottom, and fill them with recycled brick aggregate to form the lower recycled brick aggregate layer. The thickness of the lower recycled brick aggregate layer should meet the following requirements:

[0019] and (1)

[0020] In the formula: d bb The thickness of the underlying recycled brick aggregate layer is measured in meters (m) and k. silt B is the permeability coefficient of silt, in m / s; b The width of the roadbed is in meters (m); k brick K represents the permeability coefficient of recycled brick aggregate, in m / s. sf Let be the permeability coefficient of the foundation at the bottom of the roadbed, in m / s;

[0021] S3. After the lower recycled brick aggregate layer is laid, geotextile is laid on both sides and drainage ditches are constructed to prevent the recycled brick aggregate from falling off. The drainage of the geotextile should meet the following requirements:

[0022] (2)

[0023] In the formula: k g ρ is the permeability coefficient of the geotextile, in m / s;

[0024] S4. Lay the second layer of drainage geocells at the bottom, connecting them to the first layer using clips. Fill the second layer of drainage geocells with silty soil as the main roadbed. The silty soil main roadbed is constructed using a layered filling and compaction method, with each layer having a loose thickness of 20-30 cm, slightly higher than the second layer of drainage geocells. The basic compaction process is as follows: initial leveling with a bulldozer, leveling with a screed, one pass of static compaction, two passes of low-frequency large-amplitude vibratory compaction, two passes of high-frequency small-amplitude vibratory compaction, and one pass of static compaction, using a variable frequency and amplitude method. The amplitude of the large-amplitude vibration is 2.1 mm, and the amplitude of the small-amplitude vibration is 1.1 mm. The frequencies of the large-amplitude and small-amplitude vibrations should meet the following requirements according to the resonance principle:

[0025] Large amplitude vibration frequency: (3)

[0026] Small amplitude vibration frequency: (4)

[0027] In the formula: f d The frequency of large-amplitude vibration is Hz; f x The frequency of small-amplitude vibration is Hz; ρ d The dry density of silt, in g / cm³ 3 ;

[0028] S5. After the first layer of silty soil subgrade is compacted, lay the third layer of drainage geocells and connect them to the second layer of drainage geocells using clips. Continue filling the silty soil according to the above requirements. Lay the drainage geocells and the silty soil subgrade in sequence until the height of the drainage geocells reaches 1 / 2 of the subgrade height. When the height of the drainage geocells reaches 1 / 2 of the subgrade height, stop laying drainage geocells and continue filling the silty soil subgrade according to the filling requirements.

[0029] S6. After the main silt subgrade is laid, drainage geocells are laid on top, and recycled brick aggregate is filled in to form an upper recycled brick aggregate layer. The thickness of the upper recycled brick aggregate layer should meet the following requirements:

[0030] (5)

[0031] In the formula: d ub The thickness of the upper recycled brick aggregate layer is measured in meters (m) and k. surface B is the permeability coefficient of the surface layer material, in m / s; u The width of the top of the roadbed, in meters (m).

[0032] S7. After the main silt subgrade and the upper recycled brick aggregate layer are laid, drainage geocells are laid on both sides and filled with recycled brick aggregate to form a side recycled brick aggregate layer. At the same time, geotextile is laid above the drainage ditch to prevent the recycled brick aggregate from falling off. The thickness of the side recycled brick aggregate layer should meet the following requirements:

[0033] (6)

[0034] In the formula: d sb The thickness of the side-recycled brick aggregate layer is measured in meters (m) and k. psoil θ is the permeability coefficient of the recycled planting soil, m / s; H is the height from the bottom of the silt main subgrade to the top of the surface layer, m; θ is the inclination angle of the side recycled brick aggregate layer, °;

[0035] S8. A layer of recycled planting soil is laid on top of the side recycled brick aggregate layer. This layer is generally composed of recycled silty clay or clay rich in organic matter. On the one hand, planting landscape grass on the recycled planting soil layer reduces rainwater infiltration during rainfall and absorbs water from the soil layer during sunny weather. On the other hand, the capillary resistance effect between the recycled planting soil layer and the side recycled brick aggregate layer reduces rainwater infiltration into the side recycled brick aggregate layer, thereby reducing water infiltration into the silty soil main subgrade. The thickness of the recycled planting soil layer is generally 0.2-0.4 m.

[0036] S9. Finally, the surface layer is poured to complete the paving.

[0037] This invention provides a drainage and seepage prevention structure and construction process for silty soil subgrade, which has the following beneficial effects: by setting drainage geocells, capillary water inside the silty soil subgrade is drained, enhancing the strength and stability of the silty soil subgrade; recycled brick aggregate layers are set at the bottom, sides and top of the silty soil subgrade for drainage, which not only prevents groundwater from seeping upwards, but also prevents rainwater from seeping downwards from the road surface and slopes, reducing the increase of moisture in the silty soil subgrade; at the same time, it reduces the use of natural sand and gravel, achieving the goal of recycling construction waste; no water-blocking sealants or other solution-based reagents are used, eliminating the need for strict control of the moisture content of the silty soil, simplifying construction requirements. Attached Figure Description

[0038] Figure 1 This is a front view of the silt roadbed drainage and seepage prevention structure provided by the present invention;

[0039] Figure 2 This is a top view of the silt roadbed drainage and seepage prevention structure provided by the present invention;

[0040] Figure 3 for Figure 1 Cross-sectional view along the AA direction;

[0041] In the diagram: 1-Silty soil subgrade; 2-Surface layer; 3-Upper recycled brick aggregate layer; 4-Recycled planting soil layer; 5-Side recycled brick aggregate layer; 6-Geotextile; 7-Drainage ditch; 8-Lower recycled brick aggregate layer; 9-Drainage geocell; 10-Snap fastener. Detailed Implementation

[0042] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0043] like Figure 1-3 As shown, a drainage and seepage prevention structure and construction technology for silty soil subgrade includes a silty soil main subgrade 1. The top of the silty soil main subgrade 1 is provided with an upper recycled brick aggregate layer 3, the bottom of the silty soil main subgrade 1 is provided with a lower recycled brick aggregate layer 8, and the two sides of the silty soil main subgrade 1 are provided with side recycled brick aggregate layers 5. Drainage geocells 9 are laid in the upper recycled brick aggregate layer 3, the lower recycled brick aggregate layer 8, and the side recycled brick aggregate layers 5. The drainage geocells 9 in the lower recycled brick aggregate layer 8 are multi-layered and laid into the silty soil main subgrade 1.

[0044] The surface layer 2 is laid on top of the recycled brick aggregate layer 3.

[0045] Drainage ditches 7 are provided on both sides of the lower recycled brick aggregate layer 8.

[0046] A layer of recycled planting soil 4 is laid on the outside of the side recycled brick aggregate layer 5.

[0047] Geotextile 6 is installed between the recycled planting soil layer 4 and the side recycled brick aggregate layer 5.

[0048] Geotextile 6 is installed at the bottom of the side recycled brick aggregate layer 5.

[0049] Geotextile 6 is installed on both sides of the lower recycled brick aggregate layer 8.

[0050] The multi-layer drainage geocells 9 in the lower recycled brick aggregate layer 8 are connected by snap-fit ​​10.

[0051] Specifically, the above-mentioned drainage and seepage prevention structure and construction technology for silty soil subgrade are implemented in the following ways:

[0052] S1. Clean and level the construction area where the roadbed filling is to be carried out;

[0053] S2. The first layer of drainage geocells 9 is laid at the bottom, and recycled brick aggregate is filled in to form the lower recycled brick aggregate layer 8. The thickness of the lower recycled brick aggregate layer 8 should meet the following requirements:

[0054] and (1)

[0055] In the formula: d bb The thickness of the lower recycled brick aggregate layer 8 is in meters (m); k siltB is the permeability coefficient of silt, in m / s; b The width of the roadbed is in meters (m); k brick K represents the permeability coefficient of recycled brick aggregate, in m / s. sf Let be the permeability coefficient of the foundation at the bottom of the roadbed, in m / s;

[0056] S3. After the lower recycled brick aggregate layer 8 is laid, geotextile 6 is laid on both sides and drainage ditches 7 are constructed to prevent the recycled brick aggregate from falling off. The drainage of the geotextile should meet the following requirements:

[0057] (2)

[0058] In the formula: k g ρ is the permeability coefficient of the geotextile, in m / s;

[0059] S4. Lay the second layer of drainage geocells 9 at the bottom, connecting it to the first layer of drainage geocells 9 via clips 10; fill the second layer of drainage geocells 9 with silty soil main roadbed 1, wherein the silty soil main roadbed 1 adopts a layered filling and compaction construction method, with each layer having a loose thickness of 20-30 cm, slightly higher than the second layer of drainage geocells 9. The basic compaction process is: initial leveling with a bulldozer, leveling with a screed, one pass of static compaction, two passes of low-frequency large-amplitude vibration compaction, two passes of high-frequency small-amplitude vibration compaction, and one pass of static compaction, using a variable frequency and amplitude method; wherein, the amplitude of the large-amplitude vibration is 2.1 mm, and the amplitude of the small-amplitude vibration is 1.1 mm; the frequencies of the large-amplitude vibration and the small-amplitude vibration should meet the following requirements according to the resonance principle:

[0060] Large amplitude vibration frequency: (3)

[0061] Small amplitude vibration frequency: (4)

[0062] In the formula: f d The frequency of large-amplitude vibration is Hz; f x The frequency of small-amplitude vibration is Hz; ρ d The dry density of silt, in g / cm³ 3 ;

[0063] S5. After the first layer of silty soil main roadbed 1 is compacted, the third layer of drainage geocells 9 is laid and connected to the second layer of drainage geocells 9 through clips 10. Silt is then filled according to the above requirements. The drainage geocells 9 and the silty soil main roadbed 1 are laid in sequence until the height of the drainage geocells 9 reaches 1 / 2 of the roadbed height. When the height of the drainage geocells 9 reaches 1 / 2 of the roadbed height, the drainage geocells 9 are no longer laid, and the filling is continued according to the filling requirements of the silty soil main roadbed 1.

[0064] S6. After the main silt subgrade 1 is laid, drainage geocells 9 are laid on top, and recycled brick aggregate is filled in to form the upper recycled brick aggregate layer 3. The thickness of the upper recycled brick aggregate layer 3 should meet the following requirements:

[0065] (5)

[0066] In the formula: d ub The thickness of the upper recycled brick aggregate layer 3 is in meters (m); k surface B is the permeability coefficient of the surface layer material, in m / s; u The width of the top of the roadbed, in meters (m).

[0067] After the main subgrade 1 (S7) and the upper recycled brick aggregate layer 3 are laid, drainage geocells 9 are laid on both sides and filled with recycled brick aggregate to form the side recycled brick aggregate layer 5. At the same time, geotextile 6 is laid above the drainage ditch 7 to prevent the recycled brick aggregate from falling off. The thickness of the side recycled brick aggregate layer 5 should meet the following requirements:

[0068] (6)

[0069] In the formula: d sb The thickness of the side recycled brick aggregate layer 5 is in meters (m); k psoil θ is the permeability coefficient of the recycled planting soil, m / s; H is the height from the bottom of the silt main subgrade to the top of the surface layer, m; θ is the inclination angle of the side recycled brick aggregate layer 5, °;

[0070] S8. A recycled planting soil layer 4 is laid on top of the side recycled brick aggregate layer 5. It is generally a recycled silty clay or clay rich in organic matter. On the one hand, landscape grass is planted on the recycled planting soil layer 4. The plants reduce rainwater infiltration during rainfall and absorb water from the soil layer during sunny weather. On the other hand, the capillary resistance effect between the recycled planting soil layer 4 and the side recycled brick aggregate layer 5 reduces rainwater infiltration into the side recycled brick aggregate layer, thereby reducing water infiltration into the silty soil main roadbed 1. The thickness of the recycled planting soil layer 4 is generally 0.2-0.4 m.

[0071] S9. Finally, pour the second surface layer to complete the paving.

[0072] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A construction process for a drainage and seepage prevention structure for silty soil subgrade, characterized in that: The construction process is based on a silt roadbed drainage and seepage prevention structure, including: a silt main roadbed (1), the top of the silt main roadbed (1) is provided with an upper recycled brick aggregate layer (3), the bottom of the silt main roadbed (1) is provided with a lower recycled brick aggregate layer (8), and the two sides of the silt main roadbed (1) are provided with side recycled brick aggregate layers (5); a surface layer (2) is laid on the upper recycled brick aggregate layer (3). Drainage geocells (9) are laid in the upper recycled brick aggregate layer (3), the lower recycled brick aggregate layer (8), and the side recycled brick aggregate layer (5). The drainage geocells (9) in the lower recycled brick aggregate layer (8) are multi-layered and laid in the silt main roadbed (1). And includes the following steps: S1. Clean and level the construction area where the roadbed filling is to be carried out; S2. The first layer of drainage geocells (9) is laid at the bottom, and recycled brick aggregate is filled in to form the lower recycled brick aggregate layer (8), wherein the thickness of the lower recycled brick aggregate layer (8) should meet the following requirements: and (1) In the formula: d bb The thickness of the lower recycled brick aggregate layer (8) is m; k silt B is the permeability coefficient of silt, in m / s; b The width of the roadbed is in meters (m); k brick K represents the permeability coefficient of recycled brick aggregate, in m / s. sf Let be the permeability coefficient of the foundation at the bottom of the roadbed, in m / s; S3. After the lower recycled brick aggregate layer (8) is laid, geotextile (6) is laid on both sides and drainage ditches (7) are constructed to prevent the recycled brick aggregate from falling off. The drainage of the geotextile should meet the following requirements: （2） In the formula: k g ρ is the permeability coefficient of the geotextile, in m / s; S4. Lay the second layer of drainage geocells (9) at the bottom and connect them to the first layer of drainage geocells (9) through clips (10); fill the second layer of drainage geocells (9) with silt main roadbed (1), wherein the silt main roadbed (1) adopts the construction method of layered filling and compaction, and the thickness of each layer is 20-30 cm, which should be slightly higher than the second layer of drainage geocells (9). The basic compaction process is: bulldozer initial leveling, screeding, static compaction once, low-frequency large amplitude vibration compaction twice, high-frequency small amplitude vibration compaction twice, and static compaction once, using the variable frequency and variable amplitude method; wherein, the amplitude of large amplitude vibration is 2.1 mm, and the amplitude of small amplitude vibration is 1.1 mm; the frequencies of large amplitude vibration and small amplitude vibration should meet the following requirements according to the resonance principle: Large amplitude vibration frequency: (3) Small amplitude vibration frequency: (4) In the formula: f d The frequency of large-amplitude vibration is Hz; f x The frequency of small-amplitude vibration, in Hz; ρ d The dry density of silt, in g / cm³ 3 ; S5. After the first layer of silty soil main roadbed (1) is compacted, the third layer of drainage geocells (9) is laid and connected to the second layer of drainage geocells (9) through the clips (10). The silty soil is then filled according to the above requirements. The drainage geocells (9) and the silty soil main roadbed (1) are laid in sequence until the height of the drainage geocells (9) reaches 1 / 2 of the roadbed height. When the height of the drainage geocells (9) reaches 1 / 2 of the roadbed height, the drainage geocells (9) are no longer laid. The filling is then carried out according to the filling requirements of the silty soil main roadbed (1). S6. After the main silt subgrade (1) is laid, drainage geocells (9) are laid on top and recycled brick aggregate is filled in to form an upper recycled brick aggregate layer (3). The thickness of the upper recycled brick aggregate layer (3) should meet the following requirements: （5） In the formula: d ub The thickness of the upper recycled brick aggregate layer (3) is m; k surface B is the permeability coefficient of the surface layer material, in m / s; u The width of the top of the roadbed, in meters (m). S7. After the main subgrade (1) and the upper recycled brick aggregate layer (3) are laid, drainage geocells (9) are laid on both sides and filled with recycled brick aggregate to form a side recycled brick aggregate layer (5). Geotextile (6) is installed at the bottom of the side recycled brick aggregate layer (5). At the same time, geotextile (6) is laid above the drainage ditch (7) to prevent the recycled brick aggregate from falling off. The thickness of the side recycled brick aggregate layer (5) should meet the following requirements: （6） In the formula: d sb The thickness of the side recycled brick aggregate layer (5) is m; k psoil denoted as the permeability coefficient of the regenerated planting soil, in m / s; H The height is measured in meters (m) from the bottom of the silty soil subgrade to the top of the surface layer. θ The inclination angle of the side recycled brick aggregate layer (5) is °; S8. A recycled planting soil layer (4) is laid on top of the side recycled brick aggregate layer (5). The soil is recycled silty clay or clay rich in organic matter. Geotextile (6) is set between the recycled planting soil layer (4) and the side recycled brick aggregate layer (5). On the one hand, landscape grass is planted on the recycled planting soil layer (4). The plants reduce rainwater infiltration during rainfall and absorb water in the soil layer during sunny weather. On the other hand, the capillary resistance effect between the recycled planting soil layer (4) and the side recycled brick aggregate layer (5) reduces rainwater infiltration into the side recycled brick aggregate layer, thereby reducing water infiltration into the silty soil main subgrade (1). The thickness of the recycled planting soil layer (4) is 0.2-0.4 m. S9. Finally, the surface layer (2) is poured to complete the laying.

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