Highway subgrade structure using steel slag as filling material

Abstract

The utility model discloses a highway subgrade structure using steel slag as a filling material, which belongs to the technical field of road engineering and comprises a permeable pavement layer, a drainage channel layer, a water retaining layer, a top sealing layer, a steel slag filling layer and a road arch layer are sequentially laid below the permeable pavement layer, and the edge of the steel slag filling layer is filled with an edge covering soil layer. A blind ditch is buried in the edge covering soil layer, one side of the road arch layer is communicated with a first drainage ditch, the ditch face of the first drainage ditch is located on the water outlet side of the drainage groove layer, a second drainage ditch is arranged above the first drainage ditch, and the ditch faces of the second drainage ditch are located on the two sides of the permeable pavement layer. By the adoption of the structure, the drainage groove layer and the permeable pavement layer are arranged above the capping layer, rainwater on the pavement permeates into the drainage groove layer through the permeable pavement layer, the rainwater is guided into the first drainage ditch through the drainage groove layer, the water blocking layer can prevent the rainwater from entering the steel slag filling layer through the capping layer, the steel slag filling layer is prevented from being unstable when encountering water, and the service life of the steel slag filling layer is prolonged. The stability degree of the roadbed is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of road engineering, and in particular relates to a highway subgrade structure using steel slag as a filling material. Background Art

[0002] Steel slag is a byproduct of the steelmaking process. The steel slag produced is a kind of solid waste. If a large amount of steel slag is not recycled, it will inevitably lead to large-scale accumulation of steel slag. This will occupy land and affect the ecological environment. In order to reduce the exploitation of mining resources and meet the construction needs of highway projects at this stage, effectively using industrial waste slag as highway filling materials and turning waste into treasure is an effective way to save resources, solve waste utilization and protect the environment in highway construction.

[0003] The chemical test results of steel slag show that the first five elements are Ca, Fe, Mg, Si, and Al, and the five oxides are CaO, Fe2O, SiO, MgO, and Al2O3. From the perspective of oxide composition, steel slag is chemically stable in a dry environment at room temperature, but its oxides are unstable when exposed to water. This is not considered in the prior art when steel slag is used as a building filling material. Steel slag is easily softened by rainwater for a long time, which is likely to cause dangerous accidents such as collapse. Utility Model Content

[0004] The utility model aims to provide a highway roadbed structure using steel slag as filling material to solve the above problems.

[0005] To achieve the above purpose, the utility model provides the following solutions:

[0006] A highway roadbed structure using steel slag as filling material comprises a permeable pavement layer, below which are sequentially laid a drainage ditch layer, a water retaining layer, a sealing top layer, a steel slag filling layer and a road crown layer, the edge of the steel slag filling layer is filled with a edging soil layer, a blind ditch is buried in the edging soil layer, one side of the road crown layer is connected to a first drainage ditch, the ditch surface of the first drainage ditch is located at the water outlet side of the drainage ditch layer, a second drainage ditch is provided above the first drainage ditch, and the ditch surfaces of the second drainage ditch are located at both sides of the permeable pavement layer.

[0007] Preferably, a unidirectional permeable geotextile is laid between the drainage ditch layer and the permeable pavement layer.

[0008] Preferably, when the roadbed height is greater than 4m, an interlayer is filled in the middle of the embankment, and an isolation layer is filled at the bottom of the embankment, the interlayer is located below the blind ditch, the isolation layer and the interlayer are buried in the slag filling layer, and the isolation layer is between the interlayer and the road arch layer and is close to the road arch layer.

[0009] Preferably, the thickness of the isolation layer is 0.5 m.

[0010] Preferably, the edge soil layer is stepped, and the width and height of the edge soil layer are both 0.5m.

[0011] Preferably, an anti-filter layer is arranged around the blind ditch.

[0012] Preferably, the compacted thickness of the sealing layer is not less than 100 mm.

[0013] Preferably, the drainage trough layer is wavy to facilitate water flow out along the troughs of the drainage trough layer.

[0014] Preferably, a water retaining block is fixedly connected between the first drainage ditch and the second drainage ditch, and the water retaining block is located on a side of the valley away from the drainage ditch layer.

[0015] Compared with the prior art, the utility model has the following advantages and technical effects:

[0016] The utility model arranges a drainage trough layer and a permeable pavement layer above the sealing top layer. The permeable pavement layer infiltrates rainwater from the road surface into the drainage trough layer, and guides the rainwater into the first drainage ditch through the drainage trough layer. The water retaining layer can prevent rainwater from entering the slag filling layer through the sealing top layer, thereby preventing the slag filling layer from being unstable when encountering water, thereby improving the stability of the roadbed. When the amount of rainwater is too large, the permeable pavement layer can directly guide a part of the rainwater into the second drainage ditch, thereby reducing the pressure of the drainage trough layer to discharge rainwater. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor:

[0018] Figure 1 It is a schematic diagram of the structure of the utility model;

[0019] Figure 2 It is the front view of the utility model;

[0020] Figure 3 It is a structural schematic diagram of the drainage trough layer;

[0021] Figure numerals: 1. capping layer; 2. edging soil layer; 3. blind ditch; 4. road arch layer; 5. isolation layer; 6. slag filling layer; 7. interlayer; 8. first drainage ditch; 9. second drainage ditch; 10. water retaining block; 11. permeable pavement layer; 12. drainage trough layer; 13. water retaining layer. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] Reference Figures 1 to 3 As shown, the utility model provides a highway roadbed structure using steel slag as a filling material, including the following embodiments:

[0025] Embodiment 1:

[0026] It includes a permeable pavement layer 11, below which are laid a drainage trough layer 12, a water retaining layer 13, a sealing top layer 1, a steel slag filling layer 6 and a road arch layer 4 in sequence, the edge of the steel slag filling layer 6 is filled with a edging soil layer 2, in which a blind ditch 3 is buried, one side of the road arch layer 4 is connected to a first drainage ditch 8, the ditch surface of the first drainage ditch 8 is located on the water outlet side of the drainage trough layer 12, a second drainage ditch 9 is provided above the first drainage ditch 8, and the ditch surface of the second drainage ditch 9 is located on both sides of the permeable pavement layer 11.

[0027] A drainage trough layer 12 and a permeable pavement layer 11 are arranged above the capping layer 1. The permeable pavement layer 11 allows rainwater from the road surface to penetrate into the drainage trough layer 12, and guides the rainwater into the first drainage ditch 8 through the drainage trough layer 12. The water retaining layer 13 can prevent rainwater from entering the slag filling layer 6 through the capping layer 1, thereby preventing the slag filling layer 6 from becoming unstable when encountering water, thereby improving the stability of the roadbed. When the amount of rainwater is too large, the permeable pavement layer 11 can directly guide part of the rainwater into the second drainage ditch 9, reducing the pressure of the drainage trough layer 12 to drain rainwater.

[0028] The steel slag filling layer 6 as roadbed filler should be decomposed stably and have sufficient strength. The water expansion rate should not be greater than 2.0%, the pressure steam pulverization rate should not be greater than 5.0%, the metallic iron content in the steel slag should not be greater than 2.0%, and the free calcium oxide content should be less than 3.0%. Old slag that has been stored for more than one year should be used.

[0029] The slag filling layer 6 should be filled in layers, and the maximum compacted thickness of each layer should not exceed 300mm.

[0030] To further optimize the solution, a one-way permeable geotextile is laid between the drainage ditch layer 12 and the permeable pavement layer 11 .

[0031] One-way permeable geotextile can prevent rainwater backflow.

[0032] According to the further optimization scheme, the edge soil layer 2 is stepped, and the width and height of the edge soil layer 2 are both 0.5m.

[0033] The edge soil layer 2 should be made of fine-grained soil. The edge soil layer 2 can protect the slope and shoulder, and the stepped setting makes the edge soil layer 2 more stable.

[0034] To further optimize the solution, an anti-filter layer is set around the blind ditch 3.

[0035] According to the further optimization scheme, the compacted thickness of the capping layer 1 is not less than 100 mm.

[0036] According to a further optimization scheme, the drainage trough layer 12 is wavy in shape, so that water can flow out along the trough of the drainage trough layer 12 .

[0037] According to a further optimized solution, a water retaining block 10 is fixedly connected between the first drainage ditch 8 and the second drainage ditch 9 , and the water retaining block 10 is located on a side of the ditch away from the drainage groove layer 12 .

[0038] When the flow rate of water discharged into the first drainage ditch 8 is too fast, the water retaining block 10 can ensure that the rainwater only flows in the first drainage ditch 8 .

[0039] Embodiment 2:

[0040] The only difference between this embodiment and Embodiment 1 is that: when the roadbed height is greater than 4m, an interlayer 7 is filled in the middle of the embankment, and an isolation layer 5 is filled at the bottom of the embankment, the interlayer 7 is located below the blind ditch 3, the isolation layer 5 and the interlayer 7 are buried in the slag filling layer 6, and the isolation layer 5 is between the interlayer 7 and the road crown layer 4 and is close to the road crown layer 4.

[0041] According to a further optimized solution, the thickness of the isolation layer 5 is 0.5 m.

[0042] The interlayer 7 can improve the stability of the slag filling layer 6. The utility model takes into account the problem that when the roadbed height is greater than 4m, the groundwater level in the highway foundation is shallow and water easily accumulates on the surface. An isolation layer 5 is provided to solve these problems. The isolation layer 5 can be made of clay with a plasticity index of not less than 6 and meeting the strength requirements.

[0043] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0044] The embodiments described above are only descriptions of the preferred methods of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A highway subgrade structure using steel slag as filling material, characterized in that: The invention comprises a permeable pavement layer (11), wherein a drainage trough layer (12), a water retaining layer (13), a sealing layer (1), a steel slag filling layer (6) and a road crown layer (4) are sequentially laid below the permeable pavement layer (11); the edge of the steel slag filling layer (6) is filled with a edging soil layer (2), a blind ditch (3) is buried in the edging soil layer (2); one side of the road crown layer (4) is connected to a first drainage ditch (8), the ditch surface of the first drainage ditch (8) is located at the water outlet side of the drainage trough layer (12); a second drainage ditch (9) is provided above the first drainage ditch (8), and the ditch surface of the second drainage ditch (9) is located at both sides of the permeable pavement layer (11).

2. The highway subgrade structure using steel slag as filling material according to claim 1, characterized in that: A one-way permeable geotextile is laid between the drainage ditch layer (12) and the permeable pavement layer (11).

3. The highway subgrade structure using steel slag as filling material according to claim 1, characterized in that: When the roadbed height is greater than 4 m, an interlayer (7) is filled in the middle of the embankment, and an isolation layer (5) is filled at the bottom of the embankment, the interlayer (7) is located below the blind ditch (3), the isolation layer (5) and the interlayer (7) are buried in the steel slag filling layer (6), and the isolation layer (5) is between the interlayer (7) and the road crown layer (4) and is in close contact with the road crown layer (4).

4. The highway subgrade structure using steel slag as filling material according to claim 3, characterized in that: The thickness of the isolation layer (5) is 0.5 m.

5. The highway subgrade structure using steel slag as filling material according to claim 1, characterized in that: The edge soil layer (2) is stepped, and the width and height of the edge soil layer (2) are both 0.5 m.

6. The highway subgrade structure using steel slag as filling material according to claim 1, characterized in that: An anti-filter layer is arranged on the periphery of the blind ditch (3).

7. The highway subgrade structure using steel slag as filling material according to claim 1, characterized in that: The compacted thickness of the sealing layer (1) is not less than 100 mm.

8. The highway subgrade structure using steel slag as filling material according to claim 1, characterized in that: The drainage groove layer (12) is wavy in shape, which facilitates water to flow out along the troughs of the drainage groove layer (12).

9. The highway subgrade structure using steel slag as filling material according to claim 1, characterized in that: A water retaining block (10) is fixedly connected between the first drainage ditch (8) and the second drainage ditch (9), and the water retaining block (10) is located on a side of the ditch away from the drainage groove layer (12).

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