Road bed structure

Abstract

The utility model provides a roadbed structure which comprises a pavement and a roadbed which are transversely symmetrical on two sides by taking a longitudinal center line of a road as a symmetry axis and are sequentially arranged from top to bottom, and the roadbed comprises a lower roadbed and an upper roadbed which are sequentially arranged from bottom to top; a cushion layer is arranged at the top of the upper roadbed and is paved by adopting lime stabilized soil or cement stabilized lime-fly ash gravel milling materials; the lower part of the upper roadbed and the lower roadbed are filled with multiple layers of lime stabilized soil mixtures or multiple layers of lime stabilized soil mixtures and multiple layers of cement soil; a base is arranged at the bottom of the lower roadbed and is of a compact rolling structure. The road bed is simple and reasonable in structure and high in integrity, the structural strength and stability of the road bed are improved, the stability and durability of a road surface structural layer are guaranteed, and damage is reduced; the transverse gradient is reasonably designed, road drainage is facilitated, and road driving safety is also facilitated; the process is simplified, the milling material is used for construction of the upper roadbed mattress layer, the construction is simple, the cost is reduced, the emission of construction wastes is reduced, the pollution is reduced, and the environment is protected.

Description

Technical Field

[0001] The utility model relates to the technical field of road subgrade construction engineering, and specifically relates to a subgrade structure. Background Art

[0002] Municipal roads and highways include the road surface for driving and the roadbed. Among them, the part of the roadbed within a depth of 80 cm below the bottom surface of the road surface structure layer is called the subgrade. The subgrade is the foundation of the road surface, and its main function is to bear the load transmitted from the road surface. The subgrade is a roadbed formed by filling or excavating according to the thickness and elevation requirements of the road surface structure layer, and is sorted into a roadbed for paving the road surface.

[0003] The road surface is directly laid on the subgrade. Therefore, strict requirements are put forward for the soil quality, particle size, and compaction degree of the subgrade, especially the upper subgrade. It must be uniform, dense, and have high strength, without looseness and soft spring phenomena. The subgrade of the excavated roadbed must be flat and dense, and compacted to the specified compaction strength.

[0004] However, the existing subgrade structures generally have the following difficulties and problems in the construction and use processes:

[0005] 1. After long-term use, it is easy to cause problems such as road surface collapse and fracture due to insufficient internal strength.

[0006] 2. The subgrade is not firm and has poor stability, resulting in unstable road surface structure and triggering potential safety hazards such as road surface inclination and local road surface damage.

[0007] 3. Using traditional lime soil filling cannot effectively recycle resources, resulting in resource waste and having an adverse impact on the environment.

[0008] 4. The existing subgrade requires a large amount of lime soil paving, which is not only time-consuming and laborious, but also causes pressure on the raw material resources of lime soil, and does not conform to the concept of sustainable development. Summary of the Utility Model

[0009] In view of this, the purpose of the present utility model is to design a subgrade structure to improve the strength and stability of the subgrade structure, thereby improving the stability and durability of the road surface structure and reducing the occurrence of damages; designing a reasonable cross slope of the subgrade structure, which is beneficial to both road drainage and road driving safety; and simplifying the process, using the milled material for the cushion construction of the upper subgrade, with simple and easy construction, reducing costs, and reducing the emission of construction waste, reducing pollution, and protecting the environment.

[0010] The utility model provides a roadbed structure, including: symmetrically arranged on both sides horizontally with the longitudinal center line of the road as the symmetry axis, a road surface and a roadbed arranged in sequence from top to bottom, wherein the roadbed includes: a lower roadbed and an upper roadbed arranged in sequence from bottom to top; a cushion layer is arranged at the top of the upper roadbed, and the cushion layer is paved with lime stabilized soil or cement stabilized lime-fly ash macadam milling material; the milling material is the water-stable gravel mixture scraped off from the original damaged cement stabilized gravel road surface by a milling machine, used as the material for backfilling the original road surface and used as the material for the cushion layer, reducing the discharge of construction waste. Since the old materials are fully utilized, both cost is saved and pollution is reduced, protecting the environment and being beneficial to environmental protection.

[0011] The lower part of the upper roadbed and the lower roadbed are filled with multi-layer lime stabilized soil mixture or multi-layer lime stabilized soil mixture + multi-layer cement soil.

[0012] A base is arranged at the bottom of the lower roadbed, and the base is a compacted structure with a compaction degree ≥ 93%.

[0013] Furthermore, the top surface of the roadbed has a cross slope that slopes downward from the longitudinal center line of the road to the outside of the road. The slopes on both sides of the road surface are called cross slopes, which vary with the type of road surface layer. The cross slope of high-class road surfaces is small, and that of low-class road surfaces is large. The cross slope in arid regions can be appropriately taken as a low value, and the cross slope in rainy regions should be appropriately taken as a high value. To ensure the uniform thickness of each structural layer of the road surface and the roadbed and the need for drainage, the top surface of the roadbed must be made into a cross slope consistent with the crown cross slope of the road surface.

[0014] Furthermore, the cross slope of the top surface of the roadbed is 1.50 - 2.00%.

[0015] Considering the lateral drainage of the road surface, it is naturally desirable that the camber is as large as possible, but too large a camber will pose a threat to driving safety. On the one hand, when the lateral slope is too large, the vehicle is often in eccentric driving, the fuselage is tilted, it is difficult for the driver to control the direction, and the machine parts wear unevenly. On the other hand, it is also easy to cause the wheels to run off sideways along the slope. Therefore, setting a reasonable cross slope of the roadbed is beneficial to the lateral drainage of the road surface and also beneficial to driving safety.

[0016] Furthermore, the edge width of the roadbed is 30 cm wider than the edge width of the road surface on each side.

[0017] The width of the roadbed is an important factor affecting the stability of the road surface and is also the key to the overall stability of the roadbed. Therefore, determining the width of the roadbed is crucial for the stability of the road surface and the economic rationality of the road project.

[0018] Furthermore, the upper roadbed is within the depth range of 0 - 30 cm below the bottom surface of the road surface; the lower roadbed is within the depth range of 30 - 120 cm below the bottom surface of the road surface.

[0019] In one embodiment of the utility model, the lower part of the upper roadbed and the lower roadbed are filled with 4 layers of 20 cm thick lime-stabilized soil layers from top to bottom;

[0020] Preferably, the four 20 cm thick lime-stabilized soil layers are compacted in layers, and the lime dosages are 10%, 8%, 6% and 6% respectively.

[0021] In another embodiment of the utility model, the lower part of the upper roadbed and the lower roadbed are filled with 4 layers of 20 cm thick lime-stabilized soil layers and 2 layers of 20 cm thick cement soil layers from top to bottom;

[0022] Preferably, the 4 20 cm thick lime-stabilized soil layers and the 2 20 cm thick cement soil layers are compacted in layers, and the lime dosages of the 4 20 cm thick lime-stabilized soil layers are 10%, 8%, 6%, and 6%, respectively, and the cement dosages of the 2 20 cm thick cement soil layers are 5%, respectively.

[0023] Preferably, the uppermost lime-stabilized soil layer can be replaced by cement-stabilized fly ash crushed stone milling material.

[0024] Preferably, both lime-stabilized soil and cement soil are constructed using the road-mixing method.

[0025] Furthermore, the road surface comprises: a surface layer and a base layer arranged in sequence from top to bottom, and the surface layer comprises: an upper sealing layer, a permeable layer, an adhesive layer, and a lower sealing layer arranged in sequence from top to bottom;

[0026] The road surface is the layer that is in direct contact with passing vehicles and the atmosphere. It bears the large vertical, horizontal and impact forces of vehicle loads, and is also affected by the erosion of precipitation and temperature changes.

[0027] The permeable layer uses SBS modified emulsified asphalt as the permeable layer oil, the adhesive layer uses SBS modified emulsified asphalt as the adhesive layer oil, and the upper sealing layer uses SBS modified hot asphalt premixed macadam.

[0028] SBS modified asphalt uses matrix asphalt as raw material, adds a certain proportion of SBS modifier, and makes SBS evenly dispersed in the asphalt through methods such as shearing and stirring. At the same time, a certain proportion of exclusive stabilizer is added to form an SBS blend material, and the good physical properties of SBS are used to modify the asphalt. SBS modified emulsified asphalt has good high temperature resistance and low temperature resistance in areas with large temperature differences; it has good rutting resistance, good elasticity and toughness; it improves the anti-fatigue ability of the road surface, especially has good strain ability on highways with large traffic flow and serious overloading, and can reduce the permanent deformation of the road surface; its bonding ability is particularly strong, can significantly improve the tensile ability of the road surface after encountering water, and greatly improves the water stability of the asphalt; it improves the anti-skid ability of the road surface; it enhances the bearing capacity of the road surface; it reduces the asphalt aging phenomenon caused by ultraviolet radiation of the road surface; it reduces the damage caused by vehicle leakage of diesel, engine oil and gasoline.

[0029] Preferably, the surface course uses A-grade road petroleum asphalt; the coarse aggregate for the surface course uses crushed stone; the fine aggregate for the surface course includes natural sand, manufactured sand and stone chips.

[0030] Furthermore, the base course uses cement and / or crushed stone, and the cement uses ordinary Portland cement of 42.5 or slag Portland cement of 32.5 and 42.5.

[0031] Portland cement sets and hardens quickly, has high early strength and late strength, and is suitable for concrete with strong requirements, winter construction concrete, high-strength concrete and prestressed concrete projects for important structures above and below ground; it has good frost resistance and is suitable for concrete projects that are repeatedly frozen and thawed within the range of water level rise and fall in cold regions; it has large heat of hydration and can be used for construction in low-temperature seasons or winter; it has small dry shrinkage and can be used for concrete projects in dry environments; it has good wear resistance and can be used for road surface and ground projects.

[0032] Furthermore, the lower seal coat is arranged between the surface course and the base course, and the lower seal coat uses SBS modified hot asphalt premixed crushed stone.

[0033] Compared with the prior art, the beneficial effects of the roadbed structure of the present utility model are as follows:

[0034] The roadbed structure provided by the present utility model is simple and reasonable, has strong integrity, improves the structural strength and stability of the roadbed structure, ensures the stability and durability of the road surface structure layer, and reduces the occurrence of damages; through reasonable cross slope design, it is beneficial to both road drainage and road driving safety; and it simplifies the process, uses the milled material for the construction of the upper roadbed cushion layer, the construction is simple and easy to operate, reduces the cost, and reduces the discharge of construction waste, reduces pollution and protects the environment. Description of the Drawings

[0035] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present utility model. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0036] Figure 1 It is a schematic cross-sectional structure diagram of the roadbed structure of an embodiment of the present utility model;

[0037] Figure 2 It is a schematic cross-sectional structure diagram of the roadbed structure of another embodiment of the present utility model.

[0038] The reference numerals in the drawings are represented as:

[0039] 1, road surface, 11, surface layer, 12, base layer, 2, roadbed, 21, upper roadbed, 22, lower roadbed, 3, base, 4, cement-stabilized lime-fly ash macadam milling material layer, 5, lime-stabilized soil layer, 6, cement soil layer. Detailed implementation manners

[0040] The following will describe the exemplary embodiments of the present disclosure in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other. The following will describe the present utility model in detail with reference to the drawings and in conjunction with the embodiments.

[0041] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by terms such as "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying 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 construed as a limitation of the present utility model.

[0042] In the description of the present utility model, it should be noted that unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the connection inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present utility model can be understood according to specific situations.

[0043] The embodiments of the present utility model will be specifically described below in conjunction with the accompanying drawings:

[0044] An embodiment of the present utility model provides a roadbed structure. Referring to Figure 1 , 2 as shown, it includes: symmetrically arranged on both sides horizontally with the longitudinal center line of the road as the axis of symmetry, the road surface 1 and the roadbed 2 are sequentially arranged from top to bottom. Among them, the roadbed 2 includes: the lower roadbed 22 and the upper roadbed 21 are sequentially arranged from bottom to top; the upper roadbed 21 is within the depth range of 0 - 30 cm below the bottom surface of the road surface 1; the lower roadbed 22 is within the depth range of 30 - 120 cm below the bottom surface of the road surface 1.

[0045] A cushion layer is provided on the top of the upper roadbed 21, and the cushion layer is paved with lime - stabilized soil or cement - stabilized lime - fly ash macadam milling material; the milling material is the water - stable stone mixture scraped off from the original damaged cement - stabilized crushed stone road surface by a milling machine, used as the backfill material for the original road surface to be used as the material for the cushion layer, reducing the discharge of construction waste. Since the old materials are fully utilized, it not only saves costs but also reduces pollution and protects the environment, being beneficial to environmental protection. The lower part of the upper roadbed 21 and the lower roadbed 22 are filled with multi - layer lime - stabilized soil mixture or multi - layer lime - stabilized soil mixture + multi - layer cement soil; a base 3 is provided at the bottom of the lower roadbed 22, and the base 3 is a compacted structure with a compaction degree ≥ 93%.

[0046] The top surface of the roadbed 2 has a cross - slope that slopes downward from the longitudinal center line of the road to the outside of the road, and the cross - slope of the top surface of the roadbed 2 is the same as the crown cross - slope of the road surface 1. This ensures the uniform thickness of each structural layer of the road surface 1 and the roadbed 2 and the drainage requirements. Specifically, the cross - slope of the top surface of the roadbed 2 is set to 2.00%. Setting a reasonable cross - slope of the roadbed is beneficial to the lateral drainage of the road surface and also beneficial to driving safety.

[0047] The edge width of the roadbed 2 is 30 cm wider than the edge width of the road surface 1 on each side. This design of the roadbed width plays an important role in improving the overall stability of the road surface and the roadbed, and also takes into account the economic rationality of the road project.

[0048] In a preferred embodiment of the present utility model (as shown in Figure 1 ), the lower part of the upper roadbed 21 and the lower roadbed 22 are sequentially filled with a 1 - layer 20 - cm - thick cement - stabilized lime - fly ash macadam milling material layer 4 and 3 layers of 20 - cm - thick lime - stabilized soil layers 5 from top to bottom; the 4 - layer structure is compacted layer by layer. Among them, the lime dosages of the 3 layers of 20 - cm - thick lime - stabilized soil layers 5 are 8%, 6%, and 6% respectively.

[0049] In another preferred embodiment of the present utility model (as shown in Figure 2As shown in the figure, the lower part of the upper roadbed 21 and the lower roadbed 22 are filled with a 20cm thick cement-stabilized fly ash crushed stone milling material layer 4, 3 20cm thick lime-stabilized soil layers 5 and 2 20cm thick cement-soil layers 6 from top to bottom; the 6-layer structure is compacted layer by layer, wherein the lime dosage of the 3 20cm thick lime-stabilized soil 5 is 8%, 6% and 6% respectively, and the cement dosage of the 2 20cm thick cement-soil layers 6 is 5% respectively. Both lime-stabilized soil and cement-soil are constructed by road mixing method.

[0050] The road surface 1 comprises: a surface layer 11 and a base layer 12 arranged in sequence from top to bottom, wherein the surface layer 11 comprises: an upper sealing layer, a permeable layer, an adhesive layer, and a lower sealing layer arranged in sequence from top to bottom;

[0051] The surface layer 11 of the road surface is the layer that directly contacts the passing vehicles and the atmosphere, and is subjected to the large vertical force, horizontal force and impact force of the driving load, and is also affected by the erosion of precipitation and temperature changes.

[0052] The penetration layer uses SBS modified emulsified asphalt as the penetration oil, the adhesive layer uses SBS modified emulsified asphalt as the adhesive oil, and the upper sealing layer uses SBS modified hot asphalt premixed macadam.

[0053] SBS modified emulsified asphalt has good rutting resistance, good elasticity and toughness; it improves the road's fatigue resistance, especially on roads with large traffic and serious overload, it has good strain capacity and can reduce the permanent deformation of the road surface; it has particularly strong bonding ability, which can significantly improve the road surface's tensile strength after contact with water, and greatly improves the water stability of asphalt; it improves the road's anti-skid ability; it enhances the road's bearing capacity; it reduces the aging of asphalt caused by ultraviolet radiation; it reduces the damage caused by vehicle leakage of diesel, engine oil and gasoline.

[0054] Specifically, the surface layer 11 adopts Class A road petroleum asphalt; the coarse aggregate for the surface layer adopts crushed stone; and the fine aggregate for the surface layer includes natural sand, machine-made sand and stone chips.

[0055] The lower seal layer is made of SBS modified hot asphalt premixed macadam.

[0056] The base layer 12 is made of cement and / or crushed stone, and the cement is 42.5 ordinary silicate cement or 32.5, 42.5 slag silicate cement. The silicate cement sets and hardens quickly, has high early strength and late strength, is suitable for concrete with strong requirements, winter construction concrete, has good wear resistance, and can be used for road and ground engineering.

[0057] The roadbed structure of the embodiment of the present utility model is simple and reasonable, with strong integrity, improving the structural strength and stability of the roadbed structure, ensuring the stability and durability of the road surface structure layer, and reducing the occurrence of damages; through a reasonable cross slope design, it is beneficial to both road drainage and road driving safety; and the process is simplified, using the milled material for the construction of the upper roadbed cushion layer, with simple and easy construction, reducing costs, and reducing the discharge of construction waste, reducing pollution, and protecting the environment.

[0058] So far, the technical solution of the present utility model has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present utility model is obviously not limited to these specific embodiments. Without departing from the principle of the present utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present utility model.

[0059] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model; for those skilled in the art, the present utility model can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A roadbed structure, characterized in that, Including: Symmetrically arranged on both sides horizontally with the longitudinal center line of the road as the axis of symmetry, there are a road surface and a roadbed arranged successively from top to bottom. Among them, the roadbed includes a lower roadbed and an upper roadbed arranged successively from bottom to top; a cushion layer is arranged at the top of the upper roadbed, and the cushion layer is paved with lime stabilized soil or cement stabilized lime-fly ash macadam milling material; The lower part of the upper roadbed and the lower roadbed are filled with multiple layers of lime stabilized soil mixture or multiple layers of lime stabilized soil mixture + multiple layers of cement soil; A base is arranged at the bottom of the lower roadbed, and the base is a compacted structure with a compaction degree ≥ 93%; 2. The roadbed structure according to claim 1, characterized in that, The top surface of the roadbed has a cross slope that slopes downward from the longitudinal center line of the road to the outside of the road; 3. The roadbed structure according to claim 2, characterized in that, The cross slope of the top surface of the roadbed is 1.50 - 2.00%; 4. The roadbed structure according to claim 1, characterized in that, The edge width of the roadbed is 30 cm wider than the edge width of the road surface on each side; 5. The roadbed structure according to claim 1, characterized in that, The upper roadbed is within the depth range of 0 - 30 cm below the bottom surface of the road surface; the lower roadbed is within the depth range of 30 - 120 cm below the bottom surface of the road surface; 6. The roadbed structure according to claim 5, characterized in that, The lower part of the upper roadbed and the lower roadbed are filled with 4 layers of 20 cm thick lime stabilized soil layers successively from top to bottom; 7. The roadbed structure according to claim 5, characterized in that, The lower part of the upper roadbed and the lower roadbed are filled with 4 layers of 20 cm thick lime stabilized soil layers and 2 layers of 20 cm thick cement soil layers successively from top to bottom; 8. The roadbed structure according to claim 1, characterized in that, The road surface includes a surface layer and a base layer arranged successively from top to bottom. The surface layer includes a top seal layer, a prime coat, a tack coat, and a bottom seal layer arranged successively from top to bottom; The prime coat uses SBS modified emulsified asphalt as the prime coat oil, the tack coat uses SBS modified emulsified asphalt as the tack coat oil, and the top seal layer uses SBS modified hot asphalt premixed crushed stone; 9. The roadbed structure according to claim 8, characterized in that, The base layer uses cement and / or crushed stone. The cement uses ordinary Portland cement of 42.5 or slag Portland cement of 32.5 and 42.5; 10. The roadbed structure according to claim 8, characterized in that, The bottom seal layer is arranged between the surface layer and the base layer, and the bottom seal layer uses SBS modified hot asphalt premixed crushed stone;

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