A method for road subgrade connection based on solidification technology

Abstract

The present application relates to a kind of based on solidification technology's road subgrade connection method, according to the range of subgrade work area at the junction between the first subgrade and the second subgrade, solidified soil transition layer is arranged between the two, the solidified soil transition layer covers the range of subgrade work area;According to the expected load above the first subgrade and the second subgrade, the range of the solidified soil transition layer and the number of layers are designed, wherein the range of the solidified soil transition layer refers to one end of the solidified soil transition layer is located in the first subgrade, the other end is located in the second subgrade, and the range is the length of entering the first subgrade or the second subgrade respectively, the number of layers of the solidified soil transition layer refers to one or more than one layer of the solidified soil transition layer is arranged between the first subgrade and the second subgrade along the height direction of subgrade.The advantages of the present application are: less material type, easy to obtain, environmental protection, simple and convenient construction, stable and reliable performance, low cost.

Description

Technical Field

[0001] This invention relates to the field of new construction and reconstruction engineering technology for municipal roads or highways, and in particular to a method for connecting roadbeds based on solidification technology. Background Technology

[0002] At the cut-fill junction of newly built roads and the junction of new and old roads in reconstruction and expansion, the uneven settlement of the roadbed on both sides of the junction often leads to uneven settlement of the roadbed, affecting the stability and durability of the road structure. Commonly used measures for the connection of cut-fill junction and new and old roadbed include step excavation, layer-by-layer laying of geotextiles, surcharge or natural settlement, etc. The main problems are: (1) the quality requirements of the backfill soil for step excavation are high, and the utilization rate of the original soil in the existing site is low; (2) layer-by-layer laying of geotextiles is relatively complicated, and large machinery is not suitable for compaction on the geotextiles, the construction period is long, and the quality is difficult to control; (3) the construction period of roadbed surcharge preloading and natural settlement is long.

[0003] In summary, conventional methods involve large amounts of borrowed earthwork, utilize little of the original soil, are environmentally unfriendly, require numerous construction procedures, have high project costs, and struggle to guarantee quality. Therefore, a new roadbed connection technology is needed to address these issues. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by providing a roadbed connection method based on solidification technology. This method achieves organic connection at the junction of the old and new roadbeds by laying a solidified soil transition layer composed of undisturbed soil treated with solidification technology. This improves environmental friendliness, ease of construction, reliability, and economy.

[0005] The objective of this invention is achieved through the following technical solutions:

[0006] A roadbed connection method based on solidification technology is used for connecting two different roadbeds, the two roadbeds including a first roadbed and a second roadbed, characterized by comprising the following methods:

[0007] Based on the working area of ​​the roadbed at the junction between the first roadbed and the second roadbed, a solidified soil transition layer is set between them, and the solidified soil transition layer covers the working area of ​​the roadbed.

[0008] Based on the expected load above the first and second roadbeds, the range and number of layers of the solidified soil transition layer are designed. The range of the solidified soil transition layer refers to the length of the solidified soil transition layer extending into the first or second roadbed, with one end located at the first roadbed and the other end at the second roadbed. The number of layers of the solidified soil transition layer refers to the provision of one or more solidified soil transition layers between the first and second roadbeds along the height direction of the roadbed.

[0009] The solidified soil transition layer is backfilled and compacted in layers, with each layer not exceeding 0.3m in thickness.

[0010] A stepped structure is constructed between the first roadbed and the second roadbed, with the height of each step matching the thickness of the solidified soil transition layer, and one end of the solidified soil transition layer being placed on the step.

[0011] The overall thickness of the solidified soil transition layer is achieved by superimposing the corresponding solidified soil transition layer on each of the stepped steps.

[0012] A seepage-proof geotextile is laid on the top surface of the solidified soil transition layer to form a seepage-proof pavement structure.

[0013] An impermeable geotextile is laid on the bottom surface of the solidified soil transition layer and a drainage ditch or blind pipe is installed inside. At the same time, the embankment is filled with permeable materials.

[0014] The solidified soil transition layer includes undisturbed soil and a solidifying agent, wherein the organic matter content of the undisturbed soil is no more than 10%.

[0015] The advantages of this invention are:

[0016] (1) The roadbed at the junction adopts the solidified soil technology to form a solidified soil transition layer structure similar to a "board", which is more conducive to ensuring the integrity and stability of both sides of the junction and effectively reducing uneven settlement.

[0017] (2) The main materials of the solidified soil transition layer structure are existing soil and solidifying agent. The types of materials are relatively few, and the materials are readily available locally, which is environmentally friendly and saves costs.

[0018] (3) The main machinery is basically the same as the roadbed treatment machinery, and the technology is mature and construction is convenient;

[0019] (4) Reduce the laying of geotextiles, reduce the number of procedures, and save construction time;

[0020] (5) For roads of different grades and with different traffic volume requirements, the length and thickness of the solidified soil transition layer can be adjusted to meet the connection requirements, making the design and construction more flexible. Attached Figure Description

[0021] Figure 1 This invention is applied to the roadbed treatment at the cut-fill junction of a newly constructed road (the connection between the cut-fill junction in the longitudinal (parallel to the driving direction) and transverse (perpendicular to the driving direction) directions of the newly constructed road (the thickness of the solidified soil transition layer is ∈ [0.8m, 1.0m]).

[0022] Figure 2 This invention is applied to the roadbed treatment at the cut-fill junction of a newly constructed road (the connection between the cut-fill junction in the longitudinal (parallel to the driving direction) and transverse (perpendicular to the driving direction) directions of the newly constructed road (the thickness of the solidified soil transition layer is ∈ [1.2m, 2.0m]).

[0023] Figure 3 This invention is applied to the cross-sectional view of the roadbed treatment at the junction of the old and new sections of the reconstructed road (the connection at the transverse (perpendicular to the driving direction) section of the reconstructed road (the thickness of the solidified soil transition layer ∈ [0.8m, 1.0m]).

[0024] Figure 4 This invention is applied to the cross-sectional view of the roadbed treatment at the junction of the old and new roads in the reconstruction (the connection of the transverse (perpendicular to the driving direction) of the reconstruction and expansion road (the thickness of the solidified soil transition layer is ∈ [1.2m, 2.0m]). Detailed Implementation

[0025] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art:

[0026] like Figures 1-4 As shown in the figure, each of the markings represents: First solidified soil transition layer 1, First embankment 2, First drainage blind ditch 3, First impermeable geotextile 4, Second impermeable geotextile 5, Second solidified soil transition layer 6, Third solidified soil transition layer 7, Second embankment 8, Second drainage blind ditch 9, Third impermeable geotextile 10, Fourth impermeable geotextile 11.

[0027] 12. Fourth solidified soil transition layer; 13. Third embankment subgrade; 14. Third drainage blind ditch; 15. Fifth impermeable geotextile; 16. Sixth impermeable geotextile; 17. Fifth solidified soil transition layer; 18. Sixth solidified soil transition layer; 19. Fourth embankment subgrade; 20. Fourth drainage blind ditch; 21. Seventh impermeable geotextile; 22. Eighth impermeable geotextile.

[0028] 23. Ground line; 24. Road surface structure; 25. Existing road surface structure; 26. Widened road surface structure; 27. Existing road slope; A. Excavation section; B. Fill section; C. Existing road; D. Widened road.

[0029] Example: Figures 1 to 4As shown, the roadbed connection method based on solidification technology in this embodiment is used for the connection between two different roadbeds, including the cut-fill junction of newly built roads and the junction of old and new roads in reconstruction and expansion projects. The main principle is to lay a solidified soil transition layer similar to a "slab" at the junction of different roadbeds. The main materials of the solidified soil transition layer are undisturbed soil and solidifying agent. The organic matter content of the undisturbed soil or the treated undisturbed soil should not exceed 10%, and the moisture content and other indicators must meet the requirements of the selected solidifying agent.

[0030] In this embodiment, the solidified soil transition layer exhibits higher integrity and stability than typical roadbeds. Its thickness covers the entire working area of ​​the roadbed, meaning the load at the junction is primarily borne by the solidified soil transition layer. According to the theory of elastic homogeneous half-space roadbeds, the working area for medium and small vehicle roadbeds is approximately 0.9m-1.3m, and for large vehicle roadbeds, it is approximately 1.6m-2.4m. According to the "Highway Roadbed Design Specification" (JTG D30), generally, the thickness of the roadbed (working area) for light, medium, and heavy traffic is 0.8m, and for extra-heavy and extremely heavy traffic roadbeds (working area) it is 1.2m. This embodiment comprehensively considers the theory of elastic homogeneous half-space roadbeds, relevant roadbed specifications, and economic considerations, and rationally selects the thickness of the solidified soil transition layer for two scenarios: low-grade roads or roads with low traffic volume, and high-grade roads or roads with high traffic volume. The length of the solidified soil transition layer is taken as the length and width of the largest common vehicle on the road, i.e., a typical heavy truck, about 10m long and 3.0m wide. It is the length of the solidified soil transition layer in the longitudinal direction (parallel to the driving direction) and the transverse direction (perpendicular to the driving direction).

[0031] For the cut-fill junction of newly constructed roads, a longitudinally extending solidified soil transition layer needs to be laid at the cut-fill junction along the driving direction, i.e., between cut section A and fill section B, and a laterally extending solidified soil transition layer needs to be laid at the cut-fill junction perpendicular to the driving direction.

[0032] The design of the solidified soil transition layer for solidified soil subgrade is as follows: (1) For low-grade roads or roads with small traffic volumes, a solidified soil transition layer shall be laid together for the excavated and embanked sections after over-excavation. The solidified soil transition layer shall be located at the subgrade, with a thickness of not less than 0.8m and not more than 1.0m. The longitudinal solidified soil transition layer should be 10m long, and the transverse solidified soil transition layer should be 3m long. (2) For high-grade roads or roads with large traffic volumes, a solidified soil transition layer shall be laid together for the excavated and embanked sections after over-excavation. The solidified soil transition layer shall be located at the subgrade, with a thickness of not less than 1.2m and not more than 2.0m. The longitudinal solidified soil transition layer should be 10m long, and the transverse solidified soil transition layer should be 3m long. (3) The thickness of the solidified soil transition layer for special vehicles or special traffic sections shall be in accordance with the "Specifications for Design of Highway Subgrade" (JTG). (4) The solidified soil transition layer is backfilled and compacted in layers, with each layer not exceeding 0.3m in thickness; (5) When the thickness of the solidified soil transition layer exceeds 1m, steps are constructed according to the cut-fill boundary line, with a step height not exceeding 1m and a step length preferably 1m; at this time, one end of the solidified soil transition layer is partially overlapped on the step to ensure effective load transfer; (6) In areas with high precipitation, a seepage-proof pavement structure is adopted, and a seepage-proof geotextile is laid on the top surface of the solidified soil transition layer; (7) In areas with high groundwater levels, drainage blind ditches or blind pipes are set in the solidified soil transition layer, and a seepage-proof geotextile is laid under the solidified soil transition layer. The fill roadbed is filled with materials with good permeability; (8) When the original soil is poor roadbed soil, the original soil can be treated before the roadbed and solidified soil transition layer can be constructed.

[0033] For the junction of the old and new roads in the reconstruction and expansion project, namely between the original road C and the widened road D, the design of the transverse solidified soil transition layer of the solidified soil subgrade is as follows: (1) For low-grade roads or roads with small traffic volume, the solidified soil transition layer is set at the subgrade, with a thickness of not less than 0.8m and not more than 1.0m, and a length preferably of 3m; (2) For high-grade roads or roads with large traffic volume, the solidified soil transition layer is set at the subgrade, with a thickness of not less than 1.2m and not more than 2.0m, and a length preferably of 3m; (3) The thickness of the solidified soil transition layer for special vehicles or special traffic sections should be in accordance with the "Specifications for Design of Highway Subgrade" (JTG). (4) The solidified soil transition layer is backfilled and compacted in layers, with each layer not exceeding 0.3m in thickness; (5) When the thickness of the solidified soil transition layer exceeds 1m, steps are constructed according to the boundary between the old and new road surfaces. The height of the steps does not exceed 1m, and the length of the steps should be 1m. At this time, one end of the solidified soil transition layer is partially overlapped on the steps to ensure the effective transfer of load; (6) The overlap is made at the junction of the old and new road surfaces to prevent water seepage to the solidified soil transition layer of the road surface; depending on the groundwater level, drainage blind ditches or blind pipes and anti-seepage geotextiles can be set in the solidified soil transition layer; (7) When the original soil of the reconstructed and expanded road section is poor roadbed soil, the original soil can be treated before the roadbed and solidified soil transition layer can be constructed.

[0034] Based on the design method of this embodiment, a structure is formed as follows: Figures 1 to 4 The four scenarios are as follows:

[0035] Example 1: Figure 1 As shown, this example provides a treatment method for a solidified soil transition layer (solidified soil transition layer thickness ∈ [0.8m, 1.0m]) at the junction of fill and cut roadbeds in the longitudinal (parallel to the driving direction) and transverse (perpendicular to the driving direction) directions of newly built roads. The main structure includes a first solidified soil transition layer 1, a first fill roadbed 2, a first drainage blind ditch 3, a first impermeable geotextile 4, and a second impermeable geotextile 5. The specific indicators and parameters are shown in Table 1 below.

[0036] Table 1 Technical indicators and parameters of solidified soil transition layer

[0037]

[0038] Among them, the soil used in the solidified soil transition layer meets the requirements of the corresponding solidifying agent, each layer is uniformly mixed, spread and compacted, and the curing time is ≥7 days; ② The thickness of the solidified soil transition layer should be further determined by calculating the subgrade working area according to the specifications.

[0039] Example 2: Figure 2 As shown, this example provides a method for treating the solidified soil transition layer (solidified soil transition layer thickness ∈ [1.2m, 2.0m]) at the junction of fill and cut roadbeds in the longitudinal (parallel to the driving direction) and transverse (perpendicular to the driving direction) directions of newly constructed roads. The main structure includes a second solidified soil transition layer 6, a third solidified soil transition layer 7, a roadbed fill 8, a second drainage blind ditch 9, a third impermeable geotextile 10, and a fourth impermeable geotextile 11. The specific indicators and parameters are shown in Table 2 below.

[0040] Table 2 Technical Indicators and Parameters of Solidified Soil Transition Layer

[0041]

[0042] Among them, the soil used in the solidified soil transition layer meets the requirements of the corresponding solidifying agent, each layer is uniformly mixed, spread and compacted, and the curing time is ≥7 days; ② The thickness of the solidified soil transition layer should be further determined by calculating the subgrade working area according to the specifications.

[0043] Example 3: Figure 3 As shown, this example provides a treatment method for a solidified soil transition layer (solidified soil transition layer thickness ∈ [0.8m, 1.0m]) at the junction of the old and new roadbeds in the transverse (perpendicular to the driving direction) direction of road reconstruction and expansion. The main structure includes the fourth solidified soil transition layer 12, the third embankment roadbed 13, the third drainage blind ditch 14, the fifth impermeable geotextile 15, and the sixth impermeable geotextile 16. The specific indicators and parameters are shown in Table 3 below.

[0044] Table 3 Technical indicators and parameters of solidified soil transition layer

[0045]

[0046] Among them, the soil used in the solidified soil transition layer meets the requirements of the corresponding solidifying agent, each layer is uniformly mixed, spread and compacted, and the curing time is ≥7 days; ② The thickness of the solidified soil transition layer should be further determined by calculating the subgrade working area according to the specifications.

[0047] Example 4: Figure 4 As shown, this example provides a treatment method for the solidified soil transition layer (solidified soil transition layer thickness ∈ [1.2m, 2.0m]) of the new and old roadbeds in the transverse (perpendicular to the driving direction) direction of road reconstruction and expansion. The main structure includes the fifth solidified soil transition layer 17, the sixth solidified soil transition layer 18, the roadbed fill 19, the fourth drainage blind ditch 20, the seventh impermeable geotextile 21 and the eighth impermeable geotextile 22. The specific indicators and parameters are shown in Table 4 below.

[0048] Table 4 Technical Indicators and Parameters of Solidified Soil Transition Layer

[0049]

[0050] Among them, the soil used in the solidified soil transition layer meets the requirements of the corresponding solidifying agent, each layer is uniformly mixed, spread and compacted, and the curing time is ≥7 days; ② The thickness of the solidified soil transition layer should be further determined by calculating the subgrade working area according to the specifications.

[0051] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.

Claims

1. A roadbed connection method based on solidification technology, used for connecting two different roadbeds, the two roadbeds including a first roadbed and a second roadbed, characterized in that: Including the following methods: Based on the working area of ​​the roadbed at the junction between the first roadbed and the second roadbed, a solidified soil transition layer is set between them, and the solidified soil transition layer covers the working area of ​​the roadbed. Based on the expected load above the first roadbed and the second roadbed, the range and number of layers of the solidified soil transition layer are designed. The range of the solidified soil transition layer refers to the length of the solidified soil transition layer extending into the first roadbed or the second roadbed, with one end located at the first roadbed and the other end at the second roadbed. The number of layers of the solidified soil transition layer refers to the provision of one or more solidified soil transition layers between the first roadbed and the second roadbed along the height direction of the roadbed. A stepped structure is constructed between the first roadbed and the second roadbed, with the height of each step matching the thickness of the solidified soil transition layer, and one end of the solidified soil transition layer being placed on the step. The overall thickness of the solidified soil transition layer is achieved by superimposing the corresponding solidified soil transition layer on each of the stepped steps.

2. The roadbed connection method based on solidification technology according to claim 1, characterized in that: The solidified soil transition layer is backfilled and compacted in layers, with each layer not exceeding 0.3m in thickness.

3. The roadbed connection method based on solidification technology according to claim 1, characterized in that: A seepage-proof geotextile is laid on the top surface of the solidified soil transition layer to form a seepage-proof pavement structure.

4. The roadbed connection method based on solidification technology according to claim 1, characterized in that: An impermeable geotextile is laid on the bottom surface of the solidified soil transition layer and a drainage ditch or blind pipe is installed inside. At the same time, the embankment is filled with permeable materials.

5. The roadbed connection method based on solidification technology according to claim 1, characterized in that: The solidified soil transition layer includes undisturbed soil and a solidifying agent, wherein the organic matter content of the undisturbed soil is no more than 10%.

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