Method for classifying highway subgrade layer structure and application thereof

Abstract

The present application relates to the technical field of geological exploration, in particular to a method for classifying highway roadbed stratum structure and application; the method comprises the following steps: S1, obtaining the thickness of different soil bodies in the highway roadbed stratum, the position relationship of the soil bodies in the stratum and the permeability coefficient of the soil bodies; S2, constructing the roadbed stratum structure according to the thickness of different soil bodies in the highway roadbed stratum and the position relationship in the stratum; classifying the soil bodies according to the permeability coefficient; S3, converting the soil bodies in the roadbed stratum structure into soil layers according to the permeability of adjacent soil bodies in the roadbed stratum structure, and classifying the soil layers; S4, classifying the roadbed stratum structure according to the distribution of different types of soil layers in the roadbed stratum structure; the method provides theoretical support for the selection and design of drainage structures, and makes the design of highway roadbed drainage structure simpler, more reasonable and more efficient.

Description

Technical Field

[0001] This invention relates to the field of geological surveying technology, specifically to the surveying technology of roadbed structures, and particularly to a method and application for classifying the geological structure of highway roadbeds. Background Technology

[0002] Water is one of the main causes of damage to highways and roadside structures. It can soften, erode, and even destroy roadbeds, leading to hazards such as slope collapses and road frost heave. Water that harms roads can be divided into surface water and groundwater. Surface water is mainly runoff from rainstorms and snow cover. Groundwater is water that exists in the pores of rocks below the ground. Based on its location, groundwater can be further divided into perched water (water that seeps into the soil from the surface but does not reach the lower layers), unconfined water (water in aquifers above the first impermeable layer below the ground, which flows along the soil under gravity due to its proximity to the surface), and interlayer water (groundwater in aquifers between any two impermeable layers below the ground, which can emerge to the surface as springs when the water source is above the ground level). Therefore, in order to reduce or even avoid the damage caused by water to road facilities, the issue of road drainage must be considered during the design and construction of roads. Road drainage facilities are road ancillary structures designed for road drainage and are the most direct and effective means of improving and solving the damage caused by water to roads.

[0003] Depending on the type of hazardous road water to be eliminated, road drainage structures can be divided into roadbed surface drainage facilities and roadbed groundwater drainage facilities. Roadbed surface drainage facilities are designed to quickly remove road surface and surface runoff, prevent water accumulation, lower excessively high groundwater levels, and remove water that has seeped into the road structure and roadbed, thus ensuring roadbed stability, extending road surface service life, maintaining normal traffic and safety for vehicles and pedestrians, and keeping roads clean and hygienic. Roadbed surface drainage facilities include structures such as side ditches, intercepting ditches, drainage ditches, drop troughs and rapid flow channels, aqueducts, inverted siphons, and sump basins. Roadbed groundwater drainage facilities, on the other hand, are underground drainage facilities designed to intercept, collect, and remove water flowing towards the roadbed or lower the groundwater level, including structures such as culverts, infiltration ditches, and infiltration wells. However, the road drainage structure of the auxiliary roadbed, regardless of its structure, type, location and / or drainage function, will have different layout requirements or construction forms due to differences in terrain, geological structure and region. Therefore, only road drainage structures designed specifically according to the regional characteristics and topographic features of the road can achieve higher drainage efficiency, lower construction costs and less impact on the environment. This is also something that must be considered in the design and construction of road drainage structures today.

[0004] In the design of road drainage structures, geological structure is one of the important factors affecting the design. Currently, a lot of research has been done on geological structure in building foundation pits, dam water conservancy drainage, etc., and geological structure has been classified in a targeted manner according to its design and construction requirements. However, the existing geological classification is not suitable for the design and construction of highway subgrade drainage structures. Therefore, there is an urgent need for a method to classify geological structure in a targeted manner according to the design and construction requirements of highway subgrade drainage structures. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem that existing geological structure classification methods are not suitable for the design and construction of highway subgrade drainage structures, and to provide a method and application for classifying the geological structure of highway subgrades.

[0006] This invention provides a method for classifying the subgrade structure of highways, comprising the following steps:

[0007] S1. Obtain the thickness of different soil bodies in the roadbed stratum, the positional relationship of the soil bodies in the stratum, and the permeability coefficient of the soil bodies;

[0008] S2. Construct the roadbed stratum structure based on the thickness of different soil bodies and their positional relationship in the strata.

[0009] Soil is classified according to its permeability based on its permeability coefficient; the soil is divided into permeable soil and impermeable soil.

[0010] S3. Based on the permeability of adjacent soils in the roadbed stratum structure, the soils in the roadbed stratum structure are converted into soil layers, and the soil layers are classified; the soil layers are divided into permeable soil layers and impermeable soil layers;

[0011] S4. Based on the distribution of different types of soil layers in the roadbed stratum, the roadbed stratum is classified into permeable stratum and impermeable stratum.

[0012] This invention provides a method for classifying the subgrade structure of highways. Based on the subgrade structure and the thickness, positional relationship, and permeability characteristics of the soil within the subgrade stratum, the method classifies the subgrade structure, thus providing theoretical support for the selection and design of drainage structures. This makes the design of highway subgrade drainage structures simpler, more reasonable, and more efficient, thereby saving construction costs and shortening the construction period while ensuring drainage performance. This method has good universality and practicality, and is suitable for large-scale application in highway surveying and design.

[0013] In step S1, the method for obtaining the thickness of different soil bodies in the roadbed strata and the positional relationship of the soil bodies in the strata includes at least one of geological exploration, geological survey, remote sensing technology, geophysical survey and geochemical exploration.

[0014] Preferably, the soil type is silty clay, humus, peat soil, silty mud soil, pebbles, weathered slate, gravel, weathered shale, or Changbai sandstone.

[0015] Preferably, the permeability coefficient of the soil is obtained through a permeability coefficient test; the specific test standard is in accordance with JTG3430-2020 "Specifications for Geotechnical Testing of Highways"; the permeability coefficient obtained through the permeability coefficient test is more accurate and facilitates the accurate classification of soil permeability.

[0016] Preferably, the permeability coefficient includes both vertical and horizontal permeability coefficients; the preferred permeability coefficient can better assess the permeability of the soil, thereby enabling a more reasonable classification of the geological structure.

[0017] In step S2, preferably, the vertical permeability coefficient and / or horizontal permeability coefficient of the permeable soil satisfy the following:

[0018] , and / or ;

[0019] The vertical and horizontal permeability coefficients of the impermeable soil satisfy the following:

[0020] ;

[0021] Where a is the vertical permeability coefficient, b is the horizontal permeability coefficient, and q is the design rainfall intensity (L / s·hm). 2 ); y is the runoff coefficient, which is 0.3; F is the catchment area (hm²). 2 K is the correction factor, which is 0.05.

[0022] If the permeability coefficient is too low, the soil will seep water slowly, resulting in an underestimation of the drainage effect of the designed drainage structure. As a result, water in the roadbed cannot be drained in time, which will cause damage to the roadbed. If the permeability coefficient is too high, the drainage effect of the soil will be underestimated, which will require the design of a more complex and efficient drainage structure, thus wasting resources and construction costs.

[0023] The criteria for classifying permeable and impermeable soils are determined based on the roadbed structure and the soil characteristics of the region. The permeability of soil directly affects the overall efficiency of the drainage system. Soil with good permeability can more effectively infiltrate and drain water, reducing surface runoff and soil erosion. In contrast, in soil with poor permeability, water is not easily drained, which may lead to water accumulation, increase soil moisture, and affect the stability of the roadbed. The optimal classification criteria can better achieve the drainage effect of the roadbed structure and significantly reduce the damage of water bodies to the roadbed.

[0024] Preferably, the designed rainfall intensity is: ;

[0025] Where: q is the design rainfall intensity; P is the design rainfall recurrence period; t is the rainfall duration; A1 is the rainfall force parameter; C is the rainfall force variation parameter; b is the rainfall duration correction parameter; and n is the rainfall attenuation index.

[0026] In step S3, the preferred method for converting soil in the roadbed stratum structure into soil layers is as follows: adjacent soils in the roadbed stratum structure are classified into the same soil layer if they have the same permeability classification; if adjacent soils have different permeability classifications, they are classified into different soil layers.

[0027] Preferably, the soil layers are classified according to the type of soil body that constitutes them; soil layers composed of permeable soil bodies are permeable soil layers, and soil layers composed of impermeable soil bodies are impermeable soil layers.

[0028] Preferably, the permeable soil layer contains at least one layer of permeable soil; the impermeable soil layer contains at least one layer of impermeable soil.

[0029] In step S4, preferably, the permeable stratum structure contains at least one permeable soil layer with a thickness of not less than 3m, and the upper surface of the permeable soil layer is no more than 10m below the ground surface; the permeable stratum structure contains a permeable soil layer that can quickly infiltrate water, so that only a simple drainage structure needs to be used to connect and cooperate with the permeable soil layer to achieve the need for fast and effective drainage.

[0030] Preferably, in the impermeable stratum structure, the thickness of the permeable soil layer is less than 3m;

[0031] Or the upper surface of a permeable soil layer with a thickness of not less than 3m is more than 10m below the ground surface;

[0032] Or it may contain only impermeable soil layers;

[0033] In impermeable strata, the soil layers have poor permeability or are too deep, and simple drainage structures alone cannot achieve rapid and effective drainage. Drainage structures need to be designed and constructed specifically according to the specific soil structure.

[0034] In step S4, preferably, the method further includes: classifying the permeable stratum structure according to the thickness and positional relationship between the permeable soil layer and the impermeable soil layer in the permeable stratum structure; the permeable stratum structure is divided into upper permeable stratum structure, middle permeable stratum structure and lower permeable stratum structure; further classifying the permeable stratum structure can better and more accurately achieve the coordination between the stratum structure and the drainage method, thereby improving the drainage effect and reducing the cost.

[0035] Preferably, in the upper permeable stratum structure, the permeable soil layer is located at the top of the stratum structure and has a thickness of not less than 3m;

[0036] In the aforementioned permeable stratum structure, the impermeable soil layer is located at the top of the stratum structure and its thickness is no more than 3m.

[0037] At the same time, the permeable soil layer is close to the uppermost impermeable soil layer, and its thickness is not less than 3m;

[0038] In the lower permeable stratum structure, the impermeable soil layer is located at the top of the stratum structure and has a thickness greater than 3m but not greater than 10m. The permeable soil layer is close to the top impermeable soil layer and has a thickness of not less than 3m.

[0039] Furthermore, the present invention also provides an application of a method for classifying the subgrade structure of highways in the design and construction of highway subgrade drainage structures.

[0040] By classifying the roadbed stratum structure, we can better design and construct drainage structures based on the roadbed stratum structure. This will help reduce design difficulty, improve drainage efficiency, save construction costs, reduce unreasonable damage to the stratum structure, and help protect the ecological environment of the roadside.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] 1. This invention provides a method for classifying the subgrade structure of highways. Based on the subgrade structure and the thickness, positional relationship, and permeability characteristics of the soil in the subgrade layer, the method classifies the subgrade structure of highways, thereby providing theoretical support for the selection and design of drainage structures.

[0043] 2. The present invention provides a method for classifying the subgrade structure of highways, which makes the design of highway subgrade drainage structures simpler, more reasonable, and more efficient. This allows for saving construction costs and shortening the construction period while ensuring drainage performance.

[0044] 3. The method for classifying the geological structure of highway subgrades in this invention has good universality and strong practicality, and is suitable for large-scale application in highway surveying and design. Attached Figure Description

[0045] Figure 1 This is a flowchart of a method for classifying the subgrade structure of a highway base in Example 1;

[0046] Figure 2 This is a classification result diagram of the subgrade structure of a highway base in Example 1;

[0047] Figure 3 This is a classification diagram of the substructure of a highway base in Example 1. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0049] Example 1

[0050] The method of this invention is used to classify the roadbed layer structure of a certain highway (the process is as follows). Figure 1 (As shown), the specific steps are as follows:

[0051] S1. Using a combination of geological exploration, geological survey, and remote sensing technology, obtain the thickness of different soil types in the roadbed strata (the surveyed soil types for the entire road section include: silty clay, humus, peat soil, silty mud, pebbles, weathered slate, gravel, weathered shale, and Changbai sandstone), the positional relationship of the soil types in the strata, and the permeability coefficient of the soil types (refer to JTG 3430-2020, including vertical permeability coefficient and horizontal permeability coefficient).

[0052] S2. Construct the roadbed stratum structure based on the thickness of different soil bodies and their positional relationship in the strata.

[0053] Soil is classified according to its permeability based on its permeability coefficient; soil is divided into permeable soil and impermeable soil; the vertical permeability coefficient (a) and / or horizontal permeability coefficient (b) of permeable soil satisfy the following:

[0054] , and / or ;

[0055] The vertical and horizontal permeability coefficients of the impermeable soil satisfy the following:

[0056] ;

[0057] Where q is the design rainfall intensity (L / s·hm) 2 ); y is the runoff coefficient, which is 0.3; F is the catchment area (hm²). 2 K is the correction factor, which is 0.05.

[0058] Design rainfall intensity for this region: ;

[0059] Where: q is the design rainfall intensity; P is the design rainfall recurrence period; t is the rainfall duration;

[0060] S3. Based on the permeability of adjacent soil masses in the roadbed stratum structure, the soil masses in the roadbed stratum structure are converted into soil layers, and the soil layers are classified. The soil layers are divided into permeable soil layers and impermeable soil layers. The method for converting soil masses in the roadbed stratum structure into soil layers is as follows: adjacent soil masses in the roadbed stratum structure are classified into the same soil layer if they have the same permeability classification; if adjacent soil masses have different permeability classifications, they are classified into different soil layers. The method for classifying soil layers is as follows: the soil layers are classified according to the type of soil masses that make up the soil layers; soil layers composed of permeable soil masses are permeable soil layers, and soil layers composed of impermeable soil masses are impermeable soil layers.

[0061] S4. Based on the distribution of different types of soil layers in the roadbed stratum, the roadbed stratum structure is classified; the roadbed stratum structure is divided into permeable stratum structure and impermeable stratum structure;

[0062] The permeable stratum structure contains at least one permeable soil layer with a thickness of not less than 3m, and the upper surface of the permeable soil layer is no more than 10m below the ground surface.

[0063] In impermeable strata structures, the thickness of permeable soil layers is less than 3m; or the upper surface of permeable soil layers with a thickness of not less than 3m is more than 10m below the ground surface; or the structure contains only impermeable soil layers.

[0064] Furthermore, based on the thickness and positional relationship between permeable and impermeable soil layers in the permeable stratum structure, the permeable stratum structure is further classified; the permeable stratum structure is divided into upper permeable stratum structure, middle permeable stratum structure, and lower permeable stratum structure.

[0065] In the upper permeable stratum structure, the permeable soil layer is located at the top of the stratum structure and has a thickness of not less than 3m;

[0066] In the middle permeable stratum structure, the impermeable soil layer is located at the top of the stratum structure and its thickness is no more than 3m. At the same time, the permeable soil layer is close to the top impermeable soil layer and its thickness is no less than 3m.

[0067] In the lower permeable stratum structure, the impermeable soil layer is located at the top of the stratum structure and has a thickness greater than 3m but not greater than 10m. The permeable soil layer is close to the top impermeable soil layer and has a thickness of not less than 3m.

[0068] The classification results of the geological structure of a certain highway base are shown in Table 1. Figure 2 , Figure 3 As shown:

[0069] Table 1 Classification results of the subgrade structure of a certain highway.

[0070]

[0071]

[0072] Example 2

[0073] This paper presents an application of a method for classifying the geological structure of highway subgrade in the design and construction of highway subgrade drainage structures. Based on the classification of subgrade geological structures in Example 1 and the characteristics of the corresponding types of geological structures, highway designers can selectively design drainage facilities for a specific highway subgrade. This reduces design complexity, improves drainage efficiency, saves construction costs, minimizes unreasonable damage to the geological structure during construction, and contributes to the protection of the roadside ecological environment.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for classifying the subgrade structure of highways, characterized in that, Includes the following steps: S1. Obtain the thickness of different soil bodies in the roadbed stratum, the positional relationship of the soil bodies in the stratum, and the permeability coefficient of the soil bodies, wherein the permeability coefficient includes the vertical permeability coefficient and the horizontal permeability coefficient; S2. Construct the roadbed stratum structure based on the thickness of different soil bodies and their positional relationship in the strata. Soil is classified according to its permeability based on its permeability coefficient; the soil is divided into permeable soil and impermeable soil; the vertical permeability coefficient and / or horizontal permeability coefficient of the permeable soil satisfy the following: , and / or ; The vertical and horizontal permeability coefficients of the impermeable soil satisfy the following: ； Where a is the vertical permeability coefficient, b is the horizontal permeability coefficient, q is the design storm intensity, y is the runoff coefficient, F is the catchment area, and K is the correction factor. The designed rainfall intensity: ; Where: q is the design rainfall intensity; P is the design rainfall return period; t is the rainfall duration; A1 is the rainfall intensity parameter; C is the rainfall intensity variation parameter; b is the rainfall duration correction parameter; n is the rainfall attenuation index; S3. Based on the permeability of adjacent soils in the roadbed stratum structure, the soils in the roadbed stratum structure are converted into soil layers, and the soil layers are classified; the soil layers are divided into permeable soil layers and impermeable soil layers. S4. Based on the distribution of different types of soil layers in the roadbed stratum, the roadbed stratum is classified into permeable stratum and impermeable stratum.

2. The method for classifying the roadbed layer structure according to claim 1, characterized in that, In step S1, the methods for obtaining the thickness of different soil bodies in the roadbed strata and the positional relationship of the soil bodies in the strata include at least one of geophysical survey and geochemical survey.

3. The method for classifying the roadbed subgrade structure according to claim 1, characterized in that, In step S3, the method for converting the soil in the roadbed stratum structure into soil layers is as follows: Adjacent soil layers in the roadbed stratum are classified as the same soil layer if they have the same permeability classification. If adjacent soil layers have different permeability classifications, they are classified as different soil layers.

4. The method for classifying the roadbed subgrade structure according to claim 1, characterized in that, The method for classifying the soil layers is as follows: Classification is based on the composition and type of soil layers; A soil layer composed of permeable soil is called a permeable soil layer, and a soil layer composed of impermeable soil is called an impermeable soil layer. The permeable soil layer contains at least one layer of permeable soil. The impermeable soil layer contains at least one layer of impermeable soil.

5. The method for classifying the roadbed subgrade structure according to claim 1, characterized in that, In step S4, the permeable stratum structure contains at least one permeable soil layer with a thickness of not less than 3m, and the upper surface of the permeable soil layer is no more than 10m below the ground surface. In the impermeable stratum structure, the thickness of the permeable soil layer is less than 3m; Alternatively, the upper surface of a permeable soil layer with a thickness of not less than 3m is more than 10m below the ground surface; Or, it may contain only impermeable soil layers.

6. The method for classifying the roadbed layer structure according to claim 1, characterized in that, Step S4 also includes: further classifying the permeable strata structure according to the thickness and positional relationship between the permeable soil layer and the impermeable soil layer in the permeable strata structure; The permeable strata structure is divided into upper permeable strata structure, middle permeable strata structure and lower permeable strata structure.

7. The method for classifying the roadbed layer structure according to claim 6, characterized in that, In the aforementioned upper permeable stratum structure, the permeable soil layer is located at the top of the stratum structure and has a thickness of not less than 3m; In the aforementioned permeable stratum structure, the impermeable soil layer is located at the top of the stratum structure and has a thickness of no more than 3m. Meanwhile, the permeable soil layer is adjacent to the top impermeable soil layer and has a thickness of no less than 3m. In the lower permeable stratum structure, the impermeable soil layer is located at the top of the stratum structure and has a thickness greater than 3m but not greater than 10m. The permeable soil layer is close to the top impermeable soil layer and has a thickness of not less than 3m.

8. The method for classifying the subgrade structure of a highway subgrade as described in any one of claims 1-7 is applied in the design and construction of highway subgrade drainage structures.

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