A method for screening drainage modes based on highway roadbed layer structure

Abstract

The present application relates to the technical field of engineering design, in particular to a kind of based on highway subgrade stratum structure drainage mode screening method;The method comprises the following steps: S1, obtaining the stratum structure type of highway subgrade;S2, according to stratum structure type, obtain different stratum structure parameters;S3, according to the stratum structure parameter selected corresponding drainage mode of acquisition;The method of the present application is according to the stratum structure characteristics of different types of highway subgrade, and the drainage principle, structure characteristics and drainage effect of drainage structure, the drainage mode of highway subgrade is screened and matched, so that the drainage mode is more suitable for stratum structure, while ensuring the drainage effect, significantly reduce the engineering quantity and construction cost when the construction of drainage structure, shorten the engineering time, also reduce the damage degree of drainage structure to stratum, be conducive to realizing the protection to road environment.

Description

Technical Field

[0001] This invention relates to the field of road design methods, specifically to the selection of road drainage methods, and particularly to a method for selecting drainage methods based on the roadbed subgrade structure. Background Technology

[0002] Water is one of the main causes of damage to highways and roadside structures. 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] Road drainage structures are divided into roadbed surface drainage facilities and roadbed groundwater drainage facilities. 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 include structures such as culverts, infiltration ditches, and infiltration wells. Road drainage structures designed specifically according to the regional characteristics and topographic features of the road will achieve higher drainage efficiency and lower construction costs, which is a common consideration in the design and construction of road drainage structures today. However, in the selection of road drainage methods, the geological structure is also an important factor affecting the selection of road drainage methods, and there is currently no record of methods for selecting drainage methods based on the geological structure of the highway roadbed. Summary of the Invention

[0004] The purpose of this invention is to propose a method for screening drainage methods based on the roadbed subgrade structure.

[0005] This invention provides a method for selecting drainage methods based on the roadbed subgrade structure, comprising the following steps:

[0006] S1. Obtain the geological structure type of the highway subgrade;

[0007] S2. Obtain different stratigraphic parameters according to the stratigraphic structure type;

[0008] S3. Select the corresponding drainage method based on the obtained geological structure parameters.

[0009] This invention provides a method for selecting drainage methods based on the geological structure of highway subgrades. According to the geological structure characteristics of different types of highway subgrades, as well as the drainage principles, structural characteristics, and drainage effects of drainage structures, the method selects and matches drainage methods for highway subgrades. This makes the drainage methods more suitable for the geological structure, ensuring drainage effectiveness while significantly reducing the amount of engineering work and construction costs during drainage structure construction, shortening the project time, and reducing the degree of damage to the geological structure caused by the drainage structure, thus contributing to the protection of the roadside ecological environment.

[0010] In step S1, a preferred method for obtaining the geological structure type of the roadbed includes:

[0011] S101. 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;

[0012] S102. Construct the roadbed stratum structure based on the thickness of different soil bodies and their positional relationship in the strata.

[0013] Soil is classified according to its permeability based on its permeability coefficient; the soil is divided into permeable soil and impermeable soil.

[0014] S103. 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.

[0015] S104. 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.

[0016] Preferably, the geological structure type includes impermeable geological structure, upper permeable geological structure, middle permeable geological structure and lower permeable geological structure.

[0017] Preferably, in the impermeable stratum structure, the thickness of the permeable soil layer is less than 3m;

[0018] 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;

[0019] Or it may contain only impermeable soil layers; 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;

[0020] 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.

[0021] 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.

[0022] Preferably, the permeable soil layer consists of at least one layer of permeable soil; the impermeable soil layer consists of at least one layer of impermeable soil.

[0023] Preferably, the vertical permeability coefficient (a) and / or horizontal permeability coefficient (b) of the permeable soil satisfy:

[0024] and / or

[0025] The vertical and horizontal permeability coefficients of the impermeable soil satisfy the following:

[0026] and

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Preferably, the design rainfall intensity

[0031] The designed rainfall intensity:

[0032] 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.

[0033] In step S2, preferably, the geological structure parameters include: the soil type of the impermeable soil layer in the upper permeable stratum structure; the thickness of the uppermost impermeable soil layer in the middle or lower permeable stratum structure; and the soil type and thickness of the uppermost impermeable soil layer in the impermeable stratum structure.

[0034] Preferably, the soil type is soft soil or rock soil; the soft soil is a special type of soil, mainly composed of silt deposits with high natural water content, high compressibility, low bearing capacity and a small amount of humus, and is usually gray in appearance, with high natural porosity and high natural water content; the soft soil includes at least one of silty clay, humus soil, peat soil and silty soil.

[0035] Preferably, the rock and soil refers to granular material formed by natural processes such as rock weathering, erosion, transportation and deposition; the rock and soil includes at least one of weathered slate, weathered shale and Changbai sandstone.

[0036] In step S3, preferably, the specific criteria for selecting the corresponding drainage method based on the obtained geological structure parameters are as follows:

[0037] When the stratum structure is an upper permeable stratum structure and the soil type of the impermeable soil layer is rock and soil, a drainage method combining horizontal drainage blind pipes and seepage blind ditches is selected in the upper permeable soil layer.

[0038] When the stratum structure is a permeable upper stratum and the soil type of the impermeable soil layer is soft soil, a drainage method combining blind ditches and infiltration ditches is selected in the permeable upper soil layer.

[0039] When the geological structure is a middle-permeable stratum or a lower-permeable stratum, and the thickness of the uppermost impermeable soil layer is less than 3m, the method of setting up blind drains in the middle-permeable soil layer is selected.

[0040] When the geological structure is a middle-layer permeable stratum or a lower-layer permeable stratum, and the thickness of the uppermost impermeable soil layer is not less than 3m, the method of setting up blind drains in the upper impermeable soil layer shall be selected.

[0041] When the geological structure is impermeable, the method of setting up open ditches for drainage is chosen in the uppermost impermeable soil layer.

[0042] Preferably, in the upper permeable stratum structure, the permeable blind ditch is a drainage structure in which a permeable blind pipe is laid at the bottom of the blind ditch and coarse granular material is filled in the blind ditch for interception and drainage.

[0043] Preferably, in the upper permeable stratum structure, the seepage trench is divided into complete seepage trenches and incomplete seepage trenches; the complete seepage trench refers to the seepage trench that is excavated to the depth of the impermeable soil layer; the incomplete seepage trench refers to the seepage trench that is excavated to the depth of the permeable soil layer.

[0044] Preferably, in impermeable strata structures, the dimensions of the open ditch are related to the soil type and thickness of the uppermost impermeable soil layer.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] 1. This invention provides a method for screening drainage methods based on the geological structure of highway subgrade. According to the geological structure characteristics of different types of highway subgrade, as well as the drainage principle, structural characteristics and drainage effect of drainage structures, the drainage methods of highway subgrade are screened and matched, so that the drainage methods are more suitable for the geological structure.

[0047] 2. The drainage method selection method based on the roadbed stratum structure of the present invention ensures the drainage effect while significantly reducing the amount of engineering work and construction cost during the construction of drainage structures, shortening the engineering time, and reducing the degree of damage to the stratum caused by drainage structures, which is conducive to the protection of the road environment ecological environment. Attached Figure Description

[0048] Figure 1 This is a flowchart of the drainage method selection method based on the roadbed layer structure of a certain highway in Embodiment 1 of the present invention. Detailed Implementation

[0049] 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.

[0050] Example 1

[0051] The method of this invention is used to select road drainage methods based on the roadbed stratum structure of a certain highway. The specific steps (process as follows) are as follows: Figure 1 As shown below:

[0052] S1. Obtain the geological structure type of a certain highway subgrade, as shown in Table 1;

[0053] Table 1 Classification of the Subgrade Structure of a Certain Expressway

[0054]

[0055]

[0056] S2. Based on the type of geological structure, obtain different geological structure parameters; the geological structure parameters include: the soil type of the impermeable layer in the upper permeable geological structure; the thickness of the upper impermeable layer in the middle or lower permeable geological structure; and the soil type and thickness of the upper impermeable layer in the impermeable geological structure.

[0057] S3. The specific criteria for selecting the corresponding drainage method based on the obtained geological structure parameters are as follows:

[0058] When the stratum structure is an upper permeable stratum structure and the soil type of the impermeable soil layer is rock and soil, a drainage method combining horizontal drainage blind pipes and seepage blind ditches is selected in the upper permeable soil layer.

[0059] When the stratum structure is a permeable upper stratum and the soil type of the impermeable soil layer is soft soil, a drainage method combining blind ditches and infiltration ditches is selected in the permeable upper soil layer.

[0060] When the geological structure is a middle-permeable stratum or a lower-permeable stratum, and the thickness of the uppermost impermeable soil layer is less than 3m, the method of setting up blind drains in the middle-permeable soil layer is selected.

[0061] When the geological structure is a middle-layer permeable stratum or a lower-layer permeable stratum, and the thickness of the uppermost impermeable soil layer is not less than 3m, the method of setting up blind drains in the upper impermeable soil layer shall be selected.

[0062] When the geological structure is impermeable, the method of setting up open ditches for drainage is selected in the uppermost impermeable soil layer;

[0063] The results of the screening of drainage methods for a certain highway are shown in Table 2:

[0064] Table 2. Results of the selection of drainage methods for a certain expressway

[0065]

[0066]

[0067] By screening and matching the geological structure and drainage methods of different types of highway subgrades, the drainage methods are made more suitable for the geological structure. This ensures the drainage effect while significantly reducing the amount of engineering work and construction costs during the construction of drainage structures, shortening the project time, and reducing the degree of damage to the geological structure caused by the drainage structures. This is conducive to the protection of the roadside ecological environment.

[0068] 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 screening a drainage mode based on a highway roadbed layer structure, characterized by, The method comprises the following steps: S1, obtaining the stratum structure type of the road embankment; the stratum structure type comprises impermeable stratum structure, upper permeable stratum structure, middle permeable stratum structure and lower permeable stratum structure; In the impermeable stratum structure, the thickness of the permeable soil layer is less than 3m; or the depth of the upper surface of the permeable soil layer with a thickness not less than 3m from the ground is greater than 10m; or only impermeable soil layer is contained; In the upper permeable stratum structure, the permeable soil layer is located in the uppermost layer of the stratum structure, and the thickness is not less than 3m; In the middle permeable stratum structure, the impermeable soil layer is located in the uppermost layer of the stratum structure, and the thickness is not greater than 3m, and the permeable soil layer is close to the impermeable soil layer in the uppermost layer, and the thickness is not less than 3m; In the lower permeable stratum structure, the impermeable soil layer is located in the uppermost layer of the stratum structure, and the thickness is greater than 3m but not greater than 10m, and the permeable soil layer is close to the impermeable soil layer in the uppermost layer, and the thickness is not less than 3m; S2, obtaining different stratum structure parameters according to the stratum structure type; the stratum structure parameters comprise: The soil type of the impermeable soil layer in the upper permeable stratum structure; The thickness of the impermeable soil layer in the uppermost layer of the middle permeable stratum structure or the lower permeable stratum structure; The soil type and thickness of the impermeable soil layer in the uppermost layer of the impermeable stratum structure; S3, selecting the corresponding drainage mode according to the obtained stratum structure parameters; the specific standard for selecting the corresponding drainage mode according to the obtained stratum structure parameters is: When the stratum structure is the upper permeable stratum structure, and the soil type of the impermeable soil layer is rock-soil, the horizontal drainage blind pipe and the seepage blind ditch combined drainage mode is selected in the upper permeable soil layer; When the stratum structure is the upper permeable stratum structure, and the soil type of the impermeable soil layer is soft soil, the blind ditch and the seepage ditch combined drainage mode is selected in the upper permeable soil layer; When the stratum structure is the middle permeable stratum structure or the lower permeable stratum structure, and the thickness of the impermeable soil layer in the uppermost layer is less than 3m, the blind ditch drainage mode is selected in the middle permeable soil layer; When the stratum structure is the middle permeable stratum structure or the lower permeable stratum structure, and the thickness of the impermeable soil layer in the uppermost layer is not less than 3m, the blind ditch drainage mode is selected in the upper impermeable soil layer; When the stratum structure is the impermeable stratum structure, the open ditch drainage mode is selected in the upper impermeable soil layer.

2. The method according to claim 1, wherein, In step S1, the specific method for obtaining the stratum structure type of the road embankment comprises: S101, obtaining the thickness of different soil bodies in the road embankment, the position relationship of the soil bodies in the stratum and the permeability coefficient of the soil bodies; S102, constructing the road embankment structure according to the thickness and the position relationship of different soil bodies in the road embankment; According to the permeability coefficient of the soil bodies, the soil bodies are classified according to the permeability; S103, converting the soil bodies in the road embankment structure into soil layers according to the permeability of the adjacent soil bodies in the road embankment structure, and classifying the soil layers; S104, classifying the road embankment structure according to the distribution of different types of soil layers.

3. The method of claim 1, wherein the water removal mode is selected from the group consisting of: The water-permeable soil layer is composed of at least one water-permeable soil body; and the water-impermeable soil layer is composed of at least one water-impermeable soil body. ​ 4. The method according to claim 3, wherein The vertical and / or horizontal permeability coefficients of the water-permeable soil body satisfy: and / or The vertical and horizontal permeability coefficients of the water-impermeable soil body satisfy: and Wherein, 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 coefficient.

5. The method according to claim 4, wherein The design storm intensity: The design storm intensity: Wherein, q is the design storm intensity; P is the design storm recurrence period; t is the rainfall duration; A1 is the rain force parameter; C is the rain force variation parameter; b is the rainfall duration correction parameter; and n is the storm attenuation index.

6. The method of claim 1, wherein the water removal method is selected from the group consisting of: In step S2, the soil type is soft soil or rock soil. ​ 7. The method of claim 1, wherein the water removal method is selected from the group consisting of: In the upper water-permeable stratum structure, the water-permeable blind ditch is a drainage structure in which a water-permeable blind pipe is laid at the bottom of the blind ditch and coarse-grained materials are filled in the blind ditch for water interception and drainage. ​ 8. The method of claim 1, wherein the water removal method is selected from the group consisting of: In the upper water-permeable stratum structure, the water-permeable ditch is divided into a complete water-permeable ditch and an incomplete water-permeable ditch. ​ 9. The method according to claim 8, wherein the water is removed by filtration. The complete water-permeable ditch refers to a water-permeable ditch with a depth excavated to the water-impermeable soil layer; and the incomplete water-permeable ditch refers to a water-permeable ditch with a depth excavated in the water-permeable soil layer.

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