Drainage mode screening method based on highway subgrade stratum structure

Abstract

The invention relates to the technical field of engineering design, in particular to a drainage mode screening method based on a highway subgrade stratum structure. The method comprises the following steps: S1, acquiring a stratigraphic structure type of a highway subgrade; s2, acquiring different stratum structure parameters according to the stratum structure type; s3, selecting a corresponding drainage mode according to the obtained stratum structure parameters; according to the method, the drainage modes of the highway subgrade are screened and matched according to the stratum structure characteristics of different types of highway subgrades and the drainage principle, the structural characteristics and the drainage effect of the drainage structure, so that the drainage modes are more suitable for the stratum structure, the drainage effect is guaranteed, and meanwhile the drainage efficiency is improved. The engineering amount and the construction cost during construction of the drainage structure are remarkably reduced, the engineering time is shortened, the damage degree of the drainage structure to the stratum is also reduced, and protection of the road environment ecological environment is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of road design methods, in particular to the screening of road drainage methods, and in particular to a drainage method screening method based on the stratigraphic structure of a highway subgrade. Background Art

[0002] Water is one of the main causes of damage to roads and structures along them. Therefore, in order to reduce or even avoid the damage caused by water to road facilities, the problem of road drainage must be considered during the design and construction of roads. Road drainage facilities are road auxiliary structures designed for road drainage, and are also the most direct and effective means to improve and solve the damage caused by water to roads.

[0003] Road drainage structures are divided into road base surface drainage facilities and road base underground drainage facilities. Road base surface drainage facilities include structures such as side ditches, intercepting ditches, drainage ditches, waterfalls and rapids, aqueducts, inverted siphons and water pools; road base underground drainage facilities include structures such as culverts, infiltration ditches, infiltration wells, etc. A road drainage structure designed specifically according to the regional characteristics and topographic features of the road will have higher drainage efficiency and lower construction costs, which is also commonly considered in the design and construction of road drainage structures today. However, in the process of selecting road drainage methods, the stratum structure is also an important factor affecting the road drainage method, and in the prior art, there is no relevant record of a method for selecting a drainage method based on the stratum structure of a highway road base. Summary of the invention

[0004] The purpose of the present invention is to provide a drainage mode screening method based on the roadbed stratigraphic structure.

[0005] The present invention provides a method for screening drainage modes based on the roadbed stratigraphic structure, comprising the following steps:

[0006] S1. Obtaining the type of stratum structure of the highway subgrade;

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

[0008] S3. Select a corresponding drainage method according to the obtained stratum structure parameters.

[0009] The present invention discloses a drainage mode screening method based on the stratigraphic structure of a highway subgrade. The drainage modes of the highway subgrade are screened and matched according to the stratigraphic structural characteristics of different types of highway subgrades, as well as the drainage principle, structural characteristics and drainage effect of the drainage structure, so that the drainage mode is more suitable for the stratigraphic structure, and the drainage effect is ensured. At the same time, the engineering amount and construction cost of the drainage structure construction are significantly reduced, the engineering time is shortened, and the degree of damage to the stratigraphic structure by the drainage structure is reduced, which is beneficial to the protection of the ecological environment of the road environment.

[0010] Wherein, in step S1, preferably, the specific method for obtaining the stratum structure type of the roadbed includes:

[0011] S101, obtaining the thickness of different soil bodies in the highway subgrade layer, the position relationship of the soil bodies in the stratum, and the permeability coefficient of the soil bodies;

[0012] S102, constructing a roadbed layer structure according to the thickness of different soil bodies in the roadbed layer and the position relationship in the stratum;

[0013] According to the permeability coefficient of the soil, the soil is classified according to its permeability; the soil is divided into permeable soil and impermeable soil;

[0014] S103, according to the permeability of adjacent soil bodies in the roadbed layer structure, converting the soil bodies in the roadbed layer structure into soil layers, and classifying the soil layers; the soil layers are divided into permeable soil layers and impermeable soil layers;

[0015] S104. Classify the roadbed stratum structure according to the distribution of different types of soil layers in the roadbed stratum structure; the roadbed stratum structure is divided into a permeable stratum structure and an impermeable stratum structure.

[0016] Preferably, the types of stratum structures include impermeable stratum structures, upper permeable stratum structures, middle permeable stratum structures and lower permeable stratum structures.

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

[0018] Or the upper surface of the permeable soil layer with a thickness of not less than 3m is more than 10m from the ground;

[0019] or contains only an impermeable soil layer; in the upper permeable stratum structure, the permeable soil layer is located at the uppermost layer of the stratum structure and has a thickness of not less than 3m;

[0020] In the middle 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. At the same time, the permeable soil layer is close 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 uppermost layer of the stratum structure, and has a thickness greater than 3m but not greater than 10m, and the permeable soil layer is close to the uppermost impermeable soil layer, and has a thickness not less than 3m.

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

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

[0024] and / or

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

[0026] and

[0027] Where a is the vertical permeability coefficient; b is the horizontal permeability coefficient; q is the design rainstorm intensity (L / s·hm 2 ), y is the runoff coefficient, which is 0.3, and F is the catchment area (hm 2 ); K is the correction coefficient, which is 0.05.

[0028] If the permeability coefficient is too small, the water infiltration rate of the soil will be slow, resulting in insufficient estimation of the drainage effect of the designed drainage structure. The accumulated water in the highway roadbed cannot be discharged in time, causing damage to the roadbed. If the permeability coefficient is too large, the drainage effect of the soil will be underestimated, resulting in the need to design a more complex and efficient drainage structure, resulting in a waste of resources and construction costs.

[0029] The classification standard of permeable soil and impermeable soil is determined according to the structure of highway subgrade and the soil characteristics of the area. The permeability of soil directly affects the overall efficiency of the drainage system. Soil with good permeability can infiltrate and discharge water more effectively, reduce surface runoff and soil loss, while in soil with poor permeability, water is not easy to discharge, which may cause water accumulation, increase soil moisture and affect the stability of highway subgrade. The preferred classification standard can better achieve the drainage effect of highway subgrade structure and significantly reduce the damage of water to highway subgrade.

[0030] Preferably, the designed rainstorm intensity

[0031] The design rainstorm intensity:

[0032] Among them: q is the design rainstorm intensity; P is the design rainstorm return 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; n is the rainstorm attenuation index.

[0033] Among them, in step S2, preferably, the stratum 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 permeable stratum structure or the lower permeable stratum structure; 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 sediments with high natural water content, high compressibility, low bearing capacity and a small amount of humus, usually gray in appearance, with high natural porosity and high natural water content; the soft soil includes at least one of silty clay, humus, 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] Among them, in step S3, preferably, the specific criteria for selecting the corresponding drainage method according to the acquired stratum structure parameters are:

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

[0038] When the stratum structure is an upper permeable stratum structure 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 upper permeable soil layer;

[0039] When the stratum structure is a middle permeable stratum structure or a lower permeable stratum structure, and the thickness of the topmost impermeable soil layer is less than 3m, choose to set up a blind ditch drainage method in the middle permeable soil layer;

[0040] When the stratum structure is a middle permeable stratum structure or a lower permeable stratum structure, and the thickness of the uppermost impermeable soil layer is not less than 3m, choose to set up a blind ditch drainage method in the upper impermeable soil layer;

[0041] When the stratum structure is impermeable, choose to set up open ditch drainage in the topmost impermeable soil layer.

[0042] Preferably, in the upper permeable stratum structure, the seepage blind ditch is a drainage structure in which a permeable blind pipe is laid at the bottom of the blind ditch and coarse aggregate is filled in the blind ditch to intercept and drain water.

[0043] Preferably, in the upper permeable stratum structure, the infiltration ditch is divided into a complete infiltration ditch and an incomplete infiltration ditch; the complete infiltration ditch refers to an infiltration ditch excavated to the impermeable soil layer; the incomplete infiltration ditch refers to an infiltration ditch excavated to a depth within the permeable soil layer.

[0044] Preferably, in an impermeable stratum structure, the size of the open ditch is related to the soil type and thickness of the uppermost impermeable soil layer.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

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

[0047] 2. The drainage mode screening method based on the highway roadbed stratigraphic structure of the present invention ensures the drainage effect while significantly reducing the engineering workload and construction cost during the construction of the drainage structure, shortening the engineering time, and reducing the degree of damage to the stratum by the drainage structure, which is beneficial to the protection of the road environment ecological environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flow chart of a drainage method screening method based on a highway subgrade stratigraphic structure in Example 1 of the present invention. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0050] Example 1

[0051] The method of the present invention is used to screen the road drainage method according to the roadbed layer structure of a certain highway. The specific steps (process as shown in the following figure) are as follows: Figure 1 As shown) as follows:

[0052] S1. Obtain the stratigraphic structure type of a highway roadbed, as shown in Table 1;

[0053] Table 1 Classification of the layer structure of a highway base

[0054]

[0055]

[0056] S2. According to the type of stratum structure, different stratum structure parameters are obtained; the stratum structure parameters include: the soil type of the impermeable layer in the upper permeable stratum structure; the thickness of the impermeable layer in the upper layer of the middle permeable stratum structure or the lower permeable stratum structure; the soil type and thickness of the impermeable layer in the upper layer of the impermeable stratum structure;

[0057] S3. The specific criteria for selecting the corresponding drainage method according to the obtained stratum structure parameters are:

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

[0059] When the stratum structure is an upper permeable stratum structure 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 upper permeable soil layer;

[0060] When the stratum structure is a middle permeable stratum structure or a lower permeable stratum structure, and the thickness of the topmost impermeable soil layer is less than 3m, choose to set up a blind ditch drainage method in the middle permeable soil layer;

[0061] When the stratum structure is a middle permeable stratum structure or a lower permeable stratum structure, and the thickness of the uppermost impermeable soil layer is not less than 3m, choose to set up a blind ditch drainage method in the upper impermeable soil layer;

[0062] When the ground structure is impermeable, choose to set up open ditch drainage in the uppermost impermeable soil layer;

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

[0064] Table 2 Screening results of drainage methods for a highway

[0065]

[0066]

[0067] By screening and matching the stratigraphic structure and drainage methods of different types of highway subgrades, the drainage method is made more suitable for the stratigraphic structure, ensuring the drainage effect while significantly reducing the engineering workload and construction cost during drainage structure construction, shortening the project time, and reducing the degree of damage to the stratigraphic structure by the drainage structure, which is beneficial to the protection of the road environment 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 in the protection scope of the present invention.

Claims

1. A drainage method screening method based on the roadbed stratigraphic structure, characterized in that: The following steps are involved: S1. Obtaining the type of stratum structure of the highway subgrade; the stratum structure type includes an impermeable stratum structure, an upper permeable stratum structure, a middle permeable stratum structure and a lower permeable stratum structure; S2. Obtain different stratum structure parameters according to the stratum structure type; The formation structure parameters include: Soil type of impermeable soil layer in the upper permeable stratum structure; The thickness of the uppermost impermeable soil layer in the middle permeable stratum structure or the lower permeable stratum structure; Soil type and thickness of the uppermost impermeable soil layer in the impermeable stratum structure; S3. Selecting a corresponding drainage method according to the obtained stratum structure parameters; the specific criteria for selecting a corresponding drainage method according to the obtained stratum structure parameters are: When the stratum structure is an upper permeable stratum structure and the soil type of the impermeable soil layer is rock soil, a drainage method combining a horizontal drainage blind pipe and a seepage blind ditch is selected in the upper permeable soil layer; When the stratum structure is an upper permeable stratum structure 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 upper permeable soil layer; When the stratum structure is a middle permeable stratum structure or a lower permeable stratum structure, and the thickness of the topmost impermeable soil layer is less than 3m, choose to set up a blind ditch drainage method in the middle permeable soil layer; When the stratum structure is a middle permeable stratum structure or a lower permeable stratum structure, and the thickness of the uppermost impermeable soil layer is not less than 3m, choose to set up a blind ditch drainage method in the upper impermeable soil layer; When the stratum structure is impermeable, choose to set up open ditch drainage in the topmost impermeable soil layer.

2. The drainage mode screening method according to claim 1 or 2, characterized in that: In step S1, the specific method for obtaining the stratum structure type of the roadbed includes: S101, obtaining the thickness of different soil bodies in the highway subgrade layer, the position relationship of the soil bodies in the stratum, and the permeability coefficient of the soil bodies; S102, constructing a roadbed layer structure according to the thickness of different soil bodies in the roadbed layer and the position relationship in the stratum; Based on the permeability coefficient of the soil, the soil is classified according to its permeability; S103, converting the soil in the roadbed layer structure into soil layers according to the water permeability of adjacent soil in the roadbed layer structure, and classifying the soil layers; S104. Classify the roadbed stratigraphic structure according to the distribution of different types of soil layers in the roadbed stratigraphic structure.

3. The drainage method screening method according to claim 1, characterized in that: In step S1, in the impermeable stratum structure, the thickness of the permeable soil layer is less than 3m; Or the upper surface of the permeable soil layer with a thickness of not less than 3m is more than 10m from the ground; or contains only an impermeable soil layer; in the upper permeable stratum structure, the permeable soil layer is located at the uppermost layer of the stratum structure and has a thickness of not less than 3m; In the middle 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. At the same time, the permeable soil layer is close 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 uppermost layer of the stratum structure, and has a thickness greater than 3m but not greater than 10m, and the permeable soil layer is close to the uppermost impermeable soil layer, and has a thickness not less than 3m.

4. The drainage mode screening method according to claim 3, characterized in that: The permeable soil layer is composed of at least one layer of permeable soil; the impermeable soil layer is composed of at least one layer of impermeable soil.

5. The drainage mode screening method according to claim 4, characterized in that: The vertical permeability coefficient and / or horizontal permeability coefficient of the permeable soil mass satisfies: and / or The vertical permeability coefficient and horizontal permeability coefficient of the impermeable soil satisfy: and Among them, a is the vertical permeability coefficient; b is the horizontal permeability coefficient; q is the design rainstorm intensity; y is the runoff coefficient; F is the catchment area; and K is the correction factor.

6. The drainage mode screening method according to claim 5, characterized in that: The design rainstorm intensity: The design rainstorm intensity: Among them: q is the design rainstorm intensity; P is the design rainstorm return 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; n is the rainstorm attenuation index.

7. The drainage mode screening method according to claim 1, characterized in that: In step S2, the soil type is soft soil or rock soil.

8. The drainage mode screening method according to claim 1, characterized in that: In the upper permeable stratum structure, the seepage blind ditch is a drainage structure in which a permeable blind pipe is laid at the bottom of the blind ditch and coarse aggregate is filled in the blind ditch to intercept and drain water.

9. The drainage mode screening method according to claim 1, characterized in that: In the upper permeable stratum structure, the infiltration ditch is divided into a complete infiltration ditch and an incomplete infiltration ditch.

10. The drainage mode screening method according to claim 9, characterized in that: The complete infiltration ditch refers to a ditch excavated to the depth of the impermeable soil layer; the incomplete infiltration ditch refers to a ditch excavated to the depth of the permeable soil layer.

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