Method for determining cement mixing amount of key layer of semi-rigid asphalt pavement structure and product

Abstract

The invention relates to the field of road engineering, in particular to a method for determining the cement mixing amount of a key layer of a semi-rigid asphalt pavement structure and a related product, and the method comprises the following steps: selecting a proper pavement structure combination according to road roadbed conditions, environmental factors and traffic load conditions; preliminarily determining a design parameter range of a pavement structure combination according to a road pavement structure design specification and project experience; drawing up a plurality of groups of size parameters and material parameters in a design parameter range, and determining design parameters which have the greatest influence on the bottom tensile stress of the base layer and the bottom tensile stress of the subbase layer; the optimal value of the design parameter with the maximum influence is determined, and the cement mixing amount of the key layer is determined through the compressive resilience modulus-cement mixing amount relational graph; according to the method, the parameter combination of the pavement structure is optimized by combining stress analysis and an orthogonal test, the cement mixing amount of each key layer in the pavement structure is accurately determined, the bearing capacity and stability of the pavement are improved, and the risks of cracks and deformation are reduced.

Description

Technical Field

[0001] The invention relates to the field of road engineering, and in particular to a method and product for determining cement content of a key layer of a semi-rigid asphalt pavement structure. Background Art

[0002] In road engineering, cement stabilized base materials are widely used in the base and subbase of pavement, especially in semi-rigid pavement structures. The material properties of the base have a significant impact on the overall mechanical properties of the pavement. In order to ensure the long-term service life of the road, the material parameters and structural thickness of each layer must be accurately determined during the design phase. Among them, the cement content is a key factor affecting the strength, durability and construction cost of the base material, and it usually needs to be determined through experiments and theoretical analysis.

[0003] Existing methods for determining cement dosage usually rely on empirical formulas or conventional experiments, and lack accurate analysis for different road conditions (such as traffic load, climate environment, roadbed conditions, etc.). This method may lead to material waste or insufficient bearing capacity in practical applications. Especially under conditions of heavy traffic or poor roadbed, improper cement dosage can easily lead to quality problems such as early cracking and deformation of the road surface, reducing the service life of the road.

[0004] In addition, when determining the cement content, traditional methods often ignore the interaction between the various layers in the pavement structure, especially the stress transfer relationship between the base and subbase. The thickness and modulus of the base and subbase have an important influence on the overall bearing capacity, tensile stress and vertical deformation of the pavement. Therefore, optimizing the design parameters of each layer, especially the reasonable distribution of cement content, is of great significance to improving the mechanical properties of the pavement structure. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the method for determining the cement content in the prior art is not accurate enough, resulting in insufficient bearing capacity of the pavement structure or waste of materials. The purpose is to provide a method for determining the cement content of the key layer of a semi-rigid asphalt pavement structure and related products, which can accurately determine the cement content based on stress analysis, so as to optimize the mechanical properties of the pavement structure and reduce the risk of early pavement damage.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for determining cement content of a key layer of a semi-rigid asphalt pavement structure, comprising:

[0008] Select appropriate pavement structure combination according to road subgrade conditions, environmental factors and traffic load conditions;

[0009] Preliminarily determine the design parameter range of the pavement structure combination based on the road pavement structure design specifications and project experience;

[0010] Formulate multiple sets of dimensional parameters and material parameters within the design parameter range, and determine the design parameters that have the greatest impact on the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the sub-base layer;

[0011] Determine the optimal value of the design parameter with the greatest impact, and determine the cement content of the key layer through the compressive rebound modulus-cement content relationship diagram.

[0012] Specifically, the design parameters are divided into a size parameter range and a material parameter range; the size parameters include base layer thickness and subbase layer thickness, and the material parameters include upper base layer material modulus, base layer material modulus and soil base modulus.

[0013] Specifically, methods for determining the most influential design parameters include:

[0014] Formulate multiple groups of dimensional parameters and material parameters within the design parameter range and form multiple test groups;

[0015] The calculation and analysis of each test grouping results in the deflection, the tensile stress at the bottom of the base layer, and the tensile stress at the bottom of the subbase layer;

[0016] The range values ​​of various design parameters on deflection, tensile stress at the bottom of the base layer and tensile stress at the bottom of the sub-base layer are calculated, and the design parameters with the greatest influence on the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the sub-base layer are determined through range analysis.

[0017] Specifically, the method for determining the optimal value of the design parameter with the greatest impact includes:

[0018] The groups with lower than the designed deflection value, the designed base layer bottom tensile stress and the designed subbase layer bottom tensile stress in the primary test group are selected as the intermediate test group;

[0019] Determine the soil base modulus according to the geological survey report and select the final test group from the intermediate test groups;

[0020] Obtain the test group with the smallest sum of base thickness and subbase thickness in the final test group, and obtain the size parameters and material parameters;

[0021] The control variable method is used to obtain multiple secondary test groups on the most influential design parameters;

[0022] The deflection, the tensile stress at the bottom of the base layer, and the tensile stress at the bottom of the subbase layer of each secondary test group were obtained by calculation and analysis;

[0023] The secondary test grouping corresponding to when the tensile stress at the bottom of the base layer is equal to the tensile stress at the bottom of the subbase layer is obtained, and the design parameters in the secondary test grouping are determined to be the optimal values ​​of the design parameters with the greatest influence.

[0024] Specifically, the thickness of the base layer, the thickness of the subbase layer, the modulus of the upper base material, the modulus of the base material and the modulus of the soil foundation are analyzed and calculated by the road calculation software HPDS to obtain the deflection, the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the subbase layer;

[0025] The design deflection value, the design base layer bottom tensile stress value and the design subbase layer bottom tensile stress value are calculated by the road calculation software HPDS.

[0026] Optionally, n groups of design parameters are formulated within the design parameter range, including n upper base material moduli, n base material moduli, n soil base moduli, n base thicknesses, and n subbase thicknesses;

[0027] The n base material moduli, n soil base moduli, n base thicknesses, and n subbase thicknesses are bound into n data groups, and the n data groups are orthogonally tested with the n upper base material moduli to obtain n×n groups of primary test groupings.

[0028] Optionally, the method for obtaining the secondary test grouping includes:

[0029] Determine the specific values ​​of m design parameters with the greatest influence within the design parameter range;

[0030] Keeping the values ​​of other design parameters unchanged, combine the design parameters with the greatest influence to obtain m secondary test groups.

[0031] Optionally, the method for obtaining the compressive rebound modulus-cement dosage relationship diagram includes:

[0032] Prepare samples with different cement content and carry out standard curing procedures on the samples;

[0033] The compressive rebound modulus under different cement content conditions was obtained through the compressive rebound modulus test;

[0034] The model was fitted and the relationship diagram between compressive rebound modulus and cement content was obtained.

[0035] A terminal for determining the cement content of a key layer of a semi-rigid asphalt pavement structure comprises a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure as described above is implemented.

[0036] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure as described above.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] The method provided by the present invention first selects a suitable pavement structure combination, and preliminarily determines the range of design parameters, and analyzes the influence of various design parameters on the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the subbase layer through orthogonal experiments, determines the design parameter with the greatest influence, and finally calculates the optimal cement content through a compressive rebound modulus-cement content relationship diagram.

[0039] The present invention optimizes the parameter combination of the pavement structure by combining stress analysis with orthogonal experiments, and accurately determines the cement content of each key layer in the pavement structure, thereby improving the bearing capacity and stability of the pavement and reducing the risk of cracks and deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation of the embodiments of the present invention.

[0041] Figure 1 It is a schematic flow chart of a method for determining cement content of a key layer of a semi-rigid asphalt pavement structure according to the present invention.

[0042] Figure 2 This is a relationship diagram between compressive rebound modulus and cement content according to the present invention. DETAILED DESCRIPTION

[0043] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific implementation methods described herein are only used to explain the relevant content, rather than to limit the present invention.

[0044] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0045] In the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0046] For semi-rigid asphalt semi-rigid asphalt pavement structure, the present invention uses cement-stabilized red soil gravel as the road subbase. In order to overcome the limitations of the existing technology, a method for determining the cement content based on stress analysis is proposed. Through orthogonal tests of multiple sets of design parameters, combined with the pavement mechanics model, the stress distribution and deformation of each layer are calculated to ensure the optimal performance of the pavement structure under different conditions. This method can accurately determine the appropriate cement content according to specific road conditions and engineering requirements, reduce resource waste and increase the service life of the road.

[0047] Embodiment 1

[0048] like Figure 1 As shown, a method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure includes:

[0049] The first step is to select a suitable pavement structure combination based on road subgrade conditions, environmental factors and traffic load conditions.

[0050] The roadbed condition refers to the geological conditions of the lowest foundation (soil base) in road construction, including the bearing capacity, compaction, moisture, etc. Different roadbed conditions have different requirements for the design of the pavement structure. A weak roadbed requires a thicker structural layer to increase the bearing capacity.

[0051] Environmental factors include temperature, humidity, precipitation, etc. Environmental factors can affect the performance of the material. For example, temperature changes can cause thermal expansion or contraction of the material, while high humidity may cause the strength of the cement in the material to decrease.

[0052] Traffic load refers to the number, weight and frequency of vehicles traveling on the road. High traffic volumes and heavy loads put greater stress on the road surface, requiring a stronger pavement structure.

[0053] The second step is to preliminarily determine the design parameter range of the pavement structure combination based on road pavement structure design specifications and project experience.

[0054] Pavement structure design specifications refer to the standards for pavement design stipulated by the state or industry, including parameters such as pavement layer thickness and material strength. The specifications provide a basis for design and ensure that the pavement structure can meet basic safety and durability requirements.

[0055] Through the road pavement structure design specifications, combined with the experience and data accumulation from similar projects, the selection of optimized design parameters is assisted.

[0056] In the third step, multiple groups of dimensional parameters and material parameters are formulated within the design parameter range, and the design parameters with the greatest influence on the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the sub-base layer are determined.

[0057] The design parameters in this embodiment are divided into a size parameter range and a material parameter range; the size parameters include the base thickness and the subbase thickness, and the material parameters include the upper base material modulus, the base material modulus and the soil base modulus.

[0058] The tensile stress at the bottom of the base layer refers to the tensile stress at the junction of the pavement base and the soil base, while the tensile stress at the bottom of the subbase layer refers to the tensile stress between the subbase and the soil base. Excessive tensile stress may cause cracking or damage to the pavement.

[0059] The dimensions or material parameters that have the greatest impact on tensile stress can be determined through experiments or simulations.

[0060] The fourth step is to determine the optimal value of the design parameter with the greatest impact, and determine the cement content of the key layer through the compressive rebound modulus-cement content relationship diagram.

[0061] The compressive modulus of resilience refers to the ability of a material to recover to its original shape after being compressed, and is usually used to evaluate the strength performance of cement concrete or other pavement materials. A higher compressive modulus of resilience means that the material has a stronger ability to resist compression and deformation.

[0062] Cement content refers to the proportion of cement added to each unit of material. The determination of cement content is crucial to the strength and durability of the pavement. Too high a cement content will increase the cost, while too low a cement content may affect the bearing capacity of the pavement.

[0063] This method determines the key design parameters of each layer in the pavement structure by combining stress analysis and experimental data. Through simulation and experiments on different parameter combinations, the optimal design scheme that can effectively control the tensile stress of the base and subbase is found. Finally, through the relationship diagram between the compressive rebound modulus and the cement content, it is ensured that the pavement structure has sufficient bearing capacity and can reasonably control the construction cost.

[0064] Embodiment 2

[0065] This embodiment provides a method for determining the design parameter with the greatest impact, the method comprising:

[0066] Multiple groups of dimensional parameters and material parameters are formulated within the design parameter range to form multiple test groups; the dimensional parameters include base thickness and subbase thickness, and the material parameters include upper base material modulus, base material modulus and soil base modulus.

[0067] The deflection, the tensile stress at the bottom of the base layer, and the tensile stress at the bottom of the subbase layer of each test group are calculated and analyzed; specifically, the deflection, the tensile stress at the bottom of the base layer, and the tensile stress at the bottom of the subbase layer are analyzed and calculated by the road calculation software HPDS (existing software) on the base thickness, the subbase thickness, the modulus of the upper base material, the modulus of the base material, and the soil base modulus to obtain the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the subbase layer;

[0068] Calculate the range (difference between maximum and minimum) of each design parameter on deflection, tensile stress at the bottom of the base layer, and tensile stress at the bottom of the subbase layer. The range reflects the influence of a certain parameter on the performance index (such as deflection or tensile stress) in different test groups. The larger the range, the more significant the influence of the design parameter on the performance index.

[0069] The design parameters with the greatest impact on the tensile stress at the bottom of the base layer and the bottom of the sub-base layer are determined by range analysis. Range analysis is a method commonly used in multi-factor experimental analysis to determine which factors have the greatest impact on the results. In this method, by comparing the size of the range values ​​in different test groups, the design parameters with the greatest impact on the tensile stress at the bottom of the base layer and the bottom of the sub-base layer are found.

[0070] Embodiment 3

[0071] Methods for determining the optimal values ​​of the most influential design parameters include:

[0072] The groups with lower values ​​than the design deflection value, the design tensile stress at the bottom of the base layer and the design tensile stress at the bottom of the subbase layer in the first test grouping are selected as intermediate test groups; the design deflection value, the design tensile stress at the bottom of the base layer and the design tensile stress at the bottom of the subbase layer are calculated by the road calculation software HPDS.

[0073] Design deflection refers to the maximum vertical deformation of the road surface under traffic load. This value is set based on the allowable deformation range required by the design, and test groups exceeding this value will be eliminated.

[0074] The soil foundation modulus is determined according to the geological survey report, and the final test group is screened from the intermediate test groups; the geological survey report provides the soil foundation modulus, which reflects the bearing capacity and deformation performance of the soil.

[0075] The test group with the smallest sum of base thickness and subbase thickness in the final test group is obtained, and the size parameters and material parameters are obtained; the minimum sum of base thickness and subbase thickness can optimize the thickness of the pavement structure and reduce material and construction costs while ensuring that the pavement strength and stability are met. The minimum thickness means the least material use and the most economical construction.

[0076] The control variable method is used to obtain multiple secondary test groups for the design parameters with the greatest impact; the control variable method is an experimental method that keeps other conditions except one variable unchanged during the experiment to analyze the impact of the variable on the results. That is: determine the specific values ​​of m design parameters with the greatest impact within the design parameter range; keep the values ​​of the remaining design parameters unchanged, combine the design parameters with the greatest impact, and obtain m secondary test groups.

[0077] The deflection, the tensile stress at the bottom of the base layer, and the tensile stress at the bottom of the subbase layer of each secondary test group were obtained by calculation and analysis;

[0078] Obtain the secondary test grouping corresponding to the case where the tensile stress at the bottom of the base layer is equal to the tensile stress at the bottom of the sub-base layer, and determine the design parameters in the secondary test grouping as the optimal values ​​of the design parameters with the greatest impact. The condition that the tensile stress at the bottom of the base layer is equal to the tensile stress at the bottom of the sub-base layer is used to ensure the stress balance of the pavement structure and prevent structural failure caused by stress concentration.

[0079] Embodiment 4

[0080] The method for obtaining the compressive rebound modulus-cement dosage relationship diagram includes:

[0081] Samples with different cement content were prepared and subjected to standard curing procedures.

[0082] Cement content refers to the proportion of cement added to each unit of material. Different cement content directly affects the strength and compressive properties of the material. In experiments, multiple groups of different cement content are usually selected for comparison, such as 2%, 4%, 6%, 8%, etc., to cover a wider range of cement content. According to the experimental standards, multiple specimens are prepared using the corresponding cement content, and all specimens are allowed to reach their maximum strength under specified environmental conditions (such as temperature and humidity).

[0083] The compressive rebound modulus under different cement content conditions is obtained through the compressive rebound modulus test; the specimens are subjected to a compression test using specific equipment, and the rebound modulus of each specimen under pressure is recorded.

[0084] Fit it and obtain the compressive rebound modulus-cement content relationship diagram. Find the best fitting straight line for a set of data points through linear fitting. In this method, the mathematical relationship between cement content and compressive rebound modulus can be established by linear fitting the compressive rebound modulus data at different cement content. If the data shows an obvious linear trend, it can be described by a linear equation; if the relationship is nonlinear, a more complex fitting method may be required. The compressive rebound modulus-cement content relationship diagram shows the relationship between cement content and compressive rebound modulus. Generally, as the cement content increases, the compressive rebound modulus will also increase, but the increase may gradually decrease. Through this relationship diagram, the optimal cement content can be intuitively determined.

[0085] Embodiment 5

[0086] This embodiment provides a specific example.

[0087] The connecting line of a certain project is taken as the research object. The connecting line mainly connects the urban area and the airport. It is built according to the standards of municipal branch roads. The motor vehicle road surface width is 7.5 meters, with two lanes in both directions. Combined with the project's traffic volume forecast data and traffic composition analysis, the cumulative axle load is calculated to be about 1.2 million.

[0088] According to the preliminary data, the road subgrade rebound modulus is preliminarily determined to be 35-50Mpa. According to the on-site investigation, the material source is mainly gravel, and the inorganic binder is gravel. The pavement structure combination is preliminarily determined to be 5cm asphalt penetration crushed stone + 15-20cm cement stabilized gravel + 15-25cm cement stabilized gravel.

[0089] Four groups of data are proposed for orthogonal test analysis. The method of orthogonal test is as follows: n groups of design parameters are proposed within the design parameter range, including n upper base material moduli, n base material moduli, n soil base moduli, n base thicknesses, and n subbase thicknesses;

[0090] The n base material moduli, n soil base moduli, n base thicknesses, and n subbase thicknesses are bound into n data groups, and the n data groups are orthogonally tested with the n upper base material moduli to obtain n×n groups of primary test groupings.

[0091] The four sets of data are shown in the following table.

[0092] Orthogonal factor level table

[0093]

[0094] Conduct an orthogonal test and obtain an orthogonal experimental table.

[0095]

[0096] The above data are combined and analyzed using the road calculation software HPDS (existing software) to obtain the calculation results of road surface deflection, base layer bottom tensile stress and sub-base layer bottom tensile stress for acceptance.

[0097]

[0098] Using the calculation results, analyze the impact of each factor on the calculation results. The size of the influencing factor is represented by the range value, and the order of size is shown in the following table.

[0099]

[0100]

[0101] By using the road calculation software HPDS (existing software) to calculate the design deflection value and tensile stress, it can be seen that the maximum value of the design road surface deflection is 43.7 (0.01mm), the maximum values ​​of the tensile stress at the bottom of the base layer and the bottom of the subbase layer are 0.33 and 0.27MPa. By comparison, it can be seen that test groups 1, 2, 4, 5, 7, 8, 12, 13, 14, and 15 can meet the design requirements.

[0102] Later, according to the geological survey report, the on-site rebound modulus was taken as 40MPa, and test groups 2, 5, 12, and 15 could meet the requirements. Among them, the combined thickness of the base and subbase of experimental group 2 was the smallest, and the cost was the lowest.

[0103] The thickness of the upper and lower layers are 18 cm and 19 cm respectively, and the modulus of the upper and lower layers is 1350 MPa. According to the range analysis, it can be seen that the modulus of the base material has the greatest influence on the tensile stress of the upper and lower layers of the road.

[0104] The modulus of the upper base material, the soil base modulus, the base thickness, and the subbase thickness are controlled unchanged, and the base material modulus is adjusted to be within the standard value (600-1200). The initial value is 600, with an interval of 200, and 4 sets of data are evenly distributed at 600, 800, 1000, and 1200 MPa, which are confirmed to be 1200, 1400, 1600, and 1800 MPa at 15°C.

[0105] The controlled variable method is used to calculate the material modulus of cement-stabilized laterite gravel under the optimal reasonable structure.

[0106] Keeping other factors unchanged, adjust the modulus of the base material and determine multiple sets of data.

[0107]

[0108]

[0109] The calculation results of road surface deflection, base layer and subbase layer bottom tensile stress are obtained by using the road calculation software HPDS (existing software).

[0110]

[0111] According to the calculation theory of asphalt pavement structure (layered elastic system theory), the tensile stress at the bottom of the semi-rigid material layer should be less than the allowable tensile stress, which is used as a design indicator. When the tensile stress at the bottom of the upper base layer is equal to the tensile stress at the bottom of the base layer and meets the design requirements, the overall material is the least and the pavement structure combination is the best.

[0112] When the tensile stress at the bottom of the base layer is equal to the tensile stress at the bottom of the subbase layer, the pavement structure is in the optimal state. The relevant graph is drawn to obtain the compressive rebound modulus of the material corresponding to the intersection point.

[0113] According to the laboratory data, the compressive elastic modulus values ​​of different cement content were averaged to draw the relationship diagram between the compressive elastic modulus and cement content ( Figure 2 ), and the least square method was used to perform linear fitting. The cement content corresponding to the material compressive elastic modulus was obtained through the chart as the reference data for the construction test section.

[0114] Embodiment 6

[0115] A terminal for determining the cement content of a key layer of a semi-rigid asphalt pavement structure comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure as described above is implemented.

[0116] The memory can be used to store software programs and modules. The processor executes various functional applications and data processing of the terminal by running the software programs and modules stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an execution program required for at least one function, etc.

[0117] The data storage area can store data created according to the use of the terminal, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0118] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the above-mentioned method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure.

[0119] A computer program product includes a computer program or set of instructions for performing specific tasks or implementing specific functions. These programs or instructions are designed to be executed by a processor to implement a series of predefined steps or operations. The program product may be stored in various forms of computer storage media, such as memory, hard disk, solid-state drive, optical disk or other forms of digital storage devices. It may exist in the form of compiled binary code or in the form of scripts or bytecodes that can be executed by an interpreter. The program product uses carefully designed algorithms and logical instructions to enable the processor to process data in a specific order and manner to complete various functions such as data analysis, user interaction, device control, etc.

[0120] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0121] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0122] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above invention, and these changes or modifications are still within the scope of the present invention.

Claims

1. A method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure, characterized in that: include: Select appropriate pavement structure combination according to road subgrade conditions, environmental factors and traffic load conditions; Preliminarily determine the design parameter range of the pavement structure combination based on the road pavement structure design specifications and project experience; Formulate multiple sets of dimensional parameters and material parameters within the design parameter range, and determine the design parameters that have the greatest impact on the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the sub-base layer; Determine the optimal value of the design parameter with the greatest impact, and determine the cement content of the key layer through the compressive rebound modulus-cement content relationship diagram.

2. The method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure according to claim 1, characterized in that: The design parameters are divided into a size parameter range and a material parameter range; the size parameters include base thickness and subbase thickness, and the material parameters include upper base material modulus, base material modulus and soil base modulus.

3. The method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure according to claim 2, characterized in that: Methods for determining the most influential design parameters include: Determine the design deflection value, design base layer bottom tensile stress and design subbase layer bottom tensile stress for this type of pavement structure; Calculate the deflection value, tensile stress at the bottom of the base layer, and tensile stress at the bottom of the subbase layer for the acceptance inspection of this type of pavement structure; Formulate multiple groups of dimensional parameters and material parameters within the design parameter range and form multiple test groups; The calculation and analysis of each test grouping results in the deflection, the tensile stress at the bottom of the base layer, and the tensile stress at the bottom of the subbase layer; The range values ​​of various design parameters on deflection, tensile stress at the bottom of the base layer and tensile stress at the bottom of the sub-base layer are calculated, and the design parameters with the greatest influence on the tensile stress at the bottom of the base layer and the tensile stress at the bottom of the sub-base layer are determined through range analysis.

4. The method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure according to claim 3, characterized in that: Methods for determining the optimal values ​​of the most influential design parameters include: The groups with lower than the designed deflection value, the designed base layer bottom tensile stress and the designed subbase layer bottom tensile stress in the primary test group are selected as the intermediate test group; Determine the soil base modulus according to the geological survey report and select the final test group from the intermediate test groups; Obtain the test group with the smallest sum of base thickness and subbase thickness in the final test group, and obtain the size parameters and material parameters; The control variable method is used to obtain multiple secondary test groups on the most influential design parameters; The deflection, the tensile stress at the bottom of the base layer, and the tensile stress at the bottom of the subbase layer of each secondary test group were obtained by calculation and analysis; The secondary test grouping corresponding to when the tensile stress at the bottom of the base layer is equal to the tensile stress at the bottom of the subbase layer is obtained, and the design parameters in the secondary test grouping are determined to be the optimal values ​​of the design parameters with the greatest influence.

5. The method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure according to claim 3, characterized in that: The road calculation software HPDS is used to analyze and calculate the base thickness, subbase thickness, upper base material modulus, base material modulus and soil base modulus to obtain deflection, base layer bottom tensile stress, subbase layer bottom tensile stress; The design deflection value, the design base layer bottom tensile stress value and the design subbase layer bottom tensile stress value are calculated by the road calculation software HPDS.

6. The method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure according to claim 3, characterized in that: Formulate n groups of design parameters within the design parameter range, including n upper base material moduli, n base material moduli, n soil base moduli, n base thicknesses, and n subbase thicknesses; The n base material moduli, n soil base moduli, n base thicknesses, and n subbase thicknesses are bound into n data groups, and the n data groups are orthogonally tested with the n upper base material moduli to obtain n×n groups of primary test groupings.

7. The method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure according to claim 5, characterized in that: The methods for obtaining the secondary test grouping include: Determine the specific values ​​of m design parameters with the greatest influence within the design parameter range; Keeping the values ​​of other design parameters unchanged, combine the design parameters with the greatest influence to obtain m secondary test groups.

8. The method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure according to claim 5, characterized in that: The method for obtaining the compressive rebound modulus-cement dosage relationship diagram includes: Prepare samples with different cement content and carry out standard curing procedures on the samples; The compressive rebound modulus under different cement content conditions was obtained through the compressive rebound modulus test; The model was fitted and the relationship diagram between compressive rebound modulus and cement content was obtained.

9. A terminal for determining cement content of a key layer of a semi-rigid asphalt pavement structure, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements a method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure as described in any one of claims 1-8.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, a method for determining the cement content of a key layer of a semi-rigid asphalt pavement structure as described in any one of claims 1-8 is implemented.

Images