CN109977611B

CN109977611B - Asphalt pavement forward design method oriented to service performance and application

Info

Publication number: CN109977611B
Application number: CN201910315003.7A
Authority: CN
Inventors: 毕玉峰; 丁婷婷; 孙建秀; 徐润; 王卓; 李夕林; 李琳
Original assignee: Shandong Provincial Communications Planning and Design Institute Group Co Ltd
Current assignee: Shandong Provincial Communications Planning and Design Institute Group Co Ltd
Priority date: 2019-04-18
Filing date: 2019-04-18
Publication date: 2023-06-23
Anticipated expiration: 2039-04-18
Also published as: CN109977611A

Abstract

The invention provides a forward design method and application of an asphalt pavement facing to service performance, which are used for calculating the accumulated action times of equivalent design axle load on a design lane in the design service life corresponding to each design index according to the investigation and analysis result of road traffic parameters and the design service life; according to the initial pavement structure of the typical structural layer of the road and the thickness of each structural layer, initially setting the dynamic modulus and Poisson's ratio of the pavement structural layer; calculating the mechanical response of the pavement structure and the design index of the asphalt pavement material according to the determined design time equivalent design axle load accumulated action times and the primary pavement structure, and determining the extremum of the material index; and determining pavement materials according to the determined extreme value, and selecting a pavement forward design scheme by combining the set pavement structure. The method increases the range of pavement materials which can be used for road construction on the premise that the number of times of axial load action in the design year is met and the pavement has no structural disease, and realizes the maximum utilization of the materials.

Description

Asphalt pavement forward design method oriented to service performance and application

Technical Field

The disclosure relates to the field of civil construction, in particular to a forward design method and application of an asphalt pavement facing usability.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

The road surface structural design and the mixed material design are combined in the road asphalt pavement design standard, the rationality of the material design parameters, the primary pavement structural layer combination and the structural layer thickness is determined through pavement structure checking, and the structure checking indexes comprise: the fatigue cracking life of the asphalt mixture layer, the fatigue cracking life of the inorganic binder stabilizing layer, the permanent deformation of the asphalt mixture layer, the pressure strain of the roadbed top surface, the low-temperature cracking index and the like. The road surface design method based on the parameters can ensure that the design result meets the road performance requirement, but according to the knowledge of the inventor, the design parameter can be accurately determined only by the fact that a designer needs to have more abundant engineering experience in the specific implementation process of the method, and the material, time and other resources are wasted although the checking result still meets the requirement for a plurality of sets of existing road surface structures for the designer with insufficient experience.

Disclosure of Invention

In order to solve the problems, the disclosure provides a forward design method and application of an asphalt pavement facing to service performance, and the disclosure increases the range of pavement materials available for road construction on the premise of meeting the design time and the number of times of internal loading without structural diseases of the pavement, thereby realizing the maximum utilization of the materials.

According to some embodiments, the present disclosure employs the following technical solutions:

a forward design method of an asphalt pavement facing service performance comprises the following steps:

calculating the equivalent design axle load accumulated action times on a design lane in the design service life corresponding to each design index according to the road traffic parameter investigation analysis result and the design service life;

according to the initial pavement structure of the typical structural layer of the road and the thickness of each structural layer, initially setting the dynamic modulus and Poisson's ratio of the pavement structural layer;

calculating the mechanical response of the pavement structure and the design index of the asphalt pavement material according to the determined design time equivalent design axle load accumulated action times and the primary pavement structure, and determining the extremum of the material index;

and determining pavement materials according to the determined extreme value, and determining a pavement forward design scheme by combining the set pavement structure.

As a further limitation, the cumulative number of times of axle load of equivalent design on a design lane within the design service life is calculated according to the method of calculating annex A of the highway asphalt pavement design Specification (JTGD 50-2017).

As a further limitation, the roadbed soil quality and the roadbed top equivalent rebound modulus of the road location and the local temperature and humidity conditions are determined, and the pavement structure combination and the initial construction of the thickness of each structure layer are carried out according to the conditions.

By way of further limitation, the as-synthesized modulus of elasticity is the minimum specified by the specification.

As a further limitation, according to the layering method of annex B of the highway asphalt pavement design specification (JTGD 50-2017), the asphalt mixture layer is divided into a plurality of layers, the thickness of each layer is preliminarily determined, the tensile stress of the bottom of the inorganic binder stabilizing layer and the vertical compressive stress of the top surface of each layer of the asphalt mixture layer are calculated by adopting an elastic layered continuous system theory under the action of double-circle uniform vertical load, and then the permanent deformation correction coefficient of each layer is obtained.

As a further limitation, the asphalt pavement material index is back calculated by using the asphalt pavement structural design equation, and the material design index extremum is given.

As a further limitation, if the material index value is greater than the requirement of the specification on the material performance, the modulus of each layer needs to be adjusted, and if the material index value is less than the requirement of the specification on the material performance, the minimum value of the material design index is taken as the extremum of the material index.

And judging whether to perform checking calculation of the anti-freezing thickness, if so, performing checking calculation of the anti-freezing thickness after determining materials of each layer of the pavement, and if not, selecting a pavement forward design scheme.

A computer readable storage medium having stored therein a plurality of instructions adapted to be loaded by a processor of a terminal device and to perform the method of forward-looking asphalt pavement design for performance of use.

A terminal device comprising a processor and a computer readable storage medium, the processor configured to implement instructions; the computer readable storage medium is for storing a plurality of instructions adapted to be loaded by a processor and to perform the performance-oriented asphalt pavement forward-direction design method.

Compared with the prior art, the beneficial effects of the present disclosure are:

the method and the device can increase the range of the pavement materials which can be used for road construction on the premise that the number of times of axial load action in the design period is met and the pavement has no structural disease by determining the extremum of the material index, so that the maximum utilization of the materials is realized.

The operation process is simple and easy, and can be realized by combining with the highway asphalt pavement design Specification (JTGD 50-2017), so that the method can be applied to designers with insufficient experience, and has higher practicability.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate and explain the exemplary embodiments of the disclosure and together with the description serve to explain the disclosure, and do not constitute an undue limitation on the disclosure.

FIG. 1 is a flow chart of an embodiment of a pavement design;

the specific embodiment is as follows:

the disclosure is further described below with reference to the drawings and examples.

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments in accordance with the present disclosure. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

step one: and calculating the accumulated action times of equivalent design axle load on the design lane within the service life of the design according to the calculation method of annex A of the highway asphalt pavement design specification (JTGD 50-2017). The number of cumulative action of the equivalent design axle load corresponding to the permanent deformation of the asphalt mixture layer is calculated to be 31,856,602, and the number of cumulative action of the equivalent design axle load corresponding to the fatigue cracking of the inorganic binder layer is calculated to be 1,498,499,410.

Step two: and (5) investigation is carried out to determine the roadbed soil quality and the equivalent rebound modulus of the top surface of the roadbed of the project site and the local temperature and humidity conditions. The roadbed soil of the project is silty clay, and the equivalent rebound modulus value of the top surface of the roadbed is 50MPa; the local standard equivalent temperature is 21.8 ℃, the low temperature design temperature is-1.7 ℃, and the roadbed humidity is a coefficient of 1.

Step three: the pavement structure is assembled and the thickness of each structure layer is equal to that of the pavement structure. The initial modulus of elasticity is the minimum value specified in the specification, the pavement structure combination and the thickness of each structural layer are the local typical pavement structure, and the specific parameters are shown in table 1.

Step four: and (3) calculating pavement structure response by utilizing the elastic lamellar continuous system theory according to the traffic volume in the design period determined in the step one and the pavement structure initially prepared in the step three, and back-calculating asphalt pavement material indexes by utilizing an asphalt pavement structure design equation to give material design index extremum. The tables and formulas cited below are from the highway asphalt pavement design Specification (JTGD 50-2017).

1. Permanent deformation of asphalt mixture layer

According to Table G.1.2, the reference equivalent temperature Tζ is 21.8deg.C, and the asphalt mixture layer permanent deformation equivalent temperature is 26.3deg.C calculated from formula (G.2.1). The reliability coefficient is 1.65.

The asphalt mixture layer was divided into 8 layers according to the layering method specified in item b.3.1, and each layer thickness (hi) is shown in table 3. And respectively calculating vertical compressive stress (Pi) of the top of each layering under the design load by utilizing an elastic layering system theory. From the formulas (b.3.2-3) and (b.3.2-4), d1= -3.54, d2=0.64 is calculated. The calculation results of d1 and d2 are taken into the formula (B.3.2-2), and the permanent deformation correction coefficient (kRi) of each layer can be obtained.

According to Table 3.0.6-1, the asphalt layer allowed set to 15.0 (mm), and each layered set (Rai) and corresponding rut set extremum was obtained using a programming solution method, as set forth in Table 2. The dynamic stability of the rutting test of each asphalt layer from top to bottom, calculated by the formula B.3.4, is larger than 6380 times/mm, 3289 times/mm, 2591 times/mm and 2245 times/mm.

2. Fatigue cracking of inorganic binder layers

According to the elastic layered system theory, the layer bottom tensile stress of the inorganic binder layer is 0.1003MPa. According to meteorological data, the freezing index F of the region where the engineering is located is 150.0 ℃ day, and the seasonal frozen soil region adjustment coefficient ka is 0.97 according to the table B.1.1. According to the formula (B.2.1-2), the on-site integrated correction coefficient is-1.446.

According to the region where the engineering is located, the temperature adjustment coefficient of the basic pavement structure is 1.32, and according to the material parameters of the primary pavement structure and the pavement structure layer, the temperature adjustment coefficient kT2 is 1.33. From table b.2.1-1, fatigue crack model parameters a=13.24, b=12.52 for inorganic binder stabilized pellets.

The integrated action times of the equivalent design axle load of the fatigue cracking of the inorganic binder layer is 1,498,499,410, and the integrated action times are obtained by back calculation according to the formula (B.2.1-1), and the bending ultimate strength of the inorganic binder stable material under the design structural layer is 1.03MPa.

3. Pavement low-temperature cracking

According to climate conditions, the low-temperature design temperature T of the region is-1.7 ℃. Roadbed type parameter b=3, low temperature cracking index requirement of 3.0 according to table 3.0.6-2, calculated by formula (b.5.1), stiffness modulus maximum value of 8751.46MPa for asphalt bending beam rheology test of the surface layer.

Step five: and (3) carrying out pavement material design, and meeting the requirement of the material design index in the fourth step.

The pavement material design index is the calculation result of the step four: the rutting test dynamic stability of each asphalt layer from top to bottom is greater than 6380 times/mm, 3289 times/mm, 2591 times/mm and 2245 times/mm. The flexural tensile ultimate strength of the inorganic binder stable material is 1.03MPa. The maximum value of creep stiffness modulus of the asphalt bending beam rheological test of the surface layer is 8751.46MPa, which is far greater than 300MPa of material design index, and the creep stiffness is less than 300MPa.

The above results are within the specification given for the design of the mix, and therefore the mix design needs to meet the above requirements.

Through the process, under the condition that the material index is limited at the maximum value, the utilization rate of the old road milling material can be increased, the use of different asphalt labels is enlarged, the aggregate which does not meet the requirement by a certain index can be demonstrated, the selectable range of the asphalt pavement material is increased, and the full utilization of resources is realized. In order to meet the requirement of pavement structure checking calculation, the existing standard design method selects the optimal pavement raw materials according to experience, and the conservation design causes material waste.

Of course, as shown in fig. 1, it may also include determining whether to perform the checking of the antifreeze thickness, if so, after determining the materials of each layer of the pavement, performing the checking of the antifreeze thickness, and if not, selecting the pavement forward design scheme.

The forward design method of the asphalt pavement facing the service performance, provided by the embodiment, takes semi-rigid base asphalt pavement design as an example, and is a domestic common pavement structure form; the inorganic binder stabilizing layer-by-layer bottom tensile stress and the permanent deformation of the asphalt mixture layer are used as design indexes, and the material performance indexes are determined, so that the asphalt pavement material design can be guided.

TABLE 1 Primary pavement structure

Structural layer braiding	Horizon layer	Type of material	Thickness (mm)	Minimum value (MPa)	Poisson
						1	Above it	Asphalt mixture	40.0	7500	0.25
2	Middle surface	Asphalt mixture AC-20	60.0	9000	0.25
						3	The following	Asphalt mixture AC-25	80.0	9000	0.25
4	Upper base	Asphalt mixture ATB-25	100.0	7000	0.40
						5	Medium base	Inorganic binder stabilizing material	180.0	7000	0.25
6	Lower base	Inorganic binder stabilizing material	180.0	7000	0.25
						7	Base	Inorganic binder stabilizing material	200.0	7000	0.25
8		Soil foundation		50	0.40

TABLE 2 calculation of permanent deformation of asphalt layer

While the present embodiment has been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the embodiments, the scope of which is defined by the claims and their equivalents.

It will be apparent to those skilled in the art that embodiments of the present disclosure may be provided as a method, system, or computer program product. Accordingly, the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present disclosure may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present disclosure is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The foregoing description of the preferred embodiments of the present disclosure is provided only and not intended to limit the disclosure so that various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

While the specific embodiments of the present disclosure have been described above with reference to the drawings, it should be understood that the present disclosure is not limited to the embodiments, and that various modifications and changes can be made by one skilled in the art without inventive effort on the basis of the technical solutions of the present disclosure while remaining within the scope of the present disclosure.

Claims

1. A forward design method of an asphalt pavement facing the service performance is characterized by comprising the following steps: the method comprises the following steps:

according to the determined design time limit equivalent design axle load accumulated action times and the primary pavement structure, referring to a table and a formula in the Highway asphalt pavement design Specification (JTGD 50-2017), calculating pavement structure mechanical response and asphalt pavement material design indexes, and determining a material index extremum, wherein the material index extremum is specifically as follows: permanent deformation of the asphalt mixture layer: determining a reference equivalent temperature according to a table G.1.2, calculating the equivalent temperature and the reliability coefficient of permanent deformation of the asphalt mixture layer by a formula G.2.1, dividing the asphalt mixture layer into 8 layers according to a layering method specified by a B.3.1, and calculating vertical compressive stress Pi at the top of each layer under the action of a design load by utilizing an elastic layered system theory respectively so as to obtain a permanent deformation correction coefficient kRi of each layer;

fatigue cracking of inorganic binder layer: according to elastic layered system theory, calculating to obtain the layer bottom tensile stress of the inorganic binder, according to meteorological data, obtaining a freezing index F of an area where an engineering is located, according to a table B.1.1, obtaining a seasonal frozen soil area adjustment coefficient ka, according to a formula B.2.1-2, obtaining a site comprehensive correction coefficient, according to the area where the engineering is located and a table G.1.2, obtaining a reference road surface structure temperature adjustment coefficient, according to a primary road surface structure and road surface structure layer material parameters, calculating to obtain a temperature adjustment coefficient kT2 according to a formula G.1.3-1, obtaining a fatigue cracking model parameter for the inorganic binder, designing an axle load cumulative action number according to the equivalent weight of the fatigue cracking of the inorganic binder layer, and reversely calculating according to a formula B.2.1-1, under the designed structural layer, obtaining the bending ultimate strength of the inorganic binder stable material;

pavement low-temperature cracking: obtaining a low-temperature design temperature T of a region where the road bed is located according to climate conditions, obtaining a low-temperature cracking index according to a table 3.0.6-2, and calculating a stiffness modulus maximum value of a surface layer asphalt bending beam rheological test according to a formula B.5.1;

according to the determined extreme value, determining pavement materials, and selecting a pavement forward design scheme by combining the set pavement structure;

the asphalt pavement material index is back calculated by utilizing an asphalt pavement structure design equation, and a material design index extremum is given; if the material index value is larger than the requirement of the specification on the material performance, the modulus of each layer needs to be adjusted, and if the material index value is smaller than the requirement of the specification on the material performance, the minimum value of the material design index is taken as the extremum of the material index.

2. The method for forward designing the asphalt pavement facing the service performance according to claim 1, which is characterized in that: and calculating the accumulated action times of equivalent design axle load on the design lane within the service life of the design according to the calculation method of annex A of the highway asphalt pavement design specification (JTGD 50-2017).

3. The method for forward designing the asphalt pavement facing the service performance according to claim 1, which is characterized in that: and determining the roadbed soil quality of the road location, the equivalent rebound modulus of the roadbed top surface and the local temperature and humidity conditions, and carrying out preliminary drawing of pavement structure combination and thickness of each structure layer according to the roadbed soil quality, the roadbed top surface equivalent rebound modulus and the local temperature and humidity conditions.

4. The method for forward designing the asphalt pavement facing the service performance according to claim 1, which is characterized in that:

according to the layering method of annex B of the highway asphalt pavement design specification (JTGD 50-2017), an asphalt mixture layer is divided into a plurality of layers, the thickness of each layer is preliminarily determined, the tensile stress of the bottom of an inorganic binder stabilizing layer and the vertical compressive stress of the top surface of each layer of the asphalt mixture layer are calculated by adopting an elastic layered continuous system theory under the action of double-circle uniform vertical load, and then the permanent deformation correction coefficient of each layer is obtained.

5. The method for forward designing the asphalt pavement facing the service performance according to claim 1, which is characterized in that: and judging whether to perform checking calculation of the anti-freezing thickness, if so, performing checking calculation of the anti-freezing thickness after determining materials of each layer of the pavement, and if not, selecting a pavement forward design scheme.

6. The forward design method of the asphalt pavement facing the service performance as defined in claim 4, wherein the method comprises the following steps: the initial modulus of elasticity is the minimum value specified in the highway asphalt pavement design Specification (JTGD 50-2017).

7. A computer-readable storage medium, characterized by: in which a plurality of instructions are stored, said instructions being adapted to be loaded and executed by a processor of a terminal device for the forward design method of an asphalt pavement for use performance according to any one of claims 1-6.

8. A terminal device, characterized by: comprising a processor and a computer-readable storage medium, the processor configured to implement instructions; a computer readable storage medium for storing a plurality of instructions adapted to be loaded by a processor and to perform the performance-oriented asphalt pavement forward design method of any one of claims 1-6.