A method for grooving the surface of CRC layer of composite pavement

Abstract

The invention discloses a composite pavement CRC layer surface groove method, which comprises the following steps: S1, determining composite pavement structure design parameters; S2, establishing a composite pavement finite element model according to the composite pavement structure design parameters of step S1; S3, calibrating the composite pavement finite element model; S4, calculating the composite pavement interlayer shear equivalent shear angle using the calibrated composite pavement finite element model data; S5, obtaining the composite pavement CRC layer surface groove angle according to the composite pavement interlayer shear equivalent shear angle of step S4, thereby determining the composite pavement CRC layer surface groove. The invention can design a surface groove that produces less cement concrete waste and is suitable for the composite pavement CRC layer.

Description

Technical Field

[0001] The invention belongs to the field of urban road composite pavement, and in particular relates to a method for grooving the surface of a composite pavement CRC layer. Background Art

[0002] Composite pavement has the advantages of high durability, strong bearing capacity and long service life of concrete pavement. It also has the characteristics of smooth surface, comfortable driving, easy maintenance and low noise of asphalt concrete pavement. It is a road structure form with good development prospects.

[0003] In order to ensure that the AC layer and CRC layer of the composite pavement have sufficient shear strength, it is usually necessary to roughen the surface of the CRC layer, and grooving is one of the commonly used roughening methods for the surface of the CRC layer of the composite pavement. The existing groove cross-section is generally rectangular, but the rectangular cross-section will produce more cement concrete waste and is difficult to completely rinse, affecting the shear strength and bonding strength between the CRC surface and the AC layer. In addition, there is a certain diffusion angle when the traffic load is transmitted from the road surface downward, and the rectangular groove cross-section cannot effectively buffer the directional load transmitted from the road surface to the top surface of the CRC layer, resulting in a greater impact of the load on the interlayer, which is not conducive to the stability of the interlayer bonding. Therefore, it is necessary to design a new CRC layer surface groove.

[0004] The current CRC layer surface grooving is mainly completed based on the "Technical Specifications for Highway Cement Concrete Pavement Construction" (JTG / T F30-2014) and "Urban Road Engineering Construction and Quality Acceptance Code" (CJJ 1-2008) and other specifications. It only stipulates the groove depth, groove width and groove spacing of rectangular grooves, but does not stipulate other shapes of groove sections, nor does it stipulate the selection of groove sections from the perspective of load diffusion. Summary of the invention

[0005] The purpose of the present invention is to provide a method for grooving the surface of a composite pavement CRC layer, which can design a method that produces less cement concrete waste and is suitable for grooving the surface of a composite pavement CRC layer.

[0006] The technical solution adopted by the present invention is:

[0007] A method for grooving the surface of a composite pavement CRC layer comprises the following steps:

[0008] S1. Determine the design parameters of the composite pavement structure;

[0009] S2, establishing a composite pavement finite element model according to the composite pavement structure design parameters of step S1;

[0010] S3, calibrating the composite pavement finite element model;

[0011] S4, calculating the shear equivalent shear angle between layers of the composite pavement using the calibrated composite pavement finite element model data;

[0012] S5. Obtain the surface groove angle of the composite pavement CRC layer according to the shear equivalent shear angle between the composite pavement layers in step S4, thereby determining the surface groove of the composite pavement CRC layer.

[0013] According to the above scheme, in step S1, the composite pavement structure design parameters include traffic load, AC layer thickness, AC layer modulus, AC layer Poisson's ratio, CRC layer thickness, CRC layer modulus, CRC layer Poisson's ratio, soil base modulus, soil base Poisson's ratio, and horizontal force coefficient.

[0014] According to the above scheme, in step S2, based on the mechanical analysis of the composite pavement, a finite element model of the composite pavement is established based on the elastic layered theoretical system.

[0015] According to the above scheme, in step S3, the method for calibrating the composite pavement finite element model is:

[0016] By burying sensors in the actual road to collect stress and strain data, the data is compared and analyzed with the finite element calculation results under the same working conditions, the finite element parameters are adjusted, and the finite element model is calibrated.

[0017] According to the above scheme, in step S4, the method for calculating the interlayer shear equivalent shear angle of the composite pavement using the calibrated composite pavement finite element model data is:

[0018] According to the calculation results of the finite element model, the equivalent shear angle of compression-shear stress under the combined action of vertical compression stress and shear stress is determined.

[0019] The interlayers under the action of traffic load are subjected to the combined effect of shear stress and vertical compressive stress. The vertical compressive stress and shear stress form a compression-shear force. The angle between the direction of this force and the vertical direction is the equivalent shear angle of the composite pavement interlayer shear resistance, which is obtained through finite element calculation results.

[0020] According to the above scheme, the groove surface angle of the CRC layer of the composite pavement is equal to the equivalent shear angle between the composite pavement layers.

[0021] According to the above scheme, the grooves on the surface of the CRC layer of the composite pavement are triangular in shape.

[0022] According to the above scheme, the horizontal force coefficient is the ratio of the horizontal load to the vertical load, which is determined based on engineering experience and, if necessary, by test data.

[0023] The beneficial effects of the present invention are:

[0024] The present invention is based on mechanical analysis and determines the equivalent shear angle between layers of the composite pavement through finite element calculation. The surface groove angle of the CRC layer of the composite pavement is designed according to the equivalent shear angle, thereby improving the roughening effect of the groove on the surface of the CRC layer, improving the shear strength between layers of the composite pavement, reducing the disease problems of the composite pavement caused by insufficient shear strength between layers, and at the same time reducing the waste residue generated by the rectangular cross-section grooves, reducing the influence of the rectangular cross-section grooves on the CRC layer, and achieving significant social and economic benefits.

[0025] The present invention reduces the influence of the load transferred to the surface of the CRC layer on the interlayer structure, improves the bonding strength between the CRC layer and the AC layer, and fills the deficiency of the current specification on the groove type of the CRC layer.

[0026] The angle of the groove surface on the CRC layer is obtained based on the equivalent shear angle between the layers of the composite pavement, which can improve the shear strength between the layers and reduce the angle of the interlayer disturbance.

[0027] The invention is simple and highly operable, and can be widely used in composite road rutting prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0029] Figure 1 It is a schematic diagram of the process of the surface groove cutting method of the CRC layer of the composite pavement;

[0030] Figure 2 It is the field measured value of the actual composite pavement CRC road slab;

[0031] Figure 3 is the calculated value of the composite pavement finite element model;

[0032] Figure 4 is the equivalent interlaminar shear angle calculated by the finite element model;

[0033] Figure 5 It is a groove type on the surface of the CRC layer. DETAILED DESCRIPTION

[0034] In order 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 embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] A composite road adopts the AC+CRC structure. The AC layer is 7.5 cm thick, with a rebound modulus of 8500 MPa and a Poisson's ratio of 0.25. The CRC layer is 30 cm thick, with a rebound modulus of 30000 MPa and a Poisson's ratio of 0.15. The subgrade rebound modulus is 80 MPa and a Poisson's ratio of 0.4. The vehicle load is 0.7 MPa according to the specification, and the horizontal force coefficient is 0.5 based on experience. For comparison, the horizontal force coefficient is taken as 0 and 1 at the same time for calculation.

[0036] The finite element model was established using BISAR3.0 software, and the parameters of the finite element model are as above.

[0037] In the actual composite road, strain sensors are embedded on the top and bottom of the CRC slab to collect the strain data of the top and bottom of the slab under the action of a vehicle with an axle load of 243kN, and then compared and calibrated with the calculation results of the finite element model. Figure 2 and Figure 3 It can be seen that the model calculation values ​​are consistent with the field measured values, and the influence law and range of load on CRC plate strain are close to the measured data.

[0038] Calculate the equivalent shear angle between the composite pavement layers. Use the calibrated finite element model to calculate the equivalent shear angle. Based on the calculation results and reference to the specifications, the equivalent shear angle of 22.1° at the longitudinal position of 0.1m is used as the design basis for the groove surface angle of the CRC layer. Figure 4 shown.

[0039] Design the groove surface angle of the composite pavement CRC layer. The groove type of the CRC layer surface is designed according to the equivalent shear angle. The design principle is that the groove surface angle of the CRC layer surface is equal to the equivalent shear angle, that is, the angle between the groove surface of the CRC layer surface and the horizontal direction is 22.1°. The groove on the composite pavement CRC layer surface is triangular in shape, that is, the cross section of the groove on the composite pavement CRC layer surface is triangular, such as Figure 5 shown.

[0040] The present invention supplements the CRC surface grooving method of the composite pavement on the basis of the existing design specifications, improves the roughening effect of the grooving on the surface of the CRC layer, improves the shear strength between layers of the composite pavement, reduces the disease problems of the composite pavement caused by insufficient shear strength between layers, and at the same time reduces the waste residue generated by grooving, reduces the impact of grooving on the CRC layer, and has significant social and economic benefits.

[0041] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A method for grooving the surface of a composite pavement CRC layer, characterized in that: The steps include: S1. Determine the design parameters of the composite pavement structure; S2, establishing a composite pavement finite element model according to the composite pavement structure design parameters of step S1; S3, calibrating the composite pavement finite element model; S4, calculating the shear equivalent shear angle between layers of the composite pavement using the calibrated composite pavement finite element model data; The groove pattern of the CRC layer surface is designed according to the equivalent shear angle. The design principle is that the groove surface angle of the CRC layer surface is equal to the equivalent shear angle. S5. According to the shear equivalent shear angle between the composite pavement layers in step S4, the groove surface angle of the composite pavement CRC layer surface is obtained, that is, the groove surface angle of the composite pavement CRC layer surface is the angle between the groove surface of the CRC layer surface and the horizontal direction, thereby determining the groove on the composite pavement CRC layer surface.

2. The method for grooving the surface of a composite pavement CRC layer according to claim 1, characterized in that: In step S1, the composite pavement structure design parameters include traffic load, AC layer thickness, AC layer modulus, AC layer Poisson's ratio, CRC layer thickness, CRC layer modulus, CRC layer Poisson's ratio, soil base modulus, soil base Poisson's ratio, and horizontal force coefficient.

3. The method for grooving the surface of a composite pavement CRC layer according to claim 1, characterized in that: In step S2, a composite pavement finite element model is established based on the elastic layered theory system.

4. The method for grooving the surface of a composite pavement CRC layer according to claim 1, characterized in that: In step S3, the method for calibrating the composite pavement finite element model is: By burying sensors in the actual road to collect stress and strain data, the data is compared and analyzed with the finite element calculation results under the same working conditions, the finite element parameters are adjusted, and the finite element model is calibrated.

5. The method for grooving the surface of a composite pavement CRC layer according to claim 1, characterized in that: In step S4, the method for calculating the shear equivalent shear angle between the composite pavement layers is: According to the calculation results of the finite element model, the equivalent shear angle of compression-shear stress under the combined action of vertical compression stress and shear stress is determined.

6. The method for grooving the surface of a composite pavement CRC layer according to claim 1 or 5, characterized in that: The groove angle of the CRC layer surface of the composite pavement is equal to the equivalent shear angle between the composite pavement layers.

7. The method for grooving the surface of a composite pavement CRC layer according to claim 1 or 5, characterized in that: The grooves on the surface of the composite pavement CRC layer are in a triangular shape.

8. The method for grooving the surface of a composite pavement CRC layer according to claim 2, characterized in that: The horizontal force coefficient is the ratio of the horizontal load to the vertical load.

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