A combined pavement structure and test method for deflection detection

Abstract

The present invention provides a combined pavement structure and test method for deflection detection, belonging to the technical field of cement concrete pavement disease detection. The present invention includes a surface layer plate, a base layer plate and a test tank. The test tank includes a base and baffles provided on two opposite sides of the base. The base layer plate and the surface layer plate are stacked on top of the base between the baffles. The surface layer plate is placed above the base layer plate, and the base layer plate is placed above the base. The surface layer plate and the base layer plate have various specifications, and the stacking methods of the surface layer plate and the base layer plate also have various combinations. By using surface layer plates, base layer plates and test tanks of different specifications to assemble a combined pavement structure, different types of road surface layer structures with voids can be constructed, and deflection basin values under various different void conditions can be obtained during the test for various pavement structure forms.

Description

Technical Field

[0001] The present invention belongs to the technical field of cement concrete pavement disease detection, and particularly relates to a combined pavement structure and test method for deflection detection. Background Art

[0002] A cement concrete pavement refers to a pavement with a cement concrete surface layer. Under the combined action of traffic loads and complex environments, local detachment occurs between the cement surface layer and the base layer, resulting in interlayer voids. If no measures are taken in time, the voids will develop rapidly, leading to diseases such as cracks, breakage, and faulting, and ultimately developing into the fracture of the entire surface layer slab, posing a hidden danger to traffic safety operation. Since interlayer voids occur inside the structure, it is impossible to determine the location of the voids through surface observation.

[0003] In the "Code for Field Testing of Highway Subgrade and Pavement" (JTG 3450 - 2019), a falling weight deflectometer is used for void detection. By measuring the deflection values at different positions of the cement concrete slab, the deflection ratios of the midpoint of the slab edge, the slab corner, and the slab center are calculated to determine whether there are voids under the slab. Research scholars use finite element software to simulate the deflection basin response of the pavement under the action of the deflectometer and analyze the response law of the deflection basin when interlayer voids occur. However, there are some problems in both field testing and numerical simulation: In field testing, it is impossible to determine whether there are voids inside the pavement structure, and the obtained deflection basin data is not representative; only the deflection basin data of one type of road structure can be obtained, and it is impossible to obtain the deflection data of multiple pavement structures at one time. The detection results are too single, and the test cost is relatively high; in field measurement, the heavy hammer continuously strikes the pavement, which may damage the original healthy state of the pavement. In numerical simulation, the finite element model is generally based on the elastic layer system theory, and the modeling is too theoretical, and the obtained deflection basin does not match the actual situation; for some large finite element models, the calculation process is relatively complex, the calculation cost is high, the model running time is long, and the calculation efficiency is low. Considering the above defects in field tests and numerical simulations, it is of great practical significance to invent an indoor deflection test device with low cost, convenient combination, and capable of simulating interlayer voids in various combination forms for related research. Summary of the Invention

[0004] Aiming at the above - mentioned technical problems, the present invention provides a combined pavement structure and test method that can simulate various road conditions and perform deflection detection under different conditions, solving the technical problems that it is impossible to judge whether the pavement structure is void and the measurement data is single during the actual pavement deflection detection process.

[0005] To achieve the purpose of the present invention, the technical solution of the present invention is as follows:

[0006] A combined pavement structure for deflection detection, characterized in that it includes a surface plate, a base plate and a test trough, the surface plate and the base plate are both rectangular structures, the length area of ​​the surface plate is twice the area of ​​the base plate, the test trough includes a base and baffles arranged on two opposite sides of the base, two surface plates stacked on each other and two base plates horizontally spliced ​​with each other are stacked and placed above the base in the test trough, the surface plate is placed above the base plate, the surface plate includes a standard plate and a steel plate, the standard plate is a cement concrete structure, and the steel plate is a steel plate with steel bars inside Concrete structure, the steel bar plate includes a single steel bar plate with one steel bar inside and a multi-steel bar plate with multiple steel bars, the spacing between the steel bars inside the multi-steel bar plate is equal, the surface layer plate can be combined into a combination of a standard plate and a single steel bar plate, a standard plate and a multi-steel bar plate, and two multi-steel bar plates when stacked and combined, the base plate includes a grooved plate and a grooveless plate with rectangular grooves, and the base plate can be spliced ​​into a combination of two grooved plates, a grooved plate and a grooveless plate, and two grooveless plates when spliced, and the surface layer plate and the base plate have the following five combinations when stacked and combined:

[0007] Category 1: Standard plates and single steel plate are stacked and combined, and then combined with base plates of any splicing method;

[0008] The second category: standard plates and single-layer reinforced plates are stacked and combined, and then combined with base plates of any splicing method;

[0009] The third type: two single-layer steel plates are stacked and combined and then combined with base plates of any splicing method;

[0010] The fourth category: any stacking combination of surface plates and two grooved plates that are butted against each other on one side of the groove;

[0011] The fifth category: any stacking combination of surface plates and two grooved plates spliced ​​with one side of the groove facing away from each other;

[0012] Furthermore, the diameters of the steel bars inside the steel bar plate have two specifications: 16 mm and 18 mm.

[0013] Furthermore, the steel bar plate can change the orientation of the steel bars by rotating in the horizontal direction.

[0014] Furthermore, the steel bars inside the steel plate are arranged at 1 / 3 of the distance from the bottom of the plate.

[0015] Further, the steel bar plate can change the position of the steel bars in the vertical direction by flipping in the vertical direction.

[0016] Further, the spliced parts of the base plates are not connected and form gaps therebetween.

[0017] Further, an experimental method for deflection detection based on the above combined pavement structure for deflection detection includes the following steps:

[0018] (1) Prepare surface course plates, base course plates and test troughs of different specifications;

[0019] (2) Assemble and splice the surface course plates and the base course plates and place them in the test trough to assemble a combined pavement structure;

[0020] (3) Place the combined pavement structure assembled from the surface course plates, the base course plates and the test trough in the accommodation trough preset on the ground;

[0021] (4) Drag the deflection detector to the upper part of the combined pavement structure to detect the deflection value;

[0022] (5) Adjust and replace the specifications and positional relationships of the surface course plates and the base course plates to detect the deflection values under different conditions.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] By assembling different specifications of surface course plates, base course plates and test troughs into a combined pavement structure, different types of road surface course structures and different situations of voids in the road water-stable base can be constructed, so that the deflection basin values in various different void situations can be obtained during the test, thereby providing data support and prior knowledge for analyzing whether there are voids inside the road surface in the on-site test. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of the combined pavement structure of the present invention;

[0026] Figure 2 is a schematic structural diagram of the standard plate in the surface course plate of the present invention;

[0027] Figure 3 is a schematic structural diagram of the single steel bar plate in the surface course plate of the present invention;

[0028] Figure 4 is a schematic structural diagram of the single-layer steel bar plate in the surface course plate of the present invention;

[0029] Figure 5 is a schematic structural diagram of the test trough of the present invention;

[0030] Figure 6 It is a schematic structural diagram of the grooved plate in the base plate of the present invention;

[0031] Figure 7 It is a schematic structural diagram of the non-grooved plate in the base plate of the present invention;

[0032] Figure 8 It is a schematic diagram of the first docking situation of the grooved plate of the present invention;

[0033] Figure 9 It is a schematic diagram of the second docking situation of the grooved plate of the present invention;

[0034] Figure 10 It is a schematic diagram of the third docking situation of the grooved plate of the present invention;

[0035] In the figure: 1 surface layer plate, 10 standard plates, 11 steel bar plates, 110 single steel bar plates, 111 single-layer steel bar plates, 2 base plates, 20 grooved plates, 200 grooves, 21 non-grooved plates, 3 test grooves, 30 bases, 31 baffles, 4 steel bars, 5 gaps. Specific implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] Refer to Figure 1-10As shown in the figure, the present invention provides a combined pavement structure for deflection detection, including a surface layer plate 1, a base layer plate 2 and a test groove 3. The length of the base layer plate 2 is half of the length of the surface layer plate 1. The surface layer plate 1 is used to simulate the road cement concrete surface layer, the base layer plate 2 is used to simulate the water-stabilized base layer of the road, and the test groove 3 is used to support and limit the stacking and assembly of the surface layer plate 1 and the base layer plate 2. The test groove 3 includes a base 30 and baffles 31 arranged on two opposite side edges of the base 30. The base layer plate 2 and the surface layer plate 1 are stacked on the base 30. When stacking and combining, two mutually stacked surface layer plates 1 and two mutually horizontally spliced base layer plates 2 are stacked above the base 30 in the test groove 3. The surface layer plate 1 is placed above the base layer plate 2, and the base layer plate 2 is placed above the base 30, so as to assemble a complete pavement structure. The surface layer plate 1 includes a standard plate 10 and a steel bar plate 11. The standard plate 10 is a structure made of cement concrete, and the steel bar plate 11 is a reinforced concrete structure with steel bars 4 arranged inside. The steel bar plate 11 includes a single steel bar plate 110 with one steel bar 4 arranged inside and multiple steel bar plates 111 with multiple steel bars arranged inside. The spacing between the steel bars 4 inside the multiple steel bar plates 111 is equal. When the surface layer plates 1 are stacked and combined, they can be combined into combinations of standard plates and single steel bar plates, standard plates and multiple steel bar plates, and two multiple steel bar plates. According to the Highway Cement Concrete Pavement Design Specification (JTG D40-2011), in this application, the designed size of the surface layer plate 1 is a cuboid structure of 300*300*20 cm. The number of steel bars 4 inside the multiple steel bar plates 111 is two cases of 6 and 11. The spacing between the two steel bars is two cases of 150 mm and 200 mm. The diameters of the steel bars 4 are 16 mm and 18 mm. The steel bars 4 inside the steel bar plate 11 are arranged at 1 / 3 from the bottom of the plate. According to the above steel bar sizes and quantity specifications, the steel bar plate 11 can be prepared into the following several cases:

[0038] The first case: One steel bar with a diameter of 16 mm is arranged inside the steel bar plate;

[0039] The second case: One steel bar with a diameter of 18 mm is arranged inside the steel bar plate;

[0040] The third case: n steel bars with a diameter of 16 mm and a spacing of d are arranged inside the steel bar plate;

[0041] The fourth case: n steel bars with a diameter of 18 mm and a spacing of d are arranged inside the steel bar plate.

[0042] Wherein, the value of n is 6 and 11, and the value of d is 150 mm and 200 mm.

[0043] The base plate 2 includes a grooved plate 20 and a non-grooved plate 21. The grooved plate 20 is provided with a rectangular groove 200 in the middle part of the upper edge of the base plate 2. The groove 200 on the grooved plate 20 can simulate the situation that the water-stable base under the road surface layer is emptied. When the base plate 2 is arranged, two base plates 2 need to be spliced ​​and combined and then placed on the base 30. When splicing, any two of the grooved plates 20 and the non-grooved plates 21 can be combined. For example, by connecting the two sides of the grooved plates 20 provided with the rectangular groove 200 to each other, a relatively large Grooves; grooves 200 with different positional relationships can be formed by splicing and combining the grooved plate 20 with the grooveless plate 21 or rotating the grooved plate 20 180° in the horizontal direction, so as to simulate the hollowing out of the road water-stable base layer caused by the grooves 200 at different positions and different sizes; by splicing and combining two grooveless plates 21, it is possible to simulate the situation that the road is not hollowed out, and because the contact part of the base plate 2 is not completely sealed when it is docked, a gap 5 will be formed, and this gap 5 can be used to detect the deflection value when cracks appear in the base layer due to hollowing out.

[0044] The surface plates and base plates can be combined in the following five ways when stacking:

[0045] The first category: the standard plate 10 and the single steel bar plate 110 are stacked and combined, and then combined with the base plate 2 of any splicing method;

[0046] The second category: the standard plate 10 and the single-layer steel plate 111 are stacked and combined, and then combined with the base plate 2 of any splicing method;

[0047] The third category: two single-layer steel bar plates 111 are stacked and combined and then combined with a base plate 2 of any splicing method;

[0048] The fourth category: a combination of two grooved plates 20 in which the surface plate 1 of any stacking combination is butted against one side of the groove and spliced ​​with each other;

[0049] The fifth category: any stacking combination of the surface plate 1 and the two grooved plates 20 spliced ​​together with one side of the groove facing away from each other;

[0050] When the above-mentioned top plate is combined with the base plate, the direction of the steel bar can be changed by rotating the steel plate in the horizontal direction, or the position of the steel bar in the vertical direction can be changed by flipping the steel plate in the vertical direction, thereby achieving the purpose of changing the road surface structure.

[0051] Example

[0052] According to the combination of the surface layer plates 1 and the base layer plates 2 of the above different specifications and types and the adjustment of the positional relationship, the void conditions under various road conditions can be simulated, so that the deflection values under different road void conditions can be detected. Some representative embodiments will be exemplified below for illustration:

[0053] Embodiment 1

[0054] After combining the standard plate 10 and the steel bar plate 11 and placing them on the base layer plate 2, the standard plate 10 is placed above the steel bar plate 11. The steel bar plate 11 can be selected from either the first or the second type. The base layer plate 2 can be selected in any combination method. After the standard plate 10, the steel bar plate 11, and the base layer plate 2 are stacked and placed to measure the deflection value, then the steel bar plate 11 is rotated by 90° and measured again. Through this combination method, the deflection values of the steel bars 4 inside a single steel bar plate 110 in two different directions can be detected.

[0055] Embodiment 2

[0056] After stacking and combining the standard plate 10 and the steel bar plate 11 and placing them on the base layer plate 2, the standard plate 10 is placed on the steel bar plate 11. The steel bar plate 11 is selected as the third type. The number of steel bars n in the steel bar plate 11 is 11, and the spacing d is 200. The base layer plate 2 can be selected in any combination method. After the deflection value detection is completed, the third steel bar plate is taken out and the fourth steel bar plate is put in. The number of steel bars 4 and the spacing in the fourth steel bar plate are 11 and 200 respectively. Through this combination method, the deflection values of the single-layer steel bar plate 111 with different diameters of the steel bars 4 can be detected.

[0057] Embodiment 3

[0058] After stacking and combining the standard plate 10 and the steel bar plate 11 and placing them on the base layer plate 2, the standard plate 10 is placed on the steel bar plate 11. The steel bar plate 11 is selected as the third or the fourth type. The number of steel bar plates 11 and the spacing are 11 and 200 respectively. The base layer plate 2 can be selected in any combination method. After the deflection value detection is completed, the steel bar plate 11 is flipped by 180°, and the deflection value is detected again. At this time, the position of the steel bar 110 inside the steel bar plate 11 in the vertical direction is at 2 / 3 of the distance from the plate bottom. Through this combination method, the deflection values of the single-layer steel bar plate 11 under different positions of the steel bar arrangement can be detected.

[0059] Embodiment 4

[0060] Stack and combine the standard plate 10 and the steel bar plate 11 and place them on the base plate 2. The standard plate 10 is placed on the steel bar plate 11. The third or fourth type of steel bar plate 11 is selected. The number of steel bars 4 and the spacing value in the steel bar plate 11 are 11 and 200 respectively. Any combination method of the base plate 2 is selected. After the deflection value detection is completed, replace the steel bar plate 11 with a steel bar plate with 11 bars and a spacing of 150. Through this combination method, the deflection values of the steel bars 4 inside the steel bar plate 11 under different spacings can be detected.

[0061] Example Five

[0062] Stack and combine the third type of steel bar plate and the fourth type of steel bar plate and place them on the base plate 2. The number of bars in both the third type of steel bar plate and the fourth type of steel bar plate is 11, and the spacing value is 200. Any combination method of the base plate 2 is selected. Through this combination method, the deflection value in the case of a double-layer steel bar plate can be detected.

[0063] Example Six

[0064] Stack and combine the third type of steel bar plate and the fourth type of steel bar plate and place them on the base plate. The third type of steel bar plate is placed above the fourth type of steel bar plate. When placing the third type of steel bar plate, the side of the plate surface closer to the steel bars faces downward, and when placing the fourth type of steel bar plate, the side of the plate surface closer to the steel bars faces upward. Any combination method of the base plate 2 is selected. The number of steel bars inside the third type of steel bar plate and the fourth type of steel bar plate is 11, and the spacing between the steel bars is 200 mm. Through this combination method, the deflection values of the double-layer steel bar plate under different layout positions of the steel bars can be detected.

[0065] Example Seven

[0066] Dock the sides of the two grooved plates 20 in the base plate 2 with grooves 200 facing each other and place them above the base 30. Then stack any two surface plates 1 on the base plate 2. Through this combination method, the size of the grooves on the base plate 2 can be changed, so that the deflection values of the base plate 2 under different forms of voids can be detected.

[0067] Example Eight

[0068] Join and place the sides of the two grooved plates 20 in the base plate 2 with grooves 200 facing away from each other above the base 30. Then stack any two surface plates 1 on the base plate 2. Through this combination method, the position of the groove 200 on the base plate 2 can be changed, so that the deflection values of the base plate 2 under different positions of voids can be detected.

[0069] When conducting the deflection value detection test under the condition of pavement voiding by using the combined pavement structure provided by the present invention, it is mainly carried out through the following steps:

[0070] (1) First, prepare surface course plates 1, base course plates 2 and test troughs 3 of different specifications;

[0071] (2) Assemble and splice the surface course plate 1 and the base course plate 2 and place them in the test trough 3 to assemble a combined pavement structure;

[0072] (3) Place the combined pavement structure assembled by the surface course plate 1, the base course plate 2 and the test trough 3 into the accommodation trough preset on the ground by a hoisting device, and the size of the accommodation trough is adapted to that of the test trough 3;

[0073] (4) Drag the deflectometer above the combined pavement structure to detect the deflection value, and record the deflection value under the pavement structure at this time;

[0074] (5) Use the hoisting device to adjust and replace the specifications and positional relationships of the surface course plate 1 and the base course plate 2 to detect the deflection values under different conditions.

[0075] By using surface course plates, base course plates and test troughs of different specifications to assemble a combined pavement structure, the present invention can construct different types of road surface course structures and different situations of voiding in road cement stabilized bases, so as to obtain the deflection basin values under various voiding conditions in various pavement structure forms during the test, and thus provide data support and prior knowledge for analyzing whether there is voiding inside the pavement in on-site testing.

[0076] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principle and spirit of the present invention, various changes, modifications, substitutions and variations made to these embodiments still fall within the protection scope of the present invention.

Claims

1. A combined pavement structure for deflection detection, characterized in that: It includes a surface layer plate (1), a base layer plate (2) and a test tank (3). The area of the surface layer plate (1) is twice that of the base layer plate (2). The test tank (3) includes a base (30) and baffles (31) arranged on two opposite side edges of the base (30). Two mutually stacked surface layer plates (1) and two mutually horizontally spliced base layer plates (2) are stacked above the base (30) in the test tank (3). The surface layer plate (1) is placed above the base layer plate (2). The surface layer plate (1) includes a standard plate (10) and a steel bar plate (11). The standard plate (10) is a cement concrete structure, and the steel bar plate (11) is a reinforced concrete structure with steel bars (4) inside. The steel bar plate (11) includes a single steel bar plate (110) with one steel bar (4) inside and a multi-steel bar plate (111) with multiple steel bars (4). The spacing between the steel bars (4) inside the multi-steel bar plate (111) is equal. When the surface layer plates are stacked and combined, they are combined in the ways of standard plate and single steel bar plate, standard plate and multi-steel bar plate, and two multi-steel bar plates. The base layer plate (2) includes a grooved plate (20) with a rectangular groove (200) and a non-grooved plate (21). The splicing form of the base layer plate (2) is two grooved plates (20), a grooved plate (20) and a non-grooved plate (21), and two non-grooved plates (21). When the surface layer plate (1) and the base layer plate (2) are stacked and combined, there are the following five types of combination methods: The first type: The standard plate (10) and the single steel bar plate (110) are stacked and combined and then combined with the base layer plate (2) in any splicing method; The second type: The standard plate (10) and the multi-steel bar plate (111) are stacked and combined and then combined with the base layer plate (2) in any splicing method; The third type: Two multi-steel bar plates (111) are stacked and combined and then combined with the base layer plate (2) in any splicing method; The fourth type: The surface layer plate (1) in any stacking and combination method is combined with two grooved plates (20) whose grooves are spliced with one side facing each other; The fifth type: The surface layer plate (1) in any stacking and combination method is combined with two grooved plates (20) whose grooves are spliced with one side facing away from each other.

2. The combined pavement structure for deflection value detection according to claim 1, characterized in that: The diameters of the steel bars (4) inside the steel bar plate (11) have two specifications of 16mm and 18mm.

3. The combined pavement structure for deflection value detection according to claim 1, characterized in that: The steel bar plate (11) can change the orientation of the steel bar (4) by rotating in the horizontal direction.

4. The combined pavement structure for deflection value detection according to claim 1, characterized in that: The steel bars (4) inside the steel bar plate (11) are arranged at 1 / 3 of the distance from the bottom of the plate.

5. The combined pavement structure for deflection value detection according to claim 4, characterized in that: The steel bar plate (11) can change the position of the steel bar (4) in the vertical direction by flipping in the vertical direction.

6. The combined pavement structure for deflection detection according to claim 1, characterized in that: The spliced parts of the base layer plate (2) are not connected and form a gap (5) therebetween.

7. An experimental method for deflection detection using the combined pavement structure for deflection detection according to any one of claims 1-6, characterized in that: It includes the following steps: (1) Prepare surface layer plates (1), base layer plates (2) and test tanks (3) of different specifications; (2) Assemble and splice the surface layer plate (1) and the base layer plate (2) and place them in the test tank (3) to assemble a combined pavement structure; (3) Place the combined pavement structure assembled by the surface layer plate (1), the base layer plate (2) and the test tank (3) in the accommodation tank preset on the ground; (4) Drag the deflection detector above the combined pavement structure to detect the deflection value; (5) Adjust and replace the specifications and positional relationships of the surface layer plate (1) and the base layer plate (2) to detect the deflection values under different conditions.

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