Pavement texture depth measurement apparatus and measurement method

Abstract

A pavement texture depth measurement apparatus and measurement method, which effectively solve the problems of a sand-spreading method having a relatively large error and a laser method having a principle defect. Compared with a traditional a sand scraping method, carrying fine sand by means of water flows into pavement cracks make the pavement gaps be more fully filled; compared with a traditional manner in which the amount of sand is measured in advance and in which scraping and leveling are performed, using the amount of fine sand reduced in a sand storage chamber (4) as the volume of the fine sand in the pavement gaps eliminates the artificial subjective judgment for a scraping and leveling state, and therefore the amount of sand is more rationally measured. In addition, the amount of sand reduced in the sand storage chamber (4) is calculated by means of the change in air pressure, such that a tiny change in the volume can be accurately measured; moreover, since the spreading area of the fine sand is defined as a constant value by using a cylinder body (1), a more rational and accurate amount and area of sand can be obtained, and thus a more accurate measurement result is obtained.

Description

A road surface structure depth detection device and detection method thereof Technical Field

[0001] The present invention relates to the field of road detection, in particular to a road surface structure depth detection device and a detection method thereof. Background Art

[0002] The structural depth refers to the average depth of open pores on the uneven road surface of a certain area, which is mainly used to evaluate the macro-roughness, drainage performance and skid resistance of the road surface. The current detection method is the sand spreading method, which is to measure a certain volume of fine sand and spread it flat on the road surface with a sand scraper so that the sand particles are embedded in the cracks in the road surface. The ratio of the volume of fine sand to the paving area is the structural depth. It can be seen that the accuracy of the structural depth detection value mainly depends on two parameters. One is the volume of fine sand embedded in the cracks in the road surface. The accuracy of the volume is affected by two factors: the filling degree of the cracks by the sand particles and whether the road surface is paved. It is difficult to make the sand particles completely fill the road surface by scraping the sand. The first is the surface gap, and the judgment of whether it is paved is too subjective, so the rationality and accuracy of the volume of fine sand embedded in the gap determined by the current method are poor; the second is the surface area of ​​paving. Paving is required to be paved in a circular shape as much as possible. In the past, it was mostly manual paving, relying on subjective judgment. Currently, there are many electric paving equipment, such as the invention patent with application number 202211552100.6, which uses a motor to drive the sand spreading plate to rotate on a fixed axis, which can spread the fine sand into a relatively regular circle, but it is only an improvement over manual paving. In addition, the definition of the paving boundary during measurement is relatively vague, so the problem of poor accuracy of the paving area has not been fundamentally solved.

[0003] In view of the poor accuracy of the sand spreading method, some laser measuring instruments have emerged, such as the invention patent application number: CN200610105075.1, the invention patent application number: CN201410281694.0, etc., which use lasers to measure the vertical distance between the road surface and the probe within a certain range or use a three-dimensional laser scanner to establish a three-dimensional model of the road surface, and then calculate the structural depth through a processor. The essence of this type of laser-based equipment is to scan the image or data of the gap openings exposed in the road surface. However, the road surface cracks are not all exposed directly below the gap openings, but extend and distribute under the road surface in irregular shapes such as tilted and tortuous shapes. A considerable portion of the pores cannot be scanned from the gap openings, so there are defects in its principle. Summary of the Invention

[0004] The present invention provides a road surface structure depth detection device and a detection method thereof, aiming to solve the problems of large error in the sand spreading method and principle defects in the laser method.

[0005] A road surface structure depth detection device includes a cylinder with an open lower end and a closed upper end, a piston is installed in the cylinder, a closed air cavity is formed above the piston, a sand storage chamber is below the piston, a radial limit bolt is installed on the side wall of the cylinder, the inner end of the limit bolt extends to the bottom of the piston, and can limit the initial position of the piston, a first air intake pipe, an exhaust pipe and a pressure gauge are installed on the top of the air cavity, an air intake check valve is installed on the first air intake pipe, and a first switch is installed on the exhaust pipe; it also includes a flat pad, which is placed under the cylinder to close the cylinder mouth, the sand storage chamber is filled with fine sand, and the side of the sand storage chamber is A common water and gas pipe and a second air inlet pipe are installed on the wall, a second switch is installed on the common water and gas pipe, and a third switch is installed on the second air inlet pipe; a drainage groove is opened on the lower end surface of the cylinder, and a pipe sleeve is coaxially sleeved on the lower end of the outer wall of the cylinder. The pipe sleeve fits the outer wall of the cylinder and can move up and down. When the pipe sleeve moves down to the lower end and is flush with the lower end of the cylinder, the drainage groove is closed, and when the pipe sleeve moves up, the drainage groove is opened; a rotating shaft is installed at the axis of the cylinder, the upper end of the rotating shaft passes through the cylinder and is connected to a drive motor, the lower end of the rotating shaft penetrates the piston and is installed with multiple radial sand scraping plates, and the bottom surface of the sand scraping plate is flush with the lower end surface of the cylinder.

[0006] The pad is formed by stacking a first pad and a second pad, the thickness of the first pad is 5 to 10 mm, and the second pad is overlapped and stacked on the first pad, the thickness of the second pad is 0.1 to 0.3 mm.

[0007] The pipe sleeve is provided with a vertical avoidance groove, and the water-gas common pipe and the second air inlet pipe pass through the avoidance groove without affecting the up-and-down movement of the pipe sleeve.

[0008] The cross section of the sand scraping plate is wedge-shaped, with the tip of the wedge facing the direction of rotation.

[0009] The lower end of the inner wall of the cylinder is provided with a sand filter net.

[0010] The outer wall of the cylinder is equipped with a vibration motor.

[0011] A detection method for a road surface structure depth detection device comprises the following steps:

[0012] Step 1: Dry the fine sand to be tested with hot air;

[0013] Step 2: With the mouth of the cylinder facing upward, fill the sand storage chamber of the cylinder with dried fine sand and cover the mouth of the cylinder with the second pad and the first pad in sequence. Then, turn the cylinder over and place it stably at the detection point. At this time, the inner end of the limit bolt extends below the piston to limit the piston. When the piston contacts the limit bolt, the volume of the air cavity is V0, which is a constant value. Inflate the air cavity through the first air inlet pipe until the air cavity reaches the set positive pressure value P0 and then stop inflating.

[0014] Twist the limit bolt outward to release the limit on the piston, then start the vibration motor. Continue vibrating until the pressure gauge reading is stable for more than 1 minute, then stop. Record the pressure gauge reading P1 at this time.

[0015] Step 3: slowly pull out the first pad, after which the second pad is placed against the ground, and then slowly pull out the second pad;

[0016] Step 4: Connect the water and air common pipe to the pressure water source, open the second switch to inject water into the sand storage chamber, and the water will seep into the road surface. At the same time, start the drive motor to drive the sand scraper to rotate. Continue injecting water and scraping sand until the pressure gauge reading is stable for more than 1 minute.

[0017] Step 5: Stop water injection, turn off the motor, pull up the pipe sleeve to open the drainage trough, and drain the free water in the sand storage chamber from the drainage trough. Then, connect the second air inlet pipe to the hot air source, turn on the third switch and the second switch, and let hot air into the sand storage chamber to dry the fine sand. The hot air is discharged from the water and air common pipe. The drying degree of the fine sand is determined by detecting the humidity of the discharged hot air. When the drying degree of the fine sand reaches the same as that in step 1, the drying is stopped.

[0018] Step 6: Start the vibration motor and vibrate until the pressure gauge reading is stable for more than one minute, then stop and record the pressure gauge reading P2 at this time;

[0019] Step 7: Calculate the structural depth TD, for the air cavity, according to the gas equation PV=nRT;

[0020] Where P is pressure;

[0021] V is volume;

[0022] n is the molar mass, and the gas in the cavity is constant, so n is a constant at this time;

[0023] R is a constant;

[0024] T is the absolute temperature, which is also a constant at this time;

[0025] Therefore, P0V0=P1V1=P2V2=constant;

[0026] Where V1 is the volume of the air cavity when recording P1;

[0027] V2 is the volume of the air cavity when P2 was recorded;

[0028] From this formula, we can calculate V1=P0V0 / P1 and V2=P0V0 / P2, and calculate the volume difference V 差 =V2-V1. Since the diameter of the cylinder is the same at the top and bottom, the volume of fine sand in the sand storage chamber is reduced, that is, the volume of fine sand that penetrates into the cracks in the road surface is V. 沙 = V 差 =V2-V1;

[0029] Then the structural depth of the road surface TD=V 沙 / S=(V2-V1) / S=(P0V0 / P2-P0V0 / P1) / S, where S is the inner diameter cross-sectional area of ​​the cylinder.

[0030] Before step 2, the road surface at the monitoring point is washed with a high-pressure water gun and then blown dry with hot air.

[0031] In step 2, P0 is 1.3 to 1.5 atmospheres.

[0032] The present invention improves the sand spreading method, has no principle defects, and can obtain more reasonable and accurate sand quantity and area, thereby obtaining more accurate detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a front cross-sectional view of the present invention in step 2. FIG.

[0034] FIG2 is a front cross-sectional view of the present invention in step six.

[0035] FIG3 is an enlarged view of position A in FIG1 .

[0036] FIG4 is a perspective view of the lower end of the cylinder.

[0037] FIG5 is a perspective view of a sand scraper. DETAILED DESCRIPTION

[0038] In conjunction with the accompanying drawings, the road surface structure depth detection device includes a cylinder 1 with an open lower end and a closed upper end. A piston 2 is installed in the cylinder 1, and a sealing ring is installed between the piston 2 and the cylinder 1. A closed air cavity 3 is formed above the piston 2, and a sand storage chamber 4 is below the piston 2. A radial limit bolt 5 is installed on the side wall of the cylinder 1. The inner end of the limit bolt 5 extends below the piston 2 and can limit the initial position of the piston 2. A first air inlet pipe 6, an exhaust pipe 7 and a pressure gauge 8 are installed on the top of the air cavity 3. The first air inlet pipe 6 is equipped with an air intake check valve. The air chamber 3 can be inflated through the first air inlet pipe 6 to form a positive pressure in the air chamber 3. The exhaust pipe 7 is equipped with a first switch 10. The air chamber 3 can be exhausted by opening the first switch 10. The pressure gauge 8 detects the pressure in the air chamber 3. It also includes a flat pad 11, which is placed under the cylinder 1 to close the cylinder mouth. The sand storage chamber 4 is filled with fine sand. Under the action of the positive pressure above the piston 2, the fine sand is compacted. A water and gas common pipe 12 and a second air inlet pipe 13 are installed on the side wall of the sand storage chamber 4. A second switch 14 is installed on the water and gas common pipe 12. The water and gas common pipe 1 2 is used for water intake and exhaust, and a third switch 15 is installed on the second air intake pipe 13. The second air intake pipe 13 is used to let in hot air to dry the fine sand; a drainage groove 16 is opened on the lower end surface of the cylinder 1, and a pipe sleeve 17 is coaxially sleeved on the lower end of the outer wall of the cylinder 1. The pipe sleeve 17 fits the outer wall of the cylinder 1 and can move up and down. When the pipe sleeve 17 moves down to the lower end and is flush with the lower end of the cylinder 1, the drainage groove 16 is closed. When the pipe sleeve 17 moves up, the drainage groove 16 is opened, and the water in the sand storage chamber 4 can be quickly discharged from the drainage groove 16; a drain trough 16 is installed at the axis of the cylinder 1. The rotating shaft 18 has an upper end which passes through the cylinder 1 and is connected to a drive motor 19. The lower end of the rotating shaft 18 penetrates the piston 2 and is provided with a plurality of radial sand scraping plates 20. The bottom surface of the sand scraping plates 20 is flush with the lower end surface of the cylinder 1. The rotating shaft 18 is rotated in conjunction with the upper end of the cylinder 1. The rotating shaft 18 can rotate relative to the piston 2, and the piston 2 can move up and down along the rotating shaft 18. Sealing rings are installed between the rotating shaft 18 and the piston 2, and between the rotating shaft 18 and the cylinder 1. The drive motor 19 drives the sand scraping plates 20 to rotate through the rotating shaft 18, so that the sand particles penetrate into the cracks in the road surface.

[0039] The pad 11 is composed of a first pad 21 and a second pad 22 stacked together. The first pad 21 has a thickness of 5 to 10 mm and is made of metal plate. It has sufficient rigidity to provide support when compacting fine sand. The second pad 22 is overlapped and stacked on top of the first pad 21. The second pad 22 has a thickness of 0.1 to 0.3 mm and is made of thin metal plate, thin cardboard or thin plastic plate. When the pad 11 is pulled out from the bottom of the cylinder 1, the first pad 21 is pulled out first. When the first pad 21 is pulled out, the second pad 22 is kept closed to the cylinder mouth. After the first pad 21 is pulled out, the second pad 22 is flattened on the ground, and then the second pad 22 is pulled out. Since the second pad 22 is thin, no sand will leak when it is pulled out.

[0040] The pipe sleeve 17 is provided with a vertical avoidance groove 23 , through which the water-gas common pipe 12 and the second air inlet pipe 13 pass, without affecting the up-and-down movement of the pipe sleeve 17 .

[0041] The cross section of the sand scraper 20 is wedge-shaped, with the tip of the wedge facing the direction of rotation, which can reduce the resistance of the sand scraper 20 when rotating.

[0042] A sand filter 24 is installed at the lower end of the inner wall of the cylinder 1 to prevent fine sand from entering the water and gas common pipe 12, the second air inlet pipe 13 and the drainage trough 16.

[0043] The outer wall of the cylinder 1 is provided with a vibration motor 25, which assists in compacting the fine sand by vibration.

[0044] The detection method using the depth detection device of the above structure includes the following steps:

[0045] Step 1: Dry the fine sand to be tested with hot air;

[0046] Step 2: Turn the mouth of the cylinder 1 upward, fill the dried fine sand into the sand storage chamber 4 of the cylinder 1, and cover the mouth of the cylinder with the second pad 22 and the first pad 21 in sequence. Then, turn the cylinder 1 over and place it stably on the detection point. The upper end of the cylinder 1 is pressed by counterweight or pressure to prevent it from lifting. At this time, the inner end of the limit bolt 5 extends below the piston 2 to limit the piston 2. When the piston 2 contacts the limit bolt 5, the volume of the air cavity 3 is V0, and V0 is a constant value. Inflate the air cavity 3 through the first air inlet pipe 6 until the air cavity 3 reaches the set positive pressure value P0 and then stop inflating.

[0047] The limiting bolt 5 is screwed outward to release the limit on the piston 2. The air pressure in the air chamber 3 acts on the fine sand in the sand storage chamber 4 through the piston 2. Then the vibration motor 25 is started. The fine sand in the sand storage chamber 4 is vibrated and compacted under the action of vibration and the pressure of the piston 2. When the piston 2 descends during the compaction process of the fine sand, the air pressure in the air chamber 3 decreases. The vibration continues until the reading of the pressure gauge 8 stabilizes for more than 1 minute, then stops. The reading P1 of the pressure gauge 8 at this time is recorded.

[0048] Step 3: Slowly pull out the first pad 21, while keeping the second pad 22 in contact with the tube mouth. After the first pad 21 is pulled out, the second pad 22 is in contact with the ground. Then slowly pull out the second pad 22, so that the tube body 1 is directly placed on the ground at the detection point, and the fine sand is in direct contact with the ground.

[0049] Step 4: Connect the water-gas common pipe 12 to the pressurized water source, open the second switch 14 to inject water into the sand storage chamber 4, and the water seeps into the road surface. At the same time, the drive motor 19 is started to drive the sand scraper 20 to rotate. The fine sand fills the road surface gaps under the action of the sand scraper 20 and seeps into all parts of the road surface gaps with the seepage water flow, thereby ensuring that the fine sand fills the road surface gaps. As the fine sand seeps down, the piston 2 moves downward synchronously under the action of the pressure in the air cavity 3, and the air pressure in the air cavity 3 decreases. The water injection and sand scraping continue until the reading of the barometer 8 is stable for more than 1 minute.

[0050] Step 5: Stop water injection, turn off the motor, pull up the pipe sleeve 17, open the drainage groove 16, and drain the free water in the sand storage chamber 4 from the drainage groove 16. Then, connect the second air inlet pipe 13 to the hot air source, turn on the third switch 15 and the second switch 14, and let hot air into the sand storage chamber 4 to dry the fine sand. The hot air is discharged from the water and gas common pipe 12. The drying degree of the fine sand is determined by detecting the humidity of the discharged hot air. When the drying degree of the fine sand reaches the same as that in step 1, the drying is stopped.

[0051] Step 6: Start the vibration motor 25 and vibrate until the reading of the barometer 8 is stable for more than one minute, then stop and record the reading P2 of the barometer 8 at this time;

[0052] Step 7: Calculate the structural depth TD within the air cavity 3 according to the gas equation PV=nRT;

[0053] Where P is pressure;

[0054] V is volume;

[0055] n is the molar mass. The gas in the gas cavity 3 is constant, so n is a constant at this time;

[0056] R is a constant;

[0057] T is the absolute temperature, which is also a constant at this time;

[0058] Therefore, P0V0=P1V1=P2V2=constant;

[0059] Where V1 is the volume of air cavity 3 when recording P1;

[0060] V2 is the volume of air cavity 3 when recording P2;

[0061] From this formula, we can calculate V1=P0V0 / P1 and V2=P0V0 / P2, and calculate the volume difference V 差 =V2-V1, since the diameter of the cylinder 1 is the same at the top and bottom, the volume of the fine sand in the sand storage chamber 4 is reduced, that is, the volume of the fine sand that extends into the gap in the road surface is V 沙 = V 差 =V2-V1;

[0062] Then the structural depth of the road surface TD=V沙 / S=(V2-V1) / S=(P0V0 / P2-P0V0 / P1) / S, where S is the inner diameter cross-sectional area of ​​cylinder 1.

[0063] Before step 2, the road surface at the monitoring point is washed with a high-pressure water gun to clean out impurities in the cracks in the road surface, and then blown dry with hot air. Keeping the road surface dry can increase the amount and speed of water penetrating into the road surface during testing, thereby better carrying fine sand to the corners of the cracks.

[0064] In step 2, P0 is 1.3 to 1.5 atmospheres.

[0065] The present invention improves the sand spreading method and has no fundamental defects. The fine sand is carried by water flow into the gaps in the road surface. Compared with the traditional sand scraping method, the road surface gaps can be filled more fully. The reduction in fine sand in the sand storage chamber 4 is used as the volume of fine sand that has seeped into the gaps in the road surface. Compared with the traditional method of measuring the amount of sand in advance and leveling it by scraping, the subjective judgment of the leveling state is eliminated. Therefore, the sand measurement method of the present invention is more reasonable. The amount of sand reduced in the sand storage chamber 4 is calculated by the change in air pressure, which can accurately measure tiny volume changes. In addition, the cylinder 1 limits the spreading area of ​​the fine sand to a constant value. The present invention can obtain more reasonable and accurate sand quantity and area, and thus obtain more accurate detection results.

Claims

1. A road surface structure depth detection device, comprising a cylinder (1) with an open lower end and a closed upper end, characterized in that: A piston (2) is installed in the cylinder (1), a closed air cavity (3) is formed above the piston (2), a sand storage chamber (4) is located below the piston (2), a radial limit bolt (5) is installed on the side wall of the cylinder (1), the inner end of the limit bolt (5) extends to the bottom of the piston (2) and can limit the initial position of the piston (2), a first air inlet pipe (6), an exhaust pipe (7) and a pressure gauge (8) are installed on the top of the air cavity (3), an air inlet check valve is installed on the first air inlet pipe (6), and a first switch (10) is installed on the exhaust pipe (7); a flat backing plate (11) is also included, the backing plate (11) is placed below the cylinder (1) to close the cylinder mouth, the sand storage chamber (4) is filled with fine sand, a water and gas common pipe (12) and a second air inlet pipe (13) are installed on the side wall of the sand storage chamber (4), and the water and gas common pipe (12) and the second air inlet pipe (13) are installed. The tube (12) is provided with a second switch (14), and the second air inlet pipe (13) is provided with a third switch (15); a drainage groove (16) is provided on the lower end surface of the cylinder (1), and a pipe sleeve (17) is coaxially sleeved on the lower end of the outer wall of the cylinder (1), and the pipe sleeve (17) is fitted with the outer wall of the cylinder (1) and can move up and down. When the pipe sleeve (17) moves down to the lower end and is flush with the lower end of the cylinder (1), the drainage groove (16) is closed, and when the pipe sleeve (17) moves up, the drainage groove (16) is opened; a rotating shaft (18) is provided at the axis of the cylinder (1), the upper end of the rotating shaft (18) passes through the cylinder (1) and is connected to a driving motor (19), the lower end of the rotating shaft (18) passes through the piston (2) and is provided with a plurality of radial sand scraping plates (20), and the bottom surface of the sand scraping plate (20) is flush with the lower end surface of the cylinder (1).

2. A road surface structure depth detection device according to claim 1, characterized in that: The pad (11) is formed by stacking a first pad (21) and a second pad (22), wherein the thickness of the first pad (21) is 5 to 10 mm, and the second pad (22) is overlapped and stacked on the first pad (21), and the thickness of the second pad (22) is 0.1 to 0.3 mm.

3. The road surface structure depth detection device according to claim 1, characterized in that: The pipe sleeve (17) is provided with a vertical avoidance groove (23), and the water-gas common pipe (12) and the second air inlet pipe (13) pass through the avoidance groove (23) without affecting the up and down movement of the pipe sleeve (17).

4. The road surface structure depth detection device according to claim 1, characterized in that: The cross section of the sand scraping plate (20) is wedge-shaped, with the tip of the wedge facing the direction of rotation.

5. The road surface structure depth detection device according to claim 1, characterized in that: The lower end of the inner wall of the cylinder (1) is provided with a sand filter (24).

6. The road surface structure depth detection device according to claim 1, characterized in that: The outer wall of the cylinder (1) is equipped with a vibration motor (25).

7. A detection method for a road surface structure depth detection device, characterized in that: The detection device is the detection device according to any one of claims 1 to 6, comprising the following steps: Step 1: Dry the fine sand to be tested with hot air; Step 2: Turn the mouth of the cylinder (1) upward, fill the dried fine sand into the sand storage chamber (4) of the cylinder (1), and cover the mouth of the cylinder with the second pad (22) and the first pad (21) in sequence, then turn the cylinder (1) over and place it steadily at the detection point, at this time, the inner end of the limit bolt (5) extends below the piston (2) to limit the piston (2), and when the piston (2) contacts the limit bolt (5), the volume of the air cavity (3) is V0, and V0 is a constant value. The air is inflated into the air cavity (3) through the first air inlet pipe (6), and the inflation is stopped after the air cavity (3) reaches the set positive pressure value P0; The limiting bolt (5) is screwed outward to release the limit on the piston (2), and then the vibration motor (25) is started. The vibration continues until the reading of the pressure gauge (8) is stable for more than 1 minute and then stops. The reading P1 of the pressure gauge (8) at this time is recorded; Step 3, slowly pulling out the first pad (21), after pulling out the first pad (21), the second pad (22) is placed in contact with the ground, and then slowly pulling out the second pad (22); Step 4: Connect the water and air common pipe (12) to the pressure water source, open the second switch (14) to inject water into the sand storage chamber (4), and the water seeps down to the road surface. At the same time, start the drive motor (19) to drive the sand scraper (20) to rotate. The water injection and sand scraping continue until the reading of the pressure gauge (8) is stable for more than 1 minute. Step 5: stop water injection, turn off the motor, pull up the pipe sleeve (17), open the drainage groove (16), and drain the free water in the sand storage chamber (4) from the drainage groove (16). Then, connect the second air inlet pipe (13) to the hot air source, turn on the third switch (15) and the second switch (14), and let hot air into the sand storage chamber (4) to dry the fine sand. The hot air is discharged from the water and air common pipe (12). The drying degree of the fine sand is determined by detecting the humidity of the discharged hot air. When the drying degree of the fine sand reaches the same as that in step 1, the drying is stopped. Step 6: Start the vibration motor (25) and vibrate until the reading of the pressure gauge (8) is stable for more than one minute, then stop and record the reading P2 of the pressure gauge (8) at this time; Step 7: Calculate the structural depth TD, for the air cavity (3), according to the gas equation PV=nRT; Where P is pressure; V is volume; n is the molar mass. The gas in the cavity (3) is constant, so n is a constant at this time. R is a constant; T is the absolute temperature, which is also a constant at this time; Therefore, P0V0=P1V1=P2V2=constant; Where V1 is the volume of the air cavity (3) when recording P1; V2 is the volume of the air cavity (3) when P2 is recorded; From this formula, we can calculate V1=P0V0 / P1 and V2=P0V0 / P2, and calculate the volume difference V 差 =V2-V1, since the diameter of the cylinder (1) is the same at the top and bottom, the volume of the fine sand in the sand storage chamber (4) is reduced, that is, the volume of the fine sand that penetrates into the cracks in the road surface is V 沙 = V 差 =V2-V1; Then the structural depth of the road surface TD=V 沙 / S=(V2-V1) / S=(P0V0 / P2-P0V0 / P1) / S, where S is the inner diameter cross-sectional area of ​​the cylinder (1).

8. The detection method of a road surface structure depth detection device according to claim 7, characterized in that: Before step 2, the road surface at the monitoring point is washed with a high-pressure water gun and then blown dry with hot air.

9. The detection method of a road surface structure depth detection device according to claim 7, wherein in step 2, P0 is 1.3 to 1.5 atmospheres.

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