A device and method for measuring the water permeability coefficient of a road bridge surface

Abstract

The present application relates to a new material road bridge water seepage detection technical field, specifically to a kind of road bridge surface water seepage coefficient measuring device and measuring method, measuring device includes base, and be provided with inner measuring cylinder and outer measuring cylinder on base, annular cavity is formed between outer measuring cylinder and inner measuring cylinder, and through-hole is provided on the circumferential wall of inner measuring cylinder, and through-hole is connected with inner measuring cylinder and annular cavity;Inner piston is inserted in inner measuring cylinder, and inner piston and inner measuring cylinder form piston cooperation, and inner measuring cylinder is divided into upper column cavity and lower column cavity, and inner two-way pressure difference valve is provided on inner piston, and inner two-way pressure difference valve is connected with upper column cavity and lower column cavity when opening;Outer piston is inserted in annular cavity, and outer piston is simultaneously piston cooperation with inner measuring cylinder and outer measuring cylinder, and annular cavity is divided into upper ring cavity and lower ring cavity, and outer two-way pressure difference valve is provided on outer piston, and outer two-way pressure difference valve is connected with upper ring cavity and lower ring cavity when opening;To ensure that liquid level in inner measuring cylinder and liquid level in annular cavity always keep consistent, guarantee the accuracy of detection result.

Description

Technical Field

[0001] This invention relates to the field of new material road and bridge water seepage detection technology, and in particular to a device and method for measuring the surface water seepage coefficient of road and bridges. Background Technology

[0002] The surface materials of roads and bridges must meet core requirements such as load-bearing stability, water permeability, environmental adaptability, and durability. With the iteration of materials technology, a batch of new materials that combine high performance and functional adaptability are gradually replacing traditional materials and are widely used in various bridge engineering scenarios.

[0003] Special asphalt-based composite materials are a new type of material that is an improvement and upgrade of traditional asphalt materials. By adjusting the composition ratio or introducing special additives, the fluidity, density and durability of the surface layer are enhanced, making them suitable for special construction and use scenarios such as long-span bridges.

[0004] The permeability coefficient, as a core technical indicator for evaluating the drainage performance of special asphalt-based composite road and bridge surfaces, directly relates to two key engineering attributes: first, the traffic safety guarantee capability of special asphalt-based composite pavements in rainy weather, as surface water films formed due to poor permeability can easily lead to vehicle skidding; second, the water damage resistance capability of the special asphalt-based composite pavement structure, as long-term retention of water will gradually erode the interface between the surface layer and the base layer of the special asphalt-based composite pavement, exacerbating the generation and development of defects such as cracks and loosening. Therefore, accurately measuring the permeability coefficient of special asphalt-based composite road and bridge surfaces is an important basis for quality control during the construction and maintenance decisions during the operational phase of special asphalt-based composite road construction.

[0005] When determining the permeability coefficient of special asphalt-based composite road and bridge surfaces, a relevant measuring device is required. For example, Chinese patent CN104849196B discloses a device for determining the permeability coefficient of asphalt pavement. This device includes a base with a hollow cavity, a measuring cylinder upright on the top of the base, and a quick-opening valve at the bottom of the measuring cylinder. The measuring cylinder communicates with the hollow cavity through the open quick-opening valve. During testing, the base is first placed on the ground, then the measuring cylinder is filled with water. The quick-opening valve is then opened, and the water flows sequentially through the measuring cylinder and the quick-opening valve into the hollow cavity, then seeps into the road surface. The seepage time and volume are recorded simultaneously, allowing the calculation of the pavement permeability coefficient. For example, two nested graduated cylinders are used, with the inner cylinder forming a central circular seepage area and the two cylinders forming an outer ring-shaped seepage area. In use, water is added to both cylinders, and the outer ring-shaped seepage area forms a water seal-like effect between the base and the road surface, ensuring the integrity of the central circular seepage area and preventing leakage, thereby ensuring the accuracy of the measurement results.

[0006] However, when the initial liquid levels in the two measuring cylinders are inconsistent, it directly affects the seepage rate of the central circular seepage area and the outer annular seepage area, causing the seepage ranges of the two types of areas to overlap and interfere with the capture of the true seepage state of the special asphalt-based composite road and bridge surface, thereby reducing the accuracy of the measurement results. At the same time, in the operation of using an air vent valve to remove air from the hollow cavity, the traditional method of judging whether the air has been completely removed by observing whether water comes out of the air vent valve does not fully take into account the seepage characteristics of the special asphalt-based composite surface, which can easily lead to the ineffective loss of water resources, and may also affect the stability of the seepage process on the surface of the special asphalt-based composite material due to incomplete air venting, further interfering with the reliability of the test results. Summary of the Invention

[0007] Therefore, it is necessary to provide a device and method for measuring the permeability coefficient of road and bridge surfaces, addressing the problems of poor accuracy and water waste in the current process of measuring the permeability coefficient of special asphalt-based composite materials.

[0008] The above objectives are achieved through the following technical solutions:

[0009] A device for measuring the surface permeability coefficient of a road or bridge includes a base placed on the surface of the road or bridge, forming an inner cavity and an outer cavity between the base and the surface, with the outer cavity surrounding the inner cavity. The bottom of the base has an inner seal and an outer seal, the inner seal sealing the inner cavity and the outer seal sealing the outer cavity. The top of the base has an inner measuring cylinder and an outer measuring cylinder, the outer measuring cylinder surrounding the inner measuring cylinder, forming an annular cavity between them. Both the inner and outer measuring cylinders have a switch valve at their bottoms. The inner measuring cylinder is connected to the inner cavity via an open switch valve, and the annular cavity is connected to the outer cavity via an open switch valve. A through hole is provided on the peripheral wall of the inner measuring cylinder, connecting the inner measuring cylinder and... The annular cavity consists of an inner piston inserted into an inner measuring cylinder, forming a piston-like fit with the inner measuring cylinder and dividing the inner measuring cylinder into an upper and lower cylindrical cavity. An internal two-way differential pressure valve is installed on the inner piston; when the valve is open, it connects the upper and lower cylindrical cavity, maintaining a dynamic equilibrium between the weight and sliding friction of the inner piston. An outer piston is also inserted into the annular cavity, forming a piston-like fit with both the inner and outer measuring cylinders and dividing the annular cavity into an upper and lower ring cavity. An external two-way differential pressure valve is installed on the outer piston; when open, it connects the upper and lower ring cavity, maintaining a dynamic equilibrium between the weight and sliding friction of the outer piston. Both the inner and outer measuring cylinders are made of transparent material, and graduation lines are provided on the circumferential wall of the inner measuring cylinder.

[0010] Furthermore, an inner support rod is provided at the top of the inner piston, extending in a direction parallel to the axis of the inner measuring cylinder, and an inner hand ring is provided at the top of the inner support rod; an outer support rod is provided at the top of the outer piston, extending in a direction parallel to the axis of the outer measuring cylinder, and an outer hand ring is provided at the top of the outer support rod.

[0011] Furthermore, the inner and outer support rods are arranged side by side; the inner and outer wristbands are at the same height.

[0012] Furthermore, there are an even number of inner support rods, which are divided into two groups. The two groups are arranged opposite each other along the circumference of the inner piston, and the inner support rods in the same group are arranged along the same radial direction of the inner piston.

[0013] Furthermore, there are an even number of outer support rods, which are divided into two groups. The two groups are arranged opposite each other along the circumference of the outer piston, and the outer support rods in the same group are arranged along the same radial direction of the outer piston.

[0014] Furthermore, the bottom of the outer measuring cylinder is equipped with multiple switching valves, which are arranged circumferentially, and the annular cavity can be connected to the outer cavity simultaneously through multiple open switching valves.

[0015] Furthermore, there are multiple external bidirectional differential pressure valves, arranged circumferentially.

[0016] Furthermore, there are multiple through holes, arranged circumferentially.

[0017] Furthermore, a level is installed on the base.

[0018] This invention also provides a method for determining the surface permeability coefficient of roads and bridges, employing a device for determining the surface permeability coefficient of roads and bridges. The method for determining the surface permeability coefficient of roads and bridges includes the following steps:

[0019] S1. Clean the test area on the surface of the road and bridge;

[0020] S2. Place the road and bridge surface permeability coefficient measuring device in the test area, with an inner cavity and an outer cavity formed between the base and the road and bridge surface.

[0021] S3. Add water into the inner measuring cylinder and / or the annular cavity. Driven by the water flow, the inner piston moves to the bottom of the inner measuring cylinder and the outer piston moves to the bottom of the annular cavity. With the through hole connected, the liquid levels in the inner measuring cylinder and the annular cavity are the same.

[0022] S4. Synchronously drive the inner piston and outer piston to move upward, forming a pressure difference between the upper and lower cylinder chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve opens, and the water in the upper cylinder chamber enters the lower cylinder chamber; at the same time, a pressure difference is formed between the upper and lower ring chambers. Under the action of the pressure difference, the outer bidirectional pressure difference valve opens, and the water in the upper ring chamber enters the lower ring chamber.

[0023] S5. Open the switch valve, and the water in the lower column chamber enters the inner cavity, and squeezes the air in the inner cavity to the top of the liquid surface in the lower column chamber. The water in the lower ring chamber enters the outer cavity, and squeezes the air in the outer cavity to the top of the liquid surface in the lower ring chamber.

[0024] S6. Close the switch valve;

[0025] S7. Simultaneously, the inner and outer pistons move downwards to contact the liquid surface, creating a pressure difference between the upper and lower column chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve opens, allowing air above the liquid surface in the lower column chamber to enter the upper column chamber. At the same time, a pressure difference is created between the upper and lower ring chambers. Under the action of the pressure difference, the outer bidirectional pressure difference valve opens, allowing air above the liquid surface in the lower ring chamber to enter the upper ring chamber.

[0026] S8. Simultaneously drive the inner piston and outer piston to move upward, forming a pressure difference between the upper and lower cylinder chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve opens, and the water in the upper cylinder chamber enters the lower cylinder chamber until the liquid level in the lower cylinder chamber reaches the first preset scale V1, maintaining the position of the inner piston and outer piston; at the same time, a pressure difference is formed between the upper and lower ring chambers. Under the action of the pressure difference, the outer bidirectional pressure difference valve opens, and the water in the upper ring chamber enters the lower ring chamber.

[0027] S9. Simultaneously release the inner and outer pistons, open the switch valve, and record the time t it takes for the liquid level in the column cavity to reach the second preset scale V2.

[0028] S10. Calculate the permeability coefficient Cw = (V2 - V1) / t;

[0029] S11. Change the test area and repeat steps S1-S10.

[0030] The beneficial effects of this invention are:

[0031] This invention relates to a device and method for measuring the surface permeability coefficient of roads and bridges. By configuring an inner piston, an outer piston, an inner bidirectional differential pressure valve mounted on the inner piston, and an outer bidirectional differential pressure valve mounted on the outer piston, the device utilizes the characteristic that the inner and outer bidirectional differential pressure valves can open when a set pressure difference is achieved. The movement of the inner and outer pistons allows for the discharge of air from the inner and outer cavities, avoiding the need for venting valves and thus preventing water waste. Furthermore, a through-hole is provided, ensuring that the liquid level in the upper cylinder cavity and the upper annular cavity remains consistent. Simultaneously, the dynamic equilibrium between the gravity and sliding friction of both the inner and outer pistons ensures that the seepage rate of the central circular seepage area and the outer annular seepage area is the same, preventing the outer annular seepage area from intersecting with the central circular seepage area, thereby ensuring the accuracy of the measurement results. Attached Figure Description

[0032] Figure 1 This is a three-dimensional structural schematic diagram of the road and bridge surface permeability coefficient measuring device provided in an embodiment of the present invention;

[0033] Figure 2 This is a front view schematic diagram of the road and bridge surface permeability coefficient measuring device provided in an embodiment of the present invention;

[0034] Figure 3 This is a side view of the road and bridge surface permeability coefficient measuring device provided in an embodiment of the present invention;

[0035] Figure 4 for Figure 3 Sectional view along the AA direction;

[0036] Figure 5 for Figure 4 A magnified schematic diagram of the structure at point Y in the middle;

[0037] Figure 6 This is a three-dimensional cross-sectional view of the road and bridge surface permeability coefficient measuring device provided in an embodiment of the present invention;

[0038] Figure 7 for Figure 6 A magnified schematic diagram of the structure at point Z in the middle;

[0039] Figure 8 This is an exploded view of the components of the road and bridge surface permeability coefficient measuring device provided in an embodiment of the present invention.

[0040] in:

[0041] 1. Base; 101. Upper base plate; 102. Lower base plate; 1021. Inner groove; 1022. Outer groove; 103. Bolt and nut assembly; 104. Inner seal; 105. Outer seal;

[0042] 2. Inner measuring cylinder; 201. Through hole;

[0043] 3. External measuring cylinder;

[0044] 4. Switch valve; 401. Connecting pipe;

[0045] 5. Inner piston; 501. Inner support rod; 502. Inner hand ring;

[0046] 6. External piston; 601. External support rod; 602. External hand ring;

[0047] 7. Internal bidirectional differential pressure valve;

[0048] 8. External two-way differential pressure valve;

[0049] 9. First sealing element; 901. First connecting hole;

[0050] 10. Second sealing element; 1001. Second connecting hole. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0052] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage," unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0053] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] Common special asphalt-based composite materials include castable asphalt mixtures, high-elasticity ultra-thin overlay materials, and high-strength castable asphalt concrete. Among them, castable asphalt mixtures have excellent fluidity after high-temperature mixing. Asphalt concrete materials are laid by casting and do not require compaction. Their core advantages are extremely low porosity and strong integrity. They also have corrosion resistance, wear resistance, and high viscosity and toughness. They can adapt well to the structural characteristics of orthotropic steel bridge decks and resist the complex environmental erosion of long-span sea bridges.

[0055] High-elasticity ultra-thin overlay material is based on ordinary SBS modified asphalt, and is a high-viscoelastic mixture formed by dry addition of special modifying additives and crack-resistant fibers, with a paving thickness of only 1.5-2.5cm. It has wide temperature adaptability, resisting rutting at high temperatures and cracking at low temperatures, while also possessing anti-skid and low-noise properties, exhibiting significantly superior durability compared to traditional ultra-thin overlay materials. It can be constructed using traditional paving and compaction processes, making it highly adaptable and suitable for functional overlays of wearing courses on highways, urban roads, tunnels, and viaducts, especially suitable for upgrading and maintaining old road surfaces.

[0056] High-strength castable asphalt concrete combines the advantages of resin-based concrete and castable asphalt concrete. It is made by mixing flexible epoxy resin binder, aggregates, mineral powder, etc. at room temperature, and relies on its own fluidity to be laid and shaped without compaction. It has high density and low porosity, and combines high strength with excellent high and low temperature performance and waterproof performance. It is suitable for the construction or maintenance of bridges and roads such as steel bridge decks, concrete bridge decks, and airport runways, and can effectively improve the load-bearing capacity and service life of the surface layer.

[0057] In existing permeability coefficient measuring devices with two graduated cylinders, the liquid level in the cylinders is a key factor determining the water pressure when measuring the permeability coefficient of special asphalt-based composite road and bridge surfaces. A higher liquid level results in greater hydrostatic pressure on the test area, leading to faster water permeation under pressure difference. When the liquid levels in the two cylinders are inconsistent, a difference in water pressure arises between the central circular area and the outer annular area. This pressure difference directly causes the permeation rate in both areas to deviate from its true characteristics: the test area corresponding to the cylinder with the higher liquid level will have a higher permeation rate due to the additional pressure, while the area corresponding to the cylinder with the lower liquid level will have a lower permeation rate due to insufficient pressure. More importantly, this velocity deviation caused by the difference in liquid level is not independent. The two test areas are spatially adjacent, and during the permeation process, water may form mutually interfering seepage fields within the pavement, further distorting their true permeation patterns. Ultimately, the permeability coefficient calculated based on this interfered permeation rate will fail to accurately reflect the actual drainage performance of the pavement, rendering the measurement data unreliable.

[0058] Based on this, the present invention provides a device for measuring the permeability coefficient of road and bridge surfaces, which is particularly suitable for measuring the permeability coefficient of special asphalt-based composite road and bridge surfaces. Of course, it is also suitable for measuring the permeability coefficient of other new material pavements.

[0059] Specifically, refer to Figures 1 to 8In the road and bridge surface permeability coefficient measuring device provided in this embodiment of the invention, it is configured to include a base 1, the base 1 having an upper base plate 101, the upper base plate 101 being horizontally arranged, and a lower base plate 102 being coaxially and spaced apart below the upper base plate 101, the lower base plate 102 being horizontally arranged and connected to the upper base plate 101 by a bolt and nut assembly 103; the bottom of the lower base plate 102 has an inner groove 1021, the inner groove 1021 being cylindrical in shape and coaxial with the lower base plate 102, when the base 1 is placed... When placed on the surface of a special asphalt-based composite road bridge, the inner groove 1021 and the surface of the special asphalt-based composite road bridge form an inner cavity; the bottom of the lower base plate 102 is also provided with an outer groove 1022, the outer groove 1022 is in the shape of a ring, and is coaxially arranged with the lower base plate 102, and is sleeved on the outside of the inner groove 1021. When the base 1 is placed on the surface of the special asphalt-based composite road bridge, the outer groove 1022 and the surface of the special asphalt-based composite road bridge form an outer cavity.

[0060] An inner sealing element 104 is inserted into the bottom of the lower base plate 102. The inner sealing element 104 has a ring-shaped structure and is coaxially arranged with the lower base plate 102, and is fitted around the outer periphery of the inner groove 1021. The inner sealing element 104 can be made of rubber material. When the base 1 is placed on the surface of the special asphalt-based composite road bridge, the inner sealing element 104 undergoes elastic deformation, which facilitates sealing the inner cavity. An outer sealing element 105 is also inserted into the bottom of the lower base plate 102. The outer sealing element 105 has a ring-shaped structure and is coaxially arranged with the lower base plate 102, and is fitted around the outer periphery of the outer groove 1022. The outer sealing element 105 can be made of rubber material. When the base 1 is placed on the surface of the special asphalt-based composite road bridge, the outer sealing element 105 undergoes elastic deformation, which facilitates sealing the outer cavity.

[0061] An inner measuring cylinder 2 is coaxially mounted on the top of the upper base plate 101, with its top end open. An outer measuring cylinder 3 is also coaxially mounted on the top of the upper base plate 101, with its top end open, and is fitted around the outer periphery of the inner measuring cylinder 2, forming an annular cavity between them. Two connecting pipes 401 are vertically positioned between the upper base plate 101 and the lower base plate 102. One connecting pipe 401 is coaxially mounted with the inner measuring cylinder 2 and connects the inner measuring cylinder 2 to the inner groove 1021. The other connecting pipe 401 is located between the inner measuring cylinder 2 and the outer measuring cylinder 3 and connects the annular cavity to the outer groove 1022. A switch valve 4 is inserted into each connecting pipe 401. The inner measuring cylinder 2 is connected to the inner cavity through the connecting pipe 401 and the open switch valve 4, and the annular cavity is connected to the outer cavity through the connecting pipe 401 and the open switch valve 4.

[0062] To ensure a tight seal between the inner measuring cylinder 2 and the connecting pipe 401, a first sealing element 9 is provided at the bottom of the inner measuring cylinder 2. The first sealing element 9 has an annular structure and a first connecting hole 901 in the center, and can be made of rubber. The first sealing element 9 is fitted onto the connecting pipe 401 through the first connecting hole 901. To ensure a tight seal between the outer measuring cylinder 3 and the connecting pipe 401, a second sealing element 10 is provided at the bottom of the annular cavity. The second sealing element 10 has an annular structure and a second connecting hole 1001. The second sealing element 10 is fitted onto the connecting pipe 401 through the second connecting hole 1001, and can be made of rubber. A through hole 201 is provided on the peripheral sidewall of the inner measuring cylinder 2, which connects the inner measuring cylinder 2 and the annular cavity, facilitating the exchange of liquids between the inner measuring cylinder 2 and the annular cavity, thereby helping to maintain a consistent liquid level.

[0063] An inner piston 5, a disc-shaped structure, is inserted inside the inner measuring cylinder 2. The inner piston 5 is horizontally positioned and forms a piston-like connection with the inner measuring cylinder 2, dividing it into an upper and lower column chamber. An internal bidirectional differential pressure valve 7 is coaxially mounted on the inner piston 5. When the pressure in the upper column chamber is greater than the pressure in the lower column chamber, and the pressure difference reaches the set differential pressure of the internal bidirectional differential pressure valve 7, the valve opens downwards, connecting the upper and lower column chambers. When the pressure in the upper column chamber is less than the pressure in the lower column chamber, and the pressure difference reaches the set differential pressure of the valve 7, the valve opens upwards, connecting the upper and lower column chambers. The through-hole 201 is always located above the inner piston 5. The gravity and sliding friction of the inner piston 5 are in a dynamic equilibrium, ensuring that when the inner piston 5 slides within the inner measuring cylinder 2, it does not generate a force that pushes the water in the lower column chamber downwards, thus avoiding affecting the permeation rate of the water in the lower column chamber driven by the pressure difference.

[0064] Specifically, the weight of the inner piston 5 and the sliding friction can be dynamically balanced by adjusting the counterweight of the inner piston 5 or by selecting a seal with a low coefficient of friction, so as to ensure that the inner piston 5 can descend synchronously with the liquid surface.

[0065] An outer piston 6 is inserted into the annular cavity. The outer piston 6 has an annular structure and is horizontally positioned. It forms a piston-like engagement with both the inner measuring cylinder 2 and the outer measuring cylinder 3. The outer piston 6 divides the annular cavity into an upper annular cavity and a lower annular cavity. An external bidirectional differential pressure valve 8 is installed on the outer piston 6. When the pressure in the upper annular cavity is greater than the pressure in the lower annular cavity, and the pressure difference reaches the set differential pressure of the external bidirectional differential pressure valve 8, the external bidirectional differential pressure valve 8 opens downward, connecting the upper and lower annular cavities. When the pressure in the upper annular cavity is less than the pressure in the lower annular cavity, and the pressure difference reaches the set differential pressure of the external bidirectional differential pressure valve 8, the external bidirectional differential pressure valve 8 opens upward, connecting the upper and lower annular cavities. The gravity and sliding friction of the outer piston 6 are in a dynamic equilibrium state, ensuring that when the outer piston 6 slides between the inner measuring cylinder 2 and the outer measuring cylinder 3, it will not generate a force that pushes the water in the lower annular cavity downward, thus avoiding affecting the permeation rate of water driven by the pressure difference.

[0066] Specifically, the weight of the outer piston 6 can be adjusted or a seal with a low coefficient of friction can be selected to ensure that the weight of the outer piston 6 and the sliding friction are in a dynamic balance, so as to ensure that the outer piston 6 can descend synchronously with the liquid surface.

[0067] Both the inner measuring cylinder 2 and the outer measuring cylinder 3 are made of transparent materials, such as plastic. The inner measuring cylinder 2 has graduation lines on its peripheral sidewalls, which extend in a direction parallel to the axis of the inner measuring cylinder 2, making it easy to determine the amount of water added to the inner measuring cylinder 2 and the annular cavity.

[0068] To facilitate the sliding of the inner piston 5 inside the inner measuring cylinder 2, an inner support rod 501 is provided at the top of the inner piston 5. The inner support rod 501 extends in a direction parallel to the axis of the inner measuring cylinder 2, and its top end extends upward to the top of the inner measuring cylinder 2.

[0069] To facilitate the sliding of the outer piston 6 between the inner measuring cylinder 2 and the outer measuring cylinder 3, an outer support rod 601 is provided at the top of the outer piston 6. The outer support rod 601 extends in a direction parallel to the axis of the outer measuring cylinder 3, and its top end extends upward to the top of the outer measuring cylinder 3.

[0070] Initially, the switch valve 4 is in the closed state; the inner piston 5 can be located at the bottom of the inner measuring cylinder 2 or at any height within the inner measuring cylinder 2; the outer piston 6 can be located at the bottom of the annular cavity or at any height within the annular cavity.

[0071] Taking the example of the inner piston 5 being located at a certain height inside the inner measuring cylinder 2 and the outer piston 6 being located at a certain height inside the annular cavity; during use, first clean the test area on the surface of the special asphalt-based composite road bridge; then place the road bridge surface permeability coefficient measuring device at the test area, the inner groove 1021 and the surface of the special asphalt-based composite road bridge form an inner cavity, the outer groove 1022 and the surface of the special asphalt-based composite road bridge form an outer cavity, the inner seal 104 and the outer seal 105 simultaneously undergo elastic deformation, sealing the inner cavity and the outer cavity.

[0072] Then water is added to the inner measuring cylinder 2 and / or the annular cavity. Driven by the water flow, the inner piston 5 moves to the bottom of the inner measuring cylinder 2, and the outer piston 6 moves to the bottom of the annular cavity. With the through hole 201 connected, the liquid level in the inner measuring cylinder 2 and the annular cavity remains the same. Then, simultaneously pull the inner support rod 501 and the outer support rod 601 upwards. The inner piston 5 and the outer piston 6 move upwards synchronously, increasing the volume of the lower column cavity and decreasing the pressure, creating a pressure difference between the upper and lower ends of the inner bidirectional differential pressure valve 7. When the pressure difference reaches the set pressure difference of the inner bidirectional differential pressure valve 7, the inner bidirectional differential pressure valve 7 opens downwards, allowing water in the upper column cavity to enter the lower column cavity, squeezing the air in the lower column cavity and the air above the switch valve 4 in the connecting pipe 401 to the liquid surface. At the same time, the volume of the lower ring cavity increases and the pressure decreases, creating a pressure difference between the upper and lower ends of the outer bidirectional differential pressure valve 8. When the pressure difference reaches the set pressure difference of the outer bidirectional differential pressure valve 8, the outer bidirectional differential pressure valve 8 opens downwards, allowing water in the upper ring cavity to enter the lower ring cavity, squeezing the air in the lower ring cavity and the air above the switch valve 4 in the connecting pipe 401 to the liquid surface.

[0073] Then open valve 4. Water in the lower column chamber enters the inner cavity, pushing the air in the inner cavity to the top of the liquid surface in the lower column chamber. Water in the lower ring chamber enters the outer cavity, pushing the air in the outer cavity to the top of the liquid surface in the lower ring chamber. Then close valve 4. Then, simultaneously press down the inner support rod 501 and the outer support rod 601. The inner piston 5 moves downward synchronously until it contacts the liquid surface in the lower column cavity. During the movement of the inner piston 5, the volume of the lower column cavity decreases and the pressure increases, causing a pressure difference to appear between the upper and lower ends of the inner bidirectional differential pressure valve 7. When the pressure difference reaches the set pressure difference of the inner bidirectional differential pressure valve 7, the inner bidirectional differential pressure valve 7 opens upward, and the air above the liquid surface in the lower column cavity enters the upper column cavity and is then discharged to the outside from the upper column cavity. Simultaneously, the outer piston 6 moves downward synchronously until it contacts the liquid surface in the lower ring cavity. During the movement of the outer piston 6, the volume of the lower ring cavity decreases and the pressure increases, causing a pressure difference to appear between the upper and lower ends of the outer bidirectional differential pressure valve 8. When the pressure difference reaches the set pressure difference of the outer bidirectional differential pressure valve 8, the outer bidirectional differential pressure valve 8 opens upward, and the air above the liquid surface in the lower ring cavity enters the upper ring cavity and is then discharged to the outside from the upper ring cavity.

[0074] Then, simultaneously pull up the inner support rod 501 and the outer support rod 601. The inner piston 5 moves upward synchronously. During the movement of the inner piston 5, the volume of the lower column cavity increases and the pressure decreases, causing a pressure difference to appear between the upper and lower ends of the inner bidirectional differential pressure valve 7. When the pressure difference reaches the set pressure difference of the inner bidirectional differential pressure valve 7, the inner bidirectional differential pressure valve 7 opens downward, and the water in the upper column cavity enters the lower column cavity. The inner piston 5 moves until the liquid level in the lower column cavity reaches the first preset scale V1 and maintains the current position of the inner piston 5. The outer piston 6 moves upward synchronously. During the movement of the outer piston 6, the volume of the lower ring cavity increases and the pressure decreases, causing a pressure difference to appear between the upper and lower ends of the outer bidirectional differential pressure valve 8. When the pressure difference reaches the set pressure difference of the outer bidirectional differential pressure valve 8, the outer bidirectional differential pressure valve 8 opens downward, and the water in the upper ring cavity enters the lower ring cavity. The outer piston 6 moves until the liquid level in the lower ring cavity reaches the first preset scale V1, where V1 can be equal to 0, and maintains the current position of the outer piston 6.

[0075] Then, the inner support rod 501 and the outer support rod 601 are released simultaneously, and the switch valve 4 is opened at the same time. Under the action of water pressure, the water in the lower column cavity enters the inner cavity through the connecting pipe 401 and the switch valve 4, and then seeps into the surface of the special asphalt-based composite road bridge. The time t taken for the liquid level in the column cavity to reach the second preset scale V2 is recorded. The water in the lower ring cavity enters the outer cavity through the connecting pipe 401 and the switch valve 4, and then seeps into the surface of the special asphalt-based composite road bridge, achieving a water seal-like effect. Then, the permeability coefficient Cw = (V2 - V1) / t is calculated. Finally, the test area is changed, and the above process is repeated to obtain multiple permeability coefficients. The average value is then calculated, which is the permeability coefficient of the special asphalt-based composite road bridge surface.

[0076] Because the liquid levels in the inner measuring cylinder 2 and the outer measuring cylinder 3 remain consistent, the seepage rate of the central circular seepage area and the outer annular seepage area is the same, preventing the outer annular seepage area from intersecting with the central circular seepage area, thus ensuring the accuracy of the measurement results.

[0077] It should be noted that when the water seepage rate on the surface of special asphalt-based composite road and bridge surfaces is slow, the seepage coefficient can be calculated by measuring the seepage volume within 3 minutes.

[0078] In a further embodiment, to facilitate the sliding of the inner piston 5 within the inner measuring cylinder 2, an inner hand ring 502 is provided at the top of the inner support rod 501. The inner hand ring 502 is vertically positioned to facilitate pulling by hand.

[0079] Similarly, in order to facilitate the sliding of the outer piston 6 between the inner measuring cylinder 2 and the outer measuring cylinder 3, an outer hand ring 602 is provided at the top of the outer support rod 601. The outer hand ring 602 is set vertically to facilitate manual pulling.

[0080] In a further embodiment, to facilitate the simultaneous movement of the inner piston 5 and the outer piston 6, the inner support rod 501 and the outer support rod 601 are arranged side by side; the inner wrist ring 502 and the outer wrist ring 602 are at the same height. Thus, the crossbar can pass through both the inner wrist ring 502 and the outer wrist ring 602 simultaneously, and by pulling the crossbar upwards or pressing it downwards, the inner piston 5 and the outer piston 6 can be moved synchronously upwards or downwards via the inner wrist ring 502, the outer wrist ring 602, the inner support rod 501, and the outer support rod 601.

[0081] In other embodiments, to ensure the uniformity of force on the inner piston 5 when it moves under external force, the number of inner support rods 501 is set to be an even number, and they are divided into two groups. The two groups are arranged opposite each other along the circumference of the inner piston 5, and the inner support rods 501 in the same group are arranged along the same radial direction of the inner piston 5.

[0082] As an example, two inner support rods 501 can be provided, and the two inner support rods 501 are symmetrically arranged along the circumference of the inner piston 5. In this way, when the inner piston 5 is moved by the crossbar and the inner hand ring 502, the symmetrical arrangement of the two inner support rods 501 along the circumference ensures that the inner piston 5 is simultaneously subjected to two forces that are opposite each other in the vertical direction, thereby avoiding the inner piston 5 being in a state of unilateral force.

[0083] Similarly, to ensure the uniformity of force when the outer piston 6 moves under the action of external force, the number of outer support rods 601 is set to be even, and they are divided into two groups. The two groups are arranged opposite each other along the circumference of the outer piston 6, and the outer support rods 601 in the same group are arranged along the same radial direction of the outer piston 6.

[0084] As an example, two outer support rods 601 can be provided, and the two outer support rods 601 are symmetrically arranged around the circumference of the outer piston 6. In this way, when the outer piston 6 is moved by the crossbar and the outer hand ring 602, the symmetrical arrangement of the two outer support rods 601 around the circumference ensures that the outer piston 6 is simultaneously subjected to two forces that are opposite each other in the vertical direction, thereby avoiding the outer piston 6 being in a state of being subjected to force on one side.

[0085] In other embodiments, to ensure the uniformity of liquid delivery from the annular cavity to the outer cavity, multiple switching valves 4 are provided at the bottom of the outer measuring cylinder 3, arranged circumferentially, allowing the annular cavity to communicate with the outer cavity simultaneously through multiple open switching valves 4. Correspondingly, multiple connecting pipes 401 are located between the inner measuring cylinder 2 and the outer measuring cylinder 3, arranged circumferentially. This allows the annular cavity to simultaneously deliver liquid into the outer cavity through multiple connecting pipes 401.

[0086] As an example, the number of switch valves 4 at the bottom of the outer measuring cylinder 3 can be set to two, with the two switch valves 4 arranged symmetrically along the circumference.

[0087] In other embodiments, to ensure the uniformity of fluid delivery from the upper annular cavity to the lower annular cavity, multiple external bidirectional differential pressure valves 8 are provided and arranged circumferentially. This allows the upper annular cavity to simultaneously deliver fluid into the lower annular cavity through multiple external bidirectional differential pressure valves 8.

[0088] As an example, the number of external bidirectional differential pressure valves 8 can be set to two, and they are arranged symmetrically along the circumference.

[0089] In other embodiments, to ensure efficient liquid exchange between the upper column cavity and the upper annular cavity, multiple through holes 201 are provided, arranged circumferentially. Thus, when the liquid levels in the upper column cavity and the upper annular cavity are inconsistent, the liquid at the higher level can be simultaneously supplied to the liquid at the lower level through multiple through holes 201, thereby quickly achieving uniform liquid levels in the upper column cavity and the upper annular cavity.

[0090] In other embodiments, to improve the accuracy of the measurement results, a level is provided on the base 1. The level can be positioned on top of the upper base plate 101 for easy observation by the operator. This ensures the levelness of the road and bridge surface permeability coefficient measuring device, preventing deviations from affecting the accuracy of the measurement results.

[0091] Another embodiment of the present invention provides a method for determining the surface permeability coefficient of roads and bridges, which employs a device for determining the surface permeability coefficient of roads and bridges. The method for determining the surface permeability coefficient of roads and bridges includes the following steps:

[0092] S1. Clean the test area on the surface of the road and bridge;

[0093] S2. Place the road and bridge surface permeability coefficient measuring device in the test area. An inner cavity and an outer cavity are formed between the base 1 and the road and bridge surface.

[0094] S3. Add water into the inner measuring cylinder 2 and / or the annular cavity. Driven by the water flow, the inner piston 5 moves to the bottom of the inner measuring cylinder 2, and the outer piston 6 moves to the bottom of the annular cavity. With the through hole 201 connected, the liquid levels in the inner measuring cylinder 2 and the annular cavity are the same.

[0095] S4. Synchronously drive the inner piston 5 and the outer piston 6 to move upward, forming a pressure difference between the upper column chamber and the lower column chamber. Under the action of the pressure difference, the inner bidirectional pressure difference valve 7 opens, and the water in the upper column chamber enters the lower column chamber; at the same time, a pressure difference is formed between the upper ring chamber and the lower ring chamber. Under the action of the pressure difference, the outer bidirectional pressure difference valve 8 opens, and the water in the upper ring chamber enters the lower ring chamber.

[0096] S5. Open the switch valve 4. The water in the lower column chamber enters the inner cavity and squeezes the air in the inner cavity to the top of the liquid surface in the lower column chamber. The water in the lower ring chamber enters the outer cavity and squeezes the air in the outer cavity to the top of the liquid surface in the lower ring chamber.

[0097] S6. Close valve 4;

[0098] S7. Simultaneously, the inner piston 5 and the outer piston 6 move downwards to contact the liquid surface, creating a pressure difference between the upper and lower column chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve 7 opens, allowing air above the liquid surface in the lower column chamber to enter the upper column chamber. At the same time, a pressure difference is created between the upper and lower ring chambers. Under the action of the pressure difference, the outer bidirectional pressure difference valve 8 opens, allowing air above the liquid surface in the lower ring chamber to enter the upper ring chamber.

[0099] S8. Simultaneously, the inner piston 5 and the outer piston 6 move upward, creating a pressure difference between the upper and lower cylinder chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve 7 opens, allowing water in the upper cylinder chamber to enter the lower cylinder chamber until the liquid level in the lower cylinder chamber reaches the first preset scale V1, maintaining the position of the inner piston 5 and the outer piston 6. At the same time, a pressure difference is created between the upper and lower ring chambers, and under the action of the pressure difference, the outer bidirectional pressure difference valve 8 opens, allowing water in the upper ring chamber to enter the lower ring chamber.

[0100] S9. Simultaneously release the inner piston 5 and the outer piston 6, and open the switch valve 4 at the same time. Record the time t taken for the liquid level in the column cavity to reach the second preset scale V2.

[0101] S10. Calculate the permeability coefficient Cw = (V2 - V1) / t;

[0102] Specifically, a higher permeability coefficient indicates a higher pavement porosity or interconnected voids in the structure, allowing rainwater to seep into the pavement. This infiltrated water, under repeated vehicle loads, creates dynamic water pressure, accelerating the separation of asphalt from aggregates, or causing freeze-thaw damage and bottom voids in cement concrete pavements, significantly shortening the pavement's lifespan. Conversely, a lower permeability coefficient means weaker drainage capacity, making it difficult for rainwater to quickly penetrate the pavement and causing a water film to form on the surface. This water film significantly reduces tire-road adhesion, increasing braking distance, and especially at high speeds, can lead to skidding, hydroplaning, and other safety hazards.

[0103] S11. Change the test area and repeat steps S1-S10.

[0104] Specifically, multiple permeability coefficients can be obtained through repeated tests, and then the average value can be calculated to obtain the permeability coefficient of the road and bridge surface.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A device for measuring the surface permeability coefficient of roads and bridges, characterized in that, The system includes a base, which is placed on the surface of a road or bridge, forming an inner cavity and an outer cavity between the base and the surface. The outer cavity is fitted around the outer periphery of the inner cavity. The bottom of the base has an inner seal and an outer seal; the inner seal seals the inner cavity, and the outer seal seals the outer cavity. The top of the base has an inner measuring cylinder and an outer measuring cylinder, with the outer measuring cylinder fitted around the outer periphery of the inner measuring cylinder, forming an annular cavity between them. Both the inner and outer measuring cylinders have a switch valve at their bottom. The inner measuring cylinder is connected to the inner cavity through an open switch valve, and the annular cavity is connected to the outer cavity through an open switch valve. A through hole is provided on the peripheral wall of the inner measuring cylinder, connecting the inner measuring cylinder and the annular cavity. The inner measuring cylinder contains… An inner piston is inserted into the inner measuring cylinder, forming a piston-like fit with the inner measuring cylinder and dividing the inner measuring cylinder into an upper and lower cylindrical cavity. An internal two-way differential pressure valve is installed on the inner piston. When the internal two-way differential pressure valve is open, it connects the upper and lower cylindrical cavity. The weight and sliding friction of the inner piston are in a dynamic equilibrium state. An outer piston is inserted into the annular cavity, forming a piston-like fit with both the inner and outer measuring cylinders and dividing the annular cavity into an upper and lower annular cavity. An external two-way differential pressure valve is installed on the outer piston. When the external two-way differential pressure valve is open, it connects the upper and lower annular cavity. The weight and sliding friction of the outer piston are in a dynamic equilibrium state. Both the inner and outer measuring cylinders are made of transparent material, and graduation lines are set on the peripheral wall of the inner measuring cylinder.

2. The device for measuring the surface permeability coefficient of roads and bridges according to claim 1, characterized in that, An inner support rod is provided at the top of the inner piston, extending in a direction parallel to the axis of the inner measuring cylinder, and an inner hand ring is provided at the top of the inner support rod; an outer support rod is provided at the top of the outer piston, extending in a direction parallel to the axis of the outer measuring cylinder, and an outer hand ring is provided at the top of the outer support rod.

3. The road and bridge surface permeability coefficient measuring device according to claim 2, characterized in that, The inner and outer support rods are installed side by side; the inner and outer wristbands are at the same height.

4. The device for measuring the surface permeability coefficient of roads and bridges according to claim 2, characterized in that, There are an even number of inner support rods, which are divided into two groups. The two groups are arranged opposite each other along the circumference of the inner piston, and the inner support rods in the same group are arranged along the same radial direction of the inner piston.

5. The device for measuring the surface permeability coefficient of roads and bridges according to claim 2, characterized in that, There are an even number of outer support rods, which are divided into two groups. The two groups are arranged opposite each other along the circumference of the outer piston, and the outer support rods in the same group are arranged along the same radial direction of the outer piston.

6. The device for measuring the surface permeability coefficient of roads and bridges according to claim 1, characterized in that, There are multiple switching valves at the bottom of the outer measuring cylinder, arranged circumferentially, and the annular cavity can be connected to the outer cavity simultaneously through multiple open switching valves.

7. The device for measuring the surface permeability coefficient of roads and bridges according to claim 1, characterized in that, There are multiple external bidirectional differential pressure valves, arranged circumferentially.

8. The device for measuring the surface permeability coefficient of roads and bridges according to claim 1, characterized in that, There are multiple through holes, arranged circumferentially.

9. The device for measuring the surface permeability coefficient of roads and bridges according to claim 1, characterized in that, A level is installed on the base.

10. A method for determining the surface permeability coefficient of roads and bridges, characterized in that, Using the road and bridge surface permeability coefficient measuring device as described in claim 1, the method for measuring the road and bridge surface permeability coefficient includes the following steps: S1. Clean the test area on the surface of the road and bridge; S2. Place the road and bridge surface permeability coefficient measuring device in the test area, with an inner cavity and an outer cavity formed between the base and the road and bridge surface. S3. Add water into the inner measuring cylinder and / or the annular cavity. Driven by the water flow, the inner piston moves to the bottom of the inner measuring cylinder and the outer piston moves to the bottom of the annular cavity. With the through hole connected, the liquid levels in the inner measuring cylinder and the annular cavity are the same. S4. Synchronously drive the inner piston and outer piston to move upward, forming a pressure difference between the upper and lower cylinder chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve opens, and the water in the upper cylinder chamber enters the lower cylinder chamber; at the same time, a pressure difference is formed between the upper and lower ring chambers. Under the action of the pressure difference, the outer bidirectional pressure difference valve opens, and the water in the upper ring chamber enters the lower ring chamber. S5. Open the switch valve, and the water in the lower column chamber enters the inner cavity, and squeezes the air in the inner cavity to the top of the liquid surface in the lower column chamber. The water in the lower ring chamber enters the outer cavity, and squeezes the air in the outer cavity to the top of the liquid surface in the lower ring chamber. S6. Close the switch valve; S7. Simultaneously, the inner and outer pistons move downwards to contact the liquid surface, creating a pressure difference between the upper and lower column chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve opens, allowing air above the liquid surface in the lower column chamber to enter the upper column chamber. At the same time, a pressure difference is created between the upper and lower ring chambers. Under the action of the pressure difference, the outer bidirectional pressure difference valve opens, allowing air above the liquid surface in the lower ring chamber to enter the upper ring chamber. S8. Simultaneously drive the inner piston and outer piston to move upward, forming a pressure difference between the upper and lower cylinder chambers. Under the action of the pressure difference, the inner bidirectional pressure difference valve opens, and the water in the upper cylinder chamber enters the lower cylinder chamber until the liquid level in the lower cylinder chamber reaches the first preset scale V1, maintaining the position of the inner piston and outer piston; at the same time, a pressure difference is formed between the upper and lower ring chambers. Under the action of the pressure difference, the outer bidirectional pressure difference valve opens, and the water in the upper ring chamber enters the lower ring chamber. S9. Simultaneously release the inner and outer pistons, open the switch valve, and record the time t it takes for the liquid level in the column cavity to reach the second preset scale V2. S10. Calculate the permeability coefficient Cw = (V2 - V1) / t; S11. Change the test area and repeat steps S1-S10.

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