Constant head water seepage testing device based on rut test board

Abstract

The utility model discloses a constant head water seepage testing device based on a rut test board, belongs to the technical field of pavement water seepage coefficient testing, and is mainly used for testing the water seepage coefficient of the rut test board. The utility model provides a constant head water seepage testing device based on a rut test board. A water head control assembly comprises a water inlet bucket and a water outlet bucket, wherein a first water outlet pipe and a second water inlet pipe are respectively arranged below the water inlet bucket and the water outlet bucket; the track test plate clamp comprises a side plate, a bottom plate and a cover plate which are enclosed to form a rectangular cavity for clamping the track test plate, and the side plate is provided with a third water inlet pipe and a third water outlet pipe; a U-shaped pressure gauge is arranged between the third water inlet pipe and the third water outlet pipe. The testing device can be used for measuring the transverse and vertical permeability coefficients of the rut test board to obtain the water permeability coefficient of the drainage asphalt pavement, and can be used for testing different rut test boards to ensure the authenticity and accuracy of test data.

Description

Technical Field

[0001] The utility model relates to the technical field of pavement seepage coefficient testing, in particular to a constant head seepage testing device based on a rut test plate. Background Technique

[0002] In road construction, due to the large void ratio and surface texture depth of the porous asphalt pavement, it has outstanding advantages such as high skid resistance, low noise, suppression of water mist, and prevention of hydroplaning, and is commonly used in the construction of "sponge cities". However, during application, it is necessary to test the indoor permeability coefficient K of the porous asphalt mixture used for paving the porous asphalt pavement; the existing testing methods for the permeability coefficient K include two methods: "variable head" and "constant head". In the "constant head method", the head difference on both sides is controlled to be a fixed value during the test, while in the "variable head method", the head height changes continuously during the test.

[0003] For the test of the permeability coefficient K of the porous asphalt mixture, considering the pressure influence caused by vehicle driving on the road surface, currently, a rut test plate is often used for testing, and the rut test plate made of the porous asphalt mixture is used to simulate the porous asphalt pavement paved with the porous asphalt mixture; considering the two different situations of lateral seepage and vertical seepage of rainwater on the road, and since the vertical and lateral permeability coefficients of the porous asphalt pavement are usually different, generally speaking, the lateral permeability coefficient is larger than the vertical permeability coefficient, and the lateral permeability coefficient is not significantly changed by traffic compaction and is relatively stable; in addition, the lateral drainage path of rainwater on the road surface is longer, so it is very necessary to study the lateral drainage of the porous asphalt pavement, so the test is divided into two types: vertical permeability coefficient and lateral permeability coefficient.

[0004] The existing testing methods for the vertical permeability coefficient can refer to the asphalt mixture permeability test in T0730-2011 in JTG E60-2008 "Code for Field Testing of Highway Subgrade and Pavement" or JTG E20-2011 "Code for Tests of Bitumen and Bituminous Mixtures for Highway Engineering", and the testing device used is as Figure 1As shown in the figure, the test device is divided into an upper structure and a lower structure. The upper part is a graduated water measuring cylinder made of transparent plexiglass with a volume of 600 ml. There are thick markings at 100 ml and 500 ml. It is connected to the base through a 10-mm thin tube below, and there is a switch in the middle. During the test, the instrument is placed on the rut test plate specimen to be tested, and it can only be tested after being sealed with sealant at the bottom. The whole process of this test device requires manual operation. While judging the water level drop with the naked eye, the stopwatch is manually started. At this time, there is a time difference between reception and reaction, resulting in deviations in the measurement of the water seepage volume and seepage time, inaccurate calculation of the seepage coefficient, and a relatively complex operation process, often requiring multiple people to cooperate. And because this instrument uses the "variable head" test method, it is only applicable to testing materials with a small permeability coefficient. For the porous asphalt pavement with a strong permeability ability, this test method completely fails to meet its test requirements. The existing test methods for the transverse permeability coefficient mainly use the "constant head" method. The test device used during the test can refer to Figure 2 , during the test, by adjusting the water flow rate at the water inlet end, fixing the head difference, and after the water flow is stable, starting the stopwatch to time and measuring the volume of the liquid flowing out; the main problems of this test device are: there are too many human interference factors, such as the need for manual regulation of the flow rate and timing, resulting in large errors in its test data; it is difficult for the test data to fully reflect the true situation of the specimen; and this device has many restrictions on the test specimen and is difficult to meet the test requirements of different specimens. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a constant head water seepage test device based on a rut test plate, which is mainly used for testing the seepage coefficient of a rut test plate, so as to achieve the purpose of measuring the transverse permeability coefficient and vertical permeability coefficient of the rut test plate by using the "constant head" test method, and then obtaining the seepage coefficient of the porous asphalt pavement. Moreover, it can test different rut test plates and ensure the authenticity and accuracy of the test data.

[0006] A constant-head water permeability test device based on a rut test plate disclosed by the utility model includes a water head control component and a rut test plate clamp. The water head control component includes a water inlet bucket and a water outlet bucket. The water inlet bucket has an open top, and a first water outlet pipe is provided on the water inlet bucket. The first water outlet pipe is arranged below the water inlet bucket, and a water inlet bucket valve is provided on the first water outlet pipe. The water outlet bucket has an open top, and a second water inlet pipe is provided on the water outlet bucket. The second water inlet pipe is arranged below the water outlet bucket, and a water outlet bucket valve is provided on the second water inlet pipe. The rut test plate clamp includes a bottom plate, a cover plate and side plates. The four side plates, together with the bottom plate and the cover plate, enclose a rectangular cavity for clamping the rut test plate. The bottom plate is fixedly connected to the four side plates, and the cover plate is bolted to the four side plates. The side plates are provided with a third water inlet pipe and a third water outlet pipe. A first water delivery pipe is arranged between the first water outlet pipe and the third water inlet pipe, and a second water delivery pipe is arranged between the second water inlet pipe and the third water outlet pipe. A flow meter is provided at one end of the first water delivery pipe close to the water inlet bucket. The input port of the third water inlet pipe is communicated with a U-shaped pressure gauge, and the other end of the U-shaped pressure gauge is connected to the output port of the third water outlet pipe.

[0007] Further, the rut test plate clamp is a vertical clamp. The side plates are in a trapezoidal shape with a wider top and a narrower bottom. The third water inlet pipe and the third water outlet pipe are arranged on the same side plate. The third water inlet pipe is arranged above the third water outlet pipe and is on the same straight line as the third water outlet pipe. The inner side of each side plate is coated with glass glue for sealing the periphery of the rut test plate.

[0008] As a preferred method, a side observation window is provided on the side plate, and a top observation window is provided on the cover plate. Transparent sealing plates for blocking the windows are provided at the side observation window and the top observation window.

[0009] Further, the rut test plate clamp is a horizontal clamp. The third water inlet pipe is arranged on the side plate close to the water inlet bucket, and the third water outlet pipe is arranged on the side plate close to the water outlet bucket. The third water inlet pipe and the third water outlet pipe are in different vertical planes on the same horizontal plane. Waterproof silicone pads adapted to the size of the rut test plate are provided above the bottom plate and below the cover plate. Waterproof silicone pads adapted to the size of the rut test plate are provided on the inner side of the side plate between the third water inlet pipe and the third water outlet pipe.

[0010] As a preferred method, a water stop plate is provided at the water outlet of the third water inlet pipe, and a plurality of through holes evenly distributed on the water stop plate are provided on the water stop plate.

[0011] As a preferred method, pads with different heights are provided below the bottom plate.

[0012] Furthermore, a first water inlet pipe is also provided on the water inlet bucket. The first water inlet pipe is arranged above the water inlet bucket and is on the same straight line as the first water outlet pipe. A second water outlet pipe is also provided on the water outlet bucket. The second water outlet pipe is arranged above the water outlet bucket and is on the same straight line as the second water inlet pipe.

[0013] Furthermore, a sealing ring adapted to the side plate is also provided below the cover plate.

[0014] The beneficial effects of the present utility model are as follows: According to the required horizontal drainage permeability coefficient and vertical permeability drainage coefficient to be measured, only different rut test plate jigs need to be replaced, with strong universality, simple and convenient operation, and can be operated by a single person; and after the cover plate of the rut test plate jig is bolted to the side plate, a sealed cavity can be formed, enabling the water flow to pass through the cross-section of the test piece in the whole section, so that the test data is more real; and the rut test plate jig is provided to clamp the rut test plate in a sealed space, so as to fill the rut test plate jig with water to form a sealed water-filled chamber, so that the digital display flowmeter and U-shaped pressure gauge provided can monitor the water flow and pressure difference passing through the rut test plate, with high accuracy, good parallelism, few human interference factors, and high reliability of the obtained experimental data. The accuracy of the permeability coefficient of the rut test plate calculated using such data is high and more real; that is, the constant head water permeability test device based on the rut test plate can be used to measure the horizontal permeability coefficient and vertical permeability coefficient of the rut test plate, and further achieve the purpose of obtaining the water permeability coefficient of the porous asphalt pavement, and can test different rut test plates, and ensure the authenticity and accuracy of the test data. Description of the Drawings

[0015] Figure 1 : An existing device for testing the vertical permeability coefficient;

[0016] Figure 2 : An existing device for testing the horizontal permeability coefficient;

[0017] Figure 3 : The test device provided by the present utility model for testing the vertical permeability coefficient;

[0018] Figure 4 : Structural schematic diagram of the vertical fixture;

[0019] Figure 5 : Side view of the vertical fixture;

[0020] Figure 6 : The test device provided by the present utility model for testing the horizontal permeability coefficient;

[0021] Figure 7 : Structural schematic diagram of the horizontal fixture;

[0022] Figure 8 : Side view of the horizontal fixture;

[0023] Reference numerals: 1 - water head control assembly; 11 - water inlet bucket; 111 - first water inlet pipe; 112 - first water outlet pipe; 113 - water inlet bucket valve; 12 - water outlet bucket; 121 - second water inlet pipe; 122 - second water outlet pipe; 123 - water outlet bucket valve; 13 - first water delivery pipe; 14 - second water delivery pipe; 2 - rut test plate fixture; 21 - bottom plate; 22 - side plate; 221 - side observation window; 23 - cover plate; 231 - top observation window; 24 - third water inlet pipe; 25 - third water outlet pipe; 26 - water stop plate; 261 - through hole; 27 - transparent sealing plate; 28 - waterproof silicone pad; 29 - spacer block; 3 - flow meter; 4 - U-shaped manometer; 5 - rut test plate. Detailed implementation mode

[0024] The present utility model will be further described below.

[0025] The present utility model provides a constant water head seepage test device based on a rut test plate, which is mainly used for testing the seepage coefficient of a rut test plate, and includes a water head control assembly 1 and a rut test plate fixture 2. The water head control assembly 1 includes a water inlet bucket 11 and a water outlet bucket 12. The water inlet bucket 11 has an open top. A first water outlet pipe 112 is provided on the water inlet bucket 11. The first water outlet pipe 112 is arranged below the water inlet bucket 11, and a water inlet bucket valve 113 is provided on the first water outlet pipe 112. The water outlet bucket 12 has an open top. A second water inlet pipe 121 is provided on the water outlet bucket 12. The second water inlet pipe 121 is arranged below the water outlet bucket 12, and a water outlet bucket valve 123 is provided on the second water inlet pipe 121. The rut test plate fixture 2 includes a bottom plate 21, a cover plate 23 and side plates 22. The four side plates 22, the bottom plate 21 and the cover plate 23 enclose a rectangular cavity for clamping the rut test plate 5. The bottom plate 21 is fixedly connected to the four side plates 22, and the cover plate 23 is bolted to the four side plates 22. A third water inlet pipe 24 and a third water outlet pipe 25 are provided on the side plates 22. A first water delivery pipe 13 is provided between the first water outlet pipe 112 and the third water inlet pipe 24. A second water delivery pipe 14 is provided between the second water inlet pipe 121 and the third water outlet pipe 25. A flow meter 3 is provided at one end of the first water delivery pipe 13 close to the water inlet bucket 11. The input port of the third water inlet pipe 24 is communicated with a U-shaped manometer 4, and the other end of the U-shaped manometer 4 is connected to the output port of the third water outlet pipe 25.

[0026] As Figure 3 、 Figure 6As shown in the figure, the first water outlet pipe 112 of the water inlet bucket 11 is connected to the third water inlet pipe 24 of the rut test plate fixture 2 through the first water delivery pipe 13. The third water outlet pipe 25 of the rut test plate fixture 2 is connected to the second water inlet pipe 121 of the water outlet bucket 12 through the second water delivery pipe 14. The first water outlet pipe 112 is arranged below the water inlet bucket 11 to ensure the stability of the water inlet flow rate and the sufficiency of the water source. The second water inlet pipe 121 is arranged below the water outlet bucket 12 to ensure that the water output from the third water outlet pipe 25 will not cause a change in water pressure due to the height difference. The top of the water inlet bucket 11 is open to ensure that the water pressure inside the water inlet bucket 11 is always the same as the atmospheric pressure, avoiding the change in water pressure caused by the change in the water volume inside the water inlet bucket 11, which may lead to a change in the water flow rate output from the first water outlet pipe 112. At the same time, the external faucet can directly deliver water to the water inlet bucket 11 from the top opening of the water inlet bucket 11 to continuously provide a water source. The top of the water outlet bucket 12 is open to ensure that the water pressure inside the water outlet bucket 12 is always the same as the atmospheric pressure, so that the water flow rate of the second water inlet pipe 121 delivering water to the water outlet bucket 12 is always the same as the water flow rate output from the third water outlet pipe 25 on the rut test plate fixture 2, and the third water outlet pipe 25 will not be unable to discharge water normally due to the internal water pressure of the water outlet bucket 12. A water inlet bucket valve 113 is arranged on the first water outlet pipe 112, and a water outlet bucket valve 123 is arranged on the second water inlet pipe 121 to control the water outlet of the water inlet bucket 11 and the water inlet of the water outlet bucket 12. During the test, the relative height between the water inlet bucket 11 and the water outlet bucket 12 can be adjusted to regulate the head pressure. The rut test plate fixture 2 is designed as a rectangular body, that is, the side plate 22 and the bottom plate 21 enclose a frame-shaped structure, which matches the rectangular rut test plate 5 to clamp the rut test plate 5 whose permeability coefficient is to be tested. During the test, according to the transverse or vertical permeability coefficient of the rut test plate 5 to be tested, a suitable rut test plate fixture 2 is selected, and the positions of the third water outlet pipe 25 and the third water inlet pipe 24 are reasonably set. And a cover plate 23 bolted to the side plate 22 is provided, which is convenient for disassembling and installing the cover plate 23, installing and removing the rut test plate 5, and at the same time can form a sealed cavity for the entire rut test plate fixture 2, ensuring that during the subsequent constant head test, after the entire fixture is filled with water, water can only flow out from the third water outlet pipe 25, so as to ensure that a stable and accurate water flow rate and pressure difference can be measured using this rut test plate fixture 2. A flow meter 3 is arranged at one end of the first water delivery pipe 13 close to the first water outlet pipe 112. This flow meter 3 is a digital display flow meter, which can display the flow rate and the cumulative flow. During actual use, according to the different sizes of the rut test plates 5 to be tested, a flow meter 3 with a corresponding range can be selected for monitoring. During the test, after the water flow of the device to be tested is stable, the value can be directly read and calculated.A U-shaped manometer 4 communicating with both is provided between the first water delivery pipe 13 and the second water delivery pipe 14. Specifically, one end of the U-shaped manometer 4 communicates with the input port of the third water inlet pipe 24, and the other end communicates with the output port of the third water outlet pipe 25. During the test, first connect both ends of the manometer to the third water inlet pipe 24 and the third water outlet pipe 25 respectively through hoses. When the water permeates through the test piece, the numerical difference on the U-shaped manometer can be directly read, that is, the water level height difference between the first water outlet pipe and the second water inlet pipe.;

[0027] When using this constant head water permeability test device based on the rut test plate to test the permeability coefficient of the rut test plate 5, first connect the external water faucet to the top opening of the water inlet bucket 11, continuously supply water to the water inlet bucket 11, open the water inlet bucket valve 113, close the water outlet bucket valve 123, and inject water into the rut test plate fixture 2 holding the rut test plate 5 until the entire rut test plate fixture 2 is filled with water. Then open the water outlet bucket valve 123. Since both ends of the U-shaped manometer 4 are connected to the third water inlet pipe 24 and the third water outlet pipe 25 through hoses, when waiting for the water to permeate through the rut test plate 5, the numerical difference on the U-shaped manometer can be directly read, that is, the water level height difference h between the first water outlet pipe and the second water inlet pipe; After the water head is stable, start observing the flowmeter 3. Select a time period, that is, the test start time t1 and the test end time t2, observe and record the cumulative flow monitored on the flowmeter 3, and calculate the difference to obtain the total flow Q flowing through the rut test plate 5 during this time period; Calculate according to the formula for testing the permeability coefficient under constant head to obtain the vertical permeability coefficient. The formula for testing the permeability coefficient under constant head is as follows:

[0028]

[0029] Where: K: Permeability coefficient, cm / s; L: Length of the rut test plate, cm; h: Water level height difference (water level height difference between the first water outlet pipe and the second water inlet pipe), cm; Q: Total flow, cm 3 ; A: Cross-sectional area of the rut test plate, cm 2 ; t1: Test start time, s; t2: Test end time, s.

[0030] Using this constant-head water permeability testing device based on the rut test plate, water flow is input into the rut test plate fixture 2 by means of the water head control component 1. Then, through the sealed rut test plate fixture 2 formed by enclosing the side plate 22 with the bottom plate 21 and the cover plate 23, it can be adjusted according to the size of the rut test plate 5. For example, it can be raised or the side wall can be blocked using a waterproof silicone pad 28 to be applicable to rut test plates 5 of different sizes, while ensuring that the water flow can pass through the cross-section of the specimen in the full section, so that the test data is more real. At the same time, the rut test plate fixture 2 and the water head control component 1 are connected by the first water delivery pipe 13 and the second water delivery pipe 14. Therefore, during the test, only different rut test plate fixtures 2 need to be replaced according to the required lateral drainage permeability coefficient and vertical permeability drainage coefficient to be measured. It has strong universality, simple and convenient operation, and can be operated by a single person. Moreover, the rut test plate fixture 2 is set to clamp the rut test plate 5 in a sealed space so that the rut test plate fixture 2 can be filled with water to form a sealed water-filled chamber, so that the digital display flowmeter 3 and the U-shaped manometer 4 are set to monitor the water flow rate and pressure difference passing through the rut test plate 5. The accuracy is relatively high, the parallelism is good, the human interference factors are less, and the reliability of the obtained experimental data is high. The accuracy of the permeability coefficient of the rut test plate 5 calculated using such data is high and more real. Therefore, using this constant-head water permeability testing device based on the rut test plate can achieve the purpose of measuring the lateral permeability coefficient and vertical permeability coefficient of the rut test plate, and then obtaining the water permeability coefficient of the porous asphalt pavement, and can test different rut test plates, and ensure the authenticity and accuracy of the test data.

[0031] To test the vertical permeability coefficient of the rut test plate in order to obtain the vertical permeability coefficient of the porous asphalt pavement, such as Figure 3 = Figure 5As shown, the rut test plate fixture 2 is a vertical fixture. The side plate 22 is in the shape of a trapezoid with a wider top and a narrower bottom. The third water inlet pipe 24 and the third water outlet pipe 25 are arranged on the same side plate 22. The third water inlet pipe 24 is arranged above the third water outlet pipe 25 and is on the same straight line as the third water outlet pipe 25. The inner side of each side plate 22 is coated with glass glue for sealing the periphery of the rut test plate 5. The side plate 22 is set as a trapezoid with a wider top and a narrower bottom, so that the frame formed by enclosing four side plates 22 is a frame with a wider top and a narrower bottom, and together with the bottom plate 21, it forms a funnel-shaped cavity for clamping the rut test plate 5. Such a setting enables the vertical fixture to be applicable to rut test plates 5 of various sizes. Just place the rut test plate 5 into the vertical fixture. Since the cavity gradually decreases from top to bottom, during the process of lowering the rut test plate 5, it will be fixed and clamped at a preset height by the frictional force and supporting force provided by the side plate 22. It should be noted that the rut test plate 5 needs to be placed below the third water inlet pipe 24 and above the third water outlet pipe 25. Since the inner side of the side plate 22 is coated with glass glue, when the rut test plate 5 is clamped into the inner side of the side plate 22, the glass glue will also adhere to the periphery of the rut test plate 5 to seal the flow path around the rut test plate 5, thereby ensuring that only vertical seepage occurs in the rut test plate 5. To ensure the tightness around the rut test plate 5, glass glue can also be first applied all around the rut test plate 5. The third water inlet pipe 24 and the third water outlet pipe 25 are arranged on the same side plate 22 to ensure that the pressure difference measured by the U-shaped manometer 4 is the water flow pressure difference of the same vertical section. During use, first place the rut test plate 5 to be tested. The rut test plate 5 will be fixed and clamped at a preset height by the frictional force and supporting force provided by the side plate 22. Then place the cover plate 23 and tighten the bolts to fix the cover plate 23 on the side plate 22 to ensure the tightness of the vertical fixture. Water enters from the top opening of the water inlet bucket 11. Open the water inlet bucket valve 113 and close the water outlet bucket valve 123 to fill the entire vertical fixture with water. Since both ends of the U-shaped manometer 4 are connected to the third water inlet pipe 24 and the third water outlet pipe 25 through hoses, when waiting for the water to penetrate the rut test plate 5, the numerical difference on the U-shaped manometer can be directly read, that is, the water level height difference h between the first water outlet pipe and the second water inlet pipe. Then open the water outlet bucket valve 123. After the water head is stable, start observing the flowmeter 3. Select a time period, that is, the test start time t1 and the test end time t2, observe and record the cumulative flow monitored by the flowmeter 3, and calculate the difference to obtain the total flow Q flowing through the rut test plate 5 during this time period. The vertical permeability coefficient can be calculated according to the formula for testing the permeability coefficient under a constant water head. The formula for testing the permeability coefficient under a constant water head is as follows:

[0032]

[0033] Where: K: Permeability coefficient, cm / s; L: Length of the rut test plate, cm; h: Water level height difference (water level height difference between the first outlet pipe and the second inlet pipe), cm; Q: Total flow rate, cm 3 ; A: Cross-sectional area of the rut test plate, cm 2 ; t1: Test start time, s; t2: Test end time, s.

[0034] For facilitating the observation of the water flow states at the top and the side during the test, as Figures 3 - 5 shown, a side observation window 221 is formed on the side plate 22, a top observation window 231 is provided on the cover plate 23, and transparent sealing plates 27 for sealing the windows are arranged at both the side observation window 221 and the top observation window 231; by forming the top observation window 231 and the side observation window 221 and arranging the transparent sealing plates 27 on the top observation window 231 and the side observation window 221, operators can observe the internal water flow states from the outside. The above transparent sealing plates 27 can be made of acrylic plates, transparent glasses, etc.; as a preferred method, for facilitating the disassembly, assembly and replacement of the transparent sealing plates 27, as Figure 4 shown, the transparent sealing plates 27 are detachably arranged on the cover plate 23 or the side plate 22 through bolt connections; specifically, the vertical fixture is 200 mm high, the top opening size is 356×356 mm, and the bottom size is 276×276 mm, and it is applicable to standard rut plates of 300×300×5 mm and double-layer rut plates of 300×300×7 mm.

[0035] To test the transverse permeability coefficient of the rut test plate 5 so as to obtain the transverse permeability coefficient of the porous asphalt pavement, as Figures 6 - 8As shown in the figure, the rut test plate fixture 2 is a transverse fixture. The third water inlet pipe 24 is arranged on the side plate 22 close to the water inlet bucket 11, and the third water outlet pipe 25 is arranged on the side plate 22 close to the water outlet bucket 12. The third water inlet pipe 24 and the third water outlet pipe 25 are located in different vertical planes of the same horizontal plane. Waterproof silicone pads 28 adapted to the size of the rut test plate 5 are provided above the bottom plate 21 and below the cover plate 23. Waterproof silicone pads 28 adapted to the size of the rut test plate 5 are provided on the inner side of the side plate 22 between the third water inlet pipe 24 and the third water outlet pipe 25. Placing the waterproof silicone pads 28 above the bottom plate 21 and below the cover plate 23, and on the inner side of the side plate 22 between the third water inlet pipe 24 and the third water outlet pipe 25, that is, on the inner sides of the two side plates 22 not connected to the third water inlet pipe 24 and the third water outlet pipe 25, is to seal all the gaps around the rut test plate 5 except the two sides close to the third water inlet pipe 24 and the third water outlet pipe 25, so that the water input from the third water inlet pipe 24 can only flow along the transverse direction of the rut test plate 5 to the third water outlet pipe 25, to ensure the accuracy of the measured transverse permeability coefficient and reduce the error caused by surrounding water seepage. The third water inlet pipe 24 and the third water outlet pipe 25 are arranged in the same horizontal plane to ensure that the pressure difference measured by the U-shaped manometer 4 is the water flow pressure difference of the same cross-section. The third water inlet pipe 24 and the third water outlet pipe 25 are arranged in different vertical planes to enable the third water inlet pipe 24 and the third water outlet pipe 25 to be staggered, to avoid the water flowing through the cross-section of the rut test plate 5 flowing out directly from the shortest path, resulting in a shorter measured water seepage time and affecting the accuracy of the transverse permeability coefficient. When conducting the transverse permeability coefficient test, first install the rut test plate 5. The waterproof silicone pads 28 provided on the bottom plate 21, the waterproof silicone pads 28 provided on the cover plate 23, and the waterproof silicone pads 28 provided on the inner sides of the two side plates 22 seal the periphery of the rut test plate 5. Then bolt the cover plate 23 and the side plate 22. Open the water inlet bucket valve 113 on the first water outlet pipe 112 and close the water outlet bucket valve 123 on the second water inlet pipe 121 to fill the entire transverse fixture with water. Since both ends of the U-shaped manometer 4 are connected to the third water inlet pipe 24 and the third water outlet pipe 25 through hoses, when waiting for the water to penetrate the rut test plate 5, the numerical difference on the U-shaped manometer can be directly read, that is, the water level height difference h between the first water outlet pipe and the second water inlet pipe. Then open the water outlet bucket valve 123. After the water head is stable, start observing the flowmeter 3. Select a time period, that is, the test start time t1 and the test end time t2, observe and record the cumulative flow monitored by the flowmeter 3, and calculate the difference to obtain the total flow Q flowing through the rut test plate 5 during this time period. Calculate according to the formula for testing the permeability coefficient under a constant water head to obtain the transverse permeability coefficient. The formula for testing the permeability coefficient under a constant water head is as follows:

[0036]

[0037] Where: K: Permeability coefficient, cm / s; L: Length of the rut test plate, cm; h: Water level height difference (water level height difference between the first outlet pipe and the second inlet pipe), cm; Q: Total flow rate, cm 3 ; P: Value of the pressure difference; A: Cross-sectional area of the rut test plate, m 2 ; t1: Test start time, s; t2: Test end time, s.

[0038] To avoid a large water inlet pressure at the third inlet pipe 24 provided on the transverse fixture, where the water flow directly impacts the rut test plate 5, as Figures 6 - 8 shown, a water stop plate 26 is provided at the outlet of the third inlet pipe 24, and a plurality of through holes 261 evenly distributed on the water stop plate 26 are opened on the water stop plate 26; by providing the water stop plate 26 at the outlet of the third inlet pipe 24, the water output from the third inlet pipe 24 flows uniformly to the rut test plate 5 from the through holes 261 distributed on the water stop plate 26, so that the water output from the third inlet pipe 24 can flow through the entire rut test plate 5 uniformly along the transverse direction of the rut test plate 5 and finally be output from the third outlet pipe 25, ensuring that the measured transverse permeability coefficient is close to the actual transverse permeability coefficient and reducing errors caused by uneven water flow.

[0039] To facilitate the measurement of the transverse permeability coefficient of the rut test plate 5 at different slopes, pads 29 with different heights are provided below the bottom plate 21; by providing pads 29 with different heights below the bottom plate 21, the inclination degree of the bottom plate 21 can be adjusted, that is, the rut test plate 5 provided in the transverse fixture inclines with the inclination of the entire transverse fixture, so as to achieve the purpose of measuring the transverse permeability coefficient of the rut test plate 5 at different slopes. Specifically, the vertical fixture is 404×314 mm high and 80 mm in net height, and is applicable to standard rut plates of 300×300×5 mm and double-layer rut plates of 300×300×7 mm.

[0040] To facilitate the control of the water flow input of the water inlet bucket 11 and the water flow output of the water outlet bucket 12, as Figure 3 、 Figure 6As shown in the figure, a first water inlet pipe 111 is further provided on the water inlet bucket 11. The first water inlet pipe 111 is arranged above the water inlet bucket 11 and is on the same straight line as the first water outlet pipe 112. A second water outlet pipe 122 is further provided on the water outlet bucket 12. The second water outlet pipe 122 is arranged above the water outlet bucket 12 and is on the same straight line as the second water inlet pipe 121. By adding the first water inlet pipe 111 to the water inlet bucket 11, it is convenient to connect an external faucet through a hose, and it can ensure a stable water supply, ensure the water pressure in the water inlet bucket 11, avoid the change of the water delivery rate of the first water outlet pipe 112 due to the change of water pressure, resulting in errors in the water flow monitored by the flow meter 3, and the fact that the first water inlet pipe 111 and the first water outlet pipe 112 are on the same straight line can ensure the head difference in the water inlet bucket 11. By adding the second water outlet pipe 122 to the water outlet bucket 12, it is convenient to drain the water overflowing from the water outlet bucket 12 through the second water outlet pipe 122, avoid the water from spilling everywhere and affecting the experimental environment, and the water drained from the second water outlet pipe 122 can also be connected to a graduated cylinder to check the water flow Q monitored by the flow meter 3, ensure the accuracy of the monitored data, and the fact that the second water outlet pipe 122 and the second water inlet pipe 121 are on the same straight line can ensure the head difference in the water outlet bucket 12. Specifically, the water inlet bucket 11 and the water outlet bucket 12 have the same size specifications, with an internal net height of 300 mm and a diameter of 200 mm. Two water inlet pipes and water outlet pipes made of stainless steel pipes with an inner diameter of 20 mm are provided on the side of the bucket body, and the distances between the water inlet pipes and water outlet pipes from the top and bottom of the bucket body are both 30 mm.

[0041] To ensure the tightness of the rut test plate fixture 2, simulate the state of a real porous asphalt pavement, and reduce the influence of external factors on the permeability coefficient test of the rut test plate 5, a sealing ring adapted to the side plate 22 is further provided below the cover plate 23. By setting the sealing ring, the tightness between the cover plate 23 and the side plate 22 is further ensured, and the error caused by the water flow loss due to poor tightness is reduced.

Claims

1. A constant head water seepage test device based on a rutting test plate, characterized in that: The invention comprises a water head control component (1) and a rutting test plate fixture (2). The water head control component (1) comprises a water inlet bucket (11) and a water outlet bucket (12). The water inlet bucket (11) is open at the top. A first water outlet pipe (112) is provided on the water inlet bucket (11). The first water outlet pipe (112) is arranged below the water inlet bucket (11). A water inlet bucket valve (113) is provided on the first water outlet pipe (112). The water outlet bucket (12) is open at the top. A second water inlet pipe (121) is provided on the water outlet bucket (12). The second water inlet pipe (121) is arranged below the water outlet bucket (12). A water outlet bucket valve (123) is provided on the second water inlet pipe (121). The rutting test plate fixture (2) comprises a bottom plate (21), a cover plate (23) and side plates (22). The four side plates (22) are connected to the bottom plate. (21), the cover plate (23) encloses a rectangular cavity for clamping the rutting test plate (5), the bottom plate (21) and the four side plates (22) are fixedly connected, the cover plate (23) is bolted to the four side plates (22), and a third water inlet pipe (24) and a third water outlet pipe (25) are provided on the side plates (22); a first water delivery pipe (13) is provided between the first water outlet pipe (112) and the third water inlet pipe (24), and a second water delivery pipe (14) is provided between the second water inlet pipe (121) and the third water outlet pipe (25); a flow meter (3) is provided at one end of the first water delivery pipe (13) close to the water inlet bucket (11), the input port of the third water inlet pipe (24) is connected to a U-shaped pressure gauge (4), and the other end of the U-shaped pressure gauge (4) is connected to the output port of the third water outlet pipe (25).

2. A constant head water seepage test device based on a rutting test plate as claimed in claim 1, characterized in that: The rutting test plate fixture (2) is a vertical fixture, the side plate (22) is in the shape of a trapezoid that is wide at the top and narrow at the bottom, the third water inlet pipe (24) and the third water outlet pipe (25) are arranged on the same side plate (22), the third water inlet pipe (24) is arranged above the third water outlet pipe (25) and is located in the same straight line as the third water outlet pipe (25), and the inner side of each side plate (22) is coated with glass glue for sealing the rutting test plate (5) around.

3. A constant head water seepage test device based on a rutting test plate as claimed in claim 2, characterized in that: The side plate (22) is provided with a side observation window (221), the cover plate (23) is provided with a top observation window (231), and both the side observation window (221) and the top observation window (231) are provided with transparent sealing plates (27) for sealing the windows.

4. A constant head water seepage test device based on a rutting test plate as claimed in claim 1, characterized in that: The rutting test plate fixture (2) is a transverse fixture; the third water inlet pipe (24) is arranged on a side plate (22) close to the water inlet bucket (11); the third water outlet pipe (25) is arranged on a side plate (22) close to the water outlet bucket (12); the third water inlet pipe (24) and the third water outlet pipe (25) are located on different vertical planes of the same horizontal plane; a waterproof silicone pad (28) matching the size of the rutting test plate (5) is arranged above the bottom plate (21) and below the cover plate (23); and a waterproof silicone pad (28) matching the size of the rutting test plate (5) is arranged on the inner side of the side plate (22) located between the third water inlet pipe (24) and the third water outlet pipe (25).

5. A constant head water seepage test device based on a rutting test plate as claimed in claim 4, characterized in that: A water stop plate (26) is provided at the water outlet of the third water inlet pipe (24), and the water stop plate (26) is provided with a plurality of through holes (261) evenly distributed on the water stop plate (26).

6. A constant head water seepage test device based on a rutting test plate as claimed in claim 4, characterized in that: Pads (29) of different heights are provided below the bottom plate (21).

7. A constant head water seepage test device based on a rutting test plate as claimed in claim 1, characterized in that: The water inlet bucket (11) is also provided with a first water inlet pipe (111), the first water inlet pipe (111) is arranged above the water inlet bucket (11) and is located in the same straight line as the first water outlet pipe (112), and the water outlet bucket (12) is also provided with a second water outlet pipe (122), the second water outlet pipe (122) is arranged above the water outlet bucket (12) and is located in the same straight line as the second water inlet pipe (121).

8. A constant head water seepage test device based on a rutting test plate as claimed in claim 1, characterized in that: A sealing ring matched with the side plate (22) is also provided below the cover plate (23).

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