A load and water-dynamic coupling roadbed erosion and scour simulation system

Abstract

The invention discloses a load and dynamic water coupling roadbed dissolution and scouring simulation system, the water damage pressure chamber comprises a base, a pressure frame, and an upper plate, a sample base is fixed at the center of the base, a sample sleeve is installed on the sample base, the sample sleeve has a plurality of through holes, a sample with a rubber membrane is placed in the sample sleeve, an axial pressure device is fixedly installed on the upper plate located directly above the sample, the axial pressure device presses on the sample, the upper end face of the sample base has a funnel-shaped liquid inlet hole, a height difference between the liquid inlet hole and the porous gasket forms a water-soluble zone, the liquid outlet hole is connected to a dynamic water pressure generator, and a liquid outlet hole is provided on the side wall of the sample sleeve corresponding to the water-soluble zone and the sample base, and the liquid outlet hole is connected to a drain pipe. The device is small, has no large control load, and uses an ingenious mechanical structure design to complete the control of pressure size and change frequency. Compared with ordinary devices, it does not require additional pressure sources such as hydraulic presses and fatigue testing machines, and the device is simple to operate.

Description

Technical Field

[0001] The invention relates to a test device for simulating dynamic water corrosion of road sample materials under load, in particular to a test system for simulating water damage and data acquisition of road materials under different load states using variable-frequency and amplitude-adjustable water pressure, and relates to the fields of traffic engineering and mechanical engineering. Background Art

[0002] Frequent early water damage to asphalt pavements has attracted great attention from road workers, who have invested a lot of manpower, material and financial resources to conduct extensive research on the mechanism, evaluation methods and prevention measures of water damage to asphalt pavements. It is generally believed that the destructive effects of water damage on asphalt pavements can be divided into two aspects: on the one hand, the emulsification and penetration of water into asphalt will cause asphalt to lose its adhesion and peel off from the aggregate surface; on the other hand, the pressure water flow generated by the water in the pavement gap under the action of vehicle load will dissolve and scour the asphalt mixture, causing the asphalt mixture to loosen and lose stability. Although different mechanisms lead to different manifestations of water damage, in reality, both factors work together. Generally speaking, when the asphalt pavement has a good density or strong drainage capacity, it is not easy for water to accumulate inside the pavement, so no excess pore water pressure will be generated. The damage of water to asphalt mixture is mainly reflected in the emulsification of water. When the road surface is seeping but not drained, water will accumulate inside the gaps in the road surface. At this time, under the action of external vehicle loads, excess pore water pressure will be generated, and then dissolution and scouring will occur. At this time, water damage mainly comes from dynamic water dissolution and scouring. In comparison, emulsification can be regarded as the slow deterioration of asphalt mixture by static water, and the damage to asphalt pavement is far less direct and rapid than dynamic water dissolution and scouring. In fact, many engineering practices have shown that most of the early water damage to asphalt pavements belongs to the type of dynamic water dissolution damage. Dynamic water dissolution can greatly accelerate the development of water damage, causing the performance of asphalt mixtures to decline rapidly in a short period of time until it is completely destroyed. Therefore, compared with static water action, dynamic water dissolution has a more obvious acceleration effect on water damage and greater harm, which is also the main reason for the frequent water damage in the early stage of use of many pavements.

[0003] The early damage of pavement caused by dynamic water dissolution has been confirmed by more and more engineering examples. However, the current evaluation method of water damage is still based on tests based on static water conditions, and the impact of dynamic water dissolution on water damage is not considered. In fact, the accelerating effect of dynamic water dissolution cannot be ignored, and in some cases it even plays a leading role. Therefore, it is necessary to conduct more in-depth and detailed research. The water damage evaluation method based on static water tests can no longer meet the development needs of road engineering. However, there is a lack of corresponding research on water sensitivity tests based on dynamic water dissolution in China. It is necessary to propose a new test method based on dynamic water pressure conditions to simulate the development process of water damage to the roadbed and pavement, so as to evaluate the water damage to the roadbed and pavement. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention proposes a load and dynamic water coupled roadbed dissolution and scour simulation system. The device is small, has no large control load, and uses ingenious mechanical structure design to control the pressure size and change frequency. Compared with ordinary devices, it does not require additional pressure sources such as hydraulic presses and fatigue testing machines, and the device is easy to operate.

[0005] The technical solution adopted by the present invention is: a load and dynamic water coupling roadbed dissolution and scour simulation system, comprising: The water damage pressure chamber comprises a base and a pressure frame fixed on the base, an upper plate is fixedly installed on the top of the pressure frame, a sample base is fixedly installed at the center of the base, a sample sleeve is detachably fixedly installed on the sample base, a porous gasket is fixedly installed inside the sample sleeve, an iron net is fixedly installed on the porous gasket, a side wall of the sample sleeve has a plurality of through holes, the height of the through holes is higher than the height of the iron net, a sample with a rubber membrane is placed on the iron net, and the lower end of the rubber membrane is sealed with the side wall of the sample sleeve In coordination, an axial pressure device is fixedly installed on the upper plate located directly above the specimen, and the axial pressure device is pressed on the specimen. A funnel-shaped liquid inlet hole is provided on the upper end face of the specimen base to form a water-soluble area, and the liquid outlet hole is connected to a dynamic water pressure generator. Liquid outlet holes are provided on the side wall of the specimen sleeve and the specimen base corresponding to the water-soluble area, and the liquid outlet holes are connected to a drain pipe. A confining pressure area is formed between the specimen sleeve, the pressure frame, the upper plate, and the base, and the confining pressure area is connected to a confining pressure pipeline. Water is injected into the confining pressure area through the confining pressure pipeline to form the confining pressure of the specimen.

[0006] On the basis of the above scheme, preferably, the axial pressure device includes a sample cap, which is pressed on the test piece, and the upper end of the sample cap is fixedly connected to a force transmission rod, which is connected to a pressure source.

[0007] On the basis of the above solution, preferably, a force measuring ring is installed on the force transmission rod.

[0008] Based on the above solution, preferably, the pressure frame is fixedly connected to the base by bolts.

[0009] On the basis of the above solution, preferably, the specimen sleeve is sleeved on the specimen base, and the upper end of the specimen base is against the porous gasket.

[0010] On the basis of the above scheme, as a preferred embodiment, the dynamic water pressure generator includes a cylinder, a piston is installed in the cylinder, the piston is connected to a driving mechanism that drives it to reciprocate in the cylinder, a solution cavity is formed between the piston and the front end of the cylinder, and the solution cavity is connected to the liquid inlet through a pipeline.

[0011] On the basis of the above scheme, as a preferred embodiment, the dynamic water pressure generator includes a first cylinder and a second cylinder symmetrically fixedly mounted on the base, a first piston is mounted in the first cylinder, the first piston is fixedly connected to the first transmission rod, a first solution cavity is formed between the first piston and the front end of the first cylinder, the first solution cavity is connected to the liquid inlet through a pipeline, a second piston is mounted in the second cylinder, the second piston is fixedly connected to the second transmission rod, a second solution cavity is formed between the second piston and the front end of the second cylinder, and the second solution cavity is connected to the drain pipe, It also includes a driving unit for driving the first piston and the second piston to move synchronously in opposite directions.

[0012] On the basis of the above scheme, as a preference, the driving unit includes a motor, the output shaft of the motor is fixedly connected to the eccentric wheel, the outer ring of the eccentric wheel is connected to the wheel seat through a bearing, the left side of the upper end of the wheel seat is rotatably connected to the first connecting arm, the first connecting arm is rotatably connected to the right end of the bracket, the left end of the bracket is fixedly connected to the first transmission rod, the right end of the bracket is fixedly connected to the second transmission rod, the bracket has a strip-shaped guide hole, the length direction of the guide hole is left and right, the output shaft passes through the guide hole and is fixedly connected to the eccentric wheel, the right side of the lower end of the wheel seat is rotatably connected to the second connecting arm, and the second connecting arm is rotatably connected to the left end of the bracket.

[0013] On the basis of the above scheme, as a preference, the bracket includes a left end plate, a right end plate, a front side plate, and a rear side plate. The left end face of the left end plate is fixedly connected to the first transmission rod, and the right end face of the right end plate is fixedly connected to the second transmission rod. The front side plate and the right side plate are both provided with the guide holes, and the two ends of the first connecting arm and the second connecting arm are rotatably connected to the corresponding wheel seat, front side plate, and rear side plate through pivots, respectively.

[0014] On the basis of the above solution, preferably, the front side plate and the rear side plate are Z-shaped parts.

[0015] Compared with the prior art, the present invention has the following beneficial effects: It can simulate the water in the gaps of the roadbed and pavement under the action of vehicle load, and produce water pressure of dissolution effect on the roadbed and pavement materials. It can produce positive pressure of 0~500kPa. The pressure amplitude can be adjusted and set according to the test road conditions. The maximum frequency of pressure change can be 15Hz, which can basically complete the dynamic water pressure simulation under various road conditions and driving conditions. The test devices are all assembled in modular form, and different modules can be matched according to the use requirements to meet the needs of different pressure sizes and frequencies.

[0016] The device is small, has no large control load, and uses ingenious mechanical structure design to control the pressure size and change frequency. Compared with ordinary devices, it does not require additional pressure sources such as hydraulic presses and fatigue testing machines, and the device is easy to operate.

[0017] The present invention simulates the damage law of road engineering materials (test pieces / roadbed) under dynamic water pressure and clarifies the influence of dynamic water pressure on water damage of road materials. This not only helps to further understand the nature of water damage, but also has important significance for road maintenance and repair, and long-life road structure design, and can also bring good economic and social benefits.

[0018] In the present invention, only one motor is needed to realize the water-soluble circulation experiment of the first cylinder and the second cylinder, and the method is simple, the manufacturing is convenient, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the structure of the specimen hoop; Figure 3 It is a schematic diagram of the structure of the porous gasket and the iron mesh; Figure 4 is a schematic diagram of the structure of the drive unit; Figure 5 is a partial diagram of the drive unit; Figure 6 This is a schematic diagram of the coordination of the eccentric wheel and the wheel seat; Figure 7 It is the actual picture of the specimen before the experiment; Figure 8 This is the actual picture of the specimen after the experiment. DETAILED DESCRIPTION

[0020] The present invention will be further described below by way of examples, but the scope of the present invention is not limited thereto.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0022] like Figure 1-8 As shown, a load and water-dynamic coupling roadbed dissolution and scour simulation system includes: The water damage pressure chamber comprises a base 1 and a pressure frame 2 fixed on the base, an upper plate 3 fixedly installed on the top of the pressure frame, a sample base 4 fixedly installed at the center of the base, a sample sleeve 5 detachably fixedly installed on the sample base, a porous gasket 6 fixedly installed inside the sample sleeve, an iron net 7 fixedly installed on the porous gasket, a side wall of the sample sleeve has a plurality of through holes, the height of the through holes is higher than the height of the iron net, a sample 8 covered with a rubber membrane is placed on the iron net, and the lower end of the rubber membrane is sealed with the side wall of the sample sleeve In coordination, an axial pressure device is fixedly installed on the upper plate located directly above the specimen, and the axial pressure device is pressed on the specimen. The upper end face of the specimen base has a funnel-shaped liquid inlet hole 9 to form a water-soluble area, and the liquid outlet hole is connected to the dynamic water pressure generator. Liquid outlet holes 10 are provided on the side walls of the specimen sleeve and the specimen base corresponding to the water-soluble area, and the liquid outlet holes are connected to a drain pipe 11. A confining pressure area 12 is formed between the specimen sleeve, the pressure frame, the upper plate, and the base, and the confining pressure area is connected to a confining pressure pipeline. Water is injected into the confining pressure area through the confining pressure pipeline 13 to form the confining pressure of the specimen.

[0023] The axial pressure device includes a sample cap 14, which is pressed on the test piece. The upper end of the sample cap is fixedly connected to a force transmission rod 15, which is connected to a pressure source.

[0024] A force ring is installed on the force transmission rod.

[0025] The pressurized frame is fixedly connected to the base via bolts 16 .

[0026] The specimen hoop is sleeved on the specimen base, and the upper end of the specimen base is against the porous gasket.

[0027] The dynamic water pressure generator includes a first cylinder 17 and a second cylinder 18 symmetrically fixedly mounted on a base 19, a first piston is mounted in the first cylinder, the first piston is fixedly connected to a first transmission rod 20, a first solution cavity is formed between the first piston and the front end of the first cylinder, the first solution cavity is connected to the liquid inlet through a pipeline (water inlet pipeline), a second piston is mounted in the second cylinder, the second piston is fixedly connected to a second transmission rod 21, a second solution cavity is formed between the second piston and the front end of the second cylinder, the second solution cavity is connected to a drain pipe, the first transmission rod and the second transmission rod are slidably connected to a first support plate 22 and a second support plate 23 fixed on the base, It also includes a driving unit for driving the first piston and the second piston to move synchronously in opposite directions.

[0028] The driving unit includes a motor 24, the output shaft 25 of the motor is fixedly connected to the eccentric wheel 26, the outer ring of the eccentric wheel is connected to the wheel seat 34 through a bearing, the upper end of the wheel seat is rotatably connected to the first connecting arm 27 on the left side, the first connecting arm is rotatably connected to the right end of the bracket, the left end of the bracket is fixedly connected to the first transmission rod, the right end of the bracket is fixedly connected to the second transmission rod, the bracket has a strip-shaped guide hole, the length direction of the guide hole is the left and right direction, the output shaft passes through the guide hole 33 and is fixedly connected to the eccentric wheel, the lower end of the wheel seat is rotatably connected to the second connecting arm 28 on the right side, and the second connecting arm is rotatably connected to the left end of the bracket.

[0029] The bracket includes a left end plate 29, a right end plate 30, a front side plate 31, and a rear side plate 32. The left end surface of the left end plate is fixedly connected to the first transmission rod, and the right end surface of the right end plate is fixedly connected to the second transmission rod. The front side plate and the right side plate are both provided with the guide holes, and the two ends of the first connecting arm and the second connecting arm are rotatably connected to the corresponding wheel seat, front side plate, and rear side plate through pivots.

[0030] Among them, the front side plate and the rear side plate are Z-shaped parts.

[0031] The water inlet pipe and the drainage pipe are installed with constant pressure valves. Through the regulation of the constant pressure valve, when the water pressure generated by the dynamic water pressure generator is too large, the water pressure is adjusted.

[0032] The water loss pressure chamber is the main structure of the dynamic water dissolution system, which is mainly responsible for providing access to the water environment of dynamic water dissolution and other environmental conditions.

[0033] The dynamic water pressure in the test is connected through the water inlet pipe under the pressure chamber and directly acts on the center of the bottom of the specimen. After the dissolution water flows out through the dynamic water pressure input pipe, it will first pass through the porous gasket and iron net at the bottom of the specimen. Under the action of the gasket and iron net, the water flow of the secondary water distribution will disperse and evenly dissolve the specimen. The combination of different gaskets can also simulate the fixed-point dissolution and the emptying of the specimen caused by long-term dissolution. The water loss pressure chamber provides a simulation environment for confining pressure water injection. The main body is made of materials including but not limited to plexiglass and steel structure.

[0034] The confining pressure in the test is input through the confining pressure pipeline to simulate the surrounding pressure of the foundation under real road conditions. The confining pressure loading adopts hydraulic pressurization with a maximum pressure of 2MPa. The pressurizing equipment is connected to the bottom of the pressure chamber through a water pipe. When working, the stepper motor in the confining pressure equipment drives the piston to inject water into the pressure chamber, and stops and maintains when the preset pressure is reached.

[0035] The force transfer rod transfers the axial pressure to the pressure cap on the top of the specimen to complete the axial pressure loading of the specimen. The maximum axial pressure is 50kN.

[0036] The axial pressure can be achieved by installing a drive such as a cylinder on the upper plate to drive the force transmission rod to press down, or by threading the force transmission rod and the upper plate to change the pressure by rotating upward or downward.

[0037] The control system includes hardware and software and data acquisition. The hardware part is mainly responsible for the power supply of the equipment and the external port. The software part is the control panel of the confining pressure, axial pressure and dynamic water pressure generator, which is responsible for the setting, loading, unloading, control and data acquisition of axial pressure and confining pressure. The confining pressure and axial pressure control includes parameter setting and status display and base control button. The parameter setting includes the basic information input of the specimen, the input of axial pressure and confining pressure value, the input of axial pressure loading speed and the limited axial displacement, which respectively control the target axial pressure and confining pressure size, and the axial pressure loading speed limit. The status display includes the actual axial pressure rate, confining pressure value, axial force and axial displacement, which is the actual value display of the corresponding items in the parameter setting. The dynamic water pressure generator control includes pressure display, dynamic water pressure setting and control button. The pressure display is a real-time display of the output pressure value generated by the dynamic water pressure generator. The dynamic water pressure setting includes motor speed setting, pressure setting, sampling frequency setting and serial port selection setting, which is the target setting value of the dynamic water pressure generator. The control button is a button for controlling the operation of the device, which is mainly for the start and stop control of the motor and the acquisition control of each sensor.

[0038] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A load and water-dynamic coupling roadbed erosion and scour simulation system, characterized in that: include: The water damage pressure chamber comprises a base and a pressure frame fixed on the base, an upper plate is fixedly installed on the top of the pressure frame, a sample base is fixed at the center of the base, a sample sleeve is detachably fixedly installed on the sample base, a porous gasket is fixedly installed inside the sample sleeve, an iron net is fixedly installed on the porous gasket, a side wall of the sample sleeve has a plurality of through holes, the height of the through holes is higher than the height of the iron net, a sample with a rubber membrane is placed on the iron net, and the lower end of the rubber membrane is sealed with the side wall of the sample sleeve, and is located directly above the sample An axial pressure device is fixedly installed on the upper plate of the square, and the axial pressure device is pressed on the specimen. A funnel-shaped liquid inlet hole is provided on the upper end surface of the specimen base. A height difference between the liquid inlet hole and the porous gasket forms a water-soluble area. The liquid outlet hole is connected to a dynamic water pressure generator. Liquid outlet holes are provided on the side wall of the specimen sleeve and the specimen base corresponding to the water-soluble area. The liquid outlet holes are connected to a drain pipe. A confining pressure area is formed between the specimen sleeve, the pressure frame, the upper plate and the base. The confining pressure area is connected to a confining pressure pipeline, and water is injected into the confining pressure area through the confining pressure pipeline to form the confining pressure of the specimen.

2. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 1 is characterized in that: The axial pressure device comprises a sample cap, which is pressed on the test piece. The upper end of the sample cap is fixedly connected to a force transmission rod, which is connected to a pressure source.

3. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 1 is characterized in that: A force ring is installed on the force transmission rod.

4. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 1 is characterized in that: The pressurized frame is fixedly connected to the base through bolts.

5. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 1 is characterized in that: The specimen hoop is sleeved on the specimen base, and the upper end of the specimen base is against the porous gasket.

6. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 1 is characterized in that: The dynamic water pressure generator comprises a first cylinder and a second cylinder symmetrically fixedly mounted on a base, a first piston is mounted in the first cylinder, the first piston is fixedly connected to a first transmission rod, a first solution cavity is formed between the first piston and the front end of the first cylinder, the first solution cavity is connected to a liquid inlet through a pipeline, a second piston is mounted in the second cylinder, the second piston is fixedly connected to a second transmission rod, a second solution cavity is formed between the second piston and the front end of the second cylinder, and the second solution cavity is connected to a drain pipe, It also includes a driving unit for driving the first piston and the second piston to move synchronously in opposite directions.

7. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 6 is characterized in that: The driving unit includes a motor, the output shaft of the motor is fixedly connected to the eccentric wheel, the outer ring of the eccentric wheel is connected to the wheel seat through a bearing, the left side of the upper end of the wheel seat is rotatably connected to the first connecting arm, the first connecting arm is rotatably connected to the right end of the bracket, the left end of the bracket is fixedly connected to the first transmission rod, the right end of the bracket is fixedly connected to the second transmission rod, the bracket is provided with a strip-shaped guide hole, the length direction of the guide hole is the left and right direction, the output shaft passes through the guide hole and is fixedly connected to the eccentric wheel, the right side of the lower end of the wheel seat is rotatably connected to the second connecting arm, and the second connecting arm is rotatably connected to the left end of the bracket.

8. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 7 is characterized in that: The bracket includes a left end plate, a right end plate, a front side plate, and a rear side plate. The left end surface of the left end plate is fixedly connected to the first transmission rod, and the right end surface of the right end plate is fixedly connected to the second transmission rod. The front side plate and the right side plate are both provided with the guide holes, and the two ends of the first connecting arm and the second connecting arm are rotatably connected to the corresponding wheel seat, front side plate, and rear side plate through pivots.

9. The load and water dynamic coupling roadbed erosion and scour simulation system according to claim 8, characterized in that: The front side plate and the rear side plate are Z-shaped parts.

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