Multi-directional coupling pavement loading test device and method based on dynamic triaxial apparatus
By integrating hydraulic loading and impact loading systems, and combining electromagnets with free-fall hammers, a realistic simulation of multi-directional loads is achieved, overcoming the shortcomings of traditional equipment and providing an efficient means of testing the stress on road materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENAN UNIV OF SCI & TECH
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies cannot accurately reproduce the coupling effect of multi-directional loads, especially high-energy instantaneous impact loads. Furthermore, traditional loading equipment systems are complex, have poor coordination, and are costly.
It adopts an integrated hydraulic loading system and an innovative impact loading system, combined with an electromagnet and a free-fall hammer, to achieve the coupled application of axial creep, lateral dynamic disturbance and vertical instantaneous impact load, and to precisely control the impact energy and timing through electronic control.
It achieves a realistic simulation of road surface materials under complex stress conditions, significantly increases the impact force, has a reasonable structural design, is easy to operate, and provides accurate and reliable test data.
Smart Images
Figure CN122016633A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of road engineering testing technology, and in particular to a multi-directional coupled road surface loading test device and method based on a dynamic triaxial apparatus. Background Technology
[0002] With the increasing traffic volume and rising vehicle axle loads, road surfaces are subjected to complex multi-directional coupled loads in actual use. These loads mainly include: axial creep stress generated in the forward direction of the road due to long-term vehicle travel; dynamic disturbance stress generated on both sides of the road due to the interaction of adjacent roads or traffic flows; and instantaneous impact loads generated by road surface unevenness during vehicle travel. Traditional road material performance testing equipment, such as dynamic triaxial apparatus, can simulate axial cyclic loads and lateral disturbance loads relatively well, but it is difficult to realistically reproduce the coupled effects of the above-mentioned multi-directional loads, especially in terms of effectively simulating high-energy instantaneous impact loads.
[0003] In existing technologies, some scholars have attempted to achieve multi-directional loading by combining different loading devices, but this approach suffers from problems such as system complexity, poor coordination between loading systems, and high costs. Especially in impact load simulation, traditional free-fall hammers rely solely on gravitational potential energy, resulting in limited impact force and difficulty in precisely controlling impact energy and timing, thus failing to meet the simulation requirements for heavy vehicle impact loads. Therefore, developing a test device that integrates axial creep, lateral disturbance, and controllable high-energy impact loading is of great significance for in-depth research into the mechanical response and failure mechanism of pavement materials under real complex stress states. Summary of the Invention
[0004] To address the difficulties in simulating multi-directional load coupling and the problems of insufficient and uncontrollable impact energy in the prior art, this invention proposes a multi-directional coupled road loading test device and method based on a dynamic triaxial apparatus. The technical solution adopted by this invention is as follows: A multi-directional coupled road loading test device based on a dynamic triaxial apparatus includes a sample testing device, a sample fixing device, a hydraulic loading device, and an impact loading device. The sample testing device includes a computer, a strain gauge, a force sensor, and an impact control system. The strain gauge contains a strain meter. The computer is connected to the strain gauge, force sensor, and impact control system via a data cable, and the strain gauge is connected to the strain meter via a signal cable, forming a data acquisition and control system. The sample fixing device includes a double-layer steel table, a sample box, and a confining steel plate. The double-layer steel table is tightly welded and fixed to the ground with anchor bolts. The sample box is fixed to the upper surface of the double-layer steel table with bolts. The sample box is a five-sided tightly welded steel box structure with circular through holes on the front, top, bottom, left, and right sides, while the rear remains intact. The confining steel plate is fixed to the rear of the sample box with prestressed bolts. A road sample is installed inside the sample box, and a strain meter is pre-embedded inside the road sample. The hydraulic loading device includes an upper hydraulic cylinder, a lower hydraulic cylinder, a left hydraulic cylinder, a right hydraulic cylinder, and a hydraulic system. The upper and lower hydraulic cylinders are connected by the upper and lower layers of the double-layer steel table. The corresponding through holes and the through holes on the triangular steel bracket correspond to the upper and lower surfaces of the sample box; the left and right hydraulic cylinders correspond to the left and right sides of the sample box via the triangular steel brackets; the triangular steel brackets are tightly welded and fixed to the ground on both sides of the double-layer steel table with anchor bolts; the trapezoidal steel plates on the left, right, and upper sides have holes corresponding to the through holes of the sample box for bolting the hydraulic cylinders; the hydraulic system is located in the space below the double-layer steel table and is connected to the inlet and outlet ports of each hydraulic cylinder via high-pressure oil pipes; the impact loading device includes a rectangular steel bracket and an electric hoist. The system consists of a controller, a suspension steel pipe, an impact hammer, and an electromagnet. A rectangular steel support frame is tightly welded to the ground on both sides of the double-layer steel table via anchor bolts, positioned at the same horizontal level in front of the sample chamber. The suspension steel pipe is connected to the rectangular steel support frame via a hinge. The impact hammer is welded to the end of the suspension steel pipe, and its bottom is equipped with a strongly bonded rubber buffer pad. The electromagnet is fixed to the top of the sample chamber via bolts on an adjustable support steel pipe, which is tightly welded to the rectangular steel support frame. The impact control system is welded to the rectangular steel support frame and connected to the electromagnet via a cable.
[0005] As a further optimization of the above-mentioned multi-directional coupled road loading test device based on a dynamic triaxial apparatus, the double-layer steel table adopts a channel steel welded frame structure. The upper table surface is provided with positioning holes corresponding to the through holes of the sample box, and the lower frame is provided with hydraulic cylinder mounting and fixing holes, which are fixed by bolts.
[0006] As a further optimization of the aforementioned multi-directional coupled road loading test device based on a dynamic triaxial apparatus, the hydraulic system includes an oil tank, a control valve group, an electro-hydraulic servo controller, and oil inlets and outlets. It can independently or by computer control the output force, loading rate, and pressure holding time of the four hydraulic cylinders (up, down, left, and right).
[0007] As a further optimization of the above-mentioned multi-directional coupled road loading test device based on a dynamic triaxial apparatus, the triangular steel bracket has a welded stable structure, and trapezoidal steel plates are provided on the left, right and upper sides with hydraulic cylinder mounting holes, which are fixed by bolts. The trapezoidal steel plates are welded to the triangular steel bracket.
[0008] As a further optimization of the aforementioned multi-directional coupled road loading test device based on a dynamic triaxial apparatus, the impact control system includes a programmable controller, a high-power DC power supply, and a relay switch; the magnetic force is controlled by adjusting the excitation current and energizing time of the electromagnet, and the impact height is adjusted by controlling the swing angle of the suspended steel pipe, thereby achieving precise control of the impact energy.
[0009] A test method based on a multi-directional coupled road loading test device using a dynamic triaxial apparatus includes the following steps: Step 1: Sample preparation and installation. Place the road surface sample with pre-embedded strain gauges into the sample box and fix the sample box to the upper layer of the double-layer steel table with bolts, ensuring that all through holes are aligned. Step 2: Hydraulic system connection and debugging. Connect the hydraulic system to the oil circuits of each hydraulic cylinder. Perform no-load debugging of the hydraulic system through computer control and check whether the operation of each hydraulic cylinder is normal. Step 3: Impact system preparation. The suspended steel pipe is swung to a predetermined angle through the impact control system, the position of the electromagnet is adjusted, and the impact parameters are set. Step 4: System calibration. Connect the computer, strain gauge, force sensor, and strain gauge with wires to perform sensor zero-point calibration and signal testing. Step 5: Multi-directional coupling loading test. First, start the hydraulic system and apply axial creep load and lateral disturbance load according to the preset program; then trigger the impact control system at the predetermined time. The electromagnet is first energized to attract the impact hammer. At the moment of impact, the power is cut off and the hammer is released, completing the impact loading. Step Six: Data Acquisition and Analysis. Test data is acquired in real time using strain gauges and force sensors, transmitted to a computer for processing, and load-time curves and strain-time curves are plotted. Step 7: Test termination and data processing. Once the preset test termination conditions are met, stop loading, organize the test data, and analyze the mechanical response characteristics of the pavement material under multi-directional coupled loads.
[0010] As a further optimization of the test method of the above-mentioned multi-directional coupled pavement loading test device based on a dynamic triaxial apparatus, the pavement specimen is an asphalt mixture cylindrical specimen or a cement concrete cubic specimen.
[0011] As a further optimization of the test method of the above-mentioned multi-directional coupled road loading test device based on a dynamic triaxial apparatus, the strain gauge is a dynamic resistance strain gauge with a sampling frequency of not less than 1kHz; the force sensor is a spoke-type force sensor with a range of 0-50kn.
[0012] Beneficial effects Compared with the prior art, the present invention has significant advantages and beneficial effects, achieving considerable technological progress and practicality, and possessing broad application value. It has at least the following advantages: 1. This invention integrates a hydraulic loading system and an innovative impact loading system, enabling the simultaneous application of three loads—axial creep, lateral dynamic disturbance, and vertical instantaneous impact—on a single device, thus realistically simulating the complex stress state of the road surface in actual use.
[0013] 2. The impact loading system of the present invention combines electromagnetism with free-falling hammer to achieve the combination of gravitational potential energy and electromagnetic energy absorption, which significantly increases the impact force, solves the problem of insufficient impact energy of traditional falling hammer, and achieves precise control of impact energy and timing through electronic control.
[0014] 3. The device has a reasonable structural design. The double-layer steel table and triangular steel bracket provide stable support. The sample box is easy to install and replace samples. Each system is highly modular, easy to operate, and the test data is accurate and reliable. Attached Figure Description
[0015] Figure 1 This is a three-dimensional structural schematic diagram of the experimental device of the present invention; Figure 2 This is a schematic diagram of the sample fixing device of the present invention; Figure 3 This is a schematic diagram of the structure of the sample of the present invention; Figure 4 This is a schematic diagram of the sample loading device of the present invention; Figure 5 This is a schematic diagram of the triangular steel support structure for the sample of the present invention; Figure 6 This is a schematic diagram of the sample impact loading device of the present invention; Figure 7 This is a schematic diagram of the supporting steel pipe structure of the present invention; Figure 8 This is a schematic diagram of the impact hammer of the present invention; Figure 9 A schematic diagram of the hydraulic system of this invention.
[0016] In the diagram: 1. Computer; 2. Strain gauge; 3. Force sensor; 4. Impact control system; 5. Strain gauge; 6. Double-layer steel table; 7. Sample box; 8. Confining steel plate; 9. Road surface sample; 10. Upper hydraulic cylinder; 11. Lower hydraulic cylinder; 12. Left hydraulic cylinder; 13. Right hydraulic cylinder; 14. Rectangular steel bracket; 15. Trapezoidal steel plate; 16. Hydraulic system; 161. Oil tank; 162. Control valve group; 17. High-pressure oil pipe; 18. Inlet and outlet oil ports; 19. Triangular steel bracket; 20. Suspension steel pipe; 21. Impact hammer; 22. Electromagnet; 23. Hinge connection; 24. Rubber buffer pad; 25. Supporting steel pipe; 26. Prestressed bolt; 27. Mounting fixing hole; 28. Electric hoist controller. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments and accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of protection. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art, without creative effort, including formal modifications to the technical solutions described in the following embodiments or equivalent substitutions of some technical features, based on the inspiration of the present invention, are within the scope of protection of the present invention.
[0018] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0019] Example 1: As Figure 1-8 As shown, a multi-directional coupled road loading test device based on a dynamic triaxial apparatus mainly consists of four parts: a sample testing device, a sample fixing device, a hydraulic loading device, and an impact loading device.
[0020] The core of the sample testing device is the computer 1, which is connected to the strain gauge 2, force sensor 3, and strain gauge 5 pre-embedded in the road surface sample 9 via wires. The hydraulic system 16 and impact control system 4 are also connected to the computer 1 via data lines, receiving unified control from it and providing feedback on status information, thus forming an intelligent testing system that integrates control, loading, measurement, data acquisition, and analysis.
[0021] In the sample fixing device, the double-layer steel table 6 is fixed to the ground with anchor bolts, providing a stable foundation. The sample box 7 is welded from high-strength steel plates, with circular through holes at the center of its four sides. The rear panel remains intact and is fitted with confining steel plates 8 connected by prestressed bolts 26 to simulate the rigid support of the roadbed. The road surface sample 9 is tightly installed inside the sample box 7.
[0022] The hydraulic loading device is crucial for simulating axial and lateral loads. The triangular steel bracket 14 is tightly welded and fixed to the ground on both sides of the double-layer steel table 6 using anchor bolts. The upper hydraulic cylinder 10 and lower hydraulic cylinder 11 are fixed to the double-layer steel table 6 and the trapezoidal steel plate 15 above the triangular steel bracket 19 using corresponding bolt holes, respectively, aligning with the upper and lower through holes of the sample chamber 7. The left hydraulic cylinder 12 and right hydraulic cylinder 13 are fixed to the left and right through holes of the left and right steel plates of the triangular steel bracket 19 using bolt holes, aligning with the left and right through holes of the sample chamber 7. The hydraulic system 16 is located in the space below the double-layer steel table 6. Its oil tank 161 and control valve group 162 are connected to the inlet and outlet ports of the four hydraulic cylinders via high-pressure oil pipes 17. Through programming with the computer 1, the output (pressure) and movement speed (flow rate) of each hydraulic cylinder can be independently controlled, thereby achieving constant creep loading in the vertical direction and dynamic disturbance loading in the horizontal direction.
[0023] The impact loading device simulates vehicle impact loads. A rectangular steel bracket 14 is tightly welded to the ground of the double-layer steel table 6 using anchor bolts. A suspension steel pipe 20 is connected to the top of the rectangular steel bracket 14 via a hinge 23, allowing it to swing like a pendulum. An impact hammer 21 is tightly adhered to the bottom rubber buffer pad 24 and welded to the suspension steel rod 20. An electromagnet 22 is bolted to an adjustable support steel pipe 25, which is welded to the rectangular steel bracket 14 and positioned at the same level as the front of the sample chamber. The impact control system 4 includes a controller, a high-power power supply, and switching circuits; its controller communicates with the computer 1.
[0024] During the test, axial and lateral loads were first applied through the hydraulic system 16 to simulate the basic stress state of the road surface. Then, the impact loading program was initiated: the impact control system 4 controlled the electric hoist controller 28 to swing the suspension steel pipe 20, which suspends the impact hammer 21, to a predetermined angle (height H). Under the command of the computer 1, the electromagnet 22 was energized, generating a strong magnetic attraction force. The impact hammer 21, under the combined action of gravitational acceleration and the additional acceleration brought by the electromagnetic force, swung at high speed toward and impacted the front surface of the road surface sample. The power supply to the electromagnet was cut off one second before impact.
[0025] Throughout the experiment, data from various sensors were recorded and analyzed in real time by computer 1, thereby comprehensively evaluating the mechanical properties and damage evolution of the pavement samples under multi-directional coupled loads.
[0026] Example 2: The road surface sample 9 is made of cement concrete, and its preparation and curing must comply with relevant specifications. During the test, the range of hydraulic loading force and the energy level of the impact load need to be appropriately adjusted according to the material properties of the concrete.
[0027] Example 3: The controller of the impact system 4 integrates a high-speed data acquisition card, which can simultaneously record the data of the electromagnet current cut-off moment, the impact contact moment, and the strain gauge, thereby more accurately analyzing the time history curve of the impact force and the dynamic response of the material.
[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A multi-directional coupled road loading test device based on a dynamic triaxial apparatus, characterized in that: The system includes a sample testing device, a sample fixing device, a hydraulic loading device, and an impact loading device. The sample testing device includes a computer (1), a strain gauge (2), a force sensor (3), and an impact control system (4). The strain gauge (2) contains a strain gauge (5). The computer (1) is connected to the strain gauge (2), the force sensor (3), and the impact control system (4) via a data cable. The strain gauge (2) is connected to the strain gauge (5) via a signal cable, forming a complete data acquisition and control system. The sample fixing device includes a double-layer steel table (6), a sample box (7), and a confining steel plate (8). The double-layer steel table (6) is tightly welded and fixed to the ground with anchor bolts. The sample box (7) is fixed to the double-layer steel table with bolts. (6) The upper platform; the sample box (7) is a steel box structure with five sides tightly welded, with circular through holes on the front, top, bottom, left and right sides, and the back is intact; the confining steel plate (8) is fixed to the back of the sample box (7) by prestressed bolts (27); the road sample (9) is installed in the sample box (7), and the road sample (9) is pre-embedded with strain gauges (5); the hydraulic loading device includes an upper hydraulic cylinder (10), a lower hydraulic cylinder (11), a left hydraulic cylinder (12), a right hydraulic cylinder (13) and a hydraulic system (16); the upper hydraulic cylinder (10) and the lower hydraulic cylinder (11) are connected to the sample through the corresponding through holes on the upper and lower layers of the double-layer steel table (6) and the through holes on the upper part of the triangular steel bracket (19). The upper and lower surfaces of the box body (7) correspond to each other; the left hydraulic cylinder (12) and the right hydraulic cylinder (13) correspond to the left and right sides of the sample box body (7) through the triangular steel bracket (19); the triangular steel bracket (19) is tightly welded and fixed to the ground on both sides of the double-layer steel table (6) by anchor bolts, and the trapezoidal steel plates (15) set on its left, right and upper sides are provided with holes corresponding to the through holes of the sample box body (7) for bolt fixing of the hydraulic cylinders; the hydraulic system (16) is set in the space below the double-layer steel table (6) and is connected to the inlet and outlet ports (18) of each hydraulic cylinder through the high-pressure oil pipe (17); the impact loading device includes a rectangular steel bracket (14), an electric hoist controller (28), a suspension steel pipe (20), and an impact hammer (21). The rectangular steel bracket (14) is tightly welded to the ground on both sides of the double-layer steel table (6) by anchor bolts and is located on the same horizontal plane in front of the sample box (7); the suspension steel pipe (20) is connected to the rectangular steel bracket (14) by hinge (23); the impact hammer (21) is welded to the end of the suspension steel pipe (20) and its bottom is provided with a strong adhesive rubber buffer pad (24); the electromagnet (22) is fixed to the top of the sample box (7) by bolts through the adjustable support steel pipe (25), the adjustable support steel pipe (25) is tightly welded to the rectangular steel bracket (14), and the impact control system (4) is welded to the rectangular steel bracket (14) and connected to the electromagnet (22) by cable.
2. The multi-directional coupled road loading test device based on a dynamic triaxial apparatus as described in claim 1, characterized in that: The double-layer steel table (6) adopts a channel steel welded frame structure. The upper table surface has positioning holes corresponding to the through holes of the sample box (7), and the lower frame has hydraulic cylinder mounting and fixing holes, which are fixed by bolts.
3. The multi-directional coupled road loading test device based on a dynamic triaxial apparatus as described in claim 1, characterized in that: The hydraulic system (16) includes an oil tank (161), a control valve group and an electro-hydraulic servo controller (162), and an oil inlet and outlet (163). It can independently or by computer control the output, loading rate and pressure holding time of the four hydraulic cylinders (up, down, left, and right).
4. The multi-directional coupled road loading test device based on a dynamic triaxial apparatus as described in claim 1, characterized in that: The triangular steel bracket (19) is welded to a stable structure, and trapezoidal steel plates (15) are provided on the left, right and upper sides, and hydraulic cylinder mounting holes (27) are opened. The trapezoidal steel plates are welded to the triangular steel bracket (19) by bolts.
5. The multi-directional coupled road loading test device based on a dynamic triaxial apparatus as described in claim 1, characterized in that: The impact control system (4) includes a programmable controller, a high-power DC power supply and a relay switch; the magnitude of the magnetic force is controlled by adjusting the excitation current and energizing time of the electromagnet (22), and the impact height is adjusted by controlling the swing angle of the suspended steel pipe (20), thereby achieving precise control of the impact energy.
6. A test method for a multi-directional coupled road surface loading test apparatus based on any one of claims 1 to 5, characterized in that: Includes the following steps, Step 1: Sample preparation and installation. Place the road surface sample (9) with pre-embedded strain gauges (5) into the sample box (7). Fix the sample box (7) to the upper layer of the double-layer steel table (6) with bolts to ensure that all through holes are aligned. Step 2: Hydraulic system connection and debugging. Connect the hydraulic system (16) to the oil circuit of each hydraulic cylinder. Control the hydraulic system (16) through the computer (1) to perform no-load debugging and check whether the operation of each hydraulic cylinder is normal. Step 3: Impact system preparation. The suspended steel pipe (20) is swung to a predetermined angle by the impact control system (4), the position of the electromagnet (22) is adjusted, and the impact parameters are set. Step 4: System calibration. Connect the computer (1), strain gauge (2), force sensor (3), and strain gauge (5) with wires to perform sensor zero-point calibration and signal testing. Step 5: Multi-directional coupling loading test. First, start the hydraulic system (16) and apply axial creep load and lateral disturbance load according to the preset program; then trigger the impact control system (4) at the predetermined time. The electromagnet (22) is energized to attract the impact hammer (21). At the moment of impact, the power is cut off and released to complete the impact loading. Step 6: Data acquisition and analysis. Experimental data is acquired in real time through strain gauges (5) and force sensors (3), and transmitted to computer (1) for processing to plot load-time curves and strain-time curves. Step 7: Test termination and data processing. Once the preset test termination conditions are met, stop loading, organize the test data, and analyze the mechanical response characteristics of the pavement material under multi-directional coupled loads.
7. The test method of a multi-directional coupled road surface loading test device based on a dynamic triaxial apparatus as described in claim 6, characterized in that: The road surface specimen (9) is an asphalt mixture cylindrical specimen or a cement concrete cubic specimen.
8. The test method of a multi-directional coupled road loading test device based on a dynamic triaxial apparatus as described in claim 6, characterized in that: The strain gauge (2) is a dynamic resistance strain gauge with a sampling frequency of not less than 1kHz; the force sensor (3) is a spoke-type force sensor with a range of 0-50kΩ.