CN113252470A - Road surface interlaminar shearing scale simulation device - Google Patents
Road surface interlaminar shearing scale simulation device Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
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- G01B5/02—Measuring arrangements characterised by the use of mechanical techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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Abstract
The invention relates to a pavement interlayer shearing scale simulation device which comprises a supporting platform and a mechanical body, wherein the mechanical body comprises a shearing box for bearing a test piece, a normal stress loading unit for simulating the pressure contact state of a vehicle tire and a pavement, a horizontal tension and pressure control unit for simulating the applied shearing force and a displacement measurement unit for measuring shearing test data, the shearing box comprises an upper shearing box and a lower shearing box which are arranged in a laminated mode and respectively bear a surface layer test piece and a base layer test piece, the lower shearing box is fixed on the supporting platform, the normal stress loading unit is arranged above the upper shearing box and vertically acts on the upper surface of the surface layer test piece, and the horizontal tension and pressure control unit and the displacement measurement unit are respectively arranged on two opposite side faces of the upper shearing box and are respectively connected with the upper shearing box. Compared with the prior art, the invention can realize comprehensive, efficient and accurate measurement of the shearing resistance between the road surface layers, so as to facilitate the refinement and the scientization of indoor tests and on-site road surface detection.
Description
Technical Field
The invention relates to the technical field of road engineering, in particular to a road surface interlayer shearing scale simulation device.
Background
As a main pavement form of a highway in China, the asphalt pavement is frequently damaged early along with the increase of traffic volume, serious overload phenomenon and the like in recent years. The core drilling result at the later stage shows that the bonding effect between the surface layer and the base layer of a part of asphalt pavement is poor, the whole shear resistance of the pavement structure is insufficient, and the direct reason for pavement damage is caused. The interlayer adhesion state of the asphalt pavement has an important effect on the stability and durability of the whole pavement structure, and therefore it is necessary to study the interlayer shear strength of the asphalt pavement.
The method for evaluating the interlayer shear strength is mainly based on a direct shear test and an oblique shear test, wherein the oblique shear test is to place a surface layer and a base layer into a test mold, apply normal stress to the top of the test mold, and decompose the normal stress and the shear stress on a shear surface with a certain angle, so that a test piece is subjected to shear failure, the oblique shear test can better simulate an interface shear state, but has the problems of large size, fixed shear angle and the like, and the obtained test result cannot well reflect the bonding performance of a bonding layer. The direct shear test is based on a molar-coulomb strength theory, a horizontal shear force is applied to a test piece along a fixed shear surface under different normal stresses, the maximum shear stress when the test piece is damaged is taken as the shear strength of the test piece, the direct shear test is taken as an important test for evaluating the friction shear strength of an interface in the field of highway geotechnical tests, and the direct shear test is simple to operate, strong in adaptability, short in test time and the like and is widely adopted.
The existing direct shearing means mainly comprises a horizontal direct shearing mode and a vertical direct shearing mode, wherein the vertical direct shearing mode is mainly characterized in that a target test piece is transversely placed, and then normal stress is applied to the side surface part of an upper surface layer. The invention patent CN106596292A discloses a shearing test device between pavement material layers, and the invention patent CN110542618A discloses a direct shearing test method for shearing strength between layers of emulsified asphalt surface treatment layers, and both adopt a vertical direct shearing mode. And adopt horizontal direct shear then can avoid above-mentioned problem, test device pushes and pulls the shearing box under vertical pressure, and this actual shearing direction and the stress state that also better accords with bituminous paving records shearing data through level to displacement sensor and force transducer to obtain the biggest shear stress of limit, experimental easy operation. Therefore, it is necessary to invent a horizontal direct shearing device between pavement material layers.
But the current level direct shear device in China still carries out the upgrading based on traditional geotechnological direct shear appearance and reforms transform, has following problem:
1) pressure action and contact pattern not conforming to reality
The vertical pressure loading mode of the existing direct shear device is mainly that single-point type counter-force pressurization is carried out through a lever principle and the like, and the pressurization point is single and cannot simulate the action effect of a front axle and a rear axle of a vehicle load; and most of the existing direct shear devices carry out single-point concentrated pressurization on vertical stress, certain constraint conditions exist, and the pressure action mode of the vehicle tire and the pavement surface layer material cannot be simulated.
2) Poor shear simulation effect
When the asphalt pavement is subjected to shearing action, the asphalt pavement firstly acts on a surface layer material, then the shearing resistance of an interlayer material resists the shearing force, and the current test means mainly obtains the interlayer shearing stress by pulling and pushing a base layer part of a test piece, so that the obtained maximum shearing stress data has certain error with the shearing fatigue performance.
3) Lack of shear fatigue testing function
The existing direct shear test device can only apply unidirectional horizontal shear force, so that the maximum shear stress data can only be measured, and the shear fatigue performance of a pavement interlayer material under the action of an overlying load cannot be tested.
4) The effect of the device scale is not expected
The existing interlaminar shearing device still needs to be improved in the simulation of the pavement interlaminar shearing mode and the shearing fatigue performance, the consideration on the aspects of the test piece size, the load loading size, the loading mode and the like is not thorough, the shearing performance of the interlaminar material is emphasized, and the measurement of the shearing performance of the interlaminar material in a pavement structure still needs to be improved.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a road surface interlayer shearing scale simulation device.
The purpose of the invention can be realized by the following technical scheme:
a road surface interlayer shearing scale simulation device comprises a supporting platform and a mechanical body arranged on the supporting platform, the machine body comprises a shear box for bearing a test piece, a normal stress loading unit for simulating the pressure contact state of a vehicle tire and a road surface, a horizontal tension and pressure control unit for simulating the application of shear force and a displacement measuring unit for measuring shear test data, the shearing box comprises an upper shearing box and a lower shearing box which are arranged in a laminated manner and respectively bear the surface layer test piece and the base layer test piece, the lower shearing box is fixed on the supporting platform, the normal stress loading unit is arranged above the upper shearing box and vertically acts on the upper surface of the surface layer test piece, the horizontal pulling pressure control unit and the displacement measuring unit are respectively arranged on two opposite side surfaces of the upper shearing box and are connected with the upper shearing box.
Preferably, the normal stress loading unit comprises a counter force mechanism, a jack assembly, a magnetic attraction plate, a force transmission plate and a force transmission wheel assembly, the jack assembly is fixed on the force transmission plate through the magnetic attraction plate, the top of the jack is fixed with the supporting platform through the counter force mechanism, and the force transmission wheel assembly is arranged at the bottom of the force transmission plate.
Preferably, the jack components are arranged into 2 groups, the 2 groups of jack components are sequentially arranged along the transmission direction of the shearing force, each group of jack components is respectively fixed with the supporting platform through a counter force mechanism, correspondingly, the force transmission wheel components are arranged into 2 groups and respectively correspondingly arranged at the positions below the two groups of jack components.
Preferably, the jack assembly comprises a jack, a vertical pressure sensor and a centering device, wherein the vertical pressure sensor is arranged at the bottom of the jack and connected to the centering device, and the centering device is arranged on the magnetic suction plate.
Preferably, the counter force mechanism comprises a door-shaped counter force frame, the door-shaped counter force frame comprises a horizontal counter force rod and two vertical supporting rods, the horizontal counter force rod is erected above the jack assembly, two ends of the horizontal counter force rod are respectively supported and fixed through the vertical supporting rods, the bottoms of the vertical supporting rods are anchored with the supporting platform, a circular groove is formed in the center line of the horizontal counter force rod, and the circular groove is used for being fixed with the top of the jack assembly to form a counter force loading point.
Preferably, the force transmission wheel assembly comprises force transmission wheels used for simulating wheels on two sides of the vehicle, the force transmission wheels are hinged with the force transmission plates through triangular wheel shafts, each force transmission wheel comprises a steel wheel hub and a rubber wheel bead, and the steel wheel hubs and the rubber wheel beads are tightly attached.
Preferably, the front end and the rear end of the upper shear box are respectively provided with a front end convex part and a rear end convex part which are connected with the horizontal tension and pressure control unit and the displacement measuring unit, the front end convex part is provided with an external thread which is used for being connected with the horizontal tension and pressure control unit, and the rear end convex part is provided with a circular groove which is used for being connected with the displacement measuring unit.
Preferably, the horizontal tension pressure control unit comprises a tension press, a connecting piece and a tension pressure sensor, the head end of the connecting piece is connected with the tension press, the tail end of the connecting piece is provided with a circular groove and matched with the sensing front end of the tension pressure sensor, the rear end of the tension pressure sensor is provided with a circular groove, and the circular groove is internally provided with an internal thread matched with the external thread of the front end convex piece of the upper shearing box.
Preferably, the displacement measuring unit comprises a linear displacement sensor, a dial indicator, a 360-degree rotatable holding mechanism and a fixing rod, the linear displacement sensor and the dial indicator are both fixed on the 360-degree rotatable holding mechanism, the linear displacement sensor and the dial indicator are matched with the circular groove on the protruding piece at the rear end of the shearing box in a tip end manner, and the 360-degree rotatable holding mechanism is fixed on the supporting platform through the fixing rod.
Preferably, the drawing and pressing machine comprises a stepless speed change drawing and pressing machine.
Compared with the prior art, the invention has the following advantages:
(1) the road surface interlayer shearing scale simulation device provided by the invention simulates a loading mode and a constraint condition under a real wheel-road surface coupling effect, not only can measure the maximum shearing stress of an interlayer material, but also can measure the shearing fatigue performance of the road surface interlayer, and realizes comprehensive, efficient and accurate measurement of the shearing resistance performance of the road surface interlayer, so that an indoor test and a field road surface detection are facilitated;
(2) according to the invention, the free contact between the tire and the road surface is realized through the front and rear groups of force transmission wheel assemblies, the constraint condition of the traditional device is eliminated, the real pressure contact state of the tire load and the road surface is better simulated through a tire scale reducing method, the load distribution of the front and rear shafts is controlled through the two groups of jacks and the pressure sensors, the actual stress state of the road surface can be accurately met, the arrangement of the force transmission wheels can also simulate the active fatigue shearing action of the vehicle tire through pushing and pulling the upper shearing box, the effective exchange of a reference system is realized, and the actual shearing mode of the road surface structure is met;
(3) the invention can realize the conversion of displacement measurement modes (a linear displacement sensor measurement mode and a dial indicator measurement mode) by arranging the 360-degree rotatable clamping mechanism, and avoids the error caused by single measurement.
Drawings
Fig. 1 is a schematic view of the overall structure of a pavement interlayer shearing scale simulation device.
Fig. 2 is a schematic structural diagram of the main device in fig. 1.
Fig. 3 is a schematic structural diagram of a normal stress loading unit according to the present invention.
Fig. 4 is a schematic view of the construction of the shear box of the present invention.
Fig. 5 is a schematic diagram of the force applied to the direct shear sample of the present invention.
In the figure: 1 is a supporting frame; 2 is a test platform; 3 is a stepless speed change drawing press; 4-1 is a first vertical supporting rod; 4-2 is a second vertical supporting rod; 5-1 is a first welding end; 5-2 is a second welding end; 6-1 is a first anchoring end; 6-2 is a second anchoring end; 7 is a connecting piece; 8 is a pull pressure sensor; 9 is a front end convex part; 10 is an upper cutting box; 11 is a lower cutting box; 12-1 is a first jack; 12-2 is a second jack; 13-1 is a first vertical pressure sensor; 13-2 is a second vertical pressure sensor; 14-1 is a first centering device; 14-2 is a second centering device; 15 is a magnetic attraction plate; 16 is a force transmission plate; 17 is a force transmission wheel component; 18 is a linear displacement sensor; 19 is a dial indicator; 20 is a 360-degree rotatable clamping mechanism; 21 is a brake bolt; 22 is a fixing rod; 23 is a rear end convex part; 24 is a computer; 25 is a first horizontal reaction bar; 26 is a wheel axle; 27 is a power transmission wheel; 28 is U-shaped steel; and 29 is a bolt and nut assembly.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. Note that the following description of the embodiments is merely a substantial example, and the present invention is not intended to be limited to the application or the use thereof, and is not limited to the following embodiments.
Examples
As shown in fig. 1 to 4, the present embodiment provides a road surface interlayer shearing scale simulation apparatus, which includes a supporting platform and a mechanical body disposed on the supporting platform, wherein the supporting platform includes a supporting rack 1 and a testing platform 2. The machine body comprises a shearing box for bearing a test piece, a normal stress loading unit for simulating the pressure contact state of a vehicle tire and a road surface, a horizontal tension and pressure control unit for simulating the application of shearing force and a displacement measuring unit for measuring shearing test data.
The horizontal pulling pressure control unit comprises a stepless speed change pulling press machine 3, a connecting piece 7 and a pulling pressure sensor 8, the normal stress loading unit comprises a counterforce mechanism, a first jack 12-1, a second jack 12-2, a first vertical pressure sensor 13-1, a second vertical pressure sensor 13-2, a first centering device 14-1, a second centering device 14-2, a magnetic attraction plate 15, a force transmission plate 16 and a force transmission wheel assembly 17, the shearing box comprises an upper shearing box 10 and a lower shearing box 11, and the displacement measuring device comprises a linear displacement sensor 18, a dial indicator 19, a 360-degree rotatable clamping mechanism 20 and a fixing rod 22. The supporting platform comprises a supporting frame 1 and a test platform 2.
The stepless speed change drawing and pressing machine 3 is loaded by a Japan loosing servo motor, and the technical parameters are as follows. Maximum shear load: 2.0X 105kN; shear load resolution: 1N; shear load resolution precision: better than plus or minus 0.5 percent; shear loading rate: the thickness is adjustable from 0mm/min to 100 mm/min; shear loading rate control accuracy: 0.5 percent; shear displacement measurement range: 0-150 mm; shear displacement measurement resolution: 0.01 mm; shear displacement measurement accuracy: plus or minus 0.5 percent. The shearing rate and the precision thereof are realized by a variable frequency speed regulation technology under the control of a PLC, and unidirectional shearing force can be applied by inputting direct current or bidirectional fatigue shearing force can be applied by inputting sine type current.
The reaction mechanism is divided into a first reaction mechanism and a second reaction mechanism according to the distance from the continuously variable pull press machine 3. The two groups of counter-force mechanisms have the same structure and function and comprise a counter-force frame and an anchoring end. The first reaction force mechanism will be described below as an example. The reaction frame comprises a first horizontal reaction rod 25 and a first vertical support rod 4-1, the two rods form a first welding end 5-1 with a fixed 90-degree angle in an internal welding mode, preferably, the first welding end 5-1 is formed into a rectangular block through casting, physical polishing and the like, and the rectangular block is provided with two round ends which are perpendicular to each other and used for protecting testers; preferably, a circular groove is arranged at the center line of the first horizontal reaction rod 25 and is used as a reaction force loading point of the first jack 12-1; the first anchoring end 6-1 is composed of a U-shaped steel 28 and a bolt and nut assembly 29 which are symmetrical left and right, preferably, the upper part and the lower part of the U-shaped steel 28 respectively comprise a large round hole and 4 small round holes, and the round holes of the upper part and the lower part are vertically aligned; the first vertical support bar passes through the upper and lower large circular holes of the U-shaped steel, and the bolt and nut assembly 29 passes through the upper and lower small circular holes of the U-shaped steel and is screwed at the bottom to ensure the structural strength of the first vertical support bar 4-1. The second reaction mechanism is the same as the first reaction mechanism.
The tail end of the connecting piece 7 is provided with a circular shallow groove and is matched with the sensing front end of the tension and pressure sensor 8, and the connecting piece and the sensing front end are fixedly connected through embedding so as to ensure that the shearing force is effectively transmitted; the rear end of the pull pressure sensor 8 is also provided with a circular groove, and the groove is internally provided with threads. Preferably, the pull pressure sensor 8 in the present embodiment is a resistance strain gauge diaphragm pressure sensor.
The upper shearing box 10 is provided with through holes at the upper and lower parts, and the side surface is provided with a front end convex part 9 and a rear end convex part 23; the front end convex part 9 is cylindrical, and the surface of the front end convex part is also provided with threads matched with the rear end groove of the pulling pressure sensor 8; the rear end convex part 23 is cylindrical, the surface is smooth, and the bottom surface is provided with a circular groove; the front end convex part 9 is connected with the pull pressure sensor 23 through screw threads in a screwing mode and is used for fixing the position of the applied shearing force. Preferably, the physical parameters of the upper shear box 10 are as follows. According to the principle of geometric similarity, determining the internal geometric dimension: 150mm × 150mm × 40 mm; external (without front and rear end projections) geometry: 200 mm. times.200 mm. times.45 mm. The upper part of the lower shearing box 11 is provided with an opening, the bottom surface is a rectangular steel sheet and is matched with the upper shearing box 10; the lower shearing box 11 is fixedly embedded with the test platform 2 and is kept still all the time in the test process, so that the measured relative displacement data is guaranteed to be effective and accurate. Preferably, the physical parameters of the lower shear box 11 are as follows. According to the principle of geometric similarity, determining the internal geometric dimension: 150mm × 150mm × 90 mm; external geometry: 200mm by 100 mm.
The technical parameters of the first jack 12-1 and the second jack 12-2 are as follows: maximum vertical load: 1.0X 105kN; vertical load resolution: 1N; vertical load resolution precision: better than plus or minus 0.5 percent. The first jack 12-1 and the second jack 12-2 are respectively arranged on the first vertical pressure sensor 13-1 and the second vertical pressure sensor 13-2, and the first vertical pressure sensor 13-1 and the second vertical pressure sensor 13-2 are respectively arranged on the first centering device 14-1 and the second centering device 14-2. The center lines of the first jack 12-1, the first vertical pressure sensor 13-1 and the first centralizer 14-1 are superposed; the center lines of the second jack 12-2, the second vertical pressure sensor 13-2 and the second centralizer 14-2 are coincided. The first centering device 14-1 and the second centering device 14-2 are arranged in two limiting clamping grooves at the geometric center of the magnetic suction plate 15, and the inner dimensions of the limiting clamping grooves are matched with the sizes of the first centering device 14-1 and the second centering device 14-2. The magnetic suction plate 15 is tightly connected with the lower-covering force transfer plate 16 under the action of magnetic attraction and is used for redistributing the upper vertical load. Preferably, the first vertical pressure sensor in the present embodimentThe device 13-1 and the second vertical pressure sensor 13-2 both adopt resistance strain type diaphragm pressure sensors.
Further, the force transmission wheel assembly 17 is hinged with the force transmission plate 16 through a triangular wheel shaft 26, and the triangular wheel shaft 26 is welded and fixed with the force transmission plate 16; the force transmission wheel assemblies 17 comprise a front group and a rear group, each group of force transmission wheel assemblies respectively comprises a left shaft and a right shaft and is a single-shaft double-wheel assembly; the single transfer wheel 27 comprises a steel hub and a rubber wheel bead, with the two abutting. Preferably, the physical parameters of the single power wheel 27 are as follows. According to the principle of physical similarity, determining the inner diameter d of the steel hub130mm, outside diameter D132 mm; rubber wheel bead d232mm, outside diameter D235mm and a steel radial tire was used.
Further, the tips of the linear displacement sensor 18 and the dial indicator 19 are matched with the circular groove in the rear end convex part 23 and just contact the bottom of the groove, so that the measured shearing displacement is accurate; the linear displacement sensor 18 is fixed with a 360-degree rotatable clamping mechanism 20 through two vertical bolts; the dial indicator 19 is fixed with a 360-degree rotatable clamping mechanism 20 through a single bolt; the extension part of the 360-degree rotatable clamping mechanism 20 comprises a circular hole matched with the fixed part, the tail end of the 360-degree rotatable clamping mechanism 20 is provided with threads and is connected with a fixed rod 22 through a brake bolt 21, and automatic displacement measurement and manual reading conversion can be realized by means of the loosening clamping mechanism 20 of the brake bolt 21. The fixing bar 22 is anchored with the test platform 2 and keeps the fixing bar 22 perpendicular to the test platform 2.
In the embodiment, the linear displacement sensor 18 utilizes conductive plastics and a sliding brush to directly measure the displacement of the rear-end convex part 23, and the two ends of the linear displacement sensor 18 are provided with flexible bearings, so that the linear displacement sensor can play an effective buffering role and can be used for measuring the maximum shearing stress between layers and controlling the maximum displacement of shearing fatigue; the dial indicator 19 is a clock type dial indicator and is only used for measuring the maximum shearing stress between layers, and the technical parameters are as follows. The measuring range of the large pointer is 0-10mm, and the division value is 0.01 mm; the small pointer range is 0-50mm, and the division value is 10 mm; the total measuring range is 0-50 mm; the precision is better than +/-0.2%.
Preferably, 2 front ends of test platform still are equipped with the thing groove of putting that can hold infinitely variable speed and draw the press, and the thing groove of putting comprises the rectangular plate of the difference of front and back height, and the thing groove width slightly is greater than and draws the required width of press normal work for prevent to cause the influence to the experiment because of the unstable vibration that produces of electric current, and put thing groove bottom and be equipped with the step in order to guarantee that the shearing force applies in the middle part of last shearing box.
The test steps of the invention are as follows:
firstly, preparing a test piece, namely rolling and forming the test piece by using a wheel rolling forming machine, wherein the size of a surface layer test piece is 150mm multiplied by 40mm, and the size of a base layer test piece is 150mm multiplied by 90mm according to the principle of geometric similarity. After the test piece is formed, coating adhesive layer oil on the surface of the base test piece, wherein the using amount of the adhesive layer oil refers to the spraying amount recommended by technical Specification for construction of asphalt pavement for roads, and 1.5kg/m is taken2As an upper limit of the specification value. And after coating the sticky layer oil, standing for 5min, bonding the bottom surface of the asphalt mixture surface layer test piece with the coating surface of the base layer test piece, and after bonding, placing the test piece for 5min to ensure the formation of the sticky layer oil strength.
Secondly, coating a proper amount of lubricating oil in the upper shearing box 10 and the lower shearing box 11, then placing the prepared composite test piece into the lower shearing box 11, and adjusting the position of the test piece to ensure that the side wall of the lower layer test piece of the tested composite test piece is contacted and abutted with the inner side wall of the lower shearing box 11; then, the upper shear box 10 is placed on the lower shear box 11, and the upper shear box 10 is adjusted to ensure that the side wall of the upper test piece of the tested composite test piece is in contact with and abutted against the inner side wall of the upper shear box 10.
And thirdly, fixing the tension and pressure sensor 8, the linear displacement sensor 18 and the dial indicator 19, and enabling the tension and pressure sensor, the linear displacement sensor 18 and the dial indicator 19 to be in a free telescopic state.
Sequentially placing the normal stress loading units above the test piece from bottom to top, and adjusting the vertical pressure sensors 13-1 and 13-2 to test zero values, namely corrected initial values such as dead weights of the centralizers 14-1 and 14-2, the force transfer plate 16 and the force transfer wheel assembly 17; after the operation is finished, controlling the normal pressure value of the bottom of the loaded tire to be 0.7MPa, and performing load redistribution by adjusting the counter-force loading size of the first jack 12-1 and the second jack 12-2 according to the adopted standard shaft type, wherein according to the physical similarity principle, the load ratio adopts a front shaft: rear axle 1:2, etc.
And fifthly, switching on the power supply, correcting the initial values of the pull pressure sensor 8, the linear displacement sensor 18 and the dial indicator 19 to be zero, and testing whether the connection between each sensor and the data acquisition computer 24 is good.
After confirming that no error exists, if the maximum shearing stress between the layers is measured, the stepless speed change tension and compression machine 3 is set to be in a one-way shearing stress applying mode, the shearing rate required by the test is selected, then the data acquisition computer 24 is opened, the tension and compression machine 3 is started, the test is carried out, and the shearing stress and the displacement data are acquired; if the interlaminar fatigue shearing performance is measured, the stepless speed change drawing and pressing machine 3 is set to be in a bidirectional drawing and pressing shearing mode, namely sinusoidal current is input, the shearing rate and the single shearing displacement limit value required by the test are set, then the data acquisition computer 24 is opened, the drawing and pressing machine 3 is started, the test is carried out, and data such as shearing stress, displacement, fatigue shearing times and the like are acquired.
And seventhly, closing the stepless speed change drawing and pressing machine 3 and each data acquisition device after the test is finished.
The invention has the advantages that: the device simulates a loading mode and constraint conditions under the real vehicle-road coupling action, not only can measure the maximum shearing stress of the interlayer material, but also can measure the interlayer shearing fatigue performance of the pavement. The device realizes free contact between the tire and the road surface through the front and rear groups of force transmission wheel assemblies, eliminates the constraint condition of the traditional device, better simulates the real contact state between the tire load and the road surface through a tire scale reducing method, controls the load distribution of the front and rear shafts through the two groups of jacks and the pressure sensor, and can accurately accord with the axle load loading mode of the road surface in China. And the arrangement of the power transmission wheel can simulate the active fatigue shearing action of the vehicle tire by pushing and pulling the upper shearing box, so that the effective exchange of the reference system is realized, and the actual shearing mode of the road surface is met. In addition, the 360-degree rotatable clamping mechanism can realize the conversion of displacement measurement modes, and the error caused by single measurement is avoided. Comprehensive, efficient and accurate measurement of the shearing resistance between the road surface layers can be realized through the device, so that the indoor test and the field road surface detection are refined and scientific.
FIG. 5 is a schematic diagram of the force applied to the direct shear specimen of the present invention, wherein T is the shear stress applied by the horizontal tension/pressure control unit, P11、P12、P21、P22Normal stress applied for normal stress loading unit, wherein P11、P12Are in a group, can be adjusted synchronously, P21、P22The adjustment can be synchronized, and delta is the displacement.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the following descriptions are only illustrative and not restrictive, and the scope of the present invention is not limited thereto: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A road surface interlayer shearing scale simulation device is characterized by comprising a supporting platform and a mechanical body arranged on the supporting platform, the machine body comprises a shear box for bearing a test piece, a normal stress loading unit for simulating the pressure contact state of a vehicle tire and a road surface, a horizontal tension and pressure control unit for simulating the application of shear force and a displacement measuring unit for measuring shear test data, the shear box comprises an upper shear box (10) and a lower shear box (11) which are arranged in a laminated manner and respectively bear the surface layer test piece and the base layer test piece, the lower shearing box (11) is fixed on the supporting platform, the normal stress loading unit is arranged above the upper shearing box (10) and vertically acts on the upper surface of the surface test piece, the horizontal pulling pressure control unit and the displacement measuring unit are respectively arranged on two opposite side surfaces of the upper shearing box (10) and are connected with the upper shearing box (10).
2. The device for simulating shearing shrinkage of pavement layers according to claim 1, wherein the normal stress loading unit comprises a counterforce mechanism, a jack assembly, a magnetic suction plate (15), a force transfer plate (16) and a force transfer wheel assembly (17), the jack assembly is fixed on the force transfer plate (16) through the magnetic suction plate (15), the top of the jack is fixed with the supporting platform through the counterforce mechanism, and the force transfer wheel assembly (17) is arranged at the bottom of the force transfer plate (16).
3. The device for simulating shearing shrinkage of pavement layers according to claim 2, wherein 2 sets of jack assemblies are provided, the 2 sets of jack assemblies are sequentially arranged along the shearing force transmission direction, each set of jack assemblies is respectively fixed with the supporting platform through a counterforce mechanism, and correspondingly, the 2 sets of force transmission wheel assemblies (17) are respectively and correspondingly arranged at positions below the two sets of jack assemblies.
4. The pavement interlayer shear scale simulation device according to claim 3, wherein the jack assembly comprises a jack, a vertical pressure sensor and a centering device, the bottom of the jack is provided with the vertical pressure sensor and is connected to the centering device, and the centering device is installed on the magnetic suction plate (15).
5. The device of claim 3, wherein the reaction mechanism comprises a door-shaped reaction frame, the door-shaped reaction frame comprises a horizontal reaction rod and two vertical support rods, the horizontal reaction rod is erected above the jack assembly, two ends of the horizontal reaction rod are supported and fixed through the vertical support rods respectively, the bottoms of the vertical support rods are anchored with the supporting platform, a circular groove is formed in the center line of the horizontal reaction rod, and the circular groove is used for forming a reaction force loading point with the top of the jack assembly.
6. A road surface interlaminar shear scale simulator according to claim 3, wherein said force transfer wheel assembly (17) comprises force transfer wheels (27) for simulating the wheels on both sides of the vehicle, said force transfer wheels (27) being hingedly connected to said force transfer plate (16) by means of triangular wheel axles (26), said force transfer wheels (27) comprising a steel hub and a rubber wheel bead, said steel hub and rubber wheel bead being in close proximity to each other.
7. The road surface interlaminar shear scale simulation device according to claim 1, wherein the front and rear ends of the upper shear box (10) are respectively provided with a front end convex member (9) and a rear end convex member which are connected with the horizontal tension and pressure control unit and the displacement measuring unit, the front end convex member (9) is provided with an external thread for connecting with the horizontal tension and pressure control unit, and the rear end convex member is provided with a circular groove for connecting with the displacement measuring unit.
8. The device for simulating the shearing shrinkage of the pavement layers as claimed in claim 7, wherein the horizontal pulling and pressing force control unit comprises a pulling and pressing machine, a connecting piece (7) and a pulling and pressing force sensor (8), the head end of the connecting piece (7) is connected with the pulling and pressing machine, the tail end of the connecting piece (7) is provided with a circular groove and is matched with the sensing front end of the pulling and pressing force sensor (8), the rear end of the pulling and pressing force sensor (8) is provided with a circular groove, and the circular groove is internally provided with an internal thread matched with the external thread of the front end convex piece (9) of the upper shearing box (10).
9. The pavement interlayer shearing scale simulating device as recited in claim 7, wherein the displacement measuring unit comprises a linear displacement sensor (18), a dial indicator (19), a 360 ° rotatable holding mechanism (20) and a fixing rod (22), the linear displacement sensor (18) and the dial indicator (19) are both fixed on the 360 ° rotatable holding mechanism (20), the tips of the linear displacement sensor (18) and the dial indicator (19) are adapted to be matched with a circular groove on a convex member at the rear end of the shearing box (10), and the 360 ° rotatable holding mechanism (20) is fixed on the supporting platform through the fixing rod (22).
10. The device for simulating road surface interlaminar shear shrinkage according to claim 8, wherein the drawing and pressing machine comprises a continuously variable drawing and pressing machine (3).
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| CN202110412170.0A CN113252470A (en) | 2021-04-16 | 2021-04-16 | Road surface interlaminar shearing scale simulation device |
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| CN202110412170.0A CN113252470A (en) | 2021-04-16 | 2021-04-16 | Road surface interlaminar shearing scale simulation device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113984546A (en) * | 2021-09-28 | 2022-01-28 | 北京建筑大学 | Testing machine and testing method for measuring road interlayer shear strength |
| CN114002079A (en) * | 2021-11-08 | 2022-02-01 | 江苏科技大学 | Large-scale interface shearing equipment and implementation method thereof |
| CN114166658A (en) * | 2021-12-07 | 2022-03-11 | 长沙学院 | Method for testing shearing characteristic of vertical interface between waste tire and soil |
| CN116026711A (en) * | 2023-03-30 | 2023-04-28 | 江苏腾达工程检测有限公司 | Asphalt pavement shearing fatigue degree detection equipment |
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2021
- 2021-04-16 CN CN202110412170.0A patent/CN113252470A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113984546A (en) * | 2021-09-28 | 2022-01-28 | 北京建筑大学 | Testing machine and testing method for measuring road interlayer shear strength |
| CN113984546B (en) * | 2021-09-28 | 2023-08-22 | 北京建筑大学 | Testing machine and testing method for measuring road interlayer shear strength |
| CN114002079A (en) * | 2021-11-08 | 2022-02-01 | 江苏科技大学 | Large-scale interface shearing equipment and implementation method thereof |
| CN114166658A (en) * | 2021-12-07 | 2022-03-11 | 长沙学院 | Method for testing shearing characteristic of vertical interface between waste tire and soil |
| CN114166658B (en) * | 2021-12-07 | 2024-04-12 | 长沙学院 | Method for testing shear characteristics of vertical interface of junked tire and soil |
| CN116026711A (en) * | 2023-03-30 | 2023-04-28 | 江苏腾达工程检测有限公司 | Asphalt pavement shearing fatigue degree detection equipment |
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