CN115711822A

CN115711822A - Impact test device capable of adjusting confining pressure and impact test method

Info

Publication number: CN115711822A
Application number: CN202211411025.1A
Authority: CN
Inventors: 陈成; 朱思凡; 汤语嫣; 贾西贝
Original assignee: Institute Of Advanced Research Wuhan University Of Technology Shangyu District Shaoxing City
Current assignee: Institute Of Advanced Research Wuhan University Of Technology Shangyu District Shaoxing City
Priority date: 2022-11-11
Filing date: 2022-11-11
Publication date: 2023-02-24

Abstract

The invention discloses an impact test device capable of adjusting confining pressure.A base is provided with stand columns, cross beams are arranged between the stand columns, and height adjusting structures for adjusting the heights of the cross beams are arranged on the stand columns; the beam is provided with an impact loading mechanism; be provided with confined pressure control mechanism on the base, confined pressure control mechanism is including placing the housing on the base, and the inside of housing is provided with a plurality of gasbag, is provided with the baffle between the adjacent gasbag, and the inside of gasbag is provided with the sample, the upper and lower surface contact of sample and gasbag, and the gasbag is connected with the confined pressure controller through independent gas tube, is provided with the control valve that the control gas tube opened or closed on the gas tube. The invention also discloses an impact test method of the impact test device capable of adjusting confining pressure. By adopting the impact test device and the impact test method capable of adjusting confining pressure, the invention can solve the problem that the existing impact test device can not simultaneously research the impact conditions of the railway ballast under different confining pressure conditions.

Description

Impact test device capable of adjusting confining pressure and impact test method

Technical Field

The invention relates to the technical field of impact tests, in particular to an impact test device capable of adjusting confining pressure and an impact test method.

Background

Railway transportation is an important transportation mode, and plays a vital role in economic and civil development. Along with the rapid development of railway trains in China, the high-speed and heavy-load of the trains puts forward higher new requirements on the sleepers. A ballast track bed belongs to a discrete body structure, generally consists of high-strength and low-weathering-degree sharp-angled particles, and plays roles in dispersing and transferring load, buffering vibration and draining water in the track structure. In the operation process of a train, due to the mechanical characteristics of the bulk particles of the railway ballast, the railway ballast can move, rotate and rearrange under the action of external load, so that the phenomena of deterioration such as sleeper sinking, slurry pumping, railway bed hardening and the like are caused, and the geometric shape and position of the railway are difficult to maintain. When the train wheel passes through the uneven track surface, the wheel tread is separated from the top surface of the steel rail, and because a series of springs of the vehicle bogie are in a compressed state, when the wheel is separated, the compression springs bounce the wheel to the track surface, so that the impact of the wheel rail is caused, and the track bed is degraded. At approach bridges, switches or other track transitions, the wheel-rail interface can produce high downward impact forces due to abrupt changes in track stiffness. Therefore, the research on the degradation of the ballast bed of the railway ballast caused by the impact load has important significance for ensuring the safe operation of the train.

The traditional impact test can only research the impact condition of the ballast under a single confining pressure. However, in the actual engineering situation, the cross section of the track bed is trapezoidal, the confining pressure of the ballast from top to bottom is gradually increased along with the depth change of the track bed, and the traditional impact test device cannot reach the sample confining pressure in the actual situation.

Disclosure of Invention

The invention aims to provide an impact test device capable of adjusting confining pressure, and solves the problem that the existing impact test device cannot simultaneously research the impact conditions of railway ballasts under different confining pressure conditions. The invention further aims to provide an impact test method of the impact test device with the adjustable confining pressure.

In order to achieve the purpose, the invention provides an impact test device capable of adjusting confining pressure, which comprises a base, wherein stand columns are arranged on the base, a cross beam is arranged between the stand columns, and a height adjusting structure for adjusting the height of the cross beam is arranged on each stand column; the beam is provided with an impact loading mechanism; be provided with confining pressure control mechanism on the base, confining pressure control mechanism is located the crossbeam under, confining pressure control mechanism is including placing the housing on the base, and the inside of housing is provided with a plurality of gasbag, is provided with the baffle of restriction gasbag axial deformation between the adjacent gasbag, and the inside of gasbag is provided with the sample, the upper and lower surface contact of sample and gasbag, and the gasbag is connected with the confining pressure controller through independent gas filling pipe, is provided with the control valve that the control gas filling pipe opened or closed on the gas filling pipe.

Preferably, the height adjusting structure comprises adjusting holes, the stand column is provided with a plurality of adjusting holes arranged along the length direction of the stand column, and the bolt penetrates through the adjusting holes to realize the fixed connection of the cross beam and the stand column.

Preferably, the housing is a transparent acrylic shell, and the air bag is a transparent air-rib film.

Preferably, the confining pressure controller is provided with a pressurizing knob for controlling the gas circuit to be switched on or off, a pressure gauge for setting target confining pressure, a pressure adjusting knob for adjusting the pressure of the pressure gauge, and an electronic back pressure gauge for displaying the pressure in the gas bag.

Preferably, the impact loading mechanism comprises a drop hammer and a guide rod, a through hole for the guide rod to pass through is formed in the cross beam, the guide rod is connected with the cross beam in a sliding manner, the drop hammer is sleeved on the guide rod and is connected with the guide rod in a sliding manner, the drop hammer is positioned right above the center of the air bag, a limiting block for limiting the drop hammer to slip from the guide rod is arranged at the bottom end of the guide rod, a cover plate is arranged right below the guide rod, the bottom end of the guide rod is in contact with the cover plate, and the cover plate is covered right above the air bag and is positioned in the cover shell; the upright post is provided with a power structure for driving the drop hammer to slide on the guide rod.

Preferably, the power structure includes the pulley, and the pulley rotates and sets up on the stand, and the guide pulley that sets up on the crossbeam is walked around to the one end of the wire rope of winding on the pulley is connected with the drop hammer.

The impact test method of the impact test device based on the adjustable confining pressure comprises the following steps:

s1, placing air bags and a partition plate in an aligned mode, sleeving a cover on the outer portions of the air bags, and connecting a gas filling pipe on each air bag to a confining pressure controller;

s2, rotating a pressure adjusting knob to enable a pointer on a pressure gauge to reach a target confining pressure required by a corresponding air bag, opening a pressurizing knob and a control valve on an air adding pipe, inflating and pressurizing the air bag, displaying the pressure in the air bag on an electronic counter-pressure gauge in real time until the pressure on the electronic counter-pressure gauge reaches the confining pressure set by the pressure gauge, and closing the pressurizing knob and the control valve to enable the confining pressure in the air bag to be maintained at the set confining pressure;

s3, repeating the step S2 to enable the confining pressure in each air bag to reach the corresponding set confining pressure;

s4, adjusting the position of the cross beam on the stand column so as to adjust the height of the cross beam, rotating the pulley, winding the steel wire rope, driving the drop hammer to move upwards by the steel wire rope, and lifting the drop hammer to a certain height; the pulley is loosened, the drop hammer falls freely, the drop hammer transmits impact force to the sample in the air bag through the limiting block and the cover plate on the guide rod, and impact load is applied to the sample;

and S5, observing the displacement and the breakage of the sample through the transparent cover and the air bag.

The impact test device and the impact test method capable of adjusting confining pressure have the advantages and positive effects that:

1. be provided with the regulation hole on the stand, can adjust the height of crossbeam through selecting different regulation holes to the height of adjustment drop hammer, and then carry out the impact test under the different impact load to the sample.

2. The hammer that falls is established on the guide bar, and the guide bar bottom is provided with the stopper, and the gasbag top is provided with the apron, and the hammer that falls passes through stopper and apron will strike the more even sample of acting on in the gasbag of load, improves impact test's accuracy.

3. The device is provided with a plurality of independent air bags, and the air bags are filled with air with different pressures, so that the confining pressure of samples at different depths under the actual working condition is simulated, and the research on the linear confining pressure boundary condition of the ballast samples is realized.

4. The impact test device can also be used for loading tests of rock soil materials such as soil, calcareous sand and the like.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic perspective view of an embodiment of an impact test apparatus and an impact test method with adjustable confining pressure according to the present invention;

fig. 2 is a schematic diagram of a connection structure of an airbag and a confining pressure controller according to an embodiment of an impact test apparatus and an impact test method capable of adjusting confining pressure.

Reference numerals

1. A base; 2. a column; 3. a cross beam; 4. dropping a hammer; 5. a guide bar; 6. a limiting block; 7. a cover plate; 8. a housing; 9. an air bag; 10. a partition plate; 11. a sample; 12. a pulley; 13. a confining pressure controller; 14. air adding pipe; 15. a control valve; 16. a pressurizing knob; 17. a pressure gauge; 18. a pressure adjusting knob; 19. an electronic back pressure gauge; 20. and adjusting the hole.

Detailed Description

The technical scheme of the invention is further explained by the attached drawings and the embodiment.

Unless defined otherwise, technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

Examples

Fig. 1 is a schematic perspective view of an impact test apparatus and an impact test method according to an embodiment of the invention, and fig. 2 is a schematic view of a connection structure of an airbag and a confining pressure controller according to an embodiment of an impact test apparatus and an impact test method according to an embodiment of the invention. As shown in the figure, the impact test device capable of adjusting confining pressure comprises a base 1, wherein the base 1 is fixed on the ground. Be provided with stand 2 on the base 1, two vertical fixed settings of stand 2 are on base 1. The bottom end of the upright post 2 is fixed on the base 1 through a bolt. Be provided with crossbeam 3 between the stand 2, be provided with the altitude mixture control structure of adjusting crossbeam 3 height on the stand 2. The height adjusting structure comprises adjusting holes 20, the adjusting holes 20 are formed in the upright post 2 and are formed in a plurality of the upright post 2 along the length direction, and the bolts penetrate through the adjusting holes 20 to fixedly connect the cross beam 3 and the upright post 2. Through selecting different regulation holes 20, the height of crossbeam 3 can be adjusted as required to satisfy the impact test under the different heights.

And a confining pressure control mechanism is arranged on the base 1 and is positioned under the cross beam 3. Confining pressure control mechanism is including placing housing 8 on base 1, and housing 8 is transparent ya keli shell, is convenient for observe the impact test condition in the housing 8. The cover 8 can limit the radial deformation of the bladder 9. A plurality of air bags 9 are arranged in the housing 8, samples 11 are arranged in the air bags 9, and the air bags 9 are transparent air-rib type films, so that the states of the samples 11 in the air bags 9 can be observed conveniently. In the embodiment, 5 air bags 9 are arranged, and the air bags 9 are filled with certain pressure to set the confining pressure for the sample 11, so that the confining pressures of the samples 11 at different depths can be accurately simulated.

A partition plate 10 for limiting the axial deformation of the air bags 9 is arranged between the adjacent air bags 9, and the test sample 11 is contacted with the upper surface and the lower surface of the air bags 9. The air bag 9 is connected with a confining pressure controller 13 through an independent air adding pipe 14, and a control valve 15 for controlling the opening or closing of the air adding pipe 14 is arranged on the air adding pipe 14. The independent setting of 5 gasbag 9 can set for different confining pressure for different gasbag 9 as required to the impact test condition of different degree of depth samples 11 under the simulation operating condition improves the accuracy of railway ballast impact test simulation.

The confining pressure controller 13 is provided with a pressurizing knob 16 for controlling the gas circuit to be opened or closed, a pressure gauge 17 for setting target confining pressure, a pressure adjusting knob 18 for adjusting the size of the pressure gauge 17, and an electronic counter-pressure gauge 19 for displaying the pressure in the air bag 9. Each air bag 9 is independently corresponding to a set of pressurizing knob 16, a pressure gauge 17, a pressure adjusting knob 18 and an electronic counter-pressure gauge 19, so that different confining pressures can be independently set for each air bag 9. The pressurizing knob 16, the pressure gauge 17, the pressure adjusting knob 18 and the electronic counter-pressure gauge 19 all adopt the existing structures.

The beam 3 is provided with an impact loading mechanism. The impact loading mechanism comprises a drop hammer 4 and a guide rod 5, a through hole for the guide rod 5 to penetrate through is formed in the cross beam 3, and the guide rod 5 is connected with the cross beam 3 in a sliding mode. The drop hammer 4 is sleeved on the guide rod 5 and is in sliding connection with the guide rod 5, the guide rod 5 has a guiding effect on the drop of the drop hammer 4, and the drop hammer 4 is prevented from deviating when falling. The drop hammer 4 is positioned right above the center of the air bag 9, and the bottom end of the guide rod 5 is provided with a limiting block 6 for limiting the drop hammer 4 to slip off from the guide rod 5.

A cover plate 7 is arranged right below the guide rod 5, the bottom end of the guide rod 5 is in contact with the cover plate 7, and the cover plate 7 is covered on the airbag 9 and is positioned in the cover case 8. After the drop hammer 4 falls down, the impact force is transmitted to the cover plate 7 through the limiting block 6, the cover plate 7 uniformly applies the impact force to the sample 11, and the effect and accuracy of impacting the sample 11 are prevented from being influenced due to too much concentration of the impact force of the drop hammer 4.

The upright post 2 is provided with a power structure for driving the drop hammer 4 to slide on the guide rod 5. The power structure comprises a pulley 12, the pulley 12 is rotatably arranged on the upright post 2, and one end of a steel wire rope wound on the pulley 12 is connected with the drop hammer 4 by bypassing a guide wheel arranged on the cross beam 3. The drop weight 4 is lifted to a certain height by the pulley 12 and the wire rope, and then the drop weight 4 is allowed to freely fall, thereby giving an impact to the test piece 11.

s1, placing the air bags 9 in alignment with the partition plates 10, sleeving the outer portions of the air bags 9 with a cover 8, and connecting an air filling pipe 14 on each air bag 9 to a confining pressure controller 13. The position of the cover 8 corresponding to the air adding pipe 14 is provided with a through hole for enabling the air adding pipe 14 to penetrate through the cover 8.

S2, rotating the pressure adjusting knob 18 to enable the pointer on the pressure gauge 17 to reach the target confining pressure required by the corresponding air bag 9, opening the pressurizing knob 16 and the control valve 15 on the air adding pipe 14 to inflate and pressurize the air bag 9, displaying the pressure in the air bag 9 on the electronic counter-pressure gauge 19 in real time until the pressure on the electronic counter-pressure gauge 19 reaches the confining pressure set by the pressure gauge 17, and closing the pressurizing knob 16 and the control valve 15 to enable the confining pressure in the air bag 9 to be maintained at the set confining pressure.

And S3, repeating the step S2 to enable the confining pressure in each air bag 9 to reach the corresponding set confining pressure.

S4, adjusting the position of the cross beam 3 on the stand column 2 so as to adjust the height of the cross beam 3, rotating the pulley 12, winding the steel wire rope, driving the drop hammer 4 to move upwards by the steel wire rope, and lifting the drop hammer 4 to a certain height; the pulley 12 is loosened, the drop hammer 4 falls freely, the drop hammer 4 transmits the impact force to the sample 11 in the air bag 9 through the limiting block 6 and the cover plate 7 on the guide rod 5, different impact loads are applied to the sample 11, and the change of the sample 11 under different impact loads is simulated.

And S5, observing the displacement and the breakage of the sample 11 through the transparent cover 8 and the air bag 9.

Therefore, the impact test device and the impact test method capable of adjusting confining pressure can solve the problem that the conventional impact test device cannot simultaneously research the impact conditions of the railway ballast under different confining pressure conditions.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the invention without departing from the spirit and scope of the invention.

Claims

1. The utility model provides an impact test device of adjustable confined pressure which characterized in that: the device comprises a base, wherein stand columns are arranged on the base, a cross beam is arranged between the stand columns, and a height adjusting structure for adjusting the height of the cross beam is arranged on each stand column; the beam is provided with an impact loading mechanism; be provided with confining pressure control mechanism on the base, confining pressure control mechanism is located the crossbeam under, confining pressure control mechanism is including placing the housing on the base, and the inside of housing is provided with a plurality of gasbag, is provided with the baffle of restriction gasbag axial deformation between the adjacent gasbag, and the inside of gasbag is provided with the sample, the upper and lower surface contact of sample and gasbag, and the gasbag is connected with the confining pressure controller through independent gas filling pipe, is provided with the control valve that the control gas filling pipe opened or closed on the gas filling pipe.

2. The impact test device with adjustable confining pressure according to claim 1, characterized in that: the height adjusting structure comprises adjusting holes, the stand column is provided with a plurality of adjusting holes arranged along the length direction of the stand column, and the bolt penetrates through the adjusting holes to realize the fixed connection of the cross beam and the stand column.

3. The impact test device with adjustable confining pressure as claimed in claim 2, wherein: the housing is a transparent acrylic shell, and the air bag is a transparent air rib type film.

4. The confining pressure adjustable impact test device according to claim 3, characterized in that: and the confining pressure controller is provided with a pressurizing knob for controlling the gas circuit to be switched on or off, a pressure gauge for setting target confining pressure, a pressure adjusting knob for adjusting the pressure of the pressure gauge and an electronic back pressure gauge for displaying the pressure in the gas bag.

5. The impact test device with adjustable confining pressure as recited in claim 4, wherein: the impact loading mechanism comprises a drop hammer and a guide rod, a through hole for the guide rod to pass through is formed in the cross beam, the guide rod is connected with the cross beam in a sliding mode, the drop hammer is sleeved on the guide rod and is connected with the guide rod in a sliding mode, the drop hammer is located right above the center of the air bag, a limiting block for limiting the drop hammer to slip from the guide rod is arranged at the bottom end of the guide rod, a cover plate is arranged right below the guide rod, the bottom end of the guide rod is in contact with the cover plate, and the cover plate covers the air bag and is located in the cover shell; the upright post is provided with a power structure for driving the drop hammer to slide on the guide rod.

6. The impact test device with adjustable confining pressure as recited in claim 5, wherein: the power structure comprises a pulley, the pulley is rotatably arranged on the stand column, and one end of a steel wire rope wound on the pulley is connected with the drop hammer by bypassing a guide wheel arranged on the cross beam.

7. The impact test method of the impact test device with the adjustable confining pressure as claimed in claim 6 is characterized by comprising the following steps:

s4, adjusting the position of the cross beam on the stand column so as to adjust the height of the cross beam, rotating the pulley, winding the steel wire rope, driving the drop hammer to move upwards by the steel wire rope, and lifting the drop hammer to a certain height; the pulley is loosened, the drop hammer falls freely, the drop hammer transmits impact force to a sample in the air bag through a limiting block and a cover plate on the guide rod, and impact load is applied to the sample;