A simulation device and method for bi-directional impact load test under gradient confining pressure

Abstract

The application discloses a simulation device and method for bidirectional impact load test under gradient confining pressure, which comprises a track, a sample and an impact object. The track comprises a horizontal section, and slope sections are connected to both ends of the horizontal section. The sample is located on the horizontal section, and a gradient confining pressure device is arranged outside the sample to pressurize the sample. The impact object is released from the slope sections as a power input source and moves along the track to collide with the sample to apply impact load to the sample. Impact objects are released on both slope sections to apply bidirectional impact load to the sample. The application can realize that the sample is under gradient confining pressure and can apply impact load to both ends of the sample for multiple times, so as to simulate the blasting damage effect problem of surrounding rock with changing stress state under multiple blasting loads in underground engineering.

Description

Technical Field

[0001] This application relates to the field of blast load impact testing technology, and in particular to a simulation device and method for bidirectional impact load testing under gradient confining pressure. Background Technology

[0002] During the blasting construction of underground caverns, millisecond delay segmented blasting technology is usually adopted. The resulting blasting load will cause multiple impacts on the surrounding rock in a short period of time. At the same time, due to the redistribution of the original stress caused by excavation, an uneven gradient stress state is often formed in the shallow part of the surrounding rock on the cavern outline. Under this on-site construction background, as the blasting excavation progresses, the stress state of the surrounding rock of the underground cavern changes continuously, and the degree of damage to the surrounding rock by blasting increases continuously, which may lead to the destruction and instability of the surrounding rock, thereby affecting the safe construction of the underground cavern. Therefore, in order to ensure the stability of the surrounding rock of the underground cavern during the construction period, it is necessary to study the damage effect of multiple continuous blasting loads on the surrounding rock with constantly adjusted stress state, so as to adjust the blasting parameters or support measures on site in a targeted manner. However, such experimental research involves two key issues: (1) how to achieve the sample being in a gradient confining pressure state; (2) how to control the pulse size and time interval of multiple impact loads. Existing experimental devices are difficult to meet the above requirements at the same time. Summary of the Invention

[0003] This application provides a device and method for simulating bidirectional impact load tests under gradient confining pressure. It enables the application of impact loads to both ends of the specimen multiple times under gradient confining pressure to simulate the blasting damage effect of multiple blasting loads on surrounding rock with continuously changing stress states in underground engineering. The technical solution is as follows:

[0004] The first aspect of this application provides a simulation device for a bidirectional impact load test under gradient confining pressure, comprising a track, a specimen, and an impactor. The track includes a horizontal section, with ramp sections connected to both ends of the horizontal section. The specimen is located on the horizontal section, and a gradient confining pressure device is provided outside the specimen to pressurize it. The impactor, as a power input source, is released from the ramp section and moves along the track to impact the specimen, thereby applying an impact load to the specimen. The impactor is released on both ramp sections to apply a bidirectional impact load to the specimen.

[0005] For example, in a gradient confining pressure bidirectional impact load test simulation device provided in one embodiment, the gradient confining pressure device includes an array of confining pressure sleeves and a confining pressure adjustment device. The specimen is located inside the confining pressure sleeves, and a connecting wing plate is provided on the confining pressure sleeves. The confining pressure adjustment device is provided on the connecting wing plate of each array of confining pressure sleeves to adjust the confining pressure of the confining pressure sleeves and make the confining pressure of the array of confining pressure sleeves gradient distributed. The confining pressure adjustment device includes an adjusting bolt and a nut, and the confining pressure of the confining pressure sleeves is adjusted by adjusting the tightness of the nut.

[0006] For example, in a gradient confining pressure bidirectional impact load test simulation device provided in one embodiment, the confining pressure sleeve is a split structure, including two symmetrically arranged arc-shaped confining pressure plates. The connecting wing plates are provided on both sides of the arc-shaped confining pressure plates. After the two arc-shaped confining pressure plates are joined together, there is a deformation space between the connecting wing plates on both sides of the two arc-shaped confining pressure plates. The connecting wing plates on both sides of the two arc-shaped confining pressure plates are pressurized and fixed by the confining pressure adjustment device.

[0007] For example, in a gradient confining pressure bidirectional impact load test simulation device provided in one embodiment, the gradient confining pressure device further includes a pressure sensor, which is provided between the connecting wing plates on both sides of the two arc-shaped confining pressure plates of each group of confining pressure sleeves to monitor the confining pressure of each group of confining pressure sleeves.

[0008] For example, in a gradient confining pressure bidirectional impact load test simulation device provided in one embodiment, the specimen is a cylindrical rock sample device and is clamped inside the confining pressure sleeve.

[0009] For example, in a gradient confining pressure bidirectional impact load test simulation device provided in one embodiment, the impactor includes a cylindrical body with an impact portion at one end of the body, the impact portion being a necked cylinder. 。

[0010] For example, in a gradient confining pressure bidirectional impact load test simulation device provided in one embodiment, an arc-shaped groove is provided on the track, and the specimen with the gradient confining pressure device is located in the arc-shaped groove and moves along the arc-shaped groove.

[0011] A second aspect of this application provides a method for simulating a bidirectional impact load test under gradient confining pressure, comprising the following steps: S1, placing the specimen equipped with the gradient confining pressure device on the horizontal section of the track; S2, placing impactors at the same or different heights from the ground on the two inclined sections of the track, with the impact portion of the impactors facing the specimen; S3, simultaneously releasing the two impactors and impacting the specimen respectively to apply a bidirectional impact load to the specimen.

[0012] For example, in a method for simulating bidirectional impact load tests under gradient confining pressure provided in one embodiment, in step S1, the length of the horizontal segment is L, the length of the specimen is d, and the distance xL between the specimen and one end of the horizontal segment satisfies the following relationship:

[0013] xL+d≤0.5L.

[0014] For example, in a method for simulating bidirectional impact load tests under gradient confining pressure provided in one embodiment, the mass of the specimen and the impactor is adjusted according to the required impact load pulse size and time interval.

[0015] The beneficial effects of the bidirectional impact load test simulation device and method under gradient confining pressure provided in some embodiments of this application are as follows: The bidirectional impact load test simulation device under gradient confining pressure of this application can apply multiple impact loads to both ends of the specimen in a short period of time to obtain adjustable impact pulses, and can apply adjustable gradient confining pressure to the specimen, realizing that the specimen is under gradient confining pressure and multiple impact loads are applied to both ends of the specimen. The test simulation device of this application is easy to operate, has high test flexibility, and can more realistically simulate the underground cavern of engineering blasting test. It can be used to test and simulate the blasting damage effect of multiple blasting loads on the surrounding rock with constantly changing stress state in underground engineering. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a diagram showing the initial position of the bidirectional impact load test under gradient confining pressure as described in this application;

[0018] Figure 2 This is the bidirectional impact load test state under gradient confining pressure as described in this application. Figure 2 ;

[0019] Figure 3 This is the bidirectional impact load test state under gradient confining pressure as described in this application. Figure 3 ;

[0020] Figure 4 This is the bidirectional impact load test state under gradient confining pressure as described in this application. Figure 4 ;

[0021] Figure 5 This is a schematic diagram of the sample velocity time history curve;

[0022] Figure 6 This is a schematic diagram of the time history curve of the sample under load;

[0023] Figure 7 This is a schematic diagram of the overall structure of the gradient confining pressure device of this application;

[0024] Figure 8 This is a schematic cross-sectional view of the gradient confining pressure device of this application;

[0025] Figure 9 This is a schematic diagram of the impactor structure;

[0026] Figure 10 This is a schematic diagram of the confining pressure gradient curve of the sample in this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0029] The first aspect of this application provides a simulation device for bidirectional impact load tests under gradient confining pressure, such as... Figure 1-4 , Figure 7-9As shown, the system includes a track 1, a specimen 2, and an impactor 3. The track 1 includes a horizontal section 11, with ramp sections 12 connected to both ends of the horizontal section 11. The specimen 2 is located on the horizontal section 11, and a gradient confining pressure device 4 is provided outside the specimen 2 to pressurize the specimen 2. The impactor 3, as a power input source, is released from the ramp section 12 and moves along the track 1 to impact the specimen 2, thereby applying an impact load to the specimen 2. The impactor 3 is released on both ramp sections 12 to apply a bidirectional impact load to the specimen 2.

[0030] According to the above embodiments, the gradient confining pressure bidirectional impact load test simulation device of this application can apply multiple impact loads to both ends of the specimen in a short time to obtain adjustable impact pulses, and can apply adjustable gradient confining pressure to the specimen, realizing that the specimen is under gradient confining pressure and multiple impact loads are applied to both ends of the specimen. The test simulation device of this application is easy to operate, has high test flexibility, and can more realistically simulate the underground cavern of engineering blasting tests. It can be used to test and simulate the blasting damage effect of multiple blasting loads on the surrounding rock with constantly changing stress state in underground engineering.

[0031] For example, in a gradient confining pressure bidirectional impact load test simulation apparatus provided in one embodiment, such as Figure 7-8 As shown, the gradient confining pressure device 4 includes an array of confining pressure sleeves 41 and a confining pressure adjusting device 42. The sample 2 is located inside the confining pressure sleeves 41, and a connecting wing plate 411 is provided on the confining pressure sleeves 41. The confining pressure adjusting device 42 is provided on the connecting wing plate 411 of each array of confining pressure sleeves 41 to adjust the confining pressure of the confining pressure sleeves 41 and make the confining pressure of the array of confining pressure sleeves 41 gradient distributed. The confining pressure adjusting device 42 includes an adjusting bolt 421 and a nut 422. The confining pressure of the confining pressure sleeves 41 is adjusted by adjusting the tightness of the nut 422.

[0032] The number of sets of confining sleeves 41 is determined according to the length of sample 2, for example, Figure 7 An embodiment with four sets of confining sleeves 41 is given, but this application does not limit the number of sets of confining sleeves 41.

[0033] Specifically, such as Figure 7-8 As shown, the confining sleeve 41 has a split structure, including two symmetrically arranged arc-shaped confining plates 412. Connecting wing plates 411 are provided on both sides of the arc-shaped confining plates 412. After the two arc-shaped confining plates 412 are joined together, there is a deformation space between the connecting wing plates 411 on both sides of the two arc-shaped confining plates 412. The connecting wing plates 411 on both sides of the two arc-shaped confining plates 412 are pressurized and fixed by the confining pressure adjusting device 42.

[0034] Specifically, the upper and lower arc-shaped confining plates 412 are joined together to form a set of confining sleeves 41. Multiple sets of confining sleeves 41 compress the sample 2 to generate confining pressure. The adjusting bolts 421 pass through the connecting wing plates 411 on both sides of the two arc-shaped confining plates 412 and are tightened and fixed by nuts 422. When pressurizing, pressure can be applied by turning the nuts 422. Different confining pressure states can be achieved by tightening the nuts 422 to different degrees on each set of confining sleeves 41.

[0035] For example, in a gradient confining pressure bidirectional impact load test simulation apparatus provided in one embodiment, such as Figure 8 As shown, the gradient confining pressure device 4 also includes a pressure sensor 43, which is provided between the connecting wing plates 411 on both sides of the two arc-shaped confining pressure plates 412 of each group of confining pressure sleeves 41 to monitor the confining pressure of each group of confining pressure sleeves 41.

[0036] According to the above embodiment, a pressure sensor 43 is placed between the two connecting flanges 411 of each set of cylindrical confining sleeves 41. The pressure sensor 43 is connected to a computer to monitor the confining pressure. After the sample 2 is combined with the confining sleeve 41, the two connecting flanges 411 of the confining sleeve 41 are aligned on the same horizontal line to facilitate balanced movement. After this, the pressure nut 422 is tightened to fix the pressure device. Then, the sample 2 with the gradient confining device is placed on the horizontal section 11 of the track 1.

[0037] Figure 10 The gradient confining pressure curve applied to sample 2.

[0038] For example, in a gradient confining pressure bidirectional impact load test simulation apparatus provided in one embodiment, such as Figure 8 As shown, the sample is a cylindrical rock sample device, which is clamped inside the confining sleeve.

[0039] For example, in a gradient confining pressure bidirectional impact load test simulation apparatus provided in one embodiment, such as Figure 9 As shown, the impactor 3 includes a cylindrical body 33, and an impact portion 34 is provided at one end of the body 33. The impact portion 34 is a necked cylinder. 。

[0040] For example, in a gradient confining pressure bidirectional impact load test simulation apparatus provided in one embodiment, such as Figure 8 As shown, an arc-shaped groove 13 is provided on the track 1, and the sample 2 with the gradient confining device 4 is located in the arc-shaped groove 13 and moves along the arc-shaped groove 13.

[0041] The arc-shaped groove 13 is in contact with the bottom of the sample 2 with the gradient confining device 4. The purpose of setting the arc-shaped groove 13 is to limit the movement trajectory and reduce friction.

[0042] The second aspect of this application provides a method for simulating a bidirectional impact load test under gradient confining pressure, comprising the following steps: S1, placing the specimen 2 equipped with the gradient confining pressure device 4 on the horizontal section 11 of the track 1; S2, placing impactors 3 at the same or different heights above the ground on the two inclined sections 12 of the track 1, with the impact portion 34 of the impactors 3 facing the specimen 2; S3, simultaneously releasing the two impactors 3, which then impact the specimen 2 respectively, to apply a bidirectional impact load to the specimen 2.

[0043] For example, in a method for simulating bidirectional impact load tests under gradient confining pressure provided in one embodiment, in step S1, the length of the horizontal segment 11 is L, the length of the specimen 2 is d, and the distance xL between the specimen 2 and one end of the horizontal segment 11 satisfies the following relationship:

[0044] xL+d≤0.5L.

[0045] For example, in a method for simulating bidirectional impact load tests under gradient confining pressure provided in one embodiment, the mass of the specimen 2 and the impactor 3 is adjusted according to the required impact load pulse size and time interval.

[0046] Based on the principles of momentum conservation and impulse theorem, this application can realize the pulse pattern of multiple impacts under gradient confining pressure.

[0047] Specifically, Figure 1 This is a diagram showing the starting position of the bidirectional impact load test simulation method under gradient confining pressure proposed in this application. Figure 1 The first impactor 31, the second impactor 32, and the sample 2 are all located on the same track 1, and can move freely on the track 1. Their masses can be adjusted according to the required impact load pulse size and time interval. The first impactor 31 and the second impactor 32 are located at the same height H above the ground on the slope section 12, both serving as power input sources. The first impactor 31 and the second impactor 32 are smooth cylinders; the sample 2 is a cylindrical rock sample device with an attached gradient confining pressure device 4 of length d, initially positioned at a distance xL from the end of the horizontal section 11 of the track 1, where xL + d ≤ 0.5L. At a certain moment, the first impactor 31 and the second impactor 32 are released simultaneously, and they move downwards along the track 1.

[0048] Depend on Figure 2As shown, if track 1 is made sufficiently smooth to negligible frictional resistance, when the first impactor 31 moves to the horizontal section of track 1, the first impactor 31 moves to the right. When the first impactor 31 collides with the sample 2, according to the law of conservation of momentum, the velocity and direction of motion of the two objects change after the collision (the direction after the collision can be the same or opposite, depending on the required impact load pulse size and time interval). That is, after the collision, the first impactor 31 and the sample 2 move at different velocities.

[0049] Depend on Figure 3 As shown, after the first impact, time t1 elapses, and sample 2 collides with the second impactor 32. The magnitude and direction of velocity change after the impact (similarly, the direction after the impact can be in the same or opposite direction, depending on the required impact load pulse size and time interval); after the second impact, time t2 elapses, and the velocity changes... Figure 4 As shown, sample 2 collides with the first impactor 31, changing its velocity or direction again. This completes one impact cycle, and subsequent impacts are similar to the previous one.

[0050] In the above process, the different velocities and impact time intervals of the first impactor 31, the second impactor 32, and the sample 2 can be calculated based on the conservation of momentum and the impulse theorem. By controlling the mass ratio of the first impactor 31, the second impactor 32, and the sample 2, different impact load pulse sizes can be achieved; by controlling the time interval, millisecond-level micro-delay bursting time intervals can be achieved.

[0051] Figure 5 for Figures 1-4 The diagram shows the velocity-time history curve of the sample 2 during an impact cycle. The rightward motion is taken as the positive direction. The oa segment is the time period from the start of the descent of the first impactor 31 to the first collision with the sample 2. The ab segment is the time period at the moment of impact between the first impactor 31 and the sample 2 (very short, negligible compared to the bc and de segments). The bc segment is the motion process of the sample 2 before colliding with the second impactor 32. The cd segment is the collision process between the sample 2 and the second impactor 32. The de segment is the motion process of the sample 2 before rebounding and colliding with the sample 1. The ef segment is the collision process between the sample 2 and the first impactor 31.

[0052] Figure 6 for Figure 5 The corresponding impact load and time history curves are as follows: segment ab represents the process of the first impact of specimen 2 with the first impactor 31, with a peak load of F1; segment cd represents the process of the first impact of specimen 2 with the second impactor 32, with a peak load of -F2; and segment ef represents the process of the second impact of specimen 2 with the second impactor 32, with a peak load of F3.

[0053] Although the embodiments of this application have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this application. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this application is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A simulation device for bidirectional impact load tests under gradient confining pressure, characterized in that, include: The track includes a horizontal section, at both ends of which are connected to ramp sections; The specimen is located in the horizontal section, and a gradient confining pressure device is provided outside the specimen to pressurize the specimen; An impactor, as a power input source, is released from the ramp section and moves along the track to collide with the specimen, thereby applying an impact load to the specimen. In this process, impactors are released on both of the aforementioned slope sections to apply a bidirectional impact load to the specimen. The gradient confining pressure device includes: an array of confining pressure sleeves, with the sample located inside the confining pressure sleeves, and connecting wing plates provided on the confining pressure sleeves; a confining pressure adjusting device, wherein the confining pressure adjusting device is provided on the connecting wing plates of each array of confining pressure sleeves to adjust the confining pressure of the confining pressure sleeves and to make the confining pressure of the array of confining pressure sleeves gradient distributed, the confining pressure adjusting device including adjusting bolts and nuts, and adjusting the tightness of the nuts to adjust the confining pressure of the confining pressure sleeves.

2. The bidirectional impact load test simulation device under gradient confining pressure according to claim 1, characterized in that, The confining sleeve has a split structure, including two symmetrically arranged arc-shaped confining plates. Connecting wing plates are provided on both sides of the arc-shaped confining plates. After the two arc-shaped confining plates are joined together, there is a deformation space between the connecting wing plates on both sides of the two arc-shaped confining plates. The connecting wing plates on both sides of the two arc-shaped confining plates are pressurized and fixed by the confining pressure adjustment device.

3. The bidirectional impact load test simulation device under gradient confining pressure according to claim 2, characterized in that, The gradient confining pressure device also includes a pressure sensor, which is provided between the connecting wing plates on both sides of the two arc-shaped confining pressure plates of each group of confining pressure sleeves to monitor the confining pressure of each group of confining pressure sleeves.

4. The bidirectional impact load test simulation device under gradient confining pressure according to claim 1, characterized in that, The sample is a cylindrical rock sample device, which is clamped inside the confining sleeve.

5. The bidirectional impact load test simulation device under gradient confining pressure according to claim 1, characterized in that, The impactor includes a cylindrical body with an impact portion at one end, the impact portion being a necked cylinder.

6. The bidirectional impact load test simulation device under gradient confining pressure according to claim 1, characterized in that, An arc-shaped groove is provided on the horizontal section of the track, and the sample with the gradient confining device is located in the arc-shaped groove and moves along the arc-shaped groove.

7. The method for simulating a bidirectional impact load test using a gradient confining pressure device according to any one of claims 1-6, characterized in that, Includes the following steps: S1 Place the specimen with the gradient confining pressure device on the horizontal section of the track; S2 Place an impactor at the same or different heights from the ground on the two inclined sections of the track, with the impact portion of the impactor facing the specimen; S3 simultaneously releases the two impactors, which then collide with the specimen to apply a bidirectional impact load to the specimen.

8. The method of the bidirectional impact load test simulation device under gradient confining pressure according to claim 7, characterized in that, In S1, the length of the horizontal segment is L, the length of the sample is d, and the distance xL between the sample and one end of the horizontal segment satisfies the following relationship: xL+d≤0.5L.

9. The method according to claim 7, characterized in that, The mass of the specimen and the impactor is adjusted according to the required impact load pulse size and time interval.

Images