CN116929911A

CN116929911A - Deep high-ground-stress rock burst funnel test experiment device and method

Info

Publication number: CN116929911A
Application number: CN202310907083.1A
Authority: CN
Inventors: 丁晨曦; 郭旭; 杨仁树; 杨立云; 郭啸
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2023-07-21
Filing date: 2023-07-21
Publication date: 2023-10-24

Abstract

The embodiment of the invention discloses a deep high-ground-stress rock burst funnel test experiment device and a test method thereof, and relates to the technical field of burst. Comprising the following steps: a reaction frame; a clamping assembly comprising: the first, second torus pressure transfer pieces, the third and fourth torus pressure transfer pieces; a loading assembly, comprising: the first loading jack is used for applying an acting force to the first torus pressure transmitting piece and simulating deep high ground stress in the second direction; the test piece is clamped under the action of loading force, the test piece is a cylindrical structure test piece made of rock mass, a blast hole with a preset depth is formed in the middle of the cylindrical structure test piece, and a transparent layer with a surface with a viscous surface is coated on the outer circumferential side surface of the cylindrical structure test piece. And the method is convenient for effectively carrying out a deep high-ground-stress rock burst funnel test experiment.

Description

Deep high-ground-stress rock burst funnel test experiment device and method

Technical Field

The invention belongs to the technical field of blasting, and particularly relates to an experimental device and an experimental method for carrying out a deep high-ground-stress rock mass blasting funnel test.

Background

With the acceleration of social development and industrialization progress, space and resource requirements for deep underground are already great trends and necessary choices. The vertical shaft is a throat which enters the deep underground space, and the roadway is an artery of the underground space. At present, the construction of vertical shafts, roadways and the like cannot be broken. In addition, for metal mining, whether it is a sill pillar-less caving method mining, a VCR mining method (Vertical Crater Retreat mining method, vertical deep hole ball cartridge back-off mining method) mining, or a filling mining method currently being carried out by the country, it is necessary to perform efficient mining by instantaneously releasing caving ore body by using explosive energy without explosion. Thus, blasting plays an important and difficult-to-replace role in both deep underground space construction and deep mine mining.

However, as the depth of underground space construction and mine mining increases, the ground stress gradually increases, and the ground stress has a remarkable influence effect on the blasting rupture process and blasting effect. This results in that the blasting basis theory and blasting technique of shallow rock mass (which does not take ground stress into account) will not be applicable to deep rock mass. Therefore, there is a need to perfect the blasting basic theory of deep high ground stress rock mass and upgrade the blasting application technology of deep rock mass. The explosion funnel basic theory is an important component of the rock explosion basic theory, and the deep high-ground stress rock mass explosion funnel test plays a very important role in determining important physical quantities such as specific explosive consumption and the like under the deep high-ground stress condition.

Therefore, there is an urgent need to study the theory of blastfunnels of deep high earth stressed rock mass in order to facilitate blastfunneling experimental tests and evaluation analysis. However, at present, an experimental device and an evaluation analysis method which are specially used for the deep high-ground stress rock burst funnel test are not available, so that the deep high-ground stress rock burst funnel test experiment is difficult to develop.

Disclosure of Invention

In view of the above, the embodiment of the invention aims to provide a deep high-ground-stress rock burst funnel test experiment device and an experiment method thereof, which are convenient for effectively carrying out deep high-ground-stress rock burst funnel test experiments.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

a deep high ground stress rock burst funnel test experiment device, comprising: the reaction frame is formed into a rigid frame structure, and the center of the rigid frame structure is provided with an accommodating space;

the centre gripping subassembly is located in the accommodation space includes: a plurality of torus pressure transfer members, the plurality of torus pressure transfer members comprising: the first annular body pressure transmitting piece, the second annular body pressure transmitting piece, the third annular body pressure transmitting piece and the fourth annular body pressure transmitting piece;

a loading assembly, comprising: one end of the first loading jack is supported on the inner wall of the counterforce frame, the other end of the first loading jack is connected to the outer side wall of the first torus pressure transmission piece, and the first loading jack is used for applying acting force to the first torus pressure transmission piece and simulating deep high ground stress in a first direction;

The second loading jack is circumferentially staggered with the first loading jack, one end of the second loading jack is supported on the inner wall of the counter-force frame, the other end of the second loading jack is connected to the outer side wall of the second torus pressure transmission piece, and the second loading jack is used for applying acting force to the second torus pressure transmission piece and simulating deep high ground stress in a second direction;

under the action of loading force, the first annular body pressure transmitting piece, the second annular body pressure transmitting piece, the third annular body pressure transmitting piece and the fourth annular body pressure transmitting piece are sequentially adjacent and encircled to form a cylindrical structure for clamping a test piece, the first annular body pressure transmitting piece and the fourth annular body pressure transmitting piece are oppositely arranged, and the second annular body pressure transmitting piece and the third annular body pressure transmitting piece are oppositely arranged;

the test piece is a cylindrical structure test piece made of rock mass, a blast hole with a preset depth is formed in the middle of the cylindrical structure test piece, a transparent layer is coated on the outer circumferential side face of the cylindrical structure test piece, and the surface, in contact with the outer circumferential side face, of the transparent layer is a sticky surface.

Optionally, a cushion rubber pad layer is adhered to the inner wall of the clamping assembly.

Optionally, the inner diameter of the cylindrical structure formed by surrounding the clamping assembly is d+2 (D-delta), wherein D is the lower bottom diameter of the test piece, D is the thickness of the cushion rubber cushion layer, and delta is the compression amount of the rubber cushion layer when being loaded with pressure.

Optionally, the first loading jack and the second loading jack are respectively connected with the same oil source system, and the oil source system is used for controlling the two jacks to synchronously load and apply pressure so as to simulate the uniformly distributed ground stress around the blast hole in the deep rock mass;

at least one explosive device is arranged in the blast hole and used for blasting a test piece;

the first dynamic piezoelectric sensor is arranged on a node between the first loading jack and the counter-force frame, the second dynamic piezoelectric sensor is arranged on a node between the second loading jack and the counter-force frame, and the first dynamic piezoelectric sensor and the second dynamic piezoelectric sensor are used for monitoring pressure applied to the test piece in the blasting process.

Optionally, the opening of the cylindrical structure formed by surrounding is provided with a metal cover for collecting the thrown broken stone, a foam lining is arranged in the metal cover, and the metal cover is fixedly connected to the end face of the opening.

Optionally, the first torus conveying piece, the second torus conveying piece, the third torus conveying piece and the fourth torus conveying piece respectively include a plurality of torus conveying pieces of different arc length sizes, the nested stromatolite setting of torus conveying pieces of a plurality of different arc length sizes, and the arc length size of from outside to interior torus conveying piece is by diminishing, be equipped with the hoop spout on the inner wall of the first torus conveying piece in two adjacent stromatolite settings each other, be equipped with on the outer wall of the second torus conveying piece with hoop spout complex slider, the slider is inlayed and is located in the spout, and be equipped with on the first torus conveying piece prevent the slider is followed in the spout is broken away from locking piece.

Optionally, the explosive device comprises: the spherical thin shell structure consists of two hemispherical 3D printing shells, explosive is filled in the spherical thin shell structure, a pinhole is arranged on the spherical thin shell structure, an initiating probe is arranged in the pinhole, one end of the initiating probe penetrates through the pinhole and is placed into the explosive, and the other end of the initiating probe is connected with an external high-voltage pulse initiator.

Optionally, the thickness of the foam lining of the metal cover is not less than 5mm; the plug of the blast hole is a mixture of fine sand and strong glue 502, the grain diameter of the fine sand is 0.4 mm-0.7 mm, and the mass ratio of the fine sand to the strong glue 502 is 2.3.

In a second aspect, the present invention further provides a deep high stress rock burst funnel test experiment method, the method including the steps of:

s10, sampling rock from a blasting site to manufacture a cylindrical structure test piece, and coating a transparent layer on the outer circumferential side surface of the cylindrical structure test piece; wherein the surface of the transparent layer in contact with the outer circumferential side is an adhesive surface;

s20, determining and assembling a clamping assembly of a cylindrical structure with a corresponding size according to the diameter of a test piece of the cylindrical structure coated with the transparent layer, placing the test piece in the center of the clamping assembly, and adjusting the position;

S30, calculating the pressure applied by the first loading jack and the second loading jack according to the deep ground stress value of the rock mass simulated by the test piece, and loading the rock mass to simulate the deep ground stress environment of the real rock mass;

s40, loading the test piece in the center in the clamping assembly step by utilizing the first loading jack and the second loading jack in a staged manner so as to apply pressure to the test piece clamped in the center in a staged manner, and monitoring whether the pressure readings of the first loading jack and the second loading jack are stable or not;

s50, when the pressure indication of the first loading jack and the second loading jack is in a stable state, filling the spherical thin shell structure with explosive, and placing an initiating probe into the explosive through a pinhole;

s60, detonating the explosive through the detonating probe, continuously monitoring whether the pressure indication numbers of the first loading jack and the second loading jack are in a stable state or not in the detonating process, and adhering broken rock in situ by utilizing the viscosity of the transparent layer so as to keep the morphological integrity of the broken test piece.

Optionally, in step S10, the method further includes: cutting a cushion rubber cushion layer with a size matched with the circumference of the outer circumferential side surface of the cylindrical structure test piece, and wrapping the cushion rubber cushion layer on the transparent layer;

In step S20, the method further includes: determining and assembling a clamping assembly of a cylindrical structure with a corresponding size according to the diameter of a cylindrical structure test piece wrapped with the cushion rubber layer and the transparent layer;

in step S60, continuously monitoring whether the pressure readings of the first loading jack and the second loading jack are in a stable state by using the first dynamic piezoelectric sensor and the second piezoelectric sensor;

step S60 further includes: in the detonation process, the buffer cushion layer is utilized to absorb part of explosion stress wave so as to reduce the influence of the explosion stress wave on the pressure indication stability of the monitoring display of the first dynamic piezoelectric sensor and the second dynamic piezoelectric sensor and the influence on the loading and pressing stability of the first loading jack and the second loading jack;

monitoring whether the pressure indication fluctuation range exceeds a preset pressure threshold value;

if so, increasing the thickness of the cushion rubber layer according to a preset thickness increasing ratio, restarting the experiment, and absorbing the explosion stress wave by utilizing the thickened cushion rubber layer until the pressure indication fluctuation range monitored by the first dynamic piezoelectric sensor and the second piezoelectric sensor is within a preset pressure threshold.

Optionally, in step S40, the step of loading the stage by stage on the clamping assembly by using the first loading jack and the second loading jack to apply pressure to the stage of the test piece clamped in the center includes:

the clamping assembly is loaded step by utilizing a first loading jack and a second loading jack in three stages; wherein, in the first stage, the pressure is applied to 0.5F from 0, and the loading time of the stage is 10-20 s; a second stage of applying a pressure from 0.5F to 0.9F, the loading time of the stage being 40-60 s; a third stage of applying a pressure from 0.9F to F for a loading time of not less than 150s, and standing for a predetermined period of time after the pressure is applied to F for the first time to see whether the pressure readings of the first and second loading jacks are stable;

if the pressure is unstable, repeating the loading step of the third stage until the pressure indication of the jack is stable at the pressure F. .

According to the experimental device and the experimental method for testing the deep high-ground-stress rock burst funnel, provided by the embodiment of the invention, the deep high-ground-stress simulation of the predetermined burst rock can be realized by mutually and cooperatively matching the counterforce frame, the clamping assembly, the loading assembly and the cylindrical structural test piece, and the acting force of the annular body pressure transmitting piece on the test piece can be changed by adjusting the pressure of the loading jack, so that different ground stress conditions can be simulated. Moreover, the clamping assembly is loaded and pressed through the loading assembly, so that the tight contact between the test piece and the pressure transmission piece is ensured, and the stable boundary constraint and reaction force are provided through the reaction frame, so that the problems of punching and funnel deformation can be prevented, and the accuracy and reliability of the test are improved. Further, through cladding transparent layer on the outer circumference side of cylinder structure test piece, a surface of this transparent layer has the viscosity, is convenient for keep the integrality of the broken back form of test piece like this, is convenient for follow-up convenient observation after the blasting damage situation of test piece to can see crack distribution and the funnel form of test piece after the blasting directly perceivedly, thereby conveniently evaluate blasting funnel test experimental effect. Therefore, the test experiment of the deep high-ground-stress rock burst funnel is conveniently and effectively carried out.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic structural view of an embodiment of the test device for testing a blasting hopper of a deep high-ground stress rock mass.

FIG. 2 is a schematic view of an embodiment of the torus pressure transfer of FIG. 1.

FIG. 3 is a schematic structural view of an embodiment of the cylindrical structural test piece in FIG. 1.

FIG. 4 is a graph showing the variation of a dynamic piezoelectric sensor pressure Q with time T when the dynamic piezoelectric sensor pressure Q does not exceed (1.+ -. 5%) F in an embodiment of the present invention;

FIG. 5 is a graph showing the variation of the dynamic piezoelectric sense pressure Q over time T when it exceeds (1+5%) F in an embodiment of the present invention;

FIG. 6 is a graph showing the variation of the dynamic piezoelectric sense pressure Q (Q less than (1-5%) F) with time T when Q is less than (1-5%) F, according to an embodiment of the present invention;

FIG. 7 is a schematic view of a metal cover according to an embodiment of the invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

It should be understood that the described embodiments are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

FIG. 1 is a schematic structural view of an embodiment of the test device for testing a blasting hopper of a deep high-ground stress rock mass. FIG. 2 is a schematic view of an embodiment of the torus pressure transfer of FIG. 1. FIG. 3 is a schematic view of an embodiment of the cylindrical structural test piece in FIG. 1; referring to fig. 1 to 3, the deep high ground stress rock burst funnel test experiment device provided by the embodiment of the invention includes: the reaction force frame 100 is configured as a rigid frame structure, and the center of the rigid frame structure is provided with an accommodating space; the reaction frame 100 is made of a material with higher rigidity, such as 45 # steel, and the reaction frame 100 of the experimental device is formed by splicing or welding, so that the reaction frame is prevented from being obviously deformed under the action of a higher reaction force, and smooth development of a blasting funnel test experiment is ensured.

The clamping assembly 200, located in the accommodating space, includes: a plurality of torus pressure transfer members, the plurality of torus pressure transfer members comprising: the first torus pressure transfer member 201, the second torus pressure transfer member 202, the third torus pressure transfer member 203 and the fourth torus pressure transfer member 204;

it can be understood that, in order to perform the test experiment and the effect analysis and evaluation of the deep ground stress bursting funnel, one of the key points is to simulate the high ground stress state of the deep rock mass, so in this embodiment, the hydraulic jack uniformly transmits the pressure to the test piece, so that the high ground stress state of the deep rock mass can be simulated, so that the method is suitable for the development of the deep ground stress bursting funnel test.

The loading assembly 300 includes: the first loading jack 301, one end of which is supported on the inner wall of the reaction frame 100, and the other end of which is connected to the outer side wall of the first torus pressure transmitting member 201, the first loading jack 301 is used for applying a force to the first torus pressure transmitting member 201 to simulate the deep high ground stress in the first direction;

the second loading jack 302 is circumferentially staggered with the first loading jack 301, one end of the second loading jack is supported on the inner wall of the reaction frame 100, the other end of the second loading jack is connected to the outer side wall of the second torus pressure transmitting member 202, and the second loading jack 302 is used for applying acting force to the second torus pressure transmitting member 202 to simulate deep high ground stress in a second direction;

In this embodiment, the clamping assembly 200 is wrapped and clamped with four quarter-round steel pressure transmitters, wherein in the position shown in fig. 1, the left and upper round steel pressure transmitters are driven by a hydraulic jack, respectively, to apply pressure to the test piece, and the lower and right round steel pressure transmitters are supported on the reaction frame 100 to provide reaction force.

Under the action of loading force, the first torus pressure transmitting piece 201, the second torus pressure transmitting piece 202, the third torus pressure transmitting piece 203 and the fourth torus pressure transmitting piece 204 are sequentially adjacent and encircled to form a cylindrical structure for clamping the test piece 400, the first torus pressure transmitting piece 201 and the fourth torus pressure transmitting piece 204 are oppositely arranged, and the second torus pressure transmitting piece 202 and the third torus pressure transmitting piece 203 are oppositely arranged;

the test piece 400 is a cylindrical structure test piece made of rock mass, a blast hole with a preset depth is formed in the middle of the cylindrical structure test piece, a transparent layer is coated on the outer circumferential side surface of the cylindrical structure test piece, and the surface, in contact with the outer circumferential side surface, of the transparent layer is a sticky surface.

In the aspect of the test piece 400, in order to facilitate effect evaluation and analysis by combining CT tomography after the blasting experiment, in some embodiments, the test piece 400 is designed as a cylindrical structure test piece, the cross section of the test piece 400 is circular, and an explosive is perforated and placed in the middle of the test piece 400. The configuration of the test piece 400 and the relative positions of the blast holes are shown in fig. 2. The cylindrical rock specimen 400 has a cross-sectional diameter D and a height H. The depth of the central blast hole of the cylindrical rock specimen 400 is h. According to the related requirements of the blasting funnel theory on the blasting resistance line, the relation between the section diameter D of the cylindrical rock specimen 400 and the blast hole depth h is required to be satisfied, and h is smaller than 0.5D. In this way, it is ensured that during blasting, rock is thrown from the upper surface of the test piece 400, thereby forming a blasting funnel.

In addition, in the follow-up blasting experiment, the test piece 400 can take place to be broken under the blasting load effect, and the form is difficult to keep integrality, is inconvenient to blasting effect analysis, consequently, through being located the cladding has the transparent layer on the outer circumference side of cylinder structure test piece, the transparent layer with the surface that the outer circumference side contacted is the sticky surface, like this, during experimental analysis at the back, can utilize the adhesion of sticky surface with broken test piece 400 normal position, can directly carry out CT scanning etc. with the test piece 400 of wrapping up in the transparent layer, can guarantee the integrality of test piece 400 form after the blasting like this, is favorable to improving the reliability of analysis result.

According to the experimental device and the experimental method for testing the deep high-ground-stress rock burst funnel, provided by the embodiment of the invention, the deep high-ground-stress simulation of the predetermined burst rock can be realized by mutually cooperating the counterforce frame 100, the clamping assembly 200, the loading assembly and the cylindrical structural test piece, and the acting force of the annular body pressure transmitting piece on the test piece 400 can be changed by adjusting the pressure of the loading jack, so that different ground stress conditions can be simulated. Moreover, the clamping assembly 200 is loaded and pressed by the loading assembly, so that the tight contact between the test piece 400 and the pressure transmission piece is ensured, and the stable boundary constraint and reaction force are provided by the reaction frame 100, so that the problems of punching and funnel deformation can be prevented, and the accuracy and reliability of the test are improved. Further, through cladding the transparent layer on the outer circumference side of cylinder structure test piece, a surface of this transparent layer has the viscosity, is convenient for keep the integrality of the broken back form of test piece 400 like this, is convenient for follow-up convenient observation after the blasting damage situation of test piece 400 to can see crack distribution and the funnel form of test piece 400 after the blasting directly perceivedly, thereby conveniently evaluate blasting funnel test experimental effect. Therefore, the test experiment of the deep high-ground-stress rock burst funnel is conveniently and effectively carried out.

In addition to the above-mentioned problems and solutions, in order to further enable the loaded pressure to be uniformly transferred to the test piece 400, in some embodiments, a cushion rubber pad layer 401 is attached to the inner wall of the clamping assembly 200. Like this, wrap up test piece 400 with the cushion of certain thickness, then put into the loading again, in the loading process, the rubber cushion can play the transitional effect of even transmission pressure, makes the even transmission of loaded pressure to test piece 400 on to simulate deep even stress loading environment.

In some embodiments, the cushion gum layer 401 is a rubber pad. If the test piece 400 is directly wrapped and clamped by the rubber pad, the test piece 400 is easily attached to the rubber pad under the pressure application effect of each loading jack, and the test piece is difficult to completely take off for analysis after blasting. To avoid this, the transparent layer may be a plastic film, so that the test piece 400 may be separated from the rubber pad, thereby avoiding this problem.

In addition, in order to ensure that the device can be suitable for carrying out burst funnel test experiments on test pieces 400 of different sizes, namely, applying pressure to test pieces 400 of different diameters and carrying out the experiments, in one embodiment, a plurality of dimension specifications are required to be designed for four torus pressure transfer pieces applying pressure and counter force to test pieces 400 so as to be suitable for the conditions of test pieces 400 of different sizes. However, this design is cumbersome.

Thus, to be able to accommodate a variety of different sized test pieces 400 with a single set of devices, in some embodiments, the clamping assembly 200, which provides support and reaction to the test piece 400, may be designed in a nested combination as shown in FIG. 2. Specifically, the first torus pressure transmitting member 201, the second torus pressure transmitting member 202, the third torus pressure transmitting member 203 and the fourth torus pressure transmitting member 204 respectively include a plurality of torus pressure transmitting members with different arc length sizes, the torus pressure transmitting members with different arc length sizes are nested and stacked, the arc length sizes of the two torus pressure transmitting members which are stacked adjacently are changed from large to small, the inner wall of the first torus pressure transmitting member of the two torus pressure transmitting members which are stacked adjacently is provided with a circumferential chute, the outer wall of the second torus pressure transmitting member is provided with a slider matched with the circumferential chute, the slider is embedded in the chute, and the first torus pressure transmitting member is provided with a locking member which prevents the slider from separating from the chute.

Illustratively, the (1) portion of the assembly may be used when the diameter of the cylindrical test piece 400 is relatively large, and the (1) (2) (3) portions of the assembly may be used in combination when the diameter of the cylindrical test piece 400 is relatively small. Of course, according to the actual experimental requirements, the annular joint structures of the various annular body pressure transfer pieces can be customized to adapt to the size of the commonly used experimental test piece 400. For example, to ensure that several combined parts can be tightly combined together in a circumferential direction, and to better transmit stress, in some embodiments, the contact surface of the circumferential combined part of each torus pressure transmitting member is subjected to polishing treatment, and lubricant such as vaseline is smeared on the contact surface of the combined part, so that sufficient transmission of pressure can be ensured.

In another alternative, the first torus pressure transfer 201, the second torus pressure transfer 202, the third torus pressure transfer 203, and the fourth torus pressure transfer 204 each include two torus pressure transfer disposed adjacent to each other in and out of a stack, wherein one inner torus pressure transfer has one torus and one inner wall for forming a gripping surface;

an outer annular body pressure transfer member having a toroidal surface and an inner wall;

the elastic elements can be compression springs and are respectively supported and arranged between the inner annular body pressure transmission piece and the outer annular body pressure transmission piece, so that a spacing space is formed between the inner annular body pressure transmission piece and the outer annular body pressure transmission piece, and the elastic elements can stretch and retract according to the diameter change of the cylindrical structural test piece so as to adapt to the test pieces 400 with different diameter specifications;

in other embodiments, a plurality of adjusting members may be further provided, respectively connected to both ends of the elastic member and penetrating through the sidewall of the outer ring body, for adjusting the telescopic length of the elastic member, thereby controlling the test piece 400 of maximum diameter specification that is allowed to be adapted. Specifically, the adjusting member may be a screw, a threaded rod, or the like capable of changing the length by rotating or sliding. One end of the adjusting part is connected with one end of the elastic element, the other end of the adjusting part penetrates through the inner wall of the outer ring body, and the inner wall of the outer ring body is provided with a fixed ring or a movable ring matched with the adjusting part. By tightening or loosening the adjustment member in a predetermined rotational direction, both ends of the elastic member can be brought close to or away from each other, thereby changing the telescopic length of the elastic member, and controlling the test piece 400 of the maximum diameter specification that is allowed to be accommodated.

Based on the above description, emphasis is placed on the process of placing the test piece 400 into the clamping assembly 200 and applying pressure to the test piece 400. Firstly, wrapping a preservative film on the periphery of a cylindrical structure test piece, and wrapping 2-3 layers. As described above, one of the functions is to separate the test piece 400 from the rubber mat after the blasting. The rubber cushion layer of the matched size is then cut according to the size of the cylindrical test piece 400. As shown in fig. 3, taking the height H and the bottom diameter D of the rock test piece 400 as an example, the length pi D and the width H of the rectangular rubber cushion are cut. Where pi is the circumference ratio, pi=3.14 is generally desirable. The thickness of the preservative film wrapped around the rock specimen 400 is negligible. The thickness of the selected rubber cushion layer is d, and the recommended thickness of the thickness d is 2-5 mm. On the basis, the cut rubber cushion layer is tightly wrapped on the cylindrical rock test piece 400, and the wrapped rubber cushion layer joint is tightly stuck by 502 strong glue, and care needs to be taken to ensure that the stuck part is smooth and even. The diameter of the bottom of the test piece 400 wrapped by the rubber cushion layer is D+2d.

Considering that the rubber cushion layer is compressed and the thickness is reduced when the pressure is applied by each loading jack, the thickness reduction of the rubber cushion layer is denoted as delta. In general, the thickness of the rubber cushion layer is reduced by an amount Δ= (0.3 to 0.5) d under pressure. Then, after the cushion compression thickness becomes small, the bottom diameter of the test piece 400 wrapped with the rubber cushion is finally d+2 (D- Δ).

Thus, in some embodiments, the inner diameter of the cylindrical structure formed around the clamping assembly 200 is d+2 (D- Δ), where D is the bottom diameter of the test piece 400, D is the thickness of the cushion rubber layer 401, and Δ is the amount of compression of the rubber layer when it is pressurized.

In this embodiment, the corresponding torus pressure transfer member is selected and assembled such that the innermost ring diameter of the torus pressure transfer member is d+2 (D- Δ). In order to facilitate the conversion of the pressure applied by the subsequent jack, the relevant dimensions D, H, d and Δ are defined herein as having a length unit of m (meters). In this embodiment, when the torus pressure transmitting member is processed and prefabricated, the size requirement of the commonly used test piece 400 is fully considered, and the inner diameter of the cylindrical structure is calculated according to the above formula, so that the torus pressure transmitting member meeting the experimental development requirement can be combined and matched.

Referring again to fig. 1, the first loading jack 301 and the second loading jack 302 share two jacks, namely the upper jack and the left jack in the orientation of fig. 1. In the process of pressing by using the jacks, the loading of the two jacks must be ensured to be synchronous. If not synchronized, the pressure application may be uneven, failing to simulate the deep ground stress environment more realistically, and even crushing the rock test piece 400 during the pressurization process. Thus, to achieve synchronization of the pressurization of the two jacks, in some embodiments, the first loading jack 301 and the second loading jack 302 are each connected to the same oil source system for controlling the simultaneous loading pressurization of the two jacks to simulate evenly distributed ground stress around the borehole in the deep rock mass.

In this embodiment, the jacks in the two directions are connected externally and share one oil source system, so that the two jacks can realize complete synchronous loading under the condition of sharing the oil source system.

Specifically, at least one explosive device is placed in the blast hole and is used for blasting the test piece 400;

the first dynamic piezoelectric sensor is arranged on a node between the first loading jack 301 and the reaction frame 100, the second dynamic piezoelectric sensor is arranged on a node between the second loading jack 302 and the reaction frame 100, and the first dynamic piezoelectric sensor and the second dynamic piezoelectric sensor are used for monitoring the pressure applied to the test piece 400 in the blasting process.

The blasting funnel experiment requires that the upper end face of the test piece 400 is a free face, namely, the periphery of the test piece 400 is subjected to confining pressure, but the upper end of the test piece 400 is free and unconstrained, so that rock mass at the upper end of the test piece 400 after blasting can be freely thrown and form the blasting funnel after being broken. However, the blasted rock fragments have different shapes and different blocking, which are important data sources for subsequent blast effect evaluation and analysis. These pieces of rock must then be collected. Rock cracking and throwing caused by explosive explosion is a very rapid process, firstly, all the blasted rock fragments are collected, and the fragments are ensured to maintain the original appearance in the collecting process, and secondary crushing is not generated any more. If secondary crushing occurs, which is not caused by blasting, analysis and data processing of fragments based thereon do not meet the accuracy and objectivity of scientific experiments. The data which is processed and collected later is distorted, and the accuracy and reliability of analysis results are not high.

Therefore, referring to fig. 7, in some embodiments, a metal cover 205 for collecting the thrown broken stone is disposed at the opening of the cylindrical structure, a foam liner 206 is disposed inside the metal cover 205, and the metal cover 205 is fixedly connected to an end surface of the opening. In this way, the blasted rock fragments can fly into the cavity of the metal cap 205, facilitating the collection of the rock fragments. In addition, because the foam lining is arranged in the metal cover, the rock fragments collide with the foam lining, and the kinetic energy of the fragments can be absorbed by the foam fragments, so that secondary crushing caused by the collision of the fragments with the inner wall of the metal cover is avoided, and the original form of the blasted fragments can be effectively ensured. After blasting, the metal cover can be unscrewed to collect rock fragments therein, which is beneficial to ensuring the accuracy and reliability of the subsequent analysis results.

Specifically, the thickness 206 of the foam liner of the metal cover 205 is not less than 5mm; a circle of screw threads 207 are arranged at the mouth of the metal cover, and matched screw thread notches are also arranged at the corresponding opening positions of the clamping assembly 200 so as to be mutually matched and fixedly installed, so that the metal cover can be screwed on the clamping assembly 200, and the metal cover is fixed.

In addition to the improvements of the foregoing technical solutions, in this embodiment, a series of improvements are made in the aspects of charging, blocking, explosive loading, and the like, and the details are as follows:

the experimental device provided by the embodiment of the invention aims to perform a blasting funnel test under the condition of deep high ground stress. Depending on the basic requirements of the blasting hopper test, the explosive needs to be a spherical charge, i.e. the shape of the charge needs to be spherical or nearly spherical. The explosive adopted in the model experiment is lead azide or DDNP, and two hemispherical thin-shell structures can be printed by adopting a 3D printing method and can be combined together to form a whole spherical thin-shell structure. The spherical thin shell structure is filled with explosive, so that a spherical explosive package required by a blasting hopper experiment is formed. Thus, in some embodiments, the explosive device comprises: the spherical thin shell structure consists of two hemispherical 3D printing shells, explosive is filled in the spherical thin shell structure, a pinhole is arranged on the spherical thin shell structure, an initiating probe is arranged in the pinhole, one end of the initiating probe penetrates through the pinhole and is placed into the explosive, and the other end of the initiating probe is connected with an external high-voltage pulse initiator. Wherein, the thin shell generally refers to a shell with the thickness not more than 0.3 mm.

Specifically, in order to ensure the experimental effect, the inner diameter phi of the 3D printing shell needs to be calculated according to the explosive loading amount and the explosive density, so that a thin shell structure suitable for experimental requirements is printed. The specific inner diameter phi is calculated as follows. Because of the model experiment, the cylindrical rock test piece 400 is relatively small in size, so the amount of explosive used in the experiment is relatively small. In the experiment, the mass of the explosive is set as M, and the mass M of the explosive is recommended to be not more than 5 g. The density of the explosive is ρ. In order to facilitate the conversion of the inner diameter phi of the subsequent 3D printing shell, the units of related physical quantities are all made of international standard units, the unit of explosive mass M is kg, the unit of explosive density rho is kg/M3, and the unit of the inner diameter phi is M. From this, it can be deduced that the inner diameter phi of the 3D printing shell is

In addition, a particularly small pinhole is pre-cracked on the 3D printed shell, an initiating probe is placed into the explosive through the pinhole, and then an external line of the initiating probe is connected to an external high-voltage pulse initiator through the blast hole. The thus-prepared cartridge (including the probe and the external wire) is placed in the bottom of the blast hole of the test piece 400.

In addition, for the explosion funnel experiment, the blocking quality of the blast hole is also particularly important, if the blocking of the blast hole is not firm and tight enough, then the phenomenon of punching holes easily occurs in the explosion experiment process, so that the explosion funnel is difficult to generate, or the related data of the explosion funnel can be distorted, and the explosion funnel test experiment can not be smoothly implemented. Therefore, the blast hole blocking must be ensured in the experiment The mass of the plug. By way of an attempt to use a variety of plugging media and plugging patterns, in this example, a mixture of fine sand and strong glue 502 was determined to be used as the plug. However, parameters and proportions of fine sand and strong glue 502 are also critical, in the application, in order to ensure the quality of blast hole blockage, the particle size of the fine sand is required, and if the particle size of the fine sand is too large, gaps among sand particles are too large, and the blockage strength is too low. The grain size of the fine sand cannot be too small, and the overall strength of the fine sand after being mixed and solidified with the glue is too low. It is verified by a plurality of experimental tests that the optimal grain size interval of the fine sand is preferably determined to be 0.4 mm-0.7 mm. In addition, the mixture ratio of the fine sand and the strong glue 502 also has specific requirements, the mass of the fine sand is M1, and the mass of the strong glue 502 is M2. Also, according to multiple experimental measurements, the mass ratio of the fine sand to the strong glue 502 is foundWhen the mixture is solidified, the strength is maximized. Therefore, when the mixture of fine sand and strong glue 502 is used as the blast hole blockage in the experiment, the mass ratio of the fine sand to the strong glue 502 is 2.3.

In this embodiment, through adopting explosive device, loading and the blocking process condition of above-mentioned scientific experiment determination, can guarantee the quality that the big gun hole blockked up, satisfy the basic requirement that blasting funnel experiment developed.

Example two

Based on the experimental device provided by the embodiment, the invention also provides a deep high-stress rock burst funnel test experimental method, which comprises the following steps:

s20, determining and assembling a clamping assembly 200 of a cylindrical structure with a corresponding size according to the diameter of a test piece of the cylindrical structure coated with a transparent layer, placing the test piece 400 in the center of the clamping assembly 200, and adjusting the position;

s30, calculating the pressure to be applied by the jack of the first loading jack 301 and the jack of the second loading jack 302 according to the deep ground stress value of the rock mass simulated by the test piece 400, wherein the pressure is used for loading to simulate the deep ground stress environment of the real rock mass;

s40, loading the first loading jack 301 and the second loading jack 302 on the clamping assembly 200 step by using the stages so as to apply pressure to the test piece 400 clamped in the center step by step, and monitoring whether the pressure readings of the first loading jack 301 and the second loading jack 302 are stable;

S50, when the pressure indication of the first loading jack 301 and the second loading jack 302 is in a stable state, filling the spherical thin-shell structure with explosive, and placing an initiating probe into the explosive through a pinhole;

s60, detonating the explosive through the detonating probe, continuously monitoring whether the pressure indication of the first loading jack 301 and the second loading jack 302 is in a stable state or not in the detonating process, and adhering broken rock in situ by utilizing the viscosity of the transparent layer so as to keep the morphological integrity of the broken test piece 400.

Optionally, in step S40, the step of loading the clamping assembly 200 step by using the first loading jack 301 and the second loading jack 302 to apply pressure to the centrally clamped test piece 400 step by step includes:

in this embodiment, the pressure applied by the jack is converted before the jack is used to apply pressure to the test piece 400. In general, the unit of jack indication is generally t (ton), and for our experimental conditions, the jack with the measuring range of 30t can be selected to meet the experimental requirements. According to the requirement of experimental design, the deep ground stress of the simulation test piece 400 is P, and the unit is MPa. From this, the pressure F, in t, applied by each jack to the test piece 400 can be calculated. Can be obtained according to conversion and derivation Wherein g is the gravity acceleration rate,generally take g=9.8 m/s ² . Therefore, under the condition that the relevant parameters of the rock test piece 400 are determined, given the deep ground stress P required by the experiment, the pressure F which each jack should apply to the test piece 400 can be obtained, and thus, the deep ground stress required by the experiment can be ensured through accurate calculation.

The clamping assembly 200 is loaded step by step in three stages by using a first loading jack 301 and a second loading jack 302; wherein, in the first stage, the pressure is applied to 0.5F from 0, and the loading time of the stage is 10-20 s; a second stage of applying a pressure from 0.5F to 0.9F, the loading time of the stage being 40-60 s; a third stage of applying a pressure from 0.9F to F for a loading time of not less than 150s, and standing for a predetermined period of time after the pressure is applied to F for the first time to see whether the pressure readings of the first and second loading jacks 301 and 302 are stable;

if the pressure is unstable, repeating the loading step of the third stage until the pressure indication of the jack is stable at the pressure F.

Illustratively, the application of pressure may be divided into three main stages.

(1) First stage (rapid pressurization stage): this stage is to apply pressure from 0 to 0.5F using a jack. The pressure in the stage is relatively small, the jack can be used for quick pressurization, the common oil source system is started to control the two jacks to synchronously pressurize, and the loading time in the stage can be completed within 10-20 s.

(2) Second stage (medium-speed pressurization stage): this stage is to apply pressure from 0.5F to 0.9F using a jack. The pressure at this stage is relatively high and the loading rate cannot be too high, which if too high may result in uneven stress transfer inside the rock test piece 400. And starting the common oil source system to control the two jacks to synchronously pressurize, wherein the loading time of the stage can be completed within 40-60 s.

(3) Third stage (low-speed pressurization stage): this stage is to apply pressure from 0.9F to F using a jack. The stage where the pressure is the greatest is also the most important stage, and the loading speed must be slow and stable. And starting a common oil source system to control the two jacks to synchronously pressurize, wherein the loading time of the stage is not less than 150s. And it should be noted that after the first application of pressure to F, it was observed whether the indication of the jack was stable after 10 minutes of standing. Because cracks and voids may exist within the rock test piece 400, under the action of the pressure for a longer period of time, the cracks and voids may close, which may result in some compression of the entire volume of the rock test piece 400, which may result in a reduction in the pressure that was originally applied. So after the first application of pressure to F, it was left to stand for 10min to see if the indication of the jack was stable. If the indication is stable, the stress loading is smooth, and the later experimental procedure can be performed. If the indication is unstable, which is generally shown by a decrease in the indication, it is indicated that the cracks and pores in the rock are compressed, and the third stage of loading is repeated, the pressure is applied to F again, and then the jack is kept still for 10 minutes to see whether the indication of the jack is stable or not, and the operation is repeated until the indication of the jack is finally stabilized at the pressure F. The following experimental procedure can then be performed.

In addition, in this embodiment, in order to achieve a predetermined experimental effect, the operations of loading, plugging, and explosion loading are performed after the simulated ground stress loading is completed. I.e. after the pressure F of the test piece 400 in the loading device has stabilized, the subsequent loading, plugging and explosion loading operations can be performed. This order cannot be reversed and is not arbitrarily replaced by a person skilled in the art as required, which the inventors of the present application have made extensive studies in engineering practice. Because if the charging, blocking and then the application of pressure are performed first. If the loading fails during the application of pressure, the explosive and the plugging material must also be cleaned out, which is extremely cumbersome and dangerous and may be explosive. This order must not be reversed nor easily imaginable.

Next, the specific procedure of step S60 will be described in detail: it is important to the experiments of the present application that a stable pressure is applied to the test piece 400, including the loading process in step S40 and the loading process in step S60. In the experiment, the pressure applied to the test piece 400 before the explosive in the test piece 400 exploded simulated the deep high ground stress environment in which the test piece 400 was located. It is important for scientific research whether this pressure can remain stable during the course of the experiment. By performing the loading operation using the aforementioned experimental device, it is possible to ensure that the pressure applied to the test piece 400 before blasting is stable. However, if the test piece 400 is excessively broken during the blasting of the test piece 400, the integrity and the bearing capacity of the test piece 400 are difficult to ensure, and the static pressure applied to the test piece 400 is significantly changed, so that the rigor of the test is difficult to ensure. Therefore, in the foregoing embodiment, two dynamic piezoelectric sensors are disposed at the node between the jack and the inner wall of the reaction frame 100, and the sampling frequency of the sensors is very high, so that the dynamic change process of the pressure applied to the test piece 400 during the blasting process of the test piece 400 can be accurately monitored. Based on the collected pressure change curve during blasting, it can be estimated whether the experiment is stable or not and effective.

As can be seen from the foregoing description of the embodiment, if the test piece 400 is required to be in the ground stress state of P, the pressure applied by each jack is converted to be F. Then, each dynamic piezoelectric sensor has an indication Q, and the indication q=f before blasting. In the blasting process, the dynamic piezoelectric sensor can rapidly collect pressure feedback of the jack in the blasting process, and a relation curve of pressure Q and time T in the blasting process is obtained. As shown in FIG. 4, if the variation range of the pressure Q measured by the dynamic piezoelectric sensor does not exceed + -5% F, the pressure during the blasting of the test piece 400 is considered to be relatively stable, and meets the requirements of the experimental design. As shown in fig. 5 and 6, if the pressure Q measured by the dynamic piezoelectric sensor is changed by more than ±5% F, the pressure during the blasting of the test piece 400 is considered to be unstable and does not meet the requirement of the experimental design, and then some measures are required to re-perform the experiment. Thus, a reference basis is provided for whether the experimental result is reliable.

Specifically, if the pressure Q measured by the dynamic piezoelectric sensor changes more than ±5% F, we should take which measures to restart the experiment. This is also adjusted in two cases, as follows.

Case (1): the pressure Q measured by the dynamic piezoelectric sensor is greater than (1+5%) F, i.e., Q > (1+5%) F, as shown in FIG. 5. This is typically due to the fact that the reaction force of the explosion stress wave to the annular steel assembly shown in fig. 3 is too great, i.e. the transmission of the explosion stress wave has an excessive effect on the loading system such as the jack. In this case, the experiment needs to be carried out again by increasing the thickness of the rubber cushion layer wrapped around the rock test piece 400, and the thickness increase is recommended to be 5% each time until the pressure requirement monitored by the dynamic piezoelectric sensor is met. Of course, a more damped rubber mat layer may be used instead. Both methods can well solve the problem of excessive projection of the explosion stress wave, thereby reducing the influence of the stress wave.

Thus, in some embodiments, in step S10, the method further comprises: cutting a cushion rubber cushion layer 401 with a size matched with the circumference of the outer circumferential side surface of the cylindrical structure test piece, and wrapping the cushion rubber cushion layer on the transparent layer;

in step S20, the method further includes: determining and assembling a clamping assembly 200 of a cylindrical structure with a corresponding size according to the diameter of the cylindrical structure test piece wrapped with the cushion rubber layer 401 and the transparent layer;

In step S60, the first dynamic piezoelectric sensor and the second piezoelectric sensor are used to continuously monitor whether the pressure readings of the first loading jack 301 and the second loading jack 302 are in a stable state;

step S60 further includes: in the detonation process, the buffer cushion layer 401 is utilized to absorb part of the explosion stress wave so as to reduce the influence of the explosion stress wave on the pressure indication stability of the monitoring display of the first dynamic piezoelectric sensor and the second dynamic piezoelectric sensor and the influence on the loading and pressing stability of the first loading jack 301 and the second loading jack 302;

monitoring whether the pressure indication fluctuation range exceeds a preset pressure threshold value; if so, increasing the thickness of the cushion rubber layer 401 according to a preset thickness increasing ratio, restarting the experiment, and absorbing the explosion stress wave by using the thickened cushion rubber layer 401 until the pressure indication fluctuation range monitored by the first dynamic piezoelectric sensor and the second piezoelectric sensor is within a preset pressure threshold. Thus, the fluctuation range of the pressure indication in the blasting process can be ensured to meet the experimental requirement value.

Case (2): the pressure Q measured by the dynamic piezoelectric sensor is less than (1-5%) F, i.e., Q < (1-5%) F, as shown in fig. 6. This is generally due to the fact that the explosive charge is too large, which results in a relatively large number of cracks in the cylindrical rock specimen 400 during blasting, the specimen 400 is very broken, the integrity of the specimen 400 is poor, and the pressure exerted by the jack on the rock specimen 400 is instantaneously relieved much, so that the pressure Q monitored by the dynamic piezoelectric sensor is less than (1-5%) F. In this case, to reduce the explosive amount for re-experiment, the amount of the explosive is reduced by 5% each time, until the pressure requirement monitored by the dynamic piezoelectric sensor is met.

Thus, in another alternative embodiment, step S60 further comprises: in the detonation process, the buffer cushion layer 4 is utilized to absorb part of explosion stress wave so as to reduce the influence of the explosion stress wave on the pressure indication stability of the monitoring display of the first dynamic piezoelectric sensor and the second dynamic piezoelectric sensor and the influence on the loading and pressing stability of the first loading jack 3 and the second loading jack 3;

monitoring whether the pressure indication fluctuation range exceeds a preset pressure threshold value; if yes, reducing the explosive amount according to a preset explosive amount reduction ratio, and restarting the experiment until the pressure indication fluctuation range monitored by the first dynamic piezoelectric sensor and the second piezoelectric sensor is within a preset pressure threshold. In this way, the fluctuation range of the pressure indication in the blasting process can be ensured to meet the experimental requirement value.

Further, in some embodiments, in step S40, further comprising: the pressure applied by the first loading jack 301 and the second loading jack 302 is uniformly transferred onto the test piece 400 through the cushion rubber layer 401 in a transitional manner, so that uniform stress in different deep positions can be simulated, and the test piece 400 can be ensured not to be crushed or deviated in position.

In step S60, the test piece 400 is separated from the cushion rubber layer 401 by the transparent layer during the detonation.

In a first embodiment, a metal cover is provided to facilitate collection of the blasting hopper pieces and to prevent secondary crushing. Correspondingly, in the method of the embodiment, the method further includes:

providing a metal cover, and fixedly mounting the metal cover on the end surface of the opening of the clamping assembly 200, so that the opening of the metal cover is arranged corresponding to the throwing opening of the explosive device; the metal cover is provided with an opening and a collecting cavity;

a foam lining is arranged on the inner wall of the metal cover, so that the foam lining and the inner wall of the metal cover cooperate to form a buffer space;

in step S60, after the explosive device is detonated, rock fragments enter a buffer space and are absorbed by a foam liner to prevent the fragments from being secondarily broken after striking the inner wall of the metal cover;

the metal cover is unscrewed and the rock fragments which remain in the original form are collected.

In the embodiment, as the foam lining is arranged in the metal cover, the rock fragments collide with the foam lining, and the kinetic energy of the fragments can be absorbed by the foam fragments, so that secondary crushing caused by the collision of the fragments to the inner wall of the metal cover is avoided, the original form of the blasted fragments can be effectively ensured, and the fragments are convenient to collect.

After collecting the blast fragments, the method further comprises: performing blasting block size and CT tomographic analysis

Wherein, the analysis of blasting block size mainly comprises: after blasting, performing blasting block size analysis on the rock fragments collected in the metal cover by combining a method of screening and analyzing to obtain distribution characteristics of large blocks with different sizes; and the fractal theory can be further combined to evaluate the blasting effect.

The analysis of CT tomography is mainly as follows: after blasting, the rock test piece 400 is subjected to CT fault scanning, the form, the volume and the like of the blasting chamber are obtained through three-dimensional reconstruction, main geometric parameters of the blasting funnel, such as the radius, the depth and the like of the blasting funnel, are automatically calibrated, and the effect of the blasting funnel is evaluated. In addition, the fracture and damage characteristics of the test piece 400 after the explosion can be analyzed, and the damage distribution characteristics of the rock mass at the bottom of the explosion funnel under different explosion funnel conditions can be obtained by combining the damage theory.

Specifically, the method further comprises the following steps: s70, screening and analyzing the collected rock fragments to obtain the distribution characteristics of the large blocks with different sizes; carrying out fractal dimension calculation on the distribution characteristics of the large blocks with different sizes, and evaluating the blasting effect; CT fault scanning is carried out on the blasted rock test piece 400, and the shape, the volume and the like of the funnel blasting cavity are obtained through three-dimensional reconstruction; then, main geometric parameters of the funnel explosion cavity, such as radius, depth and the like of the explosion cavity, are automatically calibrated, and the explosion cavity effect is evaluated, such as the ratio of the explosion cavity volume to the theoretical volume, the similarity of the explosion cavity shape and the ideal shape and the like are calculated; analyzing the fracture and damage characteristics of the test piece 400 after blasting, such as calculating the area of a damage area, the damage degree and the like; and analyzing the damage distribution characteristics of the rock mass at the bottom of the explosion cavity under different explosion cavity conditions, such as calculating the range, depth, density and the like of the damage area.

The fractal dimension calculation is carried out according to the distribution characteristics of the large blocks with different sizes, and the evaluation of the blasting effect mainly comprises the following steps: s1, classifying and screening the blasted rock fragments according to the size to obtain the number of fragments with different grades. Typically, it will be classified into a number of fragments, such as 10cm, 5cm, 2cm, etc. S2, calculating the proportion of fragments of each level. For example, the number of fragments in the order of 10cm represents a substantial proportion of the total fragments. And S3, drawing a logarithmic graph according to the fragment proportion of each level and the corresponding level size. S4, calculating a fractal dimension by using a fractal dimension formula according to the logarithmic graph. The fractal dimension formula can adopt a Baogelin fractal dimension formula, the fractal dimension is a numerical value for quantitatively describing the complexity degree of the shape of the object, the capability of blasting to break the rock into different sizes can be described, the size of the fractal dimension can reflect the blasting effect, the larger the value is, the larger the blasting breaks the rock into more smaller fragments, and the effect is better. In this embodiment, the fractal dimension reference value under the same blasting condition can be calibrated, and compared with the actual calculated value, the blasting effect can be quantitatively evaluated.

In the embodiment, by using CT tomography and three-dimensional reconstruction, the information such as the form and the volume of the explosion cavity can be intuitively obtained, and the main geometric parameters of the explosion cavity can be automatically calibrated, so that the evaluation efficiency and objectivity of the explosion cavity effect are improved. In addition, by analyzing the fracture and damage characteristics of the post-blasting test piece 400, the damage distribution characteristics of the rock mass at the bottom of the blasting chamber under different blasting chamber conditions can be revealed, so that a basis is provided for optimizing blasting parameters and controlling blasting effects under deep ground stress conditions.

Further, the effect that the rock is broken into different sizes is converted into a number through fractal dimension calculation, and the blasting effect can be quantitatively and intuitively reflected.

As can be seen from the disclosure, the deep high-ground stress rock burst funnel test experimental device and the experimental method thereof provided by the embodiment of the invention respectively provide corresponding invention improvement points in terms of the device structure, the explosive device, the charging blockage and explosion loading, the real-time monitoring and dynamic adjustment of loading pressure in the blasting process, the collection device of burst funnel fragments, measures for preventing secondary breaking and the like, and all the parts cooperate and correspond to each other, so that a series of problems of carrying out deep high-ground stress rock burst funnel test are overcome, and the burst funnel test experimental device and method steps for carrying out deep high-ground stress rock burst are provided, thereby facilitating the effective carrying out of the deep high-ground stress rock burst funnel test experiment, and further carrying out research and analysis on the burst funnel test in deep high-ground stress rock burst.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments.

Those skilled in the art will appreciate that implementing all or part of the above-described methods in accordance with the embodiments may be accomplished by way of a computer program stored on a computer readable storage medium, which when executed may comprise the steps of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), or the like.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims

1. Deep high ground stress rock burst funnel test experimental apparatus, its characterized in that includes: the reaction frame is formed into a rigid frame structure, and the center of the rigid frame structure is provided with an accommodating space;

2. The deep high stress rock burst funnel test device according to claim 1, wherein a cushion rubber layer is attached to the inner wall of the clamping assembly.

3. The deep high stress rock burst funnel test device according to claim 1, wherein the inner diameter of the cylindrical structure formed by surrounding the clamping assembly is d+2 (D-delta), wherein D is the lower bottom diameter of the test piece, D is the thickness of the cushion rubber layer, and delta is the compression amount of the rubber layer when the cushion rubber layer is loaded with pressure.

4. The deep high-stress rock burst funnel test experiment device according to claim 1, wherein the first loading jack and the second loading jack are respectively connected with the same oil source system, and the oil source system is used for controlling the two jacks to synchronously load and apply pressure so as to simulate the uniformly distributed ground stress around the blast hole in the deep rock;

5. The deep high-stress rock mass blasting funnel test experiment device according to claim 1, wherein a metal cover for collecting thrown broken stone is arranged at the opening of the enclosed cylindrical structure, a foam lining is arranged inside the metal cover, and the metal cover is fixedly connected to the end face of the opening.

6. The deep high-stress rock burst funnel test experiment device according to claim 1, wherein the first annular body pressure transmitting part, the second annular body pressure transmitting part, the third annular body pressure transmitting part and the fourth annular body pressure transmitting part respectively comprise annular body pressure transmitting parts with different arc length dimensions, the annular body pressure transmitting parts with different arc length dimensions are nested and stacked, the arc length dimension of the annular body pressure transmitting parts from outside to inside is changed from large to small, an annular chute is arranged on the inner wall of a first annular body pressure transmitting part of two annular body pressure transmitting parts which are adjacently stacked, a sliding block matched with the annular chute is arranged on the outer wall of the second annular body pressure transmitting part, the sliding block is embedded in the chute, and a locking part for preventing the sliding block from being separated from the chute is arranged on the first annular body pressure transmitting part.

7. The deep high stress rock mass blasting funnel test device of claim 1 or 2, wherein the explosive device comprises: the spherical thin shell structure consists of two hemispherical 3D printing shells, explosive is filled in the spherical thin shell structure, a pinhole is arranged on the spherical thin shell structure, an initiating probe is arranged in the pinhole, one end of the initiating probe penetrates through the pinhole and is placed into the explosive, and the other end of the initiating probe is connected with an external high-voltage pulse initiator.

8. The experimental device for testing the explosion funnel of the deep high-stress rock mass, according to claim 5, wherein the thickness of the foam lining of the metal cover is not less than 5mm;

the plug of the blast hole is a mixture of fine sand and strong glue 502, the grain diameter of the fine sand is 0.4 mm-0.7 mm, and the mass ratio of the fine sand to the strong glue 502 is 2.3.

9. The test experiment method for the deep high-stress rock burst funnel is characterized by comprising the following steps of:

10. The method of testing a deep high stress rock burst funnel according to claim 8, wherein in step S10, the method further comprises: cutting a cushion rubber cushion layer with a size matched with the circumference of the outer circumferential side surface of the cylindrical structure test piece, and wrapping the cushion rubber cushion layer on the transparent layer;