A blasthole stemming material impact resistance testing device and method of use

Abstract

The present application belongs to the technical field of blasting engineering, and particularly relates to a blast hole stemming material impact resistance experimental device and a use method thereof, which comprises: an impact device and an air compression cylinder fixedly arranged in the impact device; the impact device uses a falling hammer to impact a piston rod to compress air in the air cylinder; a lower end of the air cylinder is connected with an upper end of a stemming pipe; the air cylinder and the stemming pipe are internally provided with a bursting disc for converting pressure potential energy of the compressed air in the air cylinder into kinetic energy; the stemming pipe is internally provided with stemming material; a densification observation component is arranged below the stemming material and above the stemming material in the stemming pipe; and a recovery device for recovering the stemming material is arranged below a lower end of the stemming pipe. The densification observation component for arranging the stemming material in the stemming pipe is arranged, and upper and lower vertical rods of the densification observation component extend to outside of the stemming pipe, so that movement and deformation process of the stemming material in the blast hole can be monitored in real time from outside.

Description

Technical Field

[0001] This invention belongs to the field of blasting engineering technology, specifically relating to an experimental device for the impact resistance characteristics of borehole filling materials and its usage method. Background Technology

[0002] In the drill-and-blast rock breaking process, the rock-breaking effect depends not only on the impact force generated by the explosion but also on the duration of the impact of the explosive gases. Proper borehole packing can effectively resist the impact force of the explosion, prolong the duration of the explosive gases' impact, improve the energy utilization rate of the explosive, reduce energy loss, control the distance of flyrock, and improve the blasting effect. Therefore, studying the impact resistance characteristics of borehole packing materials and determining packing materials with excellent impact resistance and their packing parameters is of great significance for improving blasting effectiveness.

[0003] However, under laboratory conditions, it is common practice to simulate blast holes by drilling holes in concrete specimens or using thick-walled steel pipes, and then to simulate the blasting process using appropriate devices in order to observe the dynamic response of the filling material under approximate working conditions.

[0004] However, due to the opacity of concrete and thick-walled steel pipes, it is impossible to effectively observe the shape and velocity of the filling material when it is impacted. At the same time, because the internal space of the simulated blast hole is small, the sensors placed directly inside the simulated blast hole for detection are easily damaged by the impact generated during the simulated blast, thus affecting the detection results.

[0005] In addition, the packing material contains hard materials such as stones and concrete debris, which are prone to scattering under impact, posing a safety hazard to experimental operations. Summary of the Invention

[0006] Based on the above-mentioned technical problems, the purpose of this invention is to provide an experimental device for the impact resistance characteristics of borehole filling materials and its usage method. This experimental device can apply direct gas impact to the borehole filling material indoors, and at the same time, it can monitor the movement state of the filling material from the beginning of the stress to the time it bursts out of the borehole in real time outside the hole.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: An experimental device for testing the impact resistance of borehole filling materials includes: an impact device and an air compression cylinder fixedly installed inside the impact device. The air compression cylinder includes: a cylinder and a piston rod slidably installed at one end inside the cylinder. The impact device uses a falling hammer to impact the piston rod and compress the air inside the cylinder. The lower port of the cylinder is connected to the upper port of a filling tube, and a pressurization hole is opened on the side wall of the lower port of the cylinder. A rupture disc is fixedly installed inside the cylinder at the connection between the cylinder and the filling tube. The rupture disc is used to convert the pressure potential energy of the compressed air inside the cylinder into kinetic energy. Filling material is placed inside the filling tube, and a filling material is inserted into the filling tube below the filling material. A support base is provided, which has ventilation holes, a first mounting hole, and a second mounting hole. A sleeve is fixedly connected in the first mounting hole, and an upper upright is fitted inside the sleeve. The top end of the upper upright passes through the filling material and is fixedly connected to a first gasket, which abuts against the filling material. The bottom end of the upper upright extends to the outside of the lower port of the filling tube. A lower upright is fixedly connected in the second mounting hole, and the top end of the lower upright is inserted into the filling material from the bottom and is fixedly connected to a second gasket. The bottom end of the lower upright extends to the outside of the lower port of the filling tube. A recycling device for recycling the filling material is provided below the lower port of the filling tube. Furthermore, the recycling device includes: a sponge pad, a recycling sleeve, a rubber pad, a laser displacement sensor, and a third bolt; the open end of the recycling sleeve faces the lower port of the packing tube, and the bottom of the recycling sleeve is fixedly connected to the impact device by the third bolt; a partition plate is provided inside the recycling sleeve; above the partition plate, a rubber pad and a sponge pad are stacked sequentially inside the recycling sleeve; below the partition plate, a laser displacement sensor is provided inside the recycling sleeve; a third through hole is provided on the partition plate, the rubber pad, and the sponge pad, and the laser displacement sensor detects the displacement of the packing material through the third through hole; Furthermore, the rupture disc is engraved with a sealing groove and a pre-set groove; Furthermore, the plugging tube consists of a variable diameter section and a plugging section from the upper port to the lower port; Furthermore, a spacer ring is fixedly installed at the top of the cylinder body inside the cylinder. Furthermore, the impact device includes: a vertical frame, a winch fixedly mounted on the top plate of the vertical frame, a steel wire rope wound on the output shaft of the winch passing through the top plate of the vertical frame and fixedly connected to an electromagnetic attractor located between two column feet of the vertical frame, the electromagnetic attractor being fixedly connected to the drop hammer by magnetic force.

[0008] Furthermore, the air compressor cylinder is fixedly mounted within the vertical frame via a fixed bracket, which includes a fixed end and multiple columns. The multiple columns are fixedly connected to the lower end of the fixed end, and the other ends of the multiple columns are fixedly connected to the base plate of the vertical frame. The top of the cylinder is fixedly connected to a cylinder fixed end, and a piston rod guide hole is opened in the middle of the cylinder fixed end. A cylinder port is opened in the middle of the fixed end, and the cylinder body passes through the cylinder port, causing the cylinder fixed end, which is fixedly mounted at the end of the cylinder body, to abut against the fixed end. The cylinder fixed end and the fixed end are fixedly connected by bolts. Furthermore, a guide rail is fixedly installed at the top of the cylinder fixed end, and the part of the piston rod outside the cylinder is installed inside the guide rail. The piston rod collision end is fixedly installed on the piston rod body and is slidably installed on the guide rail. A first through hole is provided at the center of the drop hammer, and the cross-section of the first through hole is smaller than that of the piston rod collision end. The guide rail includes a guide rail fixing plate and four guide slide rods. The size of the guide rail fixing plate is smaller than the first through hole of the drop hammer. The top ends of the four guide slide rods are connected to the guide rail fixing plate by second bolts. The piston rod collision end has four second through holes, and the four guide slide rods pass through the four second through holes and are fixedly connected to the upper surface of the cylinder fixed end. Furthermore, anti-collision posts are installed on the inner sides of the two uprights of the vertical frame. The anti-collision posts include a hydraulic buffer and an anti-collision post base, with the hydraulic buffer fixedly connected to the anti-collision post base.

[0009] In addition, the present invention also provides a method for using the above-mentioned experimental apparatus for testing the impact resistance properties of borehole filling materials, including the following: First, according to the experimental requirements, the corresponding filling tube and filling material are designed and manufactured. Then, the filling tube and filling material are assembled into the experimental device to ensure that the bottom ends of the upper and lower uprights extend to the outside of the lower port of the filling tube. Then, the entire experimental device is adjusted into place according to the lifting height of the falling hammer calculated according to the experimental requirements. After that, the experiment begins. During the experiment, a high-speed camera outside the experimental device is used to obtain the displacement difference of the parts of the upper and lower uprights exposed outside the filling tube, as well as the displacement of the bottom end of the lower upright. The displacement of the packing material is obtained using a laser displacement sensor, and the air pressure inside the cylinder is obtained through a pressure transmitter via a pressure port. The lifting height h of the falling hammer satisfies the following formula: ; In the formula, g is the acceleration due to gravity; v0 is the velocity of the falling hammer when it first contacts the piston rod, and satisfies the following equation: ; In the formula: γ is the maximum downward movement distance of the piston rod driven by the falling hammer; γ is the gas adiabatic index. The weight of the falling hammer; The weight of the piston rod; This refers to the cross-sectional area of ​​the internal space of the cylinder. This is the initial pressure inside the cylinder; Let V be the initial volume of the cylinder, where: ; In the formula: This represents the maximum pressure inside the cylinder, expressed in MPa.

[0010] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention comprises a compaction observation component consisting of upper and lower uprights extending outside the compaction tube, arranged with compaction material inside the filling tube. This allows for real-time monitoring of the movement and deformation of the filling material within the borehole from the outside. Shims are installed at the top of the upper and lower uprights to increase the stress-bearing area and ensure reliable transmission of response signals. Simultaneously, an anti-locking sleeve is installed on the outside of the upper upright to effectively prevent structural locking caused by impact vibration, thereby significantly improving the accuracy and reliability of the monitoring data.

[0011] This invention features a dedicated recovery device located below the outlet of the packing tube. The internal sponge has a constricted structure design, which can effectively capture the material when it is ejected and reduce material damage. The bottom of the device is equipped with a rubber pad, which plays an energy-absorbing and buffering role, preventing the impact force from being transmitted to the laser sensor below, and ensuring the safe operation of key measuring components under high-pressure impact environment.

[0012] This invention uses a falling hammer to push a piston and compress air inside a tube, generating controllable high-pressure gas to simulate an explosive impact load. This structure can effectively control the peak impact pressure, ensuring the realism of the impact process while preventing damage to precision components such as sensors due to overload, thus ensuring that key data can be collected and recorded throughout the entire process. Attached Figure Description

[0013] Figure 1 This is an oblique axonometric view of the experimental apparatus for the impact resistance properties of borehole filling materials according to the present invention; Figure 2 This is an oblique axonometric view of the impact device of the present invention; Figure 3 This is an oblique axonometric drawing of the anti-collision post of the present invention; Figure 4 This is an oblique axonometric view of the air compression cylinder of the present invention; Figure 5 This is an oblique axonometric view of the piston rod of the present invention; Figure 6 This is an isometric view of the cylinder of the present invention; Figure 7This is a cross-sectional view of the cylinder of the present invention; Figure 8 This is an oblique axonometric view of the rupture disc of the present invention; Figure 9 This is an oblique axonometric view of the packing tube of the present invention; Figure 10 This is an oblique axonometric drawing of the fixed bracket of this invention; Figure 11 This is a cross-sectional view of the recycling device of the present invention; Figure 12 This is a schematic diagram showing the installation position of the compaction observation component of the present invention; Figure 13 This is a cross-sectional view of the compaction observation component of the present invention; Figure 14 This is an oblique axonometric view of the support base of the present invention; The components include: 1. Impact device; 11. Winch; 12. Electromagnetic attractor; 13. Drop hammer; 14. Vertical frame; 15. Anti-collision post; 151. Hydraulic buffer; 152. First bolt; 153. Anti-collision post base; 2. Air compressor cylinder; 21. Guide rail; 211. Second bolt; 212. Guide rail fixing plate; 213. Guide slide rod; 22. Piston rod; 221. Second through hole; 222. Piston rod collision end; 223. Rod body; 224. Piston; 23. Cylinder; 231. Threaded hole; 232. Piston rod guide hole; 233. Cylinder fixing end; 234. Cylinder fixing hole; 235. Cylinder body; 236. First flange; 237. Pressurization hole; 238. Intermediate partition. 24. Rupture disc; 241. Sealing groove; 242. Pre-set groove; 25. Stuffing tube; 251. Second flange; 252. Variable diameter section; 253. Stuffing section; 3. Fixed bracket; 31. Cylinder port; 32. Fixed threaded hole; 33. Fixed end; 34. Column; 4. Recovery device; 41. Sponge pad; 42. Recovery sleeve; 43. Rubber pad; 44. Laser displacement sensor; 45. Third bolt; 5. Compaction observation component; 51. Fourth bolt; 52. First gasket; 53. Upper upright; 54. Anti-locking sleeve; 55. Support base; 551. Vent hole; 552. First mounting hole; 553. Second mounting hole; 554. Main body; 56. Lower upright. Detailed Implementation

[0014] The technical solutions adopted in this invention will be further described in detail below with reference to the accompanying drawings and embodiments; First, such as Figure 1 and Figure 11 As shown, this invention provides an experimental device for testing the impact resistance properties of borehole filling materials, comprising: an impact device 1, an air compression cylinder 2, a fixed support 3, a recovery device 4, and a compaction observation component 5, wherein: like Figure 2As shown, the impact device 1 is used to provide impact force to the air compressor cylinder 2. It includes: a vertical frame 14, a winch 11 fixedly mounted on the top plate of the vertical frame 14 by welding, a steel wire rope wound on the output shaft of the winch 11 passing through the top plate of the vertical frame 14 and fixedly connected to an electromagnetic attractor 12 located between two column feet of the vertical frame 14, located below the electromagnetic attractor 12, and tightly connected to the top of the drop hammer 13 by the magnetic force of the electromagnetic attractor 12; specifically, by rotating the winch 11, the electromagnetic attractor 12 is driven to lift the drop hammer 13 to the designed height. The electromagnetic attractor 12 can be remotely controlled. Pressing the control button of the electromagnetic attractor 12 releases the drop hammer 13. The drop hammer 13 acquires initial kinetic energy under its own gravity and moves downward along the column feet of the vertical frame 14 to impact the air compressor cylinder 2. like Figure 4 As shown, the air compression cylinder 2 is fixedly installed in the vertical frame 14 by the cylinder fixing bracket 3, and is installed below the drop hammer 13 in a manner parallel to the column base of the vertical frame 14. It includes: cylinder 23 and piston rod 22 slidably installed in the cylinder 23. Since the piston rod 22 is nested in the cylinder 23, when the piston rod 22 is hit by the drop hammer 13, the piston rod 22 will compress the gas in the cylinder 23. Furthermore, the cylinder body 235 of cylinder 23 has a hollow cylindrical structure, such as... Figure 5 As shown, the rod body 223 of the piston rod 22 is preferably a hollow cylinder to reduce weight and improve the bending resistance of the rod body 223. The end of the rod body 223 located inside the cylinder 23 can be fixedly connected to the piston 224 by means of a threaded connection. The piston 224 slides with the inner wall of the cylinder body 235 of the cylinder 23. The end of the rod body 223 located outside the cylinder 23 faces the drop hammer 13. Its end can be fixedly connected to the piston rod collision end 222 by means of a threaded connection. The shape of the piston rod collision end 222 is preferably a cuboid to increase the force-bearing area. Located at the top of cylinder 23, the cylinder fixed end 233 can be fixedly connected to the cylinder body 235 end of cylinder 23 by welding, such as... Figure 6 and Figure 7 As shown, the cylinder fixed end 233 is a rectangular block with a piston rod guide hole 232 in the middle. The piston rod guide hole 232 allows the piston rod 22 body 223 to pass through freely, so as to guide the piston rod 22 during its movement. Meanwhile, the cylinder fixing end 233 is also used to fix and connect with the cylinder fixing bracket 3. Its shape is set to rectangle, which can increase the contact area between the cylinder body 235 and the cylinder fixing bracket 3, improve the overall strength of the cylinder 23, and prevent the cylinder 23 from tilting during the experiment. like Figure 10As shown, the fixed bracket 3 consists of a fixed end 33 and multiple columns 34. The fixed end 33 is preferably rectangular. The multiple columns 34 are evenly distributed at the lower end of the fixed end 33. One end of the multiple columns 34 can be fixed to the fixed end 33 by welding. The other end of the multiple columns 34 can be fixed to the base plate of the vertical frame 14 in the same way, and the parallelism between the columns 34 and the uprights of the vertical frame 14 is ensured. Furthermore, a cylinder port 31 is provided in the middle of the fixed end 33. The cylinder body 235 of the cylinder 23 can pass through the cylinder port 31, so that the cylinder fixed end 233 fixedly disposed at the end of the cylinder body 235 abuts against the fixed end 33. Four symmetrical fixed threaded holes 32 are provided on the side wall of the fixed end 33. At the same time, cylinder fixing holes 234 matching the positions of the fixed threaded holes 32 are provided at the four corners of the lower part of the cylinder fixing end 233. The fixed threaded holes 32 and the cylinder fixing holes 234 are connected by bolts to fix the cylinder 23 on the cylinder fixing bracket 3, so that the air compressor cylinder 2 is fixedly disposed in the vertical frame 14 through the cylinder fixing bracket 3.

[0015] In addition, as a preferred technical solution, a guide rail 21 can be fixedly installed at the top of the cylinder fixed end 233. The part of the piston rod 22 outside the cylinder 23 is installed inside the guide rail 21. The piston rod collision end 222 is fixedly installed on the top of the piston rod 223. The piston rod collision end 222 is slidably installed on the guide rail 21. At the same time, a first through hole is provided at the center of the drop hammer 13. The first through hole is preferably rectangular and its cross-section is smaller than that of the piston rod collision end 222. In this way, when the drop hammer 13 falls during the experiment, it can pass through the guide rail 21 and hit the piston rod collision end 222, pushing the piston rod 22 to run along the guide rail 21, thereby preventing the piston rod 22 from tilting during the movement. In this embodiment, as Figure 4 As shown, the guide rail 21 includes a guide rail fixing plate 212 and four guide slide rods 213. The size of the guide rail fixing plate 212 is slightly smaller than the first through hole of the drop hammer 13 to ensure that the drop hammer 13 passes smoothly through the guide rail fixing plate 212 and collides with the piston rod 22. The top ends of the four guide slide rods 213 are connected to the guide rail fixing plate 212 by second bolts 211 to fix the relative position of the four guide slide rods 213. The piston rod collision end 222 has four second through holes 221. The four guide slide rods 213 pass through the four second through holes 221 to realize that the guide rail 21 provides guidance for the movement of the piston rod 22. At the same time, mechanical lubricating oil can be applied to the four guide slide rods 213 to reduce mechanical friction loss and ensure smooth operation of the piston rod 22. The bottom ends of the four guide slide rods 213 and the upper surface of the cylinder fixing end 233 have four threaded holes 231 respectively, which are fixed by threaded connection.

[0016] Furthermore, anti-collision posts 15 can be installed on the inner side of the two uprights of the vertical frame 14. The anti-collision posts 15 are used to absorb the excess kinetic energy generated during the fall of the drop hammer 13. Specifically, such as Figure 3 As shown, the anti-collision post 15 includes a hydraulic buffer 151 and an anti-collision post base 153. The anti-collision post base 153 is detachably installed inside the column 34 of the vertical frame 14. The hydraulic buffer 151 adopts an existing structure, which absorbs impact energy through the cooperation of a hydraulic cylinder and a spring. The hydraulic buffer 151 has bolt holes at its four corners. The hydraulic buffer 151 and the anti-collision post base 153 are connected by a first bolt 152. Each anti-collision post base 153 is equipped with two hydraulic buffers 151. The sum of the heights of the hydraulic buffer 151 and the anti-collision post base 153 is the height of the piston rod collision end 222 when it is at the bottom of its stroke, to prevent the falling hammer 13 from causing a secondary collision with the piston rod 22, which would affect the accuracy of the experimental results.

[0017] Located at the bottom of cylinder 23, a pair of pressurizing holes 237 are provided on the side wall of cylinder body 235. One pressurizing hole 237 is used to connect an air compressor to inject air into cylinder 23 to lift piston rod 22. After lifting to the position, the pressurizing hole 237 can be sealed. The other is used to seal and install the first pressure transmitter to monitor the pressure change inside cylinder 23. Preferably, a spacer ring 238 can be fixedly installed at the top of the cylinder body 235 inside the cylinder 23. The spacer ring 238 can ensure that the piston rod 22 has sufficient support length when fully extended to withstand lateral loads. A first flange 236 is fixedly installed on the outer wall of the bottom port of the cylinder 23, and is connected to one end of the packing tube 25 by means of flange connection. At the same time, a rupture disc 24 is also provided at the connection between the cylinder 23 and the packing tube 25. The rupture disc 24 is used for energy storage, that is, to store the high-pressure gas generated inside the cylinder 23 by the piston rod 22. When the gas pressure gradually rises to exceed the design rupture pressure of the rupture disc 24, the rupture disc 24 will be destroyed. At this time, the high-pressure gas will act on the filling material in the filling tube 25 in a manner that simulates the impact airflow generated by an explosion. like Figure 8As shown, the rupture disc 24 is a circular disc that is snapped between the cylinder 23 and the packing tube 25. The rupture disc 24 has a sealing groove 241 and a pre-set groove 242 engraved on it. The sealing groove 241 is used to install a flange gasket to achieve a gas seal. The pre-set groove 242 can change the stress distribution of the rupture disc 24, making it easier to rupture under pressure. The design rupture pressure of the rupture disc 24 can be changed by changing the shape and thickness of the pre-set groove 242. Different design rupture pressures of the rupture disc 24 will generate shock waves with different overpressure peak values. This can be used to systematically analyze and compare the impact effects caused by different charge amounts and types of explosives in the packing material.

[0018] like Figure 9 As shown, the plugging tube 25 includes a variable diameter section 252 and a plugging section 253. The variable diameter section 252 is used to connect with the bottom port of the cylinder 23. A second flange 251 is fixedly provided on the outer wall of the upper port. The second flange 251 is used to connect with the first flange 236 on the outer wall of the lower port of the cylinder 23 to prevent gas from escaping. The variable diameter section 252 adopts a frustum-shaped structure so that the fluid can smoothly transition from one diameter to another. The plugging section 253 is fixedly installed below the variable diameter section 252 by welding. Plugging sections 253 of different diameters can be made to simulate different borehole diameters. The plugging section 253 contains plugging material, and a compaction observation component 5 of the plugging material is also provided on the plugging material. like Figure 12-13 As shown, the compaction observation component 5 includes a fourth bolt 51, a first washer 52, a second washer, an upper upright 53, an anti-locking sleeve 54, a support base 55, and a lower upright 56; The support base 55 is used to seal the packing material disposed inside the packing tube 25 from the bottom. It is inserted into the packing tube 25 from the lower end of the packing tube 25 using an interference fit. Figure 14 As shown, the main body 554 of the support base 55 is in the shape of a frustum, which can improve the frictional resistance between the support base 55 and the filling tube 25. Ventilation holes 551, first mounting holes 552 and second mounting holes 553 are also provided on the main body 554 of the support base 55. Among them: multiple vent holes 551 are provided, and multiple vent holes 551 are evenly distributed on the surface of the main body 554 to ensure the smooth flow of impact airflow. The first mounting hole 552 is located on the edge of the main body 554, and the first mounting hole 552 is used to fix the anti-locking sleeve 54. The second mounting hole 553 is located at the center of the main body 554 and is used to fix the lower upright 56. Furthermore, the upper upright 53 is installed through the filling material, and its upper end is fixedly connected to the first washer 52 by the fourth bolt 51, so that the first washer 52 abuts against the filling material. The other end of the upper upright 53 is installed through the anti-locking sleeve 54 installed in the filling material and fixed in the first mounting hole 552, and extends from the first mounting hole 552 to the outside of the filling tube 25. The anti-locking sleeve 54 is used to ensure that the upper upright 53 runs smoothly and is not jammed by rock debris in the filling material. The top end of the lower support rod 56 is inserted into the filling material from below, and its end is also fixedly connected to the second washer by the connecting fourth bolt 51. The bottom end of the lower support rod 56 is fixed in the second mounting hole 553 and extends to the outside of the filling tube 25.

[0019] Specifically, when the pressure inside the cylinder 23 reaches the designed rupture pressure of the rupture disc 24, the rupture disc 24 ruptures to form an impact airflow that impacts the packing material inside the packing tube 25, thereby achieving the purpose of testing the impact resistance characteristics of the packing material. The impact airflow generated by the rupture of the rupture disc 24 first acts on the upper surface of the packing material and the first gasket 52, causing displacement of the first gasket 52 and the upper surface of the packing material, and simultaneously driving the upper upright 53 to move, while the lower upright 56 ​​does not move. By recording the displacement difference between the lower ends of the upper upright 53 and the lower upright 56 ​​exposed outside the packing tube 25 by a high-speed camera set outside the experimental device, the deformation magnitude of the packing material is determined. As the impact airflow continues to act on the packing material for a longer period of time, the upper upright 53 and the lower upright 56 ​​begin to move synchronously with the packing material. At this time, by recording the displacement of the lower end of the upright 56, the change in the velocity of the packing material inside the packing tube 25 can be calculated.

[0020] like Figure 11 As shown, the packing material recycling device 4 is fixedly installed on the bottom plate of the vertical frame 14 and faces the lower port of the packing tube 25. It includes a sponge pad 41, a recycling sleeve 42, a rubber pad 43, a laser displacement sensor 44, and a third bolt 45. The recycling sleeve 42 is a cylindrical structure with one end open, and its open end is set directly opposite the lower port of the plugging tube 25. The bottom of the recycling sleeve 42 has two symmetrical circular holes for fixing the recycling sleeve 42 to the bottom plate of the vertical frame 14 by the third bolt 45. The recycling sleeve 42 is provided with a partition plate inside, which divides the internal space of the recycling sleeve 42 into upper and lower parts. The upper half of the recovery sleeve 42 is used to place the sponge pad 41 and the rubber pad 43. The sponge pad 41 and the rubber pad 43 are stacked inside the recovery sleeve 42, with the sponge pad 41 placed on top of the rubber pad 43. The sponge pad 41 is designed as a hollow can-shaped structure with the upper opening cross-sectional area slightly smaller than the internal space cross-sectional area, which can effectively prevent the filling material from rebounding out after entering. The sponge pad 41 and the rubber pad 43 can absorb the excess kinetic energy of the filling material through deformation, preventing the filling material from being damaged secondary.

[0021] The lower half of the recovery sleeve 42 is used to place the laser displacement sensor 44. Correspondingly, a third through hole is opened in the partition plate, the sponge pad 41 and the rubber pad 43 for the laser of the laser displacement sensor 44 to be emitted and pointed to the filling material in the filling tube 25. The laser displacement sensor 44 is used to obtain the displacement-time curve of the filling material. The velocity and acceleration-time curve of the filling material are obtained by differentiating the displacement-time curve.

[0022] Secondly, the method of using the experimental device for testing the impact resistance properties of borehole filling materials according to the present invention includes the following steps: Step 1: Select packing tube 25; Based on the experimental requirements, such as the application scenario of the borehole filling material being tested, select a filling tube 25 that corresponds to the actual size of the engineering borehole diameter.

[0023] Step 2: Preparation and installation of packing material; First, design and manufacture the corresponding packing materials according to the experimental requirements, such as yellow mud, rock powder, coarse aggregate, phosphogypsum and other blasting packing materials. Secondly, the installation position of the compaction observation component 5 is determined by the experimental design: the upper end face of its support base 55 needs to contact the lower end of the filling material, while the first pad 52 at the top of the upper pole 53 contacts the upper end face of the filling material. Based on this, the lengths of the upper pole 53 and the lower pole 56 are determined to ensure that after the components are in place, the lower ends of both can protrude about 5 cm beyond the filling tube 25; Then, the support base 55 of the compaction observation component 5 is inserted into the filling tube 25 from the lower port of the filling tube 25 until the upper end face of the support base 55 reaches the preset installation lower edge of the filling material in the borehole. Then, through the upper port of the filling tube 25, the filling material is slowly filled into the filling tube 25. For loose materials such as rock powder and coarse aggregate, they can be poured in directly. For plastic solid materials such as gun mud and phosphogypsum, they need to be laid and compacted layer by layer until the preset filling length is reached. Finally, check whether the lower ends of the upper upright 53 and the lower upright 56 ​​are protruding outside the pipe as required.

[0024] Step 3: Allocate impact energy; According to the experimental requirements, a rupture disc 24 with a corresponding design rupture pressure is selected. Then, the lifting height of the drop hammer 13 is determined based on the design rupture pressure of the rupture disc 24, ensuring that the falling height of the drop hammer 13 is such that the air pressure inside the cylinder 23 just reaches the design rupture pressure of the rupture disc 24. The lifting height h of the drop hammer 13 can be calculated using the following formula: (1); In formula (1): This represents the maximum pressure inside cylinder 23, in MPa. The initial pressure inside cylinder 23, in MPa; The initial volume of the space inside cylinder 23 is measured in meters (m). 3 In this embodiment, the value is 0.01217 m. 3 ; The cross-sectional area of ​​the internal space of cylinder 23, in meters. 2 In this embodiment, it is 0.00785m. 2 ; γ is the maximum downward distance of the piston rod 22 pushed by the drop hammer 13, in meters; γ is the gas adiabatic index, taken as 1.41.

[0025] The design rupture pressure of the rupture disc 24, i.e., the maximum pressure inside the cylinder 23. Substituting into formula (1), the maximum downward movement distance of piston rod 22 is calculated. Then, according to the law of conservation of energy: (2); In formula (2): v0 is the velocity of the drop hammer 13 when it first contacts the piston rod 22, in m / s; g is the acceleration due to gravity, which is generally taken as 9.8 m / s². 2 ; The weight of the drop hammer 13 is in kg. The weight of piston rod 22 is in grams.

[0026] The calculated maximum downward movement distance of piston rod 22 Substituting into formula (2), we obtain the velocity v0 when the drop hammer 13 first contacts the piston rod 22. Then, substituting v0 into the following formula, we obtain the lifting height h of the drop hammer 13:

[0027] In this embodiment, the weight of the drop hammer 13 is set to 1000kg, the initial pressure inside the cylinder 23 is 0.6MPa, and the design rupture pressure of the rupture disc 24 is 5MPa. It is calculated that the maximum downward distance of the piston rod 22 is 1.2m, the initial velocity of the first collision between the drop hammer 13 and the piston rod 22 is 2m / s, and the drop height of the drop hammer should be 0.2m at this time.

[0028] Step 4: Assemble the experimental setup; First, clean the flange and flange gasket to ensure they are free of dirt and rust. Then, align the first flange 236 at the lower end of the cylinder 23 with the second flange 251 at the upper end of the packing tube 25. Place the rupture disc 24 between the cylinder 23 and the packing tube 25. Add a flange gasket between the rupture disc 24 and the second flange 251 and the first flange 236. Tighten the flange bolts clockwise and diagonally, using six tightening wheels. Start by tightening the bolts with a smaller torque and gradually increase to the target tightening torque.

[0029] Step 5: Monitor sensor placement; The laser displacement sensor 44 is placed in the lower layer of the recovery sleeve 42, and the laser is directed at the packing material installed in the packing tube 25. The first pressure transmitter is installed in the pressure port 237 of the cylinder 23 to monitor the magnitude of the impact force of the impinging airflow on the packing material. The second pressure transmitter is installed in an observation hole on the side wall of the packing tube 25 above the packing material to monitor the air pressure inside the packing tube 25. A high-speed camera was placed 5m directly in front of the experimental setup to record the shape and velocity changes of the packing material when it was impacted.

[0030] Step 6: Begin the experiment; After completing the above steps, use an air pump to pressurize the cylinder 23 through the pressurization port 237, pushing the piston rod 22 upward to the top. Then, the winch 11 lifts the drop hammer 13, which is attached to the electromagnetic attractor 12, to a specified height. The electromagnetic attractor 12 is then controlled to release the drop hammer 13, which falls vertically along the vertical frame 14. After the drop hammer 13 contacts the piston rod collision end 222, it pushes the piston rod 22 downward and compresses the air in the cylinder 23. When the pressure in the cylinder 23 reaches the design rupture pressure of the rupture disc 24, the rupture disc 24 ruptures to form an impact airflow that impacts the packing material.

[0031] Step 7: Obtain experimental data: High-speed photography is used to obtain the displacement difference of the lower ends of the upper pole 53 and the lower pole 56 exposed outside the packing tube 25, and at the same time, the displacement of the lower end of the lower pole 56 is obtained. The displacement of the filling material is obtained using a laser displacement sensor 44; The time history curve of the internal air pressure of the plug tube 25 is obtained using the second pressure transmitter.

[0032] After the impact test, save the experimental data, take pictures to record the size and damage morphology of the packing material after the test, fix the drop hammer 13, disconnect the flange connecting the cylinder 23 and the packing tube 25, take out the damaged rupture disc 24, and put all the components back in their original positions so that the test can be carried out again.

Claims

1. An experimental apparatus for testing the impact resistance properties of borehole filling materials, comprising: Impact device (1) and air compression cylinder (2) fixedly installed in impact device (1). The air compression cylinder (2) includes: cylinder (23) and piston rod (22) slidably installed in cylinder (23). The impact device (1) uses a falling hammer (13) to impact piston rod (22) to compress air inside cylinder (23). The lower port of cylinder (23) is connected to the upper port of plugging tube (25). A pressurization hole (237) is opened on the side wall of the lower port of cylinder (23). The feature is that a rupture disc (24) is fixedly installed inside the cylinder (23) at the connection between the cylinder (23) and the plugging tube (25), and the rupture disc (24) is used to convert the pressure potential energy of the compressed air in the cylinder (23) into kinetic energy; The filling tube (25) is filled with filling material, and a support base (55) is inserted into the filling tube (25). The support base (55) has a vent hole (551), a first mounting hole (552) and a second mounting hole (553). The compaction observation component (5) includes: a fourth bolt (51), a first washer (52), a second washer, an upper upright (53), an anti-locking sleeve (54), a support base (55), and a lower upright (56); An anti-locking sleeve (54) is fixedly connected inside the first mounting hole (552). An upper upright (53) is sleeved inside the anti-locking sleeve (54). The top end of the upper upright (53) passes through the filling material and is fixedly connected to the first gasket (52) by the fourth bolt (51). The first gasket (52) abuts against the filling material. The bottom end of the upper upright (53) extends to the outside of the lower port of the filling tube (25). The lower support rod (56) is fixedly connected in the second mounting hole (553). The top end of the lower support rod (56) is inserted into the filling material from the bottom of the filling material and fixedly connected to the second gasket. The bottom end of the lower support rod (56) extends to the outside of the lower port of the filling tube (25). A recycling device (4) for recycling the packing material is provided below the lower port of the packing tube (25). The recycling device (4) includes: a sponge pad (41), a recycling sleeve (42), a rubber pad (43), a laser displacement sensor (44), and a third bolt (45). The experimental setup is equipped with a high-speed camera to obtain the displacement difference between the bottom ends of the upper pole (53) and the lower pole (56) exposed outside the packing tube (25), as well as the displacement of the bottom end of the lower pole (56).

2. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 1, characterized in that, The open end of the recovery sleeve (42) is directly opposite the lower port of the plugging tube (25). The bottom of the recovery sleeve (42) is fixedly connected to the impact device (1) by a third bolt (45). The recovery sleeve (42) is provided with a partition plate inside. Located above the partition plate, rubber pads (43) and sponge pads (41) are stacked in sequence inside the recycling sleeve (42). Located below the partition plate, a laser displacement sensor (44) is installed inside the recycling sleeve (42). A third through hole is opened on the partition plate, the rubber pad (43) and the sponge pad (41). The laser displacement sensor (44) detects the displacement of the filling material through the third through hole.

3. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 1, characterized in that, The rupture disc (24) is engraved with a sealing groove (241) and a pre-set groove (242).

4. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 1, characterized in that, The plugging tube (25) consists of a variable diameter section (252) and a plugging section (253) from the upper port to the lower port.

5. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 1, characterized in that, A spacer ring (238) is fixedly installed at the top of the cylinder body (235) inside the cylinder (23).

6. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 1, characterized in that, The impact device (1) includes: a vertical frame (14), a winch (11) fixedly installed on the top plate of the vertical frame (14), a wire rope wound on the output shaft of the winch (11) passing through the top plate of the vertical frame (14) and fixedly connected to an electromagnetic attractor (12) between two column feet of the vertical frame (14), and the electromagnetic attractor (12) is fixedly connected to the drop hammer (13) by magnetic force.

7. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 6, characterized in that, The air compressor cylinder (2) is fixedly installed in the vertical frame (14) by a fixed bracket (3). The fixed bracket (3) includes a fixed end (33) and multiple columns (34). The multiple columns (34) are fixedly connected to the lower end of the fixed end (33), and the other end of the multiple columns (34) is fixedly connected to the bottom plate of the vertical frame (14). The top of the cylinder (23) is fixedly connected to the cylinder fixed end (233), and the cylinder fixed end (233) has a piston rod guide hole (232) in the middle. The fixed end (33) has a cylinder port (31) in the middle. The cylinder body (235) of the cylinder (23) passes through the cylinder port (31) and the cylinder fixed end (233) fixedly set at the end of the cylinder body (235) abuts against the fixed end (33). The cylinder fixed end (233) and the fixed end (33) are fixedly connected by bolts.

8. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 7, characterized in that, The top end of the cylinder fixed end (233) is fixedly provided with a guide rail (21), the part of the piston rod (22) outside the cylinder (23) is provided inside the guide rail (21), the top end of the piston rod (22) is located, and the piston rod collision end (222) is fixedly provided on the rod body (223) of the piston rod (22), and the piston rod collision end (222) is slidably provided on the guide rail (21); A first through hole is provided at the center of the drop hammer (13), and the cross-section of the first through hole is smaller than that of the piston rod collision end (222). The guide rail (21) includes a guide rail fixing plate (212) and four guide slide rods (213). The size of the guide rail fixing plate (212) is smaller than the first through hole of the drop hammer (13). The top ends of the four guide slide rods (213) are connected to the guide rail fixing plate (212) by a second bolt (211). The piston rod collision end (222) has four through holes (221). The four guide slide rods (213) pass through the four through holes (221) and are fixedly connected to the upper surface of the cylinder fixing end (233).

9. The experimental apparatus for testing the impact resistance properties of borehole filling materials according to claim 8, characterized in that, Anti-collision posts (15) are provided on the inner side of the two uprights of the vertical frame (14). The anti-collision posts (15) include: hydraulic buffers (151) and anti-collision post bases (153). The hydraulic buffers (151) are fixedly connected to the anti-collision post bases (153).

10. A method of using the experimental apparatus for testing the impact resistance properties of borehole filling material according to claim 1, characterized in that, Includes the following: First, according to the experimental requirements, design and manufacture the corresponding filling tube and filling material. Then, assemble the filling tube (25) and filling material into the experimental device to ensure that the bottom ends of the upper pole (53) and the lower pole (56) extend to the outside of the lower port of the filling tube (25). Then, adjust the entire experimental device to the position according to the lifting height of the drop hammer (13) calculated according to the experimental requirements. Then, start the experiment. During the experiment, use a high-speed camera outside the experimental device to obtain the displacement difference of the bottom ends of the upper pole (53) and the lower pole (56) exposed outside the filling tube (25), as well as the displacement of the bottom end of the lower pole (56). The displacement of the filling material is obtained by using a laser displacement sensor (44), the air pressure inside the cylinder (23) is obtained by using a first pressure transmitter through a pressure port (237), and the air pressure inside the filling tube (25) is obtained by using a second pressure transmitter. The lifting height h of the drop hammer (13) satisfies the following formula: （1）； In formula (1), g is the acceleration due to gravity; v0 is the velocity of the drop hammer (13) when it first contacts the piston rod (22), and satisfies the following equation: （2）； In formula (2): γ is the maximum downward movement distance of the piston rod (22) pushed by the drop hammer (13); γ is the gas adiabatic index; The weight of the falling hammer (13); The weight of the piston rod (22); The cross-sectional area of ​​the internal space of the cylinder (23); The initial pressure inside the cylinder (23); Let V be the initial volume of the space inside cylinder (23), where: （3）； In formula (3): The maximum pressure inside cylinder (23) is expressed in MPa.

Images