Multi-field coupled blasting vibration simulation experimental device and experimental method for sandstone mines

Abstract

The present invention belongs to the field of engineering blasting, and discloses a multi-field coupling sandstone mine blasting vibration simulation experimental device and an experimental method, including: a fluid driving mechanism and a spacing adjustment assembly linked to the fluid driving mechanism; a hose connects a water storage cylinder and a water storage bag, water flow impacts an impeller, the impeller rotates, the rotating shaft of the impeller wraps and connects a rope, the rope pulls a piston to move upward, a negative pressure is formed between the water storage cylinder and the water storage bag, and water in the water storage bag is extracted through the hose, so that the weight of the water in the water storage bag is reduced, such that when an elastic member generates an axial elastic deformation, the thickness of the air spacer layer also changes, and passive adjustment of the air layer spacing is achieved through fluid mechanics characteristics, so that the displacement of the air layer forms a dynamic balance with the water injection volume, and an experimenter can remotely control the size of the water body in a water-containing fractured rock mass, and the position of the air spacer layer in the PVC pipe can be adaptively adjusted according to the size of the water body to reduce potential safety hazards.

Description

Technical Field

[0001] The present invention relates to the field of engineering blasting, and in particular to a multi-field coupled sandstone mine blasting vibration simulation experimental device and an experimental method. Background Art

[0002] With the rapid development of infrastructure construction in my country, the demand for efficient and green mining of quartz sandstone ore, a key raw material for cement production, is becoming increasingly urgent. In open-pit mining, deep-hole bench blasting technology is widely used due to its high efficiency and low cost. However, the well-developed rock mass in the mining area, with its frequent water content, leads to a high rate of large blocks and excessive blasting vibration during the blasting process. This not only affects mining efficiency and increases secondary crushing costs, but also poses a safety hazard to nearby buildings.

[0003] For example, a method, system, equipment, and medium for controlling the size of blocks in mining blasting construction, for example, is disclosed in application number CN119618006A. By establishing a quantitative relationship between the thickness of the air gap and the total length of the charge, the thickness of the air gap is manually adjusted to perform multiple blasts, thereby obtaining different changes in explosive stress caused by different thicknesses of the air gap. Furthermore, by using the same method, the rock mass to be blasted is replaced with a water-bearing rock mass. By observing the distribution of rock blocks after the explosion, the influence of water in the rock mass on the stress propagation characteristics of the rock mass during the explosive explosion can be obtained.

[0004] However, when it is directly applied to water-bearing rock, the volume in the cracks becomes unstable due to the entry of gravel into the cracks during the excavation of the rock, resulting in the water remaining in the cracks being different from the volume of the original experimental water, while the air interval layer between the explosives remains unchanged. If the thickness of the air interval layer is greater than the predetermined thickness of the original experimental water, the blasting vibration will be less intense than expected in the experiment, resulting in incomplete blasting of the rock around the water, especially when the water weakens the stress generated by the blasting. If the thickness of the air interval layer is less than the predetermined thickness of the original experimental water, the explosion stress will be concentrated and damage will be caused to the surrounding rock and buildings, increasing the safety risk. The rock structure is unstable after excavation, and manual adjustment of the air layer interval between the explosives is prone to safety hazards. Summary of the invention

[0005] In response to the shortcomings of the existing technology, the purpose of the present invention is to provide a multi-field coupled sandstone mine blasting vibration simulation experimental device and experimental method, which solves the problem in the existing technology that due to the entry of gravel into the cracks during the rock excavation process, the water volume remaining in the cracks is different from the original water volume, and manual adjustment of the air layer spacing between explosives is prone to safety hazards.

[0006] The purpose of this disclosure can be achieved through the following technical solutions:

[0007] Multi-field coupling sandstone mine blasting vibration simulation experimental device, comprising: a fluid driving mechanism and a spacing adjusting assembly linked to the fluid driving mechanism;

[0008] The fluid driving mechanism includes a flow channel communicating with a water tank and an impeller disposed in a water filling tank. The water in the water tank moves through the water filling tank into a groove body opened in a rock mass to simulate the water body in a water-containing fractured rock mass under natural conditions;

[0009] The spacing adjusting assembly includes a vertical water storage cylinder. A piston in sealed sliding fit is provided in the inner cavity of the water storage cylinder. The rotating shaft supporting the rotation of the impeller is connected to the top of the piston by a connecting rope;

[0010] A hose connects the water storage cylinder and a water storage bag, and the bottom of the water storage bag supports one end of a vertically placed PVC straight pipe filled with explosives. The water storage bag forms a vertically downward pressure load on the PVC straight pipe through its own weight;

[0011] Elastic members are arranged between adjacent explosives in the PVC straight pipe, and the elastic members keep an air interval layer formed between adjacent explosives;

[0012] The water flow impacts the impeller, and the impeller rotates. The rotating shaft of the impeller winds the connecting rope, and the connecting rope pulls the piston to move upward, creating a negative pressure between the water storage cylinder and the water storage bag, and extracting the water in the water storage bag through the hose, reducing the weight of the water in the water storage bag. The pressure change of the water storage bag on the PVC straight pipe causes the elastic members in the PVC straight pipe to produce axial elastic deformation, so that when the elastic members produce axial elastic deformation, the thickness of the air interval layer also changes, thereby adjusting the thickness of the air interval layer between adjacent explosives in real time, making the blasting vibration generated by the two explosives within a preset range.

[0013] In some disclosures, the impeller is fixed inside the water filling tank through an impeller frame. The rotating shaft of the impeller is perpendicular to the water flow direction. The water flow flowing out of the flow channel contacts the blades at the bottom of the impeller and drives the impeller to rotate counterclockwise.

[0014] In some disclosures, a positioning hole penetrating a support platform is opened between the water tank and the water filling tank, and a cylinder is disposed through the inner side of the positioning hole. A slotting assembly is provided at the lower end of the cylinder.

[0015] In some disclosures, a water guide plate is fixed at the lower end of the water filling tank, and a spring rope is fixed between the slotting assembly and the water guide plate.

[0016] In some disclosures, the slotting assembly includes a motor, a milling cutter disc and a dust shield. The motor is fixed at the lower end of the cylinder, and a milling cutter disc is fixed at the output end of the motor. A dust shield is coaxially fixed outside the milling cutter disc, and the spring rope is fixed to the dust shield on the side away from the water guide plate.

[0017] In some disclosures, an electric telescopic rod is fixed to one end of the motor away from the milling cutter head. A slider is fixed to the upper end surface of the motor, and the upper end of the slider is fixedly connected to the lower end of the cylinder. The moving path of the slider is parallel to the moving path of the electric telescopic rod.

[0018] In some disclosures, the PVC straight pipe includes a fixing cylinder, a limiting plate, a return spring, and a support plate. The lower end of the water storage cylinder is clamped with the fixing cylinder. A limiting plate is slidably arranged inside the fixing cylinder. A return spring is fixed to the lower end surface of the limiting plate, and a support plate is fixed to the bottom of the return spring. The space supported by the return spring between the limiting plate and the support plate is an air spacer layer. A plurality of explosives are placed inside the fixing cylinder, and the explosives are respectively placed on both sides of the air spacer layer. The material of the return spring is natural rubber, and the thickness is 1 - 2 cm.

[0019] In some disclosures, a positioning groove is opened at the upper end of the fixing cylinder, and a clamping rod adapted to the positioning groove is fixed to the bottom of the fixing cylinder.

[0020] In some disclosures, a clamping ring is fixed to the bottom of the water storage cylinder, and a limiting protrusion adapted to the clamping ring is fixed to the outer wall of the uppermost fixing cylinder.

[0021] A multi-field coupling sandstone mine blasting vibration simulation experiment method includes the following steps:

[0022] S1. Prepare standard rock samples. First, make a plurality of complete rock mass samples according to the sandstone hardness, and then make cylindrical rock specimens with the same hardness as the sandstone. Measure the load when the rock is damaged by a compressor, and calculate the point load intensity.

[0023] S2. Vertically place the explosive in a roll shape into the fixing cylinder. The upper and lower ends of the explosive are respectively in contact with the support plate and the limiting plate. The interval between the support plate and the limiting plate between adjacent two explosives is the air spacer layer.

[0024] S3. Place a suitable rock mass inside the support frame, and place the predetermined crack position corresponding to the upper and lower milling cutter heads. Start the motor to drive the milling cutter head to rotate at a high speed, and then start the cylinder. The cylinder drives the milling cutter head to move vertically downward until the milling cutter head contacts the rock mass and cuts the inside of the rock mass to form a groove on the rock mass surface to simulate the crack of the water-containing cracked rock mass in the natural state. And drill blast holes around the crack through a drilling machine. Fix the probe connected to the blasting vibration instrument on the ground near the rock. Start the instrument before blasting.

[0025] S4. At this time, place the PVC straight pipe with explosives inside the blast hole, and the upper end of the PVC straight pipe is directly below the water storage cylinder. The water storage bag applies a downward pressure on the explosives and the return spring, so that the return spring is in a compressed state at this time, and the air spacer layer between adjacent explosives is the smallest.

[0026] S5. At this time, start the water pump outside the water tank, so that the water in the water tank flows along the flow channel. When it flows to the water filling tank, the water body impacts the blades on the impact impeller and drives the impeller to rotate. After the water body impacts the impeller, the kinetic energy of the water body weakens, and under the influence of gravity, it flows downward to the water guide plate and enters the crack along the spring rope and the milling cutter head to simulate the situation where rainwater remains in the rock crack to form a water-containing rock mass in reality. At this time, spray a developer on the crack surface through a drone;

[0027] S6. At the same time, when the impeller rotates, it winds the connecting rope around the middle of the impeller and drives the piston to move upward, thereby pumping the liquid in the water storage bag into the water storage cylinder through the hose. At this time, the axial pressure exerted by the water storage bag on the explosive and the return spring decays linearly;

[0028] S7. After the pressure of the water storage bag on the explosive weakens, the return spring in the fixed cylinder undergoes elastic recovery and drives the air spacer layer between the explosives to gradually increase, so that the thickness of the air spacer layer in the PVC straight pipe can be adaptively adjusted according to the size of the water body entering the crack, making the thickness of the air spacer layer match the volume of the water body entering the crack;

[0029] S8. After the explosion, the probe converts the physical quantity of vibration into an electrical signal, records the detected vibration speed and frequency parameters. By changing the rock mass, changing the size of the groove through the grooving component, and re-changing the volume of the water body for multiple experiments, respectively obtain the distribution of the exploded rock blocks around the crack when the volume of the water body in the crack is different, and the dynamic strength of the rock mass and the propagation characteristics of the stress wave in the rock mass when the rock mass contains water in the crack.

[0030] The explanations of the nouns, conjunctions or adjectives involved in the above technical solutions are as follows:

[0031] Fixed connection means that after the parts or components are fixed, there is no relative movement connection;

[0032] Rotational connection means that the connection between parts allows the parts to rotate relative to each other;

[0033] Threaded connection is a detachable fixed connection, which has the advantages of simple structure, reliable connection, convenient installation and disassembly, etc., and is widely used in the fields of mechanical engineering and connection structures;

[0034] Sliding connection means that the connection between parts allows the parts to slide relative to each other.

[0035] The beneficial effects of the present disclosure:

[0036] Before the air layer interval between explosives is installed at the point to be detonated, the position of the air interval layer is unified. When injecting water into the water-containing fractured rock mass, the kinetic energy of water injection is used as the driving source, and the passive adjustment of the air layer spacing is realized through the hydrodynamic characteristics, so that the displacement of the air layer forms a dynamic balance with the water injection volume. When the experimenter remotely controls the size of the water body in the water-containing fractured rock mass, the size of the air interval layer in the PVC pipe can be adaptively adjusted according to the size of the water body to reduce the safety hazards of manual adjustment. Brief Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 is the overall structural schematic diagram of the embodiment of the present disclosure;

[0039] Figure 2 is the overall structural schematic diagram of another perspective of the embodiment of the present disclosure;

[0040] Figure 3 is the overall structural schematic diagram of the impeller and interval adjustment assembly of the embodiment of the present disclosure;

[0041] Figure 4 is the Figure 3 internal sectional structural schematic diagram in;

[0042] Figure 5 is the overall structural schematic diagram of the PVC straight pipe of the embodiment of the present disclosure;

[0043] Figure 6 is the overall structural schematic diagram of the grooving assembly of the embodiment of the present disclosure;

[0044] Figure 7 is the connection schematic diagram of the grooving assembly and the electric telescopic rod of the embodiment of the present disclosure.

[0045] In the figure: 1, support frame; 2, support table; 21, water filling tank; 22, positioning hole; 211, water guide plate; 3, water tank; 4, flow channel; 5, impeller; 6, interval adjustment assembly; 61, water storage cylinder; 62, connecting rope; 63, piston; 64, water storage bag; 611, hose; 612, snap ring; 7, grooving assembly; 71, motor; 72, milling cutter head; 73, dust shield; 711, electric telescopic rod; 8, spring rope; 9, PVC straight pipe; 91, fixed cylinder; 92, limiting plate; 93, return spring; 94, support plate; 911, positioning groove; 912, clamping rod; 913, limiting protrusion; 10, air cylinder. Detailed implementation mode

[0046] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

[0047] Please refer to Figures 1 to 7 , a multi-field coupling sandstone mine blasting vibration simulation experimental device, including: a fluid driving mechanism and a spacing adjusting component 6 linked with the fluid driving mechanism;

[0048] The fluid driving mechanism includes a flow channel 4 communicated with a water tank 3 and an impeller 5 arranged in a water filling tank 21. The water body in the water tank 3 moves through the water filling tank 21 into the groove body opened in the rock mass to simulate the water body in the water-containing fractured rock mass under natural conditions;

[0049] The spacing adjusting component 6 includes a vertical water storage cylinder 61. A piston 63 in sealed sliding fit is arranged in the inner cavity of the water storage cylinder 61. The rotating shaft supporting the rotation of the impeller 5 is connected with the top of the piston 63 through a connecting rope 62;

[0050] A hose 611 connects the water storage cylinder 61 and the water storage bag 64. The bottom of the water storage bag 64 supports one end of a vertically placed PVC straight pipe 9 filled with explosives. The water storage bag 64 forms a vertical downward pressure load on the PVC straight pipe 9 through its own weight;

[0051] Elastic members are arranged between adjacent explosives in the PVC straight pipe 9, and the elastic members keep an air spacer layer formed between adjacent explosives;

[0052] The water flow impacts the impeller 5, and the impeller 5 rotates. The rotating shaft of the impeller 5 winds the connecting rope 62, and the connecting rope 62 pulls the piston 63 to move upward, so as to form a negative pressure between the water storage cylinder 61 and the water storage bag 64, and extract the water body in the water storage bag 64 through the hose 611, so that the weight of the water body in the water storage bag 64 is reduced. The pressure change of the water storage bag 64 on the PVC straight pipe 9 causes the elastic member in the PVC straight pipe 9 to generate axial elastic deformation, so that when the elastic member generates axial elastic deformation, the thickness of the air spacer layer will also change, thereby adjusting the thickness of the air spacer layer between adjacent explosives in real time, so that the blasting vibration generated by the two explosives is within a preset range, and at this time, the thickness of the air spacer layer that can make the explosives explode within the preset range is a reasonable range.

[0053] During use, fill the water storage cylinder 61 and the water storage bag 64 with clean water or damping liquid. Initially, the lower end face of the piston 63 fits against the inner wall of the bottom end of the water storage cylinder 61. At this time, the elastic member is in a compressed state, and the air spacer between the explosives is 15 cm. Then, use a drilling machine to open a slot hole directly below the water storage cylinder 61. Next, coaxially install the PVC straight pipe 9 with the water storage cylinder 61. At the same time, an airtight fit is formed between the outer wall of the piston 63 and the inner wall of the water storage cylinder 61, and the piston 63 divides the water storage cylinder 61 into upper and lower ends. When the piston 63 moves upward, the volume of the bottom space of the water storage cylinder 61 increases, and the gas pressure inside the water storage cylinder 61 will decrease accordingly. According to the principle of atmospheric pressure, the external atmospheric pressure is greater than the air pressure inside the water storage cylinder 61. Therefore, under the action of the external atmospheric pressure, the liquid will be pressed from the water storage bag into the water storage cylinder. This structure is similar to the principle of a syringe for injection to suck water, and the hose 611 is similar to the injection head of a syringe. The bottom surface of the water storage bag 64 fits against the PVC straight pipe 9. After the water storage bag 64 is filled with water, the PVC straight pipe 9 is compressed to the minimum value by the water in the water storage bag 64, and at this time, the air spacer inside the PVC straight pipe 9 is the smallest;

[0054] A water pump is installed at the connection between the water tank 3 and the flow channel 4 to control the water flow rate through the water pump. The water pump is a Wilo PVME series variable frequency pump: it can automatically adjust the rotation speed according to the actual water use situation to change the flow rate. Its model is PVME20-6. Control the water flow rate in the flow channel 4 through the water pump. The volume of the water body can be controlled by the water flow rate and the outflow time. At the same time, by controlling the water flow rate, the rotation speed of the impeller 5 and the upward movement amount of the piston 63 can be changed. An elastic member with an appropriate elastic deformation ability is set so that when the liquid in the water storage bag 64 is pumped out, the displacement amount of the elastic member's restoration matches the water flow rate, so that when the increased volume of the water body injected into the crack matches the elongation displacement amount of the elastic member. That is, when 1 L of water body is injected into the crack, 100 ml of the liquid in the water storage bag 64 is pumped out, the elastic member restores 1-2 cm, and the increase amount of the air spacer between the explosives is 2 cm. At this time, the air spacer between the explosives is within a reasonable range, that is, for every 1 L increase in the water body, the air spacer increases by 1-2 cm. The reasonable range means that after 1 L of water body is added at the crack, the thickness of the air spacer adjustment can ensure that the power of the explosive explosion can explode the rock blocks around the water body and cause less damage to the surrounding rock mass and buildings. During this adjustment process, the thickness of the air spacer is adapted to the volume of the water body entering the crack. At the same time, in the actual scenario, the reasonable range will change according to the distance between the rock mass and the surrounding environment and the distance between the crack and the explosive. At this time, adjust its water flow rate according to the water pump, and an elastic member with an appropriate length and rigidity coefficient to meet the requirements;

[0055] Even when the volume of water in the crack is less than the originally planned experimental water volume, and the thickness of the air spacer layer is greater than the predetermined thickness when the originally planned experimental water volume, the energy buffering force of the water during the explosion is small at this time, causing the explosion stress to concentrate after the explosion and damage the surrounding rock mass and buildings. If the air spacer layer is preset when the water in the crack is the least, after the water volume increases, it is difficult for the energy after blasting to penetrate the water in the crack, easily leading to incomplete blasting, making the explosion fragments around the crack water less obvious. If it is too small, it will increase the safety risk, and the rock mass structure is unstable after excavation. Manually adjusting the air layer interval between explosives is prone to safety hazards. The reasonable range of the air spacer layer between explosives is between 15 - 18 cm when the water volume is 1 L. At the same time, if the distance between the blast hole and the crack at the site is too far or too close, the thickness of the air spacer layer can be adaptively improved according to the explosion power of the explosive, and the water flow velocity in the flow channel 4 is made greater than the gravity of the piston 63, which can push the impeller 5 to drive the piston 63 to move upward. Then, a crack is excavated and formed at the upper end of the rock mass. At this time, the water pump is started, and the water in the water tank 3 flows along the flow channel 4. When it moves to the water filling tank 21, the water impacts the blades on the impeller 5 and drives the impeller 5 to rotate. After the water impacts the impeller 5, the kinetic energy of the water weakens and enters the rock mass crack under the influence of gravity, filling the crack with water to simulate the situation where rainwater remains in the rock mass crack to form a water-containing rock mass in the actual situation;

[0056] However, while the impeller 5 rotates, it drives the connecting rope 62 to wind around the middle of the impeller 5, and drives the piston 63 to move vertically upward along the inner wall of the water storage cylinder 61, thereby forming a negative pressure space at the bottom of the water storage cylinder 61, and pumping the water in the water storage bag 64 upward into the water storage cylinder 61 through the hose 611. At this time, the axial pressure exerted by the water storage bag 64 on the PVC straight pipe 9 decays linearly, and a dynamic pressure regulation model is constructed, enabling the experimenter to passively and precisely regulate the air spacer in the PVC straight pipe 9 by controlling the water outflow volume, so that the displacement of the air spacer forms a dynamic balance with the water injection volume. When the crack is filled with gravel during the excavation process, the water storage volume in the crack changes. To make the water volume match the air spacer in the PVC straight pipe 9, the PVC straight pipe 9 needs to be adjusted again to change the air spacer after the water is poured in. However, for the excavated rock mass, the stability of the rock mass itself decreases. At this time, if climbing onto the rock mass to take out or install the PVC straight pipe 9, safety hazards are likely to occur. Moreover, if the experimenter climbs onto the rock mass on one side of the crack, it is easy to separate the entire rock mass at the crack, causing the rock mass crack to increase and the water in the crack to flow to the bottom, resulting in experimental errors. In addition, the impact force exerted by the explosive on the interval adjustment component 6 after the explosion will be absorbed by the water in the water storage cylinder 61, which is beneficial to protecting the interval adjustment component 6 after a single explosion and increasing the service life of the interval adjustment component 6. The water stored in the water storage cylinder 61 can be injected back into the water storage bag 64 again, facilitating recycling and saving water. At the same time, if the explosion intensity is relatively large, the water in the water storage cylinder 61 can be replaced with damping fluid. The molecular chains of the high molecular polymers inside the damping fluid undergo reversible deformation under shear stress, converting mechanical energy into heat energy, which can improve the buffering effect compared to water. At the same time, the interval adjustment component 6 has a simple structure and fewer rigid structures, effectively avoiding brittle fractures caused by stress concentration in traditional rigid components.

[0057] Please refer to Figures 1 to 2 , the impeller 5 is fixed inside the flushing tank 21 through an impeller bracket. The rotation axis of the impeller 5 is perpendicular to the water flow direction. The water flow flowing out from the flow channel 4 contacts the blades at the bottom of the impeller 5 and drives the impeller 5 to rotate counterclockwise. During use, the water flowing out through the flow channel 4 impacts the blades at the bottom of the impeller 5 and drives the bottom blades to move away from the flow channel 4, thereby causing the impeller 5 to rotate counterclockwise along the rotation axis.

[0058] Please refer to Figures 1 to 2 , a positioning hole 22 penetrating the support platform 2 is provided between the water tank 3 and the flushing tank 21, and a cylinder 10 is disposed through the inside of the positioning hole 22. A grooving component 7 is provided at the lower end of the cylinder 10. During use, the output end of the cylinder 10 is disposed through the positioning hole 22, and the grooving component 7 is fixed at the lower end of the cylinder 10. The position of the grooving component 7 is changed by the extension and shortening of the cylinder 10, and the volume of the grooved body is changed.

[0059] A water guide plate 211 is fixed to the lower end of the water filling tank 21, a grooving assembly 7 is fixed to the lower end of the air cylinder 10, and a spring rope 8 is fixed between the grooving assembly 7 and the water guide plate 211. The water body that has lost its kinetic energy falls above the water guide plate 211 under the influence of gravity and moves along the spring rope 8 to the side wall of the grooving assembly 7, keeping the grooving assembly 7 moist, which is beneficial to significantly reducing mechanical wear. And the grooving assembly 7 is located directly below the crack, so that the water body flowing along the grooving assembly 7 can accurately flow into the crack, which is beneficial to restricting the movement route of the water body and making the water body infiltrate along the axis of the rock mass crack. And by setting the spring rope 8 and using the characteristic that the spring rope 8 can freely expand and contract, when the grooving assembly 7 moves up and down, the spring rope 8 can elongate and deform as the grooving assembly 7 moves up and down, so as to prevent the spring rope 8 from being broken.

[0060] Please refer to Figure 6 and Figure 7 As shown in, the grooving assembly 7 includes a motor 71, a milling cutter disc 72 and a dust shield 73. The motor 71 is fixed to the lower end of the air cylinder 10, the output end of the motor 71 is fixed with the milling cutter disc 72, a dust shield 73 is coaxially fixed to the outside of the milling cutter disc 72, and one side of the spring rope 8 away from the water guide plate 211 is fixedly connected to the dust shield 73.

[0061] During use, the air cylinder 10 drives the milling cutter disc 72 to move up and down, and the bottom of the milling cutter disc 72 is a sharp end. The motor 71 drives the milling cutter disc 72 to rotate at a high speed. By using the friction and shearing action when the milling cutter disc 72 rotates, cracks are generated on the upper end surface of the rock mass and gradually cut, and a relatively regular notch is cut in the original complete rock mass sample, so that the notch can store water, to simulate the water-containing rock mass formed by rainwater stored inside the rock mass in the natural environment. At the same time, by controlling the descending height of the milling cutter disc 72, the size of the crack and the volume of water that can be accommodated in the crack can be adjusted.

[0062] One end of the electric motor 71 away from the milling cutter head 72 is fixed with an electric telescopic rod 711. The upper end surface of the electric motor 71 is fixed with a slider 712, and the upper end of the slider 712 is fixedly connected to the lower end of the air cylinder 10. Moreover, the moving path of the slider 712 is parallel to the moving path of the electric telescopic rod 711. When it is necessary to change the width of the crack, drive the electric telescopic rod 711, drive the grooving assembly 7 to move horizontally through the electric telescopic rod 711, and then change the width of the crack. When studying the relationship between the position of the water body and the in-situ stress field in the rock mass, the width of the crack can be changed by shortening the inward contraction length of the electric telescopic rod 711. At this time, when the water body is poured on the inner side of the crack, the center of gravity of the water body is in the middle of the rock mass. As the inward contraction distance of the electric telescopic rod 711 increases, the width of the crack within the same height increases. When the same volume of water body is poured on the inner side of the crack, the center of gravity of the water body is located in the upper part of the rock mass, which is conducive to providing programmable experimental conditions for studying the coupling relationship between different seepage positions and the rock mass stress field.

[0063] Please refer to Figures 3 to 5 , the PVC straight pipe 9 includes a fixed cylinder 91, a limit plate 92, a return spring 93 and a support plate 94. The lower end of the water storage cylinder 61 is clamped with the fixed cylinder 91. Moreover, a limit plate 92 is slidably arranged inside the fixed cylinder 91. The lower end surface of the limit plate 92 is fixed with a return spring 93, and the bottom of the return spring 93 is fixed with a support plate 94. The space supported by the return spring 93 between the limit plate 92 and the support plate 94 is an air spacer layer. Moreover, a plurality of explosives are arranged inside the fixed cylinder 91, and the explosives are respectively arranged on both sides of the air spacer layer. The return spring 93 is made of natural rubber material, with a thickness of 1-2 cm, a length of 35-40 cm, and a rigidity coefficient of 50-100 N / mm. In the initial state, the return spring 93 is compressed by 15 cm under the pressure of the explosives, the water storage bag 64 and the water body inside the water storage bag 64. As the liquid in the water storage bag 64 is pumped out, the return spring 93 is gradually restored.

[0064] When in use, the explosive is placed on the inner side of the fixed tube 91, and the bottom of the explosive is fitted with the upper end surface of the limiting plate 92, and then multiple fixed tubes 91 are coaxially clamped and arranged, and the lower end surface of the support plate 94 on the upper fixed tube 91 is fitted with the upper end surface of the explosive in the fixed tube 91 below it, and multiple air gaps are formed between the multiple explosives by the elastic supporting force of the return spring 93. When the explosive at the top is squeezed by the gravity of the water storage bag 64, the multiple explosive limiting plates 92 and the supporting plate 94 slide downward, thereby changing the size of the air gap layer inside the explosive. At the same time, when the water flows out, the impeller 5 drives the connecting rope 62 and the piston 63 to move upward. During the upward movement of the piston 63, the liquid in the water bag 64 is pumped into the water cylinder 61, so that the weight of the water bag 64 is gradually reduced. At the same time, the pressure of the water bag 64 on the explosive is gradually reduced, so that the multiple return springs 93 gradually recover elastically, thereby increasing the thickness of the air gap formed by the return springs 93. The weight change of the water bag 64 is converted into the elastic potential energy of the return springs 93 through the mechanical transmission of the impeller 5 and the piston 63, so that the thickness of the air gap layer changes with the water injection amount and matches the explosive energy release demand in real time.

[0065] Please refer to Figure 4 and Figure 5 A positioning groove 911 is formed at the upper end of the fixing cylinder 91, and a locking rod 912 that matches the positioning groove 911 is fixed to the bottom of the fixing cylinder 91. During assembly, the locking rods 912 of multiple fixing cylinders 91 are inserted into the positioning groove 911 in the adjacent lower fixing cylinder 91. A protrusion is fixed on the side of the bottom end of the locking rod 912 close to the axis of the fixing cylinder 91. When the two end surfaces of the two adjacent fixing cylinders 91 are in contact, the protrusion of the locking rod 912 is just inserted into the appropriate position of the bottom of the positioning groove 911. The multiple fixing cylinders 91 are assembled at the same time.

[0066] A retaining ring 612 is fixed to the bottom of the water storage cylinder 61, and a stopper protrusion 913 that mates with the retaining ring 612 is fixed to the outer wall of the uppermost fixed cylinder 91. When the fixed cylinder 91 explodes, the impact force of the explosion drives the retaining ring 612 upward, causing the stopper protrusion 913 to be offset from the retaining ring 612. As the explosives explode, the impact force of the explosion simultaneously drives the retaining ring 612 upward, separating the uppermost fixed cylinder 91 from the water storage cylinder 61, thereby protecting the integrity of the interval adjustment assembly 6.

[0067] The following further describes the multi-field coupled sandstone mine blasting vibration simulation experimental device and experimental method provided by the present invention in conjunction with the accompanying drawings and implementation examples.

[0068] S1. Prepare standard rock samples. First, make multiple complete rock samples according to the hardness of the sandstone. Then, make cylindrical rock specimens with the same hardness as the sandstone. Use a compressor to measure the load when the rock fails and calculate the point load strength.

[0069] S2. Place the explosives in a roll shape vertically into the fixed tube 91, with the upper and lower ends of the explosives respectively fitting against the support plate 94 and the limit plate 92. The space between the support plate 94 and the limit plate 92 between two adjacent explosives is the air gap layer;

[0070] S3. Place a suitable rock mass on the inner side of the support frame 1, and place the predetermined crack position corresponding to the milling cutter disc 72 in the upper and lower directions. Start the motor 71 to drive the milling cutter disc 72 to rotate at high speed, and then start the cylinder 10. The cylinder 10 drives the milling cutter disc 72 to move vertically downward until the milling cutter disc 72 contacts the rock mass and cuts the inner side of the rock mass. Grooves are made on the surface of the rock mass to simulate cracks in water-containing cracked rock mass under natural conditions. Blast holes are opened around the cracks using a drilling machine. A probe connected to the blasting vibrator is fixed to the ground near the rock, and the instrument is started before blasting.

[0071] S4. The PVC straight tube 9 with explosives is placed inside the blasthole, with the upper end of the PVC straight tube 9 located directly below the water storage cylinder 61. The water storage bag 64 applies downward pressure to the explosives and the return spring 93, so that the return spring 93 is in a compressed state and the air gap between adjacent explosives is minimized.

[0072] S5. The water pump outside the water tank 3 is started, causing the water in the water tank 3 to flow along the flow channel 4. When the water reaches the water trough 21, the water impacts the blades on the impeller 5, driving the impeller 5 to rotate. After the water impacts the impeller 5, its kinetic energy is weakened, and under the influence of gravity, it flows downward to the water guide plate 211 and enters the crack along the spring rope 8 and the milling cutter disc 72, simulating the formation of water-bearing rock mass caused by rainwater remaining in the rock crack in real conditions. At this time, a developer is sprayed on the crack surface by the drone.

[0073] S6. When the impeller 5 rotates, the connecting rope 62 is wound around the middle of the impeller 5, and the piston 63 is driven to move upward, thereby pumping the liquid in the water bag 64 into the water storage cylinder 61 through the hose 611. At this time, the axial pressure exerted by the water bag 64 on the explosive and the return spring 93 decays linearly.

[0074] S7. After the pressure of the water bag 64 on the explosives is reduced, the return spring 93 in the fixed tube 91 elastically recovers and causes the air gap between the explosives to gradually increase, so that the thickness of the air gap in the PVC straight tube 9 can be adaptively adjusted according to the size of the water entering the crack, so that the thickness of the air gap is adapted to the volume of the water entering the crack.

[0075] S8. After the explosion ends, the probe converts the physical quantity of vibration into an electrical signal, records the detected vibration speed and frequency parameters, changes the rock mass, changes the size of the groove body by changing the grooving component 7, and replaces the water volume again to conduct multiple experiments, respectively obtaining the distribution of the exploded rock blocks around the crack when the water volume in the crack is different, as well as the dynamic strength of the rock mass and the propagation characteristics of the stress wave in the rock mass when the rock mass crack contains water.

[0076] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0077] The above shows and describes the basic principles, main features and advantages of the present disclosure. Those skilled in the art of this industry should understand that the present disclosure is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure will have various changes and improvements, and these changes and improvements all fall within the scope of the present disclosure claimed.

Claims

1. Multi-field coupling sandstone mine blasting vibration simulation experimental device, characterized in that Comprising: A fluid driving mechanism and a spacing adjustment assembly (6) linked to the fluid driving mechanism; The fluid driving mechanism includes a flow channel (4) communicating with the water tank (3) and an impeller (5) disposed in the water filling tank (21). Starting the water pump outside the water tank (3) causes the water in the water tank (3) to flow along the flow channel (4). When it flows to the water filling tank (21), the water body impacts the blades on the impeller (5) and drives the impeller (5) to rotate. After the water body impacts the impeller (5), the kinetic energy of the water body weakens, and under the influence of gravity, it flows downward to the water guide plate (211) and enters the crack along the spring rope (8) and the milling cutter disc (72) to simulate the situation where rainwater remains in the rock crack to form a water-containing rock mass in reality; The spacing adjustment assembly (6) includes a vertical water storage cylinder (61). A piston (63) in sealed sliding fit is provided in the inner cavity of the water storage cylinder (61). The rotating shaft supporting the rotation of the impeller (5) is connected to the top of the piston (63) through a connecting rope (62); A hose (611) connects the water storage cylinder (61) and the water storage bag (64), and the bottom of the water storage bag (64) supports one end of a vertically placed PVC straight pipe (9) filled with explosives. The water storage bag (64) forms a vertically downward pressure load on the PVC straight pipe (9) by its own weight; An elastic member is provided between adjacent explosives in the PVC straight pipe (9), and the elastic member keeps an air spacer layer formed between adjacent explosives; The water flow impacts the impeller (5), and the impeller (5) rotates. The rotating shaft of the impeller (5) winds the connecting rope (62), and the connecting rope (62) pulls the piston (63) upward, creating a negative pressure between the water storage cylinder (61) and the water storage bag (64), and extracting the water body in the water storage bag (64) through the hose (611), reducing the weight of the water body in the water storage bag (64). The pressure change of the water storage bag (64) on the PVC straight pipe (9) causes the elastic member in the PVC straight pipe (9) to generate an axial elastic deformation, so that when the elastic member generates an axial elastic deformation, the thickness of the air spacer layer also changes, thereby adjusting the thickness of the air spacer layer between adjacent explosives in real time, making the blasting vibrations generated by the two explosives within a preset range.

2. The multi-field coupling sandstone mine blasting vibration simulation experimental device according to claim 1, characterized in that, The impeller (5) is fixed inside the water filling tank (21) through an impeller bracket. The rotating shaft of the impeller (5) is perpendicular to the water flow direction. The water flow flowing out of the flow channel (4) contacts the blades at the bottom of the impeller (5) and drives the impeller (5) to rotate counterclockwise.

3. The multi-field coupled sandstone mine blasting vibration simulation experiment device according to claim 2, wherein A positioning hole (22) penetrating the support platform (2) is provided between the water tank (3) and the water filling tank (21), and a cylinder (10) is disposed through the inside of the positioning hole (22). A grooving assembly (7) is provided at the lower end of the cylinder (10).

4. The multi-field coupling sandstone mine blasting vibration simulation experimental device according to claim 3, characterized in that A water guide plate (211) is fixed at the lower end of the water filling tank (21), and a spring rope (8) is fixed between the grooving assembly (7) and the water guide plate (211).

5. The multi-field coupling sandstone mine blasting vibration simulation experimental device according to claim 4, characterized in that, The grooving assembly (7) includes a motor (71), a milling cutter disc (72) and a dust shield (73). The lower end of the cylinder (10) is fixed with the motor (71), and the output end of the motor (71) is fixed with the milling cutter disc (72). The dust shield (73) is coaxially fixed on the outer side of the milling cutter disc (72), and one side of the spring rope (8) away from the water guide plate (211) is fixedly connected with the dust shield (73).

6. The multi-field coupling sandstone mine blasting vibration simulation experimental device according to claim 5, characterized in that, One end of the motor (71) away from the milling cutter disc (72) is fixed with an electric telescopic rod (711). The upper end surface of the motor (71) is fixed with a slider (712), and the upper end of the slider (712) is fixedly connected with the lower end of the cylinder (10). And the moving path of the slider (712) is parallel to the moving path of the electric telescopic rod (711).

7. The multi-field coupling sandstone mine blasting vibration simulation experimental device according to claim 6, characterized in that, The PVC straight pipe (9) includes a fixing cylinder (91), a limiting plate (92), a return spring (93) and a support plate (94). The lower end of the water storage cylinder (61) is clamped with the fixing cylinder (91), and the limiting plate (92) is slidably arranged inside the fixing cylinder (91). The lower end surface of the limiting plate (92) is fixed with the return spring (93). The elastic member is the return spring (93), and the bottom of the return spring (93) is fixed with the support plate (94). The space supported by the return spring (93) between the limiting plate (92) and the support plate (94) is an air spacer layer. And a plurality of explosives are placed inside the fixing cylinder (91), and the explosives are respectively placed on both sides of the air spacer layer. The material of the return spring (93) is natural rubber material, and the thickness is 1 - 2 cm.

8. The multi-field coupling sandstone mine blasting vibration simulation experimental device according to claim 7, characterized in that, The upper end of the fixing cylinder (91) is provided with a positioning groove (911), and the bottom of the fixing cylinder (91) is fixed with a clamping rod (912) adapted to the positioning groove (911).

9. The multi-field coupled sandstone mine blasting vibration simulation experimental device according to claim 8, characterized in that, The bottom of the water storage cylinder (61) is fixed with a snap ring (612), and the outer wall of the uppermost fixing cylinder (91) is fixed with a limiting projection (913) adapted to the snap ring (612).

10. The experimental method of the multi-field coupling sandstone mine blasting vibration simulation experiment, using the multi-field coupling sandstone mine blasting vibration simulation experimental device described in claim 9, characterized in that, It includes the following steps: S1. Prepare standard rock samples. First, make a plurality of complete rock mass samples according to the sandstone hardness, and then make cylindrical rock specimens with the same hardness as the sandstone. Measure the load when the rock is damaged by a compressor, and calculate the point load strength; S2. Vertically place the explosives into the fixing cylinder (91) in a roll shape. The upper and lower ends of the explosives are respectively attached to the support plate (94) and the limiting plate (92). The interval between the support plate (94) and the limiting plate (92) between adjacent two explosives is the air spacer layer; S3. Place a suitable rock mass on the inner side of the support frame (1), and place the predetermined crack position corresponding to the milling disc (72) above and below, start the motor (71) to drive the milling disc (72) to rotate at high speed, and then start the cylinder (10). The cylinder (10) drives the milling disc (72) to move vertically downward until the milling disc (72) contacts the rock mass and cuts the inner side of the rock mass, grooves are cut on the surface of the rock mass to simulate the cracks of the water-containing cracked rock mass in the natural state, and blast holes are opened around the cracks by a drilling machine. A probe connected to the blasting vibrator is fixed on the ground near the rock, and the instrument is started before blasting; S4. At this time, the PVC straight tube (9) with explosives is placed inside the blasthole, and the upper end of the PVC straight tube (9) is located directly below the water storage cylinder (61), and the water storage bag (64) applies downward pressure to the explosives and the return spring (93), so that the return spring (93) is in a compressed state and the air gap between adjacent explosives is minimized; S5. At this time, the water pump outside the water tank (3) is started, so that the water in the water tank (3) flows along the flow channel (4). When the water flows to the water trough (21), the water body impacts the blades on the impeller (5) and drives the impeller (5) to rotate. After the water body impacts the impeller (5), the kinetic energy of the water body is weakened, and under the influence of gravity, it flows downward to the water guide plate (211) and enters the crack along the spring rope (8) and the milling cutter disc (72) to simulate the rainwater remaining in the rock crack to form a water-containing rock mass under real conditions. At this time, the developer is sprayed on the crack surface by the drone; S6. When the impeller (5) rotates, the connecting rope (62) is wound around the middle of the impeller (5), and the piston (63) is driven to move upward, thereby drawing the liquid in the water storage bag (64) into the water storage cylinder (61) through the hose (611). At this time, the axial pressure exerted by the water storage bag (64) on the explosive and the return spring (93) is attenuated; S7. After the pressure of the water bag (64) on the explosive is reduced, the return spring (93) in the fixed cylinder (91) recovers elastically and drives the air gap layer between the explosives to gradually increase, so that the thickness of the air gap layer in the PVC straight tube (9) can be adaptively adjusted according to the size of the water entering the crack, so that the thickness of the air gap layer is adapted to the volume of the water entering the crack; S8. After the explosion, the physical quantity of the vibration is converted into an electrical signal through the probe, and the vibration speed and frequency parameters are recorded and detected. By replacing the rock mass, changing the slot size through the slot assembly (7), and re-changing the water volume, multiple experiments are conducted to obtain the distribution of the exploded rock blocks around the cracks when the water volume in the cracks is different, as well as the dynamic strength of the rock mass and the stress wave propagation characteristics in the rock mass when water is contained in the rock cracks.

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