Mine underground air return shaft and construction method thereof

Abstract

The invention belongs to the technical field of mining construction, and discloses a mine underground air return shaft and a construction method thereof.The air return shaft comprises a shaft, a connecting channel is arranged at the bottom of the shaft, and prefabricated walling cribs which are sequentially overlapped in the axial direction are arranged in the shaft; the space between the prefabricated well ring and the original rock of the shaft is filled with a wall back filling layer formed by slurry; according to the scheme, the prefabricated walling crib replaces a traditional underground cast-in-place walling crib, limitation of underground limited space on the pouring quality is avoided, and the installation construction period is shortened; then, slurry is filled between the prefabricated walling crib and the shaft original rock to form a wall back filling layer, and the combination stability of the walling crib and the surrounding rock is enhanced; the problem that when an existing mine underground air return shaft is constructed through a forward tunneling common method, the quality of a well ring poured in place is poor is solved.

Description

TECHNICAL FIELD

[0001] The present scheme belongs to the technical field of mine exploitation construction, and particularly relates to a mine underground return air shaft and a construction method thereof. BACKGROUND

[0002] The mine underground operation environment is relatively closed, and toxic and harmful gases such as gas and carbon monoxide are continuously generated in the exploitation process, accompanied by a large amount of dust, which not only seriously endangers the health of miners, but also may cause major safety accidents such as explosion and fire due to excessive gas concentration. Therefore, in order to ensure the safety of underground operation, the return air shaft has become an essential engineering facility in mine exploitation.

[0003] The mine underground return air shaft is a shaft drilled from the ground to the underground, which is specially used for returning air. It cooperates with the air intake shaft to form the ventilation system of the mine underground, and its role is to discharge the air, harmful gases and dust after use in the underground operation area to the ground, and at the same time, to continuously transport external air to each operation surface underground through the formation of air flow circulation, so as to maintain a good working environment underground.

[0004] From the construction point of view, there are two common structures for constructing return air shafts: one is to construct return air shaft by blasting operation, and the other is to reserve return air shaft in the stope. Among them, the return air shaft constructed by blasting operation is formed by forward excavation, blasting and breaking rock to form the shaft rudiment first, and then pouring and supporting the shaft wall with concrete. Personnel need to enter the shaft for operation during construction, which exists multiple damages to surrounding rock caused by blasting and safety risks, and the construction period is relatively long.

[0005] When the existing return air shaft is constructed by using the ordinary method of forward excavation, the shaft ring adopts the concrete structure poured on site underground. Due to the limitation of the limited space underground, the concrete is not fully vibrated and cured, and other problems such as poor quality defects such as honeycomb, pitted surface or insufficient strength are easy to occur. Moreover, the secondary blasting operation in the construction process will cause multiple damages to the surrounding rock structure and the poured concrete shaft ring, affecting the stability of the overall structure of the shaft. SUMMARY

[0006] The purpose of the present scheme is to provide a mine underground return air shaft to solve the problem of poor quality of the poured shaft ring on site when the existing mine underground return air shaft is constructed by using the ordinary method of forward excavation.

[0007] In order to achieve the above purpose, the present scheme provides a mine underground return air shaft, which comprises a shaft, a communication passage is arranged at the bottom of the shaft, and a prefabricated shaft ring is arranged in the shaft in an axial direction and overlapped sequentially, and a wall backfill layer formed by grout is filled between the prefabricated shaft ring and the original rock of the shaft.

[0008] The principle and effect of the scheme are that the prefabricated well ring is used to replace the traditional well site pouring well ring, the limitation of the limited space on the pouring quality is avoided, and the installation construction period is shortened.

[0009] Further, the prefabricated well ring is made of concrete, and the prefabricated well ring is provided with steel bars.

[0010] The principle and effect of the scheme are that the steel bars in the concrete prefabricated well ring are used to enhance the strength of the prefabricated well ring.

[0011] A mine underground return air shaft construction method comprises the following steps: Step S10: a communication passage is constructed at the upper and lower middle sections of the area where the return air shaft is to be constructed in the mine, and a floor is poured at the area where the return air shaft is located in the upper middle section communication passage; Step S20: a reverse well drilling machine is used to perform a reverse well operation on the floor, the drilling depth of the drill rod is measured according to the construction depth during the operation, an embryonic well shaft is formed, and yellow sand is poured into the well shaft until the well shaft is filled after the reverse well operation is completed; Step S30: a prefabricated well ring is poured with concrete, the diameter of the prefabricated well ring is determined according to the size of the well shaft, and the prefabricated well ring that meets the quality standard is transported to the return air shaft construction site in the mine for standby; Step S40: the prefabricated well ring is transported to the return air shaft construction site for standby, a winch and a pulley are installed above the well mouth of the upper middle section, the pulley is connected to the steel wire rope of the winch, then the prefabricated well ring is lowered along the center of the well shaft, the first prefabricated well ring is hoisted to the well mouth position, the yellow sand in the well is gradually discharged to make the well ring sink with the yellow sand, and the subsequent prefabricated well rings are continuously hoisted and stacked at the well mouth, and the process is repeated until the prefabricated well rings are stacked to the height of the preset well shaft; Step S50: concrete slurry is filled in the gap between the outer wall of the prefabricated well ring and the original rock of the well shaft; Step S60: after the concrete slurry is solidified and the well shaft is stable, the return air shaft well completion construction is completed.

[0012] The principle and effect of the scheme are that the reverse well drilling machine is used to form an embryonic well shaft, the drilling depth of the drill rod is measured to control the construction depth of the well shaft, the yellow sand is used to fill the well shaft to assist the prefabricated well ring to be hoisted and stacked by the winch and the pulley, and finally the concrete slurry is used to fix the well ring.

[0013] Further, in step S20, a measuring device is used to measure the drilling depth of the drill rod; the measuring device comprises: The clamping unit comprises a driving roller, clamping rollers and a rack, the driving roller and the clamping rollers are arranged on the rack, the number of the clamping rollers is two, the two clamping rollers are in a triangular distribution with the driving roller, and the clamping rollers are used for clamping the drill rod; A rotary encoder, an input shaft of the rotary encoder is coaxially fixedly connected with a rotating shaft of the driving roller; An identification strip, the identification strip is used for identifying the identification strip on the surface of the drill rod; A driving unit, the driving unit is used for driving the identification strip to identify the identification strip at intervals along the drill rod in the axial direction; The clamping unit comprises a driving roller, clamping rollers and a rack, the driving roller and the clamping rollers are arranged on the rack, the number of the clamping rollers is two, the two clamping rollers are in a triangular distribution with the driving roller, and the clamping rollers are used for clamping the drill rod; A camera, the camera is used for collecting an image of the identification strip and transmitting image information to a data processing module; The data processing module is used for receiving the image information and identifying the interval of adjacent identification strips in the detection image.

[0014] The principle and effect of the scheme are that (1) referring to the document with the existing publication (announcement) No. CN117967287A, a coal mine underground drilling depth re-measuring device and method are disclosed, the roller shaft is arranged along the transverse direction, the transverse one end of the roller shaft is rotatably installed in the support rod close to the transverse left side, the transverse other end of the roller shaft sequentially penetrates the support rod close to the transverse right side, the shell main body and the fixing seat, the transverse other end of the roller shaft is connected with the photoelectric encoder, the photoelectric encoder is arranged on the shell support plate, the shell support plate between the two photoelectric encoders is provided with an acquisition and controller mounting hole, an acquisition and controller is installed in the acquisition and controller mounting hole, and the acquisition and controller is connected with the photoelectric encoder, the jack and the strain gauge. The above measuring device adopts two photoelectric encoders to measure at the same time, the measurement results of the two can be verified with each other; meanwhile, when calculating the drilling depth, the depth data output by the two photoelectric encoders is averaged to make the calculation result more accurate. However, in the underground drilling rod hole turning construction site, there are a lot of flying coal dust and rock powder, which are easy to adhere to the surface of the drilling rod to form a dust layer, so that the roller is easy to slip in the rolling process. Once slipping, even if a plurality of photoelectric encoders are arranged, the number of pulses recorded by the photoelectric encoder cannot accurately reflect the actual displacement of the drilling rod, finally leading to the deviation of the measured data. (2) in the scheme, when the drilling rod advances, the driving roller is used to drive the rotation of the encoder input shaft, the rotary encoder converts the number of rotations of the driving roller into a pulse signal, and the drilling rod advancing length is calculated through the data processing module. At the same time, the driving unit drives the identification strip to move, and the identification strip is spaced along the axis of the drilling rod. The camera collects the image of the identification strip and transmits it to the data processing module. The data processing module detects the distance between adjacent identification strips through image recognition algorithm. Since the distance between the identification strips is set to be an integer multiple of the circumference of the driving roller, if the driving roller abnormally rotates due to the adhesion of rock powder or foreign matters on the surface of the drilling rod, the actual distance between the identification strips will deviate from the theoretical distance. The data processing module compares the distance deviation and triggers the alarm stop. After positioning the abnormal interval, the measurement accuracy is ensured by cleaning the foreign matters on the driving roller and correcting the data of the rotary encoder. (3) the scheme realizes basic measurement through the rotary encoder, and the identification strip and the camera are used for calibration and detection of the rotary encoder. The combination of the two solves the problem of abnormal rotation of the roller in the prior art and improves the accuracy of drilling depth measurement.

[0015] Further, the driving unit comprises a rotating disc coaxially fixedly connected with the driving roller, and the identification strip is arranged on the outer periphery of the rotating disc.

[0016] The principle and effect of the scheme are that when the drill rod drives the driving roller to rotate, the rotating disc and the identification strip rotate synchronously. The rotating disc drives the identification strip to contact the drill rod, and the identification strip is identified. When the identification strip moves away from the surface of the drill rod along with the rotating disc, the marking action is paused, so that the identification strip is marked at intervals along the axial direction of the drill rod. When the driving roller rotates normally, the rotating disc rotates one circle, the identification strip contacts the drill rod once along with the convex part, and the interval of the identification strip should be an integer multiple of the circumference of the driving roller (i.e. the theoretical interval). If the driving roller rotates abnormally, the actual number of rotations of the driving roller will be less (or greater) than the theoretical number of rotations corresponding to the actual travel distance of the drill rod, at this time, the number of rotations of the rotating disc is reduced (or increased) synchronously, resulting in that the actual interval of the identification strip is greater (or less) than the theoretical interval. Therefore, when the driving roller rotates abnormally, the rotating disc cannot drive the identification strip to act according to the theoretical number of rotations, and the interval of the identification strip will deviate from the theoretical value of "integer multiple of the circumference of the driving roller", and the camera can identify the abnormal state of the driving roller by detecting the interval deviation.

[0017] Further, the driving unit comprises a crank and a connecting rod, one end of the crank is fixedly connected with the driving roller coaxially, the free end of the crank is hingedly connected with the connecting rod, the free end of the connecting rod is hingedly connected with a sliding block, the sliding block is slidingly connected with the rack horizontally, the center of the sliding block is eccentrically arranged with the rotation center of the driving roller; one end of the sliding block close to the driving roller is connected with a lever, the identification strip is connected with a carrier plate, the carrier plate is connected with a support rod, the support rod is provided with a spring for resetting the support rod, the support rod is slidingly connected with a support, the support is fixedly arranged on the rack, and the free end of the lever is used for abutting against the free end of the support rod, so that the identification strip contacts the surface of the drill rod.

[0018] The principle and effect of the scheme are that: (1) when the driving roller rotates, the crank is driven to make a circular motion, thereby driving the slider to make a reciprocating linear motion through the connecting rod, and because the center line of the slider is eccentrically arranged with the rotation center of the driving roller, a biased crank slider structure is formed, so that the slider generates a quick return characteristic during reciprocating motion, that is, the speed of the slider is different when it goes back and forth, and the speed of the slider when it advances is lower than the speed when it returns. When the slider returns, the push rod moves synchronously, and the free end of the push rod and the free end of the supporting rod are in contact, so that the identification strip moves towards the drill rod; when the slider returns to the limit position of the return stroke, the push rod pushes the free end of the supporting rod to move, so that the identification strip is in contact with the surface of the drill rod and extrudes the marking material (such as fluorescent agent, etc.), leaving the identification strip on the surface of the drill rod; when the crank continues to rotate, the slider moves away from the limit position of the return stroke, and the spring drives the supporting rod to reset to the initial position, so that the identification strip moves away from the surface of the drill rod, and the marking action is paused. Because the crank completes a circular motion once, the slider completes a reciprocating motion and triggers a marking action once, so that the identification strip is marked on the drill rod at intervals along the axial direction. In this process, if the driving roller rotates normally, the spacing of the identification strips is the theoretical design value; if the driving roller rotates abnormally, the frequency of the reciprocating motion of the slider will be abnormal, so that the actual spacing of the identification strips deviates from the theoretical value, thereby detecting it.

[0019] Further, the free end of the push rod is provided with a pressing ball, and the free end of the supporting rod is provided with a pressed ball, the pressing ball and the pressed ball are oppositely arranged and used to contact each other.

[0020] The principle and effect of the scheme are that: through the cooperation of the pressing ball and the pressed ball, both of which are spherical structures, the free end of the push rod is convenient to push the free end of the supporting rod to move.

[0021] Further, the carrier plate is provided with an air bag, the air bag is provided with ink, the air bag is provided with a discharge port, one end of the discharge port is communicated with the inner cavity of the air bag, and the other end is communicated with the identification strip.

[0022] The principle and effect of the scheme are that when the carrier plate drives the identification strip to move to contact the surface of the drill rod, the air bag is first contacted with the surface of the drill rod, so that a part of the ink in the air bag is extruded onto the identification strip, and then the drill rod is marked, so that the identification strip is prevented from lacking ink after multiple markings.

[0023] Further, the rack is provided with a connecting rod, the connecting rod is provided with a horizontally arranged sleeve, a spray hole is formed in the side wall of the sleeve and communicated with the inner cavity of the sleeve, the gas outlet end of the spray hole faces the drill rod, the sliding block is slidably arranged in the sleeve and reciprocatingly linearly moves along the axial direction of the sleeve, and the sleeve is provided with a through groove for the movement of the connecting rod.

[0024] The principle and effect of the scheme are that when the sliding block moves to the direction of the spray hole during the working stroke, the sliding block compresses the gas in the sleeve after moving away from the through groove region, the gas is sprayed to the surface of the drill rod through the spray hole, so that the coal dust and rock powder on the surface of the drill rod are blown away, the driving roller is prevented from slipping, and the identification strip is facilitated to mark the surface of the drill rod.

[0025] Further, the center line of the spray hole is inclined to the advancing direction of the drill rod, so that the airflow sprayed by the spray hole forms an angle with the surface of the drill rod.

[0026] The principle and effect of the scheme are that before the identification strip contacts the drill rod, the inclined airflow is used to clean the to-be-marked region, so that the identification strip is more clearly attached to the surface of the drill rod.

[0027] Further, the end of the sliding block facing the spray hole is provided with a rubber plug, and the rubber plug is in interference fit with the inner wall of the sleeve.

[0028] The principle and effect of the scheme are that the rubber plug is arranged in cooperation with the sleeve, the sealing effect is better, the gas is prevented from leaking from the gap, and the gas in the sleeve is extruded. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structural schematic view of the reverse circulation drilling rig construction of the present application; Figure 2 It is a structural schematic view of the hoist construction of the present application; Figure 3 It is a structural schematic view of the prefabricated well circle construction loaded in the wellbore of the present application Figure 1 ; Figure 4 It is a structural schematic view of the prefabricated well circle construction loaded in the wellbore of the present application Figure 2 ; Figure 5 Structure diagram of the measuring device of the present application; Figure 6 Structure diagram of the driving assembly and the identification strip of the present application Figure 1 ; Figure 7 Structure diagram of the driving assembly and the identification strip of the present application Figure 2 ; Figure 8 Structure diagram of the internal structure of the sleeve of the present application.

[0030] The reference signs in the drawings of the specification include: shaft 1, communication passage 11, prefabricated well ring 2, filling layer 3, reverse drilling machine 4, drill rod 41, yellow sand 5, winch 6, pulley 61, steel wire rope 62, measuring device 7, identification strip 71, camera 72, driving roller 73, clamping roller 74, rack 75, rotating disc 76, crank 77, connecting rod 78, sliding block 79, push rod 710, carrier plate 711, support rod 712, spring 713, pressure applying ball 714, pressure receiving ball 715, connecting rod 716, sleeve 717, injection hole 718, through groove 719, rubber plug 720, air bag 721. DETAILED DESCRIPTION

[0031] The concept and the generated technical effects of the present application will be described clearly and completely in combination with the embodiments below, so as to fully understand the purpose, features and effects of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application: Embodiment one: Please refer to 1- Figure 4 The present application discloses a mine underground return air shaft, which comprises a shaft 1, a communication passage 11, a prefabricated well ring 2 and a wall back filling layer 3. The prefabricated well ring 2 is made of C40 fine stone concrete pouring, with an annular steel mesh inside. The steel mesh is interwoven by longitudinal steel bars with a diameter of 16 mm and circumferential steel bars with a diameter of 12 mm. The longitudinal steel bars have a spacing of 200 mm, and the circumferential steel bars have a spacing of 150 mm, forming a stable framework structure to improve the compressive strength and deformation resistance of the prefabricated well ring 2. The prefabricated well rings 2 are arranged in sequence along the shaft 1 in the axial direction, with the end faces of the adjacent prefabricated well rings 2 tightly fitted. Water-swelling sealing strips are arranged at the joints to ensure the sealing performance of the joints and prevent subsequent filling slurry from leaking. The wall back filling layer 3 is made of fine stone concrete slurry with a strength grade of C25. An appropriate amount of expanding agent is mixed into the slurry, with an expansion rate controlled within 0.02%-0.05%. The filling thickness is 100-150 mm. The prefabricated well ring 2 is firmly combined with the original rock of the shaft 1 through the hardening of the slurry, to transfer the load and enhance the overall stability of the shaft 1, avoiding the stress concentration caused by the gap between the well ring and the surrounding rock.

[0032] Example 2: Please continue reading. Figures 1-4 To better facilitate the construction of the aforementioned return air shaft, this invention also provides a construction method for underground return air shafts in mines, which is implemented according to the following steps: Step S10: Construct two connecting passages 11 in the upper and lower sections of the underground return air shaft area. Specifically, first, construct two connecting passages 11 in the upper and lower sections of the underground return air shaft area. The connecting passage 11 has a cross-sectional dimension of 2.5m × 2.8m (width × height), uses anchor-sprayed support, and employs C25 grade sprayed concrete to ensure sufficient load-bearing capacity and stability for subsequent equipment transportation and personnel access. Then, pour a 200mm thick C30 concrete slab in the area of ​​the upper connecting passage 11. Before pouring, clean the base layer of debris and moisten it with water. After pouring, cover with geotextile and water for curing for at least 3 days to ensure the slab can withstand the load impact during the operation of the raise boring machine 4. Step S20: A raisebore operation is performed on the ground using a raisebore drill rig 4. During the operation, the drilling depth of the drill rod 41 is measured according to the construction depth to form the initial shape of the well casing 1. After the raisebore is completed, yellow sand 5 is poured into the well casing until it is full. Specifically, an LM-250 type raisebore drill rig 4 is selected to perform a raisebore operation on the ground. The drill rod 41 of the raisebore drill rig 4 is a Φ127mm high-strength alloy steel drill rod with a single length of 3m. During the operation, a measuring device 7 is used to measure the drilling depth of the drill rod 41 in real time to control the construction depth of the initial shape of the well casing 1. After the raisebore is completed, medium-coarse sand with a particle size of 0.5-2.0mm is filled into the well casing 1 as yellow sand 5. During the filling process, a vibratory tamping rod is used to assist in compaction to ensure that the yellow sand 5 filling density is ≥95%, providing stable support for the subsequent hoisting of the precast well ring 2 and preventing tilting or damage during the lowering of the well ring.

[0033] Step S30: Cast the precast well ring 2 with concrete. The diameter of the precast well ring 2 is determined according to the size of the shaft 1. Then, transport the precast well ring 2 with qualified quality to the underground return air shaft construction site for standby. Specifically, the precast well ring 2 is formed by casting with a customized steel mold. The inner wall of the mold is coated with a release agent to facilitate subsequent demolding. The steel bar cage is pre-bonded and then placed in the mold, and then C40 concrete is poured. During the pouring process, an attached vibrator is used to vibrate densely to ensure that there are no defects such as honeycombs and pitted surfaces inside the concrete. The poured precast well ring 2 is cured for 28 days under standard curing conditions. During the curing period, water is sprinkled regularly to keep the surface moist. After curing, quality inspection is carried out. The inspection indicators include compressive strength, appearance size deviation, etc. Among them, the compressive strength ≥ 35 MPa is the qualified standard. The precast well ring 2 with qualified quality is transported to the underground return air shaft construction site by a special transport vehicle. During the transportation process, 50-mm-thick rubber soft pads are laid on the upper and lower ends of the well ring to avoid collision damage, and the transportation route is avoided from sharp obstacles.

[0034] Step S40: Transport the precast well ring to the return air shaft construction site for standby. Install a hoist 6 and a pulley 61 above the upper-middle section wellhead. Connect the pulley 61 through the steel wire rope 62 of the hoist 6, and then lower the precast well ring 2 along the center of the shaft 1. After hoisting the first precast well ring 2 to the wellhead position, gradually discharge the yellow sand in the well to make the well ring sink with the yellow sand. At the same time, continuously hoist the subsequent precast well rings 2 at the wellhead and stack them in sequence. Repeat this process until the precast well rings 2 are stacked to the preset height of the shaft 1. Specifically, install a hoist 6 above the upper-middle section wellhead, symmetrically arranged on both sides of the wellhead. Each hoist 6 is equipped with 1 fixed pulley 61 and 1 movable pulley 61. The steel wire rope 62 is made of high-strength galvanized steel wire rope. Connect the pulley 61 through the steel wire rope 62 of the hoist 6 to form a hoisting system, and then lower the precast well ring 2 along the center of the shaft 1. Before hoisting, install an annular guide frame (not shown) at the upper opening of the shaft 1 to ensure that the precast well ring 2 is lowered along the central axis to avoid deviation. After hoisting the first precast well ring 2 to the wellhead position, control the discharge speed of the yellow sand 5 through the discharge valve preset at the wellhead, which is controlled at 1.5 cubic meters per hour, so that the well ring sinks evenly with the yellow sand 5, and the sinking speed is maintained at 0.5 m / h to prevent the well ring from tilting due to too fast sinking. At the same time, continuously hoist the subsequent precast well rings 2 at the wellhead and stack them in sequence. When hoisting, use a laser locator to calibrate the verticality of the well ring to ensure that the axial deviation of the upper and lower well rings ≤ 3 mm. Repeat this process until the precast well rings 2 are stacked to the preset height of the shaft 1. The preset height is determined according to the mine ventilation requirements, generally 80 - 120 m.

[0035] Step S50: Fill the gap between the outer wall of the precast well ring 2 and the original rock of the well shaft 1 with concrete grout. C25 fine aggregate concrete grout is filled in the gap between the outer wall of the precast well ring 2 and the original rock of the well shaft 1. The grout mix ratio is cement:sand:aggregate:water = 1:1.5:2.5:0.45, with an appropriate amount of polycarboxylate-based high-efficiency water-reducing agent added. The slump is controlled at 120-140mm to ensure good fluidity and filling properties. Filling is done in sections, each 2m high, proceeding from bottom to top. An immersion vibrator is used for compaction during pouring, with a vibration time controlled at 20-30s per point. The grout height is monitored in real time during pouring to avoid missed or over-pouring.

[0036] Step S60: After the concrete slurry has solidified and the shaft 1 is stable, the return air shaft construction is completed. After the concrete slurry is poured, it is cured by water spraying for no less than 7 days. During the curing period, the surface of the slurry is kept moist to avoid cracking due to excessive evaporation of moisture. After curing, the stability of the shaft 1 is tested. The radial displacement of the shaft 1 is measured using an inclinometer. A displacement of ≤5mm is considered acceptable. At the same time, the bonding strength between the backfill layer 3 and the precast well ring 2 and the original rock is tested. The bonding strength is ≥1.5MPa. Once the above requirements are met, the return air shaft construction is completed.

[0037] Example 3: Please see Figure 5 and Figure 6 This embodiment provides a measuring device 7, which comprises a clamping unit, a rotary encoder 8, an identification strip 71, a drive unit, a camera 71, and a data processing module. The clamping unit includes a drive roller 73, a clamping roller 74, and a frame 75. Both the drive roller 73 and the clamping roller 74 are made of wear-resistant alloy material, and their surfaces are textured with anti-slip patterns to enhance friction with the drill rod 41 and reduce slippage. The two clamping rollers 74 are arranged in a 120° triangle with the drive roller 73, thus stably clamping the outer wall of the drill rod 41. The rotary encoder 8 is an Omron encoder of model E6B2-CWZ6C with a resolution of 1000 lines. The encoder is configured to accumulate pulses clockwise, but not counterclockwise, and does not accumulate or decrease pulses. The input shaft of the rotary encoder 8 is coaxially fixed to the rotating shaft of the drive roller 73 via a coupling, allowing the rotary encoder 8 to synchronously acquire rotation signals when the drive roller 73 rotates. The marking strip 71 is a foam structure with a height of 1 cm. Its end face can be used to absorb fluorescent marking ink. In this embodiment, red fast-drying fluorescent ink is used. When the marking strip 71 is pressed, the marking ink is pressed onto the surface of the drill rod 4 to form the marking strip (e.g., ...). Figure 6(As shown in the diagram); Camera 72 is a CCD camera, fixedly mounted at the rear end of drive roller 73 via an adjustable bracket. To expand the camera's field of view to simultaneously capture two adjacent marker strips, camera 72 is tilted +60° along the axial direction of drill rod 41, with the mirror surface maintaining a certain distance from the surface of drill rod 41, for example, 5cm. The camera 72 acquires marker strip images and transmits them to the data processing module. The data processing module used in this embodiment is existing technology. For example, it employs embedded industrial control, interacting with camera 72 in real-time via the GigEVision protocol. Shielded twisted-pair cables are used to transmit marker strip images at a resolution of 1280×1024 and a frame rate of 60fps. A built-in chip performs median filtering and adaptive binarization on the images to eliminate coal dust noise and highlight fluorescent marker strips. Simultaneously, it receives A / B phase pulse signals from rotary encoder 21 via a differential encoder interface, accumulates the pulse count in real-time using a 16-bit hardware counter, and communicates with the drilling rig controller via the PROFINET bus to ensure that stop commands are transmitted to the drilling rig controller. At the software level, the edges of the marker strips are extracted using the Canny operator and Hough transform, the axial spacing between adjacent marker strips is calculated, and the measured spacing is compared with the theoretical value (determined by the circumference C of the measuring roller and the marking frequency, such as a theoretical spacing of 78.5 mm when C=314 mm). When the deviation value ΔL exceeds 5%, the error data range is located by mapping the marker strip number to the encoder pulse (such as the nth marker strip corresponding to n×(P / 4) pulses, P=1024), and an audible and visual alarm is triggered. The reverse drilling rig 4 is then stopped. Work can only continue after the staff cleans the foreign objects on the surface of the drive roller 73 or corrects the data of the rotary encoder 8.

[0038] Please continue reading. Figure 6 In this embodiment, the drive unit includes a turntable 76, which is connected to the drive roller 73 shaft via a flat key. A rectangular protrusion is provided on the outer periphery of the turntable 76, and an identification strip 71 is pasted onto the end face of the protrusion. The protrusion is 10mm high. When the turntable 76 rotates with the drive roller 73, the protrusion causes the identification strip 71 to periodically contact the drill rod 41, forming intermittent markings. Each time the drive roller 73 rotates once, the identification strip 71 completes one marking action. Figure 6 As shown, the spacing between the two marker strips L1 and L2 is the spacing during normal rotation of the drive roller 73. The spacing between L1 and L2 is the circumference of one revolution of the drive roller 73, and the number of pulses for one revolution of the drive roller 73 is accumulated by the rotary encoder 8. The spacing between L2 and L3 is the spacing during abnormal rotation of the drive roller 73. When the camera 72 captures the marker strips L2 and L3 and transmits the image to the data processing unit, the abnormal state of the drive roller 73 is identified when this spacing deviation is detected, and the drilling rig is controlled to stop and an alarm is triggered.

[0039] Example 4: The difference between this embodiment and Embodiment 3 is that when the turntable 76 moves at a constant speed to create the interval marking strips, if the rotation speed of the turntable 76 is lower than the travel speed of the drill rod 41, when the marking strip 71 contacts the surface of the drill rod 41, the drill rod 41 continues to move forward, and the marking strip 71 experiences sliding friction relative to the surface of the drill rod 41. The originally thin marking strip formed by instantaneous contact will be stretched into a thicker line. In this case, the marking strip image captured by the camera 72 will be too thick, causing the data processing module to be unable to accurately identify the start and end positions of adjacent marking strips. This leads to the erroneous inclusion of the width of the thicker line in the spacing calculation, making the actual detected spacing value smaller than the theoretical spacing deviation (for example, a marking strip with a theoretical spacing of 10cm is stretched to 4cm due to sliding; during detection, the spacing between adjacent marking strips 71 is easily misjudged as 12cm-4cm=8cm, with the deviation still within the ±5% threshold). This masks the true error of the drive roller 73 slipping, preventing the triggering of alarms and data correction, resulting in measurement inaccuracies. Therefore, this embodiment improves the drive unit.

[0040] Please see Figure 7 and Figure 8The drive unit includes a crank 77 and a connecting rod 78. One end of the crank 77 is welded and fixed to the shaft of the drive roller 73, and the other end of the crank 77 is hinged to the connecting rod 78. The free end of the connecting rod 78 is hinged to the slider 79 through a spherical bearing. A connecting rod 716 is provided on the frame 75. The connecting rod 716 has an "L" shaped structure. One end is welded and fixed to the frame 75, and the other end is connected to a sleeve 717. The sleeve 717 is horizontally set and located above the drill rod 41. The slider 79 is slidably disposed in the sleeve 717, and the center line of the slider 79 is eccentrically set with respect to the rotation center of the drive roller 73. The eccentricity e between the center line of the slider 79's sliding trajectory and the center of the shaft of the drive roller 73 is 4cm. The slider 79 is closer to the surface of the drill rod 41, thus forming an offset crank-slider structure, which makes the slider 79 produce a quick return characteristic during reciprocating motion. It should be noted that those skilled in the art can adjust the lengths of the crank 77 and connecting rod 78 as needed, so that the slider 79 has a "quick return characteristic" during horizontal reciprocating motion. A lever 710 is connected to one end of the slider 79 near the drive roller 73. A carrier plate 711 is connected to the marking strip 71. A vertically arranged support rod 712 is connected to the carrier plate 711. A bracket (not shown) is slidably connected to the support rod 712. The bracket is fixedly mounted on the frame 75. A spring 713 for resetting is passed through the support rod 712. The spring 713 is a cylindrical helical spring. One end of the spring 713 is fixedly connected to the outer wall of the support rod 712, and the free end is fixedly connected to the bracket. An air bladder 721 is provided on the carrier plate 711. The air bladder 721 is made of nitrile rubber and can return to its initial state after being compressed. It is filled with red quick-drying ink, but the ink does not completely fill the space inside the ink bladder 721. The air bladder 721 has a discharge port (not shown) with a one-way valve, allowing ink to be discharged in one direction to prevent backflow. One end of the discharge port is connected to the inner cavity of the air bladder 721, and the other end is connected to the marking strip 71. When the marking strip 71 contacts the drill rod 41, the air bladder 721 is compressed, and the ink is delivered to the marking strip 71 through the discharge port, thereby replenishing the ink in the marking strip 71. At the same time, to further improve the ink compensation, in this embodiment, the side of the air bladder 721 away from the carrier plate 711 is set into an arc-shaped structure, and the cross-section is higher than the thickness of the marking strip 71. This allows the marking strip 71 to first squeeze the ink in the air bladder 721 into the marking strip 71 after each collision with the drill rod 41, and then mark the drill rod 41 with the marking strip 71. The free end of the lever 710 is provided with a pressure ball 714, and the free end of the support rod 712 is provided with a pressure ball 715. The surfaces of both are smooth, reducing friction and wear during contact. The pressure ball 714 and the pressure ball 715 are arranged opposite to each other, which makes it easy for the lever 710 to push the support rod 712 to move. The distance that the pressure ball 714 pushes the pressure ball 715 to move downward is greater than the distance between the marking strip 71 and the drill rod 41, so that the marking strip 71 and the surface of the drill rod 41 make contact with the marking.

[0041] During operation, when the drive roller 73 rotates, it drives the crank 77 to make a circular motion, which in turn drives the slider 79 to make a reciprocating linear motion through the connecting rod 78. Since the center line of the slider 79 is eccentrically set with the rotation center of the drive roller 73, it forms an offset crank-slider structure, which causes the slider 79 to have a quick return characteristic during the reciprocating motion, that is, the speed of the forward and backward motion is different, and the speed of the slider 79 is lower than the speed of the return motion. When slider 79 returns, it drives lever 710 to move synchronously, causing pressure ball 714 and pressure ball 715 to abut against each other. This moves marker strip 71 towards drill rod 41, and airbag 721 contacts the surface of drill rod 41 first, squeezing a small amount of ink from airbag 721 onto marker strip 71. When slider 79 returns to its return limit position, pressure ball 714 pushes pressure ball 715 to its limit position, causing marker strip 71 to contact the surface of drill rod 41 and squeezing ink onto drill rod 41, leaving a marker strip on the surface of drill rod 41. When crank 77 continues to rotate, and slider 79 leaves its return limit position, spring 713 drives support rod 712 to return to its initial position, and marker strip 71 moves away from the surface of drill rod 41, pausing the marking action. Since slider 79 completes one reciprocating motion and triggers one marking action for each circular motion of crank 77, marker strips are applied to drill rod 41 at axial intervals. Furthermore, during this process, if the drive roller 73 rotates normally, the spacing between the marker strips will be the theoretical design value; if the drive roller 73 rotates abnormally, the reciprocating frequency of the slider 79 will be abnormal, causing the actual spacing between the marker strips to deviate from the theoretical value, thus triggering detection (e.g., Figure 7 (As shown).

[0042] Please continue reading. Figure 8 A nozzle 718 is provided on the side wall of the sleeve 717 near the drill rod 41. The nozzle 718 communicates with the inner cavity of the sleeve 717. The outlet end of the nozzle 718 faces the drill rod 41, and its centerline is inclined at 30° towards the direction of travel of the drill rod 41, so that the airflow from the nozzle 718 forms an angle with the surface of the drill rod 41. The area to be marked is cleaned before the marking strip 71 contacts the drill rod 41. A rubber plug 720 is provided at the end of the slider 79 facing the nozzle 718. The rubber plug 720 is made of fluororubber and has an interference fit of 0.5mm with the inner wall of the sleeve 717 to prevent gas leakage from the gap. The sleeve 717 has a through groove 719 for the connecting rod 78 to swing. The length of the through groove 719 meets the movement stroke requirements of the connecting rod 78. When the slider 79 moves toward the nozzle 718, the rubber plug 720 compresses the gas inside the sleeve 717, and the gas is ejected through the nozzle 718 to blow away the coal dust and rock powder on the surface of the drill rod 41, which reduces the slippage of the drive roller 73 and makes the markings on the marking strip 71 clear.

[0043] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A mine underground return air shaft, comprising a shaft (1), wherein a connecting passage (11) is provided at the bottom of the shaft (1), characterized in that: The well casing (1) is provided with prefabricated well rings (2) arranged in sequence along the axial direction, and the space between the prefabricated well rings (2) and the original rock of the well casing (1) is filled with a backfill layer (3) formed by slurry.

2. A method for constructing an underground return air shaft in a mine, characterized in that, Includes the following steps: Step S10: Construct two connecting passages (11) in the upper and lower middle sections of the return air shaft area in the mine, and pour the floor in the area where the upper connecting passage (11) air shaft is located; Step S20: Use a reverse drilling rig (4) to carry out a reverse drilling operation on the ground. During the operation, measure the drilling depth of the drill rod (41) according to the construction depth to form the prototype of the well barrel (1). After the reverse drilling is completed, pour yellow sand (5) into the well barrel until the well barrel (1) is filled. Step S30: Use concrete to cast precast well ring (2), the diameter of which is determined according to the size of well cylinder (1); and transport the qualified precast well ring (2) to the construction site of the underground return air shaft for later use; Step S40: Transport the prefabricated well ring to the construction site of the return air shaft for later use; install a winch (6) and pulley (61) above the wellhead in the upper and middle section; connect the pulley (61) through the wire rope (62) of the winch (6), and then lower the prefabricated well ring (2) along the center of the shaft (1). After hoisting the first section of the prefabricated well ring (2) to the wellhead position, gradually discharge the yellow sand in the well so that the well ring sinks with the yellow sand. At the same time, continue to hoist the subsequent prefabricated well rings (2) at the wellhead and stack them in sequence. Repeat this process until the prefabricated well rings (2) are stacked to the height of the preset shaft (1). Step S50: Fill the gap between the outer wall of the precast well ring (2) and the original rock of the well barrel (1) with concrete slurry; Step S60: After the concrete slurry has solidified and the shaft (1) has stabilized, the return air shaft construction is completed.

3. The method for constructing an underground return air shaft in a mine according to claim 2, characterized in that: In step S20, a measuring device (7) is used to measure the drilling depth of the drill rod (41); the measuring device (7) includes: The clamping unit includes a drive roller (73), a clamping roller (74), and a frame (75). The drive roller (73) and the clamping roller (74) are both mounted on the frame (75). There are two clamping rollers (74), which are arranged in a triangular pattern with the drive roller (73) to clamp the drill rod (41). A rotary encoder (8) is fixedly connected coaxially to the shaft of the drive roller (73). A marking strip (71) is used to mark the surface of the drill pipe (41); The driving unit is used to drive the marking strip (71) to mark the marking strip at intervals along the drill rod (41); Camera (72), the camera (72) is used to capture images of the signage strip and transmit the image information to the data processing module; The data processing module is used to receive image information and identify the spacing between adjacent marker bars in the detection image.

4. The method for constructing an underground return air shaft in a mine according to claim 3, characterized in that: The drive unit includes a turntable (76), which is coaxially and fixedly connected to the drive roller (73), and the marking strip (71) is provided on the outer periphery of the turntable (76).

5. The method for constructing an underground return air shaft in a mine according to claim 3, characterized in that: The drive unit includes a crank (77) and a connecting rod (78). One end of the crank (77) is coaxially fixedly connected to the drive roller (73). The free end of the crank (77) is hinged to the connecting rod (78). A slider (79) is hinged to the free end of the connecting rod (78). The slider (79) is horizontally slidably connected to the frame (75). The center of the slider (79) is eccentrically set with respect to the rotation center of the drive roller (73). A lever is connected to the end of the slider (79) near the drive roller (73). The rod (710) is connected to the carrier plate (711), the carrier plate (711) is connected to the support rod (712), the support rod (712) is provided with a spring (713) for resetting the support rod (712), the support rod (712) is slidably connected to the bracket, the bracket is fixed on the frame (75), and the free end of the lever (710) is used to abut against the free end of the support rod (712) so that the marking strip (71) contacts the surface of the drill rod (41).

6. The method for constructing an underground return air shaft in a mine according to claim 5, characterized in that: The free end of the lever (710) is provided with a pressure ball (714), and the free end of the support rod (712) is provided with a pressure ball (715). The pressure ball (714) and the pressure ball (715) are arranged opposite to each other and are used to abut against each other.

7. The method for constructing an underground return air shaft in a mine according to claim 5, characterized in that: The carrier plate (711) is provided with an airbag (721), the airbag (721) contains ink, the airbag (721) has a discharge port, one end of the discharge port is connected to the inner cavity of the airbag (721), and the other end is connected to the marking strip (71).

8. A method for constructing an underground return air shaft in a mine according to claim 5, characterized in that: The frame (75) is provided with a connecting rod (716), and the connecting rod (716) is provided with a horizontally arranged sleeve (717). The side wall of the sleeve (717) is provided with a spray hole (718), and the spray hole (718) is connected to the inner cavity of the sleeve (717). The air outlet end of the spray hole (718) faces the drill rod (41). The slider (79) is slidably disposed in the sleeve (717) and performs reciprocating linear motion along the axial direction of the sleeve (717). The sleeve (717) is provided with a through groove (719) for the connecting rod (78) to move.

9. A method for constructing an underground return air shaft in a mine according to claim 8, characterized in that: The centerline of the nozzle (718) is inclined toward the direction of travel of the drill rod (41), so that the airflow ejected from the nozzle (718) forms an angle with the surface of the drill rod (41).

10. A method for constructing an underground return air shaft in a mine according to claim 8, characterized in that: The slider (79) is provided with a rubber plug (720) at one end facing the nozzle (718), and the rubber plug (720) is interference-fitted with the inner wall of the sleeve (717).

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