Controllable intelligent segmented grouting anchor rod based on sound wave detection and construction method

Abstract

The invention discloses a controllable intelligent segmented grouting anchor rod based on sound wave detection and a construction method. The anchor rod adopts a nested physical structure, and the sound wave detection mechanism and the grouting positioning mechanism are integrated in different layer spaces of the anchor rod, so that the supporting component has a real-time surrounding rock inspection function. The control unit identifies fracture distribution according to sound wave feedback data, formulates an intelligent grouting sequence from deep to shallow and from micro to macro, drives the grouting inner rod to accurately align, cooperates with the communicating piece to directionally guide flow, forcibly injects grout into micro fractures in a specific layer, and constructs a uniform and compact integral bearing ring. The filling quality is judged in real time by comparing sound wave characteristics before and after grouting, automatic switching is executed, and closed-loop operation of sensing recognition, accurate grouting and dynamic monitoring is achieved. The problems of detection and injection disjunction, uneven slurry distribution and the like are effectively solved, and the overall strength and long-term safety of surrounding rock of the underground chamber are remarkably enhanced.

Description

[Technical Field] This invention relates to the field of underground engineering support and surrounding rock reinforcement technology, and in particular to a controllable intelligent segmented grouting anchor bolt based on acoustic wave detection and its construction method. [Background Technology] In the construction and operation of large underground chambers, the stability control of the deep surrounding rock is always the core factor restricting the safety of the project. Due to the characteristics of the deep geological environment, such as high ground stress, high osmotic pressure, and complex alternating loads, the surrounding rock often has a large number of hidden macroscopic fracture zones and microscopic stress fissures. The anisotropic distribution of these internal defects leads to a significant decrease in the integrity and bearing capacity of the surrounding rock, which can easily cause disasters such as large deformation, collapse, and even rockburst in the chamber.

[0001] Currently, grouting and anchor bolt support is the most commonly used technique for reinforcing fractured surrounding rock and improving its mechanical properties. However, existing support and reinforcement technologies still face the following significant technical bottlenecks in practical engineering applications: First, there is a severe disconnect between sensing methods and reinforcement procedures. Traditional surrounding rock detection typically relies on borehole inspection or geophysical exploration, which are mostly post-inspection or discrete sampling methods. These methods are difficult to provide real-time, continuous feedback on the internal physical state of the surrounding rock during grouting. This "separation of detection and grouting" work mode prevents construction personnel from adjusting reinforcement strategies in real time according to the dynamic evolution of the surrounding rock structure.

[0002] Secondly, the "blind injection" phenomenon and uneven grout distribution during the grouting process are problematic. Current technologies generally rely solely on the operator's experience, leading to a degree of blindness and arbitrariness. Due to a lack of effective methods for accurate layer alignment and flow field control, grout often preferentially migrates along macroscopic fractures with lower resistance under pressure, while microscopic stress fractures that truly threaten structural safety often suffer from extremely low grout permeability due to poor venting or insufficient pressure. This lack of spatial resolution results in highly uneven reinforcement quality within the surrounding rock, making it difficult to form a unified load-bearing ring. [Summary of the Invention] The purpose of this invention is to provide a controllable intelligent segmented grouting anchor bolt and construction method based on acoustic wave detection, which aims to solve the problems in existing underground chamber support technology, such as uncontrollable reinforcement quality, serious blind grouting, uneven distribution of grout between macro and micro cracks, and difficulty in forming a balanced bearing ring.

[0003] This invention is achieved through the following technical solutions: A controllable intelligent segmented grouting anchor bolt based on acoustic wave detection, comprising: An anchor bolt assembly includes an anchoring end disposed at the depth of the borehole, the anchoring end being connected to an anchor bolt housing, the anchor bolt housing having a plurality of first grout drainage holes along its length, a hollow anchor bolt body being fitted inside the anchor bolt housing, the anchor bolt body having a plurality of second grout drainage holes along its length corresponding to the first grout drainage holes, a connecting member being provided between each first grout drainage hole and its corresponding second grout drainage hole, and a pad and a locking nut being fitted at the tail end of the anchor bolt body; A sealing and isolation assembly is disposed at the tail end of the anchor bolt body and near the pad, including a sealing ring for sealing the gap between the anchor bolt housing and the borehole to form a pressurized sealed space during grouting; The acoustic wave detection mechanism is located inside the anchor bolt housing and can reciprocate along the axial direction to dynamically scan and acquire acoustic wave feedback data of the surrounding rock. The grouting positioning mechanism includes a grouting inner rod that passes through the anchor body and can be axially displaced. One end of the grouting inner rod is provided with a grout outlet, and the other end of the grouting inner rod is connected to a drive mechanism for driving it to generate axial displacement. The grouting inner rod can be aligned with the second row of grout holes of the anchor body under the drive of the drive mechanism. The control unit is connected to the acoustic wave detection mechanism and the grouting positioning mechanism respectively; The control unit identifies the crack segments based on the acoustic feedback data, instructs the grouting inner rod to be positioned at the corresponding second grouting hole, and performs segmented grouting and automatic switching using the sealed environment constructed by the sealing and isolation components.

[0004] As described above, the controllable intelligent segmented grouting anchor bolt based on acoustic wave detection has multiple axially extending slide rails on the inner wall of the anchor bolt housing. The acoustic wave detection mechanism includes a slider mechanism installed on the slide rails, and an acoustic wave detection device and a power supply device are installed on the slider mechanism.

[0005] As described above, the controllable intelligent segmented grouting anchor bolt based on acoustic wave detection includes a slider mechanism comprising a slider base, a slider motor mounted on the slider base, the slider motor being electrically connected to the power supply device, an output shaft of the slider motor being connected to a drive bevel gear, the drive bevel gear being driven by a transmission bevel gear, the transmission bevel gear being connected to a first roller perpendicular to the slider base, the transmission end of the first roller being fixedly connected to the transmission bevel gear and its rolling end being rolledly connected to one of the slide rails, a second roller perpendicular to the slider base being provided next to the first roller, the transmission end of the second roller passing through the slider base and being connected to the transmission end of the first roller via a reverse belt drive, and the rolling end of the second roller being rolledly connected to the other slide rail.

[0006] As described above, in the controllable intelligent segmented grouting anchor bolt based on acoustic wave detection, both the first roller and the second roller have annular grooves at their transmission ends for installing the reverse belt, and the annular grooves of the two rollers are staggered.

[0007] As described above, the controllable intelligent segmented grouting anchor bolt based on acoustic wave detection includes a drive mechanism comprising two screw support seats, a screw rod between the two screw support seats, a screw rod motor connected to one end of the screw rod, the screw rod motor being signal-connected to the control unit, a movable block connected to the screw rod, and a ball nut fixedly connected to the movable block at the outer end of the grouting inner rod.

[0008] As described above, in the controllable intelligent segmented grouting anchor bolt based on acoustic detection, the connecting member is a hollow tubular structure, with its two ends welded and fixed to the first grout discharge hole and the second grout discharge hole, respectively, to guide the grout during grouting to avoid it flowing into the annular gap between the anchor bolt shell and the anchor bolt body.

[0009] A construction method comprising the following steps: S1. Drilling and preliminary anchoring: Drilling is carried out according to the designed diameter and depth. After removing the broken rock in the hole, a controllable intelligent segmented grouting anchor rod based on acoustic detection, as described above, is installed into the borehole. The anchoring end is used for preliminary anchoring, and the pad and the sealing ring are tightened to seal the hole opening. S2. Full-hole pre-scan detection: The control unit issues a command to drive the slider motor to move the acoustic detection device along the slide rail from the anchor end to the borehole opening at a constant speed, and collects acoustic data on the development and distribution of fractures in the surrounding rock of the entire borehole section; S3. Fracture Identification and Intelligent Segmentation: The control unit processes the collected acoustic data, identifies the distribution locations of macroscopic and microscopic fractures by analyzing acoustic characteristics, and divides the borehole surrounding rock into several grouting segments according to the fracture distribution. S4. Formulate intelligent grouting sequence: The control unit sets the grouting priority of the micro-fracture segments located in the deep part of the borehole to be higher than that of the macro-fracture segments located in the shallow part of the borehole according to the fracture type and depth position of each segment identified in step S, and generates a grouting sequence that switches sequentially from the anchor end to the borehole opening. S5. Point alignment and grouting: The control unit instructs the drive mechanism to drive the grouting inner rod to perform axial displacement, so that the grout outlet of the grouting inner rod is precisely aligned with the second row of grout holes at the target layer corresponding to the current crack segment to be grouted, and the grouting pump is started to perform point grouting; S6. Dynamic monitoring and judgment: During the grouting process, the acoustic wave detection mechanism moves back and forth within the slide rail interval corresponding to the current grouting segment to implement dynamic monitoring; the control unit determines whether the surrounding rock fissures in the grouting segment have been fully filled and consolidated by comparing the acoustic wave propagation characteristics before and after grouting. S7. Closed-loop automatic switching: If the current fracture segment is determined to be filled to the standard, the control unit automatically drives the grouting positioning mechanism to move to the target layer corresponding to the next fracture segment; if it is not filled to the standard, grouting continues until acoustic monitoring confirms that the segment is filled to the standard.

[0010] In the construction method described above, in step S6, the filling is deemed satisfactory by comparing the current acoustic wave detection results with the original acoustic wave data before grouting. The judgment criteria include: the amplitude of the crack reflection wave after grouting is attenuated compared with that before grouting and reaches a preset threshold; the rate of change of the acoustic wave propagation speed within a preset sampling period enters a stable range; and the characteristic parameters of the echo signal conform to the preset acoustic characteristics of dense medium.

[0011] As described above, after each grouting segment is determined to be filled to the standard, the control unit instructs the external grouting system to maintain the grouting pressure for 3 to 5 minutes to ensure that the grout sprayed by the grouting rod is fully solidified in the surrounding rock fissure zone and to prevent grout backflow. Then, the switching in step S7 is executed.

[0012] As described above, when the control unit determines that the last crack segment in the grouting sequence has been filled to the standard and the pressure has been maintained, the pad is removed, the acoustic detection mechanism is axially pulled out from inside the anchor bolt housing, and then a pre-tightening force is applied to the anchor bolt body to complete the support operation.

[0013] Compared with the prior art, the present invention has the following advantages: 1. This invention integrates the acoustic detection mechanism and the grouting positioning mechanism into different layers of the anchor bolt shell and the anchor bolt body, respectively. This allows the anchor bolt to not only possess the load-bearing function of traditional support components but also serve as an inspection device for the surrounding rock. This integrated design avoids the delays and cost surges caused by secondary drilling and inspection, and enables real-time and continuous sensing of the development of fractures within the surrounding rock.

[0014] 2. This invention utilizes the precise axial displacement of the grouting inner rod within the anchor body, combined with the directional flow guidance of the connecting component, to forcefully inject grout into specific fracture-developed strata. This controlled flow field distribution pattern ensures that high-pressure grout accurately penetrates deep micro-fractures that threaten structural safety, preventing ineffective grout migration along macro-fractures, thereby constructing a uniformly thick and densely cemented integral bearing ring within the surrounding rock.

[0015] 3. This invention optimizes the grout penetration path in heterogeneous rock masses by pre-setting an intelligent grouting sequence that proceeds from deep to shallow and from micro to macro, ensuring the systematic nature of surrounding rock reinforcement. The system prioritizes processing micro-fracture segments located deep within the borehole, effectively preventing the compaction effect caused by premature filling of shallow macro-fractures from closing deep channels. This dynamic decision-making logic based on geological feedback aligns with the stress evolution of the surrounding rock and the hemodynamic characteristics of the grout, resulting in a more thorough improvement in the mechanical properties of the surrounding rock and significantly enhancing the long-term stability of underground chambers under complex stress environments. [Attached Image Description] To more clearly illustrate the technical solutions in the embodiments of the invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0016] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1; Figure 2 This is a schematic diagram of the planar structure of the anchoring end in Embodiment 1; Figure 3 for Figure 2 A sectional view along line AA. Figure 4 This is a schematic diagram of the planar structure of the anchor bolt body in Example 1; Figure 5 for Figure 4 Sectional view along line BB; Figure 6 This is a schematic diagram of the planar structure of the grouting inner rod in Example 1; Figure 7 for Figure 6 A cross-sectional view along the CC line; Figure 8 This is a schematic diagram of the planar structure of the anchor bolt shell in Embodiment 1; Figure 9 for Figure 8 A sectional view along the DD line; Figure 10 This is a three-dimensional schematic diagram of the acoustic wave detection mechanism in Example 1; Figure 11 This is a three-dimensional schematic diagram of the first roller in Embodiment 1.

Detailed Implementation Methods

[0017] Example 1: In current support and reinforcement projects for large underground chambers, the stability control of the surrounding rock remains a core challenge. Due to the extremely complex geological environment at depth, the surrounding rock often contains a large number of microscopic fissures invisible to the naked eye and macroscopic fracture zones, which directly threaten the safety of the chamber.

[0018] Currently, grouting anchors are widely used for reinforcement in the industry, but traditional technical solutions have significant limitations. On the one hand, traditional grouting processes are often indiscriminate, as construction personnel cannot obtain real-time information on the actual penetration status of the grout within the surrounding rock, making it difficult to accurately identify which sections require reinforcement. This results in grout accumulating at macroscopic fissures while failing to penetrate sufficiently at microscopic fissures. On the other hand, existing testing methods are usually disconnected from the grouting process, often requiring separate drilling for testing after grouting is completed. This not only significantly increases construction costs and time but also fails to achieve a closed-loop linkage between testing and reinforcement.

[0019] In response to the aforementioned engineering difficulties, such as Figures 1 to 11 As shown, this embodiment discloses a controllable intelligent segmented grouting anchor bolt based on acoustic wave detection, including an anchor bolt assembly 1 as the core load-bearing frame, with an anchoring end 11 extending deep into the borehole at its front end. The anchoring end 11 is fixedly connected to the anchor bolt housing 12, which has multiple first grout drainage holes 121 along its length. Inside the anchor bolt housing 12, a hollow anchor bolt body 13 is coaxially fitted, with multiple second grout drainage holes 131 corresponding to its pipe wall position. This nested design forms an independent annular physical space between the anchor bolt housing 12 and the anchor bolt body 13.

[0020] Considering the limitations of working space and height in underground chambers, both the anchor bolt shell 12 and the anchor bolt body 13 in this embodiment adopt a modular segmented design, consisting of multiple standard-length unit segments connected sequentially. Specifically, adjacent anchor bolt shell 12 unit segments are coaxially connected via high-strength threaded sleeves or positioning joints; correspondingly, each unit segment of the anchor bolt body 13 is also rigidly sealed via built-in or external threaded joints. This segmented structure allows construction personnel to assemble and push the anchor bolts section by section at the borehole opening according to the drilling depth, effectively avoiding the problem of long anchor bolts being difficult to transport and install in a chamber environment.

[0021] To ensure that the high-pressure grout does not interfere with the detection space during its flow, a connecting element (not shown in the figure) is sealed between each first grout discharge hole 121 and its corresponding second grout discharge hole 131. This connecting element spans the aforementioned annular physical space, creating a completely isolated grouting flow path. The tail end of the anchor bolt body 13 extends to the surface of the chamber and is fitted with a pad 15 and a locking nut 16. By tightening the locking nut 16, the pad 15 is pressed tightly against the surrounding rock surface, thereby achieving effective transmission of support force.

[0022] Based on this, this embodiment also includes a sealing and isolation component 2 to provide a reliable pressure boundary for the grouting operation. Please refer to [link / reference needed]. Figure 1 The sealing and isolating component 2 is located at the tail end of the anchor bolt body 13 and adjacent to the pad 15. This component includes a sealing ring 21 fitted around the outer periphery of the anchor bolt housing 12, whose main function is to seal the construction gap between the anchor bolt housing 12 and the borehole inner wall. During grouting operations, the sealing ring 21 can prevent the grout from flowing out towards the borehole opening, thereby forming a pressurized, sealed space deep within the borehole, forcing the grout to penetrate deep into the surrounding rock fissures.

[0023] To achieve real-time detection of defects within the surrounding rock of the tunnel, an acoustic detection mechanism 3 is installed in the annular space inside the anchor bolt housing 12. This acoustic detection mechanism 3 can reciprocate along the axial direction, continuously acquiring acoustic feedback data of the surrounding rock through dynamic scanning, providing a basis for subsequent intelligent judgment. Simultaneously, a grouting positioning mechanism 4 is also installed to perform the final precise reinforcement task. For details, please refer to [link to details]. Figure 6 , Figure 7 The grouting positioning mechanism 4 includes an inner grouting rod 41 that passes through the anchor body 13 and is axially movable. Corresponding to the structure of the anchor body 13, the inner grouting rod 41 is also composed of multiple rod unit segments connected sequentially by high-precision threads or pin joints to ensure sufficient push-pull stiffness during long-distance axial movement. The front end of the inner grouting rod 41 is provided with a grout outlet 411, and the rear end is connected to a drive mechanism 42 that drives it to generate linear displacement.

[0024] Furthermore, the controllable intelligent segmented grouting anchor bolt based on acoustic wave detection proposed in this embodiment has its overall operation logic uniformly commanded and coordinated by a control unit (not shown in the figure) that serves as the core logic hub. This control unit establishes bidirectional signal connections with the acoustic wave detection mechanism 3 and the grouting positioning mechanism 4 through data transmission links, ensuring the real-time nature of command issuance and data feedback.

[0025] Specifically, during the detection phase, the acoustic detection mechanism 3 performs a cruise scan along the anchor bolt axis, collecting the raw acoustic waveforms inside the surrounding rock and transmitting them to the control unit. The processing module inside the control unit accurately identifies the specific spatial coordinates of macroscopic and microscopic fractures in the surrounding rock by comparing the propagation speed, amplitude attenuation, and frequency response characteristics of the acoustic waves in different media, and divides them into different grouting logic segments. After identifying the layer to be reinforced, the control unit converts the physical coordinates of that layer into axial pulse commands and issues them to the drive mechanism 42.

[0026] Upon receiving the command, the drive mechanism 42 drives the grouting inner rod 41 to precisely translate within the hollow anchor body 13 until the grout outlet 411 at the front end of the grouting inner rod 41 is axially aligned with the second row of grout holes 131 at the preset target layer, thereby constructing a directional flow channel from the grouting pump to the surrounding rock fissures. During this process, since the sealing and isolation component 2 has pre-formed a stable mechanical seal between the anchor housing 12 and the borehole inner wall, the grout input by the grouting pump can forcefully penetrate into the deep part of the surrounding rock within the pressurized sealed space through the grout outlet 411, the second row of grout holes 131, and the corresponding connecting parts.

[0027] It should be noted that during grouting operations, the control unit does not only perform a single injection action, but also synchronously monitors the quality of the current grouting area through the acoustic detection mechanism 3. The control unit continuously monitors the dynamic changes in acoustic feedback data, and once the acoustic parameters of the current layer reach the preset dense medium characteristic threshold, the grouting of that segment is deemed satisfactory. Subsequently, the control unit automatically issues a sequence switching command, driving the grouting positioning mechanism 4 to move to the next target layer in the sequence, thus realizing a complete closed-loop process for the entire borehole section from detection and identification to fixed-point grouting, and then to quality judgment and automatic switching. This highly integrated control logic not only greatly improves the operational accuracy of the chamber reinforcement, but also ensures the optimal allocation of grout resources.

[0028] Furthermore, as an optional implementation, the control unit can be physically mounted as an industrial-grade integrated control box on the tail of the anchor bolt body 13 or on a support on the surface of the chamber. This control box can use an alloy sealed housing with waterproof, dustproof, and impact-resistant properties, and integrates a core processing module, drive control circuit, data acquisition board, and power management module. The external panel of the control box has a human-machine interface for real-time display of surrounding rock acoustic waveform data, grouting pressure curve, and the axial position coordinates of the current grouting inner rod 41.

[0029] Regarding the specific connection path, the control unit and the acoustic wave detection mechanism 3 can be connected via a flexible shielded cable arranged in the annular space inside the anchor housing 12. To accommodate the reciprocating linear motion of the acoustic wave detection mechanism 3, the flexible shielded cable can be wired using a tank chain or telescopic spiral cable method. One end connects to the data interface of the control box, and the other end moves with the slider mechanism and connects to the signal input terminal of the acoustic wave detection device 32. This wiring design effectively prevents the cable from tangling or fatigue breaking during high-speed reciprocating motion, while the shielding layer significantly reduces the interference of electromagnetic noise generated by the grouting pump station on weak acoustic wave signals.

[0030] Meanwhile, the connection between the control unit and the grouting positioning mechanism 4 can be more direct. Since the drive mechanism 42 is fixedly located at the tail end of the anchor bolt body 13, the control unit can be connected to the power motor driver in the drive mechanism 42 via a short-distance industrial bus (such as a CAN bus or RS485 bus). The digital pulse commands sent by the control unit are amplified by the driver and directly converted into precise stepping movements of the drive mechanism 42. Furthermore, a high-precision displacement sensor can be installed on the drive path of the grouting inner rod 41. This sensor feeds back the real-time position signal of the grouting inner rod 41 to the control unit, thus forming a closed-loop position control system. This connection architecture ensures that even under complex construction conditions inside the tunnel, the control unit can still accurately control the real-time dynamics of the detection mechanism and the displacement accuracy of the grouting mechanism, thereby providing a communication foundation for intelligent operation throughout the entire borehole section.

[0031] Furthermore, as a preferred embodiment and not a limitation, to ensure the stability and detection accuracy of the acoustic detection mechanism 3 during axial movement, the inner wall of the anchor bolt housing 12 is provided with multiple axially extending slide rails 122. Please refer to [link to relevant documentation]. Figures 8 to 9 These slide rails 122 are arranged on the inner circumferential surface of the anchor bolt housing 12. The number of slide rails can be two, three, four, etc., designed to provide multi-point support and restraint for the internal moving components, preventing rotation or eccentric swaying during reciprocating motion. The slide rails 122 can be made of corrosion-resistant hard alloy steel or stainless steel and are fixed to the inner wall of the anchor bolt housing 12 by precision welding and embedded slots. Their surfaces are finely ground or coated to reduce frictional resistance and improve wear resistance. Specifically, since the anchor bolt housing 12, as described above, is composed of multiple unit segments, the ends of the slide rails 122 are provided with alignment structures or guide chamfers at the joints between the unit segments of the anchor bolt housing 12, ensuring that the slider mechanism 31 can smoothly transition between unit segments without mechanical jamming or jumping. The surface of the slide rails 122 is finely ground to reduce frictional resistance.

[0032] Accordingly, the acoustic wave detection mechanism 3 specifically includes a slider mechanism 31 mounted on the slide rail 122. Please refer to [link / reference needed]. Figure 10 The slider mechanism 31 is equipped with an acoustic wave detection device 32 and a power supply device (not shown in the figure). The acoustic wave detection device 32 can be composed of a high-sensitivity ultrasonic transducer and a matching signal conditioning circuit. Its transmitting end is close to the inner wall of the anchor bolt shell 12 or coupled to the shell through a coupling medium. By emitting acoustic wave pulses that penetrate the anchor bolt wall and enter the surrounding rock, and then receiving the echo signals reflected back through the fracture interface, the physical state of the surrounding rock inside the chamber can be dynamically scanned.

[0033] To enable the acoustic detection mechanism 3 to autonomously navigate deep within the underground chamber and eliminate the constraints of lengthy cables, a power supply unit is integrated into the slider mechanism 31. This power supply unit can utilize a high-energy-density lithium battery pack to provide stable power to the slider motor, acoustic detection device 32, and wireless communication module. By directly mounting the power supply unit onto the slider mechanism 31, not only is the wiring structure inside the anchor bolt simplified, reducing the risk of short circuits caused by frequent cable expansion, contraction, and wear, but the operational flexibility of the detection mechanism in complex support environments is also greatly enhanced.

[0034] As an alternative to achieve the function or structure, the slide rail 122 can also adopt a dovetail groove structure or a T-groove structure integrally formed with the anchor rod housing 12, and ensure the smooth operation of the slider mechanism 31 through mechanical interlocking. At the same time, in addition to using the vehicle battery mode, the power supply device can also consider using electromagnetic induction wireless power supply technology or sliding contact line power supply method, using the conductive track laid on the slide rail 122 to replenish the power of the moving slider mechanism 31 in real time.

[0035] Furthermore, as a preferred embodiment and not a limitation, the slider mechanism 31 includes a slider base 311, which serves as the mounting reference for the entire traveling unit. A slider motor 312 is mounted on the slider base 311, and is electrically connected to a power supply to provide power for the axial cruising of the acoustic detection mechanism. Considering the physical characteristics of the anchor bolt inner shell—ample axial space but limited radial space—the output shaft of the slider motor 312 is connected to a drive bevel gear 313, which meshes with a transmission bevel gear 314. This bevel gear pair effectively achieves a 90-degree change in the power transmission direction, guiding the rotational power of the motor shaft to a direction perpendicular to the slider base 311, thus solving the problem of arranging large-diameter drive wheels in a narrow gap. The transmission bevel gear 314 is connected to a first roller 315 perpendicular to the slider base 311. Specifically, the transmission end of the first roller 315 is fixedly connected to the transmission bevel gear 314 via a key or interference fit, thereby achieving synchronous rotation, while its rolling end is in close rolling contact with one of the slide rails 122. To further enhance traction and prevent slider deflection and jamming caused by unilateral drive, a second roller 316, also perpendicular to the slider base 311, is provided next to the first roller 315. The transmission end of the second roller 316 passes through a pre-set through hole in the slider base 311 and is connected to the transmission end of the first roller 315 via a reverse belt 317. The reverse belt 317, also known as a cross drive belt, enables the first roller 315 and the second roller 316 to rotate in opposite directions during the drive process.

[0036] This dual-roller drive system, with its co-rotating and opposite-rotating wheels, along with another slide rail 122, allows the slider mechanism 31 to generate a smooth and symmetrical axial thrust during operation through the friction between the two rollers and the two parallel slide rails 122. The rolling surfaces of the first roller 315 and the second roller 316 can be coated with a high-friction anti-slip rubber layer to ensure sufficient grip even in environments with water seepage or slurry residue.

[0037] Furthermore, as a preferred embodiment and not a limitation, to address the potential mechanical interference problem that may occur during the cross-drive process of the aforementioned reverse belt 317, both the first roller 315 and the second roller 316 have annular grooves 8 at their drive ends for mounting the reverse belt 317. See also... Figure 11 Specifically, the annular groove 8 on the first roller 315 and the annular groove 8 on the second roller 316 are axially misaligned. This spatial arrangement aims to ensure that when the reverse belt 317 is wound in a cross configuration between the two rollers, the overlapping parts of the belt can physically avoid each other due to the axial positional difference of the annular grooves 8. In the high-stress or high-dust environment of underground chambers, if there is direct contact and friction at the intersection of the reverse belt 317, localized high temperatures can easily occur, causing the belt material to soften, slip, or even break, leading to power failure of the detection mechanism. By misaligning the annular grooves 8, the two spans of the reverse belt 317 run in different horizontal planes, eliminating the frictional resistance caused by the reverse belt's own interference, greatly improving power transmission efficiency and extending the maintenance-free cycle of the transmission system.

[0038] Optionally, the cross-sectional shape of the annular groove 8 can be specifically adapted to the type of belt used. For example, a V-groove can be used to adapt to high-friction V-belts, or an arc groove can be used to adapt to more flexible O-ring belts, thereby enhancing the stability of power transmission. At the same time, the axial misalignment spacing of the annular groove 8 can be set to be slightly larger than the single-sided thickness of the reverse belt 317, so as to minimize the total length of the transmission ends of the first roller 315 and the second roller 316 while ensuring reliable avoidance effect, thereby adapting to the small gap between the anchor bolt housing 12 and the anchor bolt body 13.

[0039] Furthermore, as a preferred embodiment and not a limitation, in order to achieve millimeter-level precise control of the grouting layer position under high-pressure grouting conditions in underground chambers, the drive mechanism 42 includes two symmetrically arranged screw support seats 421. These two screw support seats 421 are fixedly installed on a reference platform (not shown in the figure) at the tail end of the anchor bolt body 13 to provide stable axial support and limiting. A screw 422 is mounted between the two screw support seats 421, and one end of the screw 422 is connected to a screw motor 423. The screw motor 423 is signal-connected to the aforementioned control unit and serves as the power core of the entire grouting alignment system, capable of receiving commands from the control unit.

[0040] A movable block 424 is connected to the lead screw 422, and a ball nut 412 is provided at the outer end of the grouting inner rod 41. The ball nut 412 and the movable block 424 are fixedly connected by high-strength bolts or welding. When the lead screw motor 423 drives the lead screw 422 to rotate, the rotational motion is converted into the axial linear motion of the movable block 424 through the cyclic rolling between the ball and the lead screw channel, thereby driving the grouting inner rod 41 to reciprocate within the anchor body 13.

[0041] As an alternative, the drive mechanism 42 can also be a hydraulic cylinder with a displacement sensor, or a gear and rack transmission mechanism. However, in electronic control systems where space is limited and cleanliness is required, the combination of the lead screw motor 423 and the lead screw 422 offers better control linearity and structural compactness. More specifically, the lead screw motor 423 can preferably be a stepper motor with a self-locking function or a servo motor with an encoder, so that during the high-pressure operation of the external grouting pump (not shown in the figure), the motor's holding force or mechanical self-locking characteristics maintain the absolute fixation of the position of the grouting inner rod 41, preventing grout leakage caused by displacement deviation.

[0042] Furthermore, as a preferred embodiment and not a limitation, to ensure that the grout completely avoids the annular gap containing precision electronic components during its diffusion from the center of the anchor bolt to the surrounding rock of the underground chamber, the connecting member is designed as a high-pressure resistant hollow tubular structure. Both ends of this connecting member are welded and fixed to the first row of grout holes 121 on the anchor bolt housing 12 and the second row of grout holes 131 on the anchor bolt body 13, respectively. This rigid, sealed connection formed by welding not only ensures the physical continuity of the grouting channel but also significantly enhances the radial support strength between the anchor bolt housing 12 and the anchor bolt body 13. This allows it to maintain the geometry of the internal annular space even under complex stress from the surrounding rock of the chamber, ensuring that the running track of the slider mechanism 31 does not deform.

[0043] During actual grouting operations, the connecting component plays a crucial bridging and guiding role. Once the grout outlet 411 of the inner grouting rod 41 is precisely aligned, the high-pressure grout flows out and passes through the second row of grout holes 131. At this point, the connecting component can forcefully guide the grout directly into the corresponding first row of grout holes 121, ultimately penetrating into the surrounding rock fissures. This guiding path eliminates the possibility of grout overflow and entering the annular gap between the anchor bolt housing 12 and the anchor bolt body 13. This design is essential for protecting the acoustic detection device 32, power supply device, and complex slider transmission mechanism, which are permanently installed within this gap, preventing precision electronic components from jamming or short-circuiting after the grout solidifies.

[0044] More specifically, the inner diameter of the connecting piece is set to be slightly larger than or equal to the diameter of the second row of slurry holes 131 in order to minimize local fluid resistance and prevent solid particles in the slurry from accumulating and clogging at the welding bend.

[0045] Example 2: This embodiment discloses a construction method based on the intelligent segmented grouting anchor bolt described in Embodiment 1 above. This method achieves differentiated and refined reinforcement of the surrounding rock fissures in underground chambers through a deep closed loop of perception, decision-making, and execution.

[0046] First, step S1 is performed for drilling and preliminary anchoring. Construction personnel drill at the target surrounding rock using a drilling rig, based on the diameter and depth requirements of the underground chamber support design. After cleaning the borehole opening, the construction personnel install the anchor bolt using a segmented splicing method: first, the first anchor bolt housing 12 with the anchoring end 11 and the anchor bolt body 13 unit are pushed into the borehole. Then, at the borehole opening, the next unit segment is continued using a threaded sleeve, simultaneously connecting the internal grouting inner rod 41 unit, until the preset depth is reached. After removing residual rock fragments and dust from the borehole, preliminary anchoring is completed by the bonding of the anchoring end 11 with the anchoring agent at the bottom of the borehole. Then, the pad 15 is tightened, and the sealing ring 21 undergoes radial expansion to seal the gap between the anchor bolt housing 12 and the borehole inner wall, thereby sealing the borehole opening and laying the foundation for the subsequent construction of the high-pressure grouting environment.

[0047] Then, step S2 is performed to conduct a full-hole pre-scan inspection. The control unit issues a cruise command, driving the slider motor 312 to work, which in turn moves the acoustic detection device 32 along the slide rail 122 from the anchor end 11 deep in the borehole towards the borehole opening at a constant speed. During this movement, the acoustic detection device 32 continuously emits and receives acoustic pulses that penetrate the surrounding rock, collecting raw acoustic data covering the development and distribution of fractures in the surrounding rock throughout the entire borehole section.

[0048] Next, step S3 is executed for fracture identification and intelligent segmentation. The processor inside the control unit extracts and filters features from the acquired acoustic data. By analyzing the reduction in wave velocity, amplitude attenuation, and waveform distortion characteristics in the surrounding rock, the specific distribution coordinates of macroscopic and microscopic fractures are identified. Based on these spatial distributions, the control unit divides the entire borehole along its axial length into several grouting segments with different reinforcement requirements.

[0049] Then, step S4 is executed to formulate an intelligent grouting sequence. This is a key step in achieving intelligent decision-making in this method. Based on the fracture type and depth location of each segment identified in step S3, the control unit generates a grouting priority queue according to the technical principle of prioritizing deep micro-fractures. Specifically, the control unit sets the micro-fracture segments located deep within the borehole as high priority and generates an axial grouting sequence that switches sequentially from the anchoring end 11 towards the borehole opening. This grouting logic, from deep to shallow and from micro to macro, effectively avoids the problem of deep micro-channel blockage caused by grout preferentially filling shallow large fractures.

[0050] Proceeding to step S5, precise alignment and grouting are performed. The control unit commands the drive mechanism 42 to operate, driving the lead screw 422 to rotate via the lead screw motor 423, thereby causing the grouting inner rod 41 to undergo precise axial displacement. During this process, the control unit precisely aligns the grout outlet 411 at the front end of the grouting inner rod 41 with the second grout discharge hole 131 at the target layer corresponding to the current grouting fracture segment. After alignment, the control unit activates the external grouting pump to perform precise grouting. The grout is injected into the target surrounding rock area through the grouting inner rod 41, the grout outlet 411, the second grout discharge hole 131, and the connecting piece.

[0051] During the grouting process, step S6 is executed simultaneously for dynamic monitoring and judgment. Under the command of the control unit, the acoustic detection mechanism 3 performs reciprocating inspection within the slide rail 122 interval corresponding to the current grouting segment. The control unit dynamically analyzes the degree of filling of the surrounding rock fissures by the grout by comparing the acoustic propagation characteristic parameters before and after grouting in real time, and determines whether the surrounding rock fissures in the current grouting segment have been fully filled and consolidated by the grout.

[0052] Finally, step S7 is executed to achieve closed-loop automatic switching. If the current fracture segment is determined by the control unit to have met the filling standard, the control unit will automatically drive the grouting positioning mechanism 4 to generate displacement, so that the grout nozzle 411 is aligned with the next target layer in the grouting sequence. If the determination result shows that the standard is not met, the control unit will instruct the external grouting system to continue working until the acoustic monitoring data confirms that the reinforcement quality of the segment meets the preset requirements.

[0053] Furthermore, as a preferred embodiment rather than a limitation, in the construction site of the underground chamber, the operation of removing the broken rock inside the hole in step S1 can be achieved by high-pressure air blowing or water flushing to ensure the cleanliness of the contact surface between the sealing ring 21 and the hole wall, thereby improving the sealing performance. Specifically, the uniform moving speed in step S2 is set between five and ten centimeters per second to balance detection efficiency and signal sampling density. Through this series of logically rigorous automated steps, this method realizes a fundamental shift from experience-based to data-driven methods for reinforcing the surrounding rock of underground chambers.

[0054] Furthermore, as a preferred implementation rather than a limitation, in order to address the technical problem that it is difficult to quantitatively determine the quality of the surrounding rock reinforcement of underground chambers in real time, during the execution of step S6, the control unit does not perform isolated data reading, but instead retrieves the original acoustic wave data of the full-hole pre-scanning stored in step S2 in real time as a comparison benchmark, and dynamically compares the acoustic wave detection results of the current monitoring point with the original data before grouting, thereby scientifically determining whether the filling meets the standards.

[0055] This criterion first includes the attenuation of the fracture reflection wave amplitude after grouting compared to before grouting, reaching a preset threshold. Specifically, when the grout fills the surrounding rock fractures and displaces the air or water within, the acoustic impedance difference at the fracture interface decreases significantly, resulting in a substantial attenuation of the originally strong fracture reflection signal. The preset threshold can be set to 30% to 50% of the original amplitude based on the lithology of the surrounding rock in the chamber. Once the amplitude drops below this range, it is preliminarily determined that the physical fracture has been occupied by the grout.

[0056] Secondly, the judgment criteria also include the rate of change of sound wave propagation velocity entering a stable range within a preset sampling period. In actual construction, as the grout is continuously injected and solidifies, the overall density and elastic modulus of the surrounding rock will continuously increase, manifested as a continuous increase in sound wave propagation velocity. The control unit continuously monitors the wave velocity change within a preset sampling period, such as five to ten seconds. When the wave velocity change curve tends to flatten, that is, when the fluctuation range of the rate of change shrinks to a preset minimum value range, it is determined that the grout penetration in that area has reached saturation.

[0057] Finally, the judgment criteria require that the characteristic parameters of the echo signal conform to the preset acoustic characteristics of the dense medium. The control unit extracts characteristic parameters such as the spectral distribution and energy centroid by performing fast Fourier transform or wavelet analysis on the echo, and matches them with the standard characteristic model of dense rock mass pre-stored in the control unit. Only when the above three criteria of reflected wave amplitude, wave velocity stability, and medium characteristic matching degree are simultaneously satisfied will the control unit issue a logical judgment that the filling meets the standard.

[0058] Furthermore, as a preferred embodiment rather than a limitation, in order to address the potential backflow of grout towards the anchor axis due to a sudden drop in pressure during high-pressure grouting in underground chambers, as well as the issue of incomplete filling at the ends of deep micro-cracks, after each specific grouting segment is determined to have met the filling standard in step S6, the control unit does not immediately execute the layer switching action, but instead issues a pressure holding command to the external grouting system to maintain the current grouting pressure for three to five minutes.

[0059] This pressure-maintaining process is crucial for enhancing the overall strength of the surrounding rock in the underground chamber. Specifically, the control unit, in real-time linkage with the pressure control module of the external grouting system, ensures that the grout ejected from the grouting inner rod 41 remains under stable high-pressure extrusion for a preset duration. This duration, set at three to five minutes, is a reasonable setting based on the initial setting characteristics of common grouting materials in underground chambers. It aims to utilize the fluidity of the grout before initial setting to force it to further penetrate into the distal ends of micro-fractures and fully compress and solidify it within the fracture zone. By actively maintaining pressure, the displacement effect caused by formation stress can be effectively counteracted before the grout loses its fluidity, thereby preventing backflow and cavitation caused by the grout at the moment the grouting pump is shut down.

[0060] During this stage, the control unit continuously monitors the pressure fluctuations of the external grouting system. If a significant pressure drop occurs during the pressure holding period, the control unit will automatically fine-tune the pumping power of the external grouting system to compensate for the pressure loss. Only when the pressure holding time reaches the preset threshold and the pressure remains stable will the control unit determine that the reinforcement work of the current layer has been successfully completed, and then instruct the layer switching action in step S7 to be executed.

[0061] Furthermore, as a preferred implementation rather than a limitation, when the control unit determines that the last fracture segment in the preset grouting sequence has reached the filling standard and the aforementioned three to five minutes of pressure holding time has been completed, the control unit automatically stops the operation of the external grouting system, marking the official end of the intelligent grouting stage of the current borehole. At this time, the construction personnel remove the pad 15 installed at the tail of the anchor bolt body 13, thereby removing the physical shielding of the anchor bolt shell 12 and the annular space inside the anchor bolt body 13.

[0062] Subsequently, construction workers used the connecting cable between the acoustic detection mechanism 3 and the control unit, or a dedicated extraction tool, to axially pull the acoustic detection mechanism 3 out of the anchor bolt housing 12. In this way, the acoustic detection mechanism can be repeatedly used to detect the next support point in the underground chamber, significantly reducing the amortization cost of intelligent monitoring in large-scale support projects. What remains inside the surrounding rock are only the lower-cost embedded parts, namely the anchor bolt housing 12, the anchor bolt body 13, and the connecting parts.

[0063] After removing the acoustic detection mechanism 3, the construction workers reinstalled the pad 15 and tightened the locking nut. Then, using a tensioning machine or high-torque wrench, they applied preload to the anchor bolt body 13. Since the anchor bolt body 13 has formed a robust composite load-bearing structure with the surrounding rock of the chamber through the surrounding grout, applying axial preload causes tensile elastic deformation of the anchor bolt body 13. This, in turn, generates active compressive stress on the surrounding rock surface of the chamber through the pad 15, thus completing the final support operation. This active support method effectively limits the early deformation of the surrounding rock and enhances its own bearing capacity.

[0064] The above are implementation methods provided in conjunction with specific content, and it is not intended that the specific implementation of this application is limited to these descriptions. Any methods or structures that are similar to those of this application, or any technical deductions or substitutions made based on the concept of this application, should be considered within the scope of protection of this application.

Claims

1. A controllable intelligent segmented grouting anchor bolt based on acoustic wave detection, characterized in that, include: An anchor assembly (1) includes an anchoring end (11) located at the depth of the borehole. The anchoring end (11) is connected to an anchor housing (12). The anchor housing (12) has a plurality of first grouting holes (121) along its length. A hollow anchor body (13) is fitted inside the anchor housing (12). The anchor body (13) has a plurality of second grouting holes (131) along its length that correspond to the first grouting holes (121). A connecting piece is provided between each first grouting hole (121) and the corresponding second grouting hole (131). A pad (15) and a locking nut (16) are fitted at the tail end of the anchor body (13). The sealing and isolation assembly (2) is located at the tail end of the anchor body (13) and near the pad (15), and includes a sealing ring (21) for sealing the gap between the anchor housing (12) and the borehole to form a pressurized sealed space during grouting; The acoustic wave detection mechanism (3) is located inside the anchor bolt shell (12) and can move back and forth along the axial direction to dynamically scan and acquire acoustic wave feedback data of the surrounding rock; The grouting positioning mechanism (4) includes a grouting inner rod (41) that passes through the anchor body (13) and can be axially displaced. One end of the grouting inner rod (41) is provided with a grout outlet (411), and the other end of the grouting inner rod (41) is connected to a driving mechanism (42) for driving it to generate axial displacement. The grouting inner rod (41) can be aligned with the second grouting hole (131) of the anchor body (13) under the drive of the driving mechanism (42). The control unit is connected to the acoustic wave detection mechanism (3) and the grouting positioning mechanism (4) respectively; The control unit identifies the crack segments based on the acoustic feedback data, instructs the grouting inner rod (41) to perform segmented grouting and automatic switching on the corresponding second grouting hole (131) and the sealed environment constructed by the sealing isolation component (2).

2. The controllable intelligent segmented grouting anchor bolt based on acoustic detection according to claim 1, characterized in that, The inner wall of the anchor housing (12) is provided with multiple slide rails (122) extending along the axial direction. The acoustic wave detection mechanism (3) includes a slider mechanism (31) installed on the slide rails (122). An acoustic wave detection device (32) and a power supply device are installed on the slider mechanism (31).

3. The controllable intelligent segmented grouting anchor bolt based on acoustic detection according to claim 2, characterized in that, The slider mechanism (31) includes a slider base (311), on which a slider motor (312) is mounted. The slider motor (312) is electrically connected to the power supply device. The output shaft of the slider motor (312) is connected to a drive bevel gear (313). The drive bevel gear (313) is driven by a transmission bevel gear (314). The transmission bevel gear (314) is connected to a first roller (315) perpendicular to the slider base (311). The first roller (315)... The transmission end is fixedly connected to the transmission bevel gear (314) and the rolling end is rolledly connected to one of the slide rails (122). Next to the first roller (315), there is also a second roller (316) perpendicular to the slider base (311). The transmission end of the second roller (316) passes through the slider base (311) and is connected to the transmission end of the first roller (315) through a reverse belt (317). The rolling end of the second roller (316) is rolledly connected to the other slide rail (122).

4. The controllable intelligent segmented grouting anchor bolt based on acoustic detection according to claim 3, characterized in that, The transmission ends of the first roller (315) and the second roller (316) are both provided with annular grooves (8) for mounting the reverse belt (317), and the annular grooves (8) of each roller are staggered.

5. The controllable intelligent segmented grouting anchor bolt based on acoustic detection according to claim 3, characterized in that, The drive mechanism (42) includes two lead screw support seats (421), and a lead screw (422) is provided between the two lead screw support seats (421). One end of the lead screw (422) is connected to a lead screw motor (423), and the lead screw motor (423) is signal connected to the control unit. A movable block (424) is connected to the lead screw (422), and a ball nut (412) is provided at the outer end of the grouting inner rod (41) and is fixedly connected to the movable block (424).

6. The controllable intelligent segmented grouting anchor bolt based on acoustic detection according to claim 3, characterized in that, The connecting member is a hollow tubular structure, with its two ends welded and fixed to the first grout discharge hole (121) and the second grout discharge hole (131) respectively, for guiding the grout during grouting to avoid flowing into the annular gap between the anchor rod shell (12) and the anchor rod body (13).

7. A construction method, characterized in that, Includes the following steps: S1. Drilling and preliminary anchoring: Drilling is carried out according to the designed diameter and depth. After removing the broken rock in the hole, a controllable intelligent segmented grouting anchor rod based on acoustic detection as described in any one of claims 3-6 is installed into the borehole. The anchoring end (11) is used for preliminary anchoring, and the pad (15) and the sealing ring (21) are tightened to seal the hole opening. S2. Full-hole pre-scan detection: The control unit issues an instruction to drive the slider motor (312) to drive the acoustic detection device (32) to move at a constant speed along the slide rail (122) from the anchor end (11) towards the borehole opening, and collect acoustic data on the development and distribution of fractures in the surrounding rock of the entire borehole section; S3. Fracture Identification and Intelligent Segmentation: The control unit processes the collected acoustic data, identifies the distribution locations of macroscopic and microscopic fractures by analyzing acoustic characteristics, and divides the borehole surrounding rock into several grouting segments according to the fracture distribution. S4. Formulate intelligent grouting sequence: The control unit sets the grouting priority of the micro-fracture segment located in the deep part of the borehole to be higher than that of the macro-fracture segment located in the shallow part of the borehole according to the fracture type and depth position of each segment identified in step S3, and generates a grouting sequence that switches sequentially from the anchor end (11) to the borehole opening. S5. Positioning and grouting: The control unit instructs the drive mechanism (42) to drive the grouting inner rod (41) to make axial displacement, so that the grout outlet (411) of the grouting inner rod (41) is precisely aligned with the second grouting hole (131) at the target layer corresponding to the current grouting crack segment, and the grouting pump is turned on to carry out positional grouting; S6. Dynamic monitoring and judgment: During the grouting process, the acoustic detection mechanism (3) moves back and forth in the slide rail interval corresponding to the current grouting segment to implement dynamic monitoring; the control unit determines whether the surrounding rock fissures in the grouting segment have been fully filled and consolidated by comparing the acoustic propagation characteristics before and after grouting. S7. Closed-loop automatic switching: If the current fracture segment is determined to be filled to the standard, the control unit automatically drives the grouting positioning mechanism (4) to move to the target layer corresponding to the next fracture segment; if it is not filled to the standard, grouting continues until the acoustic monitoring confirms that the segment is filled to the standard.

8. The construction method according to claim 7, characterized in that, In step S6, the filling is deemed satisfactory by comparing the current acoustic wave detection results with the original acoustic wave data before grouting. The judgment criteria include: the amplitude of the crack reflection wave after grouting is attenuated compared with that before grouting and reaches a preset threshold; the rate of change of the acoustic wave propagation speed within a preset sampling period enters a stable range; and the characteristic parameters of the echo signal conform to the preset acoustic characteristics of dense medium.

9. The construction method according to claim 7, characterized in that, After each grouting segment is determined to be filled to the standard, the control unit instructs the external grouting system to maintain the grouting pressure for 3 to 5 minutes to ensure that the grout sprayed by the grouting rod (41) is fully solidified in the surrounding rock fissure zone to prevent grout backflow, and then the switching of step S7 is performed.

10. The construction method according to claim 7, characterized in that, When the control unit determines that the last crack segment in the grouting sequence has been filled to the standard and the pressure has been maintained, the pad (15) is removed, the acoustic detection mechanism (3) is axially pulled out from the inside of the anchor bolt housing (12), and then a pre-tightening force is applied to the anchor bolt body (13) to complete the support operation.

Images