A slurry preservation device and method for tunnel expansive polymer grouting

Abstract

The application provides a slurry preservation device and method for tunnel expansion type polymer grouting, which is characterized in that a slurry outlet clamping seat is fixedly arranged at a main slurry outlet, and a first slurry preservation ball is pre-inserted into the clamping seat through a prefabricated PVC connecting pipe, so that the slurry preservation ball stably occupies a working position and forms an initial local slurry preservation area for the just sprayed slurry. In addition, a plurality of standby slurry preservation balls are arranged on the side of a grouting main pipe, each of the standby slurry preservation balls is equipped with an independent guide slide rail, a driving mechanism and a locking mechanism, and the standby slurry preservation balls are signal connected with the locking mechanisms through a sequential release mechanism. When the first slurry preservation ball reaches a disengagement condition and automatically exits the clamping seat, the sequential release mechanism immediately unlocks the locking mechanism of the next standby slurry preservation ball, and the slurry preservation ball gradually transitions from a side position to a middle position along the guide slide rail under the action of the driving mechanism, the PVC connecting pipe of the slurry preservation ball is automatically aligned and inserted into the same slurry outlet clamping seat, and the working position is seamlessly replaced. The sequential insertion and replacement of the slurry preservation balls around the same slurry outlet working position are realized.

Description

Technical Field

[0001] This invention relates to the field of tunnel and underground engineering grouting technology, specifically to a grout retention device and method for tunnel expansion polymer grouting. Background Technology

[0002] In grouting construction of tunnels, underground caverns, fault fracture zones, and water-rich fissures, when there is a large flow velocity or flow rate of water within the fissure, the grout, after being ejected from the grout outlet at the front end of the grouting main pipe, is often rapidly dispersed by the high-speed water flow before it can effectively retain, diffuse, or solidify. This makes it difficult for the grout to establish a stable working zone near the fissure opening, thus affecting the diffusion of the grout into the deeper parts of the fissure and the final water-blocking and reinforcement effect. In particular, expandable polymer grouts usually have strong fluidity in the pre-reaction stage, but weak erosion resistance. If the grout is washed away by a large amount of water immediately after being ejected, it often loses its due effect before it can complete effective expansion, cross-linking, gelation, or solidification, resulting in low material utilization, poor sealing effect, and large grouting volume with unstable effect.

[0003] To address the aforementioned issues, current grouting practices primarily employ the following measures: First, increasing the grouting pressure in an attempt to counteract the impact of water flow with dynamic pressure. However, excessively high grouting pressure can easily lead to rock fracturing and disordered grout diffusion, and places extremely high demands on equipment and sealing. Second, temporarily installing grout-retaining covers, grout-retaining balls, or simple baffles at the grout outlet to create a relatively still water zone and prolong the grout's residence time. However, these grout-retaining structures are mostly one-time or fixed designs. After a period of operation, a grout-retaining ball or cover often gradually loses its grout-retaining effect due to grout encapsulation, pressure buildup, or physical blockage. When the grout-retaining effect fails, construction personnel can only stop grouting, pull out the grouting pipe, replace it with a new grout-retaining component, and then reinsert it into the grouting hole. This process is time-consuming and inefficient, and the interruption of grouting can cause the injected grout to be disturbed again by water flow before it has fully solidified, severely affecting the final sealing quality.

[0004] In view of this, the inventors have specifically designed a grout retention device and method for tunnel expansion polymer grouting, which leads to this invention. Summary of the Invention

[0005] To solve the above problems, the technical solution of the present invention is as follows: A grout retention device for tunnel expansion polymer grouting includes a grouting main pipe and a main grout outlet disposed at the top of the grouting main pipe, and further includes: A slurry outlet holder and at least two slurry retaining balls are fixedly installed at the main slurry outlet. Each slurry retaining ball is prefabricated and connected to a PVC connecting pipe. Of the at least two slurry retaining balls, one serves as the first slurry retaining ball, and the others serve as standby slurry retaining balls. The first slurry retaining ball is pre-inserted into the slurry outlet holder and connected to the main slurry outlet through its PVC connecting pipe. The ends of the plurality of PVC connecting pipes are all pluggable and detachable from the insertion interface of the slurry outlet holder. The standby grout-preserving balls are respectively set in the side standby positions of the grouting main pipe. The outer wall of the grouting main pipe is fixedly provided with several axially extending guide rails. Each standby grout-preserving ball and PVC connecting pipe in each side standby position slides in cooperation with a corresponding guide rail. The lower section of the guide rail extends vertically or inclined along the side wall of the grouting main pipe, and its upper section bends and deflects towards the direction of the main grout outlet, so that the standby grout-preserving ball gradually transitions from the side position to the grout outlet seat during the upward movement. Each standby slurry-preserving ball in the standby position on each side is also equipped with a spring drive mechanism. One end of the spring drive mechanism is connected to the guide slide rail, and the other end acts directly or indirectly on the PVC connecting pipe of the standby slurry-preserving ball to apply a driving force to the standby slurry-preserving ball in the direction of the main slurry outlet. Each standby ball in the standby position on each side is also equipped with a locking mechanism, which has a locked state and an unlocked state: in the locked state, the locking mechanism constrains the standby ball in the standby position and overcomes the driving force of the spring drive mechanism; in the unlocked state, the locking mechanism causes the standby ball to move along the guide rail under the action of the spring drive mechanism. The device also includes a sequential release mechanism, which controls the locking mechanism of the next standby slurry ball by being connected to the pressure signal of the previous standby slurry ball.

[0006] Preferably, the outlet seat inlet is configured as a horn-shaped chamfered guide inlet, and the bottom of the PVC connecting pipe is provided with an inlet chamfer that cooperates with the chamfered guide inlet.

[0007] Preferably, the slurry outlet holder is provided with an axial positioning step and a sealing ring, and the outer periphery of the PVC connecting pipe is provided with a limiting step that cooperates with the axial positioning step.

[0008] Preferably, the locking mechanism includes a sliding seat and a claw assembly; the sliding seat is slidably mounted on the guide rail, and the sliding seat is provided with a limiting groove for accommodating the slurry ball, the limiting groove being arranged along the extending direction of the guide rail, and the front end of the limiting groove being provided with a guide hole for the PVC connecting pipe of the standby slurry ball to pass through; the claw assembly is installed in the limiting groove and has a locked state and an unlocked state: in the locked state, the claw assembly presses against the PVC connecting pipe of the standby slurry ball, thus locking the standby slurry ball. The slurry ball and the PVC connecting pipe are constrained within the limiting groove, so that the standby slurry ball, the PVC connecting pipe and the sliding seat are integrated and slide synchronously along the guide rail; in the unlocked state, the claw assembly disengages from the PVC connecting pipe of the standby slurry ball, releasing the PVC connecting pipe of the standby slurry ball; a positioning trigger assembly is provided at the end of the horizontal section of the guide rail, the positioning trigger assembly acts on the sliding seat to stop it from sliding, and synchronously triggers the claw assembly to switch from the locked state to the unlocked state.

[0009] Preferably, the sequential release mechanism is an electrically controlled sequential release mechanism; the electrically controlled sequential release mechanism includes a controller and an electromagnetic actuator connected to each locking mechanism in a one-to-one correspondence. The controller is signal-connected to each electromagnetic actuator and is used to issue an unlocking command to the electromagnetic actuator corresponding to the next standby locking ball in sequence according to the release signal of the previous locking ball.

[0010] Preferably, there are three grout-retaining balls, namely a first grout-retaining ball, a second grout-retaining ball, and a third grout-retaining ball; the second grout-retaining ball and the third grout-retaining ball are respectively arranged in the left and right standby positions on the main grouting pipe, and each is independently connected to the guide mechanism, the spring drive mechanism, and the locking structure.

[0011] The present invention also provides a grouting method for a grout-retaining device for tunnel expansion polymer grouting, comprising the following steps: Send the front end of the grouting main pipe into the crack opening or target working area, so that the main grout outlet faces the direction of the crack to be grouted; the first grout-retaining ball is pre-inserted into the grout outlet seat through its PVC connecting pipe and is in the working position; Grouting begins, allowing the expandable polymer grout to be sprayed out through the main grout outlet. The first grout-retaining ball forms a local grout-retaining zone for the sprayed grout, extending the grout residence and reaction time. When the first slurry retaining ball reaches the set detachment condition, its PVC connecting pipe detaches from the slurry outlet retainer and the first slurry retaining ball exits the working position. The sequential release mechanism releases the locking structure corresponding to the first standby slurry-preserving ball. Under the action of the drive mechanism, the first standby slurry-preserving ball moves along its guide mechanism, causing its PVC connecting pipe to be inserted into the same slurry outlet seat and enter the working position to take over slurry preservation. When the first standby slurry-preserving ball reaches the set disengagement condition, its PVC connecting pipe disengages from the slurry outlet seat. The sequential release mechanism releases the locking structure corresponding to the second standby slurry-preserving ball. The second standby slurry-preserving ball moves along its guide mechanism and inserts into the same slurry outlet seat, entering the working position. Repeat the above replacement process as needed until grouting is completed.

[0012] Preferably, the set disengagement conditions are: the pressure near the slurry outlet reaches a preset threshold, the limit buckle automatically releases, the elastic claw loosens, the shear connector breaks, or manual / mechanical triggering release. The technical solution provided by this invention has the following beneficial effects: This invention features a common grout outlet holder fixed at the main grout outlet. A first grout-retaining ball is pre-inserted into the holder via its prefabricated PVC connecting pipe, ensuring its stable position and creating an initial local grout-retaining area for the freshly sprayed grout. Next, multiple standby grout-retaining balls are positioned to the side of the main grouting pipe. Each standby ball is equipped with an independent guide rail, drive mechanism, and locking mechanism, and is signal-connected to each locking mechanism via a sequential release mechanism. When the first grout-retaining ball automatically exits the holder due to grout encapsulation or pressure buildup, the sequential release mechanism immediately unlocks the locking mechanism of the next standby ball. Under the action of the drive mechanism, this ball gradually transitions from the side position to the center position along the guide rail, and its PVC connecting pipe automatically aligns and inserts into the same grout outlet holder, completing a seamless handover of the working position. This process is repeated, enabling multiple grout-retaining balls to sequentially insert and replace each other around the same grout outlet position for grout retention. First, the entire grouting process does not require stopping grouting or removing the main grouting pipe, ensuring the continuity of the grouting operation and the undisturbed state of the injected grout, significantly improving construction efficiency and sealing reliability. Second, multiple grout-retaining balls take turns, providing a cumulative local grout retention time far exceeding that of a single ball, offering ample reaction window for the expandable polymer grout to complete its expansion, cross-linking, gelation, and consolidation processes. This greatly reduces the probability of the grout being washed away by water flow, significantly improving material utilization. Attached Figure Description

[0013] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0014] in: Figure 1 This is a schematic diagram of the overall structure of the device in this invention; Figure 2 This is a schematic diagram of the working structure of the second slurry-retaining ball in this invention; Figure 3 This is a schematic diagram of the working structure of the third slurry-preserving ball in this invention; Figure 4 This is a partial cross-sectional view of the slurry outlet holder and the PVC connecting pipe in this invention.

[0015] Label Explanation: In the diagram: 1. Grouting main pipe; 2. Grout outlet seat; 21. Insertion interface; 22. Chamfered guide inlet; 23. Axial positioning step; 3. First grout-retaining ball; 4. Second grout-retaining ball; 5. Third grout-retaining ball; 6. PVC connecting pipe; 61. Limiting step; 7. Guide slide rail; 71. Positioning trigger assembly; 8. Spring drive mechanism; 9. Locking mechanism; 91. Sliding seat; 92. Limiting groove. Detailed Implementation

[0016] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0017] Please see Figures 1-4 This is a preferred embodiment of the present invention for a grout retention device for tunnel expansion polymer grouting, comprising a grouting main pipe 1 and a main grout outlet disposed at the top of the grouting main pipe 1, and further comprising: A grout outlet holder 2 and at least two grout retention balls are fixedly installed at the main grout outlet. Each grout retention ball is prefabricated and connected to a PVC connecting pipe 6. Of the at least two grout retention balls, one serves as the first grout retention ball 3, and the remaining grout retention balls serve as standby grout retention balls. The first grout retention ball 3 is pre-inserted into the grout outlet holder 2 and connected to the main grout outlet through its PVC connecting pipe 6. The ends of the PVC connecting pipes 6 are all pluggable and detachable with the insertion interface 21 of the grout outlet holder 2. In this invention, there are three grout retention balls, namely the first grout retention ball 3, the second grout retention ball 4, and the third grout retention ball 5. The second grout retention ball 4 and the third grout retention ball 5 are respectively set in the standby positions on the left and right sides of the grouting main pipe 1, and are independently connected to the guide mechanism, the spring drive mechanism 8, and the locking structure.

[0018] The standby grout-preserving balls are respectively set in the side standby positions of the grouting main pipe 1. Several axially extending guide rails 7 are fixedly installed on the outer wall of the grouting main pipe 1. Each standby grout-preserving ball and PVC connecting pipe 6 in the side standby position are slidably engaged with a corresponding guide rail 7. The lower section of the guide rail 7 extends vertically or inclined along the side wall of the grouting main pipe 1, and its upper section bends towards the guide inlet of the main outlet seat 2. After the locking mechanism 9 is released, the standby grout-preserving ball rises along the guide rail 7 under the action of the spring drive mechanism 8, gradually transitioning from the side position to the middle position. This ensures that the short PVC connecting pipe 6 automatically aligns along the axial direction of the guide rail 7 and is inserted into the chamfered guide inlet 22 of the outlet seat 2, achieving seamless replacement of the grout-preserving ball. Each standby slurry-preserving ball in the standby position on each side is also equipped with a spring drive mechanism 8. One end of the spring drive mechanism 8 is connected to the guide slide rail 7, and the other end acts directly or indirectly on the PVC connecting pipe 6 of the standby slurry-preserving ball to apply a driving force to the standby slurry-preserving ball in the direction of the main slurry outlet. Each standby ball in the standby position on each side is also equipped with a locking mechanism 9. The locking mechanism 9 has a locked state and an unlocked state: in the locked state, the locking mechanism 9 constrains the standby ball in the standby position and overcomes the driving force of the spring drive mechanism 8; in the unlocked state, the locking mechanism 9 causes the standby ball to move along the guide rail 7 under the action of the spring drive mechanism 8. The device also includes a sequential release mechanism, which controls the locking mechanism 9 of the next standby slurry ball by connecting to the pressure signal of the previous standby slurry ball.

[0019] A grout outlet holder 2 is fixedly installed at the main grout outlet. This holder serves as a common insertion station. The first grout-retaining ball 3 is pre-inserted into the holder through its prefabricated PVC connecting pipe 6 and is in the working position, forming an initial local grout-retaining area for the freshly sprayed grout. The remaining standby grout-retaining balls are respectively set in the side standby positions on both sides of the grouting main pipe 1. Each standby grout-retaining ball and its PVC connecting pipe 6 are slidably engaged with the corresponding guide rail 7. The lower section of the guide rail 7 extends along the side wall of the main pipe, and the upper section bends and deflects towards the main grout outlet. At the same time, a spring drive mechanism 8 and a locking mechanism 9 are set at each standby grout-retaining ball. One end of the spring drive mechanism 8 is fixed to the guide rail 7, and the other end acts on the PVC connecting pipe 6, always applying a driving force towards the main grout outlet to the standby grout-retaining ball. The locking mechanism 9 overcomes the driving force and restrains the standby grout-retaining ball in the standby position. The device is also equipped with a sequential release mechanism, which uses the pressure generated when the previous grout-retaining ball is released. The signal connection changes, and upon detecting that the previous grout-preserving ball has dislodged from the holder, the locking mechanism 9 of the next standby grout-preserving ball is immediately switched from locked to unlocked. Under the action of the spring drive mechanism 8, the standby grout-preserving ball moves from the side position to the center position along the guide slide rail 7. Its PVC connecting pipe 6 is automatically aligned and inserted into the same grout outlet holder 2 through the bending deflection at the end of the guide slide rail 7, completing the seamless replacement of the working position. This process is repeated, with each standby grout-preserving ball taking over the work of the first grout-preserving ball 3 in turn. During the entire grouting process, there is no need to stop grouting or pull out the grouting main pipe 1, ensuring the continuity of grouting operations and the undisturbed state of the injected grout. At the same time, the successive replacement of multiple grout-preserving balls provides a local grout preservation time that far exceeds that of a single grout-preserving ball, providing a sufficient reaction window for the expandable polymer grout, enabling it to complete the expansion, cross-linking, gelation and consolidation processes. This greatly reduces the probability of the grout being washed away by water flow, significantly improving material utilization and crack sealing effect.

[0020] The inlet of the slurry outlet retainer 2 is configured as a bell-shaped chamfered guide inlet 22, the inner diameter of which gradually decreases from the outside to the inside, forming a conical guide surface. The bottom of the PVC connecting pipe 6 is provided with an inlet chamfer that cooperates with the chamfered guide inlet 22, the outer diameter of which gradually increases from front to back. When the standby slurry retaining ball, carrying its PVC connecting pipe 6, moves along the guide rail 7 to the vicinity of the slurry outlet retainer 2 under the action of the spring drive mechanism 8, the inlet chamfer first contacts the conical guide surface of the chamfered guide inlet 22. The inclined surfaces of the two generate a radial force, automatically pushing the axis of the PVC connecting pipe 6 toward the center line of the slurry outlet retainer 2, achieving initial automatic centering. As the standby slurry retaining ball continues to move forward, the inlet chamfer slides into the interior of the retainer along the conical surface of the chamfered guide inlet 22, guiding the PVC connecting pipe 6 smoothly into the insertion interface 21. The grout outlet seat 2 is further provided with an axial positioning step 23 and a sealing ring. The outer periphery of the PVC connecting pipe 6 is provided with a limiting step 61 that cooperates with the axial positioning step 23 and a sealing surface that cooperates with the sealing ring. When the PVC connecting pipe 6 is inserted to a predetermined depth, the front end face of the limiting step 61 abuts against the rear end face of the axial positioning step 23 to form an axial limit, thereby limiting the maximum insertion depth of the PVC connecting pipe 6 and ensuring that its front end maintains a precise relative position with the main grout outlet. At the same time, the sealing ring and the sealing surface form an interference fit to prevent the grout from leaking outward along the gap between the PVC connecting pipe 6 and the grout outlet seat 2. This ensures that all the grout flows through the inner hole of the PVC connecting pipe 6 to the working area at the front end of the grout ball during the grouting process. This achieves both rapid and accurate insertion and positioning between the grout ball and the grout outlet seat 2, and ensures the sealing reliability of the grouting channel after insertion, providing structural protection for the stable operation of the subsequent sequential replacement of the grout ball.

[0021] The locking mechanism 9 includes a sliding seat 91 and a claw assembly. The sliding seat 91 is slidably mounted on the guide rail 7. After bending and deflecting, the upper section of the guide rail 7 is further provided with a straight guide extension section. The axis of this extension section coincides with the axis of the insertion interface 21 of the outlet bracket 2. After the slider enters this extension section, its movement direction is forcibly constrained to be along the axis of the bracket, thereby maintaining the correct insertion posture of the PVC connecting pipe 6. An elastic buffer pad is provided at the end of the extension section to absorb the remaining kinetic energy when the slider reaches the end point, preventing the connecting pipe from shifting or rebounding due to impact. The sliding seat 91 is provided with a limiting groove 92 for accommodating the slurry ball. The limiting groove 92 is provided along the extension direction of the guide rail 7, and the top of the limiting groove 92 is for the insertion of the PVC connecting pipe 6 of the standby slurry ball. The claw assembly is installed in the limiting groove 92 and has a locked state and an unlocked state. In the initial state, the claw assembly is in the locked state, which presses against the outer wall of the PVC connecting pipe 6 of the standby slurry ball, constraining the standby slurry ball and its PVC connecting pipe 6 in the limiting groove 92, so that the standby slurry ball, the PVC connecting pipe 6 and the sliding seat 91 are integrated. At this time, although the spring drive mechanism 8 always applies a driving force towards the main slurry outlet to the sliding seat 91, due to the constraint of the claw assembly, the sliding seat 91, together with the standby slurry ball and the PVC connecting pipe 6, is fixed in the standby position and cannot move. When the sequential release mechanism sends an unlocking signal, Under the action of the spring drive mechanism 8, the sliding seat 91 drives the standby slurry ball and PVC connecting pipe 6 to slide upward from the side along the guide rail 7. When the sliding seat 91 slides to the end of the horizontal section of the guide rail 7, the positioning trigger component 71 set at the end of the horizontal section of the guide rail 7 contacts the sliding seat 91 and stops it from sliding. At the same time, the positioning trigger component 71 triggers the claw component, which switches the claw component from the locked state to the unlocked state. At this time, the claw component disengages from the contact with the PVC connecting pipe 6 of the standby slurry ball and releases the PVC connecting pipe 6. Under the action of inertia, the standby slurry ball and its PVC connecting pipe 6 continue to slide forward relative to the sliding seat 91. The front end of its PVC connecting pipe 6 passes through the limiting groove 92 and inserts into the slurry outlet bracket 2, thereby realizing that the standby slurry ball automatically takes over the working position and completes the insertion and cooperation with the slurry outlet bracket 2.

[0022] The sequential release mechanism is an electrically controlled sequential release mechanism. This mechanism includes a controller and electromagnetic actuators connected one-to-one with each locking mechanism 9. The controller is signal-connected to each electromagnetic actuator and, based on the release signal of the previous slurry-preserving ball, sequentially issues unlocking commands to the electromagnetic actuators corresponding to the next standby slurry-preserving ball. Specifically, a pressure sensor is installed at the slurry outlet holder 2, which monitors the pressure changes within the slurry outlet holder 2 in real time. When a slurry-preserving ball in the working position releases from the slurry outlet holder 2 after completing its slurry-preserving task, the pressure value within the slurry outlet holder 2 changes accordingly. The pressure sensor converts this pressure change signal into an electrical signal and transmits it to the controller. Upon receiving this signal, the controller sends an unlocking command to the electromagnetic actuator corresponding to the next standby slurry-preserving ball according to a preset sequential logic. The electromagnetic actuator is installed at the corresponding locking mechanism 9. Upon receiving the unlocking command from the controller, the electromagnetic actuator is energized to generate electromagnetic force, driving the claw assembly of the locking mechanism 9 to move, switching it from the locked state to the unlocked state. The controller has a pre-set sequential control program that sends unlocking commands sequentially according to the arrangement of the standby grout-preserving balls. When the locking mechanism 9 of the first standby grout-preserving ball is unlocked, the ball moves along the guide rail 7 towards the grout outlet seat 2 under the action of the spring drive mechanism 8, and its PVC connecting pipe 6 is inserted into the grout outlet seat 2 and enters the working position. When the ball finishes its work and detaches from the grout outlet seat 2, the pressure sensor detects a pressure change signal again and transmits it to the controller. The controller then issues the next unlocking command, releasing the locking mechanism 9 of the second standby grout-preserving ball. This process continues until all standby grout-preserving balls have completed their turn. Through the above-mentioned electrically controlled sequential release mechanism, the automatic control of the sequential replacement of grout-preserving balls is achieved. This mechanism offers fast response, high control accuracy, and eliminates the need for manual intervention, further improving the continuity and reliability of grouting operations.

[0023] The present invention also provides a grouting method for a grout-retaining device for tunnel expansion polymer grouting, comprising the following steps: First, the front end of the grouting main pipe 1 is inserted into the fissure opening or target working area, so that the main grout outlet faces the direction of the fissure to be grouted. At this time, the first grout-retaining ball 3 is pre-inserted into the grout outlet retainer 2 through its PVC connecting pipe 6, stably occupying the working position. Then, grouting begins, and the expanding polymer grout is sprayed out through the main grout outlet. The first grout-retaining ball 3 forms a local grout-retaining area in front of the grout outlet, forming the first local barrier and grout-retaining effect on the freshly sprayed grout, so as to reduce the direct scouring of the initial grout by the large flow of water from the fissure, prolong the residence and reaction time of the grout near the grout outlet, and allow the grout to obtain the initial reaction window period. When the first grout-retaining ball 3 reaches the set detachment condition due to grout encapsulation, pressure accumulation, or physical blockage, its PVC connecting pipe 6 automatically detaches from the grout outlet retainer 2, and the first grout-retaining ball 3 exits the working position. At this time, the pressure sensor at the grout outlet retainer 2 detects the pressure change signal and transmits it to the controller. The controller then... According to the preset sequence logic, an unlocking command is sent to the electromagnetic actuator corresponding to the first standby grout-preserving ball. The electromagnetic actuator is energized, switching the locking mechanism 9 of the first standby grout-preserving ball from the locked state to the unlocked state. Under the action of the spring drive mechanism 8, the standby grout-preserving ball moves along the guide slide rail 7 from the standby position on the side of the grouting main pipe 1 towards the main grout outlet. Its PVC connecting pipe 6 is automatically aligned and inserted into the same grout outlet bracket 2 by the bending deflection at the end of the guide slide rail 7, and enters the working position to take over grout preservation. When the first standby grout-preserving ball also meets the set disengagement conditions, its PVC connecting pipe 6 is disengaged from the grout outlet bracket 2. The controller then sends the next unlocking command to release the locking mechanism 9 corresponding to the second standby grout-preserving ball. The second standby grout-preserving ball moves along its guide slide rail 7 in the same way and inserts into the same grout outlet bracket 2, and enters the working position. This process continues in sequence until all standby grout-preserving balls have completed their replacement, and the grouting is completed. Throughout the grouting process, multiple grout-retaining balls sequentially complete the process of "pre-insertion work - disengagement and withdrawal - next ball movement and alignment - insertion into the working position - disengagement and withdrawal again - next ball taking over" around the same grout outlet seat 2. This process does not require stopping grouting or removing the main grouting pipe 1, ensuring the continuity of grouting operations and the undisturbed state of the injected grout. The cumulative local grout retention time provided by multiple grout-retaining balls far exceeds that of a single grout-retaining ball, providing a sufficient reaction window for the expandable polymer grout to complete the expansion, cross-linking, gelation and consolidation processes. This greatly reduces the probability of the grout being washed away by water flow and significantly improves material utilization and crack sealing effect.

[0024] In summary, this invention fixes a common slurry outlet holder 2 at the main slurry outlet and pre-inserts the first slurry-retaining ball 3 into the holder via its prefabricated PVC connecting pipe 6, ensuring its stable occupation of the working position and forming an initial local slurry-retaining area for the freshly sprayed slurry. Secondly, multiple standby slurry-retaining balls are positioned to the side of the main grouting pipe 1. Each standby slurry-retaining ball is equipped with an independent guide rail 7, a drive mechanism, and a locking mechanism 9, and is signal-connected to each locking mechanism 9 via a sequential release mechanism. When the first slurry-retaining ball 3 automatically exits the holder due to slurry encapsulation or pressure accumulation, the sequential release mechanism immediately unlocks the locking mechanism 9 of the next standby slurry-retaining ball. Under the action of the drive mechanism, this slurry-retaining ball gradually transitions from the side position to the center position along the guide rail 7, and its PVC connecting pipe 6 automatically aligns and inserts into the same slurry outlet holder 2, completing a seamless handover of the working position. This process is repeated, enabling multiple slurry-retaining balls to be sequentially inserted and replaced around the same slurry outlet position for slurry retention. First, the entire grouting process does not require stopping grouting or removing the main grouting pipe 1, ensuring the continuity of the grouting operation and the undisturbed state of the injected grout, significantly improving construction efficiency and sealing reliability. Second, multiple grout-retaining balls take turns, providing a cumulative local grout retention time far exceeding that of a single ball, offering ample reaction window for the expandable polymer grout to complete its expansion, cross-linking, gelation, and consolidation processes. This greatly reduces the probability of the grout being washed away by water flow, significantly improving material utilization.

[0025] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A grout retention device for tunnel expansion polymer grouting, comprising a grouting main pipe and a main grout outlet disposed at the top of the grouting main pipe, characterized in that, Also includes: A slurry outlet holder and at least two slurry retention balls are fixedly installed at the main slurry outlet, and each slurry retention ball is prefabricated and connected to a PVC connecting pipe; Of the at least two slurry-holding balls, one serves as the first slurry-holding ball, and the remaining slurry-holding balls serve as standby slurry-holding balls. The first slurry-holding ball is pre-inserted into the slurry outlet bracket and connected to the main slurry outlet via its PVC connecting pipe. The ends of the plurality of PVC connecting pipes are all pluggable and detachable from the insertion interface of the slurry outlet bracket. The standby grout-preserving balls are respectively set in the side standby positions of the grouting main pipe. The outer wall of the grouting main pipe is fixedly provided with several axially extending guide rails. Each standby grout-preserving ball and PVC connecting pipe in each side standby position slides in cooperation with a corresponding guide rail. The lower section of the guide rail extends vertically or inclined along the side wall of the grouting main pipe, and its upper section bends and deflects towards the direction of the main grout outlet, so that the standby grout-preserving ball gradually transitions from the side position to the grout outlet seat during the upward movement. Each standby slurry-preserving ball in the standby position on each side is also equipped with a spring drive mechanism. One end of the spring drive mechanism is connected to the guide slide rail, and the other end acts directly or indirectly on the PVC connecting pipe of the standby slurry-preserving ball to apply a driving force to the standby slurry-preserving ball in the direction of the main slurry outlet. Each standby ball in the standby position on each side is also equipped with a locking mechanism, which has a locked state and an unlocked state: in the locked state, the locking mechanism constrains the standby ball in the standby position and overcomes the driving force of the spring drive mechanism; in the unlocked state, the locking mechanism causes the standby ball to move along the guide rail under the action of the spring drive mechanism. The device also includes a sequential release mechanism, which controls the locking mechanism of the next standby slurry ball by being connected to the pressure signal of the previous standby slurry ball.

2. The grout retention device for tunnel expansion polymer grouting according to claim 1, characterized in that, The outlet slot inlet is configured as a horn-shaped chamfered guide inlet, and the bottom of the PVC connecting pipe is provided with an inlet chamfer that cooperates with the chamfered guide inlet.

3. A grout retention device for tunnel expansion polymer grouting according to claim 2, characterized in that, The slurry outlet holder is provided with an axial positioning step and a sealing ring, and the outer periphery of the PVC connecting pipe is provided with a limiting step that cooperates with the axial positioning step.

4. A grout retention device for tunnel expansion polymer grouting according to claim 1, characterized in that, The locking mechanism includes a sliding seat and a claw assembly. The sliding seat is slidably mounted on the guide rail and has a limiting groove for accommodating the slurry-preserving ball. The limiting groove is located along the extension direction of the guide rail, and the top of the limiting groove is for the insertion of the PVC connecting pipe of the standby slurry-preserving ball. The claw assembly is installed in the limiting groove and has a locked state and an unlocked state. In the locked state, the claw assembly presses against the PVC connecting pipe of the standby slurry-preserving ball, constraining the standby slurry-preserving ball and the PVC connecting pipe within the limiting groove, so that the standby slurry-preserving ball, the PVC connecting pipe, and the sliding seat form an integral part and slide synchronously along the guide rail. In the unlocked state, the claw assembly disengages from the PVC connecting pipe of the standby slurry-preserving ball, releasing the PVC connecting pipe. A positioning trigger assembly is provided at the end of the horizontal section of the guide rail. The positioning trigger assembly acts on the sliding seat to stop its sliding and simultaneously triggers the claw assembly to switch from the locked state to the unlocked state.

5. A grout retention device for tunnel expansion polymer grouting according to claim 1, characterized in that, The sequential release mechanism is an electrically controlled sequential release mechanism; the electrically controlled sequential release mechanism includes a controller and an electromagnetic driver connected to each locking mechanism in a one-to-one correspondence. The controller is signal-connected to each electromagnetic driver and is used to issue an unlocking command to the electromagnetic driver corresponding to the next standby locking ball in sequence according to the release signal of the previous locking ball.

6. A grout retention device for tunnel expansion polymer grouting according to claim 1, characterized in that, The number of grout-retaining balls is three, namely the first grout-retaining ball, the second grout-retaining ball, and the third grout-retaining ball; the second grout-retaining ball and the third grout-retaining ball are respectively set in the left and right standby positions on the main grouting pipe, and are independently connected to the guide mechanism, the spring drive mechanism, and the locking structure.

7. A grouting method using a grout-retaining device for tunnel expansion polymer grouting according to any one of claims 1-6, characterized in that, Includes the following steps: Send the front end of the grouting main pipe into the crack opening or target working area, so that the main grout outlet faces the direction of the crack to be grouted; the first grout-retaining ball is pre-inserted into the grout outlet seat through its PVC connecting pipe and is in the working position; Grouting begins, allowing the expandable polymer grout to be sprayed out through the main grout outlet. The first grout-retaining ball forms a local grout-retaining zone for the sprayed grout, extending the grout residence and reaction time. When the first slurry retaining ball reaches the set detachment condition, its PVC connecting pipe detaches from the slurry outlet retainer and the first slurry retaining ball exits the working position. The sequential release mechanism releases the locking structure corresponding to the first standby slurry-preserving ball. Under the action of the drive mechanism, the first standby slurry-preserving ball moves along its guide mechanism, causing its PVC connecting pipe to be inserted into the same slurry outlet seat and enter the working position to take over slurry preservation. When the first standby slurry-preserving ball reaches the set disengagement condition, its PVC connecting pipe disengages from the slurry outlet seat. The sequential release mechanism releases the locking structure corresponding to the second standby slurry-preserving ball. The second standby slurry-preserving ball moves along its guide mechanism and inserts into the same slurry outlet seat, entering the working position. Repeat the above replacement process as needed until grouting is completed.

8. A grouting method for tunnel expansion polymer grouting according to claim 7, characterized in that, The set disengagement conditions are: the pressure near the slurry outlet reaches a preset threshold, the limit buckle is automatically released, the elastic claw is loosened, the shearing connector is disconnected, or the release is triggered manually or mechanically.

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