A construction method for preventing deformation of a deep foundation pit of an open-cut tunnel

Abstract

The application discloses a kind of open cut tunnel deep foundation pit anti-deformation construction methods, control feeding equipment inserts anchor rod into positioning drilling grouting equipment;Positioning drilling grouting equipment is punched to the wall of foundation pit, and anchor rod is sent into drill hole;After drilling in place, positioning drilling grouting equipment gradually exits drill hole, while concrete is injected into drill hole by positioning drilling grouting equipment, until concrete fills drill hole;Replace another position, repeat the above steps, so repeat, complete the drilling of multiple positions, anchor rod installation and concrete pouring operation;After 2.5-4 days, the concrete in each drill hole solidifies and forms anchor pile;Tighten the locking nut on the outer end of each anchor rod, and the anchor rod is tensioned on the outer support body.The application improves construction efficiency, improves the strength and service life of the anchor pile, and ensures that the outer support body pulled by the anchor pile is firmly on the corresponding wall of the foundation pit.The application is suitable for the technical field of open cut tunnel deep foundation pit anti-deformation.

Description

Technical Field

[0001] This invention belongs to the technical field of tunnel foundation pit construction, specifically, it relates to a method for preventing deformation in deep foundation pits of open-cut tunnels. Background Technology

[0002] Currently, deformation frequently occurs during the construction of deep foundation pits in open-cut tunnels, leading to construction deviations and, in more serious cases, collapses and safety accidents. To avoid these situations, anti-deformation measures for the foundation pit are necessary to ensure the accuracy and safety of construction. Generally, anchor piles are used to anchor the foundation pit to the perimeter wall, with the outer ends of the anchor piles connected to the diaphragm wall, retaining plate, or concrete piles. This allows the anchor piles to pull the diaphragm wall, retaining plate, or concrete piles in place, preventing foundation pit deformation under their support. However, during construction, unstable anchor pile rooting often results in insecure support equipment. Moreover, in the construction of anchor piles, drilling rigs are required to drill holes in the perimeter of the foundation pit. After drilling is completed, anchor rods are inserted into the drilled holes, and then concrete is poured into the holes. After the concrete solidifies, the anchor pile is formed. However, since it is impossible to ensure that the axis of the anchor rod and the anchor pile coincides, in most cases, the anchor rod is offset from the center of the anchor pile by a certain distance. As a result, when the anchor rod is tensioned, the anchor pile is often subjected to uneven stress, which affects the strength and life of the anchor pile. Summary of the Invention

[0003] This invention provides a method for preventing deformation in deep foundation pits of open-cut tunnels, which allows for the assembly of anchor bolts during drilling and ensures the alignment of the anchor bolts during the pouring process. This not only improves construction efficiency but also enhances the strength and service life of the anchor piles, ensuring that the external support structure pulled by the anchor piles is firmly attached to the corresponding foundation pit perimeter wall.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for preventing deformation in deep foundation pits of open-cut tunnels includes the following steps:

[0006] S1. Fix the anchor rod to the feeding device, control the feeding device to insert the anchor rod into the positioning drilling and grouting device, and make both ends of the anchor rod extend out of both ends of the positioning drilling and grouting device;

[0007] S2. Control the positioning drilling and grouting equipment to drill holes in the perimeter wall of the foundation pit, and as the positioning drilling and grouting equipment drills, it carries the anchor rod into the hole.

[0008] S3. After drilling into place, the positioning drilling and grouting equipment gradually withdraws from the borehole, while the anchor bolt remains inside the borehole.

[0009] S4. During the process of withdrawing the positioning drilling and grouting equipment from the borehole, concrete is injected into the borehole through the positioning drilling and grouting equipment.

[0010] S5. When the positioning drilling and grouting equipment is completely withdrawn from the borehole, the concrete fills the borehole and the concrete injection stops.

[0011] S6. Change to another location and repeat steps S1-S5. Repeat this process to complete drilling, anchor installation, and concrete pouring operations at multiple locations.

[0012] S7. After 2.5-4 days, the concrete in each borehole solidifies and forms an anchor pile.

[0013] S8. Each end of the anchor rod extending out of the outer support body is threaded with a locking nut. Tightening the locking nut will tighten the anchor rod onto the outer support body.

[0014] Furthermore, when drilling holes in the perimeter wall of the foundation pit, a positioning drilling and grouting equipment is used to drill a variable diameter hole, and the diameter of the variable diameter hole extending deep into the foundation pit is larger than its diameter near the perimeter wall of the foundation pit.

[0015] Furthermore, the external support body includes a support plate adapted to the perimeter wall of the foundation pit, the outer end of the anchor rod extends out of the support plate, and a pad is fitted on the anchor rod. Then, the locking nut is tightened so that the locking nut tensions the anchor rod and locks the locking nut onto the pad.

[0016] Furthermore, the anchor rods connected to the external support body are at least two rows, and these two rows of anchor rods are arranged at intervals in the vertical direction. Each anchor rod in the upper row extends into the soil of the pit wall in an upward inclined direction, and each anchor rod in the lower row extends into the soil of the pit wall in a downward inclined direction.

[0017] Furthermore, when drilling holes in the perimeter of the foundation pit, high-pressure water or high-pressure gas is connected to the positioning drilling and grouting equipment to cool it down, and the high-pressure water or high-pressure gas is jetted out through the front end of the positioning drilling and grouting equipment.

[0018] Furthermore, the positioning drilling and grouting equipment includes a power head that is slidably mounted on the frame via a connecting seat. The power head is connected to the drilling and grouting mechanism, and a propulsion mechanism is mounted on the connecting seat. The propulsion mechanism is drivenly connected to the frame, and an angle adjustment mechanism is mounted at the lower end of the frame.

[0019] Furthermore, the drilling and grouting mechanism includes a connecting cylinder with one end passing through and connected to the power head for transmission. A rotary drilling unit is connected to one end of the connecting cylinder near the perimeter of the pit. An anchor rod extends into the connecting cylinder along its axis, with both ends of the anchor rod extending out of both ends of the connecting cylinder. One end of the anchor rod is connected to the rotary drilling unit, and the other end of the anchor rod is connected to a sealing cap. The sealing cap is installed at the corresponding end of the connecting cylinder. A grouting component is provided at one end of the connecting cylinder near the sealing cap. The grouting component includes a distribution sleeve fitted outside the connecting cylinder. A connecting joint is constructed on the distribution sleeve, and multiple injection ports are opened on the connecting cylinder and inside the distribution sleeve.

[0020] Furthermore, the rotary drilling unit includes a movable sleeve that is movably inserted into the corresponding end of the connecting cylinder. A first guide nozzle is constructed inside the connecting cylinder and near the movable sleeve. The first guide nozzle is connected to the movable sleeve by a rigid spring disposed inside the connecting cylinder. A plurality of rotary drilling teeth are evenly arranged circumferentially at the part of the movable sleeve that extends out of the connecting cylinder. One end of each rotary drilling tooth is hinged to the end of the connecting cylinder, and the connecting cylinder is hinged to the movable sleeve by a hinge rod.

[0021] Furthermore, a support member is movably connected inside the connecting cylinder. The support member includes a threaded sleeve that is threadedly connected to the end of the anchor rod away from the drill hole. The threaded sleeve is connected to the transmission sleeve via multiple connecting rods. Multiple guide grooves are uniformly formed along the circumference of the inner wall of the connecting cylinder. Each guide groove extends along the axial direction of the connecting cylinder. Multiple guide blocks are uniformly formed along the circumference of the outer circumference of the transmission sleeve. Each guide block is slidably assembled in the corresponding guide groove.

[0022] Furthermore, the frame includes two slide rails arranged side by side, the connecting seat is slidably connected to the two slide rails, and a transmission rack is constructed on each of the slide rails; the propulsion mechanism includes a dual-axis motor, and transmission gears are respectively installed on the two output shafts of the dual-axis motor. Each transmission gear meshes with a corresponding transmission rack, and a limit plate is constructed at both ends of the axial direction of each transmission gear, and the transmission rack is restricted between the two limit plates.

[0023] The present invention, due to the aforementioned structure, achieves the following technological advancements compared to existing technologies: The present invention utilizes a feeding device to supply anchor bolts to the positioning drilling and grouting equipment, thus avoiding manual handling and alignment operations, improving assembly efficiency, and preventing alignment deviations. During drilling, the positioning drilling and grouting equipment smoothly feeds the anchor bolts into the borehole. After drilling is complete, the positioning drilling and grouting equipment leaves the anchor bolts inside the borehole during withdrawal, ensuring that the anchor bolts remain aligned with the borehole axis. Furthermore, as the positioning drilling and grouting equipment gradually withdraws, the concrete... Soil is injected into the borehole through the front end of the positioning drilling and grouting equipment. When the positioning drilling and grouting equipment is completely withdrawn from the borehole, the concrete pouring is also completed. This greatly improves construction efficiency and ensures that the structural strength of the anchored pile after solidification is enhanced. In summary, this invention can perform anchor rod assembly operations simultaneously with drilling and ensure the alignment of the anchor rods during the pouring process. This not only improves construction efficiency but also enhances the strength and service life of the anchored pile. It also ensures that the external support body pulled by the anchored pile is firmly placed on the corresponding foundation pit perimeter wall, thereby avoiding deformation of the foundation pit perimeter wall. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0025] In the attached diagram:

[0026] Figure 1 This is a schematic diagram of the structure of the positioning drilling and grouting equipment according to an embodiment of the present invention;

[0027] Figure 2 This is a structural schematic diagram of the positioning drilling and grouting equipment according to an embodiment of the present invention from another angle;

[0028] Figure 3 This is an axial structural cross-sectional view of the drilling and grouting mechanism in the positioning drilling and grouting equipment according to an embodiment of the present invention;

[0029] Figure 4 for Figure 3 Enlarged view of the structure at part A in the middle;

[0030] Figure 5 for Figure 3 Enlarged view of the structure of part B in the middle;

[0031] Figure 6 This is a partial structural cross-sectional view of the drilling and grouting mechanism in the positioning drilling and grouting equipment according to an embodiment of the present invention;

[0032] Figure 7This is a schematic diagram of the drilling and grouting mechanism in the positioning drilling and grouting equipment according to an embodiment of the present invention;

[0033] Figure 8 This is a schematic diagram of the connection between the power head, connecting seat, and distribution sleeve in the positioning drilling and grouting equipment according to an embodiment of the present invention;

[0034] Figure 9 This is a schematic diagram of the drilling and grouting mechanism in the positioning drilling and grouting equipment according to an embodiment of the present invention after removing the distribution sleeve;

[0035] Figure 10 This is a schematic diagram of the connection between the anchor bolt and the sealing cover, support, and connecting block of the positioning drilling and grouting equipment according to an embodiment of the present invention.

[0036] Figure 11 This is a schematic diagram of the transmission connection between the propulsion mechanism and the frame in a positioning drilling and grouting equipment according to an embodiment of the present invention;

[0037] Figure 12 This is a schematic diagram of the connection between the feeding device and the anchor bolt in an embodiment of the present invention;

[0038] Figure 13 This is an axial structural cross-sectional view of the anchor pile according to an embodiment of the present invention;

[0039] Figure 14 This is a schematic diagram of the connection between the external support and the anchor pile in an embodiment of the present invention.

[0040] Components labeled: 100-Frame, 101-Slide rail, 102-Transmission rack, 200-Tilt adjustment mechanism, 201-First hydraulic cylinder, 202-Second hydraulic cylinder, 203-First base, 204-Second base, 300-Connecting seat, 400-Power head, 500-Positioning drilling and grouting equipment, 501-First connecting part, 502-Second connecting part, 503-Helical blade, 504-Injection port, 505-Modible sleeve, 506-Rotary drilling tooth, 507-Hinge rod, 508-Connecting flange, 509-Second guide nozzle, 510-First guide nozzle, 511-Hard spring, 512-Connecting block, 513-Sealing cover, 514-Inner sleeve, 515-Adjustment Nut, 516-Threaded sleeve, 517-Transmission sleeve, 518-Connecting rod, 519-Guide block, 520-Guide groove, 521-Guide strip, 600-Grouting component, 601-Distribution sleeve, 602-Connecting joint, 700-Anchor rod, 701-Rod-shaped body, 702-Front end connection, 703-Rear end connection, 800-Propulsion mechanism, 801-Dual-axis motor, 802-Transmission gear, 803-Limiting disc, 900-Guide rail, 901-First telescopic rod, 902-First clamp, 903-Second telescopic rod, 904-Second clamp, 905-Linear motor, 1000-Anchor pile, 1100-Outer support body, 1101-Pan block, 1102-Locking nut. Detailed Implementation

[0041] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0042] This invention discloses a method for preventing deformation during construction of deep foundation pits in open-cut tunnels, comprising the following steps:

[0043] S1. Fix the anchor rod 700 on the feeding device, and control the feeding device to insert the anchor rod 700 into the positioning drilling and grouting device 500, with both ends of the anchor rod 700 extending out of both ends of the positioning drilling and grouting device 500.

[0044] S2. The positioning drilling and grouting equipment 500 is controlled to drill holes in the perimeter wall of the foundation pit, and as the positioning drilling and grouting equipment 500 drills, it carries the anchor rod 700 into the hole.

[0045] S3. After drilling into place, the positioning drilling and grouting equipment 500 gradually withdraws from the borehole, while the anchor rod 700 remains inside the borehole.

[0046] S4. During the process of the positioning drilling and grouting equipment 500 withdrawing from the borehole, concrete is injected into the borehole through the positioning drilling and grouting equipment 500.

[0047] S5. When the positioning drilling and grouting equipment 500 is completely withdrawn from the borehole, the concrete fills the borehole and the concrete injection stops.

[0048] S6. Change to another location and repeat steps S1-S5. Repeat this process to complete drilling, anchor bolt installation, and concrete pouring at multiple locations.

[0049] S7. After 2.5-4 days, the concrete in each borehole solidifies and forms 1000 anchor piles.

[0050] S8. Each end of the anchor rod 700 extending out of the outer support body 1100 is threaded with a locking nut 1102. Tightening the locking nut 1102 will tighten the anchor rod 700 onto the outer support body 1100.

[0051] The advantages of this invention are as follows: This invention uses a feeding device to supply the anchor rod 700 to the positioning drilling and grouting equipment 500, thus avoiding manual handling and alignment operations, improving assembly efficiency, and preventing alignment deviations. During drilling, the positioning drilling and grouting equipment 500 smoothly feeds the anchor rod 700 into the borehole. After drilling is completed, as the positioning drilling and grouting equipment 500 withdraws from the borehole, it leaves the anchor rod 700 inside, ensuring that the anchor rod 700 remains aligned with the borehole axis. Furthermore, as the positioning drilling and grouting equipment 500 gradually withdraws, concrete flows through it. The front end of the grouting device is injected into the borehole. When the positioning drilling grouting device 500 is completely withdrawn from the borehole, the concrete is poured. This greatly improves the construction efficiency and ensures that the structural strength of the anchor pile 1000 after solidification is enhanced. In summary, the present invention can perform the assembly of the anchor rod 700 while drilling, and ensure the centering of the anchor rod 700 during the pouring process. This not only improves the construction efficiency, but also enhances the strength and service life of the anchor pile 1000. It also ensures that the external support 1100 pulled by the anchor pile 1000 is firmly placed on the corresponding foundation pit perimeter wall, thereby avoiding deformation of the foundation pit perimeter wall.

[0052] In a preferred embodiment of the present invention, when drilling holes in the perimeter wall of the foundation pit, a positioning drilling and grouting device 500 is used to drill variable-diameter holes, wherein the diameter of the variable-diameter hole extending deep into the foundation pit is larger than its diameter near the perimeter wall of the foundation pit. Because the holes drilled in this invention are variable-diameter holes, and have a larger diameter located deep within the perimeter wall of the foundation pit, the anchor piles 1000 formed after pouring are as follows... Figure 13As shown in the diagram, the large-diameter end of the anchor pile 1000 extends deep into the soil layer. When anchoring and tensioning the outer support body 1100, it will not move relative to the surrounding soil layer. That is, the bonding strength between the anchor pile 1000 and the soil layer increases, and its tensioning effect on the outer support body 1100 is improved, thereby avoiding misalignment or loosening between the outer support body 1100 and the perimeter wall of the foundation pit.

[0053] As a preferred embodiment of the present invention, such as Figure 14 As shown, the outer support 1100 includes a support plate adapted to the perimeter of the pit. The outer end of the anchor rod 700 extends out of the support plate, and a pad 1101 is fitted onto the anchor rod 700. A locking nut 1102 is then tightened, causing the locking nut 1102 to tension the anchor rod 700 and lock it onto the pad 1101. In this embodiment, the anchor rods are divided into two rows, spaced apart vertically. Each anchor rod in the upper row extends into the soil of the pit perimeter in an upward inclined direction, while each anchor rod in the lower row extends into the soil of the pit perimeter in a downward inclined direction. Due to the inclined tension, the anchor rods have strong tensile strength when the support plate is subjected to the external force of pit deformation, and the unidirectional or multidirectional tensile force brought by the support plate is offset. The special design of the upper and lower rows of anchor rods in this embodiment improves the strength of the foundation pit perimeter wall, thus mitigating the risk of deformation or collapse.

[0054] In a preferred embodiment of the present invention, in order to facilitate the smooth progress of drilling and effectively reduce the heat generated during the drilling process and improve the working conditions, the following measures are taken: when drilling the perimeter of the foundation pit, high-pressure water or high-pressure gas is connected to the positioning drilling and grouting equipment 500 to cool down the positioning drilling and grouting equipment 500. The high-pressure water or high-pressure gas is jetted out through the front end of the positioning drilling and grouting equipment 500, which impacts the soil at the front end of the positioning drilling and grouting equipment 500, loosening the soil and thus improving the drilling efficiency.

[0055] As a preferred embodiment of the present invention, such as Figure 1-2As shown, the positioning drilling and grouting equipment 500 includes a frame 100, a connecting seat 300, a power head 400, a drilling and grouting mechanism, a propulsion mechanism 800, and an angle adjustment mechanism 200. The connecting seat 300 is slidably mounted on the frame 100, the power head 400 is mounted on the connecting seat 300 and connected to the drilling and grouting mechanism, the propulsion mechanism 800 is mounted on the connecting seat 300 and is drively connected to the frame 100, and the angle adjustment mechanism 200 is mounted at the lower end of the frame 100. The working principle and advantages of this invention are as follows: the anchor rod 700 is assembled into the drilling and grouting mechanism by the feeding device, and the tilt angle adjustment mechanism 200 is adjusted so that the tilt angle of the frame 100 and the drilling and grouting mechanism on it is adjusted. When the predetermined angle is reached, the power head 400 is controlled to drive the drilling and grouting mechanism to rotate. At the same time as the rotation, the propulsion mechanism 800 is controlled to move, so that the propulsion mechanism 800 drives the connecting seat 300 and the drilling and grouting mechanism on it to move together toward the perimeter wall of the foundation pit, thereby realizing the drilling and grouting mechanism to drill holes in the perimeter wall of the foundation pit, and at the same time, the anchor rod 700 is delivered into the drill hole. After drilling is completed, concrete is injected into the drilling grouting mechanism, allowing the concrete to enter the borehole from the drilling end of the mechanism. This allows the grouting mechanism to exit the borehole while simultaneously completing the pouring operation. The drilling grouting mechanism also serves a positioning function, supporting the anchor rod 700 and preventing it from tilting inside the borehole. Furthermore, this embodiment significantly improves construction efficiency, ensuring that the anchor rod 700 and the anchor pile 1000 are concentric, thereby increasing the tensile strength of the anchor pile 1000.

[0056] As a preferred embodiment of the present invention, such as Figure 3-10As shown, the drilling and grouting mechanism includes a connecting cylinder, a rotary drilling unit, and a grouting component 600. The connecting cylinder includes a first connecting portion 501 and a second connecting portion 502 connected to each other. The first connecting portion 501 is rotatably connected to the grouting component 600, and the end of the second connecting portion 502 away from the first connecting portion 501 is connected to the rotary drilling unit. A spiral blade 503 extending axially is constructed on the outer surface of the second connecting portion 502. The working principle of this embodiment is as follows: the power head 400 drives the first connecting portion 501 to rotate, which in turn drives the rotary drilling unit to rotate via the second connecting portion 502, thereby achieving rotary drilling. The function of the spiral blade 503 is to transfer the excavated soil outwards while gradually compacting this soil within the borehole's perimeter, increasing the borehole's strength and preventing borehole collapse and deformation. In this embodiment, the first connecting portion 501 of the connecting cylinder passes through and is connected to the power head 400, thus enabling the power head 400 to drive the connecting cylinder to rotate. In this embodiment, the rotary drilling unit is connected to one end of the connecting cylinder near the perimeter of the pit, i.e., to the end of the second connecting part 502 mentioned above. In this embodiment, the anchor rod 700 extends into the connecting cylinder along its axis, with both ends of the anchor rod 700 extending out of the connecting cylinder. One end of the anchor rod 700 is connected to the rotary drilling unit, and the other end is connected to the sealing cap 513, which is installed at the corresponding end of the connecting cylinder. Because the anchor rod 700 is installed inside the connecting cylinder, the connecting cylinder guides the anchor rod 700 into the borehole as the rotary drilling unit drills. By adjusting the length of the anchor rod 700 extending beyond the sealing cap 513, the anchor rod 700 causes the rotary drilling unit to deform accordingly, i.e., the outward angle of the rotary drilling unit changes, thereby changing the diameter of the drilled hole. When drilling is completed, the connection between the sealing cap 513 and the anchor rod 700 is released, and then the connecting cylinder is gradually withdrawn from the borehole, leaving the anchor rod 700 inside. In this embodiment, the grouting component 600 is located at one end of the connecting cylinder near the sealing cover 513. The grouting component 600 includes a distribution sleeve 601, which is fitted over the connecting cylinder. A connecting joint 602 is constructed on the distribution sleeve 601, and multiple injection ports 504 are provided on the connecting cylinder and inside the distribution sleeve 601. During the drilling process and withdrawal from the connecting cylinder, concrete enters the distribution sleeve 601 through the connecting joint 602, then enters the connecting cylinder through the injection ports 504, and finally enters the borehole through the end of the second connecting part 502 for pouring. During drilling operations, high-pressure water or high-pressure gas is injected into the distribution sleeve 601 through the connecting joint 602. The high-pressure water or high-pressure gas then enters the connecting cylinder through the injection port 504 from the distribution sleeve 601, and finally enters the borehole front end through the end of the second connecting part 502 of the connecting cylinder. This impacts the soil at the borehole front end and around it, loosening the soil and facilitating rotary drilling operations. It also serves a cooling function, reducing the temperature of the rotary drilling unit.In this embodiment, the sealing cap 513 seals the end of the first connecting part 501 of the connecting cylinder, thereby preventing concrete from flowing out of the borehole during grouting of the upwardly inclined borehole, which would prevent the grouting operation from being completed. Moreover, after the grouting of the upwardly inclined borehole is completed, the end of the borehole needs to be plugged.

[0057] As a preferred embodiment of the present invention, such as Figure 5-6As shown, the rotary drilling unit includes a movable sleeve 505 and a plurality of rotary drilling teeth 506. One end of the movable sleeve 505 is inserted into the second connecting portion 502 of the connecting cylinder. A connecting flange 508 is formed at the end of the movable sleeve 505 that is inserted into the connecting cylinder. A second guide nozzle 509 is formed on the inner wall of the connection between the connecting flange 508 and the movable sleeve 505. A first guide nozzle 510 is formed inside the connecting cylinder and near the movable sleeve 505. The first guide nozzle 510 is connected to the movable sleeve 505 by a rigid spring 511 disposed inside the connecting cylinder. In this embodiment, the plurality of rotary drilling teeth 506 are evenly arranged circumferentially along the portion of the movable sleeve 505 that extends out of the connecting cylinder. One end of each rotary drilling tooth 506 is hinged to the end of the connecting cylinder, and the connecting cylinder is hinged to the movable sleeve 505 by a hinge rod 507. In this embodiment, a connecting block 512 and an adjusting nut 515 are threadedly connected to both ends of the anchor rod 700 extending from the connecting cylinder. The connecting block 512 abuts against the end face of the second connecting part 502, and the adjusting nut 515 abuts against the outer end face of the sealing cover 513. By rotating the adjusting nut 515 in the forward or reverse direction, the anchor rod 700 drives the movable sleeve 505 to extend into or out of the second connecting part 502 a certain distance through the connecting block 512. During the movement of the movable sleeve 505, the movable sleeve 505 drives the rotary drilling teeth 506 to open or close through the hinge rod 507, thereby adjusting the radial length of the rotary drilling hole. In this embodiment, during drilling, a high-pressure medium (high-pressure water or high-pressure air) can be injected into the connecting cylinder. The high-pressure medium passes through the second guide nozzle 509 and the first guide nozzle 510 and enters the position where the movable sleeve 505 contacts the connecting block 512. Due to the high pressure, the movable sleeve 505 and the connecting block 512 undergo a certain displacement, and the rigid spring 511 deforms to a certain extent, thus forming a jet gap between the connecting block 512 and the movable sleeve 505. The high-pressure medium is ejected from this jet gap and impacts the soil at the borehole tip and surrounding area. In this embodiment, the second guide nozzle 509 and the first guide nozzle 510 serve two purposes: smoothing the flow and throttling and pressurizing. To improve drilling efficiency, the high-pressure medium enters the connecting cylinder in a pulsed manner and is ejected from the jet gap in a pulsed form. In this embodiment, when the drilling operation is completed, the front end of the anchor rod 700 is anchored to the end of the borehole. Then, the adjusting nut 515 is removed, and the connecting sleeve is gradually withdrawn from the borehole. The anchor rod 700 remains in the same position. In this way, the connecting block 512 changes from the state of being closed to the state of being detached from ...In this embodiment, to prevent relative rotation between the movable sleeve 505 and the second connecting part 502 from breaking the hinge point between the rotary drilling tooth 506 and the second connecting part 502, the following measures are taken: a guide bar 521 is uniformly constructed on the circumferential surface of the movable sleeve 505, and the guide bar 521 extends along the axial direction of the movable sleeve 505. A guide opening is provided at the end of the second connecting part 502, and the guide bar 521 is slidably connected to the second connecting part 502 through the guide opening.

[0058] As a preferred embodiment of the present invention, to avoid the anchor bolt 700 from tilting during insertion or removal from the connecting cylinder, such as Figure 3-4As shown in Figure 10, a support member is movably connected inside the connecting cylinder. This support member includes a threaded sleeve 516, a transmission sleeve 517, and multiple connecting rods 518. The threaded sleeve 516 and the transmission sleeve 517 are coaxially arranged, with the transmission sleeve 517 sleeved outside the threaded sleeve 516. The multiple connecting rods 518 connect and fix the threaded sleeve 516 and the transmission sleeve 517. The anchor rod 700 of this embodiment includes a rear connecting part 703, a rod-shaped body 701, and a front connecting part 702 connected sequentially along the direction of its insertion into the drill hole. The adjusting nut 515 and the threaded sleeve 516 are threadedly connected to the rear connecting part 703. An inner sleeve 514 is constructed on the sealing cover 513. The inner sleeve 514 is threadedly connected to the end of the first connecting part 501. The connecting block 512 is threadedly connected to the front connecting part 702. When it is necessary to detach the anchor rod 700 from the connecting cylinder, unscrew the adjusting nut 515, and then gradually move the connecting cylinder out of the borehole. During the outward movement, the support member maintains the state of supporting the anchor rod 700, and its relative position with the borehole remains unchanged. That is, the support member and the connecting cylinder move relative to each other. Finally, the support member is displaced to the front end of the second connecting part 502. Then rotate the connecting cylinder, so that the connecting cylinder drives the support member to rotate, and then the support member gradually detaches from the rear connecting part 703 of the anchor rod 700. When the anchor bolt 700 needs to be assembled into the connecting sleeve, first connect the front connecting part 702 of the anchor bolt 700 to the connecting block 512. Then, extend the rear connecting part 703 of the anchor bolt 700 into the connecting sleeve from the second connecting part 502. Rotate the anchor bolt 700 so that the rear connecting part 703 of the anchor bolt 700 is threadedly connected to the threaded sleeve 516 of the support member. Then, drive the anchor bolt 700 to gradually extend into the connecting sleeve until the end of the rear connecting part 703 of the anchor bolt 700 protrudes from the sealing cover 513. After that, install the adjusting nut 515 on the rear connecting part 703. Thus, it can be seen that whether the anchor bolt 700 is assembled or separated from the connecting sleeve, the support member always plays a supporting role, so that the anchor bolt 700 is always in a state of being aligned with the borehole axis. In order to achieve synchronous rotation of the support when the connecting cylinder rotates, the measures taken in this embodiment are as follows: multiple guide grooves 520 are evenly opened on the inner wall of the connecting cylinder along its circumference, each guide groove 520 extends along the axial direction of the connecting cylinder, and multiple guide blocks 519 are evenly constructed on the outer circumferential surface of the transmission sleeve 517 along its circumference, each guide block 519 being slidably assembled in the corresponding guide groove 520.

[0059] As a preferred embodiment of the present invention, such as Figure 2 , 11As shown, the frame 100 includes two slide rails 101 arranged side by side. The connecting seat 300 is slidably connected to the two slide rails 101, and a transmission rack 102 is constructed on each slide rail 101. The propulsion mechanism 800 of this embodiment includes a dual-axis motor 801, on which transmission gears 802 are respectively mounted. Each transmission gear 802 meshes with a corresponding transmission rack 102. The dual-axis motor 801 drives the two transmission gears 802 to rotate, thereby realizing the sliding of the connecting seat 300 on the frame 100. In this embodiment, in order to prevent the transmission gears 802 from disengaging from the transmission racks 102, limit disks 803 are constructed at both ends of the axial direction of each transmission gear 802. The transmission rack 102 is restricted between these two limit disks 803, thereby preventing derailment.

[0060] As a preferred embodiment of the present invention, such as Figure 2 As shown, the tilt adjustment mechanism 200 includes a first hydraulic cylinder 201 and a second hydraulic cylinder 202. The first hydraulic cylinder 201 and the second hydraulic cylinder 202 are respectively installed at both ends of the frame 100, and their upper ends are hinged to the frame 100. A first base 203 and a second base 204 are respectively mounted on the first hydraulic cylinder 201 and the second hydraulic cylinder 202, and the first base 203 and the second base 204 are supported on the ground. In this embodiment, the tilt angle of the frame 100 is adjusted by adjusting the extension and retraction of the first hydraulic cylinder 201 and the second hydraulic cylinder 202, thereby realizing the tilt drilling operation of the positioning drilling and grouting equipment 500.

[0061] As a preferred embodiment of the present invention, such as Figure 12 As shown, the feeding device includes a guide rail 900, on which a first telescopic rod 901 and a second telescopic rod 903 are provided. A first clamp 902 and a second clamp 904 are respectively installed on the first telescopic rod 901 and the second telescopic rod 903. The first telescopic rod 901 is fixedly installed on the guide rail 900, and a linear motor 905 is installed at the lower end of the second telescopic rod 903. The linear motor 905 is slidably installed on the guide rail 900 and can move on the guide rail 900. In this embodiment, the anchor bolt 700 is installed on the first clamp 902 and the second clamp 904. The first clamp 902 supports the anchor bolt 700 but does not tighten it. The second clamp 904 tightens the anchor bolt 700. By controlling the linear motor 905 to slide on the guide rail 900, the anchor bolt 700 is linearly transported and supplied to the positioning drilling and grouting equipment 500. This reduces labor intensity and ensures accurate delivery of the anchor bolt 700 to the positioning drilling and grouting equipment 500, avoiding problems such as tilting of the anchor bolt 700.

[0062] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preventing deformation during construction of deep foundation pits in open-cut tunnels, characterized in that, Includes the following steps: S1. Fix the anchor rod to the feeding device, control the feeding device to insert the anchor rod into the positioning drilling and grouting device, and make both ends of the anchor rod extend out of both ends of the positioning drilling and grouting device; S2. Control the positioning drilling and grouting equipment to drill holes in the perimeter wall of the foundation pit, and as the positioning drilling and grouting equipment drills, it carries the anchor rod into the hole. S3. After drilling into place, the positioning drilling and grouting equipment gradually withdraws from the borehole, while the anchor bolt remains inside the borehole. S4. During the process of withdrawing the positioning drilling and grouting equipment from the borehole, concrete is injected into the borehole through the positioning drilling and grouting equipment. S5. When the positioning drilling and grouting equipment is completely withdrawn from the borehole, the concrete fills the borehole and the concrete injection stops. S6. Change to another location and repeat steps S1-S5. Repeat this process to complete drilling, anchor installation, and concrete pouring operations at multiple locations. S7. After 2.5-4 days, the concrete in each borehole solidifies and forms an anchor pile. S8. Each end of the anchor rod extending out of the outer support body is threaded with a locking nut. Tightening the locking nut will tighten the anchor rod onto the outer support body. The positioning drilling and grouting equipment includes a power head that is slidably mounted on the frame via a connecting seat. The power head is connected to the positioning drilling and grouting equipment, and a propulsion mechanism is mounted on the connecting seat. The propulsion mechanism is drivenly connected to the frame, and an angle adjustment mechanism is mounted at the lower end of the frame. The positioning drilling and grouting equipment includes a connecting cylinder with one end passing through and connected to the power head for transmission. A rotary drilling unit is connected to one end of the connecting cylinder near the perimeter of the foundation pit. An anchor rod extends into the connecting cylinder along its axis, with both ends of the anchor rod extending out of both ends of the connecting cylinder. One end of the anchor rod is connected to the rotary drilling unit, and the other end of the anchor rod is connected to a sealing cap, which is installed at the corresponding end of the connecting cylinder. A grouting component is provided at one end of the connecting cylinder near the sealing cap. The grouting component includes a distribution sleeve fitted outside the connecting cylinder, with a connecting joint constructed on the distribution sleeve. Multiple injection ports are provided on the connecting cylinder and located inside the distribution sleeve. The rotary drilling unit includes a movable sleeve that is movably inserted into the corresponding end of the connecting cylinder. A first guide nozzle is constructed inside the connecting cylinder and near the movable sleeve. The first guide nozzle is connected to the movable sleeve by a rigid spring disposed inside the connecting cylinder. A plurality of rotary drilling teeth are evenly arranged circumferentially at the part of the movable sleeve that extends out of the connecting cylinder. One end of each rotary drilling tooth is hinged to the end of the connecting cylinder, and the rotary drilling tooth is hinged to the movable sleeve by a hinge rod. A support member is movably connected inside the connecting cylinder. The support member includes a threaded sleeve that is threadedly connected to the end of the anchor rod away from the drill hole. The threaded sleeve is connected to the transmission sleeve via multiple connecting rods. Multiple guide grooves are evenly formed along the circumference of the inner wall of the connecting cylinder. Each guide groove extends along the axial direction of the connecting cylinder. Multiple guide blocks are evenly formed along the circumference of the outer circumference of the transmission sleeve. Each guide block is slidably assembled in the corresponding guide groove.

2. The method for preventing deformation in deep foundation pits of open-cut tunnels according to claim 1, characterized in that: When drilling holes in the perimeter wall of the foundation pit, control the positioning drilling and grouting equipment to drill variable diameter holes, and the diameter of the variable diameter hole extending deep into the foundation pit is larger than its diameter near the perimeter wall of the foundation pit.

3. The method for preventing deformation in deep foundation pits of open-cut tunnels according to claim 1, characterized in that: The external support includes a support plate adapted to the perimeter wall of the foundation pit, the outer end of the anchor rod extends out of the support plate, and a pad is fitted on the anchor rod. Then, the locking nut is tightened so that the locking nut tensions the anchor rod and locks the locking nut onto the pad.

4. The method for preventing deformation in deep foundation pits of open-cut tunnels according to claim 1, characterized in that: The anchor rods connected to the external support body are at least two rows, and these two rows of anchor rods are arranged at intervals in the vertical direction. Each anchor rod in the upper row extends into the soil of the foundation pit wall in an upward inclined direction, and each anchor rod in the lower row extends into the soil of the foundation pit wall in a downward inclined direction.

5. The method for preventing deformation in deep foundation pits of open-cut tunnels according to claim 1, characterized in that: When drilling holes in the perimeter of the foundation pit, high-pressure water or high-pressure gas is connected to the positioning drilling and grouting equipment to cool it down, and the high-pressure water or high-pressure gas is jetted out through the front end of the positioning drilling and grouting equipment.

6. The method for preventing deformation in deep foundation pits of open-cut tunnels according to claim 1, characterized in that: The frame includes two slide rails arranged side by side, and the connecting seat is slidably connected to the two slide rails. A transmission rack is constructed on each of the slide rails. The propulsion mechanism includes a dual-axis motor. A transmission gear is installed on each of the two output shafts of the dual-axis motor. Each transmission gear meshes with a corresponding transmission rack. A limit plate is constructed at each axial end of each transmission gear, and the transmission rack is restricted between the two limit plates.

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