Weak surrounding rock tunnel excavation method and auxiliary equipment thereof

Abstract

The invention provides a weak surrounding rock tunnel excavation method and auxiliary equipment thereof. The weak surrounding rock tunnel excavation method comprises the following steps that a position is designed to construct an advanced small guide pipe, and a lower step and an upper step are divided; a plurality of glass fiber ribs are constructed in an upper step area; concrete is sprayed on the tunnel face and an unsupported area near the tunnel face for sealing, and a grout stopping wall is formed; grouting is conducted through glass fiber ribs; grouting is completed, the design strength is achieved, and an upper step is excavated and constructed; after excavation is completed, primary spraying construction is carried out, then steel frame and anchor rod construction is carried out, and after steel frame and anchor rod construction is completed, re-spraying construction is carried out; a lower step is excavated and supported, and one cycle operation is completed; and repeating the steps until the whole construction is completed. Through advanced grouting reinforcement of the glass fiber ribs, a stable reinforcement body is formed by the tunnel face and the surrounding rock; and compared with a traditional grouting steel floral tube, the glass fiber rib structure is easy to cut by a cantilever type heading machine, multiple disturbances to weak surrounding rock can be reduced, and the construction safety is further improved.

Description

Technical Field

[0001] This invention relates to the field of tunnel excavation technology in weak surrounding rock, and specifically to a method for tunnel excavation in weak surrounding rock and its auxiliary equipment. Background Technology

[0002] In highway tunnel construction, Class V soft surrounding rock has always been a challenging engineering problem due to its low strength, poor stability, and tendency to soften and disintegrate when exposed to water. Currently, three-lane highway tunnels in Class V soft surrounding rock are generally constructed using the double-sidewall pilot tunnel method or the CD method (central diaphragm wall method). The core idea of ​​these traditional methods is to divide the large-section tunnel into multiple smaller sections for excavation and then gradually support and shape them.

[0003] However, traditional construction methods have many unavoidable drawbacks:

[0004] If the surrounding rock is weak and has poor stability, it will be disturbed multiple times during the multi-section excavation process, which will easily cause collapse and deformation, resulting in an over-excavation rate of 15%-20%. This not only increases the amount of slag removal work, but also requires a large amount of additional shotcrete, steel bars and other support materials, which will significantly increase the project cost. Moreover, the safety risks are prominent: on the one hand, the face lacks effective pre-reinforcement during multi-section excavation, which makes it prone to collapse due to the instability of the surrounding rock, threatening the safety of construction workers; on the other hand, traditional construction methods require the installation of a large number of temporary supports (such as intermediate partition walls and temporary invert arches). When the temporary supports are removed later, the surrounding rock is prone to secondary deformation or even collapse due to stress redistribution, posing extremely high safety risks. As highway construction extends into mountainous areas, the proportion of Class V soft rock tunnels is increasing year by year, and traditional construction methods can no longer meet the comprehensive requirements of modern engineering for construction efficiency, safety, and cost. Summary of the Invention

[0005] The main objective of this invention is to provide a method for excavating tunnels in weak surrounding rock and its auxiliary equipment, thereby solving the problems of high construction difficulty, high material consumption, easy collapse of the tunnel face, and high construction risk caused by the existing method of excavating tunnels in weak surrounding rock in sections.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for tunnel excavation in weak surrounding rock includes the following steps: S1. Construct advanced small guide pipes at the designed location, and divide the lower and upper steps; S2. Multiple fiberglass reinforcement bars are installed in the upper step area; S3. The unsupported area at and near the working face is sealed with shotcrete to form a grout-stopping wall; S4. Grouting via fiberglass reinforcement; S5. Grouting is completed and reaches the design strength, then the upper step excavation construction begins; S6. After the excavation is completed, the initial spraying is carried out, followed by the construction of the steel frame and anchor bolts. After the construction of the steel frame and anchor bolts is completed, the re-spraying is carried out. S7. Excavation and support of the lower step, completing one cycle of operation; S8. Repeat S1-S7 until the entire tunnel construction is completed.

[0007] In the preferred embodiment, in step S2, auxiliary equipment is first set up to locate the construction position of the glass fiber reinforcement. Auxiliary equipment is used to isolate construction workers from the working face. In the event of a collapse of the working face due to the construction of fiberglass reinforcement, the auxiliary equipment is used to isolate the workers and ensure their safety. A space is reserved between the auxiliary equipment and the working face to allow space for concrete spraying in S3.

[0008] In the preferred embodiment, the glass fiber reinforcement includes hollow reinforcement and solid reinforcement, which are alternately arranged. The solid reinforcement is used to increase the strength of the construction site, and the hollow reinforcement is used for grouting.

[0009] In the preferred embodiment, in S4, the grouting construction sequence is from the outer ring of the working face to the inner ring.

[0010] An auxiliary device for a method of tunnel excavation in weak surrounding rock includes a bottom plate, and a support beam is provided on the top of the bottom plate. The shape of the support beam is adapted to the tunnel. The base plate is equipped with an extension plate, and both the extension plate and the base plate are equipped with rollers to assist in the movement of the equipment. The inner side of the support beam is equipped with a protective plate, and the protective plate has several guide holes. The guide hole is used to guide the construction of the glass fiber reinforcement.

[0011] In a preferred embodiment, the base plate is provided with a sliding structure, and the sliding structure is provided with a lifting mechanism. The sliding structure is used to drive the lifting mechanism to move vertically and horizontally along the base plate. The lifting mechanism is equipped with a clamping device at the top, which is used to assist in clamping the fiberglass reinforcement or the shotcrete spray gun.

[0012] In a preferred embodiment, the sliding structure includes several slide rails disposed on the top of the base plate, the slide rails being arranged along the length direction of the base plate; The sliding end of the slide rail is provided with a sliding plate, and the top of the sliding plate is provided with two fixing sleeves along the width direction of the base plate. The two fixing sleeves are located at the edge of the sliding plate. A movable plate is slidably connected between the two fixed sleeves, and a fixed plate is provided on the top side of the movable plate near the fixed sleeve; The top of the sliding plate is provided with a positioning groove, and the bottom of the movable plate is provided with a T-shaped sliding block that is slidably connected to the inside of the positioning groove; the T-shaped sliding block is adapted to the positioning groove. The fixed sleeve has a groove on the side near the movable plate, and a slider is slidably connected in the groove. The slider is fixedly connected to the fixed plate. A second motor is provided at the end of the slide, and the output shaft of the second motor is provided with a second threaded rod, which passes through the slider and is threadedly connected to the slider.

[0013] In a preferred embodiment, the lifting mechanism includes a support sleeve fixed to the top of the movable plate, and a movable seat is slidably connected inside the support sleeve; The top of the movable seat is equipped with a hydraulic rod; the clamping element is connected to the output end of the hydraulic rod; The top of the support sleeve is provided with a top plate, through which the hydraulic rod passes; The side of the support sleeve is provided with several fixing shells; A third motor is provided on the top of the fixed housing, and the output shaft of the third motor is provided with a third threaded rod; The third threaded rod is threadedly connected to a connecting block, which is slidably connected inside the fixed shell; The connecting block and the movable seat are connected by a connecting plate; The fixed shell and support sleeve are provided with grooves for the sliding of the connecting block and the connecting plate.

[0014] In a preferred embodiment, the clamping component includes a fixed base, and the fixed base is provided with grippers; The fixed base is equipped with a reducer and a fourth motor. The output shaft of the fourth motor is connected to the input shaft of the reducer, and the output shaft of the reducer is connected to the gripper. The mounting base is equipped with a protective shell, which covers the reducer and the fourth motor.

[0015] In the preferred embodiment, a guide plate is provided on the inner side of the support beam, located below the protective plate; The guide plate slides between the first position and the second position. When it slides to the first position, the guide plate is tilted and positioned below the protective plate. At this time, the edge of the guide plate is close to the edge plate of the support beam and is used to block the lower end of the protective plate on the side close to the working face. When it slides to the second position, the guide plate slides to the bottom of the support beam and is close to or in a vertical state. The connection structure between the support beam and the guide plate includes a first guide groove and a second guide groove located inside the support beam. The second guide groove is a vertical groove and is located near the edge of the support beam. The first guide groove and the second guide groove are connected and smoothly joined; The support beam is equipped with a movable groove, which is connected to the second guide groove; A first motor is installed inside the support beam, and the output shaft of the first motor is provided with a first threaded rod, which passes through a movable groove. The movable groove is equipped with a guide rod and a movable block is slidably connected thereto. Both the guide rod and the first threaded rod pass through the movable block. The movable block is threadedly connected to the first threaded rod and slidably connected to the guide rod. The guide plate has a first guide block and a second guide block on its edge; The first guide block is near the top of the guide plate and is slidably connected to the inside of the first guide groove; the second guide block is near the bottom of the guide plate and is slidably connected to the inside of the second guide groove. The second guide block is equipped with a fixed shaft, which is rotatably connected to the inside of the movable block.

[0016] This invention provides a method for tunnel excavation in weak surrounding rock and its auxiliary equipment. By adopting the above solution, the following beneficial effects are achieved: The two-stage step method is used for excavation, which is divided into only two sections. Compared with the multi-section excavation of the double-sidewall pilot tunnel method, the process is simplified and the efficiency is higher.

[0017] By using fiberglass reinforcement for pre-grouting, a stable reinforced body is formed at the tunnel face and around the rock. During excavation, the deformation of the surrounding rock is controlled within 5cm, reducing over-excavation rate, material loss, and project cost.

[0018] Compared with traditional grouting steel pipes, the fiberglass reinforced structure is easier to cut with a cantilever tunneling machine, which can reduce repeated disturbance to the weak surrounding rock and further increase construction safety.

[0019] The protective plates and guide plates of the auxiliary equipment form a physical isolation, which can increase the reaction time of construction workers and ensure their safety even if there is a partial collapse at the working face.

[0020] Fiberglass reinforcement bars are precisely positioned through the guide holes of auxiliary equipment, and the grouting sequence proceeds from the outer ring to the inner ring to ensure uniform grout diffusion and consistent surrounding rock reinforcement effect; timely support after excavation forms a complete initial support system, effectively controlling long-term deformation of the surrounding rock.

[0021] It is not only applicable to three-lane highway tunnels in Class V soft surrounding rock, but can also be applied to the construction of two-lane and four-lane tunnels in Class IV-V soft surrounding rock by adjusting parameters according to the tunnel cross-section size and surrounding rock grade, making it highly applicable. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a structural schematic diagram of the present invention during construction; Figure 2 This is a schematic diagram of the working face of the present invention; Figure 3 This is a schematic diagram of the auxiliary device of the present invention. Figure 1 ; Figure 4 This is a schematic diagram of the auxiliary device of the present invention. Figure 2 ; Figure 5 This is a schematic diagram of the auxiliary device of the present invention. Figure 3 ; Figure 6 This is a schematic diagram of the sliding structure and lifting mechanism of the present invention; Figure 7 This is a cross-sectional structural diagram of the lifting mechanism of the present invention; Figure 8 This is a cross-sectional view of the fixing sleeve of the present invention; Figure 9 This is a schematic diagram of the structure of the first guide groove of the present invention; Figure 10 This is a cross-sectional view of the connection between the guide plate and the support beam of the present invention; In the picture: 101 lower step, 102 upper step, 2 fiberglass reinforcement, 201 hollow reinforcement, 202 solid reinforcement, 203 arched reinforcement, 3 support beam, 4 protective plate, 401 guide hole, 5 base plate, 501 extension plate, 502 roller, 6 guide plate, 601 first guide groove, 602 second guide groove, 603 movable groove, 604 first guide block, 605 second guide block, 606 movable block, 607 fixed shaft, 608 guide rod, 609 first motor, 610 first threaded rod, 7 sliding structure, 701 slide rail, 7 sliding plate 02, Movable plate 703, Fixed plate 704, Positioning groove 705, Fixed sleeve 706, Slide groove 707, Slider 708, Second motor 709, Second threaded rod 710, Lifting mechanism 8, Support sleeve 801, Movable seat 802, Hydraulic rod 803, Top plate 804, Fixed shell 805, Third motor 806, Third threaded rod 807, Connecting block 808, Connecting plate 809, Clamping part 9, Fixed seat 901, Gripper 902, Reducer 903, Fourth motor 904, Protective shell 905. Detailed Implementation

[0023] Example 1: like Figure 1 and 2 As shown, a method for tunnel excavation in weak surrounding rock includes the following steps: S1. Advance preparation and step division: Pre-construction small guide pipes are installed within the 120°-150° range of the arch of the tunnel's designed excavation outline. These small guide pipes are made of seamless steel pipes with a diameter of φ42mm × 3.5mm, a length of 4-5m, a circumferential spacing of 30-40cm, and an external insertion angle of 5°-10°. They are used for preliminary reinforcement of the surrounding rock ahead of the tunnel face. Based on the tunnel cross-section dimensions, such as a three-lane highway tunnel with a width of 14-16m and a height of 5-6m, lower step 101 and upper step 102 are divided. The upper step height is 2.5-3m, and the lower step height is 2.5-3m. The step length is controlled at 5-8m to avoid excessive step length leading to surrounding rock instability.

[0024] S2. Construction of Fiberglass Reinforcement on the Upper Step: First, a special auxiliary device is set up in the tunnel. The construction position of the fiberglass reinforcement 2 is accurately located through the guide hole 401 of the auxiliary device. The fiberglass reinforcement 2 is laid along the arch and side wall of the upper step, with a circumferential spacing of 40-50cm and a longitudinal spacing of 3-4m, and an insertion depth of 3-4m into the surrounding rock. During the construction, the protective plate 4 of the auxiliary device isolates the construction personnel from the working face. If the construction of the fiberglass reinforcement 2 causes a local collapse of the working face, the protective plate 4 can block the collapse from impacting the construction personnel, increase the reaction time of the construction personnel, and ensure safety. At the same time, a 30-50cm operating space is reserved between the auxiliary device and the working face for subsequent concrete spraying construction.

[0025] S3. Grout-stopping wall sealing: Wet shotcrete process is used to spray and seal the unsupported area within 1-5m of the working face to form a grout-stopping wall; the shotcrete strength grade is C25-C30 and the thickness is 10-15cm to ensure that the grout-stopping wall has good sealing performance, prevent grout leakage during subsequent grouting process, and improve the grouting reinforcement effect.

[0026] S4. Grouting reinforcement: Grouting is carried out through the hollow bars 201 in the glass fiber reinforcement 2. The preferred grouting material is cement-water glass double liquid grout, with a cement grout to water glass volume ratio of 1:0.8-1:1, a cement grout water-cement ratio of 0.8:1-1:1, a water glass concentration of 35-40°Be′, and a grouting pressure controlled at 1.5-2.5MPa. The grouting construction sequence is from the outer ring of the working face to the inner ring. First, a sealed reinforcement ring is formed by grouting the outer ring, and then the inner ring of surrounding rock is permeated and reinforced to ensure that the grout is evenly diffused in the cracks of the surrounding rock to form a complete reinforced body.

[0027] S5. Upper Bench Excavation: After grouting is completed, it should be cured for more than 60 hours. After the grout strength reaches the design strength, the upper bench 102 excavation construction should be carried out. The excavation is preferably carried out using a cantilever tunneling machine to avoid the disturbance of the surrounding rock caused by blasting excavation. The excavation cycle advance should be controlled at 1-1.5m / cycle.

[0028] S6. Upper Bench Support: After the upper bench excavation is completed, initial shotcrete construction is carried out immediately, with an initial shotcrete thickness of 4-6cm, to quickly seal the surrounding rock and prevent it from being exposed and weathered. After the initial shotcrete is completed, an I-beam steel frame is erected with a circumferential spacing of 40-50cm, corresponding to the position of the glass fiber reinforcement bar 2. At the same time, system anchor bolts are constructed and welded to the steel frame. After the steel frame and anchor bolts are constructed, secondary shotcrete construction is carried out, with the total thickness of the secondary shotcrete reaching 25-30cm, forming a complete initial support system.

[0029] S7. Lower Step Construction: After the upper step support is completed and the concrete strength reaches 70% of the design strength, the lower step 101 is excavated. The lower step is excavated in two sections, with a spacing of 3-5m between the two sections, to avoid the instability of the surrounding rock caused by full-section excavation. After the lower step is excavated, it is supported according to the same support standard as the upper step to complete a complete construction cycle.

[0030] S8. Cyclic Advancement: Repeat the construction steps of S1-S7, gradually advancing until the overall excavation and support construction of the tunnel is completed.

[0031] Compared with traditional grouting steel pipes, the fiberglass reinforced structure is easier to cut with a cantilever tunneling machine, which can reduce repeated disturbance to weak surrounding rock and increase construction safety.

[0032] Example 2: like Figure 3 , 4 As shown in Figures 5, 6, 7, 8, 9, and 10, to complement the above excavation method, this invention also provides an auxiliary device for tunnel excavation in weak surrounding rock, which has multiple functions such as fiberglass reinforcement positioning, worker protection, and tool clamping. The specific structure is as follows: The system includes a base plate 5, which is a rectangular steel plate with a length adapted to the tunnel width. An extension plate 501, made of the same material as the base plate, is welded to one side of the base plate 5. Both the extension plate 501 and the bottom of the base plate 5 are equipped with rollers 502, preferably heavy-duty omnidirectional wheels with braking function, or motorized engineering rollers, to facilitate the movement of auxiliary equipment in the tunnel. A support beam 3 is welded to the top of the base plate 5. The support beam 3 is arched and adapted to the tunnel cross-section, and is used to support components such as the protective plate 4 and the guide plate 6, ensuring the overall rigidity of the equipment.

[0033] Protective and positioning components: A protective plate 4 is bolted to the inner side of the support beam 3. The protective plate 4 is made of wear-resistant steel and its shape is adapted to the support beam 3. Specifically, it can be seen that... Figure 3 , 4 As shown in Figure 5, the protective plate 4 has several guide holes 401 evenly distributed on it. The diameter of the guide holes 401 is 5-8 mm larger than the diameter of the glass fiber reinforcement 2. The hole positions correspond one-to-one with the designed construction positions of the glass fiber reinforcement 2, which are used to guide the glass fiber reinforcement 2 to be accurately implanted into the surrounding rock. The function of the protective plate 4 is to isolate the construction personnel from the working face. When the working face collapses, it can block the impact of the collapsed body and ensure the safety of the construction personnel. At the same time, the construction position of the glass fiber reinforcement 2 can be guided and determined through the guide holes 401.

[0034] The inner side of the support beam 3 is provided with a guide plate 6 located below the protective plate 4. The guide plate 6 is made of steel and can slide between the first position and the second position. The connection structure between the support beam 3 and the guide plate 6 includes: When slid to the first position, the guide plate 6 is inclined and positioned below the protective plate 4. The edge of the guide plate 6 is close to the edge plate of the support beam 3, which is used to block the lower end of the protective plate 4 on the side close to the working face, thereby reducing the speed and amount of collapsed debris falling from below the protective plate 4. When slid to the second position, the guide plate 6 slides to the bottom end of the support beam 3 and is close to or in a vertical state, without occupying the operating space for shotcrete construction.

[0035] It also includes a first guide groove 601 and a second guide groove 602 located inside the support beam 3. The second guide groove 602 is a vertical groove located near the edge of the support beam 3. The first guide groove 601 is an arc groove that communicates with the second guide groove 602 and is smoothly connected to ensure that the guide plate 6 slides smoothly. The support beam 3 has a movable groove 603, which is connected to the second guide groove 602. A guide rod 608 is fixed in the movable groove 603 and a movable block 606 is slidably connected to it. A first motor 609 is fixed inside the support beam 3 by a motor bracket. The preferred model is a three-phase asynchronous motor, servo motor, or stepper motor of Y90L-4. The output shaft of the first motor 609 is connected to a first threaded rod 610 through a coupling. The first threaded rod 610 passes through the movable slot 603 and is threadedly connected to the movable block 606. The guide rod 608 passes through the movable block 606 and guides the movable block 606. The guide plate 6 has a first guide block 604 and a second guide block 605 welded to its edge. The first guide block 604 is close to the top of the guide plate 6 and is slidably connected to the inside of the first guide groove 601. The second guide block 605 is close to the bottom of the guide plate 6 and is slidably connected to the inside of the second guide groove 602. The second guide block 605 is welded with a fixed shaft 607, which is rotatably connected to the inside of the movable block 606 through a bearing, so as to realize the adaptive adjustment of the angle of the guide plate 6 as the movable block 606 moves.

[0036] In use, the first motor 609 is started to drive the first threaded rod 610 to rotate, thereby driving the movable block 606 to rise and fall. The rise and fall of the movable block 606 drives the fixed shaft 607 and the second guide block 605 to slide, thereby driving the guide plate 6 to slide. The first guide block 604 is guided by the first guide groove 601, thereby causing the guide plate 6 to slide and rotate to adjust the position of the guide plate 6.

[0037] Sliding mechanism 7 and lifting mechanism 8: The top of the base plate 5 is provided with a sliding structure 7, which is used to drive the lifting mechanism 8 to move along the longitudinal (tunnel width direction) and transverse (tunnel length direction) of the base plate 5: A lifting mechanism 8 is fixed to the top of the movable plate 703 of the sliding structure 7, which is used to adjust the height of the clamping component 9. Specifically, the sliding structure 7 includes 2-3 slide rails 701 located on the top of the base plate 5, preferably of model HGH25. The slide rails 701 are fixed along the length of the base plate 5, and the sliding end of the slide rails 701 is fixed with a sliding plate 702 by bolts. Two fixed sleeves 706 are welded to the top of the sliding plate 702 along the width direction of the base plate 5. The two fixed sleeves 706 are located at the edge of the sliding plate 702 and are slidably connected to the movable plate 703. The top of the sliding plate 702 is provided with a positioning groove 705, which is preferably a T-shaped groove. The bottom of the movable plate 703 is welded with a T-shaped sliding block, which is adapted to the positioning groove 705 and is used to guide the movable plate 703 to slide laterally. A groove 707 is provided on the side of the fixed sleeve 706 near the movable plate 703. A slider 708 is slidably connected in the groove 707. The slider 708 is welded and fixed to the fixed plate 704 at the top of the movable plate 703. The end of the fixed sleeve 706 is fixed with a second motor 709 via a motor bracket. The preferred model is a three-phase asynchronous motor, servo motor, or stepper motor of model Y100L-4. The output shaft of the second motor 709 is connected to a second threaded rod 710 via a coupling. The second threaded rod 710 passes through the slider 708 and is threadedly connected to the slider 708, driving the movable plate 703 to move laterally.

[0038] In use, the second motor 709 starts and drives the second threaded rod 710 to rotate, which in turn drives the slider 708 to rotate. This causes the movable plate fixing plates 704 and 703 and the lifting mechanism 8 to slide along the width direction of the base plate 5, thereby adjusting the position of the clamping member 9 to meet different usage requirements. The slide rail 701 can drive the sliding plate 702 and its connected clamping member 9 to slide along the length direction of the base plate 5 to further meet different position usage requirements.

[0039] Furthermore, the lifting mechanism 8 includes a support sleeve 801 fixed to the top of the movable plate 703, and a movable seat 802 is slidably connected inside the support sleeve 801. The top of the movable seat 802 is fixed with a hydraulic rod 803 by bolts. The preferred model is a CD250 hydraulic push rod. The clamping part 9 is connected to the output end of the hydraulic rod 803. A top plate 804 is welded to the top of the support sleeve 801, and the hydraulic rod 803 passes through the top plate 804. The top plate 804 protects the hydraulic rod 803. Two fixing shells 805 are welded to the side of the support sleeve 801. A third motor 806 is fixed to the top of the fixing shell 805 by a motor bracket. Preferably, it is a three-phase asynchronous motor, stepper motor or servo motor of model Y112M-4. The output shaft of the third motor 806 is connected to a third threaded rod 807 via a coupling. The third threaded rod 807 is threadedly connected to a connecting block 808, which is slidably connected inside the fixed housing 805. The connecting block 808 and the movable seat 802 are welded and fixed together via a connecting plate 809. The fixed housing 805 and the support sleeve 801 are provided with grooves for the sliding of the connecting block 808 and the connecting plate 809, ensuring that the movable seat 802 can be raised and lowered stably.

[0040] When in use, the third motor 806 starts and drives the third threaded rod 807 to rotate, which in turn drives the connecting block 808 to rise and fall, thereby driving the connecting plate 809 and the movable seat 802 to rise and fall, which in turn drives the hydraulic rod 803 to rise and fall, and finally drives the clamping part 9 to rise and fall. The hydraulic rod 803 can extend and retract to further adjust the height of the clamping part 9.

[0041] The hydraulic rod 803 of the lifting mechanism 8 has a clamping component 9 fixed at its output end, which is used to assist in clamping the fiberglass reinforcement 2 or the shotcrete spray gun to achieve precise construction. Specifically, the clamping component 9 includes a fixed base 901, on which a clamping jaw 902 is connected by a pin. The inner side of the clamping jaw 902 is provided with an anti-slip rubber pad to enhance clamping stability. The clamping jaw 902 is preferably an existing hydraulic clamping jaw.

[0042] A reducer 903 and a fourth motor 904 are fixed to the fixed base 901 by bolts. The fourth motor 904 is preferably a stepper motor or a servo motor. The speed and angle are controlled by existing methods. The output shaft of the fourth motor 904 is connected to the input shaft of the reducer 903 by a coupling. The output shaft of the reducer 903 is connected to the gripper 902 to control the rotation of the gripper 902. After the gripper 902 clamps the shotcrete spray gun, the concrete spraying angle can be adjusted by controlling the rotation of the gripper 902. A protective shell 905 is welded onto the fixed base 901 to cover the reducer 903 and the fourth motor 904, preventing dust and gravel from damaging the equipment during construction.

[0043] In the above scheme, the glass fiber reinforcement 2 includes hollow reinforcement 201 and solid reinforcement 202, both of which are made of high-strength glass fiber reinforced polymer (GFRP). The hollow reinforcement 201 has a through grouting channel inside for grouting operations. The solid reinforcement 202 is a solid structure used to enhance the bearing capacity of the surrounding rock. The hollow reinforcement 201 and solid reinforcement 202 are alternately arranged in the circumferential direction, and the spacing between two adjacent glass fiber reinforcements 2 is 40-50cm, realizing the integrated function of "reinforcement + grouting".

[0044] When concrete spraying is required, the spray gun is held by the gripper 902 and then moved laterally to a position close to the working face via the sliding structure 7. The existing concrete spraying method is then used to start the spraying. During the spraying process, the gripper 902 rotates up and down to adjust the spraying angle, and the lifting mechanism 8 raises and lowers to adjust the spraying height. When the spraying mechanism 8 moves longitudinally along the base plate 5 and encounters the glass fiber reinforcement 2, it moves the gripper 902 down to the lowest point, then moves longitudinally again, and then raises and lowers again. This process is repeated to complete the concrete spraying.

[0045] Furthermore, to facilitate concrete spraying, the auxiliary equipment can be slid away from the working face to reduce the impact of the glass fiber reinforcement 2 on the concrete spraying process, so that the gripper 902 will not be affected by the glass fiber reinforcement 2 when it moves.

[0046] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for tunnel excavation in weak surrounding rock, characterized by: Includes the following steps: S1. Construct advanced small guide pipes at the designed location, and divide the lower step (101) and upper step (102). S2, Multiple fiberglass reinforcement bars (2) are installed in the upper step (102) area; S3. The unsupported area at and near the working face is sealed with shotcrete to form a grout-stopping wall; S4. Grouting is performed using glass fiber reinforcement (2); S5. After grouting is completed and reaches the design strength, excavation of the upper step (102) begins; S6. After the excavation is completed, the initial spraying is carried out, followed by the construction of the steel frame and anchor bolts. After the construction of the steel frame and anchor bolts is completed, the re-spraying is carried out. S7. Excavation and support of the lower step, completing one cycle of operation; S8. Repeat S1-S7 until the entire tunnel construction is completed.

2. The method for tunnel excavation in weak surrounding rock according to claim 1, characterized in that: In S2, auxiliary equipment is first set up, and the construction position of glass fiber reinforcement (2) is located by the auxiliary equipment. The construction workers and the working face are isolated by auxiliary equipment. When the working face collapses due to the construction of glass fiber reinforcement (2), the auxiliary equipment is used to isolate the workers to ensure their safety. A space is reserved between the auxiliary equipment and the working face to allow space for concrete spraying in S3.

3. The method for tunnel excavation in weak surrounding rock according to claim 1, characterized in that: The glass fiber reinforcement (2) includes hollow reinforcement (201) and solid reinforcement (202), which are alternately arranged. The solid reinforcement (202) is used to increase the strength of the construction site, and the hollow reinforcement (201) is used for grouting.

4. The method for tunnel excavation in weak surrounding rock according to claim 1, characterized in that: In S4, the grouting construction sequence is from the outer ring of the working face to the inner ring.

5. An auxiliary device for the tunnel excavation method in weak surrounding rock as described in any one of claims 1-4, characterized in that: Includes a base plate (5), and a support beam (3) is provided on the top of the base plate (5). The shape of the support beam (3) is adapted to the tunnel. The base plate (5) is provided with an extension plate (501), and both the extension plate (501) and the base plate (5) are provided with rollers (502) for assisting in the movement of the equipment; The inner side of the support beam (3) is provided with a protective plate (4), and the protective plate (4) is provided with several guide holes (401). The guide hole (401) is used to guide the construction of the glass fiber reinforcement (2).

6. The auxiliary equipment for a tunnel excavation method in weak surrounding rock according to claim 5, characterized in that: The base plate (5) is provided with a sliding structure (7), and the sliding structure (7) is provided with a lifting mechanism (8). The sliding structure (7) is used to drive the lifting mechanism (8) to move vertically and horizontally along the base plate (5); The lifting mechanism (8) is equipped with a clamping component (9) at the top, which is used to assist in clamping the glass fiber reinforcement (2) or the sprayed concrete gun.

7. The auxiliary equipment for a tunnel excavation method in weak surrounding rock according to claim 6, characterized in that: The sliding structure (7) includes several slide rails (701) located on the top of the base plate (5), and the slide rails (701) are arranged along the length of the base plate (5); The sliding end of the slide rail (701) is provided with a sliding plate (702), and the top of the sliding plate (702) is provided with two fixing sleeves (706) along the width direction of the base plate (5). The two fixing sleeves (706) are located at the edge of the sliding plate (702). A movable plate (703) is slidably connected between the two fixed sleeves (706), and a fixed plate (704) is provided on the top side of the movable plate (703) near the fixed sleeve (706). The top of the sliding plate (702) is provided with a positioning groove (705), and the bottom of the movable plate (703) is provided with a T-shaped sliding block that is slidably connected to the inside of the positioning groove (705); the T-shaped sliding block is adapted to the positioning groove (705); The fixed sleeve (706) has a groove (707) on the side near the movable plate (703), and a slider (708) is slidably connected in the groove (707). The slider (708) is fixedly connected to the fixed plate (704). The end of the slide (707) is provided with a second motor (709), and the output shaft of the second motor (709) is provided with a second threaded rod (710). The second threaded rod (710) passes through the slider (708) and is threadedly connected to the slider (708).

8. The auxiliary equipment for a tunnel excavation method in weak surrounding rock according to claim 7, characterized in that: The lifting mechanism (8) includes a support sleeve (801) fixed to the top of the movable plate (703), and a movable seat (802) is slidably connected inside the support sleeve (801). The top of the movable seat (802) is provided with a hydraulic rod (803); the clamping member (9) is connected to the output end of the hydraulic rod (803); The top of the support sleeve (801) is provided with a top plate (804), and the hydraulic rod (803) passes through the top plate (804). The side of the support sleeve (801) is provided with several fixing shells (805). The top of the fixed housing (805) is provided with a third motor (806), and the output shaft of the third motor (806) is provided with a third threaded rod (807). The third threaded rod (807) is threadedly connected to a connecting block (808), which is slidably connected to the inside of the fixed shell (805); The connecting block (808) and the movable seat (802) are connected by a connecting plate (809); The fixed housing (805) and the support sleeve (801) are provided with grooves for sliding of the connecting block (808) and the connecting plate (809).

9. The auxiliary equipment for a tunnel excavation method in weak surrounding rock according to claim 8, characterized in that: The clamping member (9) includes a fixed base (901), and the fixed base (901) is provided with a gripper (902); The fixed base (901) is equipped with a reducer (903) and a fourth motor (904). The output shaft of the fourth motor (904) is connected to the input shaft of the reducer (903), and the output shaft of the reducer (903) is connected to the gripper (902). The mounting base (901) is provided with a protective shell (905), which covers the reducer (903) and the fourth motor (904).

10. The auxiliary equipment for a tunnel excavation method in weak surrounding rock according to claim 5, characterized in that: The inner side of the support beam (3) is provided with a guide plate (6) located below the protective plate (4); The guide plate (6) slides between the first position and the second position. When it slides to the first position, the guide plate (6) is tilted and positioned below the protective plate (4). At this time, the edge of the guide plate (6) is close to the edge plate of the support beam (3) to block the lower end of the protective plate (4) on the side close to the working face. When it slides to the second position, the guide plate (6) slides to the bottom of the support beam (3) and is close to or in a vertical state. The connection structure between the support beam (3) and the guide plate (6) includes a first guide groove (601) and a second guide groove (602) located inside the support beam (3). The second guide groove (602) is a vertical groove and is close to the edge of the support beam (3). The first guide groove (601) and the second guide groove (602) are connected and smoothly joined; The support beam (3) is provided with a movable groove (603), which is connected to the second guide groove (602); The support beam (3) is equipped with a first motor (609), and the output shaft of the first motor (609) is equipped with a first threaded rod (610), which passes through the movable groove (603). The movable groove (603) is provided with a guide rod (608) and a movable block (606) is slidably connected thereto. The guide rod (608) and the first threaded rod (610) both pass through the movable block (606). The movable block (606) is threadedly connected to the first threaded rod (610) and slidably connected to the guide rod (608). The guide plate (6) has a first guide block (604) and a second guide block (605) on its edge; The first guide block (604) is close to the top of the guide plate (6) and is slidably connected to the inside of the first guide groove (601); the second guide block (605) is close to the bottom of the guide plate (6) and is slidably connected to the inside of the second guide groove (602). The second guide block (605) is provided with a fixed shaft (607), which is rotatably connected to the interior of the movable block (606).

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