Asymmetric minimum clear distance tunnel support and construction method

Abstract

The invention relates to the technical field of underground engineering, and particularly discloses an asymmetric minimum clear distance tunnel support and construction method.The asymmetric minimum clear distance tunnel support comprises a small-section tunnel and a large-section tunnel, the small-section tunnel is provided with a plurality of sets of first anchor rods and a plurality of sets of second anchor rods, and the first anchor rods face the radial direction of the small-section tunnel; the second anchor rods face the large-section tunnel, parts of the second anchor rods are located above the large-section tunnel, a plurality of third anchor rods are arranged on the large-section tunnel, and the third anchor rods face the radial direction of the large-section tunnel; a supporting mechanism for supporting is arranged in the large-section tunnel; the technical problems that when a large-section tunnel is excavated, due to the bias effect, the large-section tunnel is prone to being affected by asymmetric loads, and consequently stress in the large-section tunnel is unstable and serious and even collapses occur are solved.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering, and specifically discloses an asymmetric extremely small clear distance tunnel support and a construction method. Background Art

[0002] When building tunnels, due to the limitations of terrain and design conditions, traditional tunnels cannot meet the needs, so asymmetric small clearance tunnels came into being. During the construction of asymmetric small clearance tunnels, the distance between the two tunnels is small, the interaction effect is large, and the heading areas of the two tunnels are different, the bias pressure is serious, resulting in complex mechanical behavior during construction, uneven deformation and stress distribution, making excavation more difficult.

[0003] When excavating an asymmetric small clearance tunnel, the smaller cross-section tunnel is excavated first, and then the larger cross-section tunnel is excavated. This excavation method can effectively ensure the stability of the surrounding rock. Since the bias effect is more obvious in the construction of an asymmetric small cross-section tunnel, different excavation methods need to be used according to the specific situation to control the bias effect. When excavating existing asymmetric small clearance tunnels, due to the bias effect, when excavating a large cross-section tunnel, the large cross-section tunnel is easily affected by the asymmetric load, resulting in unstable force in the large cross-section tunnel, and even collapse in severe cases. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide an asymmetric and extremely small clearance tunnel support and construction method to solve the technical problem that when excavating a large-section tunnel, due to the existence of a bias effect, the large-section tunnel is easily affected by asymmetric loads, resulting in unstable force in the large-section tunnel, and even collapse in severe cases.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an asymmetric tunnel support structure with extremely small clearance, comprising a small-section tunnel and a large-section tunnel, the small-section tunnel is provided with a plurality of first anchor rods and a plurality of second anchor rods, the first anchor rods face the radial direction of the small-section tunnel, the plurality of second anchor rods face the large-section tunnel, the second anchor rods are partially located above the large-section tunnel, the large-section tunnel is provided with a plurality of third anchor rods, the third anchor rods face the radial direction of the large-section tunnel; a support mechanism for supporting is provided in the large-section tunnel. When excavating the tunnel, the small-section tunnel is reinforced by the first anchor rod, and the large-section tunnel is reinforced by the third anchor rod. Since the excavation progress of the small-section tunnel is always faster than that of the large-section tunnel, the second anchor rod can strengthen the strength of the rock mass above the large-section tunnel, thereby ensuring the stability of the rock mass above the large-section tunnel when the large-section tunnel is excavated, thereby preventing the large-section tunnel from collapsing when it is excavated.

[0006] Furthermore, the support mechanism includes two groups of support components, the support components include a fixed frame, and both ends of the fixed frame are provided with a first fixed seat and a connecting column, the first fixed seat is located below the fixed frame, and the connecting column is located above the fixed frame; a support frame is provided between the two groups of connecting columns, the support frame is in contact with the top of the large-section tunnel, and a vibration reduction component is provided between the support frame and the fixed frame. The support mechanism can fix the large-section tunnel that has been excavated but has not undergone a secondary lining section, thereby supporting the large-section tunnel and preventing the large-section tunnel from collapsing. At the same time, the support mechanism can move with the excavation of the large-section tunnel, and can ensure that the large-section tunnel can always be supported, thereby ensuring the structural strength of the large-section tunnel and preventing the large-section tunnel from collapsing.

[0007] Furthermore, the vibration reduction assembly includes a movable frame, the movable frame is slidably mounted on the support frame, the movable frame is fitted with the top of the large-section tunnel, and three groups of movable columns are arranged on the movable frame, one group of movable columns is located at the center of the movable frame, and the other two groups of movable columns are respectively located on both sides of the movable frame; the movable columns located on both sides of the movable frame are respectively mounted on two groups of connecting columns, and the two groups of connecting columns are mounted with a first spring, and the two ends of the first spring are respectively in contact with the movable column and the fixed frame; the connecting column located at the center of the movable frame is provided with a first matching column, and the center of the movable frame is provided with a second matching column, the first matching column is installed in the second matching column, and the first matching column is mounted with a second spring, and the two ends of the second spring are respectively in contact with the movable column and the second matching column. The vibration reduction assembly can reduce the vibration of the top of the large-section tunnel, thereby reducing the impact on the excavated area when the large-section tunnel is excavated, thereby ensuring the structural strength of the large-section tunnel.

[0008] Further, the two groups of the first fixed seats on the same side are both provided with a support assembly, the support assembly includes two groups of movable plates, a second hydraulic cylinder is provided between the two groups of movable plates, and limiting columns are provided on both sides of the movable plates, wherein the two groups of limiting columns on one group of movable plates are respectively installed in the two groups of the second fixed seats, and the second fixed seats are provided on both sides of the other group of movable plates, and the corresponding two groups of limiting columns on the movable plates are respectively installed in the two groups of the second fixed seats; the second fixed seat is provided with a ground plug, the ground plug is clamped in the large-section tunnel, the second fixed seat is provided with a movable block, the ground plug is provided with a sliding groove, the movable block is slidably clamped in the sliding groove, and the ground plug is fixedly connected to the second fixed seat by bolts. The support assembly can fix the support mechanism in the large-section tunnel, and can also adjust the height of the support mechanism, so as to ensure that the support mechanism can be applied to large-section tunnels of different heights, thereby improving the adaptability of the support mechanism.

[0009] Furthermore, a third hydraulic cylinder is provided between the two groups of the second fixed seats on the same side, a group of ground plugs and two groups of slide rails are provided between the two groups of ground plugs, one end of the two groups of slide rails are respectively fixedly connected to two groups of the ground plugs, and the other end is fixedly connected to the remaining group of ground plugs; a fixed platform is provided on the ground plug, a connecting groove is provided on the movable block, the connecting groove is aligned with the slide rail, and a slider is provided on the second fixed seat, the slider is aligned with the slide rail. Through the two groups of slide rails and the first ground plug, it can be ensured that the support mechanism can move to the specified position, so that the support mechanism can move with the progress of the large-section tunnel excavation, thereby ensuring that it always plays a supporting role.

[0010] Furthermore, a plurality of groups of the first fixing seats are each provided with a fixing block, the fixing block is provided with a first matching block, the first matching block is fitted with a second matching block, the second matching block is in contact with the inner wall of the large-section tunnel, and a first hydraulic cylinder is provided between the first matching block and the second matching block. The side wall of the large-section tunnel is supported by the second matching block to enhance the structural strength of the large-section tunnel, thereby preventing the large-section tunnel from collapsing.

[0011] Furthermore, several groups of connection components are arranged between the two groups of the fixing frames, and the connection components include a connection sleeve, which is fixedly connected to one group of the fixing frames, and a connection block is arranged on the other group of the fixing frames, and the connection block is slidably mounted in the connection sleeve, and pin holes are provided on the connection sleeve and the connection block, and fixing pins are inserted into the two groups of pin holes; a connection frame is arranged on the connection sleeve, and the connection frame contacts the connection sleeve, and several groups of fixing pins are fixedly connected to the connection frame. The connection component fixes the two groups of fixing frames so that the two groups of support components can be connected, so that when the support mechanism supports the large-section tunnel, the structural strength of the support mechanism is increased, thereby improving the structural strength of the large-section tunnel.

[0012] An asymmetric minimum clearance tunnel construction method comprises the following steps: S1: First, excavate a pilot tunnel. After the pilot tunnel is excavated for a certain distance, start excavating a small-section tunnel. The excavation distance between the pilot tunnel and the small-section tunnel is 40m. While excavating the small-section tunnel, insert several groups of first anchor rods into the rock mass along the radial direction of the small-section tunnel, and insert several groups of second anchor rods in the direction of the large-section tunnel.

[0013] S2: After the small-section tunnel is excavated for a certain distance, the large-section tunnel is started. The excavation distance between the small-section tunnel and the large-section tunnel is 60m. While excavating the large-section tunnel, the third anchor is inserted into the rock mass along the radial direction of the large-section tunnel. At the same time, it is necessary to prevent the third anchor from crossing the second anchor. When excavating the large-section tunnel, it is necessary to use a support mechanism in the excavation area to provide initial support for the large-section tunnel, and then carry out secondary lining. Keeping the distance between the initial support and the secondary lining at 5m can most effectively ensure the structural strength of the large-section tunnel.

[0014] S3: When initially supporting a large-section tunnel, the staff first moves the support mechanism to the place where the large-section tunnel needs to be initially supported, and then uses the ground plug to cooperate with the second hydraulic cylinder to fix the support mechanism and support the large-section tunnel at the same time. Then, the first hydraulic cylinder drives the second matching block to move so that the second matching block contacts the side wall of the large-section tunnel to support the side wall of the large-section tunnel.

[0015] S4: As the large-section tunnel is continuously excavated, the support mechanism needs to be moved accordingly. When moving the support mechanism, the staff first removes the bolts between the two sets of second fixing seats and the two sets of ground plugs at the rear, and then moves the connecting frame to separate the fixing pins from the pin holes, and then simultaneously starts the two sets of third hydraulic cylinders. The two sets of third hydraulic cylinders drive a set of support components at the rear to move until the third hydraulic cylinders are fully retracted, and then the ground plugs are fixed to the corresponding movable blocks by bolts. At this time, the distance between the two sets of support components is relatively close.

[0016] S5: Then the staff separates the slide rail near the rear from the ground plug at the center, moves the slide rail and the ground plug to the front of the support mechanism, and fixes the slide rail on one of the ground plugs. Then the staff removes the bolts between the two groups of second fixing seats and the two groups of ground plugs in the front, and then drives the support assembly in the front to move forward through the third hydraulic cylinder until the third hydraulic cylinder is fully extended, and then fixes the second fixing seat to the corresponding ground plug through bolts. Finally, the staff moves the connecting frame so that the fixing pin is clamped in the pin hole to complete the forward movement of the support mechanism.

[0017] The working principle and beneficial effects of this solution are: During construction, a pilot tunnel is first excavated, and then a small-section tunnel is excavated. When excavating the small-section tunnel, several groups of first anchor rods and several groups of second anchor rods are inserted from the small-section tunnel into the rock body. The first anchor rods are used to strengthen the structural strength of the small-section tunnel, and the second anchor rods are used to strengthen the structural strength above the large-section tunnel to ensure that no collapse occurs when excavating the large-section tunnel. Then the workers excavate the large-section tunnel. During excavation, the third anchor rod is inserted from the large-section tunnel into the rock body to enhance the structural strength of the large-section tunnel. At the same time, support is provided in the large-section tunnel through a supporting mechanism, thereby enhancing the structural strength of the large-section tunnel.

[0018] When the supporting mechanism supports the large-section tunnel, it can move with the excavation progress of the large-section tunnel, and the moving steps are simple, without the need for workers to spend too much time and physical strength, so that the supporting mechanism can be quickly moved to the designated position; at the same time, the vibration reduction component can offset the vibration generated by the blasting and play a role in vibration reduction, thereby alleviating the pressure exerted by the blasting on the large-section tunnel, and by reducing the force on the initial support section of the large-section tunnel, it is ensured that the supporting mechanism can support the large-section tunnel and prevent the large-section tunnel from collapsing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of an embodiment; Figure 2 Schematic diagram of the internal structure of the rock mass in the embodiment; Figure 3 It is a schematic cross-sectional view of an embodiment; Figure 4 It is a structural schematic diagram of the supporting mechanism of the embodiment; Figure 5 An exploded view of the support mechanism of the embodiment; Figure 6 for Figure 5 The enlarged schematic diagram of point A in the middle; Figure 7 for Figure 5 The enlarged schematic diagram of point B in the middle; Figure 8 is a cross-sectional view of the support mechanism in the embodiment; Fig. 9 Schematic diagram of the structure of the fixing assembly and the vibration reduction assembly in the embodiment.

[0020] The markings in the attached figure are as follows: rock mass 101, small cross-section tunnel 102, large cross-section tunnel 103, medium rock wall 104, pilot tunnel 105; A first anchor rod 201, a second anchor rod 202, and a third anchor rod 203; A fixing frame 301, a first fixing seat 302, a fixing block 303, a first matching block 304, a first hydraulic cylinder 305, a second matching block 306, a connecting column 307, and a supporting frame 308; The movable plate 401, the limiting column 402, the limiting groove 403, and the second hydraulic cylinder 404; A second fixed seat 501, a movable block 502, a sliding slot 503, a ground plug 504, and a fixed slot 505; Sliding block 601, connecting groove 602, fixing platform 603, sliding rail 604, third hydraulic cylinder 605; A movable frame 701, a movable column 702, a first spring 703, a first matching column 704, a second spring 705, and a second matching column 706; Connecting sleeve 801 , connecting block 802 , pin hole 803 , fixing pin 804 , connecting frame 805 . DETAILED DESCRIPTION

[0021] The following is further described in detail through specific implementation methods: Example

[0022] like Figures 1 to 9 As shown, an asymmetric extremely small clear distance tunnel support structure is disclosed, including a rock mass 101, on which a pilot tunnel 105, a small cross-section tunnel 102 and a large cross-section tunnel 103 are opened, the small cross-section tunnel 102 and the large cross-section tunnel 103 are respectively located on both sides of the pilot tunnel 105, a middle rock wall 104 is arranged between the large cross-section tunnel 103 and the small cross-section tunnel 102, and the middle rock wall 104 is located in the pilot tunnel 105.

[0023] A plurality of groups of first anchor rods 201 are arranged on the small-section tunnel 102, and the plurality of groups of first anchor rods 201 are all oriented in the radial direction of the small-section tunnel 102; a plurality of groups of third anchor rods 203 are arranged on the large-section tunnel 103, and the plurality of groups of third anchor rods 203 are all oriented in the radial direction of the large-section tunnel 103; a plurality of groups of second anchor rods 202 are arranged on the small-section tunnel 102, and the plurality of groups of second anchor rods 202 are all oriented in the direction of the large-section tunnel 103, and a plurality of groups of second anchor rods 202 are located above the large-section tunnel 103, such as Figure 2 and Figure 3 shown.

[0024] A support mechanism is provided in the large-section tunnel 103, and the support mechanism includes two groups of support components, the support components include a fixing frame 301, and first fixing seats 302 and connecting columns 307 are provided at both ends of the fixing frame 301. The two groups of first fixing seats 302 are located below the fixing frame 301, and the two groups of connecting columns 307 are located above the fixing frame 301. A support frame 308 is provided between the two groups of connecting columns 307, and the support frame 308 is in contact with the top of the large-section tunnel 103. The curvature of the support frame 308 is the same as the curvature of the top of the large-section tunnel 103. The two groups of first fixing seats 302 are provided with A fixed block 303 is arranged, the fixed block 303 is perpendicular to the first fixed seat 302, a first matching block 304 is arranged on the fixed block 303, a second matching block 306 is sleeved on the first matching block 304, the first matching block 304 is movably connected with the second matching block 306, a first hydraulic cylinder 305 is arranged between the first matching block 304 and the second matching block 306, a fixed end of the first hydraulic cylinder 305 is fixedly connected to the first matching block 304 by bolts, and a telescopic end is fixedly connected to the second matching block 306, and the second matching block 306 contacts the inner wall of the large-section tunnel 103, such as Figure 1 and Figure 4 shown.

[0025] The two groups of first fixed seats 302 on the same side are provided with fixed components, which include two groups of movable plates 401, both ends of the movable plates 401 are provided with limit posts 402, and the two groups of first fixed seats 302 are provided with limit slots 403, and the two groups of limit posts 402 on one group of movable plates 401 are respectively installed in the two groups of limit slots 403, and a second hydraulic cylinder 404 is provided between the two groups of movable plates 401, and the fixed end of the second hydraulic cylinder 404 is fixedly connected to the movable plate 401 located below by bolts, and the telescopic end is fixedly connected to On the upper movable plate 401, second fixing seats 501 are arranged on both sides of the lower movable plate 401, and limiting grooves 403 are arranged on the second fixing seats 501. Two groups of limiting columns 402 located on the lower movable plate 401 are respectively installed in the limiting grooves 403 on the two groups of second fixing seats 501. Removable ground plugs 504 are arranged under the four groups of second fixing seats 501. Several groups of fixing grooves 505 are opened on the rock mass 101 of the large-section tunnel 103. The four groups of ground plugs 504 are all clamped in the corresponding fixing grooves 505. Figure 5 and Figure 7 shown.

[0026] A movable block 502 is provided on the second fixed seat 501, a sliding groove 503 is provided on the ground plug 504, the movable block 502 is slidably mounted in the fixed groove 505, the ground plug 504 is fixedly connected to the second fixed seat 501 by bolts, a slider 601 is provided on the movable block 502, a fixed platform 603 is provided on the ground plug 504, the fixed platform 603 is located in the sliding groove 503, the slider 601 is in contact with the fixed platform 603, two groups of slide rails 604 are provided between the two groups of ground plugs 504, a connecting groove 602 is provided on the movable block 502, the connecting groove 602 is aligned with the slide rail 604, a ground plug 504 is provided between the two groups of slide rails 604, both ends of the slide rail 604 are fixedly connected to the ground plug 504, a third hydraulic cylinder 605 is provided between two adjacent groups of second fixed seats 501, the fixed end of the third hydraulic cylinder 605 is fixedly connected to one group of second connecting seats, and the other end is fixedly connected to the other group of second connecting seats, such as Figure 5 and Figure 6 shown.

[0027] The support frame 308 is provided with a vibration reduction assembly, which includes a movable frame 701, which is mounted on the support frame 308, and the cross section of the movable frame 701 is arc-shaped, one side of the movable frame 701 is in contact with the top of the large-section tunnel 103, and the curvature of the movable frame 701 is the same as the curvature of the top of the large-section tunnel 103. The movable frame 701 is provided with three groups of movable columns 702, two groups of movable columns 702 are respectively located at both ends of the movable frame 701, and the remaining group of movable columns 702 is located at the center of the movable frame 701. The movable columns 702 located at both ends are respectively mounted on two groups of connecting columns 307, and are slidably connected to the connecting columns 307. The movable columns 702 located at both ends are respectively mounted on two groups of connecting columns 307, and are slidably connected to the connecting columns 307. 2 and the fixing frame 301 are provided with a first spring 703, both ends of the first spring 703 are in contact with the movable column 702 and the fixing frame 301 respectively, the connecting column 307 is inserted into the corresponding first spring 703, the movable column 702 at the center is provided with a first matching column 704, the center of the fixing frame 301 is provided with a second matching column 706, the first matching column 704 is inserted into the second matching column 706, a second spring 705 is provided between the second matching column 706 and the corresponding movable column 702, both ends of the second spring 705 are in contact with the movable column 702 and the second matching column 706 respectively, the first matching column 704 is inserted into the second spring 705, as shown in FIG. Fig. 9 shown.

[0028] Several groups of connection components are arranged between the two groups of fixing frames 301, and the connection components include a connection sleeve 801, the connection sleeve 801 is fixedly connected to one group of fixing frames 301, and a connection block 802 is arranged on the other group of fixing frames 301, and the connection block 802 is slidably mounted in the connection sleeve 801, and pin holes 803 are provided on the connection block 802 and the connection sleeve 801, and the two groups of pin holes 803 are aligned, and fixing pins 804 are inserted into the pin holes 803, and the fixing pins 804 fix the connection sleeve 801 and the connection block 802. Several groups of fixing pins 804 are fixedly connected to the connection frame 805, and the connection frame 805 is located above the connection sleeve 801 and contacts with the connection sleeve 801, such as Figure 8 shown.

[0029] The asymmetric minimum clearance tunnel construction method comprises the following steps: S1: First, excavate the pilot tunnel 105. When the pilot tunnel 105 is excavated for a certain distance, start excavating the small-section tunnel 102. The excavation distance between the pilot tunnel 105 and the small-section tunnel 102 is between 15m and 50m. The excavation distance is determined by the strength of the rock mass 101. The lower the strength of the rock mass 101, the longer the excavation distance between the pilot tunnel 105 and the small-section tunnel 102; the higher the strength of the rock mass 101, the shorter the excavation distance between the pilot tunnel 105 and the small-section tunnel 102. Short; after the small-section tunnel 102 is excavated, several groups of first anchor rods 201 are first arranged radially along the small-section tunnel 102, and the first anchor rods 201 are used to enhance the strength of the small-section tunnel 102. Then, several groups of second anchor rods 202 are inserted from the small-section tunnel 102 toward the direction of the large-section tunnel 103. Part of the second anchor rods 202 are located above the large-section tunnel 103, and the second anchor rods 202 are used to enhance the structural strength of the rock mass 101 above the large-section tunnel 103.

[0030] S2: After the small-section tunnel 102 is excavated for a certain distance, the large-section tunnel 103 is started to be excavated. The excavation distance between the small-section tunnel 102 and the large-section tunnel 103 is between 25-80m, and the excavation distance is determined according to the strength of the rock mass 101. When excavating the large-section tunnel 103, the anchor rods above the large-section tunnel 103 can strengthen the structural strength of the rock mass 101 and reduce the influence of the bias effect on the large-section tunnel 103. At the same time, when blasting the large-section tunnel 103, the strength of the rock mass 101 above the large-section tunnel 103 can also be strengthened, thereby improving the stability of the structure of the large-section tunnel 103.

[0031] S3: When excavating the large-section tunnel 103, it is necessary to drive the third anchor 203 from the large-section tunnel 103 into the rock mass 101 to enhance the structural strength of the large-section tunnel 103. At the same time, it is necessary to prevent the third anchor 203 from crossing the second anchor 202. It is necessary to use a support mechanism in the excavation area to provide initial support for the large-section tunnel 103, and then determine the time for secondary lining based on the stability of the rock mass 101. The distance between the initial support and the secondary lining is usually kept at 5-20m, which is the most suitable. Due to the bias effect of the large-section tunnel 103, keeping the distance between the initial support and the secondary lining at 5m can most effectively ensure the structural strength of the large-section tunnel 103 and prevent the large-section tunnel 103 from collapsing.

[0032] S4: When initially supporting the large-section tunnel 103, the staff first moves the supporting mechanism into the large-section tunnel 103, and then the ground plug 504 is partially inserted into the large-section tunnel 103 by the gravity of the supporting mechanism itself, and then the two groups of second hydraulic cylinders 404 are started at the same time, and the telescopic ends of the two groups of second hydraulic cylinders 404 are extended, and the telescopic ends first drive the fixed frame 301, the support frame 308 and the movable frame 701 to move upward until the support frame 308 and the movable frame 701 contact the inner wall of the large-section tunnel 103. At this time, the support frame 308 and the fixed frame 301 remain different, and the second hydraulic cylinder 404 continues to extend. At this time, the second hydraulic cylinder 404 drives the ground plug 504 to move downward until the ground plug 504 is completely inserted into the large-section tunnel 103. At this time, the supporting mechanism supports the large-section tunnel 103, which can increase the structural strength of the large-section tunnel 103 and prevent the large-section tunnel 103 from collapsing due to insufficient strength.

[0033] S5: Then, several groups of first hydraulic cylinders 305 are started simultaneously, and several groups of first hydraulic cylinders 305 drive the second matching blocks 306 to move, and the second matching blocks 306 slide on the first matching blocks 304 until the second matching blocks 306 contact the side wall of the large-section tunnel 103. At this time, the second matching blocks 306 support the side wall of the large-section tunnel 103, thereby increasing the structural strength of the large-section tunnel 103.

[0034] S6: When the large-section tunnel 103 is excavated, the support mechanism will continue to move forward with the progress of the excavation of the large-section tunnel 103. When the support mechanism moves forward, the staff first removes the bolts between the two rear groups of second fixed seats 501 and the two groups of ground plugs 504 to release the fixed connection between the ground plugs 504 and the fixed seats. Then the staff moves the connecting frame 805, and the connecting frame 805 drives several groups of fixed movements until the fixing pin 804 is separated from the pin hole 803. At this time, the fixing pin 804 is separated from the connecting sleeve 801 and the connecting block 802, and the connecting sleeve 801 is movably connected to the connecting block 802.

[0035] S7: Then start the two groups of third hydraulic cylinders 605 at the same time. The two groups of third hydraulic cylinders 605 shrink, driving a group of support components behind the displacement to move. When the support components move, the slider 601 first slides on the fixed platform 603. When the slider 601 slides in the slide rail 604, the slide rail 604 is located in the connecting groove 602, but the second fixed seat 501 does not contact the rock mass 101. At the same time, the limit column 402 slides in the limit groove 403, and the second fixed seat 501 approaches the movable plate 401 until the slider 601 completely slides into the slide rail 604, and then the slider 601 slides from the slide rail 604 to the adjacent ground plug 504. At this time, the third hydraulic cylinder 605 shrinks completely, and then the ground plug 504 is fixed to the corresponding movable block 502 by bolts. At this time, the distance between the two groups of support components is relatively close.

[0036] S8: The staff separates the slide rail 604 near the rear from the ground plug 504 at the center. At this time, the other end of the slide rail 604 is fixedly connected to one of the ground plugs 504. Then the staff moves the slide rail 604 and the ground plug 504 to the front of the ground plug 504 at the front. Then the staff inserts the ground plug 504 into the large-section tunnel 103. At this time, the ground plug 504 is located in front of the slide rail 604. Then the other end of the slide rail 604 is fixedly connected to the ground plug 504 at the rear. Then the staff connects the two front sets of second fixing seats 501 with the two sets of ground plugs. The bolts between the plugs 504 are removed, and the two groups of third hydraulic cylinders 605 are started at the same time. The two groups of third hydraulic cylinders 605 drive the support assembly located in the front to move forward until the third hydraulic cylinders 605 are fully extended, and then the second fixing seat 501 is fixedly connected to the corresponding ground plug 504 by bolts. Finally, the staff moves the connecting frame 805, and the connecting frame 805 drives the fixing pin 804 to move, so that the fixing pin 804 is clamped in the pin hole 803, and the connecting sleeve 801 is fixedly connected to the corresponding connecting block 802 to support the large-section tunnel 103.

[0037] When implementing: When the support mechanism supports the large-section tunnel 103 and the workers blast and excavate the large-section tunnel 103, the vibration generated by the blasting will be transmitted to the support frame 308 and the movable frame 701. At this time, the inner wall of the large-section tunnel 103 will apply a force to the support frame 308 and the movable frame 701. The support frame 308 supports the top of the large-section tunnel 103. The support frame 308 is always in contact with the inner wall of the large-section tunnel 103 to enhance the structural strength of the large-section tunnel 103. When the movable frame 701 is vibrated, When the movable column 702 moves downward, it drives the movable column 702 to move downward. The movable column 702 compresses the first spring 703 and the second spring 705. When the first spring 703 and the second spring 705 are shortened, the vibration transmitted by the movable frame 701 can be offset to play a role in vibration reduction. At this time, the vibration reduction component can reduce the vibration of the large-section tunnel 103 when blasting the large-section tunnel 103, thereby reducing the pressure on the large-section tunnel 103, thereby preventing the large-section tunnel 103 from collapsing.

[0038] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the present invention.

Claims

1. An asymmetric tunnel support structure with extremely small clearance, characterized in that: It comprises a small-section tunnel and a large-section tunnel, wherein the small-section tunnel is provided with a plurality of groups of first anchor rods and a plurality of groups of second anchor rods, wherein the first anchor rods face the radial direction of the small-section tunnel, and the plurality of groups of the second anchor rods all face the large-section tunnel, wherein the second anchor rods are partially located above the large-section tunnel, and the large-section tunnel is provided with a plurality of groups of third anchor rods, wherein the third anchor rods face the radial direction of the large-section tunnel; A supporting mechanism for supporting is arranged in the large-section tunnel.

2. The asymmetric tunnel support structure with extremely small clearance according to claim 1 is characterized in that: The support mechanism includes two groups of support components, and the support components include a fixing frame, and both ends of the fixing frame are provided with a first fixing seat and a connecting column, the first fixing seat is located below the fixing frame, and the connecting column is located above the fixing frame; A support frame is arranged between the two groups of connecting columns, the support frame is fitted with the top of the large-section tunnel, and a vibration reduction component is arranged between the support frame and the fixing frame.

3. The asymmetric tunnel support structure with extremely small clearance according to claim 2 is characterized in that: The vibration reduction assembly includes a movable frame, which is slidably mounted on the support frame, and the movable frame is in contact with the top of the large-section tunnel. Three groups of movable columns are arranged on the movable frame, one group of which is located at the center of the movable frame, and the other two groups of movable columns are respectively located on both sides of the movable frame; The movable columns located on both sides of the movable frame are respectively mounted on two groups of the connecting columns, and the two groups of the connecting columns are both mounted with a first spring, and the two ends of the first spring are respectively in contact with the movable column and the fixed frame; A first matching column is arranged on the connecting column located at the center of the movable frame, and a second matching column is arranged at the center of the movable frame. The first matching column is inserted into the second matching column, and a second spring is mounted on the first matching column. Both ends of the second spring are in contact with the movable column and the second matching column respectively.

4. The asymmetric tunnel support structure with extremely small clearance according to claim 3 is characterized in that: The two groups of the first fixed seats on the same side are both provided with support assemblies, the support assemblies include two groups of movable plates, a second hydraulic cylinder is provided between the two groups of movable plates, and limiting columns are provided on both sides of the movable plates, wherein the two groups of limiting columns on one group of movable plates are respectively installed in the two groups of the second fixed seats, and the second fixed seats are provided on both sides of the other group of movable plates, and the corresponding two groups of limiting columns on the movable plates are respectively installed in the two groups of the second fixed seats; The second fixed seat is provided with a ground plug, which is mounted in a large-section tunnel. The second fixed seat is provided with a movable block, which is provided with a sliding groove, and the movable block is slidably mounted in the sliding groove. The ground plug is fixedly connected to the second fixed seat by bolts.

5. The asymmetric tunnel support structure with extremely small clearance according to claim 4 is characterized in that: A third hydraulic cylinder is arranged between the two groups of the second fixing seats on the same side, a group of ground plugs and two groups of slide rails are arranged between the two groups of ground plugs, one end of the two groups of slide rails is respectively fixedly connected to two groups of the ground plugs, and the other end is fixedly connected to the remaining group of ground plugs; The ground plug is provided with a fixing platform, the movable block is provided with a connecting groove, the connecting groove is aligned with the slide rail, and the second fixing seat is provided with a sliding block, the sliding block is aligned with the slide rail.

6. The asymmetric tunnel support structure with extremely small clearance according to claim 5 is characterized in that: Several groups of the first fixed seats are each provided with a fixed block, the fixed block is provided with a first matching block, the first matching block is sleeved with a second matching block, the second matching block is in contact with the inner wall of the large-section tunnel, and a first hydraulic cylinder is provided between the first matching block and the second matching block.

7. The asymmetric tunnel support structure with extremely small clearance according to claim 6 is characterized in that: A plurality of connection components are arranged between the two groups of the fixing frames, and the connection components include a connection sleeve, the connection sleeve is fixedly connected to one group of the fixing frames, and a connection block is arranged on the other group of the fixing frames, and the connection block is slidably mounted in the connection sleeve, and pin holes are provided on the connection sleeve and the connection block, and fixing pins are inserted into the two groups of pin holes; A connecting frame is arranged on the connecting sleeve, the connecting frame is in contact with the connecting sleeve, and a plurality of groups of fixing pins are fixedly connected to the connecting frame.

8. An asymmetric minimum clearance tunnel construction method, characterized in that: The steps include: S1: First, excavate the pilot tunnel. After the pilot tunnel is excavated for a certain distance, start excavating the small-section tunnel. The excavation distance between the pilot tunnel and the small-section tunnel is 40m. While excavating the small-section tunnel, insert several groups of first anchor bolts into the rock mass along the radial direction of the small-section tunnel, and insert several groups of second anchor bolts in the direction of the large-section tunnel. S2: After the small-section tunnel is excavated for a certain distance, the large-section tunnel is excavated. The excavation distance between the small-section tunnel and the large-section tunnel is 60m. While excavating the large-section tunnel, the third anchor is inserted into the rock mass along the radial direction of the large-section tunnel. At the same time, it is necessary to prevent the third anchor from crossing the second anchor. When excavating the large-section tunnel, a support mechanism is required to provide initial support for the large-section tunnel in the excavation area, and then secondary lining is performed. The distance between the initial support and the secondary lining is maintained at 5m, which can most effectively ensure the structural strength of the large-section tunnel. S3: When initially supporting a large-section tunnel, the staff first moves the support mechanism to the place where the large-section tunnel needs to be initially supported, and then uses the ground plug to cooperate with the second hydraulic cylinder to fix the support mechanism and support the large-section tunnel at the same time. Then, the first hydraulic cylinder drives the second matching block to move so that the second matching block contacts the side wall of the large-section tunnel to support the side wall of the large-section tunnel. S4: As the large-section tunnel is continuously excavated, the support mechanism needs to be moved accordingly. When moving the support mechanism, the staff first removes the bolts between the two sets of second fixing seats and the two sets of ground plugs at the rear, then moves the connecting frame to separate the fixing pins from the pin holes, and then starts the two sets of third hydraulic cylinders at the same time. The two sets of third hydraulic cylinders drive a set of support components at the rear to move until the third hydraulic cylinders are fully retracted, and then the ground plugs are fixed to the corresponding movable blocks by bolts. At this time, the distance between the two sets of support components is relatively close; S5: Then the staff separates the slide rail near the rear from the ground plug at the center, moves the slide rail and the ground plug to the front of the support mechanism, and fixes the slide rail on one of the ground plugs. Then the staff removes the bolts between the two groups of second fixing seats and the two groups of ground plugs in the front, and then drives the support assembly in the front to move forward through the third hydraulic cylinder until the third hydraulic cylinder is fully extended, and then fixes the second fixing seat to the corresponding ground plug through bolts. Finally, the staff moves the connecting frame so that the fixing pin is clamped in the pin hole to complete the forward movement of the support mechanism.

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