Emergency supporting structure for small-diameter TBM tunnel excavation

Abstract

The emergency supporting structure comprises a supporting layer and a plurality of anchor rods and anchor cables which penetrate through the supporting layer to be anchored to surrounding rock, the supporting layer comprises a plurality of supporting annular units which are arranged in the longitudinal direction of a tunnel, and each supporting annular unit is formed by connecting a plurality of corrugated plate single bodies in the annular direction of the tunnel; the anchor rod penetrates through the supporting layer to be anchored in the tunnel surrounding rock and extends out of the tail of the tunnel surrounding rock to be fixedly connected to the supporting layer. The anchor cable is anchored to the tunnel surrounding rock and extends out of the tail of the tunnel surrounding rock to be connected with the supporting layer; angles where the anchor rods and the anchor cables are anchored into surrounding rock are perpendicular to a tunnel excavation contour line. The supporting system can carry out emergency supporting when unfavorable geology is encountered in the tunnel excavation of the small-diameter TBM, the influence of rock stratum collapse on the small-diameter TBM is prevented, the excavation efficiency is improved, the economic loss is reduced, and meanwhile, the construction safety is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of support for small-diameter TBM tunnel excavation, in particular to an emergency support structure for small-diameter TBM tunnel excavation. Background Art

[0002] At present, my country often uses open TBM for excavation in the field of tunnels. Small-diameter TBMs are used for tunnel construction in the fields of urban infrastructure, subways, drainage, electricity and communications, including urban subway tunnels, drainage corridors, gravity drainage wells, fiber optic tunnels, etc. In the process of small-diameter TBM excavation, the excavation channel is narrow, and the space for emergency support equipment and personnel is limited. Small-diameter TBMs are more sensitive to weak or broken strata. If they encounter unfavorable geology, such as fault zones usually accompanied by broken rocks and loose fillings, these geological structures may cause TBM jams and loss of control of excavation direction, which seriously affects the efficiency of tunnel excavation, wastes resources, causes economic losses, and increases the safety risks of operators. Therefore, emergency support plans need to be carefully designed.

[0003] Emergency support for small-diameter TBMs in China mostly uses the installation of steel bar rows and channel steels. First, holes are drilled at the locations that need support according to the designed spacing, with the hole diameter matching the steel bar diameter. The steel bars are inserted into the holes and fixed with anchor glue or concrete to form steel bar rows. Secondly, channel steels are installed. Channel steels are placed as needed on the excavation surface or in potentially unstable areas. Channel steels can be used as beams or columns. One end of the channel steel is fixed on the steel bar row, and the other end can be fixed to the surrounding rock or other structures with bolts or other connectors. High-strength connectors are then used to connect the steel bar row and the channel steel to form a stable support system. After the steel bar row and channel steel are installed, concrete is sprayed to form a protective layer. There are also emergency support methods such as erecting steel arches, advanced emergency spraying, and applying pre-mounted advanced pipe sheds or advanced small pipe supports. Although the above methods can improve the bearing capacity of the surrounding rock to a certain extent, they are not well suited for small-diameter TBMs. The working space is narrow, and these emergency supports occupy a lot of space, which may make it difficult for the tunnel boring machine to enter or cause equipment damage, thus seriously affecting the efficiency of tunnel construction. Utility Model Content

[0004] In view of the deficiencies of the above-mentioned prior art, the purpose of the utility model is to provide an emergency support structure for small-diameter TBM tunnel excavation, which can perform emergency support in the narrow space of small-diameter TBM excavation, solving the problem that small-diameter TBM is prone to getting stuck and losing control of the excavation direction when encountering poor geology during the excavation process, thereby improving construction efficiency and avoiding economic losses caused by waste of resources. At the same time, it also reduces the exposure time of construction personnel in potentially dangerous environments and ensures the safety of construction.

[0005] In order to solve the above problems, the utility model discloses an emergency support structure for small-diameter TBM tunnel excavation, comprising a support layer arranged facing the tunnel surrounding rock, a plurality of anchor rods and a plurality of anchor cables, wherein the support layer comprises a plurality of support annular units arranged along the longitudinal direction of the tunnel, each support annular unit is formed by connecting a plurality of corrugated plate monomers in the tunnel annular direction, each corrugated plate monomer is a wavy curved structure with crests and troughs in the longitudinal direction of the tunnel, so that the support layer as a whole forms a hyperbolic arch structure; the anchor rod passes through the support layer and is anchored in the tunnel surrounding rock, and the tail portion extending out of the tunnel surrounding rock is fastened to the support layer; the anchor cable is anchored in the tunnel surrounding rock and the tail portion extending out of the tunnel surrounding rock is connected to the support layer; the angle at which the anchor rod and the anchor cable are anchored into the surrounding rock is perpendicular to the tunnel excavation contour line.

[0006] The support structure based on the utility model has the advantages of quick construction and good support effect. The thinner support layer imposes less load on the cutter and propulsion system of the tunnel boring machine, which helps to extend the service life of the equipment. The fast assembled support can enable the TBM to penetrate forward faster, reduce construction time, save subsequent primary support, waterproof layer and secondary lining operation time, and also reduce the exposure time of construction personnel in potentially dangerous environments, thereby improving safety.

[0007] The utility model has the advantages of simple process and good emergency support effect for small-diameter TBMs with insufficient space for emergency support operations. The thickness of the steel sections of common tunnel emergency supports is 100-250mm, or even thicker. Therefore, the support system of the utility model can reduce the thickness of the emergency support layer to the greatest extent, save the time for TBM forward excavation construction, reduce the subsequent operating pressure of primary support, waterproof layer and secondary lining, and effectively solve the problem of jamming of small-diameter TBM machines caused by collapse and falling of blocks due to poor support, avoid economic losses caused by waste of resources, reduce the exposure time of construction personnel in potential dangerous environments, and improve the inherent safety of construction.

[0008] Furthermore, it also includes a waterproof concrete layer, which is arranged on the side of the supporting layer away from the tunnel surrounding rock.

[0009] Furthermore, positioning holes for the anchor rods to pass through are arranged on the supporting layer, and the positioning holes and the supporting holes are evenly spaced and distributed in the circumferential direction and the longitudinal direction of the supporting layer.

[0010] Furthermore, the support hole is constructed as a grouting hole capable of grouting, so that waterproof slurry can be injected into the outer surface groove formed by the corrugated curved structure of the corrugated plate monomer in the partial area of ​​the support layer facing the tunnel surrounding rock, so that the outer surface groove forms a concrete drainage channel that guides the surrounding rock seepage to the arch foot; and the support hole is also constructed to be closed after the grouting is completed, and opened when the anchor cable needs to be installed, so that the anchor cable can be anchored to the tunnel surrounding rock from the support hole in the area in the partial area of ​​the support layer. This makes it possible to drain the water in the rock formation to the tunnel arch foot through the concrete drainage channel formed by the outer surface groove of the corrugated plate monomer when encountering a rock formation in a strong water-rich area, greatly improving the waterproof ability of the support system, avoiding the influence and damage of the seepage in the rock formation on the support structure, and ensuring the stability and safety of the entire support system.

[0011] Furthermore, the concrete drainage channel is formed in the corresponding area of ​​the supporting layer corresponding to the strong water-rich area of ​​the tunnel surrounding rock.

[0012] Further, the thickness of the corrugated board monomer is 3-12 mm, and the wave height of the corrugated board monomer is 20-100 mm, and the wave width is 150-400 mm.

[0013] Furthermore, after being anchored on the tunnel surrounding rock, the anchor rod (3) and / or the anchor cable (4) are prestressed to enhance the bonding force between the anchor rod (3) and the tunnel surrounding rock.

[0014] Furthermore, the positioning hole (5) and / or the supporting hole (6) are pre-arranged on the corrugated board unit (2) in the factory.

[0015] The utility model has the following beneficial effects compared with the prior art: the emergency support structure of the utility model can adapt to the narrow space within the excavation of a small diameter TBM, and can perform effective emergency support when encountering adverse geological conditions during the TBM excavation process. By setting the structural coordination of the support layer, anchor rods and anchor cables, the stability of the emergency support structure is greatly enhanced, so that it can solve the problem of machine jamming and loss of control of the excavation direction caused by surrounding rock collapse and rock stratum shedding due to insufficient support strength when a small diameter TBM encounters adverse geological conditions during the excavation process, thereby improving construction efficiency, while also avoiding waste of resources, saving economic costs, and reducing the exposure time of construction personnel in potentially dangerous environments, ensuring construction safety.

[0016] The emergency support structure for small-diameter TBM tunnel excavation of the present invention is disclosed in detail below with reference to the embodiments and reference numerals shown in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the cross-sectional structure of the emergency support structure of the utility model;

[0018] Figure 2 It is a schematic diagram of the connection of the first embodiment of the corrugated plate monomers of adjacent supporting annular units of the utility model;

[0019] Figure 3 It is a schematic diagram of the connection of adjacent corrugated plate monomers of the supporting annular unit of the utility model in the first embodiment;

[0020] Figure 4 It is a schematic diagram of the connection of the corrugated plate monomers of adjacent supporting annular units and the adjacent corrugated plate monomers of the supporting annular units according to the utility model in a second embodiment;

[0021] Figure 5 for Figure 4 An enlarged schematic diagram of the connection hole in the second embodiment;

[0022] Figure 6 This is a distribution diagram of the positioning holes and support holes on the corrugated plate monomer along the longitudinal direction of the tunnel of the utility model;

[0023] Figure 7 This is a schematic diagram of the installation structure of the utility model along the longitudinal direction of the tunnel anchor rod on the corrugated plate monomer;

[0024] Figure 8 It is a schematic diagram of anchor rod and anchor cable support on the support layer of the utility model;

[0025] Fig. 9 It is a distribution diagram of positioning holes and supporting holes on the cross section of the emergency supporting structure of the utility model;

[0026] Fig.10 It is an enlarged schematic diagram of the anchor rod installation structure of the emergency support structure of the utility model;

[0027] Fig.11 This is a schematic diagram of the longitudinal section position of the emergency support system construction of the utility model.

[0028] Reference numerals

[0029] 1 support annular unit, 2 corrugated plate monomer, 3 anchor rod, 4 anchor cable, 5 positioning hole, 6 support hole, 7 connection piece,

[0030] 8 annular lap joint, 9 annular connector, 10 strip-shaped elongated hole, 10a positioning hole portion, 10b U-shaped interference hole portion, 11 high-strength bolt, 12 anchor plate, 13 nut. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0033] The utility model discloses an emergency support structure for small-diameter TBM tunnel excavation, comprising:

[0034] The supporting layer is arranged facing the surrounding rock of the tunnel, and the supporting layer includes a plurality of supporting annular units 1 arranged in the longitudinal direction of the tunnel, and each supporting annular unit 1 is formed by connecting a plurality of corrugated plate monomers 2 in the annular direction of the tunnel, and each corrugated plate monomer 2 is a wavy curved structure with crests and troughs in the longitudinal direction of the tunnel, so that the supporting layer as a whole forms a hyperbolic arch structure;

[0035] A plurality of anchor rods 3, which pass through the supporting layer and are anchored inside the tunnel surrounding rock, and the tails extending out of the tunnel surrounding rock are fastened to the supporting layer;

[0036] A plurality of anchor cables 4, which are anchored to the tunnel surrounding rock and extend out of the tail of the tunnel surrounding rock to form a connection with the supporting layer;

[0037] Among them, a plurality of support holes 6 are provided on the support layer, and the support holes 6 are constructed as grouting holes capable of grouting, so that waterproof slurry can be injected into the outer surface groove formed by the corrugated curved structure of the corrugated plate monomer 2 in the partial area of ​​the support layer facing the tunnel surrounding rock, so that the outer surface groove forms a concrete drainage channel for guiding the surrounding rock seepage water to the arch foot;

[0038] Furthermore, the support hole 6 is also configured to be closed after grouting is completed, and opened when the anchor cable 4 needs to be installed, so that the anchor cable 4 can be anchored to the tunnel surrounding rock from the support hole 6 in a partial area of ​​the support layer.

[0039] When the support system of the utility model is in use, the support layer of the hyperbolic arch structure is located between the surrounding rock and the TBM body, the anchor rod is a high-strength threaded steel bar, and the main part of the anchor cable is composed of high-strength steel strands. After the support layer of the hyperbolic arch structure is erected, the anchor rod and the anchor cable are driven into the surrounding rock through the positioning hole and the support hole to improve the stability and bearing capacity of the surrounding rock. The nut is located at the tail of the anchor rod and the anchor cable after being driven into the surrounding rock, and fits tightly with the pad to play a fixing role. The positioning hole and the support hole are arranged at equal intervals in the horizontal and vertical directions of the support layer of the hyperbolic arch structure respectively. The positioning hole is the anchor rod hole, which is pre-drilled by the factory at the fixed position of the corrugated plate unit. The support hole is first a grouting hole, so that waterproof slurry can be injected into the outer surface groove formed by the corrugated bending structure of the corrugated plate monomer 2 in the partial area of ​​the support layer facing the tunnel surrounding rock. At the same time, the support hole is also an anchor cable hole, so that the anchor cable can be driven into the actual required position during the later system support.

[0040] When the emergency support structure of the utility model is used in practice, the support layer of the hyperbolic arch structure matches the excavated tunnel body, and can be prefabricated in the factory into a corresponding short anchor + special-shaped corrugated plate emergency support structure according to the different curvatures of the tunnel body. It is suitable for emergency support of small-diameter TBMs of 3.5m and below.

[0041] In a preferred embodiment, a waterproof concrete layer is also included, which is arranged on the side of the support layer away from the tunnel surrounding rock. Specifically, after the emergency support structure is screwed on and the support hole is closed, concrete can be sprayed on the inner side of the support layer of the hyperbolic arch structure (the side away from the surrounding rock), and a waterproofing agent can be added inside the concrete, or a waterproof board can be laid on the surface of the sprayed concrete to solve the water seepage problem after TBM excavation; the grade strength of the sprayed concrete is increased at the arch waist position to provide sufficient support shoe pressure strength for subsequent excavation of small-diameter TBMs.

[0042] like Figure 8 and Fig. 9 As shown, in a preferred embodiment, the support layer is provided with positioning holes 5 for the anchor rods 3 to pass through, and the positioning holes 5 and the support holes 6 are evenly spaced in the circumferential and longitudinal directions of the support layer. It is preferred that the positioning holes 5 and the support holes 6 are spaced every 800 mm in the circumferential direction of the support layer and every 1000 mm in the longitudinal direction, so that the support layer after the anchor rods 3 and the anchor cables 4 are anchored can more evenly disperse the stress load of the surrounding rock, effectively preventing the problem of local collapse and falling off caused by deformation of some weak and sensitive rock layers due to uneven stress distribution inside the surrounding rock, greatly improving the stability of the surrounding rock and ensuring the safety of tunnel construction.

[0043] In a preferred embodiment, the concrete drainage channel is formed on the supporting layer in a corresponding area to the strong water-rich area of ​​the tunnel surrounding rock.

[0044] In the embodiment of the utility model, when the surrounding rock grade is poor, the TBM excavation face is heavily loaded, and the geological conditions are poor, the thickness of the corrugated plate monomer 2 can be increased to improve the bearing capacity of the support layer, but the thickness of the corrugated plate monomer 2 should not be too large. When the thickness exceeds 12 mm, the support layer is in an elastic stage throughout the entire process when it is loaded. The increase in thickness has no significant effect on the displacement control of the structure. Too much thickness will also cause a sharp increase in weight and increase the difficulty of support. When the surrounding rock grade is good, the TBM excavation face is lightly loaded, and the geological conditions are good, the thickness of the corrugated plate monomer 2 is appropriately reduced to save materials and reduce the weight of the emergency support structure. The thickness of the corrugated plate monomer 2 can be flexibly adjusted between 3-12 mm.

[0045] Moreover, when the surrounding rock grade is poor, the TBM excavation face is subject to heavy load, and the geological conditions are poor, the wave height of the corrugated plate monomer 2 is appropriately increased and the wave width of the corrugated plate monomer 2 is reduced to a certain extent to improve the bearing capacity of the support layer. The wave height and wave width of the corrugated plate monomer 2 can be flexibly adjusted between 20-100mm and 150-400mm respectively.

[0046] In a preferred embodiment, the thickness of the corrugated plate monomer 2 is 10 mm, the wave height is 50 mm, and the wave width is 200 mm. The theoretical stiffness of the corrugated plate monomer 2 with a thickness of 10 mm is 70 times that of the flat plate structure with the same material dosage, and the supporting layer can better exert the self-bearing capacity of the surrounding rock.

[0047] In a preferred embodiment, the anchor rod 3 and / or the anchor cable 4 are prestressed after being anchored on the tunnel surrounding rock to enhance the bonding force between the anchor rod 3 and / or the anchor cable 4 and the tunnel surrounding rock.

[0048] like Figure 6 As shown, in a preferred embodiment, the positioning holes 5 and / or the supporting holes 6 are pre-set in the factory on the corrugated sheet monomer 2. Since the positioning holes 5 and the supporting holes 6 are pre-set and fixed in the factory and directly used at the support site, the construction process of anchoring the anchor rod 3 and supporting the anchor cable 4 is accelerated, and the work efficiency is improved.

[0049] like Figure 2 and Figure 3 As shown, in one embodiment, the surfaces of two adjacent longitudinal corrugated plate monomers 2 are first connected to each other by a connecting piece 7, and then fixed by a high-strength bolt 11, and a certain tightening force is applied to increase the friction between the corrugated plate monomers 2, and the bolt rod is mainly subjected to shear force; the two adjacent transverse (i.e., annular) corrugated plate monomers 2 are connected by overlapping each other through the connecting piece 7 to achieve the purpose of avoiding the corrugated plate unit from slipping.

[0050] like Figure 1 , Figure 4 and Figure 5As shown, in another preferred embodiment, two circumferentially adjacent corrugated plate monomers 2 are respectively provided with an annular overlap portion 8, and the annular overlap portions 8 are connected to adjacent corrugated plate monomers 2 by means of connecting holes and annular connecting members 9 matched with the connecting holes. The connecting hole on the annular overlap portion 8 of at least one of the adjacent corrugated plate monomers 2 is a strip-shaped elongated hole 10, and is constructed together with the connecting member to allow the corrugated plate monomer 2 to produce relative displacement when subjected to annular pressure, so as to adapt to the deformation and stress of the tunnel surrounding rock in the annular direction. Furthermore, the strip-shaped elongated hole 10 includes a positioning hole portion 10a and a U-shaped interference hole portion 10b that passes through the positioning hole portion 10a, and the annular connector 9 can extend from the positioning hole portion 10a to form a connection between the annular overlapping portions 8 of adjacent corrugated plate monomers 2; the strip-shaped elongated hole 10 and the annular connector 9 are jointly constructed so that when the corrugated plate monomer 2 is not subjected to annular pressure, the annular connector 9 remains in the positioning hole portion 10a, and when the corrugated plate monomer 2 is subjected to annular pressure and exceeds the rated pressure, the annular connector 9 can enter the U-shaped interference hole portion 10b from the positioning hole portion 10a under the action of pressure and form an interference fit with the U-shaped interference hole portion 10b. At the same time, the strip-shaped elongated hole 10 is arranged on the connecting part of the corrugated retaining plate located below in the circumferential direction among the adjacent corrugated plate monomers 2, and the connecting hole on the connecting part of the corrugated plate monomer 2 located above in the circumferential direction among the adjacent corrugated plate monomers 2 is a conformal hole adapted to the shape of the circumferential connecting piece 9.

[0051] In addition, preferably, in the longitudinal direction of the tunnel, the corrugated plate monomers 2 of adjacent supporting annular units 1 respectively have longitudinal overlapping portions, wherein the longitudinal overlapping portion of the corrugated plate monomer 2 of one supporting annular unit 1 is provided with a longitudinally extending strip stretching hole, and the strip stretching hole includes a longitudinal positioning hole portion and a longitudinal U-shaped interference hole portion, and the longitudinal overlapping portion of the corrugated plate monomer 2 of the other supporting annular unit 1 is provided with a conformal hole adapted to the shape of the longitudinal connecting piece; the strip stretching hole and the longitudinal connecting piece are jointly constructed so that when the longitudinal pressure applied to the corrugated retaining plate exceeds the deformation pressure that its own wave crests and wave troughs can resist, the longitudinal connecting piece can enter the longitudinal U-shaped interference hole portion from the longitudinal positioning hole portion and form an interference fit with the longitudinal U-shaped interference hole portion.

[0052] In the present invention, the mass of the corrugated sheet unit 2 with a width of 1m is about 9.82kg, and the steel density is 7.85g / cm 3Under the same conditions, the weight of the steel bar row and channel steel support adopted for emergency support is about 10kg, of which the steel bar row adopts Φ16mm steel bar, the steel bar spacing is 200mm, the channel steel specification is 100×50×5 (height×width×thickness), and the length is 1 meter. In comparison, the self-weight of the corrugated plate monomer 2 is lighter, and its transportation and installation are faster and more efficient. At the same time, in order to reduce the self-weight and save space and reduce the difficulty of construction while meeting the requirements of support strength, the wave height and thickness of the corrugated plate monomer 2 can also be appropriately reduced, and it can be prefabricated by the factory, which has a higher degree of flexibility.

[0053] In the emergency support structure of the utility model, in some TBMs with smaller diameters, the annular hyperbolic arch structure support unit of the excavated hole can appropriately reduce the number of overlaps of the corrugated plate monomers, but the minimum number should not be less than 3 for the convenience of transportation and installation.

[0054] The small-diameter TBM tunnel excavation emergency support structure of the utility model is constructed by the following method. When the small-diameter TBM excavates the tunnel, the geological conditions suddenly change, such as encountering faults, weak interlayers, water gushing, rock bursts, etc. These conditions may cause the stability of the tunnel surrounding rock to decrease. At this time, emergency support is required, and the assembly is completed from the outside to the inside in the tunnel. Among them, the circumferential curvature of the support layer matches the surrounding rock of the excavated tunnel. The method includes the following steps:

[0055] S1, at the position where the tunnel needs to be supported, the corrugated plate monomers 2 are overlapped in sequence along the tunnel circumference from the arch foot to the arch top to form a supporting circumferential unit 1; wherein, in the supporting circumferential unit 1, the corrugated plate monomer 2 located at the top is always overlapped on the outside of the corrugated plate monomer 2 located at the bottom;

[0056] S2, installing the anchor rod 3, passing through the corrugated plate unit 2 and anchoring it inside the tunnel surrounding rock, and the tail extending out of the tunnel surrounding rock is fastened to the corrugated plate unit 2 at the location;

[0057] S3, constructing a support hole 6 on the corrugated plate unit 2;

[0058] Determine the water richness of the surrounding rock in the tunnel area. When it is determined that the water richness exceeds the threshold, fill the waterproof slurry into the outer surface groove of the support annular unit 1 facing the tunnel surrounding rock through the support hole 6 in the area. After the grouting is completed, close the support hole 6; when it is determined that the water richness does not exceed the threshold, directly proceed to the next step;

[0059] S4, installing a steel arch frame in the inverted arch area of ​​the supporting annular unit 1 and filling with grouting;

[0060] S5, advancing the TBM machine forward, judging whether it is necessary to install the anchor cable 4 according to the surrounding rock strength in the advancing area; if it is judged that it is necessary to install, opening the support hole 6, so as to install the anchor cable by means of the support hole 6;

[0061] S6, installing the next supporting ring toward the unit 1 in sequence along the longitudinal direction of the tunnel, and repeating steps S2-S5 to form a final supporting layer.

[0062] Based on the above-disclosed steps, the utility model realizes emergency support during small-diameter TBM tunnel excavation, and solves the problem of machine jamming and loss of control of excavation direction caused by surrounding rock collapse and rock stratum shedding due to insufficient support strength when a small-diameter TBM encounters poor geology during the excavation process. It ensures the efficiency of construction operations, reduces economic losses, and improves the safety of operators.

[0063] like Figure 7 and Fig.10 As shown, in the embodiment of the utility model, in step S2, the anchor rod 3 is a high-strength threaded steel bar, and the tail portion thereof extending out of the tunnel surrounding rock is provided with an anchor rod pad 12 and a nut 13, the nut 13 matches the anchor rod 3, and the anchor rod pad 12 is tightly fitted on the corrugated plate monomer 2 through a threaded connection, thereby enhancing the structural stress of the anchor rod 3 on the tunnel surrounding rock, improving the bearing capacity of the surrounding rock, thereby effectively controlling the deformation of the surrounding rock, avoiding the occurrence of tunnel collapse accidents, and ensuring the safety of the operators.

[0064] In a preferred embodiment, between step S3 and step S4, it further includes: after grouting is completed with the aid of the support hole 6 and the support hole 6 is closed, spraying waterproof concrete on the inner side of the support ring unit 1 away from the tunnel surrounding rock to form a waterproof concrete layer.

[0065] In the embodiment of the utility model, when grouting is required through the support hole 6, in order to solve the end plugging problem, a wooden board plugging method is adopted, and the specific method is as follows: first, according to the cross-sectional size of the tunnel, a suitable wooden board is cut and placed at the end of the area to be filled; secondly, the wooden board is fixed, and the wooden board is firmly fixed to the tunnel wall with steel nails to ensure that the wooden board is stable and will not shift during the pouring process; then a sealing treatment is performed: the gap between the wooden board and the tunnel wall is covered with a waterproof cloth or a plastic film to prevent the slurry from leaking. Finally, after the slurry reaches the designed strength, the plugging material is removed to ensure the smooth progress of the next stage of construction.

[0066] In the embodiment of the utility model, in step S5, the anchor cable 4 support operation is quickly started in the area where the surrounding rock has poor self-stabilization ability and is more prone to collapse or instability, the support hole 6 is opened and the cover is screwed, the hole is drilled and the anchor cable 4 is driven in. If the support layer after driving the anchor rod 3 and grouting can provide sufficient support force, the anchor cable 4 support is not required, and it is flexibly adjusted according to the specific situation. The construction of the emergency support structure of the utility model is carried out at the support system of the small-diameter TBM machine. At this time, the TBM machine support shoe is retracted, the rear support is opened, and after the emergency support is completed, the TBM machine is pushed forward 25-75m, and then the next round of emergency support stage is carried out.

[0067] like Figure 8 and Fig.11 As shown, in a preferred embodiment, the anchor rod 3 and the anchor cable 4 are equipped with an anchor drilling rig, and the angle at which the anchor rod 3 and the anchor cable 4 are driven into the surrounding rock is perpendicular to the tunnel excavation contour line, so that the suspension function can be better exerted, and the weight of the tunnel surrounding rock can be transferred to a more stable rock formation, thereby improving the stability of the surrounding rock.

[0068] In addition, in the support system and support method of the present invention, when laying and installing anchor rods, 2-4 anchor rods are selected for each corrugated plate unit for axial force testing, and whether to construct long or short anchor rods or anchor cables is determined based on the test results (about 40% of positioning holes and support holes are reserved to deal with insufficient support strength, and long anchor rods can be installed later depending on the monitoring situation). At the same time, the corrugated plate units are overlapped as appropriate. If overlapping is required, the overlapping anchor rod holes must be retained and cannot be used for positioning.

[0069] In addition, in areas with better surrounding rock grades, short anchor rods are set. Short anchor rods can use 16-25mm, 2-5m long high-strength threaded steel bars. The anchor length of short anchor rods is not less than 95% of its length. In areas with poor surrounding rock grades, short anchor rods and anchor cables are used for joint support, and the method of alternate setting is adopted. The anchor cables can use 15-20mm, 8m long high-strength steel strands, and the anchor length of anchor cables is not less than 6m. In addition, in areas with poor surrounding rock self-stabilization ability and more prone to collapse or instability, the anchor cable support operation is quickly started, the support hole is opened and the cap is screwed, and the hole is drilled and the anchor cable is driven in. If the hyperbolic arch structure after the short anchor rod is driven in and grouting can provide sufficient support, there is no need for anchor cable support. If conditions permit, system support can also be carried out, and flexible adjustments can be made according to specific circumstances. The construction of this emergency support structure is carried out at the support system of the small-diameter TBM machine. At this time, the TBM machine support shoes are retracted and the rear support is opened. After completing the emergency support, the TBM machine is pushed forward 25-75m and then the next round of emergency support phase is carried out.

[0070] In the support system and support method of the utility model, the specific implementation process of grouting the support hole is as follows: when the small-diameter TBM excavates to a water-rich area, the groove on the outer surface of the hyperbolic arch support layer is filled with waterproof concrete, and at the same time, a concrete reinforcing agent such as fiber or capsule is used to improve the flow resistance of the concrete. This makes it possible that when the small-diameter TBM excavates to a water-rich area, the groove on the outer surface of the hyperbolic arch serves as a drainage channel, and groundwater flows from the top to the arch foot along the tunnel circumference, and a drainage ditch is arranged at the bottom of the hyperbolic arch structure along the tunnel longitudinal direction.

[0071] Moreover, when filling the concrete slurry, in order to solve the end blocking problem, the wooden board blocking method is used. The specific method is as follows: first, according to the cross-sectional size of the tunnel, cut the appropriate wooden board and place it at the end of the area to be filled; second, fix the wooden board and use steel nails to firmly fix the wooden board on the tunnel wall to ensure that the wooden board is stable and will not shift during the concrete pouring process; then seal it: cover the gap between the wooden board and the tunnel wall with waterproof cloth or plastic film to prevent concrete slurry from leaking. Finally, after the concrete reaches the designed strength, remove the blocking material to ensure the smooth progress of the next stage of construction.

[0072] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. An emergency support structure for small-diameter TBM tunnel excavation, characterized in that: The invention comprises a supporting layer arranged facing the surrounding rock of the tunnel, a plurality of anchor rods and a plurality of anchor cables, wherein the supporting layer comprises a plurality of supporting annular units (1) arranged in the longitudinal direction of the tunnel, each supporting annular unit (1) is formed by connecting a plurality of corrugated plate monomers (2) in the annular direction of the tunnel, each corrugated plate monomer (2) is a wavy curved structure having crests and troughs in the longitudinal direction of the tunnel, so that the supporting layer as a whole forms a hyperbolic arch structure; The anchor rod (3) passes through the supporting layer and is anchored inside the tunnel surrounding rock, and the tail portion extending out of the tunnel surrounding rock is fastened to the supporting layer; the anchor cable (4) is anchored in the tunnel surrounding rock and the tail portion extending out of the tunnel surrounding rock is connected to the supporting layer; The angle at which the anchor rod (3) and the anchor cable (4) are anchored into the surrounding rock is perpendicular to the tunnel excavation contour line.

2. The emergency support structure for small-diameter TBM tunnel excavation according to claim 1, characterized in that: It also includes a waterproof concrete layer, which is arranged on the side of the supporting layer away from the tunnel surrounding rock.

3. The emergency support structure for small-diameter TBM tunnel excavation according to claim 2, characterized in that: The support layer is provided with positioning holes (5) for the anchor rods (3) to pass through, and the positioning holes (5) and the support holes (6) are evenly spaced and distributed in the circumferential and longitudinal directions of the support layer.

4. The emergency support structure for small-diameter TBM tunnel excavation according to claim 3, characterized in that: The support hole (6) is constructed as a grouting hole capable of grouting, so that waterproof slurry can be injected into the outer surface groove formed based on the wave-shaped curved structure of the corrugated plate monomer (2) in the partial area of ​​the support layer facing the tunnel surrounding rock, so that the outer surface groove forms a concrete drainage channel for guiding the surrounding rock seepage water to the arch foot; Furthermore, the support hole (6) is also configured to be closed after grouting is completed, and to be opened when the anchor cable (4) needs to be installed, so that the anchor cable (4) can be anchored to the tunnel surrounding rock from the support hole (6) in a partial area of ​​the support layer.

5. The emergency support structure for small-diameter TBM tunnel excavation according to claim 4, characterized in that: The concrete drainage channel is formed on the supporting layer in a corresponding area of ​​the strong water-rich area of ​​the tunnel surrounding rock.

6. The emergency support structure for small-diameter TBM tunnel excavation according to claim 5, characterized in that: The thickness of the corrugated plate monomer (2) is 3-12 mm, the wave height of the corrugated plate monomer (2) is 20-100 mm, and the wave width is 150-400 mm.

7. The emergency support structure for small-diameter TBM tunnel excavation according to claim 6, characterized in that: After being anchored on the tunnel surrounding rock, the anchor rod (3) and / or the anchor cable (4) are prestressed to enhance the bonding force between the anchor rod (3) and / or the anchor cable (4) and the tunnel surrounding rock.

8. The emergency support structure for small-diameter TBM tunnel excavation according to claim 7, characterized in that: The positioning holes (5) and / or the supporting holes (6) are pre-arranged on the corrugated board unit (2) in the factory.

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