Supporting structure and method suitable for underground pipe gallery under excavation crossing fault zone

Abstract

The application discloses a supporting structure and method suitable for underground pipe gallery underground excavation crossing a fracture zone, and relates to the technical field of underground pipe galleries. The supporting structure comprises a steel arch assembly arranged adjacent to the fracture zone and used for supporting the tunnel, the top of the steel arch assembly is connected with a vault anchor rod assembly which is inserted into the surrounding rock in a longitudinal oblique upward direction of the tunnel and penetrates through the fracture zone, and the bottom of the steel arch assembly is connected with a inverted arch anchor rod assembly which is inserted into the surrounding rock in a longitudinal oblique downward direction of the tunnel and penetrates through the fracture zone. The application sets the steel arch assembly, the vault anchor rod assembly and the inverted arch anchor rod assembly, on the one hand, the surrounding rocks on both sides of the upper fracture zone of the tunnel are connected together to bear force together, preventing the dislocation displacement of the upper surrounding rock caused by the stress loss of the tunnel excavation, on the other hand, the surrounding rocks on both sides of the lower fracture zone of the tunnel are connected together to form a composite foundation, improving the bearing capacity of the lower surrounding rock and effectively preventing the uneven settlement of the lower surrounding rock.

Description

Technical Field

[0001] This application relates to the field of underground utility tunnel technology, specifically to a support structure and method suitable for underground utility tunnels that are excavated through fracture zones. Background Technology

[0002] Underground utility tunnels, also known as utility tunnels, are public tunnels built underground in cities to centrally lay municipal pipelines such as electricity, communications, radio and television, water supply, drainage, heating, and gas.

[0003] Currently, underground utility tunnels are often constructed using methods such as underground excavation, pipe jacking, or tunnel boring. During construction, these tunnels may traverse areas with complex geological structures, such as fault zones caused by complex tectonic movements.

[0004] When underground utility tunnels are excavated through fault zones, steel frames are often used to support the tunnel. However, the support performance of this type of structure is poor, and it is still prone to engineering accidents such as water and mud inrush, excessive deformation of the surrounding rock, and collapse of the tunnel face. Summary of the Invention

[0005] The purpose of this application is to provide a support structure and method suitable for underground utility tunnels that are excavated through fracture zones, thereby solving the problem of poor support performance when underground utility tunnels are excavated through fracture zones.

[0006] The technical solution adopted by this application to solve its technical problem is: a support structure suitable for underground utility tunnels excavated through a fault zone, including a steel arch frame assembly set adjacent to the fault zone and used for tunnel support, the top of the steel arch frame assembly is connected to an arch top anchor assembly that is inserted obliquely upward along the longitudinal direction of the tunnel into the surrounding rock and penetrates the fault zone, and the bottom of the steel arch frame assembly is connected to an inverted arch anchor assembly that is inserted obliquely downward along the longitudinal direction of the tunnel into the surrounding rock and penetrates the fault zone.

[0007] Furthermore, the steel arch frame assembly includes a first steel arch frame and a second steel arch frame disposed on both sides of the fracture zone.

[0008] Furthermore, the arch-top anchor assembly includes a first arch-top anchor and a second arch-top anchor; the first arch-top anchor is inserted obliquely upward into the surrounding rock along the direction from the first steel arch frame to the second steel arch frame and penetrates the fracture zone, and the lower end of the first arch-top anchor is connected to the first steel arch frame; the second arch-top anchor is inserted obliquely upward into the surrounding rock along the direction from the second steel arch frame to the first steel arch frame and penetrates the fracture zone, and the lower end of the second arch-top anchor is connected to the second steel arch frame.

[0009] Furthermore, both the first arch anchor bolt and the second arch anchor bolt comprise multiple bolts, with the multiple first arch anchor bolts and the multiple second arch anchor bolts arranged alternately along the transverse direction of the tunnel.

[0010] Furthermore, the inverted arch anchor assembly includes a first inverted arch anchor and a second inverted arch anchor; the first inverted arch anchor is inserted obliquely downward into the surrounding rock along the direction from the first steel arch frame to the second steel arch frame and penetrates the fracture zone, and the upper end of the first inverted arch anchor is connected to the first steel arch frame; the second inverted arch anchor is inserted obliquely downward into the surrounding rock along the direction from the second steel arch frame to the first steel arch frame and penetrates the fracture zone, and the upper end of the second inverted arch anchor is connected to the second steel arch frame.

[0011] Furthermore, both the first inverted arch anchor bolt and the second inverted arch anchor bolt comprise multiple bolts, with the multiple first inverted arch anchor bolts and the multiple second inverted arch anchor bolts arranged alternately along the transverse direction of the tunnel.

[0012] Furthermore, both the first steel arch frame and the second steel arch frame include an upper arch frame section and a lower arch frame section connected together from top to bottom.

[0013] Furthermore, the steel arch frame assembly is connected to a locking anchor bolt assembly that is inserted into the surrounding rock.

[0014] Furthermore, the anchor bolt assembly includes a first anchor bolt and a second anchor bolt, wherein the first anchor bolt is connected to the first steel arch frame and the second anchor bolt is connected to the second steel arch frame.

[0015] A support method suitable for underground utility tunnels excavated through fracture zones includes:

[0016] When the tunnel is excavated to the first position adjacent to the fault zone, the first arch top anchor rod inserted into the tunnel arch and penetrating the fault zone and the first invert arch anchor rod inserted into the tunnel invert arch and penetrating the fault zone are installed along the tunnel excavation direction. The first locking foot anchor rod is installed and grout is injected into the first locking foot anchor rod. Initial shotcrete is applied to the tunnel section and a steel mesh is installed. The steel mesh is fixedly connected to the first locking foot anchor rod. Then, the first steel arch frame is installed and fixedly connected to the first arch top anchor rod, the first invert arch anchor rod, and the first locking foot anchor rod respectively.

[0017] After the first steel arch frame is completed, the tunnel excavation continues. When the tunnel is excavated to the second position after crossing the fault zone, the second arch top anchor rod inserted into the tunnel arch and penetrating the fault zone and the second invert arch anchor rod inserted into the tunnel invert arch and penetrating the fault zone are installed in the opposite direction of the tunnel excavation. The second locking foot anchor rod is installed and grout is injected into the second locking foot anchor rod. Initial shotcrete is applied to the tunnel section and steel mesh is installed. The steel mesh is fixedly connected to the second locking foot anchor rod. Then the second steel arch frame is installed and fixedly connected to the second arch top anchor rod, the second invert arch anchor rod, and the second locking foot anchor rod.

[0018] After the second steel arch frame is completed, grouting is performed simultaneously on the first arch top anchor, the first invert arch anchor, the second arch top anchor, and the second invert arch anchor.

[0019] The beneficial effects of this application are:

[0020] The support structure and method provided in this application for underground utility tunnels excavated through fracture zones utilize steel arch frame components, arch top anchor bolt components, and invert arch anchor bolt components to form a composite support structure in the fracture zone area of ​​the tunnel. On one hand, this connects the surrounding rock on both sides of the upper fracture zone of the tunnel to share the load, preventing displacement of the upper surrounding rock due to stress loss during tunnel excavation. On the other hand, it connects the surrounding rock on both sides of the lower fracture zone of the tunnel to form a composite foundation, increasing the bearing capacity of the lower surrounding rock and effectively preventing uneven settlement. Therefore, compared with existing technologies, this application improves the support performance of underground utility tunnels excavated through fracture zones, avoiding engineering accidents such as water and mud inrush, excessive surrounding rock deformation, and face collapse during construction, thus enhancing construction safety. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a tunnel excavated through a fault zone.

[0023] Figure 2 This is a schematic diagram of the support structure provided in the embodiments of this application;

[0024] Figure 3 This is a structural schematic diagram of the first steel arch frame;

[0025] Figure 4 This is a structural schematic diagram of the second steel arch frame;

[0026] Figure 5 This is a schematic diagram of the structure in which the first arch anchor bolt and the second arch anchor bolt are arranged in an alternating manner.

[0027] Figure label:

[0028] 10-Tunnel;

[0029] 11-Fault zone;

[0030] 12-Steel arch frame assembly; 121-First steel arch frame; 122-Second steel arch frame; 123-Upper arch frame section; 124-Lower arch frame section;

[0031] 13-Arch top anchor assembly; 131-First arch top anchor; 132-Second arch top anchor;

[0032] 14-Inverted arch anchor bolt assembly; 141-First inverted arch anchor bolt; 142-Second inverted arch anchor bolt;

[0033] 15-Anchor bolt assembly; 151-First anchor bolt; 152-Second anchor bolt. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0035] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the embodiments and features described in these embodiments can be combined with each other unless otherwise specified.

[0036] In the description of the embodiments of this application, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this application is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. The terms "set", "open", "installed", "connected", and "connected" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, and integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0037] See Figure 1 When the underground utility tunnel 10 crosses the fault zone 11 using the cut-and-cover method, the surrounding rock on both sides of the fault zone 11 is prone to displacement due to the geological environment on both sides. Simultaneously, stress loss occurs during the cut-and-cover excavation of tunnel 10. Under the combined effect of these two factors, this type of geological environment is more susceptible to subsidence and collapse. Currently, steel frames are commonly used to support tunnel 10 during cut-and-cover construction of underground utility tunnels. However, this support structure has poor support performance in the fault zone area, still easily causing displacement of the surrounding rock on both sides of the fault zone, leading to engineering accidents such as water and mud inrush, excessive deformation of the surrounding rock, and face collapse, resulting in high construction safety risks.

[0038] To improve the support performance when underground utility tunnels are excavated through fracture zones, see [reference needed]. Figure 2The present application provides a support structure suitable for underground utility tunnels that are excavated through a fault zone. The structure includes a steel arch frame assembly 12 located adjacent to the fault zone 11 and used to support the tunnel 10. The top of the steel arch frame assembly 12 is connected to an arch top anchor bolt assembly 13 that is inserted obliquely upward along the longitudinal direction of the tunnel into the surrounding rock and penetrates the fault zone 11. The bottom of the steel arch frame assembly 12 is connected to an inverted arch anchor bolt assembly 14 that is inserted obliquely downward along the longitudinal direction of the tunnel into the surrounding rock and penetrates the fault zone 11.

[0039] The support structure provided in this application embodiment, applicable to the underground utility tunnel excavation crossing a fault zone, uses a steel arch frame assembly 12 to support the tunnel 10 near the fault zone 11, and to install and support the arch top anchor assembly 13 and the invert arch anchor assembly 14. The arch top anchor assembly 13 is used to inject grout into it to connect the surrounding rock on both sides of the fault zone 11 above the tunnel 10 so that they share the load, preventing displacement of the upper surrounding rock after stress loss during tunnel excavation. The invert arch anchor assembly 14 is used to inject grout into it to connect the surrounding rock on both sides of the fault zone 11 below the tunnel 10 to form a composite foundation, improving the bearing capacity of the lower surrounding rock and effectively preventing uneven settlement of the lower surrounding rock. Therefore, the support structure of this application, by setting up the steel arch frame assembly 12, the arch top anchor bolt assembly 13 and the invert arch anchor bolt assembly 14 connected together, is used to form a composite support structure in the fracture zone area of ​​the tunnel 10, which improves the support performance when the underground utility tunnel is excavated through the fracture zone 11, avoids engineering accidents such as water and mud inrush, excessive deformation of the surrounding rock, and face collapse during construction, and improves the safety of construction.

[0040] In some embodiments, see Figure 2 The steel arch frame assembly 12 includes a first steel arch frame 121 and a second steel arch frame 122 installed on both sides of the fault zone 11. When the tunnel is excavated to the vicinity of the fault zone 11, the first steel arch frame 121 can be installed first. After the tunnel is excavated to cross the fault zone 11, the second steel arch frame 122 can be installed. Thus, the first steel arch frame 121 and the second steel arch frame 122 can be used to support the tunnel 10 on both sides of the fault zone 11, improving the support performance. After the first steel arch frame 121 and the second steel arch frame 122 are installed, if there is a gap between the steel arch frame and the rock surface, it should be filled with shotcrete to prevent point support between the steel arch frame and the rock surface and ensure that the steel arch frame is evenly stressed.

[0041] In some embodiments, see Figure 2 , Figure 3 , Figure 4The arch-top anchor assembly 13 includes a first arch-top anchor 131 and a second arch-top anchor 132. The first arch-top anchor 131 is inserted obliquely upward into the surrounding rock along the direction from the first steel arch frame 121 to the second steel arch frame 122 and penetrates the fracture zone 11. The lower end of the first arch-top anchor 131 is connected to the first steel arch frame 121. The second arch-top anchor 132 is inserted obliquely upward into the surrounding rock along the direction from the second steel arch frame 122 to the first steel arch frame 121 and penetrates the fracture zone 11. The lower end of the second arch-top anchor 132 is connected to the second steel arch frame 122. For example, multiple first arch-top anchors 131 and multiple second arch-top anchors 132 may be included. See [link to documentation]. Figure 5 Multiple first arch anchor bolts 131 and multiple second arch anchor bolts 132 are arranged alternately along the transverse direction of the tunnel. See also Figure 3 Multiple first arch anchor bolts 131 are arranged in an arc shape along the transverse direction of the tunnel, see [reference]. Figure 4 Multiple second arch anchor bolts 132 are arranged in an arc shape along the transverse direction of the tunnel. The number of first arch anchor bolts 131 and second arch anchor bolts 132 can be determined by strength calculation based on the geological conditions at the fault zone 11, and no specific limit is made here. When the tunnel is excavated to the vicinity of the fault zone 11, the first arch anchor bolts 131 can be installed first and connected to the first steel arch frame 121. After the tunnel is excavated to cross the fault zone 11, the second arch anchor bolts 132 are installed and connected to the second steel arch frame 122. Then, grout is injected into the first arch anchor bolts 131 and second arch anchor bolts 132 to connect the surrounding rock on both sides of the fault zone 11 above the tunnel 10 so that they can share the load. Thus, the cooperation of the first arch anchor bolts 131 and second arch anchor bolts 132 can prevent the surrounding rock on both sides of the fault zone above the tunnel from shifting due to stress loss during tunnel excavation, thereby improving the support performance.

[0042] In some embodiments, see Figure 2 , Figure 3 , Figure 4 The inverted arch anchor assembly 14 includes a first inverted arch anchor 141 and a second inverted arch anchor 142. The first inverted arch anchor 141 is inserted obliquely downwards into the surrounding rock along the direction from the first steel arch frame 121 to the second steel arch frame 122 and penetrates the fracture zone 11. The upper end of the first inverted arch anchor 141 is connected to the first steel arch frame 121. The second inverted arch anchor 142 is inserted obliquely downwards into the surrounding rock along the direction from the second steel arch frame 122 to the first steel arch frame 121 and penetrates the fracture zone 11. The upper end of the second inverted arch anchor 142 is connected to the second steel arch frame 122. For example, multiple first inverted arch anchors 141 and multiple second inverted arch anchors 142 are included, and the multiple first inverted arch anchors 141 and multiple second inverted arch anchors 142 are arranged alternately along the transverse direction of the tunnel. See also... Figure 3 Multiple first invert arch anchor bolts 141 are arranged in a horizontal line along the transverse direction of the tunnel, see [reference]. Figure 4Multiple second inverted arch anchors 142 are arranged horizontally along the transverse direction of the tunnel. The number of first inverted arch anchors 141 and second inverted arch anchors 142 can be determined through strength calculations based on the geological conditions at the fault zone 11, and no specific limit is made here. When the tunnel is excavated to the vicinity of the fault zone 11, the first inverted arch anchors 141 can be installed first and connected to the first steel arch frame 121. After the tunnel is excavated to cross the fault zone 11, the second inverted arch anchors 142 are installed and connected to the second steel arch frame 122. Grouting is then injected into the first inverted arch anchors 141 and second inverted arch anchors 142 to connect the surrounding rock on both sides of the lower fault zone 11 of the tunnel 10 to form a composite foundation. Thus, the bearing capacity of the lower surrounding rock can be improved through the cooperation of the first inverted arch anchors 141 and second inverted arch anchors 142, effectively preventing uneven settlement of the lower surrounding rock and improving the support performance.

[0043] In some embodiments, see Figure 3 , Figure 4 Both the first steel arch frame 121 and the second steel arch frame 122 include an upper arch frame section 123 and a lower arch frame section 124 connected together from top to bottom. The upper arch frame section 123 is an arc-shaped structure with an open lower end, and the lower arch frame section 124 is a U-shaped structure with an open upper end. The lower end of the upper arch frame section 123 and the upper end of the lower arch frame section 124 are connected together by bolts.

[0044] To improve the stability of the steel arch frame assembly 12 after construction, see Figure 2 A locking anchor assembly 15, inserted into the surrounding rock, is connected to the steel arch frame assembly 12. The locking anchor assembly 15 includes a first locking anchor 151 and a second locking anchor 152. The first locking anchor 151 is connected to the first steel arch frame 121, and the second locking anchor 152 is connected to the second steel arch frame 122. (See also...) Figure 3 The first anchor bolt 151 comprises two sets, respectively disposed on both sides of the first steel arch frame 121; each set of the first anchor bolt 151 comprises two bolts, respectively connected to the waist and bottom of the first steel arch frame 121. See also Figure 4 The second anchor bolt 152 includes two sets, which are respectively set on both sides of the second steel arch 122; each set of the second anchor bolt 152 includes two bolts, which are respectively connected to the waist and bottom of the second steel arch 122.

[0045] This application embodiment also provides a support method applicable to underground utility tunnel excavation crossing a fault zone, including: when the tunnel is excavated to a first position adjacent to the fault zone 11, constructing a first arch top anchor 131 inserted into the tunnel arch and penetrating the fault zone 11 and a first invert anchor 141 inserted into the tunnel invert and penetrating the fault zone 11 along the tunnel excavation direction; constructing a first locking anchor 151 inserted into the surrounding rock and grouting inside the first locking anchor 151; initially spraying concrete on the tunnel section and constructing a steel mesh; fixing the steel mesh to the first locking anchor 151; then constructing a first steel arch frame 121 and fixing it to the first arch top anchor 131, the first invert anchor 141, and the first locking anchor 151 respectively; after the first steel arch frame 121 is constructed, continuing to excavate the tunnel; when the tunnel... When the tunnel is excavated to the second position after crossing the fault zone 11, the second arch top anchor 132, inserted into the tunnel arch and penetrating the fault zone 11, and the second invert arch anchor 142, inserted into the tunnel invert arch and penetrating the fault zone 11, are constructed in the opposite direction of tunnel excavation. The second locking anchor 152 is then inserted into the surrounding rock and grout is injected into the second locking anchor 152. Initial shotcrete is applied to the tunnel cross section and a steel mesh is installed. The steel mesh is then fixedly connected to the second locking anchor 152. The second steel arch frame 122 is then constructed and fixedly connected to the second arch top anchor 132, the second invert arch anchor 142, and the second locking anchor 152. After the second steel arch frame 122 is completed, the first arch top anchor 131, the first invert arch anchor 141, the second arch top anchor 132, and the second invert arch anchor 142 are simultaneously grouted.

[0046] The support method provided in this application for underground utility tunnels excavated through fracture zones is used to form a composite support structure in the fracture zone area of ​​the tunnel, which improves the support performance when underground utility tunnels are excavated through fracture zones, avoids engineering accidents such as water and mud inrush, excessive deformation of surrounding rock, and face collapse during construction, and improves the safety of construction.

[0047] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of this application and within the spirit and principles of this application shall still fall within the protection scope of the technical solution of this application.

Claims

1. A support structure suitable for underground utility tunnels excavated through fracture zones, characterized in that, The steel arch frame assembly (12) is installed near the fault zone (11) and used to support the tunnel (10). The top of the steel arch frame assembly (12) is connected to an arch top anchor assembly (13) that is inserted obliquely upward along the longitudinal direction of the tunnel into the surrounding rock and penetrates the fault zone (11). The bottom of the steel arch frame assembly (12) is connected to an inverted arch anchor assembly (14) that is inserted obliquely downward along the longitudinal direction of the tunnel into the surrounding rock and penetrates the fault zone (11). The steel arch frame assembly (12) includes a first steel arch frame (121) and a second steel arch frame (122) disposed on both sides of the fracture zone (11). The arch anchor assembly (13) includes a first arch anchor (131) and a second arch anchor (132). The first arch-top anchor (131) is inserted obliquely upward into the surrounding rock along the direction from the first steel arch frame (121) to the second steel arch frame (122) and penetrates the fracture zone (11). The lower end of the first arch-top anchor (131) is connected to the first steel arch frame (121). The second arch-top anchor (132) is inserted obliquely upward into the surrounding rock along the direction from the second steel arch frame (122) to the first steel arch frame (121) and penetrates the fracture zone (11). The lower end of the second arch-top anchor (132) is connected to the second steel arch frame (122). The first arch anchor (131) and the second arch anchor (132) each include multiple ones, and the multiple first arch anchors (131) and multiple second arch anchors (132) are arranged alternately along the transverse direction of the tunnel.

2. The support structure for underground utility tunnels traversing fracture zones as described in claim 1, characterized in that, The inverted arch anchor assembly (14) includes a first inverted arch anchor (141) and a second inverted arch anchor (142). The first inverted arch anchor (141) is inserted obliquely downward into the surrounding rock along the direction from the first steel arch frame (121) to the second steel arch frame (122) and penetrates the fracture zone (11). The upper end of the first inverted arch anchor (141) is connected to the first steel arch frame (121). The second inverted arch anchor (142) is inserted obliquely downward into the surrounding rock along the direction from the second steel arch frame (122) to the first steel arch frame (121) and penetrates the fracture zone (11). The upper end of the second inverted arch anchor (142) is connected to the second steel arch frame (122).

3. The support structure for underground utility tunnels traversing fracture zones as described in claim 2, characterized in that, The first arch anchor (141) and the second arch anchor (142) each include multiple ones, and the multiple first arch anchors (141) and multiple second arch anchors (142) are arranged alternately along the transverse direction of the tunnel.

4. The support structure for underground utility tunnels traversing fracture zones as described in claim 1, characterized in that, Both the first steel arch frame (121) and the second steel arch frame (122) include an upper arch frame section (123) and a lower arch frame section (124) connected together from top to bottom.

5. The support structure for underground utility tunnels traversing fracture zones as described in claim 1, characterized in that, The steel arch frame assembly (12) is connected to a locking anchor assembly (15) inserted into the surrounding rock.

6. The support structure for underground utility tunnels traversing fracture zones as described in claim 5, characterized in that, The locking anchor assembly (15) includes a first locking anchor (151) and a second locking anchor (152). The first locking anchor (151) is connected to the first steel arch (121), and the second locking anchor (152) is connected to the second steel arch (122).

7. A support method suitable for underground utility tunnels excavated through fracture zones, employing the support structure described in any one of claims 1 to 6, characterized in that, include: When the tunnel is excavated to the first position adjacent to the fault zone (11), the first arch top anchor (131) inserted into the tunnel arch and penetrating the fault zone (11) and the first invert arch anchor (141) inserted into the tunnel invert arch and penetrating the fault zone (11) are constructed along the tunnel excavation direction. The first locking foot anchor (151) is inserted into the surrounding rock and grout is injected into the first locking foot anchor (151). The tunnel section is initially sprayed with concrete and a steel mesh is constructed. The steel mesh is fixedly connected to the first locking foot anchor (151). Then, the first steel arch frame (121) is constructed and fixedly connected to the first arch top anchor (131), the first invert arch anchor (141), and the first locking foot anchor (151) respectively. After the first steel arch frame (121) is completed, the tunnel excavation continues. When the tunnel is excavated to the second position after crossing the fault zone (11), the second arch top anchor (132) inserted into the tunnel arch and penetrating the fault zone (11) and the second invert arch anchor (142) inserted into the tunnel invert arch and penetrating the fault zone (11) are constructed in the opposite direction of the tunnel excavation. The second locking foot anchor (152) is constructed and grout is injected into the second locking foot anchor (152). The tunnel section is initially sprayed with concrete and steel mesh is constructed. The steel mesh is fixedly connected to the second locking foot anchor (152). The second steel arch frame (122) is then constructed and fixedly connected to the second arch top anchor (132), the second invert arch anchor (142), and the second locking foot anchor (152). After the second steel arch frame (122) is completed, the first arch top anchor (131), the first inverted arch anchor (141), the second arch top anchor (132), and the second inverted arch anchor (142) are simultaneously grouted.

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