Mountain tunnel construction method using tunnel workstation

Abstract

To provide a mountain tunnel construction method using a tunnel workstation that enables a mountain tunnel to be efficiently constructed by minibench cut method in a highly mechanized manner.SOLUTION: A tunnel workstation 10 includes an upper-stage frame part 11 on which a man cage 17 is provided, a pair of right and left middle-stage frame parts 12 on which an erector 18 is provided, and a pair of right and left lower-stage frame parts 13 on which a drilling machine 16 is provided. A liftable slide deck 15, which is a working scaffold for an operator and can be expanded in a width direction Y of a tunnel, is fitted on a lower surface side of the upper-stage frame part 11. A protection net installing step to install a protection net 30 stretched between holding attachment parts 18c of the right and left erectors 18 above a cage body 17c of the man cage 17 and a deck body 15a of the liftable slide deck 15 is included.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mountain tunnel construction method using a tunnel workstation, and in particular to a mountain tunnel construction method using a tunnel workstation used in a mini-bench cut method, in which the bench length is shortened to 2 to 6 m and excavation is carried out while simultaneously crushing the upper and lower tunnel faces by blasting. [Background technology]

[0002] The bench cut method is known as a tunnel construction method for mountain tunnels (mountain tunnel construction method). The bench cut method is a tunnel construction method in which the tunnel face is divided into an upper section and a lower section, and the upper section is excavated before the lower section. Compared to the full-section method, in which the entire face is excavated at once by blasting or the like, the bench cut method makes it possible to excavate the face in a more stable state, and is therefore widely adopted as a method that can excavate mountain tunnels in a wide range of soil types, from soft rock to hard rock.

[0003] Furthermore, a tunnel workstation (TWS) has also been developed to enable efficient construction of mountain tunnels using the bench cut method through advanced mechanization (see, for example, Patent Document 1).

[0004] The TWS in Patent Document 1 is intended for the short bench cut method, which is primarily used in cases of poor geology and involves excavating a bench length of, for example, 1D (tunnel inner diameter) to 50 m, and includes a first frame that is arranged in the upper section and is formed in a roughly portal shape when viewed from the front, and a second frame that is also formed in a roughly portal shape and is arranged in the lower section and is connected to the rear of the first frame. Furthermore, in the TWS in Patent Document 1, prior to excavating the upper section, a region in front of the upper face and corresponding to the outer periphery of the tunnel cross section is drilled with a drilling machine mounted on the first frame, while a soil improvement material is injected with an injection device to improve the ground, and the lower section is excavated with a second excavating machine such as a backhoe. After that, the upper section is excavated with a first excavating machine such as a boom-type rock drill, and a primary lining is constructed in the lower section. These processes are repeated sequentially to construct the tunnel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-307096 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, in recent years, there has been an increasing adoption of the mini-bench cut method, in which the bench length is shortened, preferably to about 2 to 6 m, and the upper and lower face faces are excavated simultaneously while blasting, for ground that needs to be closed as quickly as possible, such as expansive ground or ground with insufficient bearing capacity.

[0007] The mini-bench cut method is a construction method that can streamline, reduce labor, and speed up construction by consolidating excavation work using blasting on a relatively stable tunnel face, as well as improving work safety and the working environment. However, it is necessary to consider the impact of the short bench length on the stability of the tunnel face and the impact of sudden stress release on the stability of the tunnel. For these reasons, there is a demand for the development of a new tunnel workstation (TWS) with a configuration suitable for implementing the mini-bench cut method, separate from the TWS for the short bench cut method, so that mountain tunnel construction using the mini-bench cut method can be carried out efficiently while achieving a high level of mechanization.

[0008] In addition, when constructing a mountain tunnel using the mini-bench cut method, while maintaining a bench length of, for example, 2 to 6 meters, explosives are charged into blast holes drilled into the upper and lower face faces, and excavation is carried out simultaneously at the upper and lower face faces. The inner wall surface of the tunnel excavated by blasting exposes unstable ground, making it prone to surface collapse. This can affect the work of loading explosives into the blast holes and reduce the efficiency of the work. Therefore, it is necessary to effectively prevent the surface collapse of the ground on the inner wall surface of the tunnel from affecting the work of loading explosives.

[0009] The present invention aims to provide a mountain tunnel construction method using a tunnel workstation that enables efficient construction of mountain tunnels using the mini bench cut method while achieving a high level of mechanization, and that effectively prevents the work of loading explosives from being affected by the collapse of the ground on the inner wall surface of the tunnel. [Means for solving the problem]

[0010] The present invention is a mountain tunnel construction method using a tunnel workstation used in a mini-bench cut method, in which the bench length is shortened to 2 to 6 m and excavation is performed while simultaneously crushing the upper and lower face by blasting. The tunnel workstation is composed of an upper frame section, a pair of left and right middle frame sections and a pair of left and right lower frame sections provided in the lower part of the upper frame section via support members that support the upper frame section from below, and the middle frame sections and the lower frame sections on both the left and right sides in the lower area of ​​the upper frame section. The upper frame section has a gate-shaped front shape as a whole, with a vehicle space between the upper and lower frame sections that allows construction vehicles to pass through. A drilling machine capable of drilling holes in the upper face and inner wall surface of the tunnel is attached to the upper surface of the upper frame section so that it can move in the axial direction of the tunnel and swing up, down, left, and right. A man gauge, which serves as a foothold for workers, is attached to the lower surface of the upper frame section so that it can move in the axial direction of the tunnel and swing up, down, left, and right. A liftable slide deck that can be expanded in the width direction of the tunnel and serves as a scaffolding for construction work is attached so that it can slide in the axial direction of the tunnel and can swing up and down, and each of the middle frame parts is attached with an erector that can move in the axial direction of the tunnel and can swing up and down and left and right, and that grips the support members that will be erected along the inner wall surface of the tunnel after excavation, and each of the lower frame parts is attached with a drilling machine that can drill holes in the face and inner wall surface of the lower part of the tunnel and can swing up and down and left and right, and A traveling device is provided to move the tunnel workstation in the axial direction of the tunnel, and when workers use the gauge body of the man gauge or the deck body of the liftable slide deck as a work foothold to load explosives into each of the blast holes drilled in the upper and lower face faces by the drilling machine body of the boring machine, the ends on both sides are respectively engaged with engaging devices provided on the gripping attachment parts of the left and right erectors via engaging parts, so that a protective net stretched between these left and right gripping attachment parts can be secured.The above object has been achieved by providing a mountain tunnel construction method using a tunnel workstation that includes a protective net installation process that is installed above the gauge body of the man gauge and the deck body of the liftable slide deck.

[0011] The mountain tunnel construction method using the tunnel workstation of the present invention preferably includes a first protective net installation step in which a protective net stretched between the engaging devices provided on the gripping attachment parts of the left and right erectors is installed above the gauge body of the man gauge, and in this first protective net installation step, the gauge body is retracted rearward, and the gripping attachment parts of the pair of erectors are moved so that they protrude forward from the upper frame part and are also moved upward, so that the protective net stretched between the engaging devices on both sides is placed close to the upper face and covers the top part of the inner wall surface of the bench part of the tunnel from below, and then the gauge body of the man gauge is moved forward and placed in the area below the protective net that is placed covering the top part of the inner wall surface of the bench part of the tunnel.

[0012] Furthermore, the mountain tunnel construction method using the tunnel workstation of the present invention preferably includes a second protective net installation process, and in the second protective net installation process, when workers use the deck body of the liftable slide deck as a work foothold to load explosives into each of the blast holes drilled in the upper face by the boring machine body of the boring machine, the protective net stretched between the engaging devices provided on the gripping attachment parts of the left and right erectors is preferably placed above the liftable slide deck.

[0013] Furthermore, in the mountain tunnel construction method using the tunnel workstation of the present invention, in the second protective net installation process, the deck body is preferably moved backward without being widened, and the gripping attachment parts of the pair of erectors are moved so that they protrude forward from the upper frame part and are moved upward, so that the protective net stretched between the engaging devices on both sides is placed close to the upper face and covers the upper part of the inner wall surface of the bench part of the tunnel from below, and then the deck body is moved forward and positioned in the area below the protective net that is placed covering the upper part of the inner wall surface of the bench part of the tunnel, and the deck body is widened.

[0014] Furthermore, the mountain tunnel construction method using the tunnel workstation of the present invention includes a third protective net installation process, and in this third protective net installation process, when workers use the expanded deck body of the liftable slide deck or the bottom part of the tunnel as a work foothold to load explosives into each of the blast holes drilled in the lower face by the boring machine drilling machine body, it is preferable that the protective net, which is suspended and stretched between the left and right gripping attachment parts, is installed in the middle part of the height direction of the bench part of the tunnel by having the ends 30a on both sides each engaged with a hanging engaging device provided on the gripping attachment part of the left and right erectors via an engaging part.

[0015] Furthermore, the mountain tunnel construction method using the tunnel workstation of the present invention preferably includes a fourth protective net installation process in which, when workers use the expanded deck body of the liftable slide deck or the bottom part of the tunnel as a work foothold to load explosives into each blast hole drilled in the face of the lower stage by the boring machine body of the lower stage boring machine, the protective net stretched between the engaging devices provided on the gripping attachment parts of the left and right erectors is installed above the expanded deck body of the liftable slide deck or the bottom part of the tunnel.

[0016] In the mountain tunnel construction method using the tunnel workstation of the present invention, in the fourth protective net installation step, preferably, the deck body is retracted rearward without being widened, and the gripping attachment parts of the pair of erectors are extended forward from the upper frame part and moved to a position in front of the face of the lower stage, and are also moved to a position above the height position of the bench part of the tunnel, thereby bringing the protective net stretched between the engaging devices on both sides close to a position in front of the face of the lower stage, It is preferable that after the liftable slide deck is arranged in a state covering from below the upper half of the inner wall surface in front of the bench portion of the tunnel, the deck body of the liftable slide deck is moved forward and placed in the area below the protective net arranged to cover the upper half of the inner wall surface in front of the bench portion of the tunnel, and the deck body is widened so that accumulating work can be carried out from the widened work scaffolding, or the bottom part of the tunnel in front of the lower face can be used as a work scaffolding to carry out accumulating work. [Effects of the Invention]

[0017] According to the mountain tunnel construction method using the tunnel workstation of the present invention, it is possible to efficiently carry out the construction of mountain tunnels using the mini bench cut method while achieving a high level of mechanization, and it is also possible to effectively avoid the impact on the work of loading explosives due to the skin of the ground on the inner wall surface of the tunnel. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 illustrates a tunnel workstation for a mini bench cut method used in a mountain tunnel construction method according to a preferred embodiment of the present invention, where (a) is a schematic side view during drilling by a boring machine, and (b) is a schematic cross-sectional view along AA in (a). [Figure 2]This is a schematic side view illustrating a tunnel workstation for a mini bench cut method used in a mountain tunnel construction method according to a preferred embodiment of the present invention, showing the erection of support members using an erector. [Figure 3] (a) is a schematic side view of a tunnel workstation illustrating the man cage and liftable slide deck that serve as a foothold for workers, and (b) is a schematic top view of the upper frame section illustrating the man cage. [Figure 4] (a) is a schematic side view illustrating a liftable slide deck attached to the underside of the upper frame section, (b) is a schematic bottom view of the upper frame section viewed from below, and (c) is a schematic front view of (a) viewed from the left side. [Figure 5] (a) is a schematic side view of the liftable slide deck, illustrating the state in which the deck body is extended from the upper frame portion, (b) is a schematic bottom view of the state in which the deck body is expanded, and (c) is a schematic front view of (a) viewed from the left side. [Figure 6] 1(a) and 1(b) are schematic side views illustrating a construction method using a tunnel workstation for the mini bench cut construction method. [Figure 7] 10(a) and 10(b) are a schematic cross-sectional view and a schematic side view illustrating a state in which a protective net is arranged to cover the top end portion of the inner peripheral wall surface. [Figure 8] 10(a) and 10(b) are a schematic cross-sectional view and a schematic side view illustrating a state in which a protective net is disposed to cover the upper part of the inner peripheral wall surface. [Figure 9] 10(a) and 10(b) are a schematic cross-sectional view and a schematic side view illustrating a situation in which a protective net is installed in the middle part of a tunnel in the height direction. [Figure 10] 10(a) and 10(b) are a schematic cross-sectional view and a schematic side view illustrating a situation in which a protective net is installed in the middle part of a tunnel in the height direction. [Figure 11](a) to (c) are schematic side views and schematic top views illustrating the first erection step of erecting upper-stage divided support members in the mini bench cut method in mountain tunnel construction according to a preferred embodiment of the present invention, and (d) is a schematic side view illustrating the first joining step of joining the upper-stage divided support members. [Figure 12] (a) to (c) are schematic side views and schematic top views illustrating the second erection process of erecting a lower divided support member in the mini bench cut method in a mountain tunnel construction method according to a preferred embodiment of the present invention, and (d) is a schematic side view illustrating the second joining process of joining a lower divided support member to an upper divided support member. [Figure 13] 1(a) is a schematic side view illustrating the upper rock bolt fixing process and the lower rock bolt fixing process in a mini bench cut method for mountain tunnel construction according to a preferred embodiment of the present invention, and FIG. 1(b) is a schematic cross-sectional view. [Figure 14] This is a schematic side view illustrating the situation in which blast holes are drilled into the face using multiple boring machines in a full cross-section construction method for mountain tunnel construction according to a preferred embodiment of the present invention. [Figure 15] This is a simplified side view illustrating the situation in which various operations are performed on the face and inner wall surface using a man gauge and a liftable slide deck as work scaffolding in a full cross-section construction method for mountain tunnel construction according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] A mountain tunneling method using a tunnel workstation according to a preferred embodiment of the present invention can be implemented using a tunnel workstation 10 for the mini-bench cut method, as shown in Figures 1(a), 1(b), and 2. The tunnel workstation 10 shown in Figures 1(a), 1(b), and 2 is used to form a mountain tunnel 50, preferably a mountain tunnel 50 having a hollow cross-section with a preferably horseshoe shape and a height of approximately 8 m and a width of approximately 9 m, using the mini-bench cut method, in which an upper face 51 and a lower face 52 are excavated simultaneously by blasting, with a short bench length of 2 to 6 m. The mountain tunneling method of this embodiment enables efficient construction of mountain tunnels using the mini-bench cut method while achieving a high level of mechanization using the tunnel workstation 10, and effectively prevents the collapse of the natural ground on the inner wall of the tunnel from affecting the explosive charging work.

[0020] In other words, the tunnel workstation 10 for the mini bench cut method used in the mountain tunnel construction method of this embodiment has been developed in the past to enable the construction of mountain tunnels to be carried out efficiently using the bench cut method. However, while various tunnel workstations for such conventional bench cut methods are intended for the short bench cut method, in which the bench length is, for example, about 1D to 50m, and cannot be applied as is to the mini bench cut method, which has seen increasing demand in recent years and is a method in which the bench length is shortened to, for example, about 2 to 6m and excavation is carried out while blasting is carried out simultaneously at the upper section face 51 and the lower section face 52. Therefore, it has been newly developed as a tunnel workstation suitable for construction using the mini bench cut method.

[0021] The tunnel workstation 10 for the mini bench cut method is a tunnel workstation used in the mini bench cut method, a mountain tunnel construction method in which the bench length is shortened to 2 to 6 m and excavation is performed while the upper face 51 and the lower face 52 can be simultaneously crushed by blasting.As shown in Figures 1(a), (b) and 2, it is composed of an upper frame section 11, a pair of left and right middle frame sections 12 and a pair of left and right lower frame sections 13 provided in the lower part of the upper frame section 11 via support members 14a, 14b that support both side parts of the upper frame section 11 in the width direction Y of the tunnel 50 from below, and has an overall gate-shaped front shape that holds a vehicle space 20 that allows construction vehicles to pass between the middle frame sections 12 and the lower frame sections 13 on both sides in the lower area of ​​the upper frame section 11.

[0022] A drilling machine (upper-stage drilling machine) 16 capable of drilling holes in the upper tunnel face 51 and inner wall surface 53 is attached to the upper frame section 11 so as to be slidable in the axial direction X of the tunnel and swivelable up, down, left, and right. A man gauge 17, which serves as a foothold for workers and has an extendable boom section 17b (see Figures 3(a) and 3(b)), is attached to the upper frame section 11 so as to be slidable in the axial direction X of the tunnel 50 and swivelable up, down, left, and right. An erector 18, which has an extendable boom section 18b (see Figure 2) and grips support members 27 (divided support members 27a, 27b) that will be erected along the inner wall surface 53 of the tunnel after excavation, is attached to each middle frame section 12 so as to be slidable in the axial direction X of the tunnel and swivelable up, down, left, and right. A drilling machine (lower drilling machine) 16' capable of drilling holes in the lower tunnel face 52 and inner peripheral wall surface 53 is attached to each lower frame section 13 so that it can swing up, down, left, and right, and traveling devices 19a, 19b are also provided for moving the tunnel workstation 10 in the axial direction X of the tunnel 50. The upper frame section 11 and each middle frame section 12 are arranged so that their tip ends protrude further toward the face faces 51, 52 in the axial direction X of the tunnel 50 than the tip ends of the respective lower frame sections 13.

[0023] In addition, in this embodiment, the support members 14a, 14b that support both side portions of the upper frame portion 11 in the width direction Y of the tunnel 50 from below preferably each include at least two (three in this embodiment) main support members 14a, 14a' arranged continuously between the upper frame portion 11, the middle frame portion 12 and the lower frame portion 13, and one sub-support member 14b arranged between the upper frame portion 11 and the middle frame portion 12 in a portion that protrudes toward the face faces 51, 52 in the axial direction X of the tunnel 50 beyond the tip of the lower frame portion 13 (see Figure 1(a)).

[0024] Furthermore, in this embodiment, preferably, an interference prevention notch 12c is formed on the lower side of the tip portion of the middle frame portion 12 that protrudes toward the face surfaces 51, 52 in the axial direction X of the tunnel 50 more than the lower frame portion 13, in order to avoid interference with the oscillating lower stage drilling machine 16' attached to the lower frame portion 13 (see Figure 1(a)).

[0025] Furthermore, in this embodiment, a liftable slide deck 15, which is preferably supported on the underside of the upper frame portion 11 and can be expanded in the width direction Y of the tunnel 50, which serves as a foothold for workers, is attached so that it can slide in the axial direction X of the tunnel 50 and swing up and down (see Figures 5(a) to (c)).

[0026] In this embodiment, the upper frame 11 constituting the tunnel workstation 10 is formed by assembling steel members such as H-shaped steel beams into a rectangular frame shape, with a length of approximately 14 m in the axial direction X of the tunnel 50 and a width of approximately 7.7 m in the transverse direction Y perpendicular to the axial direction X. The frame has an upper surface 11a, on which plate members such as steel plates are laid. A central guide rail 11b is attached to the center of the upper surface 11a, extending in the axial direction X of the tunnel 50, for sliding the base 17a of a known man gauge 17 (see FIGS. 1(b), 3(a), and 3(b)). Side guide rails 11c, which allow sliding of the base 16a of a known upper-stage drilling machine (upper-stage drilling machine) 16, are attached to both sides of the central guide rail 11b, extending in the axial direction X of the tunnel 50 and parallel to the central guide rail 11b (see FIG. 1(b)).

[0027] The middle frame section 12, which constitutes the tunnel workstation 10 together with the upper frame section 11, is formed by assembling steel members such as H-shaped steel beams into a rectangular framework upper surface section 12a (see FIG. 1(a)) with dimensions of, for example, about 13 m in the axial direction X of the tunnel 50 and about 2.1 m in width in the transverse direction Y perpendicular to the axial direction X, and by laying steel plate members such as steel plates on the upper surface section 12a. The middle frame sections 12 are provided as a pair below each of the side edge sections on both sides of the upper frame section 11, spaced apart, for example, by about 2.3 m from the upper frame section 11 (see FIGS. 1(b) and 11(b)). At the inner part of each middle frame part 12 on the vehicle space 20 side, the above-mentioned main support member 14a and sub-support member 14b are erected at a predetermined interval in the axial direction X of the tunnel 50, and at the outer part, a known erector guide rail part 12b that slides the base part 18a of the erector 18 is attached by extending it in the axial direction X of the tunnel 50 while avoiding interference with the support members 14a, 14b.

[0028] The lower frame section 13, which constitutes the tunnel workstation 10 together with the upper frame section 11 and the middle frame section 12, is formed by assembling steel members such as angle irons into a rectangular framework having a length of about 13 m in the axial direction X of the tunnel 50 and a width of about 1 m in the lateral direction Y perpendicular to the axial direction X, and is formed by laying plate members such as steel plates on an upper surface section 13a (see FIG. 1(a)). A pair of lower frame sections 13 are provided below each middle frame section 12, spaced apart from each other by about 1.6 m (see FIG. 1(b)). Each lower frame section 13 is provided with lower main support members 14a' arranged vertically continuous with the main support members 14a erected from the middle frame section 12, and is erected at three locations at predetermined intervals in the axial direction X of the tunnel 50 (see Figure 1(a)), with its lower end supported by the traveling equipment 19a, 19b (see Figure 4(a)).

[0029] In this embodiment, the pair of lower frame sections 13 on both sides are arranged to extend rearward, opposite the working faces 51, 52, from the position of the lower main support member 14a', one of the three lower main support members 14a', which is arranged at the tip end closest to the working faces 51, 52 in the axial direction X of the tunnel 50. As a result, as described above, the tip ends of the upper frame section 11 and each of the middle frame sections 12 are arranged to protrude by a bench length of, for example, about 2 to 6 meters toward the working faces 51, 52 in the axial direction X of the tunnel 50 beyond the tip end of each lower frame section 13. A well-known lower drilling machine 16' is fixed and attached to the tip end of each lower frame section 13 in a manner that allows it to extend and retract and to swing up, down, left, and right.

[0030] In this embodiment, the three traveling devices 19a, 19b provided on each lower frame 13, supporting the lower end of the lower main support member 14a', comprise a pair of main traveling devices 19a located at the leading and trailing ends of the tunnel 50 in the axial direction X, and a secondary traveling device 19b located in the middle between them. Each main traveling device 19a is equipped with a stopper and outrigger 21 (see FIGS. 1(b) and 4(c)). This allows the tunnel workstation 10 to move and stop along traveling rails 55 extending in the axial direction X of the tunnel 50 and laid on the bottom surface 54 to a predetermined stopping position, and to be firmly maintained in the stopped position. Furthermore, by further extending the outriggers as needed, the tunnel workstation 10 can be lifted up, and the traveling rails 55 can be re-laid, for example, by pulling them out in the axial direction X, i.e., the extending direction. A work deck section 22 that can be accessed by workers can be provided on the outside of each stopper and outrigger section 21 (see Figure 1 (b)), and workers can use the work deck section 22 as a foothold to perform various types of work.

[0031] The drilling machine (upper-stage drilling machine) 16 attached to the upper-stage frame 11 can be a variety of drilling machines, such as those attached to a drill jumbo, known for drilling blast holes to be charged with explosives when blasting the tunnel face or for drilling anchor holes to secure rock bolts on the periphery of a tunnel, with appropriate modifications. In this embodiment, the upper-stage drilling machine 16 includes a base 16a that can slide along the side guide rails 11c in the axial direction X of the tunnel, a preferably extendable boom 16b that is connected to the tip of the base 16a via a joint so as to be rotatable up, down, left, and right, and a drilling machine main body 16c that is connected to the tip of the boom 16b via a joint so as to be rotatable up, down, left, and right. As a result, the drilling machine body 16c of the upper-stage drilling machine 16 is attached to the upper-stage frame section 11 so that it can slide in the axial direction X of the tunnel and swing up, down, left, and right while projecting from the upper-stage frame section 11 toward the tunnel face 51. As a result, the upper-stage drilling machine 16 can be moved forward from a state where it is stored above the upper-stage frame section 11 (see Figures 3(b), 6(a), and (b)), preferably by operating the driver's cab 16d (see Figure 1(a)) provided on the base section 16a, to adjust the projecting position of the drilling machine body 16c from the upper-stage frame section 11 and change the direction of the drilling machine body 16c, thereby accurately drilling blast holes to be charged with explosives and fixing holes to fix rock bolts at appropriate positions on the upper-stage tunnel face 51 and inner peripheral wall surface 53.

[0032] 3(a) and 3(b), the man gauge 17 attached to the upper frame 11 can be a known work gauge with appropriate modifications, and can be used, for example, as a gauge attached to various construction vehicles for high-altitude work. In this embodiment, the man gauge 17 includes a base 17a that is slidable in the axial direction X of the tunnel 50 along the central guide rail 11b, an extendable boom 17b that is joined to the tip of the base 17a via a joint so that it can rotate up, down, left, and right, and a gauge body 17c that is attached to the tip of the boom 17b via a joint. As a result, the gauge body 17c of the man gauge 17 is attached to the upper frame 11 so that it can slide in the axial direction X of the tunnel 50 and swing up, down, left, and right while extending out from the upper frame 11 toward the working face 51. This also allows the man gauge 17 to be stored above the upper frame section 11 (see Figures 6(a) and (b)), and the base section 17a to be advanced to adjust the position of its projection from the upper frame section 11, while also changing the angle of the boom section 17b, so that the gauge body 17c is positioned preferably close to the upper working face 51 or the inner wall surface 53.This allows the gauge body 17c to be used as a work platform to load explosives into the blast holes described below, to secure rock bolts 59 in the anchorage holes, or to join the upper divided support members 27a erected in the upper section as a single unit (see Figure 11(d)).

[0033] The erectors 18 attached to each of the pair of middle frame sections 12 on both sides can be used with appropriate modifications to various gripping devices known as devices for erecting steel support members, preferably H-shaped steel, along the inner circumferential surface of a tunnel, as shown in Fig. 2. In this embodiment, the erector 18 includes a base section 18a that can slide in the axial direction X of the tunnel 50 along the erector guide rail section 12b (see Figs. 1(b) and 11(b)), an extendable boom section 18b joined to the tip of the base section 18a via a joint section so as to be rotatable up, down, left, and right, and a gripping attachment section 18c joined to the tip of the boom section 18b via a joint section so as to be rotatable up, down, left, and right. As a result, the boom section 18b and the gripping attachment section 18c of the erector 18 are attached to the middle-stage frame section 12 so as to be slidable in the axial direction X of the tunnel 50 and so as to be swingable up, down, left, and right while projecting from the middle-stage frame section 12 toward the working faces 51 and 52. As a result, the erector 18 can be moved forward from a state in which it is stored above the middle-stage frame section 12 (see FIGS. 1(a), 6(a), and (b)), preferably by operating the driver's cab provided on the base section 18a, to adjust the projecting position of the gripping attachment section 18c from the middle-stage frame section 12, and while changing its direction, erect, for example, an upper-stage divided support member 27a gripped by the gripping attachment section 18c to a predetermined position in front of the upper working face 51 newly formed by blasting (see FIGS. 2(a) and 11(a) to (d)). Furthermore, for example, the lower divided support member 27b grasped by the grasping attachment portion 18c can be erected continuously below the upper divided support member 27a that has been fixed in advance at a predetermined position just before the lower face 52 newly formed by blasting (see Figures 12(a) to (d)).

[0034] The drilling machines (lower-stage drilling machines) 16' attached to the pair of lower-stage frame members 13 on both sides, like the upper-stage drilling machine 16, can be used with various drilling machines, known for drilling blast holes to be charged with explosives when blasting the tunnel face or for drilling anchor holes to secure rock bolts on the periphery of a tunnel, with appropriate modifications. In this embodiment, as shown in FIG. 1(a), the lower-stage drilling machine 16' includes a preferably extendable boom section 16b connected to the tip of each lower-stage frame member 13 on the face 52 side via a joint section so as to be rotatable up, down, left, and right, and a drilling machine main body 16c connected to the tip of the boom section 16b via a joint section so as to be rotatable up, down, left, and right. As a result, the drilling machine main body 16c of the lower-stage drilling machine 16' is attached to the lower-stage frame member 13 so as to be able to swing up, down, left, and right, without sliding in the axial direction X of the tunnel 50, while extending from the lower-stage frame member 13. In addition, by operating the working deck section 22 (see Figure 1 (b)), which is preferably supported and attached to the stopper and outrigger section 21 of the main traveling equipment 19a provided on the lower frame section 13, the lower stage drilling machine 16' can adjust the protruding position of the drilling machine main body 16c from the lower frame section 13 and, by changing the direction of the drilling machine main body 16c, accurately drill blasting holes into which explosives are loaded and fixing holes into which rock bolts 59 are fixed at appropriate positions on the lower face 52 and inner wall surface 53.

[0035] In this embodiment, as described above, the lower-stage drilling machine 16' is attached so as to be rotatable up, down, left, and right, extending from the tip of each lower-stage frame section 13 without sliding in the axial direction X of the tunnel 50, and the pair of middle-stage frame sections 12 are positioned so that their tips protrude further toward the tunnel face 51, 52 in the axial direction X than the tips of the respective lower-stage frame sections 13. This makes it easy for the boom section 16b and the drilling machine body 16c of the lower-stage drilling machine 16' to interfere with the tip portion of the middle-stage frame section 12, for example, made of H-shaped steel, particularly when swinging upward. In this embodiment, as shown in FIG. 1(a), an interference-preventing notch 12c is formed in the middle-stage frame section 12 below the tip portion, preferably made of H-shaped steel, of the middle-stage frame section 12, which protrudes further toward the tunnel face 51, 52 in the axial direction X than the lower-stage frame section 13. This makes it possible to effectively avoid interference between the boom section 16b and the drilling machine body 16c of the swivelable lower stage drilling machine 16' attached to the lower stage frame section 13 and the middle stage frame section 12 when they rotate upward.

[0036] Furthermore, in this embodiment, as described above, the liftable slide deck 15, which is expandable in the width direction Y of the tunnel 50 and serves as a foothold for workers, is preferably supported on the lower surface side of the upper frame portion 11 and is attached so as to be slidable in the axial direction X of the tunnel 50 and swingable up and down (see FIG. 3(a)). That is, in this embodiment, as shown in FIGS. 4(a) to 4(c) and 5(a) to 5(c), two sets of deck guide rails 23, each consisting of a pair of rail members 23a, are joined to the lower surface side of the upper frame portion 11 and attached so as to extend parallel to the axial direction X of the tunnel 50. Two liftable slide decks 15 are provided, each supported by these two sets of deck guide rails 23, with deck bodies 15a expandable in the width direction Y of the tunnel 50 slidable in the axial direction X of the tunnel 50 and swingable up and down.

[0037] Here, the two liftable slide decks 15 have a known configuration, including a slide base portion 15b that is supported by a pair of deck guide rails 23 and can slide along the deck guide rails 23 in the axial direction X of the tunnel 50, a ladder-shaped pivot arm portion 15c that is connected via a joint to the tip portion of the slide base portion 15b on the face 51, 52 side so as to be able to swing up and down, and a deck main body 15a that is connected and supported to the tip portion of the pivot arm portion 15c so as to be able to pivot. The deck main body 15a of each liftable slide deck 15 has a horizontally elongated rectangular planar shape with a vertical width of about 1.5 m and a horizontal width of about 3.0 m (see FIG. 4(b)). As shown in Figures 5(b) and (c), the deck body 15a is configured to include a lower scaffolding board 15d connected and supported to the tip of the rotating arm section 15c, and an upper scaffolding board 15e arranged on top of the upper surface of the lower scaffolding board 15d so as to be slidable in the width direction Y. Fall prevention handrails 15f are attached to the outer peripheral edges of each of the lower scaffolding board 15d and the upper scaffolding board 15e in an upright position so as to be foldable (see Figures 5(a) and (c)).

[0038] Each liftable slide deck 15 can be stored in a compact state on the underside of the upper frame portion 11 by folding the fall prevention handrail 15f and placing the upper scaffolding board 15e on top of the lower scaffolding board 15d, and then moving the deck main body 15a together with the slide base portion 15b and the ladder-shaped pivot arm portion 15c along the deck guide rail 23 to the rear side in the axial direction X of the tunnel 50 (see Figures 4(a) to (c)). Furthermore, each liftable slide deck 15 is compactly stored on the underside of the upper frame portion 11, and as needed, the slide base portion 15b is pushed out together with the pivoting arm portion 15c and the deck main body 15a toward the face 51, 52 in the axial direction X of the tunnel 50, and then the pivoting arm portion 15c is rotated downward to lower the deck main body portion 15a to the vicinity of the bottom portion 54 or bench portion 56 of the tunnel 50, and preferably the upper scaffolding board 15e is slid in the width direction Y along the upper surface of the lower scaffolding board 15d, thereby widening the scaffolding portion of the deck main body 15a in the width direction Y and erecting the folded fall prevention handrail 15f. This makes it possible to form a work platform for workers that has a length equivalent to the width direction Y of the tunnel 50, in which the upper scaffolding boards 15e of the deck main body 15a of a pair of liftable slide decks 15 and the lower scaffolding boards 15d that have been moved to the side of them are connected as a single unit (see Figures 5(b) and (c)).

[0039] In addition, in this embodiment, the ladder-shaped pivoting arm portion 15c, which connects and supports the deck main body 15a at its tip, has its base end connected to the end of the sliding base portion 15b on the working face 51, 52 side via a joint portion so that it can swivel up and down.Therefore, by operating the sliding base portion 15b, for example, the deck main body 15a can be swiveled up and down, preferably while being widened in the width direction Y, and the pivoting arm portion 15c can be moved back and forth appropriately together with the sliding base portion 15b in the axial direction X of the tunnel 50 as necessary, so that the deck main body 15a, which serves as a work platform, can be positioned close to these working faces 51, 52 at a predetermined height position on each of the upper working face 51 and the lower working face 52. This also enables workers to smoothly perform tasks such as loading explosives into the drilled blast holes described below, fixing rock bolts into the drilled fixing holes described below, and bolting together the erected split support members 27a and 27b to form a single unit, as described below.

[0040] To perform mountain tunnel construction using the bench-cut method using the mini-bench-cut tunnel workstation 10 configured as described above, as shown in Figures 6(a) and 6(b), the tunnel workstation 10 is mounted so that it can travel on traveling rails 55 laid in the axial direction X on the bottom surface 54 of the tunnel 50. The upper-level drilling machine 16 is placed above the upper-level frame 11, and the erector 18 is placed above the middle-level frame 12. The tunnel workstation 10 is then moved to a predetermined position adjacent to a bench section 56 with a bench length of approximately 2 to 6 meters, where an upper-level face 51 and a lower-level face 52 were previously excavated during the previous blasting span, by opening the stoppers and outriggers 21. Once the tunnel workstation 10 has been moved to the predetermined position adjacent to the bench section 56, the stoppers and outriggers 21 are activated to stably install the tunnel workstation 10 in the predetermined position.

[0041] Once the tunnel workstation 10 has been installed at a predetermined position adjacent to the bench portion 56, as shown in Figure 1, the drilling machine body 16c of the upper stage drilling machine 16, which extends from the upper frame portion 11 toward the upper face 51, drills and forms multiple blast holes at predetermined positions on the upper face 51 of the tunnel 50 and the inner wall surface 53 surrounding the face 51, into which explosives will be loaded when blasting, and the drilling machine body 16c of the lower stage drilling machine 16', which is attached to the tip portion of the lower frame portion 13, drills and forms multiple blast holes at predetermined positions on the lower face 52 and the inner wall surface 53 surrounding the face 52, into which explosives will be loaded when blasting. Thereafter, as shown in Figure 3(a), the gauge body 17c of the man gauge 17, which extends from the upper frame portion 11 toward the upper working face 51, and the widened deck body 15a of the liftable slide deck 15, which extends toward the upper and lower working faces 51, 52, are used as work platforms to load explosives into each of the blast holes that have been created.

[0042] In a mountain tunnel construction method using a tunnel workstation according to a preferred embodiment of the present invention, when workers load each of the blast holes that have been created with explosives, they use a pair of erectors 18 attached to the middle frame sections 12 on both sides, preferably with a locking jig 18d interposed between the gripping attachment sections 18c of the pair of erectors 18, and use a protective net 30 that is tensioned and secured to each of the ends on both sides, thereby effectively preventing the work of loading explosives from being affected by a fall in the ground on the inner wall surface 53 of the tunnel, for example at the bench section 56.

[0043] That is, in a mountain tunnel construction method using a tunnel workstation according to a preferred embodiment of the present invention, when workers use the gauge body 17c of the man gauge 17 or the deck body 15a of the liftable slide deck 15 as a work foothold to load explosives into each of the blast holes drilled in the upper face 51 or the lower face 52 by, for example, the drilling machine body 16c of the upper stage drilling machine 16 or the lower stage drilling machine 16' (see Figure 1(a)), the protective net 30 is preferably installed above the gauge body 17c of the man gauge 17 or the deck body 15a of the liftable slide deck 15 by fastening both ends of the net to the fastening devices 18d provided on the gripping attachment parts 18c of the left and right erectors 18 via the fastening parts.

[0044] For example, as shown in Figures 7(a) and (b), in the first protective net installation process in which the protective net 30 stretched between the engaging devices 18d provided on the gripping attachment parts 18c of the left and right erectors 18 is installed above the gauge body 17c of the man gauge 17, preferably with the gauge body 17c of the man gauge 17 retracted rearward, the gripping attachment parts 18c of the pair of erectors 18 are moved so that they protrude forward from the upper frame part 11 and are also moved upward, so that the protective net 30 stretched between the engaging devices 18d on both sides is placed close to the upper cutting face 51 and covers the top portion 53a of the inner wall surface 53 of the bench portion 56 of the tunnel 50 from below. Thereafter, the gauge body 17c of the man gauge 17 is moved forward and placed in the area below the protective net 30 arranged to cover the top portion 53a of the inner wall surface 53 in the bench portion 56 of the tunnel 50, so that the loading work can be carried out.

[0045] As a result, when working above the upper working face 51 using the gauge body 17c of the man gauge 17 as a work foothold, even if the ground at the top portion 53a of the inner wall surface 53 at the bench portion 56 of the tunnel 50 falls off, the fallen rock debris and the like can be caught by the stretched protective net 30, preventing it from affecting the work of the worker on the gauge body 17c.

[0046] Furthermore, as shown in Figures 8(a) and (b), for example, when workers use the expanded deck body 15a of the liftable slide deck 15 as a work foothold to load explosives into each blast hole drilled in the upper working face 51 by the drilling machine body 16c of the upper stage drilling machine 16 (see Figure 1(a)), a second protective net installation process can be included in which a protective net 30 stretched between the engaging devices 18d provided on the gripping attachment parts 18c of the left and right erectors 18 is placed above the expanded deck body 15a of the liftable slide deck 15.

[0047] In the second protective net installation process, in which the protective net 30 stretched between the engaging members 18d of the gripping attachment portions 18c of the left and right erectors 18 is installed above the expanded deck main body 15a of the liftable slide deck 15, preferably the deck main body 15a is moved backward without being widened, and the gripping attachment portions 18c of the pair of erectors 18 are moved so that they protrude forward from the upper frame portion 11 and are also moved upward, so that the protective net 30 stretched between the engaging members 18d on both sides is installed close to the upper cutting face 51, covering the upper part of the inner wall surface 53 of the bench portion 56 of the tunnel 50 from below. Thereafter, the deck body 15a of the liftable slide deck 15 is moved forward and placed in the area below the protective net 30 arranged to cover the upper part of the inner wall surface 53 in the bench portion 56 of the tunnel 50, and the deck body 15a is widened so that the loading work can be carried out from the widened work scaffolding.

[0048] As a result, even if the ground on the upper inner wall surface 53 of the bench portion 56 of the tunnel 50 falls off when working on the upper face 51 using the widened deck main body 15a of the liftable slide deck 15 as a work foothold, the fallen rock debris and the like can be caught by the stretched protective net 30, preventing it from affecting the work of the workers on the widened deck main body 15a.

[0049] Furthermore, as shown in Figures 9(a) and (b), for example, when workers use the expanded deck body 15a of the liftable slide deck 15 or the bottom part 54 of the tunnel 50 as a work foothold to load explosives into each blast hole drilled in the lower working face 52 by the drilling machine body 16c of the lower stage drilling machine 16' (see Figure 1(a)), a third protective net installation process can be included in which the protective net 30, which is suspended and stretched between the left and right gripping attachment parts 18c, is installed in the vertical middle part of the bench part 56 of the tunnel 50 by each of the end parts 30a on both sides being engaged with the hanging engaging devices 18d provided on the gripping attachment parts 18c of the left and right erectors 18 via the engaging parts.

[0050] As a result, even if the ground on the inner wall surface 53 of the upper half of the bench portion 56 of the tunnel 50 falls when working on the lower face 52 using the widened deck main body 15a of the liftable slide deck 15 or the bottom surface 54 of the tunnel 50 as a work foothold, the fallen rock debris and the like can be caught by the stretched protective net 30, preventing the work of workers on the widened deck main body 15a or the bottom surface 54 from being affected.

[0051] Furthermore, as shown in Figures 10(a) and (b), for example, when workers use the expanded deck body 15a of the liftable slide deck 15 or the bottom surface 54 of the tunnel 50 as a work foothold to load explosives into each blast hole drilled in the lower working face 52 by the drilling machine body 16c of the lower stage drilling machine 16' (see Figure 1(a)), a fourth protective net installation process can be included in which the protective net 30 stretched between the engaging devices 18d provided on the gripping attachment parts 18c of the left and right erectors 18 is placed above the expanded deck body 15a of the liftable slide deck 15 or the bottom surface 54 of the tunnel 50.

[0052] In the fourth protective net installation process, in which the protective net 30 stretched between the engaging members 18d of the gripping attachment portions 18c of the left and right erectors 18 is installed above the expanded deck main body 15a of the liftable slide deck 15 or the bottom surface 54 of the tunnel 50, preferably the deck main body 15a is moved backward without being widened, and the gripping attachment portions 18c of the pair of erectors 18 are made to extend forward from the upper frame portion 11 and moved to a position in front of the lower cutting face 52 and to a position higher than the height position of the tunnel bench portion 56, so that the protective net 30 stretched between the engaging members 18d on both sides is placed close to a position in front of the lower cutting face 52, covering the upper half of the inner wall surface 53 in front of the tunnel bench portion 56 from below. Thereafter, the deck body 15a of the liftable slide deck 15 is moved forward and placed in the area below the protective net 30 arranged to cover the upper half of the inner wall surface 53 in front of the bench portion 56 of the tunnel 50, and the deck body 15a is widened so that the loading work can be carried out from the widened work scaffolding, or the bottom portion 54 of the tunnel 50 in front of the lower working face 52 can be used as a work scaffolding to carry out the loading work.

[0053] As a result, even if the ground on the inner wall surface 53 of the upper half of the tunnel 50 just before the bench portion 56 falls off when working on the lower face 52 using the widened deck main body 15a of the liftable slide deck 15 or the bottom portion 54 of the tunnel 50 as a work foothold, the fallen rock debris and the like can be caught by the stretched protective net 30, preventing the work of workers on the widened deck main body 15a or the bottom portion 54 of the tunnel 50 from being affected.

[0054] The protective net 30 of this embodiment is formed by connecting a plurality of unit protective nets (not shown) in series along the tunnel width direction Y. The unit protective nets have known connecting fittings attached to their metal frames, allowing any number of units to be connected in series along the tunnel width direction Y. This makes the length of the protective net 30 adjustable in the tunnel width direction Y, allowing the length to be adjusted according to the distance in the tunnel width direction Y of the tunnel 50 at the height position where the protective net 30 is stretched. Therefore, according to the mountain tunnel construction method of this embodiment, the protective net 30 can be stretched above the work area over the entire area of ​​the work area in the tunnel width direction Y. This allows the protective net 30 to more reliably catch rock debris and the like that falls off the work surface, thereby further minimizing the impact of such debris on the work of workers.

[0055] Well-known locking jigs such as shackles and hooks are used for the locking parts provided at the ends on both sides of the protective net 30. Furthermore, for the locking devices 18d provided on the gripping attachment parts 18c of the left and right erectors 18, for example, rod-shaped metal fittings or hanging rings arranged horizontally along the tunnel axis direction X and capable of locking the locking parts provided at the ends on both sides of the protective net 30 can be used.

[0056] After the multiple blast holes drilled at predetermined positions on the upper face 51 and the lower face 52 have been charged with explosives as described above, the tunnel workstation 10 is moved backward, preferably along a traveling rail 55 laid on the bottom 54 of the tunnel 50, and then evacuated. After the tunnel workstation 10 has been evacuated, the explosives charged in the multiple blast holes drilled at the upper face 51 and the lower face 52, preferably to a drilling depth of about 1 meter, are detonated using, for example, a known detonator, to simultaneously crush the upper face 51 and the lower face 52 by blasting, thereby excavating these faces 51, 52 for each blasting span, preferably with an excavation thickness of about 1 meter, while maintaining a bench length of, for example, about 2 to 6 meters. Thereafter, for example, by passing through the above-mentioned vehicle space 20 held by the tunnel workstation 10 which has been retracted to the rear, loading machinery such as a backhoe or wheel loader, or a transport vehicle such as a dump truck can be used to move to an area close to the bench portion 56, and the excavation debris such as rock blocks generated by the blasting can be transported outside the tunnel 50.

[0057] For each blasting span, preferably about 1 meter thick, the excavated debris, such as rock blocks, generated by the blasting is removed from the tunnel 50 by heavy loading equipment or a transport vehicle. The retracted tunnel workstation 10 can then be moved forward along the traveling rails 55 and reinstalled in an area adjacent to the bench section 56. After the tunnel workstation 10 is reinstalled, for each blasting span, preferably about 1 meter wide, the divided support members 27a and 27b constituting the steel support member 27, e.g., H-shaped steel, are erected in front of the newly formed upper face 51 and lower face 52, respectively, as shown in FIGS. 11(a)-(d) and 12(a)-(d). At the same time, work can be carried out to spray concrete, for example, toward the inner peripheral wall surface 53 of the tunnel 50 in the area of ​​each blasting span, which is exposed in the excavation width of about 1 meter, up to the newly erected divided support members 27a and 27b. This makes it possible to protect the newly exposed inner wall surface 53 of the tunnel 50 in the area corresponding to each blasting span, and also makes it possible to secure the newly erected divided support members 27a, 27b to the inner wall surface 53 of the tunnel 50.

[0058] That is, in the mountain tunnel construction method using the tunnel workstation 10 of this embodiment, as shown in FIGS. 11(a) to 11(d), a transport vehicle, for example, a trailer 57, which is loaded with a plurality of divided support members 27a, 27b made of, for example, H-shaped steel, which are erected along the inner peripheral wall surface 53 of the tunnel 50 and integrally form the support member 27, is parked in the vehicle space 20 held preferably between the middle frame portion 12 and the lower frame portion 13 on both the left and right sides, and then, in a state where the trailer 57 is parked in the vehicle space 20 held preferably between the middle frame portion 12 and the lower frame portion 13 on both the left and right sides, a first gripping step (see FIGS. 11(a) and 11(b)) is performed in which the gripping attachment portions 18c of the erectors 18 on both the left and right sides, which have their base portions 18a retracted to the rear side in the axial direction X of the tunnel 50, grip, for example, a pair of upper divided support members 27a each having a curved outer peripheral portion installed in the upper portion, in a state facing forward opposite to the working face 51; The boom section 18b is extended and retracted to move the upper divided support member 27a grasped by the grasping attachment section 18c to the front of the tunnel face 51 while avoiding the upper divided support member 27a previously secured to the inner peripheral wall surface 53 of the upper section of the tunnel 50 in the inner region of the upper divided support member 27a, and the upper divided support member 27a is erected at a predetermined position in front of the tunnel face 51 so as to be aligned with the inner peripheral wall surface 53 of the excavated upper section. and a first joining process (FIG. 11(d)) in which the gauge body 17c of the man gauge 17 is advanced in the axial direction X of the tunnel 50 toward the upper face 51 and the boom section 17b is extended and retracted so that the pair of upper divided support members 27a erected in the first erection process are joined together at their upper end portions by a worker using the gauge body 17c of the man gauge 17 as a work platform.

[0059] 12(a) to 12(d), the mountain tunnel construction method using the tunnel workstation 10 of this embodiment includes a second gripping step (see FIGS. 12(a) and 12(b)) in which the gripping attachment parts 18c of the erectors 18 on both the left and right sides, whose base parts 18a have been retracted to the rear side in the axial direction X of the tunnel 50, grip, for example, a pair of linear lower divided support members 27b installed in the lower section, while facing forward opposite the face 52; and a second gripping step (see FIGS. 12(a) and 12(b)) in which the base parts 18a of the erectors 18 are advanced in the axial direction X of the tunnel 50 toward the face 52, and the boom parts 18b are made swivelingly movable downward, so that the lower divided support members 27b gripped by the gripping attachment parts 18c are gripped against the inner peripheral wall of the upper section of the tunnel 50, whose lower part has been released, for example, by excavation by blasting the lower section. 11(c)), in which the upper divided support member 27b is erected at a predetermined position in front of the lower face 52 so as to be continuous with the lower end of the upper divided support member 27a fixed to the inner peripheral wall surface 53 of the excavated lower section, and aligned with the inner peripheral wall surface 53 of the excavated lower section; and in which the deck body 15a of the liftable slide deck 15 is advanced in the axial direction X of the tunnel 50 toward the lower face 52, and is made capable of swinging downward, so that the upper end of the lower divided support member 27b erected in the second erection step is joined to the lower end of the upper divided support member 27a fixed previously to the inner peripheral wall surface 53 of the upper section of the tunnel 50, by the work of a worker using the widened deck body 15a of the liftable slide deck 15 as a work scaffold, so as to be continuous as a single unit (see FIG. 11(d)).

[0060] Here, in the above-mentioned second gripping step, the gripping attachment portion 18c of the erector 18, which has retracted the base portion 18a to the rear side in the axial direction X of the tunnel 50, can grip the lower divided support member 27b to be installed in the lower portion from, for example, a trailer 57, which is a transport vehicle that has been loaded with and transported a plurality of divided support members 27a, 27b, for example made of H-shaped steel, and which is preferably parked in the vehicle space 20 held between the middle frame portion 12 and the lower frame portion 13 on both the left and right sides.

[0061] After erecting a pair of upper divided support members 27a and a pair of lower divided support members 27b using the above-mentioned first erection process and second erection process, and joining these erected support members 27a, 27b using the above-mentioned first joining process and second joining process, the tunnel workstation 10 is preferably moved backward along the traveling rails 55 laid on the bottom portion 54 of the tunnel 50 and retracted, and then a known spraying work vehicle is passed through, for example, the above-mentioned vehicle space 20 held in the retracted tunnel workstation 10, and moved to an area close to the bench portion 56 and installed. Thereafter, as described above, for each blasting span area with an excavation width of approximately 1 m up to the newly erected divided support members 27a, 27b, spraying, for example, sprayed concrete from a spraying vehicle toward each of the inner wall surfaces 53 of the upper and lower parts of the tunnel 50 protects the inner wall surfaces 53 of the tunnel 50 in each newly exposed blasting span area and also fixes the newly erected divided support members 27a, 27b to the inner wall surface 53 of the tunnel 50.

[0062] Furthermore, after the newly erected divided support members 27a, 27b have been fixed to the inner wall surfaces 53 of the upper and lower sections of the tunnel 50, for example by spraying them with shotcrete, the tunnel workstation 10 that had been retracted can be moved forward again along the traveling rails 55 and reinstalled in an area close to the bench section 56. After that, for each inner wall surface 53 of the tunnel 50 in the area of ​​each blasting span where the new concrete has been sprayed, as shown in Figures 13(a) and (b), multiple rock bolt holes 58 can be drilled toward the ground on the outer periphery, and rock bolts 59 can be fixed into each of these rock bolt holes 58 to reinforce the inner wall surface 53 and the ground on the outer periphery.

[0063] That is, the mountain tunnel construction method using the tunnel workstation 10 of this embodiment can include, as shown in Figures 13(a) and (b), an upper rock bolt fixing process in which rock bolts 59 are fixed into each of a plurality of rock bolt holes 58 drilled into the inner wall surface 53 of the upper section of the tunnel 50 by the drilling machine body 16c of the drilling machine (upper stage drilling machine) 16 of the upper frame section 11, and a lower rock bolt fixing process in which rock bolts 59 are fixed into each of a plurality of rock bolt holes 58 drilled into the inner wall surface 53 of the lower section of the tunnel 50 by the drilling machine body 16c of the drilling machine (lower stage drilling machine) 16' of the lower frame section 13. In the upper-stage lock bolt fixing process, the lock bolts 59 are fixed in the multiple lock bolt holes 58 in the upper stage portion by operation or work by a worker using the gauge body 17c of the man gauge 17 advanced in the axial direction X of the tunnel 50 as a work foothold (see FIG. 13(a)), and by operation or work by a worker using the deck body 15a of the widened liftable slide deck 15 advanced in the axial direction X of the tunnel 50 as a work foothold (see FIGS. 3(a) and 3(b)). In the lower-stage lock bolt fixing process, the lock bolts 59 are fixed in the multiple lock bolt holes 58 in the lower stage portion by operation or work by a worker using the deck body 15a of the widened liftable slide deck 15 advanced in the axial direction X of the tunnel 50 as a work foothold (see FIG. 3(a)).

[0064] Furthermore, in the upper rock bolt installation process, the work of drilling and forming a plurality of rock bolt holes 58 in the inner peripheral wall surface 53 of the upper section of the tunnel 50 using the drilling machine body 16c of the upper stage drilling machine 16 can be performed by driving the drilling machine body 16c while the drilling machine body 16c of the upper stage drilling machine 16 is facing preferably vertically to the inner peripheral wall surface 53 of the upper section of the bench section 56 (see Figure 13(a)) and facing radially. This makes it possible to form a plurality of rock bolt holes 58 in the inner peripheral wall surface 53 of the upper section at predetermined circumferential intervals and extending radially (see Figure 13(b)). A rock bolt 59 is inserted into each of the formed rock bolt holes 58 using, for example, a known bolt insertion device and temporarily fixed therein, and a filling hardening agent is injected into the rock bolt holes 58 with the rock bolt 59 inserted to harden it.Furthermore, by fastening the base end portion of the rock bolt 59 to the inner wall surface 53 of the tunnel 50, the rock bolt 59 is firmly fixed to the ground on the inner wall surface 53, making it possible to effectively reinforce the inner wall surface 53 of the upper section and the ground around it (see Figure 13(b)).

[0065] Similarly, in the lower rock bolt installation process, the work of drilling and forming a plurality of rock bolt holes 58 in the inner wall surface 53 of the lower section of the tunnel 50 using the drilling machine body 16c of the lower stage drilling machine 16' can be performed by driving the drilling machine body 16c while facing the inner wall surface 53 of the lower section of the bench section 56, preferably perpendicularly in the lateral direction (see Figure 13(a)), and facing radially. This makes it possible to form a plurality of rock bolt holes 58 in the inner wall surface 53 of the lower section at predetermined circumferential intervals, extending radially. As in the upper rock bolt fixing process, rock bolts 59 are inserted into each of the created rock bolt holes 58 and temporarily fixed, and a filling hardening agent is injected to harden them.Furthermore, the base ends of the rock bolts 59 are fastened to the inner wall surface 53 of the tunnel 50, thereby firmly fixing the rock bolts 59 to the ground on the inner wall surface 53 and effectively reinforcing the inner wall surface 53 of the lower section and the ground around it (see Figure 13(b)).

[0066] As a result, the tunnel workstation 10 for the mini bench cut method of this embodiment, which has the above-mentioned configuration, and the mountain tunnel construction method using the tunnel workstation 10, make it possible to efficiently construct mountain tunnels using the mini bench cut method while achieving a high level of mechanization.

[0067] Furthermore, in the mountain tunnel construction method using the tunnel workstation 10 of this embodiment, the erector 18 (see FIG. 2) attached to each middle frame part 12 of the tunnel workstation 10 can be attached interchangeably with, for example, a drilling machine 16" (see FIG. 14) similar to the upper drilling machine 16, which is slidable in the axial direction of the tunnel 50 and swingable up, down, left, and right. For example, since the grade of the ground varies depending on the conditions of the ground where the mountain tunnel 50 is to be formed, it is possible to use a mini bench cut method (see FIG. 1(a)) and ground suitable for the full section method (see FIG. 14) coexist on the planned line of the tunnel 50. For example, it is possible to excavate the working faces 51, 52, 60 by excavating the tunnel face 51, 52, 60 by changing the erector 18 attached to the middle frame 12 and the boring machine 16" in accordance with changes in the ground grade via a construction vehicle (not shown) held in the above-mentioned parking space 20 (see FIG. 1(b)) held by a tunnel workstation 10 for the mini bench cut method.

[0068] Here, switching from the mini bench cut method to the full section method can be carried out by stopping excavation of the upper part of the bench section 56, preferably using blast holes drilled into the upper face 51 by a drilling machine (upper stage drilling machine) 16 attached to the upper frame section 11, and excavating only the lower part remaining from the mini bench cut method using blast holes drilled into the lower face 51 by a drilling machine (lower stage drilling machine) 16' attached to the lower frame section 13, thereby forming the face 60 (see Figure 14) to be excavated by the full section method.

[0069] On the other hand, switching from the full section method to the mini bench cut method can be preferably carried out by excavating only the upper part of the face 60, which is excavated by the full section method, using blast holes drilled in the upper part of the face 60 by a drilling machine (upper stage drilling machine) 16 attached to the upper frame section 11, to form the upper face 51 and lower face 52, which are excavated by the mini bench cut method.

[0070] Furthermore, as mentioned above, since the grade of the ground varies depending on the conditions of the ground where the mountain tunnel 50 is to be formed, if ground suitable for excavation using the mini bench cut method (see Figure 1(a)) and ground suitable for excavation using the full section method (see Figure 14) are mixed on the planned line of the tunnel 50, in ground where excavation using the mini bench cut method is applied, the above-mentioned lower rock bolt fixing process is carried out to fix rock bolts 59 in each of the multiple rock bolt holes 58 in the lower section, and in ground where excavation using the full section method is applied, the full section lower rock bolt fixing process is carried out to fix rock bolts 59 in each of the multiple rock bolt holes 58 in the lower section. In the full cross-section lower rock bolt fixing process, as shown in Figure 15, the deck body 15a of the widened liftable slide deck 15 is swiveled downward from a position similar to the forward position in the upper rock bolt fixing process in the mini bench cut method described above, and is operated or worked on by a worker using the deck body 15a as a work platform (see Figure 15), to fix the lock bolts 59 in each of the multiple lock bolt holes 58 in the lower section.

[0071] Furthermore, in the full cross-section lower lock bolt fixing process, when the deck body 15a of the liftable slide deck is swiveled downward from the forward position in the above-mentioned upper lock bolt fixing process, it is conceivable that the rotational movement will cause the deck body 15a to move too far away from the lower portion of the working face 60; however, preferably, the deck body 15a of the widened liftable slide deck is moved further forward by sliding the slide base portion 15b, thereby making it possible to easily perform the operation or task of fixing each of the lock bolts 59 in the multiple lock bolt holes 58 in the lower portion.

[0072] As a result, according to the mountain tunnel construction method using the tunnel workstation 10 of this embodiment, it is possible to efficiently carry out the construction of mountain tunnels using the mini bench cut method while achieving a high level of mechanization, and it is also possible to effectively avoid the impact on the work of loading explosives due to the skin of the ground on the inner wall surface of the tunnel.

[0073] The present invention is not limited to the above-described embodiment and various modifications are possible. For example, the tunnel workstation for the mini bench cut method does not necessarily need to have an interference prevention notch formed under the tip of the middle frame that protrudes further toward the tunnel face in the axial direction than the lower frame, and does not necessarily need to have a liftable slide deck attached to the underside of the upper frame that serves as a foothold for workers. [Explanation of symbols]

[0074] 10. Tunnel workstation for mini bench cut construction method 11 Upper frame section 11a Top part 11b Central guide rail 11c Side guide rail 12 Middle frame section 12a Top part 12b Erector guide rail 12c Interference prevention notch 13 Lower frame section 13a Top part 14a Main support member 14a' Lower main support member 14b Sub-support member 15 Liftable slide deck 15a Deck body 15b Slide base 15c Rotating arm 15d Lower scaffolding board 15e Upper scaffolding board 15f Handrail to prevent falling 16 Upper stage drilling machine 16a Base part 16b Boom section 16c drilling machine body 16d cab 16' Lower Drilling Machine 16" drilling machine 17 Mangauge 17a Base part 17b Boom section 17c gauge body 18 Erector 18a Base part 18b Boom section 18c Gripping attachment 18d Locking jig 19a Main running equipment 19b Secondary running equipment 20 Vehicle space 21 Stopper and outrigger part 22 Working deck section 23 Deck guide rail 23a Rail member 27 Supporting members 27a Upper division support member 27b Lower division support member 28 Fixing screw 30 Protective Net 50 Mountain Tunnel 51 Upper face 52 Lower face 53 Inner wall surface 53a Top part 54 Bottom part 55 Running rail 56 Bench part 57 Trailer (transport vehicle) 58 Rock bolt hole 59 Rock Bolt 60 Face excavated using full-face method X Axial direction of the tunnel Y Tunnel width direction

Claims

1. A mountain tunnel construction method using a tunnel workstation used in a mini-bench cut method, in which the bench length is shortened to 2 to 6 m, and excavation is performed while simultaneously crushing the upper and lower face faces by blasting, The tunnel workstation is composed of an upper frame section, a pair of left and right middle frame sections and a pair of left and right lower frame sections provided in the lower part of the upper frame section via support members that support the upper frame section from below, and has an overall gate-shaped front shape that maintains a vehicle space that allows construction vehicles to pass between the middle frame sections and the lower frame sections on both the left and right sides in the lower area of ​​the upper frame section, A drilling machine capable of drilling holes in the upper tunnel face and inner peripheral wall surface is attached to the upper surface of the upper frame section so as to be movable in the axial direction of the tunnel and so as to be able to swivel up, down, left, and right, and a mangage, which serves as a foothold for workers, is attached to the upper frame section so as to be movable in the axial direction of the tunnel and so as to be able to swivel up, down, left, and right, A liftable slide deck that can be expanded in the width direction of the tunnel and serves as a foothold for workers is attached to the underside of the upper frame section so as to be slidable in the axial direction of the tunnel and swingable up and down. Each of the middle frame sections is provided with an erector that grips the support members that are erected along the inner wall surface of the tunnel after excavation, and is attached so as to be movable in the axial direction of the tunnel and so as to be swingable up, down, left, and right. a drilling machine capable of drilling holes in the face and inner wall surface of the lower section of the tunnel is attached to each of the lower frame sections so as to be swingable up, down, left and right, and a traveling device is provided for traveling the tunnel workstation in the axial direction of the tunnel; A mountain tunnel construction method using a tunnel workstation that includes a protective net installation process in which, when workers use the gauge body of the man gauge or the deck body of the liftable slide deck as a work foothold to load explosives into each of the blast holes drilled in the upper and lower face faces by the drilling machine body of the boring machine, the protective net stretched between the left and right gripping attachment parts is installed above the gauge body of the man gauge or the deck body of the liftable slide deck by engaging both end parts with engaging devices provided on the gripping attachment parts of the left and right erectors via engaging parts.

2. 2. A mountain tunnel construction method using a tunnel workstation according to claim 1, further comprising: a first protective net installation step of installing a protective net stretched between the engaging devices provided on the gripping attachment parts of the left and right erectors above the gauge body of the man gauge; and in the first protective net installation step, while the gauge body is retracted rearward, the gripping attachment parts of the pair of erectors are moved so that they protrude forward from the upper frame part and are also moved upward, so that the protective net stretched between the engaging devices on both sides is positioned close to the upper face of the tunnel and covers the top end portion of the inner wall of the bench part of the tunnel from below, and then the gauge body of the man gauge is moved forward and positioned in the area below the protective net that has been installed to cover the top end portion of the inner wall of the bench part of the tunnel.

3. 2. A mountain tunnel construction method using a tunnel workstation as set forth in claim 1, which includes a second protective net placement process, in which the protective net stretched between the engaging devices provided on the gripping attachment parts of the left and right erectors is placed above the liftable slide deck when workers use the deck body of the liftable slide deck as a work foothold to load explosives into each of the blast holes drilled in the upper face by the boring machine body of the boring machine.

4. 4. A mountain tunnel construction method using a tunnel workstation as described in claim 3, wherein, in the second protective net installation process, while the deck main body is moved rearward without being widened, the gripping attachment parts of the pair of erectors are moved so that they protrude forward from the upper frame part and are moved upward, so that the protective net stretched between the engaging devices on both sides is placed close to the upper face and covers the upper part of the inner wall surface of the bench part of the tunnel from below, and then the deck main body is moved forward and positioned in the area below the protective net that has been placed covering the upper part of the inner wall surface of the bench part of the tunnel, and the deck main body is widened.

5. 2. A mountain tunnel construction method using a tunnel workstation according to claim 1, further comprising a third protective net installation step, in which when workers use the expanded deck body of the liftable slide deck or the bottom of the tunnel as a work foothold to load explosives into each of the blast holes drilled in the lower face by the boring machine body of the boring machine, the protective net is suspended between the left and right holding attachment parts and tensioned at the middle of the height of the bench part of the tunnel by engaging both ends 30a of the net with the hanging engaging devices provided on the holding attachment parts of the left and right erectors via the locking parts.

6. 2. A mountain tunnel construction method using a tunnel workstation as claimed in claim 1, further comprising a fourth protective net installation step of installing the protective net stretched between the engaging devices provided on the gripping attachment parts of the left and right erectors above the expanded deck body of the liftable slide deck or the bottom part of the tunnel when workers use the expanded deck body of the liftable slide deck or the bottom part of the tunnel as a work foothold to load explosives into each blast hole drilled in the lower face by the boring machine body of the boring machine.

7. 7. A mountain tunnel construction method using a tunnel workstation according to claim 6, wherein, in the fourth protective net installation step, preferably with the deck body retracted rearward without being widened, the gripping attachment parts of the pair of erectors are extended forward from the upper frame part and moved to a position in front of the lower face and to a position higher than the height of the tunnel bench, so that the protective net stretched between the locking devices on both sides is close to a position in front of the lower face and is installed in a state covering from below an upper half of the inner wall surface in front of the tunnel bench, and then the deck body of the liftable slide deck is moved forward and positioned below the protective net that has been installed covering the upper half of the inner wall surface in front of the tunnel bench, and the deck body is widened to allow blasting work to be performed from the widened work platform or using the bottom of the tunnel in front of the lower face as a work platform for blasting work.

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