KR20250115166A - Construction method of narrow-pillar tunnel using reinforcing system - Google Patents

Abstract

The present invention relates to a method for constructing a close-contact tunnel, which can exert a composite bearing capacity immediately after tunnel excavation by utilizing the original ground strength of the pillar portion and the maximum member force of the tunnel support member by installing a support member so that the end of a tie bolt inserted toward the pillar portion penetrates between the support members installed along the length of the tunnel to support the inner surface of the tunnel.
The present invention comprises the steps of: (a) excavating a preceding tunnel; (b) mutually spaced-apart installing a plurality of rows of first steel supports to support the inner surface of the preceding tunnel; (c) penetrating and constructing tie bolts on one side of the excavated preceding tunnel where a pillar portion is to be formed; (d) installing a steel support bearing member on the end of the tie bolt on the preceding tunnel side so that both ends are supported by the first steel supports on both adjacent sides; (e) pouring shotcrete on the inner surface of the preceding tunnel; (f) excavating a subsequent tunnel so that the pillar portion is formed between the subsequent tunnel and the preceding tunnel so that the end of the tie bolt on the subsequent tunnel side is exposed; (g) mutually spaced-apart installing a plurality of rows of second steel supports to support the inner surface of the subsequent tunnel; (h) installing a steel support bearing member on the end of the tie bolt on the subsequent tunnel side so that both ends are supported by the second steel supports on both adjacent sides; and (i) a step of pouring shotcrete on the inner surface of the rear tunnel;

Description

Construction method of narrow-pillar tunnel using reinforcing system

The present invention relates to a method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a support beam, which can exert a composite bearing capacity immediately after tunnel excavation by utilizing the original ground strength of the tunnel pillar portion and the maximum member force of the tunnel support member by installing a support beam bearing member so that the end of a tie bolt inserted toward the pillar portion penetrates between the support beams installed along the length of the tunnel to support the inner surface of the tunnel.

Tunnel designs are classified into single-track parallel tunnels, large-section tunnels, two-arch tunnels, and close-track parallel tunnels depending on the tunnel cross-section.

Road tunnels are typically constructed as simple, single-track parallel tunnels. These typical parallel tunnels require sufficient separation between the two tunnels to ensure structural stability. This separation is typically designed to be at least 1.5 times the tunnel width (D). In this case, the road connecting the tunnel must also be separated by the same distance, necessitating a larger road surface area.

However, it is not easy to purchase land in urban areas, and as social demands for environmental conservation are strengthened, it is difficult to secure a distance of more than 1.5D between tunnels.

In cases where paper acceptance is difficult or an existing security building exists close to a new tunnel, making it difficult to plan a general parallel tunnel, a large-section single-track tunnel or a 2-Arch tunnel format can be applied.

However, large-diameter single-track tunnels require excessive excavation due to their high tunnel height. Furthermore, the excavation must be performed in two sections, resulting in significant construction costs and time constraints. In particular, large-diameter single-track tunnels are difficult to apply to urban tunnels, where rock quality is poor and land acquisition is extremely limited.

Therefore, in cases where securing a sufficient distance between tunnels is difficult, a two-arch tunnel can be applied to reduce the gap between parallel tunnels. A two-arch tunnel involves first constructing a central tunnel in the central area where two tunnels will be formed, forming a central wall. Then, the main tunnels are sequentially excavated on either side of the wall. However, this method complicates the construction process, requiring significant time and cost due to the central tunnel being excavated, the central wall being constructed, and then the main tunnels being expanded sequentially. Furthermore, groundwater accumulation above the central tunnel increases maintenance costs during operation.

Recently, due to the significant difficulty in acquiring land in urban areas and concerns about environmental damage, plans for tunnels with significantly closer spacing between adjacent tunnels are increasing. Therefore, the close-contact tunneling method may be considered.

The close-contact tunnel was developed to complement the shortcomings of existing general contact tunnels and 2-Arch tunnels. It is a construction method that can secure the constructability, structural stability, and economic feasibility of a tunnel by installing reinforcement materials in the pillar section and increasing the shear strength of the ground through pressurized grouting and pretensioning to minimize displacement.

During the excavation of a typical parallel tunnel, three areas occur: the tunnel excavation destruction area (①), the tunnel outer damage area (②), and the tunnel pillar disturbance area (③) (Fig. 1). However, in a close parallel tunnel, the tunnel pillar width is narrow, so the damage areas (②) of the preceding tunnel (1a) and the succeeding tunnel (1b) overlap, resulting in lower structural stability compared to a typical parallel tunnel.

The damaged area (②) on the outside of the tunnel is formed by the direct vibration energy of tunnel blasting on the tunnel excavation surface, thereby forming a permanent ground relaxation area with a thickness of d=0.5∼1.0m. The tunnel pillar (10) disturbance area (③) is formed by the expansion of the tunnel pillar ground relaxation area due to the deformation of the preceding tunnel (1a) and the succeeding tunnel (1b), and the ground disturbance area and condition are generated differently depending on the deformation and strength characteristics of the tunnel pillar ground, the tunnel excavation method, or the application of the support system. In particular, the tunnel pillar disturbance area is characterized by progressing more rapidly after the excavation of the succeeding tunnel (1b) than that of the preceding tunnel (1a) (see ground stress during excavation of a closely parallel tunnel in Fig. 2).

Since the width of the pillars in a close-contact tunnel is narrow, the area of pillar damage and disturbance caused by tunnel excavation is a major factor influencing the stability of the tunnel.

In the conventional close-contact tunnel construction method illustrated in Fig. 3, damage to the tunnel pillar (10) is minimized by excavation using vibration-controlled blasting, and the stability of the tunnel pillar (10) is secured by a high-strength reinforcement system such as tie bolts (3) and reinforcing bar (50) reinforced shotcrete (5). However, the construction process is complicated due to longitudinal tunnel segmentation excavation (post-pillar excavation) and tie bolts (3) and reinforcing bar shotcrete (5) pouring of the pillar (10), and there is a problem that the constructability is lower than that of a general parallel tunnel (Patent Registration No. 10-1028535).

In particular, the tie bolt (3) and reinforced shotcrete (5) reinforcement of the tunnel pillar (10) are constructed integrally for the 1.0 to 3.0D area behind the tunnel face to ensure construction quality. Therefore, if the ground conditions of the tunnel pillar are poor, it is difficult to expect the bearing capacity of the pillar immediately after excavation, and there is a concern that the tunnel stability may be reduced, such as additional ground subsidence occurring due to the expansion of the pillar disturbance area. Therefore, for the pillar unsupported section of the subsequent tunnel (1b), excavation is performed while leaving some width, and then reinforced steel and shotcrete construction are performed at the rear to secure the bearing capacity, and then the remaining width is excavated and removed. Therefore, the construction is cumbersome due to the back-and-forth excavation, and it takes a lot of time.

Meanwhile, the existing tunnel pillar reinforcement method that mainly reinforces the tunnel pillar (10) reinforces the pillar (10) by installing tie bolts (3) such as steel wires or steel bars on the pillar (10) and applying tension and grouting (Fig. 4, Patent No. 10-1353882).

Since this conventional technology cannot introduce tension force to the tie bolt (3) between the face of the subsequent tunnel (1b) and the face of the preceding tunnel (1a), an unsupported section of the pillar occurs within the preceding tunnel (1a). In addition, the tie bolt reinforcement structure is complex, making construction difficult, and since the actual tunnel pillar reinforcement is performed in the 1.0 to 3.0D section behind the tunnel face, it is difficult to expect the pillar to immediately exert its bearing capacity, and the expansion of the pillar ground disturbance area is inevitable. Furthermore, if excessive ground load is continuously applied to the support portions of the tie bolts (3) at both ends during tunnel excavation, there is a concern that the bearing capacity may be reduced due to damage to the ends of the tie bolts (3) or the bearing plates.

In order to solve the above problems, the present invention provides a method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a support beam that can exert a composite bearing capacity immediately after tunnel excavation by utilizing the original ground strength of the tunnel pillar and the maximum member strength of the tunnel support material.

The present invention, according to a preferred embodiment, relates to a method for constructing a close-contact tunnel in which a preceding tunnel and a succeeding tunnel are constructed in parallel, comprising the steps of: (a) excavating a preceding tunnel; (b) installing a plurality of rows of first steel supports, which support the inner surface of the preceding tunnel, with a distance therebetween; (c) constructing tie bolts on one side of the excavated preceding tunnel where a pillar portion is to be formed; (d) installing a steel support bearing member on the end of the tie bolt on the preceding tunnel side so that both ends are supported by the first steel supports on both adjacent sides; (e) pouring shotcrete on the inner surface of the preceding tunnel; (f) excavating a succeeding tunnel so that the pillar portion is formed between the preceding tunnel and the succeeding tunnel by exposing the ends of the tie bolts on the succeeding tunnel side; (g) installing a plurality of rows of second steel supports, which support the inner surface of the succeeding tunnel, with a distance therebetween; (h) a step of installing a steel support bearing member on the end of the tie bolt on the subsequent tunnel side so that both ends are supported by the second steel support beams on both adjacent sides; and (i) a step of pouring shotcrete on the inner surface of the subsequent tunnel; a method for constructing a close-contact tunnel using a steel support tie bolt reinforcement system is provided.

According to another preferred embodiment, the present invention provides a method for constructing a close-contact tunnel using a steel beam fastening tie bolt reinforcement system, characterized in that the first and second steel beams are H-shaped steel beams, and the steel beam pressure member is supported on the inner surface of the outer flange of the first and second steel beams.

According to another preferred embodiment, the present invention provides a method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a steel beam, characterized in that the steel beam support member is composed of a pair of flanges and a web connecting one end of the pair of flanges, and the web is supported on the inner surface of the outer flanges of the first and second steel beams.

According to another preferred embodiment, the present invention provides a method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a steel beam, characterized in that the first and second steel beams further include a support member formed in a vertical direction with a back surface that is in close contact with the inner surface of the outer flange of the first and second steel beams and a front surface that supports the steel beam support member.

According to another preferred embodiment, the present invention provides a method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a steel beam, characterized in that the support member comprises a fixed plate that is in close contact with the inner surface of the outer flange of the first and second steel beams, a movable plate that is rotatably connected to the upper or lower end of the fixed plate to support the steel beam support member, and an angle adjusting member that is provided between the fixed plate and the movable plate to fix the angle of the movable plate.

According to another preferred embodiment, the present invention provides a method for constructing a close-contact tunnel using a reinforcing tie bolt system for fastening a reinforcing bar, characterized in that a mounting portion on which an end of the reinforcing bar pressure member is mounted is protruded from the lower front surface of the movable plate.

According to the present invention, a method for constructing a close-contact tunnel can be provided in which a tie bolt and a steel support beam exert a composite support force to reinforce a pillar section by installing a steel support beam bearing member so that the end of a tie bolt inserted toward a pillar section penetrates between steel support beams installed along the length of the tunnel to support the inner surface of the tunnel.

Accordingly, first, by reinforcing the tunnel pillar early in a state where the supporting force due to the arching effect of the tunnel face is exerted, the pillar deformation can be minimized, and the pillar disturbance area can be minimized by exerting the maximum supporting force.

Second, by utilizing the original ground strength of the tunnel pillar and the maximum member strength of the tunnel support material, the composite bearing capacity can be exerted immediately after tunnel excavation.

Third, a close parallel tunnel can be constructed through a simple and repetitive process by applying the same construction process as a general parallel tunnel.

Figure 1 is a drawing showing the concept of ground relaxation of a pillar in a close-contact tunnel.
Figure 2 is a drawing showing ground stress during excavation of a close-contact tunnel.
Figure 3 is a drawing showing a conventional pillar reinforcement method using reinforced shotcrete.
Figure 4 is a drawing showing a conventional pillar reinforcement method using tie bolt tension.
Figure 5 is a cross-sectional view showing a close-contact tunnel constructed according to the present invention.
Figures 6 to 14 are cross-sectional views each showing a step-by-step process of the method for constructing a close-contact tunnel of the present invention.
Figure 15 is a perspective view showing the connection relationship between a support beam and a tie bolt by a support beam pressure member.
Figure 16 is a cross-sectional view showing the effect of the blind arching.
Figure 17 is a perspective view showing the connection relationship between the support member and the support member.
Figure 18 is a perspective view showing the installation state of the steel support pressure member.
Fig. 19 is a perspective view showing a supporting member.
Figure 20 is a cross-sectional view showing a state in which a support member is installed by a support member.
Figure 21 is a perspective view showing a state in which a support member is installed by a support member.

Hereinafter, the present invention will be described in detail with reference to the attached drawings and preferred embodiments.

Fig. 5 is a cross-sectional view illustrating a close-contact tunnel constructed according to the present invention, and Figs. 6 to 14 are plan sectional views illustrating step-by-step processes of the close-contact tunnel construction method of the present invention, respectively. Fig. 15 is a perspective view illustrating the connection relationship between a support beam and a tie bolt by a support pressure member, and Fig. 16 is a plan sectional view illustrating the face arching effect.

As illustrated in FIGS. 5, 6 to 14, etc., a method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a steel beam of the present invention relates to a method for constructing a close-contact tunnel in which a preceding tunnel (1a) and a succeeding tunnel (1b) are constructed in parallel, comprising the steps of: (a) excavating a preceding tunnel (1a); (b) installing a plurality of rows of first steel beams (2a) spaced apart from each other to support the inner surface of the preceding tunnel (1a); (c) constructing a tie bolt (3) by penetrating into one side of the excavated preceding tunnel (1a) where a pillar portion (10) is to be formed; (d) installing a steel beam bearing member (4) on the end of the tie bolt (3) on the preceding tunnel (1a) side so that both ends are supported by the first steel beams (2a) on both adjacent sides; (e) pouring shotcrete (5) onto the inner surface of the preceding tunnel (1a); (f) forming the pillar portion (10) between the preceding tunnel (1a) and the preceding tunnel (1b) by excavating the succeeding tunnel (1b) so that the succeeding tunnel (1b) side end of the tie bolt (3) is exposed; (g) installing a plurality of rows of second steel supports (2b) to support the inner surface of the succeeding tunnel (1b) at a distance from each other; (h) installing a steel support pressure member (4) at the succeeding tunnel (1b) side end of the tie bolt (3) so that both ends are supported by the adjacent second steel supports (2b) on both sides; and (i) pouring shotcrete (5) onto the inner surface of the succeeding tunnel (1b).

The present invention provides a method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a support beam that can exert a composite support force immediately after tunnel excavation by utilizing the original ground strength of a tunnel pillar (10) and the maximum member strength of a tunnel support material.

The present invention is for constructing a close parallel tunnel in which a preceding tunnel (1a) and a succeeding tunnel (1b) are constructed in parallel and a pillar (10) is formed between the preceding tunnel (1a) and the succeeding tunnel (1b).

The present invention may be applied to the entire tunnel section, or may be applied to only a portion of the tunnel section depending on ground conditions.

In the present invention, first, (a) the ground is excavated to a certain depth to form a preliminary tunnel (1a) (Fig. 6).

At this time, in order to minimize ground relaxation in the area of damage to the pilaster due to tunnel excavation and maintain the original ground strength characteristics, a linear vacuum hole is installed outside the excavation line of the pilaster (10) of the preceding tunnel (1a) so that the ground can be excavated by vibration-controlled blasting.

If the tunnel cross-section is large, it can be divided into upper and lower halves and excavated separately.

Next, (b) multiple rows of first reinforcement beams (2a) supporting the inner surface of the preceding tunnel (1a) are installed spaced apart from each other (Fig. 7).

Immediately following the excavation of the above-mentioned preceding tunnel (1a), the first reinforcement beam (2a) is installed.

The above first support beam (2a) minimizes the relaxation of the ground around the tunnel immediately after excavation and suppresses excessive initial displacement of the excavation surface.

The above first support member (2a) is installed in the direction of the tunnel width, and is formed in a shape corresponding to the tunnel shape to support the inner surface of the preceding tunnel (1a).

The first support beam (2a) is installed sequentially in multiple pieces so as to be spaced apart in the direction of the tunnel length.

After installing the first reinforcement member (2a) above, (c) a tie bolt (3) is driven into one side of the excavated preceding tunnel (1a) where the pillar portion (10) will be formed (Fig. 8).

The above tie bolt (3) can be constructed between adjacent first reinforcement beams (2a).

And (d) a support member (4) is installed on the end of the preceding tunnel (1a) side of the tie bolt (3) so that both ends are supported by the first support members (2a) on both sides (Fig. 9).

After constructing the first support beam (2a) and tie bolt (3), a support beam pressure member (4) is installed on the end of the preceding tunnel (1a) side of the tie bolt (3).

The above tie bolt (3) has an end that penetrates the steel support pressure member (4) and protrudes toward the front of the steel support pressure member (4). A nut (31) can be fastened to the protruding end of the tie bolt (3). If necessary, a pressure plate (32) can be installed before fastening the nut (31) (Fig. 17).

The above-mentioned steel support pressure member (4) is connected to the tie bolt (3) in the center, and both ends are supported by the first steel support members (2a) on both sides.

Accordingly, the load acting on the tie bolt (3) is transmitted to the first steel support beam (2a) through the steel support pressure member (4), so that the tie bolt (3) and the first steel support beam (2a) can exert a combined support force.

After the first support beam (2a), tie bolt (3), and support beam pressure member (4) are constructed, (e) shotcrete (5) is poured on the inner surface of the preceding tunnel (1a) (Fig. 10).

The above shotcrete (5) is integrated with the first reinforcement (2a) after hardening to improve the support capacity.

In order to reinforce the pillar (10) side of the preceding tunnel (1a) to a sufficient length before construction of the subsequent tunnel (1b), steps (a) to (e) are repeated once or twice or more.

Afterwards, (f) the follow-up tunnel (1b) is excavated to form the pillar portion (10) between the follow-up tunnel (1b) and the preceding tunnel (1a) so that the follow-up tunnel (1b) side end of the tie bolt (3) is exposed (Fig. 11).

The above-mentioned subsequent tunnel (1b) is constructed at a certain interval from the preceding tunnel (1a) and can be excavated in the same manner as the preceding tunnel (1a).

As the preceding tunnel (1b) is excavated, a pillar (10) having a predetermined width is formed between the preceding tunnel (1a) and the succeeding tunnel (1b).

At this time, the other end of the tie bolt (3) that was constructed to penetrate the subsequent tunnel (1b) during the construction of the preceding tunnel (1a) is exposed.

And (g) multiple rows of second reinforcement beams (2b) supporting the inner surface of the above-mentioned rear tunnel (1b) are installed spaced apart from each other (Fig. 12).

As with the preceding tunnel (1a), the subsequent tunnel (1b) is also excavated and the second support beam (2b) is installed immediately thereafter.

The above second reinforcement (2b) is formed in a shape corresponding to the tunnel shape and can support the inner surface of the subsequent tunnel (1b).

The other end of the tie bolt (3) protrudes between the adjacent second support beams (2b).

And (h) a support member (4) is installed on the end of the tie bolt (3) on the side of the subsequent tunnel (1b) so that both ends are supported by the second support members (2b) on both sides (Fig. 13, Fig. 15), and (i) shotcrete (5) is poured on the inner surface of the subsequent tunnel (1b) (Fig. 14).

After the installation of the second support beam (2b) above, a support beam pressure member (4) is installed on the tie bolt (3) protruding between the adjacent second support beams (2b).

The above-mentioned steel support member (4) is supported on both ends by the second steel support member (2b), and a nut (31) is fastened to the end of the tie bolt (3) that penetrates the steel support member (4).

Immediately after the installation of the above-mentioned steel support pressure member (4), the tie bolt (3) and the second steel support (2b) exert a combined support force to reinforce the pillar (10).

Therefore, when excavating the subsequent tunnel (1b), no unsupported section is created in the pillar (10).

The above second support beam (2b) can be installed simultaneously with the excavation of the subsequent tunnel (1b) and can be installed very close to the face (100). Therefore, the support strength due to the longitudinal arching effect of the tunnel face (100) itself and the support strength due to the second support beam (2b) and tie bolts (3) can work in combination to exert maximum support strength (Fig. 16). In addition, the stress in the pillar disturbance area can be moved to the original ground level, thereby minimizing the pillar disturbance area and minimizing deformation of the pillar (10).

In the present invention, the tie bolt (3) is connected to the support beam by the support pressure member (4), enabling immediate application of support force. Therefore, there is no need for separate drilling equipment and the construction of rock bolts, which consume a lot of air. However, rock bolts (11) can be installed in areas other than the pillar (10) (Fig. 5). In addition, since excavation can be performed in one go without leaving a pile on the side of the pillar (10), the construction period can be shortened.

Even in this case where the preceding tunnel (1a) and the succeeding tunnel (1b) are close together to form a narrow pillar (10), the pillar (10) can be reinforced immediately at the same time as the excavation of the succeeding tunnel (1b). Therefore, the preceding tunnel (1a) and succeeding tunnel (1b) can be constructed through a simple and repetitive process in the same order as a typical parallel tunnel with sufficient separation between them, and the construction period can be significantly shortened compared to the existing close parallel tunnel.

Figure 17 is a perspective view showing the connection relationship between the support member and the support member, and Figure 18 is a perspective view showing the installation state of the support member.

As shown in FIGS. 17 and 18, the first and second support beams (2a, 2b) are H-shaped steel, and the support beam pressure member (4) can be supported on the inner surface of the outer flange (21) of the first and second support beams (2a, 2b).

The above first and second support members (2a, 2b) may be H-shaped steel members composed of a pair of flanges (21, 22) and a web (23) connecting the centers of the flanges (21, 22).

The outer flange (21) of the first and second reinforcements (2a, 2b) can be in close contact with the inner surface of the tunnel.

For this purpose, the first and second H-shaped steel beams (2a, 2b) can be formed to be curved according to the shape of the tunnel.

After the first and second support beams (2a, 2b) and the support pressure member (4) are constructed, shotcrete (5) is poured onto the inner surface of the preceding and succeeding tunnels (1a, 1b), so that the first and second support beams (2a, 2b) and the support pressure member (4) are embedded within the shotcrete (5).

At this time, in order to minimize the thickness of the shotcrete (5) and reduce the amount of shotcrete (5), the steel support bearing member (4) can be inserted into the inside of the first and second steel supports (2a, 2b), that is, between the outer flange (21) and the inner flange (22), so as to be supported on the inner surface of the outer flange (21).

Here, the outer side refers to the side of the pillar (10), and the inner side refers to the inside of the tunnel.

The above-mentioned steel support member (4) is composed of a pair of flanges (41) and a web (42) connecting one end of the pair of flanges (41), so that the web (42) can be supported on the inner surface of the outer flange (21) of the first and second steel support members (2a, 2b).

The above-mentioned steel support member (4) can be configured as a T-shaped steel so that it can easily support the first and second steel support members (2a, 2b) which are H-shaped steel while exhibiting appropriate rigidity, and so that the tie bolt (3) can be easily fastened.

That is, the above-mentioned steel support member (4) may be composed of upper and lower flanges (41) and a web (42) connecting one end of the pair of flanges (41). The web (42) is supported on the inner surface of the outer flange (21) of the first and second steel support members (2a, 2b), and the flange (41) protrudes to the front of the web (42) to exert bending rigidity.

The load applied to the above tie bolt (3) is transmitted to the neighboring first and second steel supports (2a, 2b) by the bending and shear rigidity of the steel support pressure member (4).

The above tie bolt (3) penetrates the web (42) of the steel support pressure member (4), and a nut (31) can be screwed to the end of the tie bolt (3) on the inside of the web (42).

Fig. 19 is a perspective view showing a supporting member, Fig. 20 is a cross-sectional view showing a state in which a support member is installed by a supporting member, and Fig. 21 is a perspective view showing a state in which a support member is installed by a supporting member.

As shown in FIGS. 19 to 21, the first and second support members (2a, 2b) may further be provided with a support member (6) whose back surface is in close contact with the inner surface of the outer flange (21) of the first and second support members (2a, 2b) and whose front surface is formed in a vertical direction to support the support member pressure member (4).

The tunnel excavation cross-section is usually formed in a semicircular, round, or oval shape.

Accordingly, the tie bolt (3) is installed horizontally by penetrating the pillar (10) from left to right, while the first and second support beams (2a, 2b) are formed to be appropriately curved along the excavated cross-section shape of the tunnel. Therefore, depending on the position where the tie bolt (3) is installed, the direction of the tie bolt (3) and the tangent direction of the first and second support beams (2a, 2b) at the position where the tie bolt (3) is joined may not be perpendicular, and thus they may be joined at an angle to each other.

At this time, at the position where the support member (4) is connected to the tie bolt (3), the nut (31) or the support plate (32) may not be in close contact with the inner surface of the web (42) of the support member (4), making it difficult to properly transmit the load.

Accordingly, regardless of the inclination angle of the first and second support beams (2a, 2b), a support member (6) may be provided on the inner side of the outer flange (21) of the first and second support beams (2a, 2b) so that the support pressure member (4) can be arranged in a direction perpendicular to the tie bolt (3).

The front surface of the above-mentioned support member (6) is formed in a vertical direction so that the web (42) of the support member (4) is supported in close contact with it, and the back surface is formed as an inclined surface corresponding to the inclination of the first and second support members (2a, 2b) at the position where the tie bolt (3) is coupled, so that it is in close contact with the inner surface of the outer flange (21) of the first and second support members (2a, 2b).

The above support member (6) can be fixed to the first and second support members (2a, 2b) by welding or bolting.

The above-mentioned support member (6) may be composed of a fixed plate (61) that is in close contact with the inner surface of the outer flange (21) of the first and second reinforcement members (2a, 2b), a movable plate (62) that is rotatably connected to the upper or lower end of the fixed plate (61) and supports the reinforcement support pressure member (4), and an angle adjusting member (63) that is provided between the fixed plate (61) and the movable plate (62) and fixes the angle of the movable plate (62).

The above first and second supporting members (2a, 2b) are formed to be curved to correspond to the shape of the tunnel, so that their inclinations change according to the height. In this case, it may be cumbersome to use a support member (6) with a different inclination depending on the inclination of the first and second supporting members (2a, 2b).

Accordingly, the support member (6) can be configured to be variable so that the angle of the support member (6) can be adjusted according to the inclination of the first and second reinforcements (2a, 2b).

To this end, the support member (6) may be configured to rotatably connect a fixed plate (61) and a movable plate (62), and an angle adjustment member (63) may be provided between the fixed plate (61) and the movable plate (62) to adjust the angle and fix them.

The above fixed plate (61) is in close contact with the inner surface of the outer flange (21) of the first and second reinforcements (2a, 2b), and can be fixed to the outer flange (21) by welding or bolting.

The above movable plate (62) is rotatably connected to either the upper or lower end of the fixed plate (61), and a strong support pressure member (4) is installed in close contact on the front.

The above fixed plate (61) is fixed to the inner side of the outer flange (21) of the first and second reinforcements (2a, 2b), and the movable plate (62) is in a vertical direction, and the angle adjustment member (63) can fix the angle of the fixed plate (61) and the movable plate (62).

For this purpose, the angle adjustment member (63) can be configured to be adjustable in length.

For example, the angle adjustment member (63) may be composed of a first support bar (631) having one end hinged to a fixed plate (61), a second support bar (632) having one end hinged to a movable plate (62), and a coupler (633) connecting the first support bar (631) and the second support bar (632).

The angle of the movable plate (62) can be adjusted by rotating the above coupler (633).

As shown in Fig. 19, the movable plate (62) can be rotatably connected to the upper end of the fixed plate (61).

A mounting portion (621) on which the end of the above-mentioned strong support pressure member (4) is mounted can be protruded and formed on the lower front side of the above-mentioned movable plate (62).

The above first and second reinforcing members (2a, 2b) and the reinforcing member bearing member (4) are embedded in the shotcrete (5) and become one. Therefore, the reinforcing member bearing member (4) may be temporarily fixed to the first and second reinforcing members (2a, 2b) until the shotcrete (5) hardens.

However, if the above-mentioned steel support pressure member (4) is simply pressed against the front surface of the movable plate (62) of the support member (6), it is difficult to temporarily fix the position of the steel support pressure member (4) until the nut (31) is fastened to the tie bolt (3) to pressurize the steel support pressure member (4) toward the support member (6). In addition, in order to fasten the nut (31), a total of two workers are required, one to fix the steel support pressure member (4) and one to fasten the nut (31).

Therefore, when installing the above-mentioned steel support pressure member (4), a mounting portion (621) can be formed protrudingly on the lower front surface of the movable plate (62) so that the position of the steel support pressure member (4) can be temporarily fixed.

Since the above movable plate (62) is provided in a vertical direction, the above-mentioned mounting portion (621) can be formed by bending in a horizontal direction at the lower end of the movable plate (62).

Accordingly, the nut (31) can be fastened to the tie bolt (3) while the steel support pressure member (4) is placed on the upper surface of the mounting portion (621) of the movable plate (62), so that one worker can quickly install the steel support pressure member (4).

1a: Preceding tunnel 1b: Following tunnel
10: Philaboo 100: The End
11: Rock Bolt 2a: 1st Reinforcement
2b: Second reinforcement 21: Outer flange
22: Inner flange 23: Web
3: Tie bolt 31: Nut
32: Acupressure plate 4: Gangjibo acupressure member
41: Flange 42: Web
5: Shotcrete 6: Supporting member
61: Fixed plate 62: Movable plate
621: Mounting part 63: Angle adjustment member
631: 1st support bar 632: 2nd support bar
633: Coupler

Claims (6)

This relates to a construction method of a close parallel tunnel in which a preceding tunnel (1a) and a succeeding tunnel (1b) are constructed in parallel.
(a) A step of excavating a preceding tunnel (1a);
(b) A step of installing multiple rows of first reinforcement beams (2a) that support the inner surface of the preceding tunnel (1a) at a distance from each other;
(c) A step of constructing a tie bolt (3) by penetrating one side of the excavated preceding tunnel (1a) where the pillar portion (10) is to be formed;
(d) a step of installing a support bearing member (4) on the end of the preceding tunnel (1a) side of the tie bolt (3) so that both ends are supported by the first support beams (2a) on both sides;
(e) A step of pouring shotcrete (5) on the inner surface of the preceding tunnel (1a);
(f) A step of forming the pillar portion (10) between the preceding tunnel (1a) and the subsequent tunnel (1b) by excavating the subsequent tunnel (1b) so that the subsequent tunnel (1b) side end of the tie bolt (3) is exposed;
(g) A step of installing multiple rows of second reinforcement beams (2b) that support the inner surface of the above-mentioned rear tunnel (1b) at a distance from each other;
(h) a step of installing a support bearing member (4) on the end of the rear tunnel (1b) side of the tie bolt (3) so that both ends are supported by the second support beams (2b) on both sides; and
(i) A method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a steel beam, characterized in that it comprises a step of pouring shotcrete (5) on the inner surface of the above-mentioned subsequent tunnel (1b);
In paragraph 1,
A method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening steel beams, characterized in that the first and second steel beams (2a, 2b) are H-shaped steel beams, and the steel beam pressure member (4) is supported on the inner surface of the outer flange (21) of the first and second steel beams (2a, 2b).
In paragraph 2,
A method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening steel beams, characterized in that the above-mentioned steel beam pressure member (4) is composed of a pair of flanges (41) and a web (42) connecting one end of the pair of flanges (41), and the web (42) is supported on the inner surface of the outer flange (21) of the first and second steel beams (2a, 2b).
In paragraph 2,
A method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening steel beams, characterized in that the first and second steel beams (2a, 2b) further include a support member (6) formed in a vertical direction on the front surface so as to be in close contact with the inner surface of the outer flange (21) of the first and second steel beams (2a, 2b) and to support the steel beam support member (4).
In paragraph 4,
A method for constructing a close-contact tunnel using a tie bolt reinforcement system for fastening a steel beam, characterized in that the support member (6) is composed of a fixed plate (61) that is in close contact with the inner surface of the outer flange (21) of the first and second steel beams (2a, 2b), a movable plate (62) that is rotatably connected to the upper or lower end of the fixed plate (61) to support the steel beam pressure member (4), and an angle adjusting member (63) that is provided between the fixed plate (61) and the movable plate (62) to fix the angle of the movable plate (62).
In paragraph 5,
A method for constructing a close-contact tunnel using a steel beam fastening tie bolt reinforcement system, characterized in that a mounting portion (621) on which an end of the steel beam pressure member (4) is mounted is protruded on the front lower portion of the above movable plate (62).