KR101391218B1 - Construction methods of close-twin tunnel by blast shock-controlling and rebar reinforced shotcrete - Google Patents

Construction methods of close-twin tunnel by blast shock-controlling and rebar reinforced shotcrete Download PDF

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Publication number
KR101391218B1
KR101391218B1 KR1020130043638A KR20130043638A KR101391218B1 KR 101391218 B1 KR101391218 B1 KR 101391218B1 KR 1020130043638 A KR1020130043638 A KR 1020130043638A KR 20130043638 A KR20130043638 A KR 20130043638A KR 101391218 B1 KR101391218 B1 KR 101391218B1
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South Korea
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tunnel
pillar
shotcrete
blasting
excavation
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KR1020130043638A
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Korean (ko)
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홍성채
윤경석
강성국
안용관
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주식회사 하이콘엔지니어링
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/01Methods or apparatus for enlarging or restoring the cross-section of tunnels, e.g. by restoring the floor to its original level
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
    • E21D11/105Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
    • E21D11/107Reinforcing elements therefor; Holders for the reinforcing elements
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/006Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries by making use of blasting methods
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42AMMUNITION; BLASTING
    • F42DBLASTING
    • F42D3/00Particular applications of blasting techniques
    • F42D3/04Particular applications of blasting techniques for rock blasting

Abstract

The present invention relates to a highly parallel parallel tunnel construction method which can replace a two-arch tunnel or a large-scale tunnel with a high cost. Conventionally, a parallel tunnel is not practically used because the collapse of the pillar portion The reason for this is that the mechanical excavation method, which does not have much workability by the non blasting method, has to be applied to a considerable part adjacent to the pillar portion due to the concern. Another main reason is that when the rock quality is poor, (Pillar support) technology was not enough.
The present invention relates to a method of converting blast excavation to mechanical excavation near a pillar portion by using a control blasting method using an impact blocking hole and a pillar reinforcing (pillar support) method using a reinforcing-shotcrete, By constructing a pillar-support by shotcrete, it is possible to replace high-cost two-arch tunnels and large-scale tunnels by narrowing the distance between the parallel tunnels at the entrance and exit of tunnels and gradually expanding in the tunnels. And a method of constructing a near parallel tunnel in which a rock pillars are omitted, which can be applied when the rock quality is poor or the tunnel extension is short.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a close-twin tunnel using a shock-

The present invention relates to a method of constructing a near-parallel tunnel excavated by perforation or blasting, and more particularly, to a method of constructing a near-parallel tunnel for securing the stability and economy of a tunnel when the tunnel parallel- Blasting excavation and reinforcement techniques.
More specifically, a method for replacing a monolithic tunnel such as a high-cost two-arch tunnel or a large-scale tunnel with a parallel tunnel is proposed. In this method, the separation distance between the parallel tunnels at the entrance and exit of the tunnels is approached in seconds, And a method for constructing a parallel pillar tunnel construction method by constructing a pillared support in parallel with a tunnel excavation by omitting a rock pillars when the tunnel length is short or the rock quality is poor.

Generally, parallel tunnels installed parallel to each other are arranged so that the distance between two tunnels is 1.5 times or more of the tunnel width to maintain stability.

However, because of the linear condition of the road and the terrain condition, it is necessary to close two tunnels in parallel. In this case, 2-arch tunnel method is mainly used and rarely large tunnel tunnel method is used when rock quality is good .

In the 2-arch tunnel method, since construction of a pilot tunnel and a pillared support structure in the center is performed and the tunnel is excavated, the construction cost and the construction period are excessively required, and there is a problem such as a central leak. In addition, there is a problem in that it is not economical and it is difficult to apply when the rock quality is poor. Therefore, a near parallel tunnel method has been developed to overcome such a problem.

In the near parallel tunnel method, the distance between the two tunnels is excavated by attaching them to each other like a two-arch tunnel, or the tunnel is independently excavated while using a support wall of a rock pillars formed between the two tunnels.

For example, if it is difficult to separate the parallel tunnels of roads in the vicinity of bridges or intersections, or if the length of tunnels is short and the compensation of paper in the tunnel connection section and the overhead construction cost are excessive, Tunnel construction method is necessary.

The following techniques are provided in the conventional near-parallel tunnel method.
Korean Patent Application No. 2006-0003173 (referred to as Prior art 1) describes a 2-arch tunnel method in which a pilot tunnel is omitted. This prior art 1 is for solving the disadvantages of conventional two-arch tunnels, in which a concrete wall (pillar) is formed on one side of a preceding tunnel and then a concrete wall is completed on the other side of the following tunnel. .

However, since the concrete wall is required to be installed at the side of the tunnel after tunnel excavation and the curing period is required, the blasting excavation and the supporting layer installation process of the tunnel are dualized, and the tunnel excavation and the concrete wall can not be simultaneously performed. In addition, since the blast excavation of the trailing tunnel affects the concrete wall, the portion adjacent to the concrete wall is subjected to expensive mechanical excavation, which causes a construction cost to be higher than that of general blasting excavation, and the construction period is also increased.

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Korean Patent Application No. 2006-0021924 (referred to as prior art 2) describes a 2-arch tunneling method. This prior art 2 proposes a two-arch construction method in which a central tunnel (pilot tunnel) and a center wall (central pillar, support) are omitted in a conventional two-arch tunnel.

However, since the countermeasure against blasting excavation is not considered in the trailing tunnel, there is a limit to commercialization of the method as in the prior art 1. In the case of shotcrete, which is a main constituent of the center wall, a general wire mesh or steel fiber is used as a reinforcing material. There is a limitation in strengthening the tensile strength of the wall.

Korean Patent Application No. 10-2004-0046656 (referred to as Prior Art 3) describes a tunnel and a construction method thereof. In this prior art 3, two tunnels are narrowed at the entrance and exit of the tunnel, and a method of gradually widening the tunnel is proposed.

However, since the conventional two-arch tunnel method of installing a central pilot tunnel and a central column is applied to the narrowed entrance and exit of the tunnel and a predetermined distance is secured between the two tunnels, a combination method to be. In the prior art 3, there is a problem in construction due to the limitation of the application of the 2-arch tunnel method having a changed section and the construction of the near parallel tunnel because of the blasting effect and the stability of the pillar portion inevitably.

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Japanese Laid-Open Patent Publication No. 04-350290 (hereinafter referred to as "Conventional Technique 4") describes a method of reinforcing a parabolic reinforcement of a near-parallel tunnel using a tie-bolt or a tie- I am suggesting.

However, the technique of the prior art 4 has a problem in that it is reinforced so as to exhibit the bearing capacity of the rock itself, but when the rock quality is poor or the pillar width is narrow and the bearing capacity of the rock mass itself is insufficient, additional support measures are required.

In the conventional technique used to control the blasting impact, a line drilling method is used to puncture the unloaded ball at intervals of 2 to 4 times of the perforation boundary at the boundary of the pavement surface, Of the tunnel can be blocked. Therefore, there is a limit to prevent the pillar damage in a parallel close tunnel that can replace the 2-arch tunnel.

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Due to the limitations of the related art as described above, when a parallel tunnel needs to be brought close to the tunnel, a two-arch tunnel method or a large-scale tunnel method, which requires a relatively high cost, has been adopted.

The present invention is based on the fact that the near-parallel tunneling method which can replace the high-cost two-arch tunnel or the large-side tunnel has not been put into practical use due to the fear of collapse of the pillar portion in the adjacent tunnel, The construction cost is less than half of the excavation section, and the economical efficiency is lower than that of the 2-arch tunnel.
Another reason is that if the rock quality of the rock pillars is insufficient, the stability of the near-parallel tunnels is insufficient. In addition, the construction technique for constructing the pillars supporting the pillared excavation in parallel with the excavation has not been developed Because.

Therefore, for the practical use of close-coupled tunnels, the technology to convert high-cost mechanical excavation to a low-cost blasting excavation in the near section and the construction of a pillarsupport structure with construction are the main solutions.

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The present invention for solving the above problems is a control blasting method using an impact blocking hole and a method of constructing a close parallel tunnel by reinforcing a pillar portion by a reinforcing bar-shotcrete.
The configuration and contents of the control blasting method of the near parallel tunnel are as follows.
Explosive force of blasting theory is known to propagate to rock mass in the form of compression shock wave and to cause tensile fracture by reflection of shock wave on free surface. Therefore, the method of switching to blasting excavation instead of the conventional machine excavation while preventing collapse of the pillar portion in the close parallel tunnel is as follows: (1) In order to suppress the tensile failure on the free surface, the reinforcement- (2) the installation of the blasting support wall by the shotcrete and (2) the installation of the impact shielding block to block the blasting impact on the interface between the trailing tunnel pillar and the blasting vibration propagating on the preceding tunnel filler surface, sec.) is limited by the control blasting interactions.
With the above three-element construction, it is possible to convert the mechanical excavation area of the conventional trailing tunnel into blasting excavation, and damage to the pillar can be suppressed, thereby ensuring the stability of the nearby tunnel. In particular, the reinforced concrete-shotcrete is reinforced by the non-homogeneous and discontinuous rock pillars with the blasting support wall function of the pillar portion, and is poor in rock quality and is inferior in bearing capacity or in the case of close parallel tunnels where rock pillars are omitted. It replaces a conventional concrete support which requires a long period of curing. Therefore, a pillar support made of reinforced concrete - shotcrete using the sharpening function of shotcrete in parallel with blasting excavation can be constructed. Using the control blasting and pillar reinforcement (pillared support) method, the distance between the tunnels is close enough to replace the 2-arch tunnel or the large-scale tunnel at the entrance and exit of the tunnel, and the proximity using the rock pillars Parallel tunnels can be constructed by omitting the parallel tunnels and rock pillars and constructing a pillarsupport by reinforcing bars - shotcrete.

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The method of constructing the close-coupled tunnel using the impact blocking ball and the reinforcing bar-shotcrete according to the present invention is for placing a parallel tunnel in close proximity to each other due to restriction of entrance and exit paper of a tunnel or a bridge adjacent to the tunnel. Since the process of installing the pilot tunnel or the central column to be applied to the tunnel method is omitted, the construction cost and the construction period are greatly reduced by about 20% or more, and the line and the rear tunnel of the close parallel tunnel are independently formed. The stability is improved and the problem such as the central leak of the 2-arch tunnel is solved.

In addition, it is possible to perform high-cost mechanical excavation with low-cost blasting excavation due to the fear of collapse of the pillar portion in a conventional close-coupled tunnel. In addition, since the separation distance of the parallel tunnels can be narrowed at the entrance and exit of the tunnel, it is possible to reduce the paper size of the ground section compared to the general parallel tunnel, thereby reducing the economic efficiency and the environmental damage.

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BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a view showing a construction sequence of a near-parallel tunnel using an impact-shielding ball and a reinforcing-shotcrete of the present invention and including a rock in a pillar portion. FIG.
FIG. 1B is a view showing a construction sequence of a close-coupled tunnel using a shock-barrier and the reinforced-shotcrete of the present invention and excluding a rock in a pillar portion. FIG.
FIG. 2 is a cross-sectional view showing a state in which an impact blocking hole is formed by slot drilling as a method of constructing an adjacent parallel tunnel using an impact blocking hole and a reinforcing bar-shotcrete according to the present invention.
FIG. 3 is a view showing a state in which a reinforcing bar-shotcrete is installed as an approach parallel tunnel construction method using an impact blocking hole and a reinforcing bar-shotcrete according to the present invention.
FIG. 4A is a cross-sectional view showing the construction of a pillar portion including a rock as a method of constructing a close-coupled tunnel using an impact blocking hole and a reinforcing-shotcrete according to the present invention.
FIG. 4B is a sectional view showing the construction of a pillar portion in which a rock is excluded as a method of constructing a close-coupled tunnel using an impact blocking hole and a reinforcing-shotcrete according to the present invention.
FIG. 5A is a plan view showing a stepwise excavation method of a front and rear tunnel using a pillar portion including a rock, as a method of constructing an adjacent parallel tunnel using the impact blocking hole and the reinforced concrete-shotcrete according to the present invention.
FIG. 5B is a plan view showing a stepwise excavation method of a line-and-post tunnel using a pillar portion in which a rock is excluded as a method of constructing an adjacent parallel tunnel using the impact blocking hole and the reinforcing bar-shotcrete of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a near-parallel tunnel according to the technical idea of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is applicable to a case where a front tunnel 10 and a rear tunnel 20 adjacent to each other in parallel with each other via a pillar 30 including a rock as shown in FIGS. 1A, 2, 3, 4A, The distance between the pillar portion 30 and the pillar portion 30 is narrowed and the distance between the pillar portion 30 and the pillar portion 30 is gradually increased.
To this end, the preceding tunnel 10 and the trailing tunnel 20 are separated from each other and independently constructed. Here, the preceding tunnel 10 means to excavate either the entrance side or the exit side first, Since the trailing tunnel 20 is not excavated, it is installed by general blasting excavation without controlling the blasting vibration.

Next, reinforcing bars are laid out in a lattice form on the inner side of the preceding tunnel 10 formed by blasting and excavation, that is, the portion where the pillar 30 is formed to be in contact with the trailing tunnel 20, and a reinforcing bar- (40). The method of reinforcing the reinforcing bars of the reinforcing bars-shotcrete 40 and the thickness of the shotcrete are determined depending on the quality of the rocky state, the topography and the width of the pillar portion, and the pulling force of the pillar 30 composed of the rock blocks and the shotcrete is strengthened, (20) blasting at the time of blasting, it functions as a supporting wall to prevent damage and collapse of the pillar portion (30), thus functioning as a key to securing the stability of the near parallel tunnel. The reinforcing bars-shotcrete 40 functions as a concrete wall to enhance the stability of the pillar 30 and to provide a pillarsupport function when the strength of the rock is weak or the rock pillars are omitted. The reinforcement-shotcrete 40 may be combined with the tie-bolt 50 described later to further strengthen the binding force of the pillar 30 and to strengthen the local reinforcement of the pillar 30, And the amount of reinforcement (support) to be applied to the entire tunnel periphery due to reinforcement is reduced.

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The tie bolt 50 is installed so as to penetrate the pillar 30 in the direction of the trailing tunnel 20 after the reinforcing bar-shotcrete 40 of the preceding tunnel 10 is installed. Can be selectively installed according to the rock quality and the width of the pillar 30. The construction of the tie bolt (50) is provided in a section where the width of the pillar portion (30) is narrowed to about 5 m as an example. In the section where the width of the pillar portion 30 widens to 5 m or more, a general rock bolt installed around the excavation section can be constructed. The tie bolt 50 is made of reinforcing steel or steel wire and the end protruding toward the rear tunnel 20 is covered with vinyl or the like to facilitate the installation of the pressure plate 70 after the blasting excavation of the rear tunnel 20.

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When the blasting excavation of the preceding tunnel 10, the construction of the reinforcing bars-shotcrete 40, and the construction of the tie bolts 50 are completed, the trailing tunnel 20 is excavated through the following steps.

The front tunnel 10 is excavated in a section where the width of the pillar 30 with respect to the adjacent preceding tunnel 10 is narrowed to less than about 3 to 5 m at the time of blasting excavation of the rear tunnel, This can lead to collapse of the pillar due to the blast of the trailing tunnel.
In addition to the measures for suppressing the collapse of the pillar portion, the reinforcing bar-shotcrete 40 functioning as a blasting support wall in the preceding tunnel pillar portion is replaced with an inexpensive blasting excavation in place of the conventional high cost mechanical excavation in the trailing tunnel 20 An impact blocking hole 60 is formed by slot drilling which completely cuts the excavation interface between the trailing tunnel 20 and the pillar 30 by the method described below.

The excavation of the trailing tunnel 20 is performed by vibration-controlled blasting close to one side of the preceding tunnel 10, and the vibration-controlled blasting is regulated in accordance with the width of the pillar 30, (Vibration velocity reference: 15 cm / sec) so as not to damage the rocks of the reinforcing bars 30 and the reinforcing bars-shotcrete 40 constructed in the preceding tunnels 10.

After the blasting excavation of the imaginary-after-trailing tunnel 20, reinforcing rods are arranged in a lattice form inside the pillar portion 30 of the trailing tunnel 20, and reinforcing bars and shotcrete pouring the shotcrete are installed on the pillar portions 30, .

Finally, a tie plate 70 is installed at the end of the tie bolt 50 installed in the preceding tunnel 10, and a close parallel tunnel using a rock pillars is constructed by applying a predetermined tensile force.

As shown in FIGS. 1B, 2, 3, 4B, and 5B, the present invention is characterized in that a reinforcing rod-shotcrete constructed of a reinforcing rod-shotcrete in which rock pillars are omitted by using the impact blocking hole 60 and the reinforcing- A method of excavation of an adjacent parallel tunnel by a support is presented. In other words, when the tunnel is extended and the tunnel is not linearly widened and the whole section of the tunnel is excavated close to the conventional two-arch tunnel, the reinforcing bars of the reinforcing bars- And a supporting structure of the pillar portion is formed by using the pillar 40 to construct an adjacent parallel tunnel. The supporting structure of the pillar 30 by the reinforcing bars-shotcrete 40 is determined by the method of reinforcing the reinforcing bars and the thickness of the shotcrete to withstand the upper load according to the rock quality and the soil profile around the tunnel, Is structurally advantageous when the wall is vertical, as shown in Figure 5b.

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The method of constructing the near parallel tunnel in which the rock is omitted in the pillar portion is different in that the installation of the tie bolt (50) and the support plate (70) is omitted in comparison with the close parallel tunnel construction method in which the pillar portion includes the rock. The adjacent parallel tunnels in which the pillars 30 are not provided with the rock are adjacent to each other in the front tunnel 10 and the rear tunnel 20, 40 should be prevented from being damaged.

In order to prevent damage to the supporting structure applied to the pillar 30 when the rear tunnel 20 is blasted in the state where the impact blocking hole 60 is formed on the pillar 30 side of the trailing tunnel 20, The separation distance of the pillar 30 is required to be about 2 m due to the tunnel blasting characteristics. Thus, when the blasting excavation of the trailing tunnel 20 is completed, the unexplored portion of about 2 m in width is left on the side of the pillar 30 of the trailing tunnel 20, and the excavated portion is pierced by excavation equipment such as a hydraulic breaker, A partial machine excavation (80) is carried out.

As described above, the method of excavating the near parallel tunnel in which the rock is omitted in the pillar 30 is similar to the approaching parallel tunnel excavation method in which the pillar 30 includes a rock, but the tie bolt 50 and the pressure plate 70 Installation is omitted and partial mechanical excavation 80 is added.

2, the impact blocking hole 60, which is a key element of the present invention, will be described in detail. The distance between the parallel lines and the trailing tunnel, that is, the width of the pillar 30 is within 2 to 3 m When the tunnel is narrowed, a guide tube is attached to a jumbo drill, which is a tunnel drilling equipment. The drilling is performed through slot drilling in which holes having a diameter of Ø76~102 mm larger than that of the blasters are pierced by 20% And on the pillar 30 on the side of the trailing tunnel 20. Since the impact blocking hole 60 can be installed at a rate of 4 to 5 m 2 per hour based on the Ø102 mm perforation and parallel with the perforation of the blast hole, it takes 1 to 2 hours longer to increase the excavation cycle time per excavation The workability is sufficient. In this case, the impact blocking hole 60 may be applied by line drilling in which the width of the pillar portion 30 is widened by 2 to 3 m or more, and the pillar portion is punctured at intervals of 2 to 4 times the piercing diameter from 5 to 6 m from the section . The impact blocking hole 60 prevents the shock in the trailing tunnel 20 from propagating in the direction of the preceding tunnel so that damage to the rock of the pillar 30 and the reinforcing bars and shotcrete 40 of the preceding tunnel 10 And it is possible to reduce the high cost mechanical excavation area conventionally performed in the adjacent trailing tunnel 20 to perform low-cost blasting excavation. In addition, since the impact blocking hole 60 serves as a space (free surface) spaced from the pillar 30 in a partial mechanical excavation 80 adjacent to the pillar 30 on the trailing tunnel 20, Thereby facilitating partial mechanical excavation (80) by hydraulic breakers.

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As shown in FIG. 3, the reinforcing bar-shotcrete 40, which is a pillar reinforcing method, is a key element of the present invention. In detail, the width of the pillar 30 is narrower than the tunnel width A larger amount of stress is concentrated on the pillar 30, so that a stable close-coupled tunnel can be constructed by installing the reinforcing bars-shotcrete 40 on the pillar 30 of the near parallel tunnel. The reinforcement of the reinforcing bars-shotcrete 40 is composed of a vertical reinforcing bar 41 and a horizontal reinforcing bar 42. The reinforcing bars and the spacing between the vertical reinforcing bars 41 and the reinforcing bars 42 are calculated as necessary. As an example, when the reinforcing bars and the reinforcing bars are used for reinforcing the pillars 30, the vertical reinforcing bars 41 having a diameter of 19 mm are spaced at intervals of 10-20 cm and the horizontal reinforcing bars 42 having a diameter of 13 mm are spaced at intervals of 20 to 40 cm It is suitable to arrange the reinforcing bars 30 in the form of a supporting structure of the pillar 30. In general, The reinforcing-shotcrete supports can be built on one side of the preceding tunnel or split on both sides of the tunnel. The method of reinforcing the reinforcing bars before casting shotcrete can be done by assembling the reinforced bars at the installation position or by using reinforced net assembled in advance in a lattice form, and it is possible to install the reinforcing bars within the installation time of the conventional wire mesh. The reinforced concrete-shotcrete 40 has significantly higher tensile strength and flexural strength (about 4 to 6 times) than the generally used shotcrete reinforced with steel fiber or wire mesh, and has substantially the same material properties as the reinforced concrete used for the structure It has the function of sharpening shotcrete with a rapid curing speed and is effective for reinforcing the pillar 30. In addition, since the restraining force of the pillar 30 reinforced by the reinforcing bars-shotcrete 40 is greater than that of the ordinary shotcrete, it is more advantageous in terms of economy and workability than the thickness of the general shotcrete. Particularly, the reinforcing bar-shotcrete 40 formed in the preceding tunnel 10 functions as a blasting supporting wall for suppressing collapse or damage of the rock of the pillar 30 which is weak in tensile force at the time of excavation of the trailing tunnel 20, Together with the impact blocking hole 60 by drilling, functions as a key element in the close parallel tunnel construction method. Another function of the reinforcing-shotcrete 40 is to construct a structure that supports the toe load at the top of the tunnel when the rock quality is poor or the pillar 30 is narrow and the safety of the pillar 30 including the rock is low . Therefore, it is possible to construct a close-parallel tunnel with a support structure of reinforced concrete-shotcrete without rock pillars. Therefore, unlike the 2-arch tunnel, the pillared tunnel and the central pillar are omitted, and the pillared support parallel to the tunnel excavation is constructed using the sharpness characteristics of the shotcrete, so that the construction is superior to the 2-arch tunnel. The reinforcing bars-shotcrete formed in the pillar 30 of the adjacent parallel tunnels can be combined with the conventional tunnel reinforcement method (not shown), rock bolts (not shown), and general shotcrete, It is implemented in parallel.

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Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying drawings. It will be understood that the present invention can be variously modified and changed in accordance with the characteristics of the rock quality, etc. without departing from the scope of the present invention.

10: preceding tunnel 20: trailing tunnel
30: pillar 40: reinforcing bar - shotcrete
41: vertical reinforcement 42: horizontal reinforcement
50: Tie Bolt 60: Shock Absorber
70: Plate 80: Partial excavation
S10: preceding tunnel blasting drilling step
S20: Preliminary Tunnel Reinforcement - Shotcrete Installation Phase
S30: Tie bolt installation step
S40: Step of forming a trailing tunnel impact block
S50: Trailing tunnel excavation step
S60: partial mechanical excavation step
S70: Trailing tunnel reinforcement - shotcrete installation phase
S80: Steps to install the pads

Claims (2)

  1. A method of constructing a close-coupled tunnel using an impact barrier and a reinforcing-shotcrete,
    The distance between the pillars is narrowed at the entrance and exit of the preceding tunnel and the tunnel of the adjacent tunnel in parallel with each other with the pillars including the rocks in between and the spacing distance of the pillars is gradually increased as they enter the tunnel,
    A preceding tunnel blasting excavation step (S10) of blasting and excavating any one of an inlet side and an outlet side of the preceding tunnel;
    A reinforcing bar assembly is installed on the pillar side of the preceding tunnel formed by the blasting excavation and the vertical reinforcing bars and the horizontal reinforcing bars are installed in a lattice form and the shotcrete is installed to strengthen the tension of the pillar portion to suppress the damage of the pillar portion in the trailing tunnel blasting Tunnel reinforcement-shotcrete installation step S20;
    A tie bolt installing step (S30) of inserting a tie bolt made of a reinforcing steel or a steel wire into the rear tunnel side from the front tunnel side in a section where the width of the pillar portion is narrowed to about 5 m;
    In order to prevent damage to the pillar portion during the blasting excavation of the trailing tunnel, the pillar portion between the preceding tunnel and the trailing tunnel is narrowed to less than 3 to 5 m. In the section where the trailing tunnel is formed, The tunnel is continuously drilled in the same direction as the direction of the formation of the trailing tunnel so that the piercing diameter is in the range of 76 to 102 mm while 20% of the piercing hole is superimposed so that the rock is completely formed on the excavation interface between the trailing tunnel and the pillar portion. (S40) forming an impact blocking hole to form an impact blocking hole;
    According to the width of the pillar, the blasting vibration propagating on the pillar surface of the preceding tunnel is within the allowable vibration value which does not damage the shotcrete, and the trailing tunnel which is close to the preceding tunnel by using the vibration controlled blasting, A trailing tunnel blasting and excavating step (S50);
    A step of installing a rear tunnel reinforcing bar-shotcrete (S70) in which a reinforcing bar assembly in which a vertical reinforcing bar and a horizontal reinforcing bar are installed in a lattice form is formed on a pillar portion of a trailing tunnel, and then a shotcrete is installed; And
    And a step (S80) of installing a pressure plate at the end of the tie bolt inserted into the trailing tunnel.
  2. A method of constructing a close-coupled tunnel using an impact barrier and a reinforcing-shotcrete,
    The near-parallel tunnels were constructed by a pillar support constructed of reinforced-shotcrete, omitting the rock pillars,
    A preceding tunnel blasting excavation step (S10) of blasting and excavating any one of an inlet side and an outlet side of the preceding tunnel;
    A reinforcing bar assembly is formed on the pillar side of the preceding tunnel formed by the blasting excavation with a reinforcing bar assembly and a reinforcing bar reinforcing bar which are capable of withstanding the upper load acting in accordance with the rock quality around the tunnel and the toffee, A step of installing a preceding tunnel reinforcing bar-shotcrete (S20) for strengthening the negative tensile force and restraining the damage of the pillars at the time of blasting the rear tunnel;
    In order to prevent damage to the pillar portion during the blasting excavation of the trailing tunnel, an impact blocking hole formed by slot drilling is formed inside the pillar portion where a trailing tunnel is to be formed after completion of the preceding tunnel excavation and reinforcement, A step (S40) of forming an impact blocking hole that completely cuts the excavation interface between the trailing tunnel and the pillar portion by continuous piercing in a state in which 20% of the punched holes are overlapped while piercing the pile hole to a diameter of 76 to 102 mm;
    According to the width of the pillars, excavation of the trailing tunnel near the preceding tunnel is carried out by using the vibration control blasting which is controlled within the allowable vibration value which does not damage the shotcrete, A trailing tunnel blasting and excavating step (S50);
    (S60); a machine tunnel excavation step (S60) of excavating the unexplored portion within 2m of the excavation width left to secure the blasting safety distance adjacent to the pillar portion of the trailing tunnel after the blasting excavation of the trailing tunnel; And
    And a rear tunnel reinforcing bar-shotcrete installation step (S70) of forming a pillarsupporting body capable of withstanding a top toe load by engaging with a pillarsupporting member of the preceding tunnel on a pillar side of a trailing tunnel. A Method of Construction of Close Parallel Tunnel Using Shotcrete.
KR1020130043638A 2013-04-19 2013-04-19 Construction methods of close-twin tunnel by blast shock-controlling and rebar reinforced shotcrete KR101391218B1 (en)

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KR101612527B1 (en) * 2015-10-01 2016-04-14 함정아 Construction method for tunneling
KR101612522B1 (en) * 2015-10-01 2016-04-14 함정아 Construction method for tunneling
KR101648913B1 (en) * 2015-04-02 2016-08-18 주식회사 하이콘엔지니어링 Excavation Method of Narrowed Twin-Tunnel by Blasting
KR101685088B1 (en) * 2016-07-07 2016-12-20 함정아 Construction method for tunneling
CN106884660A (en) * 2017-04-28 2017-06-23 中国矿业大学 A kind of method that protection pillar base angle presplit blasting release controls roadway deformation
KR20190110070A (en) 2019-05-13 2019-09-27 (주)하경엔지니어링 Construction method of close parallel tunnel for excavating and reinforcing tunnel pillar portion according to ground conditions

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KR100438795B1 (en) * 2003-07-31 2004-07-06 (주)현이앤씨 Design method about center wall of three arch tunnel the upside fixing type of lining excavation method
KR100752285B1 (en) * 2006-01-11 2007-08-29 이정재 Construction method for two arches tunnel
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JPH07119548B2 (en) * 1989-12-28 1995-12-20 清水建設株式会社 Reinforcement structure of eyeglass type tunnel
KR100438795B1 (en) * 2003-07-31 2004-07-06 (주)현이앤씨 Design method about center wall of three arch tunnel the upside fixing type of lining excavation method
KR100752285B1 (en) * 2006-01-11 2007-08-29 이정재 Construction method for two arches tunnel
KR20120121640A (en) * 2011-04-27 2012-11-06 주식회사 서영엔지니어링 A Reinforcement Method For Pillar

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101648913B1 (en) * 2015-04-02 2016-08-18 주식회사 하이콘엔지니어링 Excavation Method of Narrowed Twin-Tunnel by Blasting
KR101612527B1 (en) * 2015-10-01 2016-04-14 함정아 Construction method for tunneling
KR101612522B1 (en) * 2015-10-01 2016-04-14 함정아 Construction method for tunneling
KR101685088B1 (en) * 2016-07-07 2016-12-20 함정아 Construction method for tunneling
CN106884660A (en) * 2017-04-28 2017-06-23 中国矿业大学 A kind of method that protection pillar base angle presplit blasting release controls roadway deformation
KR20190110070A (en) 2019-05-13 2019-09-27 (주)하경엔지니어링 Construction method of close parallel tunnel for excavating and reinforcing tunnel pillar portion according to ground conditions

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