KR20180110888A - Construction methods of approaching dual tunnel - Google Patents

Abstract

Disclosed is a method for constructing a parallel tunnel which closely constructs two tunnels so that the ground between two adjacent tunnels acts as a pillar. The method for constructing a parallel tunnel according to the present invention can shorten a construction time and cost, and improve efficiency of construction by improving the construction method so that excavation of a preceding tunnel and a trailing tunnel and work of reinforcing a pillar unit between two tunnels are not interfered with each other.

Description

{Construction methods of approaching dual tunnel}

The present invention relates to a method of constructing a tunnel, and more particularly, to a method of constructing a close-coupled tunnel in which two tunnels are closely installed so that a ground between adjacent two tunnels serves as a pillar.

In the case of a parallel tunnel with two tunnels in parallel, a tunnel is usually installed at a sufficient distance between the tunnel and the tunnel for the structural stability of the tunnel. In this case, to ensure the structural stability of the tunnel, the distance between the separated tunnels is 1.5 times or more based on the tunnel excavation width, though there is a difference depending on the ground condition.

However, it is not easy to secure a distance of 1.5 times or more of the tunnel excavation width due to other conditions such as the terrain condition of the tunnel construction site and environmental problems. In this case, the tunnel is excavated using a two-arched tunnel excavation method in which a central tunnel is first formed at a central portion where two tunnels are to be formed, and a central wall (usually a concrete column) have.

In the arch tunneling method, a central tunnel is first constructed at the central part where two tunnels are to be formed, and then a main tunnel is formed. However, this method is disadvantageous in that the construction is complex, the air is long, and the construction cost is high, by constructing the central tunnel for forming the center wall and then extending the main tunnel in succession.

There is also a construction method in which a large tunnel consisting of one arch is excavated and a column or a wall is formed at the center. However, this construction method requires a column or a wall for efficient ventilation and median separation due to the traffic on the opposite side. Therefore, the width of the tunnel is inevitably widened by more than 1.0 ~ 1.5m compared with the existing 4th tunnel, There is a drawback that it becomes vulnerable.

Thus, a method of reinforcing the pillar portion to allow excavation while maintaining the pillar portion between the tunnel and the tunnel narrower than the tunnel width has been proposed. In this method, reinforcing holes are drilled in the direction of the following tunnel from the preceding tunnel to the trailing tunnel after the preceding tunnel is drilled, grouting is performed after inserting the stiffener, and both ends of the stiffener are fixed to the pillars of each tunnel.

In such a pillar reinforcement method, a reinforcing hole is formed in the front tunnel side and a reinforcing material is inserted and installed so that the other end of the reinforcing material previously installed on the side of the preceding tunnel can be exposed at the time of excavating the rear tunnel, , The stiffener shall be inserted through the reinforcing hole to a length such that one end of the stiffener is located inside the previously planned trailing tunnel excavation line (or line to be excavated).

As a result, it takes a long time to drill due to the long piercing length and requires a long reinforcing material, which raises the construction cost. If the length of the perforation or the stiffener is short, the other end of the stiffener can not be restrained to the trailing tunnel side after the trailing tunnel is excavated. Therefore, a long reinforcing material is used through the reinforcing hole so as to have a length that can be exposed when the trailing tunnel is excavated.

Also, the piercing diameter of the pillar reinforcement is generally larger than the pile diameter of the pile by a jumbo drill used for reinforcing the upper part of the tunnel, or the pile by a drilling machine for drilling a hole to which explosives are loaded for blasting excavation. Therefore, other piercing equipment is used for the pillar reinforcement, and if excavation or reinforcement of the upper ground and pillar reinforcement are performed together, the equipment may interfere with each other in one tunnel and work may be delayed.

In addition, during the grouting work for reinforcement of the pillar, the personnel and equipment of the grouting work team must close the tunnel excavation equipment, so safety problems occur and the excavation work can be stopped. In the preceding tunnel There is a problem in that the stiffener is damaged or damaged by the blasting impact caused by the excavation of the trailing tunnel due to the protruded stiffener than the trailing tunnel excavation surface.

In order to solve this problem, a technology using a coupler for a pillar reinforcement (Korean Patent No. 1,402,267) has been proposed by the same applicant. This is because the first reinforcement member is installed in the pillar portion together with the coupler after the preceding tunnel is excavated and the second reinforcement member is fastened to the coupler already installed in the pillar portion to reinforce the pillar portion.

According to the method proposed in Korean Patent No. 1,402,267, the second reinforcing material is fastened to the coupler of the piled portion in the trailing tunnel side after the trailing tunnel is excavated, so there is no fear of breakage or damage of the reinforcing material at the time of excavating the trailing tunnel. However, additional costs are incurred by using separate parts such as couplers, and delays in operation due to interference between drilling equipment and drilling equipment in the same space remain as a problem.

Korean Registered Patent No. 10-1234814 (registered on March 23, 2013) Korean Registered Patent No. 10-1402267 (Registered on May 26, 2014)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of constructing a close-coupled tunnel which can prevent breakage or damage of a reinforcing member used for reinforcing a pillar portion without using a separate component such as a coupler.

Another problem to be solved by the present invention is to improve the construction method so as not to interfere with the operation of excavating the preceding tunnel and the rear tunnel and the operation of reinforcing the pillar portion between the two tunnels, And a method of constructing a close-coupled tunnel.

According to one embodiment of the present invention as a means for solving the problem,

(a) a preceding tunnel excavation step of excavating the preceding tunnel 1 to a planned depth;

(b) reinforcing the excavation surface of the preceding tunnel, puncturing a plurality of first reinforcing holes in the direction of the trailing tunnel through the pillar surface of the preceding tunnel, inserting the first reinforcing material, and grouting to reinforce the pillar portion, A first stiffener mounting step of installing a first stiffener on the pillar portion so that one end of the first stiffener does not infringe at least the line to be excavated in the trailing tunnel;

(c) a plurality of second reinforcing holes are drilled through the pillar surface in the direction of the trailing tunnel so as not to overlap or intersect with the first reinforcing hole, and one end of the second reinforcing hole is located at least inward A second reinforcing hole puncturing step of puncturing the second reinforcing hole so as to form the second reinforcing hole;

(d) a trailing tunnel excavating the trailing tunnel 2 to a planned depth; And

(e) installing a second reinforcing material to reinforce the excavation surface of the trailing tunnel 2 and to reinforce the pillar portion by inserting the second reinforcing material into the second reinforcing hole exposed in the pillar surface of the trailing tunnel by excavation and grouting, To provide a method of constructing a close-coupled tunnel.

According to another embodiment of the present invention as a means for solving the problem,

(a) a preceding tunnel excavation step of excavating the preceding tunnel 1 to a planned depth;

(b) reinforcing the excavation surface of the preceding tunnel, puncturing a plurality of first reinforcing holes in the direction of the trailing tunnel through the pillar surface of the preceding tunnel, inserting the first reinforcing material, and grouting to reinforce the pillar portion, A first stiffener mounting step of installing a first stiffener on the pillar portion so that one end of the first stiffener does not infringe at least the line to be excavated in the trailing tunnel;

(c) a trailing tunnel excavation step of excavating the trailing tunnel 2 to a planned depth; And

(d) reinforcing the excavation surface of the trailing tunnel (2), puncturing a plurality of second reinforcing holes in the direction of the preceding tunnel through the pillar surface of the trailing tunnel (2) so as not to overlap or intersect with the first reinforcing hole A second reinforcing hole puncturing step of puncturing a second reinforcing hole so that one end of the second reinforcing hole is exposed through at least a pillar surface of the already-tunneled pre-tunnel;

(e) installing a second reinforcing material in the second reinforcing hole and grouting the second reinforcing material to reinforce the pillar portion.

In the embodiment of the present invention and the other embodiments, the reinforcement of the excavation surface of the preceding tunnel and the following tunnel is performed by installing the support material 6 at constant intervals on the excavation surfaces of the tunnels, casting the shotcrete, A plurality of locking bolts can be installed and reinforced.

At this time, the excavation surface may be reinforced by connecting the support material provided on the excavation surface of the preceding tunnel and the rear tunnel with a deformed reinforcing bar or wire mesh, and then injecting shotcrete.

In addition, when the excavated ground of the preceding tunnel and the trailing tunnel is divided into upper and lower halves, a downward stiffener is installed downward at the bottom corner of both sides of the tunnel excavated after the upper half of each tunnel is excavated, And both ends of the upper support material among the support materials may be bound to be fixed.

In this case, when the upper support material is bound to the downward stiffener, it is preferable that the upper support material is bound to the downward stiffener while lifted up by the hydraulic jack so that the upper support material is strongly adhered to the tunnel upper excavation surface.

In addition, a plurality of steel pipes may be installed so as to face the upper ground of the excavation surface through the excavation surfaces of the tunnels, and the excavation surface may be reinforced so as to form a structure in which the support supports the front ends of the steel pipes.

In one embodiment and another embodiment of the present invention, one or more columns of steel pipes are horizontally installed to the upper ground located outside the line to be excavated in the respective tunnels at the start point of the tunnel before the step (a) And forming a gang form by placing the ends of the steel pipes 5 protruding outside the starting point in a state where the ends of the steel pipes 5 are constrained to the frame forming the gang construction.

In one embodiment of the present invention, in the step (b), the end of the first stiffener is fixed to the pillar portion of the preceding tunnel by a support plate and a fixing head, and the opposite end is exposed And can be installed so as to be embedded in the pillar portion.

Also, in an embodiment of the present invention, in order to maintain the shape of the second reinforcing hole without being collapsed due to an external impact in the process of drilling a trailing tunnel through the step (d), the second reinforcement A tubular construction made of PVC or geotextile may be installed in the hall.

Further, in one embodiment and another embodiment of the present invention, after the preceding tunnel and the following tunnel are excavated, the inclined stiffener is inclined upward or downward so as to be embedded in the pillar portion between the two tunnels, It can also be installed.

Preferably, when the pillar spacing between the preceding tunnel and the trailing tunnel is narrow, the boundary between the excavation target portion of each tunnel before each tunnel excavation and the pillar portion is pierced or cut at a certain depth in the tunnel bending direction, And the tunnel may be excavated.

Further, at the time of excavating the preceding tunnel and the subsequent tunnel, the pillar faces of the respective tunnels are further excavated within a range not exceeding the allowable excavation criteria stipulated in the specification, the additional excavated portions are sealed with shotcrete, .

According to the method for constructing a close-proximity tunnel according to the present invention, a plurality of first reinforcing holes are drilled through the pillar surface in the direction of the rear tunnel after the preceding tunnel is excavated, and the first reinforcement is installed. Do not install in length. After the excavation of the preceding tunnel or the trailing tunnel, only the second reinforcement hole is pierced to the pillar portion with the length that can connect the two tunnels, and the reinforcement is reinforced with the second reinforcement after the excavation of the trailing tunnel.

According to such construction, the reinforcement material (first reinforcing material) for reinforcement of the pillar portion is not exposed during the excavation of the trailing tunnel, so that there is no possibility that the reinforcing material is damaged or damaged when the trailing tunnel is excavated. That is, the first reinforcing member and the second reinforcing member are used to sufficiently strengthen the rigidity of the pillar portion, and it is possible to prevent the reinforcing member from being damaged or damaged in the excavation process without using a separate part (ex. Coupler).

In addition, since the reinforcement hole is drilled so as not to exceed the line scheduled to be drilled in the trailing tunnel, the length of the reinforcing member and the length of the perforation can be shortened and the amount of grout used can be reduced, which is advantageous in terms of economy. There is an advantage that the construction period can be greatly shortened because the interference of the reinforcement equipment and thereby the excavation work is not delayed.

1 is a view illustrating a process of reinforcing a pillar portion between a tunnel and a tunnel when a conventional close-coupled tunnel is constructed.
2 is a flowchart of a method of constructing a close-proximity tunnel according to an embodiment of the present invention.
FIGS. 3 to 11 are detailed views of steps according to the method of constructing a close-coupled tunnel according to the present invention.
12 is a flowchart of a method of constructing a close-coupled tunnel according to another embodiment of the present invention.
FIG. 13 is a diagram illustrating the arrangement of various types of equipment when a tunnel is constructed according to the method of constructing a close-coupled tunnel according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

It is to be understood that the terms "comprises", "having", and the like in the specification are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In addition, the terms " part, "" unit," " module, "and the like, which are described in the specification, refer to a unit for processing at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software .

In the following description with reference to the accompanying drawings, the same reference numerals are given to the same constituent elements, and a duplicate description thereof will be omitted. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

FIG. 2 is a view showing a construction sequence of a close-coupled tunnel construction method according to an embodiment of the present invention.

Referring to FIG. 2, a method of constructing a close-proximity tunnel according to an embodiment of the present invention includes a preceding tunnel excavation step S10, a first reinforcing material installation step S20, a second reinforcing hole boring step S30, S40) and a second stiffener mounting step (S50). The first stiffener mounting step S20 may include the step of reinforcing the excavation surface 13 of the preceding tunnel 1 and the second stiffener mounting step S50 may also include the step of mounting the excavation surface 23 of the trailing tunnel 2, And a step of reinforcing the step.

In the construction method according to an embodiment of the present invention, the steps S10 to S30 are repeated along the tunnel advancing direction to form the preceding tunnel 1 to a predetermined depth, and then, through the steps S40 to S50, ) Of the excavation surface and the formation of the trailing tunnel (2) in a shorter time than the construction of the tunnel (2).

3 to 11, a step-by-step process of the close-proximity tunnel construction method according to an embodiment of the present invention will be described in more detail.

The preceding tunnel excavation step S10 is a step of excavating the preceding tunnel 1 to a certain depth from a shank portion serving as an entrance at the time of tunnel excavation. For excavation of the preceding tunnel 1, a general blasting technique can be used. The blasting method is a method widely used in tunnel excavation by drilling a loading hall at intervals of more than one row at the excavation target, charging explosives, and then excavating through blasting.

When the interval between the pillared portions 3 between the planned leading tunnel 1 and the trailing tunnel 2 is small and there is a possibility that the pillar portion 3 is damaged when the tunnel is blasted, (3) by puncturing or cutting the boundary between the pillar portion (3) at a predetermined depth in the tunneling direction to form a shielding line (12) for blocking the blasting shock, thereby transmitting a blasting impact to the pillar portion (Fig. 3 (b)).

In the formation of the shielding line 12, holes are drilled at predetermined intervals along the interface between the part to be excavated and the pillars 3, and wire saws are installed in adjacent holes to form the shielding lines 12 and 22 Method can be applied. Of course, line-drilling or slot-drilling may also be used in which a part of the neighboring holes are punched to overlap each other to form one continuous shield line 12,22.

A process of reinforcing the upper ground of the preceding tunnel (1) before tunneling and forming the gang form (4) can be performed (FIG. 3 (a)). One or more columns of steel pipes 5 are horizontally installed so as to face the direction of advancement of the tunnel on the upper ground outside the line L1 to be excavated in each tunnel at the starting point of the tunnel and the ends of the steel pipes 5 protruding outside the starting point of the tunnel are connected to each other The gangsters (4) can be formed by placing the concrete with the concrete in the restrained state

After the excavation of the preceding tunnel 1, work to reinforce the excavation surface 13 is performed successively (FIG. 4). Arcuate support members 6 corresponding to the shape of the excavated cross section are provided on the excavation face 13 of the preceding tunnel 1 at regular intervals and the shotcrete having a thickness capable of embedding the support members 6 C can be placed to prevent and reinforce the relaxation of the excavation surface.

If the ground is soft, that is, in the case of soft ground, a process of adding a ground reinforcement material such as anchor bolt (8) or anchor in the normal direction to the excavation surface around the excavation surface may be added. In other words, a rock bolt (8) or a ground reinforcement such as anchor may be installed on the excavation surface to prevent rock collapse on the excavation surface and reinforce the ground around the excavation surface.

It is possible to connect the support members 6 provided on the excavation face 13 of the preceding tunnel 1 with the deformed reinforcing bars or the wire meshes 70 at regular intervals and then connect the support members 6 and the deformed reinforcing bars 6, The excavation surface 13 may be reinforced by placing the shotcrete C to a thickness at which the wires can be buried simultaneously (see the detailed view of FIG. 4). Of course, any other known method used for excavation reinforcement can be considered.

The excavated ground (excavation target portion) of the preceding tunnel 1 may be divided into upper and lower halves and excavated separately. In this case, as shown in FIG. 5, a downward stiffener 7 is installed at a bottom edge of both sides of a tunnel excavated after upper-half excavation of the preceding tunnel 1 and downwardly inclined toward the lower ground, Both ends of the upper support member 6A among the support members 6 may be fixed to the upper end of the downward stiffener 7. [

In binding the upper support 6A to the downward stiffener 7, the upper support 6A is firmly fixed to the tunnel upper excavation surface in a tightly tight state, so that the upper support 6A can be firmly fixed It is preferable that the upper support member 6A is engaged with the downward stiffener 7 after adjusting the gap in the state where the upper support member 6A is lifted up by the hydraulic jack.

As shown in FIG. 6, after the tunnel is excavated to a certain depth from the starting point of the tunnel, a plurality of steel pipes 5 installed upward from the excavation end face of the first excavation section (first closure site) Pre-reinforce. Further, the rigidity of the steel pipe 5 exposed through the excavation can be increased by increasing the strength of the tunnel upper load by providing the structure in which the support 6 supports the lower end of the steel pipe 5.

The first stiffener mounting step S20 is a step of reinforcing the pillar portion 3 between the tunnel 1 and the tunnel 2. In the first stiffener mounting step S20, The first reinforcing member 32 may be installed in the direction of the trailing tunnel 2 to reinforce the pillar 3. [ More specifically, a plurality of first reinforcing holes 30 are formed in the direction of the trailing tunnel 2 through the pillar surface 11 of the preceding tunnel 1, the first reinforcing member 32 is inserted, So that the pillar portion 3 can be reinforced.

The pillar portion 3 is preferably reinforced by a pillar portion 3 having a length (D1> D2) such that one end of the first reinforcing member 32 does not invade at least the line L1 to be excavated in the trailing tunnel 2 The first reinforcing hole 30 may be pierced and the first reinforcing member 32 may be inserted and fixed by grouting. That is, the first reinforcing member 32 is installed to a length not to be exposed through the excavation surface at the time of excavating the trailing tunnel 2, and serves as a locking bolt until excavation of the trailing tunnel 2.

A reinforcing hole is formed in the preceding tunnel 1 so that one end of the reinforcing member of the pillar 3 can be exposed through the excavation surface 23 of the trailing tunnel 2 when the trailing tunnel 2 is excavated, Was inserted and fixed by grouting. Therefore, grouting must be performed unnecessarily even in a part removed in the excavation process of the trailing tunnel 2, and there is a possibility that one end of the reinforcing material exposed in the excavation of the trailing tunnel 2 is damaged or damaged in the excavation process.

The present invention is characterized in that one end of the first reinforcing member 32 is provided at a length that does not exceed at least the expected excavation line L1 of the trailing tunnel 2 and then functions as a locking bolt until the additional reinforcing member do. Accordingly, since the reinforcing material is not exposed during the excavation process of the rear tunnel 2 while sufficiently increasing the resistance of the pillar 3, it is possible to prevent the reinforcing material from being damaged or unnecessarily long enough to penetrate the reinforcing hole and grouting.

The first stiffener 32 can be installed horizontally or upwardly or downwardly inclined to the trailing tunnel 2 as required and can be used as a locking bolt after the excavation of the trailing tunnel 2, It is possible to install a plurality of piles in a single excavation section at a predetermined interval in front and back and / or up and down.

One end of the first reinforcing member 32 inserted into the first reinforcing hole 30 and exposed to the pillar surface 11 of the preceding tunnel 1 is connected to the first reinforcing member 32 through the first reinforcing member 32, And the fixing head 39 is used to fix the pillar portion 11 to the pillar portion 11. The other end of the pillar portion 11 is fixed to the trailing tunnel 2 as described above, It is installed so as not to be exposed in excavation but to be embedded in the pillar portion 3.

As the first reinforcing material 32, one of a steel pipe, a strand, a rock bolt, a tie bolt, a reinforcing bar, a micro pile, and a geotextile can be selectively used, and as the filling material for grouting, cement milk, mortar, resin and the like can be used. For filling the filler for grouting, a known pressure grouting method may be used in which the inlet of the first reinforcing hole 30 is caulked and then filled with a filler at a certain pressure.

Excavation of the preceding tunnel 1 by steps S10 and S20 and reinforcement work of the pillar 3 through the first reinforcing material 32 is performed by the excavation of the trailing tunnel 2 in the course of excavation of the trailing tunnel 2, It is repeated to such a depth as not to affect the tunnel 1. Thereafter, a plurality of piles are formed in the direction of the trailing tunnel 2 through the pillar surface 11 of the preceding tunnel 1 so as not to overlap or intersect with the first reinforcing hole 30 from the starting point of the excavated preceding tunnel 1, 2 reinforcing hole 34 is drilled (Fig. 7).

The second reinforcing hole drilling step S30 is performed in the direction of the trailing tunnel 2 through the pillar surface 11 of the preceding tunnel 1 so as not to overlap or cross the first reinforcing hole 30 as described above, The end of the second reinforcing hole 34 opposite to the entrance formed on the pillar surface 11 of the preceding tunnel 1 is pierced at least to the intended excavation line L1 of the trailing tunnel 2, So that the second reinforcing hole 34 can be exposed through the pillar surface 11 when the trailing tunnel 2 is excavated.

The second reinforcing hole 36 is present in a simple hole state until the second reinforcing material 36 is inserted by an external impact such as a blasting shock in the excavation process of the trailing tunnel 2 to be performed after the second reinforcing hole drilling step S30, (34) can not maintain its integrity and can collapse. Therefore, a tubular construction material made of PVC or geosynthetic fiber may be installed in the second reinforcing hole 34 so that the second reinforcing material 36 can be maintained in a perfect shape without collapse before insertion.

The period of the drilling operation for forming the second reinforcing hole 34 may be before the excavation of the trailing tunnel 2 or after the excavation of the trailing tunnel 2, have. In addition, the present invention is not limited to drilling the tunnel 1 only, and it is also possible to work in the direction of the preceding tunnel 1 in the trailing tunnel 2 after the excavation and reinforcement of the trailing tunnel 2, have.

When the drilling operation of the second reinforcing hole 34 is completed, full-scale traverse tunnel 2 is excavated as shown in FIG. The trailing tunnel excavation step S40 is a step of excavating the trailing tunnel 2 to a certain depth from the above-described gang condition 4. The above-described blasting technique can also be used for the excavation of the trailing tunnel 2. Of course, it is not limited to blasting techniques. All excavation methods, including mechanical excavation using dedicated excavation equipment, such as tunnel boring machines, can be included.

In the case where the pillar portion 3 existing between the preceding tunnel 1 and the pillar portion 3 is narrow and the pillar portion 3 may be damaged at the time of blasting excavation, A work for dividing the cutoff line 22 for blocking the blasting impact from being transmitted to the pillar portion 3 side may be performed beforehand by perforating or cutting the boundary between the pillar portions 3 at a predetermined depth in the tunneling direction (Fig. 8 (a)).

In the formation of the shielding line 22, holes are drilled at predetermined intervals along the interface between the part to be excavated and the pillars 3, and wire saws are installed in adjacent holes to form the shielding lines 12 and 22 Can be applied. Line-drilling or slot-drilling may be used in which a portion of the neighboring holes are punched to overlap each other to form one continuous shield line 12,22.

After the excavation of the trailing tunnel 2, as in the case of the preceding tunnel 1, work to reinforce the excavation surface is performed successively (Fig. 9 (a)). Arcuate support members 6 corresponding to the shape of the excavated cross section are provided on the excavation face 23 of the trailing tunnel 2 at regular intervals and the shotcrete having a thickness capable of embedding the support members 6 C can be placed to prevent and reinforce the relaxation of the excavation surface.

In the case of the soft ground, a process of additionally installing a ground reinforcement material such as a rock bolt or anchor in the normal direction to the excavation surface around the excavation surface may be added. In some cases, the excavation surface of the traverse tunnel 2 23 may be connected to each other by a deformed reinforcing bar or a wire mesh 70, and a shotcrete C may be installed to reinforce the excavation surface (see the detailed view of FIG. 4).

Likewise, when the excavated soil (excavation target portion) of the trailing tunnel 2 is divided into upper and lower halves and divided and excavated, it is likewise possible to downwardly slope downward from the bottom edge positions of both sides of the tunnel excavated after the upper half excavation of the rear tunnel 2 The reinforcing member 7 may be provided and both ends of the upper support member 6A among the support members 6 may be fixed to the upper end of the downward stiffener 7 (refer to FIG. 5).

In binding the upper support 6A to the downward stiffener 7, the upper support 6A is firmly fixed to the tunnel upper excavation surface in a tightly tight state, so that the upper support 6A can be firmly fixed The upper support member 6A may be engaged with the downward stiffener 7 after the gap is adjusted with the upper support member 6A lifted up by the hydraulic jack.

After the tunnel is excavated to a certain depth from the starting point of the tunnel, the upper part of the tunnel is previously reinforced with a plurality of steel pipes 5 installed upwards from the excavation end face of the first excavation section (first closure site) The tip of the steel pipe 5 exposed through the excavation may be provided so as to have a structure in which the support 6 supports the lower end of the steel pipe 5 so as to have a sufficient resistance strength to the upper load of the tunnel.

When the reinforcing operation on the excavation surface of the trailing tunnel 2 is completed, a second reinforcing member 36 is installed in the second reinforcing hole 34 already worked on the side of the preceding tunnel 1 as shown in FIG. 9 (b) So that the operation of reinforcing the pillar portion 3 further proceeds (second stiffener mounting step). In the second stiffener installation step S50, the second stiffener 36 is inserted into the second reinforcing hole 34 exposed on the pillar surface 21 of the trailing tunnel 2 by the excavation of the trailing tunnel 2 It can be fixed through a grouting operation.

In fixing the second stiffener 36 to the second reinforcing hole 34 by grouting, pressurized grouting may be used. The second reinforcing member 36 is inserted into the second reinforcing hole 34 and then the inlet and the outlet side of the second reinforcing hole 34 are caulked from the leading tunnel 1 and the trailing tunnel 2 side, The filling material for grout is filled at a predetermined pressure so that the filling material can be evenly filled up to the minute clearance of the second reinforcing hole 34.

The grouting direction may be performed either in the preceding tunnel 1 or in the trailing tunnel 2. Considering the equipment and manpower input situation according to the progress of excavation, either one can be selected appropriately. The second reinforcing material 36 may be one of a steel pipe, a stranded wire, a rock bolt, a tie bolt, a reinforcing bar, a micro pile, and a geotextile fiber, and cement milk, mortar, resin and the like may be used as the filling material for grouting.

According to an embodiment of the present invention, since the second reinforcing member 36 is installed in a state where the preceding tunnel 1 and the following tunnel 2 are excavated, no loss of the stiffener and the grout occurs at all. Further, since the second reinforcing hole 34 is not pierced after the excavation of the trailing tunnel 2 or the reinforcing hole 34 is blocked by the remnant, the second reinforcing hole 34 can be easily formed using a punching machine such as a jumbo drill have.

The positions of the first reinforcing member 32 and the second reinforcing member 36 are not particularly limited. The pillar portion 3 may be arranged in the front-rear direction or in the vertical direction on the basis of the pumping direction according to the ground condition and the planned width. However, it is only required to be located between the support 6 reinforcing each tunnel excavation surface and the support 6. Also, the number of installations is not particularly limited as it is also variable in the ground condition.

In addition, the construction of the tunnel according to one embodiment of the present invention may further include an operation of reinforcing the pillar portion 3 by additionally providing an inclined stiffener 9 as in the example of Fig. 10 . Preferably, an oblique stiffener 9 is provided so as to be inclined upward or downward so as to be embedded in the pillar portion 3 between the two tunnels from the pillar surface 11 of each tunnel to the opposite tunnel after the excavation of each tunnel, 3) can be reinforced.

Another method of doubling the stress of the pillar 3 is to increase the thickness of the shotcrete C as shown in Fig. The pillar surfaces 11 of the respective tunnels are further excavated within the range not exceeding the allowable excavation criterion specified in the specification at the time of excavation of the preceding tunnel 1 and the succeeding tunnel 2 and the excavated portions 13-1, 23-1 may be sealed with the shotcrete C to form the shotcrete C layer thicker than other portions of the pillar portion 3 and the pillar portion 11. [

12 is a flowchart of a method of constructing a close-proximity tunnel according to another embodiment of the present invention.

In the case of the other embodiment of FIG. 12, the steps up to excavation and reinforcement of the preceding tunnel 1 and the step of installing the first stiffener (S20) are the same as those of the above embodiment. The second reinforcing hole 34 is not formed in the trailing tunnel 2 before the second reinforcing hole 34 is drilled but the second reinforcing hole 34 is punched in the direction of the preceding tunnel 1 together with the excavation surface reinforcement after the trailing tunnel 2 is excavated And the second reinforcing member 36 is inserted and fixed by grouting.

That is, unlike the embodiment in which the second reinforcing hole 34 is drilled before the trailing tunnel 2 is excavated, the second reinforcing hole 34 is drilled after the trailing tunnel 2 is excavated, and the second reinforcing hole 34 is formed by press- Except that the drilling operation time for drilling the second reinforcing hole 34 in the entire process is different, as in the case of fixing the second reinforcing hole 36 in the entire process. Therefore, a detailed description of the concrete construction step-by-step will be omitted below.

In the present embodiment, the drilling operation position for drilling the second reinforcing hole 34 is not limited to the one proceeding only from the trailing tunnel 2 side. The work may proceed from the preceding tunnel 1 toward the trailing tunnel 2 after the rear tunnel 2 is excavated to some extent. In other words, one of the two tunnels can be appropriately selected in consideration of the input of equipment and manpower according to the progress of the tunnel excavation.

According to the present invention as described above, since the trailing tunnel is excavated in the state where the preceding tunnel having a considerable depth is formed at the time when the excavation of the trailing tunnel proceeds, When drilling a filler hole with a jumbo drill, a second reinforcement hole can be drilled in the pillar portion with another drilling machine. As a result, the tunnel excavation operation and the drilling operation of the reinforcement hole can be performed without interfering with each other.

In addition, there is an advantage that work can be carried out without any interference between equipment and manpower for installing the second reinforcing material. This is also because the tunnel is formed at a considerable depth already at the time of the excavation of the trailing tunnel due to the construction characteristics.

In the foregoing detailed description of the present invention, only specific embodiments thereof have been described. It is to be understood, however, that the invention is not to be limited to the specific forms thereof, which are to be considered as being limited to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. .

1: preceding tunnel 2: trailing tunnel
3: Pillar 4: Gang Syntax
5: Steel pipe 6: Support material
6A: upper support material 7: downward stiffener
8: Lock bolt 9: Inclined stiffener
10, 20: excavation section 11, 21: pillar section
12, 22: breaking line 13, 23: excavation surface
13-1, 23-1: Additional excavated part
30: first reinforcing hole 32: first reinforcing member
34: second reinforcing hole 36: second reinforcing member
38: Pliers 39: Head
L1: Line to be excavated

Claims (13)

(a) a preceding tunnel excavation step (SlO) for excavating the preceding tunnel 1 to a planned depth;
(b) reinforcing the excavation surface 13 of the preceding tunnel 1 and piercing a plurality of first reinforcing holes 30 in the direction of the trailing tunnel 2 through the pillar surface 11 of the preceding tunnel 1 The first reinforcing member 32 is inserted and then grouted so as to reinforce the pillar 3. The first reinforcing member 32 is formed so that one end of the first reinforcing member 32 does not invade at least the expected excavation line L1 of the trailing tunnel 2 D1> D2) a first stiffener mounting step (S20) of installing a first stiffener (32) on the pillar (3);
(c) a plurality of second reinforcing holes (34) are formed in the direction of the trailing tunnel (2) through the pillar surface (11) so as not to overlap or intersect with the first reinforcing hole (30) A second reinforcing hole drilling step (S30) for puncturing the second reinforcing hole (34) so that one end of the first reinforcing hole (34) is located at least inside of the line (L1) to be excavated of the trailing tunnel (2);
(d) a trailing tunnel excavation step (S40) of excavating the trailing tunnel 2 to a planned depth; And
(e) the excavation surface 23 of the trailing tunnel 2 is reinforced, and the second reinforcing member 36 (not shown) is attached to the second reinforcing hole 34 exposed on the pillar surface 21 of the trailing tunnel 2 by excavation, And a second reinforcing material installation step (S50) of reinforcing the pillar portion (3).
(a) a preceding tunnel excavation step (SlO) for excavating the preceding tunnel 1 to a planned depth;
(b) reinforcing the excavation surface 13 of the preceding tunnel 1 and piercing a plurality of first reinforcing holes 30 in the direction of the trailing tunnel 2 through the pillar surface 11 of the preceding tunnel 1 The first reinforcing member 32 is inserted and then grouted so as to reinforce the pillar 3. The first reinforcing member 32 is formed so that one end of the first reinforcing member 32 does not invade at least the expected excavation line L1 of the trailing tunnel 2 D1> D2) a first stiffener mounting step (S20) of installing a first stiffener (32) on the pillar (3);
(c) a trailing tunnel excavation step (S30) of excavating the trailing tunnel (2) to a planned depth; And
(d) the excavation surface 23 of the trailing tunnel 2 is reinforced so that it does not overlap or intersect with the first reinforcing hole 30, 1 so that one end of the second reinforcing hole 34 is exposed through the pillar surface 11 of the preceding tunnel 1 which has already been excavated. A second reinforcing hole puncturing step (S40) for puncturing the second reinforcing hole (34);
(e) installing a second reinforcing material (36) in the second reinforcing hole (34) and grouting the second reinforcing material (36) to reinforce the pillar portion (3).
3. The method according to claim 1 or 2,
Reinforcing the excavation surface 23 of the preceding tunnel 1 and the trailing tunnel 2,
A plurality of rock bolts 8 are installed in the direction of the normal to the excavation surfaces 13 and 23 by installing the support members 6 on the excavation surfaces 13 and 23 of the respective tunnels at regular intervals and casting the shotcrete C Wherein the reinforcing member is reinforced.
The method of claim 3,
The excavation surfaces 13 and the excavation surfaces 13 are formed by connecting the support material 6 provided on the excavation surface 23 of the preceding tunnel 1 and the trailing tunnel 2 with a deformed reinforcing bar or a wire mesh 70, 23) is reinforced.
The method of claim 3,
When the excavated ground of the preceding tunnel 1 and the trailing tunnel 2 is divided into upper and lower halves, the downward stiffener 7 is installed downward at the bottom edge positions of both sides of the tunnel excavated after the upper half of each tunnel is excavated , And both end portions of the upper support material (6A) of the support material (6) are fastened and fixed to the upper end of the downward stiffener (7).
6. The method of claim 5,
Characterized in that when the upper support member 6A is fastened to the downward stiffener 7, the upper support member 6A is fastened to the downward stiffener 7 while being lifted up by the hydraulic jack so that the upper support member 6A tightly contacts the tunnel upper half excavation surface Construction method of close - coupled tunnel.
The method of claim 3,
A plurality of steel pipes 5 are installed so as to face the upper ground of the excavation face through the excavation surfaces of the tunnels so as to be inclined upwards so that the support 6 supports the front end of the steel pipe 5, 13, 23) are reinforced.
3. The method according to claim 1 or 2,
Before the step (a)
One or more columns of steel pipes 5 are horizontally installed so as to face the tunneling direction of the tunnel on the upper ground on the outer side of the line L1 to be excavated in each tunnel at the starting point of the tunnel,
Wherein the gangway structure (4) is formed by placing concrete at the ends of steel pipes (5) protruding outside the starting point of the tunnel, with the concrete being restrained to the frame forming the gang construction.
3. The method according to claim 1 or 2,
In the step (b)
The end of the first reinforcing member 32 is fixed to the pillar surface 11 of the preceding tunnel 1 by the support plate 38 and the fixing head 39 and the opposite end is not exposed at the time of excavating the trailing tunnel 2 And the pillar portion (3) is installed so as to be embedded in the pillar portion (3).
The method according to claim 1,
The second reinforcing hole 34 is formed immediately after the step (c) so that the second reinforcing hole 34 can be maintained without being collapsed due to an external impact during the excavation process of the trailing tunnel 2 through the step (d) Wherein the tubular structure is made of PVC or geosynthetics.
3. The method according to claim 1 or 2,
The inclined stiffeners (1, 2) are inclined upward or downward so as to be embedded in the pillar portions (3) between the two tunnels toward the opposite directional tunnels at the pillar surfaces (11, 21) of the respective tunnels after the excavation of the preceding tunnel 9. The method of claim 1,
3. The method according to claim 1 or 2,
When the interval between the pillar portions 3 between the preceding tunnel 1 and the trailing tunnel 2 is narrow, the boundary between the excavation target portion of each tunnel before each tunnel excavation and the pillar portion 3 is constant (12, 22) for cutting off a blast shock by drilling or cutting the tunnel after the tunnel is drilled.
3. The method according to claim 1 or 2,
The pilasters 11 of the respective tunnels are further excavated within the range not exceeding the allowable excavation criteria stipulated in the specifications at the time of excavation of the preceding tunnel 1 and the succeeding tunnel 2 and the excavated portions 13-1 , 23-1) are sealed with shotcrete (C) to reinforce the pillars (3) and the pillars (11).

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