KR20170087786A

KR20170087786A - Reinforcement method of Tunnel

Info

Publication number: KR20170087786A
Application number: KR1020160007809A
Authority: KR
Inventors: 이평우; 이상원
Original assignee: 이평우; 이상원; 주식회사 성우사면
Priority date: 2016-01-21
Filing date: 2016-01-21
Publication date: 2017-07-31

Abstract

A tunnel reinforcement method is disclosed. The tunnel reinforcement method according to the present invention reinforces a tunnel by reinforcing the upper part of a tunnel excavation surface to be excavated in advance by a steel pipe reinforcing material, then excavating the tunnel to a planned depth, installing a steel beam on the excavation surface, and installing a shotcrete A drilling step of forming a perforation hole inclined upwards from the excavation end face of the excavation soil toward the upper part to be excavated; a grouting step of reinforcing the pore wall by fixing the steel pipe reinforcement to the perforation hole by inserting the steel pipe reinforcement into the perforation hole and grouting; A step of installing a steel girder beam to install a steel beam on the excavation surface after excavating the excavation ground in a planned stepwise depth from the section, and a step of casting a shotcrete to reinforce the excavation surface by arranging the shotcrete to a thickness such that the steel girder can be embedded In the piercing step, the steel of the Nth excavation ground from the excavation section Beam spot over the top of it by the trench cross-section and the N-th beam Kang Ji least one or more beam spot exists, Kang Ji perforated base up to the perforations so as to pass through between that spot.

Description

{Reinforcement method of Tunnel}

The present invention relates to a tunnel reinforcement method, and more particularly, to a tunnel reinforcement method in which an upper half of a ground to be excavated is reinforced in advance by using steel pipe grouting so as to prevent ground collapse or displacement during excavation.

In tunnel construction, steel pipe grouting method using steel pipe type reinforcement is generally used for reinforcing the upper ground of excavation surface. This is an effective method for reinforcing the tunnel which is widely used when excavating tunnels on soft ground. It is an effective method to prevent ground collapse or displacement in the excavation process by pre-strengthening the excavated area before excavation.

In tunnel reinforcement using steel pipe grouting, generally, the vicinity of the upper half of the excavation surface is drilled in the longitudinal direction of the tunnel, a steel pipe reinforcing material is installed in the hole by perforation, and the steel pipe reinforcing material, steel pipe reinforcing material, And the inside of the ground around the perforation hole wall is reinforced by the upper grooves of the excavation surface by pressure grouting.

The drilling is carried out using a dedicated drilling rig equipped with a drill bit. After inserting the steel pipe stiffener into the drilling hole, the drilling hole entrance is caulked using a caulking bag or quick-setting material. Then, the grout material is injected through the grout hose in a pressurized manner, thereby increasing the tensile strength around the ground to be excavated so as to strengthen the shear resistance.

On the other hand, the NATM method (New Austrian Tunneling Method), which is generally used for tunnel excavation, is a method in which an H beam or an angled support beam is installed immediately on the excavated free surface (excavation surface) The excavation site is reinforced by placing the shotcrete with a certain thickness around it, and the excavation surface is stabilized.

When reinforcing the upper half of the tunnel with the steel pipe grouting by tunneling using this NATM method, one end of the steel pipe reinforcement installed upward at a predetermined angle to the excavation face upper ground (the rear end with reference to the tunneling direction) The reinforcement effect can be maximized.

Length, spacing, and angle of the steel pipe to be installed during the grouting of the steel pipe are determined within the appropriate range of the circumference of the tunnel considering the ground condition or the lipid in the tunnel design stage. The length is reduced and the reinforcing effect is lowered).

However, due to the interference between the drifter and the steel girder of the drilling equipment and the length of the steel pipe itself, the steel pipe proposed in the design is installed due to the field conditions in which the work should be performed in a limited space in performing the steel pipe grouting for the excavation- There is a problem that it is difficult to apply the angle (5 DEG to 20 DEG) as it is.

In order to comply with this, it is necessary to construct a cross-sectional type as shown in Figs. 1A and 1B in accordance with the installation angle of the steel pipe reinforcement at each planned excavation depth. However, The tunnel must be excavated while changing it, so that the air is lengthened and the construction cost is increased.

In addition, since the size of the steel girder 210 to be installed at regular intervals in the tunnel excavation direction must be changed, a lot of expenses are required to manufacture the steel girder, and the curved excavation section, which is excavated at the end after the completion of the excavation, (300), the consumption of unnecessarily consumed material is large.

Therefore, in order to reduce the construction cost and simplify the process, the excavation and reinforcement are not generally performed, but the excavated ground is excavated at the planned depth at once, then the steel beam is installed on the excavated surface and the steel pipe grouting is performed. In order to limit the installation angle of the steel pipe.

In FIGS. 1A and 1B, reference numeral 100 denotes a digging tunnel, and reference numerals 102 and 130 indicate caulking means for sealing the perforation hole and the perforation hole inlet.

Korean Patent Registration No. 10-1234814 (Registered on March 2, 2013)

A problem to be solved by the present invention is to provide a method of drilling a steel pipe before drilling at a surface (excavation section) at an intermediate position by advancing a drilling point for installing a steel pipe reinforcement before reaching a ground to be excavated, To provide a tunnel reinforcement method capable of grouting steel pipe for reinforcement above a tunnel excavation surface at a steel pipe installation angle (5 ° to 20 °) proposed in the design.

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

A tunnel reinforcement method for reinforcing a tunnel by reinforcing an upper part of a tunnel excavation surface to be excavated with a steel pipe reinforcing material, excavating the tunnel to a planned depth, installing a strong beam and a shotcrete on the excavation surface,

A perforation step of forming a perforation hole inclined upward from an excavation end face of the excavated soil toward an upper part of the ground to be excavated;

A grouting step of inserting a steel pipe reinforcing material into the hole and grouting the steel pipe reinforcing material to fix the steel pipe reinforcing material to the hole and reinforcing the steel wall;

Excavating the excavated ground from the excavated section to a planned step depth;

A steel beam installation step in which a steel beam is installed on the excavation surface; And

And a shotcrete pouring step of pouring the shotcrete to a thickness at which the steel girder can be embedded, thereby reinforcing and arranging the excavation surface,

Wherein the drilling is performed such that the drilled hole passes through the upper edge of the N-th excavation site from the excavation section and passes through at least one edge of the steel girder between the excavation section and the N-th steel girder. The present invention provides a method of reinforcing a tunnel.

Here, a part of the preceding steel pipe reinforcement already installed on the excavating ground and the part of the Nth steel pipe reinforcement which is installed in the perforation hole passing the upper part of the Nth steel pipe supporting part of the ground to be excavated and supported by the Nth steel pipe supporting part is overlapped, It is preferable that the Nth precipitation site be positioned.

In addition, when forming the perforation hole on the ground to be excavated, the steel pipe stiffener may be inserted into the perforation hole by a direct hole drilling method in which the steel pipe stiffener is pushed into the perforation hole at the same time as the drilling.

The steel pipe reinforcing member may be a main stiffener and an auxiliary stiffener connected in a straight line. The auxiliary stiffener may be inserted into the perforation hole together with the main stiffener. When the main stiffener is inserted up to a predetermined position, It is preferable that only the main stiffener inserted in a predetermined position of the hole is fixed by grouting.

At this time, it is preferable that one end of the main reinforcement is positioned in the perforation hole above the Nth steel girder beam spot.

Preferably, the main stiffener and the auxiliary stiffener are connected to each other through a hole-holding tube which surrounds and connects the opposing side ends of the two stiffeners, or the side end portions facing each other are connected to each other in a screwed manner, or the main stiffener and the auxiliary stiffener It is preferable to form a notch in the circumferential direction at the boundary between the two stiffeners so that the auxiliary stiffener can be easily removed from the main stiffener.

As another example, one or more of the notches may be formed in the longitudinal direction of the auxiliary stiffener so that the auxiliary stiffeners, which are slightly exposed at the time of tunnel excavation, may be sequentially cut.

The main stiffener may include a plurality of injection holes for discharging the grout material to the outside, and the injection holes may be formed spirally around the main stiffener to prevent the flexural rigidity from being deteriorated.

In the grouting step, grouting can be performed by a simultaneous pressure grouting method using a plurality of grout hoses having different lengths and an air vent hose for air discharge.

At the same time, the simultaneous pressurized grouting is performed such that a plurality of grout hoses and air vent hoses are extended out of the perforation holes from the front end of the steel pipe reinforcement member, while the grout hoses extending out of the perforation holes are connected to the grout pump and the air vent valve of the air vent hose is opened Installing hoses; A perforation hole sealing step for sealing an inlet of the perforation hole; Filling the grout material between the steel pipe reinforcement and the steel pipe reinforcement through the grout hose connected to the grout pump; And a grouting step in which the air vent valve of the air vent hose is closed when the grout material is ejected through the air vent hose so as to grout the grout material so as to fill the grout material through the perforation hole to a uniform pressure throughout the ground.

As another example, in the grouting step, the grouting may be performed by a multi-stage pressure grouting method in which the grout hose with the shrinkable / expandable packer is moved from the end of the perforation hole to the perforation hole entrance side in a stepwise manner.

In addition, after excavating the excavation site at the planned depth of the excavation, the excavation surface side where the steel pipe stiffener is not installed and the excavation surface using the selected one of the rock bolts, tie bolts, and steel pipes in the normal direction of the excavation surface, And a step of installing the reinforcement material.

According to the tunnel reinforcement method according to the embodiment of the present invention, before reaching the ground to be excavated, the drilling point for installing the steel pipe reinforcement is advanced, and the steel pipe is grouted at the intermediate surface (drilling section) By performing excavation step by step up to the ground, it is possible to grouting steel pipe for reinforcement above the tunnel excavation surface with steel pipe installation angle (5˚ ~ 20˚) suggested in the design.

In addition, by separating the steel pipe stiffener into a main stiffener and an auxiliary stiffener acting as a push rod, the auxiliary stiffener, which serves as a push rod, can be separated and removed after inserting the main stiffener to the planned position, There is no need for additional work for cutting the exposed steel pipe reinforcement in the process of excavating the steel pipe.

FIGS. 1A and 1B are an enlarged view of a construction state and a substantial part showing a steel pipe grouting method according to the prior art of a cross-sectional system.
2 is a block diagram of a tunnel reinforcement method according to the present invention;
FIGS. 3 to 14 are detailed views of steps of the tunnel reinforcement method according to the present invention.
15 is a view showing various embodiments of a steel pipe stiffener applied to a tunnel reinforcement method according to the present invention.
16 is a view showing another embodiment of a steel pipe stiffener applied to a tunnel reinforcement method according to the present invention.
17 is a view showing still another embodiment of a steel pipe reinforcement applied to a tunnel reinforcement method according to the present invention.
18 is a view showing still another embodiment of a steel pipe reinforcement applied to a tunnel reinforcement method according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the present invention, a detailed description of known configurations will be omitted, and a detailed description of configurations that may unnecessarily obscure the gist of the present invention will be omitted. The same reference numerals are given to the same constituent elements.

In the present invention, the upper part of a tunnel excavation surface to be excavated is reinforced with steel pipe grouting using a steel pipe reinforcing material in advance, then the tunnel is excavated to a predetermined depth, a steel girder beam installation and a shotcrete are installed on the excavation face to reinforce the tunnel, We propose a new method that can satisfy the steel pipe installation angle (5˚ ~ 20˚, θ) suggested in the design for reinforcement by grouting in advance.

Specifically, prior to reaching the site to be excavated, the perforation point for installing the steel pipe reinforcement is advanced to drill the pipe surface (excavation section) at the intermediate position, and the steel pipe grouting is performed first. We propose a reinforcing method that can reinforce the upper part of the tunnel excavation surface by performing steel pipe grouting with the proposed steel pipe installation angle (5˚ ~ 20˚).

2 is a block diagram of a tunnel reinforcement method according to the present invention. The tunnel reinforcement method proposed by the present invention will be schematically described first.

Referring to FIG. 2, the method of reinforcing a tunnel according to the present invention includes a drilling step (S10), a grouting step (S20), a drilling step (S30), a steel beam installation step (S40), and a shotcrete pouring step (S50) And a support material mounting step (S45) for reinforcing the excavation surface by using the support material (45) before and after the steel girder beam installation.

The drilling step S10 is a step of forming a perforation hole H upwardly inclined from the excavation end face of the excavated ground where the excavation has already been performed toward the upper part to be excavated. In the perforating step S10, a perforating machine such as a jumbo drill or a crawler drill is used. At this time, by using a known direct drilling method in which the steel pipe stiffener 20 is pushed together with the perforation, the steel pipe stiffener 20 is inserted separately after drilling The process may be omitted.

(N-1) existing at least one between the excavation section and the Nth precipitation site passing over the Nth excavation site (N) of the Nth excavation planned ground from the excavation section in drilling the perforation hole (H) The steel pipe reinforcing member 20 satisfying the steel pipe installation angle (5 ° to 20 °, θ) proposed in the design can be constructed (see FIG. 3 to be described later) .

For example, considering the overlapping distance of the front and rear steel pipe stiffeners 20 and the gap between the steel strips (which is not specified because it depends on the ground condition), a second excavated ground (N-1) of the ground to be excavated in the final excavation section (A) and the first (N-1) of the excavation target ground in the case where the front end of the rear steel pipe stiffener (20-2) And the perforation hole (H) center axis passing through the upper part of the second piercing hole (N).

As a result, if the virtual straight line passing through the first steel girder beam (N-1) and the second steel beam beam (N) of the excavation target ground in the final excavation cross section is aligned with the axial center of the hole H, (20-2) can be installed at the steel pipe installation angle (5˚ ~ 20˚) suggested in the design while satisfying the structure that is supported on the second steel girder beam after the stepwise excavation.

The spacing of the steel girder 40 may vary depending on the number of excavation sections to be excavated in the tunnel design process according to the ground condition, and the steel pipe reinforcement 20-1, 20-2 must consider the minimum overlap distance between the two stiffeners, the number of the stiffeners 40 installed between them may be different.

As a result, the steel girder N, which supports the front end of the rear steel pipe stiffener 20-2 located relatively behind, is not limited to the specific excavation target ground from the excavation end face (N-1) between the excavation cross-section (A) and the Nth precipitation site (N) to satisfy the range of angles (5˚ to 20˚) One must exist.

That is, at least one steel girder should be located between the steel girder N where the leading end of the steel pipe reinforcement 20-2 is to be supported and the excavating end. For this, at least a second excavation The steel strip supporting member 20-2 is provided with a steel strip supporting member so that the steel strip supporting member can support the leading end of the steel strip reinforcing member 20-2.

After the perforation is completed, the steel pipe stiffener 20 is inserted into the perforation hole H and grouting is performed to fix the steel pipe stiffener 20 to the perforation hole H and grouting is performed to reinforce the steel wall (grouting step S20, 11).

As described above, the insertion of the steel pipe stiffener 20 before grouting can be performed by a known straight drilling method in which the perforation and the steel pipe stiffener 20 are simultaneously inserted, so that the process of inserting the steel pipe stiffener 20 can be omitted.

The steel pipe stiffener 20 to be inserted into the perforation hole H may have a structure in which a detachable main stiffener 22 and an auxiliary stiffener 24 are connected in a straight line. In this case, the auxiliary stiffener 24 may be connected to the main stiffener 22 The main stiffener 22 is inserted into the perforation hole H so as to be separated from the main stiffener 22 and removed so that the main stiffener 22 inserted in a predetermined position of the perforation hole H ) Can be fixed by grouting.

The auxiliary stiffener 24 is inserted into the perforation hole H together with the main stiffener 22. The main stiffener 22 is inserted to the predetermined position and then removed from the main stiffener 22 and removed from the perforation hole H. It is possible to eliminate the inconvenience of stepwise cutting the steel pipe reinforcing member 20, which is slightly exposed in the process of excavating the ground to be excavated thereafter, and it is effective in shortening the air and reducing the construction cost.

In the grouting step S20, a plurality of grout hoses 26 having different lengths, an interval material 27 dividing the internal space of the steel pipe, air vent hoses 28 for air discharge, A known multi-stage pressure grouting method in which the grout hose 26 with the expandable packer is grooved while moving the grout hose 26 from the deepest hole to the perforation hole H side stepwise can be adopted.

The excavation step S30 is a step of excavating the ground to be excavated from the excavation end face A to the planned step depth after completion of the excavation upper ground reinforcement through press grouting (refer to FIG. 12). Depending on the ground condition, excavation depth can be derived from the design based on the ground condition and considering the upper ground load, and excavation can be applied to all known excavation methods such as excavation using excavation equipment or excavation equipment depending on the ground condition.

After the excavation is completed through the planned depth and shape through the excavation, the steel beam 40 is installed on the excavation surface to prevent deformation of the excavation surface and to reinforce the structural rigidity. In the subsequent step of casting the shotcrete S50) is a step of reinforcing and arranging the excavation surface so as to minimize the relaxation of the ground surface by pouring the shotcrete 50 into the thickness to which the steel girder 40 can be buried.

An excavation surface side portion in which the steel pipe reinforcing member 20 is not installed before and after the step S40 of installing the steel girder beam and a support 45 in the direction of the normal to the excavation surface such as a rock bolt, a tie bolt, a nail, (Step S45) of reinforcing and stabilizing the excavation surface by using the support material.

At this time, the support material (45) is to withstand the ground load at the upper part of the tunnel.

Hereinafter, a tunnel reinforcement method according to the present invention will be described in more detail with reference to the detailed construction diagrams of FIG. 3 through FIG. As shown in the example of Fig. 3, when the strong nose spot N supporting the front end of the rear steel pipe stiffener 20-2 is located on the second excavation target ground from the excavation end face A The reinforcing method according to the present invention will be described.

In the piercing step S10, a perforation hole H is formed upward from the excavation end face A of the excavation site where the excavation has been performed toward the upper part of the ground to be excavated. The drilling is performed by using a drilling machine 110 such as a jumbo drill or a crawler drill equipped with a drilling rod 114 having a drill bit 112 at the tip thereof and a direct drilling method in which the steel pipe stiffener 20 is pushed together with the drilling The process of inserting the separate steel pipe stiffener 20 may be omitted.

As shown in Fig. 4, when the perforation hole H is formed, the perforation hole H extends from the excavation end face A to the upper edge N of the second excavation site B2, (H) between the first excavation site (B1) and the second excavation site (N-1) between the first excavation site (N) and the second excavation site (N). Though there is a slight difference in excavation depth, the drilling angle is in the range of angles proposed by the design (5˚ ~ 20˚).

When the drilling is completed, the steel pipe stiffener 20 is inserted into the hole H as shown in Fig. The steel pipe stiffener 20 to be inserted into the perforation hole H may be integrally formed. However, if the steel pipe reinforcement 20 is integrally formed, it is troublesome to cut the portion exposed from the ground top to be excavated in a subsequent excavation step S30 . Therefore, it is preferable that the auxiliary stiffener 24 and the main stiffener 22 are connected in a straight line so that they can be separated later as shown in Fig.

In this case, the auxiliary stiffener 24 is inserted into the perforation hole H together with the main stiffener 22 and then separated from the main stiffener 22 and removed from the perforation hole H, So that the grout hose 26 and the air vent hose 28 can be easily inserted into the main reinforcement 22 in the subsequent pressure grouting step S20 do.

The main stiffener 22 is supplied through the grout hose 26 in the press grouting step S20 to be described later so that the grout material to be filled therein is smoothly discharged from the main reinforcement 22 to the wall surface of the perforation hole H The injection holes are formed spirally around the main stiffener 22 so that the bending stiffness of the main stiffener 22 is not lowered by the injection holes.

The connection between the main reinforcement 22 and the auxiliary reinforcement 24 can be achieved by simply taping the joint ends of the two stiffeners as shown in various examples in Fig. 15 (a), forming screw threads on the opposing side ends, (B, c) can be considered. Also, various methods such as a method of inserting fittings into the joints as shown in Fig. 16 may be considered.

17, the main stiffener 22 and the auxiliary stiffener 24 are integrally formed, and a notch 200 continuous in the circumferential direction is formed at the boundary between the main stiffener 22 and the auxiliary stiffener 24. [ The notch 200 is broken when the impact is applied to the auxiliary stiffener 24 exposed in the excavation process so that the auxiliary stiffener 24 can be easily separated from the main stiffener 22 and removed .

At this time, one or more notches may be formed in the longitudinal direction of the auxiliary stiffener 24 as shown in the example of b, so that the auxiliary stiffeners 24, which are slightly exposed at the time of excavation stepwise according to the planned depth, .

As shown in the example of Fig. 18, a method of using the hole retaining pipe 210 to connect the opposing side ends of the two stiffeners at the same time may be considered. In this case, after inserting the main stiffener 22, the auxiliary stiffener 24 acting as a pusher from the hole holding pipe 210 may be separated and removed from the perforation hole H, and the hole holding pipe 210 may be removed from the main stiffener 22 ) In the perforation hole (H).

At this time, the auxiliary stiffener 24 serving as a push rod must be longer than the hole holding pipe 210 and should be made of a rigid material so that the main stiffener can be pushed to the second steel bead position, There is no particular limitation on the material selection as long as a minimum space is secured between the hole retaining pipes even if the entrance of the hole H is collapsed and only the rigidity is enough to carry out the grouting.

Since the main reinforcement 22 is required to bear the ground load on the tunnel excavation surface together with the steel girder 40, it is preferable to use a steel pipe having a high rigidity. However, Etc., or may be used in parallel with these.

Of course, the present invention is not limited to the connection structure illustrated in the drawings, but may be a structure in which the auxiliary stiffener 24 can be removed from the main stiffener 22 after insertion of the main stiffener 22 to a predetermined position. It will thus be appreciated that not only all types of connection structures or methods known in the art, but also any connection structure or method from which those skilled in the art can readily appreciate, may be included.

The auxiliary stiffener 24 is inserted into the perforation hole H together with the main stiffener 22. The main stiffener 22 is inserted up to the predetermined position and then separated from the main stiffener 22 and removed from the perforation hole H. [ It is possible to eliminate the inconvenience of stepwise cutting the steel pipe reinforcing member 20, which is slightly exposed in the process of excavating the excavated ground, and it is advantageous in shortening the air and reducing the construction cost.

After the steel pipe stiffener 20 is inserted into the hole H, the grout hose 26 and the air vent hose 28 are installed in the steel pipe stiffener 20 as a preparation step for the grouting, as shown in Fig. The grout hose 26 may be provided with a plurality of grout hoses 26 having different lengths and may be divided into a plurality of grout hoses 26 by using a gap 27 so that the main entrance of each grout hose 26 is located in another area You may.

Of course, when grouting is performed by a known multi-stage pressure grouting method in which grouting is performed while moving grout hoses with shrinkable / expandable packers from the end of the perforation holes stepwise toward the perforation hole entrance side, grouting is carried out with a packer around the end- By simply placing the grout hose at the end of the perforation hole, the preparation for grouting can be completed (not shown).

After the grout hose 26 and the air vent hose 28 are installed for grouting, the auxiliary stiffener 24 is removed from the main stiffener 22 as shown in Fig. 7, and the grout hoses 26 ) And the air vent hose (28) and the perforation hole (H) inlet wall by appropriate means.

The sealing of the opening of the perforation hole H is performed by a method using a quick-setting agent 29 or a foaming agent, a method of using a caulking bag which expands due to an external pressure and the circumferential surface is brought into close contact with the inlet hole wall of the perforation hole H, (Not shown), a method of using a tubular adapter having a grout hose and a plurality of through holes for guiding the grouting hose and the air vent hose to extend to the main reinforcement without being folded in the middle, together with the caulking bag.

When a caulking bag is provided at one end of the tubular adapter facing the tip of the main reinforcement 22 and the perforation hole H when the perforation hole H is closed by using the tubular adapter and the caulking bag together, It is possible to place the caulking bag at a position close to the main reinforcement 22 at the time of mounting and to prevent the grout material from being unnecessarily filled up to the portion to be removed by subsequent excavation (the perforation hole between the perforation hole entrance and the caulking pouch) .

The grout hose 26 extending outside the perforation hole H is connected to the grout pump P provided outside the perforation hole H and is connected to an air vent valve (not shown) provided in the air vent hose 28 outside the perforation hole H. [ 280 are opened (FIG. 9). Grout material is filled between the steel pipe reinforcing member 20 and the steel pipe reinforcing member 20 through the grout hose 26 connected to the grout pump P (FIG. 10).

The grout material 290 is filled in the main reinforcement 22 and the perforation hole H so that the air existing in the space is discharged through the air vent hose 28 out of the perforation hole H, Is filled with the grout material, grout material is ejected through the air vent hose (28). When the grout material is ejected, the air vent valve (see FIG. 9) is closed, and the grout material 290 is subjected to pressurized grouting so that the grout material H can be filled with uniform pressure to the ground through the hole H.

If the grout material 290 is filled without the air vent hose 28, the grout material 290 is not filled with the grout material 290, The grout may be deteriorated in quality. As a result, even if the ground is reinforced through grouting, the reinforcing portion can not have sufficient rigidity to withstand the ground load. Therefore, the air vent hose 28 must be used.

After grouting, the grout hose is closed and separated from the pump so that the grout material is sufficiently cured (Fig. 11). When the grout material is sufficiently cured, the first excavation site B1 is excavated from the excavation section A to the planned depth, the girder beam 40-1 is installed, and the shotcrete 50 is installed (FIG. 12). Subsequently, the second excavation site B2 is excavated and similarly, the girder beam 40-2 is installed and the shotcrete 50 is installed (FIG. 13).

Excavation is performed while removing the grout hoses and air vent hoses exposed to the excavated ground ceiling part in the excavation for the ground B1 or B2 to be excavated. At this time, in order to easily remove the grout hoses and the air vent hoses which are exposed step by step in the excavation process, a notch is formed in the grout hoses and the air vent hoses to be located in the drilling holes, or the hoses are cut to a predetermined size Member may be considered.

In the case of using a steel pipe stiffener in which the auxiliary stiffener and the main stiffener are integrally formed (in the case of FIG. 17), the auxiliary stiffener is also exposed in the process of excavating the excavation ground, so it must be removed together with the grout hose and air vent hose. In the case of using the separate steel pipe stiffener (Figs. 15 and 16), since the auxiliary stiffener is removed before grouting, it is unnecessary to remove the auxiliary stiffener in the excavation process.

A part of the front end of the main stiffener 22 installed in the perforation hole H is exposed to the inside of the excavation surface and the front end of the main stiffener 22 is exposed to the outside The excavation surface is finished with a shotcrete (50) to prevent the ground from loosening and to reinforce the excavation surface will be.

14, the steel pipe reinforcing member 20 is not provided with the excavation surface side portion, and the support member 45 is provided in the lower portion in the substantially normal direction of the excavation surface, for example, a rock bolt, a tie bolt, , A steel pipe or the like to reinforce and stabilize the excavation surface (S45). The support material (45) is to withstand the ground load at the upper part of the tunnel.

According to the embodiment of the present invention, before reaching the ground to be excavated, the drilling point for installing the steel pipe reinforcement is advanced, and the steel pipe is grouted at the middle surface (drilling section) at the intermediate position. , It is possible to grooving the steel pipe for reinforcement above the tunnel excavation surface with the steel pipe installation angle (5˚ ~ 20˚) proposed in the design.

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. .

A: Excavation section B1, B2: Excavation ground
H: Perforation hole 20: Steel pipe stiffener
22: main stiffener 24: auxiliary stiffener
26: grout hose 27: clearance material
28: Airbot Hose 29: Water Billing
40: Kangji Bridge 45: Support
50: Shotcrete

Claims

A tunnel reinforcement method in which the upper part of a tunnel excavation surface to be excavated is previously reinforced with a steel pipe reinforcing material 20 and then a tunnel is excavated to a planned depth and a girder 40 and a shotcrete 50 are installed on the excavation surface, As a result,
A drilling step (S10) of forming a perforation hole (H) inclined upwards from an excavation end face (A) of the excavation soil toward the upper part to be excavated;
A grouting step (S20) of inserting the steel pipe stiffener (20) into the hole (H) and grouting the steel pipe stiffener (20) to fix the steel pipe stiffener (20) to the hole (H) and reinforcing the steel wall;
An excavating step (S30) of excavating the excavated ground from the excavated section (A) to a planned stepwise depth;
A steel girder beam installing step (S40) of installing the steel girder beam (40) on the excavation surface; And
And a step (S50) of placing a shotcrete reinforcing the excavation surface by arranging the shotcrete (50) to a thickness at which the steel girder beam (40) can be buried,
In the drilling step (S10), at least one creepage site existing between the excavation section (A) and the Nth precipitation site passes from the excavation section (A) above the precipitation site N of the Nth excavation site (N-1) through the hole (H).

The method according to claim 1,
A forward steel pipe stiffener 20-1 installed at the upper part of the excavation site and a post pipe steel stiffener 20 installed at a perforation hole H passing over the Nth steel girder site N of the excavation site, -2) are overlapped with each other so that the Nth precipitation site (N) is positioned at the overlapping start point.

The method according to claim 1,
Wherein the steel pipe stiffener (20) is inserted into the hole (H) by a direct hole drilling method in which the steel pipe stiffener (20) is pushed into the hole (H) at the same time as the drilling.

The method according to claim 1,
The steel pipe stiffener 20 is composed of a main stiffener 22 and an auxiliary stiffener 24 connected in a straight line,
The auxiliary stiffener 24 is inserted into the perforation hole H together with the main stiffener 22 and removed from the main stiffener 22 when the main stiffener 22 is inserted to a predetermined position,
Wherein only the main stiffener (22) inserted in a predetermined position of the perforation hole (H) is fixed by grouting.

5. The method of claim 4,
And one end of the main reinforcement 22 is positioned in the perforation hole H above the Nth N strong ground station N. [

5. The method of claim 4,
The main stiffener 22 and the auxiliary stiffener 24 may be connected to each other through a hole holding pipe 210 which surrounds the opposite end portions of the two stiffeners at the same time or the side end portions facing each other may be connected to each other in a screw- The auxiliary stiffener 22 and the auxiliary stiffener 24 are formed as one body so that the auxiliary stiffener 24 can be easily detached from the main stiffener 22 by forming the notch 200 in the peripheral direction at the boundary between the two stiffeners The tunnel reinforcement method comprising:

The method according to claim 6,
Wherein at least one of the notches (200) is formed in the longitudinal direction of the auxiliary stiffener (24) so that the auxiliary stiffeners (24) exposed gradually during the tunnel excavation can be sequentially cut.

5. The method of claim 4,
The main reinforcement (22) has a plurality of injection holes for discharging the grout material to the outside, and the injection holes are formed in a spiral shape around the main reinforcement (22) so that the flexural rigidity is not lowered. Reinforcement method.

The method according to claim 1,
Wherein the grouting step (S20) simultaneously grooves grout using a plurality of grout hoses (26) of different lengths and an air vent hose (28) for air discharge.

10. The method of claim 9,
The simultaneous pressurized grouting may include:
Grout hoses 26 and air vent hoses 28 extend out of the perforation holes H from the front end of the steel pipe stiffener 20 while the grout hoses 26 extending outside the perforation holes H extend through the grout pump P, And the air vent valve (280) of the air vent hose (28) is opened;
A perforation hole sealing step of sealing the inlet of the perforation hole (H);
A grout refilling step of filling a grout material between the steel pipe reinforcing member 20 and the steel pipe reinforcing member 20 through the grout hose 26 connected to the grout pump P; And
When the grout material is ejected through the air vent hose 28, the air vent valve 280 of the air vent hose 28 is closed to pressurize the grout material to be filled with uniform pressure through the perforation hole H And a grouting step (S20).

The method according to claim 1,
Wherein grouting is performed by a multi-stage pressure grouting method in which the grout hose with the shrinkable / expandable packer is moved from the tip of the perforation hole (H) to the inlet side of the perforation hole (H) stepwise in the grouting step (S20) Way.

The method according to claim 1,
After the excavation of the excavation site by the planned depth of steps, the excavation surface side portion on which the steel pipe stiffener 20 is not installed and a support material 45 selected from a rock bolt, a tie bolt, and a steel pipe in the direction normal to the excavation surface are used Further comprising the step of installing a support material (S45) for reinforcing the excavation surface.