KR101877369B1 - Structure and method of constructing turnel - Google Patents

Abstract

The present invention relates to a construction method to reinforce a tunnel, which excavates the ground by a depth of each step to construct a tunnel, and a construction structure thereof. According to the present invention, the construction method to reinforce a tunnel comprises: a ninth excavation step of excavating the ground by a predetermined depth to form a ninth excavation space; a steel rib installation step of installing one or more steel ribs supporting the inner surface of the ninth excavation space; a reinforcement pipe installation step of obliquely inserting a reinforcement pipe into the ground in an excavation direction by a length penetrating the surround ground of the first excavation space to be excavated next, wherein the reinforcement pipe includes low and high strength sections with a different bending strength in a longitudinal direction; an inner wall finishing step of depositing shotcrete on the inner wall of the ninth excavation space to integrate the steel rib and the inner surface of the first excavation space; a first excavation step of excavating the ground by a predetermined first depth to form a first excavation space; and a second excavation step of excavating the ground by a predetermined second depth to form a second excavation space. Accordingly, collapse of the ground is economically constrained during a process to reinforce the excavated space and the space to be excavated next after the ground is excavated, thereby being able to improve safety, constructability, and economic efficiency.

Description

[0001] STRUCTURE AND METHOD OF CONSTRUCTING TURNEL [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure and a method for reinforcing a tunnel excavation surface, and more particularly, to a construction method and a construction method of a tunnel which effectively suppress the collapse of the upper gravel in the process of constructing the tunnel, .

Due to the increase of traffic volume and the increase of the size of the vehicle due to the urbanization and concentration of population, construction demand of underground structures is increasing. It is very important to secure the underground structures such as tunnels when they are applied to the soil or rocky ground where the surrounding environment is weak.

In order to secure the stability of the excavation surface of the tunnel, various ground reinforcement methods have been applied. Among them, as shown in FIGS. 1 and 2B, a steel pipe grouting method in which a steel pipe is inserted into a ground around the inner wall of a tunnel to stabilize the ground Is applied.

In the steel pipe grouting method, the excavation space V excavated for the construction of the tunnel acts on the ground (55) downward from the surrounding ground (55), so that the ground (Pz) 55 is a method of inserting a steel pipe 10 slantingly around the excavation space V in an excavation direction so as to stabilize the surrounding ground of the excavation space V. [

Generally, with the excavation completed, the steel pipe 10 is designed in such a form that it is supported in two piles as shown in Fig. 2A in the surrounding arrangement of the excavation space (V). Accordingly, the earth pressure Fg is applied to the inner wall layer 30 inserted in a shotcrete or the like around the steel pipe 10 inserted in the ground 55, the grouting material 10a surrounding the periphery of the steel pipe 10, and the excavation space V Thereby being supported in a safe state.

However, during the excavation process of the tunnel, the excavation process for digging out the ground 55 and the reinforcing process for reinforcing the already excavated space and the space to be excavated are performed. During the excavation process (T0- T1 is supported by a double-layered steel pipe 10 so that the risk of collapse is low and a sufficiently high safety factor SF1 is ensured. However, during the reinforcement process (T1 to T0) The risk of collapse is high and there is a risk of construction at a low safety factor (SF2) of about 50 to 60% of the safety factor (SF1) of the design value.

More specifically, as shown in FIG. 2A, the step of excavating and constructing the tunnel by predetermined depths (..., L9, L1, L2, ...) is performed by excavating a tunnel for excavating the ninth excavation space V9 After the process is performed, the ninth excavation space that has already been excavated is reinforced with the steel girder 20, and at the same time, the steel pipe 10V1 is cut so as to cross the circumferential ground 55 of the first excavation space V1 to be excavated A reinforcing step for reinforcing the reinforcing steel plate is inserted and installed in an inclined manner in the excavation direction.

Here, the steel pipe 10V1 to be installed is formed by perforating the perforation hole in the peripheral ground 55, then inserting the steel pipe 10V1 and injecting the grouting material 10a. By such a reinforcing process, the periphery of the excavation space V is surrounded by the steel pipe 10 and the grouting material 10a, and the upper ground is collapsed downward, and the lower ground collapses downward It is possible to suppress the small collapse.

The circumferential ground 55 of the tunnel excavation space V is reinforced by the steel pipe 10 and the like while repeating the above-described method in the first and second excavation spaces V1 and V2, Construction.

2A, in a state where the first excavation space V1 is excavated, the ninth steel pipe 10V9 and the first steel pipe 10V1 installed in the reinforcing process for excavating and reinforcing the previous excavation space So that the circumferential ground 55 is doubly reinforced. Therefore, during the excavation of the first excavation space V1, the ground is reinforced by the double-layer steel pipe 10 and the grouting material 10a, so that the safety factor (SF1 in FIG. 3) The excavation process can be performed.

However, due to the placement of the first excavation space, the second excavation space V2 to be excavated next is always in a state in which the collapsing force Pz is acting downward, whereby the strong bezel 20 is installed The upper side of the second excavation space V2 is closed until a reinforcement process is performed in which a perforation hole 10V2x crossing the second excavation space V2 is drilled and a steel pipe 10 is installed in the perforation hole 10V2x Since the steel pipe 10 is supported only by one steel pipe 10, the safety factor against the risk of collapse has a much lower value (SF2 in Fig. 3) as compared with the prediction at the time of design.

However, in the state where the steel pipe 10V2 across the second excavation space V2 is installed, as shown in Fig. 2C, as it is supported by the two-ply steel pipe 10 and the grouting material 10a, The load Pz causing the load to be generated is greatly reduced. In the excavation process for excavating the second excavation space V2, the safety factor SF1 maintained at the time of designing is maintained again.

As shown in FIG. 3, the tunneling method of the conventional steel pipe grouting method is performed in a state in which a high safety factor (SF1) for ground collapse is ensured. However, The reinforcement process has a serious problem that it is carried out with a low safety factor (SF2) against the ground collapse. Further, the period (T0 to T1) required for the excavation process for excavating the depths (L9, L1, L2, ...), which are generally set in a stepwise manner, takes about 2.5 to 3.0 days. (T 1 to T 0) also takes about 2 to 2.5 days. Therefore, despite the fact that it takes a long period of time in the low safety factor (SF 2) in the construction process of the tunnel, It is not done.

On the other hand, in the process of excavating the second excavation space V2 supported by one steel pipe 10V1, there is a high possibility that the ground collapses due to the earth pressure Fg. Therefore, the cross- It is necessary to arrange the steel pipe 10 very densely in the circumferential direction of the excavation space V1 as a result of which the time required for the operation is delayed and the required amount of the steel pipe 10 is increased, have.

Generally, the distance between the steel pipes 10 is set to 300 mm to 500 mm. In order to reduce the risk of collapse occurring in the excavation process of the ground, it is possible to find a way to reduce the gap between the steel pipes more than necessary. However, The number is increased, which is disadvantageous in terms of material cost and workability.

The above-described prior art describes the background art for deriving the present invention, and does not describe a known technology before the present application date. In other words, although the structure in which the steel pipe grouting method is applied in the course of excavating a tunnel is already known, the construction in which the safety factor regarding the collapse is varied in the excavation process and the reinforcement process and the configuration in which the risk of collapse is high in the excavation space Does not mean a known technique.

Korean Registered Patent No. 10-1750273

In order to solve the above-mentioned problems, the present invention is characterized in that, in the construction while repeatedly excavating the tunnel to a predetermined depth, the supporting force of the reinforcing tube for supporting the surrounding ground during the reinforcing process after the excavation process is lowered Thereby eliminating the problem that the possibility of collapse is increased, thereby making it possible to construct a safe tunnel.

At the same time, in reinforcing the surrounding ground in the excavation space of the tunnel, the present invention reinforces the cross section modulus of the reinforcement pipe differently depending on the region where the earth pressure acts, so that a small number of reinforcement pipes are spaced apart The objective is to economically and efficiently reinforce the ground around the tunnel.

Further, the present invention is also applicable to a structure in which the end of a reinforcing pipe inserted in a peripheral ground of a digging space is fixed in a ground so that the earth pressure over which the ground is collapsed becomes excessive, So as to suppress the phenomenon that the reinforcing pipe is detached from the ground and can not support the ground, thereby realizing a higher reinforcing ability.

Incidentally, the present invention aims to improve the workability while economically reinforcing the surrounding ground during the construction of the tunnel.

In order to achieve the above object, the present invention provides a tunnel construction method for constructing a tunnel by excavating a ground to a depth of a step to construct a tunnel, the tunnel construction method comprising the steps of: 9 excavation step; A girder beam installing step of installing at least one girder beam supporting an inner surface of the ninth excavation space; The reinforcing pipe is inserted into the ground with a length passing through the perimeter ground of the first excavation space to be excavated so as to be inclined in the excavation direction, and the reinforcement pipe has a low stiffness region having different bending stiffness along the longitudinal direction Preparing a reinforcing pipe by preparing a pipe including a high rigidity region and installing the reinforcing pipe; An inner wall finishing step of installing a shotcrete on the inner wall of the ninth excavation space to integrate the inner surface of the first excavation space with the steel girder; A first excavation step of excavating the ground by a predetermined first depth to form the first excavation space; A second excavation step of excavating the ground by a predetermined second depth to form the second excavation space; Thereby providing a reinforcement construction method of the tunnel.

This is because, in the process of constructing the tunnel while repeatedly digging the ground with the step depth, the reinforcing pipe for reinforcing the perimeter of the tunnel is not formed to have a certain cross-section, and a high rigidity region having high flexural rigidity and a low flexural rigidity So that the reinforcement can be restrained from being collapsed by the reinforcement pipe in a more economical and efficient manner by supporting the reinforcement pipe in a region having different flexural rigidity according to the magnitude of the earth pressure acting from the ground It is for this reason.

The term " high stiffness area " as used in this specification and claims does not vaguely mean a flexural stiffness higher than a certain value, but is defined to have a higher flexural stiffness than a " low stiffness area ". The term " peripheral ground " as used in this specification and claims refers to the ground around the excavation surface located around the excavation space.

The term 'angle of repose (ang)' in the present specification and claims is defined as an angle (ang) between a horizontal plane and an inclined plane occurring when a soil or a rock is piled or shaved. Generally soil, sand, and gravel are about 30 degrees, but it is known that the ground excavated for tunnel construction is '45 degrees + friction angle / 2 '.

In particular, the high-rigidity region is disposed on the peripheral ground of the second excavation space, and the inclined plane assumed to reach the bottom end of the end section of the first excavation space, In the danger zone between the most deeply located steel girder beams of FIG. As a result, the high rigidity region of the reinforcing pipe is disposed within the range of the angle of elevation which is likely to collapse by itself in the peripheral ground of the second excavation space newly excavated by the high rigidity region of the reinforcing pipe, It is possible to reliably reinforce the peripheral ground of the second excavation space while minimizing the range of the high rigidity area.

At this time, it is preferable that the high stiffness region of the reinforcing pipe is formed over the whole of the dangerous region, but it may be formed in a part of the dangerous region depending on the solidity of the ground. When the high-strength region is formed in a part of the dangerous region, the high-rigidity region of the reinforcing pipe is disposed in a continuous form at the central portion of the dangerous region, thereby effectively reducing the bending deformation to the earth pressure while minimizing the amount of steel used in the reinforcing pipe . However, the present invention is not limited to this, and instead of being disposed symmetrically with respect to the central portion of the dangerous zone, the high-rigidity zone may be offset from the center of the dangerous zone, depending on the ground condition.

Meanwhile, the gap between the insertion end of the reinforcing tube and the high-rigidity region is formed in the low-rigidity region, and the economical efficiency can be secured by reducing the amount of steel used in the reinforcing pipe in a region where the earth pressure acts.

In addition, the insertion end of the reinforcing tube can be formed with a larger enlarged cross-section than the low-rigidity region. Thus, even if the insertion end of the reinforcing tube is held and fixed in the ground and the earth pressure acts on the reinforcing tube in the direction of gravity to increase the bending deformation, the insertion end of the reinforcing tube is clamped to the ground So that it is possible to prevent the reinforcing tube from falling off from the position together with the ground collapse. As the rotational displacement is suppressed at the insertion end of the reinforcing tube, the reinforcing tube against the earth pressure behaves as a clamped one end rather than the both end supporting type, and the bending resistance ability of the reinforcing tube to the same earth pressure It is possible to obtain an effect of supporting a higher earth pressure by a reinforcing pipe made of a smaller amount of steel material.

At this time, it is preferable that the enlarged end face formed at the insertion end of the reinforcing tube is disposed outside the dangerous area. However, the present invention is not limited to the structure in which the enlarged end face is formed only outside the dangerous area, Can be placed within the hazardous area. The enlarged cross section is sufficient to be disposed at the insertion end of the reinforcing tube, and is not limited to the configuration in which the insertion end is formed. Therefore, it is sufficient that a larger enlarged cross-section is formed on the insertion end portion of the reinforcing tube than the low-rigidity region to some extent outside the dangerous region.

Here, it is preferable that the distal end fixing portion formed at the insertion end portion of the reinforcing tube is formed to have a length longer than that of the lower portion in the action direction of the earth pressure. Thus, even if the insertion end portion is clamped to the ground and the upwardly bending displacement occurs, the upper side is formed to be longer than the lower side with respect to the acting direction of the earth pressure, so that the upward bending displacement is minimized This can be achieved.

In the meantime, the reinforcing pipe installing step may include: a perforation hole forming step of forming a perforation hole in the ground; A reinforcing tube inserting step of inserting the reinforcing tube into the perforation hole; A grouting step for grouting a space between the perforation hole and the reinforcing tube; And the like. In some cases, the reinforcing pipe may be installed so as to be supported by a strong steel beam installed at the deepest position of the ninth excavation section. As a result, even if axial displacement of the reinforcing pipe installed in the circumferential ground of the excavation space occurs due to earth pressure, the other end of the reinforcing pipe is prevented from being displaced in the axial direction by the steel girder, .

On the other hand, the high-rigidity region of the reinforcing tube can be configured to enhance the rigidity in various ways with respect to the low-rigidity region. The high stiffness region of the reinforcing pipe may be formed as a double pipe by an outer reinforcing pipe surrounding the periphery of the inner reinforcing pipe forming the low stiffness region so as to have higher rigidity than the low stiffness region . If the high-rigidity region is formed by the double pipe that surrounds the periphery of the inner reinforcement pipe by the outer reinforcement pipe, not only the uniform rigidity is provided for the circumferential direction but also the high rigidity region It is possible to obtain an advantage that the bending stiffness value can be more easily adjusted.

Here, the inner reinforcement pipe and the outer reinforcement pipe may be formed in close contact with each other.

Preferably, the outer reinforcing tubes are spaced apart from each other with respect to the inner reinforcing tube so that an increase in the section modulus due to the outer reinforcing tube can be further increased compared to the predetermined material use amount.

In this case, the inner reinforcing pipe and the outer reinforcing pipe may be connected to each other by a connecting member for supporting the load, and may be filled with a filler such as concrete, non-shrinkage mortar or the like. By filling the gap between the inner reinforcing pipe and the outer reinforcing pipe with the filling material, the outer reinforcing pipe and the inner reinforcing pipe are integrally supported with respect to the earth pressure, so that a higher bending resistance capability can be realized.

When the outer reinforcement pipe is disposed so as to be spaced apart from the inner reinforcement pipe, it is preferable that the end portion of the outer reinforcement pipe is formed in a tapered region that is gradually reduced in section and connected to the outer surface of the inner reinforcement pipe. As a result, the sidewalls of the low-stiffness region and the high-stiffness region are buffered in the tapered region, so that local stress concentration on the reinforcing tube can be avoided.

The inner reinforcement pipe and the outer reinforcement pipe are spaced apart from each other, and the end portion of the outer reinforcement pipe is formed in a tapered shape gradually reducing in section, and the outer reinforcement pipe has a lower side The inner reinforcement pipe and the outer reinforcement pipe may be filled with the filler material. As a result, the lower side of the outer reinforcement pipe is formed longer than the upper side, so that the amount of material used can be reduced while more effectively canceling downward earth pressure.

According to another aspect of the present invention, there is provided a hydraulic excavator comprising: a ninth excavation space formed by excavating a ninth depth; a first excavation space formed by excavating the ninth excavation space by a first depth; And a second excavation space formed by excavating the first excavation space by a second depth after excavation of the first excavation space, wherein the construction of the tunnel is constructed such that the circumference of the first excavation space A reinforcement pipe inserted in an inclined manner with respect to the excavation direction so as to pass through the ground, the reinforcing pipe including a low rigidity region and a high rigidity region having different flexural rigidities along the longitudinal direction; A rigid beam supporting the inner surface of the excavation space, wherein at least two rigid beams are installed in the ninth excavation space in the depth direction; A shotcrete finishing inner wall layer laid on an inner wall of the excavation space to integrate the girder beam with the inner surface of the excavation space; The tunnel construction structure according to claim 1,

In particular, the high-rigidity region is disposed on the peripheral ground of the second excavation space, and the inclined plane assumed to reach the bottom end of the end section of the first excavation space, The reinforcing process performed after the excavation process is provided with a higher safety factor because of its high restraining ability against collapse even when it is supported by one reinforcing pipe It is possible to obtain an effect that can be safely performed.

The insertion end of the reinforcing tube is formed to have a larger enlarged cross-section than the low-rigidity region, and the rotational displacement at the insertion end of the reinforcing tube is suppressed, so that the reinforcing tube of a predetermined cross section can withstand a larger earth pressure The effect can be obtained.

As described above, according to the present invention, in a process of constructing a tunnel while repeating excavation of the ground with a step depth, a high stiffness region and a low stiffness region are formed in the reinforcing pipe for reinforcing the perimeter ground of the tunnel, A reinforcement construction method of the tunnel and a construction structure thereof, in which the earth pressure is smoothly supported by a small material by disposing a high stiffness region in the region where the tunnel works.

Particularly, in the present invention, in the reinforcing process of inserting the reinforcement pipe at an inclined position on the perimeter ground in the already excavated excavation space and injecting the grouting material, the ground located on the upper side of the excavation space to be excavated next, Even if it is supported by a small number (for example, one) of reinforcement pipes in comparison with a predetermined number (for example, two), the earth pressure acting on the surrounding ground of the excavation space to be excavated next It is possible to obtain an advantageous effect of securing safety during the reinforcement process during the tunnel construction process by greatly reducing the probability of collapse of the ground by being supported by the rigid region.

First of all, according to the present invention, an area between a deepest placed strong ground beam of a first excavation space already excavated and a virtual inclined surface constituting a rebound angle is regarded as a dangerous area, It is possible to reduce the risk of collapse while minimizing the amount of steel material by reinforcing the region of action of the earth pressure affecting the ground collapse to the region of high rigidity of the reinforcing pipe .

According to the present invention, a high stiffness region of the reinforcing pipe can be arranged over the entire section of the dangerous region. However, the high stiffness region of the reinforcing pipe may be disposed in a part of the dangerous region, The effect of lowering the risk can also be obtained.

That is, according to the present invention, the reinforcing pipe used for reinforcing the surrounding ground of the tunnel is divided into a high rigidity region and a low rigidity region, and a high rigidity region is disposed as a double pipe, and both ends of the outer reinforcing pipe are tapered Thus, concentration of local stress on the reinforcing tube is prevented, thereby achieving an effect of realizing a higher reinforcing ability.

According to the present invention, a high rigidity region of the reinforcing pipe is disposed as a double pipe, and the reinforcing pipe is filled with filler such as non-shrinkage mortar between the inside reinforcing pipe and the outside reinforcing pipe, As the pipe moves in unison, it can support the earth pressure and obtain higher resistance ability.

Thus, the present invention can reduce the risk of collapse that may occur during the reinforcing process performed after the tunnel excavation process, even if the number of the reinforcing pipes to be installed is not increased in the construction while repeatedly drilling the tunnel to a predetermined depth It is possible to achieve an advantageous effect that economical safety construction can be realized.

FIG. 1A is a cross-sectional view showing a tunnel reinforcing structure of a conventional steel pipe reinforcing system,
FIG. 1B is a sectional view taken along the line AA in FIG. 1A,
Figs. 2A to 2C are partially enlarged views of Fig. 1B, and are views for explaining a stepwise excavation process and a reinforcement process,
FIG. 3 is a graph showing the safety factor during the stepwise excavation process and the reinforcing process of FIGS. 2A to 2C,
FIG. 4 is a flowchart showing a tunnel reinforcement construction method according to an embodiment of the present invention,
FIGS. 5A through 5C are views showing a configuration according to a tunnel reinforcement procedure according to an embodiment of the present invention; FIGS.
FIG. 6 is an enlarged view of a portion 'B' in FIG. 5B,
FIG. 7A is a view showing a distribution of earth pressure acting on the reinforcing tube of FIG. 6,
FIG. 7B is a graph showing the safety factor during the stepwise excavation process and the reinforcing process of FIGS. 5A to 5C,
8A is an enlarged view of another embodiment corresponding to the portion 'B' in FIG. 6,
FIG. 8B is a view showing a distribution of earth pressure acting on the reinforcing pipe of FIG. 8A,
Fig. 9 is an enlarged longitudinal sectional view of the reinforcing tube of Fig. 5B,
10A to 10C are longitudinal sectional views showing the structure of a reinforcing tube as an example applicable to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the subject matter of the present invention.

As shown in the drawing, the reinforcement structure 100 of a tunnel according to an embodiment of the present invention excavates the ground 55 by a predetermined depth (..., L9, L1, L2, ...) (110X, 110Y, 110Z, 110V8, 110V9, 110V1; 110) installed to be inclined from the excavation surface in the excavation direction to stabilize the ground on which the earth pressure Fg acts with respect to the excavation space (V) A steel girder 120 supporting an inner surface of the excavation space V and an inner wall layer 130 injecting shotcrete into the inner surface of the excavation space V to integrate the steel girder 20 and the excavation surface .

The excavation space V is formed by drilling stepwise by a predetermined depth (..., L9, L1, L2, ...), but the depth to be excavated each time is variable depending on the ground state or the work state It is possible.

The girder beam 20 is installed along the excavation direction in such a manner as to contact the cross section of the excavation space to support the excavation surface as shown in FIG. The steel beam 20 is generally formed of a steel beam of an H-shaped section, but may be formed of various types of sections and materials.

The inner wall layer 130 may be formed by integrating the excavation surface formed by the excavation process and the girder 120, and may be formed by injecting shotcrete. However, the present invention is not limited to the structure in which the inner wall layer 130 is formed by shotcrete spraying, and includes an inner wall layer formed by various finishing methods for integrating the excavation surface and the girder 120.

The reinforcement pipe 110 is inserted from the excavation surface of the already excavated excavation space and then sloped and inserted into the ground with a length passing through the circumferential ground 55 of the excavation length L2 to be excavated next, (55) is reinforced to stabilize the ground (55).

The reinforcement pipe 110 according to the present invention may be formed into various cross-sectional shapes such as a rectangular cross section, a hexagonal cross section, and a circular cross section, but it is preferable that the reinforcement pipe 110 has a circular shape having a higher flexural rigidity It is preferable that it is formed as a pipe of a cross section. The material of the reinforcing pipe 110 may be formed of various metallic materials such as steel having high impact resistance and high ductility while having high flexural rigidity.

The reinforcing pipe 110 may be installed in a variety of ways such as one to three columns for each excavation space V9, V1, .... Hereinafter, for convenience, a structure in which one row of reinforcing tubes 110 are inserted into one excavation space as illustrated in FIGS. 6 and 7 will be described as an example.

When the excavation space V is formed, the reinforcing pipes 110V1, 110 are inserted into the ground 55 in an inclined manner from the excavation space V toward the excavation direction, And a reinforcing pipe 110 is inserted into the perforation hole 110x and a grouting material 112 such as no shrinkage mortar is filled in the space inside the perforation hole 110x to reinforce the ground 55 The reinforcing pipe 110 and the grouting material 112 reinforce the ground on the upper side and the ground on the lower side thereof while integrating the pipe 110 together.

According to an embodiment of the present invention, the other end of the reinforcement pipe 110 may be disposed to be supported by the steel girder 120. Thus, the axial displacement of the reinforcement pipe 110 can be transmitted to the reinforcement pipe 110, (120) to further enhance the ability to support the earth pressure (Fg) by the reinforcing tube (110). However, the present invention is not limited to the case where the other end of the reinforcement pipe 110 is not supported by the steel girder 120, but may be disposed only in the state of being embedded in the circumferential ground 55.

However, the reinforcing pipe 110 according to the present invention has a low rigidity region 110a having a relatively low flexural rigidity and a low rigidity region 110b having a relatively low flexural rigidity. However, the conventional reinforcing pipe 10 has a substantially uniform cross- A high rigidity region 110b formed in a continuous shape with a high rigidity as compared with the rigid portion 110a and a leading end fixing portion 110e formed into a larger enlarged end face to be inserted into the ground. Although the leading end fixing portion 110e has been described up to the end of the reinforcing tube 10 in the drawing, it is sufficient that the leading end fixing portion 110e is partially disposed in a dangerous area Ac described later.

The low rigidity region 110a of the reinforcing tube 110 can be disposed in a region where the load due to the earth pressure does not largely act. For example, when the high stiffness region 110b is disposed only in a region between the high stiffness region 110b and the insertion end portion 110e or only a part of the center of a dangerous region Ac described later, (The end near the excavation surface) and the high-rigidity area 110b. That is, the region where the low-stiffness region 110a is disposed can be arranged in a region having a high rigidity and a region where the leading end fixing portion 110e of the expanded end face is not formed according to the ground conditions.

The high stiffness region 110b of the reinforcing pipe 110 is disposed in a continuous form on the perimeter ground of the excavation space that has not yet been excavated. Here, the high-rigidity region 110b has a cross-section in a range of 1.5 to 15 times flexural rigidity as compared with the low-rigidity region 110a. Accordingly, the high earth pressure is supported by the high-rigidity region 110b of the reinforcing pipe 110 during the process of reinforcing the excavation space, so that even in a region where the entirety is formed to have a uniform cross- It is possible to improve the workability and economical efficiency of the prior art in which the reinforcing tube 110 is arranged densely.

Before the first excavation space V1 is excavated, the perimeter ground 55 of the first excavation space V1 is divided by the ninth reinforcing pipe 110V9 and the first reinforcing pipe 110V1 into 2 The girth of the first excavation space V1 is reinforced by the reinforcing pipes 110V1 and 110V9 at a sufficiently high safety factor (SF1 in Fig. 7B). Therefore, the excavation process of the first excavation space V1 is performed in a state sufficiently reinforced to prevent the ground collapse.

When the excavation process is performed for the first excavation space V1 and a plurality of the strong girder beams 120 are disposed along the depth direction with respect to the first excavation space V1 to support the excavation surface, The section that is supported by the tether is in a safe state without the risk of collapse. However, the danger zone Ac of the space between the outermost (the deepest in the excavation direction) and the virtual envelope 88 forming the angle of angles from the lower end of the first excavation space V1, Of the ground 55 becomes a load condition that can be easily collapsed. In other words, the perimeter ground 55 of the dangerous area Ac is supported only by the first reinforcement pipe 110V1, similarly to the conventional structure of Figs. 2A to 2C. In this case, the angles at the ground where the tunnel is constructed vary depending on the soil and rock constituting the ground 55, and are generally set to 45 degrees + φ / 2 (where φ is the friction angle of the ground).

According to the present invention, since the high stiffness region 110b of the first reinforcing pipe 110 supports the ground of the dangerous region Ac with higher flexural rigidity, after the strong stake 120 is installed A second reinforcing pipe 110V2 is inserted into the second perforation hole 110V2x and a grouting material 112 is injected into the second perforation hole 110V2x (FIG. 5B), which takes about 2 to 2.5 days to fill the inner wall layer 130 with the shotcrete poured into the excavation surface of the first excavation space V1, is performed in a much safer environment The effect can be obtained.

In other words, according to the present invention, the interval between the outermost strong bead and the inclined virtual envelope 88 is defined as the dangerous area Ac, and the earth pressure acting on the hazardous area Ac is set to the height of the reinforcing pipe 110 By the support by the rigid region 110b, it is possible to obtain an effect of efficiently supporting the earth pressure Fg that acts during the excavation process. At this time, the high-stiffness region 110b may be formed over the whole of the hazardous area Ac, but may be formed only in a part of the hazardous area Ac depending on the possibility of collapse of the girth 55 of the excavation space . When the high stiffness area 110b is formed in a part of the dangerous area Ac, the high stiffness areas 110b may be provided in a discontinuous manner at a central part of the hazardous area Ac However, in order to obtain a high bending resistance at a higher earth pressure Fg while forming the high-rigidity area 110b with a small length, it is preferable that the high-rigidity area 110b is disposed in a continuous form at the center part of the dangerous area Ac Do.

According to another embodiment of the present invention, the high-stiffness region 110b may be offset from the central portion of the hazardous region Ac depending on the state of the ground, and although not shown in the drawings, 110b may extend to the outside of the hazardous area Ac. For example, in a case where it is necessary to reinforce reinforcement on the side where the other end of the reinforcing pipe having a high possibility of collapse is located (in the direction of excavation) depending on the ground condition such as the ground more rigid in the excavation direction, May be disposed so as to be offset toward the other end in the dangerous area Ac. As described above, the high stiffness region can be disposed in the central portion of the hazardous area Ac or offset from the central portion in accordance with the ground conditions, thereby securing safety during the reinforcing process performed after the excavation process.

Depending on the length of the reinforcing pipe 110 used in the construction of the tunnel and the installation position in each excavation space V, the reinforcing pipe 110 already installed in a part of the dangerous area Ac is divided into two layers (The number of pipes scheduled to be designed at the time of design, that is, the number of reinforcing pipes supporting the excavation space in the completed state). 6, there is an extended section Ad formed by extending the ninth reinforcing pipe 110V9 in the dangerous area Ac. In this case, the concentrated load area excluding the extended section Ad from the dangerous area Ac, The high stiffness region 110b of the first reinforcing pipe 110V1 may be disposed in the high-strength region Ac-Ad. Although there is no need to reinforce the region in which the low stiffness region 110a of the ninth reinforcing pipe 110V9 and the first reinforcing pipe 110V1 are overlapped in two layers as described above, The high stiffness region 110b of the first reinforcing pipe 110V1 is located outside the point where it meets the extension line 77 extending from the end of the ninth reinforcing pipe 110V9 in the direction of action of the earth pressure Fg Excavation direction).

However, it is important to reliably prevent the collapse in the dangerous area (Ac). Therefore, even if the area supported by the double-layer reinforced tube is a part of the dangerous area (Ac) It is more preferable that the high rigidity region 110b of the tube 110 is disposed.

6 shows a structure in which the starting position of the high stiffness region 110b coincides with the end of the reinforcing pipe 110V9 previously installed. However, the present invention is not limited to this, and the reinforcing pipe 110V9, Only a part of the high-rigidity area 110V9 may be formed from a deeper position in the excavation direction.

As described above, by arranging the reinforcing pipe 110 so as to support the ground of the high-stiffness region Ac and the high-stiffness region 110b of the reinforcing pipe 110, The reinforcing process of the excavation region V can be performed in a high safety factor (SF3) state of about 80 to 90% close to the safety factor SF1 of the design value, thereby making it possible to achieve safe construction.

Incidentally, since the magnitude of the earth pressure Fg that can be supported by one reinforcing pipe 110 is increased, the distance d in which the reinforcing pipe 110 is disposed in the circumferential direction of the excavation space V is set to be It is possible to distribute the size more greatly than the size of 300 mm to 500 mm. The present invention is characterized in that a high rigidity region 110b having a higher bending stiffness than a part of the dangerous area Ac or the concentrated load area Ac-Ad, It is possible to realize a high reinforcing effect with a minimum amount of material, and an excellent effect of simultaneously obtaining safety, economical efficiency, and workability in a tunnel construction process is obtained.

The effect is also applied to the case where the ground is hard and the end of the reinforcing pipe 110 is supported on the surface of the rigid body (Figs. 7A and 8B). However, when the ground is weak and the end of the reinforcing pipe 110 It is obvious that the same is obtained even when the spring is supported by the spring.

5A to 6, the insertion end portion of the reinforcing tube 110 can form a leading end fixing portion 110e having a larger enlarged cross-section. As shown in the drawing, the tip end fixing portion 110e formed by the enlarged end face may be extended to the end of the reinforcing tube 110. Although not shown in the drawing, the tip end fixing portion 110e may be formed before the end of the reinforcing tube 110 As shown in FIG. In general, it is advantageous that the leading end fixing portion 110e is disposed outside the hazardous area Ac, but in some cases, a part of the leading end fixing portion 110e may be extended to the inside of the hazardous area Ac.

As a result, the insertion end of the reinforcing pipe 110 is integrated with the filling material 112 filled in the perforation hole 110x with a higher rigidity, so that the insertion end of the reinforcing pipe 110 is downwardly moved by the earth pressure Fg acting on the reinforcing pipe 110 Even if a large bending deformation occurs, the insertion end of the reinforcing tube 110 may be fixed to the ground like an anchor, while being cantilevered, although it may vary depending on the rigidity of the surrounding ground 55 Even if the amount of bending deformation of the reinforcing tube 110 is increased, the reinforcing tube 110 maintains the position in the clamped state without releasing from the perforation hole 110x, so that a higher bending resistance capability can be obtained.

At the same time, since the rotational displacement is suppressed by the tip end fixing portion 110e of the enlarged end face at the insertion end of the reinforcing pipe 110, the reinforcing pipe 110 is positioned at the earth pressure Fg The one end (91) behaves to have a convex bending deformation upward and to be able to withstand a higher earth pressure. In this case, the length of the tip end fixing portion 110e can be set to 50 to 500 mm, and the diameter of the end surface fixing portion 110e can be set to 1.5 to 15 times the outside diameter of the low-stiffness region.

According to another embodiment of the present invention shown in FIG. 8A, the present invention is not limited to the configuration in which the insertion end portion of the reinforcing tube 110 is formed into a larger-diameter end rigid portion 110e. Rigid region 110b from the boundary with the rigid region 110b to the end of the tube so that the tip fixing portion is not formed. In this case, as shown in FIG. 8B, in the state where the earth pressure Fg acts on the reinforcing tube 110 and the downward deflection displacement occurs, the one end of the reinforcing tube 210 is rotated as shown in FIG. The resistance against the earth pressure is reduced, but it can be applied to the case where the tunnel is excavated with respect to the ground where the need of the ground reinforcement is low.

The high stiffness region 110b and the low stiffness region 110a of the reinforcing tube 110 may be formed in various shapes. For example, the high rigidity region 110b may be formed of a solid tube, and the low stiffness region 110a may be formed of a hollow tube. In the high-rigidity region 110b, the reinforcing bars may be formed in the shape of wrapping the outer periphery of the reinforcing bars along the longitudinal direction or spirally so as to reinforce the flexural rigidity, and the low-rigidity region 110a may be formed only of the pipe without reinforcing bars. As described above, the high rigidity region 110b can be configured to have a higher rigidity than the low rigidity region 110a in such a manner that additional members are attached or filled. In addition, the high-stiffness region 110b may be formed such that the cross-section in the region is uniformly formed as a whole, but the cross-section within the region is varied. That is, it is sufficient if the high-rigidity region 110b is formed to have a section having higher rigidity than the low-stiffness region 110a.

According to one embodiment of the present invention, in order to obtain a larger section modulus with a given amount of material and to prevent twisting deformation in the earth pressure in various directions, as shown in Figs. 9 to 10C, So that a high rigidity region and a low rigidity region can be formed, respectively.

9, the reinforcement pipe 110 is formed such that the outer reinforcement pipe 215 forming the high-rigidity region 110b is formed in a much larger cross-section than the inner reinforcement pipe 113, And the inner surface of the tube 215 is disposed apart from the outer surface of the inner reinforcing tube 113. As a result, the section modulus can be greatly increased as compared with the amount of steel used in the outer reinforcement pipe 215, so that resistance to earth pressure in the high-rigidity region 110b can be improved.

Here, the outer reinforcement pipe 115 is formed so that the lower side of the action direction of the earth pressure Fg is longer than the upper side, and is filled with the filler between the inner reinforcement pipe and the outer reinforcement pipe. As a result, the lower side of the outer reinforcement pipe is formed longer than the upper side, so that the amount of material used can be reduced while more effectively canceling downward earth pressure. The tapered region 115t is formed due to the deviation of the upper side length and the lower side length of the outer reinforcement pipe 115. The inclination y / x of the taper is preferably 0.25 or less. Accordingly, when the reinforcement pipe 110 is bent downward by the earth pressure Fg to generate a convex bending deformation d110, stress is concentrated in the boundary region between the outer reinforcement pipe 115 and the inner reinforcement pipe 113 Can be prevented.

The insertion end of the reinforcing tube 110 is formed to have an enlarged cross-section that is 1.5 to 15 times greater in cross section than the inner reinforcing tube 113 so that the insertion end is clamped and fixed in the perforation hole 110x Thereby forming the tip end fixing portion 110e. Accordingly, since the insertion end of the reinforcing pipe 110 functions as an anchor fixed to the peripheral ground 55, the flexural deformation due to the earth pressure Fg becomes slightly convex upward as indicated by d110e, The fixing portion 110e is formed to have a length longer than the lower side in the direction of action of the earth pressure Fg so that the upward displacement of the insertion end portion can be minimized in comparison with the amount of material used.

Although not shown in the drawing, the end fixing part 110e may not be provided at one end of the reinforcing pipe 110 depending on the nature of the applied ground.

10A, the reinforcing pipe 110X is formed by a predetermined length of the inner reinforcing pipe 113, and the reinforcing pipe 110X is formed on the high-rigidity region 110b determined according to the ground condition around the tunnel to be installed And the outer reinforcement pipe 115 may be fixed in an adhered state surrounding the inner reinforcement pipe 113. For example, the outer diameter of the inner reinforcing pipe 113 and the inner diameter of the outer reinforcing pipe 115 are formed to be the same within a permissible tolerance range, and the edge of the outer reinforcing pipe 115 is connected to the inner reinforcing pipe 113 ) By welding or the like.

Although the outer reinforcing pipe 115 is shown as being slightly different in thickness from the inner reinforcing pipe 113, the thickness of the outer reinforcing pipe 115 may be larger. This makes it possible to easily manufacture the reinforcing pipe 110X and to make the high rigidity region 110b composed of the inner reinforcing pipe 113 and the outer reinforcing pipe 115 work together with the resistance to the earth pressure The effect can be obtained.

The reinforcing pipe 110X is formed at one end of the reinforcing pipe 110X so as to have a sufficiently large cross section than the outer reinforcing pipe 115 so that the reinforcing pipe 110X can penetrate the filler 112 to suppress the rotational displacement of the tip end fixing portion 110e. In the case shown in FIG. 8A, the tip end fixing portion may not be formed in the reinforcing tube 110X.

10B, the reinforcement pipe 110Y is formed such that the outer reinforcement pipe 215 forming the high-rigidity region 110b is formed in a much larger cross-section than the inner reinforcement pipe 113, The inner surface of the tube 215 may be spaced apart from the outer surface of the inner reinforcing tube 113. As a result, the section modulus can be greatly increased as compared with the amount of steel used in the outer reinforcement pipe 215, so that resistance to earth pressure in the high-rigidity region 110b can be improved.

On the other hand, when the inner surface of the outer reinforcing pipe 215 is spaced apart from the outer surface of the inner reinforcing pipe 113, the end of the outer reinforcing pipe 215 gradually becomes smaller in cross section and connected to the outer surface of the inner reinforcing pipe 113 It is preferable that the tapered region 215t is formed. The stress difference at the boundary of the low rigidity region 110a made only of the inner reinforcement pipe 113 and the high rigidity region 110b formed by the inner reinforcement pipe 113 and the outer reinforcement pipe 215 is tapered It is possible to prevent concentration of stress locally in the reinforcing pipe 110a supporting the earth pressure while buffering the area 215t.

Since the outer reinforcement pipe 215 and the inner reinforcement pipe 113 are connected to each other by the tapered region 215t, the outer reinforcement pipe 215 and the inner reinforcement pipe 113 in the high- Fg).

Similarly, although the tip end fixing portion 110e is formed at one end of the reinforcing tube 110Y, the tip end fixing portion may not be formed in the reinforcing tube 110X when applied in the form shown in Fig. 8A .

8A and 10C, the reinforcing pipe 110Z is formed such that the outer reinforcing pipe 315 forming the high-rigidity region 110b has a much larger cross-section than the inner reinforcing pipe 113 The inner surface of the outer reinforcing pipe 315 is spaced apart from the outer surface of the inner reinforcing pipe 113 and the filling material 317 such as non-shrinkage mortar can be filled in the space therebetween. As a result, not only the sectional modulus can be increased more than the steel material used in the outer reinforcing pipe 215, but also the compressive strength and the higher flexural rigidity due to the low-cost filler 317, A favorable effect can be obtained.

Similarly, although the tip end fixing portion 110e is formed at one end of the reinforcing tube 110Y, the tip end fixing portion may not be formed in the reinforcing tube 110X when applied in the form shown in Fig. 8 .

A filler 317 such as concrete or non-shrinkage mortar is filled between the outer reinforcing pipe 215 and the inner reinforcing pipe 113 of the reinforcing pipe 110Y shown in FIG. 10 so that the filler 317 Reinforced region 110b of the reinforcing pipe 110Y is reinforced by the high compressive strength of the outer reinforcing pipe 215 and the inner reinforcing pipe 113 to ensure the integral behavior of the outer reinforcing pipe 215 and the inner reinforcing pipe 113 .

Hereinafter, a method of constructing the reinforcement construction 100 of the tunnel according to the present invention will be described in detail with reference to the accompanying drawings.

Step 1 : First, as shown in FIG. 5A, a first excavation space V1 is formed by excavation for a predetermined first depth L1 (S110).

Here, the ninth reinforcing pipe 110V9 is installed from the eighth excavation space (not shown) before the ninth excavation space V9 is excavated, and the ninth excavation is performed before the first excavation space V1 is excavated, The first reinforcement pipe 110V1 is installed from the space V9 and the peripheral ground 55 of the first excavation space V1 is rigidly reinforced by the double reinforcing pipes 110V9 and 110V1 , The excavation process for excavating the first excavation space V1 is performed in a safe state.

Step 2 : Then, in order to reinforce the excavation surface of the first excavation space V1, the circumferential direction of the excavation surface is reinforced by the steel girder 120 having the cross-section H or other cross-sectional shape (S120). At this time, the distance in the excavation direction of the strong bezel 120 can be variously determined according to the ground, and can be set at intervals of about 0.5 m to 1.5 m.

The steel girder 120 is installed from the end face V1e of the first excavation space V1 to a position spaced apart from the end face V1e of the first excavation space V1 because a space for perforating the perforation hole 110V2x for installing the reinforcement pipe 110 is required. do. Therefore, a force Pz 'for collapse of the peripheral ground 55 acts on the vicinity of the end surface V1e of the first excavation space.

Since the peripheral ground 55 of the second excavation space V2 excavated next in the end face of the first excavation space V1 is supported only by the first reinforcement pipe 110V1, A force Pz 'in which the ground is collapsed acts on the inner area of the imaginary envelope 88 (the area on the opposite side of the excavation direction, the danger area Ac) which is inclined by the angle of repose angles from the lower end of the end face V1e of the slope V1 . The area outside the imaginary envelope 88 inclined by the angle of elevation ang from the lower end of the end face V1e of the first excavation space V1 is determined by the force Po are not in operation.

Therefore, the high stiffness region 110b is disposed in at least a part of the dangerous area Ac to reinforce the collapsing force in the dangerous area Ac. In this way, the reinforcing pipe 110 is formed to have a length penetrating the perimeter ground of the excavation space to be excavated next, and then the high rigid region 110b, it is possible to effectively cancel the earth pressure Fg acting from the ground.

6, the deflection displacement d110 in which the reinforcement pipe 110 sags downward due to the load due to the earth pressure Fg is minimized while minimizing the amount of steel material used in the high-rigidity region 110b 9, the cross-section of the outer reinforcing pipe 115 of the high-rigidity region 110b is formed to be larger than the cross-section of the inner reinforcing pipe 113 that forms the low-rigidity region 110a , Fillers such as non-shrinkage mortar can be filled therebetween. Further, the lower end of the outer reinforcing pipe 115 is formed longer than the upper end of the outer reinforcing pipe 115 with respect to the acting direction of the earth pressure, and the inclination of the tapered region 115t is kept as low as 0.25 or less, The amount of downward bending deformation d110 can be reduced.

The reinforcing pipe 110 is inserted into the reinforcing pipe 110 with a larger enlarged cross-section than the inner reinforcing pipe 113 or with a metal pipe having an enlarged cross-section, 55, the reinforcing pipe 110 is fixed in place, and the rotational displacement at one end is restrained, so that even when the ground is collapsed, Can be implemented.

However, the present invention is not limited thereto, and the configurations shown in Figs. 9 to 10C and combinations thereof can be variously applied.

Step 3 : Since the risk of collapse of the peripheral ground 55 in the dangerous area Ac of the second excavation space V2 is lowered by the high rigidity area 110b of the first reinforcing pipe 110V1, The second drilling hole 110V2x is drilled in the first drilling space V1 and the second reinforcement pipe 110V2 is inserted into the second drilling hole 110V2x and then the grouting material 112 The second reinforcing pipe 110V2 is installed in the second perforation hole 110V2x to form the inner wall layer 130 by spraying the shotcrete on the excavation surface of the first excavation space V1 140).

As described above, even if the reinforcing process in the first excavation space V1 is supported only by the first reinforcing pipe 110V1 supporting the earth pressure Fg of the ground in one layer, the height of the first reinforcing pipe 110V1 The stiffness region 110b is continuously arranged at the center portion of the dangerous area Ac and the leading end fixing portion 110e is formed at the insertion end portion so that the safety margin SF1 of 80 to 90% It is possible to obtain an effect that the reinforcing process can be performed while maintaining a high safety factor SF3.

Step 4 : The excavation process and the reinforcement process for the second excavation space V2, which is then excavated by the second depth L2, is repeated safely and repeatedly, as shown in Fig. 5C, .

After the second excavation space V2 is excavated and reinforced, steps 1 to 3 are performed again for the third excavation space V3. Thus, the construction of the tunnel is completed while repeating the process of excavating and reinforcing the excavation space step by step.

As described above, according to the present invention, even if the reinforcing process, which is essentially involved during the excavation process, is performed in a state where the reinforcing ability scheduled at the time of designing is not expressed in the process of constructing the tunnel while repeatedly excavating the ground with the depth of step, By placing the high stiffness region of the reinforcement pipe in the dangerous area (Ac) between the outermost girder beam and the imaginary envelope (88) according to the angle of repose, effectively reducing the earth pressure by the minimum amount of steel material, It is possible to obtain an advantageous effect of securely securing the safety of the ground reinforcement process which occupies a large portion of the area of the ground reinforcement.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

That is, although the embodiment shown in the drawings illustrates a structure in which the reinforcing pipe is arranged in one row for each excavation area excavated in each step, two or more reinforcing pipes may be disposed for each excavation area.

100: Construction structure of tunnel
110, 110X, 110Y, 110Z: reinforcement pipe
110V9: Ninth reinforcement pipe 110V1: First reinforcement pipe
110V2: second reinforcement pipe 110a: low rigidity region
110b: high stiffness region 110e:
112: Filler 113: Inner reinforcement pipe
115, 215, 315: outer reinforcement pipe 115t: tapered area
120: steel girder beam 130: inner wall layer

Claims (22)

A tunnel construction method for constructing a tunnel by excavating a ground at a depth of step to construct the tunnel,
A ninth excavation step of excavating the ground by a predetermined depth to form a ninth excavation space;
A girder beam installing step of installing at least one girder beam supporting an inner surface of the ninth excavation space;
The reinforcing pipe is inserted into the ground with a length passing through the perimeter ground of the first excavation space to be excavated so as to be inclined in the excavation direction, and the reinforcement pipe has a low stiffness region having different bending stiffness along the longitudinal direction Preparing a reinforcing pipe by preparing a pipe including a high rigidity region and installing the reinforcing pipe;
An inner wall finishing step of installing a shotcrete on the inner wall of the ninth excavation space to integrate the inner surface of the first excavation space with the steel girder;
A first excavation step of excavating the ground by a predetermined first depth to form the first excavation space;
A second excavation step of excavating the ground by a predetermined second depth after the first excavation step to form a second excavation space;
Wherein the reinforcing pipe is disposed in the reinforcing pipe at a position where the high rigidity region of the reinforcement pipe is disposed in the peripheral ground of the second excavation space, And the reinforcement pipe is disposed so as to be disposed in a dangerous area between an inclined surface assumed to reach the first excavation space and a deepest girder beam located in the first excavation space.
The method according to claim 1,
Wherein the high stiffness region is disposed in a continuous form at a central portion of the dangerous region.
The method according to claim 1,
Wherein the high-stiffness region is disposed at a position offset from the center portion in the dangerous region.
3. The method of claim 2,
Wherein a gap between the insertion end of the reinforcing tube and the high rigidity region is formed in the low stiffness region.
The method according to claim 1,
Wherein the reinforcing pipe has an insertion end portion formed with a larger enlarged end face than the end face of the low stiffness region.
6. The method of claim 5,
Wherein the enlarged end face of the insertion end of the reinforcing tube is formed to have a length longer than an upper side in the direction of action of the earth pressure.
7. The method according to any one of claims 1 to 6,
Wherein the reinforcement pipe has a section in the high-rigidity area larger than an end surface in the low-rigidity area.
8. The method of claim 7,
Wherein the high stiffness region of the reinforcing pipe is formed as a double pipe by an outer reinforcing pipe surrounding the periphery of the inner reinforcing pipe forming the low stiffness region.
9. The method of claim 8,
Wherein the inner reinforcement pipe and the outer reinforcement pipe are closely contacted with each other.
9. The method of claim 8,
Wherein the inner reinforcement pipe and the outer reinforcement pipe are spaced apart from each other, and the end portion of the outer reinforcement pipe is formed in a tapered shape with a gradually smaller cross section.
11. The method of claim 10,
Wherein the outer reinforcement pipe is formed to have a length longer than the upper side in the direction of the earth pressure and is filled with a filler between the inner reinforcement pipe and the outer reinforcement pipe.
9. The method of claim 8,
Wherein the inner reinforcement pipe and the outer reinforcement pipe are spaced apart from each other and a gap between the inner reinforcement pipe and the outer reinforcement pipe is filled with a filling material.
A ninth excavation space formed by excavation to the ninth depth and a first excavation space formed by excavating the first excavation space by a first depth after the ninth excavation space is excavated, And a second excavation space formed by excavating the excavation space, wherein the excavation space is excavated step by step,
A low rigidity region and a high rigidity region which are inclined with respect to the excavation direction so as to pass through the peripheral ground of the first excavation space from the ninth excavation space and have different flexural rigidity along the longitudinal direction, A risk zone between a slope assumed to reach the lower end of the end section of the first excavation space and a deepest deployed girder beam in the first excavation space is disposed on the perimeter ground of the excavation space, A reinforcing tube in which the high rigidity region is disposed;
A rigid beam supporting the inner surface of the excavation space, wherein at least two rigid beams are installed in the ninth excavation space in the depth direction;
A shotcrete finishing surface which is laid on the inner wall of the excavation space to integrate the girder beam and the inner surface of the excavation space;
Wherein the tunnel construction structure comprises a tunnel structure.
14. The method of claim 13,
And the high stiffness region is disposed in a part of the dangerous area.
14. The method of claim 13,
Wherein an insertion end portion of the reinforcing tube is formed with a part of a larger enlarged cross-section than the low-rigidity region outside the danger zone.
16. The method of claim 15,
Wherein the enlarged end face of the insertion end of the reinforcing tube is formed to have a length longer than an upper side in the direction of action of the earth pressure.
17. The method according to any one of claims 13 to 16,
Wherein the high stiffness region of the reinforcing pipe is formed as a double pipe by an outer reinforcing pipe surrounding the periphery of the inner reinforcing pipe forming the low stiffness region.
18. The method of claim 17,
Wherein the inner reinforcement pipe and the outer reinforcement pipe are spaced apart from each other and the end portion of the outer reinforcement pipe is gradually tapered to be connected to the inner reinforcement pipe in a tapered shape.
19. The method of claim 18,
Wherein the outer reinforcement pipe is formed to have a length longer than the upper side in the direction of the earth pressure and is filled with a filler between the inner reinforcement pipe and the outer reinforcement pipe.
18. The method of claim 17,
Wherein the inner reinforcement pipe and the outer reinforcement pipe are spaced apart from each other, and a gap between the inner reinforcement pipe and the outer reinforcement pipe is filled with the filler.

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