JPH03180697A - Truss type timbering and tunnel excavation method employing truss timbering - Google Patents

Abstract

PURPOSE:To perform reliable and easy execution of a work by arranging a plurality of beam main materials, curved in the same shape as an excavating sectional shape, in juxtaposition at intervals of a proper distance, integrally forming the beam main materials in the shape of a truss by means of a helical lattice material, and effecting concrete lining the beam main material serving as a reinforcing bar material. CONSTITUTION:Two or more beam main materials 1 curved along an excavating sectional shape are arranged in juxtaposition with a distance therebetween, and the beams 1 are intercoupled in the shape of a truss by means of a helical lattice material 2 to build a timbering A0. The timbering A0 is divided into a plural pieces A1, A2..., which are capable of being intercoupled by means of end plates 4. The timbering A0 is located in a tunnel and is coupled to an existing part by means of tie rods 6 for securing. The timbering A0 is deformed and located in an oblique shape, a twist shape, or a helical shape, where necessary. Further, concrete may be placed by using the beam main materials serving as a reinforcing bar material. This method performs execution of a work having load capacity and rigidity and excellent following-up properties.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a truss type shoring and a tunnel excavation method using the truss type shoring.

``Conventional technology'' Conventional shoring uses ordinary shaped steel (H-shaped steel, ■-shaped steel, U-shaped steel, etc.) and is constructed by curving these shaped steels along the cross-sectional shape of tunnel excavation. It is prepared by dividing it into multiple pieces and assembling it inside the tunnel that is being excavated to support loads such as earth pressure until the lining is completed.

The face of a tunnel is often formed vertically or perpendicular to the direction of excavation, with the exception of special exceptions such as inclined shafts.Therefore, the direction in which the shoring is erected is also usually vertical or perpendicular. be.

On the other hand, if the ground surrounding the tunnel becomes relatively soft and it becomes difficult to obtain independence of the face, theoretically, if an oblique face is formed with an inclination angle, it becomes easier to obtain independence. However, with conventional shoring using shaped steel, it is difficult to follow the shape of the tunnel cavity and adjust length changes, so forming a diagonal face is rarely implemented, so instead of using this diagonal face. Generally, methods called ring cut method and core leaving method are used.

The above-mentioned ring cut method and core leaving method are methods in which only the periphery of the cavity is excavated vertically or vertically, leaving the center bottom of the face (the part called the large back or middle back). By leaving a part of the face, the same effect as slanting the face can be obtained, and an advanced hollow part (hereinafter referred to as
The shoring can be erected vertically or vertically within the ring cut section.

``Problems to be solved by the inventionj However, the above-mentioned ring cut method and core leaving method also have problems.
In reality, the following problems exist.

a. Because there is a residual part (core), spraying will interfere with the construction of concrete and rock bolts. In particular, since an attempt is made to obtain an average inclination effect for the entire face using the partially remaining portion, the distance between the tip of the face and the end of the partially remaining portion is larger than when the entire face is inclined.

b. The ring cut section has poor excavation efficiency, increasing excavation costs. In particular, in the case of mechanical excavation, some models may not be able to excavate, so models must be selected within a limited range or additional auxiliary machines may be required.

The C8 ring cut section is extremely narrow, making shoring work inefficient and dangerous.

d. Although there are some remaining parts, an average tilting effect is obtained as a whole, but since the face of the ring cut part is vertical or vertical, there is a risk of local face collapse, and in fact, There are many examples of this.

``Purpose j'' Therefore, the present invention has been made in view of the above, and has the ability to follow the shape of a tunnel cavity so that it can be easily and reliably built in an inclined shape along an inclined face surface, and The purpose of this invention is to provide a truss-type shoring whose length can be easily adjusted, and furthermore, to provide a tunnel excavation method that allows efficient shoring using this new truss-type shoring. The purpose is to

"Means for Solving the Problems" In accordance with the above-mentioned object, the structure of the present invention, which is summarized in the above-mentioned claims, has two parts curved along the cross-sectional shape of the tunnel excavation in order to solve the above-mentioned problems. A technical measure is taken in which more than one beam main material is placed side by side with a predetermined distance from each other, and each of the beam main materials is connected in a truss shape using a spiral lattice material.

Another configuration of the present invention is a technical measure characterized in that the truss type shoring is used as a reinforcing material for concrete lining.

Furthermore, another configuration of the present invention provides a technical means characterized in that the above-mentioned truss type support is used to excavate while being built in an inclined shape along the inclined face surface. There are many things.

Furthermore, another configuration of the present invention is a technical means characterized in that the above-mentioned truss type support is used to excavate while sequentially adding to the spiral along the spiral excavation face and building. There are things.

Therefore, since the truss type shoring of the present invention is composed of the main beam material and the spiral lattice material, the thickness and material of the main beam material and the lattice material, and the spiral span of the lattice material are set appropriately. This makes it possible to obtain the desired loading capacity and rigidity.

Moreover, the spiral truss structure has high rigidity in the torsional direction, and the truss type shoring of the present invention is not necessarily built on a single plane, but is built with some twist, so it can follow the shape of the tunnel cavity. It exhibits the effect of dramatically improving sex.

More specifically, the truss-type shoring of the present invention is prepared in such a way that the main beam material is curved into a circular, semi-circular (horseshoe shape, oval shape, hood shape), etc., but usually, consideration is given to transporting it into a tunnel. It is prepared by dividing it into multiple pieces. Each of these pieces is built into the excavated tunnel cavity along the inner surface of the cavity, and when a plurality of pieces are assembled, the outer circumferential shape is set to match the cross-sectional shape of the tunnel cavity. That is, when excavating a tunnel with a circular cross-sectional shape, the circular ring is divided into a plurality of shapes, and when excavating a tunnel with a quasi-circular cross-sectional shape, each shape is divided into a plurality of shapes, such as a horseshoe shape. However, this shape is not limited to the vertical cross section of the tunnel cavity, but may be one in which a diagonal cross section is divided into a plurality of parts, for example, in the case of a tunnel with a circular cross section, an elliptical ring can be divided into a plurality of parts. Furthermore, each piece may have a shape in which a spiral wire extending along the inner surface of the cavity is divided into predetermined lengths.

Therefore, when the truss type shoring of the present invention is erected, its outer circumference contacts the inner surface of the tunnel cavity and supports loads such as earth pressure, but the actual cross-sectional shape of the tunnel cavity does not always match the design. A certain amount of error occurs between this support and the cross-sectional shape of the tunnel cavity. In order to correct this error, in conventional shoring using shaped steel, adjustment pieces are inserted between the joints of each piece, or the ends of each piece are cut off and end plates are replaced. However, with the truss type shoring of the present invention, the desired rigidity can be obtained, so the erected truss type shoring is deformed using this rigidity to adapt to the cross-sectional shape of the tunnel cavity.

After adapting to the cross-sectional shape of the tunnel cavity, the truss type shoring is fixed as necessary, but if the truss type shoring is horseshoe-shaped, it may be fixed at both base ends to the foundation. In addition, it is possible to support loads such as earth pressure by connecting and fixing it to the existing supporting structure in the previous stage using a tie rod or the like, or by connecting and fixing it to a rock bolt (not shown) or the like.

In addition, since the truss type shoring of the present invention is composed of a beam main material and a lattice, concrete can be poured into the space surrounded by the beam main material, and if this truss type shoring is embedded in concrete, it can be used as reinforcing bar. It is something that exhibits an action.

"Embodiments" Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

In the figure, reference numeral 1 denotes a main beam member, and the main beam member 1 is made up of two or more main beam members curved along the cross-sectional shape of a tunnel excavation and arranged side by side at a predetermined distance from each other.

This beam main material l is usually constructed by curving round iron rods (the cross-sectional shape is not particularly limited to round) along the cross-sectional shape of the tunnel cavity, and when three or more are arranged side by side, they are not arranged in a straight line, but curved. The outer radii are larger and the inner radii smaller, and they are juxtaposed on concentric circumferences as shown most clearly in FIGS. 2 and 3. In the illustrated example, as most clearly shown in FIGS. 2 and 3, the main beam members 1 are arranged evenly on the same circumference, but the distances between them do not necessarily have to be the same.

The beam main material 1 may be formed to have a length covering the entire circumference of the tunnel cavity cross-section, that is, if the tunnel cavity cross-section is circular, it may be formed into a ring shape, and if it is horseshoe-shaped, it may be formed into a horseshoe shape. , pieces Al, A2. A3..., and each piece Al, A2. A3... has its curvature adapted to each part of the cross-sectional shape of the tunnel cavity.

The beam main members 1, 1, 1, . . . are connected in a truss shape using a spiral lattice member 2. This lattice material 2 is used for each beam main material 1 in the example shown in FIG. It is assumed to be a circular spiral inscribed in l, l..., but in thermal theory, each beam main material 1, 1.1...
It may be a circular spiral circumscribed by , or alternatively, an irregularly shaped spiral such as a triangular spiral as shown in FIG. 3 may be used. This lattice material 2 is also made of iron, and each beam main material l
The connecting portion is fixed by appropriate means such as welding. Moreover, as mentioned above, the whole is made of a plurality of pieces Al, A2. A3・
..., end plates 4 are provided at both ends to connect the pieces to each other. As this end plate 4 is most clearly shown in FIG.
or if necessary, the ends of the lattice material 2 are connected and fixed by welding or the like. In the illustrated embodiment, this end plate 4 has screw insertion holes 5 for fastening.
, 5.5... (see Fig. 9), and the two joined end plates 4°4 are inserted into the screw insertion holes 5, 5.5.
Although the two end plates 4, 4 may be welded together without using screws, there is no problem with the heat theory.

The truss-type shoring structure of the present invention having the above-mentioned structure is built along the inner surface of the tunnel cavity, and the following methods of building it are possible.

■Vertical erection This is the most basic erection method, and the truss type support AO is placed on a plane perpendicular to the tunnel center axis.

To further explain this vertical leverage based on the example in Fig. 4, the shoring AO is located on a plane perpendicular to the central axis of the tunnel T, and in the illustrated example, the cross-sectional shape of the cavity of the tunnel T is horseshoe-shaped. Therefore, the shoring AO is also shaped like a horseshoe. The horseshoe-shaped shoring AO may have both sides of its lower end connected by horizontal beams, but in the illustrated example, the end plates 4 at the lower end are each fixed to the base. It is a matter of fact that if the cross-sectional shape of the cavity is circular, the support AO should also be circular (hereinafter referred to as ring-shaped).

Also, this is common to the following erection methods, but in order to secure the erected shoring AO, connect it with the already erected shoring AO using tie rods 6 (only one tie rod is shown at one location in the figure). However, conventionally known methods can be used, such as connecting and fixing at multiple locations, or fixing to lock bolts (not shown), etc.

2. Diagonal construction In this diagonal construction, the shoring is erected on a plane that intersects with the tunnel center axis at a predetermined angle. There are two cases: one that slopes toward the right (referred to as left-right diagonal construction), and the other that slopes in the vertical direction (referred to as vertical diagonal construction).

2-1. Left and right diagonal erecting In this erecting method, the diameter of the shoring is set in advance to be slightly larger than the inner diameter of the tunnel cavity.
It is used when it is difficult to accurately determine the inner diameter of the tunnel cavity in advance, such as in areas where the extra trench must be enlarged. In other words, as shown in Fig. 5, when constructing the support AO on a plane that intersects the central axis of the tunnel T at a certain inclination angle in the left-right direction, by appropriately changing the inclination angle, an arbitrary tunnel cavity internal shape can be created. The aim was to match the size of the shoring AO to the following.

With conventional shoring made of shaped steel, the shape of the shoring cannot follow the change in the cross-sectional shape of the tunnel due to the change in the inclination angle mentioned above. However, this construction method has not been adopted because the shape of shaped steel cannot be easily changed, whereas the curvature of a local part changes.However, if the shoring of the present invention is used,
It is also possible to change the circular support AO, which has a diameter larger than the inner diameter of the tunnel T, into an elliptical shape and use it in the illustrated tunnel T having a circular cross section.

2-2. Undersoil diagonal construction In this construction method, the position of the shoring is inclined vertically with respect to the central axis of the tunnel, and is most suitably used when excavating a tunnel with an inclined face.

3゜As mentioned above, if the ground around the face is soft, it is easy to obtain independence by forming a diagonal face with an inclination angle, and as shown in Fig. 6, the diagonal face 7
In this case, tunnel T is often excavated in
If the shoring AO is to be built at the leading edge of the diagonal face 7, it is most efficient to install the shoring AO diagonally up and down along the diagonal face 7 as shown in the figure.

In this case, with conventional shoring using shaped steel, the shape of the shoring cannot follow the change in the cross-sectional shape of the tunnel cavity due to changes in the inclination angle, as is the case with left and right diagonal construction, so this construction method has not been adopted. .

Spiral construction There are two types of spiral construction: one is to build each ring separately and sequentially (referred to as twist construction), and the other is to connect the rings one after another (referred to as spiral construction).

3-1. Twisted construction The shoring of the present invention takes advantage of the property of being easily deformed in the torsional direction, and as shown in Figure 7, the shoring AO is not placed on a single plane, but is erected with twisting. By changing this twist amount, the support A can be adjusted to the hollow cross-sectional shape of the tunnel T.
This is to follow the shape of O. In the illustrated example, the hollow cross-sectional shape of the tunnel T is horseshoe-shaped, and the - of the lower left and right ends of the shoring AO is moved in the front-rear direction to impart twist.

3-2. Spiral erecting This erecting method is a development of the above-mentioned twist erecting. A3...
・is constructed by sequentially connecting them in a spiral shape, and is suitably used for spiral excavation, which will be explained later.

4.Other erection methods Other than the above-mentioned methods of erecting the shoring AO, it is also possible to use a method that combines tilting and twisting.

By erecting the shoring AO of the present invention as described above, the following tunnel excavation method can be proposed.

In other words, one tunnel excavation method involves arranging two or more main beam members curved along the cross-sectional shape of the tunnel excavation with a predetermined distance from each other, and connecting each of the main beam members in a truss shape using a spiral lattice material. This truss-type shoring is used to support a tunnel during excavation, and is characterized in that the truss-type shoring is used as a reinforcing material to line the tunnel with concrete. This concrete lining corresponds to figure 3.
This is carried out by a conventionally known method, and can be carried out by concrete spraying or by pouring concrete using a formwork (not shown).

Next, another tunnel excavation method involves arranging two or more main beam members curved along the cross-sectional shape of the tunnel excavation with a predetermined distance from each other, and forming each of the main beam members into a truss-like structure using a spiral lattice material. The truss-type shoring structure is constructed so that the truss-type shoring structure is constructed so as to be erected in an inclined manner along the sloping face surface while being excavated.

As mentioned above, it is clear that in the case of an inclined face, it is most desirable to erect the shoring at an angle along the inclined face. However, when the inclination angle of this diagonal face changes, it was impossible to make the shape follow the shape of the tunnel cavity with conventional type steel supports, but with the use of the present invention support, it is possible to follow this shape. becomes. In other words, even if the inclination angle of the face or the inclination angle of the shoring changes somewhat, the shape of the shoring of the present invention can match the shape of the tunnel cavity due to its rigidity.

When the angle of this diagonal face 7 changes, there arises a problem in not only the followability of the shape but also the length adjustment of the support AO. That is, in the horseshoe-shaped tunnel T shown in FIG. 6, if the inclination angle of the shoring AO is changed, the lower ends of the shoring AO may no longer match the tunnel floor F.

In this case, it is necessary to cut or add the support (defective structure AO), but with conventional shaped steel, it is not easy to cut the middle, but with the support of the present invention, as shown in Figure 9, Since the beam main material 1 (and the lattice material 2) are linear, it is easy to cut them in the middle or connect them by welding. If the length is to be shortened, the beam main material 1 may be further cut to a desired dimension, and if the length is to be increased, a beam material (not shown) of the desired length may be inserted and welded. In the case where the AO is installed diagonally and the end plate 4 is to be reattached at a certain angle to the support AO, the connecting position of each of the beam main members 1 may be shifted.

Furthermore, yet another tunnel excavation method using the shoring of the present invention includes arranging two or more beam main members curved along the cross-sectional shape of the tunnel excavation with a predetermined distance from each other.
The truss-type shoring system, which is made by connecting the main beam members in a truss-like manner using spiral lattice materials, is characterized by the fact that the truss-type shoring system is successively added to the helical support along the spiral excavation face surface, and the excavation is carried out while being erected. .

Here, spiral excavation does not involve excavating the entire surface of the face at the same time, but instead divides the face 7 into predetermined fan sections and excavates these fan sections in a spiral manner.Currently, some shafts are manually excavated. It has a proven track record in semi-mechanical or semi-mechanical digging, but in the future it is expected to be applied to horizontal shafts, inclined shafts, and even mechanical mining. Therefore, when carrying out such spiral excavation, since the supporting structure AO of the present invention has the property of being able to be deformed greatly in the torsional direction, arc-shaped pieces Al, A2. A3... (which may be formed to have a twist in advance) may be prepared and then connected and built in sequence during spiral excavation.

``Effects of the Invention j The present invention is as described above, and the shoring of the present invention comprises two or more main beam members curved along the cross-sectional shape of a tunnel excavation, arranged side by side with a predetermined spacing between each main beam member. Since they are connected in a truss shape using spiral lattice material, a predetermined load capacity and rigidity can be obtained, and it is possible to provide a truss type support that can follow the cross-sectional shape of the tunnel cavity. .

In addition, the spiral lattice material in particular has a high degree of shape changeability in the torsional direction, which is a contradictory requirement in some respects of loading capacity and shape followability. It is possible to provide truss-type shoring that can be handled by

In addition, since the shoring method of the present invention uses the above-mentioned truss-type shoring, it has developed the shoring work philosophy pursued by the NATM method, which rationally follows the shape of the tunnel cavity and provides the necessary shoring at the necessary locations. , it is possible to provide a cutting method that makes it possible to immediately and easily erect shoring at an excavated site.

[Brief explanation of drawings]

Fig. 1 is a front view showing one embodiment of the truss type shoring of the present invention, Fig. 2 is a sectional view taken along line A-A, Fig. 3 is a sectional view of the shoring in another embodiment, and Fig. 4 is a main A vertical cross-sectional view of a tunnel being excavated using the excavation method using the invention shoring, FIG. 5 is a cross-sectional view of a tunnel being excavated using another excavation method, and FIGS. 6 to 8 are each a further different excavation method. FIG. 9 is an enlarged perspective view of the end of the shoring. 1 - Beam main material 2 - Lattice material 3 - Concrete lining 4 - End plate 5 - Screw insertion hole 6
〜Tie rod 7〜Face 7゛〜Slanted face
AI, A2゜A3 ~ piece AO ~ shoring T
~Tunnel ~Floor

Claims (4)

[Claims] (1) Truss type in which two or more main beam members curved along the cross-sectional shape of the tunnel excavation are placed side by side at a predetermined distance from each other, and these main beam members are connected in a truss shape with a spiral lattice material. Shoring. (2) Truss type support made by arranging two or more main beam members curved along the cross-sectional shape of tunnel excavation with a predetermined distance from each other, and connecting each of the main beam members in a truss shape with a spiral lattice material. A tunnel excavation method characterized by supporting the tunnel during excavation, and lining the tunnel with concrete using the above truss type shoring as reinforcing material. (3) Truss type support made by arranging two or more main beam members curved along the cross-sectional shape of the tunnel excavation with a predetermined distance from each other, and connecting the main beam members in a truss shape with a spiral lattice material. A tunnel excavation method characterized in that the tunnel is excavated while being built in an inclined manner along the sloping face. (4) Truss type support made by arranging two or more main beam members curved along the cross-sectional shape of tunnel excavation with a predetermined distance from each other, and connecting each of the main beam members in a truss shape with a spiral lattice material. A tunnel excavation method characterized by excavating while building the tunnels by adding them in a spiral along the spiral excavation face.