JPH0586800A - Method of constructing assembly of steel timbering for tunnel and spacer fixture - Google Patents

Abstract

PURPOSE:To prevent inferior filling by attaching spacers to a timbering made of an H-like steel bar or the like so as to define a gap between the timbering and an excavated surface in the natural ground, and by filling shotcrete in the gap. CONSTITUTION:An H-like steel bar is curved so as to form a steel timbering 1 having its outer peripheral surface formed by one of the flange surfaces of the H-like steel bar. Spacer fixtures 2 each having a projection at the upper part thereof and fixing end parts and formed of a resilient rod-like member are provided to the upper part of the timbering 1. The spacer fixtures 2 are resiliently fixed to the flange of the timbering 1 so as to define a gap 5 between the excavated surface 6 and the timbering 1 when the timbering 1 is installed to an excavated surface 6 in the ground. Further, in a condition such that shotcrete 7 is sufficiently filled in the gap, a spraying process is carried out. Various kinds of spacer fixtures having projections with different heights and having different shapes and so forth, are provided, being adapted to be used in accordance with a condition of a job site. With this arrangement, a timbering is installed in accordance with a disorder of an excavated surface, and concrete can be sufficiently filled, thereby it is possible to enhance the strength and corrosion resistance thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to NATM (New Austri
an Tunneling Method) A construction method for a tunnel support method represented by the construction method and a spacer member that assists this method. In particular, at the time of construction, a spacer member is used between the ground excavation surface and the steel support method. Construction of steel support for tunnels that creates a gap to ensure the filling of sprayed concrete and evenly transmits the ground load to the steel support through sprayed concrete. Includes embedded construction method and spacer fittings.

[0002]

2. Description of the Related Art The NATM method is a method of excavating a tunnel, in which a steel support work is built, followed by sprayed concrete construction and rock bolt construction, and the ground excavation is formed sequentially for each predetermined length of excavation. It is a tunnel construction method in which the surface is supported by these support materials and the excavation of the tunnel is promoted while making use of the strength of the ground, and it is known as a construction method that has been widely adopted in recent years.

The standard construction procedure is (a) excavation, (b)
Primary shotcrete construction [can be omitted], (c) Steel support, (d) Wire netting [can be omitted], (e) Secondary sprayed concrete construction, and (f) Rock bolt construction However, there may be changes in procedures such as omission. Here, the steel support is generally made by bending an H-shaped steel (hereinafter referred to as "H-shaped steel support"), and the outer peripheral flange surface is formed along the ground excavation surface to form an arc or arch. The supporting members are circumferentially arranged, are installed at a predetermined interval in the length direction of the tunnel, and the supporting members adjacent in the length direction are connected by a connecting member.

[0004] Shotcrete concrete construction is carried out by a primary shot concrete construction (which can be omitted) and a secondary shot, in which a quick-setting concrete is sprayed so as to cover the ground excavation surface and the ground excavation surface and the H type steel support It consists of concrete construction, and the rock bolt construction is construction to place it in the support work or at an intermediate position between the adjacent support works before and after the steel support work is built or after the concrete has been hardened by spraying. It forms a reinforcing wall for supporting. Also, the final concrete lining is the wall formation of the tunnel called "concrete winding".

[0005]

However, the conventional H-shaped steel supporting work has the following problems in construction. When building H-shaped steel supports, it is a rule to build them in contact with the natural ground, but even if the primary shotcrete (optional) is constructed, it will be installed closely due to the irregularity of the excavated surface. It is difficult to do so, and for this reason, FIG. 6 (a partial explanatory view showing the construction state) and FIG. 7 (an explanatory view of the construction cross section)
As shown in (1), in the sprayed concrete construction, a void (nest) where the concrete was not filled was left between the ground and the ground in the vicinity of the contact surface of the upper flange of the H-shaped steel support.

[0006] This void gives a disadvantageous condition to the uniform transmission of the ground load to the supporting work and causes the loosening of the ground together with the existence of the void itself, which may cause a structural defect of the supporting work. there were. Further, the supporting members may be exposed to the spring water generated in the voids and corroded and deteriorated to synergize with the above defects. Therefore, considering the above risks in the design of the shoring work, there are inevitable structural disadvantages,
The waste here was unavoidable.

[0007] With only H-shaped steel support, even if the above-mentioned defective filling of the sprayed concrete on the rear surface of the flange (contact surface with the natural ground) is attempted to be eliminated by working, the gap between the natural ground surface and the flange surface is In some cases, there was a three-dimensional obstacle in the construction of sprayed concrete, and even with careful spraying work, the gap could not be filled, and the actual condition was to leave it alone.

The present invention has been made in view of the above circumstances, and a significant gap is provided in advance between the ground excavation surface and the steel support structure to ensure the filling of shotcrete. It is an object of the present invention to provide a method of constructing a steel support for a tunnel that can be reinforced to contribute to the improvement of the ground and a spacer fitting that assists the method.

[0009]

In order to achieve the above object, one of the present inventions is, in part, a method of constructing a steel support for a tunnel. When constructing a tunnel support that supports a surface, a spacer member made of a rod-shaped material is attached to the steel support work between the steel support work having a flange and the ground excavation surface, and a gap is formed. Is formed, and the gap is filled with shotcrete.

A spacer metal fitting made of a rod-shaped material for supporting a steel support having a flange as an auxiliary member of the above-mentioned construction method, wherein the steel fitting is made by the restoring force generated by the deformation resistance of the worked and formed member. It has a fastening end that holds the upper flange edge of the shoring and a protrusion that contacts the ground excavation surface and forms a gap between it and the steel shoring. It is characterized by being.

[0011]

According to the construction method of the present invention and the spacer metal fitting that assists the method, since the ground metal comes into contact with the ground surface through the protrusion provided on the spacer metal, A gap is secured between them.

[0012] This gap advantageously responds to the irregularity of the excavated surface, and contributes to the securing of the filling property of the quick-setting concrete in the spraying concrete construction to eliminate the filling failure.

[0013] As a result, the steel supporting work comes into contact with the ground evenly through the shotcrete, avoiding the concentration of the ground load on the steel supporting work and the steel supporting work. It contributes to the effective exertion of the load bearing capacity of. Also,
Steel shoring is covered with shotcrete, which improves corrosion resistance. Further, since there is no gap between the steel support and the ground, it is useful for preventing the ground from loosening.

On the other hand, since the spacer metal fittings are detachable, they can be easily mounted on the steel shovel construction site, so the spacer metal fittings (height of the metal fittings) and the number of used metal fittings can be selected according to the situation of the excavated surface. You can choose.

[0015]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an explanatory view of a construction (part) of a steel supporting work to which a spacer fitting is attached, and FIG. 2 is
It is a construction cross-section explanatory drawing of steel support similarly. Where 1
Are steel supports, 2 are spacer fittings, 3 are upper flanges, 4
Is a lower flange, 5 is a gap, 6 is a ground (ground excavation surface), 7
Is shotcrete and 8 is a rock bolt.

As shown in FIG. 1, when the steel support bar (1) is installed, the H-shaped steel is curved, and the spacer fittings (2) are provided at both ends of the upper flange (3) surface which is the outer circumference. .. At this time, the spacer fitting (2) has a spring-like tightening action due to the deformation resistance of the member and is fixed to both ends of the surface of the flange (3). Using the spacer metal fitting (2) as a contact point, the above-mentioned shaped steel is provided along the ground excavation surface (6) and circumferentially provided in an arch shape to form a steel support bar (1).

Further, FIG. 2 schematically shows a state in which the shotcrete (7) is filled as an explanation of the construction section, but the spacer metal fitting (2) is an upper flange of the steel support bar. Since a gap is formed between the (2) surface and the ground excavation surface (6), it is possible to advantageously deal with irregularities on the excavation surface and to eliminate defective filling of shotcrete. Is.

Here, the condition that the spacer metal fitting (2) has is that it can be attached and detached, and when the steel support (1) is to be built, the shotcrete concrete must meet the condition of the unevenness of the ground (6). Any material may be used as long as (7) is made of an elastic material having strength and rigidity capable of maintaining a gap to be surely filled. The usage conditions of the spacer metal fittings (2) may be appropriately determined according to the ground conditions and the construction conditions, but the intervals between them are about several tens of cm to 100 cm, and the load bearing capacity is a level that can support the load of floating stones. Become.

As described above, the characteristic feature of the present invention is that
A clearance (5) is secured between the ground (6) and the surface of the upper flange (3) of the steel supporter (1) via a detachable spacer fitting (2). Therefore, a specific example of the spacer fitting provided by the present invention will be shown and described.

As shown in FIG. 3, here, a round bar is machined to form a protrusion (9), and a fastening end (1
It is preferable that (0) is configured to hold the flange of the shape steel, and the gripping or tightening action generated by the deformation resistance of the material of which the shape steel has is utilized. The reason is that workability in application (attachment / detachment) and adjustment of the contact point is required at the industrial site.

As shown in FIG. 4, upon application, one of the fastening end portions (10) is hooked on the edge of the upper flange (3) of the steel support bar (1) and can be locked to the flange by a hammer or the like. If the other end of the fastening (10) is hit to the position where it can be locked to the edge of the other upper flange (3), tap this fastening end (10) again and slant it to the flange. Attach at the position. For desorption, this operation may be performed in reverse.

When the actual tunnel excavation cross section has an excess over the designed cross section diameter, if various spacer fittings having different protruding heights of the spacer fittings are prepared in advance,
It can be dealt with by using them properly.

Therefore, it is a good idea to prepare a plurality of types of spacer fittings having different heights and shapes so that they can be used for a wide range of steel support construction conditions, and to use them in accordance with site conditions. FIG. 5 shows another embodiment of the spacer fitting manufactured in consideration of various usage conditions. Here, FIG. 5A shows that the fastening end portion (10) is formed in a “hump” shape to improve workability and the like.
(B) is intended to improve workability by the rod-shaped plate material.

FIG. 6 and FIG. 7 are explanatory views of a building construction (part) and a construction cross section of a conventional H-shaped steel supporting work,
In comparison with the present invention, in the H-shaped steel supporting work, the problem that the filling failure of the shotcrete occurs near the contact surface between the upper flange surface and the ground excavation surface and the void (11) is generated is pointed out. Is. That is, the void portion (11) is an installation structural defect due to the direct construction of the H-shaped steel support structure, not the skill of the shotcrete construction, and is unavoidably generated.

[0025]

EFFECTS OF THE INVENTION The present invention has the above-described structure, and by the steel supporting work to which the spacer metal fitting is attached and the detachable spacer metal fitting, a gap is formed between the ground excavation surface and the steel supporting work. Is provided to deal with the irregularity of the excavation surface when constructing the steel shoring, and during the construction of the spray concrete, the defective filling of the spray concrete is eliminated and the steel shoring works effectively. be able to.

That is, the steel support bar comes into contact with the ground evenly through the shotcrete, thereby avoiding the concentration of the rock load on the steel support bar and the effect on the steel support bar. This contributes to the effective utilization of the bearing capacity of the support work. In addition, the steel supports are covered with shotcrete, which improves the corrosion resistance. Further, since there is no gap between the steel support and the ground, it is useful for preventing the ground from loosening.

On the other hand, since the spacer fitting of the present invention is detachable, it can be easily installed at the construction site of steel supporting work, and therefore the shape of the spacer fitting (height of fitting) according to the situation of the excavation surface. And the number of uses can be selected. Further, the elasticity of the spacer metal fittings has an advantageous effect on the installation of the steel support structure. Furthermore, the steel support and spacer fittings can be transported and handled separately,
Spacer brackets will not hinder the transportation and handling of steel supports.

Within the range in which the spacer fitting of the present invention is protected, its modification is free, and it has the strength and rigidity to maintain the gap that can be surely filled with the shotcrete when the steel support is installed. Any elastic material may be used, and the shape of the spacer fitting including the attachment / detachment device is not particularly limited.

[Brief description of drawings]

FIG. 1 is a partial explanatory view of a construction method showing an embodiment of the present invention.

FIG. 2 is an explanatory view of a construction section of the steel support work.

FIG. 3 is an explanatory view of a spacer fitting showing an embodiment of the present invention.

FIG. 4 is an explanatory view of the mounting of spacer fittings.

5 (a) and 5 (b) are explanatory views of a spacer fitting showing another embodiment of the present invention, in which (a) is a "bump" -shaped fastening end and (b) is a rod-shaped plate. It was done.

FIG. 6 is a partial explanatory view of a construction method of a conventional H-shaped steel support work.

FIG. 7 is an explanatory view of a construction cross section of an H-shaped steel support work.

[Explanation of symbols]

 1 Steel support 2 Spacer member (spacer metal fitting) 3 Upper flange 4 Lower flange 5 Gap 6 Ground (ground excavation surface) 7 Shotcrete 8 Rock bolt 9 Projection 10 Fastening end 11 Void (nest)

Claims (2)

[Claims] 1. A construction of a rod-shaped material between a steel support bar having a flange and a ground excavation surface in construction of a tunnel support structure which supports the ground excavation surface by steel support and shotcrete. A method for building a steel support bar for tunnels, characterized in that the spacer member manufactured in (1) is attached to the steel support bar to intervene to form a gap, and this space is filled with shotcrete. 2. A spacer member made of a rod-shaped material to be applied to a steel support having a flange according to claim 1, wherein the steel support is provided by a restoring force generated by deformation resistance of the processed and formed member. It has a fastening end that holds the upper flange edge of the work, and a protrusion that contacts the ground excavation surface and forms a gap between the steel support work, and its application is removable. Spacer metal fittings characterized in that there is.