JPH0913884A - Primary lining method for tunnel - Google Patents

Abstract

PURPOSE: To perform a primary lining work with high workability and reliability even for the un-consolidated natural ground by providing an auxiliary form mounted on a spray machine at such a position on the surface of the natural ground as corresponding to the thickness of sprayed concrete. CONSTITUTION: An auxiliary frame K is laid at such a position on the surface of the natural ground G of an excavated tunnel T as corresponding to the thickness of sprayyed concrete C for primary lining. In this case, the form K is mounted on the articulated arm 120 of a self-traveling spray machine 100 used to support the concrete spraying nozzle 100 thereof, via a jointing member 50 having a hinge mechanism. Also, a support is laid between the form K and the surface of the natural ground G, thereby fixing the form K. Thereafter, concrete is sprayed from the nozzle 110 of the machine 100 to space between the surface of the natural ground G and the form K.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for constructing a tunnel for railroads or roads, in particular, a mountain tunnel construction method, in which the ground surface of an excavated tunnel is first lined with sprayed concrete.

[0002]

BACKGROUND OF THE INVENTION As one of mountain tunnel construction methods, there is a construction method generally called NATM (NATM). This construction method is a construction method in which rock bolts, shotcrete, steel arch support, etc. are supported individually or in combination depending on the condition of the ground. Therefore, compared to conventional steel arch supports and conventional construction methods that use sheet piles, for example, it can handle a wide range of rocks from earth and sand to hard rocks.
It is easy to take waterproof measures and has advantages such as being advantageous in maintenance.

In this NATO method, concrete is sprayed on the ground surface of the excavated tunnel to make a primary lining, thereby preventing the ground from collapsing. At that time, the ground on which concrete is sprayed is, for example, unconsolidated ground (bad ground, low-strength ground).
In the case of, the wire mesh is often used to improve the adhesive strength of the sprayed concrete. This wire mesh is used
This is to prevent the soil particles on the ground surface from being blown away as much as possible by the force of spraying concrete.

[0004]

However, it has been found that such a method of spraying concrete using a wire net causes an unfavorable problem. That is, when the sprayed concrete blows off the soil particles, a part of the soil particles piles up on the wire mesh, and the sprayed concrete adheres to them, forming a lining (primary lining) while leaving voids. Is. In such a case, a considerable amount of backfilling injection is required, even though one of the features of Nathom is that the sprayed concrete adheres to the ground and does not require backfilling injection. . This backfilling operation is not preferable because it involves danger and uncertainty.

Therefore, the inventor of the present application has an idea to prevent the soil particles from being blown off at all. For example, a temporary auxiliary formwork is arranged at a position corresponding to the spraying thickness of sprayed concrete, and concrete is placed therein. I thought about spraying. It can be seen that this method gives very good results, since there is an auxiliary formwork that holds the surface side of the shotcrete. However, when considering the workability of the entire primary lining, the workability for arranging the auxiliary formwork must be sufficiently dealt with.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and by using an auxiliary formwork at the time of spraying concrete, even the unconsolidated ground is primarily covered with sprayed concrete. It is an object of the present invention to provide a technique capable of improving the workability and reliability for construction and also improving the workability for arranging the auxiliary formwork.

[0007]

In the primary lining method of the tunnel of the present invention, as shown with reference to FIG. 1 corresponding to the embodiment, the surface of the ground G of the excavated tunnel T is blasted with concrete C The method of using the self-propelled spraying machine 100 for spraying the concrete C at the time of the primary lining is adopted. In that case, the first step of arranging the auxiliary form K at a position corresponding to the spraying thickness of the concrete C for the primary lining, and the space between the auxiliary form K and the surface of the ground G. And a second step of spraying concrete C against. And the auxiliary form K
In the first step of arranging, the auxiliary form K is attached to a part of the spraying machine 100.

Here, without directly spraying concrete C onto the surface of the natural ground G, the auxiliary form K and the natural ground G are used.
It is desirable to spray concrete C in a direction along the surface of the natural ground G in the space between the surface and the surface of the concrete C. This is because, when the natural ground contains unconsolidated soil particles, the soil particles can be prevented from being blown off by the force of spraying the concrete C.

As the self-propelled spraying machine 100,
It is preferable to use one having an articulated arm 120 that supports a nozzle 110 for spraying concrete C.
This is because the auxiliary formwork K can be attached to the articulated arm 120 by using the articulated arm 120 itself as a support. By doing so, the power of the spraying machine 100 can be used to place or move the auxiliary mold K at an arbitrary position. Further, a means for adjusting the inclination of the auxiliary form K, for example, one of the connecting members 50 for connecting the multi-joint arm 120 and the auxiliary form K, so that the arrangement position of the auxiliary form K can be set favorably. It is also preferable to provide a hinge mechanism 55 on the part.

At the time of spraying the concrete C, it is desirable to place a release sheet S on the inner surface of the auxiliary form K. This release sheet S exerts a function of separating it from the sprayed concrete C when the auxiliary form K is released from the mold. Further, it is desirable to dispose a supporting structure 10 for fixing the auxiliary mold K between the surface of the natural ground G and the auxiliary mold K. That way, the support 1
The auxiliary form K can be easily attached using 0. Moreover, the support work 10 itself is sprayed on the concrete C
The primary lining can be embedded inside the primary lining to provide a reinforcing material-containing primary lining.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. The embodiment shown in these figures shows an example in which the present invention is applied to construct a tunnel by the NATM method. Therefore,
For example, when the ground G of the excavated tunnel is a hard rock, the surface of the ground G is directly blasted with concrete, and if necessary, a rock bolt is applied to carry out the primary lining. When the natural ground G becomes unconsolidated natural ground such as earth and sand on the way, when the sprayed concrete C is constructed, the special auxiliary mold K as shown in the drawing is used.
And using the spraying machine 100.

Here, before explaining the construction procedure of the sprayed concrete C, regarding the construction of the specially-designed auxiliary form K and the spraying machine 100, and the correlation between the two,
First, a description will be given. The spraying machine 100 is a generally known self-propelled machine, and has a multi-joint arm 120 that supports a concrete spraying nozzle 110 at its tip. The articulated arm 120 is, in order from its base end,
The nozzle 110 that includes the first rod 121, the second rod 122, the third rod 123, the fourth rod 124, and the fifth rod 125, and that is supported by the tip (fifth rod 125) portion, It can be moved three-dimensionally, such as in the circumferential direction of the tunnel, in the axial direction, and vertically and horizontally. The auxiliary form K is detachably attached to the multi-joint arm 120 for use. As a specific mounting position, a rod near the nozzle 110, in the illustrated example, the third rod 1
It is attached to the portion 23 through a connecting member 50. This connecting member 50 has a horizontal portion 51 and a vertical portion 52,
A hinge mechanism 55 for adjusting the inclination of the auxiliary form K is provided between them.

When arranging the auxiliary form K, the auxiliary form K is moved by utilizing the power of the wheels 101 of the spraying machine 100 or the multi-joint arm 120, and as shown in FIG. Place it away from the surface of the. When arranging the auxiliary form K, a plurality of supporters 10 are built in which the auxiliary form K can be fixed to the required position while being fixed thereto. As the support work 10, H steel is used here. This is because in the case of H steel, it can be advantageously developed in terms of strength and workability of attaching the auxiliary formwork K described later. The supporting members 10 are arranged so as to extend in a curved shape in the circumferential direction of the tunnel and have a space in the axial direction of the tunnel. Then, the part of the mold body 20 of the auxiliary mold K is detachably attached to these supporters 10 and 10 using the attaching means 30.

The layout position of the mold body 20 is set so as to correspond to the spray thickness of concrete for the primary lining. Therefore, the built-in position of the supporting work 10 should be considered so as to substantially match the setting. Of course, it is not necessary to set it in a strict sense, and there is no problem even if there is some error. Along with the work of attaching the mold body 20, the release sheet S is arranged on the inner surface thereof. This release sheet S is
For example, it may be pasted on the inner surface of the form body 20 using a double-sided tape or the like. Further, as shown in FIG. 2, it is also preferable to support both ends of the release sheet S so as to be sandwiched between the supporting member 10 and the mold body 20. Further, as the release sheet S, one wound in a roll shape as shown in the figure is used, and if it is arranged such that it is extended as the auxiliary form K is assembled upward, The workability can also be made extremely excellent. At that time, it is very convenient to place the roll-shaped portion S1 of the release sheet S on the horizontal portion 52 of the connecting member 50.

The mounting means 30 may be a combination of general bolts and nuts, but a wing nut is preferable in consideration of mounting workability. In that case, a backing plate 12 may be used so that it can be easily attached to the flange 11 portion of the support structure 10 made of H steel.

After assembling the auxiliary form K in this way, concrete C is then sprayed by the spray nozzle 110 into the space between the auxiliary form K and the ground G.
When the concrete C is sprayed, it is preferable not to spray it directly on the surface of the natural ground G.
That is, as shown in FIG. 2, the spray is applied in the direction along the surface of the natural ground G (for example, downward). By doing so, the concrete C can be sprayed while the soil particles of the natural ground G are not completely blown away.

The concrete C sprayed by the nozzle 110 densely fills the space between the ground G and the auxiliary form K, and sequentially forms a primary lining. Therefore,
The primary lining thus formed adheres sufficiently to the surface of the ground G by the function of the auxiliary form K, and forms a good concrete layer. After the predetermined strength of the sprayed concrete C has been developed or after it has been hardened, the auxiliary form K is removed from the supporting structure 10 and reused at the next construction site. At this time, since the release sheet S is provided on the inner surface of the mold body 20 that constitutes the main body of the auxiliary mold K, the mold body 20 portion can be easily demolded. Further, since the demolding work and the work for moving the auxiliary mold K can be performed by using the spraying machine 100, the workability thereof can be remarkably improved.

On the other hand, paying attention to the constructed primary lining, a plurality of supporters 10 are embedded in the interior, and therefore each supporter 10 functions as a so-called reinforcing steel material. .

By adopting the above construction method,
When the concrete C is sprayed, by using the auxiliary form K and the spraying machine 100 that supports it, it is possible to improve the workability and reliability of the primary lining with sprayed concrete even for unconsolidated ground. And then
Moreover, it is possible to provide a technique for improving workability for arranging the auxiliary mold K. In the embodiment, concrete is sprayed onto the space between the ground surface and the auxiliary formwork, but of course, it may be sprayed directly depending on the state of the ground. It is also possible to simply pour concrete instead of sprayed concrete.

[Brief description of the drawings]

FIG. 1 is a partial sectional side view showing an embodiment of the present invention.

FIG. 2 is a perspective view of a main part showing an embodiment of the present invention.

[Explanation of symbols]

 K Auxiliary formwork G Ground C Concrete S Release sheet 10 Supporting work 20 Formwork body 30 Mounting means 100 Spraying machine 110 Nozzle 120 Multi-joint arm

Claims (4)

[Claims] 1. A method of using a self-propelled spraying machine for spraying concrete when performing primary lining on the ground surface of an excavated tunnel with sprayed concrete. Including a first step of arranging the auxiliary formwork at a position corresponding to the spraying thickness of the concrete, and a second step of spraying concrete onto the space between the auxiliary formwork and the ground surface, and In the first step of arranging the auxiliary mold, the auxiliary mold is attached to a part of the spraying machine to perform the primary covering method of the tunnel. 2. The self-propelled spraying machine comprises an articulated arm supporting a nozzle for spraying concrete,
The primary lining method of the tunnel according to claim 1, wherein the auxiliary formwork is detachably attached to the articulated arm. 3. The articulated arm and the auxiliary formwork are connected via a connecting member, and a part of the connecting member is
The primary lining method of the tunnel according to claim 2, wherein there is a hinge mechanism for adjusting the inclination of the auxiliary formwork. 4. The primary lining method for a tunnel according to claim 1, wherein a supporting work for fixing the auxiliary formwork is arranged between the ground surface and the auxiliary formwork.