JPH0416622A - Protective structure of underground structure made of concrete and construction method thereof - Google Patents

Abstract

PURPOSE:To protect the structure against the shock caused by the explosion in the inside by burying concrete flat plates in vertical lines between the upper face plates of a concrete cubicle and pavement during the backfilling in open shield construction. CONSTITUTION:A shield machine is advanced to dig and properly bury the surface of an existing underground structures 4, which are arranged in a line, and pavement 6 is constructed on the surface, that is, open shield construction method. When the surface is buried in open shield construction method, concrete flat plates 8 is arranged in a vertical line between the surface plates 1a of a concrete cubicle 1 and the pavement 6 along the surface plates 1a. When the concrete cubicle recives the shock caused by explosion or the like in the inside, the shock can be eased by making the cushion material work to the back filing sediment 5 pressed by the concrete flat plates 8.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a concrete underground structure when constructing underground passages for water supply and sewage systems, public drains, telegraph, telephone, etc. in urban areas using concrete boxes. It concerns the protective structure of objects and its construction method.

[Prior art] There are various construction methods for constructing underground structures using concrete bodies with a rectangular cross section, but the so-called open-cut construction method involves sequentially excavating from the ground surface and suspending a concrete box. (open construction method) and a propulsion method in which a starting shaft is built and concrete boxes are pushed into the ground one after another.

In either construction method, the concrete box 1 used is the 6th
As shown in the figure, the outer periphery includes a top plate 1a, a left side plate 1b, a right side plate 1c, and a bottom plate 1d, all of which are flat, and each has a corner 2 where these plates intersect at right angles.

In principle, the internal hollow penetrating portion 3 has a rectangular cross section, but the corners are often beveled and formed as corbels.

Such concrete boxes 1 are arranged in columns, fitted with steel collars at their mutual connections, and provided with small through holes extending through the walls in the length direction, in which steel rods or plating are inserted.
Insert tension material such as CAIS and secure it under tension.

Incidentally, the size of the concrete box 1 varies to some extent, but the largest ones are about several meters in height and width.

[Problem to be solved by the invention]

When an underground structure such as an underground passage is constructed in a city area using such a concrete box l, the hollow penetration part 3 becomes a pedestrian or roadway, but if a bomb is planted inside due to a bomb attack or the like,
If this explodes, cracks will appear in the top plate 1a, left side plate 1b, right side plate 1c, and bottom plate 1d of the concrete box 1.
Becomes fragile.

The concrete box 1 is buried underground, and its surroundings are in contact with the ground, so the left side plate 1b and the right side plate IC
If a crack occurs in the bottom plate 1d, it will hardly be a problem.

However, if the concrete box 1 is constructed as an underground structure at a relatively shallow depth under the road surface,
If the top plate 1a is cracked, there is a risk that the top plate 1a will collapse due to the load of vehicles and other means of transportation passing on the road surface, which may lead to the collapse of the surface road.
cause havoc.

The present invention solves the disadvantages of the conventional example and provides a protective structure for a concrete underground structure and its construction method that can prevent the top plate of a concrete box from collapsing due to internal impact such as explosion. be.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a propulsion jack in a shield machine with openings on the top and front sides, excavates from the front of the shield machine or the top of the front part, and excavates the concrete box that follows. The shield machine is advanced by a propulsion jack using the reaction force of the existing underground structure, and as the shield machine moves forward, a new concrete box is lowered from the upper surface of the rear part of the shield machine and placed in the front row of the existing underground structure, and the same goes for the following. In the open shield construction method, a shield machine is repeatedly used to excavate, and the upper surfaces of existing underground structures that are arranged in tandem are backfilled as appropriate, and the upper surface is paved with road surface. The gist of this method is to sequentially bury concrete flat plates in a vertical line between the face plate and the road pavement, lining up with the top plate.

[Effect]

According to the present invention, in the event of an explosion, the top plate of the concrete box receives the impact, but a concrete flat plate is placed on the outside of this top plate with backfill earth and sand interposed, and this concrete flat plate holds the concrete box in place. The backfill earth and sand acts as a cushioning material and softens the impact.

Furthermore, even if a crack occurs in the top plate, there is no risk of the road surface collapsing as the road surface is supported by the concrete flat plate, and any damage to the top plate can be repaired from inside the concrete box without blocking traffic on the road surface. It is possible to do so.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment of the protective structure for a concrete underground structure of the present invention, and 4 in the figure is an underground structure formed by vertically arranging the concrete boxes 1 shown in FIG. 6. .

The concrete box 1 is made of reinforced concrete, PC
(Prestressed) concrete and various other types of concrete can be used.

This underground structure 4 is buried under the road surface to form an underground passage, etc., but backfill soil 5 is provided on the top plate la of the concrete box l, and the top surface is covered with road surface such as asphalt. Paving 6 is applied.

7 in the figure is crushed stone as a road foundation.

In the present invention, a concrete flat plate 8 is buried between the top plate 1a of the concrete box 1 and the road pavement 6 in parallel to the top plate 1a.

This concrete flat plate 8 is also made of reinforced concrete,
Various types of concrete such as PC concrete and fiber concrete can be used.

There is no particular limitation on the depth to which this concrete flat plate 8 is buried, but if it is placed close to the road pavement 6, the crushed stone 7 as a road foundation may be omitted.

In addition, the width of the concrete flat plate 8 is the width of the concrete box 1.
The width of the concrete plate 8 may be the same as or slightly larger than the width of the upper surface plate 1a.Furthermore, this concrete flat plate 8 has a large number of panels connected in a vertical line, and each panel is provided with a small through hole passing through each other in the length direction. A tension material such as a copper rod or a PC steel wire is inserted here and fixed under tension.

Next, a method for constructing a protective structure for a concrete underground structure according to the present invention will be explained.

Figures 2 to 5 are vertical side views showing each process, and 9 in the figure is an open shield machine, which is a U-shaped shield machine with open front and top surfaces consisting of left and right side wall plates and a bottom plate connecting them. It is.

The open shield machine 9 has a cutting edge 10 formed at the tips of the side walls and the bottom plate, and propulsion jacks 11 are disposed in the center or near the rear end of the side wall plates, arranged rearward and vertically.

This shield machine 9 is installed in the starting shaft 12, and earth and sand in front of the starting shaft 12 is excavated and discharged from the front or top opening of the shield machine 9. Then, the propulsion jack 11 of the shield machine 9 is extended to take a reaction force from the reaction wall 13 in the launch shaft 12 to move the shield machine 9 forward, and the first concrete box body is moved to the tail part of the shield machine 9. It is suspended from above and placed behind the retracted propulsion jack 11.

Next, earth and sand are similarly excavated and discharged from the front or upper surface of the shield machine 9, and the shield machine 9 is moved forward.
A second concrete box l is suspended in front of the second concrete box l.

Thereafter, the same excavation and setting process of the concrete boxes 1 is repeated to sequentially bury the concrete boxes 1 vertically in the ground, and as shown in FIG. Inject grout with pump 14,
Further, backfilling soil 15 is applied on top of the concrete box 1.

When laying such backfill earth and sand 15, as described above (a concrete flat plate 8 is buried parallel to the top plate 1a of the concrete box 1).

Then, as shown in FIG. 4, road surface paving 6 is applied to the upper surface of the backfilling earth and sand 15 using a tire roller 16 or the like.

In this way, as shown in FIG. 5, when the open shield machine 9 reaches the reaching shaft 17, it is removed and the construction is completed.

(Effects of the Invention) As described above, the protective structure for concrete underground structures and its construction method of the present invention can prevent the top plate of the concrete box from being damaged by impact such as explosion from inside. A concrete flat plate is placed on the outside with backfill earth and sand interposed between them, and the backfill earth and sand pressed down by this concrete plate acts as a material to soften the impact.

Furthermore, even if a crack occurs in the top plate, there is no risk of the road surface collapsing as the road surface is supported by the concrete flat plate, and any damage to the top plate can be repaired from inside the concrete box without blocking traffic on the road surface. It is possible to do so.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the protection structure for concrete underground structures of the present invention, Figs. The figure is a perspective view of an underground structure made of concrete. 1... Concrete box 1a... Top plate 1b... Left side plate 1c.
...Right side plate 1d...Bottom plate 2...Corner part
3.--Hollow penetration part 4...Underground structure 6--Road surface pavement placement...Concrete flat plate 10...Blade opening 12...Starting hole 14...Gout pump 16...Tire roller

Claims (2)

[Claims] (1) Protection of concrete underground structures characterized by burying a concrete flat plate between the top plate of the concrete boxes and the road surface pavement when the underground structures are constructed by connecting concrete boxes in tandem underground. structure. (2) A propulsion jack is installed inside the shield machine with the top and front sides open, excavation is made from the front or top of the front part of the shield machine, and the propulsion jack is used to advance the shield machine using the existing underground structure of the following concrete box as a reaction force. Then, as the shield machine moves forward, a new concrete box is lowered from the upper surface of the rear of the shield machine and placed in the front row of the existing underground structure. In the open shield construction method, in which the top surface of a medium structure is appropriately backfilled and road surface pavement is applied to the top surface, when performing this backfilling, concrete flat plates are placed in tandem between the top surface plate of the concrete box and the road surface pavement, and lined up with the top surface plate. A method of constructing a protective structure for a concrete underground structure, which is characterized by being buried in a concrete underground structure.