JPH0416599B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to a construction method for constructing a concrete slab underground, and particularly relates to a construction method that enables construction of a concrete slab without excavating the upper ground of the construction area. .

[Conventional technology] For example, as underground concrete ages,
In order to use this tunnel as it is without destroying it, and to carry out tunnel reinforcement work, the simplest method is to surround both sides of the existing tunnel 1 with underground continuous walls 2, as shown in Figure 7. In this state, the upper part of the existing tunnel 1 is excavated to create a concrete top slab 3, and after surrounding the existing tunnel 1, the concrete top slab 3 is backfilled with earth and sand.

[Problems to be solved by the invention] However, with this construction method, the upper ground must be occupied for construction purposes during the construction period, and in order to carry out this construction in urban areas, it is necessary to It is necessary to take into account various underground objects such as gas pipes, water and sewage pipes, and telephone cable pipes that are placed underground above the existing tunnel 1. Particularly in subway tunnels, which are aging rapidly in downtown areas, the buried objects above them are arranged in a complicated manner, making it difficult to know where they are located, and in some cases, existing buildings are located on the ground surface above the tunnel. sell. Therefore, in practice, this type of construction method could only be used on land where the upper ground could be occupied for a certain period of time for construction purposes.

This invention has been made based on the above background, and it is an object of the present invention to enable the construction of concrete slabs only by underground work without excavating the upper ground of the construction area for concrete slabs.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention involves excavating a guide shaft along at least one side of an underground concrete slab construction area, and then using the guide shaft as a starting side. After sequentially press-fitting multiple hollow boxes into one section perpendicular to the length direction and arranging them closely in parallel,
By sequentially press-fitting the boxes into the preceding work area and the subsequent work area and arranging them closely in parallel, the inside of the construction work area is formed by a matrix-shaped box part, and reinforcing bars are installed inside this box part. A construction method for an underground concrete slab in which concrete is poured after reinforcing, wherein the box has an opening in the front and rear side walls in the press-fitting direction, and has an opening in one of the left and right side walls, and By providing a net-like plate on the other side wall, boxes in the same construction section and adjacent construction sections are communicated with each other, and the concrete slabs are integrated.

《Operation》 With the above construction method, if the necessary work area on the ground surface to excavate the shaft can be secured, then the underground concrete plate can be created by doing all the work underground.

In addition, by arranging reinforcing bars in a matrix-shaped box part formed by press-fitting a plurality of boxes and then pouring concrete, an integrated concrete slab can be obtained.

<<Example>> Hereinafter, an example in which the present invention is applied to a protection construction method for an existing tunnel will be described in detail with reference to FIGS. 1 to 6.

In the figure, reference numeral 10 indicates a dilapidated existing tunnel in an urban area, and in the embodiment, a case where a predetermined section on the outer periphery of this existing tunnel 10 is to be protected is illustrated.

The construction method shown in the figure is to install a pair of starting shafts 1 on both sides of the existing tunnel 10 before constructing the concrete slab.
Drill 2.

If there is room to excavate the starting shaft 12 on the side of the subway track within the existing tunnel 10, the starting shaft 12 may be provided in that part, but the starting shaft 12 is not necessarily provided within the existing tunnel 10. It is not necessary, if there is a place above ground where it is possible to excavate,
You can also choose there.

When each starting shaft 12 is constructed to a predetermined depth,
From the shaft 12, guide shafts 14a, 14b, and 14c are excavated along both sides of the existing tunnel 10 in a three-tier stacked state using the tunnel construction method.

The guide shafts 14a to 14c are set to a width and height that allows excavation work according to the height of the existing tunnel 10, and the excavation method is a hand digging method or a mechanical method using a lock bolt method. Ru.

In this embodiment, the cross-sectional shape of the shafts 14a to 14c is rectangular, and shoring structures 16 made of rectangular combinations of H-beams are arranged at appropriate intervals along the excavation direction.

Since one side of each shaft 14a to 14c faces the side wall of the existing tunnel 10, the excavated wall surface is reinforced with shotcrete at least on the upper part and the other side.

After excavating the lowermost guide shaft 14a, reinforcing piles 18 are constructed below the guide shaft 14a at appropriate intervals along the excavation direction using the cast-in-place pile construction method, thereby increasing the vertical bearing capacity of the protective wall and the lateral earth pressure. Reinforce the horizontal support capacity against.

Next, inside this shaft 14a, a lower protective wall 19a is installed at a slight distance from the side of the existing tunnel 10, and has a wall thickness that is approximately equivalent to the thickness of the top slab constructed by the propulsion method described later. Draw frame 14
It is formed by installing concrete along line a, assembling reinforcing bars, and then pouring concrete.

After the lower protective wall 19a is constructed, the formwork is removed and aerated concrete or the like is filled between the protective wall 19a and the guide shaft 14a.

When the filling is completed, the second-stage guide shaft 14b is excavated, and after the excavation, a middle-stage protection wall 19b is constructed on top of the lower-stage protection wall 19a, and filled with aerated concrete or the like in the same manner as described above.

Next, the uppermost shaft 14c is excavated. The height of this guide shaft 14c protrudes from the upper part of the existing tunnel 10, and after completion of the guide shaft 14c, the side surface of the upper protruding part is perpendicular to the upper longitudinal direction of the existing tunnel 10, and one side of the existing tunnel 10 is sandwiched between the two sides. Shaft 14c
From there, the hollow box 30 is press-fitted into the other guide shaft 14c by a thrusting method.

Prior to the propulsion of the hollow box 30, in one of the guide shafts 14c on the starting side, a transport rail 20 for excavated earth and sand,
A transport rail 24 for the hollow box 30 is laid. On the transport rail 24 is a cart 26 for transporting the hollow box 30, and a hollow box 30 received from the cart 26.
A starting trolley 27 is arranged to set the vehicle in the propulsion position.

A cart 32 for installing the propulsion jack 22 is arranged on the excavated earth and sand transport rail 20, connected to the front end of the earth and sand transport cart 34, and pulled by a battery locomotive 36. In addition, the guide shaft 14
A guide rail 40 of a hoist crane 38 is fixed to the ceiling surface of c, and a belt conveyor 4 is connected at one end to the trolley 32 and the other end is located on the transport trolley 34.
A hoist crane 38 for hoisting 2 is provided. Furthermore, a carriage 26 for transporting the hollow box 30
is also connected to the battery trolley 36 so that it can be moved by being towed by this.

After the above preparation work, the propulsion jack 22 is fixed at the most extreme position of the protected area in the starting side shaft 14c, and by the pressing force of this propulsion jack 22,
A rectangular hollow box 30 with a cutting edge 30a provided at the tip, which was transferred via the transport cart 26 to the starting cart 27, is press-fitted orthogonally onto the top plate of the existing tunnel 10 while excavating the earth and sand inside it. The excavated earth and sand is discharged to the transport vehicle 34 side via the belt conveyor 42.

After the press-fitting of the first hollow box 30 is completed, the rear end of this hollow box 30 is joined with a steel collar, and while the next hollow box 30 is added, the pushing jack 22 is used to press-fit and excavate earth and sand by inputting. repeat.

Through the above operations, the hollow box 30 at the leading end reaches the other guide shaft 14c. Thereafter, the cutting edge 30a of this hollow box 30 is removed, and it is transported to one of the guide shafts 14c and used repeatedly for the next propulsion operation.

The hollow boxes 30 used in the first construction section are rectangular steel pipes that are open at the front and back and surrounded by side plates on all sides, and have a structure similar to that of conventional propulsion construction methods.

Next, the hollow box for promoting the work section adjacent to this work section is the same as the previous one except that it has a cutting edge 30a, but the hollow box itself has a special shape.

That is, as shown in FIGS. 5a to 5d, the hollow box 50 has a top plate 50a and a bottom plate 50b made of steel plates similar to those described above, but the front and rear side walls in the press-fitting direction and one of the left and right side walls. It has a U-shaped cross section with openings, and the other of the left and right side walls is constituted by a wire mesh plate (mesh plate) 50c such as lath.
In addition, the upper and lower sides of both sides are reinforced with angle plates 52, and hook-shaped hooks 54 in opposite directions are integrated into the sides of each angle plate 52 and protrude from the sides, so that each hollow box in the adjacent work area can be The bodies 50 are joined together in a hook-shaped engagement, and the hollow boxes 50 in adjacent construction sections can be closely arranged in a connected state.

Note that by filling the inside of the engagement surface of the hook portion 54 with caulking material 56 after the propulsion work is completed,
The joint surfaces of each hollow box 50 are completely sealed, and a watertight state can be maintained. In addition, since the engagement is weak if only the hook portion 54 is engaged, if the angle plates 52 of the preceding and following hollow boxes 50 are connected with each other with bolts B each time one propulsion operation is completed, each hollow box 50 are connected vertically and horizontally, forming a strong connection.

The above-mentioned propulsion work using the hollow boxes 50 is performed in exactly the same way as in the first section, and the same procedure is repeated sequentially along the length direction of each shaft 14c, and the hollow boxes are installed in the entire protection section. If you place 50,
The boxes 50, 50 in the same construction section communicate with each other through the openings in the front and rear directions, and the subsequent construction sections adjacent to each preceding construction section communicate with each other in the horizontal direction through the wire mesh plate 50c and the openings, thereby forming a vertical and horizontal matrix. The insides of the boxes 50, 50, ... (box parts) that are closely arranged can be integrally communicated in the front, back, left, and right directions, and as will be described later, concrete is poured inside the boxes 50, 50, .... The top plate 62 can be integrated into a flat plate shape, and the top plate 62 with high strength can be obtained.

In the final construction section, the same group of hollow boxes 30 as in the first construction section are used for propulsion work to completely isolate the protected construction section from the non-protected area.

Therefore, in the state where the propulsion work is completed, a flat plate is formed with the top plate 50a as the top surface, the bottom plate 50b as the bottom surface, and the outer parts of the hollow box 30 at the leading edge and the rear end of the construction area as both inner walls. Each hollow box 50 fills one space.
Formed inside surrounded by.

After the propulsion work is completed as described above and the hollow boxes 30 and 50 are communicated with the guide shafts 14c and 14c, each piece of equipment is removed and the box formed on the upper part of the ceiling of the existing tunnel 10 is removed. By arranging reinforcing bars vertically and horizontally inside the body and pouring concrete, construction of the reinforced concrete top slab 62 is completed. after that,
After constructing an L-shaped upper protection wall 19c in the shaft 14c with reinforced concrete, which connects the middle protection wall 19b formed in the second stage shaft 14b and both ends of the top plate 62, the shaft is opened. Once the void in the tunnel 14c is filled with aerated concrete, both sides and the top of the existing tunnel 10 are surrounded by a protective wall 60 and a top slab 62 made of reinforced concrete, and the construction is completed.

In addition, in this embodiment, in order to construct protective walls on both sides of the existing tunnel 10, the guide shafts 12a to 12c are
Although they are formed in three stacked layers, they may be one layer or more depending on the height of the existing underground structure and workability.

Further, in this embodiment, the protective concrete top plate 62 is provided only on the top of the existing tunnel 10, but a protective plate may also be provided on the bottom side of the existing tunnel 10. In this case, the side surface of the lowermost guide shaft 14a is excavated by the propulsion method, and the other end is penetrated.

However, in this case, it is necessary to support the weight of the existing tunnel 10, and it may not be possible to make a wide area into one space as in the above embodiment, so in that case, it is necessary to support the weight of the existing tunnel 10. It is necessary to carry out the propulsion work in this state, and repeat the propulsion work for the next section after concrete is poured.

Further, one side opening of the hollow box 50 having a U-shaped cross section shown in the above embodiment may be made of a removable steel plate, and may be removed after the hollow box 50 is press-fitted.

Furthermore, instead of the other wire mesh plate 50c, it may be constructed with a perforated plate with holes drilled at appropriate locations, so that reinforcing bars can be arranged vertically and horizontally within the space, and can be integrated into one piece by pouring concrete. The opening should be wide enough to accommodate the concrete protective plate.

Furthermore, the present invention is generally applicable to cases where the upper ground cannot be occupied for construction of an underground concrete slab when constructing an aging underground structure such as the above-mentioned existing tunnel protection method. In addition, the guide shaft does not necessarily need to be formed on both sides of the construction section, but if it is formed along at least one side of the construction section, the guide shaft can be used as the starting side and a large number of hollow boxes can be directed toward that section. Can be press-fitted sideways.

<<Effects>> As explained in detail using the examples above, in the method of constructing an underground concrete slab of the present invention, construction can be carried out without excavating the ground surface, and most of the working parts are Because it is underground, the surface area required for construction can be kept to a minimum, allowing work to proceed without interference from underground objects near the ground surface or the foundations of existing buildings. .

Therefore, with this invented method, it is not possible to occupy the ground surface for construction as in urban areas, and moreover, underground concrete slabs can be created independently even in places where there are existing buried structures near the ground surface, and it is especially useful in urban areas. It can provide a useful construction method for underground redevelopment work or reinforcement and protection work for aging structures.

Moreover, by arranging reinforcing bars in a matrix-shaped box part formed by press-fitting a plurality of boxes and then pouring concrete, an integrated concrete slab with high strength can be obtained.

[Brief explanation of drawings]

Figure 1 is a plan sectional view showing this invention method, Figure 2 is a side sectional view, Figure 3 is a front sectional view, Figure 4 is a front sectional view showing the propulsion process, and Figure 5a is the propulsion method. A perspective view showing a hollow box used for
is a partial cross-sectional view showing the state in which the hollow boxes are connected between adjacent construction sections, d is a partial plan view of the same combined state, Figure 6 is a front cross-sectional view showing the completed state of the protective structure, and Figure 7 is a general underground view. FIG. 2 is a front cross-sectional view showing a case where an existing tunnel is protected by the continuous wall construction method. 14c... Guide shaft, 28... Propulsion jack, 30... Hollow box, 50... Hollow box, 50c... Wire mesh plate (mesh plate), 60... Protective wall, 62... Top plate (concrete plate).

Claims (1)

[Scope of Claims] 1. A shaft is excavated along at least one side of a construction section for an underground concrete slab, and then a plurality of hollow boxes are excavated in one section perpendicular to the length direction of the shaft, with the shaft as the starting side. After the bodies are successively press-fitted and arranged closely in parallel, the boxes are successively press-fitted into the preceding work area and the subsequent work area and arranged closely in parallel, thereby forming the construction area into a matrix-like box part. This is a method of constructing an underground concrete slab in which concrete is poured after arranging reinforcing bars inside the box, and the box has openings on the front and rear walls in the press-fitting direction, and has openings on the left and right side walls. By having an opening in one side wall and providing a mesh plate in the other side wall, the boxes in the same work area and in adjacent work areas are interconnected and the concrete slabs are integrated. A construction method for underground concrete slabs that is characterized by: