JPH0416598B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention is a method for reinforcing existing tunnels from the outside without interfering with the use of the tunnels, as underground tunnels in urban areas become obsolete. Concerning protective construction methods.

《Prior art》 As underground tunnels become obsolete, the easiest way to use them as they are without destroying them and to carry out tunnel reinforcement work is as shown in Figure 7. , Both sides of the existing tunnel 1 are surrounded by underground continuous walls 2, and in this state, the upper part of the existing tunnel 1 is excavated, a concrete top slab 3 is erected, and the existing tunnel 1 is surrounded.

<<Problems to be solved by the invention>> However, in order to carry out this construction in urban areas, etc., it is necessary to consider the relationship between the above-ground parts and existing buildings, the gas pipes placed underground above the existing tunnel 1, etc. Various underground structures such as water and sewage pipes and telephone cable pipes must be considered. 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. Therefore, the range of application of this type of construction method is actually very limited.

In addition, in place of this type of protection work, the existing tunnel 1
Even if a new tunnel is to be built by demolishing a new tunnel, it is necessary to secure an alternative site in advance to detour the commercial track, so if there is no available alternative site, the rebuilding work will not be able to proceed. was.

This invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a protective structure almost equivalent to that shown in FIG. 7 in the finished state without destroying the existing tunnel.

<<Means for Solving the Problems>> In order to achieve the above object, the present invention involves excavating starting shafts on both sides of an existing tunnel, and starting from the starting shafts and using a tunnel construction method to create a pair of starting shafts along both sides of the existing tunnel. A shaft is excavated, and then a plurality of hollow boxes are successively pressed into one section of each shaft from one side to the other along at least the top of the existing tunnel using the propulsion method and arranged closely in parallel. A matrix-like box section was formed by sequentially press-fitting the boxes into the preceding section and the subsequent section adjacent to the subsequent section and arranging them closely in parallel, and reinforcing bars were arranged inside the shaft and the box section. This is a protection method for an existing tunnel in which concrete is poured afterward and both sides and the top of the existing tunnel are surrounded by concrete protection walls or a top plate, and the box has openings in the front and rear side walls in the press-fitting direction. In addition, by having an opening in one of the left and right side walls and providing a mesh plate in the other side wall, the boxes in the same construction section and in adjacent construction sections are interconnected, and the above-mentioned It is characterized by integrating the top slab that surrounds the top of the existing tunnel.

《Operation》 If you select a small area of land that is closest to the section to be protected and will not be affected by existing buildings or buried objects, and excavate a starting shaft there, the existing buried objects above the tunnel will be removed. The shaft can be excavated along both sides of the existing tunnel without being affected or interfered with by the tunnel, and the completed state will be structurally exactly the same as if the existing tunnel were surrounded by an underground continuous wall and at least a top slab.

Moreover, the hollow box that forms the matrix-like box portion by press-fitting the box has openings 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 mesh plate on the other side wall, boxes in the same section and in adjacent sections are communicated with each other, so if concrete is poured inside the box, it will be possible to enclose the top of the existing tunnel. An integrated top plate can be obtained.

<<Example>> Hereinafter, an example of the present invention will be described in detail using the drawings.

1 to 6 show an embodiment of the present invention.

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 of the outer periphery of this existing tunnel 10 is protected is explained.

First, a pair of starting shafts 12 are excavated on both sides of the existing tunnel 10. The starting shaft 12 is located on the side of the subway track within the existing tunnel 10.
If there is room to excavate the starting shaft 12
However, the starting shaft 12 does not necessarily need to be provided in the existing tunnel 10, and if there is a place on the ground where it can be excavated, it can be selected 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 for excavation work according to the height of the existing tunnel 10, and as the excavation method, a manual method or a mechanical method using a lock bolt construction method is adopted. .

In this embodiment, the cross-sectional shape of each of the guide 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 method, thereby increasing the vertical bearing capacity of the protective wall and the side soil. Reinforce horizontal support against pressure. Next, inside this shaft 14a, a wall thickness determined by the cross-sectional force generated by the structural shape and load etc. constructed by the propulsion method described later is installed at a slight distance from the side of the existing tunnel 10. The lower protective wall 19a is formed by installing a formwork along the shaft 14a, 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 at the upper end 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 placed toward the other shaft 14c by a propulsion 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.

Arranged on the transport rail 24 is a truck 26 for transporting the hollow box 30, and a starting truck 27 for setting the hollow box 30 received from the truck 26 into a propelling position.

A cart 32 for installing the propulsion jack 22 is arranged on the excavated earth and sand transportation rail 20, connected to the frontmost part of the excavated earth and sand transport truck 34, and pulled by a battery locomotive 36. Further, a guide rail 40 of a hoist crane 38 is fixed to the ceiling surface of the guide shaft 14c, and the hoist crane 38 is connected to the trolley 32 at one end and suspends a belt conveyor 42 located on the transport trolley 34 at the other end. Set it up. Furthermore, a trolley 2 for the hollow box 30 is provided.
6 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,
The rectangular hollow box 30, which has been transferred to the starting cart 27 via the transport cart 26 and has a cutting edge 30a at its tip, is press-fitted orthogonally onto the top of the existing tunnel 10 while excavating the earth and sand inside. The soil is discharged to the transport vehicle 34 side via the belt conveyor 42.

After the first hollow box 30 is press-fitted, the rear end of the hollow box 30 is joined with a steel collar, and the next hollow box 30 is added, press-fitted using the propulsion jack 22, and earth and sand excavated manually. 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 propelling the work area adjacent to this work area is the same as the first one with a cutting edge 30a attached, but the hollow box itself has a special shape.

That is, as shown in FIGS. 5a to 5d, the top plate 50a and bottom plate 50b of this hollow box 50 are 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 are The side walls have an open U-shaped cross section, 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 hook parts 54 in opposite directions are integrated into the sides of each angle plate 52 and protrude from the sides, so that each hollow in the adjacent work section is The boxes 50 are joined together in a hook-shaped engagement state, and the hollow boxes 50 in adjacent construction areas 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. Furthermore, since the connection is weak only by engaging the hook portions 54, 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 They connect vertically and horizontally, creating a strong bond.

The above-mentioned propulsion work is performed in exactly the same way as in the first section, and if the same procedure is repeated sequentially along the length direction of each shaft 14c and the hollow boxes 50 are placed throughout the protection section, the same Box 5 in the construction area
0 and 50 communicate with each other through openings in the front and rear directions, and the succeeding sections adjacent to each preceding section communicate with each other laterally through the wire mesh plate 50c and the openings, thereby forming boxes closely arranged in a vertical and horizontal matrix. The insides of the bodies 50, 50, ... (box parts) can be integrally communicated in the front, rear, left and right directions, and as will be described later, the insides of the bodies 5
The top slab 62 formed by pouring concrete within the spaces 0, 50, . . . can be integrated into a flat plate shape, and the top slab 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.

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. The top slab 62 is constructed by arranging reinforcing bars vertically and horizontally inside the body and pouring concrete.

Then, when the top plate 62 is constructed, the shaft 14
L-shaped upper protection wall 19 connecting middle protection walls 19b, 19b formed in second-stage guide shafts 14b, 14b and both ends of top plate 62;
After building c with reinforced concrete, the guide shaft 14
The voids in spaces c and 14c are filled with aerated concrete, and 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, the guide shafts 12a to 12c formed on both sides of the existing tunnel 10 are formed in a three-tier stacked state, but considering the height of the existing tunnel 10 and workability, it may be one-tier. However, it may be more than that.

Further, in this embodiment, the protective 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 hollow boxes 30, 50 are pushed into the side of the lowermost shaft by the thrusting method,
Pass it through to the other end. 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 sufficient to carry out the propulsion work in this state, and repeat the propulsion work for the next section after concrete is poured.

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

Furthermore, the other wire mesh plate 50c may be a perforated plate with holes drilled at appropriate locations, and the protective wall 60 may be made of concrete by placing reinforcement inside each of the shafts 14a to 14c. It is also possible to cast the entire cross-sectional area of the protective wall 60.

<<Effects>> As explained in detail using the embodiments above, in the existing tunnel protection construction method of the present invention, at least the part exposed to the ground surface is only the pair of starting shafts, and most of the other parts are exposed to the ground surface. Since the work part is underground, the ground surface area required for construction can be kept to a minimum, allowing work to proceed without interference from underground objects above the existing tunnel or the foundations of existing buildings. can.

Therefore, this invention construction method is particularly suitable for the protection and reinforcement work of dilapidated tunnels in urban areas, and can be performed at minimum construction cost.

Moreover, by arranging the boxes in close contact with each other, hollow boxes in the same construction section and adjacent construction sections can communicate with each other. By pouring concrete into the top plate, the top plate can be integrated into a flat plate, and a high-strength top plate 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. 10...Existing tunnel, 12...Starting shaft, 14a
~c... Guide shaft, 18... Reinforcement pile, 28... Propulsion jack, 30... Hollow box, 50... Hollow box, 50c...
Wire mesh plate (mesh plate), 60...protective wall, 62...top plate.

Claims (1)

[Claims] 1. Starting shafts are excavated on both sides of an existing tunnel,
Starting from the starting shaft, a pair of shafts are excavated along both sides of the existing tunnel using the tunnel method, and then a pair of shafts are excavated along both sides of the existing tunnel using the propulsion method, from one section of each shaft to the other, along at least the top of the existing tunnel. After sequentially press-fitting multiple hollow boxes and arranging them closely in parallel, a matrix-shaped box section is formed by sequentially press-fitting the boxes into the preceding construction section and the following construction section and arranging them in close parallel. A protection method for an existing tunnel, in which concrete is poured inside the shaft and the box, and both sides and the top of the existing tunnel are surrounded by concrete protective walls or a top slab, the method comprising: The body has an opening on the front and rear side walls in the press-fitting direction, has an opening on one of the left and right side walls, and has a mesh plate on the other side wall, so that it can be used within the same construction area or in adjacent construction areas. A method for protecting an existing tunnel, characterized in that the boxes are connected to each other and a top plate surrounding the top of the existing tunnel is integrated. 2. The method for protecting an existing tunnel according to claim 1, characterized in that reinforcing piles are sequentially constructed below each shaft by a cast-in-place pile method.