JPS63184693A - Method of protection construction of existing tunnel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention provides a method for reinforcing underground tunnels from the outside without hindering the use of the tunnels, for example, as underground tunnels in urban areas become obsolete. Regarding protection construction methods for existing tunnels.

(Prior art) As underground tunnels become older, the simplest construction method to use them as they are without destroying them and to carry out tunnel reinforcement work is as shown in Figure 7. , both sides N+ 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 plate 3 is erected, and the existing tunnel 1 is surrounded.

(Problem 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 part 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 the case of aging subway tunnels in downtown areas, the facilities above 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. Yes, therefore,
Practically speaking, this type of construction method has a very limited range of application.

In addition, if the existing tunnel 1 is to be demolished and a new tunnel constructed instead of this type of protection work, an alternative site must be secured in advance to detour the commercial track, so there is not enough room for an alternative site. Without it, the moss construction work would not be possible.

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 a starting shaft on both sides of an existing tunnel, and using a tunnel construction method to extend the existing tunnel in a predetermined section using the starting shaft as a starting point. A pair of shafts are excavated along both sides of the tunnel, and then hollow boxes are successively arranged closely parallel to each other along at least the top of the existing I-channel from one side of each shaft to the other using the propulsion method. , characterized in that concrete is cast inside the shaft and the box part in a state where they communicate with each other, and both sides and the top of the existing tunnel are surrounded by concrete protective walls and a top slab. do.

(Function) 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 the starting shaft there, the A shaft can be excavated along both sides of the existing tunnel without being affected or interfered with by buried objects, and the completed state will be structurally exactly the same as when the existing tunnel was surrounded by an underground continuous wall and at least a top plate. Become.

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

FIGS. 1 to 6 show an embodiment of this 1ull.

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 1 are installed on both sides of the existing tunnel 10.
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 will be located in that part! ! Although it is sufficient to provide the shaft 12, 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, the shaft 1
From 2 to 2, guide shafts 14a and 1 are constructed using tunnel construction methods, respectively.
Existing tunnel 10 with 4b and 14c stacked in three stages
excavated along both sides of the

The guide shafts 148 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 manual method or a mechanical method using a rock bolt method. Ru.

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 steel sections are arranged at appropriate intervals along the excavation direction.

Since one side of each shaft 148 to 14G faces the side wall of the existing tunnel 10, the excavated wall surface is reinforced with sprayed concrete 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 to reduce the vertical bearing capacity of the protective wall and the lateral earth pressure. Reinforce horizontal support capacity.

Next, inside this tunnel 14a, a lower level protection is installed at a slight distance from the side of the existing tunnel 10, with a wall thickness determined by the cross-sectional force generated by the structural shape, load, etc. constructed by the propulsion method described later. The wall 19a is formed by installing a formwork along the shaft 14a, assembling reinforcing bars, and then pouring concrete.

Then, when the lower banishing wall 19a is constructed, the formwork is removed and aerated concrete or the like is filled between the first banishing wall 119a and the guide shaft 14a.

When filling is completed, the second stage shaft 14b is excavated,
After excavation, a middle protection wall 19b is constructed at the upper end of the lower 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. This shaft 14
The height of c protrudes from the top of the existing tunnel 10,
After completion of the guide shaft 14c, a hollow box is installed on the side surface of the upper protruding part, perpendicular to the upper longitudinal direction of the existing tunnel 10, from one guide shaft 14c to the other guide shaft 14C sandwiching the existing tunnel 10. 30 placement operations are performed.

Prior to propulsion of the hollow box 30, the guide shaft 1 on the starting side
A transport rail 24 for the hollow box 30 with a 20° transport rail for excavated earth and sand is laid in the inside 4c.

On the transport rail 24 is a trolley 2 for transporting the hollow box 30.
6, and a starting truck 27 that sets the hollow box 30 received from the truck 26 to the propulsion 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 guide rail 40 of the hoist crane 38 is fixed to
A hoist crane 44 is provided, which connects one end to the belt conveyor 42 and suspends the belt conveyor 42 located on the conveyor truck 34 at the lower end thereof. Furthermore, the cart 26 for the hollow box 30 is also connected to the battery cart 36 so that it can be moved by being towed by this.

After the above preparation work, the propulsion jack 22 was fixed at the most extreme position of the protected area in the starting side shaft 14C1, and by the pressing force of this propulsion jack 22, it was transferred to the propulsion truck 27 via the transport truck 26. A rectangular hollow box 30 with a cutting edge 30a at the tip is press-fitted orthogonally onto the top of the existing tunnel 10 while excavating the earth and sand inside it, and the excavated earth and sand is conveyed via a belt conveyor 42 to a transport vehicle. Discharge to the 34 side.

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 section are all rectangular steel pipes surrounded by side plates on all sides, and have the same structure as the conventional propulsion method.

Next, the hollow box for propelling the work section adjacent to this section 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. 5(a) to 5(d), this hollow box 50 has a top plate 50a and a bottom plate 50b made of steel plates similar to those described above, but has a U-shaped cross section with an open side. The side portion is made of a wire mesh plate 50c such as lath. In addition, the upper and lower sides of both sides are reinforced with angle plates 52, and the sides of each angle plate 52 are integrated with hook-shaped hook portions 54 that are oriented in opposite directions and protrude from the side. The bodies 50 are joined in a state in which they are engaged with each other in a piece-like manner, so that 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 the caulking material 56, the joint surfaces of the hollow boxes 50 are completely sealed, and a watertight state can be maintained. Further, since the connection is weak only by the engagement of the hook portions 54, if the angle plates 52 of the preceding and following hollow boxes 5o are connected with each other with bolts B each time one propulsion operation is completed, each hollow box 50 can be connected to each other as described above. It joins vertically and horizontally to form a strong bond.

The above promotion work will be carried out in exactly the same way as in the first section.

By repeating the same procedure and arranging the hollow boxes 50 throughout the protection work area, the subsequent work areas adjacent to each preceding work area will be joined in a vertical and horizontal matrix shape with horizontal communication through the wire mesh plate 50C, and will form a flat plate. One space is surrounded by each hollow box 50.

In addition, in the final section, a hollow box 3 similar to the first section is used.
0 group is used to perform the propulsion work and completely isolate the protected area from the non-protected area.

After the propulsion work was completed as described above and the 30°50 section of the hollow box was connected to the guide shaft 140.14G, each piece of equipment was removed and a tunnel was formed on the ceiling surface of the existing tunnel 10. WAN reinforcement is arranged vertically and horizontally inside the space, concrete is poured, and the top plate 62 is constructed.

Then, when the top plate 62 is constructed, the guide shaft 14C914C
After constructing an L-shaped upper protection wall 19c with reinforced concrete that connects the middle protection walls 19b, 19b formed inside the second stage guide shaft 14b and both ends of the top plate 62, the guide shaft 14c , 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 plate 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 they may be formed in one layer considering the height of the existing tunnel 10 and workability. However, there may be more.

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,
A hollow box 30.
50 to penetrate the other end. However, in this case, it is necessary to support the weight 1 of the existing 1 Hennel 10, and there are cases where it is not 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 1 of the existing 1 Hennel 10. It is sufficient to carry out the propulsion work in a divided state, and repeat the propulsion work for the next section after concrete is poured.

Furthermore, the hollow box 50 with an opening-shaped cross section shown in the above embodiment
The opening on one side may be made of a removable steel plate and 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 in each of the shafts 14a to 14C. It is also possible to use the entire cross-sectional area as the protective wall 60 by pouring it.

(Effects) As explained in detail using the embodiments above, in the existing tunnel protection 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, the construction method of this invention is particularly suitable for the protection and reinforcement work of dilapidated tunnels in urban areas, and can be performed at minimum construction cost.

[Brief explanation of the drawing]

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 5 (a) is A perspective view showing a hollow box used in the propulsion method, (b) is a cross-sectional view, (c) is a partial cross-sectional view showing the state in which the hollow boxes are connected to each other in phosphor work sections, and (d) is a partial cross-sectional view showing the state in which the hollow boxes are connected to each other. 6 is a front sectional view showing the completed state of the protection structure, and FIG. 7 is a front sectional view showing the case where an existing tunnel is protected by a general underground 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 6
0... Protective wall 62... Top plate (protective plate)

Claims (2)

[Claims] (1) A starting shaft is excavated on both sides of the existing tunnel, and a pair of guide shafts are excavated along both sides of the existing tunnel in a predetermined section using the tunnel method using the starting shaft as the starting point, and then each guide shaft is excavated using the propulsion method. hollow boxes along at least the top of the existing tunnel from one side to the other side are arranged in close parallel order, and the shaft and the box part are in communication with each other, and pour concrete,
A protection construction method for an existing tunnel characterized by surrounding both sides and the top of the existing tunnel with concrete protective walls and a top slab. (2) The method for protecting an existing tunnel according to claim 1, characterized in that reinforcing piles are sequentially constructed below each of the shafts by a cast-in-place pile method.