JP2514514B2 - How to build an underground cavity - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a large-scale hemispherical or dome-shaped underground cavity having a diameter of several tens to 100 m, such as an underground power plant or an underground tank for oil storage, in bedrock. It is a thing.

[0002]

2. Description of the Related Art Conventionally, as a method of constructing such a large-scale underground cavern in rock, first, a portion corresponding to the upper end of the planned underground cavern is excavated in the rock, and then the excavated wall surface is excavated. A construction method is used in which concrete lining is applied, and then the rock cutting in the planned underground cavity is dug down by the bench cut method at appropriate depths, and concrete lining is applied to the excavated wall surface in order.

[0003]

However, according to such a method, concrete lining is sequentially performed each time a wide rock area having a suitable height in the planned underground cavity is excavated. Since the rock excavation work requires a great deal of work and cannot be moved to the next lining work unless the work is completed, the work efficiency is poor and the construction period becomes extremely long.

Further, when excavating by bench cut, the rock is destroyed by blasting, but the vibration at the time of blasting is transmitted to the concrete lining under construction and the lining is cracked. There were problems such as vibration pollution in the surrounding area. An object of the present invention is to provide a novel method for constructing a new underground cavity that can completely eliminate such problems.

[0005]

In order to achieve the above object, the method of constructing an underground cavity of the present invention is to excavate a closed annular tunnel along the lower end of the contour line of a planned underground cavity to be formed in bedrock. After that, create a space on the inner side of this tunnel
While still remaining , concrete is poured into the tunnel to form a lining, and then a closed annular tunnel is excavated on the upper side of the lining along the contour line of the planned underground cavity in the same manner as the closed annular tunnel . Along with the inner space of the lining
Is filled with shock absorbing material such as excavated shear or foam mortar
Then , a continuous lining is formed on the lining by placing concrete in the tunnel while leaving a space on the inner circumference side of the tunnel, and this work is performed in the planned underground cavity. By excavating repeatedly in the upward direction along the contour line, excavated shear or foamed mortar in the space on the inner peripheral surface side.
It is characterized by forming a lining of a planned underground cavity that is filled with a cushioning material such as a bridge, and then excavating the internal rock surrounded by this cushioning material using a blasting method. To do.

[0006]

[Operation] The concrete lining is applied to the inside of the closed underground tunnel having a predetermined height and width along the contour line of the planned underground cavity while excavating the closed annular tunnel in sequence. The entire lining of the planned underground cavern is formed without excavating the internal rock mass of the cavern. Then, the rock surrounded by this lining is continuously excavated and removed by a bench-cut method or the like to form an underground cavity. At this time, at the time of forming the lining, a space portion is provided on the inner surface side of the lining, and the space portion is filled with a cushioning material such as excavated shear or foam mortar to cover the inner surface of the lining.
Since the lining is formed, the blasting method is used to form the internal rock mass.
When excavating, it is possible to prevent vibration etc. at the time of blast from directly acting on the lining by the cushioning material , and
It does not cause vibration pollution in the surrounding area.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.
In constructing a large-section underground cavern such as an oil storage tank at a desired location of bedrock A, first, as shown in FIG. 1, after excavating an access tunnel 1 reaching the lower end of the planned underground cavern B, A closed annular tunnel 2a having a rectangular cross section of 3 to 4 m square is excavated from the access tunnel 1 along the lower end of the contour line of the planned underground cavity B while being horizontally bent at a predetermined curvature. The closed annular tunnel 2a is not limited to a circular shape as shown in the figure, but may be a rectangular shape or any other suitable shape.

Further, as the excavation means, an appropriate slot excavator is used, and as shown in FIG. 2, a slot having an appropriate depth in the tunnel length direction along the outer periphery of the tunnel cross-sectional shape is formed on the rock surface. 11 is continuously formed and the rock surface surrounded by the outer peripheral groove hole 11 is also divided by vertical and horizontal groove holes 12 and 13, and a blast hole 14 is formed in the rock portion surrounded by these groove holes 11 to 13. Then, it is loaded with explosives and blown up to excavate.
Moreover, an appropriate rock excavator can be adopted as needed. The excavated rock is discharged to the outside using the access tunnel 1.

Thus, the closed annular tunnel 2a as described above is formed by sequentially excavating a tunnel portion of an appropriate length along the lower end of the contour line of the planned underground cavity B and connecting them in series. While following or after excavation of this closed annular tunnel 2a, the tunnel 2
Assembling the mold in a, as shown in FIG. 3, after arranging the reinforcing bars 15, concrete is placed to form a concrete lining 3a. At this time, the formwork is assembled so that the space portion 4 is continuously left in the tunnel inner circumferential portion in the tunnel length direction, and concrete is poured into the tunnel 2a other than the space portion 4 to lining the lining 3a. To form.

On the other hand, as shown in FIG. 5, the working tunnel 5 is excavated in an upward spiral shape in communication with the access tunnel 1 along the inner peripheral side of the contour line of the planned underground cavity B, The upper end is provided up to the inner peripheral surface of the top of the planned underground cavity B, and the vertical shaft 6 is excavated in the vertical direction from the top.
The work tunnel 5 and the vertical shaft 6 may be separately performed before and after the construction of the concrete lining, but it is preferable to perform the work tunnel 5 in parallel with the concrete lining.

Then, after the concrete placed in the closed annular tunnel 2a provided at the lowermost end of the contour line of the planned underground cavity B has hardened, this concrete lining 3
As shown in FIGS. 3 and 4 so as to overlap with a, the next closed annular tunnel 2b along the contour line of the planned underground cavity B
Is continuously excavated from a part of the spiral inclined working tunnel 5 corresponding to the height position of the closed annular tunnel 2b.
At this time, the tunnel 2b may be excavated by the excavating means above the hardened portion without waiting for the concrete lining 3a to be entirely hardened.

The concrete lining 3a in which a part of the rock mass crushed during this excavation communicates therebelow
It falls into the space 4 on the inner peripheral side and is filled with the shear 7 to prevent damage to the concrete lining due to blasting during later rock crushing. In addition, this slide 7
Instead of filling the space 4 with the space 4, the space may be filled with a cushioning material such as foamed mortar. Next, the concrete lining 3b is formed in the tunnel 2b excavated in the closed ring shape in the same manner as described above, leaving the space 4 on the inner peripheral side thereof, and is integrated on the concrete lining 3a on the lower side.

In this way, the concrete linings 3a, 3b, 3c, ... Are sequentially formed in a stack at predetermined heights along the contour line of the planned underground cavity B to the top of the cavity.
As shown in FIG. 5, a dome-shaped lining C that forms the wall of the planned underground cavity B is formed. In addition, concrete lining 3
As described above, a, 3b, 3c, ... Excavated each lining formation tunnel using the spiral inclined work tunnel 5 located on the inner peripheral surface side at the height position thereof.
Since the space 4 in which the concrete lining is not constructed is formed in a, 2b, 2c, ..., the upper tunnel may be excavated using this space 4.

After the formation of the lining C of the planned underground cavity B, the rock around the shaft 6 excavated from the top of the lining C during the formation of the lining C or after the formation of the lining C is shown in FIG. A bench cut method that uses crushing by blasting is used to sequentially dig a specified depth. The work tunnel 5 and the shaft 6 are used to carry out the excavated skid and carry in the equipment. At the time of blasting, since the lining C and the bedrock D in the planned underground cavity B are edged by the shear 7 or foam mortar filling the space 4 as described above, the blasting vibration is caused by the shear 7. It can be prevented from being absorbed and blocked by the foamed mortar and transferred to the lining C by being blocked.

Thus, by excavating and removing the bedrock D of the planned underground cavity B surrounded by the lining C to the position of the concrete lining 3a at the bottom, an underground cavity as shown in FIG. 7 is constructed and constructed. Thereafter, if necessary, a floor wall connected to the concrete lining 3a may be formed on the bottom surface by pouring concrete.

[0016]

As described above, according to the method for constructing an underground cavern of the present invention, a tunnel having a cross-sectional shape having a constant height from the lower end to the top along the contour line of the planned underground cavern, and Since a closed ring-shaped lining made by placing concrete in the tunnel is to be formed in a stacked state, the dome-shaped lining that will become the wall of the planned underground cavern without first excavating the bedrock in the planned underground cavern. Can be efficiently constructed, and then the rock bed surrounded by this dome-shaped lining is to be excavated, so a large volume of rock bed can be continuously excavated, and work efficiency is significantly improved. However, the construction period can be shortened.

Furthermore, since the rock excavation and crushing work is performed from the top to the bottom in the lining, there is no risk of rock collapse, safe work is possible, and the rock around the cavity is not relaxed. Therefore, it becomes possible to construct a pillarless underground cavity with a large cross section. Also, provide a space on the inner peripheral surface side of each concrete lining that is sequentially stacked.
The inner surface of the lining is covered by filling a cushioning material such as excavated shear or foam mortar into this space ,
After completion, excavate while crushing the internal rock mass using the blasting method
The vibration generated during cutting is hardly transmitted to the lining side, damage to the lining can be prevented, a strong underground cavity can be built, and vibration pollution is not given to the surrounding area.

[Brief description of drawings]

[Figure 1] Simplified perspective view of the planned underground cavity,

FIG. 2 is a front view of a tunnel face for explaining the tunnel excavating means,

FIG. 3 is a cross-sectional view of a state where a concrete lining is formed in the lowermost tunnel,

FIG. 4 is a cross-sectional view showing a state in which concrete lining is sequentially formed upward,

FIG. 5 is a simplified sectional view showing a state in which a vertical shaft and a spiral inclined work tunnel are provided,

FIG. 6 is a simplified cross-sectional view showing a rock excavation state in a lining,

FIG. 7 is a sectional view of an underground cavity.

[Explanation of symbols]

 2a Closed annular tunnel 2b Closed annular tunnel 3a Concrete lining 3b Concrete lining 4 Space part 5 Spiral inclined work tunnel 6 Vertical shaft 7 Buffer material A Rock B Planned underground cavity C Lining D Rock

Claims (1)

(57) [Claims] 1. After excavating a closed annular tunnel along the lower end of the contour line of a planned underground cavity to be formed in rock,
While leaving a space on the inner peripheral side of this tunnel , concrete is placed in the tunnel to form a lining, and then
In the same way as the closed loop tunnel above the lining, a closed loop tunnel was excavated along the contour line of the planned underground cavity.
In addition to excavating or foaming in the inner space of the lining
After filling the buffer material such as mortar,
A continuous lining is formed on the lining by placing concrete in the tunnel while leaving a space on the peripheral side, and this work is performed sequentially upward along the contour line of the planned underground cavity. By repeating the construction ,
Fill the space with a cushioning material such as excavated shear or foam mortar.
The plan is to form a lining for the underground cavern, and after this,
A method for constructing an underground cavity characterized by excavating an internal rock bed surrounded by a cushioning material using a blasting method .