JP2810970B2 - Underground facility frame structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a structure where underground water leakage is a problem, such as an underground structure such as an underground room or a tunnel, or a time capsule or a radioactive waste storage facility. The present invention relates to a skeleton structure of an underground facility applied to a structure or the like that needs to suppress water leakage during a long burial period.

[Conventional technology]

The concrete material itself has a water permeability of 1 × 10 ^-11 c
Although it is very difficult to permeate water at m / s or less, it was impossible to secure a water permeability of 1 × 10 ^-11 cm / s as a frame. For this reason, complete water stopping performance cannot be expected with concrete walls that constitute conventional underground structures and other structures. It is for the following reasons.

In general, when constructing a concrete wall such as an underground structure or a building, if the scale becomes large, concrete can not be cast at once due to construction technology. For this reason, there are several times in the case of underground structures such as basements and tunnels where underground water leakage is a problem, or concrete walls that constitute structures where rainwater or other water leakage is a problem such as general buildings. Water is likely to occur along the joint surface of concrete that was divided into two parts.

Therefore, as a general countermeasure against such inundation, a construction method is adopted in which a water-stop plate made of a water-blocking material such as rubber is arranged at a place crossing the joint surface to block the joint surface.

[Problems to be solved by the invention]

However, in the case of a skeleton that is required to guarantee long-term durability, even if the above-described water-blocking plate is arranged, the durability remains uneasy.

In addition, considering the cause of impairing the water stopping performance as a building body, concrete may have cracks due to shrinkage during hardening or structural cracks due to external force. Therefore, water infiltration along the cracked surface is likely to occur.

It is desirable that the underground structure is a structure with high durability for as long as possible.However, since earth pressure is applied to the underground facilities, tensile stress is applied to the concrete of the skeleton wall under the earth pressure. It required reinforcement with steel bars or steel frames to occur. For this reason, there was a drawback that the construction cost was higher than concrete which does not require reinforcement by steel bars or steel frames.

In addition, the concrete that composes the skeleton wall of the underground facility requires reinforcement with steel bars and steel frames. Sexual performance has the disadvantage that it cannot be expected for too long.

The present invention is intended to solve the above-described problems, and by preventing the permeation crack surface generated stochastically or the opening width of the joint surface unavoidable in construction technology from increasing, the permeation path. It is an object of the present invention to reduce the water permeability of the cracked surface and the joint surface, and to improve the water stoppage of the skeleton wall as a result.

Another object of the present invention is to make it possible to reduce the amount of use of reinforcing bars and steel frames or to adopt concrete walls that do not use reinforcing bars or steel frames at the frame walls of underground structures that had to be reinforced by reinforcing bars or steel frames. is there.

Still another object of the present invention is to eliminate a factor of deterioration of durability such as neutralization of concrete and corrosion of reinforcing bars by using a concrete structure that does not require reinforcement by steel bars or steel frames.

[Means for solving the problem]

For this purpose, the frame structure of the underground facility of the present invention has a space excavated in the ground, a shell structure constructed in the space, and a gap between the outside of the frame and the ground in a shell shape. And an expandable material to be constructed. Also,
The shell structure is an axially symmetric shell structure, and a material that expands by a reaction with groundwater is used as the expandable material.

[Action]

In the skeleton structure of the underground facility of the present invention, a compressive stress can be generated in the entire area of the skeleton by the expansion pressure of the expandable material and the reaction force of the ground. In addition, with an axisymmetric shell structure,
Since a material that expands by reaction with groundwater is used as the expansive material, an inflation pressure can be applied to the entire outer peripheral surface of the concrete skeleton wall and the entire inner surface of the ground.

〔Example〕

 Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a view showing one embodiment of a skeleton structure of an underground facility according to the present invention, wherein 1 is ground, 2 is a concrete skeleton wall,
Reference numeral 3 denotes an inflatable material, 4 denotes a joint surface, and 5 denotes a crack.

When the ground is solid rock such as granite, a tunnel having an elliptical cross section or a spheroidal (rugby ball type) cavity as shown in FIG. 1 can provide a stable space by providing a relatively small support structure. Can be maintained.

Accordingly, the present invention constructs a concrete structure wall 2 having a shell structure as shown in the figure, for example, a spheroid, a sphere, or a cylindrical body having an elliptical or circular cross section. The concrete skeleton wall 2 has structural mechanical characteristics unique to the shell structure. The gap between the outside of the concrete frame 2 and the ground (the rock wall surface of the underground cavity) 1 is filled with the expansive material 3. Here, the inflation pressure of the intumescent material 3 depends on the entire outer periphery of the concrete skeleton wall 2 and the ground 1
Works on the entire inner surface of the ground, and the expansion pressure acting on the ground 1
The expansion force acts on the entire outer periphery of the concrete skeleton wall 2 receiving the reaction force. As a result, a compressive force is gradually generated in the shell structure of the concrete skeleton wall 2 as the expansion proceeds.

As the expansive material 3 described above, expansive concrete or a clay material such as bentonite which swells due to infiltration of groundwater, a swellable resin, or the like may be used.

With the above structure, the concrete skeleton wall 2
The cracked surface 5 generated at the time of construction or the gap between the concrete joining surfaces 4 generated at the time of construction is blocked by the gradually increasing compressive stress, so that it is closed rather than opened.

FIG. 2 is a view for explaining the relationship between the water permeability and the binding force of a material having a crack.

The hydraulic conductivity of the cracked surface becomes smaller as the binding force increases, as shown in FIG. 2 (a). This was measured on rocks with cracks as shown in FIG. 2 (b), and the permeability was measured from the flow rate measurement results, with the horizontal axis representing the effective restraining force and the vertical axis representing the permeability. However, due to this, the hydraulic conductivity is increased by 1 to 2 due to the increase of the binding force.
It can be seen that the digits also decrease. Therefore, it is clear that the permeability of the cracks in the concrete decreases as the binding force increases, as in the case of the rock.

By the way, it is known that the strength of concrete is strong against compressive force and weak against tensile force. Therefore, in a structure such as an underground facility where a compressive force acts due to earth pressure from the outside or a tensile force acts due to water pressure from the inside, it is necessary to share the tensile stress and have a certain strength It was necessary to use reinforced concrete or steel frame concrete. However, in the underground structure according to the embodiment of the present invention shown in FIG. 1, since a compressive stress is generated in every part of the concrete skeleton, a reinforcing bar sharing the tensile stress becomes unnecessary in principle.

This compressive force controls the inflation pressure of the intumescent material by its formulation, and can be designed as desired.
The design strength of the concrete material can also be controlled by adding the expansive material. In other words, the expansion pressure and strength can be freely designed by blending the expandable material.
It is possible to prevent the skeleton from being destroyed due to excessive stress.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, the shape of the shell structure that generates a compressive force can be designed in various shapes other than the shape shown in FIG. Further, the thickness of the concrete wall can be appropriately selected and designed.

It is thought that the rate of carbonation of underground concrete is slow, but at the moment there is only carbonation prediction data for aerial concrete, so we have to carry out prediction of durability of reinforced concrete by carbonation based on it . However, in the underground structure according to the present invention, since it is possible to design a structure that does not require reinforcing bars or steel frames for concrete in principle, the structural durability of the concrete frame and the long-term guarantee of impermeability are lower than those of ordinary reinforced concrete. Obviously, this is very advantageous.

〔The invention's effect〕

As apparent from the above description, according to the present invention, it is possible to prevent the opening width of the stably occurring permeable crack surface and the joint surface unavoidable due to construction technology from becoming large, and the The water permeability of the surface and the joint surface can be reduced, and as a result, the water stoppage of the skeleton wall can be improved.

Also, the present invention makes it possible to adopt a concrete wall that reduces the use of reinforcing bars or steel frames, or uses no reinforcing bars at all, for building frames of underground structures that previously required reinforcement by reinforcing bars or steel frames. Thus, a lower cost concrete wall can be provided.

Furthermore, since the present invention uses a concrete structure that does not require reinforcement with steel bars or steel frames, it can eliminate durability deterioration factors such as neutralization of concrete and corrosion of steel bars. The long-term guarantee of structural durability and poor water permeability can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a skeleton structure of an underground facility according to the present invention, and FIG. 2 is a view for explaining a relationship between a hydraulic conductivity of a material having a crack and a binding force. 1 ... ground, 2 ... concrete skeleton wall, 3 ... expansive material, 4 ... joint surface, 5 ... cracks.

Claims (3)

(57) [Claims] 1. A space which is excavated in the ground, a shell having a shell structure constructed in the space, and an inflatable material which is constructed in a shell shape in a gap between the outside of the body and the ground. The skeleton structure of underground facilities. 2. The underground facility frame structure according to claim 1, wherein the shell structure is an axisymmetric shell structure. 3. The underground facility frame structure according to claim 1, wherein a material that expands due to a reaction with groundwater is used as the expandable material.