JPH0464623A - Body structure of underground facility - Google Patents

Abstract

PURPOSE:To improve water-stop ability by filling an expansive material which expands corresponding to the underground water, and which is constructed in a shell form, in the gap between a shell-formed body constructed in the space excavated in the ground, and the ground outside thereof. CONSTITUTION:A concrete body 2 of cylindrical body such as rotational ellipsoid or spherical body, is constructed in a cave, and an expansive material 3 is filled in the gap between the outside of the body wall 2 and a ground 1. The expansive pressure of the expansive material 3 is worked on the entire surface of the outer periphery of the concrete body wall 2 as well as on the entire surface of the inside of the ground 1. The expansive pressure worked on the ground 1 is worked on the entire surface of the outer periphery of the body wall 2 as well as on the ground 1, receiving the reaction of the ground 1, and the compressive force is gradually generated as the expansion is proceeded farther on the shell structure of the body wall 2. A clay material such as bentonite or an expansive resin is used for the expansive material 3. A cracked surface 5 or a gap that serves as a water pass of a concrete jointing surface 4 is pressed by the compressive reaction, and stop-water ability can thus be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to structures where underground water leakage is a problem, such as underground structures such as basements and tunnels, or to time capsules and radioactive waste storage facilities. This paper relates to the framework structure of underground facilities, which is applied to structures that need to suppress water leakage during long-term burial.

[Conventional technology]

The concrete material itself has a permeability coefficient of 1×10”c
Although it is a material that is extremely difficult to permeate water (less than m/s), it has been impossible to secure a water permeability of I x 10-” am/s as a frame.For this reason, conventional underground structures and other The concrete walls that make up the structure could not be expected to have complete water-stopping performance for the following reasons.

In general, when constructing concrete walls for underground structures, buildings, etc., when the scale becomes large, concrete pouring cannot be done in one go due to construction technology, so it is common to do it in several parts. Therefore, concrete walls that make up structures such as underground structures such as basements and tunnels where leakage of groundwater is a problem, or structures where water leakage such as rainwater is a problem such as general buildings, can be used several times. Conch IJ was divided into
- Water is likely to infiltrate along the joint surface of the concrete.

Therefore, as a general countermeasure against such flooding, a method of damming the joint surface is adopted by installing a water stop plate made of water-stopping material such as rubber at the location that crosses the joint surface. .

[Problem to be solved by the invention]

However, in the case of a building frame that is required to guarantee long-term durability, even if a water stop plate like the one described above is installed, durability remains unsatisfactory.

In addition, considering the causes of deterioration of the water-stopping performance of concrete as a building block, cracks may occur in concrete due to shrinkage during hardening or structural cracks may occur due to external forces. Therefore, water tends to infiltrate along the cracked surface.

In addition, it is desirable for underground structures to be highly durable for as long as possible, but since earth pressure acts on underground facilities, the concrete of the frame walls receives tensile stress due to the upper pressure. This required reinforcement with reinforcing bars or steel frames. For this reason, it has the disadvantage of being more expensive to construct than concrete, which does not require reinforcement with reinforcing bars or steel frames.

Furthermore, the concrete that makes up the framework walls of underground facilities requires reinforcement with reinforcing bars and steel frames, but there are factors that degrade durability such as concrete neutralization and corrosion of reinforcing bars, The drawback was that the durability performance could not be expected for a very long period of time.

The present invention solves the above-mentioned problems, and prevents water permeable cracks from occurring stochastically and the opening width of the pouring joint surface from increasing, which is unavoidable due to construction technology, and thereby prevents water permeable paths. The purpose of this is to reduce the water permeability of cracked surfaces and joint surfaces, resulting in improved water-stopping properties of the building frame wall.

Another object of the present invention is to enable the adoption of concrete walls that use less or no reinforcing bars or steel frames in the frame walls of underground structures that have hitherto required reinforcement with reinforcing bars or steel frames. .

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

[Failure to solve the problem]

For this purpose, the framework structure of the underground facility of the present invention includes a space excavated underground, a shell structure framework built in the space, and a shell-shaped structure in the gap between the outside of the framework and the ground. characterized in that it is constructed of an expandable material. Further, the shell structure is an axially symmetrical shell structure, and the expandable material is a material that expands upon reaction with groundwater.

[Effect]

In the framework structure of an underground facility according to the present invention, compressive stress can be generated throughout the framework by the expansion pressure of the expandable material and the reaction force of the ground. In addition, since it has an axially symmetrical shell structure and uses a material that expands by reaction with groundwater as the expandable material, expansion pressure can be applied to the entire outer periphery of the concrete frame wall and the entire inner surface of the ground.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the framework structure of an underground facility according to the present invention, where 1 is the ground, 2 is a concrete framework wall, and 3 is a diagram showing an embodiment of the framework structure of an underground facility according to the present invention.
4 indicates an expansible material, 4 indicates a pouring surface, and 5 indicates a crack.

When the ground is solid rock such as granite, a tunnel with an elliptical cross section or a cavity with a spheroid or rough pole shape as shown in Figure 1 can be made stable by providing a relatively light support structure. can be maintained.

Therefore, in the present invention, a concrete frame wall 2 having a shell structure as shown in the drawings, for example, a spheroid, a sphere, or a cylindrical body having an elliptical or circular cross section, is constructed in this cavity. This concrete frame wall 2 has structural mechanical characteristics unique to a shell structure.

Then, the gap between the outside of the concrete g body wall 2 and the ground (rock wall surface of the underground cavity) l is filled with an expandable material 3. Here, the expansion pressure of the expandable material 3 acts on the entire outer circumference of the concrete frame wall 2 and the entire inside of the ground 1, and the expansion pressure acting on the ground 1 is subject to the reaction force of the ground 1.
Expansion pressure acts on the entire outer periphery of the concrete frame wall 2. As a result, compressive force is gradually generated in the shell structure of the concrete IJ-to frame wall 2 as the expansion progresses.

As the expandable material 3 shown above, expandable concrete, a clay material such as bentonite that swells when underground water permeates, a swelling resin, etc. may be used.

By using the above structure, concrete frame wall 2
The cracked surface 5 that occurs during construction or the gap that becomes a water path in the concrete pouring surface 4 that occurs during construction is suppressed by the gradually increasing compressive stress, so it does not open but rather closes.

FIG. 2 is a diagram for explaining the relationship between the permeability coefficient and restraining force of a material having cracks.

The hydraulic conductivity of the cracked surface becomes smaller as the restraining force increases, as shown in FIG. 2(a). This is the same figure)
The hydraulic conductivity coefficient is measured from the flow rate measurement results, and the horizontal axis represents the effective restraining force and the vertical axis represents the hydraulic conductivity coefficient.From this, the hydraulic conductivity coefficient is It can be seen that as the restraint force increases, it decreases by one to two orders of magnitude. Therefore, it is clear that the hydraulic conductivity of cracks in conch IJ) also decreases as the restraining force increases, as in the case of rocks.

By the way, it is known that the strength of concrete is strong against compressive force and weak against tensile force. Therefore, in the case of structures such as underground facilities where compressive force acts due to earth pressure from the outside or tensile force acts due to water pressure from the inside, it is necessary to share the tensile stress and maintain a certain level of strength. necessitated the use of reinforced concrete or steel-framed concrete. However, in the underground structure according to the embodiment of the present invention shown in FIG. 1, compressive stress is generated in all parts of the concrete frame, so reinforcing bars that share tensile stress are not required in principle.

This compressive force can be designed as desired by controlling the expansion pressure of the expandable material by its composition, and the design strength of the concrete material can also be controlled by controlling the composition of the expandable material. In other words, since the expansion pressure and strength can be freely designed by mixing the expandable materials, it is possible to prevent the structure from breaking due to an excessive increase in stress.

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

Concrete underground is thought to have a slow carbonation rate, but at present we only have carbonation prediction data for concrete in the air, so we have no choice but to predict the durability of reinforced concrete through carbonation based on that data. . However, since the underground structure according to the present invention can be designed without the need for reinforcing bars or steel frames in concrete in principle, the long-term guarantee of the structural durability and impermeability of the concrete frame is better than that of ordinary reinforced concrete. It is obvious that it will be very advantageous.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the opening width of the pour joint surface is wide (to prevent water permeable cracks that occur stochastically and due to construction technology), and It is possible to reduce the water permeability of cracked surfaces and joint surfaces that serve as routes, and as a result, improve the water-stopping properties of the building frame wall.

Furthermore, for the frame walls of underground structures that have hitherto required reinforcement with reinforcing bars or steel frames, the present invention makes it possible to use concrete walls that reduce or do not use reinforcing bars or steel frames at all. Therefore, we can provide concrete walls at a lower price.

Furthermore, since the present invention uses concrete structures that do not require reinforcement with reinforcing bars or steel frames, it is possible to eliminate durability deterioration issues such as concrete neutralization and corrosion of reinforcing bars, and as a result, underground structures It can improve the structural durability and long-term guarantee of low water permeability.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the framework structure of an underground facility according to the present invention, and FIG. 2 is a diagram for explaining the relationship between the permeability coefficient and restraining force of a material having cracks. ■...Ground, 2...Concrete frame wall, 3...
Expandable material, 4... Pour joint surface, 5... Cracks. Figure 1 Applicant Sub-agent of Shimizu Corporation Patent attorney Ryukichi Abe (7 others) 10++
10 + 10 + 10 + + 10 now + call + 10 → samurai 11 11 10 + + 10 + + + + + + 10 + + 10 ÷ 10 + 10 + 10 + 10 + 10 + 10 + 10 ten + ten + ten - 15 scarcity

Claims (3)

[Claims] (1) Consisting of a space excavated underground, a shell-structured framework constructed within the space, and an expandable material constructed in a shell shape in the gap between the outside of the framework and the ground. The framework structure of an underground facility characterized by: (2) The framework structure of an underground facility according to claim 1, wherein the shell structure is an axially symmetrical shell structure. (3) The framework structure of an underground facility according to claim 1, characterized in that the expandable material is a material that expands upon reaction with groundwater.