JPH0143879B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a joint for a cylindrical underground structure constructed underground, and the cylindrical underground structure can be used for, for example, water pipes, It is used to house gas pipes, electric wires, etc.

(Prior art) When the cylindrical underground structure is made of concrete,
As a joint for connecting these cylindrical underground structures in series, a simple joint is used in which a joint material such as rubber or asphalt impregnated material is interposed in the joint gap to prevent earth and sand or groundwater from entering the cylindrical underground structure. It has been known.

However, in this joint, the joint material is constantly subjected to high earth pressure or underground water pressure, so there is a risk that it will separate from the joint gap or tear, and high sealing performance cannot be expected. In addition, if the joints of underground structures shift due to uneven ground subsidence, earthquakes, etc., the joint material may become detached, or if the joint material is embedded and fixed in the underground structure, the joint material may become loose. There is a problem in that a large amount of earth and sand and groundwater intrude into the underground structure, making subsequent restoration extremely difficult.

(Object of the invention) The present invention provides a first method for preventing the intrusion of earth and sand and groundwater when the ground is normal in a joint for a cylindrical underground structure.
Seal plate and the first in case of abnormality such as uneven ground subsidence.
The basic purpose is to provide a second seal plate that catches earth and sand or groundwater when the seal plate is cut, and to ensure sealing performance in such abnormal situations. Another important object of the present invention is to prevent the first sealing plate, which ensures sealing performance under normal conditions, from expanding and deforming inwardly of the underground structure and bulging out due to the influence of earth pressure or groundwater pressure. It is in. In other words, if the first seal plate continues to be stretched and deformed, damage due to the effects of earth and sand and groundwater will progress rapidly and there is a risk of it breaking.
In that case, there is a concern that the second seal plate, which is supposed to exhibit sealing performance in abnormal situations, will receive dirt and sand during normal times and deteriorate quickly, and may break due to the impact of ground movement in abnormal times. The present invention attempts to solve this problem.

(Structure of the Invention) The joint of the cylindrical underground structure of the present invention has first and second joints.
The main components are a seal plate, a pair of pressure plates, and a pair of holding plates.

Both sides of the first seal plate are brought into contact with the inner peripheral surface of the cylindrical underground structure across the joint gap. The pair of pressure plates are stacked on both sides of the first seal plate, respectively, with a gap provided at the seam clearance position. Second
The seal plate has a flexible portion in the center, and both sides of the flexible portion are stacked on the pressure plate. Further, the presser plates are stacked on both sides of the second seal plate. The both sides of the first seal plate, the pressure plate, the both sides of the second seal plate, and the press plate are fixed to the cylindrical underground structure in a stacked state. At least one of the pressure plates has an end protruding toward the play area,
This prevents the first seal plate from expanding and deforming and bulging into the cylindrical underground structure due to earth pressure or water pressure.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 shows cylindrical underground structures 1, 1 made of concrete. Both underground structures 1, 1 are arranged facing each other with a joint clearance 2, and are connected by a joint.

The concrete structure of the joint 3 is shown in FIGS. 2 and 3. The main components of this joint 3 include a first seal plate 4, a pair of pressure plates 5, 5, a second seal plate 6, a pair of presser plates 7, 7, and anchor bolts 8, 8. The underground structures 1, 1 have cutout steps 9, 9 formed at the inner peripheral end of the joint, and anchors embedded in the underground structures 1, 1 are formed in the cutout steps 9, 9. Bolts 8, 8 are protruding.

The first seal plate 4 and the second seal plate 6 are both made of rubber sheets in which reinforcing cloths 10, 10 are embedded, and the pressure plate 5 and the presser plate 7 are made of steel plates. Of course, both the seal plates 4 and 6 may be constructed of a rubber sheet or a synthetic resin sheet without reinforcing cloth, and the pressure plate 5 and the presser plate 7 may be made of a metal plate other than a steel plate, a plastic plate, or a resin-impregnated plate. It may also be constructed of other hard materials such as a concrete board, a resin concrete board, a resin mortar board, or a hard rubber board.

The first seal plate 4 has a slight deflection 11 in the seam clearance 2.
Both side portions are in contact with the cutout step portions 9, 9 in the state in which they are provided. The pressure plates 5, 5 are stacked on both sides of the first seal plate 4, respectively, with a gap 12 provided at the position of the seam clearance 2. The second seal plate 6 has a large bending portion 13 in the center, and both sides thereof are overlapped with the pressure plates 5, 5, respectively. The holding plates 7, 7 are stacked on both sides of the second seal plate 6, respectively.

The anchor bolt 8 passes through both the seal plates 4, 6, the pressure plate 5, and the holding plate 7, and includes both sides of the first seal plate 4, pressure plates 5, 5, and both sides of the second seal plate 6. The holding plates 7, 7 are fixed to the underground structure 1 in a laminated state by applying nuts 14 to the anchor bolts 8.

Then, the width w of the gap 12 between the pressure plates 5, 5
is set smaller than a dimension 4t, which is four times the thickness t of the first seal plate 4. Note that a joint filler 15 is interposed in the joint gap 2.

In the above-mentioned joint 3, when there is no deviation between the underground structures 1 and 1, the joint material 15 bears the earth pressure and groundwater pressure, but if the sealing function of the joint material 15 weakens due to aging, etc., earth and sand etc. It invades play room 2. In such a case, the first seal plate 4 prevents dirt and the like from entering the inside of the underground structure 1. At this time, the earth pressure and underground water pressure are received by the pressure plate 5, and the first seal plate 4 is supported by the pressure plate 5 and does not extend and bulge inward of the underground structure 1. The reason why the relationship between the width w of the gap 12 between the pressure plates 5, 5 and the plate thickness t of the first seal plate 4 is set as w<4t is because the first
The purpose is to prevent the seal plate 4 from bulging out from the gap 12, and if the first seal plate 14 cannot pass through the gap 12 in a bent state, the above-mentioned bulge is prevented.

In this case, the dimension setting of w<4t is because when the first seal plate 14 is bent, a radius (R) is formed at the bent part, and a space with a width of about 2t is created inside the bent part. This takes into consideration the plate thickness t×2 and the space width 2t. However, the first seal plate 1
The space width inside the bend changes depending on the properties of 4 (physical properties of the rubber and reinforcing fabric, and the presence or absence of the reinforcing fabric), and w
It may be larger than 4t. The above 4t was obtained from experimental values without reinforcing cloth.

However, when the underground structures 1, 1 shift as shown in FIG. 3 due to uneven subsidence of the ground, an earthquake, etc. (in an abnormal situation), the first seal plate 4 breaks. At this time,
Since the air gap 12 of the pressure plates 5, 5 is located at the seam clearance 2 position, the above-mentioned displacement movement is allowed. Since the second seal plate 6 has a length margin in the flexible portion 13, it allows displacement of the underground structures 1, 1, and avoids breakage, and the second seal plate 6 allows the earth and sand to be transported underground. Intrusion into the interior of the structure 1 is prevented. Therefore, gas pipes, water pipes, electric wires, etc. inside the underground structure 1 are not damaged, and restoration work can be carried out from inside the underground structure 1 after the fact.

Note that the shape and amount of deflection of the flexible portion of the second seal plate can be changed and set appropriately as necessary. Further, when the cylindrical underground structure is made of steel or plastic, ordinary bolts can be used instead of anchor bolts.

Further, in the above embodiment, only the pressure plate on one side was made to protrude toward the play area, but the pressure plates on both sides may be made to protrude toward the play area.

(Effects of the Invention) According to the present invention, since the first seal plate and the second seal plate have a double seal structure, even if the underground structure becomes misaligned, the intrusion of earth and sand into the underground structure is ensured. can be prevented. Since a pair of pressure plates are provided and at least one pressure plate is made to protrude toward the play area, earth pressure and groundwater pressure can be received by the pressure plates, and the first seal plate prevents the bulge into the underground structure. is prevented. Therefore, the problem of the first seal plate aging rapidly due to continued elongation and deformation is resolved, and the sealing function is maintained for a long period of time. The second seal plate reliably performs its sealing function at times, prevents earth and sand from entering the underground structure in the event of an abnormality, and facilitates recovery after the fact.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention; FIG. 1 is a perspective view showing a partial cross section of an underground structure, FIG. 2 is a vertical sectional view showing a joint of the same structure, and FIG. 3 shows an abnormality in the joint. FIG. 1... Cylindrical underground structure, 2... Seam gap, 3...
...Joint, 4...First seal plate, 5...Pressure plate, 6
... Second seal plate, 7 ... Holding plate, 8 ... Anchor bolt, 12 ... Gap, 13 ... Flexible portion.

Claims (1)

[Claims] 1. At a joint between two cylindrical underground structures facing each other with a gap in between, both sides of the first seal plate are in contact with the inner peripheral surfaces of both cylindrical underground structures across the gap, and the first seal On both sides of the plate, each of a pair of pressure plates with a gap provided at the free space position, both sides of a second sealing plate having a flexible portion in the center, and a presser plate are stacked in order. Both sides of the seal plate, the pressure plate, both sides of the second seal plate, and the holding plate are fixed to the cylindrical underground structure with bolts in a laminated state, and at least one of the pressure plates protrudes toward the clearance side. A joint for a cylindrical underground structure, characterized in that the first seal plate is prevented from expanding inwardly of the cylindrical underground structure.