JPS6256297B2 - - Google Patents

Description

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

(Prior art) When cylindrical underground structures are formed of concrete, a joint material such as rubber or asphalt impregnated material is interposed in the joint gap as a joint when connecting the cylindrical underground structures in series. Simple joints that prevent earth and sand and groundwater from entering underground structures are conventionally known. However, with this type of joint, the joint material is always subject to high earth pressure or groundwater pressure, so there is a risk that it may separate from the joint gap, so a high sealing function cannot be expected, and it may cause uneven settlement of the ground.
If the joints of an underground structure shift due to an earthquake, etc., the joint material may come off, or if the joint material is embedded and fixed in the underground structure, the joint material may be severed, causing a large amount of soil and groundwater to leak underground. There is a problem in that they invade structures, making recovery after the fact extremely difficult.

(Objective of the Invention) The basic purpose of the present invention is to improve the sealing performance of joints for cylindrical underground structures, and further improve the sealing performance even in abnormal situations such as earthquakes and uneven ground subsidence. The purpose is to be able to maintain Furthermore, the present invention makes it possible to provide such a joint with high sealing performance at a low cost.

(Structure of the Invention) The joint for a cylindrical underground structure according to the present invention has two seal plates, a pair of holding plates, a bolt, and a swellable rubber as main components. The first seal plate is brought into contact with the inner peripheral surfaces of the two opposing cylindrical underground structures across the joint gap. The second seal plate has a flexible portion on the center side, and both sides of the flexible portion are in contact with the first seal plate. The pair of presser plates are respectively abutted on both sides of the second seal plate. Then, both the seal plates and the presser plate are fixed to the cylindrical underground structure with bolts. The swellable rubber is interposed between the cylindrical underground structure and the first seal plate at an intermediate position between the bolt and the gap, and over the entire circumference of the cylindrical underground structure. Here, the term "swellable rubber" refers to rubber that expands in volume by absorbing moisture.

Therefore, in the joint according to the present invention, the joint portion of opposing cylindrical underground structures is doubly sealed by the first seal plate and the second seal plate. When the ground is normal, the first seal plate mainly performs the sealing function to prevent earth and sand from entering the underground structure, and at this time, the second seal plate is not affected by the earth and sand. , the bending portion also maintains its bending state. Therefore, in the event of an abnormality in which the opposing underground structures shift at the joint, the first seal plate will break, but the second seal plate will not break, allowing the above-mentioned shift due to the margin at the bending portion. In other words, in the event of an abnormality, the second seal plate performs a sealing function.

In a normal state when the first seal plate is not broken, the swellable rubber absorbs water such as ground water that enters through the gap and expands in volume compared to the initial state of installation, and forms a cylindrical shape with the first seal plate. It comes into close contact with the underground structure under high pressure and prevents groundwater etc. from entering the bolt side, thereby preventing corrosion of the bolt and leakage of groundwater etc. into the cylindrical underground structure.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

A cylindrical underground structure 1 is shown in FIG.
This underground structure 1 is made of concrete, and the two underground structures 1, 1 are arranged facing each other with a joint gap 2 between them. Next, this underground structure 1,
The specific structure of the first joint will be explained.

The joint 3 of this embodiment is shown in FIGS. 2 and 3, and includes a first seal plate 4, a second seal plate 5, holding plates 6, 6, anchor bolts 7, 7, and swellable rubber 14, 14. is the main component. The underground structures 1, 1 have cutout steps 8, 8 formed at the inner circumferential ends of their joints, and these cutout steps 8, 8 have grooves embedded in the underground structures 1, 1. However, the anchor bolts 7, 7 are protruding.

The first seal plate 4 is a rubber sheet with a reinforcing cloth 9 embedded therein, and both sides thereof are in contact with the notch steps 8, 8 with a slight flexure 10 provided in the joint gap 2.

The second seal plate 5 is a rubber sheet containing a reinforcing cloth 11 like the first seal plate 4, and has a large inward bending part 12 in the center, and the first seal plate 5 has a large bending part 12 in the center.
It is in contact with both sides of the seal plate 4.

The holding plates 6, 6 are both made of metal, plastic,
resin impregnated board, concrete, resin concrete,
It is made of a hard material such as resin mortar or hard rubber, and is applied to both sides of the second seal plate 5 from the inside.

The anchor bolt 7 passes through both the seal plates 4, 5 and the presser plate 6, and the anchor bolt 7 passes through the seal plates 4, 5 and the presser plate 6.
It is fixed to the underground structure 1 using nuts 13.

Further, a swellable rubber 14 is interposed between the first seal plate 4 and the notch step 8 so as to be located closer to the joint gap 2 than the anchor bolt 7. This swellable rubber 14 absorbs moisture and expands in volume. Further, a joint material 15 is interposed in the joint gap 2.

In the above-mentioned joint 3, when there is no misalignment between the underground structures 1, 1, the joint material 15 bears the earth pressure and groundwater pressure, but when the sealing function of the joint material 15 weakens due to aging etc. Earth and sand may enter the joint gap 2. In such a case, the first seal plate 4 prevents earth and sand from entering the inside of the underground structure 1. Therefore, the second seal plate 5 is not affected by earth and sand, underground water, etc., and is not damaged or aged by these earth and sand, and maintains its original state when installed. Further, the swellable rubber 14 attempts to expand in volume by absorbing water such as ground water, but the first seal plate 4 remains pressed against the notch step 8 due to the tightening force of the anchor bolt 7. For,
The swelling rubber 14 comes into close contact with the first seal plate 4 and the cutout step 8 under high pressure (in a compressed state) due to the expansion force caused by the absorption of water, thereby preventing underground water etc. from entering the anchor bolt 7 side. This prevents corrosion of the anchor bolt 7.

If the two underground structures 1, 1 shift at the joint as shown in FIG. 3 due to uneven subsidence of the ground, an earthquake, etc., the first seal plate 4 will break. On the other hand, since the second seal plate 5 has a length margin in the flexible portion 12, it can allow the underground structures 1, 1 to shift and avoid breakage. The second seal plate 5 prevents dirt and the like from entering the underground structure 1. 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.

In addition, although the reinforcing cloth is embedded in each seal plate in the above embodiment, the reinforcing cloth may not be embedded in some cases.

In addition, the shape and amount of deflection of the flexible portion of the second seal plate can be changed and set as necessary.

Further, although the above embodiment relates to a joint for a cylindrical underground structure made of concrete, the present invention can also be applied to underground structures made of steel or plastic by using ordinary bolts instead of anchor bolts.

(Effects of the Invention) According to the present invention, since the double seal structure includes the first seal plate and the second seal plate, intrusion of earth and sand into the underground structure is reliably prevented.
The swellable rubber improves the sealing performance between the underground structure and the first seal plate, thereby preventing corrosion of the bolts due to groundwater and the like, and further preventing leakage of groundwater and the like into the underground structure. In addition, since the second seal plate having a flexible portion is positioned inside the first seal plate, when the first seal plate receives dirt, etc., the second seal plate does not come into contact with the dirt, etc. It maintains its original condition by avoiding damage from earth and sand and deterioration from groundwater, and when the first seal plate breaks, it reliably performs its sealing function to prevent earth and sand from entering the underground structure, making recovery possible after the fact. Make it easy.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing a partial cross section of the underground structure;
FIG. 2 is a longitudinal cross-sectional view showing a joint of the same structure, and FIG. 3 is a cross-sectional view showing the state of the joint in the same structure when an abnormality occurs. 1... Underground structure, 2... Joint gap, 3... Joint, 4... First seal plate, 5... Second seal plate,
6... Holding plate, 7... Anchor bolt, 12...
Flexible portion, 14... Swellable rubber.

Claims (1)

[Claims] 1 At a joint between two cylindrical underground structures that face each other with a gap in between, both sides of the first seal plate abut against the inner peripheral surfaces of both cylindrical underground structures across the gap, and the first seal Both sides of a second seal plate having a flexible portion on the center side abut against the plate, presser plates abut on both sides of the second seal plate, the first seal plate,
A second seal plate and a holding plate are fixed to the cylindrical underground structure with bolts, and a swellable rubber tube is provided between the cylindrical underground structure and the first seal plate at an intermediate position between the bolt and the gap. A joint for a cylindrical underground structure, characterized in that it is interposed around the entire circumference of the cylindrical underground structure.