JPH04102623A - Construction method for cut-off caisson - Google Patents

Abstract

PURPOSE:To form a dry space in an inside enclosed by a caisson by setting the caisson furnished with an opening section at the bottom surface, which coincides with a channel on riprup mound furnished with the channel connected to a rock mass, and thereby integrating both of them into one by means of concrete placing in water. CONSTITUTION:A riprup mound 1 is first formed with a channel 2 by the use of a cut-off block 3 made of concrete, which is made up out of double wall panels faced to each other, and of a periphery plate. In the second place, a cut-off zone 33 made of impermeable material is set by making use of a spacer consisting of the cut-off block 3. On the other hand, in constructing the caisson, an opening section is provided at a position which coincides with the channel 2 when the caisson is rested on a mound 1, the caisson is carefully lowered down therefore in such a way that both of them mutually coincide with, so that it is thereby rested on the mound 1. Following which, reinforcing bars are then placed while both of the channel 2 and the opening section are being penetrated through, and when concrete is placed in water until it reaches an under water rock mass, the mound 1 is completely integrated with the caisson, so that a cut-off wall is thereby formed.

Description

[Detailed Description of the Invention] \Construction of Ear Mound If earth and sand are deposited on the seabed, the earth and sand are removed to expose the seabed bedrock.

Mound 1 is constructed by dumping rubble from a rubble boat onto the exposed bedrock and piling it up to a predetermined height.

〈Opening of a groove A groove 2 is opened in this rubble mound 1 to a depth that reaches the bedrock.

However, even if the groove 2 is opened directly in the rubble, the surrounding walls will collapse immediately and the groove 2 will be buried.

Therefore, a water stop block 3 made of concrete as shown in FIG. 2 is used.

This water stop block 3 consists of two long wall plates 31 facing each other.

Between these wall plates 31, spacers 32 made up of narrow plates are interposed at appropriate intervals ti, so that both wall plates 31
are formed at a certain interval.

The height of this wall plate 31 corresponds to the depth of the groove 2 formed in the mound l.

Then, a vertically erected waterstop 33 is applied to the plurality of spacer groups 32 in a state where they are connected to each other.

This water stop strip 33 is made of a water-impermeable material such as synthetic resin, and by installing it vertically, the water passage between both sides can be extended, resulting in improved water stop performance. .

Further, no bottom plate is provided between both wall plates 31, and the structure is configured in an open state.

In addition, on the upper part of both wall plates 31, there is an edge plate 3 that protrudes toward the foreign bond.
4 will be provided.

(c) Structure of the caisson The overall shape and structure of the caisson 4 are the same as those of the conventional one.

However, as shown in Figure 3, the canon 4 used in the present invention has an opening [gc] 42 in the bottom surface 41 of the same position and size as the groove 2 described above.

The starting position is the position where the groove 27 that has already been excavated coincides with the caisson 4 when it is placed on the mound.

This opening 42 has the same width as the groove 2 from one end of the bottom surface 41 of the T-son 4 to the other end.

However, there is a partition wall above the opening 42, and the bottom surface 41 is simply
Since the opening is t, there is nothing that could affect the strength of the caisson 4 structure.

Installation of the caisson 4 - 1 - Protect the wall of the groove 2 from collapse as described above by using a well water pro 27 3, and then install the caisson 4 above.

In the case of this installation, the groove 2 of the mound 1 and the open part 42 of the caisson 4 are gently hung down with -'1z-3.

<E/After pouring the concrete, assemble the reinforcing bars so that they pass through the groove 2 and the inside of the opening 42.

Next, underwater concrete is placed in the groove 2 and the opening 42 as one piece.

Since submarine bedrock is exposed at the bottom of trench 2, concrete can be filled up to the bedrock.

As a result, a key is fitted into the contact surface between the mound 1 and the caisson 4, and the two are completely integrated via the key, and a water-stop wall reaching the bedrock is formed.

Of course, if you are concerned about the water-stopping properties of the bedrock itself, you can use conventional methods such as curtain grout (c).

<Effects of the present invention> As described above, the present invention is a method of forming a water-stop wall that reaches the bedrock in a state where the contact portion between the mound and the caisson is cut off.

Therefore, it is possible to completely prevent water from flowing from one side of the caisson to the other, and as a result, one side of the caisson can be drained and work can be done in a dry state, greatly improving work efficiency. Is possible.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of the completed state of the construction method of the present invention. Figure 2: An explanatory diagram of the water stop block used in the construction method of the present invention. Figure 3: An explanatory diagram of the structure of a caisson.

Claims (1)

[Claims] (1) Pile up rubble on bedrock to form a mound,
In the method of installing a caisson on top of the rubble mound, a groove is created in the rubble mound that reaches the bedrock, and the side walls of this groove are suppressed to prevent collapse. An opening with the same dimensions is prepared in a position that will match the groove when installed on top of the rubble mound, and the caisson is installed on top of the rubble mound with the groove in the mound and the opening in the caisson aligned. death,
A method of constructing a water-stop caisson, which is then constructed by integrally pouring underwater concrete into the groove and inside the opening.