JPH0371529B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a method for easily removing an underwater temporary concrete continuous wall for constructing the foundation of an underwater structure after the foundation is constructed.

<<Background of the Invention>> When constructing a foundation for a bridge pier, etc., an artificial island is created by closing off a body of water, and the inside of the island is dug to be constructed.

By the way, when constructing a foundation under deep water, ordinary steel pipe sheet piles or steel sheet piles cannot sufficiently resist water pressure as the closure.

As a countermeasure in this case, it is possible to adopt continuous walls made of reinforced concrete as a closing structure.

However, with reinforced concrete continuous walls, the robustness that is a characteristic of concrete continuous walls has been an obstacle, especially when removing underwater exposed parts after construction of the underwater structure is completed.

This invention solves the above-mentioned problems, and aims to artificially create an unreinforced part in a continuous concrete wall so that this part can be removed as a brittle failure point.

In order to achieve the above-mentioned object, the method of the present invention involves connecting reinforcing bars of a continuous concrete wall in advance by connecting and connecting the upper and lower parts of the reinforcing bars with the water bottom surface as a separation part via a removable coupling tool, and connecting the reinforcing bars of a continuous concrete wall to the continuous wall. The continuous wall is placed in an exposed state on the surface of the wall, and when removed, the connecting joint is removed, and then an external force is applied to the underwater exposed part of the continuous wall, and the upper and lower parts are separated by using the separated part as a brittle fracture point. Features.

<<Operation>> According to the removal method having the above configuration, the continuous concrete wall can be separated into pieces of a certain size and shape, and removal work and transportation thereof can be easily performed.

<<Example>> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front sectional view showing the completed state of construction of a bridge pier to which the method of this invention is applied.

In the completed construction state shown in the figure, the concrete continuous wall 1 surrounding the pier is the closing point.
Inner concrete 2 is placed inside the basement,
A top plate 3 is placed on top of it, and the sea level is placed on top of it.
Pier 4 is being constructed that protrudes from the WL.

The concrete continuous wall 1 consists of a main body part 1a buried underground on the ocean floor and a temporary part 1b exposed in the sea and on the sea.

The purpose of the present invention is to separate and remove this temporary portion 1b as a separation portion E with the seabed as a boundary.

As shown enlarged in FIGS. 2 and 3, this cut-off section includes a pair of upper and lower U-shaped joints 5 and 6 that are connected to reinforcing bars arranged vertically inside the concrete wall, respectively. The flange joint surfaces of 5 and 6 are fastened with bolts 7 to connect the reinforcing bars on the main body part 1a side and the temporary part 1b side. Both joints 5 and 6 are placed in an exposed state on the wall surface of the continuous wall 1, and the exposed portions are covered with a protective sheet 8.

FIG. 4 is a perspective view showing the connection structure of the reinforcing bars in the same part, and the above-mentioned reinforcing bars 10 are arranged in tandem at appropriate intervals inside each joint 5, 6, and between the upper joints 6. are connected by round steel 11.

Note that the round steel 11 is coated, for example, on its outer periphery in order to prevent it from adhering to concrete.

Therefore, in order to remove the temporary part 1b of the continuous wall 1 constructed as described above, the interior surrounded by the continuous wall 1 is filled with seawater to balance the pressure with the open sea, and then the above-mentioned part is removed by underwater work. Connect bolts 5, 6
Next, as shown in FIG. 5, the chuck 15 of the bi-pro hammer 14 suspended from the crane 12 installed on a barge or the like is connected to the upper end of the temporary part 1b. By vibrating the vibrating hammer 14, the temporary part 1b is separated from the cut-off part E, which is the most fragile part.
It is possible to perform brittle fracture based on this point and remove this part as a cutting line.

As shown in FIG. 6, the concrete continuous wall 1 is constructed by pouring a succeeding panel 112 onto the end of a preceding panel 111 via a pouring joint 110. A diamond-shaped separation auxiliary hole 1 spanning each panel 111, 112
6 vertically, and when removing it, use the auxiliary hole 1.
When the chamber 6 is filled with an expansion agent, the expansion agent presses the wall surface as shown by the arrow. Here, the auxiliary hole 16 is a right-angled or acute-angled surface in each panel 111, 112, and generates an expansion pressure on the opposite side, and as a result, both panels 111 and 112 as a whole are shifted in opposite directions, and this portion can be sheared and separated. Therefore, by filling the auxiliary hole 16 with an expansion agent prior to vibration by the vibrating hammer 14, the temporary part 1b is separated at the bottom and both sides, and becomes a panel with a predetermined shape and size. Therefore, the transportation work after removal becomes easy. Examples of the shape of the auxiliary hole 16 in the concrete pouring joint part 110 include a shape in which the intersection of the part facing the panels 111 and 112 with the concrete pouring joint part 110 is an acute angle, as shown in FIG. 7a; As shown in b and c, curved shapes are considered, and the point is that both panels 1
The shape may be such that separation between 11 and 112 can be achieved most efficiently.

≪Effects of the Invention≫ As explained in detail in each of the examples above, according to the method of the present invention, when constructing an underwater structure, a strong closing structure with continuous concrete walls can be obtained, and sufficient durability can be achieved. Underwater structures and their foundations can be constructed using this system, and after construction is completed, the temporary parts exposed underwater can be easily separated by external force by removing connections such as bolts, making removal work easy. becomes.

In addition, as shown in the example, if a configuration is adopted in which auxiliary holes for separation are formed in advance at the joints of continuous concrete walls, the auxiliary holes can be filled with an expanding agent, making it easier to Can be separated.

[Brief explanation of drawings]

Fig. 1 is a front sectional view showing the completed state of construction of a bridge pier to which the method of the present invention is applied, Fig. 2 is an enlarged front sectional view of section A in Fig. 1, Fig. 3 is a side sectional view of the same, and Fig. 4 is the same side sectional view. A perspective view showing the connection structure of reinforcing bars in a part,
FIG. 5 is an explanatory diagram during removal work, FIG. 6 is a plan view of the concrete pouring joint, and FIGS. 7 a, b, and c are plan views showing other examples of shapes of auxiliary holes in the concrete pouring joint. 1... Concrete continuous wall, 1a... Main body part,
1b... Temporary part, 2, 3... Foundation (2... Inner wrap concrete, 3... Hinge), 4... Pier (underwater structure), 5, 6... Joint, 7... Bolt, 10
...Reinforced steel.

Claims (1)

[Claims] 1. A method in which a body of water is closed off by an underwater temporary concrete continuous wall, a foundation for an underwater structure is constructed inside the closed-off, and the upper part of the water bottom surface of the continuous wall is removed after construction of the foundation is completed, the method comprising: The reinforcing bars are connected in advance through removable connectors between the top and bottom of the water with the water bottom surface as a separation part, and the connectors are placed in an exposed state on the wall surface of the continuous wall, and when removed, A method for removing an underwater temporary concrete continuous wall, characterized in that the connecting joint is removed, and then an external force is applied to the underwater exposed part of the continuous wall to separate the top and bottom by using the separated part as a brittle fracture point.