JP3255380B2 - Concrete casting method with separation layer in continuous wall method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete casting method using a separation layer in a continuous wall method.

[0002]

2. Description of the Related Art In a continuous wall construction method, a concrete continuous wall is constructed by replacing muddy water with cast concrete.

[0003]

SUMMARY OF THE INVENTION In general. When the concrete and the muddy water come into contact, the concrete and the muddy water are mixed and gelled at the boundary surface, and the replacement of the muddy water by the concrete is hindered, the muddy water replacement efficiency is deteriorated, and the quality of the continuous wall is reduced.

[0004] It is an object of the present invention to provide a concrete placing method using a separation layer in a continuous wall method for improving the efficiency of replacing muddy water with concrete.

[0005]

According to the concrete casting method using a separating layer in the continuous wall method according to the present invention, a reinforcing steel cage is erected in an excavation trench filled with muddy water and concrete is poured. In the concrete placing method by the separation layer in the above, the mixed liquid consisting of fresh water, metal salt and mud is not gelled for concrete and mud, specific gravity is larger than mud, and viscosity is larger than mud and smaller than concrete. Preparing, laying a tremy tube in the reinforced cage, injecting the mixed solution from the tremy tube, and then driving concrete from the tremy tube to separate the mixed layer between the muddy water layer and the concrete layer. The upper surface of the poured concrete pushes up muddy water and replaces it.

[0006]

[0007]

[0008]

[0009]

The metal salts include CaCl, NaCl,
It is preferable to use Kcl or the like.

Further, it is preferable that the chemicals shown in Table 1 be used as the mud dispersant.

[0012]

[0013]

Therefore, when the mixed liquid is injected from the tremee pipe, the mixed liquid is heavier than the muddy water, and accumulates at the bottom of the digging groove. When concrete is poured through the tremie pipe, concrete having a specific gravity higher than that of the mixture further accumulates in the lower portion of the mixture, and as a result, a separation layer of the mixture is formed between the muddy layer and the concrete layer. As described above, since the concrete does not come into direct contact with the muddy water and does not become quenched when the mixed liquid is used, the muddy water is more appropriately replaced with the concrete.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the excavation groove 1 is filled with muddy water A, and a steel cage 2 is built in the excavation groove 1.

Prior to concrete placing, a tremy tube 3 is erected in the reinforced cage 2.

At the time of placing concrete, first, a predetermined amount of a mixed solution B of fresh water, a metal salt, and a dispersant of mud is poured from the hopper 4 of the tremy tube 3. The mixed liquid B is compatible with the concrete C and the muddy water A, that is, is opposite to gelling, has a specific gravity larger than the muddy water by, for example, 0.1 or more, and has a viscosity larger than the muddy water A and smaller than the concrete C. Required. In addition, metal salts include C
aCl, NaCl, Kcl and the like are used, and the chemicals shown in Table 1 are used as the mud dispersant. The predetermined amount is such that the height H of the separation layer 11 described later is, for example, 50 cm to 50 cm.
An amount of 100 cm is preferred.

Next, as shown in FIG.
Then, the concrete C is dropped from the hopper 4 and dropped. When the dropping stops, the tremy tube 3 is pulled out. Then, the concrete C is sequentially driven from the bottom of the excavation groove 1 through the bottom opening of the tremy tube 3 as shown by the arrow, and the upper surface of the driven concrete C pushes up and replaces the muddy water A as shown by the arrow. At this time, since the specific gravity of the mixed solution B is smaller than that of the concrete C and larger than that of the muddy water A, a mixed liquid layer having a height H, that is, a separation layer 11 is formed between the muddy water layer 10 and the concrete layer 12. Therefore, since the muddy water A and the concrete C do not come into direct contact with each other, the conventional problem caused by gelation is eliminated.

[0019]

As described above, according to the present invention, the following excellent effects can be obtained. (A) The separation layer prevents gelation due to direct contact between concrete and muddy water, and improves muddy water displacement efficiency. (B) Since the specific gravity of the mixture forming the separation layer is between the muddy water and the concrete, the shape of the separation layer is assured. (C) What is necessary is just to prepare a liquid mixture, and the conventional apparatus can be applied as it is.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view illustrating an embodiment of a mixed liquid injection.

FIG. 2 is a vertical cross-sectional view illustrating a concrete driving mode.

[Explanation of symbols]

 A: muddy water B: mixed liquid C: concrete H: separation layer height 1: excavation groove 2: reinforced cage 3: tremy pipe 4: hopper 10. ..Muddy layer 11 ・ ・ ・ Separation layer 12 ・ ・ ・ Concrete layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) E02D 5/20 101-102 E02D 5/18 101-102 E02D 15/06

Claims (1)

(57) [Claims] 1. A concrete casting method using a separating layer in a continuous wall method in which a reinforcing bar is erected in an excavation trench filled with muddy water, and concrete is casted. And preparing a mixed solution having a specific gravity larger than that of muddy water and a viscosity larger than that of muddy water and smaller than concrete without being gelated with respect to muddy water, setting a tremy tube in the reinforced cage, Then, concrete is poured from the tremie pipe to form a separation layer of the mixed liquid between the muddy water layer and the concrete layer, and the upper surface of the injected concrete pushes up and replaces the muddy water. Concrete placement method using separation layer in continuous wall method.