JP2971045B2 - Casting method of bottom concrete in propulsion 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 method of placing concrete in a bottom of a shaft in a propulsion method, and more particularly to a method of placing concrete in a bottom slab to be cast as a foundation at the bottom of a shaft into which a steel pipe is press-fitted.

[0002]

2. Description of the Related Art Conventionally, when laying various pipes such as sewage pipes, water pipes, electric power pipes, gas pipes, and telephone line pipes in soil, a propulsion method using a small-diameter steel pipe press-fitting shaft has been adopted. I have. With this propulsion method, a cylindrical shaft of a predetermined depth is constructed as a starting shaft and a reaching shaft while maintaining an appropriate interval on the road surface, then concrete is poured into each shaft, and approximately at the middle of this shaft In this method, a propulsion pipe with a cutter and an earth discharging mechanism is made to enter in the horizontal direction, and is connected by a connecting pipe to bury a pipe body between the starting shaft and the reaching shaft.

[0003] The casting of the bottom concrete is indispensable in order to prevent water stoppage, boiling, heaving and the expansion of the clay layer in the shaft, and a conventional method of casting the bottom concrete will be described with reference to FIG. First, as shown in FIG. 1A, a self-propelled excavator main body 1 is installed on the site, and an excavating bucket 3a provided at a lower end portion of an excavating machine 3 inserted inside a casing 2 made of steel pipe. The shaft is excavated, and the casing 2 is press-fitted while discharging the earth. Shaft excavation is carried out using high-concentration mud or stable liquid as in the case of the Venoto method or earth drill method used in the construction of ordinary buildings, and sediment is sucked together with mud and discharged to the ground. Is mainly used.

[0004] Thereafter, as shown in FIG. 1B, a tremee pipe 4 is erected in the casing 2, and as shown in FIG. And then the bottom concrete 6 is completed as shown in FIG. The thickness of the bottom concrete 6 is 1.0 m to 1.5 m, which is thinner than the foundation concrete of a general building.

[0005] There are a rod type and a hose drum type as a method of draining a fluid used for excavation. The rod type includes a method using a vertical multi-axial or horizontal multi-axial type sludge steel pipe, and the hose drum type includes a hose hanging method, a vertical winding method, and a horizontal winding method. As an example, the order of execution of the construction method using a rod pipe will be briefly described. After preliminary excavation is performed by an open-cut excavator, main excavation and press-fitting are performed using a casing 2 and an excavator 3, and after the excavation is completed, Slime processing is performed by a slime processing machine. In the case of the hose drum type, a hose fed from a hose reel is suspended in a drilling hole, and mud is discharged through a hose from a sludge pump, thereby continuously excavating.

[0006]

However, when constructing a shaft used for such a conventional propulsion method,
There is a problem that slime, which is excavated waste, is caught in the poured bottom concrete 6 or the remaining muddy water is mixed into the ready-mixed concrete, thereby causing insufficient strength of the bottom concrete 6.

In particular, as shown in FIG. 2 (B), the slime 7 tends to remain on the bottom wall of the shaft, and the excavation bucket 3 is located between the inner wall surface of the cylindrical casing 2 and the bottom wall of the shaft.
Excavation residues 8, 8 due to the shape of a and the excavation performance often occur. In such a state, when the tremee pipe 4 is erected in the shaft and the ready-mixed concrete is poured as shown in FIG. 4C, the slime 7 is caught in the ready-mixed concrete and the remaining muddy water. Is likely to be mixed into ready-mixed concrete.

[0008] Further, between the bottom concrete 6 where the casting is completed and the inner wall surface of the casing 2 shown in FIG. In addition to the fact that the base concrete 6 is formed relatively thin, there arises a problem that the strength of the bottom concrete 6 is insufficient.

To cope with the above, in order to increase the water stoppage and strength in the shaft, there is also a means for injecting chemicals after placing the bottom concrete, but it requires extra man-hours and increases costs. Occurs.

In view of the above, the present invention has been made in view of the above, and prevents a decrease in the strength of bottom concrete caused by slime entrapment or mixing of remaining muddy water, and furthermore, it is not necessary to increase the number of man-hours. It is an object of the present invention to provide a method of placing bottom concrete in a propulsion method capable of reducing costs.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention constructs a cylindrical shaft by press-fitting a casing made of a steel pipe and digging a digging bucket using high-concentration muddy water. Insert a cylindrical ready-cast concrete casting bucket having an outer diameter slightly smaller than the inner diameter of the casing and suspended by wires, and lower the ready-cast concrete bucket to a position near the bottom wall of the shaft. By causing the high-concentration muddy water to rise in place of the ready-cast concrete placing bucket, a predetermined amount of ready-mixed concrete filled in the bucket is instantaneously discharged while the ready-cast concrete placing bucket is raised, and Disclosed is a method of placing concrete in a bottom layer in a propulsion method for placing concrete.

The shaft is excavated while using high-concentration muddy water or a stable liquid, and the soil and muddy water are sucked by a suction machine and discharged to the ground. In addition, an inlet for ready-mixed concrete is provided on the top wall of the ready-mixed concrete casting bucket, and an opening / closing mechanism for discharging ready-mixed concrete is provided on the bottom wall. Further, a claw body for scraping off a digging residue generated between the inner wall surface of the casing and the bottom wall portion of the ready-cast concrete casting bucket is attached to a peripheral edge of a lower end of the ready-cast concrete casting bucket. A predetermined amount of ready-mixed concrete required for placing the bottom concrete is previously filled in the setting bucket.

According to the method for placing bottom concrete, the excavator is inserted into the inside of the casing to excavate the cylindrical shaft using a high-concentration muddy water or a stable liquid and excavate the soil by using a drilling bucket. After the press-fitting, a cylindrical ready-cast concrete casting bucket, which is suspended from above the casing by a wire and pre-filled with a predetermined amount of ready-mixed concrete required for base concrete placement, is inserted. By moving the casting bucket up and down, the inner wall surface of the casing is cleaned with the action of pushing up the slime upward and the action of scraping off the digging residue by the claw body.

By lowering the ready-cast concrete bucket to a position near the bottom wall of the shaft, the high-concentration mud rises in place of the ready-cast concrete bucket, and the lower part of the bucket becomes almost anhydrous. The opening and closing mechanism is opened while raising the ready-casting concrete bucket, and a predetermined amount of ready-mixed concrete filled in the bucket is instantaneously discharged, and the bottom concrete is poured. Therefore, no slime is entrained in the ready-mixed concrete, or the remaining mud does not mix, and there is no digging residue around the obtained bottom concrete, so that the thickness of the bottom concrete is relatively small. The effect that the strength is maintained high even if formed is obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a concrete embodiment of a method for placing bottom concrete in a propulsion method according to the present invention will be described below by attaching the same reference numerals to the same components as those of the conventional structure. explain.

As shown in FIG. 1 (A), a self-propelled excavator main body 1 is installed at a site, and an excavator 3 is inserted into a casing 2 made of a steel pipe. The cylindrical shaft is excavated and discharged by the deployed excavation bucket 3a,
Press the casing 2 in. Excavation of this shaft is performed using high-concentration muddy water or a stable liquid as in the case of the Venoto method or the earth drilling method. Soil and muddy water are sucked by a suction machine (not shown) and discharged to the ground. At this time, excavation portions 8, 8 similar to the above-described conventional example exist between the inner wall surface of the casing 2 and the bottom wall portion of the shaft.

Next, the excavator 3 is moved to another place together with the excavator main body 1 and, as shown in FIG. The concrete casting bucket 12 is gradually inserted. The outer diameter of the fresh concrete casting bucket 12 is formed to be slightly smaller than the inner diameter of the casing 2 made of a steel pipe.

The ready-mixed concrete bucket 12 is a closed-type hollow body provided with an inlet for ready-mixed concrete on the upper wall and an opening / closing mechanism 13 for discharging ready-mixed concrete on the bottom wall. A claw body 14 is attached to the periphery.
Reference numeral 15 denotes a wire for opening and closing the opening and closing mechanism 13.

The ready-mixed concrete bucket 12 is pre-filled with a predetermined amount of ready-mixed concrete required for placing the bottom concrete from the concrete mixer truck 5. When the fresh concrete casting bucket 12 is inserted into the casing 2 and then raised as shown in FIG. 2C, the slime 7 remaining on the inner wall surface of the casing 2 is removed. When the claws 14 are opened and the ready-mixed concrete casting bucket 12 is lowered as shown in FIG. 4D, the excavated portions 8 are scraped off by the claws 14.
Therefore, the inner wall surface of the casing 2 is cleaned by moving the fresh concrete casting bucket 12 up and down.

Next, as shown in FIG. 3 (E), when the ready-mixed concrete bucket 12 is lowered to a position near the bottom wall of the shaft, high-concentration muddy water is applied to the ready-mixed concrete bucket 1.
As a result, the lower part of the ready-mixed concrete casting bucket 12 becomes substantially anhydrous. In this state, the opening / closing mechanism 13 is opened by tensioning the wire 15 while raising the ready-mixed concrete placing bucket 12,
A predetermined amount of ready-mixed concrete filled in the ready-mixed concrete placing bucket 12 is instantaneously discharged.

Then, as shown in FIG.
The concrete placing bucket 12 is pulled up while the tension of the concrete 5 is kept tensioned, whereby the placing of the base concrete 6 is completed. The slime 7 may remain on the upper surface of the cast bottom concrete 6, but there is no problem because the slime 7 is not involved in the ready-mixed concrete.

By placing the ready-mixed concrete in this manner, the slime 7 is caught in the ready-mixed concrete unlike the conventional method of placing a tremy pipe in a vertical shaft and placing the ready-mixed concrete. Therefore, there is no fear that the remaining muddy water may be mixed into the ready-mixed concrete.

Therefore, there is no digging residue 8, 8 around the obtained bottom concrete 6 and there is no slime entrapment or mixing of muddy water. Therefore, the thickness of the bottom concrete 6 is 1.0 m to 1.0 m. The strength can be maintained high despite being formed as relatively thin as 5 m.

[0024]

As described in detail above, according to the method for placing bottom concrete according to the present invention, an excavator is inserted into the inside of a casing while using a high-concentration muddy water or a stable liquid to excavate a bucket. By excavating a cylindrical shaft, press-fit the casing, insert a cylindrical ready-cast concrete casting bucket suspended from above by wire, and lower it to a position near the bottom wall of the shaft, thereby lowering the bucket. It is almost water-free, and a predetermined amount of ready-mixed concrete filled in the bucket is instantaneously discharged while raising the ready-cast concrete casting bucket, so that the bottom can be removed without slime entrapment or mixing of muddy water. Concrete can be cast.

Therefore, even if the thickness of the bottom concrete is relatively thin, the situation that the strength of the bottom concrete is insufficient due to slime entrainment or mixing of muddy water is prevented, and the number of man-hours is not particularly increased. ,
Construction work can be carried out smoothly and costs can be reduced.

Further, by moving the concrete casting bucket up and down in the casing, the slime is pushed upward and the claw body is used to scrape off the remaining portion of the digging, so that the inner wall surface of the casing can be easily cleaned. can do. As a result, there is no excavation residue around the obtained bottom concrete, so that the formed bottom concrete has an accurate columnar shape, and has an effect that the degree of completion is high structurally.

[Brief description of the drawings]

FIGS. 1A, 1B, 1C, 1D, 1E, and 1F are conceptual diagrams for explaining a method of placing concrete in a bottom floor to which the present embodiment is applied.

2 (A), 2 (B), 2 (C), and 2 (D) are conceptual views for explaining a conventional method of placing concrete in a bottom.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Excavator main body 2 ... Casing 3 ... Excavator 3a ... Excavation bucket 5 ... Concrete mixer truck 6 ... Bottom concrete 7 ... Slime 8 ... Excavation remainder 11, 15 ... Wire 12 ... Fresh concrete casting bucket 14 ... Claw body

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) E21D 1/00 E21B 11/00 E21D 9/06 301

Claims (5)

(57) [Claims] After a cylindrical shaft is constructed by press-fitting a casing made of a steel pipe and excavating a drilling bucket using high-concentration muddy water, the outer diameter of the casing is slightly smaller than the inner diameter of the casing from above. Inserting a ready-cast concrete cylindrical bucket suspended by a wire, and lowering the ready-cast concrete bucket to a position near the bottom wall of the shaft, the high-concentration muddy water and the ready-cast concrete bucket The bottom concrete in the propulsion method, wherein a predetermined amount of ready-mixed concrete filled in the bucket is instantaneously discharged and the bottom concrete is poured while raising the fresh concrete placing bucket in place. How to cast. 2. The method according to claim 1, wherein the excavation of the shaft is performed while using high-concentration muddy water or a stable liquid, and the soil and muddy water are sucked by a suction machine and discharged to the ground. Casting method. 3. The method of claim 1 or 2, wherein an inlet for ready-mixed concrete is provided on an upper wall portion of the ready-mixed concrete bucket, and an opening / closing mechanism for discharging ready-mixed concrete is provided on a bottom wall portion. Casting method. 4. A nail body for scraping off a digging residue formed between an inner wall surface of a casing and a bottom wall portion of a ready-cast concrete bucket is attached to a peripheral edge of a lower end of the ready-cast concrete bucket. Item 4. A method of placing concrete in the bottom in the propulsion method according to Item 1, 2 or 3. 5. In the ready-mixed concrete casting bucket,
5. The method according to claim 1, 2, 3 or 4, wherein a predetermined amount of ready-mixed concrete required for placing the bottom concrete is filled in advance.