JPS6238488B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a continuous underground wall using a reference pile with a hollow section and an H-shaped cross section installed in a vertical hole. An H-beam steel pile with a hollow section is erected in the same hole as a reference pile, and the adjacent part is connected and closed excavated using a reverse circulation drill etc. using the reference pile as a guide. After erecting reinforcing bars, etc., concrete is poured to ensure a continuous underground wall with great depth and high precision.

Conventionally, as a method of constructing a continuous underground wall with great depth and high precision (hereinafter simply referred to as an underground wall), vertical holes are dug at appropriate intervals in the continuous direction of the underground wall, and an H-shaped cross section is inserted into the vertical hole. erect a steel pile with its recess facing the continuous direction of the underground wall, fill the inner surface of the vertical hole and the recess of the steel pile with gravel, install a reference pile for excavation, and then set the reference pile for excavation. There is a known method (Japanese Patent Publication No. 1891/1972) in which an underground wall is constructed by excavating between the piles, inserting reinforcing bars into the excavated hole, and then pouring concrete.

However, this conventional method has the following drawbacks.

(1) While excavating between two reference piles, gravel in the recess on the non-excavation side (back side) of the reference pile may flow down into the hole being excavated. When filling the hole with concrete, the concrete also fills the groove on the back side where the gravel has flowed down, making it impossible to excavate the next hole.

(2) The standard piles are bent due to the lateral pressure of the gravel filled in the hole, making it impossible to excavate between the standard piles.

(3) When excavating between the reference piles near the bottom of the reference piles, the lateral pressure of the gravel pushed the reference piles toward the excavation hole and caused them to move laterally, making it impossible to excavate between the reference piles.

Another method is to install a reference pile in a vertical hole, then use a reverse circulation drill or the like to excavate the area adjacent to the reference pile using the reference pile as a guide (connected excavation). Piles (general piles) are erected in the holes excavated by continuous excavation, and thereafter, the process of continuous excavation using the general piles as a guide and the process of erecting the general piles in the excavated holes is repeated to form piles (pillars). Methods of constructing columnar underground walls are also known.

However, with this method, errors in accuracy during connected excavation and errors in accuracy during general pile erection accumulate.
The drawback was that it was difficult to construct underground walls with high precision.

The present invention specifically eliminates such drawbacks of continuous underground wall construction and solves the related problems.

Therefore, the purpose of this invention is to reliably create a continuous underground wall with great depth and high precision, and the purpose of this invention is to prevent the reference pile from deforming or making it impossible to excavate adjacent areas. A further object of the invention is to provide a method that requires only one type of excavation machine, and a further object of the invention is to provide a construction method suitable for constructing an underground tank. There is something to do.

That is, the present invention, as shown in the illustrated embodiment,
Vertical holes 5 are excavated at predetermined intervals, H-shaped steel piles with hollow parts are erected in both vertical holes 5, the lower ends of the steel piles are reinforced, and concrete is poured into the hollow parts. Each reference pile 1 is placed inside the vertical hole 5 by applying a solidifying fluid material such as mortar between the outer surface of the flange, which forms both sides of the H-shaped steel pile in the width direction, and the inner surface of the vertical hole 5. is fixed, and using one of the reference piles 1 as a guide, a reverse circulation drill 4 or the like is used to continuously excavate the adjacent part of the one reference pile 1 to the other reference pile 1 side, and then the connected excavation is performed. Closed excavation is performed between the final stage of the previously excavated hole 26 and the other reference pile 1 using the respective reference piles 1 on both sides as guides to form a continuous groove between both reference piles 1. The present invention relates to a continuous underground wall construction method characterized by erecting H-shaped steel piles, reinforcing bar cages, etc. in an excavated trench, and then pouring concrete to form an underground wall.

Embodiments of the invention will be described with reference to the drawings.
In this invention, the H-beam steel pile with a hollow section (hereinafter referred to as a steel pile) has a shape in which two I-beam steels are fixed at their respective flanges, as shown in FIG. As shown in Fig. 2, a shape in which the respective flanges of two I-shaped steels are fixed via a lattice member, or a shape in other shapes is used.

Further, as shown in FIGS. 1 and 2, these steel piles may be used with seat backs 2 attached over the entire length between the flanges so as to cover the web portion (recessed portion), or may not be attached.

Next, the steps of the present invention will be explained step by step with reference to FIGS. 3 to 10.

(1) In advance, drive two rows of steel sheet piles between the planned underground wall locations to form the guide wall 3, and excavate approximately 2m deep between them. The top of the steel sheet pile should be aligned with the working ground.

(2) As shown in Figure 3 a and b, the guide wall 3
The inside is filled with a stabilizing liquid, and a vertical hole 5 for a reference pile is drilled at a predetermined position using a reverse circulation drill 4 (hereinafter referred to as a reverse excavator) or the like.
The vertical hole 5 is approximately 2.6 m in diameter and approximately 2 m deeper than the design length (adjacent hole). During excavation, the vertical hole 5 is filled with a stabilizing liquid to ensure the stability of the hole wall.
The accuracy of the drilling hole shall be 1/500 or more. The soil removal plan will initially be by pump suction, etc., and the rest will be by air lift method. Slime upon completion of excavation will be disposed of using a reverse excavator. Boulders, pieces of wood, etc. that are larger than the suction port diameter and are obstacles to the reverse excavator are obstacles to the progress of excavation, so break through these layers using a hammer grab, clam shell bucket, etc.

(3) Next, as shown in FIGS. 4a and 4b, the web part (recessed part) of the steel pile is erected in the vertical hole 5 in the direction in which the excavated hole continues, and is used as the reference pile 1. Seat back 2 is attached to steel piles divided into predetermined lengths (approximately 20 m), the upper and lower piles are held in place by a construction tower, and the piles are welded in sequence as they are erected. After the full length welding is completed, the pile is temporarily suspended at a position where the lower end of the pile is further away from the top of the cemented concrete at the bottom of the vertical hole.

(4) Next, as shown in FIGS. 5a and 5b, a tremie pipe 6 is installed in the vertical hole with the steel pile suspended, and concrete 7 for foot protection is poured into the bottom of the hole.
Immediately after driving, lower the steel pile into the specified position, or leave the steel pile suspended as it is and perform foot protection. The head of the steel pile will be fixed using steel from the steel sheet pile to prevent it from moving. The lower end of the sheet bag is shaped like a bag and is placed on the upper surface of the foot protection concrete 7. Although the seat bag is not necessary, for example, when solidifying the surrounding area of a steel pile with muddy water, in this embodiment, the explanation will be continued with a seat bag attached.

(5) Next, as shown in FIGS. 6a and 6b, muddy water is poured into the seat bag, and after the seat bag is welded to the inner surface of the vertical hole, gravel 8 (about 20 to 40 mm in diameter) is thrown into it. Concrete 9 is poured by a concrete pump into the hollow part of the steel pile and between the inner surface of the vertical hole and the flange part at a height that is equal to or slightly different from the height of this gravel, but the top positions of the gravel and concrete are not necessarily the same. There is no need to operate so that they are on the same level. The reference pile 1 may be positioned using gravel first.

As mentioned above, a method of solidifying the surrounding area of the steel pile with muddy water may also be adopted, or a method of filling the surrounding area of the steel pile with gravel and injecting silt mortar or bentonite mortar therein may also be adopted. . The reference pile 1 is made as described above.

(6) This reference pile 1 is
Holes are provided at appropriate intervals so that repeated drilling (double overlap drilling) is possible and the holes are continuous with a sufficient hole width. (FIG. 7) (7) Next, as shown in FIGS. 7a and 7b, using the reference pile 1 as a guide, a reverse excavator 4 or the like to which the guide frame 10 is attached is used to excavate the adjacent part in a continuous manner.

(8) Next, as shown in FIGS. 8a and 8b, a guide frame 10 is attached to the connected excavation side, and the flange of the reference pile 1 on the other side is used to prevent removal, and closed excavation is performed using a reverse excavator 4 or the like. At this time, the earth and sand that has fallen into the preceding connected excavation hole is sucked up by the air lift 11 that has been built in advance. Slime treatment after the completion of excavation is carried out using a reverse excavator 4 or the like and an air lift 11 combined with a jet.

(9) Next, as shown in Figure 9a and b, insert steel piles or reinforcing bars (not shown) into the holes between the reference piles 1 and 1.
Set it up in the same way as above, and hold only the head in place.

(10) Next, as shown in Figure 10a and b, after treating the inside of the erected steel pile with slime using an air lift,
Concrete is pumped by a concrete pump and placed inside the steel pile, and at the same time or before and after this, concrete is poured into the gap between the steel pile and the hole.
Fill with mortar or solidify muddy water.
Repeat the above steps to construct a continuous underground wall.

Next, with reference to FIGS. 11 to 13, detailed configurations of the apparatus during the above-mentioned continuous excavation and closed excavation will be explained. FIG. 11 shows an elevation of the drilling shaft, in which the drill pipe 12 is supported by the guide frame 10 via the swivel mechanism 13. 14 is a weight. Above it, attach the drill pipe 12 to the sudabi riser 1.
5 is installed. At the lower end of the drill pipe 12, in this example, a three-winged bit 1 with a stabilizer is attached.
6 is attached, and 17 is a collar-shaped weight.

FIG. 12 shows a stage corresponding to the continuous excavation shown in FIG. This indicates that an excavation groove 19 is dug in connection with the excavation hole 5. 20 is a weight attached to the guide frame 18.

FIG. 13 shows a stage corresponding to the closed excavation shown in FIG.
The extension guide frame 21 is attached to the base plate 1 with bolts or the like, and the guide frame 18 is placed along the reference stake 1 in the same manner as in FIG. A guide frame 18 with a weight 22 is attached to the opposite side of the guide frame 21 from the guide frame 10 with bolts or the like, and a guide frame 23 is attached to the weight 22 with bolts or the like.
This indicates that the excavation groove 25 is excavated using the reference piles 1 and 20 as respective guides. The purpose of the weights 20 and 22 is to balance the weight with the guide frame.

As is clear from the above description, the present invention has the following effects.

(1) Since concrete is poured into the hollow part of the steel pile, it has high rigidity as a reference pile, but when excavating the adjacent part, the steel material becomes deformed due to the lateral pressure of gravel packed into the recess, making it impossible to excavate. Things like this no longer occur.

(2) A solidifying fluid material such as concrete,
Either by filling with mortar, etc., or by filling with silt mortar, bentonite mortar, etc. after filling with gravel, or by filling with muddy water solidification materials, the standard pile is firmly fixed due to the adhesive force and frictional force of these materials. As a result, the steel pile no longer becomes deformed due to the lateral pressure of the gravel filled in the recess, making it impossible to excavate.

(3) When a sheet bag is strung between the flange, web and flange of a steel pile used as a reference pile, and gravel is filled in the bag, concrete will not get into the gravel. Furthermore, even in the method of solidifying muddy water without placing a sheet bag over the area, concrete will not get into this area. Therefore, it is easy to excavate a hole adjacent to the reference pile (connected excavation, closed excavation), and there is no longer a problem in the past where concrete wraps around and hardens into recesses, making it impossible to excavate.

(4) Steel piles used as standard piles are reinforced in advance, so
During excavation in the adjacent area, the steel pile no longer moves to the adjacent area due to the lateral pressure of the gravel. Therefore, it is no longer impossible to excavate due to this.

(5) Using accurately constructed reference piles as a guide, connected and closed excavations are performed in adjacent areas, making it possible to construct underground walls with high precision. Unlike the conventional method of connecting excavation using general piles as a guide, there is no accumulation of errors in accuracy.

(6) Depending on the purpose of the underground wall, it is also possible to adopt a construction method in which only concrete is poured without reinforcing bars or steel frames under the connected and closed excavations; in this case, it is naturally economical. become a target.

(7) Since excavation can be carried out with only one type of excavation machine, for example, a reverse excavator, it is economically advantageous and easy to handle.

(8) The construction method of this invention is suitable if applied to the construction of underground tanks.

[Brief explanation of the drawing]

Figures 1 and 2 are perspective views of an H-section steel pile with a hollow section used in carrying out the present invention, and Figures 3a, b to 10 a, b are plane views showing an embodiment of the invention. Figures and longitudinal cross-sectional views, Figures 11 to 13, show details of connected drilling and closed drilling, with Figure 11 being an elevational view of the drilling shaft, and Figures 12 and 13 being a cross-sectional view of the borehole. It is a front view. In the figure, 1 is a reference pile, 4 is a reverse circulation drill, 5 is a vertical hole, and 19 and 26 are excavated holes.

Claims (1)

[Claims] 1. Vertical holes are excavated at predetermined intervals, H-shaped steel piles with hollow sections are erected in both vertical holes, the lower ends of the steel piles are reinforced, and concrete is poured into the hollow sections. Each reference pile is fixed in the vertical hole by applying a solidifying fluid material such as mortar between the outer surface of the flange, which is both sides in the width direction of the H-shaped steel pile, and the inner surface of the vertical hole, Using one of the reference piles as a guide, use a reverse circulation drill or the like to continuously drill the adjacent part of one of the reference piles to the side of the other reference pile, and then drill the previously drilled hole in the final stage of the continuous drilling. A closed excavation is performed between the reference pile and the other reference pile using the respective reference piles on both sides as guides to form a continuous groove between the two reference piles, and in the thus formed excavation groove, an H-beam steel pile, A continuous underground wall construction method characterized by erecting a reinforcing cage, etc., and then pouring concrete to form an underground wall.