JPS5894597A - Shecting wall for shaft pit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an earth retaining wall for a shaft, and more particularly to the structure of an earth retaining wall for a shaft having an upper earth retaining wall and a lower earth retaining wall having mutually different cross sections, and a connecting earth retaining wall connecting these. .

Generally, when a vertical shaft is excavated for concrete foundation construction or other purposes, a retaining wall is constructed in parallel with the excavation work to prevent the surrounding earth from collapsing. This earth retaining wall is usually constructed by assembling liner plates made of curved corrugated steel sheets, by pushing-in cylindrical concrete, or by combining molded and corrugated steel sheets. 4 are already in use.

When the cross-sectional change in the depth direction is small, such as in the case of a pier foundation, it is sufficient to install an earth retaining wall with a constant cross-section vertically, but when the change in the cross-sectional shape of the foundation in the depth direction is large, such as in the case of a steel tower foundation, or when the foundation is inclined. In this case, the cross-sectional shape of the retaining wall will need to be changed accordingly. This is because excavating a vertical shaft that covers the cross section of the foundation at all positions in the depth direction would be extremely uneconomical, as the amount of excavation would be abnormally large and foundation materials such as concrete would be wasted.

When constructing an earth retaining wall for a shaft whose cross section changes, cylindrical concrete is difficult to construct and cannot be used. Conventionally, liner plates are used for the electric cross section, and only the cross section section is changed. The work was carried out using a laminated structure of shaped steel and corrugated steel plates.

In this conventional method, the strength of the portion where the cross-sectional shape changes is extremely lower than that of the other portions where the liner plate is applied. Therefore, the liner plate type earth retaining wall, which is assembled using a construction method in which the liner plate is suspended and supported on the ground, has the disadvantage that it cannot hold the liner plate connected to the lower part. Ta.

In addition, the section with a changed cross section, which is a combination of shaped steel and corrugated steel plate, is an earth retaining wall that is constructed on-site, so it is insufficient not only in terms of strength but also in its ability to prevent soil infiltration, resulting in safety concerns. was also missing.

The purpose of the present invention is to eliminate such drawbacks of the prior art,
Even if there is a cross-sectional change part, as in the case of a constant cross-section,
To provide an earth retaining wall for a shaft that can be safely and efficiently constructed without unnecessary excavation.

A feature of the present invention is to use a connecting earth retaining wall having an upper flange, a lower flange, and a cover plate that connects these upper and lower seven flanges, thereby connecting the upper and lower earth retaining walls with different cross sections.

That is, according to the present invention, there is provided an earth retaining wall for a shaft having a cross-sectional change part including an upper earth retaining wall and a lower earth retaining wall having different cross sections and a connecting earth retaining wall connecting these,
The connecting earth retaining wall has a structure including an upper flange connected to the lower end surface of the upper earth retaining wall, a lower flange connected to the upper end surface of the lower earth retaining wall, and a cover plate that covers the entire surface between these seven lunges on both sides. There is provided an earth retaining wall for a shaft, which is characterized in that it is assembled by connecting this structure to both the upper and lower earth retaining walls with bolts or the like.Hereinafter, the present invention will be specifically described with reference to the drawings. Explain.

First, a method for constructing an earth retaining wall for a shaft using a liner plate will be explained with reference to FIGS. 1 to 6.

FIG. 1 is a diagram showing a liner plate, in which a corrugated steel plate 1 is curved in an arc shape with a predetermined curvature in the longitudinal direction as shown in the figure, and an upper 7 flange 2 and a lower flange 3 are attached to the upper and lower sides of the liner plate. are integrally formed by bending or welding. Furthermore, side flanges 4.5 are integrally formed at both ends by welding or the like. If there are multiple such liner plates, 4 to 10 pieces) are attached to the side flanges 4 and 5.
By connecting them with bolts, etc., a ring-shaped earth retaining wall is constructed.

When constructing an earth retaining wall, first, as shown in Fig. 2, a circular hole with a depth of about the width W of the liner plate (for example, 0.5 m) is excavated. The enforcement location is usually determined to encompass the entire foundation cross section at a given depth from the ground surface to a certain depth.

Next, as shown in Figure 3, a plurality of liner plates (5 at the locations shown) are connected in sequence to construct the top ring, and the space between the liner plates and the ground is backfilled. Compact the strata.

Next, as shown in FIG. 4, the uppermost ring is suspended and held by a holding frame formed of shaped steel 6 or the like and installed on the ground surface 7. This suspension is normally carried out so that the retaining wall is in a vertical position.

Subsequently, as shown in Fig. 5, excavation is further performed to a predetermined depth (for example, 0.5 m) so that each liner plate constituting the second stage ring can be assembled, and each liner plate is assembled.
Build a retaining wall up to the second stage.

The same work is then repeated to construct the earth retaining wall for the shaft. FIG. 6 is a diagram illustrating the assembly procedure of each liner plate, and shows that the earth retaining wall for a vertical shaft of a predetermined depth is constructed by assembling in the order of 1, 2, . . . 0.0.0.

When constructing an earth retaining wall with a constant cross section, the construction method described above can be used safely, but when the cross section changes midway through, the conventional method results in intermelting.

In other words, in the conventional method, the connecting earth retaining wall was constructed using a makeshift structure combining molded steel and corrugated plates for the section where the cross-section changes, which resulted in insufficient strength and the cross-section It was difficult to suspend and support different lower retaining walls on the ground surface. Another method is to fix a member such as another shaped steel to the section where the cross-section changes and separately record the lower retaining wall, but this method is extremely difficult to work with because it is installed within the strata.

The present invention provides an earth retaining wall for a shaft that can be assembled in the same manner as the cross-section-foot part, and can hold all of the lower earth retaining wall by simply fixing the uppermost part to the ground surface.

An embodiment of the earth retaining wall for a shaft according to the present invention will be described with reference to FIGS. 7 to 11.

FIG. 7 to FIG. 11 are diagrams illustrating the segment 10 constituting the connecting earth retaining wall according to the present invention.

Segment) 10 includes an upper flange 11 connected to the lower end surface of the upper retaining wall 20 (see FIG. 11) with bolts, etc., and a lower retaining wall 1! ! 30 (See Figure 11) A lower flange 12 connected to the upper end surface with bolts or the like, a cover plate 13 that is integral with both flanges and covers the entire surface between them, and side flanges 14 that are integrally formed on both sides. .15. In the illustrated example, a corrugated steel plate with excellent strength is used as the cover plate 13, but a flat plate may be used as long as the cover plate 13 has sufficient strength.

As shown in FIGS. 8 to 10, the overall shape of the segment 10 is an inwardly curved equi-connected trapezoid, and when a plurality of segments are connected in the circumferential direction (lateral direction), It has a size and shape that allows it to form a cone-shaped wall. That is, the illustrated example is a segment for configuring a connecting earth retaining wall 40 that connects a cylindrical upper earth retaining wall with a small diameter and a large diameter cylindrical lower earth retaining wall as shown in FIG. 11. .

When assembled in a ring shape, its upper end surface (the surface of the upper 7 langes 11) will have the same cross-sectional shape as the upper retaining wall, and its lower end surface (
The surface of the lower flange 12) has the same cross-sectional shape as the lower retaining wall. Therefore, the dimensions and shape of the segment 10 are determined by considering the shape and dimensions of the upper earth retaining wall and the lower earth retaining wall, as well as the number of circumferential divisions, and the dimensions and shape of all segments are kept the same as much as possible and one type of segment is used. It is preferable.

Fig. 11 A connecting earth retaining wall 4 having the above-mentioned configuration, which has the above-mentioned configuration, connects the L side earth retaining wall 20 made of a liner plate and the lower earth retaining wall having a large cross section also made of a liner plate.
FIG. 2 is a diagram illustrating a state in which the parts are connected and assembled at 0.

According to the embodiment described above, the upper earth retaining wall 20 is first constructed to a predetermined depth by the method described in FIGS. and drill each segment 10 in exactly the same way.
can be assembled. That is, each segment 10, which is divided so as to be assembled within the shaft, is connected one by one at its upper flange 11 with bolts or the like, and the segments are connected to each other at the adjacent side flanges 14 and 15 while going around the shaft. .

1' After the connecting earth retaining wall 40 is completed in this way, the lower earth retaining wall is assembled in the same manner as the upper earth retaining wall 20.

By repeating the above operations to the required depth, the earth retaining wall for a shaft having a section with a changed section will be completed.

In this case, the connecting earth retaining wall 40 can be designed to have sufficient strength (y and the same strength i as the - electric cross section), so the safety of the entire earth retaining wall can be ensured, and the lower earth retaining wall 30
can also be kept from the ground surface and can therefore be constructed using the same construction method as for constant cross-sections. In this way, retaining walls with cross-sectional changes can be constructed freely.
For example, when constructing a sloped foundation or a foundation with an enlarged cross-section at the bottom, there is no need to excavate a large hole with a constant cross-section that encompasses the entire foundation cross-section at the full depth, as was the case in the past. This eliminates extensive excavation work.

Since the entire surface of the connection retaining wall between the seven upper and lower lunges is covered with the cover plate 13, it is possible to reliably prevent earth and sand from entering the retaining wall, similar to the constant cross-section portion using liner plates.

In addition, each segment) 10 is integrally formed with 7 rungs 11, 12, 14, 15 around the entire circumference including the upper side, lower side, left and right sides, so that the connecting earth retaining wall 40 can be used for the purpose of connection. It also helps improve the strength of the

FIG. 12 is a diagram showing a main part of another embodiment of the present invention, that is, a segment (IOA) having a different structure. In this embodiment, the segment lOA uses a flat molded plate 13A, on which the upper seven flange 11A, the lower seven flange 12A1, and the side seven flange 14A, 15A on both sides are integrally formed by molding or welding. It is set up in Also,
Vertical ribs 16 and horizontal ribs 17 for reinforcement are provided on the inside of the flat cover plate 13A (7).

Since the segment 10A in FIG. 12 uses a flat plate as the cover plate 13A, the outer shape of the connecting earth retaining wall (40 in FIG. 11) obtained by assembling a plurality of these is a truncated polygonal pyramid. In this case, the inner edges of the upper and lower 7 flanges 11.12 are made into an arc shape to match the cross-sectional shape of the upper and lower retaining walls as shown in the figure, and are tightened through each flange surface, so that the sealing performance is initially limited. As in the case of the embodiment, there is no problem at all.

The embodiment shown in FIG. 12 also provides the same functions and effects as those explained with reference to FIGS. 7 to 11.

In addition, in the above embodiment, the case where the upper and lower earth retaining walls with a constant cross section has a circular cross section and the diameter of the lower side is large is explained.
The present invention is an ellipse or! The present invention can be similarly applied to a shaft retaining wall having an arbitrary cross-sectional shape, such as a cross section, and can also be similarly applied to a case where the lower retaining wall has a small cross-sectional shape.

Furthermore, the number and arrangement of the connection retaining walls 40 can be selected variously. For example, as shown in FIG. 13, two or three or more stages can be connected in succession, and
As shown in Fig. 4, the connecting earth retaining walls may be arranged so that the cross section changes a plurality of times via earth retaining walls having a constant cross section.

In addition, the upper earth retaining wall and the lower earth retaining wall in the above explanation refer to the earth retaining walls that are located above and below through a single-stage or multiple-stage connecting earth retaining wall, and if there are multiple cross-sectional changes, the middle earth retaining wall The same retaining wall may serve as both the upper and lower sides.

As is clear from the above description, according to the present invention, it is possible to obtain an earth retaining wall for a shaft having a cross-sectional change part that is excellent in workability and strength and can eliminate the need for extra excavation.

[Brief explanation of the drawing]

Figure 1 is a cross-section of an earth retaining wall - a perspective view illustrating the liner plate used to construct the machine section, and Figures 2 to 6 are diagrams showing how to construct an earth retaining wall for a shaft using the liner plate shown in Figure 1. An explanatory diagram illustrating the implementation procedure when constructing the earth retaining wall, FIG. 7 is a perspective view illustrating the segments constituting the earth retaining wall for connection of the earth retaining wall according to the present invention, and FIGS. 8 to 10 are the segments of FIG. 7. 11 is a perspective view showing an embodiment of the earth retaining wall for a shaft according to the present invention; FIG. 12 is a diagram showing a segment of the earth retaining wall for connection of the earth retaining wall according to the present invention. FIG. 7 is a perspective view showing another structural example. FIGS. 13 and 14 are explanatory diagrams showing examples of the arrangement of earth retaining walls for connecting earth retaining walls according to the present invention. l...Corrugated plate, 10. IOA...Segment (earth retaining wall for connection), 11. IIA--Upper 7 lunges, 12
．． 12A... Lower flange, 13, 13A... Cover plate, 14, 14A, 15, 15A... Side flange. 20... Upper earth retaining wall, 30... Lower earth retaining wall, 40.
・°Earth retaining wall for connection. Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, I] Figure 1, Figure 13, Figure 14.

Claims (1)

[Claims] (1) An earth retaining wall for a shaft having a cross-sectional change section including an upper earth retaining wall and a lower earth retaining wall with different cross sections, and a connecting earth retaining wall connecting these, wherein the connecting earth retaining wall is connected to the upper earth retaining wall. A structure having an upper flange connected to the lower end surface of the wall, a lower flange connected to the upper end surface of the lower earth retaining wall, and a cover plate covering the entire surface between these flanges,
An earth retaining wall for a shaft, characterized in that this structure is assembled by connecting this structure to both the upper earth retaining wall and the lower earth retaining wall with bolts or the like.