JPS5925051B2 - Earth retaining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earth retaining method for protecting the cut surface of the ground during root cutting work, such as when excavating the ground surface and constructing foundations and underground parts of buildings.

Conventionally commonly used earth retaining methods include the method of continuously driving steel sheet piles and concrete sheet piles, the parent pile horizontal sheet pile method using H-shaped steel and ■-shaped steel, and underground continuous walls for deep excavations. There are construction methods etc.

However, each construction method has advantages and disadvantages in terms of stability, strength, construction speed, materials, equipment, construction costs, and other aspects, and they are used depending on site conditions, construction scale, etc.

The earth retaining method of this invention is intended to rapidly construct an earth retaining structure with excellent stability using an expanded metal frame with relatively simple equipment.

The present invention will be described below based on illustrated embodiments.

Figures 1 to 3 schematically show the construction procedure of the earth retaining method of this invention. First, as shown in Figure 1 a e b, the first stage of excavation is carried out at the root cutting position, and the ground is immediately excavated. Extended metal frames (hereinafter referred to as frames) 1a and 1b, which are formed in a cross-sectional groove shape on the cut surfaces, are arranged in a grid pattern, and the case points are fixed with earth anchors 2, so that the cut surfaces of the earth and the frames 1a and 1b are arranged in a grid pattern. Bring 1b into close contact.

Next, as shown in FIG. 2a and b, frames 1a and 1
After fixing a predetermined number of stages b, mortar is sprayed to form the retaining beam frame 4 on the cut surface of the ground.

This operation is repeated to the required depth to complete the earth retaining beam frame 4 fixed with the earth anchors 2 shown in FIG. 3A-S-B.

Is this your first frame? It has appropriate bending rigidity to withstand rear earth pressure, and the expanded metal is formed into a groove shape in cross section, and the bottom surface is tightly fixed to the cut surface of the ground.

Note that after the earth retaining beam frame 4 is formed, this frame acts as a stiffener for the beam and constitutes an RC beam.

In addition, in order to form a lattice-shaped earth retaining beam frame 4 on the cut plane, the frame 1a is linear when viewed from the direction perpendicular to the cut plane for the part between the case points of the lattice, and the frame 1a is linear when viewed from the direction perpendicular to the cut plane, and the frame 1a for the case point part intersects with the case point as the center. By using the cross-shaped frame 1b, construction efficiency can be improved.

That is, by stacking the straight frame Ia on the bottom and the cross-shaped frame 1b on top, and fixing the cross-shaped frame 1b at the case point with the earth anchor 2, the entire frames 1a and 1b can be placed on the slope. Can be fixed.

At this time, frames 1a, 1bii' earth anchor 2
Due to the zero tension, the ground cutting is pressed against the surface, which suppresses the loosening of the ground, especially in the early stages.

Furthermore, since the frames 1a and 1b can follow even slight changes in the ground, shaping the ground is easy.

Figures 4 to 6 show the cross-sectional shapes of the cut surfaces of the ground in the construction method of this invention, and Figures 4 and 5 are sectional views A-A and B-B of Figure 2, respectively. Sectional view, No. 6
The figure is a sectional view taken along the line C--C in Figure 3.

As shown in the figure, since the space between each frame 1 in the vertical direction is excavated in an arch shape, arch-shaped earth pressure acts, and this arch action of the earth can suppress the extraction of the ground.

Further, by using a horizontal frame 1 that is curved in advance to match the arch shape, the work is facilitated and the frame 1 can be pressed against the ground cutting surface without difficulty and counteract the earth pressure.

Furthermore, the arch-shaped mortar 375 formed by spraying also resists pressure on the beak surface between the frames 1.

In addition, this construction method attempts to excavate to the lowest level while spraying mortar as early as possible, and since the frames 1a and 1b have appropriate rigidity, this construction method Others: ■ Excavate the first stage to the minimum height and at the same time attach the frames Ia and 1b to the earth anchors 2.
2. Or, spray mortar on the entire surface at the same time as the excavation, and then attach frames 1a, 1b and earth anchor 2 from above.
Possible methods include fixing the material and then spraying it.

In the case of method (2), the retaining beam frames 4 are formed by the first mortar spraying, and at the same time, the gaps between the beam frames are also protected by a layer of mortar.

The present invention has the above configuration and has the following advantages and features.

(1) By tightening an extended metal frame with appropriate bending rigidity with earth anchors, loosening of the ground can be suppressed at an early stage.

(]i) Since a certain amount of mortar can be sprayed all at once, the efficiency of earth excavation is greatly improved.

011) Since the frame has appropriate bending rigidity, it can be fixed in close contact with the ground.

4V) The middle part of the extended metal frame has an arching effect of the soil, and by fixing the frame part, it can prevent it from coming out.

(V) Shotting can also be prevented from being pulled out by using mortar, and by excavating an arch in front of the shotgun, the arch formed with mortar can resist back earth pressure.

[Brief explanation of the drawing]

Figures 1 to 3 show the construction procedure in an embodiment of the present invention, where Figure 1 is a front view of the cut surface during the first stage of excavation, Figure 1a is a side sectional view thereof, and Figure 2 Figure 2a is a front view of the cut surface when excavating a predetermined number of stages, Figure 2a is a side sectional view, Figure 3 is a front view when the earth retaining work is completed, Figure 3a is a side sectional view, and Figure 4 is a side sectional view. 2, FIG. 5 is a sectional view taken along line BB in FIG. 2, and FIG. 6 is a sectional view taken along line C-C in FIG. 3. 1.1a, 1b... Extracted metal frame, 2... Earth anchor, 3... Mortar, 4... Earth retaining beam frame.

Claims (1)

[Claims] 1. Excavate the ground surface of the excavated ground, place reinforcing expanded metal frames with a groove-shaped cross section on the excavated ground surface in a lattice pattern, and fix the points of this lattice with earth anchors. This is an earth retaining method in which the cut plane and the extended metal frame are brought into close contact with each other, and then mortar is sprayed to form the earth retaining beam frame. An earth retaining method that is characterized by being formed into a convex arch shape.