JPH03132524A - Reduction method of earth pressure against structure - Google Patents

Abstract

PURPOSE:To stabilize a back-filling section by forming a boundary plane between the back-filling section and back-sand into such a plane that combines an inclined angle generating no earth pressure from sand with an inclined angle capable of transmitting the earth pressure from the sand to the bottom of the back-filling section. CONSTITUTION:A back-filling section 2 of a structure 1 such as a retaining wall or an abutment or an underground construction, a steel sheet pile wall, etc. has independent efficiency, and the whole back-filling section 2 is combined to form. A boundary plane between the upper part of the back-filling section 2 and back-sand 3 is formed of a stabilized inclination A by properties of the back-sand 3. In addition, the boundary plane between the lower part of the back-filling section 2 and back-sand 3 is formed of an inclination B capable of transmitting earth pressure resultant force P from the sand 3 to the bottom of the back-filling section 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to 15 methods for reducing earth pressure on structures, particularly for reducing earth pressure on structures such as retaining walls and bridge abutments.
The present invention relates to a method for reducing

[Prior Art] Normally, l +'rg P acting on the back surface of a construct is calculated by 31 from the following equation 6J. (See Fig. 9) P = 1/2 KA・r ・r ("Here, the earth pressure coefficient r determined by the properties of KA20 (adhesive force, internal friction fQ): The upper unit small amount 1 - the acting surface (Wall) (1') IF...Construction,
2. Backfill area, 3. Back earth and sand.

The above formula is used to find the earth pressure acting on the alpha surface or temporary flooded sound surface of a structure, but since its magnitude is proportional to the square of the height, the height of the acting surface is As the soil pressure increases, the deep earth pressure becomes quite sensitive.

1 - The position of action of the resultant pressure is 1 from the bottom of the action surface (wall).
/3 position 5= is known. .

Conventionally, in order to reduce these earth pressures, high-quality earth and sand (with a large internal friction angle) were used in the backfilling part to reduce the earth pressure coefficient, and Qi of the backfilling part; Methods such as weight reduction have been attempted, but none of these methods involve injury to the backfilling part itself, so it can occur from the backfilling part or its backside.
The results show that tUt acts on the construct.

In addition, great advances have been made as a method for using the IF type in Jll, for example, in JP-A-51-456.
No. 2, JP-A-55-129594, or the former JP-A-62-458 and JP-A-62 filed jointly by the present applicant.
-99513 is known as a known technique.

However, these construction methods still have problems, such as the need to use a large amount of light materials depending on the quality of the back surface of the structure, and the difficulty in workability in some cases.

[Problem to be solved by the invention] The present invention was developed based on the following item 1-h, and aims to develop a construction method that can be used for any type of H or L material. The aim is to improve the stability and workability of the parts.

In order to carry out these construction methods, it is necessary to use an ultra-lightweight backing material (for example, if styrene foam is used, the unit weight is r = 0.03 to 0.01 t, f/m3,
This is equivalent to 1/80~]/1.00 of earth and sand), and the material itself has a high compressive strength, so by using it in combination, it is possible to create a self-supporting structure. A material that can be used for the backfill part.

This is necessary to ensure that the earth pressure due to the backfill material's own weight does not occur.

■In order to minimize or prevent the earth pressure acting from the upper sand on the backside of the backfilling portion from occurring, provide an inclination angle that does not generate -1-pressure at the interface between the backfilling portion and the backfilling earth and sand.

That is, the slope of the back earth and sand should be J The slope becomes a stable slope and at the same time no earth pressure occurs. In addition, since earth and sand have adhesive strength as well as internal friction angle, judging from the quality and inferiority theory, the stable slope angle is 2.
The culm degree is 9° to 33°.

■ Focusing on the position of the Ei pressure that acts from the back side of the backfilling section, we can take advantage of the fact that the foamed sugeger roll used for the backfilling section is a block body, so it can be installed in any shape.
Installation of the backfill section 1 so that the earth pressure from the upper back sand acts on the bottom of the backfill section [by installing it while forming a slanted angle, the earth pressure is not applied to the structure. I can do it.

For example, the inclination angle I3 with respect to the horizontal plane in Fig. 9 is 55°.
If it is set as below, the position of action of the resultant earth pressure force will be directed towards the bottom of the backfilling part and will not act on the structure. When the angle of inclination is 55° or more, the same effect can be obtained by extending the width across flats so that the position of action of the resultant soil pressure faces the bottom surface. .

[Means for Solving the Problems] The present invention has developed the following method in order to satisfy the conditions as described in F and use this as a construction method.

The method of the present invention will be explained below.

The backfilling part of a structure such as a retaining wall, abutment, underground structure, steel sheet pile wall, etc. is self-supporting, and the entire backfilling group is combined and integrated, and the backfilling part and the back surface sand are The boundary surface is formed into a surface that combines an angle of inclination that does not generate pressure from the back surface sand and an angle of inclination that allows earth pressure from the upper sand on the back surface to be transmitted to the bottom surface of the backfill section. It is.

``Operation J'' The present invention has the following method. When used, an inclination angle suitable for It forms a stable angle.

Therefore, the I-9 port can be used in any location, and the work becomes easier.
Coupled with the fact that it is extremely easy to process, it has the excellent effects of always constant work and stable Vjfi', η.

11 Examples] Next, the method of the present invention will be explained based on the drawings.

First, the definition of angle will be explained.

In the drawing, angle A is a stable inclination angle depending on the properties of the back earth and sand, and angle B is an angle of inclination that transmits the resultant soil pressure from the back earth and sand to the bottom of the backfill part. .

The backfilling part 2 used in the present invention can be made of any material, for example, a metal material, a material formed into a light concrete container shape, or a plotted body of these materials. As for easy-to-handle materials, ultra-light materials such as styrofoam blocks are preferred, and they can be made in any size, but in terms of the size suitable for the work. , a size of 2 m square and a thickness of about 50 cm is thought to be appropriate, but depending on the size of the angle formed, it can be formed as thin or as thick as -).

As shown in Figures 3 and 4, the angle of the boundary surface is determined by the number of layers of the ultra-lightweight body 8, for example, which is constructed by slightly rolling a styrofoam block into a stepped curve. It is composed of the ultra-lightweight body 8, which is connected to both the lower left and right sides of the body 4 by connecting fittings 4 as shown in FIG. Moreover, these are made to match the set angles A and B by changing the thickness according to the set angle.

Also, in the drawing, 1 represents structures such as retaining walls, 3 represents back earth, and l-1 represents -F up to the intersection of angle A and angle B.
1° represents the lower height.

Figure 1 shows that by providing a stable inclination angle A at the lower part of the backfilling part 2, P (resultant pressure force) is reduced according to the height H according to the above formula, and within the width of the four bases. Able to communicate 3.
This Koos is effective when the back surface sand is made of fine soil, such as sandy soil, clay-containing soil, etc., in which the 'i'-(17 ton lit) of 1' is large and the internal friction angle of - is small. Furthermore, even when the height of the working surface (wall) is high, the backfilling portion can be small and effective.

In FIG. 2, the portion 112 has a stable inclination angle A, so LVE does not occur. Therefore]] small ↑-resultant pressure P of 1 part
will be transmitted to the bottom surface. This case is effective when the soil type has a small unit weight of V and a large internal friction angle, that is, a viscous soil mixed with gravel becomes the backing soil. This is effective when the height of the working surface (wall) is relatively low.

Figure 3 shows a standard shape in which the angles of inclination A and B intersect at the center of the wall surface, and can be applied to a high quality intermediate between the above two cases. It is effective and economical when the height of the contact surface (wall) is relatively high.

Figure 4 shows the resultant force P
The force is transmitted to the lower surface of the backfilling portion 2. This case is effective when the unit weight of soil is large and the height of the working surface (wall) is low, regardless of the internal friction angle of -L.

Figure 5 is II, where no earth pressure occurs, II 2
The earth pressure resultant force P relative to +α is transmitted into the bottom surface. In this case, it is effective when the backing soil is made of fine quality, such as gravel, gravel, gravel, gravel, etc., which has a large unit weight and a large internal friction angle. It is also effective when the height of the working surface (wall) is relatively low.

The case in FIG. 6 is similar to that in FIG. 5, but the stability of the backfill portion 2 is emphasized. This case is effective when the back soil is made of solid soil, such as clay soil, sandy clay, etc., where the unit weight of the soil is small and the internal friction angle of the soil is small. It is effective and economical when the height of the contact surface (wall) is relatively low.

Although FIG. 7 is similar to FIG. 3, this slope is a preferable shape due to the L quality. The above two cases (Fig. 5 and 6)
(Example in the figure) can be applied to the intermediate quality. It is also effective (fL-) and economical when the height of the working surface (wall) is relatively low.

Fig. 8 is similar to Fig. 4, and utilizes the arch effect, and has the same effect in the case of high quality as in Fig. 7. In this case, seven inside one? Regardless of the friction angle, it is effective when the soil weight is small and the height of the working surface (wall) is high.Suitable soil types include sandy soil and sandy viscous soil. 1 clay-L mixed soil and sandy soil.

As shown in Fig. 1, when earth and sand 3 is placed on the backfilling part 20) 1-5, the weight of the sand 3 is placed on the bottom surface 6 of the backfilling part 2. This acts to increase the frictional force and prevent the action of the resultant force I) of the back surface sand 3 from affecting the structure l. Of course, if you ask me if I should increase the I-sand 3 in this part, the point is that if I increase the sand 3 in this part, the 1-pressure resultant force of the upper sand 3 in this part will act on the structure. Due consideration needs to be given. .

[Effect of the invention 1 O Since the present invention is a method as described above, it can be carried out regardless of the location of the construction work, and can be easily carried out in accordance with any situation.'' (L. Because the weight of the products handled is extremely light, the work is easy, and [1-] and addition []
Coupled with the fact that it is extremely easy to carry out, it has extremely remarkable effects such as constant work and stable work.

[Brief explanation of the drawing]

FIG. 1 is a detailed explanatory diagram of the present invention, showing a first embodiment, FIG. 2 showing a second embodiment, FIG. 3 showing a third embodiment, and a fourth embodiment. The figure shows the fourth embodiment, FIG. 5 shows the fifth embodiment, FIG. 6 shows the sixth embodiment, and FIG. 7 shows the seventh embodiment. Figure 8 also shows the eighth embodiment, Figure 9 is an explanatory diagram explaining the calculation of the resultant soil pressure, Figure 10 is an explanatory diagram of the stable slope angle, and Figure 11 is the same as Figure 3. Practical hb example, illustrative schematic diagram, 12th
The figure is a perspective view showing an embodiment of the connection press used in the present invention. 1 Figure 1 3, Figure 1... Structure, 2... Backfilling section, 3... Back top sand, A...
・Stable slope ff1.13・-1゛Transmission slope angle of resultant pressure force,
.

Claims (1)

[Claims] (1) The backfill part of a structure such as a retaining wall, abutment, underground structure, steel sheet pile wall, etc. is self-supporting, and the entire backfill part is combined and integrated, and the backfill part and back earth A structure characterized in that the boundary surface with the backfill is formed into a surface that combines an inclination angle that does not generate earth pressure from the back earth and sand and an inclination angle that allows earth pressure from the back earth and sand to be transmitted to the bottom surface of the backfill part. earth pressure reduction method for