JP2000303466A - Earth retaining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow a soil improvement scope obtained by earth retaining piles by mixing excavated soil, surplus soil except excavated soil, a hardener, and lightweight material and forming an earth retaining wall having a specified unit volume weight, in the ground outside of an excavating zone. SOLUTION: Columnar piles are erected by a continuous wall construction method or the like making use of a mechanical agitation method, a high pressure cross jet stream method, a high pressure jet stream method and many columnar piles are arranged in sseries to form an aerth retaining wall 1. In this time, a material containing excavated soil, surplus soil except excavated soil, a hardener, and a lightweight material is used as a lightweight hardener. The hardener in the lightweight hardener or the lightweight material are mixed so that a unit volume weight after formation of the earth retaining wall 1 ranges within 0.6-1.3 ton/m3. In this way, since increase of the lateral pressure caused by the own weight can be prevented, soil improvement scope of vertical pile rows 3-6 can be made narrow as W1 and it can be adapted in a narrow site without invasion of adjoining boundary. Further, since the pile length H2 (<H1) of the vertical pile rows 3, 4 is short, raw materials can be saved and the construction efficiency can be improved and the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth retaining method using lightweight earth retaining walls.

[0002]

2. Description of the Related Art As an earth retaining method for preventing collapse of the surrounding ground at the time of excavation, for example, a soil retaining wall made of a sheet pile or the like is cast, and while excavating the inside thereof, the lateral pressure acting on the earth retaining wall is reduced. A construction method that supports by the compression resistance of the cutting beam passed between the retaining walls, and a gravity-type retaining wall-like soil structure is formed in the ground outside the excavation area by stirring and mixing ground hardening material such as cement. Earth retaining method using a structure
252817), a method of forming a column by stirring and mixing a soil hardening material along the outer edge of an excavation area, and retaining the soil with the column (Japanese Patent Publication No. 60-49735).

[0003]

However, the earth retaining method for supporting sheet piles with cut beams has a low efficiency in underground work due to the presence of cut beams inside, and it is difficult to secure safety. There is a problem that is not easy. In the method of forming a columnar body or a gravity-type retaining wall-shaped earth structure as an earth retaining wall, a cement-based solidifying material is used as a hardening material or a solidifying material, so that the unit volume weight of the earth retaining wall is 1.
Although it has a function of supporting the earth pressure generated by root excavation in the range of 6 to 1.7 tons / m ³ , it also increases the lateral pressure by its own weight. In addition, when the excavation becomes deeper, the earth pressure increases, and there is a problem that the soil improvement range by the retaining pile is widened and affects the boundary of the adjacent land.

Accordingly, it is an object of the present invention to provide an earth retaining method capable of narrowing the ground improvement range using earth retaining piles, enabling application in a narrow site, and reducing the construction cost.

[0005]

Under such circumstances, the present inventors have made intensive studies and as a result, as a solidifying material to be used when constructing a retaining wall, a solidifying material is used instead of the conventional cement-based solidifying material. If a retaining wall with a unit volume weight of 0.6 to 1.3 tons / m ³ is used, the weight of the retaining wall itself is reduced, and the lateral pressure due to its own weight is used. Can reduce the increase in soil, so that the range of ground improvement by retaining walls can be narrowed, and it can be applied in narrow sites, and the length of improvement can be shortened, resulting in a significant reduction in cost. Thus, the present invention has been completed.

That is, a first aspect of the present invention is an unreinforced wall-like body in which excavated soil, remaining soil other than excavated soil, a solidified material, and a lightweight material are mixed in the ground outside the excavated area. An earth retaining method, comprising forming an earth retaining wall of 0.6 to 1.3 ton / m ³ and preventing collapse of surrounding ground when excavating an excavation area with the earth retaining wall. It is in. By adopting such a configuration, the ground improvement range by the retaining wall can be narrowed, and application on a narrow site without affecting the boundary of the adjacent land is possible. Also, since the ground improvement length can be shortened, the construction cost can be reduced.

[0007] A second aspect of the present invention is a non-reinforced wall-like body in which excavated soil, remaining soil other than excavated soil, a solidified material, and a lightweight material are mixed in the ground outside the excavated area. 0.
When a retaining wall of 6 to 1.3 tons / m ³ is formed, a steel material serving as a core is further disposed in the retaining wall, and a digging area is excavated with the retaining wall and the core. It is intended to provide an earth retaining method characterized by preventing collapse of a surrounding ground. By adopting such a configuration, in addition to the same effect as the above-described invention, the rigidity of the retaining wall is increased, and the applicable range is greatly expanded.

According to a third aspect of the present invention, a sheet pile is disposed on a front surface or a rear surface of the retaining wall.
It provides the described earth retaining method. By adopting such a configuration, in addition to achieving the same effects as the above-described invention, since the sheet pile serves as a water blocking wall, water intrusion into the excavation area is suppressed, work efficiency such as underground construction is improved, and safety is improved. Nature can be secured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An earth retaining method according to an embodiment of the present invention will be described below. In the present invention, the earth retaining wall formed in the ground outside the excavation area is an unreinforced wall-shaped body formed by mixing excavated soil, remaining soil other than excavated soil, solidified material, and lightweight material. And the unit volume weight 0.6 ~
It is 1.3 tons / m ³ .

The method for forming the retaining wall is not particularly limited. For example, a rod is rotated so that the tip of the mechanical stirring device is aligned with the core of the column to be installed, and the lightweight solidified material is discharged from the tip of the device. Rotating the stirring blade while mixing, excavating while mixing with the excavated soil, stopping discharge when reaching a predetermined depth, reversing the rod, pulling up on the ground with further mixing and stirring, the columnar body A mechanical stirring method for forming a wall-shaped earth retaining wall by connecting a large number of them, forming an insertion pipe provided with two injection nozzles in the vicinity of the tip portion into the ground, and rotating the injection nozzle to form a wall. A high-pressure cross jet jet method, in which a lightweight solidified material is injected from the individual injection nozzles to form a cross jet, a cylindrical object is formed, and a number of these are connected to form a wall-shaped retaining wall, Water from the lower nozzle The rod is rotated down while pouring, and when excavated to a predetermined depth, a lightweight solidified material is injected at a high pressure, and the rod is rotated up to form a columnar object. A continuous wall forming method using a high-pressure jet for forming an earth retaining wall is exemplified.

[0011] The lightweight solidified material used in the earth retaining method of the present invention is not particularly limited as long as it contains excavated soil and remaining soil other than excavated soil, solidified material and lightweight material.
For example, there is a soil in which a solidified material such as water and cement is mixed and fluidized with excavated soil or remaining soil other than excavated soil, and bubbles or foam beads are mixed to reduce the weight. The compounding amount of the solidified material and the lightweight material in the light-weight solidified material may be a compounding ratio such that the unit volume weight after forming the retaining wall is 0.6 to 1.3 ton / m ³ .

The form of the retaining wall formed by the above retaining wall forming method will be described with reference to FIGS. Figure 1
FIG. 4 is an explanatory view of an embodiment of the present invention, in which FIGS. 1 to 3 are schematic views of a vertical section of the ground, and FIG. 4 is a schematic view of a partial plane of FIG. FIG. 5 is an explanatory diagram of a conventional example compared with FIG. In FIG. 1, 1 is a retaining wall, 2
Is a final excavation surface, 3 to 6 are vertical pile rows formed from a large number of columnar piles, 21 is the ground, and A is an excavation area.

As shown in FIGS. 1 and 4, the retaining wall 1 has a columnar structure composed of a number of columnar piles. Vertical pile rows 3-6 and horizontal pile rows 31-37
Constitute a wall-shaped body that is continuously integrated with each other. Further, Kuicho of Tatekuiretsu 5,6 H _1, Kuicho of Tatekuiretsu 3,4 is H ₂ (<H _1), soil improvement range of earth retaining pile 1 W
_Is one. The retaining wall 1 is formed by compacting with a lightweight solidifying material, and has a unit volume weight of 0.6 to 1.3 ton / m ³ , preferably 0.6 to 1.2 ton / m ³ , More preferably, it is 0.8 to 1.2 tons / m ³ . In addition, when there is a groundwater level, it is preferably 1.0 to 1.3 ton / m ³ . The unit volume weight of the retaining wall refers to the density of the columnar structure, and the soil 17 of the ground interposed between the columnar piles in FIG. 4 is smaller than the entire columnar structure, and is included. The unit volume weight of the structure may be used.

The retaining wall using the lightweight solidifying material shown in FIGS. 1 and 4 has a unit volume weight of 1.6 to 1.... Of the conventional retaining wall 50 as compared with the conventional retaining wall 50 shown in FIG. 7 tons / m
^In contrast to ³ , the weight is 0.6 to 1.3 ton / m ³ and the weight is reduced by about 25 to 65%, so that an increase in lateral pressure due to its own weight can be suppressed. For this reason, the soil improvement range of the vertical pile rows 3 to 6 in FIG. 1 is W ₁ (< ₁ , compared to the ground improvement area W ₂ of the vertical pile rows 11 to 16 of the conventional retaining wall.
W ₂ ). In addition, it can be applied in a small site without invading the border of the adjacent land. Furthermore, since the pile length of the vertical pile row which is half of the retaining wall is as short as H ₂ (<H ₁ ), raw materials are reduced and construction efficiency is improved, so that cost can be reduced.

Next, the form of the retaining wall shown in FIG. 2 will be described. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted, and different points will be mainly described. That is, the difference from FIG. 1 is that a steel sheet 9a of sheet pile is arranged on the front face of the retaining wall 1, and furthermore, the steel sheet 9b of sheet pile is disposed on the back face of the other retaining wall 1 opposite to the retaining wall 1.
It is in the point where is arranged. The installation form of the sheet pile is not limited to this form, and the sheet pile 9a and the sheet pile 9b are both installed on the front surface of the retaining wall 1, and the sheet pile 9a and the sheet pile 9b are both installed on the back surface of the retaining wall 1. The form or the form in which the sheet pile is installed on both the front and back of the retaining wall may be used. By installing sheet piles on the back of the retaining wall 1, the ground 2
1 can be prevented from entering the retaining wall 1.

Next, the form of the retaining wall shown in FIG. 3 will be described. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted, and different points will be mainly described. That is, what differs from FIG. 1 is that the core material 10 is installed in the retaining wall 1. Examples of the core material 10 include H steel. Installation of the core member 10 may be performed by selecting appropriately the number and location of the core material suitable for a desired intensity level. By installing this core material, the retaining wall 1
The stiffness further increases.

In the present invention, the wall-shaped form of the retaining wall is not limited to the above-described embodiment, and in addition, for example, in the case of a column structure including a large number of column-shaped piles, the overlapping of the column-shaped piles The portion may be formed only in the left-right direction and may be in a form in which the front-rear direction is in contact, or may be a wall-shaped form other than the columnar structure. Accordingly, the vertical cross-sectional shape of the retaining wall is not particularly limited. For example, in the case of a columnar structure including a large number of columnar piles, in addition to the above-described embodiment, the pile length is conventionally reduced only by reducing the number of piles. It may be the same as the example, or the form may be such that the pile length is shortened for each row sequentially from the front of the retaining wall, and the tip of the pile length forms an inclined surface.

[0018]

According to the first aspect, the range of the ground improvement by the earth retaining wall can be narrowed, and it is possible to apply the present invention in a narrow site without invading the boundary of the adjacent land. In addition, since the ground pile length can be shortened, raw materials can be reduced and workability can be improved, so that significant cost reduction can be achieved.

According to the second aspect, in addition to the same effect as the above-mentioned invention, the rigidity of the retaining wall is increased, and the applicable range is greatly expanded. According to the third aspect, in addition to having the same effect as the above invention, since the sheet pile serves as a water stop wall, intrusion of water into the excavation area can be prevented, work efficiency such as underground construction is improved, and Safety can be ensured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vertical section of a ground according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a vertical section of a ground according to another embodiment of the present invention.

FIG. 3 is a schematic diagram of a vertical section of a ground according to another embodiment of the present invention.

FIG. 4 is a schematic plan view of a part of FIG. 1;

FIG. 5 is a schematic diagram of a vertical section of a conventional ground compared with FIG. 1;

[Explanation of symbols]

1,50 Earth retaining wall 2 Final excavation surface 3-6,11-16 Vertical pile row 9a, 9b Sheet pile 10 Core material 17 Soil interposed in columnar pile 18 Overlapping part 21 Ground 31-37 Horizontal pile row A Excavation area H ₁ , H ₂ pile length W ₁ , W ₂ ground improvement area

Claims (3)

[Claims] An unreinforced wall-shaped body in which excavated soil, remaining soil other than excavated soil, a solidified material, and a lightweight material are mixed in the ground outside the excavated area, and has a unit volume weight of 0.6 to 1%. .3 tons /
An earth retaining method comprising forming an earth retaining wall of m ³ and preventing collapse of a surrounding ground when excavating an excavation area with the earth retaining wall. 2. An unreinforced wall-like body in which excavated soil, remaining soil other than excavated soil, a solidified material and a lightweight material are mixed in the ground outside the excavated area, and having a unit volume weight of 0.6 to 1 .3 tons /
An earth retaining wall of m ³ is formed, and a steel material serving as a core is further disposed in the earth retaining wall to prevent collapse of a surrounding ground when excavating an excavation area with the earth retaining wall and the core. An earth retaining method characterized by the following. 3. The earth retaining method according to claim 1, wherein a sheet pile is disposed on a front surface or a rear surface of the earth retaining wall.