JP2011026792A - Structure and construction method of reinforced soil banking - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide reinforced soil banking that can secure flexibility of reinforced soil and transmit the horizontal and vertical load of the reinforced soil surely to support piles. <P>SOLUTION: The reinforced soil banking A is constructed by alternately arranging fiber reinforced materials 1 laid in a plane, and banking layers 2 filled in the substantially same thickness on the fiber reinforced materials 1. The support piles 3 driven in a vertical direction are arranged inside the reinforced soil banking A. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a structure and construction method of a reinforced earth embankment.

In recent years, embankment (reinforcement soil) constructed by arranging reinforcing materials such as fibers that are inexpensive and excellent in workability is often used for earthquake countermeasures and rockfall countermeasures for embankments.
However, in places where the installation space for structures is not sufficiently secured such as on slopes, the bottom width of the reinforced soil directly based on the foundation cannot be taken sufficiently, and horizontal and vertical support force cannot be obtained. It has been difficult to use reasonable reinforced soil.
As a conventional technique in such a case, an expensive measure such as constructing a pier that also serves as a large-scale pile driving and a construction road on a slope and driving a long pile is planned.
In addition, there are many cases where the countermeasures are postponed because the countermeasures according to the prior art are expensive. As a result, the embankment on the slope collapses every time an earthquake occurs, which is becoming a major social problem.
Therefore, it is desired to develop a technique for obtaining horizontal and vertical supporting force of reinforced soil that is inexpensive and excellent in workability even at a site where the bottom surface width cannot be sufficiently obtained.
In addition, if horizontal supporting force is secured with thin reinforcing soil whose bottom width is not sufficient, there is a risk of breaking inside the reinforcing soil, so it is necessary to secure horizontal and vertical supporting force in the narrow reinforcing soil. In technology development, technology development for ensuring flexibility is also required.

JP 2004-218263 A

The above-mentioned press embankment is relatively inexpensive and highly effective, but has the following problems.
<1> Space is required to secure the installation space, but it is often not possible to remove it on existing embankments or slopes.
<2> Excavation may be necessary, but large excavation is required.
<3> Even if it can be installed, it cannot secure a supporting force that resists backside earth pressure.

  In order to solve the above-described problems, the embankment structure of the present invention is configured by alternately arranging a fiber reinforcing material laid in a plane and an embankment layer erected with substantially the same thickness on the fiber reinforcing material. The reinforced earth embankment is characterized in that a support pile driven in the vertical direction is arranged inside the reinforced earth embankment.

Moreover, the construction method of the reinforced earth embankment of this invention installs a support pile in the construction planned site | part of a reinforcement earth embankment, lays a fiber reinforcement material planarly around this support pile, and on the fiber reinforcement material. In the state of surrounding the support pile, the embankment layer is raised with substantially the same thickness, and this operation is alternately performed and constructed.

Since the embankment structure and construction method of the present invention are as described above, at least one of the following effects can be obtained.
<1> A major feature of the present invention is that the pile and the reinforcing soil are integrated to obtain horizontal and vertical supporting force, and at the same time, the flexibility of the reinforcing soil is ensured. Therefore, it is the structure which resists with the rigidity of a support pile with respect to the horizontal force by the earth pressure of collapsed earth and sand.
<2> While laying reinforcing materials such as fibers in a horizontal plane in the form of taking in the pile heads of piles installed on the ground, while laying reinforcing materials such as fibers along the side of the pile extending direction in the pile, Since the reinforced soil is constructed by embankment, the horizontal and vertical loads of the reinforced soil can be reliably transmitted to the pile, and the flexibility of the reinforced soil can be ensured by embedding the pile in the reinforced soil. These effects have been confirmed by dynamic centrifugal model experiments.
<3> Since it is supported by piles, the horizontal and vertical supporting force of the reinforced soil can be obtained even at a site where the bottom surface width is not sufficient.
<4> Since the conventional reinforced soil resists a horizontal force by the frictional resistance of the bottom surface, a wide bottom board width is required. However, in the present invention, since it is supported by a pile, the width can be narrowed.
<5> When horizontal supporting force is secured with a thin reinforcing soil with a sufficient bottom width, sufficient flexibility can be secured without breaking inside the reinforcing soil. <6> As on a slope Even in places where the installation space for the structure cannot be sufficiently secured, it is possible to install reinforcing soil constructed by arranging reinforcing materials such as fibers that are inexpensive and have excellent workability. As a result, it is possible to contribute to the spread of embankment measures on slopes that have been prone to be postponed until now because the conventional technology is expensive.
<7> Since it is reinforced by the support pile, the ground reaction force is smaller than before with respect to the vertical load of the reinforced soil.
<8> Although it can be applied to any place or scale of structure, it can be expected to have a greater economic effect especially at sites such as banking measures on slopes where it is difficult to secure construction sites.

Explanatory drawing of the Example of the structure of the embankment of this invention. Explanatory drawing of the other Example of the structure of embankment. Explanatory drawing of the Example of the construction method of a banking. Explanatory drawing of the installation state of embankment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

<1> Overall configuration.
The present invention is a reinforced earth embankment in which fiber reinforcing materials 1 laid in a plane and embankment layers 2 erected at substantially the same thickness on the fiber reinforcing material 1 are alternately arranged, and the reinforcing soil A support pile 3 driven in the vertical direction is arranged inside the embankment.
Thus, the pile head of the support pile 3 installed in the ground is characterized by the structure embedded in the reinforced earth embankment A.
In this case, the embankment is an embankment constructed by wrapping earth and sand with the fiber reinforcing material 1, that is, a reinforced earth body.
In this way, the reinforcing material embankment A is constructed by embedding the reinforcing material 1 such as fibers in a plane in a form of taking in the pile head of the support pile 3 installed on the ground, and as a result, The horizontal supporting force and flexibility, as well as the vertical supporting force can be increased.

<2> Fiber reinforcing material.
First, the geotextile will be described as the fiber reinforcement 1 that forms the reinforced earth embankment A.
The geotextile here refers to a geogrid, a geonet, or a geotextile-related product in addition to the geotextile defined in JIS L0221.
Non-woven fabrics, woven fabrics, knitted fabrics, geogrids, geonets, composite products, and the like are commercially available as product forms, but detailed explanations are omitted, but these commercially available products can be widely adopted.

<3> A shape retaining frame.
In order to hold the shape of the front surface of the embankment, the shape holding frame 4 is used.
The shape retaining frame 4 is formed by a rising portion and a horizontal portion by bending a net material formed in a lattice shape with a metal material into an L shape.
Examples of the mesh material forming the shape retaining frame 4 include an expanded metal and a welded wire mesh formed in a net shape by welding.
Moreover, it is preferable that the above metal material has a countermeasure against corrosion.
A vegetation sheet or a vegetation mat may be attached to the rear side of the rising portion of the shape retaining frame 4 for the front greening of the reinforced earth embankment A.
Examples of the vegetation sheet include non-woven fabrics, paper, and sheet materials using natural materials that are seeded.
As the vegetation mat, for example, a non-woven fabric, paper, a mat using a natural material, or the like is processed into a cylindrical shape, and soil, fertilizer, and seeds are contained inside the cylindrical shape.

<4> Support pile.
The support pile 3 used for this construction method uses, for example, steel H-shaped steel.
Although it is not particularly limited to the shape, it is easy to adopt H-shaped steel on site such as banking measures on slopes where it is difficult to secure a construction site because it can be placed relatively easily.
Furthermore, since the load above the slope is resisted by the reinforced earth embankment A, a simple support pile 3 such as an H-shaped steel that is relatively short and not so rigid can be used.
Thus, since the long and rigid support pile 3 generally used for slope failure prevention etc. is unnecessary, a simple thing is sufficient for the pier and heavy machinery accompanying the placement of the support pile 3, and a carrying in / out path.

<5> Fill material.
As the embankment material constituting the reinforced embankment A, general earth and sand can be adopted.
In particular, when constructing reinforced soil as a measure for embankment on slopes, it can be constructed using excavated soil from existing embankments, so in this respect as well, it is possible to reduce the removal of residual soil and the construction materials. It becomes possible to secure a higher economy.

<6> Construction method.
Next, the banking construction method of the present invention will be described.

<7> Placing support piles.
First, a flat area with a certain area is created on the foundation of the embankment.
When embankment is formed on a part of the slope, a part of the slope is excavated horizontally to create a flat part.
Support piles 3 are placed at predetermined positions on this plane portion with a gap.
At the stage of placing the support pile 3, nothing is arranged on the plane portion, so the placing work is easy.

<8> Installation of a shape retaining frame.
The shape retaining frame 4 is placed side by side along the same plane on the front surface of the planned position where the reinforced soil is embanked.
When the shape holding frames 4 are arranged, the rising portion of the shape holding frame 4 having an L-shaped cross section is positioned on the front surface of each layer of the reinforcing soil.
At the same time, the horizontal portion of the shape retaining frame 4 having an L-shaped cross section is buried and positioned between every layer of reinforcing soil.
As a result, the plurality of shape retaining frames 4 are installed such that the rising portions form one row in the horizontal direction, and the horizontal portions of the shape retaining frames 4 are arranged substantially in a plane along each layer of the reinforcing soil. Yes.
As described later, when the reinforced earth embankment layers are stacked, the shape holding frames 4 on the upper and lower stages can be arranged in a staggered manner for each stage without being arranged in a vertical line in the vertical direction.

<8> Laying fiber reinforcement.
A fiber reinforcing material 1, for example, one side edge of the geotextile is connected and fixed to the rear portion of each row of the shape holding frames 4 arranged in the substantially horizontal direction.
If the width of each shape holding frame 4 and the width of the belt-shaped fiber reinforcing material 1 are configured to be the same, each shape holding frame 4 is provided with one fiber reinforcing material 1 and the depth of the reinforced earth embankment A. Can be laid in the direction.
When constructing the reinforced earth embankment at the hem of the slope, the length of the fiber reinforcing material 1 to be laid is set to a length such that the tail end is in contact with the slope.
The front end of the fiber reinforcing material 1 is set to a dimension longer than the position of the shape holding frame 4, and the excess length portion is folded back.
At the time of laying the fiber reinforcing material 1, the support pile 3 is already placed on the flat surface, but since the support pile 3 is arranged in a dot shape, the fiber reinforcing material 1 is cut and the support pile 3 is attached. It is easy to avoid and lay the fiber reinforcement 1.
Alternatively, if the placement position of the support pile 3 is determined based on the allocation of the fiber reinforcement 1 to be laid, the support pile 3 is positioned between the fiber reinforcement 1 and the fiber reinforcement 1 as shown in the figure. be able to.
The laying length of the reinforced earth embankment A of the fiber reinforcing material 1 in the depth direction (front-rear direction) is that the reinforced earth wall structure 11 resists the earth pressure from the slope by its own weight, and has a stable leaning type. The length is set so as to satisfy the mass weight necessary for the stability as a leaning retaining wall to be constructed as a wall.

<9> Sedimentation of earth and sand.
In this way, a plurality of shape holding frames 4 are arranged in a horizontal row on the front surface of the reinforced earth embankment A, and the fiber reinforcement 1 is arranged in the depth direction of the reinforced earth embankment A on the back surface of each shape holding frame 4.
After that, one embankment material is rolled out to a predetermined thickness from the back side of the shape retaining frame 4 to the upper surface between the fiber reinforcements 1 with a backhoe or the like to construct one embankment layer.
Then, the embankment material is compacted by using a compacting machine such as a vibration compactor or a vibration roller.
Although the support pile 3 is established in the area where the earth and sand is squeezed out, the position of the support pile 3 is a point in the plan view, so that it does not become an obstacle to the scouring and rolling of the earth and sand.

<10> Encasement of earth and sand.
When the extra length portion of the fiber reinforcing material 1 that has been folded back on the shape retaining frame 4 is returned to the reinforced earth embankment side, the extra length portion wraps the end of one embankment layer.
As a result, the front end of one layer of each embankment is wrapped with the fiber reinforcing material 1, and the shape holding frame 4 is positioned on the outer side to maintain the shape.

<11> Stack up.
Subsequently, in the same process as described above, the shape holding frame 4 is installed on the end portion of the one-layer embankment layer 2, and the fiber reinforcing material 1 connected to the shape holding frame 4 is laid.
The embankment material is unwound on the fiber reinforcing material 1 and the surface thereof is rolled.
The thickness of one layer, that is, the interval between the fiber reinforcements 1 is, for example, about 0.1 to 1.2 m.
Thus, by repeating the above steps to the designed height, the reinforced earth embankment A in which the fiber reinforcing material 1 is laid and the support pile 3 is positioned inside is completed.

<12> Another embodiment (FIG. 2)
Said Example was the structure which locates the support pile 3 in the inside of a banking body independently.
However, in order to further improve the integrity of the support pile 3 and the reinforced earth embankment A, a configuration in which the inter-pile curtain 5 is arranged in a screen shape between the support piles 3 can be adopted.
The same material as the fiber reinforcing material 1 can be used for the pile curtain 5.
In that case, the inter-pile curtain 5 does not expand over the entire height of the support pile 3 at a time, but expands by the thickness of one layer to be raised.
If piles of sand and sand are piled up and rolled on both sides of the inter-pile curtain 5, the inter-pile curtain 5 does not become an obstacle to the construction of the reinforced earth embankment A.
The pile curtain 5 and the support pile 3 may be attached together by a steel wire or the like.

1: Fiber reinforcement 2: Filling layer 3: Support pile 4: Shape retaining frame 5: Pile curtain

Claims (4)

A fiber reinforcement laid in a plane,
Reinforced earth embankment in which the embankment layers raised with almost the same thickness are arranged alternately on the fiber reinforcement,
Inside the reinforced earth embankment,
Support piles driven in the vertical direction are arranged.
Structure of reinforced earth embankment.
Placing a curtain between the support piles like a screen,
The structure of the reinforced earth embankment according to claim 1.
Support piles are installed in the planned construction site of the reinforced earth embankment,
A fiber reinforcing material is laid flat around the support pile,
On the fiber reinforcement, in a state of surrounding the support pile, the embankment layer is raised with almost the same thickness,
Build this work alternately,
Construction method of reinforced earth embankment.
Placing a curtain between the support piles like a screen,
The construction method of the reinforced earth embankment of Claim 3.

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