JP2008303583A - Structure of artificial ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent horizontal displacement of a sideways flow or the like by stably supporting a structure in soft natural ground using simple artificial ground without a pile, and stabilizing the natural ground. <P>SOLUTION: A floor slab 2 for supporting the structure 1 and a soil improvement body 13 for supporting the floor slab are constructed on the soft natural ground 3, a core material 11 is integrally fixed on the upside of the soil improvement body, the upper part of the core material is projected in the floor slab and fixed, and the soil improvement body and the floor slab are connected to each other through the core material. The soil improvement body is constructed like a grid by arranging a number of soil improvement piles 10 vertically and horizontally in a plan view, the core material 11 is fixed to the upper part of the soil improvement pile located in the intersection of the grids, and the upper parts of the core materials are connected to each other by a tension member 14. Another soil improvement pile 15 is constructed also in a cell of the grid-like soil improvement body. The upper part of the soil improvement body is supported by a batter pile made of the soil improvement pile. The soil improvement body 13 is extended not only to the floor slab, but also to the lower side of an overlaid ground such as a banking 6 constructed in the periphery thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention mainly solves problems such as stabilization of the soft ground and lateral flow caused by the presence of embankment etc. on one side when building a structure such as a retaining wall or abutment on the soft ground. It relates to the structure of artificial ground.

As shown in FIG. 6, when a structure 1 such as a retaining wall or an abutment is constructed on the original ground 3, if the original ground 3 is a soft ground or a liquefied ground, a lateral flow occurs on the original ground 3. Therefore, there is a concern that lateral displacement and uneven settlement of the structure 1 may occur, so that the pile 5 is usually provided so as to reach the stable support layer 4 and the foundation 1a of the structure 1 is supported by the pile 5. It is common.
Further, as shown in the figure, when the embankment 6 is formed behind the structure 1 (or when the original ground 3 is left as the upper ground as it is behind the structure 1), as shown in FIG. By constructing a ground improvement body 7 by a ground improvement technique such as a deep mixing treatment method in the original ground 3 below the embankment 6, it supports the upper load due to the embankment 6 and the upper ground and strengthens the original ground 3 side. It is also carried out to prevent the occurrence of side flow.

In addition, for example, those disclosed in Patent Documents 1 to 4 are known as a reinforcing technique when embankment is created on soft ground or liquefied ground.
The embankment reinforcement structure disclosed in Patent Document 1 is to continuously install sheet pile walls inside the embankment.
The liquefaction countermeasure method for the embankment structure shown in Patent Document 2 is to construct a continuous underground wall at the bottom edge of both sides of the embankment, and connect the heads of both continuous underground walls with tie rods, The head of the continuous underground wall is supported by an earth anchor.
The liquefaction prevention structure shown in Patent Document 3 is to form a solidified block by ground improvement along the outer periphery of the foundation of an existing structure, and to place a steel pipe sheet pile on the solidified block.
The ground improvement body and the ground improvement construction method disclosed in Patent Document 4 are to embed a concrete column body having higher compressive strength as a core material in a soil cement column formed by ground improvement.
JP 2003-13451 A Japanese Patent Laid-Open No. 11-1926 JP 2005-200870 A JP 2003-55956 A

As shown in FIGS. 6 and 7, supporting the structure 1 with the pile 5 requires a large number of piles 5 having a large cross section, and it is sufficient to simply build the ground improvement body 7 in the original ground 3. The improvement rate for obtaining the effect of preventing lateral flow is greatly increased, neither of which is reasonable.
Moreover, reinforcement by a sheet pile wall as shown in Patent Document 1, reinforcement by a continuous underground wall as shown in Patent Document 2, a liquefaction prevention structure shown in Patent Document 3, and ground improvement shown in Patent Document 4 All of the bodies require large-scale construction and are expensive to construct, and have not been widely spread because the scope of application is limited.

  In view of the above circumstances, in the case of constructing a structure such as a retaining wall or an abutment on a soft ground, the present invention may provide stabilization of the soft ground or lateral flow caused by the presence of embankment or the like on one side thereof. An object of the present invention is to provide an effective artificial ground structure that can solve the problem.

  The present invention relates to a structure of an artificial ground provided on a raw ground to support the structure when constructing a structure such as a retaining wall or an abutment on the soft raw ground, and the raw ground to support the structure A floor slab constructed above, and a ground improvement body built in the original ground to support the floor slab, and a core material is integrally fixed to the upper portion of the ground improvement body, and the upper portion of the core material is The ground improvement body and the floor slab are combined with each other through the core by protruding and fixing in the floor slab.

In the present invention, a plurality of ground improvement bodies that support the floor slab are arranged in a plan view vertically and horizontally, a core material is fixed to the upper part of the ground improvement body, and the upper parts of the core material are assumed to be structures. It is good to connect with the tension | tensile_strength material arrange | positioned along the horizontal displacement direction.
Alternatively, a ground improvement body for supporting the floor slab is constructed by arranging a large number of ground improvement piles vertically and horizontally in plan view and building in a lattice shape, and the core material is located above the ground improvement pile located at the intersection of the lattices It is preferable that the upper portions of the core members are connected to each other by at least a tensile member disposed along the assumed horizontal displacement direction of the structure.
Moreover, you may build another ground improvement body in the grid of the grid-like ground improvement body which supports a floor slab.
It is also conceivable to construct a slope pile made of a ground improvement pile on the outside or inside of the ground improvement body that supports the floor slab, and to support the upper part of the ground improvement body by the slope pile.
Furthermore, the ground improvement body that supports the floor slab may be extended to the lower part of the upper ground such as embankment formed around the floor slab, and the floor slab and the upper ground may be supported by the ground improvement body.

According to the present invention, the core material is fixed to the upper portion of the ground improvement body supporting the floor slab, and the upper portion of the core material is fixed to the floor slab, so that the floor slab and the ground improvement body are interposed via the core material. As a result, the floor slab and the structure supported by it can be stably supported by the ground improvement body without the need for piles as in the past, and the water slab movement of the floor slab with respect to the original ground is ensured. Can be restrained.
In addition, it can be expected that the core material functions as a bending reinforcement and a shear reinforcement for the upper part of the ground improvement body, so that the lateral displacement and bending deformation of the ground improvement body can be effectively restrained, and the level of the original ground An excellent prevention effect against displacement can be obtained.

In particular, a large number of ground improvement piles are arranged vertically and horizontally in plan view to construct a grid-like ground improvement body, and the upper parts of the various ground improvement piles are connected by a tensile material via a core material, so that the whole Sufficiently high rigidity, the lateral displacement and bending deformation are reliably restrained, and an excellent horizontal displacement prevention effect is obtained by the cooperation of the ground improvement body, the core material, and the tensile material.
Moreover, the whole ground improvement body can be made more rigid by providing another ground improvement body also in the grid | lattice of a grid | lattice-like ground improvement body, or providing a diagonal pile in the outer side and inner side of a ground improvement body.
Furthermore, the ground improvement body that supports the floor slab is extended to the periphery, and the upper ground such as embankments created around the floor slab is also supported by the ground improvement body, so that not only the floor slab but also the surrounding ground above it is supported. Can be supported stably, and a superior horizontal displacement prevention effect can be obtained.

  A first embodiment of the present invention is shown in FIG. As shown in the examples shown in FIGS. 6 and 7, the structure 1 such as a retaining wall or an abutment is constructed on the soft ground 3 and the embankment as an overlay ground on the ground 3 is located behind the structure 1. 6 is an application example in which a reinforced concrete floor slab 2 for supporting the structure 1 is provided on the original ground 3, and the floor slab 2 is placed in the original ground 3 below the floor slab 2. The ground improvement pile 10 for supporting the structure 1 is constructed so as to reach the stable support layer 4, and the structure 1 is supported by a simple artificial ground composed of the floor slab 2 and the ground improvement body 10, and the original It is intended to prevent horizontal displacement such as lateral flow from occurring in the ground 3.

The ground improvement pile 10 has a circular cross section built locally by a well-known ground improvement method such as a deep mixing treatment method, and is arranged at predetermined intervals in the length direction and the front-rear direction of the floor slab 2 in the illustrated example. Provided independently.
And the short core material 11 which consists of steel materials, such as H-shaped steel or a steel pipe, is inserted in the upper part of each ground improvement pile 10, and the upper part of these core materials 11 is the ground improvement pile 10's upper part. By projecting from the upper end and being inserted into the floor slab 2 and being fixed thereto, the core members 11 are connected to each other via reinforcing bars 12 arranged in the floor slab 2. .
The core material 11 preferably has a desired tensile strength, bending rigidity, and shear rigidity, and a steel material can be suitably used. Moreover, in order to ensure the integrated strength of the core material 11 with respect to the ground improvement pile 10 and the floor slab 2, an appropriate fixing force enhancing means such as a stud or a protrusion may be provided on the core material 11, and in that case For the core material 11, a flexible material such as a wire can be used.

In the first embodiment, the core material 11 is fixed to the upper part of the ground improvement pile 10 and the upper part of the core material 11 is fixed to the floor slab 2, so that the floor slab 2 and the ground improvement pile 10 are connected to each other. Therefore, the ground structure piles 10 and the floor slab 2 can stably support the structure 1 in a stable manner, and the water slab of the floor slab 2 with respect to the original ground 3 can be stably supported. Is surely restrained.
In particular, the upper part of the ground improvement pile 10 is structurally connected to each other via the core material 11 and the floor slab 2, and the core material 11 also functions as a bending reinforcement material and a shear reinforcement material for the upper part of the ground improvement pile 10. Therefore, the entire structure is sufficiently rigid to effectively restrain lateral displacement and bending deformation.
Therefore, in the structure of the first embodiment, as shown in FIGS. 6 to 7, it is easy to use the ground improvement pile 10 and the floor slab 2 without providing the pile 5 having a large cross section for supporting the structure 1. By providing a simple artificial ground, sufficient supporting force for the structure 1 and excellent horizontal deformation prevention effect can be obtained, and particularly the lateral displacement and non-uniform settlement of the structure 1 due to lateral flow can be surely prevented. It is what you get.
In addition, in order to effectively obtain the reinforcing function by the core material 11 for the ground improvement pile 10 as described above, the core material 11 is installed in a range where the tensile stress is particularly generated in the upper part of the ground improvement pile 10. What is necessary is just to set length, intensity | strength, and a number so that a desired reinforcement effect may be acquired. As an example, the insertion length of the core material 11 is calculated by calculating the characteristic value β of the ground improvement body 10 in a range considered as a unit, and 1 / β downward from the head of the ground improvement body 10 based on the β. It is conceivable to set the value to be in the range of ~ 1.5 / β.

FIG. 2 shows a second embodiment. This is because a large number of ground improvement piles 10 are continuously arranged in the vertical and horizontal directions in plan view to build a lattice-like ground improvement body 13 and the core is placed at the upper part of the ground improvement pile 10 located at the intersection of the lattices. The material 11 is fixed, and the upper parts of the core material 11 are inserted into the floor slab 2 to be fixed, and the upper parts of the core material 11 are connected to each other under the floor slab 2 by the tensile material 14 arranged vertically and horizontally. is there.
As the tensile material 14, a bar or wire made of a material having a desired tensile strength, for example, a steel frame or steel material having a small cross section, a reinforcing bar or a PC steel wire, or a geotextile or rope made of high-strength fiber can be suitably used. Yes, if necessary, treatment such as rust prevention to ensure durability may be performed.
The tension members 14 are preferably arranged in a grid pattern vertically and horizontally as in the illustrated example, but at least a direction in which horizontal displacement such as lateral flow is expected to occur significantly (generally the length of the structure 1). The tensile material 14 in the longitudinal direction of the structure 1 can be omitted. Of course, the meaning of “along the direction in which the horizontal displacement is expected to occur significantly” is not limited to “parallel” to the direction, and within the range in which an equivalent effect can be obtained, Naturally, it may be slanted.

According to the structure of the second embodiment, the ground improvement body 13 and the floor slab 2 are coupled via the core material 11 in the same manner as in the first embodiment. The load of the structure 1 is stably supported, the water smooth movement of the floor slab 2 is restricted, and horizontal displacement such as lateral flow can be effectively prevented.
In particular, in the second embodiment, the ground improvement body 13 is constructed in a lattice shape, and the upper portions of the ground improvement piles 10 constituting the lattice-like ground improvement body 13 are connected by a tensile material 14. Therefore, the entire structure is sufficiently high in rigidity, and lateral displacement and bending deformation are surely restrained. Therefore, excellent horizontal operation is achieved by the cooperation of the grid-like ground improvement body 13 with the core material 11 and the tension material 14. A direction displacement preventing effect is obtained.

FIG. 3 shows a third embodiment. This is a further enhancement of the grid-like ground improvement body 13 in the second embodiment.
That is, in the third embodiment, as in the second embodiment, not only a large number of ground improvement piles 10 are integrally arranged vertically and horizontally to build a lattice-like ground improvement body 13, but also as shown in (c). In addition, the ground improvement body 13 is constructed almost entirely below the floor slab 2 by constructing another ground improvement pile 15 in the grid.
In this case, the ground improvement pile 15 built in the grid may reach the support layer 4 similarly to the ground improvement pile 10, but the ground improvement pile 15 is replaced with a short pile as shown in (b). As shown in (d), it may be provided in the form of a horizontal connection pile at a desired depth (for example, near the tip of the core material 11) as shown in FIG. The integrated strength of the entire ground improvement body 13 can be sufficiently increased to enhance the horizontal displacement prevention effect.

FIG. 4 shows a fourth embodiment. This is based on the third embodiment, but is constructed by extending the ground improvement body 13 to the lower side of the embankment 6 so that not only the load of the structure 1 but also the upper load of the embankment 6 is ground. It is intended to be supported by the improved body 13, thereby obtaining a further excellent horizontal displacement prevention effect.
In this case, the ground improvement body 13 may be formed in a lattice shape with the same pitch as the lower portion of the floor slab 2 below the embankment 6, but the embankment as shown in FIG. Below 6, the grid grid size can be changed. Further, as shown in the illustrated example, another ground improvement pile 15 may be provided in the grid even below the embankment 6, but it may be omitted depending on the overlay load of the embankment 6.

  FIG. 5 shows a fifth embodiment. This is based on the fourth embodiment and is provided with oblique piles 16 made of ground improvement piles outside and inside the ground improvement body 13. The slant pile 16 is a ground improvement pile built in an inclined state, and its upper portion is provided close to or joined to the upper portion of the ground improvement pile 10 constituting the ground improvement body 13, thereby improving the ground. The horizontal force caused by the lateral flow pressure received by the body 13 can be effectively resisted by the compressive strength of the inclined pile 16.

Although the embodiment of the present invention has been described above, the gist of the present invention is to support a structure provided on the soft ground by a simple floor slab and an artificial ground by a ground improvement body without using a pile. The core material may be fixed to the upper part of the ground improvement body that supports the plate and the upper part may be fixed to the floor slab, and as long as the present invention is combined with each of the above-described embodiments, various design features Needless to say, changes and applications are possible.
For example, the floor slab 2 is realistically made of reinforced concrete or unreinforced concrete, but in addition to this, it is formed by mixing and stirring a hardener to earth and sand if it is within a range where necessary strength can be obtained. It may be. In the first embodiment, the reinforcing bars 12 arranged in the reinforced concrete floor slab 2 serve to connect the cores 11 arranged in the ground improvement piles 10, so that a tensile material is particularly arranged. However, a tensile member for connecting the core members 11 may be disposed in the floor slab 2 along the assumed horizontal displacement direction of the structure.

It is a figure which shows 1st Embodiment of the structure of the artificial ground of this invention. It is a figure which shows 2nd Embodiment same as the above. It is a figure which shows 3rd Embodiment same as the above. It is a figure which shows 4th Embodiment. It is a figure which shows 5th Embodiment as well. It is a figure which shows an example of the structure of the structure by the conventional common pile. It is a figure which shows an example of the reinforcement method with respect to the conventional general soft ground.

Explanation of symbols

1 Structure 2 Floor slab 3 Original ground (soft ground)
4 Support layer 6 Embankment (overlaying ground)
10 Ground improvement pile (Ground improvement body)
11 Core material (steel material)
12 Reinforcing Bars 13 Ground Improvement Body 14 Tensile Material 15 Ground Improvement Pile (Ground Improvement Body)
16 Diagonal pile (ground improvement pile)

Claims (6)

When constructing a structure such as a retaining wall or an abutment on a soft original ground, the structure of the artificial ground provided on the original ground to support the structure,
A floor slab constructed on the original ground to support the structure, and a ground improvement body created in the original ground to support the floor slab,
By fixing the core material integrally to the upper part of the ground improvement body and projecting and fixing the upper part of the core material into the floor slab, the ground improvement body and the floor slab are coupled via the core material. The structure of artificial ground characterized by The artificial ground structure according to claim 1,
A plurality of ground improvement bodies that support the floor slab are arranged vertically and horizontally in plan view, and a core material is fixed to the upper part of the ground improvement body, and the upper parts of the core material are aligned with each other along the assumed horizontal displacement direction of the structure. The structure of the artificial ground characterized by connecting with the tension | tensile_strength material arrange | positioned. The artificial ground structure according to claim 1,
A large number of ground improvement piles are arranged vertically and horizontally in a plan view to build a ground improvement body to support the floor slab, and a core material is fixed to the upper part of the ground improvement pile located at the intersection of the lattices. And the structure of the artificial ground characterized by connecting the upper part of this core material with the tension | tensile_strength material arrange | positioned along the horizontal displacement direction which the structure is assumed at least. The structure of the artificial ground according to claim 3, wherein another ground improvement body is built in a grid of the grid-like ground improvement body that supports the floor slab. The artificial ground structure according to any one of claims 1 to 4, wherein a slope pile comprising a ground improvement pile is built outside or inside a ground improvement body supporting a floor slab, and the ground improvement body is formed by the slope pile. An artificial ground structure characterized by supporting the upper part of the ground. The artificial ground structure according to any one of claims 1 to 5,
The ground improvement body that supports the floor slab is constructed by extending to the lower part of the upper ground such as embankment created around the floor slab, and the ground improvement body supports the floor slab and the upper ground. The structure of the artificial ground.

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