JP2005139807A - Foundation pile and foundation structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the most of each feature of a foundation pile composed of a prefabricated pile body and the foundation pile composed of a soil improvement body, and to mutually compensate for each problem. <P>SOLUTION: The foundation piles 1 have supporters 3 consolidated by injecting a connecting substance into a ground and composed of the soil improvement body and the prefabricated pile bodies 4 buried in the ground under the state in which the front end sides are supported to the supporters 3. The pile bodies 4 are connected to the supporters 3 by inserting the front end sides into the supporters 3 before the supporters 3 are cured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a foundation pile having a ready-made pile body such as a steel pipe and a cast iron pipe.

  First, as a conventional foundation pile, a torsion steel pipe pile 51 described in Patent Document 1 is exemplified. As shown in FIG. 8, the steel pipe pile 51 has a plurality of propeller blade-shaped cutting blades 53a, 53b, 53c that are cut into the ground at an acute angle on the outer periphery of the steel pipe 52 along the spiral trajectory. These cutting blades 53a, 53b, 53c are provided at an appropriate interval so as to allow passage of obstacles such as glass and scrap.

  Further, as another foundation pile, a soil cement composite outer shell steel pipe concrete pile 61 described in Patent Document 2 is exemplified. As shown in FIG. 9, the concrete pile 61 is formed by inserting an outer shell steel pipe concrete pile 64 having a spiral or disc-shaped steel blade 63 into a soil cement column 62.

JP 2002-105953 A JP 2001-303561 A

  However, since the steel pipe pile 51 described in Patent Document 1 is screwed into the ground and penetrates, (a) the tip is easily consumed and corroded, (b) due to the presence of obstacles in the ground, There is a problem that twisting becomes difficult. Moreover, since the pile diameter is small compared with the pile body which consists of soil cement by a deep mixing process method, there also exists a subject that a surrounding surface friction force is small and a supporting force is weak.

  According to the concrete pile 61 described in Patent Document 2, a soil cement column 62 is formed by stirring and mixing the ground and an additive containing a cement-based curing agent by a deep mixing method, and the soil cement column 62 is cured. Since the outer steel pipe concrete pile 64 penetrates into the ground before, the said subject in patent document 1 does not arise easily. However, in order to form the soil cement pillar 62 from the support layer to the vicinity of the ground, a large amount of an additive containing a cement-based curing agent is required, and there is a problem that costs increase. In addition, foundation piles made of soil cement have the problem of affecting the surrounding natural environment because the additive containing the cement hardener oozes into the surrounding ground.

In order to solve the above problems, the foundation pile of the present invention is
A support made of a ground improvement body solidified by injecting a binding substance into the ground;
And a ready-made pile body embedded in the ground with the tip side supported by the support body.

According to this structure, since the front end side of the pile body is supported by the support body, the features of the foundation pile made of a ready-made pile body and the foundation pile made of a ground improvement body are as follows. You can make use of each other's issues.
(A) Compared with the configuration in which the entire pile body is supported by the support, the size of the support can be reduced, so that the amount of materials used such as the binding substance can be reduced, and the construction cost Can be reduced.
(B) Since the pile diameter is increased by the support as compared with the foundation pile composed of the single pile body, the support force and horizontal force (inertial force during earthquake) can be improved.
(C) If it comprises so that the whole front-end | tip part of the said pile body may be covered with the said support body, compared with the foundation pile which consists of the said pile body single-piece | unit, it can improve the corrosion resistance of the front-end | tip part of this pile body. it can.

  Although it does not specifically limit as said support body, If it installs so that it may be supported by the support layer in the ground, since a support force can be improved, it is preferable.

Although it does not specifically limit as said ground improvement body, The following aspect is illustrated.
(1) The aspect which consists of a soil cement improved body solidified by inject | pouring the cement hardening agent as a binder into the ground. The improved soil cement is, for example, a deep-mixing method that injects a slurry cement hardening material into the ground, agitates and mixes with the ground, and chemically solidifies, and rotates ultra-high pressure chemicals with air into the ground. The method of forming an improved body by simultaneously spraying and cutting the ground, and the method of forming an improved body by rotating and spraying ultra-high pressure water with air into the ground to cut the ground and simultaneously filling with chemicals Or the like.
(2) The aspect which consists of a chemical | medical solution injection improved body solidified by inject | pouring the chemical | medical solution as a binder into the ground. The chemical solution injection improved body can be formed, for example, by a method in which an injection tube is installed in a hole excavated in the ground and the chemical solution is injected into the ground using the injection tube.

Although it does not specifically limit as a coupling | bonding aspect of the said pile and the said support body, The following aspect is illustrated.
(A) The said pile body is the aspect couple | bonded with this support body by the front end side being inserted in this support body before hardening of the said support body. Examples of this aspect include those described in [Best Mode for Carrying Out the Invention] to be described later.
(B) The said pile body is the aspect by which the front end side was couple | bonded substantially simultaneously with construction of the said support body. As this aspect, the pile body is made hollow, and the binding substance is injected into the ground through the pile body, so that the front end side of the pile body is joined substantially simultaneously with the construction of the support body. This is illustrated.
(C) A mode in which the pile body is inserted and joined in the support body after the support body is cured. As this aspect, a hole is made in the cured support body, or the support body is cured in a state where a hole is provided, and the support body is joined by inserting the front end side of the pile body into the hole. This is illustrated.

  An example in which a resin or an emulsion thereof is added to the ground improvement body is illustrated.

    Although it does not specifically limit as said resin, An epoxy resin, an acrylic resin, EVA (ethylene-vinyl acetate copolymer resin) etc. are illustrated.

  According to this structure, the intensity | strength of the said support body can be improved with resin or its emulsion. Moreover, the adhesive force with the said pile body can be improved, and the integrity of the said support body and the said pile body can be improved.

  An example in which short fibers are added to the ground improvement body is illustrated.

  Although it does not specifically limit as a material of the said short fiber, Vinylon, PP (polypropylene), PE (polyethylene), an acryl, steel etc. are illustrated. Moreover, it is although it does not specifically limit as a fiber length of the said short fiber, Setting to 5-60 mm is illustrated. The range is less than 5 mm because the effect of improving the strength of the support is small, and if it exceeds 60 mm, the workability deteriorates because it is too long (for example, it is difficult to pass through the piping for feeding into the ground). This makes it difficult to pump.

  According to this configuration, the strength of the support can be improved.

  The said pile body illustrates the aspect by which the surface of the front end side was formed in the rough surface.

  Although it does not specifically limit as a formation method of the said rough surface, The aspect formed by roughing the said surface, the aspect formed by adhere | attaching a granule on the said surface, etc. are illustrated.

  According to this structure, the adhesive force with the said support body can be improved, and the integrity of the said support body and the said pile body can be improved.

  An example in which an auxiliary support made of the ground improvement body having a lower strength than the support is formed on the upper side of the support is illustrated.

  The auxiliary support is not particularly limited, but is preferably formed integrally with the upper side of the support. Moreover, you may make it form the said auxiliary | assistant support body to the upper end side of the said pile body, or an upper side from an upper end. A specific aspect for reducing the strength of the ground improvement body is not particularly limited, but an aspect in which the amount of additive (the binding substance, resin or emulsion thereof, the short fiber, etc.) added to the ground improvement body is reduced or The mode which changed the kind of the said additive to a ground improvement body into the thing with a weak binding force is illustrated.

  When the support body and the pile body are embedded in the ground, the ground is mechanically excavated and stirred, so the strength of the ground around the pile body is weakened. Since the said auxiliary support body is formed in the ground around the said pile body, the adhesive force with respect to the ground of a foundation pile can be improved. Further, since the strength of the auxiliary support is reduced as compared with the support, the amount of the additive added to the ground improvement body is reduced compared to the support, or the additive is less expensive than the support. Can be employed and can be constructed at low cost.

  The auxiliary support is exemplified in such a manner that the lower end side is formed with substantially the same strength as the support and the strength is reduced toward the upper side.

  According to this configuration, since the strength of the auxiliary support is changed substantially continuously from the strength substantially equivalent to that of the support, the stress due to the strength discontinuity between the auxiliary support and the support. Concentration can be avoided.

The basic structure of the present invention is
Two or more foundation piles according to any one of the aspects;
A beam body spanned over the upper ends of the two or more foundation piles.

  According to this configuration, by connecting the upper ends of the foundation piles to each other, the area for supporting the foundation of the building is widened compared to the case of the foundation pile alone, and the foundation can be uniformly supported over a wide range. Can be supported. For this reason, generation | occurrence | production of the basic hair crack can be suppressed, for example.

  The said beam body illustrates the aspect by which the some carbon fiber extended in the length direction was arrange | positioned on the surface.

  The method for disposing the carbon fiber is not particularly limited, but a method for disposing the carbon fiber by bonding with an epoxy or acrylic adhesive is exemplified.

  According to this configuration, since the strength of the beam body can be improved, the effect of the foundation structure can be further improved.

  According to the foundation pile according to the present invention, by taking advantage of each feature of a foundation pile made of a ready-made pile body and a foundation pile made of a ground improvement body, it has an excellent effect of being able to complement each other's problems. Play.

  Moreover, according to the foundation structure of this invention, there exists the outstanding effect that the foundation of a building can be supported with a uniform supporting force over a wide range.

  1-7 has shown the foundation pile 1 and the foundation structure 2 of one Embodiment which actualized this invention. As shown in FIG. 1 and FIG. 2, the foundation pile 1 of the present invention includes a support 3 made of a soil cement improved body formed in the ground 11, and the ground 11 in a state where the tip side is supported by the support 3. It has a ready-made pile 4 embedded therein. Further, the foundation structure 2 of the present invention includes two or more (a pair in this example) foundation piles 1 and a beam body 5 spanned on the upper end portion of the foundation pile 1. A building foundation 6 is supported on the upper side of the beam body 5.

  The support 3 is made of an improved soil cement formed by injecting and mixing the ground 11 and an additive mainly composed of a cement hardening agent by a deep mixing method, and is formed in a substantially cylindrical shape extending vertically. Has been. For example, the height of the support 3 is set to be equal to or larger than the diameter of the support 3. The support 3 is installed so as to be supported by the support layer 12 in the ground 11, thereby improving the support force of the support 3. As an apparatus for forming the support 3, a known excavation stirring apparatus for a deep mixing treatment method can be appropriately employed. As an additive for the soil cement improved body, a resin or an emulsion thereof may be appropriately added to a cement-based curing agent, or short fibers may be added.

The support 3 can also be changed as follows.
(1) The support body 3 is formed by charging and mixing a mass 13 such as stone or crushed stone together with the additive of the soil cement improvement body into the ground 11. For example, as shown in FIG. 3, a screw 14 concentric with the shaft 21 is provided in the excavation stirring shaft 21, and a lump 13 such as stone or crushed stone is put in, so that the soil cement improved body is added. For example, when discharging the object, the screw 14 is rotated and the lump 13 is also charged.
(2) Forming an auxiliary support body 7 made of a soil cement improved body having a strength lower than that of the support body 3 on the upper side of the support body 3. As shown in FIG. 4, the auxiliary support 7 of this example is integrally formed with the support 3, and the lower end side is formed to have substantially the same strength as the support 3 (addition amount of the additive of the soil cement improved body) Is substantially the same as the support 3), and the strength is reduced toward the upper side (the additive amount of the soil cement improved body is reduced).

  The pile body 4 is a ready-made one made of metal, wood, concrete or the like. Although it does not specifically limit as a form of the metal pile bodies 4, A steel pipe, a cast iron pipe, steel materials (H shape steel, L shape steel, C shape steel etc.) etc. are illustrated. Although it does not specifically limit as a penetration method to the ground 11 of the pile body 4, The aspect driven into the ground 11, the aspect embedded in the ground 11, the aspect screwed into the ground 11, etc. are illustrated. In this example, a cast iron pipe is adopted as the pile body 4. The pile body 4 is provided with a spiral strip 4a protruding at the tip, and is screwed into the ground 11 to penetrate. Moreover, as shown in FIG. 5, the surface of the front end side of the pile body 4 is formed in a rough surface by adhering the sand 15 as a granule with an adhesive.

  As the beam body 5 of the foundation structure 2, a ready-made one made of metal, wood, concrete, or the like can be appropriately employed. Although it does not specifically limit as a form of metal beam bodies 5, Steel materials (H section steel, L section steel, C section steel, etc.) are illustrated. Further, as shown in FIG. 6, a plurality of carbon fibers 17 extending in the length direction may be disposed on the surface of the beam body 5. FIGS. 7A and 7B show an example of a mode in which carbon fibers 17 are arranged on a beam body 5 made of H-section steel and FIG. Although it does not specifically limit as this carbon fiber 17, PAN type fiber (carbon fiber made from polyacrylonitrile), pitch type fiber (carbon fiber made from coal), PBO (polyparaphenylene benzobisoxazole) fiber Is illustrated. All of the exemplified fibers have an elongation of 3% or less and a high tensile elastic modulus. Therefore, bonding the fiber extending in one direction to the surface of the beam body 5 using an adhesive can reduce the displacement of the beam body 5. It can suppress, ie, can reinforce beam body 5, and can reduce the number of foundation piles 1 by this.

  It is preferable that the joint between the beam body 5 and the foundation pile 1 be firmly connected. As a method for connecting the joints, a known method can be appropriately employed, and is not particularly limited. For example, the connection is firmly performed by bolting, welding, fitting, or a combination thereof.

Next, an example of the construction method of the foundation pile 1 and the foundation structure 2 of the present invention will be described.
(1) The ground 11 is excavated to the depth of the upper end of the support 3 (in this example, the depth of the upper surface of the support layer 12) using the excavation and stirring device 20 of the deep mixing treatment method (FIG. 7A )reference). And in the depth of the upper end of the support body 3, the additive of a soil cement improvement body is inject | poured into the ground 11 from the front-end | tip part 21a of the excavation stirring shaft 21 of the excavation stirring apparatus 20, and this additive and the ground 11 are mixed. Then, after mixing and stirring to the depth of the lower end of the support 3, the excavation stirring shaft is extracted from the ground 11. Then, the uncured support 3 is formed in the support layer 12 (see FIG. 7B).

(2) The pile body 4 is screwed into the ground 11 and penetrates (see FIG. 7C). And it screws in until the front end side of the pile body 4 penetrates into the unhardened support body 3 (refer FIG.7 (d)). Thereafter, when the support 3 is consolidated, the foundation pile 1 is completed. The above is repeated and another foundation pile 1 is constructed.

(3) When the beam body 5 is bridged between the upper ends of the pair of foundation piles 1 and the joint portion between the beam body 5 and the foundation pile 1 is connected, the foundation structure 2 is completed (see FIGS. 1 and 2).

According to the foundation pile 1 of this example comprised as mentioned above, since the pile body 4 is supported by the support body 3 at the front end side, the foundation pile which consists of a ready-made pile body, and ground improvement are as follows. Taking advantage of each feature of the foundation pile made of the body, each issue can be complemented.
(I) Compared with the configuration in which the entire pile body 4 is supported by the support body 3, the size of the support body 3 can be reduced, so that the amount of additive used for the ground 11 can be reduced and the construction cost can be reduced. Can be reduced.
(B) Since the pile diameter is increased by the support body 3 as compared with a foundation pile made of a single pile body 4, the support force and horizontal force (inertial force during earthquake) can be improved.
(C) Since the entire tip portion of the pile body 4 is covered with the support body 3, the anticorrosion property of the tip portion of the pile body 4 is improved as compared with a foundation pile made of the pile body 4 alone. be able to.

  Moreover, in this example, since the pile body 4 penetrates into the ground 11 excavated and stirred by the deep mixing processing method when the support body 3 is formed, the workability of the foundation pile 1 is good.

  In addition, according to the foundation structure 2 of the present invention, by connecting the upper ends of the foundation piles 1 to each other, the area for supporting the foundation 6 of the building is widened compared to the case of the foundation pile 1 alone, and the foundation 6 can be supported with a uniform supporting force over a wide range. For this reason, generation | occurrence | production of the hair crack of the foundation 6 can be suppressed, for example.

In addition, this invention is not limited to the said embodiment, For example, it can also be suitably changed and embodied as follows, for example in the range which does not deviate from the meaning of invention.
(1) The foundation 6 of the building is directly supported by the foundation pile 1 of the present invention without adopting the foundation structure 2 of the present invention.
(2) By forming the support 3 on the upper side of the support layer 12 of the ground 11, the support 3 is supported on the upper surface of the support layer 12.
(3) The support body 3 made of the soil cement improved body is formed by a construction method other than the deep layer processing method.
(4) The support 3 is made of a chemical solution injection improved body that is solidified by injecting a chemical solution as a binding substance into the ground.
(5) Adopt the following as an aspect of the connection between the pile body 4 and the support body 3.
(5-1) A mode in which the front end side of the pile body 4 is coupled substantially simultaneously with the construction of the support body 3.
(5-2) A mode in which the front end side of the pile body 4 is inserted and coupled into the support body 3 after the support body 3 is cured.

It is sectional drawing which shows the foundation pile and foundation structure which concern on one Embodiment which actualized this invention. It is II arrow directional view of FIG. It is sectional drawing which shows the excavation axis | shaft for forming the support body of the foundation pile. It is a figure which shows the example of a change of the support body of the foundation pile. It is a side view which shows the lower end side of the foundation pile. It is a figure which shows the beam body of the same foundation structure. It is a figure which shows the construction method of the foundation pile and the foundation structure. It is sectional drawing which shows the foundation pile of a prior art example. It is sectional drawing which shows another conventional foundation pile.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foundation pile 2 Foundation structure 3 Support body 4 Pile body 5 Beam body 6 Foundation 7 Auxiliary support body 11 Ground 12 Support layer 15 Sand 17 Carbon fiber 20 Drilling stirring apparatus 21 Drilling stirring shaft

Claims (11)

A support made of a ground improvement body solidified by injecting a binding substance into the ground;
A foundation pile provided with a pre-made pile body embedded in the ground with the tip side supported by the support body.   The foundation pile according to claim 1, wherein the pile body is coupled to the support body by inserting a tip side of the pile body into the support body before the support body is cured.   The foundation pile according to claim 1, wherein the pile body is coupled at the tip side thereof substantially simultaneously with the construction of the support body.   The foundation pile according to claim 1, wherein a tip side of the pile body is inserted into and bonded to the support body after the support body is cured.   The foundation pile according to any one of claims 1 to 4, wherein a resin or an emulsion thereof is added to the ground improvement body.   The foundation pile according to any one of claims 1 to 5, wherein a short fiber is added to the ground improvement body.   The said pile body is a foundation pile as described in any one of Claims 1-6 in which the surface of the front end side was formed in the rough surface.   The foundation pile according to any one of claims 1 to 7, wherein an auxiliary support body is formed on the upper side of the support body. The auxiliary support body is formed of the ground improvement body having a strength reduced from that of the support body.   The foundation pile according to claim 8, wherein the auxiliary support body is formed such that the lower end side has substantially the same strength as the support body, and the strength is reduced toward the upper side. Two or more foundation piles according to any one of claims 1 to 9,
A foundation structure including a beam extending over the upper ends of the two or more foundation piles.   The foundation structure according to claim 10, wherein a plurality of carbon fibers extending in a length direction of the beam body are arranged on the surface.

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