JP3485809B2 - Connection structure of cast-in-place pile and foundation - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to seismic reinforcement (including liquefaction countermeasures), or in the existing foundation due to an increase in the load of the upper structure, the bearing capacity, the bearing capacity of the foundation itself (vertical and horizontal) and the time of earthquake. When the deformation performance is insufficient, it is covered with a cast-in-place pile that is constructed for the purpose of improving the proof strength and deformation performance of the foundation, or a bag that is created by inflating the bag with a filler and inserting it into the cutting hole even for a new foundation. The present invention relates to a connection structure between a columnar cast-in-place pile and a foundation.

[0002]

2. Description of the Related Art For example, as a reinforcement of an existing foundation,
20, existing footing 21 and existing piles as shown in Figure 21
There is a method in which piles 23 are added to the outside of 22 and footing 21 is also added to improve the bearing capacity, proof stress and deformation performance of the foundation during an earthquake.

However, this method of increasing piles and the like is insufficient in area only within the plane of the existing foundation, and cannot be used in a place where there is a site restriction or an empty head restriction directly below the existing structure.

In both cases of the pile foundation and the direct foundation, the ground beneath and around the entire ground is improved to directly under the foundation.
There are also methods such as increasing the ground strength directly under the existing piles, but with reinforcement by such a ground improvement method, the specified performance cannot be satisfied unless the entire area directly below the foundation or a wide area outside it is improved Since many of the above do not consider the existing piles, the cost is high as a result.

Therefore, without increasing the area and without removing the existing foundation, it is possible to easily and surely improve the bearing capacity, proof stress, and horizontal deformation performance of the foundation, and the existing pile is effective. It is proposed in Japanese Patent Application No. 8-285200 as a construction method for cast-in-place piles directly under the existing foundation that can be used.

As shown in FIGS. 13, 14 and 15 to 19, a vertical through hole 4 is formed in an existing foundation 1 having an existing pile 2 and the rod is formed by using the through hole 4. The ground is cut from 5 by a high-pressure injection replacement method or the like to form the holes 3 filled with muddy water. In that case, mud water such as bentonite may be replaced. The cut earth and sand is discharged upward from the gap of the double pipe or the triple pipe inserted in the through hole 4.

The bag 6 is inserted together with the rod 7, and the bag 6 is filled with a filling material 8 such as cement milk, mortar or concrete and spread out, and the columnar ground improvement body covered with the bag 6 is piled up in the pile body 9. Build as. In the figure, 10 indicates a support layer.

[0008]

[Problems to be Solved by the Invention] Japanese Patent Application No. 8-285200
Of course, when a columnar pile body covered with a bag, which is a cast-in-place pile constructed by the construction method shown in No. 6, is constructed below the existing foundation such as footings, foundation beams and foundation slabs as described above. Even when the cast-in-place pile and the foundation are newly installed, the connection between the pile and the foundation is mainly due to the frictional resistance between the filling material filled in the bag and the lower portion of the foundation.

Therefore, the load cannot be sufficiently transmitted from the foundation to the pile, and the horizontal proof strength, the vertical pull-out proof strength, and the vertical pushing proof strength cannot be obtained sufficiently, and the proof strength and the deformation performance of the foundation are not sufficient.

The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional example, and when forming a bag pile for filling the inside with a filling material as a cast-in-place pile, surely fix the pile to the foundation so that the pile is removed from the foundation. The purpose of the present invention is to provide a connection structure between a cast-in-place pile and a foundation that ensures the transmission of horizontal force, vertical pulling force, vertical pushing force, and moment to the foundation, and improves the proof strength and deformation performance of the foundation.

[0011]

In order to achieve the above object, the present invention firstly cuts the ground and inserts a bag into the cutting hole.
Put the cement milk and mortar in the bag with a rod.
It is made by filling it with a filling material such as concrete or inflating it.
Connection between the column-shaped cast-in-place pile covered with a bag and the foundation
In the composite structure, the pile head was expanded to create multiple steel
The lower part of the bar-shaped steel material such as a rod is placed in the pile head of the expanded pile.
Insert the top of the bar-shaped steel into the foundation above the pile.
And connecting the pile and foundation with the bar-shaped steel,
2, cut the ground, insert a bag into the cutting hole,
With rod in cement milk, mortar or concrete
In a bag, filled with filling material such as REIT and inflated to create
The odor of the joint structure of the covered columnar cast-in-place pile and the foundation
The lower part of the bar-shaped steel material such as a steel rod into the pile head of the pile.
And insert the top of the bar steel into the foundation above the pile.
However, the bar-shaped steel material is anchored to the foundation with an anchor through the plate body.
And connecting the pile and the foundation with the bar-shaped steel material.
, Cut the ground, insert the bag into the cutting hole,
With a rod of cement milk, mortar or concrete
Cover with a bag, which is created by filling and inflating a filling material such as a sheet.
Odor of the joint structure between a broken column cast-in-place pile and a foundation
Of the bar-shaped steel that is the rod that fills the bag with the filler.
Insert the lower part into the pile head of the pile and place the upper part of the bar-shaped steel
Insert into the foundation above the pile, and use the bar-shaped steel material to
The idea is to combine the foundations .

Fourth, the foundation is an existing foundation, and the bar-shaped steel material is inserted into the pile head through a through hole formed in the existing foundation. Fifth, the inserted bar-shaped steel material and the through hole. The gist of the present invention is to fill the gaps between the base and the pile head with the existing foundation with a filler such as mortar.

According to the first aspect of the present invention, the steel rod is inserted so as to extend over both the pile head of the cylindrical cast-in-place pile covered with the bag and the foundation above it. Since it is connected with a bar-shaped steel material such as, the connection is reliable, horizontal force can be reliably transmitted from the foundation to the pile side, and horizontal proof strength is improved.

In addition to the above-mentioned action, by fixing with a plurality of bar-shaped steel materials, the degree of fixing of the pile head is increased,
Not only the horizontal force but also the moment can be transmitted, and the proof strength of the foundation is further improved.

According to the second aspect of the present invention, in addition to the above action, the bar-shaped steel material is anchored to the foundation by the anchor, so that the pull-out resistance of the pile is improved.

According to the present invention as set forth in claim 3, in addition to the above-mentioned function, the rod for filling the filling material in the bag can be left as it is in the bag and used as a bar-shaped steel material. In such a case, it is possible to reduce the members and the construction process.

According to the present invention of claim 4, in addition to the above-mentioned action, when the foundation is an existing one, a through hole is bored in the existing foundation so that the existing foundation can be inserted through the through hole. The bar-shaped steel material can be easily inserted from above to the pile head below.

According to the fifth aspect of the present invention, in addition to the above action, the filling of the filler increases the adhesion between the foundation and the pile, and the vertical force, horizontal force, etc. can be transmitted from the foundation to the pile. It will be more reliable and the vertical pushing resistance will be improved.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a vertical sectional front view for explaining the concept of the connection structure between a cast-in-place pile and a foundation of the present invention, and FIG. 2 is a plan view of the same as above. In the present invention, it is constructed by the construction method shown in Japanese Patent Application No. 8-285200. As with the cast-in-place
As shown in FIGS. 13 to 19, for example, a vertical through hole 4 having a diameter of about 200 mm is bored in an existing foundation (footing) 1 having an existing pile 2 and the through hole 4 is used to replace the rod 5 with high pressure injection. The ground is cut by the construction method and made into muddy water. In that case, mud water such as bentonite may be replaced.

In the case of the high-pressure injection replacement method, the cut earth and sand is discharged upward from the void of the double pipe or triple pipe inserted in the through hole 4. The bag 6 is inserted together with the rod 7 in the closed state through the through hole 4, the filler 8 such as mortar is filled and spread in the bag 6, and the cylindrical ground improvement body covered with the bag 6 is piled. Build as body 9.

FIG. 3 shows the pile body 9 constructed as described above. The bag 6 has a cylindrical shape, and the material of the bag 6 is polyvinyl alcohol fiber, polyester fiber, polyamide fiber, polyethylene fiber. , Aramid fiber,
PBO (polyparaphenylene benzobisoxazole)
High-strength fibers such as fibers, glass fibers, carbon fibers, and metal fibers were used as warp and weft to form a bag-like woven fabric.

The bag 6 has a different bag diameter between the main body of the pile body 9 and the footing penetration portion, and the bag of the footing penetration portion is φ150 mm.
It is composed of a woven fabric with a small diameter of about φ200 mm.

Since the bag 6 is made of high-strength fiber as described above, the bag 6 can be provided with the same function as the reinforcing bars in the vertical direction and the circumferential direction, and the bag 6 is used as a mold. In this case, since the filling material 8 such as cement milk or mortar filled is replaced with muddy water, qu = 300 kgf
High reinforcement of / cm ^{2 to} 500 kgf / cm ² is possible.

With respect to the pile body 9 thus constructed,
In the present invention, as shown in FIGS. 1 and 2, a steel rod 11 is inserted as a bar-shaped steel material from the through hole 4 provided in the existing foundation 1 to the pile head 9a of the pile body 9, and the existing foundation is formed by the steel rod 11. 1 and the pile body 9 were connected, and further, the gap between the steel rod 11 and the existing foundation 1 and the gap between the existing foundation 1 and the pile body 9 were filled with a high-strength filler 12 such as mortar.

Next, a method of fixing the pile body 9 to the existing foundation 1 in this way will be described. As shown in FIG. 3, the upper portion of the through-hole 4 provided in the existing foundation 1 is expanded to form the expanded-diameter portion 4a, and as shown in FIG. Insert into the pile head 9a of the body 6. In the figure, 11a is a steel rod
11 shows a nut provided on the head of 11 as a locking member for the expanded diameter portion 4a.

Next, as shown in FIG. 5, the steel rod 11 and the existing foundation 1
The filling material 12 such as high-strength mortar is filled in the gap in the through hole 4 portion between the and the existing foundation 1 and the pile head 9a, and finally formed on the upper portion of the existing foundation 1 as shown in FIG. The concave portion formed by the expanded diameter portion 4a is filled with a filling material 12 such as mortar to make the upper surface of the existing foundation 1 smooth.

By connecting the existing foundation 1 and the pile body 9 with the steel rod 11 in this way, horizontal force is surely transmitted from the existing foundation 1 to the pile body 9 and the horizontal proof strength is improved. In addition, steel rod 11 and existing foundation 1, and existing foundation 1 and pile head 9
By injecting the filler 12 into the gap with a, the adhesion between the existing foundation 1 and the pile body 9 is enhanced, and the vertical force can be transmitted from the existing foundation 1 to the pile body 9 to improve the vertical pushing resistance. To do.

As shown in FIGS. 7 and 8, the existing foundation 1
A plurality of through-holes 4 are bored into the pile body 9 and a plurality of bar-shaped steel materials are inserted into the pile body 9. In the illustrated example, one steel rod 11 is inserted in the center in the radial direction from the existing foundation 1 to the pile head 9a through the through hole 4 so as to surround the periphery in a circular shape. did. In this case, even if a plurality of reinforcing bars or steel bars 13 are arranged around the steel bar 11 as a center, the diameter of the reinforcing bar or steel bar 13 is smaller than that of the steel bar 11, so the diameter is limited. It can also be arranged on the pile head 9a.

As a result, the degree of fixation of the pile head 9a to the existing foundation 1 is enhanced, and not only the horizontal proof strength and the vertical pull-out proof strength are improved, but also the moment can be transmitted and the pile body 9 is sufficiently reinforced.

The first embodiment of the present invention is as shown in FIG.
To, and Construction and enlarged the pile head 9a of Kuitai 9, inserting a plurality of bar-shaped steel material to pile head 9a, which is increased in diameter. In this case, since the pile head 9a is expanded in diameter and the portion into which the bar-shaped steel material can be inserted is increased, the bar-shaped steel material to be used is all steel bars 11, and the steel bar 11 having a large length is arranged in the center. Then, a plurality of, for example, six short steel rods 11 having a length are arranged so as to surround the circumference in a circle.

As a result, not only the horizontal proof strength and the vertical pull-out proof strength are improved, but the contact area between the pile head 9a and the existing foundation 1 is expanded, so that the proof strength against the vertical pushing force is also improved.

FIG. 10 shows a second embodiment of the present invention, in which a plate body 14 is attached to the head of a steel rod 11 which is a bar-shaped steel material.
14 was fixed to the upper surface of the existing foundation 1 with an anchor 15. As a result, the steel rod 11 is anchored to the existing foundation 1 via the plate body 14.
Since it is fixed on the sheet, the pulling resistance is further improved.

Also, a nut 11b is provided on the side of the lower portion of the steel rod 11.
If attached, the pull-out resistance will be further improved.

FIG. 11 shows a third embodiment of the present invention, which is a bag 6
The rod 7 used to inject the filling material 8 into the inside of the can be replaced with the steel rod 11 and used as it is as a bar-shaped steel material. In this case, all or part of the rod 7 is buried in the bag 6 or the existing foundation 1, and the rod 7 is filled with a filler 16 made of high-strength mortar or the like to form a bar-shaped steel material. .

FIG. 12 shows the fourth embodiment and the third embodiment.
When the rod 7 is used as a bar-shaped steel material in the same manner as described above, a screw is formed inside the upper portion of the rod 7 to form the threaded portion 7a, while the steel rod is also threaded on the circumferential surface to form the threaded portion 11d. A steel rod 11c with a screw is provided, the rod 7 is buried in the bag 6 and the existing foundation 1, and the lower portion of the rod 7 other than the screw portion 7a is filled with a filler 16 such as high-strength mortar. The steel rod 11c with a screw is inserted into the screw portion 7a at the upper portion thereof, and the screw portion 11d is screwed into the screw portion 7a to fix the steel rod 11c to the rod 7. Thus, the rod 7 and the steel rod 11c with a screw form a bar-shaped steel material.

Although not shown, a steel rod with a screw
The length of the rod 7 with which the 11c is screwed should be as short as the length of the steel rod 11c with a screw, the filling material 16 is not filled, and only the combination of the steel rod 11c with a screw and the rod 7 is used. It is also possible to form a steel strip.

The implementation mode described above, it is possible to assume the form of a combination, respectively. Further, as the bar-shaped steel material, the steel rod 11, the reinforcing bar or the steel rod 1 as described above is used.
3, the present invention is not limited to the rod 7, and if the existing foundation 1 and the pile head 9a are vertically connected to each other so that the force can be reliably transmitted from the existing foundation 1 to the pile body 9, for example, ,
H-section steel, I-section steel and the like can also be used.

Further, before you facilities embodiment, opening a bag 6 forming a Kuitai 9 it is assumed that provided only on the rod 7 is inserted, it is not limited thereto as the structure of the bag 6 As shown in FIG. 22, the bag 6 is provided with a predetermined opening 17 through which the filler 8 can flow out, and the filler 8 is passed through the opening 17 to form a gap between the bag 6 and the hole 3. The present invention can also be applied to the pile body 9 that has flowed out to the end and is filled with the filling material 8.

In this case, since the bag 6 is sandwiched between the filling materials 8, the integrity of the bag 6 and the filling material 8 is improved, and the predetermined horizontal proof strength and deformation performance can be reliably exhibited. The shape of the holes provided in the bag 6 is not limited to the rectangular opening as shown in FIG. 22, but the bag 6 may be provided with polyvinyl alcohol fibers, polyester fibers, polyamide fibers, polyethylene fibers as shown in FIG. Aramid fiber, P
Consists of a lateral belt 18a and a longitudinal belt 18b made of high-strength fibers such as BO (polyparaphenylene benzobisoxazole) fiber, glass fiber, carbon fiber, and metal fiber, which are woven into a bag shape in a lattice pattern. The opening 17 may be secured by opening the stitches of the lateral belt 18a and the longitudinal belt 18b.

[0040] Furthermore, before you facilities embodiment, foundation Kuitai 9 is coupled has been the existing foundation 1, but the invention is not limited to this, although not shown, Ya pile body 9 of the new It can also be applied to the construction of the foundation. In this case, after the bag-shaped pile body 9 is constructed as described above, the lower part of the bar-shaped steel material is placed inside the pile body 9 so that the upper part projects upward. Then, by placing a form on the pile body 9 in this state and placing concrete in the form, a foundation having a bar-shaped steel material inside can be formed. Then, in this state, the pile body 9 is joined to the new foundation through the bar-shaped steel material.

In the case of a new installation, except for the above, FIGS.
Also, the structure shown in FIGS. 26 to 28 can be adopted.

In FIGS. 23 to 25, a reinforcing bar 24 having a cage-like reinforcing bar shape in which a reinforcing bar 24a is wound around the head of the bag 6 filled with the filling material 8 is embedded so that its upper half portion projects. , Footing, slab, etc. 25 are installed so that the upper half part is embedded.

26 to 28, the bag 6 filled with the filling material 8 is formed so that the head itself protrudes above the ground, and the foot of the protruding bag 6 is fitted into the footing, slab or the like 25. Is to be constructed by embedding the upper half part.

[0044]

As described above, the connection structure of the cast-in-place pile and the foundation of the present invention is based on the pile head of the pile when the bag pile filled with the filling material is formed as the cast-in-place pile. It can be securely fixed to the pile to ensure the transmission of horizontal force, vertical pulling force, vertical pushing force and moment from the foundation to the pile, and improve the proof strength and deformation performance of the foundation.

[Brief description of drawings]

FIG. 1 shows the concept of the connection structure of cast-in-place pile and foundation of the present invention.
It is a vertical front view explaining .

FIG. 2 shows the concept of the connection structure of cast-in-place pile and foundation of the present invention.
It is a transverse plan view explaining .

FIG. 3 is a vertical sectional front view showing a first step of construction of a cast-in-place pile in which the present invention is carried out.

FIG. 4 is a vertical sectional front view showing a second step of construction of a cast-in-place pile in which the present invention is carried out.

FIG. 5 is a vertical sectional front view showing a third step of construction of a cast-in-place pile in which the present invention is carried out.

FIG. 6 is a vertical sectional front view showing a fourth step of construction of a cast-in-place pile in which the present invention is carried out.

FIG. 7 is a vertical cross-sectional front view showing an applied embodiment of the joint structure of the cast-in-place pile and the foundation of the present invention.

FIG. 8 is a cross-sectional plan view showing an applied embodiment of the joint structure of the cast-in-place pile and the foundation of the present invention.

FIG. 9 is a vertical cross-sectional front view showing the first embodiment of the connection structure between the cast-in-place pile and the foundation of the present invention.

FIG. 10 is a second connecting structure of cast-in-place pile and foundation of the present invention.
It is a vertical section front view showing an embodiment.

FIG. 11 is a third view showing the connection structure of the cast-in-place pile and the foundation of the present invention.
It is a vertical section front view showing an embodiment.

FIG. 12 is a fourth view showing the connection structure of the cast-in-place pile and the foundation of the present invention.
It is a vertical section front view showing an embodiment.

FIG. 13 is a vertical sectional front view showing an example of a conventional connection structure between a cast-in-place pile and a foundation.

FIG. 14 is a plan view showing an example of a conventional connection structure between a cast-in-place pile and a foundation.

[Fig. 15] First construction of cast-in-place pile below existing foundation
It is a front view which shows a process.

[Fig. 16] Second construction of cast-in-place pile below existing foundation
It is a front view which notched a part which shows a process.

[Fig. 17] Third construction of cast-in-place pile below the existing foundation
It is a front view which notched a part which shows a process.

FIG. 18: Third construction of cast-in-place pile below existing base 4
It is a front view which notched a part which shows a process.

[Fig. 19] Fifth construction of cast-in-place pile below existing foundation
It is a front view which notched a part which shows a process.

FIG. 20 is a vertical sectional front view showing another example of the conventional connection structure between a cast-in-place pile and a foundation.

FIG. 21 is a plan view showing another example of a conventional connection structure between a cast-in-place pile and a foundation.

FIG. 22 is a partially cutaway front view showing another example of the pile body to which the present invention is applied.

FIG. 23 is a partially cutaway front view showing still another example of the pile body according to the present invention.

FIG. 24 is a vertical sectional front view showing the construction example of the new foundation during construction.

25 is a cross-sectional view taken along the line AA of FIG.

FIG. 26 is a vertical cross-sectional view after completion of construction showing an example of construction in the case of a new foundation.

FIG. 27 is a vertical sectional front view showing the other example of the construction of a new foundation during construction.

28 is a cross-sectional view taken along the line BB of FIG. 27.

FIG. 29 is a vertical cross-sectional view after completion of construction showing another example of construction in the case of a new foundation.

[Explanation of symbols]

1 ... Existing foundation 2 ... Existing pile 3 ... Hole 4 ... Through hole 4a ... Expanded part 5 ... Rod 6 ... Bag 7 ... Rod 8 ... Filler 7a ... Screw part 9 ... Piles 9a ... Pile head 10 ... Support layer 11 ... Steel rod 11a ... Nut 11b ... Nut 11c ... Steel rod with screw 11d ... Screw part 12 ... Filling material 13 ... Rebar or steel rod 14 ... Plate 15 ... Anchor 16 ... Filling material 17 ... Opening 18a ... Lateral belt 18b ... longitudinal belt 21 ... existing footing 22 ... existing pile 23 ... extended pile 24 ... reinforcing rebar 24a ... belt rebar 25 ... footing, slab, etc.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Hira 2-19-1, Tobita, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (56) Reference JP-A-10-25737 (JP, A) ( 58) Fields surveyed (Int.Cl. ⁷ , DB name) E02D 27/12

Claims (5)

(57) [Claims] 1. The ground is cut, a bag is inserted into the cutting hole, and a filling material such as cement milk, mortar, or concrete is filled with a rod into the bag, and the bag is inflated. and at the junction structure between the columnar place pile and foundation, and enlarged the pile head and reclamation, the lower portion of the bar-like steel material of the steel rod or the like of the plurality of in pile head of pile said upset A cast-in-place pile-foundation coupling structure, characterized in that the pile-shaped steel material is inserted and the upper part of the bar-shaped steel material is inserted into the foundation above the pile to connect the pile and the foundation with the bar-shaped steel material. 2. The ground is cut, a bag is inserted into the cutting hole, and a filling material such as cement milk, mortar or concrete is filled with a rod into the bag to inflate the bag, and the bag is covered with the bag. In the joint structure of a columnar cast-in-place pile and a foundation, the lower part of the bar-shaped steel material such as a steel rod is inserted into the pile head of the pile, and the upper part of the bar-shaped steel material is placed in the foundation above the pile. Insert the bar-shaped steel through the plate and anchor it
A connection structure for a cast-in-place pile and a foundation, characterized in that the pile and the foundation are fixed to each other by the bar-shaped steel material. 3. The ground is cut, a bag is inserted into the cutting hole, and a filling material such as cement milk, mortar or concrete is filled with a rod into the bag, and the bag is inflated. In a joint structure of a columnar cast-in-place pile and a foundation, the lower part of the bar-shaped steel material, which is a rod for filling the filling material in the bag, is inserted into the pile head of the pile to form a bar shape. A connection structure of a cast-in-place pile and a foundation, wherein an upper part of the steel material is inserted into a foundation above the pile, and the pile and the foundation are connected by the bar-shaped steel material. 4. The cast-in-place pile according to any one of claims 1 to 3, wherein the foundation is an existing foundation, and the bar-shaped steel material is inserted into the pile head through a through hole formed in the existing foundation. And the underlying bond structure. 5. The cast-in-place according to claim 1, wherein a filler such as mortar is filled in a gap between the inserted bar-shaped steel material and the through hole and a gap between the existing foundation and the pile head. Combined structure of pile and foundation.