JP2000291371A - Perforated wall construction method for deep foundation piles - Google Patents

Abstract

(57) [Problem] To provide a method for constructing a hole wall for a deep foundation pile, which can avoid the risk of dropping a heavy first hole wall when excavating a second downhole. SOLUTION: A form 9 having a predetermined height is used, and every time a hole having a predetermined depth is excavated, concrete C is poured and filled between the form 9 and the ground 10, and after the concrete is solidified, the form is filled. Frame 9
In the hole wall construction method in which concrete is poured while sequentially excavating and excavating, a first drilling hole H1 of a predetermined depth excavated first from the ground surface is a straight hole having a predetermined diameter. 1 and an enlarged countersink hole 2 surrounded by the open end of the straight hole
And forming a hole flange F integral with the first hole wall G1 by casting and filling concrete into the countersink hole 2 at the time of constructing the first hole wall G1. I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a hole wall for a deep foundation pile mainly constructed on soft ground.

[0002]

2. Description of the Related Art Conventionally, a form having a predetermined height is used, and concrete is poured between a form and a ground every time a hole having a predetermined depth is excavated. There is known a method of constructing a hole wall for a deep foundation pile, in which concrete is cast while being excavated, lowered and excavated one after another.

[0003]

In the above-mentioned conventional hole wall construction method, the first drilling hole to be firstly excavated from the ground surface is formed as a straight hole having an inner diameter matching the outer diameter of the wall. ,
The hole diameter is set to a large diameter such that the pile diameter is 10 m or more, for example.
When the concrete pitch is increased to, for example, about 1.5 m to 2 m, the joint between the hole wall and the ground cannot withstand a heavy hole wall load, and the heavy hole wall is excavated at the time of excavation of the second downhole. There was a risk that the first hole wall would fall.

[0004] Further, the conventional hole wall construction method uses a tubular form having an outwardly projecting flange for storing concrete at the lower end, so that the concrete pouring portion (between the form and the ground) is used. It is difficult to assemble the reinforcing bars in a cage shape.In order to insert a vertical reinforcing rod that straddles each concrete casting boundary into the hole wall itself, a reinforcing bar insertion hole is formed in the outwardly projecting flange at the lower end of the formwork. It is necessary to temporarily fix the reinforcing rod inserted in the hole so that it does not fall off by concrete casting, the work is difficult, and a gap is formed at the joint between the form flange and the ground. There is a possibility that the cast concrete may flow downward from there, and there is a problem that it is difficult to take countermeasures.

A first object of the present invention is to provide a method of constructing a hole wall for a deep foundation pile which can avoid the risk of the heavy first hole wall falling when excavating the second downhole. .

A second object of the present invention is to make it possible to easily assemble a reinforcing bar for reinforcing a wall into a concrete-casting portion in a cage shape, and to easily incorporate a vertical bar for integrating the holes between the holes. Another object of the present invention is to provide a method of constructing a hole wall for a deep foundation pile, which can prevent the concrete from flowing out.

[0007]

In order to achieve the first object, the present invention provides a method for constructing a well-known hole wall as described above, wherein a first downhole having a predetermined depth to be firstly excavated from the ground surface is formed. It is formed by a concentric continuous hole of a straight hole having a predetermined diameter and an enlarged countersunk hole surrounded by the opening end of the straight hole, and concrete is also poured into the countersunk hole when the first hole wall is constructed. The filling is performed to form a hole wall flange integral with the first hole wall.

The hole wall flange has a function of supporting the load of the heavy first hole wall in synergy with the bonding force between the hole wall and the ground, so that the hole diameter becomes, for example, a pile diameter of 10 m or more. Even if the diameter is large and the concrete pitch is larger than the conventional one (for example, about 1.5 m to 2 m), the problem that the heavy first hole wall falls during the excavation of the second downhole. Does not happen.

In order to achieve the second object, the present invention relates to the above-described conventionally known method for constructing a hole wall, wherein the vertical form is assembled by sequentially connecting the formwork to the separated position along the inner periphery of the hole. It is composed of the required number of segment template plates long, and every time a hole of a predetermined depth is excavated, hard elastic bodies of a predetermined thickness are arranged in a ring on the outer peripheral portion of the hole bottom plate and sequentially laid and fixed,
A vertical reinforcing bar is pierced into the hard elastic body to assemble the reinforcing bar for the wall, and after assembling the reinforcing bar, the formwork is assembled so as to house the reinforcing bar for the wall on the elastic body. It is characterized in that concrete is poured and filled to embed the reinforcing steel for wall reinforcement.

According to this method, the work of assembling the reinforcing bar for the wall into the concrete placing portion in a basket-like manner can be easily performed, and the vertical reinforcing bar for integrating the holes between the holes can be pierced into the hard elastic body. In addition to this, it is possible to easily prevent the cast concrete from flowing out and to reliably prevent the concrete from flowing out by the contact of the mold with the hard elastic body.

Each time a hole of a predetermined depth is excavated, the inner peripheral surface of the hole is shaped by shaping the inner peripheral surface of the hole, setting the reinforcing steel sideways and spraying concrete to a thickness of several tens of millimeters, thereby forming a ground on the inner peripheral surface of the hole. By forming a coating layer that protects the mountain and prevents its collapse, it is possible to prevent the collapse of the ground between excavating the hole and assembling the reinforcing steel bar and the formwork.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for constructing a hole wall for a deep foundation pile according to this embodiment will be described below in the order of working steps.

(1) Excavation work of the first drilling hole A predetermined depth L1 (for example, 2 m depth) from the ground surface W of the soft ground
1 is excavated as shown in FIG. 1 using a caterpillar traveling type excavator U as shown in FIG. The first drill hole H1 is formed by a concentric continuous hole of a straight hole 1 having a predetermined diameter D (for example, a diameter of 13.5 m) and a large-diameter countersunk hole 2 surrounded by an opening end of the straight hole. In this embodiment, the diameter E of the countersink hole 2 is 15 m, the countersunk hole width d is 75 cm, and the depth a is 50.
cm.

(2) Shaping and Leveling of the First Drilling Hole After excavation of the first drilling hole H1, the inner peripheral surface of the hole is neatly shaped using a shaping jig and the bottom portion is flattened. Level the ground.

(3) Set-up reinforcing bar driving work The set-up reinforcing bars 3 and 4 are driven into the inner peripheral surface portion of the straight hole 1 and the flat step surface portion of the countersunk hole 2 at appropriate intervals in the circumferential direction as shown in FIG. Fix it.

(4) Concrete spraying operation After the set-up reinforcing bars 3 and 4 are driven, concrete is sprayed on the inner peripheral surface of the hole H1 to a thickness of several tens of millimeters, for example, 20 to 30 mm. Next, coating layers 1a and 2a for protecting the ground 10 and preventing its collapse are formed as shown in FIG.

(5) Laying and Fixing the Hard Elastic Body After forming the coating layers 1a and 2a, the hard elastic body 5 made of a hard styrene foam plate having a predetermined thickness (for example, a thickness of 50 cm) is formed on the outer periphery of the hole bottom plate h. 12 are laid one after another in an annular manner as shown in FIG.
As shown in FIG. 2, each of the elastic members 5 is fixed on the hole bottom plate h by vertically driving, and the gap 5a between the plates of the hard elastic member 5 shown in FIG. Further, a flange outer mold 7 formed of plywood is provided at a position along the inner periphery of the countersink hole 2 with a support rod 7.
a is interposed and fixed as shown in FIG.

(6) Marking work of reinforcing bars and formwork Marks indicating the assembling position of the reinforcing bar and the formwork are formed on the upper surface of the elastic body 5 and displayed.

(7) Work for assembling the reinforcing bar for wall reinforcement Along the inner periphery of the hole H1, a vertical bar 8a, a horizontal bar 8b and a hoop bar 8 are provided.
The wall reinforcing reinforcing bar 8 composed of c is assembled in a basket shape as shown in FIG. At the time of assembling the reinforcing bar, the vertical bar 8a is pierced into a hard elastic body (styrene foam plate) 5 as shown in FIG. 5 so as to protrude into the bottom of the hole, and the vertical bar 8a and the horizontal bar 8b are set up as described above. , 4 by welding.

(8) Assembling work of the inner formwork After the assembling of the reinforcing bar 8, the inner formwork 9 is assembled as shown in FIG. 11, the formwork anti-shake member 12 and the pipe support 13 are used for fixing. The pipe support 13 is of a turnbuckle extendable type, and is stretched and attached between the formwork 9 and a digging machine U stopped at the center position of the hole bottom plate as shown in FIG.

The formwork 9 is sequentially laterally connected to the separated position along the inner periphery of the hole (connected using a connecting tool such as a bolt and a nut).
.., 9n (shown in FIG. 13). Every other segment template 9a of this form 9
9c are provided with a concrete pouring port 19a at the upper end and a window frame 19b for forming the next pouring port at the lower end as shown in FIGS.

(9) Concrete Casting Work After assembling and fixing the form 9, a reinforcing bar 8 for reinforcing the wall 8 is provided between the form 9 and the ground 10 and between the outer form 7 and the inner form 9.
Cast concrete C as shown in FIG.
By the solidification of the concrete, a first hole wall G1 having a wall thickness of about 50 cm is constructed. At the time of constructing the first hole wall G1, concrete C is poured into the countersink hole 2 (between the outer formwork 7 and the inner formwork 9) as shown in FIG. Is formed.

(10) Demolding operation of the mold After the concrete C is solidified, the mold 7.9 is demolded. After removing the outer form 7, the remaining space 2 of the countersink hole 2 is removed.
a is filled with concrete C, and a flange extension f integrated with the hole wall flange F is added.

(11) Excavation work of the second drill hole After the construction of the first hole wall G1, a predetermined depth L2 (for example, 1.5 m)
A second digging hole H2 (depth) is excavated using a digging machine U as shown in FIG. During the excavation of the second drill hole H2 or at the end of the excavation, the Styrofoam plate 5 is pulled downward as shown in FIG. Due to the removal of the Styrofoam plate 5, the lower portion of the vertical reinforcing bar 8a of the reinforcing bar 8 protrudes from the lower end surface of the first hole wall G1 as shown in FIG.
1, a connecting member for integrating G2 (shown in FIG. 14).

(12) Shaping and Leveling of Second Drilling Hole After excavation of the second drilling hole H2, the inner peripheral surface of this hole is shaped in the same manner as in (2) and the bottom part is leveled. I do.

(13) Set-up reinforcing bar driving work A second set-up reinforcing bar 3a is laterally driven into the inner peripheral surface of the second drilling hole H2 in the same manner as in the above (3) and is driven and fixed as shown in FIG.

(14) Concrete spraying operation After the set-up reinforcing bar 3a has been driven in, concrete is sprayed on the inner peripheral surface of the hole H2 in the same manner as in (4) above.
A coating layer 1b that protects 0 and prevents its collapse is formed as shown in FIG.

(15) Hard elastic body laying and fixing work A hard elastic body 5 made of a styrene foam plate is laid and fixed on the outer peripheral portion of the hole bottom plate h of the second drilling hole H2 in the same manner as in (5) as shown in FIG. I do.

(16) Assembling work of the reinforcing bar for wall reinforcement The basket-shaped reinforcing bar 18 for reinforcing the wall of the second hole is assembled along the inner periphery of the hole H2 as shown in FIG. When assembling the reinforcing bar, the vertical bar 18a is pierced into the hard elastic body 5 so as to reach the bottom of the hole, and is erected, and the vertical bar 18a is fixed to the set-up reinforcing bar 3a by welding.

(17) Assembling work of the inner formwork After assembling the reinforcing bar 18, the inner formwork 9 is placed on the hard elastic body 5 by the same method as the method (7) described above.
Assemble and fix as shown.

(18) Concrete Casting Work Concrete is poured from the casting opening 19a so as to embed the reinforcing steel bar 18 between the formwork 9 and the ground 10, and the first concrete is solidified by solidification of the concrete. A second hole wall G2 (shown in FIG. 14) integrally connected to the hole wall G1 is constructed.

Hereinafter, the same method is repeated, and concrete is successively poured in the same manner as described above while sequentially excavating and excavating holes H3 and H4 (shown in FIG. 1) having predetermined depths L3 and L4. By moving, the third hole wall G3 integrated with the second hole wall G2 and the fourth hole wall G4 integrated with the third hole wall G3
And a hole wall G for a deep foundation pile as shown in FIG. 14 is constructed.

After the perforated wall G is constructed, a reinforcing bar (not shown) for pile reinforcement is assembled in the perforated wall G, and concrete is poured and filled so as to embed the reinforcing bar for piles to support a pier. To build a deep foundation pile.

The hard elastic member 5 described in the above embodiment is used.
Is not limited to a Styrofoam plate, but it is also possible to apply a hard rubber plate or a rigid urethane foam having a predetermined thickness (for example, a thickness of about 50 mm) in which a vertical streak insertion hole is provided vertically.

[0035]

According to the method for constructing a hole wall for a deep foundation pile according to the first aspect of the present invention, a first downhole H1 having a predetermined depth L1 to be firstly excavated from the ground surface is formed with a straight hole 1 having a predetermined diameter D. The straight hole is formed as a concentrically connected hole with the diameter-enlarged countersunk hole 2 surrounded by the opening end of the straight hole. When the first hole wall G1 is constructed, concrete C is poured into the countersunk hole 2 and filled. A hole wall flange (F) integral with the first hole wall (G1) is formed, and the hole wall flange (F) has a heavy first hole in synergy with a joining force between the hole wall (G) and the ground (10). wall
Has the function to support the load of G1.

Therefore, when the hole diameter D is, for example, 10 m
Even if the diameter is large as described above and the concrete placement pitch is larger than the conventional one (for example, about 1.5 m to about 2 m), the heavy first hole wall G1 is excavated during the excavation of the second digging hole H2. The problem of falling does not occur.

Further, according to the method for constructing a hole wall for a deep foundation pile according to the second aspect of the present invention, the required number of longitudinally long members to be assembled by sequentially connecting the formwork 9 at spaced positions along the inner periphery of the hole. .. 9n, each time a hole of a predetermined depth is excavated, hard elastic bodies 5 of a predetermined thickness are annularly arranged on the outer peripheral portion of the hole bottom plate and sequentially laid and fixed. The vertical reinforcing bars 8a, 18a are pierced into the elastic body 5 to assemble the wall reinforcing reinforcing bars 8, 18..., And after the reinforcing bars are assembled, the wall reinforcing reinforcing bars 8, 18. It is characterized in that the formwork 9 is assembled, and concrete C is poured and filled between the formwork 9 and the ground 10 so as to embed the reinforcing steel bars 8, 18,.

According to this method, the work of assembling the reinforcing steel bars 8, 18... In a basket shape on the concrete casting portion can be easily performed, and the vertical reinforcing bars 8a, 18 for integrating the hole walls.
can be easily inserted only by piercing the hard elastic body 5, and the outflow of the cast concrete C can be reliably prevented by the contact of the form 9 with the elastic body 5.

Further, every time the holes H1, H2,... Of a predetermined depth are excavated, the inner peripheral surface of the holes is shaped, the setup rebar 3 is laterally fixed, and concrete is sprayed to a thickness of several tens of millimeters. When the coating layers 1a, 1b,... Which protect the ground 10 and prevent its collapse on the inner peripheral surface are formed, the ground 10 is prevented from being collapsed after the hole is excavated until the reinforcing bars 8 and the formwork 9 are assembled. It has effects such as being able to do.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing a hole wall construction method for a deep foundation pile according to an embodiment of the present invention in a state of a first excavation hole excavation step.

FIG. 2 is an explanatory diagram showing a hole wall construction method of the present invention in a state of a setup rebar driving step.

FIG. 3 is an explanatory view showing the hole wall construction method of the present invention in a state of a concrete spraying step.

FIG. 4 is an explanatory view showing a hole wall construction method of the present invention in a state of laying a hard elastic body.

FIG. 5 is an explanatory view showing the hole wall construction method of the present invention in a state of assembling a reinforcing bar for wall reinforcement.

FIG. 6 is an explanatory view showing the hole wall construction method of the present invention in an inner mold assembly step.

FIG. 7 is an explanatory view showing the hole wall construction method of the present invention in a concrete casting step.

FIG. 8 is an explanatory diagram showing a hole wall construction method of the present invention in a state of a second excavation hole excavation step.

FIG. 9 is an explanatory view showing the hole wall construction method of the present invention in a state where a hard elastic body is laid on a bottom portion of a second drilling hole.

FIG. 10 is an explanatory view showing the hole wall construction method of the present invention in an assembled state of a second hole wall reinforcing bar.

FIG. 11 is an explanatory view showing the hole wall construction method of the present invention in an assembled state of the inner formwork.

FIG. 12 is a cross-sectional plan view along the line AA in FIG. 4;

FIG. 13 is a cross-sectional plan view along the line BB in FIG. 7;

FIG. 14 is a longitudinal sectional view showing a hole wall constructed by the hole wall construction method of the present invention.

[Explanation of symbols]

H1: 1st pit, H2: 2nd pit, H3: 3rd pit, H4
... 4th drill hole, h ... hole bottom plate, 1 ... straight hole, 2 ... diametered countersink hole, 1a (1b), 2a ... cover layer, 3 (3a), 4 ... setup rebar, 5 ... hard elastic body , 8 (18) ... reinforcing bar for hole wall reinforcement, 8a (18a) ... vertical bar, 8b ... hoop bar, 9 ... inner formwork, 9a, 9b, 9c, 9n ... segment template, 10
… Ground, C… concrete, G… hole wall, G1… first hole wall,
G2: second hole wall, G3: third hole wall, G4: fourth hole wall, F: hole wall flange.

Claims (5)

[Claims] 1. A formwork having a predetermined height is used. Every time a hole having a predetermined depth is excavated, concrete is poured between the formwork and the ground, and after the concrete is solidified, the formwork is removed. In the hole wall construction method for deep foundation piles in which concrete is poured while drilling down and excavating in sequence, the first drilling hole of a predetermined depth excavated first from the ground surface A concentric hole is formed between the hole and an enlarged countersunk hole surrounded by the open end of the straight hole. Concrete is also poured into the countersunk hole at the time of constructing the first hole wall. A hole wall construction method for a deep foundation pile, wherein a hole wall flange integral with the hole wall is formed. 2. A mold having a predetermined height is used, and concrete is poured between the form and the ground every time a hole having a predetermined depth is excavated, and the mold is removed after the concrete is solidified. In a hole wall construction method for a deep foundation pile in which a concrete is lowered and excavated and excavated, and concrete is poured in sequence, the formwork is sequentially connected laterally to a separated position along the inner periphery of the hole and assembled. Each time a hole of a predetermined depth is excavated, hard elastic bodies of a predetermined thickness are arranged in a ring on the outer peripheral portion of the hole bottom plate and sequentially laid and fixed. A vertical reinforcing bar is pierced into the elastic body to assemble the reinforcing bar for the wall, and after assembling the reinforcing bar, the formwork is assembled so as to house the reinforcing bar for the wall on the elastic body, and the formwork is assembled between the formwork and the ground. The concrete is cast and filled to embed the reinforcing steel Pore walls Construction method for shinso piles characterized by. 3. A formwork having a predetermined height is used. Every time a hole having a predetermined depth is excavated, concrete is poured between the formwork and the ground, and after the concrete is solidified, the formwork is removed. In the hole wall construction method for deep foundation piles in which concrete is poured while drilling down and excavating in sequence, the first drilling hole of a predetermined depth excavated first from the ground surface A concentric hole is formed between the hole and an enlarged countersunk hole surrounded by the open end of the straight hole. Concrete is also poured into the countersunk hole at the time of constructing the first hole wall. (1) forming a hole wall flange integral with the hole wall, comprising the required number of vertically long segment template plates which are assembled by connecting the formwork to the separated positions along the hole inner circumference sequentially; Each time a hole of a given depth is excavated, a ring of hard elastic bodies of a given thickness is placed around the perimeter of the bottom of the hole and arranged sequentially. A vertical reinforcing bar is pierced into the hard elastic body to assemble a reinforcing bar for a wall, and after assembling the reinforcing bar, the formwork is assembled so that the reinforcing bar for a wall is installed on the elastic body. A hole wall construction method for deep foundation piles, where concrete is poured and filled to embed reinforcing steel for wall reinforcement between the ground and the ground. 4. A formwork having a predetermined height is used. Every time a hole having a predetermined depth is excavated, concrete is poured between the formwork and the ground, and after the concrete is solidified, the formwork is removed. In the hole wall construction method for deep foundation piles in which concrete is poured while drilling down and excavating in sequence, the first drilling hole of a predetermined depth excavated first from the ground surface A concentric hole is formed between the hole and an enlarged countersunk hole surrounded by the open end of the straight hole. Concrete is also poured into the countersunk hole at the time of constructing the first hole wall. 1 Forming a hole wall flange integral with the hole wall, every time a hole of a predetermined depth is excavated, shaping the inner peripheral surface of the hole and laterally fixing the setup rebar and spraying concrete to a thickness of several tens of millimeters By forming a coating layer on the inner surface of the hole to protect the ground and prevent its collapse, the shape of this coating layer Later, hard elastic bodies having a predetermined thickness are arranged in a ring on the outer peripheral portion of the hole bottom plate and sequentially laid and fixed. A vertical bar is pierced into the hard elastic bodies to assemble a reinforcing bar for wall reinforcement, and a wall reinforcing member is provided on the elastic body. Assembling the formwork in a form to house a reinforcing steel bar, and casting and filling concrete between the formwork and the ground to bury a reinforcing steel for wall reinforcement, Hole wall construction method. 5. The method according to claim 2, wherein the elastic body is a hard styrofoam plate.