JPH05306520A - Formation of soil-cement composite pile - Google Patents

Abstract

PURPOSE:To raise resistance against horizontal bending moment during earthquake by forming a soil-cement composite pile with high vertical accuracy by using an SC pile on the upper end by combined use of an inner drilling pile method and a preboring method. CONSTITUTION:The auger rod 21 of an auger 20 having an excavating blade 23 and an accompanying turn-preventing blade 25 on its tip is inserted into a steel tubular pile 31 by preceding the blades 23 and 25 ahead of the tip of the pile 31. While jetting a hardening agent from the tip of the rod 21 and while turning the pile 31, the auger 20 is only advanced by a given distance rotationally. Only the pit bottom is packed with another hardening agent having a higher compressive strength than the hardening agent. After the auger 20 is pulled up, SC piles are connected and set until the tip of the steel tube reaches the bottom of the pit.

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 soil cement composite piles applied to foundation work related to construction.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application No. 2-316532 has been filed as a method for constructing a soil cement composite pile. 8 to 13 are sectional views showing the construction sequence of the method for constructing the soil cement composite pile. First, as shown in FIG. 8, drilling 10 is performed while injecting a solidifying material such as cement milk from the vicinity of the tip of the excavation / agitation rod 1. The excavation
The stirring rod 1 functions for excavation and stirring, the rod 1a is hollow, and the inside of the rod 1a serves as a flow path for the solidifying material, and a bit 3 and a stirring blade 4 are provided at the tip thereof. And a co-rotation preventing device 5 having a diameter larger than the diameter of the drilled hole is provided on the upper part thereof.
It is rotatably provided via the boss 6. A solidification material discharge hole (not shown) is provided near the tip of the rod 1a, for example, at an appropriate position of the bit 3 so that the solidification material can be ejected by being connected to the flow path in the rod 1a. .. Therefore, when the excavation / agitation rod 1 is rotated and pressed (feeding force), it is excavated by the bit 3 and agitated by the agitation blade 4 and the corotation preventive device 5, so that the inside of the drilled hole is The solidifying material is agitated and mixed to form the soil cement 2a, which is then drilled 10.

Next, when the hole 10 is drilled to a predetermined depth, the hole is stopped, and as shown in FIG. 9, the solidified material is injected so that the compressive strength after solidification is relatively larger than that of the solidified material injected until then. The material is switched to fill the bottom of the drilled hole with the solidified material 2b. However, drilling may be performed while injecting a solidified material having a relatively large strength for a distance required for root consolidation of the drilled bottom. After that, the excavation / agitation rod 1 is rotated and pulled up.

Then, as shown in FIG. 10, the bottom of the hole is
The hole 10 is filled with the solidified material 2b having a relatively high compressive strength after solidification and the other is converted into the soil cement 2a. Thereafter, as shown in FIG. 11, the hollow tube 11 having a spiral blade 121 on the outer peripheral surface of the lower end thereof is embedded in the drilled hole 10 by rotating and applying downward pressure as necessary. The spiral wing 121 of the hollow tube 11 has a predetermined width and is attached so as to extend substantially one round or more. This spiral wing 121 may be one piece or a plurality of pieces, and the one piece may have a predetermined length of not more than one round but not more than one round.

Further, the piles may be mounted in multiple stages with respect to the entire length. The hollow pipe 11 reaches the portion of the solidified material 2b having a relatively high compressive strength after solidification at the bottom of the drilled hole 10 and is embedded therein. When the length is insufficient (this is the case in most cases), the hollow tube 12 is connected and buried as shown in FIG. In this connection, the lower hollow tube 11 is supported by a clamp device 13 or the like, and the hollow tube 12 is concentrically connected to the upper side by screw connection or welding. Then, as shown in FIG. 13, the hollow pipes 11 and 12 are buried in the soil cement columns 2a and 2b in the drilled hole 10, and the construction of the soil cement composite pile is completed.

[0006]

However, the cement composite piles constructed by the above-mentioned conventional construction method are implemented by a construction method called pre-boring. That is, since the hollow pipe (pile) 11 is sunk in the soil cement column later,
The vertical accuracy of the hollow tube 11 was poor, causing misalignment.

When an earthquake occurs, a bending moment is generated at the head of a pile of a building or structure due to a horizontal force. Therefore, as shown by a chain line in the hollow pipe (pile) 12 of FIGS. 12 and 13,
S with a concrete liner inside the hollow tube
Although the C pile has been conventionally used, since the SC pile has a smaller inner diameter than the outer diameter, an auger rod is inserted into the hollow portion of the pile to feed the pile and the auger rod at the same time. The digging method could not be constructed because the auger rod could not be inserted.

The present invention has been made in view of the above-mentioned circumstances, and a cement which allows the SC pile to be arranged at the uppermost portion of the pile by using the vertical excavation method and the pre-boring method together with good vertical accuracy. A method of constructing a composite pile is provided.

[0009]

According to the method for constructing a soil cement composite pile of the present invention, an auger has at least one stabilizer rotatably fitted in the middle of an auger rod.
An excavating blade is provided at the tip of the auger rod, a stirring blade and a co-rotation preventing blade are disposed in the upper stage thereof, and the excavating blade and the stirring blade are pivotally attached to a supporting member fixed to the auger rod by a pivot, respectively. The co-rotation preventing blade is rotatably fitted to the auger rod through a supporting member and is pivotally attached to the supporting member by means of a pivot, and the excavating blade, the stirring blade and the co-rotation preventing blade are respectively attached to the supporting member by the pivot and shear pin. The auger is held in an expanded state by the above, and the auger is prepared on the ground, and has at least one spiral blade of a predetermined width, which is prepared separately, at least on the outer periphery of the lower end portion, and the spiral blade is wound for a predetermined length or more. Inserting the auger rod into the steel pipe pile with the excavation blade, the stirring blade, and the co-rotation prevention blade leading from the lower end of the steel pipe pile being rotated ahead of the lower end of the steel pipe pile; It is gripped de and steel pipe pile upper end to a respective work machine, while rotating each auger and steel pipe piles and
At the same time, while discharging the solidified material in the form of slurry from the tip of the auger, the process of feeding a predetermined number of steel pipe piles to the predetermined depth of the ground, and then stopping the rotation and feeding of the steel pipe piles and removing only the auger. While rotating, simultaneously discharging the solidified material in the form of a slurry from the tip of the auger, feeding only the auger by a predetermined distance, and then discharging the solidified material,
Switching to a slurry-like solidified material having a greater compressive strength than the solidified material discharged until then, filling the root solidification part at the bottom of the drilled hole with the solidified material, and then fixing the steel pipe pile upper end on the ground, Pull up the auger and cut the shear pin,
The process of retracting the co-rotation prevention blade, stirring blade, and excavation blade into the steel pipe pile and lifting the auger to the ground, and then adding the SC pile to the steel pipe pile whose upper end is fixed on the ground. First, the step of releasing the fixing of the steel pipe pile on the ground, grasping the upper end of the SC pile with a working machine, and inserting it into the root consolidation portion while rotating and advancing.

Further, in the method for constructing a soil cement composite pile of the present invention, in the auger, at least one stabilizer is rotatably loosely fitted in the middle of the auger rod, and an excavating blade is provided at the tip of the auger rod in the upper stage thereof. A stirring blade and a co-rotation preventing blade are provided, and the excavation blade and the stirring blade are pivotally attached to a supporting member fixed to the auger rod by a pivot, and the co-rotation preventing blade is attached to the auger rod via the supporting member. It is rotatably loosely fitted and is pivotally attached to a support member by a pivot, and the excavation blade, the stirring blade, and the co-rotation prevention blade are held in an expanded state by the support member by the pivot and shear pin, respectively. At least one spiral blade having a predetermined width, prepared on the ground and separately prepared, has at least the outer periphery of the lower end, and the spiral blade is wound for a predetermined length or more. A step of inserting the auger rod into the steel pipe pile with the excavation blade, the stirring blade, and the co-rotation prevention vane leading from the lower end of the steel pipe pile to the lower end of the steel pipe pile; Gripping, while rotating the auger and the steel pipe pile respectively, at the same time while discharging the solidified material in the form of a slurry from the tip of the auger, feeding a predetermined number of steel pipe piles while advancing to a predetermined depth of the ground, and then, While stopping the rotation and feeding of the steel pipe pile and rotating only the auger, at the same time discharging the solidified material in the form of slurry from the tip of the auger, the auger is supplied only for a predetermined distance that is shallower than the root consolidation part of the drilling bottom. And the next step, switching the discharge of the solidifying material to a slurry solidifying material having a higher compressive strength than the solidifying material discharged so far,
While discharging the solidified material from the tip of the auger, rotating and feeding only the auger by the distance of the root consolidation part at the bottom of the drilled hole, and then fixing the upper end of the steel pipe pile on the ground and lifting the auger To cut the co-rotation impeller, stirring blade and excavation blade into the steel pipe pile and lift the auger to the ground, and then add the SC pile to the steel pipe pile with the upper end fixed on the ground. The process, and then the steel pipe pile is unfixed on the ground, and the top of the SC pile is gripped with a working machine to rotate it.
And a step of inserting into the root consolidation portion while feeding.

[0011]

[Operation] When the auger is pulled out from the pile, the SC pile is not added to the uppermost portion, so the auger can be pulled out.

[0012]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 1 to 7 are half cross-sectional views showing the construction sequence of an embodiment of the present invention. In the figure, 20 is an auger, which is an auger shaft 21, a stabilizer 22 loosely fitted in the auger shaft 21, an excavating blade 23 attached to the tip of the shaft, and a stirring blade 24 fixed to the upper stage.
And a co-rotation preventing blade 25 rotatably fitted in the upper stage.

A bit 23a is fixed to the excavation blade 23,
The outer diameter of the stirring blade 24 is substantially the same as the outer diameter of the excavation blade 23 and is slightly larger than the outer diameter of the steel pipe pile. The outer diameter of the co-rotation prevention blade 25 is formed to be larger than that of the excavation blade 23, and the excavation blade 23 is formed during excavation.
Since it penetrates into the outer ground from the hole-drilling wall, the co-rotation preventing blade 25 does not rotate even if the excavating blade 23 and the stirring blade 24 rotate.

In the figure, the co-rotation prevention blade 2 is provided above the stirring blade 24.
5, the stirring blade 24 and the co-rotation prevention blade 25 are provided.
The positions of may be replaced. The co-rotation prevention wing 25,
This is for crushing a large clod produced by excavation by the excavation blade 23. The large clod rotating with the excavation blade 23 and the stirring blade 24 corresponds to the non-rotating co-rotation prevention blade, and the excavation blade 23 and the stirring blade 24. It is sheared and crushed in between to enable uniform kneading of the solidified material and the ground. 23b, 24b,
Reference numeral 25b is a bolt that pivotally supports the excavation blade 23, the stirring blade 24, and the co-rotation prevention blade 25, and is pivotally attached to the support member.

The excavating blade 23, the stirring blade 24, and the co-rotation preventing blade 25 are pivotally supported by the bolts 23b, 24b, 25b so as to be rotatable downward, and are not pivoted downward by shear pins (not shown). Is regulated by. Two
2 is a stabilizer, and a plurality of sets are loosely fitted in the middle of the auger rod 21, and a steel pipe pile to be inserted (reference numerals 31, 3 in the figure).
It comes in sliding contact with the inside of 2). The stabilizer 22 prevents the runout of the steel pipe pile during excavation and prevents the auger rod 21 from bending.

At least one spiral blade 31a having a predetermined width is provided on the outer periphery of the lower end portion of the steel pipe pile 31, and the spiral blade 31a is wound for a predetermined length or more. A plurality of the spiral blades may be provided on the steel pipe pile 31, or may be provided on the steel pipe pile added to the upper portion thereof.

The construction sequence will be described below. First, the expanded auger 20 is set on the steel pipe pile 31 on the ground. Excavation blade 23, stirring blade 24, and co-rotation prevention blade 25
The auger rod 21 is inserted into the steel pipe pile 31 in a state where the lower end of the steel pipe pile 31 precedes.

Next, an upper end of each of the auger rod 21 and the steel pipe pile 31 is grasped by a working machine (not shown), and
As shown in FIG. 2, while rotating the auger 20 and the steel pipe pile 31 in mutually opposite directions or in the same direction, at the same time, a slurry-like solidified material is discharged from a discharge port (not shown) at the tip of the auger rod 21 and Is drilled by the excavation blade 23. The ground soil mass excavated by the excavation blade 23 is crushed by the co-rotation prevention blade 25, and is mixed with the solidifying material discharged from the discharge port while being stirred by the stirring blade 24.

After one steel pipe pile 31 has been fed as shown in FIG. 2, one steel pipe pile 32 and one auger rod 21 are replenished as shown in FIG. Next, as shown in FIG. 4, one jointed piece is drilled while pouring a solidifying material, and although not shown, steel pipe piles are successively spliced to successively pour the solidifying material to a predetermined depth. When the tip of the excavation blade 23 reaches a predetermined depth, the steel pipe pile 32 is stopped from being fed, the auger 20 is rotated, and at the same time, the slurry-like solidifying material is discharged from the tip of the auger and the auger is fed for a predetermined distance. Proceed. Next, the discharge of the solidifying material is switched to a slurry solidifying material whose compressive strength after solidification is larger than that of the solidifying material injected until then, and the bottom of the drilled hole is filled with the solidifying material to form the root solidification portion 40. In this case, the auger 20 is not fed, but it is better to rotate it. This process is called a root consolidation process.

Instead of the consolidation step, after drilling to a depth of the ground shallower than the predetermined depth shown in FIG. 4 by the distance of the root consolidation portion 40 at the bottom of the drilling hole, the solidification material injected until then is drilled. It is also possible to switch to a solidified material having a high compressive strength after solidification, and to drill a hole to a predetermined depth while injecting the solidified material by the distance of the root solidification portion 40 at the bottom of the drilled hole.

In this case, after the hole is drilled to a depth of the ground which is shallower than the predetermined depth by the distance of the root consolidation portion 40 at the bottom of the hole, the solidified material having a higher compressive strength after solidification than the solidified material injected until then. , And the auger 20 is rotated and fed while injecting the solidified material by a distance 40 (hereinafter referred to as a solidification distance) of the root consolidation portion at the bottom of the drilled hole to reach a predetermined depth, and then the solidified material is injected. Alternatively, the auger rod 21 may be rotated up and down by the consolidation distance while the auger rod 21 is being rotated to perform re-stirring.

Next, as shown in FIG. 5, the upper end of the steel pipe pile 32 is fixed by a ground clamp device 50, and the auger 20 is lifted to the ground. In this case, the co-rotation preventing blade 25, the stirring blade 24, and the excavating blade 23 sequentially hit the lower end of the steel pipe pile 31 during the lifting operation, and the shear pin (not shown) is sequentially sheared. The bolts 23b, 24b, 25b pivotally supporting these members are folded downward to ascend in the steel pipe piles 31, 32.

Next, as shown in FIG. 6, an SC pile 33 is added above the steel pipe pile 32 whose upper end is fixed on the ground.

Next, as shown in FIG. 7, the steel pipe pile 32 is unfixed on the ground, the upper end of the SC pile 33 is gripped by a working machine (not shown), and the tip is sunk into the rooting portion 40 while rotating and feeding. To do.

[0025]

According to the present invention described in detail above, the following effects are exhibited. (1) In the soil cement composite pile according to the construction method of the present invention, except for one SC pile, the steel pipe piles below the pile are constructed by the medium excavation method, so that the vertical accuracy is good and there is no misalignment.

(2) Since the SC pile is used at the top,
Strong against bending moment due to horizontal force when an earthquake occurs.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a construction sequence of an embodiment of the present invention.

FIG. 2 is a half sectional view showing a construction sequence of an embodiment of the present invention.

FIG. 3 is a half cross-sectional view showing a construction sequence of an embodiment of the present invention.

FIG. 4 is a half sectional view showing a construction sequence of an embodiment of the present invention.

FIG. 5 is a half cross-sectional view showing the construction sequence of the embodiment of the present invention.

FIG. 6 is a half cross-sectional view showing the construction sequence of the embodiment of the present invention.

FIG. 7 is a half cross-sectional view showing the construction sequence of the embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a construction sequence of a conventional method for constructing a soil cement composite pile.

FIG. 9 is a cross-sectional view showing a construction sequence of a conventional method for constructing a soil cement composite pile.

FIG. 10 is a cross-sectional view showing a construction sequence of a conventional method for constructing a soil cement composite pile.

FIG. 11 is a cross-sectional view showing the construction sequence of a conventional method for constructing a soil cement composite pile.

FIG. 12 is a cross-sectional view showing the construction sequence of a conventional method for constructing a soil cement composite pile.

FIG. 13 is a cross-sectional view showing a construction sequence of a conventional method for constructing a soil cement composite pile.

[Explanation of symbols]

 20 Auger 21 Auger Rod 22 Stabilizer 23 Excavation Blade 24 Stirring Blade 25 Co-rotation Prevention Blade 23b, 24b, 25b Bolt 31, 32 Steel Pipe Pile 31a Spiral Blade 33 SC Pile 40 Rooting Part 50 Clamping Device

Claims (2)

[Claims] 1. A method for constructing a soil cement composite pile comprising the following steps. (A) In the auger, at least one stabilizer is rotatably loosely fitted in the middle of the auger rod, a drill blade is provided at the tip of the auger rod, and a stirring blade and a co-rotation preventive blade are provided above the auger rod. The blade and the stirring blade are pivotally attached to a supporting member fixed to the auger rod by a pivot, and the co-rotation preventing blade is rotatably fitted to the auger rod through the supporting member and is pivotally attached to the supporting member. The excavating blade, the stirring blade, and the co-rotation preventing blade are pivotally attached, and are supported in a spread state by a pivot and a shear pin on a supporting member, respectively, and the auger is prepared on the ground and separately prepared, and at least a predetermined width. At least one spiral blade is provided on the outer periphery of the lower end portion, and the excavation blade, the stirring blade, and the co-rotation prevention blade are made of steel from the lower end of the steel pipe pile on which the spiral blade is wound for a predetermined length or more. Inserting the auger rod into the steel pipe pile with the pipe pile lower end ahead (B) The work machine grips the auger rod and the steel pipe pile upper end, respectively, while rotating the auger and the steel pipe pile respectively, and at the same time the auger tip While discharging the solidified material in the form of slurry from the above, while feeding a predetermined number of steel pipe piles to advance to a predetermined depth in the ground (C) Next, stop the rotation and advance of the steel pipe piles and rotate only the auger. At the same time, while discharging the solidified material in the form of a slurry from the tip of the auger at the same time, the step of feeding only the auger by a predetermined distance (D) Next, the solidified material is discharged at a compressive strength higher than that of the solidified material discharged until then. Switching to a large slurry solidifying material, the step of filling the root consolidation part of the drilled hole bottom with the solidifying material (E) Next, the steel pipe pile upper end is fixed on the ground, the auger is pulled up and the shear pin is cut, Step of retracting impellers, stirring blades and excavation blades inside the steel pipe pile and lifting the auger to the ground (F) Next, adding SC pile to the steel pipe pile whose upper end is fixed on the ground (G) Next, the process of unfixing the steel pipe pile on the ground, inserting the top end of the SC pile with a working machine into the root consolidation part while rotating and advancing. 2. A method for constructing a soil cement composite pile, which comprises the following steps. (A) In the auger, at least one stabilizer is rotatably loosely fitted in the middle of the auger rod, a drill blade is provided at the tip of the auger rod, and a stirring blade and a co-rotation preventive blade are provided above the auger rod. The blade and the stirring blade are pivotally attached to a supporting member fixed to the auger rod by a pivot, and the co-rotation preventing blade is rotatably fitted to the auger rod through the supporting member and is pivotally attached to the supporting member. The excavating blade, the stirring blade, and the co-rotation preventing blade are pivotally attached, and are supported in a spread state by a pivot and a shear pin on a supporting member, respectively, and the auger is prepared on the ground and separately prepared, and at least a predetermined width. A steel pipe having at least one spiral blade at the outer periphery of the lower end, and the excavation blade, the stirring blade, and the co-rotation prevention blade from the lower end of a steel pipe pile in which the spiral blade is wound for a predetermined length or more. Step of inserting the auger rod into the steel pipe pile in a state in which it precedes the lower end of the pile (B) Have the working machine grip the auger rod and the upper end of the steel pipe pile, respectively, and rotate the auger and the steel pipe pile respectively, and simultaneously from the auger tip. Step of discharging a solidified material in a slurry state and feeding a predetermined number of steel pipe piles to a predetermined depth in the ground (C) Next, while stopping the rotation and feeding of the steel pipe piles and rotating only the auger At the same time, while discharging the solidified material in the form of slurry from the tip of the auger, the step of feeding only the auger by a predetermined distance shallower than the distance from the root consolidation portion at the bottom of the drilled hole (D) Switch to a slurry solidified material that has a greater compressive strength than the solidified material discharged to
While discharging the solidified material from the tip of the auger, rotating and feeding only the auger by the distance of the root consolidation part at the bottom of the drilled hole (E) Next, fix the upper end of the steel pipe pile on the ground and lift the auger Step of cutting the shear pin, retracting the co-rotation prevention blade, stirring blade and excavation blade into the steel pipe pile and lifting the auger to the ground (F) Next, attach the SC pile to the steel pipe pile with the upper end fixed on the ground. Step of adding (G) Next, the step of unfixing the steel pipe pile from the ground, inserting the top end of the SC pile with a working machine, and inserting into the root consolidation part while rotating and feeding.