JP2018145700A - Construction device and construction method of pile foundation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce as much as possible surplus soil including a solidifying agent that is produced when a foundation pile is constructed.SOLUTION: A construction device of a pile foundation comprises a solidifying agent injection port and a drilling blade (2) on the lower end of a rotatable bit shaft. A movable blade (3) that can sway and a stopper limiting the swaying range of the movable blade (3) are provided above the drilling blade (2) on the lower end of the rotatable bit shaft. Preferably, a length of the movable blade (3) is up to a length near the radius of a drilled hole. Furthermore, it is preferable that at least one drilled hole expansion plate (6) is used together.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an apparatus for constructing a pile foundation and a construction method thereof.

  The conventional pile foundation construction method is generally as follows as described in Patent Documents 1 and 2 below (see FIGS. 4 and 5).

  The spiral blade and the auger shaft a are caused to enter the ground by the rotation of the auger shaft a that moves up and down along the leader c attached to the auger excavator b. At the same time, the auger shaft a is rotated and a solidified material (eg, cement milk) is press-fitted into the ground from the solidified material inlet d. When the planned depth is reached, the pile foundation is constructed in the upward direction from the ground while mixing and stirring the soil and the solidified material at a predetermined speed while rotating the auger a. The direction of rotation of the auger shaft a is right rotation (forward rotation) when entering the ground, and left rotation (reverse rotation) when pulled out.

Japanese Patent Laid-Open No. 7-138937. Japanese Patent Application Laid-Open No. 11-131469.

  In the conventional pile foundation construction method described above, the following problems are known.

  The pile foundation is formed in the ground by pressurizing and discharging the solidified material from the tip inlet d of the auger shaft a and stirring it with the soil. In this case, it was inevitable that a large amount of soil mixed with the solidified material was blown out on the ground due to an increase in the volume of the soil by stirring the soil and an increase in the volume of the injected solidified material.

  In this way, the remaining soil mixed with solidified material blown up to the ground rises like a mountain on the ground surface. This pile of remaining soil was not used for ground improvement, but wasted, but also became an industrial waste, and it was uneconomical to generate new costs for its removal and disposal.

  The object of the present invention is to reduce the residual soil mixed with the solidified material as much as possible.

  A pile foundation construction apparatus according to the present invention is a pile foundation construction apparatus including a solidified material injection port and a drilling blade at a lower end portion of a rotating excavation shaft, and above the drilling blade at the lower end portion of the drilling shaft. Further, the movable wing capable of swinging and a stopper for limiting the swing range of the movable wing are provided (claim 1).

  Preferably, the length of the movable blade is set to a length close to the radius of the excavation hole.

  Preferably, the stopper is provided with an adjusting device for adjusting the swing range of the movable blade to adjust the amount of reduction of the generated residual soil (Claim 3).

  Preferably, the construction apparatus is used in combination with at least one swingable excavation hole expansion plate (Claim 4).

  The pile foundation construction method of the present invention includes a step of rotating the excavating blade located at the lower end portion by rotating the excavating shaft to infiltrate the excavating shaft into the ground, and injecting the solidified material from the solidified material inlet. And a step of pressing the solidified material downward with a movable movable blade above the excavating blade, and a step of restricting a swing range of the movable blade with a stopper. Claim 5).

  According to the pile foundation construction apparatus of the present invention and the construction method of the fifth aspect, the following effects can be obtained.

  Since the solidified material and the improved soil mixed with the solidified material are pressed and compressed downward by the movable blades and do not overflow to the ground surface, the solidified material can be used 100%. As a result, no industrial waste is generated, the ratio of the solidified material to the soil volume is increased, and the improved soil itself is consolidated, so that a strong pile foundation can be constructed.

  Since the solidified material does not overflow to the ground surface, there is no pile of residual soil mixed with the solidified material on the ground surface, so there is no need to carry it out, and there is no cost for discarding waste. Is possible.

  Since the solidified material does not rise to the ground surface, the ground surface is not contaminated with muddy water, and an orderly and favorable environment can be maintained.

  According to the method of claim 2, the pressing compression force can be utilized to the maximum by the movable blade.

  According to the method of claim 3, the amount of generated residual soil can be adjusted to the stopper by the adjusting device that adjusts the swing range of the movable blade. As a result, it is possible to adjust the swing range of the movable blade according to the ground conditions such as soil quality.

  According to the method of claim 4, by using the rocking excavation hole expansion plate in combination, the excavation hole is expanded and the coagulant can be more effectively prevented from being blown to the ground surface.

It is a front view of the pile foundation construction apparatus by the example of the present invention. It is a side view of FIG. It is explanatory drawing of the construction state of the pile foundation of a present Example. It is explanatory drawing of the construction apparatus of the conventional pile foundation. It is explanatory drawing of the construction state in the apparatus of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, an excavation shaft 1 serving as a rotation shaft is attached in parallel to a leader (c of FIG. 4) of an excavator (b of FIG. 4). The excavation shaft 1 is rotated by a motor (e in FIG. 4). A drilling blade 2 having a bit 21 is attached to the lower end of the drilling shaft 1. A coagulant injection port 22 (same as d in FIG. 4) is opened near the lower end center of the bit shaft 7.

  When constructing the pile foundation in the ground, the excavation shaft 1 is rotated by the rotation of the motor, and the ground is excavated by the excavating blades 2 arranged at the lower end while injecting the solidified material from the inlet 22, and the entire excavator is grounded. Invade inside.

  An axial core 31 is provided slightly above the excavating blade 2 in parallel to the excavating blade 2, and the movable vane 3 is attached around the axial core 31. The movable blade 3 can swing like a hinge around the shaft core 31 by its own weight or earth pressure received by the rotation of the bit 21. The movable blade 3 extends from the shaft core 31 only to one side toward the length slightly closer to the radius of the drill hole toward the slightly upper side of the drill blade 2.

  Several stoppers 4 (four in FIG. 2) extend like a claw at regular intervals above and below the movable wing 3. The swing range of the movable blade 3 in the vertical direction is restricted by the stopper 4. An adjustment screw 41 is attached to the stopper 4 so that the swing range can be adjusted.

  The movable wing 3 hangs down by its own weight in a natural state, contacts the lower stopper 42 or the adjusting screw 41, and does not move further downward. However, as shown in FIG. 3, when the auger shaft a is rotated in the reverse direction, this time, it contacts the upper stopper 43 or the adjusting screw 41 and does not move further upward. At this position, the movable blade 3 constantly presses the soil 10 mixed with the solidified material downward.

  Since the surface of the movable wing 3 presses the improved soil 10 mixed with the solidified material downward, the pressing effect becomes larger when the pressing surface (the surface of the movable wing 3) has as much resistance as possible. On the other hand, the greater the resistance of the pressing surface, the lower the excavation ability when entering the ground. In the present invention, by making the movable blade 3 swing, the resistance becomes small when entering the ground, and a large resistance can be given when the improved soil is pressed.

  Above the movable blade 3, a plurality of stirring blades 5 (52, 53) and a stirring blade 51 for preventing co-rotation are provided. The agitating blade 5 and the agitating blade 51 are for crushing the excavated soil that has become a lump, and a plurality of rod-shaped steels project in the outer circumferential direction, and the lump is broken by the rod-shaped blades to break up the lump. Mix and stir the solidified material.

  Further, a rocking excavation hole expansion plate 6 is provided above the stirring blade 5. The excavation hole expanding plate 6 partially protrudes in the outer circumferential direction, has an axial center 62 in the middle, and its swinging range is limited by a stopper 63. Since the excavation hole expansion plate 6 is slightly longer than the agitating blades 5 (52, 53) and the excavation blade 2, the outer peripheral soil of the hole wall that has not been excavated is pressed outward to expand the hole wall. Further, since it does not contact the outer peripheral surface of the hole wall perpendicularly by swinging, it can be pressed without scraping the soil on the outer peripheral portion of the hole wall.

  Next, a method for forming a pile foundation using the above apparatus will be described.

  The excavation shaft 1 is rotated by a motor, and the excavation shaft 1 is rotated to rotate the excavation blade 2 at the lower end. The ground is excavated by the bit 21 attached to the excavation shaft 1 to enter the ground.

  Simultaneously with the excavation by the excavation blade 2, the solidified material is injected into the excavation hole 9 from the tip of the excavation shaft 1. In the embodiment, cement milk is used as a solidifying material.

  The excavated soil is agitated by the plural agitating blades 5 (52, 53) and the excavating blades 51.

  Further, since the unexcavated raw soil is pushed away in the outer peripheral direction by the swingable excavation hole expansion plate 6, an excavation hole 9 having a larger diameter is formed.

  When the excavating blade 2 is reversed, the movable blade 3 rises due to the resistance of the soil, hits the upper stopper 43 and cannot move further upward, so the soil 10 mixed with solidified material is constantly pressed downward and compressed. .

  Furthermore, as a result of using the excavation hole expansion plate 6 together, the soil mixed with the cement milk is filled into the excavation hole 9 without the need to apply a large pressure, as much as the raw earth and sand are pushed outward.

  As a result of using the movable blade 3 and the excavation hole expansion plate 6, especially the former, the earth and sand 10 mixed with the solidified material and the excavated soil overflows to the ground surface as in the conventional case, or the pile of the residual soil 10 mixed with the solidified material is generated. Things like excitement are less likely to occur.

  When the planned excavation is completed, the excavation shaft 1 is pulled out from the excavation hole 9. When pulling out, it is usually pulled out while rotating in the opposite direction to excavation.

DESCRIPTION OF SYMBOLS 1 Excavation shaft 2 Excavation blade 21 Bit 22 Solidified material injection port 3 Movable blade 31 Axle core 4 Stopper 41 Adjustment screw 42 Lower stopper 43 Stopper 43 Upper stopper 5 (52, 53) Stirring blade 51 Co-rotation prevention stirring blade 6 Swing Possible drilling hole expansion plate 7 Bit shaft 9 Drilling hole 10 Soil mixed with solidified material (cement milk) a Auger shaft b Auger excavator c Leader d Solidified material inlet
e motor

Claims (4)

A pile foundation construction device comprising a solidified material inlet (22) and a drilling blade (2) at the lower end of a rotating bit shaft (7),
A swingable movable blade (3) and a stopper (4) for limiting the swing range of the movable blade (3) are provided above the excavating blade (2) at the lower end of the bit shaft (7). A pile foundation construction device characterized by that.   The construction device according to claim 1, wherein the movable blade (3) extends to a length close to the radius of the excavation hole (9).   3. The device according to claim 1, wherein at least one rocking drilling hole expansion plate (6) is used in combination. A pile foundation construction method,
Rotating the excavating blade (2) located at the lower end by rotating the bit shaft (7) and intruding the bit shaft (7) into the ground;
Injecting the solidified material from the solidified material injection port (22);
A step of pressing the solidified material or the soil mixed with the solidified material downward by the swingable movable blade (3) above the excavating blade (2);
And a step of restricting the swing range of the movable wing (3) with a stopper (4).