JPS6037249B2 - How to build large long foundation piles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a comb, in particular a large long foundation that can be inserted or penetrated into the ground without hitting concrete (or steel pipe comb) or with a very small amount of impact. (Regarding the method of construction.)

Conventionally, a hole is previously formed using an auger or the like, and a steel material such as an H-shaped steel is inserted into the hole.

However, these conventional methods are essentially different from those of the type that bear the weight of permanent heavy structures such as concrete or steel pipe combs, and can also be used for other purposes than as earth retaining walls. Limited to special items. The above precedents cannot be used in the field of steel pipe combs or concrete combs. In other words, if the comb is short, there is no point in drilling holes, and even in the case of the longest comb, the penetration resistance is still excessive, and drilling the holes will reduce vibration and noise during impact. Any attempt to reduce pollution will be undermined. From this point of view, a soil pile is formed in advance by mixing cement grout and cement at a predetermined location in the ground, and in the unsolidified state of this soil pile,
However, the method of inserting and standing up the pile into this pile has become widely used as the latest method. The basic idea of this method is that the diameter of the drilled hole itself is larger than the diameter of By integrating the comb and the filler material, the comb can be supported on the ground. According to this method, the comb can be easily inserted into the soil pile without any special impact, making it useful as a vibration-free and noise-free construction method. On the other hand, if the soil pile is long, it cannot be directly supported by the ground until the soil pile becomes self-supporting, and the rake deforms and the comb easily buckles due to excessive load.This method It can be used for combs up to about 15 to 20 lengths; if the comb is longer than this, construction is extremely difficult.Also, the cement grout and ± sand can be uniformly mixed over the entire length of the hole. It has been found that it is difficult to mix soil piles, and the deformation of the soil pile as well as the variation in the strength of the soil pile adversely affects the strength of the subsequent support.The present invention solves the above-mentioned conventional drawbacks. The purpose is to

According to the method for constructing a foundation according to the present invention, an auger
, a hole is drilled in the ground using a drilling device such as a rod, and an arbitrary point within this hole is combed to form a hole with a diameter larger than the diameter of the hole, and then Inside this drilled hole,
A method is provided for constructing a foundation comb by press-fitting the comb or applying an auxiliary impact force, then combing it into the foundation ground, and driving the tip of the comb into the foundation ground. When installing the comb, the press-fitting or penetration resistance is very low, and when the horsetail enters the comb, the comb is always held and guided by the protruding ground surface.

For example, in the case of the 60 concrete combs constructed by the present applicant, they were sufficiently held by the protruding ground surfaces at the front and back of the shelves with a height of about 8 and installed at intervals of about 8 and 10 cm, respectively. It has been demonstrated that the comb sinks very smoothly due to its own weight or due to its own weight plus an auxiliary impact load. When drilling with a hole drilling machine such as an auger, any liquid material such as water or bentonite mud can be poured out from the tip of the drilling machine to soften the ground and reduce drilling resistance. In this case, if the liquid material contains a solidifying agent, the sludge-like earth and sand discharged by an auger or the like can be solidified on the ground, which is convenient from the standpoint of scarcity. In addition, after the completion of the borehole work, if materials such as pentonite mud, water, or concrete are injected into the borehole prior to installation, these materials will be press-fitted or penetrated. It is also possible that it is interposed between the ground and acts as a lubricant. If a material such as concrete or other solidifying material is injected into the borehole, it should occupy the enlarged part of the borehole after the comb is installed and quickly close the gap between the comb and the enlarged part. become.
Hereinafter, one embodiment of the present invention will be described in more detail with reference to the drawings.

As shown in FIG. 1, the method according to the present invention involves first rotating a hole drilling machine 1, such as an auger or a rod, clockwise in the illustrated example, into the ground to drill a hole with a diameter smaller than the diameter of the hole. It starts by forming 2.

After forming the hole 2, the drilling machine is rotated in reverse and gradually pulled up, and a hole-drilling portion 4 as shown in FIG. 2 is formed by the hole-drilling bit 3. The hole drilling bit is as shown in Figure 4.
It is composed of a base 7 fixed to the rotating shaft 5 of the drilling machine, and a blade 9 rotatably supported on the base 7 with a pin 11. The blade 9 of this hole expanding bit is in a closed state at the position shown by the dashed line in Fig. 4 when the drilling machine is operating in the normal direction, and is in the position shown by the solid line in Fig. 4 when the drilling machine is operating in the reverse direction. It is configured to expand. Therefore, by alternately repeating forward and reverse rotation while pulling up the drilling machine, the enlarged portion 4 and the non-expanded portion of the drilled hole are intermittently formed as shown in the second diagram. Become. During this drilling work, if water, bentonite mud, or other liquid material is poured out from the tip of the hole, the ground can be softened and the drilling resistance can be reduced. Furthermore, by mixing a solidifying agent into this liquid material, the simulated sludge-like earth and sand can be solidified on the ground, which is convenient. After completing the work, the third
As shown in the figure, install the rod in the drilled hole. This installation can be carried out using its own weight, a slight reinforcing impact load, or a press-in device. The ledge 1 that is press-fitted or penetrated into the drilled hole or the shelf-shaped protruding ground surface 6 that remains after forming the hole enlarged portion 4 allows the surrounding area to be tightly held and positioned, and at the same time prevents it from deforming due to its own weight. When the comb is driven into the supporting ground, it also holds the comb sufficiently and plays the role of preventing deformation buckling of the comb. In addition, the protruding ground surface defines a guide surface for the comb to enter during subsidence, making it possible to reliably install the comb at a predetermined vertical or inclined angle. According to the method described above, it is possible to extremely reduce press-fitting or penetration resistance even with extremely deep and long combs, and to completely prevent damage to the combs. The superiority of the present invention was recognized to be extremely remarkable, since it was only necessary to use the present invention.

Note that the method according to the present invention is not limited to the above-mentioned method.

For example, the drilling by the drilling machine 1 and the drilling by the drilling bit 3 can be performed continuously from above by alternately repeating forward and reverse rotations of the drilling machine.

[Brief explanation of the drawing]

FIGS. 1 to 3 are explanatory diagrams showing a foundation and construction method according to the present invention, and FIG. 4 is a perspective view of a hole expanding bit installed near the tip of a drilling machine. 1: Hole drilling machine, 2: Hole drilling, 3: Hole expansion bit, 4: Hole expansion part 5: Rotating shaft, 6: Protruding ground surface, 7: Base, 9: Blade, 10: Comb, 11: Pin. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Drill a hole with a diameter smaller than the diameter of the pile in the ground, then enlarge the hole at the required location to a diameter larger than the diameter of the pile to form a shelf-shaped hole that protrudes inward of the hole. The protruding ground surface, the enlarged ground surface expanded in the outward direction, and the enlarged ground surface expanded in the outward direction are alternately repeated several times over the entire length of the drilled hole, and the hardened ground surface is press-fitted into the drilled hole. Alternatively, a method for constructing large long foundation piles in which the tip of the pile is penetrated into the foundation ground by applying a supplementary impact force, and then a final blow is applied.