JPH0351365Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to an improvement of an open hollow cylindrical pile.

``Conventional technology'' The cement milk method is used as a low-noise, low-vibration method for depositing ready-made concrete piles. As shown in the order of implementation in Figure 8 A to C, this construction method involves (a) excavating a hole 11 larger than the screw diameter with a continuous screw auger 10 while discharging earth and sand; This is a construction method in which a pile 12 such as C is built into a hole 11 filled with B and foot hardening solution A, and the pile is a so-called closed shoe with a closed tip. Although this construction method has the same supporting capacity as the impact construction method, it has the following drawbacks.

(1) The pile may stop at a high level, that is, the pile may not be able to penetrate into the specified support layer, and the pile may stop midway.

(2) Since a continuous screw auger is used, a large amount of soil is removed, which is expensive to dispose of.

(3) Since it is a condition to use a shoe with the tip of the pile closed, the soil removal costs incurred by inserting the pile are also large.

In this cement milk construction method, if a pile with an open bottom end is used, the liquid will also seep into the inside of the pile, and the amount of soil removed will be less than that of a blockage system, making it economical, but the effect of blockage is not clear. The current situation is that the Ministry of Construction's guidelines, ``Guidelines and Explanations for Embedded Pile Construction - Cement Milk Method'' edited by the Japan Building Center, state that the use of a blockage system is a condition.

``Problems to be solved by the invention'' This invention is a construction method that attempts to improve the drawbacks of the cement milk method as described above, namely, a method of rotating and inserting a concrete into a soiled excavation hole - a pre-boring rotational sinking method. - Create a hollow cylindrical open type pile that can be used effectively in a structure that has a good blocking effect and can obtain a large supporting capacity, and provide a pile that can be constructed economically and has an excellent supporting capacity. That is.

``Means for Solving the Problems'' The present invention is characterized in that a protrusion that protrudes into the hollow part of the hollow cylindrical pile is provided at the tip of the hollow cylindrical pile, and is integrated with the shaft reinforcing bar and concrete. It is.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIGS. 1 to 4, reference numeral 1 denotes a concrete pile main body, which is formed into a hollow cylindrical shape, and a seat plate 2 is connected to a large number of shaft reinforcing bars 3 at the open lower end.
The pile body 1 is provided integrally with the concrete, and a reinforcing plate 4 is wrapped around the outer peripheral surface of the end portion of the pile body 1. The above configuration is similar to the open type hollow cylindrical peg that has been commonly used in the past.

In the present invention, protrusions 6 are connected to the shaft reinforcing bar 3 at the lower end of the pile and are formed to protrude over a required length into the hollow part 5 at intervals in the length direction of the pile. A major feature is that it has several stages. That is, the third
As shown in FIG.
An annular plate with an inner diameter smaller than that of the hollow part 5 is used as the protrusion 6, which is connected by connecting rods 7 at intervals vertically, as shown in FIGS. 1 and 2, for example. is connected to the shaft reinforcing bar 3 and fixed by welding. This work is performed prior to centrifugal force forming of concrete. After molding, the annular plate 6 will protrude into the hollow portion by an amount whose inner diameter is smaller than the inner diameter of the hollow portion 5.

"Function" Next, an example of construction using the pre-boring rotational sinking method using the piles of the present invention will be explained with reference to FIG. 7. First, as shown in FIG. Alternating screw augers 9
The soil is stirred and excavated while water is injected from the tip of the excavator. After reaching a predetermined depth, a circumferential fixing fluid (also used as drilling fluid, cement + bentonite + water) that can be replaced with water is injected from the tip of the auger 9 and mixed with the earth and sand. After excavating to the supporting layer, the pile circumferential fixing liquid is switched to the root hardening liquid A, and while injecting a predetermined amount, the auger 9 is pulled up as shown in b. The bottom of the drilled hole is filled with soil hardening solution A.
is filled and pushed up, and the soil pile circumferential fixing liquid B is filled above the soil foot compacting liquid A, and the mixture C of water and earth and sand is filled above the pile circumferential fixing liquid B. Become. Next, the open type hollow cylindrical pile 1 of the present invention described above is sunk while rotating. This work can be easily carried out without encountering great resistance because the mixture C of water and earth and sand and the soil piling fixing liquid B permeate into the hollow part of the pile 1. Then, as shown in d, the lower end of the pile 1 is placed in a layer of soil hardening solution A for a predetermined length. In this case as well, the soil mulch liquid A will easily penetrate into the hollow part 5 of the pile 1, and the inside and outside of the lower end of the pile 1 will be fixed in the soil mulch liquid A, which will prevent blockage. A similar blocking effect will be obtained. The lower end of the pile 1 is not only surrounded by the soil mulch liquid A, but also the presence of the protrusions 6, 6 allows for a strong physical bond between the pile 1 and the soil mulch liquid A. At the same time, the supporting force of the stake 1 is significantly increased in accordance with the area of the protrusion 6 protruding into the hollow portion 5.

"Effects of the Invention" As explained above, the stake of the present invention has a protrusion that protrudes into the hollow part of the lower end of the stake.
It is possible to obtain the same effect as a block show. In other words, even if the soil foot hardening liquid that has entered the hollow part of the lower end of the pile is subjected to short-term (earthquake) overload of the pile, the movement of the outer periphery of the soil foot hardening liquid is controlled by the projections. This is because it can be designed so that the soil mulch solution does not shift inside. If the protrusions were not provided as in the present invention, it is possible that the soil footing solution would shift internally due to the overloading load, and this movement would cause vertical cracks in the pile body. Become. With the stake of the present invention, such a situation does not occur. In addition, the protrusion protruding into the hollow part of the present invention has a connecting rod provided on its outer periphery fixed to the shaft reinforcing bar, and is integrally connected to the shaft reinforcing bar and concrete, so that the connection with the concrete pile is strong and It has many advantages, such as simple structure, easy manufacturing, and low cost.

[Brief explanation of the drawing]

Fig. 1 is a half-cut side view showing an embodiment of the present invention, Fig. 2 is a half-cut bottom view of the same, Fig. 3 is a side view of the protrusion portion, Fig. 4 is a plan view of the same, and Figs. d is a side sectional view showing the construction order of the present invention pile, and FIGS. 6A to 6C are side sectional views showing the construction order of the conventional construction method. 1... Pile body, 2... Seat plate, 3... Shaft reinforcing bar,
5...Hollow part, 6...Protrusion, 7...Connecting rod, 9
...Screw Ogre.

Claims (1)

[Scope of utility model registration request] A plurality of connecting rods are installed in parallel with the axial reinforcing bars on the outer periphery of an annular plate protrusion whose outer periphery is in contact with the axial reinforcing bars arranged annularly in the concrete pile, and whose inner periphery is smaller in diameter than the hollow part of the concrete pile. the connecting rod is fixed to a shaft reinforcing bar at the tip of a concrete pile formed into a hollow cylindrical shape, and the inner peripheral part of the protrusion protrudes into the hollow part of the tip of the concrete pile formed into a hollow cylindrical shape, An open hollow cylindrical pile characterized by being integrated with shaft reinforcement and concrete.