JPS6030715A - Concrete foundation pile - Google Patents

Abstract

PURPOSE:To raise the performance of a concrete fundation pile as a friction pile and also as a bearing pile by a method in which the lower end portion of a cylindrical pile body is expanded into a conical form, and plural knots of the same diameter as the maximum diameter of the conical portion are provided at adequate intervals to the pile body. CONSTITUTION:The torso portion of a foundation pile 1 is shaped into a cylindrical form, and the lower end portion 4 of the pile 1 is expanded into a nearly truncated conical form to form a bottomed or cylindrical lower part. Knots 3 provided to the pile body 2 have a shape such as to increase the friction force between the ground 6 and the foundation pile 1 when broken stone or gravel 5 is packed into the aperture between the ground 6 and the foundation pile 1. The lump 3 also has an abacus beads form of nearly 45 deg.-angled upper and lower faces. For this reason, the performance of the foundation pile as a bearing pile can thus be raised since the friction force between the ground and the pile is greatly raised by the lumps.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to reinforced concrete foundation piles for architecture and civil engineering.

By the way, the long-term permissible bearing capacity of concrete foundation piles P, (tt゛)
is generally expressed by the following formula, α: Pier tip bearing capacity coefficient (for the driving method, α = ao
sFor embedded method piles, α = 20%, and some construction methods are approved with α = 25) D is the diameter of the pile) Ns; N value of sandy soil LB; pile length in sandy soil (m ) qu; unconfined compressive strength of cohesive soil (ts°/-) Lo; cohesive soil Pile length (m) φ;〈Pile circumference (φ=πD) (m) In other words, the PI term in [] is determined by the ground N value and bottom area Ap, and is based on the properties of the so-called support pile. This is related. , and the second term in % is the pile circumference ψ, soil quality, and embedment length ζL.
8. This relates to the properties as a friction pile due to Lc.

In conventional construction, the piles are connected to high-quality ground with a high N value and driven long, or after driving the piles, the tip of the pile is excavated widely and cement milk is injected to create a bulb-shaped pile. Generally, methods such as increasing the support area by In other words, it was an attempt to take advantage of the characteristics of the support pile described in the first paragraph, but when trying to make a bulb-shaped one, the surrounding ground became loose, and even when cement milk was poured, the value of α remained extremely high at 25 or close to 20. The reality is that it has no choice but to become uneconomical. An example of this is Japanese Patent Publication No. 40-8864.

- Improvements to piles with various joints placed on the piles include Utility Model Publication No. 27-3748, No. 3
No. 0-5341, No. 39-9825% No. 39-3556
No. 9, No. 43-11982, and No. 44-27642, but consideration has been given to support for the end of the pile due to consideration for driving, such as reducing the size of the end of the pile.

In addition, in recent years, it has been pointed out that the uneconomical design concept of driving piles into deep, strong ground is one that is too biased toward the support piles, and friction piles that allow for a certain amount of settlement have been reconsidered. In view of these circumstances, the present invention aims to provide a reinforced concrete foundation pile for architecture and civil engineering that simultaneously improves the performance as a support pile and as a friction pile.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained below based on the drawings.

1 to 5 show embodiments of the present invention, l is a reinforced concrete foundation pile for architecture and civil engineering, and this foundation pile l has a pile main body 2 and a predetermined interval between the pile main bodies 2. The trunk of the foundation pile I is a cylindrical body, and the lower end 4 of the P foundation pile I is expanded into a substantially truncated female body with a bottom or a cylindrical body. In addition, the shape of the crushed portion 4 of this pile main body 2 may be any shape as long as it increases the above-mentioned supporting area Ap, and as mentioned above, it may be formed into a substantially truncated conical shape. Field = 2.25 times.

In addition, the joints 3 arranged on the pile body 2 are made of crushed stone or gravel 5.
The joint 3 is formed in a shape that increases the frictional force between the ground and the foundation pile 1 when it is press-fitted into the gap between the ground 6 and the foundation pile 1.This joint 3 is similar to the joint 3a shown in FIG. The diameter may be approximately the same as the maximum diameter of the truncated cone, and the upper and lower surfaces may be cut at an angle of approximately 45° to form a solo pan shape.
Like the joints 3b shown in the figure and FIG.
It is formed by being displaced.

Further, it is preferable that the segments be provided at intervals of about 1 m, for example.

The pile body 1 is made of the same cylindrical body or a cylindrical body with a bottom, and the upper and lower surfaces of the pile body 2 have a diameter larger than that of the pile body 2 at the bottom of the pile body 2.
Solo pan spherical segments 3ai are arranged at an angle of 180°, and the other segments 3b are approximately triangular in shape with approximately the same diameter as the segments 3a, and are displaced 180° every other segment.

As shown in Fig. 1, the foundation pile 1 of the present invention is driven into the excavated ground 6, and at the same time, the gap between the ground 6 and the foundation pile 1 is evenly filled with crushed stone or gravel 5 all around the circumference. Ru.

According to the present invention described above, by enlarging the lower end of the pile body into a truncated cylindrical body, the performance as a support pile is improved as described above, and the frictional force between the ground and the pile is significantly improved by the joints. , the performance as a friction pile is improved at the same time.

By arranging the joints, the frictional force increases by at least D/d, and improvements in *NB and qu can also be expected.

Another segment? When the piles are approximately triangular in shape and arranged with a displacement of 1800 degrees every other pile, it becomes easy to press in crushed stone or gravel, and it also becomes possible to fill the entire circumference of the pile with crushed stone or gravel evenly. Ta.

In addition, when piles are driven, crushed stones, gravel, etc. are placed around them, and the protrusions of the joints are created by antibodies.
Since these gravels and crushed stones can be inserted into the space created between the main body and the convexity, the surrounding ground is improved, and at the same time, it is possible to exert a frictional force of the same diameter as the diameter of one segment.

Therefore, even on somewhat soft ground, it can exhibit many times the bearing capacity of conventional piles, making it an economically superior invention.

In addition, in conventional piles, the improvement of the supporting force at the lower end was limited to improving only the supporting force at the lower end, and the improvement in frictional supporting force was limited to partial improvements, but in the present invention, these improvements have been made in one. This makes it possible to dramatically improve the bearing capacity of piles.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention; Fig. 1 is a state diagram when the foundation pile is press-fitted into the ground, Fig. 2 is a front view of the foundation pile with the lower end enlarged, and Fig. 3 is a front view of another foundation pile,
Figure 4 is a front view of another implementation of the foundation pile shown in Figure 2.
The figure is a sectional view taken along the line AA in FIG. 3. Applicant: Fujimura - Husband

Claims (1)

[Scope of Claims] (1) A concrete foundation pile consisting of a plurality of joints having approximately the same diameter as the lower end of the pile main body, which is a cylindrical body or a cylinder with a bottom. The concrete foundation pile according to claim 1, which is formed into a solopan spherical shape by cutting at an angle of about 45°. (3) The joint is formed into a substantially triangular shape, and A concrete foundation pile according to claim 1, in which every other joint is displaced by 180 degrees. In addition to arranging joints with a diameter larger than the diameter of the Solopan spherical pile body cut at an angle of approximately 45 degrees,
The other joints are formed into a substantially triangular shape with approximately the same diameter as the solopan spherical joint, and a plurality of the approximately triangular joints are arranged with a displacement of K18oo every other concrete foundation pile,