JPH0617414A - Drainage reinforcement pile - Google Patents

Abstract

PURPOSE:To prevent effectively a tension fracture produced by liquidization of sand ground bed in earthquake not only to prevent residual sink after earthquake, but also to cope effectively with the existing structures such as tank, river bank, banking, buried object, semi-underground structure, etc. CONSTITUTION:A deformed PC bar 4a with uneven surface of approx. 150mm of node for an inner diameter of 100mm is positioned in an oval hole drilled in the ground 1, and crushed stones 4b of below approx. 25mm are filled tightly around it, to construct a pile of a diameter of approx. 250mm. Because the crushed stones 4b are engaged with a sand ground 1 around it an also engaged with the deformed PC bar 4a, when a tension is applied to the ground 1, the tension is transmitted to the deformed PC bar 4a through the crushed stones 4b. As a result, the deformed PC bar 4a resists the tension of the ground 1. The compressive force of the ground 1 also receives a resistance by the deformed PC bar 4a and crushed stones 4b. Because a space exists between the crushed stones 4b, space water in the surrounding ground bed 1 is absorbed in it, rises, and collected to a water collecting reservoir 5 on the surface of the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drainage reinforcing pile having a drainage function for preventing tensile failure of sandy ground.

[0002]

2. Description of the Related Art As a conventional sandy ground improvement method, a sand compaction method, a gravel compaction method,
There were vibro flotation method, deep mixing method and sheet pile method.

However, the gravel compaction method is expected only for the drainage effect, and the sand compaction method and the vibro flotation method have only the effect of simply compacting the sandy ground.
Only vertical placement was possible.

Further, the above-mentioned deep layer mixing treatment method is only a method of simply hardening the ground with an improving agent such as cement,
If it is used on sandy ground, a defective work may occur, and the load may concentrate and break at the defective work part during an earthquake. Furthermore, the sheet pile construction method was only a temporary fastening method.

Moreover, except for the above-mentioned sheet pile construction method, only the newly constructed ground can be improved, and when the sandy ground is liquefied by the earthquake and tensile force acts on the ground and the ground is destroyed, gravel piles and sand piles However, there is a problem that there is no force that resists the tensile force.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art, and the purpose of the present invention is to make tensile breakage of ground caused by liquefaction of sandy ground during an earthquake. Not only can prevent residual settlement after an earthquake, but also can effectively deal with existing structures such as tanks, river levees, embankments, buried objects, and semi-underground structures. To provide drainage reinforcement piles.

[0007]

The drainage reinforcement pile of the present invention comprises:
Characterized by arranging a deformed PC rod having an uneven surface in a long hole drilled in the sandy ground and densely filling crushed stones in the gap between the deformed PC rod and the long hole And again
Inside the long hole drilled in the sandy ground, basket rebar consisting of several main bars and hoop bars is arranged, and the gap between the basket bar and the long hole is densely filled with crushed stone. Characterize.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is a sandy ground in which a buried object 2 such as a box-type buried pipe and a semi-underground structure 3 such as an excavated road are constructed.

In the liquefaction risk area A of the ground surrounding these buried objects 2 and semi-underground structures 3, the small diameter drainage reinforcement pile 4 of the present invention is laid in the inclined direction or the vertical direction with respect to the ground surface. Has been done.

The upper end of the drainage reinforcement pile 4 is exposed on the ground surface and is connected to the water collecting mass 5. Therefore, the pore water absorbed by the drainage reinforcement pile 4 and rising is
The water is collected in the water collecting mass 5 and drained. The upper end portion of the drainage reinforcement pile 4 is fixed to the surface ground by means of ground fixing means such as concrete cement.

The structure of the drainage reinforcement pile 4 is, for example, as shown in FIG. 2, an inner diameter of 100 in a long hole drilled in the ground 1.
Deformed PC with an uneven surface with a node diameter of 150 mm in mm
A bar 4a is placed around the crushed stone 4 of about 25 mm or less.
b is densely packed and has a pile diameter of about 250 mm.

Therefore, the crushed stone 4b is the sandy ground 1 around it.
Since the deformed PC rod 4a also meshes with the deformed PC rod 4a, for example, when a tensile force acts on the ground 1, this tensile force is transmitted to the deformed PC rod 4a via the crushed stone 4b. Resists the tensile force of the ground 1. Further, the compressive force of the ground 1 is also resisted by the deformed PC rod 4a and the crushed stone 4b.

Further, since there are voids between the crushed stones 4b, pore water in the surrounding ground 1 is absorbed and rises therein, and is collected by the water collecting mass 5 on the surface of the ground.

Furthermore, by mounting the drainage reinforcement pile 4 of the present invention in an inclined state with respect to the ground surface, for example, in the case of an earthquake, vibration in either the vertical direction or the horizontal direction is generated. The horizontal or vertical compressive force and the tensile force act on the drainage reinforcing pile 4 as a compressive component and a tensile component in the inclined axial direction of the drainage reinforcing pile 4, and the drainage reinforcing pile 4
Receive the resistance of.

FIG. 3 shows an embodiment of the second invention.
For example, in the small-diameter long hole drilled in the sandy ground 1,
A cage rebar 4c composed of a reinforcing bar of about 3 mmφ and a hoop bar having an outer diameter of about 150 mm and a main bar connecting these hoop bars.
Was built, and this was filled with crushed stone 4b having a size of about 25 mm or less to form a pile diameter of about 200 to 250 mm. The drainage reinforcement pile 4 of the present invention also has a tensile resistance of the ground 1 and a drainage function, like the drainage reinforcement pile of the first invention.

FIG. 4 shows the drainage reinforcement pile 4 of the present invention in a tank 7.
2 shows an example of construction in which the ground 1 is placed in the liquefaction risk area A in an inclined state and a vertical state. Further, the drainage reinforcement pile 4 of the present invention can be applied to a shallow (solid) foundation structure such as a retaining wall in addition to a tank.

FIG. 5 shows a construction example in which the drainage reinforcement pile 4 of the present invention is laid in the vertical state and the inclined state in the liquefaction risk area A of the support ground 1 of the structure 8 having the support pile 7. is there.

As described above, the drainage reinforcement pile of the present invention can be installed diagonally below the existing structure, and the excess pore water generated immediately below the structure is quickly drained to strengthen the ground. Can be achieved.

FIG. 6 shows an example of construction on a river embankment or road embankment 9, in which drainage reinforcement piles 4 are laid in a state substantially orthogonal to the slope, and corrugated pipe 10 is used at the slope exposed portion. The water is collected in the water collecting box 5.

[0020]

【The invention's effect】

1) Arrange a deformed PC rod having an uneven surface in a long hole drilled in sandy ground, and densely fill crushed stones in the gap between the deformed PC rod and the long hole. As a result, the crushed stone meshes with the surrounding sandy ground as well as with the deformed PC rod, so when a tensile force acts on the ground, this tensile force is transmitted to the deformed PC rod through the crushed stone, resulting in an irregular shape. The PC rod resists the tensile force of the ground. Further, the compressive force of the ground is also resisted by the deformed PC rod and the crushed stone, and the ground is strengthened. 2) A cage rebar consisting of several main bars and hoop bars is placed in a long hole drilled in the sandy ground, and crushed stones are densely filled in the gap between the basket rebar and the long hole. As a result, the crushed stone meshes with the surrounding sandy ground and also with the cage rebar.When tensile force acts on the ground, this tensile force is transmitted to the cage rebar through the crushed stone, and as a result, the cage rebar Resists the tensile force of the ground. The compressive force of the ground is also resisted by the cage rebar and crushed stone, and the ground is strengthened.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of construction of a drainage reinforcement pile on an underground buried object or a semi-underground structural structure ground.

FIG. 2 is a structural view showing an embodiment of the drainage reinforcement pile of the first invention.

FIG. 3 is a structural view showing an embodiment of the drainage reinforcement pile of the second invention.

FIG. 4 is a diagram showing an example of construction of the drainage reinforcement pile of the present invention on the tank ground.

FIG. 5 is a diagram showing an example of construction of the drainage reinforcement pile of the present invention on a structure ground having a support pile.

FIG. 6 is a diagram showing an example of construction of the drainage reinforcement pile of the present invention on a road embankment.

[Explanation of symbols]

 1 Sandy ground 2 Buried object 3 Semi-underground structure 4 Drainage reinforcement pile 4a Deformed PC rod 4b Crushed stone 4c Basket rebar 5 Water collecting mass 6 Tank 7 Support pile 8 Structure 9 Road embankment 10 Corrugated pipe

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Masahiro Okamoto 2-3-17-403, Fujigaoka, Midori-ku, Yokohama-shi, Kanagawa 403 (72) Kenzo Ochi 3-22-9- Kirigigaoka, Midori-ku, Yokohama, Kanagawa 108 (72) Inventor Osamu Endo 2-13-12 Miyazaki, Miyazaki-ku, Kawasaki-shi, Kanagawa

Claims (2)

[Claims] 1. A deformed PC rod having an uneven surface is arranged in a long hole drilled in a sandy ground, and crushed stones are densely filled in a gap between the deformed PC rod and the long hole. A drainage reinforcement pile characterized by being constructed. 2. A cage rebar composed of several main bars and hoop bars is arranged in a long hole drilled in sandy ground, and crushed stones are densely filled in a gap between the basket rebar and the long hole. A drainage reinforcement pile characterized by being configured as follows.