JPH05272137A - Constructing method of rotary interpenetrating steel pipe pile - Google Patents

Abstract

PURPOSE:To carry out compaction and simultaneously increase the density of earth inside a pipe for enhancing the blockage at the end part of a pile by pressedly driving bar-shaped rods into the earth inside the pipe at the end part of the pile while giving vibration to them. CONSTITUTION:Steel rods 6 are pressedly driven from above toward the earth 5 inside the pipe at the end part of a pile while giving vibration to them. When the ends of the rods 6 have reached the end part depth of a rotary interpenetrating steel pipe pile 1, driving is completed. At that time, the end of each rod 6 is formed in a conical shape, and a plurality of rods 6 arranged at equal intervals are simultaneously and pressedly driven into the rotary interpenetrating steel pipe pile 1. According to strata, a small hole is penetrated in the center of the rod 6 along the entire length thereof, and it is opened at the end conical part, so that the water in the earth 5 inside the pipe at the end part of the pile can be discharged to enhance the effect of compaction. According to the driving depth of the rod 6, rods are suitably added by using joints 6a and driven. Thus, the application range of the rotary interpenetrating steel pipe pile 1 can be extended, and low-noise, low-vibration, and free-from-removing-earth foundation piling work can be realized, so that cement milk can be dispensed with, and working environment can be properly maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a rotary penetration steel pipe pile. More specifically, the present invention relates to a method of constructing a rotary penetration steel pipe pile that allows a foundation pile to penetrate without noise, vibration, and soil in the suburbs of urban areas.

[0002]

2. Description of the Related Art Steel pipe piles are often used as foundation piles for civil engineering and construction along with prestressed concrete piles and cast-in-place concrete piles. Conventionally, steel pipe piles have been penetrated into the soil by hitting with a hammer, so noise,
Although there is a drawback that the vibration is severe, the present inventors have improved this and developed a drill steel pipe pile for rotary penetration, for example, Japanese Patent Laid-Open Nos. 1-94112, 1-146011, and 1-46011. -127718 publication.

[0003]

The supporting force of a pile is generally considered as the sum of the frictional force on the peripheral surface of the pile and the supporting force at the tip.
The rotary penetration steel pipe pile is provided with a spiral rib having a height of 20 mm or less over a predetermined length on the outer surface and the inner surface of the pile tip portion, and the pipe soil is caused by the action of the spiral rib on the inner surface of the pile tip portion with the rotation penetration. It is compacted to a completely closed state, and although it is an open-end pile, it has the same tip support force as a tip-closed pile of the same diameter, but the pile diameter is 500 ~
Although such a compaction effect is recognized up to 600 mm, when the size is larger than this, the pile and the pipe soil show different behavior, and the compaction effect does not reach the central part,
In addition, if the ground is loosened with a pre-auger or the like to improve the penetrability of the pile, the bearing capacity will be further reduced, and even if the pile diameter is unnecessarily increased, the bearing capacity of the pile will not increase.

Therefore, a method of filling the mortar at the tip of the pile with mortar to make it closed as a means for promoting the blockage of the tip can be considered. New problems arise, such as the need to treat the residual soil as industrial waste for replacement.

[0005]

The present invention is characterized in that after a rotary penetration steel pipe pile is penetrated to the support layer, the rod-shaped body is press-fitted from above the inside of the pile toward the tip end pipe soil while vibrating. To do.

[0006]

[Operation] According to the present invention, a rod-shaped body, for example, a rod having a small diameter is vibrated and press-fitted into the pipe soil inside the pile tip end portion, so that the vibration is transmitted to the pipe soil and compacted at the same time. , The density of the soil in the pipe increases due to the increase in the volume of the rod portion, and the closure of the tip portion is promoted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIGS. Figure 1
Indicates a state in which a rotary penetration steel pipe pile 1 with a diameter of 800 mm is penetrated to a support layer with a depth of 15 m, 2 is an inner spiral rib provided on the inner surface of the tip of the rotary penetration steel pipe pile 1, 3 is also an outer spiral rib, 4 is the surrounding stratum. In this state,
A steel rod 6 having a diameter of 100 mm was press-fitted into the pipe inner soil 5 at the tip of the pile from above while vibrating. The tip of the rod 6 has a conical shape to enhance the penetrability. As a means for vibrating and press-fitting, a vibro hammer or the like usually used for driving a sheet pile is suitable. The tip of the rod 6 was made to reach the depth of the tip of the rotary penetration steel pipe pile 1 to complete the driving. By the way, the state of the formation (N value distribution) in this embodiment is shown in FIG.

According to the experiments conducted by the present inventors, the distance between the rod 6 exerting the compaction effect and the inner surface of the rotary penetration steel pipe pile 1 in the present invention is about 200 to 250 mm. Therefore, in this example, as shown in the cross-sectional view of FIG. 2, three rods were equally press-fitted to the inner surface of the rotary penetration steel pipe pile 1 having a diameter of 800 mm at a position of about 200 mm to the depth of the tip of the pile at the same time. The number of rods should be determined appropriately according to the above criteria according to the pile diameter. In order to press-fit all the rods at the same time, if the vibro hammer has insufficient ability, a small number of rods may be sequentially press-fitted.

Depending on the formation, a pore having a diameter of, for example, about 10 mm is passed through the center of the entire length of the rod to open it in a conical tip portion so that the water content in the pipe soil 5 at the tip of the pile is discharged to obtain a water content. If it is lowered, the compaction effect is promoted, and the pile bearing capacity is more effectively expressed. If the press-fitting depth of the rod exceeds the length of a normal round steel rod, the press-fitting is done by adding this as appropriate, but since only the tip portion of the rod 6 finally contributes to the supporting force. In some cases, the joint 6a may be reseparable, and after press fitting for a predetermined length, only the rod at the tip may be left in the ground and the other may be recovered.

With respect to the rotary penetration steel pipe pile 1 in which the rod 6 of this embodiment was press-fitted and the rotary penetration steel pipe pile 1 in which the rod was not press fit for comparison, the tip supporting force at the time of sinking 80 mm was measured by a strain gauge. However, the former is 375 tons and the latter is
It was 197 tons, and by vibrating and press-fitting the rod, it was possible to develop about twice the tip supporting force.

[0011]

EFFECTS OF THE INVENTION According to the present invention, even if the diameter is 600 mm or more, a sufficient supporting force can be exerted on the rotary penetration steel pipe pile, and as a result, the range of application of the rotary penetration steel pipe pile is expanded. Even for works that could not be applied, it has the excellent effect of realizing low noise, low vibration, and soil-free foundation pile work, and since it does not use cement milk etc. on site, it deteriorates the work environment. Nor.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a state diagram of a formation in the embodiment of the present invention.

[Explanation of symbols]

 1 Rotating Penetration Steel Pipe Pile 2 Inner Spiral Rib 3 Outer Spiral Rib 4 Peripheral Formation 5 Pile Tip Pipe Inner Soil 6 Rod

Claims (2)

[Claims] 1. A method of constructing a rotary penetration steel pipe pile, characterized in that after a rotary penetration steel pipe pile is penetrated to a support layer, the rod-shaped body is press-fitted from above the pile toward the soil inside the tip pipe while vibrating. . 2. The method for constructing a rotary penetration steel pipe pile according to claim 1, wherein the rod-shaped body has pores passing through the center along its entire length and opened at the tip of the rod-shaped body.