JPH09111757A - Pile construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute a ground improvement work at a great depth at low cost with high efficiency based on a dry construction method. SOLUTION: A tube-like casing 9 is pressed into the underground area where a powder-made ground improvement material 11 is charged thereinto. After the powder is charged, the casing 9 is pulled out and the ground improvement material in the casing 9 is left over underground in the form of a post. Then, an agitation rod with an agitation blade whose agitation blade side D is larger than the post size (d) is advanced into the post-like ground improvement material 11 from above while the agitation blade is being turned, thereby mixing and agitating the improvement material 11 together with the earth and sand in the surrounding area. Then, the agitation rod 10, while it is being turned inversely, is pulled out, thereby forming a post of a pile 12 mixed with the improvement material 11 and the earth and sand in the surrounding peripheral area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pile construction method for stably strengthening soft ground by using a dry ground improvement material.

[0002]

2. Description of the Related Art As a ground improvement method for scientifically stabilizing a soft ground, there is a method of mixing and agitating a ground improvement material on a soft ground, and it is widely used in various civil engineering and construction works. Generally, the construction method is roughly divided into a dry improvement method and a wet improvement method depending on the form of the ground improvement material mixed and stirred with soil. Among them, the dry improvement method is a method in which a ground improvement material is used as a powder or a granule as it is, and is mainly used for improving a ground having a small depth such as a surface plate due to the properties of the powder or the granule. On the other hand, the wet improvement method is a method in which a soil improvement material is dissolved in a liquid and used, and the ground improvement in which the soil improvement material is solidified into a column in the ground by injecting milk is performed by this method.

[0003]

However, in the wet improvement method used for improving deep ground, various facilities such as a plant, a generator, a water tank, and a water supply are not installed for the milk injection work. However, there is a problem in that not only a large site space is required, but also transportation costs, maintenance costs, and an increase in the number of workers increase, construction costs increase, and construction efficiency is poor.

It is an object of the present invention to provide a pile construction method capable of efficiently improving a deep soil by a dry construction method at a low construction cost at a low cost.

[0005]

A method of constructing a pile according to the present invention comprises a step of press-fitting a tubular casing into the ground,
In the process of introducing the powder or granular ground improvement material into the press-fitted casing, the process of pulling out the casing and leaving the ground improvement material in the casing in a pillar shape in the ground, and the pillar-shaped ground improvement material By rotating the stirring rod with a stirring blade having a larger stirring blade diameter than its column diameter and advancing it from above while mixing and stirring the improved material with the surrounding earth and sand, and by pulling it out while reversing the stirring rod. And a step of forming a pile in which the improved material and the surrounding sediment are mixed. According to this configuration, the powder or granular ground improvement material is charged through the casing press-fitted into the ground, and the mixture is made to enter while rotating the stirring rod. It is possible to form pillars efficiently in the ground. In the construction method, an opening / closing lid is provided at the tip of the casing,
You may make it press-fit to the ground in the closed state of this opening / closing lid, and pull out the said casing in an open state. By providing the opening / closing lid in this way, the earth and sand do not enter the casing during press-fitting into the ground, and the improvement material is not pulled up together with the casing during extraction. In the construction method, a traveling pile driver may be used to press-fit the casing and drive the stirring rod. By adopting the traveling type as described above, when a large number of piles are provided, the means for press-fitting and stirring can be easily moved to the position of each pile.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a side view of the pile driver 1 used in the pile construction method of the present invention. This pile driver 1
Is a machine in which a press-fitting machine 3 and an auger driving machine 4 (FIG. 1) are mounted on a traveling machine body 2, and a leader 7 attached to the traveling machine body 2 via a raising / lowering boom 5 and a leader slide 6.
The press-fitting machine 3 and the auger driving machine 4 are provided side by side near the upper end of the. An outrigger 8 is provided at the rear of the traveling machine body 2. A tubular casing 9 is detachably set on the press-fitting machine 3, a hopper 9a and a vibrator 9b (FIG. 1) for introducing the improvement material are provided on the upper portion of the casing 9, and the lower end of the casing 9 is opened and closed. Lid 9
c (FIG. 1) is provided. The auger driving machine 4 has an auger 1 in which a stirring blade 10b is provided on the outer circumference of a rotating rod 10a.
0 is detachably set as a stirring rod. The stirring blade diameter D of the auger 10 is larger than the outer diameter d of the casing 9.

A procedure of a pile construction method using the pile driver 1 is shown in FIG. First, the casing 9 set in the press-fitting machine 3
Align the lower end of the to the pile core position of the ground G. next,
The leader slide 6 and the outrigger 8 of the traveling machine body 2 are used together to stabilize the casing 9 in a vertical posture.
In this state, the press-fitting machine 3 is driven to press-fit the casing 9 into the ground (FIG. 1 (A)). At this time, the open / close lid 9c at the lower end of the casing 9 is closed. Therefore, it is possible to prevent the sand and sand from entering the casing 9 due to the press-fitting into the ground. The opening / closing lid 9c is preferably attached to the casing 9 so as to be openable / closable so that the opening / closing lid 9c opens to the outside of the casing 9 but does not open to the inside. As a result, the opening / closing cell 9c is removed when the casing 9 is inserted or removed.
Is opened and closed. When the lower end of the casing 9 reaches a predetermined depth, a prescribed amount of powder ground improvement material 11 is put into the casing 9 from the hopper 9a (FIG. 1 (B)). After the completion of the ground improvement material 11, the press-fitting machine 3 is reversely driven to pull out the casing 9 from the ground (FIG. 1 (C)). At this time, the vibrator 9b is driven according to the pulling operation. By this pulling out, the opening / closing lid 9 at the lower end of the casing 9
c is opened, and the ground improvement material 11 in the casing 9 is replaced by the columnar space portion formed in the ground by press-fitting the casing 9 (FIG. 1D). This replacement operation is performed smoothly and reliably by the pushing action due to the pressure difference between the columnar space portion formed in the ground and the inside of the casing 9, the vibration of the casing 9 by the vibrator 9b, and the own weight of the ground improvement material 11. Be seen. Next, the auger 10 with the stirring blade 10b set in the auger drive unit 4 is aligned with the pile core position on the ground G, that is, the center position of the columnar ground improvement material 11, and the auger drive unit 4 is driven. Auger 10
While rotating in the forward and reverse directions, it enters the ground from above (Fig. 1 (E)). Since the stirring blade diameter D of the auger 10 is larger than the column diameter d of the columnar ground improvement material 11, as the auger 10 rotates into the ground, The sand and sand are homogeneously mixed and stirred. Auger 1
When the lower end of 0 reaches the lower end of the columnar ground improvement material 11, the auger 10 is reversely rotated and pulled out from the ground to end the stirring operation (FIG. 1 (F)). This allows
It is possible to form a pile 12 having a pile diameter D, which is a mixture of earth and sand and the ground improvement material 11, in the ground.

According to this pile construction method, the powder ground improvement material 11 and the earth and sand are homogeneously mixed and stirred by the auger 10 without preparing equipment such as a plant, a generator, a water tank, and a water supply, and its stirring blades. Since the piles 12 having the same diameter as the diameter D are formed in the ground, the deep ground can be efficiently improved by the dry construction method at a low construction cost with a sufficient construction space and the number of workers can be reduced. In particular, it is possible to create a wide range of strength improvement areas in the ground, and it can be done in a short period of time. In addition, this method can reduce the water content in the soil and stabilize the soil quality, and thus is particularly effective for improving the ground of highly hydrous soil. Furthermore, since there is almost no generation of vibration, noise, sludge, sewage, and residual soil, not only processing costs are unnecessary, but also the site and surrounding environment can be kept good and site management is easy. In addition, the improved ground constructed in this way has excellent non-settling, water-stopping, and earthquake resistance.

Further, since the traveling pile driving machine 1 is used in the pile construction method, the press-fitting machine 3 and the auger driving machine 4 can be easily carried into the site, and installation work thereof can be omitted. Further, when a large number of piles 12 are provided, the press-fitting machine 3 and the auger drive machine 4 can be easily moved to the formation positions of the piles 12. In the pile driving machine 1 used for the pile construction method, the press-fitting machine 3 and the auger driving machine 4 are provided near the upper end of the leader 7.
The press-fitting machine 3 and the auger driving machine 4 may be exchanged with and removed from the reader 7.

[0010]

The pile construction method of the present invention comprises the steps of press-fitting a tubular casing into the ground, charging a ground improvement material of powder or granules into the press-fitted casing, and The process of pulling out and leaving the ground improvement material in this casing in the shape of a pillar in the ground, and letting this pillar-shaped ground improvement material enter from above while rotating a stirring rod with a stirring blade with a stirring blade diameter larger than the column diameter By including the process of mixing and stirring the improvement material with the surrounding earth and sand, and the process of forming a pile of the improved material and the surrounding earth and sand mixed pile by pulling out while reversing the stirring rod, the depth of The deep ground can be improved efficiently by the dry method at a low construction cost. In the construction method, when an opening / closing lid is provided at the tip of the casing, earth and sand do not enter the casing during press-fitting into the ground, and it is possible to prevent the improving material from being pulled up together with the casing during extraction. . Further, in the above-mentioned construction method, when a traveling type pile driver is used to press fit the casing and drive the stirring rod, it becomes easy to carry the press fit machine and the auger drive machine to the site, and the installation work thereof is also performed. It can be omitted. Further, when a large number of piles are provided on site, the press-fitting machine or the like can be easily moved to the position of each pile.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a procedure of a pile construction method according to an embodiment of the present invention.

FIG. 2 is a side view of a pile driver used in the pile construction method.

[Explanation of symbols]

1 ... Pile driver, 3 ... Press-in machine, 4 ... Auger drive machine, 9 ... Casing, 9c ... Open / close lid, 10 ... Auger (stirring rod),
10b ... stirring blade, 11 ... ground improvement material, 12 ... pile

Claims (3)

[Claims] 1. A process of press-fitting a tubular casing into the ground, a process of charging a powder or granular ground improvement material into the press-fitted casing, and a process of pulling out the casing to improve the ground in the casing. The process of leaving the material in the shape of a pillar in the ground, and by advancing from the top while rotating the stirring rod with a stirring blade with a stirring blade with a larger stirring blade diameter than the column diameter, the improvement material in the surrounding A pile construction method comprising a step of mixing and stirring with soil and a step of forming a pile in which the improving material and the surrounding sediment are mixed by pulling out while rotating the stirring rod in reverse. 2. An opening / closing lid is provided at the tip of the casing,
The casing is pressed into the ground when the opening / closing lid is closed, and the casing is pulled out when the lid is open.
The pile construction method described. 3. The pile construction method according to claim 1, wherein a traveling type pile driver is used to press-fit the casing and drive the stirring rod.