JPS6117972B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for driving piles into a rubble layer.

(Prior Art) When driving piles into normal ground, the piles are driven using a driving machine such as a diesel hammer or a vibro hammer.

However, if the ground is a rubble layer containing large rocks, it is impossible to drive piles using the above-mentioned driving machine as is.

Conventionally, when driving piles into such a rubble layer, large rocks are removed using a grab bucket (large rocks that cannot be removed even with a grab bucket are removed by other suitable means). The piles were then moved to another location), and then the piles were driven using the above-mentioned driving machine.

Alternatively, if it was impossible or extremely difficult to remove large rocks, consideration had to be given to driving piles elsewhere in the design.

(Problem to be solved by the invention) However, a great deal of effort is required to remove large rocks, especially when a large number of piles need to be driven. Become something.

Further, if the design allows driving the piles in other locations, there is no problem, but such a design change is not always allowed.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to make it possible to use ordinary driving machines such as diesel hammers and vibro hammers without excluding large rocks.
The object of the present invention is to provide a method for driving piles into a rubble layer.

(Means for Solving the Problems) The present invention provides a rotatable cylindrical casing having a ground excavation blade formed at its tip, and a rotatable cylindrical casing fitted in the casing. A vertical hole is provided in the rubble layer using an auger screw, then replacement sand is poured into the vertical hole to form a sand pile in the rubble layer, and then the pile is driven into the sand pile.

(Function) By using the casing as described above and the auger screw fitted therein, it is possible to easily dig a vertical hole even in a rubble layer containing large rocks.

Then, if replacement sand is poured into this vertical hole to form a sand pile in the rubble layer, and a pile is driven into this sand pile, the penetration resistance of the pile is much smaller than that of large rocks. Therefore, piles can be easily driven using a normal driving machine such as a diesel hammer or a vibro hammer.

In other words, the present invention uses sand piles, which are normally used to drain water from the soil and promote soil consolidation, as a means to facilitate pile driving.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

First, as a device for excavating a vertical hole in the rubble layer, several Tungaloy Bits 3 were attached to the tip of the head 2 of the auger screw 1 as shown in Fig. 1, and the outer and inner circumferential surfaces were both smooth and rotating. A blade part 5 for ground excavation made of special steel is formed at the tip of a possible casing 4, and a structure suitable for rock excavation is used. These auger screw 1 and casing 4 are the head 2 of the auger screw 1.
is set so that the tip of the casing 4 is approximately 70 cm ahead of the tip of the casing 4.

First, the auger screw 1 and the casing 4 are set at a desired location on the rubble layer, and the auger screw 1 and the casing 4 are rotated in opposite directions, and the auger screw 1 is rotated in the vertical direction as shown in Fig. 2A. As the hole is drilled, the casing 4 is sunk. At this time, as mentioned above, the auger head 2
Since the Tungaloy Bit 3 is attached to the tip of the donut auger and the blade part 5 made of special steel is attached to the tip of the casing 4, it is possible to extract a large torque from the donut auger, and since both rotate in the opposite direction, Excavation efficiency can be improved, and test results show that vertical holes can be easily drilled in the rubble layer. When the drilling is completed from the rubble layer to the lower support layer (not shown) as shown in Figure B, the auger screw 1 and casing 4
The rotation of the auger screw 1 is stopped, and while only the auger screw 1 is rotated, leaving the casing 4, it is lifted upward as shown in FIG. Next, replacement sand 6 is poured into the hollow casing 4, that is, into the vertical hole, as shown in FIG. After charging, the casing 4 is pulled out as shown in FIGS. E and F, and the replacement sand 6 is formed in the shape of a pile in the rubble layer.

A sand pile formed by such replacement sand 6 is
It is usually used to drain water from the soil and promote soil consolidation.

However, in addition to being able to drain water and promote consolidation, sand piles also have low penetration resistance when driving various types of piles such as steel pipe piles, steel sheet piles, and H-type piles. have a property.

Therefore, if we focus on this property of low penetration resistance and drive the various types of piles described above into sand piles, it is possible to easily penetrate the rubble layer with commonly used pile drivers such as diesel hammers and vibro hammers. Piles can be driven in.

Further, such sand piles can be formed continuously and efficiently in the following manner.

That is, after forming a pile-like body of replacement sand 6 at the position shown in FIG.
The steps described above are performed in sequence to form a pile-shaped body using the replacement sand 6. Next, the above-mentioned steps are sequentially performed at a position between the pile-like bodies at these positions to form a pile-like body using the replacement sand 6. By sequentially forming pile-like bodies using the replacement sand 6 in this way, parts of the pile-like bodies are polymerized, and a continuous wall 7 made of the replacement sand 6 is constructed as shown in FIGS. 6A and B. I can do it.
The continuous wall 7 constructed by polymerizing a part of the pile-shaped body made of such replacement sand 6 is suitable for continuously driving steel sheet piles and steel pipe sheet piles in order to stop water.

Next, regarding providing a vertical hole in the rubble layer and forming sand piles in the rubble layer, another example different from the above example is shown in Figs. 3A to G, Figs. 5 and 7. I will explain based on this.

In this case, the steps from FIGS. 3A to D, that is, from the drilling of the auger screw 1 until the replacement sand 6 is introduced into the cavity in the casing 4, are the same as those of the previous embodiment, that is, FIGS. 2A to D. The process is similar to that shown. In this embodiment, after the replacement sand 6 is put into the casing 4 at the position shown in FIG. Then, excavate the hole using auger screw 1. After the excavation is completed, as shown in Figure F, only the auger screw 1 is pulled up with the casing 4 remaining, and after discharging the gravel together with it onto the ground surface G, replacement sand 6 is thrown into the cavity of the casing 4. . After charging, the casing 4 at the previous position is pulled out to form a pile-shaped body.
Hereinafter, in the same way, the position as shown in H in the same figure,
Furthermore, by sequentially applying the replacement sand 6 to adjacent positions, it is possible to construct a wall 7a of the replacement sand 6 in a substantially continuous state as shown in FIGS. 7A and 7B.
Such a continuous wall 7a is suitable for driving H-shaped piles during earth retaining. In this way, when the replacement sand 6 is formed into a pile shape at an adjacent position, the casing 4 at the position
The replacement sand 6 is introduced into the casing 4 at the position , and then pulled out.
This is because if the excavation work is performed, the displacement sand 6 at the position may have an adverse effect on the pile-shaped body.

When constructing the continuous walls 7, 7a using the replacement sand 6 as described above, if the pile-like bodies made of the replacement sand 6 polymerize, the operations of excavation, pulling up the auger screw, introducing the replacement sand, and pulling out the casing are sequentially repeated. If the pile-shaped bodies made of replacement sand 6 are adjacent to each other, a part of the above-mentioned work may be repeated in parallel.

(Effects of the Invention) As described above, the present invention effectively utilizes the property of sand piles that has low penetration resistance, which has not received attention in the past. It also becomes possible to easily drive piles without removing large rocks using a normal driving machine such as a diesel hammer or a vibro hammer.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing an example of an auger screw and a casing using the method according to the present invention, and FIGS. 2A to 2F are schematic sectional views showing the order of implementation of the embodiment of the method according to the present invention. 3A to 3H are schematic sectional views showing the order in which the method according to the present invention is carried out in succession; FIG. 4 is a plan view for explaining the order in which a continuous wall is constructed by the method shown in FIG. 5 is a plan view for explaining the order of constructing a continuous wall by the method shown in FIG. 3; FIGS. 6A and B are sectional views and perspective views of the continuous wall completed by the method shown in FIGS. 2 and 4;
7A and 7B are a sectional view and a perspective view of a continuous wall completed by the method of FIGS. 3 and 5. FIG. 1...Auger screw, 4...Casing, 5...Blade part, 6...Displacement sand.

Claims (1)

[Claims] 1. A vertical hole is excavated in the rubble layer using a rotatable cylindrical casing with a ground excavation blade formed at the tip and an auger screw fitted into the casing, and then only the auger screw is used. The sand is removed, and replacement sand is poured into the area to form a sand pile.
A method for driving piles into a rubble layer, the method comprising: thereafter, removing the casing and driving the pile into the sand pile.