JPS6044449B2 - Compaction method for sandy ground and its construction equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sand ground compaction method and a construction machine therefor.

The conventional compaction method for sandy ground involves repeatedly penetrating the sandy ground using a rod equipped with a screw over its entire length, and then repeatedly pulling the rod up to the ground surface and then penetrating it again. That is, this is shown in a graph as shown in FIG. In other words, the passage of time is shown from left to right in the diagram. death,
As is clear from the broken line a in this graph, where the vertical axis shows the penetration depth of the rod, efficiency is poor because the rod is pulled up to the ground surface 6 at each step, and the compaction effect during re-penetration is not transmitted to the bottom end. Since it is difficult, the compaction effect is poor, and there are also drawbacks such as poor replenishment of sand from the surrounding ground. In view of the above problems, the present invention proposes a construction method for efficiently compacting sandy ground by operating a rod dotted with short screw blades using a rotating mechanism and a high-frequency vibrator, as well as a construction machine for implementing this construction method. It is something to do.

In addition, in this type of compaction method, the frequency of the vibrator normally used is 500 to 600 vibrations per minute, and a vibrator that can obtain vibrations of 1000 times or more per minute is called a high-frequency vibrator. First, the construction machine for carrying out the construction method of the present invention will be explained based on Fig. 1. 1 is a rod, and short screw blades 2 of about one circumference are fixed at regular intervals on the outer circumference of the rod. There is.

At the upper end of this rod 1, there is a high frequency vibrator 3, a motor,
A rotating mechanism 4 consisting of a speed reducer and the like is attached. Next, an embodiment of the construction method of the present invention using the construction machine as described above will be described with reference to FIGS. 2 and 3.

First, the construction machine A of the present invention, which is set up on the ground, is rotated in the forward direction while penetrating into the ground using the screw blades 2.

In this case of penetration, if the rod 1 penetrates smoothly only with the screw blades 2, there is no need to operate the high-frequency vibrator 3, but if the penetration speed becomes slow when the rod 1 penetrates only with the screw blades 2, the high-frequency vibration The vibrator 3 is operated to use both high frequency vibration and the screw blade 2.

When the rod 1 reaches a predetermined depth in this way, the rod 1 is reversed, and the rod 1 is pulled out for a predetermined length by the action of the screw blades 2 as shown in Figure 2, and then the rotation of the rod 1 is stopped and the high-frequency vibrator When re-penetrating the hole shown in Fig. 3 by operating only the rod 3 and vibrating the rod 2 at high frequency, the rod descends by a length shorter than the pulling length and compacts the sand.

By repeating the above operations, the sand around the rod 1 flows into the outside of the rod 1 formed by the hole after the rod 1 is pulled out and the screw blades 2, and the sand pile 7 is compacted.

Therefore, when the entire rod 1 is exposed on the ground surface 6, a firmly compacted sand pile has been created in the sandy ground 5.
The construction method of the present invention is shown in the graph of FIG. This graph also shows the passage of time from left to right, with depth plotted on the vertical axis. As can be seen from the broken line a in this graph, the rod that has reached a predetermined depth A is pulled out to the depth A, then penetrated to the depth C, then pulled out to the depth 2 and penetrated to the depth E. By repeating this operation, the rod reaches the ground surface. Therefore, efficiency is improved compared to the conventional construction method in which the rod is pulled out to the ground surface in each step. In addition, since the screw blades 2 on the outer periphery of the rod 1 are short and scattered, the inflow of sand to the outer periphery of the rod 1 is good, and sand is formed from the outer periphery of the rod 1 to the lower end of the rod 1 when it is pulled out. The sand flows into the hole, and the sand around the hole also flows into the hole, so the sand supply is good, and when re-penetrating, the sand is sufficiently compacted by the driven rod 1, so it is strong. This has the effect of forming sand piles.

When the energies of vibrations are equal, the amplitude is large at low frequencies and small at high frequencies. Moreover, since vibrations attenuate faster in the ground, high frequencies cause much smaller vibrations felt by the human body at a certain distance from the vibration source. Therefore, in the construction method of the present invention, the re-penetration of the rod 1 is performed by the high-frequency vibrator 3, so there is less vibration propagation to the surrounding ground, and there is less risk of pollution caused by vibration than in the conventional construction method. Furthermore, the construction machine that implements the construction method of this invention has an extremely simple mechanism, consisting of a plurality of short screw blades dotted at appropriate intervals around the outer circumference of the rod, and a high-frequency vibrator and rotation mechanism installed at the upper end of the rod. Therefore, it has advantages such as easy handling.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view of the construction machine that implements the construction method of the present invention, Figs. 2 and 3 are partially longitudinal front views of the construction state, Fig. 4 is a graph showing the conventional method, and Fig. 5 is a graph showing the construction method of the present invention. 1...Rod, 2...Screw blade, 3...High frequency vibrator, 4...Rotating mechanism,
5...Sandy ground.

Claims (1)

[Claims] 1. Using a construction machine with short screw blades dotted at appropriate intervals around the outer periphery of a rod that has a high-frequency vibrator and a rotation mechanism at its upper end, the rod is rotated in the forward direction until it reaches a predetermined depth. During the penetration process, the high-frequency vibrator may or may not be used, and after the rod has penetrated to a predetermined depth, the rod is rotated in the opposite direction and pulled out to a predetermined length, and then the rotation of the rod is stopped and the rod is vibrated by the high-frequency vibrator. The sand ground is characterized by performing a re-driving operation of a length shorter than the pulling length using a chisel, and thereafter repeating the above-mentioned pulling and re-driving operations to reach the ground and compact the sand in the surrounding ground. Compaction method. 2 Construction in which multiple short screw blades are scattered at appropriate intervals around the outer periphery of a rod that has a high-frequency vibrator and a rotating mechanism that can freely rotate in forward and reverse directions at the upper end, and a portion of only the rod is provided between each screw blade. Machine.