JPH0444044B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The present invention is characterized in that when the pile is driven into a cement layer, the rewetting lubricant layer provided on the pile surface absorbs water and creates a beveled surface between the cement layer and the pile surface. This invention relates to a pull-out and retrieval type pile that allows the pile to be easily pulled out.

Conventional technology: When constructing column-row earth retaining walls by injecting cement milk into ground holes drilled with an earth auger, H-shaped steel piles are driven into key points of the holes filled with cement milk for reinforcement. However, when a basement, etc. for a building is constructed within the column-row earth retaining wall, the column-row earth retaining wall becomes obsolete. In this case, in order to recover relatively expensive H-beam steel, there is a conventional method of applying grease or the like to the pile surface in advance to create a bevel surface and then pulling the pile out. However, it is still difficult to pull out the pile, and special It had the disadvantage of requiring a powerful pile extraction device.

Problems to be Solved by the Invention The present invention provides that when retrieving piles driven into a cement layer, a good lubricated surface is formed, and a beveled surface is completely formed when the pile is pounded. To provide a pull-out and retrieval type pile that can be easily pulled out.

Means for Solving the Problems The present invention provides a rewettable lubricant layer on the pile surface, which is made by kneading a water-absorbing polymer and a rewettable binder and solidifies it by drying. A pull-out and retrieval type pile was constructed by connecting the The water-absorbing polymer is a highly water-absorbing polymer that is insoluble in water and absorbs hundreds of times its own weight in water and swells to form a hydrogel. Examples include acrylic acid copolymers (cross-linked polyacrylic acid, starch polyacrylic acid copolymers, etc.),
The rewetting binder is made of acrylic acid vinyl alcohol copolymer, crosslinked polyethylene oxide, crosslinked carboxylmethylated cellulose sodium salt or calcium salt, etc.The rewetting binder solidifies by drying, but becomes pasty or muddy when water is absorbed. , agar-like substances, such as starch paste, polyvinyl alcohol paste, etc. Also, the deformable block mentioned above is a material that dents or shatters when pushed.
For example, hard Styrofoam, rubber, cork, cans, etc.

Function As shown in FIG. 5, when the pile 1 is put into the cement layer 11 in a cement milk state, the water-absorbing polymer 6 and the rewetting binder 5 are absorbed into the cement layer 11.
absorbing water, the water-absorbing polymer 6 swells into large and small spheres, the rewetting binder 5 becomes paste-like, increasing the overall thickness of the rewetting lubricant layer 2, and the cement layer 11 is removed from the pile surface. solidify. In this case, the spherical water-absorbing polymer 6 becomes a rolling ball, and the pasty rewetting binder 5 takes the place of lubricating oil to form a lubricating surface between the cement layer 11 and the pile surface. In this way, when the head of the pile 1 is strongly hit, the lower end of the pile is pushed into the deformable block 8 and the pile 1 moves slightly downward, as shown in Figure 6, and the gap between the cement layer 11 and the pile surface is completely closed. The edges are cut to create an extremely smooth lubricated surface. Therefore, the pile can be easily pulled out by grasping the pile head with a wire and pulling it up with a crane.

Embodiment FIGS. 1 to 3 are explanatory diagrams of one embodiment.
1 is an I-type steel pile with a total length of approximately 5 m, a cross section with a flange length of 15 cm, a web length of 30 cm, a thickness of 0.7 cm, and a weight of approximately 165 kg. 2 is a rewetting lubricating layer fixed to the pile surface of the flange 3 and web 4, and the rewetting binder 5 is 100 parts of starch glue, and the water absorbing polymer 6 is acrylic acid vinyl alcohol copolymer (trade name Sumikagel SP-510 (Sumitomo)). chemical)
30 parts of this was mixed with an appropriate amount of water and kneaded until it became a paste, and this paste was applied to the pile surface and dried and solidified to form a 100μ thick layer. 7 is a protective layer made of kraft paper that is adhered to the rewetting lubricant layer 2 while it still has adhesive strength. 8 is a hard Styrofoam block formed into an I-shaped material larger than the pile 1, and an I-shaped groove 9 is recessed in the upper surface of the block.
With the lower end of the pile inserted into the mold groove 9, the block 8
is connected to pile 1.

As shown in Fig. 4, the above piles 1 are continuous row holes 1 for a column retaining wall formed by an earth auger.
0 cement milk. As described above with reference to FIG. 5, the rewetting lubricant layer 2 forms a lubricating surface on the pile surface by absorbing the moisture in the cement layer 11 made of low alkaline cement milk, and the cement layer 1
10 days after Pile 1 has solidified, the head of Pile 1 is struck with a Monken equipped with an earth auger to lower the pile slightly and push the lower end of the pile into the I-shaped groove 9 of the block by a depth l, thereby removing the cement layer 11. The edge cut surface between the pile and the pile surface was completely cut and the pile was pulled out. When the weather continues to be sunny and the water in the rewetting lubricant layer 2 is removed and the swollen lubricant layer shrinks into a skeleton shape, leaving a gap between the cement layer 11 and the pile surface, the pile cap is hammered in the same way to complete the edge cut surface. When I pulled up the pile, it was easily pulled out. In these cases, the piles could be pulled up using a normal crane by adding a somewhat large traction force to the weight of the piles.

Note that the rewetting lubricant layer may be prepared in advance as an adhesive tape and adhered to the pile surface during use.

Effects of the Invention The present invention is as described above, in which water is absorbed from the unsolidified cement layer, the water-absorbing polymer of the rewetting lubricant layer swells into a spherical shape and becomes a trochanter, and the rewetting binder becomes pasty and muddy. The deformable block acts as a lubricating oil and forms a spherical lubricating surface between the solidified cement layer and the pile surface, and since the deformable block is located at the bottom end of the pile, the pile can be moved slightly downward by the hammering. So,
The lubricating surface can be made into a completely edged surface,
Therefore, the pile can be easily pulled out from the cement layer.

[Brief explanation of the drawing]

Fig. 1 is a front view of an embodiment of the present invention, Fig. 2 is an exploded perspective view of the main parts of the above, Fig. 3 is an enlarged sectional view of the rewetting lubricant layer of the above, and Fig. 4 is the state of use of the same. FIG. 5 is an enlarged sectional view of the same layer showing the action of the rewetting lubricant layer, and FIG. 6 is a front sectional view showing the action of the pile lower end block. In the figure, 1...Pile, 2...Rewetting lubricant layer, 5...
Rewetting binder, 6... Water absorbing polymer, 8...
Block, 9...I-shaped groove, 11...cement layer.

Claims (1)

[Claims] 1. A pull-out and retrievable pile that has a rewetting lubricant layer on the pile surface made by kneading a water-absorbing polymer and a rewetting binder and solidifying it by drying, and a block that can be deformed by hammering is connected to the lower end of the pile.