JPH0443122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pile embedding method in which foot protection concrete is poured into an excavated hole and piles are inserted into the concrete.

[Prior art and problems to be solved by the invention]

Currently, various pre-boring methods have been developed and implemented as low-pollution construction methods, in which cement milk is injected into the borehole and ready-made piles are erected. However, only a relatively small supporting capacity is recognized. The applicant has proposed a pre-boring method in which ready-mixed concrete is used for the expanded portion at the tip (see Japanese Patent Laid-Open No. 56-6822).

By the way, when an auger is used as an excavator and a hole is drilled by the muddy water method, slime often forms at the bottom of the hole.

This invention was developed in order to treat the slime, cast foot protection concrete at the bottom, and insert ready-made piles into the concrete, thereby achieving a tip bearing capacity coefficient comparable to that of the impact method.

[Means for solving problems]

This invention uses the muddy water method to drill a hole in the ground with an excavator, and then the slime that collects at the bottom of the hole is softened by injecting and stirring a slime treatment agent made of water glass or cement milk, and then the slime is softened. Cement milk is press-fitted into the bottom of the hole, the softened slime is placed on the drilling head, and the excavator is pulled up. Concrete is poured into the hole, and a ready-made mold is placed so that the tip is fixed in the concrete. This is a method of erecting piles.

〔Example〕

The construction outline of this construction method is as shown in Figs. 1 to 6, which show an example in which the tip portion is enlarged.
First, using the muddy water method, a hole A is drilled in the ground with an excavator 1 (see Figure 1), and then an enlarged hole B is excavated with an enlarged head 2 (see Figure 2).
Next, the slime S at the bottom of the enlarged hole B is treated (see Figure 3), and then cement milk is poured into the underside of the softened slime, and then concrete 3 is poured through the rod of the excavator 1 (see Figure 3). (see figure 4),
Next, the excavator 1 is pulled up (see FIG. 5), and the ready-made pile C is then inserted into the concrete 3.

Details of slime processing are shown in FIGS. 7-9. When using water glass as a slime treatment agent, the main agent is industrial water glass JIS-3 standard product, and the curing agent is a solution of alkali or acid such as baking soda, phosphoric acid, dilute sulfuric acid, or cement, gypsum, calcium carbonate, etc. Use a suspension of The amounts of water glass and hardening agent and the softening strength of the slime are changed depending on the shape of the drilling bit, the slime particle size distribution, the water content ratio, etc. When using cement milk as a slime treatment agent, use cement, lime, or a commercially available cement-based soft soil conditioner. During construction, the water glass or cement milk is poured into the slime from the tip of the bit, and after stirring with the slime, the rotation of the rod is stopped to soften and harden the slime. Next, cement milk is forced under the soft hardened slime S', and the rod, that is, the excavator 1 is pulled up with the hardened slime placed on the excavation head. The pulling speed is set to match the amount of cement milk injected. Next, the cement milk used in the slime treatment is changed to ready-mixed concrete, and the amount is set to a predetermined height, that is, the amount that can be filled into the enlarged hole B. If necessary, the enlarged head 2 is reduced while injecting the pile circumference fixing liquid over it, and the excavation is started. The machine 1 is pulled up, and then the ready-made pile C is inserted.

The enlarged holes B can be provided at several locations not only at the bottom but also at the middle by operating the enlarged head and filled with concrete to form bulbs or knots. Also, as a slime treatment agent, high-grade water-based synthetic resins made from polymers of starch and polyacrylic acid, such as Sanyo Kasei Kogyo's "Sunwet", are used.
etc., or the above-mentioned ones may also be used.

〔Effect of the invention〕

This invention has the above-mentioned structure, and the slime at the bottom of the enlarged hole is softened, cement milk is injected into the bottom of the slime, and the slime is removed by placing it on the drilling head. Even slime removal can be done reliably. Next, concrete is filled and ready-made piles are inserted into the concrete, so the cast-in-place piles provide sufficient bearing capacity, and higher bearing capacity can be expected than in the conventional cement milk method.

[Brief explanation of drawings]

Figures 1, 2, 3, 4, 5 and 6 are cross-sectional views of the construction process of this invention;
8 and 9 are explanatory diagrams of slime processing. A...Drilling, B...Enlarged hole, C...Ready-made pile, 1
...excavator, 2...expansion head, 3...concrete.

Claims (1)

[Claims] 1 Using the muddy method, a hole is drilled in the ground with an excavator, then a slime treatment agent made of water glass or cement milk is injected into the slime that collects at the bottom of the hole and stirred to soften it, and then the slime is poured under the softened slime. Cement milk is pressed into the side, and the excavator is pulled up with the softened slime placed on the excavation head. Next, concrete is poured into the hole, and ready-made piles are placed so that the tips are fixed in the concrete. A method of embedding piles.