JPH0410928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to compaction pile construction methods, such as sand compaction pile construction methods and cast-in-place concrete pile construction methods.

[Problems to be solved by the prior art and the invention]

The conventional sand compaction pile construction method generally creates a sand pile by putting sand into an outer pipe, and while pulling up the outer pipe, the sand is forced into the ground and compacted. By the way, if there is no need to expect the sandpile to have a dewatering effect, it is possible that if cement or quartz is mixed with the sand, the sandpile will harden by reacting with groundwater in the ground, but if the sandpile does not penetrate sufficiently. The entire body does not harden,
Only the surface layer is cured, and it takes a considerable period of time to cure, making it impossible to achieve uniform strength. In addition, it is difficult to consolidate the ground with mortar that is a mixture of sand, cement, and water, and it is often more appropriate to construct cast-in-place concrete piles.

In view of the above-mentioned circumstances, this invention was developed in such a way that, when injecting and compacting aggregates such as sand, the aggregates are in a dry or nearly dry state, and the aggregates are mixed with the aggregates after being press-injected into the ground and compacted. This is a construction method in which cement immediately undergoes a hydration reaction, and the method described in Japanese Patent Publication No. 63-53924, which was previously developed by the applicant, involves the hydration reaction of water and a solid ice state, and cement powder and cement powder. This technology applies a technology in which cement is mixed and sprinkled around the ice, and then hardened as the ice melts.

Furthermore, this invention can also be applied to the construction of cast-in-place concrete piles. In other words, with conventional cast-in-place concrete, there is a risk that the unhardened concrete may separate into aggregate and cement when poured, and there is also a risk that consolidation in the ground may not be sufficient. Therefore, the present invention applies the above-mentioned means for mixing ice.

[Means for solving problems]

This invention involves mixing solid phase cement powder and solid phase granular ice at room temperature, adding aggregate to the granular ice with cement sprinkled around it, and introducing the mixed pile building material into the outer pipe. , and after driving the outer pipe to a predetermined depth, while pulling it up, the pile building material is forced into the ground using the inner pipe and compacted, and the water and cement produced by melting the granular ice are removed. This is a compaction pile construction method in which the materials are solidified into one piece through a chemical reaction.

〔Example〕

FIG. 1 to FIG. 4 show the process of creating a sand compaction pile, and the construction state will be explained based on the illustrated embodiment.

This invention is suitable for soft ground with soft viscosity or sandy ground with low density, and when dewatering and consolidation is not the objective.

First, as the pile building material 1 to be press-fitted into the ground, cement powder and granular ice are first mixed at room temperature, the cement powder is sprinkled around the granular ice, and then aggregate is mixed. The water-cement ratio is, for example, 20 to 30%. The equipment used may be the one used in the construction of conventional sand compaction piles, and consists of an outer pipe 2 and an inner pipe 3.

During construction, the required amount of the pile building material 1 is poured into the outer pipe 2 through the inner pipe 3, and the inner pipe 3 is struck to turn the ground improvement material 1 into a plug state, and the outer pipe 2 is driven to a predetermined depth. After that, while pulling up the outer pipe 2, the pile building material 1 is passed through the inner pipe 3.
is put into the outer pipe 2 and struck while moving the inner pipe 3 up and down, thereby forcing the pile building material 1 into the ground and compacting it.

By repeating the above press-fitting and compaction, a pile-like body is formed in the ground.

The mixed solid phase granular ice gradually melts and undergoes a hydration reaction with the cement, solidifying together with the sand and forming a sandpile of considerable strength.

Figures 5 to 8 show the construction process of cast-in-place concrete piles. First, granular ice obtained by crushing solid cement powder is used as the pile construction material 1 that is press-fitted into the ground. It is used by adding gravel and sand aggregate to the sprinkled material. The water-cement ratio is blended to be about 15 to 30%.

During construction, a shoe 4 is provided at the lower end of the outer tube 2 and driven together with the inner tube 3 to a predetermined depth, then the pile building material 1 is introduced, and the outer tube 2 is pulled up while being compacted with the inner tube 3. If necessary, the pile building material 1 is introduced after the reinforcing steel pipe 5 is inserted into the outer pipe 2.

〔Effect of the invention〕

This invention has the above-mentioned structure, and although solid granular ice with cement powder sprinkled around it is mixed in the sand, the press-in and compaction work is almost the same as when using only sand. . Moreover, since the granular ice is covered with cement, the granular ice does not melt immediately even at room temperature; after compaction, the granular ice melts, undergoes a hydration reaction with the cement, hardens together with the sand, and forms a mortar pile. Therefore, it is stronger than sand pile and less likely to be washed away by groundwater. Furthermore, since the water required for the hydration reaction can be obtained from the granular ice, the water-cement ratio is reduced and a homogeneous formulation can be achieved.

Furthermore, this invention can be applied to the construction of cast-in-place concrete piles. That is, a concrete pile can be made by using coarse aggregate such as gravel in addition to fine aggregate such as sand. Also in this case, the coarse aggregate, fine aggregate, and cement are sufficiently mixed and reliably press-fitted into the ground, making it possible to form a dense and homogeneous concrete pile.

[Brief explanation of drawings]

Figures 1, 2, 3 and 4 are sectional views showing an overview of the construction process of the present invention for creating sand piles, Figures 5, 6, 7 and 8.
The figure is a sectional view showing an outline of the construction process of the present invention for creating concrete piles. 1...Pile building material, 2...Outer pipe, 3...Inner pipe, 4...Sew, 5...Reinforcement bar.

Claims (1)

[Scope of Claims] 1. A pile building material made by mixing solid phase cement powder and solid phase granular ice at room temperature, adding aggregate with cement sprinkled around the granular ice, and removing the mixed pile building material. After the outer pipe is driven into the pipe and the outer pipe is driven to a predetermined depth, it is pulled up and the pile building material is forced into the ground using the inner pipe and compacted, and the water generated by melting the granular ice is removed. A compaction pile construction method that is characterized by causing a hydration reaction with cement to solidify them integrally. 2. The compaction pile construction method according to claim 1, wherein the aggregate is sand. 3. The compaction pile construction method according to claim 1, wherein the aggregates are coarse aggregate and fine aggregate.