JP3285163B2 - Water stopping method and water stopping mechanism in foundation pile hole for ground reinforcement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a mechanism for stopping water in a foundation pile hole in a ground reinforcement means for strengthening the foundation by driving a foundation pile into a foundation pile hole drilled in soft ground. About.

[0002]

2. Description of the Related Art When constructing various structures on soft ground, a deep foundation pile hole is drilled in the ground with an excavator, and a foundation pile made of concrete, hard synthetic resin or the like is bored in the hole. A method of casting and solidifying the periphery of the pile with a pile fixing liquid such as bentonite or clay to strengthen the ground is used.

[0003] When the ground is strengthened by the foundation pile as described above, usually, a deep foundation pile hole is drilled by an excavator.
While placing the foundation pile in the hole, a foundation solution such as cement milk is injected into the vicinity of the bottom of the hole, and a pile circumference fixing solution of soil cement is injected into the upper part of the foundation pile so that the foundation pile is in the hole. It is fixed to.

That is, the excavator is provided with a cutter bit at the tip of a long shaft rotated and driven by a motor, and the cutter bit is fixed to the outer periphery of the shaft up to the support layer at the bottom of the foundation pile hole. The crushed stone is discharged through the spiral auger.

[0005] When the cement milk led out of the hollow shaft from the tip of the cutter bit is poured out, the cutter bit rises by that much and then the soil cement is injected, and the bit further rises.

[0006]

The foundation pile hole is
If the ground is soft, its depth may range from 30m to 60m. When performing foundation pile driving at such a large depth, it is difficult to confirm the soil state of the support layer that supports the consolidation liquid injected near the bottom of the hole and the flow of water because of the large depth. is there.

For this reason, when a flowing water layer or a permeable layer is present in the support layer, the consolidation liquid flows out of the foundation pile hole into the flowing water layer or the permeable layer to increase the injection amount of the consolidation liquid. In addition, the injection amount cannot be determined, and furthermore, the solidification of the consolidation liquid causes cavities to be formed or solidifies into a porous shape, resulting in a problem that a solid consolidation layer of the foundation pile cannot be obtained. Existed.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the object of the present invention is to place a foundation pile in a deep hole having a depth of 30 m to 60 m, especially in a support layer of a consolidation liquid. It is an object of the present invention to provide a method and a mechanism for stopping water from a foundation pile hole, which can prevent leakage of water, obtain a strong support layer, and reduce the amount of root compaction liquid used.

[0009]

According to the present invention, a fine water-absorbing polymer particle is injected into a support layer of a consolidation liquid near the bottom of the pile hole, and the polymer is dispersed in the consolidation liquid support layer. The first gist is that water is distributed in the support layer in a state where water is absorbed and swollen, and the second gist is that the fine-grained polymer can be injected before the injection of a consolidation liquid or can be consolidated. Mixed with a liquid and injected into the consolidation liquid support layer .
We propose a water stop method.

[0010] Further, as a preferred means of the present invention, there is provided a soil improvement means for strengthening the ground by solidifying a foundation pile driven into a foundation pile hole drilled in a soft ground by an excavator with a fixing agent. Proposes a water-stopping mechanism by injecting a water-absorbing polymer in which a core material having a higher specific gravity than water, such as metal chips and grain sand, is entrapped with a polymer in the support layer of the consolidation liquid injected into the bottom of the hole I do.

[0011]

According to the present invention, for example, the particle size of the dried fine-grained water-absorbing polymer is set to a particle size in consideration of the water absorption time of the polymer and the injection operation time of the consolidation solution, and this is used as the consolidation solution. The water-absorbing polymer is supported by mixing or injecting through a shaft of an excavator into the support layer of the consolidation liquid near the bottom of the hole, and penetrating the water-absorbing polymer into the support layer. It absorbs and swells the water in the layer and distributes it in the support layer, thereby preventing the root compaction liquid from leaking into the ground.

More specifically, at the time of driving a concrete foundation pile, the fine-grained polymer is pressed into the lowermost portion of the pile before the consolidation liquid flows down or together with the consolidation liquid, whereby the flowing layer of the support layer and the water permeability are formed. The polymer is filled into the permeation gap of the layer of gravel. In this case, since the water absorption time varies depending on the size of the polymer particle size, the particle size of the granular polymer is set in consideration of the pile driving depth consolidation liquid inflow operation time. For example, a particle size of 20 μm to 100 μm absorbs about 30 to 100 times its own weight of water in water within 2 to 3 seconds. The swelling effect of delaying the time cannot be expected. Therefore, if the diameter of the particles is 0.5 to 2 mm, if the polymer absorbs 80 to 400 times the water, it absorbs 400 times. If the diameter is 0.5 to 1 mm, the polymer absorbs water to the center and swells. It takes about 10 to 20 minutes to swell to 4φ to 7φ.
In addition, the one with a diameter of 1.0 to 2.0 φ takes about 20 to 50 minutes,
Swell to a diameter of 7φ to 10φ. By taking advantage of this, the liquid inflow operation time is measured, and the polymer swells at the stage when the polymer is filled into the permeable gap of the gravel of the support layer and the permeable layer, and adheres to the gap to perform the sealing action of the multilayer. Can be done.

Therefore, according to the present invention, at the beginning of the press-fitting of the gravels of the permeable layer into the permeable gaps, the polymer can enter any gaps due to the small diameter of the polymer, and absorb water 400 times more. After that, it becomes a spherical gel-like sphere and fills the gap in a state like an ikura, so that the sealing action of the multilayer can be performed. Further, by forming the water-absorbing polymer such that the core wraps the metal piece or grain sand or other heavy water having a higher specific gravity than water with the polymer, the weight of the water-absorbing polymer increases, and the polymer in the foundation pile hole is increased. Ascent is prevented. Also, pack the polymer and sand into a water-permeable net pouch or melted paper pouch and push it in first.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. However, the types, shapes, dimensions, materials, and other relative usages of the constituent members described in the following examples limit the scope of the present invention to only those components unless otherwise specified. It is not a gist, but merely a description example.

FIG. 1 shows the working sequence of the method of the present invention. In the figure, reference numeral 1 denotes an excavator, which is an electric motor 11 which is a driving source, and which is rotationally driven by the motor 11 and has a fixed liquid at its center. A shaft having a central hole for injection is provided.

On the outer periphery of the shaft 11, stirring blades 13 in the foundation pile hole are fixed at substantially equal intervals in the longitudinal direction, and at the lower portion (tip end) of the stirring blades 13 are spirals for discharging crushed stone. An auger 14 is fixedly provided. Reference numeral 15 denotes a cutter bit for excavation provided at the tip of the shaft so as to be rotatable integrally with the shaft, and 16 denotes a coupling. Since such a configuration is known, a detailed description thereof will be omitted.

Next, the water stopping method of this embodiment will be described in detail. [Procedure 1] FIG. 1 (A) The shaft 12 and the cutter bit 15 of the excavator 1 are
It is rotationally driven by a motor 11 to excavate the foundation pile hole 2 to the support layer 3 at the bottom. In this case, 300 to 6 piles
In the case of a diameter of 00φ, the diameter of the excavation hole is preferably 400 to 700φ.

Next, when the excavation of the foundation pile hole 2 is completed,
The water-absorbing polymer 4 having a small diameter (particle diameter: 1 mm to 2 mm) is mixed with water or a consolidation liquid, and is introduced from the center hole (not shown) of the shaft 12 into the support layer 3 at the bottom of the shaft from the tip of the cutter bit 15. Gushing. Thereby, the support layer 3
Is filled with the polymer 4 having a small particle size that has not completely absorbed water. A technique may be used in which fine sand is entangled with the polymer and the polymer is submerged. Avoid floating in muddy water.

The water-absorbing polymer 4 swells by absorbing the surrounding water over time. As a result, the support layer 3 is clogged with the polymer 4 which has absorbed water and swelled to 80 to 400 times that of the dried state, thereby forming a water blocking wall.

The water-absorbing polymer 4 is described in, for example,
As shown in -264803, an acrylic copolymer is dissolved in an aliphatic hydrocarbon, acrylic acid and an aqueous solution of an alkali metal salt thereof are dispersed, and reverse-phase suspension polymerization is performed.
It is manufactured by crosslinking with a crosslinking agent in the presence or absence of an inorganic substance and drying.

Since the water absorbing time of the water-absorbing polymer 4 produced as described above varies depending on the size of the particle size, an operation for injecting a below-described root compaction liquid into the bottom of the foundation pile hole 2 is performed. It is necessary to set the particle size in consideration of time.

For example, the particle size of the water-absorbing polymer 4 is 20 μm.
In the case of m to 100 μm, the polymer absorbs about 30 to 100 times its own weight in water in 2 to 3 seconds, so that when the polymer reaches the support layer 3 of the foundation pile hole 2, it already swells. Thus, the swelling effect after reaching the support layer 3 cannot be obtained.

Therefore, when the particle size of the polymer 4 is made larger than the above-mentioned value and the time until swelling is measured, the following result is obtained. For example, when the particle size is 0.5 to 1 mm and absorbs 400 times of water, the time until swelling is 10 to 20 minutes and 4 m
Swell to a particle size of m to 7 mm. The particle size is 1mm ~ 2mm
When absorbing 400 times the water in, the time to swell is 20
In 50 minutes, it swells to a particle size of 7-10 mm.

If the water-absorbing polymer 4 has the above-mentioned particle size, that is, 0.5 mm to 2 mm, it will swell for an appropriate time (10 to 50 minutes) after reaching the support layer 3 and The particle size also becomes a sufficient size of 4 mm to 10 mm, which can form a water blocking wall while filling the gap in the support layer 3. It is possible to see the time margin before the cement milk is injected.

[Procedure 2] FIG. 1 (B) Before all the water-absorbing polymer 4 in the support layer 3 injected as described above swells (when the particle diameter is 1 mm to 2 mm, the time until swelling is After 20 to 50 minutes, but with some unabsorbed polymer remaining), the root compaction liquid 5 is injected through the shaft 12 from its tip.

Next, while the shaft 12 is rotated and pulled upward, a pile periphery fixing solution (for example, a soil pile periphery fixing solution) 6 is injected, and when the pile periphery fixing solution 6 reaches a predetermined amount, the shaft 12 is rotated.
Pull out upwards. Thereby, the inside of the pile hole 2 is as shown in FIG.
As shown in (B), a root consolidation liquid 5 (milk cement) is provided on the bottom, and a pile circumference fixing liquid 6 (soil cement) is provided on the top.
Will be enclosed.

Since the swollen water-absorbing polymer 4 is filled in the support layer 3 around the consolidation liquid 5, this becomes a water blocking wall, and the consolidation liquid 5 does not leak into the support layer.

[Procedure 3]... (C) of FIG. 1 Next, the pile circumference fixing liquid 6 is injected. Thereafter, the shaft 12 of the excavator 1 is pulled up, and the pile driving machine 31 rotates the foundation pile 32 such as a concrete pile or a resin pile into the pile periphery fixing liquid 6 and the root consolidation liquid 5 in the foundation pile hole 2. While driving. FIG. 1C shows a state immediately before the foundation pile 32 is inserted into the pile fixing liquid 6.

[Procedure 4] When the foundation pile 32 is inserted to a predetermined position in the consolidation liquid 5 in FIG.
Due to the volume of the pile 32, the root compaction liquid 5 and the pile peripheral fixing liquid 6 rise along the outer peripheral surface of the pile 32, and the pile 32 is fixed at a predetermined depth. This state is shown in FIG. Usually, the root compaction liquid 5 solidifies in 2 to 3 hours, and the pile fixation liquid 6 solidifies in 2 to 3 days.

The water-absorbing polymer may be used as a single polymer, or may be a water-absorbing polymer obtained by encapsulating a core material having a higher specific gravity than water, such as metal pieces or grain sand, with a polymer. For example, as shown in FIG.
A core material 41a made of a metal piece, grain sand, or the like is disposed on a core portion, and is formed by enclosing the core material 41a with a polymer material 41b. In this case, as compared with the case of using only the polymer material, the specific gravity is increased substantially by the amount of the core material 41a. When this water-absorbing polymer 41 is used, the specific gravity of the polymer increases, so that it is possible to prevent the polymer 41 from floating from the support layer 3 at the time of injection.

[0031]

As described above, according to the present invention, by injecting the water-absorbing polymer into the support layer of the consolidation liquid, the polymer absorbs and swells the water in the water-permeable layer, and swells in the support layer. This serves as a water-blocking wall on the side of the consolidation liquid, which can prevent the consolidation liquid from leaking into the support layer. This makes it possible to obtain a strong water-blocking wall and significantly reduce the amount of the root compaction liquid by an extremely simple operation of only injecting the water-absorbing polymer when excavating the foundation pile hole.

According to the present invention, the foundation pile driving of a deep building is carried out under the circumstance where the boring method using a drill bit occupies most by eliminating the environmental noise, and the time required for the pile driving is shortened and the underground pile driving foundation is ensured. It is possible to satisfy the social demands for the assurance of the construction method, and since the present invention can be incorporated into the steps of the flow of the existing construction method, it is extremely economically effective. And so on.

[Brief description of the drawings]

FIG. 1 is an operation procedure diagram showing a procedure of a construction example of the present invention.

FIG. 2 is a schematic view showing one embodiment of a water-absorbing polymer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Excavator 12 Shaft 15 Cutter bit 2 Foundation pile hole 3 Support layer 4 Water-absorbing polymer 41 Water-absorbing polymer 41a Core material 5 Root fixation liquid 6 Pile perimeter fixing liquid 31 Pile driving machine 32 Foundation pile

Claims (2)

(57) [Claims] 1. An excavator drilled in soft ground.
Fixing foundation piles placed in foundation pile holes such as concrete piles
When strengthening the ground by hardening at the bottom, near the bottom of the foundation pile hole
Water absorption selected to a specified particle size in the adjacent consolidation liquid support layer
Injecting a polymer, the support layer and the water-absorbing polymer
Absorbs and swells the water in the vicinity, in the ground of the root compaction liquid
Prevent leakage toAlong with Inject fine-grained polymer before injecting the consolidation liquid,
Alternatively, the finely divided polymer is mixed with
Inject into the solidification liquid support layer For strengthening the ground
Water stopping method in foundation pile hole. 2. A base drilled in soft ground by an excavator.
Strengthen the ground by fixing the foundation pile placed in the foundation pile hole with fixing agent
In the ground improvement means to be injected into the bottom of the foundation pile hole
In the support layer of the root compaction liquid,
Water-absorbing polymer made by encapsulating a heavy core material with a polymer
Foundation pile hole for soil reinforcement characterized by injecting
Water stop mechanism in the.