JP2013087603A - Immersion method for caisson - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an immersion method for caisson with extremely excellent workability that cannot only reduce peripheral surface friction, but also bring a caisson into contact with a foundation as before without the need to completely replace a skid with a cured material, and can exhibit peripheral surface frictional force equal to or larger than that of the current foundation.SOLUTION: There is provided the immersion method for caisson that immerses a caisson 1 in a foundation 2, the method includes making the caisson 1 sink while injecting a konjak-like filler between the foundation 2 and caisson 1 using an injection pipe 4; then injecting a grout material from the injection pipe 4 and mixing it with the konjak-like filler; and bringing a mixture 3 of the konjak-like filler and the grout material, the caisson 1, and the foundation 2 into contact with one another.

Description

  The present invention relates to a caisson setting method.

  The caisson foundation is known as one of the foundations of the structure. The caisson foundation is constructed by making a box (caisson) on the ground and sinking it while excavating the soil at the bottom.

  By the way, when sinking the caisson, there is a possibility that it will not sink to a sufficient depth due to the frictional force between the caisson outer periphery and the soil (ground), and various friction reducing methods for reducing this friction have been proposed.

  For example, as a conventional friction reducing method, a method of injecting a lubricant such as bentonite slurry between the outer peripheral surface of the caisson and the ground is known, but when these lubricants are used, after the caisson sinks In order to ensure the stability of the foundation, it is necessary to replace the cured material with excellent adhesion to the caisson (see Patent Document 1).

JP-A-8-158378

  In view of the present situation as described above, the present invention can reduce the friction on the peripheral surface as in the prior art, as well as allow the caisson and the ground to be in close contact with each other without having to completely replace the lubricant with the hardened material. It is intended to provide a caisson laying method that is capable of exerting a peripheral frictional force equivalent to or better than that of the present invention and has excellent workability.

  The gist of the present invention will be described with reference to the accompanying drawings.

  A caisson settling method for sinking the caisson 1 to the ground 2, after the caisson 1 is submerged while injecting the konjac filler between the ground 2 and the caisson 1 using the injection pipe 4, Injecting a grout material from the injection tube 4 to mix the konjac filler and the grout material, and bringing the mixture 3 of the konjac filler and the grout material, the caisson 1 and the ground 2 into close contact. This relates to a caisson laying method characterized by the above.

  2. The caisson settling method according to claim 1, wherein a coating material made of an organic polymer is applied to the peripheral wall surface of the caisson 1.

  The caisson settling method according to any one of claims 1 and 2, wherein the grout material is cement milk.

  The caisson deposition method according to any one of claims 1 to 3, wherein the konjac filler is made of an organic polymer.

  Further, in the caisson settling method according to any one of claims 1 to 4, the caisson settling method is characterized in that the grout material is mixed with the konjac-like filler in an equal amount or more. is there.

  Since the present invention is as described above, the peripheral friction can be reduced as in the conventional case, and the caisson and the ground can be brought into close contact with each other without having to completely replace the lubricant with the hardened material. It is a caisson laying method that can exhibit the above-described peripheral frictional force and has excellent workability.

It is a schematic explanatory sectional drawing of a present Example.

  An embodiment of the present invention which is considered to be suitable will be briefly described with reference to the drawings showing the operation of the present invention.

  After caisson 1 was sunk while injecting konjac filler between ground 2 and the peripheral wall surface of caisson 1, grout material was injected from injection tube 4 used when injecting konjac filler. The konjac filler and the grout material are mixed, and the mixture 3 of the konjac filler and the grout material, the caisson 1 and the ground 2 are brought into close contact with each other.

  At this time, since the friction between the outer peripheral surface of the caisson 1 and the ground 2 is reduced by the konjac filler, the caisson 1 can be easily sunk to the required depth.

  Also, instead of replacing all the konjac filler, a grout material such as cement milk is injected from the same injection tube 4 as the konjac filler, and the konjac filler and the grout material are mixed to form a konjac shape. The friction reducing effect of the filler is reduced (or lost), and the mixture 3 that exhibits sufficient frictional force, the caisson 1 and the ground 2 are securely brought into contact with each other, and the peripheral frictional force is equal to or greater than that of the local board. Therefore, it is possible to construct a stable caisson foundation.

  Specific embodiments of the present invention will be described with reference to the drawings.

  The present embodiment is a caisson setting method in which the caisson 1 is set on the ground 2, and the caisson 1 is injected while injecting the konjac filler between the ground 2 and the caisson 1 using the injection pipe 4. After sinking, a grout material is injected from the injection tube 4 to mix the konjac filler and the grout material, and the mixture 3 of the konjac filler and the grout material 3, the caisson 1 and the ground 2 is closely attached.

  In this embodiment, for example, as shown in FIG. 1, the injection port 4 for injecting the konjac filler and grout material with the discharge port directed toward the caisson circumferential surface side, and the discharge port directed toward the ground bottom surface side. The caisson 1 including the blow pipe pipe 5 for blow and the placing pipe 6 for placing concrete between the bottom of the ground and the bottom of the caisson is laid (embedded). The injection pipe 4 is provided such that a plurality of discharge ports are arranged at predetermined intervals in the circumferential direction and the axial direction of the caisson 1. Each tube is provided with a necessary number at appropriate intervals depending on the size of the caisson 1 and the like. The code | symbol 7 is a pump which inject | pours a filler and grout material.

  In addition, the konjac filler (gel filler) of this example is made of an organic polymer, and for example, it is gelled by adding an inorganic gelling agent to a polymer mainly composed of an organic polymer. The formed konjac material can be employed.

  As the polymer for forming such a konjac-like substance, a water-soluble polymer containing a mannose residue in the molecule, preferably, for example, a water-soluble polymer such as plant mucilage can be used. . By adding a gelling agent to an aqueous solution of this water-soluble polymer with additives such as boric acid added as necessary, it can be easily made into a konjac-like substance. In addition, as an inorganic type gelatinizer, sodium hydroxide, slaked lime, sodium carbonate, etc. are employable, for example.

  Moreover, as a vegetable mucilage which is a preferable water-soluble polymer, guagamum or a modified product thereof, a roast bean gum or a natural polymer mainly composed of a galactomannose polymer can be used alone or in combination. These vegetable mucilages are controlled by alkaline substances such as sodium hydroxide, slaked lime and sodium carbonate as gelling agents, and acidic substances such as sulfate bands, aluminum chloride, dilute sulfuric acid and dilute hydrochloric acid as degelling agents. And easy to handle. In this example, the pH of the konjac filler is set to about 7.0 ± 0.5 (neutral).

  In this embodiment, a coating material (manicure material) made of a known organic polymer (neutral) is applied to the peripheral wall surface of the caisson. By using this nail polish material and konjac filler together, an extremely excellent friction reducing effect is exhibited.

  In this embodiment, cement milk (milk-like product made by mixing cement and water) is used as the grout material. The blending amount of cement and water is appropriately set according to the kind of ground and softness.

  In addition, the grout material is mixed with the konjac filler in the same amount or more (volume ratio). In this embodiment, the konjac filler and the grout material are mixed at a ratio of 1: 1. When the amount of the grout material injected is small, the friction reducing effect of the konjac filler cannot be sufficiently reduced. Therefore, it is preferable to inject and mix the grout material so as to be at least the above ratio. In addition, by injecting cement milk using the same injection tube 4 as the konjac-like filler, both are appropriately mixed without any particular stirring or the like.

  Also, from various experiments, the konjac filler according to this example is advantageous compared to the conventional bentonite, which is less likely to penetrate into the ground under a low restraint pressure, and is excellent in the initial friction reduction effect and low restraint. It was found that the sandy ground of the pressure has the characteristics of excellent sustainability, and that the nail polish is used in combination with the konjac filler to enhance the friction reduction effect. Further, it was found that by mixing the grout material into the konjac filler, the strength was recovered (friction force was recovered) to a higher level than when no lubricant was used.

  Since the present embodiment is as described above, when the caisson 1 is sunk, the friction between the outer peripheral surface of the caisson 1 and the ground 2 is reduced by the konjac filler, so that the caisson 1 is brought to a necessary depth. Can be easily sunk.

  Also, instead of replacing all the konjac filler, cement milk is injected from the same injection tube 4 as the konjac filler, and the konjac filler and the cement milk are mixed together, whereby the friction of the konjac filler is mixed. Construct a stable caisson foundation by ensuring that the mixture 3 of konjac-like filler and cement milk that can exert sufficient frictional force is reduced (lost) and caisson 1 and ground 2 are in close contact with each other. It becomes possible to do.

  Therefore, the present embodiment can reduce the friction on the peripheral surface as in the conventional case, and also allows the caisson and the ground to be in close contact with each other without having to completely replace the lubricant with the hardened material. This is an excellent method for laying caisson.

1 Caisson 2 Ground 3 Mixture 4 Injection pipe

Claims (5)

  A caisson settling method in which a caisson is set in the ground, the konjac filler being poured between the ground and the caisson using an injection pipe, the caisson being submerged, and then a grout material from the injection pipe The konjac filler is mixed with the grout material, and the mixture of the konjac filler and the grout material, the caisson and the ground are brought into close contact with each other.   2. The caisson deposition method according to claim 1, wherein a coating material made of an organic polymer is applied to a peripheral wall surface of the caisson.   5. The caisson settling method according to claim 1, wherein the grout material is cement milk.   4. The caisson settling method according to claim 1, wherein the konjac filler is made of an organic polymer.   5. The caisson deposition method according to claim 1, wherein the grout material is mixed in an equal amount or more with the konjac filler.

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