JP2004036388A - Method of preventing runoff of back-filling earth - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing runoff of back-filling earth, which is economical and forms an improvement body layer of a thin width compared with a conventional method in which temporary materials are employed, by infiltrating and injecting permanent grout from the beginning of work. <P>SOLUTION: According to the method, the back-filling earth is drilled by a rod for injecting a chemical solution along an earth preventive sheet 5, and the solvent-based permanent grout of a flash-setting type is injected from the tip of the rod, followed by drawing the rod. In this manner, grout injecting operation is repeatedly carried out to form a cutoff layer of the improved body 12 by chemical feeding, and thereafter the solvent-based permanent grout of a gradual-setting type is infiltrated and injected into the back-filling earth, to thereby form a hardened body 17 by chemical feeding. <P>COPYRIGHT: (C)2004,JPO

Description

(4) The present invention relates to a method for preventing backfill sediment outflow, which is effective in a case where a sandproof sheet for backfill sediment laid on a backfill stone of a seawall is damaged and the backfill sediment flows out.

Conventionally, for example, in a method of preventing suction of backfill soil when a sandproof sheet of backfill soil laid on a backfill stone of a caisson seawall is damaged, a backfill 20 as shown in FIG. There are a method of injecting a suspension-type drug solution 21 and a plastic-type drug solution, and a method of injecting a solution-type silica 22 having high permeability as shown in FIG.

However, a method of injecting a cement-based suspension-type chemical solution or a plastic-type chemical solution into the backing soil 20 does not provide a uniform strength when the fine powder content exceeds 5%. There was a danger that suction would occur.

Further, in the method of injecting the solution-type silica, since the viscosity of the chemical solution is low, the chemical solution may leak from a portion being sucked, and the improvement range may be smaller than the expected shape. Therefore, in order to solve the above-mentioned fear, the preliminary liquid is applied to the backfill soil 6 in the seawall 1 of the caisson 3 installed on the base rubble 2 facing the sea shown in FIG. A known example is known in which an infiltration and solidification liquid is injected into the backing soil 6 after injection from an injection hole along the line (for example, see Patent Document 1).
JP-A-2003-13437 (page 6, FIG. 1)

However, in the above-mentioned known example, although the broken portion 7 of the sandproof sheet is covered with a flash-setting plastic grout or the like, the flash-setting plastic grout has only a water glass type, and the water glass has no permanent property. Therefore, it is not economical because it is treated as a temporary material, and in the above-mentioned known example, there is a problem in economical efficiency because a plurality of holes for permeation injection are vertically formed.

The present invention uses a permanent grout material from the beginning to perform infiltration, thereby reducing the layer thickness of the improved body as compared with the case where a temporary material is used as in the conventional method, and furthermore, cutting for infiltration. By providing a hole obliquely along the sandproof sheet, a highly economical method of preventing backflow of backfill soil is provided.

The present invention provides a solution-type permanent grout material of a flash-setting type having a gel time of about 5 to 20 seconds, for example, after drilling with a rod for injecting a chemical solution along a sandproof sheet laid on a backing stone. A predetermined amount is injected, the rod is pulled up to a predetermined position, and the operation of injecting a predetermined amount of the solution-type permanent grout material is repeated for each predetermined position, and after forming a water blocking layer with a chemical liquid injection improving body covering the sandproof sheet, For example, the method comprises a method of preventing the outflow of the backing sediment by forming a layer of the solidified solid by injecting a solution-type permanent grout material of a slow-setting type in which the gel tom lasts for 6 to several tens of hours.

In addition, the present invention provides an improved body formed by injecting a chemical solution, comprising a method of preventing backfill earth and sand that is installed in one or more rows as necessary. It consists of a method of preventing backfill sediment using an injection method.

According to the conventional method, the damaged portion of the sandproof sheet was covered with the temporary setting type plastic grout of the temporary material, so that it could not be treated as a permanent improvement body. Since the covering chemical solution also uses a permanent grout material, it can be treated as a permanent improved body, and the layer thickness of the improved body by the injection of the chemical solution can be reduced, which is economical.

Also, in the conventional method, a plurality of holes for permeation injection are vertically formed. However, according to the present invention, since only one hole needs to be formed diagonally along the sand-proof sheet, it is more economical. It is.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

FIGS. 1, 2 and 3 show a procedure for stopping and injecting a chemical solution in a method for preventing the backfill sediment from flowing out to repair the sandproof sheet 5 having the damaged portion 7 along the sandproof sheet 5 laid on the backfilling stone 9. It is an explanatory view. First, in FIG. 1, a hole is drilled along a sandproof sheet 5 with a rod 11 for injecting a chemical. In this embodiment, a hole drilling water is used by using 20 to 30 l / min. Do.

Next, a predetermined amount of a solution type permanent grout material such as activated silica having a gel time of about 5 to 20 seconds is injected from the tip of the rod 11 installed in FIG. 2, and the improved body 12 is formed by solidification. Work.

Further, in FIG. 3, the rod 11 is pulled up to a predetermined length, and a solution-type permanent grout material is injected in a predetermined amount according to the procedure of FIG. 2 to continuously form a similar improved body 12, that is, pulling up the rod 11, Subsequently, the injection process for performing the same injection is repeated.

FIG. 4 is a schematic diagram showing a plan view of the improved body 12 for water-stop injection of permanent grout injected and solidified by the rod 11 in this case.

As the above-mentioned injection method, a two-tube single-phase injection method in which the two liquids of the liquid A and the liquid B are separated and pressure-fed using a double pipe until just before the confluence point, and gelled within a few seconds after the confluence, Using a double-tube or triple-tube boring rod as the injection tube, a multi-tube multi-phase injection system in which a quick-set type injection material is injected after a quick-set type injection material is injected can be used. However, the injection method is not particularly limited, and another injection method may be used.

Next, FIGS. 5, 6 and 7 are explanatory views of the procedure of performing the loosening-type chemical infiltration and injection performed subsequently to the above. As the chemical used, a loosening-type solution-type permanent grout material such as activated silica is used. The gel time was set to 6 to several tens of hours. In FIG. 5, the casing 14 was drilled along the improved body 12 on the improved body 12 formed by the water stoppage injection shown in FIG. Inject mold permanent grout material.

FIG. 6 shows a case where an injection pipe is installed. The tips of a plurality of injection pipes 15 are installed stepwise in an excavation hole, and the injection nozzles 16 at each end are injected into the sand ground at a low pressure.

In FIG. 7, after the above-mentioned injection, after a gel time of 6 to several tens of hours, a permeation injection improved body 17 of a solution type permanent grout material is formed. A plan view is shown in FIG.

In this method of chemical injection, if the super multi-point injection method is used by drilling diagonally, an ideal solid body close to a sphere can be obtained by injecting the chemical slowly and gradually between the earth and sand particles. As a result, ideal penetration and high workability can be achieved at the same time. However, other methods may be used as long as the penetration is performed by other chemical liquid injection methods.

FIG. 9 is a cross-sectional view of the revetment 1 constructed by the method for preventing backfill sediment runoff of the present invention, and shows a foundation rubble 2, a caisson revetment 3, a backfill stone 9, and a backfill sediment 6, The improved body 12 and the improved permeation-injected body 17 for water stoppage are formed along the sandproof sheet 5, respectively.

Embodiments of the present invention include structures facing sea, that is, seawalls, structures constructed of sheet piles, caisson, blocks, PC members, stone materials, cast-in-place concrete, etc., as well as retaining facilities, piers, quays, etc. There is a possibility to use.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of the piercing | piercing work which stops and injects the instantaneous-type chemical | medical solution explaining the procedure of the construction method of this invention. FIG. 2 is a schematic diagram showing creation of an improved body by an injection work from the rod tip of FIG. 1. FIG. 3 is a schematic view showing an injection work after the rod is pulled up in FIG. 2. It is a top view which shows the improved body of FIG. FIG. 4 is a schematic diagram of a drilling operation using a casing of a loose-binding type chemical liquid permeation injection after the injection operation of FIG. 3. It is the schematic which used the injection | pouring pipe installation for the chemical | medical solution permeation | injection injection of FIG. It is the schematic which formed the permeation | implantation improvement body by the permeation | infusion of FIG. 5 and FIG. It is a top view which shows the permeation | implantation improvement body of FIG. It is sectional drawing of the revetment improved by the method of this invention. It is sectional drawing which shows the conventional method of preventing suction of backfill soil. It is sectional drawing which shows the suction prevention method of the backfill of the other conventional example different from FIG. It is sectional drawing of the method of preventing the suction of backing soil of the conventional well-known example.

Explanation of reference numerals

Reference Signs List 5 sandproof sheet 9 backing stone 11 rod 12 chemical liquid injection improved body 17 permeation injection solidified body

Claims (3)

After drilling with a rod for chemical liquid injection along the sandproof sheet having a damaged part laid on the backing stone, a predetermined amount of instantaneous solution type permanent grout material is injected from the end of the rod, and the rod is inserted into a predetermined amount. The operation of injecting a predetermined amount of the solution-type permanent grout material to a predetermined position is repeated for each predetermined position to form a water-stopping layer with a chemical solution-improved body covering the sandproof sheet, and then a loose-setting type solution-type permanent grout material A method for preventing the backfill soil from flowing out by forming a layer of a solidified body by injecting a liquid. The method according to claim 1, wherein the improved body formed by injecting the chemical solution is installed in one or more rows as necessary. 3. The method for preventing runoff of backfill soil according to claim 1 or 2, wherein the method of injecting the chemical solution is to use a multipoint injection method by obliquely drilling holes.

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