JP3125244B2 - Ground improvement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a ground improvement method for improving a ground by injecting a ground improvement solidification material into the ground and forming a hardened body of the soil and the solidification material to improve the ground. The present invention relates to a method of constructing with a method with less influence.

[0002]

2. Description of the Related Art Conventionally, as a ground improvement method for improving a ground by injecting a ground improvement solidification material into a ground and forming a hardened body of the soil and the solidification material, an injection rod is inserted into a ground to be improved, Soil and slurry form by stirring with stirring blades, or deep mixing method to mix and solidify powder solidified material, solidified material slurry is injected into the ground at ultra high pressure,
A high-pressure injection stirring method for forming a hardened body while forcibly stirring the solidified material slurry and soil with the injection energy is widely used. In recent years, a construction method using both methods has been used.

[0003] However, these methods increase the volume of the ground by an amount corresponding to the amount of the solidified material injected, and the resulting lateral pressure displaces the surrounding ground and adversely affects nearby structures.

[0004]

In order to solve this problem, a screw is provided on the shaft of the rod to form a pouring rod formed in a screw auger shape, and the core portion is discharged by the screw auger portion. An improved method of soft ground has been proposed in which side pressure due to injection pressure at the time of solidification material injection is released to the inside to reduce lateral pressure displacement to the surrounding ground (Japanese Patent Publication No. 62-20329).

[0005] However, these methods for improving the board are all based on the earth discharging method using either the pouring rod, that is, the screw auger section when penetrating or lifting, and when the surrounding ground is in normal rotation, Only one of the pulling-side force (hereinafter referred to as the "pulling pressure") and the pushing-side force (hereinafter referred to as the "pushing pressure") in the case of reverse rotation acts, so that the expected displacement reduction effect can be obtained. May not be possible.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. The present invention has been made to rotate and vertically move an injection rod having a shaft body of a screw auger shape so that the injection rod can be penetrated. At the time of lifting or lifting, the screw auger part removes the original ground soil, creates a hardened body of soil and solidified material in the ground, and in the ground improvement method to improve the ground, the screw auger part rotates forward and reverse. Is also used to discharge the soil.

Another feature is that the forward rotation and the reverse rotation of the screw auger portion are appropriately performed by measurement of a measuring instrument such as a displacement meter.

Further, the present invention is configured to automatically control the rotation direction of the measuring device such as the displacement meter and the screw auger portion.

[0009]

[Action] In the case of a positive rotation of the screw auger portion of the injection rod penetrating into the ground to be improved, the tensile pressure acts inward due to the formed gap, thereby causing a tensile displacement inward. Occurs. In the case of reverse rotation of the screw auger part of the penetrated injection rod,
At the same time, a pressing force acts on the soil, so that an extruding pressure acts outward, which causes an outward displacement.

[0010] Therefore, by performing the earth removal by appropriately using the forward rotation and the reverse rotation of the screw auger part according to the situation, the tensile displacement and the extruding displacement are canceled out, and an excellent displacement effect can be obtained. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the soil improvement method of the present invention is applied to a high-pressure injection stirring method and the earth is discharged when the injection rod is pulled up will be described below with reference to the drawings. FIG. 1 is a side view of an embodiment in which the present invention is applied to a high-pressure injection stirring method, FIG. 2 is a pressure direction diagram in the case of normal rotation, and FIG. FIG.

In FIG. 1 to FIG. 3, reference numeral 1 denotes an injection rod provided with one system of a flow path (not shown). A stirring head 3 having a stirring blade 4 that is configured and extended in a lateral direction at a tip end portion of the injection rod is connected to a tip end of the injection rod 1.

On the other hand, a swivel 6 is attached to the upper part of the injection rod 1 to which a solidified material pressure feeding hose 5 communicating with the flow path of the injection rod 1 is connected. The injection rod 1 can be moved up and down by a driving device 8 guided by a column 7. At the tip of the stirring blade 4,
A nozzle 9 communicating with the flow path of the injection rod 1 is provided.

After the injection rod 1 configured as described above has penetrated to a predetermined depth in the ground 10 to be improved, the solidified material C is injected at a high pressure from the tip nozzle 9 of the stirring blade 4 and at the same time the core soil is rotated by the screw auger 2. Unload 10a 1
Pull up the injection rod 1 while 0b. As described above, when the injection rod 1 is pulled up, a large-diameter enlarged hardened layer A (injection stirring section) is formed by the injection of the solidified material and the stirring of the soil, and at the same time, in the core gap formed by the soil removal 10b of the core soil 10a. A part of the jet of the solidified material wraps around and flows in, and the core voids are formed in the core hardened layer B to prevent the unhardened portion of the enlarged hardened layer from being generated.

In this process, the displacement of the surrounding ground is continually measured by a measuring instrument (not shown) such as a displacement meter, and when the displacement occurs inward, the rotation of the screw auger is changed as shown in FIG. The displacement is canceled by generating the extrusion pressure E by reverse rotation. In addition, when the displacement occurs outward, as shown in FIG. 2, the rotation of the screw auger is rotated forward to generate the tensile pressure D to eliminate the displacement.

It is more effective to automatically control the rotation direction of the measuring device such as a displacement meter and the screw auger portion.

[0017]

According to the present invention, the solidified material is injected into the ground to be improved at a high pressure, and the solidified material and the soil are forcibly stirred by a stirring blade to form a hard solid in the ground. The side pressure generated by the amount of increase in the volume equivalent to the volume is discharged by appropriately using forward rotation and reverse rotation of the screw auger part of the injection rod, so that the tensile displacement generated by the tensile pressure and the pressing pressure As a result of canceling the generated pressing displacement, the effect of reducing the displacement applied to the surrounding ground can be obtained, and the adverse effect on the structure adjacent to the ground to be improved can be prevented.

[0018]

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment when the present invention is applied to a high-pressure injection stirring method.

FIG. 2 is a pressure direction diagram when the screw auger section is rotated forward.

FIG. 3 is a pressure direction diagram when the screw auger section is rotated in the reverse direction.

[Explanation of symbols]

1. Injection rod 10a. Core soil 2. Screw auger part 10b. 2. Core removal Stirring head A. 3. Expanded hardened layer (jet stirrer) Stirring blade B. Core hardened part5. Solidified material pumping hose C. Solidification material 6. Swivel D. 6. Tensile pressure Support E. Extrusion pressure 8. Drive device 9. Nozzle 10. Ground for improvement

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-115409 (JP, A) JP-A-4-360909 (JP, A) JP-A-61-5115 (JP, A) JP-A-57-115 51326 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) E02D 3/12

Claims (3)

(57) [Claims] An injection rod having a shaft body formed in a screw auger shape is rotated and moved up and down, and when the injection rod penetrates or is lifted up, the original ground soil is discharged by the screw auger portion and solidified in the ground. A soil improvement method in which a hardened body with a material is formed to improve the ground, wherein soil is removed using both forward rotation and reverse rotation of a screw auger part. 2. The ground improvement method according to claim 1, wherein the forward rotation and the reverse rotation of the screw auger portion are appropriately performed by measurement of a measuring device such as a displacement meter. 3. A ground improvement method of 請 Motomeko 2 wherein you characterized by automatically controlling the direction of rotation of the measuring instrument and the screw auger section such as the displacement gauge.