JP5132701B2 - Construction method of columnar ground improvement body - Google Patents

Description

  The present invention relates to a method for constructing a columnar ground improvement body.

  Patent Document 1 describes a method for constructing a ground improvement body that effectively uses construction generated soil. The method of Patent Document 1 pushes a casing, which is a columnar body, into the ground, throws the improved soil obtained by improving the construction generated soil into a cavity in the casing, and then releases the improved soil from the tip (lower end) of the casing. The casing is pulled out.

Japanese Patent No. 4092411

  In the method of Patent Document 1, it is necessary to prepare an improved soil production plant for kneading the construction-generated soil and the solidified material, which may increase the equipment cost.

  Moreover, in the method of patent document 1, there exists a problem that the columnar ground improvement body larger than a casing (columnar ground improvement body with a larger outer diameter or length than a casing) cannot be constructed | assembled. When constructing a columnar ground improvement body with a large outer diameter, it is necessary to use a large-diameter casing according to the diameter of the columnar ground improvement body. In this case, not only the casing but also this is inserted and removed. Since the construction machine for this purpose is also enlarged, the construction cost may be high.

  From this point of view, the present invention is a method for constructing a columnar ground improvement body using construction generated soil, and it is possible to treat the construction generated soil on-site without using a special construction machine. It is an object of the present invention to provide a method capable of constructing a columnar ground improvement body that is larger than a hole into which construction generated soil should be introduced.

  The method for constructing a columnar ground improvement body according to the present invention includes an insertion step of inserting a columnar body into the ground, a pulling up step of pulling up the columnar body from the ground, and a construction occurring in a hole left in the trace of the columnar body being lifted A mixing soil mixing step of inserting soil into the hole, and mixing the solidified material discharged from the stirring means with the ground around the hole and the construction generated soil. And a process.

  In the present invention, construction generated soil is a general term for surplus materials generated during construction work or dismantling work. For example, excavated residual soil (including gravel and sludge) discharged during various construction work, creation work This includes the residual soil that is generated in the area and the demolition of concrete and asphalt.

  According to the present invention, since the construction generated soil can be processed in the field without using a special construction machine, the construction generated soil can be effectively used inexpensively and easily. In addition, according to the present invention, the construction generated soil put into the hole left after the columnar body is pulled up (that is, the hole in which the hole wall is exposed) is mixed with the solidification material together with the ground around the hole. Therefore, the outer diameter of the columnar ground improvement body is larger than the bore diameter (outer diameter of the columnar body). In addition, if the stirring means is inserted to a position deeper than the deepest part of the hole, it is possible to construct a columnar ground improvement body that is longer than the depth of the hole.

  There is no restriction on the method of inserting the columnar body. Depending on the ground conditions, etc., it may be selected from rotational press-fitting, vibration press-fitting, non-vibration press-fitting and the like.

  There is no restriction | limiting also in the structure of a columnar body. The columnar body may be configured using a cylindrical body whose front end (lower end) is closed, or the columnar body may be configured using a solid bar. Moreover, you may provide a screw etc. in the outer periphery of a columnar body.

  When a columnar body is configured using a cylindrical body, the inserting step may be performed with the tip of the cylindrical body closed, and the pulling step may be performed with the distal end of the cylindrical body open. When the pulling process is performed with the tip of the cylinder open, it is possible to suppress a decrease in the cavity volume at the bottom of the hole.

  In addition, as a stirring means, the mechanical stirring type stirring means provided with the stirring blade is typical, for example.

  According to the present invention, construction generated soil can be processed in the field without using a special construction machine. It is also possible to construct a columnar ground improvement body that is larger than a hole into which construction-generated soil is to be poured (that is, a columnar body used when forming the hole).

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram explaining the construction procedure of the construction method of the columnar ground improvement body which concerns on embodiment of this invention, Comprising: (a) is a figure corresponding to an insertion process, (b) is a figure corresponding to a raising process, (c ) Is a diagram showing a hole left in the trace of lifting the columnar body. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram explaining the construction procedure of the construction method of the columnar ground improvement body which concerns on embodiment of this invention, Comprising: (a) is a figure corresponding to a generated soil injection | throwing-in process, (b) is a figure corresponding to a mixing process, (C) is a figure which shows a columnar ground improvement body.

  A method for constructing a columnar ground improvement body according to an embodiment of the present invention is a method for constructing a columnar ground improvement body 5 (see FIG. 2C) using construction-generated soil, and the columnar body 10 is grounded. 1 (see (a) of FIG. 1), a pulling up process (see (b) of FIG. 1) for pulling up the columnar body 10 from the ground 1, and a generated soil for introducing the construction generated soil 3 into the hole 2 A charging step (see FIG. 2A), a mixing step of mixing the solidified material and the construction generated soil 3 (see FIG. 2B).

  In the insertion step, as shown in FIG. 1A, the upper end portion of the columnar body 10 is connected to a general-purpose base machine (not shown) for improving the columnar ground, and the rotational force and the downward direction are applied to the columnar body 10. The columnar body 10 is rotationally press-fitted into the ground 1 by applying a force.

  Although there is no restriction | limiting in the structure of the columnar body 10, The thing of this embodiment is provided with the hollow cylinder 11 and the front-end | tip cap 12 which obstruct | occludes the front-end | tip (lower end) of the cylinder 11. FIG. A spiral screw 13 projects from the outer peripheral surface of the cylinder 11. The tip cap 12 has a tapered shape (conical shape or polygonal pyramid shape), but the one in this embodiment is divided into a plurality of pieces 12a, 12a,. To do. The piece 12a is connected to the lower end of the cylinder 11 via a hinge. When the tips of the pieces 12a, 12a,... Gather on the central axis of the columnar body 10, the tip of the cylinder 11 is blocked. When the tips of the pieces 12a, 12a,... Are separated, the tip of the cylinder 11 is opened (opened) (see FIG. 1B). The taper angle of the tip cap 12 may be set as appropriate in accordance with the properties of the ground 1, but is preferably set in a range of approximately 10 to 30 degrees.

  If the columnar body 10 is pushed into the ground 1 while rotating the columnar body 10 in one direction with the cylindrical body 11 closed, the ground 1 around the tip cap 12 is pushed away to the side. A high density area (peripheral ground 1a) is formed. That is, by inserting the columnar body 10, the ground 1 is compressed (consolidated) and compacted toward the side. In addition, although the residual soil is discharged | emitted with the rotary press injection of the columnar body 10, the amount is a little compared with the cavity volume of the hole 2.

  When the tip of the columnar body 10 reaches a desired depth, the process proceeds to a pulling process as shown in FIG. In the pulling process, the columnar body 10 is pulled upward while being reversed.

  When the columnar body 10 is pulled up, the tips of the plurality of pieces 12a, 12a,... Are naturally separated, and the tip of the cylindrical body 11 is opened. If the columnar body 10 is pulled up while the tip of the cylinder 11 is closed, the bottom of the hole 2 is in a negative pressure state, and so-called suction (a phenomenon in which the hole wall collapses and the hole diameter decreases) may occur. If the columnar body 10 is pulled up with the tip of the cylinder 11 open, the generation of suction can be suppressed.

  As shown in FIG. 1 (c), the hole 2 remaining in the trace after the columnar body 10 is pulled up is in an unearthed state, but since the surrounding ground 1a is compacted, The wall is self-supporting.

  When the pulling process is completed, as shown in FIG. Although there is no restriction on the method of charging the construction generated soil 3, for example, if the hopper 30 is placed in the upper end opening of the hole 2 and then the construction generated soil 3 is loaded into the hopper 30 using a heavy machine (not shown). Good. Of course, there is no problem even if the remaining excavated soil generated in the insertion process is introduced.

  If the construction soil 3 is filled in the hole 2, the process proceeds to the mixing step as shown in FIG. The mixing step is performed using the stirring means 20.

  Although there is no restriction | limiting in the structure of the stirring means 20, The thing of this embodiment is equipped with the mechanism etc. which stir and mix a solidification material and earth and sand, etc. which discharge a solidification material. That is, the agitation means 20 includes the hollow rod 21 that is a drilling shaft and a supply path for the solidified material, the stirring blade 22 for stirring and mixing the solidified material, the construction generated soil 3, and the like, as well as the drilling blade 23 and the co-rotation prevention. A wing 24, a shredded wing 25, and the like are provided. The co-rotation preventing wing 24 is wider than the excavating wing 23 and does not rotate. Since the tip of the co-rotation preventing blade 24 bites into the ground 1, co-rotation of the stirring means 20 is prevented.

  In addition, although there is no restriction | limiting also in the kind of solidification material, in this embodiment, a slurry-form cementitious suspension is used.

  In the mixing step, the stirring means 20 is inserted into the hole 2 while rotating the stirring blade 22, the excavating blade 23, and the shredded blade 25, and the diameter of the hole 2 is increased by the excavating blade 23 and the like. What is necessary is just to discharge a solidification material. When the slurry-like solidified material is discharged, the solidified material-containing mud soil (soil cement) 4 is mixed with the surrounding ground 1a of the hole 2 excavated when the hole 2 is expanded and the construction generated soil 3 put in the hole 2. It becomes.

  When the solidified material, the ground 1a around the hole 2 and the construction generated soil 3 are sufficiently stirred and mixed, the stirring means 20 is pulled up. Thereafter, when the solidified material-containing mud 4 is cured, a columnar ground improvement body 5 (see FIG. 2C) containing the construction-generated soil 3 is obtained.

  Thus, according to the method for constructing the columnar ground improvement body according to the present embodiment, the construction generated soil 3 can be processed in the field, so that the construction generated soil 3 can be effectively used inexpensively and easily. Can do. Moreover, since a general-purpose base machine for improving the columnar ground can be used, the construction generated soil 3 can be disposed on site without using a special construction machine.

  Moreover, according to the construction method of the columnar ground improvement body according to the present embodiment, the construction generated soil 3 introduced into the hole 2 with the hole wall (ground mountain) exposed is solidified with the surrounding ground 1 a of the hole 2. Thus, the outer diameter of the columnar ground improvement body 5 is larger than the diameter of the hole 2 (the outer diameter of the columnar body).

  When the hole 2 is formed while compressing the ground 1 with the columnar body 10 as in the present embodiment, the amount of soil discharged when forming the hole 2 is reduced. Therefore, when the hole 2 is formed by auger excavation or the like ( It is possible to increase the input amount (disposal amount) of the construction generated soil 3 than when the ground 1 is not compressed. Moreover, if the ground 1 is compressed (consolidated) to form the hole 2, the hole wall of the hole 2 becomes self-supporting even in soft ground such as alluvium and landfill. It is possible to suppress the decrease, and as a result, it is possible to increase the input amount (disposal amount) of the construction generated soil 3.

  Furthermore, when the pulling process is performed with the tip of the cylindrical body 11 opened as in the present embodiment, it is possible to suppress a decrease in the cavity volume at the bottom of the hole 2.

  In addition, in this embodiment, although the case where the stirring means 20 was inserted to the depth equivalent to the depth of the hole 2 was illustrated, the insertion depth (length of the columnar ground improvement body 5) of the stirring means 20 is restrict | limited. is not. Although not shown, the stirring means 20 may be inserted to a position deeper than the bottom surface of the hole 2 to construct a columnar ground improvement body that is longer than the depth of the hole 2.

DESCRIPTION OF SYMBOLS 1 Ground 1a Peripheral ground 2 Hole 3 Construction generated soil 4 Solidification material containing mud 5 Columnar ground improvement body 10 Columnar body 20 Stirring means

Claims (2)

An insertion step of inserting the columnar body into the ground;
A pulling step of pulling up the columnar body from the ground;
A generated soil injection step of introducing construction generated soil into the holes left in the traces of lifting the columnar body,
A mixing step of inserting a stirring means capable of discharging the solidified material into the hole, and mixing the solidified material discharged from the stirring means with the ground around the hole and the construction generated soil. Construction method of columnar ground improvement body. Configure the columnar body using a cylinder,
Performing the insertion step with the end of the cylinder closed;
The method for constructing a columnar ground improvement body according to claim 1, wherein the pulling step is performed in a state in which a tip of the cylindrical body is opened.

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