JP6640820B2 - Improved soil compounding test method for auxiliary water construction at the time of intrusion, and earth removal type deep mixing treatment method - Google Patents

Description

  The present invention relates to an improved soil composition test method for construction of auxiliary water at the time of intrusion, and an earth removal type deep mixing treatment method.

2. Description of the Related Art Conventionally, in a ground improvement method in an urban area, there are many cases in which construction is performed in close proximity, and a displacement-reduction-type method in which displacement of the surrounding ground is suppressed has been demanded. There is known an earth removal type deep mixing treatment method using a treatment apparatus having a method.
Patent Document 1 discloses that, when a rotary shaft having two shafts is penetrated, an amount of soil corresponding to the supply amount of the solidified material is positively discharged, and then the solidified material is supplied to the ground that has penetrated when the rotary shaft is pulled out. This is a displacement-reduced ground improvement method that prevents the ground from being expanded due to the supply of the solidified material by stirring and mixing, thereby avoiding displacement of the surrounding ground. In this case, since the solidified material is not supplied at the time of intrusion, the solidified material is not mixed and discharged from the original ground.

  In addition, as a ground improvement method that streamlines construction efficiency instead of a displacement reduction method, for example, a three-axis deep mixing having a stirring shaft at a tip end and a three-axis rotation axis arranged in parallel as shown in Patent Document 2 There is also known a three-axis type deep mixing treatment method using a treatment device.

  Furthermore, in recent years, there has been a case in which a two-axis ground improvement method that enables large-diameter improvement in which a large-diameter stirring blade has a large improvement area has been implemented, and in this case, there is an advantage that construction cost can be reduced. However, when performing penetration construction with a large diameter stirring blade, the penetration resistance is increased, so that the penetration speed is reduced and the construction efficiency tends to be reduced. Therefore, at the time of penetration, for example, by discharging water from the lower discharge port to promote fluidization, the penetration resistance is reduced and the construction speed is secured, and at the time of drawing, the slurry is discharged from the upper discharge port and mixed by stirring. Improvements are also being made at the site.

Japanese Patent No. 3094266 Japanese Patent No. 4418305

  However, in the case of construction that promotes fluidization by discharging water to the ground at the time of intrusion as described above, the compounding test of slurry is to be a compounding test that collects a sample from the ground and mixes the slurry Therefore, the method does not consider auxiliary water to promote fluidization at the time of intrusion. Therefore, it is an uncertain management method of confirming that the strength is secured by the safety factor by check boring after construction, and there is a problem that accurate strength in ground improvement can not be secured, and there is room for improvement in that respect. there were.

  The present invention has been made in view of the above-described problems, and can perform an improved soil mixing process in which the amount of auxiliary water to be discharged to the ground is accurately controlled, and can grasp the exact strength in ground improvement. It is an object of the present invention to provide an improved soil mixing test method for the construction of auxiliary water at the time of intrusion and an earth removal type deep mixing treatment method.

  In order to achieve the above object, an improved soil compounding test method for intrusion auxiliary water construction according to the present invention comprises: A mixing test method, in which primary agitation for mixing a specified amount of sample soil with an amount of auxiliary water discharged toward the ground at the time of penetration of a rotating rod having a stirring blade by the earth removal type deep mixing machine is performed. Performing a step of preparing a specified amount of water content sample soil, and a step of preparing an improved soil sample by performing secondary stirring to mix a hardening material into the specified amount of water content sample soil. Features.

  The improved soil composition test method for penetration auxiliary water construction according to the present invention is an improved soil composition test method for penetration auxiliary water construction for testing the composition of improved soil constructed by an earth removal type deep mixing machine. For a specified amount of sample soil, the water-cement ratio is calculated from the auxiliary water amount discharged toward the ground when the rotating rod having the stirring blades is penetrated by the earth discharging type deep mixing machine and the prescribed water amount. A step of evaluating the revised corrected water cement ratio, and a step of preparing an improved soil specimen by mixing and stirring the hardening material having the corrected water cement ratio with the specified amount of the sample soil. And

  Further, the earth removal type deep mixing treatment method for the intrusion auxiliary water construction according to the present invention is an earth removal type deep mixing treatment method using the test result obtained by the improved soil composition test method described above, Analyzing the improved soil specimen prepared by the soil mixing test method, and setting an auxiliary water amount at the time of penetration of the rotary rod of the earth removal type deep mixing machine based on an analysis result of the improved soil specimen. And a step of discharging water of the auxiliary water amount set from a discharge port provided in the stirring blade toward the ground, and penetrating while controlling the auxiliary water amount for each excavation depth, I have.

According to the first aspect of the present invention, primary stirring is performed to mix a specified amount of sample soil with the amount of auxiliary water at the time of intrusion, thereby creating a specified amount of water content sample soil, and hardening to the specified amount of water content sample soil. An improved soil specimen is created by performing secondary mixing to mix the materials, and based on the analysis results of the analysis of the created improved soil specimen, assistance is provided for the penetration of the agitating blade of the earth removal type deep mixing processor. The amount of water can be set. In addition, it is possible to perform a construction in which water is discharged from the discharge port provided in the stirring blade toward the ground and the amount of auxiliary water for promoting fluidization is controlled at each excavation depth to penetrate.
As described above, according to the present invention, it is possible to manage by performing a mixing test reflecting changes in soil properties (increase in water content, decrease in soil particles) due to auxiliary water in advance. In particular, in the case of the deep mixing treatment of the earth removal type and the displacement reduction type as in the present invention, the mixed soil having a high water content is discharged because auxiliary water is discharged when the rotating rod penetrates, but the discharged soil is discharged. Since the amount of auxiliary water is controlled to a suitable amount with high accuracy, displacement of the surrounding ground at the time of ground improvement can be suppressed to be small.

According to the second aspect of the present invention, the test can be performed with the properties of the sample soil being the properties at the site. For the hardening material to be mixed, the amount of auxiliary water at the time of intrusion is added to the blending water for the prescribed blending, and the amount of water cement is newly corrected in consideration of the amount of soil removal to calculate. An improved soil specimen was prepared by mixing the hardened material blended with this modified water cement amount with the sample soil, and the agitation of the earth removal type deep mixing machine was performed based on the analysis result of analyzing the created improved soil specimen. Auxiliary water volume at the time of wing penetration can be set.
As described above, in the present invention, it is possible to manage by performing a blending test reflecting changes in soil properties (increase in water, decrease in soil particles) due to auxiliary water in advance. In particular, in the case of the deep mixing process of the earth removal type and the displacement reduction type as in the present invention, the mixed soil having a high water content is discharged to discharge the auxiliary water when the rotating rod penetrates, but the discharge is performed. Since the amount of auxiliary water is controlled to a suitable amount with high accuracy, displacement of the surrounding ground at the time of ground improvement can be suppressed to be small.

  In addition, the method of preparing the improved soil specimen can be based on a conventionally defined preparation method (JGS0821-2009, "Method of preparing a specimen without compaction of stabilized soil"). The test results can be compared and verified, and there is reproducibility, so that the test results can be guaranteed.

  Further, in the earth removal type deep mixing method for construction of auxiliary water at the time of intrusion according to the present invention, the rotating rod is provided in two axes, and the stirring blade has a stirring diameter of 1600 mm or more.

  In the present invention, by controlling the auxiliary water amount based on the result obtained by the improved soil composition test method when the rotating rod penetrates as described above, the displacement of the surrounding ground at the time of ground improvement can be suppressed small, The formula is suitable for a displacement reduction type deep mixing process. Therefore, an earth removal type biaxial deep mixing method using an earth removal type biaxial deep mixing apparatus having a large diameter stirring blade having a stirring diameter of 1600 mm with a biaxial rotating rod can be effectively adopted.

  According to the improved soil mixing test method for the auxiliary water construction at the time of intrusion of the present invention, and the earth removal type deep mixing processing method, it is possible to perform the improved soil mixing processing by accurately controlling the amount of auxiliary water discharged to the ground, Accurate strength in ground improvement can be grasped.

It is a flowchart which shows the working process of the improved soil composition test method by the 1st Embodiment of this invention. (A)-(f) is a figure which shows the process of the earth removal type deep mixing treatment method. It is a flow figure showing an operation process of an improved soil composition test method by a 2nd embodiment of the present invention.

  Hereinafter, an improved soil compounding test method and an earth removal type deep mixing method according to an embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)
As shown in FIG. 1, the first improved soil compounding test method for the construction of auxiliary water at the time of intrusion according to the present embodiment is a method of testing the mixing of the improved soil to be applied by an earth removal type deep mixing machine 1 (see FIG. 2). Is what you do. Then, the first earth removal type deep mixing processing method of the present embodiment uses the earth removal type deep mixing machine using the test result (mixing of the improved soil) obtained by the first improved soil mixing test method described above. 1 is a construction method of performing a deep mixing process.

  Here, as shown in FIG. 2, the earth removal type deep mixing apparatus 1 includes two-axis rotating rods 11, 11 provided with stirring blades 12 at the tip and arranged in parallel, and these two-axis rotating rods 11. , 11 and a solidified material discharge port 14 for ejecting the solidified material to the ground G from the tip of the rotating rods 11, 11.

  Each of the rotating rods 11 has a digging wing 15 at a tip end thereof, and is independently driven by a dedicated driving motor 16. The rotating direction of the rotating rods 11 is set to a direction in which the rotating rods 11 and 11 are rotated to discharge the soil when being pulled out. At the time of pulling out, the excavated soil is collected in the center of the biaxial rotary rods 11 and discharged.

  As shown in FIG. 2, the stirring blades 12 are provided in a plurality of stages (four stages in the illustrated example) on the tip side of the biaxial rotating rods 11, 11. The stirring diameter of the stirring blade 12 provided on each rotating rod 11 can be, for example, 1600 mm.

  The solidified material discharge port 14 is provided in the vicinity of the stirring blade 12 of each of the rotating rods 11, 11. A flow path (not shown) is provided inside the rotary rod 11 throughout the axial direction, and the solidified material supplied to the upper end of the flow path flows to the solidified material discharge port 14. ing. Specifically, it is basically that the solidified material is discharged from the lower solidified material discharge port 14 at the time of processing the tip of the improved portion when the rod penetrates, and the solidified material is discharged from the upper solidified material discharge port 14 at the time of drawing. ing. In the case of the biaxial rotating rods 11, 11 as in the present embodiment, the lower and upper solidified material discharge ports 14 are switched and used.

Next, the first improved soil compounding test method for the auxiliary water construction at the time of intrusion and the first earth removal type deep mixing treatment method will be specifically described based on FIG.
First, in step S1, a prescribed amount of sample soil is mixed with a predetermined amount of auxiliary water discharged toward the ground G when the rotating rod 11 (see FIG. 2) penetrates. Thereafter, the sample soil mixed in step S1 and a predetermined amount of auxiliary water are subjected to primary stirring for 10 minutes (step S2), and a specified amount of water content sample soil is created (step S3).
In addition, the time required for the primary stirring at this time is generally about 10 minutes as defined in JGS0821-2009.

Next, in step S4, a hardening material is mixed with the specified amount of water content sample soil created in step S3. Thereafter, secondary mixing is performed on the mixed specified amount of water content sample soil and the hardened material for 10 minutes (step S5) to prepare an improved soil specimen (step S6).
In addition, the time required for the secondary stirring at this time is generally about 10 minutes as defined in JGS0821-2009 of the Japanese Geotechnical Society.
Steps S1 to S6 up to this point are the work flow according to the first improved soil composition test method.

  Next, in the first earth removal type deep mixing treatment method, first, in step S7, a strength test is performed on the improved soil specimen prepared by the above-described first improved soil composition test method to analyze the composition. Specifically, a strength test is performed by changing the composition of the improved soil specimen prepared in step S7, and a combination of the auxiliary water amount and the composition is selected.

  Then, in step S8, the auxiliary water amount at the time of the penetration construction of the rotating rod 11 of the earth removal type deep mixing machine 1 shown in FIG. 2 is set based on the analysis result of the improved soil specimen. Next, at the time of construction described later, an auxiliary water amount (the auxiliary water amount set in step S8) for discharging water toward the ground G from the solidified material discharge port 14 provided in the stirring blade 12 to promote fluidization is excavated. It is constructed by penetrating while controlling for each depth.

As a concrete construction, first, as shown in FIGS. 2A and 2B, after positioning the earth removal type deep mixing machine 1 at a predetermined construction position, the biaxial rotating rods 11, 11 are moved. Rotate each to penetrate the ground G. At this time, the amount of rotation of the rotating rods 11 is appropriately controlled in consideration of the penetration speed, and the soil is discharged by the respective spirals 13. At this time, the amount of auxiliary water (the amount of auxiliary water set in step S8) for discharging water from the solidified material discharge port 14 provided in the stirring blade 12 toward the ground G and promoting fluidization is controlled for each excavation depth. While penetrating.
Then, as shown in FIG. 2 (c), when the tips (digging wings 15) of the rotating rods 11, 11 reach a predetermined improved lower end depth, the penetration is stopped.

  Next, as shown in FIGS. 2D and 2E, the rotating rods 11 are pulled out halfway in the improved area P. At this time, each of the rotating rods 11 raises the rotating rods 11, 11 and the stirring blades 12 while discharging the solidified material from the solidified material discharge port 14 while maintaining the rotation at the time of penetration, thereby improving the area P per span. Is completed (see FIG. 2 (f)).

  Then, after the improved body is constructed to the desired depth, as shown in FIG. 2 (f), the entire apparatus of the earth removal type deep mixing machine 1 is pulled up to the ground and moved to the next construction position, and the above-described improvement is performed. Based on the amount of auxiliary water obtained by the soil composition test method, the steps of FIGS. 2A to 2F are similarly repeated to construct another improved body.

Next, the effects of the improved soil compounding test method and the earth removal type deep mixing treatment method for the above-described intrusion auxiliary water construction will be described in detail with reference to the drawings.
In the first embodiment, as shown in FIG. 1, it is possible to manage by performing a compounding test reflecting changes in soil properties (increase in water content, decrease in soil particles) due to auxiliary water in advance. In particular, in the case of the deep mixing processing of the earth removal type and the displacement reduction type as in the present embodiment, the mixed soil having a high water content is discharged because auxiliary water is discharged when the rotating rod 11 penetrates. Since the auxiliary water amount of the discharged water is accurately controlled to a suitable amount, the displacement of the surrounding ground at the time of ground improvement can be suppressed to be small.

  Further, in the first embodiment, as described above, by controlling the auxiliary water amount based on the result obtained by the first improved soil composition test method when the rotating rod 11 penetrates, the surrounding ground at the time of ground improvement is managed. The displacement can be suppressed to a small value, which is suitable for a deep-mixing process of an earth removal type and a displacement reduction type. Therefore, an earth removal type biaxial deep mixing method using an earth removal type biaxial deep mixing apparatus 1 having a large diameter stirring blade 12 having a stirring diameter of 1600 mm with the biaxial rotating rods 11 and 11 is effectively adopted. can do.

  As described above, in the improved soil mixing test method for the auxiliary water construction at the time of intrusion according to the present embodiment, and in the earth removal type deep mixing processing method, the improved soil mixing processing in which the amount of auxiliary water discharged to the ground is accurately controlled is performed. It is possible to grasp the exact strength in ground improvement.

(Second embodiment)
Next, a description will be given of a second improved soil compounding test method and a second earth removal type deep mixing treatment method for the construction of auxiliary water at the time of intrusion according to the second embodiment with reference to a flowchart shown in FIG.
Here, the earth removal type deep mixing machine 1 (see FIG. 2) for testing the composition of the improved soil by the test method in the second embodiment is the same as the first embodiment described above. The second embodiment will be described with reference to FIG. 2 used in the first embodiment.

First, in step S10, a specified amount of sample soil is created.
On the other hand, the penetration speed of the rotating rod 11 (see FIG. 2) and a predetermined amount of auxiliary water discharged toward the ground G are set (step S11). Thereafter, the amount of auxiliary water to be supplied to the target soil stirred at the penetration speed set in step S11 is calculated (step S12). Specifically, the amount of auxiliary water per volume of the soil to be improved is calculated. Then, in step S13, the earth removal rate is set from the supplied auxiliary water amount to calculate the earth removal amount. Further, the amount of added cement and the amount of compounded water are calculated from the prescribed mixture (water-cement ratio) with respect to the amount of soil to be improved after the soil is discharged (step S14).

Thereafter, in step S15, a corrected water cement ratio (corrected water cement ratio) is calculated from the calculated cement addition amount, blended water amount and auxiliary water amount. A hardening material having a corrected water-cement ratio is mixed with the specified amount of sample soil prepared in step S10 (step S16). Thereafter, the specified amount of the sample soil mixed in step S10 and the hardened material having the modified water-cement ratio are stirred for 10 minutes (step S17), and an improved soil specimen is prepared (step S18).
In addition, the time required for the stirring at this time is generally about 10 minutes as defined in JGS0821-2009.
Steps S10 to S18 so far are the work flow according to the second improved soil compounding test method.

  Next, in the earth removal type deep mixing method, first, in step S19, a strength test is performed on the improved soil specimen prepared by the above-described second improved soil composition test method to analyze the composition. Specifically, a strength test is performed by changing the composition of the improved soil specimen prepared in step S19, and a combination of the auxiliary water amount and the composition is selected.

After that, in step S20, the auxiliary water amount at the time of the penetration construction of the rotating rod 11 of the earth removal type deep mixing machine 1 shown in FIG. 2 is set based on the analysis result of the improved soil specimen. Next, at the time of construction described below, an auxiliary water amount (the auxiliary water amount set in step S20) for discharging water toward the ground G from the solidified material discharge port 14 provided in the stirring blade 12 to promote fluidization is excavated. It is constructed by penetrating while controlling for each depth.
The specific construction is the same as that of the first embodiment described above, and a detailed description is omitted here.

In the second embodiment, the test can be performed with the properties of the sample soil being the properties of the site. For the hardening material to be mixed, the amount of auxiliary water at the time of intrusion is added to the blending water for the prescribed blending, and the amount of water cement is newly corrected in consideration of the amount of soil removal to calculate. An improved soil specimen is prepared by mixing the hardened material blended with the modified water cement amount with the sample soil, and based on an analysis result obtained by analyzing the created improved soil specimen, the soil removal type deep mixing machine 1 is used. It is possible to set the amount of auxiliary water at the time of penetrating construction of the stirring blade 14.
As described above, in the present embodiment, it is possible to manage by performing a combination test reflecting changes in soil properties (increase in water content, decrease in soil particles) due to auxiliary water in advance. In particular, in the present embodiment, as described above, the auxiliary soil is discharged when the rotating rod 11 penetrates, so that the mixed soil having a high water content is discharged, but the auxiliary water amount of the discharged water is set to a suitable amount. Since it is managed with high accuracy, the displacement of the surrounding ground at the time of ground improvement can be suppressed to a small value.

  In addition, the method of preparing the improved soil specimen can be based on a conventionally defined preparation method (JGS0821-2009, "Method of preparing a specimen without compaction of stabilized soil"). The test results can be compared and verified, and there is reproducibility, so that the test results can be guaranteed.

As mentioned above, although the embodiment of the improved soil composition test method for the auxiliary water construction at the time of intrusion according to the present invention and the earth removal type deep mixing treatment method has been described, the present invention is not limited to the above embodiment, It can be changed as appropriate without departing from the spirit thereof.
For example, although the stirring time by the primary stirring and the secondary stirring in the first embodiment and the stirring time in the second embodiment are each set to about 10 minutes, the stirring time is not necessarily limited to this range. It will not be done.

  In the present embodiment, a rotating rod 11 is provided as a biaxial shaft and the stirring blade 12 has a large diameter with a stirring diameter of 1600 mm or more. The stirring diameter is not limited to the above, and a stirring diameter of, for example, 1000 mm to 1300 mm may be used. For example, in the ground where the resistance at the time of intrusion is assumed to be large, it is also possible to adopt the above-mentioned one having a stirring diameter of not more than 1600 mm.

  In addition, it is possible to appropriately replace the components in the above-described embodiment with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Earth removal type deep mixing apparatus 11 Rotating rod 12 Stirrer blade 13 Spiral 14 Solidification material discharge port 15 Excavation wing G Ground P Improvement area

Claims (4)

An improved soil composition test method for intrusion auxiliary water construction for testing the composition of improved soil constructed by an earth removal type deep mixing machine,
A primary stirring is performed to mix a specified amount of sample soil and an auxiliary amount of water discharged toward the ground when the rotating rod having a stirring blade is penetrated by the earth removal type deep mixing processor, and a specified amount of water content is performed. A step of preparing a sample soil,
A step of creating an improved soil specimen by performing secondary stirring to mix the hardening material into the specified amount of water content sample soil,
An improved soil composition test method for construction of auxiliary water at the time of intrusion, characterized by having: An improved soil composition test method for intrusion auxiliary water construction for testing the composition of improved soil constructed by an earth removal type deep mixing machine,
For a specified amount of sample soil, the water-cement ratio was reviewed based on the auxiliary water amount discharged toward the ground when the rotating rod having a stirring blade was penetrated by the earth discharging type deep mixing machine and the prescribed water content and the prescribed water content. Evaluating the modified water cement ratio;
A step of preparing an improved soil specimen by performing stirring to mix the hardening material having the corrected water cement ratio with the specified amount of sample soil,
An improved soil composition test method for construction of auxiliary water at the time of intrusion, characterized by having: An earth removal type deep mixing treatment method using a test result obtained by an improved soil composition test method for construction of an auxiliary water at the time of intrusion according to claim 1 or 2,
Analyzing the improved soil specimen prepared by the improved soil composition test method,
A step of setting an auxiliary water amount at the time of penetration of the rotating rod of the earth removal type deep mixing processor based on an analysis result of the improved soil specimen,
Discharging the water of the auxiliary water amount set from the discharge port provided in the stirring blade toward the ground, and penetrating while controlling the auxiliary water amount for each excavation depth,
An earth removal type deep mixing method for construction of auxiliary water at the time of intrusion, characterized by having: The rotating rod is provided on two axes,
The method according to claim 3, wherein the stirring blade has a stirring diameter of 1600 mm or more.

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