JP4042010B2 - Ground improvement body construction method and continuous wall construction method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a ground improvement body construction method and a continuous wall construction method, and more specifically, in a pulling process using a stirring rod, cement mixed mud and in-situ ground soil are mixed and replaced with a loose borehole. The soil cement pillar is created as described above.
[0002]
[Prior art]
In the so-called deep mixing treatment method and soil-sentment wall method, a process in which an agitating blade that is provided with an agitating blade projecting outward from the shaft member is inserted into the target ground while rotating, or a process in which the stirring rod is pulled up after being penetrated. Cement milk is supplied to the soil, and the soil soil pillar is created by stirring and mixing with the original ground soil.
[0003]
[Problems to be solved by the invention]
However, in the construction method of the soil cement column that supplies cement milk when the stirring rod is inserted or when the stirring rod is pulled up, because the cement milk is highly fluid, in principle, the same amount of mud soil as the injected cement milk is grounded. To be discharged.
[0004]
In recent years, from the viewpoint of location, waste disposal of this cement-mixed waste mud has become a major social problem.
[0005]
On the other hand, kneadability or stirring and mixing properties between cement milk and local soil are not sufficient, and it is difficult to create a soil cement column with high strength and homogeneity.
[0006]
Accordingly, a main problem of the present invention is to create a soil cement column having a very small amount of cement-containing waste mud and excellent kneadability and having a uniform strength, or a continuous wall in which these are continuous.
[0007]
[Means for Solving the Problems]
[0008]
The invention according to claim 1 of the present invention that has solved the above problems has a water injection port at the tip, and a cement mixed mud discharge port is provided at the tip of the base side from the water injection port, at least from the discharge port. Below, using a stirring rod having stirring blades that are inclined so as to act in a direction to push down the stirring and mixing treated soil when rotating at the time of pulling up ,
After piercing the target ground to a predetermined depth, while pouring water from the water inlet, loosening the ground with the stirring rod,
In the process of pulling up the stirring rod while rotating, the cement mixed mud having a slump value of 6 cm or more is discharged from the discharge port, and the corresponding improvement target area is preferentially filled and replaced with the cement mixed mud, The in-situ ground soil is taken in as much as insufficient to close-pack the area to be improved, and the in-situ ground soil and cement-mixed mud are stirred and mixed by the stirring blades,
In this lifting process, cement is added to the discharged mud discharged to the ground to produce cement mixed mud having a slump value of 6 cm or more, and the produced cement mixed mud is supplied as the cement mixed mud discharged from the discharge port. ,
It is a ground improvement body construction method characterized by creating soil cement pillars by this lifting process.
[0009]
The invention according to claim 2, after piercing the target ground to a predetermined depth, while pouring water from the water inlet, loosening the ground with the stirring rod,
The stirring rod is once pulled up to a level at which the water injection port is substantially located at the discharge port. From this state, the cement mixing mud having a slump value of 6 cm or more is discharged from the water injection port to the original deepest position. While preferentially filling and replacing the cement mixed mud discharged in the improvement target area, the ground soil in the original position is taken in as much as it is insufficient to densely fill the improvement target area. Cement mixed mud and agitated and mixed with the agitating blade,
Next, from the deepest position or from the level, performing a process of pulling up the stirring rod while rotating,
It is the ground improvement body construction method of Claim 1.
[0010]
[0011]
[0012]
Third aspect of the present invention, the discharge port has a more stirring blade also upward, stirring blades of the upward claim 1 is inclined so as to act in a direction to push up the mud at the time of rotation at the pulling or This is a construction method of the ground improvement body described in 2 .
[0013]
The invention according to claim 4 eliminates coarse particles from the discharged mud discharged to the ground side, obtains mud composed of fine particles and water, adds cement to the mud, and mixes the cement It is a ground improvement body construction method of any one of Claims 1-3 which manufactures a mud.
[0014]
According to a fifth aspect of the invention, has a water inlet at the distal end, the discharge port of the cement mixing mud is provided on the tip portion of the base side of the water inlet, lower than at least the discharge opening, during rotation at the pulling the stirred mixture treated soil stirring rod having an inclined stirring blade so as to act in the direction to depress downward, using a multi-axis stirrer mixer juxtaposed with a plurality of parallel in,
After piercing the target ground to a predetermined depth, while pouring water from the water inlet, loosening the ground with the stirring rod,
In the process of pulling up the stirring rod while rotating, the cement mixed mud having a slump value of 6 cm or more is discharged from the discharge port, and the corresponding improvement target area is preferentially filled and replaced with the cement mixed mud, The in-situ ground soil is taken in as much as insufficient to close-pack the area to be improved, and the in-situ ground soil and cement-mixed mud are stirred and mixed by the stirring blades,
In this lifting process, cement is added to the discharged mud discharged to the ground to produce cement mixed mud having a slump value of 6 cm or more, and the produced cement mixed mud is supplied as the cement mixed mud discharged from the discharge port. ,
Through this pulling process, the number of shaft soil cement columns for the number of shafts was created,
This is a continuous wall construction method characterized in that this soil cement column is made continuous to create a continuous wall.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First, an example of a single-shaft stirring rod according to the present invention used in this embodiment will be described with reference to FIGS. The stirring rod 1 has lower stirring blades 4, 4... Having a function of pushing down (pressing) the treated soil having different inclination directions on the shaft member 2, and an upper stirring having a function of pushing up (performing desulfurization / mudging) Each of the blades 5, 5. The excavation stirring blade 3 at the tip is provided with excavation bits 3a, 3a.
[0016]
A water injection port 6L is formed at the distal end portion of the distal end portion, and a discharge port 6U is formed at the base side. The discharge port 6U is formed above the lower stirring blades 4, 4... And below the upper stirring blades 5, 5.
[0017]
Further, the shaft member 2 of the stirring rod 1 in the illustrated example has a double tube structure, although details are not shown.
It is rotated by a rotary drive device 7 including a speed reducer. A double hose 9 for supplying water and cement mixed mud is connected to the shaft member 2 via a swivel joint 8.
[0018]
As shown in FIG. 2, when the shaft member 2 is pulled up and rotated in the direction of rotation, the lower agitating blades 4, 4... The upper stirring blades 5, 5,... Have a function of pushing up the discharged mud (performing thaw / deep mud).
[0019]
Next, the ground improvement body construction method which concerns on this invention using this stirring rod is demonstrated.
<Preparation process>
FIG. 3 shows a preparatory state in which the stirring rod 1 according to the present invention is mounted on a base machine (not shown) and the tip thereof is set toward the target ground.
[0020]
Preferably, in order to reuse the discharged mud discharged to the ground side due to excavation penetration and stirring and mixing, the discharge rod mud sedimentation basin 10 is made to communicate with the portion that becomes the mouth when the stirring rod 1 is drilled and penetrated. At the same time, a cement mixed mud production plant 20 is installed in the vicinity of the sedimentation basin 10.
[0021]
The mud in the sedimentation basin 10 is pumped up by the backhoe BH (may be pumped up by a pump (not shown)) and supplied to the hopper 21 of the manufacturing plant 20. The hopper 21 is separately provided with cement (in the present invention, “cement” includes all materials mainly composed of cement, such as cement mortar, cement clay, cement lime, etc.) G and necessary. Accordingly, water W1 and additive AD (other inorganic materials such as fine particle slag and bentonite, foaming agent, foaming agent, separation preventing agent, water reducing agent, etc.) are supplied at a predetermined blending ratio. The discharged mud and cement G supplied to the hopper 21 are quantitatively supplied to the mixing drum 22 and kneaded. And this kneaded material is supplied into the stirring rod 1 by a pressure pump (a commercially available concrete pump is used) 23 as cement mixed mud. The cement-mixed mud from the pressure feed pump 23 is configured to be discharged from the discharge port 6U through the double pipe hose 9.
[0022]
The sedimentation basin 1 is divided into a first sedimentation basin 10A that communicates with the entrance of the penetration portion and a second sedimentation basin 10C that communicates with the sedimentation basin 10B via a sink weir 10B as shown in the figure. It is preferable that the coarse particles are separated into the second settling basin 10C and supplied to the cement mixed mud production plant 20.
[0023]
<Drilling penetration process>
When this preparation is completed, the process proceeds to the excavation and penetration step of the stirring rod 1. That is, as shown in FIG. 4, excavation auxiliary water such as water W2 is supplied from the water injection port 6L at the tip through a double pipe hose 9, and the agitating rod 1 is rotated and lowered to turn the excavation blade 3 at the tip. The agitating rod 1 is penetrated into the target ground to a predetermined depth while excavating by the above method. Thereby, a column of mud is formed in the improvement target area. In some cases, such as when the target ground is loose, excavation can be performed without using the excavation water W2.
[0024]
Along with this excavation penetration, the discharged mud M overflows from the mouth of the penetration part. The overflowing mud M overflows and settles and separates coarse particles in the settling tank 10. The supernatant mud MW composed of fine particles and water is pumped up by the backhoe BH and supplied to the cement mixed mud production plant 20. In the production plant 20, cement mixed mud is produced by adding cement G or the like to the mud MW from the sedimentation basin 10. This cement-mixed mud is supplied into the double pipe hose 9 by the pressure pump 23 in the subsequent stirring and mixing step.
[0025]
In particular, it is preferable that the cement-mixed mud be kneaded as much as possible by a pumping means such as a pumping pump 23 or a transporting path. In the present invention, the composition in the kneaded product is determined so that the slump value of the kneaded product is 6 cm or more. In particular, it is desirable to determine the slump value of the kneaded material to be 8 cm or more from the viewpoint of the pumpability by the concrete pump 23 and the certainty of replacement in the drilling penetration hole. Since this kneaded material (cement mixed mud) is stirred and mixed with the raw ground soil in the stirring and mixing step described later, it is preferable to determine the cement addition ratio in consideration of the stirring and mixing ratio.
[0026]
<Stirring and mixing step>
When the excavation and penetration of the stirring rod 1 is completed, stirring and mixing are preferably performed as follows. That is, as shown in FIG. 5, the stirring rod 1 is pulled up so that the water injection port 6L is located in the vicinity of the depth position of the discharge port 6U in a state where the stirring rod 1 is penetrated to a predetermined depth.
[0027]
Thereafter, as shown in FIG. 6, the cement mixed mud MG from the cement mixed mud production plant 20 is supplied to the stirring rod 1 in the process of penetrating to the deepest part while rotating the stirring rod 1 in a predetermined direction. The discharged cement mixed mud MG and the original mud are stirred and mixed.
[0028]
Next, when the stirring rod 1 reaches a predetermined deepest portion, as shown in FIG. 7, the cement mixing mud manufacturing plant 20 is in the process of pulling up while rotating the stirring rod 1 in a predetermined direction (the direction opposite to the stirring at the time of penetration). The cement mixed mud MG is discharged from only the discharge port 6U, and the discharged cement mixed mud MG and the ground soil in the original position are mixed by stirring.
[0029]
Also in this pulling up process, the rising of the stirring and mixing treated soil MB2 to the ground is suppressed by the pressing action of the lower stirring blades 4, 4,..., And the discharged mud M above the pressing action region is , 5..., 5. Then, a mixed improved body of the local board and the cement mixed mud MG from the discharge port 6U is created in the remaining improved area. Further, the mud discharged to the settling basin 10 in accordance with the stirring and mixing step is used for manufacturing the cement mixed mud in the cement mixed mud manufacturing plant 20 described above, and the manufactured cement mixed mud is sequentially supplied to the stirring rod 1. . By this stirring and mixing step, a soil cement column is formed over the entire lifting area of the stirring rod 1.
[0030]
In particular, in such a stirring and mixing step, the cement mixed mud MG discharged from the water injection port 6L at the time of penetration and the cement mixed mud MG supplied from the discharge port 6U at the time of pulling up have priority in the corresponding improvement target areas, respectively. Thus, the improved body is created while taking in the ground soil in the original position as much as it is necessary to fill the interior of the area to be improved. Therefore, it is possible to create a soil cement column having a desired blending ratio with respect to the improvement target region.
[0031]
Moreover, since each stirring mixing process soil MB1, MB2 is pushed down by the lower stirring blades 4, 4, ..., the cement mixing mud MG is mixed in the discharged mud M discharged to the ground side by the upper stirring blades 5, 5, ... do not do. Therefore, the discharged mud M discharged to the ground side can be reused in the production of the cement mixed mud MG in the plant 20 described above or in other applications.
[0032]
On the other hand, below, the change of the content of the improvement area | region in the above-mentioned improvement body construction method example is explained in full detail based on FIG.
First, it is assumed that the composition of the ground before excavation penetration of the stirring rod 1 is shown as an initial state in FIG. When the agitation rod 1 is drilled and penetrated while supplying the drilling water W2 to the target ground, the amount of the drilling water W2 supplied, the volume of the agitation rod 1 and the amount by the pushing-up action of the upper stirring blade 5 at the time of excavation penetration The discharged mud M is discharged to the settling basin 10. Instead, the stirring rod 1 and the drilling water W2 are added as the contents of the penetration region.
On the other hand, the discharged mud M generated by the excavation penetration is removed by coarse separation in the sedimentation basin 10 to obtain mud water composed of fine particles and water, and cement is added to the mud water to obtain the cement mixed mud MG. To manufacture. The amount of cement to be added is determined by taking into account the amount of in situ mud taken up during stirring and mixing. Water is added in consideration of the pumpability to the stirring rod 1 as necessary, for example, when the muddy water is low.
When stirring and mixing is performed using the cement-mixed mud MG, the stirring rod 1 is pulled out, and further, the discharged mud M corresponding to the supply amount of the cement-mixed mud MG is discharged to the settling basin 10, while these decreases The amount of cement mixed mud MG corresponding to the minute is added. Therefore, an improved body corresponding to a desired blending ratio is created. In addition, although a small amount of waste mud is finally generated, the cement mixed mud is not mixed with the mud produced by the stirring and mixing due to the pushing-up action of the upper stirring blade 5 and the pushing-down action of the lower stirring blade 4 next time. It can be used for the production of cement-mixed mud MG at the time of construction of the improved body. Therefore, in this construction method, cement mixed mud and mud mixed waste are not generated, and the generated mud can be reused.
[0033]
<Examples of application to deep mixing treatment method>
By the way, as is clear from the above example, the present invention is applied to a soil cement deep layer mixing process or a continuous wall method in addition to a method of individually creating a single soil cement column in a target ground by mechanical stirring and mixing. be able to.
[0034]
For example, when the deep mixing process is performed with two axes, as shown in FIG. 9, two stirring rods 100A and 100B similar to the stirring rod 1 shown in FIG. 1 and the like are connected in a parallel arrangement. Using the biaxial stirring rod 100, an improved body can be formed in the same manner as in the case of the single axis described above. In FIG. 9, 102A, 102B indicate shaft members of the respective rods, 103A, 103B, digging and stirring blades of the respective stirring rods, 104A, 104B, and the lower stirring blades of the respective stirring rods, 105A,. , 105B... Indicate upper stirring blades of the respective stirring rods, 106U and 106L respectively indicate discharge ports and water injection ports, and 107 indicates a biaxial rotation drive device that rotates both the stirring rods 100A and 100B in opposite directions. 110 denotes a biaxial connecting member for connecting the lower portions of both rods. In addition, the top view of improved body B1 constructed | assembled using this stirring rod 100 was shown in FIG.
[0035]
Moreover, when applying this invention to a soil cement continuous wall construction method, the triaxial stirring rod shown in FIG. 11 can be used. That is, a three-axis stirring rod 200 configured by connecting three stirring rods 200A to 200C similar to the stirring rod 1 shown in FIG. In FIG. 11, 202A to 202C indicate shaft members of the respective rods, 203A to 203C indicate excavation stirring blades of the respective stirring rods, 204A to 204C indicate lower stirring blades of the respective stirring rods, and 205A to 205C indicate the respective stirring members. The upper stirring blades of the rod are shown, 206U and 206L show the discharge port and the water injection port, respectively, and 207 shows a three-axis rotation drive device that rotates the adjacent stirring rods 200A, 200B and 200B, 200C in the reverse direction. , 210 indicates a triaxial connecting member that connects the lower portions of the rods.
[0036]
In particular, in the triaxial stirring rod 200 of FIG. 11, the rotation trajectory of the stirring blades 204C and 205C of the stirring rod 200C at the end is smaller than the other stirring blades, and the rotation of the stirring blades of the adjacent central stirring rod 200B is rotated. It is configured so that it does not overlap with the trajectory at one point, and the rotation trajectory of the stirring rod 200A at the other end wraps with the rotation trajectory of the stirring blade of the adjacent central stirring rod 200B. In this case, the shape of the improved body B1 constructed by one creation is as shown in FIG.
[0037]
At the time of construction, one improved body is created in the same manner as in the case of the single shaft described above. By performing such formation in accordance with a so-called continuous method (standard method or one-push method) or a so-called prior drilling method using a single-shaft stirring rod, a completely wrapped soil cement continuous wall 300 as shown in FIG. Can be created.
[0038]
<Others>
(A) In the present invention, all of the stirring blades of the stirring rod can be formed as lower stirring blades.
[0039]
(B) Further, the discharge port for the cement-mixed mud according to the present invention can be provided on the stirring blade in addition to the shaft member as long as it is within the region where the stirring material is pushed down by the lower stirring blade. When the discharge port is provided on the stirring blade, the discharge port is provided on the lower surface of the blade, and the cement-mixed mud can be discharged from the discharge port below the blade through the shaft member and the stirring blade.
[0040]
(C) In the present invention, the cement-mixed mud can be discharged continuously during pulling or penetration, but can also be discharged intermittently.
[0041]
(D) In the stirring rod of the present invention, it is preferable that the volume of the rod portion corresponding to the push-down action region is made larger than that of other portions by increasing the diameter of the shaft member, for example. As a result, the amount of in-situ ground soil during stirring and mixing can be reduced, and an improved body with a desired blending ratio can be created more reliably in the improved region.
[0042]
[0043]
( E ) On the other hand, in the above embodiment, when the upper stirring blades 5, 5... Target the ground having a large resistance when penetrating, as shown in FIG. When the upper stirring blades 5, 5... Are attached to the upper rod 2A and the lower stirring blades 4, 4,... Are attached to the lower rod 2B and rotated as shown in the drawing, the resistance to the ground is small. Become.
Furthermore, for the purpose of reducing the resistance, as shown in FIG. As shown in FIG. 16, it is also possible to have a movable cross-sectional chevron 52 that automatically rotates when rotating about a central axis 52a.
[0044]
【The invention's effect】
As described above, according to the present invention, it is possible to construct a soil cement column having a very small amount of cement-mixed waste mud and excellent in kneadability and having a uniform strength or a continuous wall in which these are continuous.
[0045]
That is, the cement-based material is added to the discharged mud discharged to the ground, and this is returned to the penetration hole and discharged from the discharge port, so the amount of cement-containing mud is extremely small.
[0046]
Since the cement-mixed mud discharged from the discharge port is forcibly stirred and mixed by the stirring blade, it has extremely excellent kneadability. Therefore, a homogeneous soil cement pillar can be created.
[0047]
In this case, in particular, by setting the slump value of the pressed stirring blade and / or the slump value of the rich blended cement-mixed mud to be 8 cm or more, an improved body always replaced can be formed below the discharge port.
[Brief description of the drawings]
FIG. 1 is a front view showing a stirring rod according to the present invention.
FIG. 2 is a longitudinal sectional view thereof.
FIG. 3 is a schematic view showing a preparation step in the improved body construction method according to the present invention.
FIG. 4 is a schematic view showing an excavation and penetration step in the improved body construction method according to the present invention.
FIG. 5 is a schematic view showing a preparation stage of a stirring and mixing step in the improved body construction method according to the present invention.
FIG. 6 is a schematic view showing an initial stage of a stirring and mixing step in the improved body construction method according to the present invention.
FIG. 7 is a schematic view showing the latter stage of the stirring and mixing step in the improved body construction method according to the present invention.
FIG. 8 is an explanatory view showing a change in contents of a stirring rod penetration region in the improved body construction method according to the present invention.
FIG. 9 is a front view showing a biaxial stirring rod according to the present invention.
FIG. 10 is a plan view showing an improved body formed using the biaxial stirring rod according to the present invention.
FIG. 11 is a front view showing a triaxial stirring rod according to the present invention.
FIG. 12 is a plan view showing an improved body obtained by one creation using the triaxial stirring rod according to the present invention.
FIG. 13 is a plan view showing a soil cement wall formed using a triaxial stirring rod according to the present invention.
FIG. 14 is an explanatory diagram showing another embodiment of the present invention.
FIG. 15 is an explanatory view showing another stirring blade according to the present invention.
FIG. 16 is an explanatory diagram showing another stirring blade according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Stirring rod, 2 ... Shaft member, 3 ... Excavation stirring blade, 4 ... Lower stirring blade, 5 ... Upper stirring blade, 6U ... Discharge port, 6L ... Water injection port, 7 ... Rotation drive device, 8 ... Swivel joint.

Claims (5)

There is a water injection port at the tip, and a cement mixed mud discharge port is provided at the tip of the base side from this water injection port, at least below the discharge port, and at the time of rotation at the time of lifting, the stirring and mixing treated soil is downward Using a stirring rod having stirring blades inclined so as to act in the pushing down direction ,
After piercing the target ground to a predetermined depth, while pouring water from the water inlet, loosening the ground with the stirring rod,
In the process of pulling up the stirring rod while rotating, the cement mixed mud having a slump value of 6 cm or more is discharged from the discharge port, and the corresponding improvement target area is preferentially filled and replaced with the cement mixed mud, The in-situ ground soil is taken in as much as insufficient to close-pack the area to be improved, and the in-situ ground soil and cement-mixed mud are stirred and mixed by the stirring blades,
In this lifting process, cement is added to the discharged mud discharged to the ground to produce cement mixed mud having a slump value of 6 cm or more, and the produced cement mixed mud is supplied as the cement mixed mud discharged from the discharge port. ,
Ground improvement body construction method characterized by creating soil cement pillars by this lifting process. After injecting water into the target ground up to a predetermined depth, while pouring water from the water inlet, loosening the ground with the stirring rod,
The stirring rod is once pulled up to a level at which the water injection port is substantially located at the discharge port. From this state, the cement mixing mud having a slump value of 6 cm or more is discharged from the water injection port to the original deepest position. While preferentially filling and replacing the cement mixed mud discharged in the improvement target area, the ground soil in the original position is taken in as much as it is insufficient to densely fill the improvement target area. Cement mixed mud and agitated and mixed with the agitating blade,
Next, from the deepest position or from the level, performing a process of pulling up the stirring rod while rotating,
The ground improvement body construction method of Claim 1. The ground improvement body according to claim 1 or 2 , further comprising a stirring blade above the discharge port, and the upper stirring blade is inclined so as to act in a direction of pushing up the mud during rotation when being pulled up. Construction method. 1 to remove the coarse particles from the discharged mud discharged to the ground side, obtain a mud composed of fine particles and water, and add cement to the mud to produce the cement mixed mud. 3. The ground improvement body construction method according to any one of 3 above. There is a water injection port at the tip, and a cement mixed mud discharge port is provided at the tip of the base side from this water injection port, at least below the discharge port, and at the time of rotation at the time of lifting, the stirring and mixing treated soil is downward stirring rod having stirring blades which are inclined so as to act in the direction to depress the, using multi-axis stirrer mixer juxtaposed with a plurality of parallel,
After injecting water into the target ground up to a predetermined depth, while irrigating water from the water inlet, loosening the ground with the stirring rod,
In the process of pulling up the stirring rod while rotating, the cement mixed mud having a slump value of 6 cm or more is discharged from the discharge port, and the corresponding improvement target area is preferentially filled and replaced with the cement mixed mud, The in-situ ground soil is taken in as much as it is insufficient to densely fill the area to be improved, and the in-situ ground soil and cement-mixed mud are stirred and mixed by the stirring blades,
In this lifting process, cement is added to the discharged mud discharged to the ground to produce cement mixed mud with a slump value of 6 cm or more, and the produced cement mixed mud is supplied as the cement mixed mud discharged from the discharge port. ,
Through this pulling process, the number of continuous soil cement columns for the number of shafts was created,
A continuous wall construction method characterized in that this soil cement column is made continuous to create a continuous wall.

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