Soil discharging lid of columnar ground improvement device and columnar ground improvement method

Abstract

To provide a soil discharging lid of a columnar ground improvement device having both a soil discharging function of excavated soil and improved soil, and a lid function of suppressing raising of improved soil, and a columnar ground improvement method using the same.SOLUTION: A soil discharging lid 1 of a columnar ground improvement device includes a body cylinder 10 which can be externally fit to an excavation rod A3, and a spiral blade 20 which is externally provided on the body cylinder 10, wherein the lower part of the body cylinder 10 is configured to be attachable / detachable to / from the upper part of an excavation blade A4. A columnar ground improvement method includes a drilling step S1 of rotating and pressing-in the excavation blade A4, and penetrating the excavation blade A4 into the ground, a soil discharging step S2 of discharging excavated soil C above a penetration depth of the excavation blade A4, and an improvement step S3 of discharging a solidification material D from the excavation blade A4 while rotating and pressing-in the excavation blade A4 below the penetration depth of the excavation blade A4, stirring and mixing the solidification material D and the excavated soil C and forming improved soil E1, and constructing a columnar improved body E by the improved soil E1. In the soil discharging step S2, the excavation blade A4 is pulled up, and thereby the excavated soil C is pushed up by the spiral blade 20 of the soil discharging lid 1 mounted on the excavation blade A4, and the excavated soil C is discharged.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a soil discharge cover for a columnar ground improvement device and a columnar ground improvement method, and in particular to a soil discharge cover for a columnar ground improvement device that combines the function of discharging excavated soil and improved soil with the function of a cover for suppressing the heaping of the improved soil, and a columnar ground improvement method using the same. [Background technology]

[0002] When the ground on which a house, commercial building, or other such structure sits is weak, ground improvement work is carried out to improve the strength of the ground by adding artificial treatments to it. Patent Documents 1 to 3 disclose a columnar ground improvement method as one of the methods used in ground improvement works. The columnar ground improvement method aims to increase the allowable bearing capacity of soft ground by rotating a rod with an excavation wing attached to the lower end into the ground while discharging solidification material (cement slurry) from the excavation wing, and stirring and mixing the excavated soil and solidification material to build a cylindrical improvement body. The columnar ground improvement method has several advantages over the pile method, such as being cheaper to construct, being able to perform construction with less vibration and noise, and being easy to construct on small sites, and is therefore widely used as a ground improvement method for the sites of small and medium-sized structures. In the columnar ground improvement method, the volume of the improved soil increases by mixing the excavated soil and the solidification material, and by the amount of solidification material injected and the amount of soil loosened by mixing. For this reason, the excavation is performed without mixing the solidification material, with the depth of the excavated soil being determined by adding the increase in the volume of the solidification material and excavated soil to the foundation bottom level as the dry excavation section. Patent documents 1 and 2 disclose a technique in which, after excavating an air excavation section, a columnar improvement body is constructed below the air excavation section without removing the excavated soil from the air excavation section, and the excavated soil is removed after construction. Patent Document 3 discloses a technique in which a soil discharge blade is attached below the mixing blade of a columnar ground improvement device to discharge soil, and after the soil is discharged, the soil discharge blade is removed and a columnar improved body is constructed with an excavation blade. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-8454 [Patent Document 2] JP 2006-28854 A [Patent Document 3] Japanese Patent Application Publication No. 08-158357 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional techniques have the following problems. <1> In the technology of Patent Documents 1 and 2, which constructs columnar improved bodies without discharging soil from the dry excavation, the increase in the volume of the improved soil is estimated, and if the increase in volume is greater than the estimate, improved soil mixed with solidification material will be mixed in with the excavated soil in the dry excavation. In this case, it becomes necessary to treat the entire amount of soil discharged from the dry excavation as industrial waste, which increases disposal costs. <2> The technology of attaching soil discharge blades below the mixing blades in Patent Document 3 requires the removal of the soil discharge blades by pulling up the rod for each process, which is cumbersome and difficult to work with. In addition, because the excavated soil in the empty excavation is discharged in advance, the improved soil expands due to mixing and piles up in the empty excavation, and the improved soil is not sufficiently consolidated, so there is a risk that the columnar improved body will not achieve the designed strength.

[0005] An object of the present invention is to provide a soil removal cover for a columnar ground improvement device and a columnar ground improvement method for solving the problems of the conventional technology as described above. [Means for solving the problem]

[0006] The soil removal cover of the columnar ground improvement device of the present invention is characterized in that it comprises a main body tube that can be fitted onto a drilling rod and a spiral blade attached externally to the main body tube, and the lower part of the main body tube is configured to be freely attached and detached from the upper part of the drilling blade.

[0007] The soil discharge cover of the columnar ground improvement device of the present invention may be configured so that the helical blade has an excavation edge provided at the lower end edge of the helical blade and extending radially from the outer peripheral surface of the main body tube.

[0008] The soil removal cover of the columnar soil improvement device of the present invention may have a spiral blade equipped with a plurality of tip bits arranged in parallel along the excavation edge.

[0009] The soil discharge lid of the columnar soil improvement apparatus of the present invention may have a helical blade that makes one or more revolutions around the outer periphery of the main body tube.

[0010] The soil discharge cover of the columnar soil improvement device of the present invention may be configured so that the main body tube has a soil discharge hole communicating with the peripheral wall.

[0011] The columnar ground improvement method of the present invention comprises a hole drilling process in which an excavation wing is rotated and pressed into the ground using a columnar ground improvement device and a soil removal cover, a soil removal process in which the excavation soil above the penetration depth of the excavation wing is removed, and a columnar improved body is constructed using the improved soil while rotating and pressing the excavation wing below the penetration depth of the excavation wing, and the solidification material is discharged from the excavation wing, and the solidification material is mixed and stirred with the excavated soil to obtain improved soil.The soil removal process is characterized in that the excavation wing is pulled upward, and the excavation soil is pushed up and removed by the spiral blade of the soil removal cover placed on the excavation wing.

[0012] In the columnar ground improvement method of the present invention, in the improvement step, the soil removal lid may be separated from the excavation blade and used as a lid to suppress the heaping of the improved soil due to stirring and mixing.

[0013] The columnar ground improvement method of the present invention includes a removal process for removing the improved soil from the upper part of the columnar improvement body after the improvement process, and in the removal process, the excavation wing can be pulled upward, and the improved soil can be pushed up and removed by the spiral wing of the soil removal cover placed on the excavation wing. Effect of the Invention

[0014] The soil removal cover of the columnar ground improvement device and the columnar ground improvement method of the present invention have at least one of the following effects. <1> By simply lifting the soil discharge cover together with the excavation blade, the excavated soil and improved soil can be easily discharged from the excavation hole, which increases the efficiency of construction. <2> The excavated soil and improved soil can be discharged separately, and only the improved soil can be treated as industrial waste, resulting in low disposal costs. <3> The top level of the columnar improvement body can be easily adjusted by installing the soil discharge cover at the designed top level of the columnar improvement body, and then pulling the soil discharge cover out of the excavation hole after the improvement process to remove the improved soil on top of the soil discharge cover. <4> By holding down the top with a soil removal lid while mixing and stirring the solidification material, the improved soil can be prevented from rising, and the improved soil can be consolidated underground to create a dense and sturdy columnar improved body. [Brief description of the drawings]

[0015] [Figure 1] Diagram of the soil removal cover of the columnar ground improvement device [Diagram 2] Illustration of columnar ground improvement device [Diagram 3] Flow diagram of columnar ground improvement method [Figure 4] Illustration of columnar ground improvement method [Diagram 5] Illustration of columnar ground improvement method [Figure 6] Illustration of columnar ground improvement method [Figure 7] FIG. 2 is an explanatory diagram of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, the soil removal cover of the columnar ground improvement device and the columnar ground improvement method of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0017] <1> Soil removal cover of columnar ground improvement device (Figure 1) The soil discharge cover 1 (hereinafter referred to as "soil discharge cover 1") of the columnar ground improvement device of the present invention is a device that combines a soil discharge function of discharging excavated soil C and improved soil E1 from inside an excavation hole B in the columnar ground improvement method, and a lid function of suppressing the heaping of the improved soil E1 due to stirring and mixing. The soil discharge lid 1 includes at least a main body tube 10 and a helical blade 20 provided on the outside of the main body tube 10. In this example, the number of the helical blade 20 is one. The soil discharge lid 1 is attached to the top of the excavation wing A4 of the excavation rod A3 of the columnar soil improvement device A, and has a structure that allows it to be freely attached and detached from the excavation wing A4.

[0018] <1.1> Pillar-shaped ground improvement device (Fig. 2) The columnar ground improvement device A comprises a body, a long guide A1 that can be installed upright in front of the body, an auger motor A2 that can move vertically along the guide A1, a drilling rod A3 connected to the auger motor A2 at its upper end, a drilling wing A4 attached to the lower end of the drilling rod A3, and a vibration stopper A5 provided at the bottom of the guide A1. The drilling rod A3 moves up and down in conjunction with the movement of the auger motor A2, and is rotated about its axis by the drive of the auger motor A2. The drilling wing A4 rotates in synchronization with the axial rotation of the drilling rod A3. The anti-swaying member A5 holds the drilling rod A3 therein and regulates the rocking caused by the up and down movement of the drilling rod A3. The configuration of the columnar ground improvement device A is publicly known and will not be described in detail here.

[0019] <2> Main body tube The main body tube 10 is a tube that is fitted onto the exterior of the drilling rod A3. The main body tube 10 has at least a cylindrical tubular portion 11, and in this example further has an upper engagement portion 12 provided on the upper edge of the tubular portion 11, a lower engagement portion 13 provided on the lower edge of the tubular portion 11, and a soil discharge hole 14 provided in the peripheral wall of the tubular portion 11. The inner diameter of the cylindrical portion 11 corresponds to the outer diameter of the drilling rod A3. The upper engagement portion 12 is a structure for connecting with the anti-swaying member A5. In this embodiment, the upper engagement portion 12 is a convex structure that engages with a key groove A51 provided in the lower portion of the anti-swaying member A5. The lower engaging portion 13 is a structure for connecting with the excavation wing A4. In this embodiment, the lower engaging portion 13 is a groove-shaped structure that engages with a protrusion A41 provided on the upper portion of the excavation wing A4. The soil discharge hole 14 connects the inside and outside of the peripheral wall of the cylindrical portion 11 . Since the soil discharge lid 1 of the present invention is structured to be fitted to the exterior of the excavation rod A3, if the excavated soil C gets stuck between the excavation rod A3 and the cylindrical part 11, the soil discharge lid 1 may rotate together with the excavation rod A3. In this example, the excavated soil C that has entered the gap between the excavation rod A3 and the cylindrical part 11 is discharged to the outside through the soil discharge hole 14, cutting the edge between the excavation rod A3 and the cylindrical part 11, thereby preventing the soil discharge lid 1 from rotating together.

[0020] <3> spiral wing The spiral blade 20 is a blade-like body that is provided around the main cylinder 10 . The helical blade 20 is attached in a helical shape to the outer periphery of the cylindrical portion 11 along the longitudinal direction of the cylindrical portion 11 . The spiral blade 20 has a generally circular outer shape when the soil discharge lid 1 is viewed from above. The helical blade 20 is desirably structured to make one or more revolutions around the outer periphery of the cylindrical portion 11 in order to effectively perform the function of discharging the excavated soil C and the function of a lid for holding down the improved soil E1. In this example, the helical blade 20 includes a digging edge 21 provided at the lower end edge of the helical blade 20 and a plurality of tip bits 22 provided on the digging edge 21 . The excavation edge 21 is an edge for cutting the helical blade 20 into the soil, and extends radially from the outer circumferential surface of the cylindrical portion 11. The tip bits 22 are bits for cutting hard objects when the excavation arm 21 cuts into the ground, and are arranged in parallel along the width direction of the excavation arm 21.

[0021] <4> Columnar ground improvement method (Figure 3) The columnar ground improvement method of the present invention is a method for constructing a columnar improvement body E in the ground using a columnar ground improvement device A and a soil removal cover 1. In this embodiment, a cement slurry made by mixing a cement-based solidifying agent with water is used as the solidifying material D, but the present invention is not limited to this, and for example, a dry method may be used. The columnar ground improvement method includes at least a hole drilling step S1, a soil removal step S2, and an improvement step S3. In this example, the method further includes a removal step S4 following the improvement step S3.

[0022] <4.1> Construction preparation The columnar ground improvement device A is moved to the construction site, and the guide A1 is set up vertically. The upper part of the drilling rod A3 is hung from the auger motor A2, and the auger motor A2 is moved above the guide A1 to erect the drilling rod A3 along the guide A1. The upper part of the drilling rod A3 is connected to the auger motor A2. The lower part of the drilling rod A3 is held in the anti-sway A5. Before attaching the drilling blade A4 to the drilling rod A3, the soil discharge lid 1 is temporarily fixed to the anti-sway A5. In detail, the upper engagement part 12 of the soil discharge lid 1 is passed through the key groove A51 of the anti-sway A5 and rotated around the axis to engage the upper engagement part 12 with the key groove A51 (FIG. 4). The excavation wing A4 is connected to the lower end of the excavation rod A3, and the upper engagement part 12 is removed from the key groove A51 to remove the soil discharge cover 1 from the anti-sway A5, and the soil discharge cover 1 is placed on the excavation wing A4. At this time, the lower engagement part 13 of the soil discharge cover 1 is fitted into the protrusion A41 of the excavation wing A4, and the soil discharge cover 1 is connected so as to rotate synchronously with the excavation wing A4.

[0023] <4.2>Drilling process The hole drilling step S1 is a step of dry drilling the borehole B. The hole drilling step S1 is performed, for example, as follows. The auger motor A2 of the columnar ground improvement device A is driven to rotate and press the drilling blade A4 at the lower end of the drilling rod A3 into the ground (FIG. 5(1)). As the excavation wing A4 rotates and is pressed in, the soil discharge cover 1 mounted on the excavation wing A4 rotates in synchronization with the excavation wing A4 via the lower engagement portion 13, causing the excavation edge 21 of the spiral wing 20 to cut into the excavated soil C, and the soil discharge cover 1 penetrates into the excavated soil C together with the excavation wing A4. The excavation blade A4 and the soil discharge cover 1 penetrate to a depth where the spiral blade 20 of the soil discharge cover 1 reaches the bottom of the dry excavation.

[0024] <4.3> Earth removal process The soil discharging step S2 is a step of discharging the excavated soil C in the borehole B. The soil discharging step S2 is performed, for example, as follows. The auger motor A2 of the columnar ground improvement device A is moved above the guide A1 without rotating, and the excavation wing A4 is pulled upward into the borehole B, thereby lifting the soil discharge cover 1 mounted on the excavation wing A4 above the height of the construction base surface. This pushes up the excavated soil C above the helical blade 20 at the penetration depth in the hole drilling step S1, and discharges it outside the borehole B (Figure 5 (2)).

[0025] <4.4> Improvement process The improvement step S3 is a step of constructing an improved columnar body E in the ground. The improvement step S3 is carried out, for example, as follows. The soil discharge cover 1 is raised to the ground and the auger motor A2 is moved downward about 10 cm without rotation, thereby disengaging the lower engagement portion 13 of the soil discharge cover 1 from the convex portion A41 of the excavation wing A4, and separating the excavation wing A4 and the soil discharge cover 1 (Figure 5 (3)). While the excavation blade A4 is rotated and pressed downward below the penetration depth of the hole-drilling step S1, the solidification material D is discharged from the nozzle of the excavation blade A4 into the excavated soil C and stirred and mixed. In this way, the excavated soil C is mixed with the solidification material D to form improved soil E1, and a columnar improved body E is constructed in the ground using the cylindrically-kneaded improved soil E1 (Figure 6 (1)). The method of constructing the columnar improved body E itself is known, so it will not be described in detail here.

[0026] <4.4.1> Burying the soil removal cover In this example, in the improvement step S3, the separated soil removal lid 1 is buried on the top of the columnar improved body E to serve as a lid for the improved soil E1 (FIG. 6(1)). The buried depth of the soil removal cover 1 is set so that the spiral blade 20 roughly coincides with the top level of the designed columnar improved body E (i.e., the bottom level of the building foundation). In this way, by covering the top of the columnar improved body E with a soil discharge lid 1 and stirring and mixing the excavated soil C and solidification material D below the soil discharge lid 1, the mounding of the improved soil E1 due to stirring and mixing can be suppressed, and the improved soil E1 can be consolidated underground to construct a dense and sturdy columnar improved body E.

[0027] <4.5>Removal process The removing step S4 is a step of adjusting the top level by removing the improved soil E1 from the upper part of the columnar improved body E. The removing step S4 is carried out, for example, as follows. The auger motor A2 of the columnar ground improvement device A is rotated and moved above the guide A1 (Figure 6 (2)), and the excavation wing A4 is raised above the columnar improvement body E, thereby raising the soil discharge cover 1 mounted on the excavation wing A4 above the height of the construction base surface. This pushes up the improved soil E1 above the helical blades 20 and discharges it outside the borehole B (FIG. 6(3)). The discharged improved soil E1 is disposed of as industrial waste. Since the depth of the spiral blade 20 in the improvement process S3 is the designed top level of the columnar improved body E, the top level of the columnar improved body E can be adjusted by removing the improved soil E1 on the soil disposal cover 1. EXAMPLES

[0028] [Example with two helical blades] In the first embodiment, the soil discharge lid 1 has one spiral blade 20, but the number of the spiral blades 20 is not limited to this. In this example, two helical blades 20 are provided symmetrically around the longitudinal axis of the cylindrical portion 11 (FIG. 7). In this embodiment, the surface area of ​​the helical blade 20 is twice that of the first embodiment, so that both the soil removal function and the lid function can be strengthened. [Explanation of symbols]

[0029] 1 Soil removal lid 10 Main body tube 11 Cylindrical part 12 Upper engagement part 13 Lower engagement part 14 Earth removal hole 20 spiral wing 21 Excavation Edge 22 Tip Bit A Column-shaped ground improvement device A1 Guide A2 Auger motor A3 Drilling Rod A4 Drilling Wing A41 Convex part A5 Anti-vibration A51 key groove B digging holes C excavation D curing material E Columnar Improvement E1 Improved soil S1 Hole cutting process S2 Earthworks S3 Improvement Project S4 Removal Project

Claims

1. A columnar ground improvement device comprising a guide that can be erected on the ground, a drilling rod that can move vertically along the guide, and a drilling wing provided at the lower end of the drilling rod. A soil discharge cover of the columnar ground improvement device is attached to the drilling rod, A main body tube that can be fitted onto the drilling rod; a spiral blade provided on the outside of the main body tube, The lower part of the main body tube is configured to be detachable from the upper part of the excavation wing. Soil discharge cover of columnar ground improvement device.

2. The helical blade is characterized in that it has a digging edge provided at a lower end edge of the helical blade, the digging edge extending radially from an outer circumferential surface of the main body tube. A soil discharge lid for the columnar ground improvement device according to claim 1.

3. The helical blade is characterized in that it has a plurality of tip bits arranged in parallel along the excavation edge. A soil removal cover for the columnar ground improvement device according to claim 2.

4. The spiral blade is configured to rotate around the outer periphery of the main body tube at least once. A soil discharge lid for the columnar ground improvement device according to claim 1.

5. The main body tube is characterized in that it has a soil discharge hole communicating with the peripheral wall. A soil discharge lid for the columnar ground improvement device according to claim 1.

6. A columnar ground improvement method for constructing a columnar improvement body in the ground using the columnar ground improvement device and the soil removal cover according to any one of claims 1 to 5, A drilling step of penetrating the drilling blade into the ground by rotating and pressing the drilling blade; A soil discharge process for discharging excavated soil above the penetration depth of the excavation wing; An improvement process in which the excavation blade is rotated and pressed downward below the penetration depth of the excavation blade, a solidification material is discharged from the excavation blade, the solidification material is mixed with the excavated soil to form improved soil, and a columnar improved body is constructed using the improved soil. In the soil discharge step, the excavation wing is raised upward, and the excavated soil is pushed up and discharged by the spiral wing of the soil discharge cover placed on the excavation wing. Columnar ground improvement method.

7. In the improving step, the soil dumping cover is separated from the excavation wing; It is characterized by being used as a lid to suppress the rise of the improved soil due to stirring and mixing. The columnar ground improvement method according to claim 6.

8. A removal process is provided for removing the improved soil from the upper part of the columnar improvement body after the improvement process; In the removing step, the excavation wing is raised upward, and the improved soil is pushed up and removed by the spiral wing of the soil removal lid placed on the excavation wing. The columnar ground improvement method according to claim 6.

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