JP2016135971A - Joint member of casing segment used in micro pile method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint member of a casing segment used in a micro pile method that has an advantage in improving an efficiency of a process to pull out the casing segment.SOLUTION: A joint member 10 has a cylindrical body part 12 with an outer diameter larger than that of a casing segment. The body part 12 has a connection part 14 and a tooth part 16. The connection part 14, into which an end part of the casing segment is inserted and connected, is formed on an inner peripheral part of the body part 12. The connection part 14 has a female screw 1402 formed on the inner peripheral part of the body part 12. The female screw 1402 can screwed together with a male screw on the end part of the casing segment. The tooth part 16 is formed both ends of the joint member 10 in an axial direction and positioned outside in radial direction of the casing segment connected to the joint member 10, and shoves bored earth away during rotation of the casing segment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a joint member for a casing segment used in a micropile method.

The micropile construction method is a generic name for small-sized cast-in-place piles with a diameter of 300 mm or less, for reasons such as being sufficient with compact construction equipment, being able to be constructed in a narrow space, and being able to be constructed without stopping the functions of existing structures. It is used for various purposes including seismic reinforcement of existing structures, ground reinforcement, and stabilization of slopes.
In the micropile method, first, the first rod having a drilling drill attached to the tip is inserted into the first casing segment whose outer periphery is the outer drilling cutter. A step of drilling while rotating the casing segment and the rod and injecting water is performed.
Then, at each predetermined depth, the next casing segment is detachably connected to the end of the casing segment via a joint member and added, and the next rod is detachably connected to the end of the rod. The process of adding holes, rotating the casing segment and the rod, and drilling while injecting water is performed.
The outer diameter of the outer hole cutter is larger than the outer diameter of the casing segment in consideration of the outer diameter of the joint member. After drilling, a gap is formed between the hole wall surface and the outer peripheral surface of the casing segment. Is done.

Next, when the drilled hole reaches a predetermined depth, a step of pulling out the drill with the rod from the inside of the casing segment is performed.
Next, if necessary, a reinforcing material is disposed inside the casing over the entire length of the casing.
Next, a process of drawing a predetermined length while rotating the casing segment while filling the grout material is performed.
In such a micropile method, the joint member connects the end portions of the casing segment at the inner periphery thereof, and the outer diameter of the joint member is larger than the outer diameter of the casing segment.

Patent No. 4010383

Therefore, in the conventional micropile method, the following problems occur in the process of pulling out the casing segment after drilling.
That is, although a gap is formed between the hole wall surface and the outer peripheral surface of the casing segment after drilling, the gap is filled with excavated soil that has collapsed from the hole wall surface, so that the casing segment is tightened by the excavated soil. It becomes a state. At this time, the portion of the joint member that protrudes radially outward of the casing segment at the connecting portion of the casing segment is also buried in the excavated soil and is tightened by the excavated soil.
Therefore, if the casing segment is pulled out while rotating, the joint member portion that is buried and tightened in the excavated soil has a high resistance, and the casing segment has a high pulling resistance. Therefore, it takes a long time to pull out the casing segment. Is needed.
In addition, when the casing segment is pulled out, there is a limit in reducing the pulling resistance even if the casing segment is rotated and the casing segment is vibrated in the axial direction (rotary percussion).

Specifically, the length of the casing segment is 1.5 to 3 m. Therefore, for example, to drill a depth of 54 m, even if a casing segment having a length of 3 m is used, 18 casing segments are required, and 17 joint members are required.
Accordingly, when the casing segment is pulled out, the joint member has a maximum of 17 resistances, and the resistance at the time of pulling out the casing segment is increased. Therefore, some improvement has been desired.

  The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a joint member for a casing segment used in the micropile method, which is advantageous in increasing the efficiency of the drawing process of the casing segment. Is to provide.

In order to achieve the object, the invention according to claim 1 is characterized in that the casing segment is added and separated by a micropile method comprising a step of drilling while rotating the casing segment and a step of pulling out the casing segment while rotating. A tubular joint member provided with a connecting portion to which an end portion of the casing segment is inserted and connected to an inner peripheral portion thereof, at both ends in the axial direction of the joint member, It is characterized in that there are provided teeth that are located radially outside the connected casing segments and scrape the excavated soil when the casing segments rotate.
The invention according to claim 2 is characterized in that the joint member includes a cylindrical main body portion having an outer diameter larger than an outer diameter of the casing segment and having the connecting portion provided on an inner peripheral portion thereof. A plurality of tooth portions are provided at both ends in the axial direction of the main body portion at intervals in the circumferential direction.
According to a third aspect of the present invention, the outer diameter of the main body is formed with a uniform dimension along the axial direction of the main body.
The invention according to claim 4 is characterized in that the outer diameters of both ends in the axial direction of the main body are formed so as to gradually decrease toward the end in the axial direction of the main body.
The invention according to claim 5 is characterized in that the outer peripheral surface and the inner peripheral surface of the main body portion intersect at an acute angle at both axial ends of the main body portion.
The invention according to claim 6 is characterized in that the outer peripheral surface and the inner peripheral surface of the main body portion are connected via an annular thin portion at both axial ends of the main body portion.

According to the first aspect of the present invention, the joint member is tightened by the excavated soil by scraping the excavated soil by both of the tooth portions provided at both ends of the joint member in the axial direction in the casing segment pulling process. The condition is relaxed and the pulling resistance of the casing segment is reduced.
Therefore, the time required for pulling out the casing segment can be shortened, which is advantageous in increasing the working efficiency of the micropile method.
According to the second aspect of the present invention, the excavated soil can be efficiently scraped with a simple configuration when the casing segment is extracted and the vibration is generated in the extraction process, and the time required for extracting the casing segment can be shortened. This is advantageous in increasing the work efficiency of the method.
According to the third aspect of the invention, in the casing segment drawing process, it is advantageous to reduce the resistance of the joint member and efficiently perform the drawing operation of the casing segment.
According to the fourth, fifth, and sixth aspects of the present invention, when the casing segment is pulled out while being rotated in the casing segment pulling process, the inclined surface hits the excavated soil in addition to the tooth portion, so that the excavated soil collapsed from the hole wall surface. This is advantageous in efficiently removing the casing segment.

It is a front view of a joint member. It is a side view of a joint member. It is a section front view in the state where a casing segment was connected with a joint member. (A)-(G) are explanatory drawings of a micropile construction method. It is explanatory drawing of another Example 1 of a coupling member. It is explanatory drawing of another Example 2 of a coupling member. It is explanatory drawing of another Example 3 of a coupling member. It is explanatory drawing of another Example 4 of a coupling member.

Embodiments of a joint member for a casing segment used in the micropile method according to the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 to 3, the joint member 10 includes a cylindrical main body 12 having an outer diameter larger than the outer diameter of the casing segment 18.
The outer diameter of the main body 12 is formed with a uniform dimension along the axial direction of the main body 12.
The main body 12 includes a connecting portion 14 and a tooth portion 16.
The connecting portion 14 is provided at the inner peripheral portion of the main body portion 12 and is a place where the end portion of the casing segment 18 is inserted and connected.
In the present embodiment, the connecting portion 14 is configured by a female screw 1402 provided on the inner peripheral portion of the main body portion 12. The female screw 1402 can be screwed into the male screw 1802 at the end of the casing segment 18.
The tooth portions 16 are provided at both ends in the axial direction of the joint member 10, are located on the radially outer side of the casing segment 18 connected to the joint member 10, and scrape excavated soil when the casing segment 18 rotates.
In the present embodiment, a plurality of tooth portions 16 are provided at both ends in the axial direction of the main body portion 12 at intervals in the circumferential direction. In FIG. 1, reference numeral 1602 indicates a crest of the tooth portion 16. Reference numeral 1604 denotes a trough of the tooth portion 16.

Next, the micropile method using the joint member 10 will be described with reference to FIG.
As shown in FIG. 4 (A), when the micropile method is applied, the tip end outer peripheral portion is set as the outer drilling cutter 20 inside the first elongated hollow cylindrical steel casing segment 18, The first rod 24 to which the drilling hole 22 is attached is inserted, and the casing segment 18 and the rod 24 are rotated, and water is poured into the outer drilling cutter 20 and the drilling drill 22. The process of drilling the hole 26 is performed.
4 (B) and 4 (C), each time the hole 26 reaches a predetermined depth, the following elongated hollow cylindrical steel casing segment 18 is connected to the end of the casing segment 18 as a joint member. 10 is removably connected through 10 and the next rod 24 is removably connected to the end of the rod 24 to rotate, the casing segment 18 and the rod 24 are rotated, and water is injected. Meanwhile, the step of drilling the hole 26 with the outer hole cutter 20 and the hole drill 22 is performed.
As shown in FIG. 3, the casing segment 18 is connected by screwing the male screw 1802 at the end of the casing segment 18 into the female screw 1402 of the main body 12.
The outer diameter of the outer hole cutter 20 is larger than the outer diameter of the casing segment 18 in consideration of the outer diameter of the joint member 10.
In the present embodiment, the outer hole cutter 20 protrudes 15 mm outward from the outer peripheral surface of the casing segment 18 in the radial direction of the casing segment 18, and the joint member 10 extends from the outer peripheral surface of the casing segment 18 to the casing segment 18. It protrudes 10 mm outward in the radial direction.

Casing C is constituted by connecting a plurality of casing segments 18.
As shown in FIG. 4C, when the drilled hole 26 passes through the soft layer 28 and reaches a predetermined depth of the load support layer 30, the drilling drill 22 and the rod 24 are connected to the inside of the casing C. The process of drawing from is performed.
Next, a reinforcing material such as a reinforcing bar is disposed inside the casing C over the entire length of the casing C as necessary.

Next, as shown in FIG. 4D, the grout material G is filled into the casing C using a tremy tube (not shown).
As the grout material G, cement milk, mortar material, or a concrete material mixed with a small diameter aggregate can be used.
Next, as shown in FIG. 4E, a step of pulling out the casing C, that is, a step of pulling out the casing segment 18 is performed while the grout material G is injected under pressure into the casing C.
It is desirable that the grouting material G be pressed at such a pressure that the grouting material G comes into close contact with the wall surface of the hole 26 that has been drilled, and the joining state between the grouting material G and the ground becomes strong.
The casing C is pulled out by gripping the lower casing segment 18 so that it cannot rotate when the upper end of the lower casing segment 18 is positioned on the ground among the upper and lower adjacent casing segments 18. And the upper casing segment 18 is removed from the lower casing segment 18 together with the joint member 10.
A plurality of casing segments 18 positioned above are removed together with the joint member 10, and the lower end of the first casing segment 18 positioned at the lowest position is the uppermost portion of the load support layer 30 as shown in FIG. When it approaches, the extraction of the casing C is completed.

Next, as shown in FIG. 4 (F), a step of pushing the casing C back into the grout material G in which the grout material G is pressure-filled by a predetermined amount is performed, and the portion surrounded by the casing C, the casing A portion having an intermediate structure is created between the portion not surrounded by C.
And the pile body 30 which has 32 A of ground junction parts by the grout material G is obtained because the grout material G is hardened | cured.
Next, as shown in FIG. 4G, a steel bearing plate 34 is joined to the upper end of the casing C by welding, and a connection structure for connecting the pile head of the pile body 32 to the structure is formed. Is done.

The process of pulling out the casing segment 18 shown in FIG. 4 (E) will be further described.
Since the outer diameter of the outer hole cutter 20 is larger than the outer diameter of the casing segment 18, a gap is generated between the hole wall surface formed by the outer hole cutter 20 and the outer peripheral surface of the casing segment 18. .
However, since this gap is filled with excavated soil broken from the hole wall surface, the casing segment 18 is tightened by the excavated soil. At this time, the portion of the joint member 10 protruding outward in the radial direction of the casing segment 18 is also buried in the excavated soil and is tightened by the excavated soil.
Here, when the casing segment 18 is pulled out while being rotated, the tooth portion 16 located on the upper side among the tooth portions 16 rotating together with the joint member 10 scrapes the excavated soil filling the gap. That is, the excavated soil is scraped off by the teeth 16 located on the upper side, so that the state in which the joint member 10 is tightened by the excavated soil is relaxed, and the pulling resistance of the casing segment 18 is reduced.
Further, when the casing segment 18 is pulled out and the casing segment 18 is rotated and the casing segment 18 is vibrated in the axial direction, excavation is performed by both the tooth portions 16 provided at both ends of the joint member 10 in the axial direction. By separating the soil, the state in which the joint member 10 is tightened by the excavated soil is further relaxed, and the pull-out resistance of the casing segment 18 is further reduced.
Therefore, the time required for pulling out the casing segment 18 can be shortened, which is advantageous in increasing the working efficiency of the micropile method.

Specifically, for example, in order to drill a depth of 54 m, even if a casing segment 18 having a length of 3 m is used, 18 casing segments 18 are required, and 17 joint members 10 are required. Become.
Therefore, according to the present embodiment, when the casing segment 18 is pulled out, the resistance caused by the joint member 10 is generated at 17 places at the maximum, and the conventional problem that the casing segment 18 cannot be pulled out efficiently can be solved.
That is, it is advantageous in increasing the efficiency of the drawing process of the casing segment 18, and it is advantageous in greatly reducing the work period of the micropile method and reducing the cost.

In the present embodiment, a plurality of tooth portions 16 are provided at both ends in the axial direction of the main body portion 12 at intervals in the circumferential direction.
Therefore, when the casing segment 18 is pulled and the vibration is generated in the pulling process, the excavated soil can be efficiently scraped with a simple configuration, the time required for pulling out the casing segment 18 can be shortened, and the working efficiency of the micropile method is increased. This is advantageous.

Further, in the present embodiment, the outer diameter of the main body 12 is formed with a uniform dimension along the axial direction of the main body 12.
Therefore, in the process of pulling out the casing segment 18, it is advantageous for reducing the resistance of the joint member 10 and performing the pulling out operation of the casing segment 18 efficiently.

Next, another embodiment of the joint member 10 will be described with reference to FIGS.
5-8, (A) shows the front view of the tooth | gear part 16, (B1), (C1), (D1), (E1) is XX sectional drawing of (A), (B2), (C2), (D2), and (E2) are YY cross-sectional views of (A).
In these other embodiments, the outer diameter of the main body 12 is not uniform along the axial direction of the main body 12, but reaches the end at both axial ends of the main body 12 where the teeth 16 are provided. The outer diameter is provided to be small.

More specifically, in another embodiment 1 shown in FIG. 5, the tooth portion 16 includes a plurality of semicircular valleys 1604 arranged at intervals in the circumferential direction of the main body portion 12, and a gap 1602 between them. Is made up of.
And in another Example 1 shown to FIG. 5 (A), (B1), (B2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided, so that it may reach an edge part. An inclined surface 1610 made of a conical surface is formed.
5 (A), (C1), and (C2), the outer diameter of the main body 12 is increased toward both ends in the axial direction of the main body 12 where the teeth 16 are provided. An inclined surface 1612 made of a curved curved surface is formed on the outer side in the radial direction of the main body 12 to reduce the height.
Moreover, in another Example 1 shown to FIG. 5 (A), (D1), (D2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided until it reaches an edge part. An inclined surface 1614 made of a curved surface recessed inward in the radial direction of the main body portion 12 is formed.

Moreover, in another Example 1 shown to FIG. 5 (A), (E1), (E2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided until it reaches an edge part. An inclined surface 1616 made of a conical surface is made small. In another embodiment 1 shown in FIGS. 5A, 5 </ b> B, and 2 </ b> B, the outer peripheral surface 12 </ b> A and the inner peripheral surface 12 </ b> B of the main body 12 intersect at an acute angle at both axial ends of the main body 12. However, in contrast to the pointed shape, in another example 1 shown in FIGS. 5A, 5E, and 5E, both ends in the axial direction of the main body 12 are given a thickness, The outer peripheral surface 12 </ b> A and the inner peripheral surface 12 </ b> B of the main body 12 are connected via an annular thin portion 1618. Thus, the structure which gave thickness to the both ends of the axial direction of the main-body part 12 is another Example 1 shown to FIG. 5 (A), (C1), (C2), FIG. 5 (A), (D1). Of course, the present invention can also be applied to another embodiment 1 shown in (D2).
According to such another embodiment 1, when the casing segment 18 is pulled out while being rotated in the drawing process of the casing segment 18, the inclined surface hits the excavated soil in addition to the tooth portion 16, so that the excavated soil collapsed from the hole wall surface. Is efficiently performed, which is advantageous in efficiently pulling out the casing segment 18.

Next, another embodiment 2 shown in FIG. 6 will be described.
In another embodiment 2 shown in FIG. 6, the tooth portion 16 is configured by arranging a plurality of pentagonal valleys 1604 at intervals in the circumferential direction of the main body portion 12, and forming a crest 1602 between them. Yes.
And in another Example 2 shown to FIG. 6 (A), (B1), (B2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided until it reaches an edge part. An inclined surface 1620 made of a conical surface is formed to reduce the height.
Moreover, in another Example 2 shown to FIG. 6 (A), (C1), (C2), the outer diameter of the main-body part 12 is reached to the edge part at the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided. An inclined surface 1622 made of a curved curved surface is formed on the outer side in the radial direction of the main body 12 to reduce the height.
Moreover, in another Example 2 shown to FIG. 6 (A), (D1), (D2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided until it reaches an edge part. An inclined surface 1624 made of a curved surface that is recessed inward in the radial direction of the main body 12 is formed.

Moreover, in another Example 2 shown to FIG. 6 (A), (E1), (E2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided, so that it may reach an edge part. An inclined surface 1626 made of a conical surface is formed to reduce the height. In another embodiment 2 shown in FIGS. 6A, 6 </ b> B <b> 1, and 2 </ b> B <b> 2, the outer peripheral surface 12 </ b> A and the inner peripheral surface 12 </ b> B of the main body 12 intersect at an acute angle at both axial ends of the main body 12. However, in contrast to the pointed shape, in another example 2 shown in FIGS. 6A, 6E, and 2E, thickness is given to both ends of the main body 12 in the axial direction, The outer peripheral surface 12 </ b> A and the inner peripheral surface 12 </ b> B of the main body 12 are connected via an annular thin portion 1628. Thus, the structure which gave thickness to the both ends of the axial direction of the main-body part 12 is another Example 2 shown to FIG. 6 (A), (C1), (C2), FIG. 6 (A), (D1). Of course, the present invention can also be applied to the second embodiment shown in (D2).
According to the second embodiment, as in the first embodiment, in the step of pulling out the casing segment 18, the excavated soil broken from the hole wall surface is efficiently scraped, and the pulling out operation of the casing segment 18 is performed. This is advantageous for efficient operation.

Next, another embodiment 3 shown in FIG. 7 will be described.
In another embodiment 3 shown in FIG. 7, the crest 1602 and the trough 1604 of the tooth portion 16 are each formed in a horizontally long rectangle in the circumferential direction of the main body portion 12.
And in another Example 3 shown to FIG. 7 (A), (B1), (B2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided, so that it reaches an edge part. An inclined surface 1630 made of a conical surface is formed.
Moreover, in another Example 3 shown to FIG. 7 (A), (C1), (C2), the outer diameter of the main-body part 12 is reached to the edge part at the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided. An inclined surface 1632 made of a curved curved surface is formed on the outer side in the radial direction of the main body 12 to reduce the height.
Moreover, in another Example 3 shown to FIG. 7 (A), (D1), (D2), the outer diameter of the main-body part 12 is reached to the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided, and reaches an edge part. An inclined surface 1634 made of a curved surface that is recessed inward in the radial direction of the main body 12 is formed.

Moreover, in another Example 3 shown to FIG. 7 (A), (E1), (E2), the outer diameter of the main-body part 12 is reached to the edge part at the both ends of the axial direction of the main-body part 12 in which the tooth | gear part 16 is provided. An inclined surface 1636 made of a conical surface is formed to reduce the height. In another embodiment 3 shown in FIGS. 7A, 7B, and 2B, the outer peripheral surface 12A and the inner peripheral surface 12B of the main body 12 intersect at an acute angle at both ends in the axial direction of the main body 12. However, in contrast to the pointed shape, in another embodiment 3 shown in FIGS. 7A, 7E, and 2E, thickness is given to both ends in the axial direction of the main body portion 12, The outer peripheral surface 12 </ b> A and the inner peripheral surface 12 </ b> B of the main body 12 are connected via an annular thin portion 1638. Thus, the structure which gave thickness to the both ends of the axial direction of the main-body part 12 is another Example 3 shown to FIG. 7 (A), (C1), (C2), FIG. 7 (A), (D1). Of course, the present invention can also be applied to the third embodiment shown in (D2).
According to the third embodiment, as in the first and second embodiments, in the process of pulling out the casing segment 18, the excavated soil broken from the hole wall surface is efficiently scraped, and the casing segment 18 is pulled out. This is advantageous for efficient work.

Next, another embodiment 4 shown in FIG. 8 will be described.
In another embodiment 4 shown in FIG. 8, like the third embodiment, the crest 1602 and the valley 1604 of the tooth portion 16 are each formed in a horizontally long rectangle in the circumferential direction of the main body portion 12.
In another example 4, two inclined surfaces 1640 and 1642 having different inclination angles are formed at both ends of the main body 12 in the axial direction.
That is, in another embodiment 4 shown in FIGS. 8A, 8 </ b> B <b> 1, and 2 </ b> B <b> 2, the crest 1602 of the tooth portion 16 increases the outer diameter of the main body portion 12 toward the end of the main body portion 12 in the axial direction. A first inclined surface 1640 made of a conical surface to be reduced is formed. In addition, the valley 1604 of the tooth portion 16 has a second conical surface made of a conical surface having a smaller outer diameter and a larger inclination angle than the first inclined surface 1640 as it reaches the axial end of the main body portion 12. An inclined surface 1642 is formed.

Moreover, in the other Example 4 shown to FIG. 8 (A), (C1), (C2), like the other Example 4 shown to FIG. 8 (A), (B1), (B2), it is the tooth | gear part 16 of FIG. The crest 1602 is formed with a third inclined surface 1644, and the trough 1604 of the tooth portion 16 is formed with a fourth inclined surface 1646 having a larger inclination angle than the third inclined surface 1644. In another embodiment 4 shown in FIGS. 8A, 8 </ b> B <b> 1, and 2 </ b> B 2, the outer peripheral surface 12 </ b> A and the inner peripheral surface 12 </ b> B of the main body 12 intersect at an acute angle at both ends in the axial direction of the main body 12. However, in the fourth embodiment shown in FIGS. 8A, 8 </ b> C <b> 1, and 8 </ b> C 2, the tip portion of the peak 1602 and the bottom portion of the valley 1604 have a thickness. The outer peripheral surface 12A and the inner peripheral surface 12B of the main body portion 12 are connected via an annular thin portion 1648A at the tip of the mountain 1602, and the outer peripheral surface 12A and the inner peripheral surface 12B of the main body portion 12 at the bottom of the valley 1604. Are connected via an annular thin portion 1648B. The first to fourth inclined surfaces 1640, 1642, 1644, and 1646 are curved surfaces shown in FIGS. 7A, 7C1, and 2C of another embodiment 3 and FIGS. 7A and 7D. ), A curved surface shown in (D2).
According to such another embodiment 4, when the casing segment 18 is pulled out while being rotated in the drawing process of the casing segment 18, the two inclined surfaces having different inclination angles in addition to the tooth portion 16 hit the excavated soil. The excavated soil that has collapsed from the wall surface is efficiently scraped, which is advantageous in efficiently pulling out the casing segment 18.
According to such another embodiment 4, when the casing segment 18 is pulled out while being rotated in the drawing process of the casing segment 18, in addition to the tooth portion 16, two inclined surfaces having different inclination angles hit the excavated soil. Scraping of excavated soil that has collapsed from the hole wall surface is performed efficiently, which is advantageous in efficiently pulling out the casing segment 18.

The structure of the connecting portion 14 for connecting the casing segment 18 can employ various conventionally known structures such as pin coupling, but the connecting portion 14 is connected to the end of the casing segment 18 as in the embodiment. The configuration of the female screw 1402 that is screwed to the male screw 1802 is advantageous in simplifying the configuration of the connecting portion 14.
Moreover, the structure of the tooth | gear part 16 is not limited to embodiment, A conventionally well-known various structure is employable, and what is necessary is just a structure with which the function which scrapes excavated soil by rotating is played in short.

DESCRIPTION OF SYMBOLS 10 Joint member 12 Main-body part 14 Connection part 16 Teeth part 1602 Teeth crest 1604 Teeth trough 18 Casing segment

Claims (6)

The micro-pile method includes a step of drilling while rotating the casing segment, and a step of pulling out the casing segment while rotating the casing segment, and is used for adding and separating the casing segment. Is a cylindrical joint member provided with a connecting portion to be inserted and connected,
At both ends in the axial direction of the joint member, tooth portions that are located radially outward of the casing segment connected to the joint member and scrape excavated soil when the casing segment rotates are provided.
A joint member for a casing segment used in the micropile method. The joint member includes a cylindrical main body having an outer diameter larger than an outer diameter of the casing segment and having the connecting portion provided on an inner peripheral portion thereof.
A plurality of the tooth portions are provided at both ends in the axial direction of the main body portion at intervals in the circumferential direction.
A joint member for a casing segment used in the micropile method according to claim 1. The outer diameter of the main body is formed with a uniform dimension along the axial direction of the main body,
A joint member for a casing segment used in the micropile method according to claim 2. The outer diameter of both ends in the axial direction of the main body is formed so as to gradually decrease as it reaches the end in the axial direction of the main body.
A joint member for a casing segment used in the micropile method according to claim 2. At both ends in the axial direction of the main body portion, the outer peripheral surface and the inner peripheral surface of the main body portion intersect at an acute angle,
The joint member of the casing segment used with the micropile construction method of Claim 4 characterized by the above-mentioned. At both ends in the axial direction of the main body, the outer peripheral surface and the inner peripheral surface of the main body are connected via an annular thin portion.
The joint member of the casing segment used with the micropile construction method of Claim 4 characterized by the above-mentioned.

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