WO2020184282A1 - Steel pipe pile and method for installing steel pipe pile - Google Patents
Steel pipe pile and method for installing steel pipe pile Download PDFInfo
- Publication number
- WO2020184282A1 WO2020184282A1 PCT/JP2020/008862 JP2020008862W WO2020184282A1 WO 2020184282 A1 WO2020184282 A1 WO 2020184282A1 JP 2020008862 W JP2020008862 W JP 2020008862W WO 2020184282 A1 WO2020184282 A1 WO 2020184282A1
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- WIPO (PCT)
- Prior art keywords
- steel pipe
- excavation bit
- pipe pile
- pipe body
- excavation
- Prior art date
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 269
- 239000010959 steel Substances 0.000 title claims abstract description 269
- 238000000034 method Methods 0.000 title claims description 16
- 238000009412 basement excavation Methods 0.000 claims description 275
- 238000010276 construction Methods 0.000 claims description 22
- 239000004576 sand Substances 0.000 claims description 17
- 238000005553 drilling Methods 0.000 abstract description 29
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 17
- 230000004048 modification Effects 0.000 description 11
- 238000012986 modification Methods 0.000 description 11
- 239000002689 soil Substances 0.000 description 11
- 230000000694 effects Effects 0.000 description 8
- 230000001737 promoting effect Effects 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 5
- 239000013049 sediment Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 238000009499 grossing Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/24—Prefabricated piles
- E02D5/28—Prefabricated piles made of steel or other metals
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/56—Screw piles
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D7/00—Methods or apparatus for placing sheet pile bulkheads, piles, mouldpipes, or other moulds
- E02D7/22—Placing by screwing down
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B3/00—Rotary drilling
- E21B3/02—Surface drives for rotary drilling
Definitions
- the present invention relates to a steel pipe pile and a method for constructing a steel pipe pile.
- the excavation bit attached to the tip of the steel pipe pile is expected to have the effect of controlling the movement of the excavated soil according to the rotation direction of the pile and suppressing or promoting the blockage of the soil inside the pipe, in addition to the conventional effect of excavating the ground.
- the central axis in the longitudinal direction of the excavation bit and the tangential direction at the intersection of the outer periphery of the steel pipe pile have an angle, and the cutting edge of the excavation bit is directed toward the inside of the steel pipe pile by this angle.
- the earth and sand are pushed out to the outside of the pile to suppress the blockage of the soil in the pipe, thereby improving the excavability, and after the pile tip reaches the support layer, the pile.
- the earth and sand are taken into the inside of the pile, and high bearing capacity can be obtained by promoting the blockage of the soil inside the pipe.
- an object of the present invention is to provide a new and improved method for constructing steel pipe piles and steel pipe piles, which can maintain the function of the excavation bit against wear during excavation.
- a steel pipe pile provided with a steel pipe body and a plate-shaped excavation bit that is attached to the end surface of the steel pipe body at an angle with respect to the circumferential tangent line of the steel pipe body and projects in the axial direction of the steel pipe body.
- a first excavation bit projecting from the end face of the steel pipe body in the axial direction of the steel pipe body by the first height, and a second height higher than the first height in the axial direction of the steel pipe body from the end face of the steel pipe body.
- a steel pipe pile including a second drilling bit that protrudes so much.
- An inclination is formed on the tip surface of at least one of the first excavation bit and the second excavation bit so that the protrusion height increases from the inside to the outside in the radial direction of the steel pipe body [1].
- Steel pipe pile described in. [3] According to [1] or [2], at least one of the first excavation bit and the second excavation bit is formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body.
- the first drilling bit is attached at a first angle with respect to the circumferential tangent of the steel pipe body, and the second drilling bit is larger than the first angle with respect to the circumferential tangent of the steel pipe body.
- the first excavation bit has a first length along the attachment direction of the first excavation bit, and the second excavation bit is the first along the attachment direction of the second excavation bit.
- Construction method of steel pipe pile including the process of excavating while rotating the pile.
- the construction resistance is borne by the second excavation bit having a higher protrusion height, and the wear of the first excavation bit can be suppressed by that amount. Therefore, the function of the excavation bit can be maintained against the wear during excavation.
- FIG. 1 is a view of a steel pipe pile according to a first embodiment of the present invention as viewed from the side and the tip side.
- the steel pipe pile 10 includes a steel pipe main body 11 and a drilling bit 12 attached to an end surface 11E of the steel pipe main body 11 and protruding in the axial direction of the steel pipe main body 11.
- the excavation bit 12 includes a first excavation bit 121 and a second excavation bit 122.
- both the first excavation bit 121 and the second excavation bit 122 are attached at an angle ⁇ (0 ⁇ ⁇ 90 °) with respect to the circumferential tangent of the steel pipe body 11.
- the angle theta, the thickness center line L C12 plate-like drill bit 12 is at a position intersecting the wall thickness center line L C11 steel pipe body 11, the thickness center line L C12 and the pipe thickness center line L C11 This is the angle formed by the tangent line LT11 (the circumferential tangent line of the steel pipe body 11).
- the angle ⁇ is also referred to as the mounting angle of the excavation bit 12.
- the attachment directions of the first excavation bit 121 and the second excavation bit 122 are directions tilted by the respective attachment angles ⁇ 1 and ⁇ 2 with respect to the circumferential tangent of the steel pipe main body 11.
- the steel pipe pile 10 is rotated counterclockwise as shown in FIG. 1 until the tip of the pile reaches a predetermined depth, for example, during excavation using the steel pipe pile 10. It is possible to excavate while rotating to (CCW) and push the earth and sand to the outside of the steel pipe main body 11 to suppress the blockage of the soil inside the pipe. Further, the steel pipe pile 10 is excavated while rotating clockwise (CW) shown in FIG. 1 until the tip of the pile reaches the stopping depth, and the earth and sand are taken into the inside of the steel pipe main body 11 to promote the blockage of the soil inside the pipe. By doing so, high support can be obtained.
- the excavation bit 12 has edges both inside and outside in the radial direction of the steel pipe body 11, which enables excavation by reversing the rotation direction of the steel pipe body 11 as described above.
- both the first excavation bit 121 and the second excavation bit 122 project to both the outside and the inside of the steel pipe body 11 in the radial direction, and the pipe thickness of the steel pipe body 11 is centered in the mounting direction. Crosses the center line LC11 .
- the excavation bit may protrude only to either the outside or the inside in the radial direction of the steel pipe body 11.
- the first drill bit 121 by a height H 1 protrudes from the end surface 11E of the steel pipe body 11 in the axial direction of the steel pipe body 11 of the drill bit 12, the second drill bit 122 steel body 11
- the height H 2 protrudes from the end surface 11E of the steel pipe body 11 in the axial direction by the height H 2
- the height H 2 is higher than the height H 1 (H 1 ⁇ H 2 ).
- the second excavation bit that precedes in the excavation It is possible to make the 122 bear the construction resistance and suppress the wear of the first excavation bit 121 whose construction resistance is reduced by that amount.
- the wear of the first excavation bit 121 becomes remarkable, for example, after the protruding height of the second excavation bit 122 becomes about the same as that of the first excavation bit 121 due to the wear. In some cases, the wear of the excavation bit 121 of 1 is not remarkable.
- the method of attaching the excavation bit 12 to the steel pipe body 11 may be, for example, welding or mechanical joining means such as screwing.
- the end surface 11E of the steel pipe body 11 and the upper end surface of the excavation bit 12 coincide with each other, but the excavation bit 12 is fitted into, for example, a groove or a notch formed in the end surface 11E. It can be joined above, or it can be joined after fitting the end of the steel pipe body 11 including the end face 11E into the groove or notch formed in the upper end surface of the excavation bit 12, or the end face 11E and the upper end surface of the excavation bit 12. It is possible to form grooves or notches in both of them so that these grooves or notches fit together and then join. In this case, the end surface 11E of the steel pipe body 11 and the upper end surface of the excavation bit 12 do not always match. The same applies to the other examples described below.
- FIG. 4 is a diagram showing another example of the steel pipe pile according to the first embodiment of the present invention.
- the first excavation bit 121A and the second excavation bit 122A included in the excavation bit 12 have a mounting angle ⁇ as in the example described with reference to FIG. 1 above.
- the protrusion height H 2 of the second excavation bit 122A is higher than the protrusion height H 1 of the first excavation bit 121A.
- the tip surfaces 121E and 122E of the first excavation bit 121A and the second excavation bit 122A that is, the end surface of the steel pipe body 11 opposite to the end surface 11E, in the radial direction of the steel pipe body 11.
- a slope is formed in which the protruding height increases from the inside to the outside of the pipe.
- the protrusion height of the first excavation bit 121A and the second excavation bit 122A becomes higher in the portion that comes into contact with the earth and sand in advance, and the resistance to wear of the first excavation bit 121A and the second excavation bit 122A is increased. Can be improved.
- the protruding heights H 1 and H 2 of the first excavation bit 121A and the second excavation bit 122A are, for example, the heights from the end surface 11E to the highest position of the inclined tip surfaces 121E and 122E as shown in the figure. Can be defined as. Further, in the illustrated example, both the tip surfaces 121E and 122E of the first excavation bit 121A and the second excavation bit 122A are inclined, but only one of the tip surfaces is inclined. May be good.
- FIG. 5 is a diagram showing still another example of the steel pipe pile according to the first embodiment of the present invention.
- the first excavation bit 121 and the second excavation bit 122B included in the excavation bit 12 have a mounting angle ⁇ as in the example described with reference to FIG. 1 above.
- the protrusion height H 2 of the second excavation bit 122B is higher than the protrusion height H 1 of the first excavation bit 121.
- the second excavation bit 122B is formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body 11.
- the second excavation bit 122B has a thickness t 1 inside the steel pipe body 11 in the radial direction and a thickness t 2 outside, and the thickness t 2 is larger than the thickness t 1 (t 1 ⁇ . t 2 ).
- the second excavation bit 122B By forming the second excavation bit 122B with a tapered cross section as described above, the second portion that comes into contact with the earth and sand in advance when the steel pipe body 11 is rotated clockwise (CW) shown in FIG.
- the excavation bit 122B becomes thicker, and the resistance to wear of the second excavation bit 122B can be improved.
- only the second excavation bit 122B is formed with a tapered cross section, but both the first excavation bit 121 and the second excavation bit 122B may be formed with a tapered cross section. Only the excavation bit 121 of 1 may be formed with a tapered cross section.
- an inclination is formed on the tip surface of the first excavation bit 121 or the second excavation bit 122, and the first excavation bit 121 or the second excavation bit 122 is formed.
- 122 may be formed with a tapered cross section.
- FIG. 6 is a view of the steel pipe pile according to the second embodiment of the present invention as viewed from the side and the tip side.
- the steel pipe pile 20 includes a steel pipe main body 11 and a drilling bit 22 attached to an end surface 11E of the steel pipe main body 11.
- the excavation bit 22 includes a first excavation bit 221 and a second excavation bit 222.
- the first drill bit 221 by a height H 1 protrudes from the end surface 11E of the steel pipe body 11
- second drill bit 222 by a height H 2 protrudes from the end surface 11E of the steel pipe body 11
- Height H 2 is higher than height H 1 (H 1 ⁇ H 2 ).
- the first excavation bit 221 is attached at an angle ⁇ 1 (0 ⁇ 1 ⁇ 90 °) with respect to the circumferential tangent of the steel pipe body 11, and the second excavation bit 222 is the circumference of the steel pipe body 11. It is attached with an angle ⁇ 2 (0 ⁇ 2 ⁇ 90 °) with respect to the directional tangent, and the angle ⁇ 2 is larger than the angle ⁇ 1 ( ⁇ 1 ⁇ 2).
- the mounting angles ⁇ 1 and ⁇ 2 are the plate thickness center lines LC221 and L of the first drilling bit 221 and the second drilling bit 222, respectively, similarly to the mounting angles ⁇ described in the first embodiment.
- the length L of the first excavation bit 121 and the second excavation bit 122 along the attachment directions is the same.
- the attachment directions of the first excavation bit 221 and the second excavation bit 222 are directions tilted by the respective attachment angles ⁇ 1 and ⁇ 2 with respect to the circumferential tangent of the steel pipe main body 11.
- the steel pipe pile 20 is rotated counterclockwise (CCW) and clockwise (CW) shown in FIG. 6 in the present embodiment as in the first embodiment. ), The effect of suppressing or promoting the blockage of the soil inside the pipe can be obtained when excavating while rotating each of them.
- the attachment angle ⁇ 2 of the second excavation bit 222 is larger than the attachment angle ⁇ 1 of the first excavation bit 221.
- the first drilling bit 121 is centered on the pipe thickness on the outside of the steel pipe body 11.
- Write a distance D2 where the second drill bit 122 protrudes from the wall thickness center line L C11 in the radial direction of the steel pipe body 11 is longer than the distance D1 which projects from the line L C11 in the radial direction of the steel pipe body 11.
- the excavable region R2 of the second excavation bit 222 is expanded more than the excavable region R1 of the first excavation bit 221.
- the excavable areas R1 and R2 are annular areas in which each of the first excavation bit 221 and the second excavation bit 222 excavates earth and sand when the steel pipe pile 20 is rotated in the ground.
- both the first excavation bit 121 and the second excavation bit 122 project to both the outside and the inside of the steel pipe body 11, and the pipe thickness center line L of the steel pipe body 11 is centered in the mounting direction. Since it intersects with C11 , the distance from which the second excavation bit 122 protrudes is longer than the distance from which the first excavation bit 121 protrudes inside the steel pipe body 11, and excavation is possible than the excavable area R1. Region R2 is expanded. In another example, the excavable area may be extended only on the outside or the inside of the steel pipe body 11.
- the construction resistance is borne by the second excavation bit 222 that excavates the relatively expanded area, and the wear of the first excavation bit 221 whose construction resistance is reduced by that amount is suppressed. be able to.
- the wear of the first excavation bit 221 is also suppressed by making the protrusion height H 2 of the second excavation bit 222 higher than the protrusion height H 1 of the first excavation bit 221. Therefore, in the present embodiment, the wear of the first excavation bit 221 is suppressed more effectively, and the function of suppressing or promoting the blockage of the in-pipe soil by the excavation bit 22 is maintained even if the excavation is advanced in the layer having high ground strength. can do.
- an inclination in which the protruding height of the steel pipe body 11 increases from the inside to the outside in the radial direction on at least one of the tip surfaces 221E and 222E of the excavation bits 221A and 222A. May be formed.
- at least one of the excavation bits 221 and 222B may be formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body 11.
- FIG. 9 is a view of the steel pipe pile according to the third embodiment of the present invention as viewed from the side and the tip side.
- the steel pipe pile 30 includes a steel pipe main body 11 and a drilling bit 32 attached to an end surface 11E of the steel pipe main body 11.
- the excavation bit 32 includes a first excavation bit 321 and a second excavation bit 322.
- Height H 2 is higher than height H 1 (H 1 ⁇ H 2 ).
- the length along the attachment direction of the first excavation bit 321 is L1
- the length along the attachment direction of the second excavation bit 322 is L2
- the length L2 is the length. Is longer than L1 (L1 ⁇ L2).
- the first excavation bit 321 and the second excavation bit 322 are attached at the same attachment angle ⁇ (0 ⁇ ⁇ 90 °) with respect to the circumferential tangent of the steel pipe main body 11.
- the steel pipe pile 30 is rotated counterclockwise (CCW) and clockwise (CW) shown in FIG. 9 in the present embodiment as in the first embodiment.
- CCW counterclockwise
- CW clockwise
- the length L2 along the attachment direction of the second excavation bit 322 is longer than the length L1 along the attachment direction of the first excavation bit 321.
- a first drill bit 321 is the pipe thickness center line L C11 than the distance D1 which projects in the radial direction of the steel pipe body 11 from Trip distance D2 where the second drill bit 322 protrudes from the wall thickness center line L C11 in the radial direction of the steel pipe body 11 becomes longer.
- the excavable region R2 of the second excavation bit 322 is expanded more than the excavable region R1 of the first excavation bit 321.
- both the first excavation bit 321 and the second excavation bit 322 project to both the outside and the inside of the steel pipe body 11 in the radial direction, and the pipe thickness of the steel pipe body 11 is at the center of the mounting direction. Since it intersects the center line LC11 , the distance that the second excavation bit 322 protrudes is longer than the distance that the first excavation bit 321 protrudes inside the steel pipe main body 11, and the distance that the second excavation bit 322 protrudes is longer than the excavable area R1.
- the excavable area R2 is also expanded. In another example, the excavable area may be extended only on either the outside or the inside of the steel pipe body 11 in the radial direction.
- the construction resistance is borne by the second excavation bit 322 that excavates the relatively expanded area, and the wear of the first excavation bit 321 whose construction resistance is reduced by that amount is suppressed. be able to.
- the wear of the first excavation bit 321 is also suppressed by making the protrusion height H 2 of the second excavation bit 322 higher than the protrusion height H 1 of the first excavation bit 321. Therefore, in the present embodiment, the wear of the first excavation bit 321 is more effectively suppressed, and the function of suppressing or promoting the blockage of the in-pipe soil by the excavation bit 32 is maintained even when excavation is carried out in a layer having high ground strength. can do.
- the second and third embodiments of the present invention described above can be combined with each other. That is, in the embodiment of the present invention, in addition to making the protrusion height H 2 of the second excavation bit 322 higher than the protrusion height H 1 of the first excavation bit 321, the attachment of some excavation bits.
- the excavable area may be extended by making either the angle ⁇ or the length L along the mounting direction larger than the other drilling bits, or both the mounting angle ⁇ and the length L may be the other drilling bits.
- the excavable area may be expanded by making it larger than.
- the tip surface of at least one of the excavation bits may be inclined so that the protruding height increases from the inside to the outside in the radial direction of the steel pipe body, or at least one of the excavation bits is a steel pipe. It may be formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the main body.
- (Modification) 10 to 14 are views showing modified examples of the first to third embodiments described above. The modifications described below are applicable to each of the first to third embodiments, and to the embodiment in which the second embodiment and the third embodiment are combined.
- the excavation bit 42 includes a first excavation bit 421 and a second excavation bit 422.
- the protrusion height, the mounting angle ⁇ , or the length L are different between the first excavation bit 421 and the second excavation bit 422 as in the first to third embodiments described above.
- such a difference in shape between the first excavation bit and the second excavation bit is not necessarily shown.
- each drilling bit protrudes both outward and inside in the radial direction of the steel pipe body 11 and intersects the pipe thickness center line of the steel pipe body 11 at the center in the mounting direction. Similar to each of the above-described embodiments, the excavation bit may protrude only on either the outer side or the inner side in the radial direction of the main body 11.
- the arrangement pattern of the first excavation bit 421 and the second excavation bit 422 in the circumferential direction of the steel pipe main body 11 is different from each of the above embodiments. More specifically, in each of the above embodiments, the first excavation bit and the second excavation bit are alternately arranged alternately, whereas in the steel pipe pile 40 shown in FIG. 10, the first excavation bit and the second excavation bit are arranged alternately. The first excavation bit 421 and the second excavation bit 422 are alternately arranged every two. Further, in each of the above embodiments, the same number of the first excavation bit and the second excavation bit are arranged, whereas in the steel pipe pile 40 shown in FIG. 11, the first excavation bit 421 is set to 1. Two second excavation bits 422 are arranged for each arrangement, and therefore the number of second excavation bits 422 is greater than the number of first excavation bits 421.
- the drilling bit 42 includes a third drilling bit 423 and a fourth drilling bit 424 in addition to the first drilling bit 421 and the second drilling bit 422.
- the third drill bit 423 (only protrudes higher third height than the height H 2 from the other words, the end surface 11E of the steel pipe main body 11) further protruding height greater than the second drill bit 422.
- a third drill bit 423, the distance to further protrude from the second drill bit 422 is long (i.e., the distance from the wall thickness center line L C11 in the radial direction of the steel pipe body 11 of the steel pipe body 11 D2 (FIG.
- the excavation bit 6 may have an excavable area extended beyond the excavable area R2 of the second excavation bit 422) by projecting by a third distance longer than (see FIG. 9 and the like).
- the relationship between the third excavation bit 423 and the fourth excavation bit 424 is the same as the relationship between the second excavation bit 422 and the third excavation bit 423, and the fourth excavation bit 424 is, for example, the first. It may have an excavable area that is even higher than the excavation bit 423 of 3 and further expanded than the excavation bit 423 of the third excavation bit 423.
- the excavation bit is not limited to the two types of excavation bits, and may include three types or four or more types of excavation bits.
- excavation bits that bear the construction resistance in advance, such as the second excavation bit 422 and the third excavation bit 423 in the example shown in FIG.
- the excavation bit 42 including the first excavation bit 421 and the second excavation bit 422 is a curved plate-shaped excavation bit.
- the excavation bit 42 is curved so as to have a C shape when the steel pipe pile 40 is viewed from the tip side.
- the mounting angle ⁇ of the drill bit 42 at a position intersecting the wall thickness center line L C11 curved thickness center line L C42 steel pipe body 11 of the drill bit 42, the tangent of the thickness center line L C42 L T42 that the angle between the tangential line L T11 of pipe thickness center line L C11.
- the length L along the attachment direction of the excavation bit 42 is the length in the direction along the tangent line LT42 .
- the curved excavation bit 42 causes the steel pipe when the steel pipe pile 40 rotates counterclockwise (CCW). easily create flow F 1 of the sediment away from the main body 11 and the drill bit 42, also steel pipe pile 40 tends produces a flow F 2 of sediment towards the inside of the steel pipe body 11 when rotating clockwise (CW). By smoothing the flow of earth and sand, excavation using the steel pipe pile 40 becomes smoother.
- the excavation bit 42 is curved so as to have an S shape when the steel pipe pile 40 is viewed from the tip side.
- the mounting angle ⁇ of the drill bit 42 at a position where the curved thickness center line L C42 of the drill bit 42 intersects the wall thickness center line L C11 steel pipe body 11, the thickness center of the opposite ends of the drill bit 42 it is an angle formed by the tangent line L T11 linear L E42 and pipe thickness center line L C11 connecting the.
- the length L along the attachment direction of the excavation bit 42 is the length in the direction along the straight line LE 42 .
- the excavation bit protrudes both inside and outside the steel pipe body 11, or the excavation bit projects only inside the steel pipe body 11. It can be configured.
- the direction in which the excavation bit protrudes from the steel pipe body 11 may be different between the first excavation bit and the second excavation bit (and the third excavation bit and the fourth excavation bit).
- the drilling bit 12 pushes the earth and sand to the outside of the steel pipe body 11 in the first rotation direction (CCW) shown in FIG. 1 is carried out.
- the steel pipe pile 10 is placed in the second rotation direction (clockwise (CW) shown in FIG. 1) in which the excavation bit 12 takes in the earth and sand inside the steel pipe main body 11 until the tip of the steel pipe pile 10 reaches the stopping depth.
- the process of excavating while rotating is carried out.
- the predetermined depth is, for example, upward by a distance of about 1 to 5 times the diameter of the steel pipe main body 11 with respect to the stopping depth.
- the predetermined depth may be deeper than the depth of the support layer.
- the tip of the steel pipe pile 10 reaches the support layer at the time of stopping, and then the steel pipe pile 10 is rotated in the second rotation direction.
- the predetermined depth may be shallower than the depth of the support layer.
- the steel pipe pile 10 is excavated while rotating in the second rotation direction immediately before the tip of the steel pipe pile 10 reaches the support layer, and the tip of the steel pipe pile 10 is the support layer. Will be stopped after reaching.
- the step of excavating while rotating the steel pipe pile 10 in the first rotation direction and the step of excavating while rotating the steel pipe pile 10 in the second rotation direction may be alternately performed. .. That is, even before the tip of the steel pipe pile 10 reaches a predetermined depth, it is possible to excavate the steel pipe pile 10 while rotating it in the second rotation direction. Specifically, for example, when the rooting of the steel pipe pile 10 is not smooth, the steel pipe pile 10 is rooted while alternately switching the rotation direction, and finally the steel pipe pile 10 is set to the second rotation direction. It is conceivable to rotate and stop.
- the predetermined depth is the depth at which the steel pipe pile 10 is finally rotated in the first rotation direction, and may be, for example, a depth similar to the stopping depth.
- excavation (lowering of the tip) and retreat (rising of the tip) of the steel pipe pile 10 may be alternately performed as well as the rotation direction of the steel pipe pile 10.
- FIG. 15 is a graph showing the experimental results regarding the mounting angle of the excavation bit.
- excavation bits having a thickness of 6 mm, a length of 30 mm along the mounting direction, and a protrusion height of 12 mm from the end face of the steel pipe body were placed at equal intervals on a steel pipe body having a cross-sectional diameter of 101.6 mm and a pipe thickness of 5.7 mm.
- the mounting angle of the excavation bit is 0 ° (no mounting angle)
- 5 °, 15 °, 20 ° and 30 ° hit the simulated ground using Iitoyo silica sand No. 7 to the same depth.
- the bearing capacity of the installed steel pipe piles was compared.
- the load when the amount of sinking of the pile head (steel pipe head) is 10% of the pile diameter (cross-sectional diameter) is based on the "Road Bridge Specification / Explanation (IV Substructure)".
- (Ultimate bearing capacity) is the bearing capacity. Further, the bearing capacity is expressed by an increase rate when 1 is set when there is no mounting angle. As shown in the graph of FIG. 15, when there is a mounting angle (greater than 0 °), the bearing capacity is improved as compared with the case where there is no mounting angle. In particular, when the mounting angle was in the range of 5 ° to 15 °, a more remarkable improvement in bearing capacity was observed (about 1.25 times or more in the case of 0 °).
- the mounting angles ⁇ , ⁇ 1, ⁇ 2 of the excavation bit are set in the range of 5 ° or more and 15 ° or less (5 ° ⁇ ⁇ , ⁇ 1, ⁇ 2 ⁇ 15 °). Good. Since the bearing capacity is improved even outside the above range, the values of the mounting angles ⁇ , ⁇ 1 and ⁇ 2 are not limited to the above range.
- FIG. 16 is a diagram for explaining an experiment for verifying the wear suppressing effect of the excavation bit.
- excavation bits 121 and 122 having a thickness of 3.2 mm and a length of 30 mm along the mounting direction were equally spaced on a steel pipe body 11 having a cross-sectional diameter of 101.6 mm and a pipe thickness of 5.7 mm. I installed four.
- two of the excavation bits 121 have a protrusion height of 10 mm from the end face of the steel pipe body, and the remaining two excavation bits 122 have a protrusion height of 14 mm, and the excavation bit 121 and the excavation bit 122 and 122 were alternately arranged in the circumferential direction of the steel pipe main body 11.
- the mounting angle of the excavation bit is 10 °.
- the mounting angle of the excavation bit 121 is set to 10 °
- the mounting angle of the excavation bit 122 is set to 15 °.
- the excavation bits 121 and 122 both project to both the outside and the inside of the steel pipe body 11 and intersect the pipe thickness center line of the steel pipe body 11 at the center in the mounting direction. Note that FIG. 16 shows the conditions of the second embodiment. In the comparative example, four excavation bits were similarly attached, but the protrusion height was 12 mm and the attachment angle was 10 ° for all the excavation bits.
- FIG. 17 is a graph showing the results of the experiment shown in FIG. A mortar-shaped model ground was excavated at a construction depth of 500 mm with the steel pipe piles according to Examples 1, 2 and Comparative Examples as described with reference to FIG. As a result, as shown in the graph, when the volume residual ratio of each bit in the comparative example in which the mounting angle and the excavable area are the same for all the excavation bits is 1, two sets of excavations having different protrusion heights are excavated. In Example 1 in which the bits were arranged, the volume residual ratio of the excavation bit 121 having a low protrusion height was 4.85 times that of the comparative example.
- the volume residual ratio is the ratio of the volume of the excavation bit remaining after the construction to the volume of the excavation bit before the construction.
- Example 2 in which the excavable area is different in addition to the protruding heights of the two sets of excavating bits, the volume residual ratio of the excavating bits 121 having a low protruding height and a small excavable area is 5.23 times that of the comparative example. there were.
- the result is that the function of the excavation bit can be maintained against wear during excavation by making the projecting height different among multiple excavation bits, and the size of the excavable area in addition to the projecting height. It is shown that the effect is improved by making them different.
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Abstract
A steel pipe pile (10) that is provided with a steel pipe body (11), and plate-shaped drilling bits (12) attached to an end surface (11E) of the steel pipe body (11) at an angle (θ) with respect to a tangent to the circumferential direction of the steel pipe body and projecting in the axial direction of the steel pipe body (11), wherein the drilling bits (12) include: first drilling bits (121) that project from the end surface (11E) of the steel pipe body (11) in the axial direction of the steel pipe body (11) by an amount corresponding to a first height (H1), and second drilling bits (122) that project from the end surface (11E) of the steel pipe body (11) in the axial direction of the steel pipe body (11) by an amount corresponding to a second height (H2) greater than the first height (H1).
Description
本発明は、鋼管杭および鋼管杭の施工方法に関する。
The present invention relates to a steel pipe pile and a method for constructing a steel pipe pile.
鋼管杭の先端に取り付ける掘削ビットは、地盤を掘削する従来の効果のみならず、杭の回転方向に応じて掘削した土の動きを制御し、管内土の閉塞を抑制または促進する効果が期待される。例えば、特許文献1には、掘削ビットの長手方向の中心軸線と鋼管杭の外周との交点における接線方向とが角度を有しており、この角度によって掘削ビットの刃先が鋼管杭内側に向かって設けられる技術が記載されている。これによって、例えば、杭先端が支持層に到達する前には土砂を杭の外側に押し出して管内土の閉塞を抑制することによって掘削性を向上させ、杭先端が支持層に到達した後は杭の回転方向を逆にすることによって土砂を杭の内側に取り込み、管内土の閉塞を促進することによって高い支持力を獲得することができる。
The excavation bit attached to the tip of the steel pipe pile is expected to have the effect of controlling the movement of the excavated soil according to the rotation direction of the pile and suppressing or promoting the blockage of the soil inside the pipe, in addition to the conventional effect of excavating the ground. To. For example, in Patent Document 1, the central axis in the longitudinal direction of the excavation bit and the tangential direction at the intersection of the outer periphery of the steel pipe pile have an angle, and the cutting edge of the excavation bit is directed toward the inside of the steel pipe pile by this angle. The technology to be provided is described. As a result, for example, before the pile tip reaches the support layer, the earth and sand are pushed out to the outside of the pile to suppress the blockage of the soil in the pipe, thereby improving the excavability, and after the pile tip reaches the support layer, the pile. By reversing the direction of rotation of the pile, the earth and sand are taken into the inside of the pile, and high bearing capacity can be obtained by promoting the blockage of the soil inside the pipe.
しかしながら、鋼管杭の先端を支持層に貫入させる際には、地盤強度が高いために大きな施工抵抗(回転トルクや鉛直圧入力)が杭先端に取り付けられた掘削ビットに作用する結果、掘削ビットが摩耗することが想定される。それゆえ、例えば特許文献1に記載されたような掘削ビットの効果を最大化するためには、摩耗に対抗して掘削ビットの機能を維持できる構造とすることが望ましい。
However, when the tip of the steel pipe pile is penetrated into the support layer, a large construction resistance (rotational torque or vertical pressure input) acts on the excavation bit attached to the tip of the pile due to the high ground strength, resulting in the excavation bit. It is expected to wear. Therefore, in order to maximize the effect of the excavation bit as described in Patent Document 1, for example, it is desirable to have a structure capable of maintaining the function of the excavation bit against wear.
そこで、本発明は、掘削時の摩耗に対抗して掘削ビットの機能を維持することが可能な、新規かつ改良された鋼管杭および鋼管杭の施工方法を提供することを目的とする。
Therefore, an object of the present invention is to provide a new and improved method for constructing steel pipe piles and steel pipe piles, which can maintain the function of the excavation bit against wear during excavation.
[1]鋼管本体と、鋼管本体の端面に鋼管本体の周方向接線に対して角度をもって取り付けられ、鋼管本体の軸方向に突出する板状の掘削ビットとを備える鋼管杭であって、掘削ビットが、鋼管本体の端面から鋼管本体の軸方向に第1の高さだけ突出する第1の掘削ビットと、鋼管本体の端面から鋼管本体の軸方向に第1の高さよりも高い第2の高さだけ突出する第2の掘削ビットとを含む鋼管杭。
[2]第1の掘削ビットまたは第2の掘削ビットの少なくともいずれかの先端面に、鋼管本体の径方向の内側から外側に向かって突出高さが高くなる傾斜が形成される、[1]に記載の鋼管杭。
[3]第1の掘削ビットまたは第2の掘削ビットの少なくともいずれかが、鋼管本体の径方向の内側から外側に向かって厚くなるテーパー断面で形成される、[1]または[2]に記載の鋼管杭。
[4]掘削ビットが、鋼管本体の端面から鋼管本体の軸方向に第2の高さよりも高い第3の高さだけ突出する第3の掘削ビットをさらに含む、[1]から[3]のいずれか1項に記載の鋼管杭。
[5]掘削ビットは、鋼管杭を先端側から見たときにC字状またはS字状になるように湾曲した板状である、[1]から[4]のいずれか1項に記載の鋼管杭。
[6]掘削ビットは、鋼管本体の径方向の外側または内側の少なくともいずれかに突出し、第1の掘削ビットは、鋼管本体の管厚中心線から鋼管本体の径方向に第1の距離だけ突出することによって第1の掘削可能領域を有し、第2の掘削ビットは、鋼管本体の管厚中心線から鋼管本体の径方向に第1の距離よりも長い第2の距離だけ突出することによって、鋼管本体の径方向の外側または内側の少なくともいずれかで第1の掘削可能領域よりも拡張された第2の掘削可能領域を有する、[1]から[5]のいずれか1項に記載の鋼管杭。
[7]第1の掘削ビットは、鋼管本体の周方向接線に対して第1の角度をもって取り付けられ、第2の掘削ビットは、鋼管本体の周方向接線に対して第1の角度よりも大きい第2の角度をもって取り付けられる、[6]に記載の鋼管杭。
[8]第1の掘削ビットは、第1の掘削ビットの取り付け方向に沿って第1の長さを有し、第2の掘削ビットは、第2の掘削ビットの取り付け方向に沿って第1の長さよりも長い第2の長さを有する、[6]または[7]に記載の鋼管杭。
[9][1]から[8]のいずれか1項に記載された鋼管杭の施工方法であって、鋼管杭の先端が所定の深度に到達するまで、掘削ビットが土砂を鋼管本体の外側に押し出す第1の回転方向に鋼管杭を回転させながら掘削する工程と、鋼管杭の先端が打ち止め深さに到達するまで、掘削ビットが土砂を鋼管本体の内側に取り込む第2の回転方向に鋼管杭を回転させながら掘削する工程とを含む鋼管杭の施工方法。
[10]打ち止めの際に、鋼管杭の先端を支持層に到達させてから、鋼管杭を第2の回転方向に回転させる、[9]に記載の鋼管杭の施工方法。
[11]打ち止めの際に、鋼管杭の先端が支持層に到達する直前から、鋼管杭を第2の回転方向に回転させながら掘削し、鋼管杭の先端が支持層に到達してから打ち止める、[9]に記載の鋼管杭の施工方法。
[12]第1の回転方向に鋼管杭を回転させながら掘削する工程と、第2の回転方向に鋼管杭を回転させながら掘削する工程とが交互に実施される、[9]から[11]のいずれか1項に記載の鋼管杭の施工方法。 [1] A steel pipe pile provided with a steel pipe body and a plate-shaped excavation bit that is attached to the end surface of the steel pipe body at an angle with respect to the circumferential tangent line of the steel pipe body and projects in the axial direction of the steel pipe body. However, a first excavation bit projecting from the end face of the steel pipe body in the axial direction of the steel pipe body by the first height, and a second height higher than the first height in the axial direction of the steel pipe body from the end face of the steel pipe body. A steel pipe pile including a second drilling bit that protrudes so much.
[2] An inclination is formed on the tip surface of at least one of the first excavation bit and the second excavation bit so that the protrusion height increases from the inside to the outside in the radial direction of the steel pipe body [1]. Steel pipe pile described in.
[3] According to [1] or [2], at least one of the first excavation bit and the second excavation bit is formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body. Steel pipe pile.
[4] Of [1] to [3], the excavation bit further includes a third excavation bit protruding from the end face of the steel pipe body by a third height higher than the second height in the axial direction of the steel pipe body. The steel pipe pile according to any one item.
[5] The item according to any one of [1] to [4], wherein the excavation bit has a plate shape curved so as to have a C-shape or an S-shape when the steel pipe pile is viewed from the tip side. Steel pipe pile.
[6] The excavation bit protrudes at least either outside or inside in the radial direction of the steel pipe body, and the first excavation bit protrudes by the first distance in the radial direction of the steel pipe body from the pipe thickness center line of the steel pipe body. By doing so, the first excavable region is provided, and the second excavation bit projects from the pipe thickness center line of the steel pipe body by a second distance longer than the first distance in the radial direction of the steel pipe body. The item according to any one of [1] to [5], which has a second excavable area extended from the first excavable area at least either outside or inside the steel pipe body in the radial direction. Steel pipe pile.
[7] The first drilling bit is attached at a first angle with respect to the circumferential tangent of the steel pipe body, and the second drilling bit is larger than the first angle with respect to the circumferential tangent of the steel pipe body. The steel pipe pile according to [6], which is attached at a second angle.
[8] The first excavation bit has a first length along the attachment direction of the first excavation bit, and the second excavation bit is the first along the attachment direction of the second excavation bit. The steel pipe pile according to [6] or [7], which has a second length longer than the length of.
[9] The method for constructing a steel pipe pile according to any one of [1] to [8], in which the excavation bit removes earth and sand from the outside of the steel pipe body until the tip of the steel pipe pile reaches a predetermined depth. The process of excavating while rotating the steel pipe pile in the first rotation direction, and the steel pipe in the second rotation direction in which the excavation bit takes in the earth and sand inside the steel pipe body until the tip of the steel pipe pile reaches the stopping depth. Construction method of steel pipe pile including the process of excavating while rotating the pile.
[10] The method for constructing a steel pipe pile according to [9], wherein the tip of the steel pipe pile reaches the support layer at the time of stopping, and then the steel pipe pile is rotated in the second rotation direction.
[11] At the time of stopping, excavation is performed while rotating the steel pipe pile in the second rotation direction immediately before the tip of the steel pipe pile reaches the support layer, and the steel pipe pile is stopped after reaching the support layer. , [9]. The method for constructing a steel pipe pile.
[12] The steps of excavating while rotating the steel pipe pile in the first rotation direction and the step of excavating while rotating the steel pipe pile in the second rotation direction are alternately carried out [9] to [11]. The method for constructing a steel pipe pile according to any one of the above items.
[2]第1の掘削ビットまたは第2の掘削ビットの少なくともいずれかの先端面に、鋼管本体の径方向の内側から外側に向かって突出高さが高くなる傾斜が形成される、[1]に記載の鋼管杭。
[3]第1の掘削ビットまたは第2の掘削ビットの少なくともいずれかが、鋼管本体の径方向の内側から外側に向かって厚くなるテーパー断面で形成される、[1]または[2]に記載の鋼管杭。
[4]掘削ビットが、鋼管本体の端面から鋼管本体の軸方向に第2の高さよりも高い第3の高さだけ突出する第3の掘削ビットをさらに含む、[1]から[3]のいずれか1項に記載の鋼管杭。
[5]掘削ビットは、鋼管杭を先端側から見たときにC字状またはS字状になるように湾曲した板状である、[1]から[4]のいずれか1項に記載の鋼管杭。
[6]掘削ビットは、鋼管本体の径方向の外側または内側の少なくともいずれかに突出し、第1の掘削ビットは、鋼管本体の管厚中心線から鋼管本体の径方向に第1の距離だけ突出することによって第1の掘削可能領域を有し、第2の掘削ビットは、鋼管本体の管厚中心線から鋼管本体の径方向に第1の距離よりも長い第2の距離だけ突出することによって、鋼管本体の径方向の外側または内側の少なくともいずれかで第1の掘削可能領域よりも拡張された第2の掘削可能領域を有する、[1]から[5]のいずれか1項に記載の鋼管杭。
[7]第1の掘削ビットは、鋼管本体の周方向接線に対して第1の角度をもって取り付けられ、第2の掘削ビットは、鋼管本体の周方向接線に対して第1の角度よりも大きい第2の角度をもって取り付けられる、[6]に記載の鋼管杭。
[8]第1の掘削ビットは、第1の掘削ビットの取り付け方向に沿って第1の長さを有し、第2の掘削ビットは、第2の掘削ビットの取り付け方向に沿って第1の長さよりも長い第2の長さを有する、[6]または[7]に記載の鋼管杭。
[9][1]から[8]のいずれか1項に記載された鋼管杭の施工方法であって、鋼管杭の先端が所定の深度に到達するまで、掘削ビットが土砂を鋼管本体の外側に押し出す第1の回転方向に鋼管杭を回転させながら掘削する工程と、鋼管杭の先端が打ち止め深さに到達するまで、掘削ビットが土砂を鋼管本体の内側に取り込む第2の回転方向に鋼管杭を回転させながら掘削する工程とを含む鋼管杭の施工方法。
[10]打ち止めの際に、鋼管杭の先端を支持層に到達させてから、鋼管杭を第2の回転方向に回転させる、[9]に記載の鋼管杭の施工方法。
[11]打ち止めの際に、鋼管杭の先端が支持層に到達する直前から、鋼管杭を第2の回転方向に回転させながら掘削し、鋼管杭の先端が支持層に到達してから打ち止める、[9]に記載の鋼管杭の施工方法。
[12]第1の回転方向に鋼管杭を回転させながら掘削する工程と、第2の回転方向に鋼管杭を回転させながら掘削する工程とが交互に実施される、[9]から[11]のいずれか1項に記載の鋼管杭の施工方法。 [1] A steel pipe pile provided with a steel pipe body and a plate-shaped excavation bit that is attached to the end surface of the steel pipe body at an angle with respect to the circumferential tangent line of the steel pipe body and projects in the axial direction of the steel pipe body. However, a first excavation bit projecting from the end face of the steel pipe body in the axial direction of the steel pipe body by the first height, and a second height higher than the first height in the axial direction of the steel pipe body from the end face of the steel pipe body. A steel pipe pile including a second drilling bit that protrudes so much.
[2] An inclination is formed on the tip surface of at least one of the first excavation bit and the second excavation bit so that the protrusion height increases from the inside to the outside in the radial direction of the steel pipe body [1]. Steel pipe pile described in.
[3] According to [1] or [2], at least one of the first excavation bit and the second excavation bit is formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body. Steel pipe pile.
[4] Of [1] to [3], the excavation bit further includes a third excavation bit protruding from the end face of the steel pipe body by a third height higher than the second height in the axial direction of the steel pipe body. The steel pipe pile according to any one item.
[5] The item according to any one of [1] to [4], wherein the excavation bit has a plate shape curved so as to have a C-shape or an S-shape when the steel pipe pile is viewed from the tip side. Steel pipe pile.
[6] The excavation bit protrudes at least either outside or inside in the radial direction of the steel pipe body, and the first excavation bit protrudes by the first distance in the radial direction of the steel pipe body from the pipe thickness center line of the steel pipe body. By doing so, the first excavable region is provided, and the second excavation bit projects from the pipe thickness center line of the steel pipe body by a second distance longer than the first distance in the radial direction of the steel pipe body. The item according to any one of [1] to [5], which has a second excavable area extended from the first excavable area at least either outside or inside the steel pipe body in the radial direction. Steel pipe pile.
[7] The first drilling bit is attached at a first angle with respect to the circumferential tangent of the steel pipe body, and the second drilling bit is larger than the first angle with respect to the circumferential tangent of the steel pipe body. The steel pipe pile according to [6], which is attached at a second angle.
[8] The first excavation bit has a first length along the attachment direction of the first excavation bit, and the second excavation bit is the first along the attachment direction of the second excavation bit. The steel pipe pile according to [6] or [7], which has a second length longer than the length of.
[9] The method for constructing a steel pipe pile according to any one of [1] to [8], in which the excavation bit removes earth and sand from the outside of the steel pipe body until the tip of the steel pipe pile reaches a predetermined depth. The process of excavating while rotating the steel pipe pile in the first rotation direction, and the steel pipe in the second rotation direction in which the excavation bit takes in the earth and sand inside the steel pipe body until the tip of the steel pipe pile reaches the stopping depth. Construction method of steel pipe pile including the process of excavating while rotating the pile.
[10] The method for constructing a steel pipe pile according to [9], wherein the tip of the steel pipe pile reaches the support layer at the time of stopping, and then the steel pipe pile is rotated in the second rotation direction.
[11] At the time of stopping, excavation is performed while rotating the steel pipe pile in the second rotation direction immediately before the tip of the steel pipe pile reaches the support layer, and the steel pipe pile is stopped after reaching the support layer. , [9]. The method for constructing a steel pipe pile.
[12] The steps of excavating while rotating the steel pipe pile in the first rotation direction and the step of excavating while rotating the steel pipe pile in the second rotation direction are alternately carried out [9] to [11]. The method for constructing a steel pipe pile according to any one of the above items.
上記の構成によれば、突出高さがより高い第2の掘削ビットに施工抵抗を負担させ、その分だけ第1の掘削ビットの摩耗を抑制することができる。従って、掘削時の摩耗に対抗して掘削ビットの機能を維持することができる。
According to the above configuration, the construction resistance is borne by the second excavation bit having a higher protrusion height, and the wear of the first excavation bit can be suppressed by that amount. Therefore, the function of the excavation bit can be maintained against the wear during excavation.
以下に添付図面を参照しながら、本発明の好適な実施形態について詳細に説明する。なお、本明細書および図面において、実質的に同一の機能構成を有する構成要素については、同一の符号を付することにより重複説明を省略する。
A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.
(第1の実施形態)
図1は、本発明の第1の実施形態に係る鋼管杭を側方および先端側から見た図である。図1に示されるように、鋼管杭10は、鋼管本体11と、鋼管本体11の端面11Eに取り付けられ、鋼管本体11の軸方向に突出する掘削ビット12とを含む。掘削ビット12は、第1の掘削ビット121および第2の掘削ビット122を含む。本実施形態において、第1の掘削ビット121および第2の掘削ビット122は、いずれも鋼管本体11の周方向接線に対して角度θ(0<θ<90°)をもって取り付けられている。ここで、角度θは、板状の掘削ビット12の板厚中心線LC12が鋼管本体11の管厚中心線LC11に交わる位置において、板厚中心線LC12と管厚中心線LC11の接線LT11(鋼管本体11の周方向接線)とがなす角度である。以下では、角度θを掘削ビット12の取り付け角度ともいう。第1の掘削ビット121および第2の掘削ビット122の取り付け方向は、鋼管本体11の周方向接線に対してそれぞれの取り付け角度θ1,θ2だけ傾いた方向である。 (First Embodiment)
FIG. 1 is a view of a steel pipe pile according to a first embodiment of the present invention as viewed from the side and the tip side. As shown in FIG. 1, thesteel pipe pile 10 includes a steel pipe main body 11 and a drilling bit 12 attached to an end surface 11E of the steel pipe main body 11 and protruding in the axial direction of the steel pipe main body 11. The excavation bit 12 includes a first excavation bit 121 and a second excavation bit 122. In the present embodiment, both the first excavation bit 121 and the second excavation bit 122 are attached at an angle θ (0 <θ <90 °) with respect to the circumferential tangent of the steel pipe body 11. Here, the angle theta, the thickness center line L C12 plate-like drill bit 12 is at a position intersecting the wall thickness center line L C11 steel pipe body 11, the thickness center line L C12 and the pipe thickness center line L C11 This is the angle formed by the tangent line LT11 (the circumferential tangent line of the steel pipe body 11). Hereinafter, the angle θ is also referred to as the mounting angle of the excavation bit 12. The attachment directions of the first excavation bit 121 and the second excavation bit 122 are directions tilted by the respective attachment angles θ1 and θ2 with respect to the circumferential tangent of the steel pipe main body 11.
図1は、本発明の第1の実施形態に係る鋼管杭を側方および先端側から見た図である。図1に示されるように、鋼管杭10は、鋼管本体11と、鋼管本体11の端面11Eに取り付けられ、鋼管本体11の軸方向に突出する掘削ビット12とを含む。掘削ビット12は、第1の掘削ビット121および第2の掘削ビット122を含む。本実施形態において、第1の掘削ビット121および第2の掘削ビット122は、いずれも鋼管本体11の周方向接線に対して角度θ(0<θ<90°)をもって取り付けられている。ここで、角度θは、板状の掘削ビット12の板厚中心線LC12が鋼管本体11の管厚中心線LC11に交わる位置において、板厚中心線LC12と管厚中心線LC11の接線LT11(鋼管本体11の周方向接線)とがなす角度である。以下では、角度θを掘削ビット12の取り付け角度ともいう。第1の掘削ビット121および第2の掘削ビット122の取り付け方向は、鋼管本体11の周方向接線に対してそれぞれの取り付け角度θ1,θ2だけ傾いた方向である。 (First Embodiment)
FIG. 1 is a view of a steel pipe pile according to a first embodiment of the present invention as viewed from the side and the tip side. As shown in FIG. 1, the
本実施形態では、掘削ビット12が取り付け角度θを有することによって、例えば鋼管杭10を用いた掘削時において杭先端が所定の深さに到達するまでは鋼管杭10を図1に示す反時計回り(CCW)に回転させながら掘削して土砂を鋼管本体11の外側に押し出し、管内土の閉塞を抑制することができる。また、杭先端が打ち止め深さに到達するまでは鋼管杭10を図1に示す時計回り(CW)に回転させながら掘削して土砂を鋼管本体11の内側に取り込み、管内土の閉塞を促進することによって高い支持力を獲得することができる。なお、掘削ビット12は、鋼管本体11の径方向の内側および外側の両方にエッジを有し、これによって上記のように鋼管本体11の回転方向を反転させて掘削することが可能になる。
In the present embodiment, since the excavation bit 12 has the attachment angle θ, the steel pipe pile 10 is rotated counterclockwise as shown in FIG. 1 until the tip of the pile reaches a predetermined depth, for example, during excavation using the steel pipe pile 10. It is possible to excavate while rotating to (CCW) and push the earth and sand to the outside of the steel pipe main body 11 to suppress the blockage of the soil inside the pipe. Further, the steel pipe pile 10 is excavated while rotating clockwise (CW) shown in FIG. 1 until the tip of the pile reaches the stopping depth, and the earth and sand are taken into the inside of the steel pipe main body 11 to promote the blockage of the soil inside the pipe. By doing so, high support can be obtained. The excavation bit 12 has edges both inside and outside in the radial direction of the steel pipe body 11, which enables excavation by reversing the rotation direction of the steel pipe body 11 as described above.
なお、本実施形態では、第1の掘削ビット121および第2の掘削ビット122がいずれも鋼管本体11の径方向の外側および内側の両方に突出し、かつ取り付け方向の中心で鋼管本体11の管厚中心線LC11に交差する。他の実施形態では、図2および図3に示す例のように、鋼管本体11の径方向の外側または内側のいずれか一方だけに掘削ビットが突出していてもよい。
In the present embodiment, both the first excavation bit 121 and the second excavation bit 122 project to both the outside and the inside of the steel pipe body 11 in the radial direction, and the pipe thickness of the steel pipe body 11 is centered in the mounting direction. Crosses the center line LC11 . In another embodiment, as in the example shown in FIGS. 2 and 3, the excavation bit may protrude only to either the outside or the inside in the radial direction of the steel pipe body 11.
さらに、本実施形態において、掘削ビット12のうち第1の掘削ビット121は鋼管本体11の端面11Eから鋼管本体11の軸方向に高さH1だけ突出し、第2の掘削ビット122は鋼管本体11の端面11Eから鋼管本体11の軸方向に高さH2だけ突出し、高さH2は高さH1よりも高い(H1<H2)。例えば支持層のように地盤強度が高い層を掘削する場合、大きな施工抵抗が掘削ビット12に作用することによって掘削ビット12が摩耗することが想定される。これに対して、上記のように第2の掘削ビット122の突出高さH2を第1の掘削ビット121の突出高さH1よりも高くすることによって、掘削において先行する第2の掘削ビット122に施工抵抗を負担させ、その分だけ施工抵抗が軽減される第1の掘削ビット121の摩耗を抑制することができる。第1の掘削ビット121の摩耗が顕著になるのは、例えば第2の掘削ビット122の突出高さが摩耗によって第1の掘削ビット121と同程度になった後であるため、施工終了まで第1の掘削ビット121の摩耗が顕著にならない場合もあり得る。このように、第1の掘削ビット121の摩耗が抑制されることによって、地盤強度が高い層で掘削を進めても、上述したような掘削ビット12による管内土の閉塞の抑制または促進の機能を維持することができる。
Further, in the present embodiment, the first drill bit 121 by a height H 1 protrudes from the end surface 11E of the steel pipe body 11 in the axial direction of the steel pipe body 11 of the drill bit 12, the second drill bit 122 steel body 11 The height H 2 protrudes from the end surface 11E of the steel pipe body 11 in the axial direction by the height H 2, and the height H 2 is higher than the height H 1 (H 1 <H 2 ). For example, when excavating a layer having high ground strength such as a support layer, it is assumed that the excavation bit 12 is worn due to a large construction resistance acting on the excavation bit 12. On the other hand, by making the protrusion height H 2 of the second excavation bit 122 higher than the protrusion height H 1 of the first excavation bit 121 as described above, the second excavation bit that precedes in the excavation It is possible to make the 122 bear the construction resistance and suppress the wear of the first excavation bit 121 whose construction resistance is reduced by that amount. The wear of the first excavation bit 121 becomes remarkable, for example, after the protruding height of the second excavation bit 122 becomes about the same as that of the first excavation bit 121 due to the wear. In some cases, the wear of the excavation bit 121 of 1 is not remarkable. By suppressing the wear of the first excavation bit 121 in this way, even if excavation is carried out in a layer having high ground strength, the function of suppressing or promoting the blockage of the in-pipe soil by the excavation bit 12 as described above can be achieved. Can be maintained.
なお、鋼管本体11への掘削ビット12の取り付け方法は、例えば溶接であってもよいし、ねじ止めなどの機械的な接合手段によるものであってもよい。また、図1に示された例において鋼管本体11の端面11Eと掘削ビット12の上端面とは一致しているが、例えば端面11Eに形成された溝または切り込みに掘削ビット12を嵌合させた上で接合したり、掘削ビット12の上端面に形成された溝または切り込みに鋼管本体11の端面11Eを含む端部を嵌合させた上で接合したり、端面11Eおよび掘削ビット12の上端面の両方に溝または切り込みを形成してこれらの溝または切り込みを互いに嵌合させた上で接合したりすることが可能である。この場合、鋼管本体11の端面11Eと掘削ビット12の上端面とは必ずしも一致しない。以下で説明する他の例についても同様である。
The method of attaching the excavation bit 12 to the steel pipe body 11 may be, for example, welding or mechanical joining means such as screwing. Further, in the example shown in FIG. 1, the end surface 11E of the steel pipe body 11 and the upper end surface of the excavation bit 12 coincide with each other, but the excavation bit 12 is fitted into, for example, a groove or a notch formed in the end surface 11E. It can be joined above, or it can be joined after fitting the end of the steel pipe body 11 including the end face 11E into the groove or notch formed in the upper end surface of the excavation bit 12, or the end face 11E and the upper end surface of the excavation bit 12. It is possible to form grooves or notches in both of them so that these grooves or notches fit together and then join. In this case, the end surface 11E of the steel pipe body 11 and the upper end surface of the excavation bit 12 do not always match. The same applies to the other examples described below.
図4は、本発明の第1の実施形態に係る鋼管杭の別の例を示す図である。図4に示された例では、上記で図1を参照して説明した例と同様に掘削ビット12に含まれる第1の掘削ビット121Aおよび第2の掘削ビット122Aが取り付け角度θを有し、また第2の掘削ビット122Aの突出高さH2が第1の掘削ビット121Aの突出高さH1よりも高い。加えて、図示された例では、第1の掘削ビット121Aおよび第2の掘削ビット122Aの先端面121E,122E、すなわち鋼管本体11の端面11Eとは反対側の端面に、鋼管本体11の径方向の内側から外側に向かって突出高さが高くなる傾斜が形成されている。
FIG. 4 is a diagram showing another example of the steel pipe pile according to the first embodiment of the present invention. In the example shown in FIG. 4, the first excavation bit 121A and the second excavation bit 122A included in the excavation bit 12 have a mounting angle θ as in the example described with reference to FIG. 1 above. Further, the protrusion height H 2 of the second excavation bit 122A is higher than the protrusion height H 1 of the first excavation bit 121A. In addition, in the illustrated example, the tip surfaces 121E and 122E of the first excavation bit 121A and the second excavation bit 122A, that is, the end surface of the steel pipe body 11 opposite to the end surface 11E, in the radial direction of the steel pipe body 11. A slope is formed in which the protruding height increases from the inside to the outside of the pipe.
上記のように第1の掘削ビット121Aおよび第2の掘削ビット122Aの先端面121E,122Eに傾斜を形成することによって、鋼管本体11を図4に示す時計回り(CW)に回転させたときに先行して土砂に接触する部分で第1の掘削ビット121Aおよび第2の掘削ビット122Aの突出高さがより高くなり、第1の掘削ビット121Aおよび第2の掘削ビット122Aの摩耗に対する抵抗力を向上させることができる。なお、第1の掘削ビット121Aおよび第2の掘削ビット122Aの突出高さH1,H2は、例えば図示されたように端面11Eから傾斜した先端面121E,122Eの最も高い位置までの高さとして定義することができる。また、図示された例では第1の掘削ビット121Aおよび第2の掘削ビット122Aの先端面121E,122Eの両方に傾斜が形成されているが、いずれか一方の先端面のみに傾斜が形成されてもよい。
When the steel pipe body 11 is rotated clockwise (CW) shown in FIG. 4 by forming an inclination on the tip surfaces 121E and 122E of the first excavation bit 121A and the second excavation bit 122A as described above. The protrusion height of the first excavation bit 121A and the second excavation bit 122A becomes higher in the portion that comes into contact with the earth and sand in advance, and the resistance to wear of the first excavation bit 121A and the second excavation bit 122A is increased. Can be improved. The protruding heights H 1 and H 2 of the first excavation bit 121A and the second excavation bit 122A are, for example, the heights from the end surface 11E to the highest position of the inclined tip surfaces 121E and 122E as shown in the figure. Can be defined as. Further, in the illustrated example, both the tip surfaces 121E and 122E of the first excavation bit 121A and the second excavation bit 122A are inclined, but only one of the tip surfaces is inclined. May be good.
図5は、本発明の第1の実施形態に係る鋼管杭のさらに別の例を示す図である。図5に示された例では、上記で図1を参照して説明した例と同様に掘削ビット12に含まれる第1の掘削ビット121および第2の掘削ビット122Bが取り付け角度θを有し、また第2の掘削ビット122Bの突出高さH2が第1の掘削ビット121の突出高さH1よりも高い。加えて、図示された例では、第2の掘削ビット122Bが、鋼管本体11の径方向の内側から外側に向かって厚くなるテーパー断面で形成されている。具体的には、第2の掘削ビット122Bは鋼管本体11の径方向内側において厚さt1、外側で厚さt2であり、厚さt2は厚さt1よりも大きい(t1<t2)。
FIG. 5 is a diagram showing still another example of the steel pipe pile according to the first embodiment of the present invention. In the example shown in FIG. 5, the first excavation bit 121 and the second excavation bit 122B included in the excavation bit 12 have a mounting angle θ as in the example described with reference to FIG. 1 above. Further, the protrusion height H 2 of the second excavation bit 122B is higher than the protrusion height H 1 of the first excavation bit 121. In addition, in the illustrated example, the second excavation bit 122B is formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body 11. Specifically, the second excavation bit 122B has a thickness t 1 inside the steel pipe body 11 in the radial direction and a thickness t 2 outside, and the thickness t 2 is larger than the thickness t 1 (t 1 <. t 2 ).
上記のように第2の掘削ビット122Bをテーパー断面で形成することによって、鋼管本体11を図5に示す時計回り(CW)で回転させたときに先行して土砂に接触する部分で第2の掘削ビット122Bがより厚くなり、第2の掘削ビット122Bの摩耗に対する抵抗力を向上させることができる。なお、図示された例では第2の掘削ビット122Bのみがテーパー断面で形成されているが、第1の掘削ビット121および第2の掘削ビット122Bの両方がテーパー断面で形成されてもよく、第1の掘削ビット121のみがテーパー断面で形成されてもよい。また、図5の例と図4の例とを組み合わせ、第1の掘削ビット121または第2の掘削ビット122の先端面に傾斜を形成するとともに、第1の掘削ビット121または第2の掘削ビット122をテーパー断面で形成してもよい。
By forming the second excavation bit 122B with a tapered cross section as described above, the second portion that comes into contact with the earth and sand in advance when the steel pipe body 11 is rotated clockwise (CW) shown in FIG. The excavation bit 122B becomes thicker, and the resistance to wear of the second excavation bit 122B can be improved. In the illustrated example, only the second excavation bit 122B is formed with a tapered cross section, but both the first excavation bit 121 and the second excavation bit 122B may be formed with a tapered cross section. Only the excavation bit 121 of 1 may be formed with a tapered cross section. Further, by combining the example of FIG. 5 and the example of FIG. 4, an inclination is formed on the tip surface of the first excavation bit 121 or the second excavation bit 122, and the first excavation bit 121 or the second excavation bit 122 is formed. 122 may be formed with a tapered cross section.
(第2の実施形態)
図6は、本発明の第2の実施形態に係る鋼管杭を側方および先端側から見た図である。図6に示されるように、鋼管杭20は、鋼管本体11と、鋼管本体11の端面11Eに取り付けられる掘削ビット22とを含む。掘削ビット22は、第1の掘削ビット221および第2の掘削ビット222を含む。第1の実施形態と同様に、第1の掘削ビット221は鋼管本体11の端面11Eから高さH1だけ突出し、第2の掘削ビット222は鋼管本体11の端面11Eから高さH2だけ突出し、高さH2は高さH1よりも高い(H1<H2)。さらに、本実施形態において、第1の掘削ビット221は鋼管本体11の周方向接線に対して角度θ1(0<θ1<90°)をもって取り付けられ、第2の掘削ビット222は鋼管本体11の周方向接線に対して角度θ2(0<θ2<90°)をもって取り付けられ、角度θ2は角度θ1よりも大きい(θ1<θ2)。ここで、取り付け角度θ1,θ2は、第1の実施形態で説明された取り付け角度θと同様に、第1の掘削ビット221および第2の掘削ビット222のそれぞれの板厚中心線LC221,LC222と鋼管本体11の管厚中心線LC11の接線LT11、すなわち鋼管本体11の周方向接線とがなす角度である。一方、本実施形態において、第1の掘削ビット121および第2の掘削ビット122のそれぞれの取り付け方向に沿った長さLは同じである。第1の掘削ビット221および第2の掘削ビット222の取り付け方向は、鋼管本体11の周方向接線に対してそれぞれの取り付け角度θ1,θ2だけ傾いた方向である。 (Second Embodiment)
FIG. 6 is a view of the steel pipe pile according to the second embodiment of the present invention as viewed from the side and the tip side. As shown in FIG. 6, thesteel pipe pile 20 includes a steel pipe main body 11 and a drilling bit 22 attached to an end surface 11E of the steel pipe main body 11. The excavation bit 22 includes a first excavation bit 221 and a second excavation bit 222. Like the first embodiment, the first drill bit 221 by a height H 1 protrudes from the end surface 11E of the steel pipe body 11, second drill bit 222 by a height H 2 protrudes from the end surface 11E of the steel pipe body 11 , Height H 2 is higher than height H 1 (H 1 <H 2 ). Further, in the present embodiment, the first excavation bit 221 is attached at an angle θ1 (0 <θ1 <90 °) with respect to the circumferential tangent of the steel pipe body 11, and the second excavation bit 222 is the circumference of the steel pipe body 11. It is attached with an angle θ2 (0 <θ2 <90 °) with respect to the directional tangent, and the angle θ2 is larger than the angle θ1 (θ1 <θ2). Here, the mounting angles θ1 and θ2 are the plate thickness center lines LC221 and L of the first drilling bit 221 and the second drilling bit 222, respectively, similarly to the mounting angles θ described in the first embodiment. C222 and the tangent L T11 of pipe thickness center line L C11 steel pipe body 11, that is, the angle between the circumferential tangent of the steel pipe body 11. On the other hand, in the present embodiment, the length L of the first excavation bit 121 and the second excavation bit 122 along the attachment directions is the same. The attachment directions of the first excavation bit 221 and the second excavation bit 222 are directions tilted by the respective attachment angles θ1 and θ2 with respect to the circumferential tangent of the steel pipe main body 11.
図6は、本発明の第2の実施形態に係る鋼管杭を側方および先端側から見た図である。図6に示されるように、鋼管杭20は、鋼管本体11と、鋼管本体11の端面11Eに取り付けられる掘削ビット22とを含む。掘削ビット22は、第1の掘削ビット221および第2の掘削ビット222を含む。第1の実施形態と同様に、第1の掘削ビット221は鋼管本体11の端面11Eから高さH1だけ突出し、第2の掘削ビット222は鋼管本体11の端面11Eから高さH2だけ突出し、高さH2は高さH1よりも高い(H1<H2)。さらに、本実施形態において、第1の掘削ビット221は鋼管本体11の周方向接線に対して角度θ1(0<θ1<90°)をもって取り付けられ、第2の掘削ビット222は鋼管本体11の周方向接線に対して角度θ2(0<θ2<90°)をもって取り付けられ、角度θ2は角度θ1よりも大きい(θ1<θ2)。ここで、取り付け角度θ1,θ2は、第1の実施形態で説明された取り付け角度θと同様に、第1の掘削ビット221および第2の掘削ビット222のそれぞれの板厚中心線LC221,LC222と鋼管本体11の管厚中心線LC11の接線LT11、すなわち鋼管本体11の周方向接線とがなす角度である。一方、本実施形態において、第1の掘削ビット121および第2の掘削ビット122のそれぞれの取り付け方向に沿った長さLは同じである。第1の掘削ビット221および第2の掘削ビット222の取り付け方向は、鋼管本体11の周方向接線に対してそれぞれの取り付け角度θ1,θ2だけ傾いた方向である。 (Second Embodiment)
FIG. 6 is a view of the steel pipe pile according to the second embodiment of the present invention as viewed from the side and the tip side. As shown in FIG. 6, the
上記のように掘削ビット22が取り付け角度θ1,θ2を有することによって、本実施形態でも第1の実施形態と同様に、鋼管杭20を図6に示す反時計回り(CCW)および時計回り(CW)のそれぞれに回転させながら掘削するときに、管内土の閉塞を抑制または促進する効果が得られる。
Since the excavation bit 22 has the mounting angles θ1 and θ2 as described above, the steel pipe pile 20 is rotated counterclockwise (CCW) and clockwise (CW) shown in FIG. 6 in the present embodiment as in the first embodiment. ), The effect of suppressing or promoting the blockage of the soil inside the pipe can be obtained when excavating while rotating each of them.
加えて、本実施形態では、第2の掘削ビット222の取り付け角度θ2が第1の掘削ビット221の取り付け角度θ1よりも大きい。これによって、第1の掘削ビット221および第2の掘削ビット222の取り付け方向に沿った長さLが同じであっても、例えば鋼管本体11の外側について、第1の掘削ビット121が管厚中心線LC11から鋼管本体11の径方向に突出する距離D1よりも第2の掘削ビット122が管厚中心線LC11から鋼管本体11の径方向に突出する距離D2の方が長くなる。これによって、鋼管本体11の外側で、第1の掘削ビット221の掘削可能領域R1よりも第2の掘削ビット222の掘削可能領域R2が拡張される。ここで、掘削可能領域R1,R2は、地中で鋼管杭20を回転させたときに第1の掘削ビット221および第2の掘削ビット222のそれぞれが土砂を掘削する円環状の領域である。例えば、鋼管本体11の外側について、図6に示すように掘削可能領域R1の半径をr1、掘削可能領域R2の半径をr2とした場合、r2/r1=1.2程度になるように取り付け角度θ1,θ2を設定してもよい。
In addition, in the present embodiment, the attachment angle θ2 of the second excavation bit 222 is larger than the attachment angle θ1 of the first excavation bit 221. As a result, even if the length L of the first drilling bit 221 and the second drilling bit 222 along the mounting direction is the same, for example, the first drilling bit 121 is centered on the pipe thickness on the outside of the steel pipe body 11. Write a distance D2 where the second drill bit 122 protrudes from the wall thickness center line L C11 in the radial direction of the steel pipe body 11 is longer than the distance D1 which projects from the line L C11 in the radial direction of the steel pipe body 11. As a result, on the outside of the steel pipe body 11, the excavable region R2 of the second excavation bit 222 is expanded more than the excavable region R1 of the first excavation bit 221. Here, the excavable areas R1 and R2 are annular areas in which each of the first excavation bit 221 and the second excavation bit 222 excavates earth and sand when the steel pipe pile 20 is rotated in the ground. For example, regarding the outside of the steel pipe body 11, when the radius of the excavable region R1 is r1 and the radius of the excavable region R2 is r2 as shown in FIG. 6, the mounting angle is such that r2 / r1 = 1.2. θ1 and θ2 may be set.
なお、本実施形態では、第1の掘削ビット121および第2の掘削ビット122がいずれも鋼管本体11の外側および内側の両方に突出し、かつ取り付け方向の中心で鋼管本体11の管厚中心線LC11に交差するため、鋼管本体11の内側でも同様に、第1の掘削ビット121が突出する距離よりも第2の掘削ビット122が突出する距離の方が長く、掘削可能領域R1よりも掘削可能領域R2が拡張される。他の例では、鋼管本体11の外側または内側のいずれか一方だけで掘削可能領域が拡張されてもよい。
In the present embodiment, both the first excavation bit 121 and the second excavation bit 122 project to both the outside and the inside of the steel pipe body 11, and the pipe thickness center line L of the steel pipe body 11 is centered in the mounting direction. Since it intersects with C11 , the distance from which the second excavation bit 122 protrudes is longer than the distance from which the first excavation bit 121 protrudes inside the steel pipe body 11, and excavation is possible than the excavable area R1. Region R2 is expanded. In another example, the excavable area may be extended only on the outside or the inside of the steel pipe body 11.
上記のような構成によって、相対的に拡張された領域を掘削する第2の掘削ビット222に施工抵抗を負担させ、その分だけ施工抵抗が軽減される第1の掘削ビット221の摩耗を抑制することができる。上述のように、第2の掘削ビット222の突出高さH2を第1の掘削ビット221の突出高さH1よりも高くことによっても、第1の掘削ビット221の摩耗は抑制される。従って、本実施形態では、より効果的に第1の掘削ビット221の摩耗を抑制し、地盤強度が高い層で掘削を進めても掘削ビット22による管内土の閉塞の抑制または促進の機能を維持することができる。
With the above configuration, the construction resistance is borne by the second excavation bit 222 that excavates the relatively expanded area, and the wear of the first excavation bit 221 whose construction resistance is reduced by that amount is suppressed. be able to. As described above, the wear of the first excavation bit 221 is also suppressed by making the protrusion height H 2 of the second excavation bit 222 higher than the protrusion height H 1 of the first excavation bit 221. Therefore, in the present embodiment, the wear of the first excavation bit 221 is suppressed more effectively, and the function of suppressing or promoting the blockage of the in-pipe soil by the excavation bit 22 is maintained even if the excavation is advanced in the layer having high ground strength. can do.
なお、上記の第1の実施形態で図4および図5を参照して説明したような変形例は、本実施形態にも適用可能である。具体的には、図7に示す例のように、掘削ビット221A,222Aの少なくともいずれかの先端面221E,222Eに鋼管本体11の径方向の内側から外側に向かって突出高さが高くなる傾斜が形成されてもよい。また、図8に示す例のように、掘削ビット221,222Bの少なくともいずれかが、鋼管本体11の径方向の内側から外側に向かって厚くなるテーパー断面で形成されてもよい。
Note that the modified examples as described with reference to FIGS. 4 and 5 in the first embodiment described above can also be applied to the present embodiment. Specifically, as shown in the example shown in FIG. 7, an inclination in which the protruding height of the steel pipe body 11 increases from the inside to the outside in the radial direction on at least one of the tip surfaces 221E and 222E of the excavation bits 221A and 222A. May be formed. Further, as in the example shown in FIG. 8, at least one of the excavation bits 221 and 222B may be formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body 11.
(第3の実施形態)
図9は、本発明の第3の実施形態に係る鋼管杭を側方および先端側から見た図である。図6に示されるように、鋼管杭30は、鋼管本体11と、鋼管本体11の端面11Eに取り付けられる掘削ビット32とを含む。掘削ビット32は、第1の掘削ビット321および第2の掘削ビット322を含む。第1の実施形態と同様に、第1の掘削ビット321は鋼管本体11の端面11Eから高さH1だけ突出し、第2の掘削ビット322は鋼管本体11の端面11Eから高さH2だけ突出し、高さH2は高さH1よりも高い(H1<H2)。さらに、本実施形態において、第1の掘削ビット321の取り付け方向に沿った長さはL1であり、第2の掘削ビット322の取り付け方向に沿った長さはL2であり、長さL2は長さL1よりも長い(L1<L2)。一方、本実施形態において、第1の掘削ビット321および第2の掘削ビット322は、鋼管本体11の周方向接線に対して同じ取り付け角度θ(0<θ<90°)で取り付けられている。第1の掘削ビット321および第2の掘削ビット322の取り付け方向は、鋼管本体11の周方向接線、すなわち管厚中心線LC11の接線LT11に対して取り付け角度θだけ傾いた方向である。 (Third Embodiment)
FIG. 9 is a view of the steel pipe pile according to the third embodiment of the present invention as viewed from the side and the tip side. As shown in FIG. 6, thesteel pipe pile 30 includes a steel pipe main body 11 and a drilling bit 32 attached to an end surface 11E of the steel pipe main body 11. The excavation bit 32 includes a first excavation bit 321 and a second excavation bit 322. Like the first embodiment, by a height H 1 protrudes from the end surface 11E of the first drill bit 321 steel body 11, second drill bit 322 by a height H 2 protrudes from the end surface 11E of the steel pipe body 11 , Height H 2 is higher than height H 1 (H 1 <H 2 ). Further, in the present embodiment, the length along the attachment direction of the first excavation bit 321 is L1, the length along the attachment direction of the second excavation bit 322 is L2, and the length L2 is the length. Is longer than L1 (L1 <L2). On the other hand, in the present embodiment, the first excavation bit 321 and the second excavation bit 322 are attached at the same attachment angle θ (0 <θ <90 °) with respect to the circumferential tangent of the steel pipe main body 11. Mounting direction of the first drilling bit 321 and the second drill bit 322, the circumferential tangent of the steel pipe body 11, that is, a direction inclined by fitting angle θ to a tangent L T11 of pipe thickness center line L C11.
図9は、本発明の第3の実施形態に係る鋼管杭を側方および先端側から見た図である。図6に示されるように、鋼管杭30は、鋼管本体11と、鋼管本体11の端面11Eに取り付けられる掘削ビット32とを含む。掘削ビット32は、第1の掘削ビット321および第2の掘削ビット322を含む。第1の実施形態と同様に、第1の掘削ビット321は鋼管本体11の端面11Eから高さH1だけ突出し、第2の掘削ビット322は鋼管本体11の端面11Eから高さH2だけ突出し、高さH2は高さH1よりも高い(H1<H2)。さらに、本実施形態において、第1の掘削ビット321の取り付け方向に沿った長さはL1であり、第2の掘削ビット322の取り付け方向に沿った長さはL2であり、長さL2は長さL1よりも長い(L1<L2)。一方、本実施形態において、第1の掘削ビット321および第2の掘削ビット322は、鋼管本体11の周方向接線に対して同じ取り付け角度θ(0<θ<90°)で取り付けられている。第1の掘削ビット321および第2の掘削ビット322の取り付け方向は、鋼管本体11の周方向接線、すなわち管厚中心線LC11の接線LT11に対して取り付け角度θだけ傾いた方向である。 (Third Embodiment)
FIG. 9 is a view of the steel pipe pile according to the third embodiment of the present invention as viewed from the side and the tip side. As shown in FIG. 6, the
上記のように掘削ビット32が取り付け角度θを有することによって、本実施形態でも第1の実施形態と同様に、鋼管杭30を図9に示す反時計回り(CCW)および時計回り(CW)のそれぞれに回転させながら掘削するときに、管内土の閉塞を抑制または促進する効果が得られる。
Since the excavation bit 32 has the mounting angle θ as described above, the steel pipe pile 30 is rotated counterclockwise (CCW) and clockwise (CW) shown in FIG. 9 in the present embodiment as in the first embodiment. When excavating while rotating each of them, the effect of suppressing or promoting the blockage of the soil inside the pipe can be obtained.
加えて、本実施形態では、第2の掘削ビット322の取り付け方向に沿った長さL2が第1の掘削ビット321の取り付け方向に沿った長さL1よりも長い。これによって、第1の掘削ビット321および第2の掘削ビット322の取り付け角度θが同じであっても、例えば鋼管本体11の径方向外側について、第1の掘削ビット321が管厚中心線LC11から鋼管本体11の径方向に突出する距離D1よりも、第2の掘削ビット322が管厚中心線LC11から鋼管本体11の径方向に突出する距離D2の方が長くなる。これによって、鋼管本体11の外側で、第1の掘削ビット321の掘削可能領域R1よりも第2の掘削ビット322の掘削可能領域R2が拡張される。例えば、鋼管本体11の外側について、図6に示すように掘削可能領域R1の半径をr1、掘削可能領域R2の半径をr2とした場合、r2/r1=1.2程度になるように長さL1,L2を設定してもよい。
In addition, in the present embodiment, the length L2 along the attachment direction of the second excavation bit 322 is longer than the length L1 along the attachment direction of the first excavation bit 321. Thus, even the mounting angle θ of the first drill bit 321 and the second drill bit 322 is the same, for example, the radially outer steel body 11, a first drill bit 321 is the pipe thickness center line L C11 than the distance D1 which projects in the radial direction of the steel pipe body 11 from Trip distance D2 where the second drill bit 322 protrudes from the wall thickness center line L C11 in the radial direction of the steel pipe body 11 becomes longer. As a result, on the outside of the steel pipe main body 11, the excavable region R2 of the second excavation bit 322 is expanded more than the excavable region R1 of the first excavation bit 321. For example, regarding the outside of the steel pipe main body 11, when the radius of the excavable region R1 is r1 and the radius of the excavable region R2 is r2 as shown in FIG. 6, the length is about r2 / r1 = 1.2. L1 and L2 may be set.
なお、本実施形態では、第1の掘削ビット321および第2の掘削ビット322がいずれも鋼管本体11の径方向の外側および内側の両方に突出し、かつ取り付け方向の中心で鋼管本体11の管厚中心線LC11に交差するため、鋼管本体11の内側でも同様に、第1の掘削ビット321が突出する距離よりも第2の掘削ビット322が突出する距離の方が長く、掘削可能領域R1よりも掘削可能領域R2が拡張される。他の例では、鋼管本体11の径方向の外側または内側のいずれか一方だけで掘削可能領域が拡張されてもよい。
In the present embodiment, both the first excavation bit 321 and the second excavation bit 322 project to both the outside and the inside of the steel pipe body 11 in the radial direction, and the pipe thickness of the steel pipe body 11 is at the center of the mounting direction. Since it intersects the center line LC11 , the distance that the second excavation bit 322 protrudes is longer than the distance that the first excavation bit 321 protrudes inside the steel pipe main body 11, and the distance that the second excavation bit 322 protrudes is longer than the excavable area R1. The excavable area R2 is also expanded. In another example, the excavable area may be extended only on either the outside or the inside of the steel pipe body 11 in the radial direction.
上記のような構成によって、相対的に拡張された領域を掘削する第2の掘削ビット322に施工抵抗を負担させ、その分だけ施工抵抗が軽減される第1の掘削ビット321の摩耗を抑制することができる。上述のように、第2の掘削ビット322の突出高さH2を第1の掘削ビット321の突出高さH1よりも高くことによっても、第1の掘削ビット321の摩耗は抑制される。従って、本実施形態では、より効果的に第1の掘削ビット321の摩耗を抑制し、地盤強度が高い層で掘削を進めても掘削ビット32による管内土の閉塞の抑制または促進の機能を維持することができる。
With the above configuration, the construction resistance is borne by the second excavation bit 322 that excavates the relatively expanded area, and the wear of the first excavation bit 321 whose construction resistance is reduced by that amount is suppressed. be able to. As described above, the wear of the first excavation bit 321 is also suppressed by making the protrusion height H 2 of the second excavation bit 322 higher than the protrusion height H 1 of the first excavation bit 321. Therefore, in the present embodiment, the wear of the first excavation bit 321 is more effectively suppressed, and the function of suppressing or promoting the blockage of the in-pipe soil by the excavation bit 32 is maintained even when excavation is carried out in a layer having high ground strength. can do.
なお、以上で説明した本発明の第2および第3の実施形態は、互いに組み合わせることが可能である。つまり、本発明の実施形態では、第2の掘削ビット322の突出高さH2を第1の掘削ビット321の突出高さH1よりも高くするのに加えて、一部の掘削ビットの取り付け角度θまたは取り付け方向に沿った長さLのいずれかを他の掘削ビットよりも大きくすることによって掘削可能領域を拡張してもよいし、取り付け角度θおよび長さLの両方を他の掘削ビットよりも大きくすることによって掘削可能領域を拡張してもよい。
The second and third embodiments of the present invention described above can be combined with each other. That is, in the embodiment of the present invention, in addition to making the protrusion height H 2 of the second excavation bit 322 higher than the protrusion height H 1 of the first excavation bit 321, the attachment of some excavation bits. The excavable area may be extended by making either the angle θ or the length L along the mounting direction larger than the other drilling bits, or both the mounting angle θ and the length L may be the other drilling bits. The excavable area may be expanded by making it larger than.
また、上記の第1の実施形態で図4および図5を参照して説明したような変形例は、本実施形態にも適用可能である。具体的には、少なくともいずれかの掘削ビットの先端面に鋼管本体の径方向の内側から外側に向かって突出高さが高くなる傾斜が形成されてもよいし、少なくともいずれかの掘削ビットが鋼管本体の径方向の内側から外側に向かって厚くなるテーパー断面で形成されてもよい。
Further, the modified example as described with reference to FIGS. 4 and 5 in the first embodiment described above is also applicable to the present embodiment. Specifically, the tip surface of at least one of the excavation bits may be inclined so that the protruding height increases from the inside to the outside in the radial direction of the steel pipe body, or at least one of the excavation bits is a steel pipe. It may be formed with a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the main body.
(変形例)
図10から図14は、上記で説明した第1から第3の実施形態の変形例を示す図である。以下で説明する変形例は、第1の実施形態から第3の実施形態のそれぞれに、また、第2の実施形態と第3の実施形態とを組み合わせた実施形態に適用可能である。各図に示された鋼管杭40において、掘削ビット42は、第1の掘削ビット421および第2の掘削ビット422を含む。第1の掘削ビット421と第2の掘削ビット422との間では、上記で説明した第1から第3の実施形態と同様に突出高さ、取り付け角度θまたは長さLが異なっているが、図10から図14の各図において、このような第1の掘削ビットと第2の掘削ビットとの形状の違いは必ずしも図示されていない。また、各図に示された例ではそれぞれの掘削ビットが鋼管本体11の径方向の外側および内側の両方に突出し、かつ取り付け方向の中心で鋼管本体11の管厚中心線に交差するが、鋼管本体11の径方向の外側または内側のいずれか一方だけに掘削ビットが突出していてもよい点は、上記の各実施形態と同様である。 (Modification)
10 to 14 are views showing modified examples of the first to third embodiments described above. The modifications described below are applicable to each of the first to third embodiments, and to the embodiment in which the second embodiment and the third embodiment are combined. In thesteel pipe pile 40 shown in each figure, the excavation bit 42 includes a first excavation bit 421 and a second excavation bit 422. The protrusion height, the mounting angle θ, or the length L are different between the first excavation bit 421 and the second excavation bit 422 as in the first to third embodiments described above. In each of the drawings of FIGS. 10 to 14, such a difference in shape between the first excavation bit and the second excavation bit is not necessarily shown. Further, in the example shown in each figure, each drilling bit protrudes both outward and inside in the radial direction of the steel pipe body 11 and intersects the pipe thickness center line of the steel pipe body 11 at the center in the mounting direction. Similar to each of the above-described embodiments, the excavation bit may protrude only on either the outer side or the inner side in the radial direction of the main body 11.
図10から図14は、上記で説明した第1から第3の実施形態の変形例を示す図である。以下で説明する変形例は、第1の実施形態から第3の実施形態のそれぞれに、また、第2の実施形態と第3の実施形態とを組み合わせた実施形態に適用可能である。各図に示された鋼管杭40において、掘削ビット42は、第1の掘削ビット421および第2の掘削ビット422を含む。第1の掘削ビット421と第2の掘削ビット422との間では、上記で説明した第1から第3の実施形態と同様に突出高さ、取り付け角度θまたは長さLが異なっているが、図10から図14の各図において、このような第1の掘削ビットと第2の掘削ビットとの形状の違いは必ずしも図示されていない。また、各図に示された例ではそれぞれの掘削ビットが鋼管本体11の径方向の外側および内側の両方に突出し、かつ取り付け方向の中心で鋼管本体11の管厚中心線に交差するが、鋼管本体11の径方向の外側または内側のいずれか一方だけに掘削ビットが突出していてもよい点は、上記の各実施形態と同様である。 (Modification)
10 to 14 are views showing modified examples of the first to third embodiments described above. The modifications described below are applicable to each of the first to third embodiments, and to the embodiment in which the second embodiment and the third embodiment are combined. In the
図10および図11に示された例では、鋼管本体11の周方向における第1の掘削ビット421および第2の掘削ビット422の配置パターンが上記の各実施形態とは異なる。より具体的には、上記の各実施形態では第1の掘削ビットと第2の掘削ビットとが1つおきに交互に配置されていたのに対し、図10に示される鋼管杭40では、第1の掘削ビット421と第2の掘削ビット422とが2つおきに交互に配置される。また、上記の各実施形態では第1の掘削ビットと第2の掘削ビットとが同じ数だけ配置されていたのに対し、図11に示される鋼管杭40では、第1の掘削ビット421を1つ配置するごとに第2の掘削ビット422が2つ配置され、従って第1の掘削ビット421の数よりも第2の掘削ビット422の数の方が多い。
In the examples shown in FIGS. 10 and 11, the arrangement pattern of the first excavation bit 421 and the second excavation bit 422 in the circumferential direction of the steel pipe main body 11 is different from each of the above embodiments. More specifically, in each of the above embodiments, the first excavation bit and the second excavation bit are alternately arranged alternately, whereas in the steel pipe pile 40 shown in FIG. 10, the first excavation bit and the second excavation bit are arranged alternately. The first excavation bit 421 and the second excavation bit 422 are alternately arranged every two. Further, in each of the above embodiments, the same number of the first excavation bit and the second excavation bit are arranged, whereas in the steel pipe pile 40 shown in FIG. 11, the first excavation bit 421 is set to 1. Two second excavation bits 422 are arranged for each arrangement, and therefore the number of second excavation bits 422 is greater than the number of first excavation bits 421.
図12に示された例では、掘削ビット42が、第1の掘削ビット421および第2の掘削ビット422に加えて第3の掘削ビット423および第4の掘削ビット424を含む。第3の掘削ビット423は、第2の掘削ビット422よりもさらに突出高さが高い(つまり、鋼管本体11の端面11Eから高さH2よりも高い第3の高さだけ突出する)。さらに、第3の掘削ビット423は、第2の掘削ビット422よりもさらに突出する距離が長い(つまり、鋼管本体11の管厚中心線LC11から鋼管本体11の径方向に距離D2(図6または図9などを参照)よりも長い第3の距離だけ突出する)ことによって、第2の掘削ビット422の掘削可能領域R2よりも拡張された掘削可能領域を有してもよい。第3の掘削ビット423と第4の掘削ビット424との関係についても第2の掘削ビット422と第3の掘削ビット423との関係と同様であり、第4の掘削ビット424は、例えば、第3の掘削ビット423よりもさらに突出高さが高く、第3の掘削ビット423よりもさらに拡張された掘削可能領域を有してもよい。このように、本発明の実施形態において、掘削ビットは、2種類の掘削ビットに限らず、3種類、または4種類以上の掘削ビットを含んでもよい。この場合、3種類以上の掘削ビットは、例えば図12に示された例における第2の掘削ビット422および第3の掘削ビット423のように、先行して施工抵抗を負担する掘削ビットが存在するために最初は摩耗が抑制され、先行する掘削ビットが摩耗した後は後に位置する別の掘削ビットの摩耗を抑制するために施工抵抗を負担する中間的な掘削ビットを含む。
In the example shown in FIG. 12, the drilling bit 42 includes a third drilling bit 423 and a fourth drilling bit 424 in addition to the first drilling bit 421 and the second drilling bit 422. The third drill bit 423 (only protrudes higher third height than the height H 2 from the other words, the end surface 11E of the steel pipe main body 11) further protruding height greater than the second drill bit 422. Further, a third drill bit 423, the distance to further protrude from the second drill bit 422 is long (i.e., the distance from the wall thickness center line L C11 in the radial direction of the steel pipe body 11 of the steel pipe body 11 D2 (FIG. 6 Alternatively, it may have an excavable area extended beyond the excavable area R2 of the second excavation bit 422) by projecting by a third distance longer than (see FIG. 9 and the like). The relationship between the third excavation bit 423 and the fourth excavation bit 424 is the same as the relationship between the second excavation bit 422 and the third excavation bit 423, and the fourth excavation bit 424 is, for example, the first. It may have an excavable area that is even higher than the excavation bit 423 of 3 and further expanded than the excavation bit 423 of the third excavation bit 423. As described above, in the embodiment of the present invention, the excavation bit is not limited to the two types of excavation bits, and may include three types or four or more types of excavation bits. In this case, as for the three or more types of excavation bits, there are excavation bits that bear the construction resistance in advance, such as the second excavation bit 422 and the third excavation bit 423 in the example shown in FIG. This includes an intermediate excavation bit that initially suppresses wear and then bears construction resistance to suppress wear of another excavation bit located later after the preceding excavation bit wears.
図13および図14に示された例では、第1の掘削ビット421および第2の掘削ビット422を含む掘削ビット42が、湾曲した板状の掘削ビットである。図13の例では、掘削ビット42が、鋼管杭40を先端側から見たときにC字状になるように湾曲している。この場合、掘削ビット42の取り付け角度θは、掘削ビット42の湾曲した板厚中心線LC42が鋼管本体11の管厚中心線LC11に交わる位置において、板厚中心線LC42の接線LT42と管厚中心線LC11の接線LT11とがなす角度である。また、掘削ビット42の取り付け方向に沿った長さLは、接線LT42に沿った方向の長さである。図13の例では、例えば上記の各実施形態と同様の効果が得られるのに加えて、掘削ビット42が湾曲していることによって、鋼管杭40が反時計回り(CCW)で回転するときには鋼管本体11および掘削ビット42から離れる向きの土砂の流れF1を生み出しやすく、また鋼管杭40が時計回り(CW)で回転するときには鋼管本体11の内側に向かう土砂の流れF2を生み出しやすくなる。土砂の流れがスムーズになることによって、鋼管杭40を用いた掘削がより円滑になる。
In the example shown in FIGS. 13 and 14, the excavation bit 42 including the first excavation bit 421 and the second excavation bit 422 is a curved plate-shaped excavation bit. In the example of FIG. 13, the excavation bit 42 is curved so as to have a C shape when the steel pipe pile 40 is viewed from the tip side. In this case, the mounting angle θ of the drill bit 42, at a position intersecting the wall thickness center line L C11 curved thickness center line L C42 steel pipe body 11 of the drill bit 42, the tangent of the thickness center line L C42 L T42 that the angle between the tangential line L T11 of pipe thickness center line L C11. Further, the length L along the attachment direction of the excavation bit 42 is the length in the direction along the tangent line LT42 . In the example of FIG. 13, for example, in addition to obtaining the same effect as in each of the above embodiments, the curved excavation bit 42 causes the steel pipe when the steel pipe pile 40 rotates counterclockwise (CCW). easily create flow F 1 of the sediment away from the main body 11 and the drill bit 42, also steel pipe pile 40 tends produces a flow F 2 of sediment towards the inside of the steel pipe body 11 when rotating clockwise (CW). By smoothing the flow of earth and sand, excavation using the steel pipe pile 40 becomes smoother.
一方、図14の例では、掘削ビット42が、鋼管杭40を先端側から見たときにS字状になるように湾曲している。この場合、掘削ビット42の取り付け角度θは、掘削ビット42の湾曲した板厚中心線LC42が鋼管本体11の管厚中心線LC11に交わる位置において、掘削ビット42の両端の板厚中心を結ぶ直線LE42と管厚中心線LC11の接線LT11とがなす角度である。また、掘削ビット42の取り付け方向に沿った長さLは、直線LE42に沿った方向の長さである。図14の例では、図13の例と同様の土砂の流れF1,F2が生み出しやすくなるのに加えて、鋼管杭40が時計回り(CW)に回転するときに鋼管本体11の内側に取り込まれた土砂が掘削ビット42から離れる向きの土砂の流れF3を生み出しやすくなる。図13の例と同様に、土砂の流れがスムーズになることによって、鋼管杭40を用いた掘削がより円滑になる。
On the other hand, in the example of FIG. 14, the excavation bit 42 is curved so as to have an S shape when the steel pipe pile 40 is viewed from the tip side. In this case, the mounting angle θ of the drill bit 42, at a position where the curved thickness center line L C42 of the drill bit 42 intersects the wall thickness center line L C11 steel pipe body 11, the thickness center of the opposite ends of the drill bit 42 it is an angle formed by the tangent line L T11 linear L E42 and pipe thickness center line L C11 connecting the. Further, the length L along the attachment direction of the excavation bit 42 is the length in the direction along the straight line LE 42 . In the example of FIG. 14, in addition to becoming tends produced examples and similar of sediment flow F 1, F 2 in FIG. 13, the inside of the steel pipe body 11 when the steel pipe pile 40 is rotated clockwise (CW) captured sediment is likely produced the sediment flow F 3 direction away from the drill bit 42. Similar to the example of FIG. 13, the smooth flow of earth and sand makes excavation using the steel pipe pile 40 smoother.
なお、上述した第1から第3の実施形態、およびそれらの変形例において、掘削ビットが鋼管本体11の内側および外側の両方に突出するか、または掘削ビットが鋼管本体11の内側にのみ突出する構成が可能である。第1の掘削ビットと第2の掘削ビット(および第3の掘削ビットならびに第4の掘削ビット)との間で、掘削ビットが鋼管本体11から突出する方向が異なっていてもよい。
In the first to third embodiments described above and their modifications, the excavation bit protrudes both inside and outside the steel pipe body 11, or the excavation bit projects only inside the steel pipe body 11. It can be configured. The direction in which the excavation bit protrudes from the steel pipe body 11 may be different between the first excavation bit and the second excavation bit (and the third excavation bit and the fourth excavation bit).
(鋼管杭の施工方法)
上記で説明したような本発明の実施形態および変形例に係る鋼管杭を用いて、例えば以下のような施工方法が実施可能である。なお、以下ではで図1を参照して説明した鋼管杭10を例として説明するが、第2および第3の実施形態や各変形例に係る鋼管杭20,30,40でも同様の施工方法が実施可能である。 (Construction method of steel pipe pile)
Using the steel pipe piles according to the embodiments and modifications of the present invention as described above, for example, the following construction methods can be implemented. In the following, thesteel pipe pile 10 described with reference to FIG. 1 will be described as an example, but the same construction method can be applied to the steel pipe piles 20, 30, and 40 according to the second and third embodiments and the modified examples. It is feasible.
上記で説明したような本発明の実施形態および変形例に係る鋼管杭を用いて、例えば以下のような施工方法が実施可能である。なお、以下ではで図1を参照して説明した鋼管杭10を例として説明するが、第2および第3の実施形態や各変形例に係る鋼管杭20,30,40でも同様の施工方法が実施可能である。 (Construction method of steel pipe pile)
Using the steel pipe piles according to the embodiments and modifications of the present invention as described above, for example, the following construction methods can be implemented. In the following, the
まず、鋼管杭10の先端(掘削ビット12の先端、または鋼管本体11の端面11E)が所定の深度に到達するまで、掘削ビット12が土砂を鋼管本体11の外側に押し出す第1の回転方向(図1に示す反時計回り(CCW))に鋼管杭10を回転させながら掘削する工程が実施される。その後、鋼管杭10の先端が打ち止め深さに到達するまで、掘削ビット12が土砂を鋼管本体11の内側に取り込む第2の回転方向(図1に示す時計回り(CW))に鋼管杭10を回転させながら掘削する工程が実施される。ここで、所定の深度は、例えば打ち止め深さに対して鋼管本体11の直径の1倍~5倍程度の距離だけ上方である。これによって、鋼管杭10の打ち止め時においては、鋼管杭10の下端部を取り込んだ土砂で閉塞させて、高い支持力を得ることができる。
First, until the tip of the steel pipe pile 10 (the tip of the drilling bit 12 or the end face 11E of the steel pipe body 11) reaches a predetermined depth, the drilling bit 12 pushes the earth and sand to the outside of the steel pipe body 11 in the first rotation direction ( The step of excavating while rotating the steel pipe pile 10 in the counterclockwise direction (CCW) shown in FIG. 1 is carried out. After that, the steel pipe pile 10 is placed in the second rotation direction (clockwise (CW) shown in FIG. 1) in which the excavation bit 12 takes in the earth and sand inside the steel pipe main body 11 until the tip of the steel pipe pile 10 reaches the stopping depth. The process of excavating while rotating is carried out. Here, the predetermined depth is, for example, upward by a distance of about 1 to 5 times the diameter of the steel pipe main body 11 with respect to the stopping depth. As a result, when the steel pipe pile 10 is stopped, the lower end of the steel pipe pile 10 can be closed with the captured earth and sand to obtain a high bearing capacity.
なお、上記の所定の深度と、地盤中の支持層の深さとの関係は任意である。つまり、所定の深度は、支持層の深さよりも深くてもよい。この場合、施工方法では、打ち止めの際に、鋼管杭10の先端を支持層に到達させてから、鋼管杭10を第2の回転方向に回転させることになる。あるいは、所定の深度は、支持層の深さよりも浅くてもよい。この場合、施工方法では、打ち止めの際に、鋼管杭10の先端が支持層に到達する直前から、鋼管杭10を第2の回転方向に回転させながら掘削し、鋼管杭10の先端が支持層に到達してから打ち止めることになる。
The relationship between the above-mentioned predetermined depth and the depth of the support layer in the ground is arbitrary. That is, the predetermined depth may be deeper than the depth of the support layer. In this case, in the construction method, the tip of the steel pipe pile 10 reaches the support layer at the time of stopping, and then the steel pipe pile 10 is rotated in the second rotation direction. Alternatively, the predetermined depth may be shallower than the depth of the support layer. In this case, in the construction method, at the time of stopping, the steel pipe pile 10 is excavated while rotating in the second rotation direction immediately before the tip of the steel pipe pile 10 reaches the support layer, and the tip of the steel pipe pile 10 is the support layer. Will be stopped after reaching.
また、施工方法において、鋼管杭10を第1の回転方向に回転させながら掘削する工程と、鋼管杭10を第2の回転方向に回転させながら掘削する工程とは、交互に実施されてもよい。つまり、鋼管杭10の先端が所定の深度に到達する前であっても、鋼管杭10を第2の回転方向に回転させながら掘削することは可能である。具体的には、例えば鋼管杭10の根入れが順調ではないような場合に、鋼管杭10の回転方向を交互に切り替えながら根入れし、最終的には鋼管杭10を第2の回転方向に回転させて打ち止めることが考えられる。この場合、所定の深度は、鋼管杭10が最後に第1の回転方向に回転させられた深度であり、例えば打ち止め深さと同程度の深さでありうる。例えば上記のような場合において、鋼管杭10の回転方向だけではなく、鋼管杭10の掘削(先端の下降)および後退(先端の上昇)を交互に実施してもよい。
Further, in the construction method, the step of excavating while rotating the steel pipe pile 10 in the first rotation direction and the step of excavating while rotating the steel pipe pile 10 in the second rotation direction may be alternately performed. .. That is, even before the tip of the steel pipe pile 10 reaches a predetermined depth, it is possible to excavate the steel pipe pile 10 while rotating it in the second rotation direction. Specifically, for example, when the rooting of the steel pipe pile 10 is not smooth, the steel pipe pile 10 is rooted while alternately switching the rotation direction, and finally the steel pipe pile 10 is set to the second rotation direction. It is conceivable to rotate and stop. In this case, the predetermined depth is the depth at which the steel pipe pile 10 is finally rotated in the first rotation direction, and may be, for example, a depth similar to the stopping depth. For example, in the above case, excavation (lowering of the tip) and retreat (rising of the tip) of the steel pipe pile 10 may be alternately performed as well as the rotation direction of the steel pipe pile 10.
図15は、掘削ビットの取り付け角度に関する実験結果を示すグラフである。実験では、断面直径101.6mm、管厚5.7mmの鋼管本体に、厚さ6mm、取り付け方向に沿った長さ30mm、鋼管本体の端面からの突出高さ12mmの掘削ビットを等間隔で4つ取り付け、掘削ビットの取り付け角度を0°(取り付け角度なし)、5°、15°、20°および30°の5通りにした場合について、飯豊珪砂7号を用いた模擬地盤に同じ深度まで打設した鋼管杭の支持力を比較した。なお、この実験では、「道路橋示方書・同解説(IV 下部構造編)」に準拠し、杭頭(鋼管頭部)の沈下量が杭径(断面直径)の10%のときの荷重(極限支持力)を支持力としている。また、支持力は取り付け角度がない場合を1とした場合の増加比率で表現されている。図15のグラフに示されるように、取り付け角度がある(0°よりも大きい)場合は、取り付け角度がない場合に比べて支持力が向上する。特に、取り付け角度が5°から15°の範囲で、より顕著な支持力の向上がみられた(0°の場合の約1.25倍以上)。この結果から、例えば、上述した各実施形態において、掘削ビットの取り付け角度θ,θ1,θ2を5°以上15°以下(5°≦θ,θ1,θ2≦15°)の範囲に設定してもよい。なお、上記の範囲外の場合でも支持力は向上するため、取り付け角度θ,θ1,θ2の値は上記の範囲には限定されない。
FIG. 15 is a graph showing the experimental results regarding the mounting angle of the excavation bit. In the experiment, excavation bits having a thickness of 6 mm, a length of 30 mm along the mounting direction, and a protrusion height of 12 mm from the end face of the steel pipe body were placed at equal intervals on a steel pipe body having a cross-sectional diameter of 101.6 mm and a pipe thickness of 5.7 mm. When the mounting angle of the excavation bit is 0 ° (no mounting angle), 5 °, 15 °, 20 ° and 30 °, hit the simulated ground using Iitoyo silica sand No. 7 to the same depth. The bearing capacity of the installed steel pipe piles was compared. In this experiment, the load when the amount of sinking of the pile head (steel pipe head) is 10% of the pile diameter (cross-sectional diameter) is based on the "Road Bridge Specification / Explanation (IV Substructure)". (Ultimate bearing capacity) is the bearing capacity. Further, the bearing capacity is expressed by an increase rate when 1 is set when there is no mounting angle. As shown in the graph of FIG. 15, when there is a mounting angle (greater than 0 °), the bearing capacity is improved as compared with the case where there is no mounting angle. In particular, when the mounting angle was in the range of 5 ° to 15 °, a more remarkable improvement in bearing capacity was observed (about 1.25 times or more in the case of 0 °). From this result, for example, in each of the above-described embodiments, even if the mounting angles θ, θ1, θ2 of the excavation bit are set in the range of 5 ° or more and 15 ° or less (5 ° ≦ θ, θ1, θ2 ≦ 15 °). Good. Since the bearing capacity is improved even outside the above range, the values of the mounting angles θ, θ1 and θ2 are not limited to the above range.
図16は、掘削ビットの摩耗抑制効果について検証する実験について説明するための図である。図示されているように、実験では、断面直径101.6mm、管厚5.7mmの鋼管本体11に、厚さ3.2mm、取り付け方向に沿った長さ30mmの掘削ビット121,122を等間隔で4つ取り付けた。実施例1では、このうち2つの掘削ビット121については、鋼管本体の端面からの突出高さを10mmとし、残りの2つの掘削ビット122については突出高さを14mmとし、掘削ビット121と掘削ビット122とを鋼管本体11の周方向について交互に配置した。掘削ビットの取り付け角度はいずれも10°である。実施例2では、実施例1の突出高さの差に加えて、掘削ビット121について取り付け角度を10°とし、掘削ビット122については取り付け角度を15°とした。掘削ビット121,122は、いずれも鋼管本体11の外側および内側の両方に突出し、かつ取り付け方向の中心で鋼管本体11の管厚中心線に交差する。なお、図16は、この実施例2の条件を示している。比較例では、同様に4つの掘削ビットを取り付けたが、すべての掘削ビットで突出高さを12mm、取り付け角度を10°とした。
FIG. 16 is a diagram for explaining an experiment for verifying the wear suppressing effect of the excavation bit. As shown in the experiment, in the experiment, excavation bits 121 and 122 having a thickness of 3.2 mm and a length of 30 mm along the mounting direction were equally spaced on a steel pipe body 11 having a cross-sectional diameter of 101.6 mm and a pipe thickness of 5.7 mm. I installed four. In the first embodiment, two of the excavation bits 121 have a protrusion height of 10 mm from the end face of the steel pipe body, and the remaining two excavation bits 122 have a protrusion height of 14 mm, and the excavation bit 121 and the excavation bit 122 and 122 were alternately arranged in the circumferential direction of the steel pipe main body 11. The mounting angle of the excavation bit is 10 °. In the second embodiment, in addition to the difference in the protrusion height of the first embodiment, the mounting angle of the excavation bit 121 is set to 10 °, and the mounting angle of the excavation bit 122 is set to 15 °. The excavation bits 121 and 122 both project to both the outside and the inside of the steel pipe body 11 and intersect the pipe thickness center line of the steel pipe body 11 at the center in the mounting direction. Note that FIG. 16 shows the conditions of the second embodiment. In the comparative example, four excavation bits were similarly attached, but the protrusion height was 12 mm and the attachment angle was 10 ° for all the excavation bits.
図17は、図16に示した実験の結果を示すグラフである。図16を参照して説明したような実施例1、実施例2および比較例に係る鋼管杭で、モルタル状の模型地盤を施工深度500mm分掘削した。その結果、グラフに示されるように、取り付け角度および掘削可能領域がすべての掘削ビットで同じである比較例における各ビットの体積残存率を1とした場合に、突出高さの異なる2組の掘削ビットを配置した実施例1では、突出高さが低い掘削ビット121の体積残存率が比較例の4.85倍であった。ここで、体積残存率は、施工前の掘削ビットの体積に対して、施工後に残存した掘削ビットの体積の割合である。さらに、2組の掘削ビットの突出高さに加えて掘削可能領域も異なる実施例2では、突出高さが低く掘削可能領域が小さい掘削ビット121の体積残存率が比較例の5.23倍であった。この結果は、複数の掘削ビットの間で突出高さを異ならせることによって掘削時の摩耗に対抗して掘削ビットの機能を維持できること、また、突出高さに加えて掘削可能領域の大きさを異ならせることによって効果が向上することを示している。
FIG. 17 is a graph showing the results of the experiment shown in FIG. A mortar-shaped model ground was excavated at a construction depth of 500 mm with the steel pipe piles according to Examples 1, 2 and Comparative Examples as described with reference to FIG. As a result, as shown in the graph, when the volume residual ratio of each bit in the comparative example in which the mounting angle and the excavable area are the same for all the excavation bits is 1, two sets of excavations having different protrusion heights are excavated. In Example 1 in which the bits were arranged, the volume residual ratio of the excavation bit 121 having a low protrusion height was 4.85 times that of the comparative example. Here, the volume residual ratio is the ratio of the volume of the excavation bit remaining after the construction to the volume of the excavation bit before the construction. Further, in Example 2 in which the excavable area is different in addition to the protruding heights of the two sets of excavating bits, the volume residual ratio of the excavating bits 121 having a low protruding height and a small excavable area is 5.23 times that of the comparative example. there were. The result is that the function of the excavation bit can be maintained against wear during excavation by making the projecting height different among multiple excavation bits, and the size of the excavable area in addition to the projecting height. It is shown that the effect is improved by making them different.
以上、添付図面を参照しながら本発明の好適な実施形態について詳細に説明したが、本発明はかかる例に限定されない。本発明の属する技術の分野における通常の知識を有する者であれば、請求の範囲に記載された技術的思想の範囲内において、各種の変形例または修正例に想到し得ることは明らかであり、これらについても、当然に本発明の技術的範囲に属するものと了解される。
Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. It is naturally understood that these also belong to the technical scope of the present invention.
10,20,30,40…鋼管杭、11…鋼管本体、11E…端面、12,22,32,42…掘削ビット、121,121A,221,221A,321,421…第1の掘削ビット、121E,221E…先端面、122,122A,122B,222,222A,222B,322,422…第2の掘削ビット、122E,222E…先端面、423…第3の掘削ビット、424…第4の掘削ビット。
10, 20, 30, 40 ... Steel pipe pile, 11 ... Steel pipe body, 11E ... End face, 12, 22, 32, 42 ... Excavation bit, 121, 121A, 221,221A, 321, 421 ... First excavation bit, 121E , 221E ... Tip surface, 122, 122A, 122B, 222, 222A, 222B, 322, 422 ... Second drilling bit, 122E, 222E ... Tip surface, 423 ... Third drilling bit, 424 ... Fourth drilling bit ..
10, 20, 30, 40 ... Steel pipe pile, 11 ... Steel pipe body, 11E ... End face, 12, 22, 32, 42 ... Excavation bit, 121, 121A, 221,221A, 321, 421 ... First excavation bit, 121E , 221E ... Tip surface, 122, 122A, 122B, 222, 222A, 222B, 322, 422 ... Second drilling bit, 122E, 222E ... Tip surface, 423 ... Third drilling bit, 424 ... Fourth drilling bit ..
Claims (12)
- 鋼管本体と、前記鋼管本体の端面に前記鋼管本体の周方向接線に対して角度をもって取り付けられ、前記鋼管本体の軸方向に突出する板状の掘削ビットとを備える鋼管杭であって、
前記掘削ビットが、
前記鋼管本体の端面から前記鋼管本体の軸方向に第1の高さだけ突出する第1の掘削ビットと、
前記鋼管本体の端面から前記鋼管本体の軸方向に前記第1の高さよりも高い第2の高さだけ突出する第2の掘削ビットと
を含む鋼管杭。 A steel pipe pile provided with a steel pipe body and a plate-shaped excavation bit that is attached to the end surface of the steel pipe body at an angle with respect to the circumferential tangent of the steel pipe body and projects in the axial direction of the steel pipe body.
The excavation bit
A first excavation bit protruding from the end face of the steel pipe body by a first height in the axial direction of the steel pipe body,
A steel pipe pile including a second excavation bit that protrudes from the end face of the steel pipe body by a second height higher than the first height in the axial direction of the steel pipe body. - 前記第1の掘削ビットまたは前記第2の掘削ビットの少なくともいずれかの先端面に、前記鋼管本体の径方向の内側から外側に向かって突出高さが高くなる傾斜が形成される、請求項1に記載の鋼管杭。 Claim 1 in which the tip surface of at least one of the first excavation bit or the second excavation bit is formed with an inclination in which the protruding height increases from the inside to the outside in the radial direction of the steel pipe body. Steel pipe pile described in.
- 前記第1の掘削ビットまたは前記第2の掘削ビットの少なくともいずれかが、前記鋼管本体の径方向の内側から外側に向かって厚くなるテーパー断面で形成される、請求項1または請求項2に記載の鋼管杭。 The first or second excavation bit, wherein at least one of the first excavation bit or the second excavation bit is formed in a tapered cross section that becomes thicker from the inside to the outside in the radial direction of the steel pipe body. Steel pipe pile.
- 前記掘削ビットが、前記鋼管本体の端面から前記鋼管本体の軸方向に前記第2の高さよりも高い第3の高さだけ突出する第3の掘削ビットをさらに含む、請求項1から請求項3のいずれか1項に記載の鋼管杭。 Claims 1 to 3 further include a third excavation bit in which the excavation bit protrudes from the end surface of the steel pipe body by a third height higher than the second height in the axial direction of the steel pipe body. The steel pipe pile according to any one of the above.
- 前記掘削ビットは、前記鋼管杭を先端側から見たときにC字状またはS字状になるように湾曲した板状である、請求項1から請求項4のいずれか1項に記載の鋼管杭。 The steel pipe according to any one of claims 1 to 4, wherein the excavation bit has a plate shape curved so as to have a C-shape or an S-shape when the steel pipe pile is viewed from the tip side. Pile.
- 前記掘削ビットは、前記鋼管本体の径方向の外側または内側の少なくともいずれかに突出し、
前記第1の掘削ビットは、前記鋼管本体の管厚中心線から前記鋼管本体の径方向に第1の距離だけ突出することによって第1の掘削可能領域を有し、
前記第2の掘削ビットは、前記鋼管本体の管厚中心線から前記鋼管本体の径方向に前記第1の距離よりも長い第2の距離だけ突出することによって、前記鋼管本体の径方向の外側または内側の少なくともいずれかで前記第1の掘削可能領域よりも拡張された第2の掘削可能領域を有する、請求項1から請求項5のいずれか1項に記載の鋼管杭。 The excavation bit protrudes at least either outward or inside in the radial direction of the steel pipe body.
The first excavation bit has a first excavable region by projecting from the pipe thickness center line of the steel pipe body by a first distance in the radial direction of the steel pipe body.
The second excavation bit protrudes from the pipe thickness center line of the steel pipe body by a second distance longer than the first distance in the radial direction of the steel pipe body, thereby extending the outside of the steel pipe body in the radial direction. The steel pipe pile according to any one of claims 1 to 5, which has a second excavable area that is expanded from the first excavable area at least on the inner side. - 前記第1の掘削ビットは、前記鋼管本体の周方向接線に対して第1の角度をもって取り付けられ、
前記第2の掘削ビットは、前記鋼管本体の周方向接線に対して前記第1の角度よりも大きい第2の角度をもって取り付けられる、請求項6に記載の鋼管杭。 The first excavation bit is attached at a first angle with respect to the circumferential tangent of the steel pipe body.
The steel pipe pile according to claim 6, wherein the second excavation bit is attached at a second angle larger than the first angle with respect to the circumferential tangent of the steel pipe body. - 前記第1の掘削ビットは、前記第1の掘削ビットの取り付け方向に沿って第1の長さを有し、
前記第2の掘削ビットは、前記第2の掘削ビットの取り付け方向に沿って前記第1の長さよりも長い第2の長さを有する、請求項6または請求項7に記載の鋼管杭。 The first excavation bit has a first length along the mounting direction of the first excavation bit.
The steel pipe pile according to claim 6 or 7, wherein the second excavation bit has a second length longer than the first length along the attachment direction of the second excavation bit. - 請求項1から請求項8のいずれか1項に記載された鋼管杭の施工方法であって、
前記鋼管杭の先端が所定の深度に到達するまで、前記掘削ビットが土砂を前記鋼管本体の外側に押し出す第1の回転方向に前記鋼管杭を回転させながら掘削する工程と、
前記鋼管杭の先端が打ち止め深さに到達するまで、前記掘削ビットが土砂を前記鋼管本体の内側に取り込む第2の回転方向に前記鋼管杭を回転させながら掘削する工程と
を含む鋼管杭の施工方法。 The method for constructing a steel pipe pile according to any one of claims 1 to 8.
A step of excavating while rotating the steel pipe pile in the first rotation direction in which the excavation bit pushes earth and sand to the outside of the steel pipe body until the tip of the steel pipe pile reaches a predetermined depth.
Construction of a steel pipe pile including a step of excavating the steel pipe pile while rotating the steel pipe pile in a second rotation direction in which the excavation bit takes in earth and sand inside the steel pipe body until the tip of the steel pipe pile reaches the stopping depth. Method. - 前記打ち止めの際に、前記鋼管杭の先端を支持層に到達させてから、前記鋼管杭を前記第2の回転方向に回転させる、請求項9に記載の鋼管杭の施工方法。 The method for constructing a steel pipe pile according to claim 9, wherein the tip of the steel pipe pile reaches the support layer at the time of stopping, and then the steel pipe pile is rotated in the second rotation direction.
- 前記打ち止めの際に、前記鋼管杭の先端が支持層に到達する直前から、前記鋼管杭を前記第2の回転方向に回転させながら掘削し、前記鋼管杭の先端が前記支持層に到達してから打ち止める、請求項9に記載の鋼管杭の施工方法。 At the time of the stop, immediately before the tip of the steel pipe pile reaches the support layer, the steel pipe pile is excavated while rotating in the second rotation direction, and the tip of the steel pipe pile reaches the support layer. The method for constructing a steel pipe pile according to claim 9, which is stopped from.
- 前記第1の回転方向に前記鋼管杭を回転させながら掘削する工程と、前記第2の回転方向に前記鋼管杭を回転させながら掘削する工程とが交互に実施される、請求項9から請求項11のいずれか1項に記載の鋼管杭の施工方法。
9 to claims, wherein the step of excavating while rotating the steel pipe pile in the first rotation direction and the step of excavating while rotating the steel pipe pile in the second rotation direction are alternately performed. The method for constructing a steel pipe pile according to any one of 11.
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