JP2013019249A - Rotating buried pile, burying construction method thereof, and underground burial structure flotation suppression device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating buried pile easy to be constructed and capable of surely suppressing flotation and subsidence of an underground burial structure, an aboveground structure, and the like, a burying construction method of the same, and an underground burial structure flotation suppression device.SOLUTION: A rotating buried pile comprises: a cylindrical pile body 10; a nearly one round of spiral blade 11 provided on a lower end side peripheral surface of the pile body 10; and two auxiliary boring blades 12 arranged at equal intervals along the circumferential direction of the spiral blade 11 and capable of radially protruding from the circumference of the spiral blade 11. The auxiliary boring blades 12 are pushed onto the circumference of the spiral blade 11 when rotating the pile body 10 in one direction (normal rotation) and moving (propelling) it in an underground burial direction, and the auxiliary boring blades 12 project from the circumference of the spiral blade 11 in the radial direction of the pile body 10 when rotating the pile body 10 in the other direction (reverse rotation) to pull it out from the underground.

Description

  The present invention is, for example, an anchor for preventing underground structures such as manholes from floating due to ground liquefaction, a building on soft ground, a support pile for preventing the ground structure from sinking, etc. The present invention relates to a rotary pile that can be used, a method for burying the pile, and a device for suppressing levitation of underground structures.

  The inventors have proposed one of the underground buried structure levitation suppression devices for suppressing the underground structures such as manholes from floating due to the ground liquefaction phenomenon (see Patent Document 1). According to this, a pair of structure fixing shafts in which a winged anchor provided with spiral wings on the peripheral surface of a cylindrical body is fixed to the lower end portion is placed in the ground near both ends in the diameter direction of the manhole so as to sandwich the manhole. Embed by rotating propulsion. Attach a ring-shaped fixing aid to the top of the manhole. And the upper end part of each structure fixing shaft is each fixed to the both ends of the diameter direction of a ring-shaped fixing auxiliary tool.

  According to the above underground buried structure floating restraint device, each winged anchor bites into the ground, so that even if ground liquefaction occurs due to an earthquake, the underground buried structure is reliably restrained from floating. I can.

  In addition to the above-mentioned underground structure floating control device, for example, an opening is opened at the bottom of a manhole, a hole reaching the non-liquefied layer of the ground from this opening is excavated, grout is injected into this excavation hole, anchor tensioning A material is inserted, the lower end of the anchor tensile material is fixed to the non-liquefied layer into which grout is injected, and the upper end of the anchor tensile material protruding from the opening is fixed to the bottom of the manhole (Patent Document) 2).

JP 2008-69557 A JP 2005-24896 A

  In the former case, the structure fixing shaft is embedded by rotating and propelling it in the ground near both ends of the manhole in the diametrical direction, so these pipes are installed in places where many pipes are embedded around the manhole. It must be avoided and construction may be difficult.

  In the latter case, the anchor tension member is inserted into the excavation hole from the opening opened at the bottom of the manhole, so that these pipes extend under the manhole bottom even in places where many pipes are embedded around the manhole. Unless it is possible to work without being obstructed by the piping around the manhole, the bottom of the anchor tension material is simply fixed to the non-liquefied layer into which grout has been injected. It is difficult to reliably suppress the rise of manholes due to the chemical phenomenon. It is also difficult to reliably suppress manhole settlement for the same reason.

  The present invention provides a rotary buried pile, a method for burying a buried underground, and a device for suppressing the rise of a buried underground structure, which is easy to construct and can reliably suppress the floating and subsidence of underground structures and ground structures. The purpose is to provide.

  The rotary buried pile according to claim 1 of the present invention is a tubular pile body provided with a drilling blade at the bottom of the lower end, a spiral wing provided on the lower end side peripheral surface of the pile body, and a periphery of the spiral wing. A plurality of auxiliary excavation blades arranged at predetermined intervals along the direction and capable of projecting in the radial direction of the pile main body from a peripheral edge of the spiral blades, and each of the auxiliary excavation blades When it is fixed so as to extend in the axial direction of the pile main body at the end portion of the support piece rotatably attached to the surface portion, and when the pile main body is rotated in one direction and moved in the direction of being buried in the ground, The auxiliary excavation blade does not protrude in the radial direction of the pile body, and the auxiliary excavation blade protrudes in the radial direction of the pile body when the pile body is rotated in the other direction and moved in the direction of extraction from the ground. It is characterized by doing.

According to a third aspect of the present invention, the rotary buried pile includes a tubular pile main body, a spiral blade provided on the lower end side peripheral surface of the pile main body, and a spiral blade periphery. A plurality of auxiliary excavation blades arranged at predetermined intervals along the direction and projecting in the radial direction of the pile body from the periphery of the spiral blade, and a grout ejection hole provided at the bottom bottom of the pile body. Each of the auxiliary excavation blades is fixed to the end of a support piece rotatably attached to the surface portion of the spiral wing so as to extend in the axial direction of the pile main body, and the pile main body is rotated in one direction to be ground. The auxiliary excavating blade does not protrude in the radial direction of the pile body when moving in the direction of embedding in the inside, and the auxiliary excavating blade is moved in the direction of extracting it from the ground by rotating the pile main body in the other direction. Configured to protrude in the radial direction of the body,
A grouting pipe is installed inside the pile body, and a preparation step for connecting the tip portion to the grouting hole,
The pile body is rotated in one direction and moved into the ground by the propulsive force of the spiral wing, and the bottom end of the pile body is a predetermined position in the ground (for example, from a predetermined depth at which the bottom bottom of the pile body is embedded). A rotary embedding step of moving the bottom bottom of the pile body to a predetermined depth while spouting the grout from the grout spout at the time of arriving at a meter to 2 meters before)
The pile body is rotated in the other direction opposite to the one direction while the grout is ejected from the grout outlet, and is pulled up from the predetermined depth to the predetermined position. A retreating step of further excavating the earth and sand around the spiral blade by projecting in the radial direction of the pile body from the periphery of the pile,
The rotary embedding step and the rotary retreating step are alternately repeated between the predetermined position and the predetermined depth to mix and agitate the sand and the grout excavated by the spiral blade and the auxiliary excavation blade. The mixing stirring step is repeated until the mixing stirring is repeated by the weight of the pile main body until the bottom bottom of the pile main body is lowered to the predetermined depth in the ground.

The embedding method for embedding the rotary buried pile according to claim 4 of the present invention includes a tubular pile body in which the rotary buried pile is provided with an excavating blade at the bottom end, and a lower end side circumference of the pile body. A spiral wing provided on the surface, and a grout ejection hole provided at the bottom of the lower end of the pile body, for ejecting the grout into the ground,
A grouting pipe is installed inside the pile body, and a preparation step for connecting the tip portion to the grouting hole,
The pile body is rotated in one direction and moved into the ground by the propulsive force of the spiral wing, and the bottom end of the pile body is a predetermined position in the ground (for example, from a predetermined depth at which the bottom bottom of the pile body is embedded). A rotary embedding step of moving the bottom bottom of the pile body to a predetermined depth while spouting the grout from the grout spout at the time of arriving at a meter to 2 meters before)
A rotational retreating step of rotating the pile main body in the other direction opposite to the one direction while pulling out the grout from the grout spout and pulling it up from the predetermined depth to the predetermined position;
The rotary embedding step and the rotary retreating step are alternately repeated between the predetermined position and the predetermined depth to excavate the spiral blade, and to mix and stir the excavated earth and sand and the grout. And a mixing and agitation step that repeats until the lower end bottom of the pile body descends to the predetermined depth in the ground by the weight of the pile body.

  The underground structure floating suppression apparatus according to claim 5 of the present invention is an underground structure floating suppression apparatus that suppresses the floating using an anchor in which the underground structure is embedded in the ground. The rotating buried pile buried under the bottom of the underground buried structure by the buried construction method according to claim 3 is used as the anchor, and the upper end of the anchor is connected to the underground buried structure by the connecting member. It connects with a bottom part, It is characterized by the above-mentioned.

  The underground structure floating suppression apparatus according to claim 6 of the present invention is an underground structure floating suppression apparatus that suppresses the floating using an anchor in which the underground structure is embedded in the ground. The rotating buried pile buried under the bottom of the underground buried structure by the buried construction method according to claim 4 is used as the anchor, and the upper end of the anchor is connected to the underground buried structure by the connecting member. It connects with a bottom part, It is characterized by the above-mentioned.

  According to the present invention, the construction is easy and can reliably suppress the floating and sinking of underground structures and ground structures.

It is the side view which abbreviate | omitted one part which shows one Example of the rotation embedding pile of this invention, and expressed the principal part with the perspective view. It is a partial expansion perspective view which shows the state which the auxiliary excavation blade provided in the spiral wing | blade of the rotary burying pile shown in FIG. 1 closed. It is a partial expansion perspective view which shows the state which the auxiliary excavation blade provided in the spiral wing | blade of the rotary burying pile shown in FIG. 1 opened. It is a figure which shows the auxiliary excavation blade and the support piece which attaches it to a spiral blade, (a) is a top view of an auxiliary excavation blade and a support piece, (b) is the same side view, (c) is the perspective view. It is the side view which abbreviate | omitted partially and showed the principal part with the perspective view which shows the other Example of the rotation embedding pile of this invention. It is the side view which abbreviate | omitted one part which shows another Example of the rotation embedding pile of this invention, and expressed the principal part with the perspective view. It is explanatory drawing which shows one Example of the embedding construction method of the rotation embedding pile of this invention. It is explanatory drawing which shows the other Example of the embedding construction method of the rotation embedding pile of this invention. It is the side view which partially cut and showed the principal part with the perspective view which shows one Example of the underground embedding structure floating suppression apparatus of this invention. It is a principal part expansion perspective view of the anchor part of the underground buoyant structure floating suppression apparatus shown in FIG. FIG. 10 is a partially enlarged partial side view illustrating a modification of the connection structure between the anchor main body upper end portion and the underground buried structure bottom portion of the underground buried structure floating suppression device illustrated in FIG. 9. FIG. 13 is a partially enlarged partial side view showing a modification of the connection structure shown in FIG. 11.

  FIG. 1 thru | or FIG. 4 (a), (b), (c) shows one Example of the rotation buried pile of this invention.

  The rotary buried pile according to the present embodiment includes a bowl-shaped pile body 10, a substantially one-turn spiral blade 11 provided on the lower end side peripheral surface of the pile body 10, and an equal interval along the circumferential direction of the spiral blade 11. And two auxiliary excavation blades 12 that can project from the peripheral edge of the spiral blade 11 in the radial direction of the pile body 10.

  The pile main body 10 is made of a steel pipe, and a bottom plate 13 is fixed to the bottom of the opened lower end. A tip excavation blade 14 is attached to the bottom plate 13 and a grout jet 15 is provided. At the time of construction, a grout injection pipe 60 is mounted in the pile body 10. The tip (not shown) of the grouting pipe 60 is connected to the grouting port 15. Grout (so-called cement milk, mortar, etc., which is made into a slurry by mixing cement powder and water in a predetermined ratio) sent from the grout injection pipe 60 is ejected from the grout outlet 15 to the excavated soil in the ground. The

  The spiral blade 11 has an outer diameter that is two to three times the outer diameter of the pile body 10. When the pile body 10 is rotated in one direction (forward rotation) by an auger (rotary push-in device), the spiral wing 11 is screwed into the ground to drive rotation, and the pile body 10 is brought into the ground while excavating and compressing the surrounding earth and sand. Promote.

  The auxiliary excavation blade 12 is fixed to the outer end portion of the support piece 16 rotatably attached to the surface portion of the spiral blade 11 so as to extend in the axial direction of the pile body 10. More specifically, a pair of support pieces 16 (see FIG. 4) that sandwich the front and back surfaces of the spiral blade 11 at positions near the periphery of the spiral blade 11 and that the inner end portion is rotatably attached to the spiral blade 11 via the pin 17. The auxiliary excavation blade 12 is fixed (welded) to the outer end of (a), (b), and (c) so as to extend in the axial direction of the pile body 10.

  The auxiliary excavation blade 12 rotates around the pin 17 by the earth and sand around the spiral blade 11 when the pile body 10 is rotated (forward) in one direction and moved (promoted) in the direction of being buried in the ground. And pressed against the periphery of the spiral blade 11. That is, the auxiliary excavation blade 12 does not protrude in the radial direction of the pile main body 10 from the spiral blade 11 when propelling the pile main body 10 into the ground, and stops at the accommodation position (see FIG. 2).

  Further, the auxiliary excavation blade 12 is pushed by the earth and sand around the spiral blade 11 when the pile body 10 is rotated (reversely rotated) in the other direction opposite to one direction and moved in the direction of extraction from the ground. Is pivoted in the opposite direction to the previous time, and protrudes in the radial direction of the pile body 10 from the periphery of the spiral blade 11 (see FIG. 3). Thereby, the auxiliary excavation blade 12 can further excavate the earth and sand around the spiral blade 10 that cannot be excavated by the spiral blade 10.

  The auxiliary excavation blades 12 may be one or three or more instead of two.

  When the pile body 10 is reciprocated up and down by repeating normal rotation and reverse rotation at a predetermined location in the ground, the excavation area at that location is expanded compared to other locations (locations excavated by only the spiral blade 11). It becomes possible.

  Although it is possible to enlarge the excavation area by increasing the diameter of the spiral blade 11, the excavation resistance is inevitably increased and the excavation efficiency is inevitably lowered. In the present embodiment, it is possible to expand the excavation area without increasing the diameter of the spiral blade 11, and even if excavation resistance, further excavation is performed by the auxiliary excavation blade 12 from the location already excavated by the spiral blade 11. Compared with the case where the diameter of 11 is increased and excavated, it is smaller. By mixing and stirring the earth and sand in the excavation area, cylindrical layers 50 and 50a (see FIGS. 7 and 8) of earth and sand hardened by the grout can be formed in the ground. The cylindrical layers 50 and 50a double the tip support force and the anti-pullout force of the pile body 10.

  The rotary buried pile of this embodiment can increase the tip support force and strengthen the pull-out force, and should be used as an anchor or support pile for underground structures such as manholes, buildings, and ground structures. Thus, the settlement and levitation of these structures can be reliably suppressed.

  5 and 6 show another embodiment of the rotary buried pile.

  The rotary buried pile shown in FIG. 5 is positioned above the spiral blade 11 of the pile body 10 (for example, within 500 mm from the spiral blade 11 and the cylindrical layer shown in FIGS. 7 and 8 after the rotary buried pile is buried in the ground. 50, 50a), the second spiral blade 18a is provided. The outer diameter of the second spiral blade 18a is larger than the spiral blade 11 (about 1.4 times), and is set to be substantially the same as when the auxiliary excavation blade 12 is deployed. In FIG. 5, the other portions have the same configuration as the rotary buried pile shown in FIG. 1, and therefore the same portions are denoted by the same reference numerals and description thereof is omitted.

  The rotary buried pile shown in FIG. 6 is configured by providing mixing stirring blades 18b at two locations above the spiral blade 11 of the pile body 10 (for example, a location 250 mm from the spiral blade 11 and a location 500 mm). These mixing stirring blades 18b are used to mix and stir the earth and sand and the grout together with the spiral blade 11 and the auxiliary excavation blade 12. In FIG. 6, the other parts have the same configuration as that of the rotary buried pile shown in FIG.

  As with the rotary buried piles of the present embodiment described above (FIG. 1 and the like), the tip support force and the anti-pullout force can be enhanced with respect to the rotary buried piles shown in FIGS. By using it as an anchor or support pile for underground structures, buildings, ground structures, etc., it is possible to reliably suppress the settlement and levitation of these structures, as well as the second spiral blade 18a and the mixing stirring blade It is possible to efficiently mix and agitate the earth and sand excavated in 18b.

  FIG. 7 shows an embodiment of the embedding method according to the present invention. According to the present embodiment, the rotary buried pile shown in FIG. 1 is used.

  First, the grout injection pipe 60 is mounted inside the pile main body 10, the tip end portion (not shown) is connected to the grout ejection hole 15, and the auger (rotary pushing device not shown) is connected to the upper end portion (top portion) of the pile main body 10. And the pile body 10 is erected at the burial site (preparation step).

  Next, when the pile main body 10 is rotated in one direction (forward rotation) by an auger (not shown), the tip excavation blade 14 is pushed into the ground of the buried portion, and the spiral blade 11 is bitten into the ground, the spiral blade 11 The pile main body 10 moves (promotes) into the ground by the propulsive force. At this time, the auxiliary excavation blade 12 is rotated about the pin 17 by the earth and sand around the spiral blade 11 and pressed against the periphery of the spiral blade 11. Then, when the bottom end of the pile body 10 arrives at a predetermined position in the ground, for example, a position 1 meter to 2 meters before the predetermined depth at which the bottom bottom portion of the pile body 10 is embedded, grout from the grout spout 15, for example, The bottom end of the pile body 10 is moved to a predetermined depth while jetting cement milk (rotation embedding step).

  Next, while the cement milk is ejected from the grout ejection port 15, the pile main body 10 is rotated (reversely rotated) in the other direction opposite to the previous time by an auger (not shown) and pulled up from a predetermined depth to a predetermined position. At the time of this lifting, each auxiliary excavation blade 12 is pushed out to the earth and sand around the spiral blade 11, and as a result, the support piece 16 rotates around the pin 17 as a fulcrum, and each auxiliary excavation blade 12 moves from the periphery of the spiral blade 11. The pile body 10 protrudes in the radial direction, and the soil around the spiral wing 11 is further excavated (rotational retreat process).

  Next, the forward and reverse rotation of the pile body 10 is repeated, and the pile body 10 is reciprocated up and down between a predetermined position and a predetermined depth (the rotation embedding process and the rotation retreating process are alternately repeated), and the spiral blade 11 The earth and sand excavated by the auxiliary excavation blade 12 and the cement milk are mixed and stirred by the spiral blade 11 and the auxiliary excavation blade 12. When the rotary buried pile shown in FIG. 5 is used, the second spiral blade 18a also mixes and stirs the earth and cement milk. When the rotary buried pile shown in FIG. 6 is used, the mixing stirring blade 18b also mixes and stirs earth and sand and cement milk. This is performed a plurality of times, for example, 4 to 5 times. Thereafter, the rotation of the pile body 10 is stopped, and the auger (rotary pushing device) is removed from the upper end portion of the pile body 10. It is checked whether or not the bottom end of the pile body 10 descends to a predetermined depth in the ground by the weight of the pile body 10. When mixing and stirring is not sufficient (when the bottom end of the pile body 10 does not fall to a predetermined depth in the ground due to the weight of the pile body 10), the top end of the pile body 10 is connected to the auger (rotary pushing device) again. The normal rotation and reverse rotation of the pile body 10 are repeated (mixing and stirring step).

  It waits for cement milk to harden, if the bottom end of the pile main body 10 falls to the predetermined depth in the ground by the weight of the pile main body 10 (cement milk hardening step). After a predetermined time, a cylindrical layer 50 of earth and sand hardened with cement milk is formed in the ground.

  According to the embedding method of the present embodiment, the columnar layer 50 of earth and sand hardened by cement milk developed a pair of auxiliary excavation blades 12 from the spiral blade 11 (a pair of auxiliary excavation from the periphery of the spiral blade 11). The pile body 10 has a diameter corresponding to the distance between the auxiliary excavating blades 12 when the blades 12 are protruded, and the bearing force and resistance of the pile body 10 obtained only by the spiral blades 11 that do not have the columnar layer 50. It is possible to double the pulling force. Further, the columnar layer 50 has a height corresponding to the distance between a predetermined position and a predetermined depth, and the pile main body 10 is strengthened even if a pressing force or a pulling force is repeatedly applied to the pile main body 10. It is possible to support. Furthermore, since it is not necessary to increase the diameter of the spiral blade 11 in order to increase the tip support force and the anti-pullout force, there is no possibility of reducing the burying efficiency.

  The above-described embedding method of the present embodiment shown in FIG. 7 is a method of embedding an underground structure such as a manhole or a building constructed on the ground, an anchor for suppressing the rising and sinking of the ground structure, a support pile, and the like. It can be applied to the anchors, support piles and other tip support force, anti-pull-out force to enhance the underground structure such as manholes, buildings built on the ground, ground structures and so on. It is possible to suppress it.

  FIG. 8 shows another embodiment of the embedding method of the present invention. According to the present embodiment, the rotary buried pile in which the auxiliary excavation blade 12, the support piece 16, and the pin 17 are omitted from the rotary buried pile shown in FIG. 6 is used.

  As in the case of the embodiment shown in FIG. 7, the grout injection pipe 60 is first installed in the pile main body 10, the tip end portion is connected to the grout ejection hole 15, and the pile main body 10 is connected to the upper end (top). An auger (rotary pushing device) is connected and the pile main body 10 is erected at the burial location (preparation step).

  Next, when the pile main body 10 is rotated in one direction (forward rotation), the tip excavation blade 14 is pushed into the ground of the buried portion, and the spiral blade 11 is bitten into the ground, the propulsive force of the spiral blade 11 causes the ground to enter the ground. Moving. Then, when the bottom end of the pile body 10 arrives at a predetermined position in the ground, for example, a position 1 meter to 2 meters before the predetermined depth at which the bottom bottom portion of the pile body 10 is embedded, grout from the grout spout 15, for example, The bottom end of the pile body 10 is moved to a predetermined depth while jetting cement milk (rotation embedding step). At this time, the mixing stirring blade 18b mixes and stirs the earth and sand excavated by the spiral blade 11 and the cement milk.

  Next, the cement body 10 is spouted from the grout spout 15 and the pile body 10 is rotated (reversely rotated) in the other direction opposite to the previous time to be pulled up from a predetermined depth to a predetermined position. At the time of this lifting, unlike the embodiment of FIG. 7, the soil around the spiral blade 11 is not further excavated, but the mixing agitating blade 18 b removes the soil and cement milk excavated by the spiral blade 11. Mix and stir (rotation backward step).

  Next, the forward and reverse rotation of the pile body 10 is repeated, and the pile body 10 is reciprocated up and down between a predetermined position and a predetermined depth (the rotation embedding process and the rotation retreat process are alternately repeated), and the spiral blade 11 The excavated and excavated earth and sand and cement milk are mixed and stirred by the spiral blade 11 and the mixing stirring blade 18b. This is performed a plurality of times, for example, 4 to 5 times. Thereafter, similarly to the embodiment of FIG. 7, the rotation of the pile body 10 is stopped, the auger (rotary pushing device) is removed from the upper end portion of the pile body 10, and the lower end bottom portion of the pile body 10 with its own weight. Is checked to see if it falls to a predetermined depth in the ground (mixing stirring step).

  It waits for cement milk to harden, if the bottom end of the pile main body 10 falls to the predetermined depth in the ground by the weight of the pile main body 10 (cement milk hardening step). After a predetermined time has elapsed, a cylindrical layer 50a of earth and sand hardened with cement milk is formed in the ground.

  According to the embedding method of the present embodiment, the columnar layer 50a of earth and sand hardened by cement milk has a diameter corresponding to the spiral blade 11 and corresponds to a distance between a predetermined position and a predetermined depth. Compared with the case of only the spiral blade 11 having a height and not having the cylindrical layer 50a, a large supporting force and frictional resistance can be obtained. In addition, the pile main body 10 can be firmly supported even if a pressing force or a pulling force repeatedly acts on the pile main body 10. Furthermore, there is no risk of reducing the burial construction efficiency.

  The above-described embedding method of the other embodiment shown in FIG. 8 is also the same as the embedding method shown in FIG. 7, the underground structure such as a manhole, the building constructed on the ground, and the floating and sinking of the ground structure. It can be applied to anchoring and anchoring piles for restraint, and it is built on underground structures such as manholes by enhancing the tip supporting force and anti-pullout force of anchors and supporting piles. It is possible to reliably suppress the rising and sinking of buildings and ground structures.

  9 and 10 show an embodiment of the underground structure floating suppression apparatus of the present invention.

  In the present embodiment, the case where it is applied to the manhole 20 as an underground structure is shown. The levitation suppression device of the present embodiment includes an anchor 30 embedded in the ground below the bottom of the manhole 20 and a connecting member 40 that connects the anchor 30 to the bottom of the manhole 20. In addition, the underground buried structure floating suppression apparatus of this invention is applicable also to underground buried structures other than a manhole.

  5 is used as the anchor 30, and the anchor 30 is buried in the ground by the burying method shown in FIG.

  As with the rotary buried pile shown in FIG. 5, the anchor 30 includes a steel pipe anchor main body 30 a, a spiral blade 31 provided on the lower end side peripheral surface of the anchor main body 30 a, and a circumferential direction of the spiral blade 31. Two auxiliary excavation blades 32 that are arranged at equal intervals and can protrude in the radial direction of the anchor main body 30a from the periphery of the spiral blade 31 are provided.

  A bottom plate 33 is fixed to the bottom end of the anchor main body 30a, a tip excavation blade 34 is attached to the bottom plate 33, and a grout spout 35 is provided.

  The auxiliary excavation blade 32 is fixed to the outer end portion of the support piece 36 that is rotatably attached to the surface portion of the spiral blade 31 so as to extend in the axial direction of the anchor main body 30a. Specifically, a pair of support pieces 36 (FIG. 10) having the inner and outer ends pivotably attached to the spiral blade 31 via pins 37 with the front and back surfaces of the spiral blade 31 sandwiched between the peripheral portions of the spiral blade 31. Auxiliary excavation blade 32 is fixed (welded) to the outer end of the pile body 10 so as to extend in the axial direction.

  The auxiliary excavation blade 32 does not protrude in the radial direction of the anchor main body 30a from the spiral blade 31 when propelling the anchor main body 30a into the ground, and stops at the accommodation position. Further, the auxiliary excavation blade 32 protrudes in the radial direction of the anchor main body 30a from the periphery of the spiral blade 31 when the anchor main body 30a is rotated (reversed) in the other direction and moved in the direction of extraction from the ground.

  A second spiral blade 38 is provided above the spiral blade 31 of the anchor body 30a. The outer diameter of the second spiral blade 38 is larger than that of the spiral blade 31 and is set to be approximately the same as when the auxiliary excavation blade 32 is deployed.

  The anchor 30 (anchor main body 30a) is embedded in the ground below the bottom of the manhole 20 by a construction method similar to the construction method shown in FIG. The anchor 30 (anchor body 30a) is held in the ground against the pulling force by the cylindrical layer 50b (see FIG. 10) of earth and sand hardened with cement milk formed at this time. After the anchor 30 is buried, the auger (rotary pushing device) is removed and the grout injection pipe is removed.

  The connecting member 40 includes a rectangular steel plate 42 having a hole 41 through which the upper end portion of the anchor main body 30a passes, and a fixing plate 43 fixed to the top of the anchor main body 30a protruding from the hole 41. An opening 21 is opened at the bottom of the manhole 20 at the time of construction, and the upper end portion of the anchor main body 30 a protruding into the manhole 20 through the opening 21 penetrates the hole 41 of the steel plate 42.

  The fixing plate 43 is fixed to the top of the anchor body 30a by welding or the like, and after fixing the fixing plate 43 to the steel plate 42 by welding or the like, the opening 21 is closed and the manhole 20 is covered so as to cover the steel plate 42 and the fixing plate 43. A mortar 44 is placed on the bottom of the mortar.

  According to the underground structure floating suppression apparatus of the present embodiment, the anchor 30 is embedded in the ground below the bottom of the manhole 20 (substantially directly below the manhole 20). Even if the pipe is buried, the pipe is not obstructed unless the pipe extends directly under the manhole 20, so that the construction can be easily performed. Further, the anchor 30 (anchor main body 30a) is held in the ground against the pulling force by a cylindrical layer 50b (see FIG. 10) of earth and sand hardened with cement milk. It is possible to reliably suppress the 20 from floating. Further, the settlement of the manhole 20 can be reliably suppressed.

  FIG. 11 shows a modified example of the connecting member 40 of the underground structure floating suppression apparatus shown in FIG.

  According to this modification, the connecting screw shaft 45 is fixed to the upper end portion of the anchor main body 30a with a nut or welding. The connecting screw shaft 45 passes through a hole (not shown) in a rectangular steel plate 46 disposed in the manhole 20 through an opening 21 formed in the bottom of the manhole 20. The washer 47 is fitted to the upper end portion of the connecting screw shaft 45 penetrating the hole, and the nut 48 is screwed and fixed to the steel plate 46, thereby connecting the upper end portion of the anchor body 30a to the bottom portion of the manhole 20. After this connection, a mortar 49 is placed at the bottom of the manhole 20 so as to close the opening 21 and cover the steel plate 46, washer 47 and nut 48.

  FIG. 12 shows a modification of the connecting member 40 shown in FIG.

  According to this modification, instead of screwing the nut 48 to the connecting screw shaft 45 on the surface side of the steel plate 46a, the nut 48 is fixed to the back surface of the steel plate 46a in advance by welding or the like, and the steel plate 46a itself is turned. A nut 48 is screwed onto the connecting screw shaft 45.

  In addition, although not shown in figure, as one Example of the underground structure floating | floating suppression apparatus of this invention of Claim 6, for example, the rotation embedded in the ground under the bottom of a manhole by the burying construction method shown in FIG. The buried pile 10 is used as an anchor. Even in this case, the upper end of the anchor is connected to the bottom of the manhole by the connecting member 40 shown in FIG. 9, FIG. 11 or FIG.

  In this case as well, anchors are embedded in the ground below the bottom of the manhole (substantially below the manhole), so as long as the pipe does not extend directly under the manhole, even if pipes are buried around the manhole. Construction is easy without being disturbed by these pipes. In addition, the anchor (anchor body) is held in the ground against the pulling force by a cylindrical layer of earth and sand hardened with cement milk, so that the manhole is reliably prevented from floating due to the ground liquefaction phenomenon I can do it. In addition, manhole settlement can be reliably suppressed.

  The rotary buried pile and its construction method of the present invention are applied to suppress the floating and sinking of underground structures such as manholes, buildings, and ground structures.

DESCRIPTION OF SYMBOLS 10 Pile main body 11 Spiral blade 12 Auxiliary excavation blade 13 Bottom plate 14 Tip excavation blade 15 Grout spout 16 Support piece 17 Pin 18a Spiral blade 18b Mixing stirring blade 20 Manhole (underground structure)
30 Anchor 40 Connecting member 50 Cylindrical layer of earth and sand hardened by cement milk 50a Cylindrical layer of earth and sand hardened by cement milk 50b Cylindrical layer of earth and sand hardened by cement milk

Claims (6)

Tubular pile body with a drilling blade at the bottom of the bottom,
A spiral wing provided on the lower peripheral surface of the pile body;
A plurality of auxiliary excavation blades arranged at predetermined intervals along the circumferential direction of the spiral wing and capable of projecting in the radial direction of the pile body from the periphery of the spiral wing,
Each of the auxiliary excavation blades is fixed to the end portion of the support piece rotatably attached to the surface portion of the spiral wing so as to extend in the axial direction of the pile body,
When the pile body is rotated in one direction and moved in the direction of being buried in the ground, the auxiliary excavation blade does not protrude in the radial direction of the pile body,
When rotating the said pile main body to another direction and moving it in the direction extracted from underground, the said auxiliary excavation blade protrudes in the radial direction of the said pile main body, The rotary buried pile characterized by the above-mentioned. In the rotary buried pile according to claim 1,
A rotary buried pile characterized in that a grout ejection hole for ejecting grout from a grout injection pipe into the ground is provided at the bottom of the bottom of the pile body. An embedding method for burying a rotating buried pile in the ground,
The rotating buried pile has a tubular pile main body provided with an excavating blade at the bottom of the lower end, a spiral wing provided on the lower end side peripheral surface of the pile main body, and a predetermined interval along the circumferential direction of the spiral wing. A plurality of auxiliary excavation blades that are arranged open and projectable in the radial direction of the pile main body from the periphery of the spiral wing, and a grout ejection hole provided in a bottom end of the pile main body, and the auxiliary excavation Each of the blades is fixed to the end portion of the support piece rotatably attached to the surface portion of the spiral wing so as to extend in the axial direction of the pile body, and the pile body is rotated in one direction into the ground. When moving in the direction of burying, the auxiliary excavation blade does not protrude in the radial direction of the pile main body, and when moving the pile main body in the other direction and moving it in the direction of extracting from the ground, the auxiliary excavation blade Is configured to protrude in the radial direction of the pile body,
A grouting pipe is installed inside the pile body, and a preparation step for connecting the tip portion to the grouting hole,
The pile body is rotated in one direction and moved into the ground by the propulsive force of the spiral wing, and when the bottom end of the pile body arrives at a predetermined position in the ground, the grout is ejected from the grout outlet. A rotational embedding step of moving the bottom end of the pile body to a predetermined depth;
The pile main body is rotated in another direction opposite to the one direction while the grout is ejected from the grout outlet, and is pulled up from the predetermined depth to the predetermined distance position. A rotary retreating step of further excavating the soil around the spiral wing by projecting in the radial direction of the pile body from the periphery of the wing;
The rotary embedding step and the rotary retreating step are alternately repeated between the predetermined position and the predetermined depth to mix and agitate the sand and the grout excavated by the spiral blade and the auxiliary excavation blade. And a mixing and stirring step of repeating this mixing and stirring until the bottom bottom of the pile body descends to the predetermined depth in the ground by the weight of the pile body. An embedding method for burying a rotating buried pile in the ground,
The rotary buried pile is provided with a tubular pile body provided with a drilling blade at the bottom bottom, a spiral wing provided on a lower peripheral surface of the pile body, a bottom bottom of the pile body, and a grout. A grouting hole that erupts inside,
A grouting pipe is installed inside the pile body, and a preparation step for connecting the tip portion to the grouting hole,
The pile body is rotated in one direction and moved into the ground by the propulsive force of the spiral wing, and when the bottom end of the pile body arrives at a predetermined position in the ground, the grout is ejected from the grout outlet. A rotational embedding step of moving the bottom end of the pile body to a predetermined depth;
A rotational retreating step of rotating the pile main body in another direction opposite to the one direction while ejecting the grout from the grout outlet, and pulling it up from the predetermined depth to the predetermined distance position;
The rotary embedding step and the rotary retreating step are alternately repeated between the predetermined position and the predetermined depth to excavate the spiral blade, and to mix and stir the excavated earth and sand and the grout. And a mixing and agitation step that repeats until the bottom end of the pile body descends to the predetermined depth in the ground by the weight of the pile body. An underground buried structure levitation suppression device that suppresses its levitation using an anchor embedded in the underground structure,
Using the rotating buried pile buried under the bottom of the underground buried structure by the buried construction method according to claim 3 as the anchor,
An underground buried structure levitation suppression apparatus, wherein an upper end portion of the anchor is connected to a bottom portion of an underground buried structure by a connecting member. An underground buried structure levitation suppression device that suppresses its levitation using an anchor embedded in the underground structure,
A rotary buried pile buried under the bottom of the underground buried structure by the buried construction method according to claim 4 is used as the anchor,
An underground buried structure levitation suppression apparatus, wherein an upper end portion of the anchor is connected to a bottom portion of an underground buried structure by a connecting member.

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