JP2009013615A - Construction method for prefabricated pile, and foundation bearing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method for a prefabricated pile which can drive the prefabricated pile into the bearing ground in a space-saving manner at the downside of an already-constructed foundation, and can provide a rehabilitation method exhibiting high reliability over a long period of time against differential settlement, and to provide a foundation bearing structure using the prefabricated pile. <P>SOLUTION: This construction method for the prefabricated pile 1 comprises: a first step of forming a working space 70 by excavating the ground on the downside of the foundation 8; a second step of driving the prefabricated pile 1 into the ground while rotating it by connecting a jack 9, a direct-acting rotational transform mechanism 10 and the prefabricated pile 1 to the foundation 8 in a vertical direction 75 and driving the jack 9 in the working space 70; a third step of connecting the upper end of the prefabricated pile 1 driven into the ground, and the foundation 8 to each other by detaching the jack 9 and the direct-acting rotational transform mechanism 10; and a fourth step of backfilling the working space 70. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for constructing a ready-made pile placed on the lower side of a foundation, and a support structure for a foundation supported by the ready-made pile.

  Buildings such as houses are supported by foundations built on the ground. When a building is built on a soft ground, part or all of the foundation may sink due to the weight of the building and the foundation. In this way, when the foundation sinks after the building is built, it is called uneven settlement. If a part of the foundation sinks into the ground due to uneven settlement and the building tilts, the building must be restored horizontally.

  Conventionally, as a method of repairing a non-settled building, there is a method in which a jack or the like is interposed between the foundation and the building and the jack is used to lift the building by the amount of non-sinking with respect to the foundation. Moreover, there exists a method of lifting a building with a jack etc. with a foundation (for example, patent document 1).

  In addition, there is a method of excavating the lower side of the foundation that has subsided and driving a new pile (paragraph “0007” of Patent Document 2). Since the foundation and the building exist on the upper side, the pile is driven by using a jack between the pile and the foundation and using the load on the foundation and the building as a reaction force.

JP 2000-328591 A JP-A-10-18311

  In the method of lifting a building or foundation by a jack or the like, if the uneven settlement further proceeds, it is necessary to repair it again. However, it is difficult to accurately determine whether or not the uneven settlement has ended, and if the building is tilted, it is necessary to repair the inclination of the building regardless of whether or not the uneven settlement has ended.

  On the other hand, in the method of driving a new pile and supporting the foundation, the foundation is supported by the pile, so that the restored building does not tilt again. However, since the pile is driven using the building and foundation load as a reaction force on the lower side of the already constructed foundation, there is a disadvantage in that the pile driving force depends on the building and foundation load. For example, in the case of a house with a total load of about 50 t, the load that can be used as a reaction force for driving a pile is about 8 t. When the pile is driven to the support ground, if the pile is blocked by a stone or other obstacle, the obstacle can be crushed or pushed to obtain the force to drive the pile further. As a result, the pile may not be driven to the support ground. If the foundation is supported by a pile that does not reach the supporting ground, the building may tilt again due to further progress of the uneven settlement.

  The present invention has been made in view of such circumstances, and it is possible to drive a ready-made pile to a supporting ground in a space-saving manner under a foundation that has already been constructed. It aims at providing the construction method of the ready-made pile which can implement | achieve a highly reliable restoration method, and the foundation support structure by the ready-made pile.

  (1) The method for constructing a ready-made pile according to the present invention includes a first step of excavating the ground below the foundation to form a work space, and a jack, a linear motion rotation conversion mechanism on the foundation in the work space. , And connecting the ready-made pile in the vertical direction and driving the jack, the second step of driving the ready-made pile into the ground while rotating the ready-made pile, removing the jack and the linear motion rotation converting mechanism, and driving into the ground. A third step of connecting the upper end of the ready-made pile and the foundation, and a fourth step of refilling the work space.

  This ready-made pile construction method is used for foundations that support already built buildings. In the first step, the ground below the foundation to be supported by the ready-made piles is excavated. Thereby, the working space for an operator to implement the following 2nd process and 3rd process below is formed in the lower side of a foundation. In the second step, the jack, the linear motion rotation conversion mechanism, and the ready-made pile are connected to the bottom surface of the foundation in the vertical direction. And if a jack is driven, the load of a foundation and a building will be transmitted to a ready-made pile as rotation pushing force by a linear motion rotation conversion mechanism with extension of a jack. Thereby, the ready-made pile is pushed into the ground while rotating. By rotating the ready-made pile, the peripheral surface of the ready-made pile and the ground are cut off, and the ready-made pile is easily driven. Moreover, if the wing | blade is provided in the front-end | tip of a ready-made pile, the propulsive force of a perpendicular direction can also be provided to a ready-made pile by rotation of the wing | blade. Furthermore, it becomes possible to push the obstacle in the ground by driving the ready-made pile a little and then driving it again.

  In the second step, after the ready-made pile is driven into the ground to a predetermined depth, the third step is performed. In the third step, the linear motion rotation conversion mechanism provided between the jack and the ready-made pile is removed. And the upper end of the ready-made pile and a foundation are connected. This connection can be performed using, for example, a fixing bracket as described later. If the foundation or the building is inclined, the inclination may be repaired in the third step. Thereby, the foundation and the building are leveled, and the foundation is supported by the ready-made pile. In the fourth step, the work space is backfilled. Further, if necessary, concrete may be placed around the foundation.

  (2) As the linear motion rotation converting mechanism, a spiral groove traveling in the extending direction is formed on the outer periphery, and connected to the jack with a spiral member having a connecting portion with the ready-made pile at one end in the extending direction. A first coupling portion and a second coupling portion to which the spiral member is coupled are mutually rotatable about a coupling direction, and the extending direction is engaged with the spiral groove with the extending direction as a vertical direction. A support member that supports the spiral member at a predetermined position and that can advance and retract in the vertical direction while rotating the spiral member along the spiral groove may be used.

  The spiral member is supported at a predetermined height position in the work space by the support member. The upper end of the spiral member is connected to a jack via a joint. The lower end of the spiral member is connected to a ready-made pile to be driven. When the jack is driven, the joint and the spiral member move downward as the jack extends. When the spiral member advances and retreats with respect to the support member, the spiral member 11 rotates along the spiral groove by the engagement between the spiral groove of the spiral member and the support member. The rotation and movement of the spiral member are transmitted to the ready-made pile, and the ready-made pile is driven into the ground while being rotated. Further, the jack does not rotate with the rotation of the spiral member due to the joint. Thereby, a linear motion rotation conversion mechanism can be realized in a simple and space-saving manner in the work space.

  (3) In the second step, a pre-made pile having a predetermined length may be driven into the ground while adding.

  In order to bring a ready-made pile into the work space, the length of the ready-made pile must be shorter than the height of the work space. On the other hand, the depth of the support ground to reach the ready-made piles is often deeper than the height of the work space. Therefore, in order to allow the ready-made piles to reach the support ground, it is preferable to add a plurality of ready-made piles having a length that can be brought into the work space and drive them into the ground.

  (4) In the second step, every time the jack is driven to reciprocate once, the temporary pile is already replaced with a temporary pile having a length corresponding to (the number of times the jack is reciprocated) × (jack stroke). After temporarily driving to the ready-made pile that has been driven and driving the jack, the jack may be driven a plurality of times corresponding to the length of the ready-made pile to be added, and then the ready-made pile may be added instead of the temporary pile. .

  The stroke of the jack is often shorter than the length of a single ready-made pile that is used in conjunction. If the length of one ready-made pile is made about the stroke of the jack, the work of adding will increase and the work will be complicated. On the other hand, the ready-made pile cannot be driven into the ground more than the stroke for one reciprocating drive of the jack. Therefore, when the jack is driven to reciprocate once, the temporary pile having a length corresponding to one stroke of the jack is temporarily joined to the upper end of the ready-made pile. Subsequently, when the jack is driven to reciprocate once, the temporary pile having a length corresponding to two strokes of the jack is temporarily connected to the upper end of the ready-made pile instead of the temporary pile described above. And this is repeated and a jack is reciprocated several times. The number of times the jack is reciprocated corresponds to the length of the ready-made pile. That is, the jack is reciprocally driven by the number obtained by dividing the length of the ready-made pile by the stroke of the jack. Then, since the space of the length of one ready-made pile is made between the upper end of the driven ready-made pile and a jack, it can replace with a temporary pile and can add a ready-made pile. In addition, the temporary pile can be used again until the next ready-made pile is added.

  (5) In the third step, a pile head member having a cylindrical body loosely fitted to the upper end portion of the ready-made pile and a flat plate connected to the upper end of the cylindrical body, the flat plate with respect to the lower surface of the foundation You may connect with the upper end part of a ready-made pile as parallel, and may connect the said flat plate and the lower surface of the said foundation using a fixing metal fitting.

  The ready-made pile driven into the ground does not necessarily match the vertical direction of the axial direction. Therefore, the cylinder body of the pile head member is loosely fitted to the upper end of the ready-made pile, and the flat plate on the upper surface of the cylinder body is positioned so as to be parallel to the lower surface of the foundation. At that position, the pile head member is fixed to the ready-made pile. Thereby, since the flat plate of a pile head member and the lower surface of a foundation become parallel, these can be simply and reliably connected with a fixture.

  (6) The present invention can be understood as a foundation support structure in which a foundation of a building is supported on a ready-made pile placed on the ground by the method described above.

  According to the present invention, a jack, a linear motion rotation conversion mechanism, and a ready-made pile are connected to the bottom surface of the foundation in the vertical direction, and the load of the foundation and the building due to the drive of the jack is rotated and pushed by the linear motion rotation conversion mechanism. Since it is transmitted to the ready-made pile, it becomes easy to drive the ready-made pile into the ground. As a result, it is possible to drive the ready-made pile to the support ground by effectively utilizing the limited load, and a long-term reliable repair method is realized against the uneven settlement.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. In addition, this embodiment is only an example of this invention, and it cannot be overemphasized that embodiment can be changed suitably in the range which does not change the summary of this invention.

  FIG. 1 is a perspective view showing a ready-made pile 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a construction method of the ready-made pile 1 in the work space 70. FIG. 3 is a perspective view showing the configuration of the spiral member 11. FIG. 4 is a longitudinal sectional view showing the internal configuration of the joint 12. FIG. 5 is a schematic view showing a state in which the pile head member 50 and the fixture 51 are assembled. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 to FIG. 9 are schematic diagrams for explaining each process in the method for constructing a ready-made pile. FIG. 10 is a schematic diagram showing a state in which the axial direction 74 of the ready-made pile 1 is inclined with respect to the vertical direction 75. FIG. 11 is a perspective view showing a restraining member 48 according to a modification of the present embodiment. In addition, the pile tip member 3 of the ready-made pile 1 is abbreviate | omitted in FIG. Moreover, in FIGS. 7-9, the foundation 8 and a part of support member 13, and the pile tip member 3 are abbreviate | omitted.

The construction method of the ready-made pile demonstrated in this embodiment includes the following each process.
(1) First step of excavating the lower ground of the foundation 8 to form the work space 70 (2) In the work space 70, the jack 9, the linear motion rotation conversion mechanism 10, and the ready-made pile 1 are attached to the foundation 8. Second step of driving the ready-made pile 1 while rotating the ready-made pile 1 by connecting to the vertical direction 75 and removing the jack 9 and the linear motion rotation converting mechanism 10 and rotating the ready-made pile 1 into the ground. The third step of connecting the upper end of 1 and the foundation 8 (4) The fourth step of refilling the work space 70 The method for constructing this ready-made pile is to convert the load of the foundation 8 and the building by the drive of the jack 9 into the linear motion rotation. The mechanism 10 is characterized in that it is transmitted to the ready-made pile 1 as a rotational pushing force.

  Below, each member used in this construction method is explained in detail.

[Pre-made pile 1]
As shown in FIG. 1, the ready-made pile 1 has a pile tip member 3 provided at a tip portion of a pile body 2. The pile main body 2 has a predetermined length and is joined to a necessary length at a construction site. The pile main body 2 and the pile tip member 3 are configured as separate members and can be easily attached at a construction site.

  The pile main body 2 is a steel pipe having a square cross-sectional shape perpendicular to the direction of the axis 74 (vertical direction in FIG. 1). Although the length of the axial direction of the pile main body 2 is not specifically limited, For example, when using the ready-made pile 1 in order to support the foundation of a house, the thing of about several meters to 20 meters is utilized. . Each pile body 2 has a length of, for example, about several meters, and several pile bodies 2 are joined on the coaxial line by welding with the upper and lower ends in contact. The external dimensions and thickness of the pile body 2 are not particularly limited. For example, when the ready-made pile 1 is used to support the foundation of a house, one side is about 10 centimeters to several tens of centimeters. The one with a wall thickness of several millimeters is used. Moreover, if the square pipe (steel pipe) marketed for a general purpose is used as the pile main body 2, it is suitable from cost and easy procurement.

  The pile tip member 3 includes a cylindrical body 5 fitted on the tip of the pile body 2, a spiral blade 6 provided on the outer periphery of the cylindrical body 5, and an excavation claw 7 provided on the tip of the cylindrical body 5. To do. A cylindrical body 5 of a pile tip member 3 is fitted on the tip of the pile body 2 and is fixed to the pile body 2 by fixing with bolts and deformation by caulking. Thereby, the ready-made pile 1 of the shape from which the spiral blade 6 of the pile tip member 3 protruded in the substantially horizontal direction at the front-end | tip part of the pile main body 2 is obtained.

  In addition, the cross-sectional external shape of the pile main body 2 is not necessarily limited to a square, and may be another polygonal shape or a circular shape, but there is little soil adhering to the periphery of the pile main body 2 when the ready-made pile 1 is constructed, The cross-sectional outer shape is preferably polygonal because resistance to penetration into the ground is reduced. Moreover, although the pile tip member 3 is arbitrary structures, since the propulsive force at the time of rotationally penetrating the ready-made pile 1 is obtained by providing the pile tip member 3, it is preferable.

[Linear rotation conversion mechanism 10]
As shown in FIG. 2, the linear motion rotation conversion mechanism 10 includes a spiral member 11, a joint 12, and a support member 13 as main components. The linear motion rotation conversion mechanism 10 transmits the linear motion of the jack 9 connected to the lower surface of the foundation 8 to the ready-made pile 1 as linear motion and rotational motion. A spiral member 11 is connected to the lower side of the jack 9 via a joint 12, and the ready-made pile 1 is connected to the lower side of the spiral member 11. These connections are substantially along the vertical direction 75 (vertical direction in FIG. 2). The spiral member 11 is supported at a predetermined height by the support member 13 and can advance and retreat in the vertical direction 75.

  As shown in FIG. 3, the spiral member 11 mainly includes a spiral portion 20 having spiral grooves 21 and 22 and connecting portions 23 and 24 provided at upper and lower ends of the spiral portion 20, respectively. The spiral portion 20 is formed by twisting a strip-shaped steel plate having a constant width with the length direction as an axial direction. Thereby, spiral grooves 21 and 22 are formed on the front and back sides of the steel plate, respectively. The spiral grooves 21 and 22 advance while forming a spiral at an angle of 45 ° in the length direction of the steel plate. In FIG. 3, the vertical direction of the spiral portion 20 is referred to as an extending direction in the present invention. Each spiral groove 21 and 22 is a groove having a constant width by being surrounded by both ends of the steel plate. The openings of the spiral grooves 21 and 22 are exposed on the outer peripheral side of the spiral portion 20. Restraint rods 43 and 44, which will be described later, are fitted into the spiral grooves 21 and 22, respectively, from the outer peripheral side. It should be noted that the angle at which the spiral grooves 21 and 22 are twisted with respect to the extending direction is not limited to 45 °, and it goes without saying that a suitable angle is set according to the embodiment.

  A connecting portion 23 is provided at the upper end of the spiral portion 20. The connection part 23 is a member for ensuring the connection with the joint 12, and a disk-shaped steel plate is used in this embodiment. The front and back surfaces of the disk are arranged so as to be orthogonal to the extending direction, and are fixed to the upper end of the spiral portion 20 by welding to constitute a connecting portion 23.

  A connecting portion 24 is provided at the lower end of the spiral portion 20. The connection part 24 is a member for ensuring connection with the ready-made pile 1, and in this embodiment, a disk-shaped steel plate and a square steel pipe are used. Similar to the connecting portion 23, the disk is arranged so that the front and back surfaces thereof are orthogonal to the extending direction, and is fixed to the lower end of the spiral portion 20 by welding. A steel pipe is fixed to the lower side of the disk by welding so that the extending direction of the spiral portion 20 matches the axial direction. This steel pipe is an insertion portion 25 that is inserted into the upper end of the pile body 2 of the ready-made pile 1. The fitting portion 25 has the same cross-sectional outer shape as the pile main body 2 and has an outer dimension that can be fitted into the inner space of the pile main body 2. When the fitting portion 25 is fitted into the pile main body 2, the rotational motion is transmitted from the fitting portion 25 to the pile main body 2 by the mutual fitting. On the other hand, the upper end of the pile body 2 comes into contact with the disk of the connecting portion 24. By this contact, a downward pushing force (linear motion) is transmitted from the spiral member 11 to the pile body 2.

  As shown in FIG. 4, the joint 30 mainly includes a joint main body 31, two connecting plates 32 and 33, and an iron ball 29. The joint body 31 is a steel pipe having a circular cross-sectional shape, and a partition plate 34 that closes the inner space of the steel pipe is provided at the center in the axial direction. The joint body 31 can be inserted into the base plate of the jack 9 and the connecting portion 23 of the spiral member 11 up to the vicinity of the partition plate 34 and the jack 9 and the connecting portion 23 are not displaced from the axial direction. There is no particular limitation. The partition plate 34 is a disk that matches the inner space of the steel pipe that constitutes the joint body 31, and a hole 37 through which the bolt 35 is inserted is penetrated in the center in the thickness direction. The partition plate 34 has a plurality of holes 38 penetrating in the thickness direction independently of each other. One iron ball 29 is fitted into each of the holes 38. A part of each iron ball 29 fitted in the hole 38 projects in the vertical direction from the partition plate 34.

  Two connecting plates 32 and 33 are disposed so as to sandwich the partition plate 34 in which the iron balls 29 are disposed in the holes 38 from above and below. The two connecting plates 32 and 33 each have a disk shape whose radial dimension is slightly shorter than that of the partition plate 34. In the present embodiment, the connection plate 32 is disposed on the upper side of the partition plate 34 and connected to the jack 9, and the connection plate 32 is disposed on the lower side of the partition plate 34 and connected to the spiral member 11. Therefore, the connecting plate 32 corresponds to the first connecting portion in the present invention, and the connecting plate 33 corresponds to the second connecting portion in the present invention.

  In the center of the coupling plates 32 and 33, holes 39 and 40 through which the bolts 35 are inserted are respectively penetrated in the thickness direction. Bolts 35 are inserted into holes 39 and 40 of the connection plates 32 and 33 and holes 37 of the partition plate 34, and nuts 36 are screwed into the bolts 35, so that the connection plates 32 and 33 are attached to the partition plate 34. It is fixed against. In this fixed state, the connecting plates 32 and 33 are rotatable about the bolt 35 as an axis. The axial direction of the bolt 35 corresponds to the connecting direction in the present invention. Further, the respective iron balls 29 fitted in the holes 38 of the partition plate 34 are in contact with the connecting plates 32 and 33 on the upper and lower sides thereof and can rotate smoothly. By the rotation of the iron ball 29, the connecting plates 32 and 33 rotate smoothly with each other.

  As shown in FIG. 2, the support member 13 includes two support columns 41 and 42 erected between the lower surface of the foundation 8 and the excavated ground, and two support members 13 and 42 installed between the support columns 41 and 42. And the restraining rods 43 and 44 (see FIG. 3). In FIG. 2, the two restraining bars 43 and 44 are arranged side by side in a direction perpendicular to the paper surface, so that the restraining bar 44 does not appear.

  The two columns 41 and 42 are erected in the vertical direction 75 on the base plate 45 with a predetermined interval. The base plate 45 is a flat steel plate laid on the excavated ground, and although not shown in FIG. 2, a hole through which the ready-made pile 1 can be inserted is penetrated in the thickness direction. Two struts 41 and 42 are separated so as to sandwich the hole. The height of each of the columns 41 and 42 is equal to the height from the excavated ground to the lower surface of the foundation 8, but the jack bases 46 and 47 are provided with the columns 41 and 42 so that the height can be adjusted slightly. It is provided on the lower end side of.

  Although not shown in detail in FIG. 2, two restraint bars 43 and 44 can be inserted in a predetermined height position of each of the columns 41 and 42 in a state of being parallel to the horizontal direction (see FIG. 3). Holes are formed. The height of the hole corresponds to the height at which the spiral member 11 is disposed, but a plurality of holes are formed in the vertical direction 75 in each of the columns 41 and 42 so that the height can be changed as necessary. It may be formed at a predetermined interval.

  The two restraining rods 43 and 44 are cylindrical rods having a thickness that can be fitted in the spiral grooves 21 and 22 of the spiral member 11 arranged along the vertical direction 75 in the horizontal direction. is there. The lengths of the restraining bars 43 and 44 are longer than the distance between the two support columns 41 and 42. Both ends of each of the restraining rods 43 and 44 are inserted into the holes of the columns 41 and 42, respectively. Male screws are formed at both ends of the restraining rods 43, 44, and nuts are screwed into the male screws, whereby both ends of the restraining rods 43, 44 are fastened to the columns 41, 42. As a result, as shown in FIGS. 2 and 3, the two restraining bars 43, 44 are arranged in a horizontal direction and arranged at a predetermined height.

  The distance between the two restraining rods 43 and 44 is determined corresponding to the spiral grooves 21 and 22 of the spiral member 11. Specifically, as shown in FIG. 3, the two restraining rods 43 and 44 are fitted in and engaged with the spiral grooves 21 and 22, respectively. As a result, the spiral member 11 is sandwiched and supported by the two restraining rods 43 and 44. In this state, the spiral member 11 is stationary unless an external force is positively applied. When a positive external force is applied to the spiral member 11 downward in the vertical direction like the pushing force by the jack 9, the spiral member 11 moves downward between the two restraining rods 43 and 44. During this movement, the spiral member 11 is rotated along the spiral grooves 21 and 22 by the restraining rods 43 and 44 fitted in the spiral grooves 21 and 22. In this way, the spiral member 11 supported at a predetermined height by the restraining rods 43 and 44 can advance and retreat in the vertical direction 75 while rotating along the spiral grooves 21 and 22.

[Jack 9]
As the jack 9, a known jack such as a hydraulic jack or a mechanical jack can be used, but a pump-separated hydraulic jack is preferable. Since the structure of such a jack is well known to those skilled in the art, a detailed description is omitted here.

[Pile head member 50]
As shown in FIG. 5, the ready-made pile 1 driven into the ground is connected to the foundation 8 by a pile head member 50 and a fixing bracket 51. The pile head member 50 includes a cylindrical body 52 and a flat plate 53 as main components. The cylindrical body 52 is a circular steel pipe whose cross-sectional shape is sufficiently larger than the outer shape of the pile body 2 of the ready-made pile 1. Specifically, the inner diameter of the cylinder 52 is larger than the diagonal dimension in the square outer shape of the pile body 2. Therefore, as shown in FIG. 6, the pile body 2 is arranged such that the outer peripheral surface thereof does not contact the inner peripheral surface of the cylindrical body 52 in a state where the cylindrical body 52 is externally fitted to the upper end portion of the pile main body 2. Can be taken. A flat plate 53 is fixed to the upper end of the cylindrical body 52 by welding. The flat plate 53 is a rectangular flat plate larger than the cross-sectional outer shape of the cylindrical body 52. The flat plate 53 is arranged so that the peripheral edge protrudes from the cylindrical body 52 as a flange, and is connected to the cylindrical body 52. Further, the upper surface of the flat plate 53 and the axial direction of the cylindrical body 52 are orthogonal to each other. The flat plate 53 is formed with a pair of holes penetrating in the thickness direction, and nuts 57 are fixed corresponding to the holes.

  The cylindrical body 52 is provided with a pair of support members 54 that protrude from the outer peripheral surface thereof and extend along the axial direction. Each upper end of the support member 54 is connected to the flat plate 53. The periphery of the flat plate 53 protruding from the cylindrical body 52 is supported from below by the support member 54.

  The pile head member 50 is carried by a disk 55 provided at the upper end portion of the pile body 2. As shown in FIG. 6, the disk 55 is a disk whose diameter is larger than the diameter of the cylindrical body 52, and a rectangular hole 56 is penetrated in the center in the thickness direction. The hole 56 is a square that is slightly larger than the cross-sectional outer shape of the pile body 2. That is, in the state where the pile body 2 is inserted through the hole 56, there is some play in the hole 56. As will be described later, this play is provided to such an extent that the upper surface of the disk 55 can be made horizontal in a state where the pile body 2 inclined in the axial direction is inserted through the hole 56. Then, although the axial direction of the pile body 2 and the axial direction of the cylinder body 52 do not match, as described above, the cross-sectional shape of the cylinder body 52 is sufficiently larger than the outer shape of the pile body 2, such an axial direction. In a state where the deviation is allowed, the cylindrical body 52 is fitted onto the upper end portion of the pile body 2. Such fitting between the cylindrical body 52 and the upper end portion of the pile body 2 is referred to as loose fitting in the present invention.

  The fixing metal 51 is attached to the bar 58 that is screwed to the nut 57 of the flat plate 53, the cylinder 59 that is externally fitted to the bar 58, the flat plate 60 that is connected to the upper end of the cylinder 59, and the bar 58. The nut 61 to be screwed is a main configuration. The bar 58 has a cylindrical shape with a male screw formed on the outer periphery, and the male screw is screwed into the nut 57. Thereby, the bar 58 is erected vertically with respect to the flat plate 53. Another nut 61 is screwed onto the bar 58, and the cylindrical body 59 is further fitted. The cylindrical body 59 is slidable in the length direction of the bar 58 while being fitted on the bar 58. When the lower end of the cylindrical body 59 comes into contact with the nut 61, the cylindrical body 59 is supported at a predetermined height with respect to the bar 58. A flat plate 60 is connected to the upper end of the cylindrical body 59. The upper surface of the flat plate 60 and the axial direction of the cylindrical body 59 are orthogonal to each other. Therefore, when the tubular body 59 is fitted on the bar 58, the flat plate 53 and the flat plate 60 of the pile head member 50 are arranged in parallel. And the height of the flat plate 60 is adjusted by changing the screwing position of the nut 61 with respect to the bar 58.

  Below, the construction method of this ready-made pile is explained in detail. This pre-made pile construction method is used for the foundation 8 that supports an already constructed building. The building is a house, for example, but the building is not particularly limited in the present invention. Further, the configuration of the foundation 8 is not particularly limited.

[First step]
In the first step, the work space 70 is formed by excavating the ground below the foundation 8 to be supported by the ready-made pile 1. The work space 70 is a space in which an operator works. The depth of the work space 70 is deeper than the length of one pile body 2 of the ready-made pile 1. That is, the working space 70 may be deep enough to stand the pile main body 2 in the vertical direction 75 and connect the jack 9 and the linear motion rotation conversion mechanism 10 described above. Moreover, it is not necessary to form the work space 70 all at once with respect to the whole foundation 8, and the work space 70 required in order to drive in one ready-made pile 1 should just be formed. Of course, it goes without saying that a work space 70 sufficient to drive a plurality of ready-made piles 1 may be formed.

[Second step]
In a 2nd process, the jack 9, the linear motion rotation conversion mechanism 10, and the ready-made pile 1 are sequentially connected to the lower surface of the foundation 8 in the vertical direction 75, and the ready-made pile 1 is rotationally penetrated into the ground. In this connection, first, the jack 9 is fixed to the lower surface of the foundation 8. As shown in FIG. 2, a flat plate-shaped fixing bracket 71 is fixed to the lower surface of the foundation 8 with a mortar 72, and the fixing bracket 71 and a flat plate 73 connected to the upper end of the jack 9 are connected. Although not shown in detail in FIG. 2, after-mounting anchor bolts such as hole-in anchors are installed on the lower surface of the foundation 8, and the fixing metal 71 is fixed using the anchor bolts. The mortar 72 is interposed between the lower surface of the mortar 8. The fixing bracket 71 is previously provided with a bolt capable of fastening the flat plate 73 fixed to the jack 9. Then, after the mortar 72 is solidified and fixed to the base 8 to the fixing metal 71, the flat plate 73 is fastened using the bolts and nuts of the fixing metal 71, and the jack 9 is suspended and fixed to the base 8.

  As shown in FIG. 2, the support member 13 is assembled in the work space 70. Specifically, the base plate 45 is laid on the ground in the work space 70, and the columns 41 and 42 are erected thereon. Then, the heights of the columns 41 and 42 are adjusted by the jack bases 46 and 47, and the upper ends of the columns 41 and 42 are brought into contact with the fixing bracket 71 to fix the columns 41 and 42. Two restraining rods 43 and 44 are connected to the support columns 41 and 42 in the horizontal direction at a predetermined interval. When assembling the restraining rods 43, 44, one of the two restraining rods 43, 44 is connected to the support posts 41, 42, and then the spiral member 11 is arranged at a predetermined height position. The remaining one is connected to the columns 41 and 42 so as to sandwich the spiral portion 20. Thus, the spiral member 11 is supported between the two restraining bars 43 and 44 at a predetermined height position.

  The upper end of the spiral member 11 is connected to the base of the jack 9 via the joint 12. The connecting plate 32 and the jack 9 of the spiral member 11 and the joint 12 may be connected using a known fixture such as a bolt. Further, the jack 9, the joint 12, and the spiral member 11 may be connected in advance by welding. On the other hand, the lower end of the spiral member 11 is connected to the ready-made pile 1. As described above, the connection is made by inserting the fitting portion 25 (see FIG. 3) provided at the lower end of the spiral member 11 into the upper end of the pile body 2 of the ready-made pile 1. This connection is made by fitting without using welding or the like. The tip of the ready-made pile 1 is slightly pierced into the ground through the hole of the base plate 45.

  The jack 9, the linear motion rotation conversion mechanism 10, and the ready-made pile 1 are sequentially connected to the lower surface of the foundation 8, and then the jack 9 is operated. As shown in FIG. 7A, when the jack 9 extends the rod by one stroke, the load on the foundation 8 and the building becomes a reaction force, and a pushing force is generated vertically downward from the jack 9. This pushing force is transmitted to the spiral member 11 through the joint 12. The spiral member 11 moves vertically downward by the pushing force. As described above, since the restraining rods 43 and 44 are engaged with the spiral grooves 21 and 22 of the spiral member 11, the spiral member 11 moves vertically downward along the spiral grooves 21 and 22. The direction 75 is rotated as an axial direction. The rotation and movement of the spiral member 11 are transmitted to the ready-made pile 1, and the ready-made pile 1 is driven into the ground while being rotated. Further, since the rotation of the spiral member 11 is not transmitted to the jack 9 by the joint 12, the jack 9 does not rotate and does not cause misalignment or the like. When the ready-made pile 1 is rotated, the peripheral surface of the ready-made pile 1 and the ground are cut off, and the ready-made pile 1 is easily driven. Further, the propulsive force in the vertical direction 75 is applied to the ready-made pile 1 by the rotation of the spiral blade 6 of the pile tip member 3 provided at the tip of the ready-made pile 1.

  After extending the jack 9 by one stroke and driving the ready-made pile 1 into the ground by a predetermined amount, the rod of the jack 9 is contracted. Along with this, the joint 12 and the spiral member 11 move vertically upward. The ready-made pile 1 is maintained in a state where the connecting portion 24 of the spiral member 11 is detached from the upper end of the pile body 2 and driven into the ground. When the spiral member 11 moves upward, it rotates along the spiral grooves 21 and 22 (rotation in the direction opposite to that during driving), and before the connecting portion 24 of the spiral member 11 is detached from the pile body 2. In addition, the rotation is slightly transmitted to the pile main body 2, but since the transmission of such rotation is slight, the ready-made pile 1 is not pulled out from the ground.

  After contracting the rod of the jack 9, a temporary pile 81 is added to the upper end of the pile body 2 as shown in FIG. Since the temporary pile 81 is to be removed later, it is sufficient that the push-in force and the rotation are transmitted to the pile main body 2. For example, a simple structure such as fitting of squares is adopted. The length L1 of the temporary pile 81 in the vertical direction 75 is substantially the same as the one stroke L0 of the jack 9. That is, when the jack 9 is driven one reciprocatingly, the ready-made pile 1 is driven into the ground for one stroke L0, so that the temporary pile 81 having a length L1 corresponding thereto is added to the pile body 2.

  1 stroke L0 of the jack 9 is short with respect to the length of the one pile main body 2 used by adding. If the length of one pile main body 2 is set to about one stroke L0 of the jack 9, the additional work will increase and the work will be complicated. On the other hand, the ready-made pile 1 cannot be driven into the ground more than the stroke L0 for one reciprocating drive of the jack 9. Therefore, when the jack 9 is reciprocated once, the temporary pile 81 having a length L1 corresponding to one stroke L0 of the jack 9 is temporarily joined to the upper end of the pile body 2.

  When the jack 9 is driven again, as shown in FIG. 8A, the load on the foundation 8 and the building becomes a reaction force as described above, and a pushing force is generated from the jack 9 in the vertically downward direction. . By this pushing force, the spiral member 11 moves vertically downward while rotating, and the ready-made pile 1 is driven into the ground while being rotated together with the temporary pile 81. Thereafter, when the rod of the jack 9 is contracted, the joint 12 and the spiral member 11 move vertically upward, and the ready-made pile 1 is driven into the ground with the connecting portion 24 of the spiral member 11 being detached from the upper end of the temporary pile 81. Maintained.

  After the rod of the jack 9 is contracted, the temporary pile 81 is removed from the upper end of the pile main body 2 and the temporary pile 82 is added to the upper end of the pile main body 2 instead. Since the temporary pile 82 is also removed later, a simple structure is adopted for this joining. The length L2 of the temporary pile 82 in the vertical direction 75 is almost twice the one stroke L0 of the jack 9. That is, when the jack 9 is driven twice, the ready-made pile 1 is driven into the ground for two strokes (L0 × 2), so that the temporary pile 82 having a length L2 corresponding to the pile is added to the pile body 2.

  When the jack 9 is driven again, as shown in FIG. 9A, the load on the foundation 8 and the building becomes a reaction force as described above, and a pushing force is generated vertically downward from the jack 9. . With this pushing force, the spiral member 11 moves vertically downward while rotating, and the ready-made pile 1 is driven into the ground while being rotated together with the temporary pile 82. Thereafter, when the rod of the jack 9 is contracted, the joint 12 and the spiral member 11 move vertically upward, and the ready-made pile 1 is driven into the ground with the connecting portion 24 of the spiral member 11 being detached from the upper end of the temporary pile 82. Maintained.

  After contracting the rod of the jack 9, the temporary pile 82 is removed from the upper end of the pile main body 2 as shown in FIG. 9B, and the temporary pile 83 is added to the upper end of the pile main body 2 instead. Since the temporary pile 83 is also removed later, a simple structure is adopted for this joining. The length L3 of the temporary pile 83 in the vertical direction 75 is approximately three times the one stroke L0 of the jack 9. That is, when the jack 9 is driven three times, the ready-made pile 1 is driven into the ground for three strokes (L0 × 3), so that the temporary pile 83 having a length L3 corresponding to the pile is added to the pile body 2.

  When the jack 9 is driven again, the load on the foundation 8 and the building becomes a reaction force as described above, and a pushing force is generated vertically downward from the jack 9. By this pushing force, the spiral member 11 moves vertically downward while rotating, and the ready-made pile 1 is driven into the ground while being rotated together with the temporary pile 83. Thereafter, when the rod of the jack 9 is contracted, the joint 12 and the spiral member 11 move vertically upward, and the ready-made pile 1 is driven into the ground with the connecting portion 24 of the spiral member 11 being detached from the upper end of the temporary pile 83. Maintained.

  After contracting the rod of the jack 9, the temporary pile 83 is removed from the upper end of the pile body 2, and is added to the upper end of another pile body 2 instead. This joining is performed firmly using welding or the like. In the present embodiment, the length of one pile body 2 is approximately four times the one stroke L0 of the jack 9. That is, when the jack 9 is driven to reciprocate four times, the ready-made pile 1 is driven into the ground for 4 strokes (L0 × 4), so between the upper end of the driven ready-made pile 1 and the jack linear motion rotation conversion mechanism 10, Since the space of the length of the one pile main body 2 arises, it replaces with the temporary pile 83 and the new pile main body 2 is added. This joining is performed firmly using welding or the like. Moreover, each temporary pile 81-83 is used again until the next new pile main body 2 is added.

  In addition, in this embodiment, although the length of one pile main body 2 was made into 4 times of 1 stroke L0 of the jack 9, the relationship between the length of the pile main body 2 and the stroke of the jack 9 is in this embodiment. Needless to say, for example, the length of one pile body 2 may be approximately three times or five times the one stroke L0 of the jack 9.

  By repeating this, the ready-made pile 1 is driven into the ground while adding a plurality of pile bodies 2. Thereby, the ready-made pile 1 can be driven to a desired support ground using the pile main body 2 having a length that allows the work to be brought into the work space 70.

  In the second step, the third step is performed after the ready-made pile 1 is driven into the ground to a predetermined depth. In a 3rd process, the jack 9 and the linear motion rotation conversion mechanism 10 are removed, and the upper end of the ready-made pile 1 and the foundation 8 are connected. This connection is performed using the pile head member 50 and the fixture 51 as described above. Specifically, the jack 9 and the linear motion rotation conversion mechanism 10 are removed, and a space is provided between the lower surface of the foundation 8 and the upper end of the ready-made pile 1. Then, as shown in FIG. 5, the disk 55 and the disk 62 are externally fitted to the pile body 2 of the ready-made pile 1. Since the disk 62 has the same configuration as the disk 55, a detailed description thereof is omitted here. The disk 62 is welded and fixed to the outer peripheral surface of the pile body 2 so as to be laid on the ground. The reaction force against the pushing force to the pile body 2 is increased by the disk 62.

  The disk 55 is welded and fixed to the outer peripheral surface of the pile body 2 such that the upper surface thereof is horizontal. Moreover, the distance from the disk 55 to the upper end of the pile main body 2 is made shorter than the length of the cylindrical body 52 of the pile head member 50. Here, as shown in FIG. 10, the axial direction 74 of the ready-made pile 1 driven into the ground may not necessarily coincide with the vertical direction 75. On the other hand, the lower surface of the foundation 8 is horizontal. If the foundation 8 or the building is inclined due to uneven settlement, the inclination of the foundation 8 is restored at the time of the main construction, so that the lower surface of the foundation 8 becomes horizontal. In such a case, a gap or the like is likely to be generated in the connection portion between the ready-made pile 1 and the foundation 8, and as a result, the connection portion may be broken. On the other hand, by arranging the disk 55 horizontally and supporting the pile head member 50 on the disk 55, the flat plate 60 of the pile head member 50 and the lower surface of the foundation 8 are made parallel as will be described later. It is possible to secure a connection without a gap.

  As shown in FIG. 6, the cylindrical body 52 of the pile head member 50 is sufficiently large with respect to the outer shape of the pile main body 2, so that the pile main body 2 is inserted into the cylindrical body 52 obliquely as shown in FIG. 10. can do. That is, the pile head member 50 is positioned so that the upper surface of the flat plate 60 is horizontal by allowing the cylindrical body 52 to be loosely fitted to the upper end of the pile body 2 and allowing the inclination of the pile body 2 in the axial direction. Can do. Then, the fixing bracket 51 is attached to the pile head member 50. In this mounted state, the cylinder 59 is positioned relatively below the bar 58, and the flat plate 60 fixed to the upper end of the cylinder 59 is also positioned relatively below. Subsequently, the jack 14 is placed on the flat plate 53 of the pile head member 50. The jack 14 is the same as the jack 9 described above.

  When the jack 14 is driven to extend the rod, the foundation 8 and the building are lifted together with the cylindrical body 52 and the flat plate 53 of the fixing bracket 51. The tip of the ready-made pile 1 has reached the support ground, and further, by providing the disk 62, the ready-made pile 1 can support the load of the foundation 8 and the building. After lifting the unevenly settled foundation 8 and the building to make it horizontal, the position of the nut 61 screwed into the bar 58 of the fixing bracket 51 is adjusted, and the cylindrical body 52 and the flat plate 53 are fixed to a predetermined height. . Thereby, since the flat plate 53 of the pile head member 50, the flat plate 60 of the fixing bracket 51, and the lower surface of the foundation 8 are all horizontal and parallel to each other, the ready-made pile 1 and the foundation 8 are securely connected without a gap. be able to. Moreover, a non-shrink mortar is filled in the gap between the cylinder body 52 of the pile head member 50 and the upper end of the pile body 2 to fill the gap.

  In the fourth step, the work space 70 is refilled. At the time of this backfilling, concrete is cast around the pile head member 50 to connect the ready-made pile 1 and the foundation 8 more firmly.

[Operational effects of this embodiment]
According to the present embodiment, the jack 9, the linear motion rotation conversion mechanism 10, and the ready-made pile 1 are connected to the bottom surface of the foundation 8 in the vertical direction 75, and the jack 9 is driven to load the foundation 8 and the building. Is transmitted to the ready-made pile 1 as rotation and pushing force by the linear motion rotation converting mechanism 10, and it becomes easy to drive the ready-made pile 1 into the ground. As a result, the ready-made pile 1 can be driven to the support ground by effectively utilizing the limited load, and a long-term reliable repair method can be realized against uneven settlement.

  Moreover, the spiral member 11, the joint 12, and the support member 13 are used as the linear motion rotation conversion mechanism 10, and the spiral member 11 moves downward while rotating with the extension of the rod of the jack 9. Since it is rotationally penetrated into the ground, the linear motion rotation converting mechanism 10 is realized in the work space 70 in a simple and space-saving manner.

  Further, in the second step, the pile body 2 having a predetermined length is driven into the ground while being added, so that the ready-made pile can be driven to the desired support ground without making the work space 70 excessive.

  In the second step, every time the jack 9 is reciprocated, temporary piles 81 to 83 having a length corresponding to (the number of reciprocating times of the jack 9) × (stroke L0 of the jack 9) are sequentially used. Therefore, the man-hour of the extension work of the pile main body 2 whose length is longer than the stroke L0 of the jack 9 can be reduced.

  Further, in the third step, since the ready-made pile 1 is connected to the foundation 8 using the pile head member 50 and the fixing bracket 51, the ready-made pile 1 whose axial direction 74 does not coincide with the vertical direction 75 can be easily and reliably used as the foundation 8. Can be linked.

[Modification]
In addition, in the said embodiment, in the linear motion rotation conversion mechanism 10, when the spiral member 11 engages with the restraining rods 43 and 44, the pushing force of the jack 9 is transmitted to the ready-made pile 1 as rotation and pushing force. However, instead of the restraining rods 43 and 44, a restraining member 48 shown in FIG. 11 may be used. The restraining member 48 has a cubic shape wider than the spiral member 11, and a through groove 49 is formed in the thickness direction thereof. The through groove 49 has an elongated shape corresponding to the thickness and width of the spiral portion 20 of the spiral member 11, and is twisted in a spiral shape in the thickness direction of the restraining member 48. Although not shown in detail in FIG. 11, the spiral shape registration of the through groove 49 matches the spiral shape of the spiral portion 20. Therefore, when the restraining member 48 is fixed as a part of the support member 13 and the spiral member 11 is advanced and retracted in the through groove 49, the spiral member 11 is guided by the through groove 49 and rotates. Even when such a restraining member 48 is used, the same effect as described above is exhibited.

FIG. 1 is a perspective view showing a ready-made pile 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a construction method of the ready-made pile 1 in the work space 70. FIG. 3 is a perspective view showing the configuration of the spiral member 11. FIG. 4 is a longitudinal sectional view showing the internal configuration of the joint 12. FIG. 5 is a schematic view showing a state in which the pile head member 50 and the fixture 51 are assembled. 6 is a cross-sectional view taken along line VI-VI in FIG. Drawing 7 is a mimetic diagram for explaining each process in a construction method of a ready-made pile. Drawing 8 is a mimetic diagram for explaining each process in a construction method of a ready-made pile. Drawing 9 is a mimetic diagram for explaining each process in a construction method of a ready-made pile. FIG. 10 is a schematic diagram showing a state in which the axial direction 74 of the ready-made pile 1 is inclined with respect to the vertical direction 75. FIG. 11 is a perspective view showing a restraining member 48 according to a modification of the present embodiment.

Explanation of symbols

1 ... Ready-made pile 2 ... Pile body (Pre-made pile)
8 ... foundation 9 ... jack 10 ... linear motion rotation conversion mechanism 11 ... spiral member 12 ... joint 13 ... support members 21, 22 ... spiral grooves 23, 24 ... Connecting part 32 ... connecting plate (first connecting part)
33 ... Connecting plate (second connecting part)
50 ... Pile head member 51 ... Fixing bracket 52 ... Tube 53 ... Flat plate 70 ... Work spaces 81-83 ... Temporary pile

Claims (6)

A first step of excavating the ground below the foundation to form a working space;
In the work space, a second step of driving the jack into the ground while rotating the ready-made pile by connecting the jack, the linear motion rotation conversion mechanism, and the ready-made pile in the vertical direction in the work space, and driving the jack.
A third step of detaching the jack and the linear motion rotation conversion mechanism and connecting the upper end of the ready-made pile driven into the ground and the foundation;
A method for constructing a ready-made pile including the fourth step of refilling the work space. As the linear motion rotation conversion mechanism,
A spiral member that is formed on the outer periphery of the spiral groove that proceeds in the extending direction, and has a connecting portion with the ready-made pile at one end in the extending direction;
A joint in which a first connecting portion connected to the jack and a second connecting portion to which the spiral member is connected are rotatable with respect to a connecting direction;
A support member that engages with the spiral groove with the extending direction as a vertical direction to support the spiral member at a predetermined position, and that can advance and retract in the vertical direction while rotating the spiral member along the spiral groove; The construction method of the ready-made pile according to claim 1 which uses the above.   In the said 2nd process, the construction method of the ready-made pile of Claim 1 or 2 driven into the ground, adding the ready-made pile of predetermined length. In the second step,
Each time the jack is reciprocated by one stroke, the temporary pile is replaced with a temporary pile having a length corresponding to (the number of times the jack is reciprocated) × (jack stroke). Temporarily connect and drive the jack,
The construction method of the ready-made pile of Claim 3 which replaces with the said temporary pile, and adds a ready-made pile after driving the said jack several times according to the length of the ready-made pile to add. In the third step,
A pile head member having a cylindrical body loosely fitted to the upper end of the ready-made pile and a flat plate connected to the upper end of the cylindrical body is connected to the upper end of the ready-made pile with the flat plate parallel to the lower surface of the foundation. And the construction method of the ready-made pile in any one of Claim 1 to 4 which connects the said flat plate and the lower surface of the said foundation using a fixing metal fitting.   A foundation support structure in which a foundation of a building is supported on a ready-made pile placed in the ground by the method according to any one of claims 1 to 5.

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