JP6437765B2 - Floating prevention member, vertical shaft provided with floating prevention member, and installation method of floating prevention member in shaft - Google Patents

Description

  The present invention relates to a floating prevention member that prevents a shaft built up by being submerged in soil, a shaft provided with the floating prevention member, and a method for installing the floating prevention member in the shaft.

  Conventionally, the caisson method is known as one of the methods for constructing a shaft in the soil. As one of the caisson methods, there is a segment press-fitting method in which a plurality of steel segments are connected in a ring shape to assemble a frame, and a caisson (vertical shaft) is constructed by press-fitting into the ground from the ground surface of the installation site. is there. By the way, the caisson constructed by the segment press-fitting method is lighter than the caisson constructed by concrete, so it is easily affected by buoyancy due to groundwater, and the caisson can not resist the buoyancy due to its own weight. It has the disadvantage of floating up.

  As a method of obtaining the reaction force against the buoyancy, there is a caisson provided with a plurality of anti-floating members that protrude from the housing toward the ground outside the caisson (see Patent Document 1).

JP 2014-125823 A

  The caisson includes a support member fixed to a communication portion provided on the side wall of the caisson and connected to a communication portion, and a load transmission member protruding into the soil, and the load transmission member is provided in a hole provided in the support member. The base end side joint portion is supported, and the distal end side of the load transmitting member protrudes into the soil outside the side wall. And the force which the said load transmission member received from the said natural ground is transmitted to the said caisson via the said support member. As a result, the force acts on the caisson as a reaction force against the buoyancy, and the caisson is held at a predetermined depth in the soil.

  Incidentally, as shown in FIG. 14, in the floating prevention member 100, the load transmission member 102 is supported by a hole 108 provided in a support member 106 fixed to a side wall 104 of the caisson (hereinafter referred to as a vertical shaft). Further, the proximal end 102a of the load transmission member 102 is restricted from displacement in the shaft inner direction in the axial direction of the load transmission member 102 by a lid 110 fixed to the side wall 104 of the shaft.

  When the buoyancy F1 acts on the shaft laid in the soil, a force F2 (see FIG. 14) acts on the load transmitting member 102 from the ground as a reaction force of the buoyancy F1. A rotational moment M1 is applied to the load transmitting member 102 to rotate the load transmitting member 102 counterclockwise in FIG. 14 by the buoyancy F1 and the force F2. Here, in a state where the load transmitting member 102 protrudes into the soil, earth and sand or the like enter between the proximal end 102a of the load transmitting member 102 and the lid 110, and the load transmitting member 102, the lid 110, There may be a gap 112 between the two.

  For this reason, since the load transmission member 102 and the lid 110 are not in contact with each other, the force F2 is not transmitted from the load transmission member 102 to the lid 110. As a result, the force F2 acting on the load transmission member 102 acts upward on the support member 106 that supports the end portion 102a on the proximal end side of the load transmission member 102 by the rotational moment M1.

  Here, when the side wall 104 of the shaft is thin, the length of the support member 106 in the axial direction is shortened, so that the contact area between the load transmission member 102 and the support member 106 is reduced, and the force F2 is applied to the side wall of the shaft. Acts locally at 104. As a result, the communication portion that fixes the support member 106 in the side wall 104 of the shaft may be damaged without being able to withstand the force F2. As a result, the reaction force from the floating prevention member 100 cannot be transmitted to the shaft, and the shaft may not be held at a predetermined position in the soil.

  The present invention has been made in view of the above problems, and an object of the present invention is to reliably transmit a force from a natural ground acting on a floating prevention member to a shaft and to improve the proof stress of the floating prevention member.

  In order to achieve the above object, the shaft floating prevention member according to the first aspect of the present invention is a floating prevention member for preventing the shaft from being lifted by submerging the skeleton in the soil, and A cylindrical portion protruding into the soil, and an end plate having a flange portion that is provided integrally with an end portion on the shaft side of the cylindrical portion and that is fixed to an inner wall of the shaft. To do.

  According to this aspect, the cylindrical portion and the flange portion are integrally provided, and the flange portion is fixed to the inner wall of the shaft, whereby the force from the natural ground is more reliably transmitted to the shaft. It is possible to reliably prevent the shaft from being lifted. In addition, by fixing a flange portion having a diameter larger than that of the tubular portion in the radial direction of the tubular portion to the inner wall of the shaft, the flange portion and the contact area between the tubular portion and the shaft The contact area with the inner wall of the shaft can be increased. As a result, since the force from the natural ground is distributed and transmitted to the inner wall of the shaft through the flange portion, the stress per unit area at the contact portion between the flange portion and the inner wall can be reduced. As a result, the float prevention member, for example, allows a force larger than the force from the ground that acts on the tubular portion that is allowed when only the end portion of the tubular portion is supported by the shaft. Can do. Accordingly, it is possible to improve the proof stress of the floating prevention member.

  The shaft floating prevention member according to the second aspect of the present invention is the shaft according to the first aspect, wherein a part of the end plate enters the cylindrical portion at an end of the cylindrical portion on the shaft side. Features.

  According to this aspect, since a part of the end plate enters the cylindrical part at the end of the cylindrical part on the shaft side, for example, the part that enters the cylindrical part is the cylindrical part. It can be set as the state which contacted the inner peripheral surface in the edge part of the said shaft side. Thereby, the said cylindrical part and the said end plate can be integrated more reliably, and transmission of the force from the said cylindrical part to the said end plate can be ensured.

  According to a third aspect of the present invention, the shaft anti-floating member according to the first aspect or the second aspect is characterized in that the end plate is grouted in the cylindrical portion with the cylindrical portion protruding into the soil. It is provided with a valve capable of injecting material.

  According to this aspect, the strength of the cylindrical portion can be improved by storing the excavated soil in the cylindrical portion and pouring and solidifying the grout material.

  The shaft lifting prevention member according to the fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, a drilling member (tip) is provided at a tip of the cylindrical portion. To do.

  According to this aspect, by providing the excavation member in the cylindrical portion, the installation process of the floating prevention member can be reduced. The excavation member includes a bit, a chip, and the like.

  According to a fifth aspect of the fifth aspect of the present invention, in the shaft according to the fourth aspect, the excavation member is formed such that a diameter of a cutting edge circle formed by the excavation member is larger than an outer diameter of the cylindrical portion. It is characterized by.

  According to this aspect, since the diameter of the cutting edge circle formed by the excavation member is larger than the outer diameter of the cylindrical portion, the frictional force between the outer peripheral surface of the cylindrical portion and the ground around the outer peripheral surface is reduced. It is possible to reduce the force necessary for the excavation of the cylindrical portion. Therefore, installation of the floating prevention member can be made easier.

  A vertical shaft provided with the anti-floating member of the sixth aspect of the present invention is a vertical shaft provided with the anti-floating member according to any one of the first to fifth aspects, which is constructed by sinking a frame in the soil. A plurality of anti-floating member mounting portions provided at intervals in the axial direction and the circumferential direction of the shaft, wherein the anti-floating member mounting portion includes a thin plate constituting a part of the outer wall of the shaft, A sealing member disposed closer to the inner wall and facing the thin plate, wherein the sealing member penetrates the thin plate and projects the tubular portion of the anti-floating member into the soil. An end portion of the tubular portion on the end plate side is surrounded and held, and the end plate is fixed to an inner wall of the shaft.

  According to this aspect, the same effect as that obtained in any one of the first to fifth aspects can be obtained.

  The shaft provided with the anti-floating member according to the seventh aspect of the present invention is the shaft according to the sixth aspect, wherein the end of the end plate opposite to the side where the tubular portion is provided is flush with the inner wall of the shaft. It is characterized by being.

  According to this aspect, since the end of the end plate opposite to the side where the cylindrical portion is provided is flush with the inner wall of the shaft, the anti-floating member is inward from the inner wall of the shaft. It has not jumped out. Therefore, it is possible to effectively use the internal space in the shaft and prevent the work in the shaft from being hindered.

  In the sixth or seventh aspect, the vertical shaft including the floating prevention member according to the eighth aspect of the present invention is formed with a space surrounding the cylindrical portion between the thin plate and the sealing member, Is characterized by being filled with grout material.

  According to this aspect, by filling and solidifying the grout material in the space formed so as to surround the outer peripheral surface of the cylindrical portion, the cylindrical portion can be held from the periphery of the cylindrical portion, The yield strength of the anti-floating member can be improved.

  The shaft having the float prevention member according to the ninth aspect of the present invention is characterized in that, in any one of the sixth to eighth aspects, the sealing member is an oil seal.

  The method for installing a floating prevention member according to the tenth aspect of the present invention is a method for installing a floating prevention member in a shaft constructed by submerging a skeleton in the soil, and is spaced in the axial direction and the circumferential direction of the shaft. In the plurality of anti-floating member mounting portions provided at the top, the tubular portion of the anti-floating member having a drilling member at the tip is passed through the sealing member provided on the anti-floating member mounting portion, and the tubular portion is rotated. And a step of excavating a part of the outer wall of the shaft in the floating prevention member attaching portion, and a part of the outer wall of the shaft that passes through the outer wall of the shaft and digs into the soil outside the shaft. Projecting from the outer wall of the shaft and fixing the end plate of the float prevention member to the inner wall of the shaft.

  According to an eleventh aspect of the present invention, in the tenth aspect, the method for installing a float prevention member includes a step of injecting a grout material into the cylindrical portion via a valve provided on the end plate, and the float prevention member. And a step of injecting the grout material into a space formed between the thin plate and the sealing member in the attachment portion.

Sectional drawing which shows the outline | summary of a shaft provided with the floating prevention member which concerns on 1st Example of this invention. Sectional drawing in the axial direction of a shaft provided with the floating prevention member which concerns on a 1st Example. The perspective view of the floating prevention member which concerns on a 1st Example. Sectional drawing of the floating prevention member which concerns on a 1st Example. Sectional drawing of the attaching part of the floating prevention member in the shaft which concerns on a 1st Example. Sectional drawing which shows the state which attached the float prevention member which concerns on a 1st Example to a shaft. (A) is a fragmentary sectional view which shows the 1st state of the installation process of the float prevention member which concerns on 1st Example, (B) is a fragmentary sectional view which shows the 2nd state of the installation process of a float prevention member . (A) is a fragmentary sectional view which shows the 3rd state of the installation process of a float prevention member, (B) is a fragmentary sectional view which shows the 4th state of the installation process of a float prevention member. (A) is a fragmentary sectional view which shows the 5th state of the installation process of a float prevention member, (B) is a fragmentary sectional view which shows the 6th state of the installation process of a float prevention member. Sectional drawing which shows the state which attached the float prevention member which concerns on a 2nd Example to the shaft. Sectional drawing which shows the state which attached the float prevention member which concerns on a 3rd Example to the shaft. The fragmentary sectional view which shows the 1st state of the installation process of the floating prevention member in the shaft which concerns on the example of a change of a 1st Example. The fragmentary sectional view which shows the 2nd state of the installation process of the floating prevention member in the shaft which concerns on the example of a change of a 1st Example. The fragmentary sectional view which shows the installation state of the floating prevention member in a prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, about the same structure in each Example, the same code | symbol is attached | subjected and it demonstrates only in the first Example, The description of the structure is abbreviate | omitted in a subsequent Example.

■■■ First Example ■■■■
<<< About the structure of the shaft >>>
With reference to FIG.1 and FIG.2, the shaft 12 provided with two or more float prevention members 10 which concern on a 1st Example is demonstrated. The shaft 12 is a shaft main body 16 that is press-fitted and submerged from the ground surface 14 into the ground, and a plurality of floating prevention members 10 that protrude from the side wall 18 of the shaft main body 16 toward the ground outside the shaft main body 16. And a bottom plate 20 provided at the bottom of the shaft main body 16.

  As shown in FIG. 1, the shaft main body 16 is configured by stacking a plurality of frames 22 in the axial direction of the shaft main body 16. In the present embodiment, the casing 22 is made of steel, RC, or a cylindrical member having a composite structure, for example, a thin circular tube. In addition, the thickness of the cylindrical member made of steel in the present embodiment is configured to be smaller than the thickness in the radial direction of the caisson formed by connecting a plurality of segments in a ring shape.

  The shaft 12 is driven with a bottom slab 20 (underwater concrete) (see FIG. 1) after completing the installation of the frame 22, and after pumping up the water in the shaft main body 16, the shaft main body 16 and the outer ground The mortar (not shown) is grouting from a grout hole (not shown) provided in the casing 22 during this period to fill the gap between the casing 22 and the ground, thereby bringing the casing 22 into close contact with the ground and preventing ground subsidence. it can.

  Further, as shown in FIGS. 1 and 2, after placing the bottom plate 20 on the bottom of the shaft main body 16, a plurality of floats are formed in the shaft main body 16 from the side wall 18 of the shaft main body 16 toward the soil outside the side wall 18. The prevention member 10 is protruded. The floating prevention members 10 are provided at intervals in the circumferential direction of the shaft main body 16. In the present embodiment, as shown in FIG. 1, the floating prevention members 10 are provided in two rows at intervals along the axial direction of the shaft main body 16.

  In addition, a resistance force F4 is applied to the floating prevention member 10 from the natural ground as a reaction force against the buoyancy F3 (see FIG. 1) due to the groundwater that acts on the shaft main body 16. When the sum of the resistance forces F4 acting on all the float prevention members 10 is larger than the buoyancy F3 acting on the shaft main body 16, the shaft main body 16 is prevented from being lifted by the buoyancy F3, and the shaft main body 16 is set in the ground. Can be held at a depth of. In the present embodiment, the predetermined depth is, for example, a depth of 20 m or more.

<<< Regarding the structure of the anti-floating member >>>
Next, the configuration of the floating preventing member 10 according to the first embodiment will be described with reference to FIGS. 3 and 4. The float prevention member 10 includes a cylindrical portion 24 and an end plate 26. The cylindrical portion 24 is formed in a cylindrical shape in this embodiment. A drilling member 28 is attached to the end 24 a on the distal end side of the cylindrical portion 24. By providing the excavation member 28 in the cylindrical part 24, the installation process of the floating prevention member 10 can be reduced. The excavation member 28 includes a bit, a chip, and the like.

  The excavation member 28 is provided at the end portion 24a on the distal end side so as to protrude outward in the radial direction from the diameter dimension of the end portion 24a on the distal end side. That is, the cutting edge diameter on the outer peripheral side of the excavating member 28 is set larger than the diameter dimension of the end portion 24a on the distal end side. For this reason, the frictional force between the outer peripheral surface of the end portion 24a on the distal end side and the ground around the outer peripheral surface can be reduced, and the force required for the excavation of the cylindrical portion 24 can be reduced. Therefore, it is possible to more easily install the anti-floating member 10 on the natural ground.

  The cutting edge diameter on the inner peripheral side of the excavation member 28 is set smaller than the inner diameter dimension of the end portion 24a on the distal end side. For this reason, when the thin plate 38 of the mounting portion 36 described later is cut and cut, the diameter of the cut thin plate 38 a can be made smaller than the inner diameter of the cylindrical portion 24.

  As shown in FIG. 4, the end plate 26 includes a flange portion 30 having a diameter larger than the diameter of the tubular portion 24 in the circumferential direction of the tubular portion 24, and a proximal end side (a shaft side) of the tubular portion 24. The end portion 24 b includes an insertion portion 32 that enters the cylindrical portion 24. That is, the end plate 26 is formed as a disk-shaped member in this embodiment.

  In the present embodiment, the flange portion 30 of the end plate 26 is welded to the end portion 24 b on the machine end side of the cylindrical portion 24. That is, the end plate 26 is provided integrally with the cylindrical portion 24. In FIG. 4, a black triangle on the end 24 b side on the proximal end side of the cylindrical portion 24 indicates a welded portion between the cylindrical portion 24 and the end plate 26.

  Further, the insertion portion 32 is set such that the thickness dimension in the axial direction of the end plate 26 is larger than the thickness dimension of the flange portion 30. That is, as shown in FIG. 4, the insertion portion 32 is configured to protrude toward the end portion 24 b on the proximal end side of the tubular portion 24 with respect to the flange portion 30.

  In the present embodiment, the insertion portion 32 enters the cylindrical portion 24 at the proximal end 24 b of the cylindrical portion 24. That is, the outer peripheral surface of the insertion portion 32 is in contact with the inner peripheral surface of the end portion 24 b on the proximal end side of the tubular portion 24. With this configuration, displacement of the cylindrical portion 24 in the direction intersecting the axial direction with respect to the end plate 26 is restricted. That is, in addition to welding the cylindrical portion 24 and the end plate 26 in the anti-floating member 10, the configuration is such that the inner peripheral surface of the cylindrical portion 24 and the outer peripheral surface of the insertion portion 32 are in contact with each other. The part 24 and the end plate 26 can be integrated more reliably.

  Further, the end plate 26 includes a check valve 34. In the present embodiment, the check valve 34 is provided at the circumferential center portion of the end plate 26, that is, at the insertion portion 32. In this embodiment, the check valve 34 is configured to be able to inject liquid into the cylindrical portion 24. In this embodiment, the liquid refers to water or grout material as an example.

<<< About the mounting part of the floating prevention member in the shaft >>>
Next, the configuration of the attachment portion 36 of the floating prevention member 10 in the shaft main body 16 will be described with reference to FIGS. 5 and 6. In the present embodiment, the side wall 18 of the shaft main body 16 is provided with an attachment portion 36 for the float prevention member 10.

  The attachment portion 36 includes a thin plate 38 that forms the outside, that is, a part of the outer wall 18 a in the side wall 18 of the shaft main body 16, and a sealing member 40. In this embodiment, the thin plate 38 is made of a steel plate having a thickness of about several mm. The sealing member 40 is configured as an oil seal in this embodiment. Here, the inner diameter of the sealing member 40, that is, the oil seal is set to a dimension capable of holding the cylindrical portion 24 of the floating prevention member 10. That is, the sealing member 40 prevents the communication between the outer wall 18a side and the inner wall 18b side in the shaft main body 16 when the cylindrical portion 24 is rotated in a state where the cylindrical portion 24 is received, and the shaft main body from the natural ground side. Intrusion of earth and sand and groundwater into 16 can be prevented.

  Further, in the attachment portion 36, the sealing member 40 is provided at a distance from the thin plate 38 in the radial direction of the shaft main body 16, and faces the thin plate 38. Further, a space 42 is formed between the thin plate 38 and the sealing member 40 in the radial direction of the shaft main body 16 in the attachment portion 36.

  The space 42 is configured to be a cylindrical space whose axial direction is the radial direction of the shaft main body 16 when the cylindrical portion 24 of the anti-floating member 10 is passed through the sealing member 40. The space 42 is provided with a drainage channel 44 communicating with the inner side of the side wall 18 of the shaft main body 16, that is, the inner wall 18 b side. A water stop valve 46 is attached to the end of the drainage channel 44 on the inner wall 18b side.

  FIG. 6 shows a state where the float prevention member 10 is attached to the attachment portion 36. The mounting process of the floating prevention member 10 will be described in detail later. In the state shown in FIG. 6, the tubular portion 24 of the floating prevention member 10 protrudes from a thin plate 38 constituting a part of the outer wall 18 a of the shaft main body 16 to a natural mountain outside the outer wall 18 a. Here, the anti-floating member 10 rotates the anti-floating member 10 while being held by the sealing member 40, and cuts and cuts the thin plate 38 by the excavating member 28 provided at the tip of the cylindrical portion 24. Can do. And the float prevention member 10 can be made into the state which protruded the cylindrical part 24 from the outer wall 18a by digging toward the natural ground, rotating as it is.

  In the present embodiment, the flange portion 30 and the inner wall 18b are welded in a state in which the flange portion 30 of the end plate 26 of the floating prevention member 10 is in contact with the inner wall 18b of the shaft main body 16. Thereby, the end plate 26 of the floating prevention member 10 is fixed to the inner wall 18b. In FIG. 6, a black triangle between the end plate 26 and the inner wall 18b indicates a welded portion between the end plate 26 and the inner wall 18b.

  Here, in the case where the end portion 24b on the base end side of the tubular portion 24 is supported by the shaft main body 16 in the floating prevention member 10, when the shaft main body 16 is a steel thin circular tube as in this embodiment, The contact area between the shaft main body 16 and the end portion 24b on the proximal end side of the tubular portion 24 is reduced. Thereby, since the force from the natural ground which acts on the cylindrical part 24 concentrates on the contact part with the cylindrical part 24 in the shaft main body 16, there exists a possibility that the cylindrical part 24 cannot be hold | maintained.

  In this embodiment, the cylindrical portion 24 and the end plate 26 are integrally formed by welding in the floating preventing member 10, and the flange portion 30 of the end plate 26 of the floating preventing member 10 is fixed to the inner wall 18 b of the shaft main body 16. ing. Therefore, when buoyancy F3 (see FIG. 1) due to groundwater acts on the shaft main body 16, a resistance force F4 that acts on the tubular portion 24 from the ground is generated as a reaction force against the buoyancy F3. The resistance force F4 and the buoyancy F3 cause a rotation moment M2 in the anti-floating member 10. As a result, the resistance force F4 is converted into a force F5 that presses the inner wall 18b via the flange portion 30 by the rotational moment M2. Thereby, the resistance force F4 from the natural ground outside the outer wall 18a can be more reliably transmitted to the shaft main body 16. As a result, the float prevention member 10 can reliably prevent the shaft main body 16 from being lifted.

  Further, by fixing the flange portion 30 having a diameter larger than that of the tubular portion 24 in the radial direction of the tubular portion 24 to the inner wall 18b of the shaft main body 16, the proximal end side end portion 24b of the tubular portion 24 and The contact area between the flange portion 30 and the inner wall 18b of the shaft main body 16 can be increased with respect to the contact area with the shaft main body 16. As a result, since the force F4 from the natural ground outside the outer wall 18a is distributed and transmitted to the inner wall 18b of the shaft main body 16 via the flange portion 30, the stress per unit area at the contact portion between the flange portion 30 and the inner wall 18b. Can be reduced. As a result, the float prevention member 10 receives the force acting on the tubular portion 24 from the natural ground outside the outer wall 18a that is allowed when only the proximal end portion 24b of the tubular portion 24 is supported by the shaft main body 16. Can also tolerate large forces. Therefore, the proof stress of the floating preventing member 10 can be improved.

  In this embodiment, the end plate 26 is provided with a check valve 34 so that the grout material 48 can be injected into the cylindrical portion 24. And in the state which the floating prevention member 10 protruded from the side wall 18 of the shaft main body 16, the grout material 48 is inject | poured and solidified in the cylindrical part 24 which protruded from the check valve 34 to the natural ground. As a result, the strength of the tubular portion 24 can be improved by accommodating the excavated soil in the tubular portion 24 and pouring and solidifying the grout material 48.

  Further, a grout material 48 is injected into the space 42 via a drainage channel 44 and a water stop valve 46 and is solidified. As a result, the float prevention member 10 not only holds the end plate 26 by the inner wall 18b of the shaft main body 16, but also forms a cylindrical end portion 24b of the cylindrical portion 24 at the attachment portion 36 of the shaft main body 16. It can be held from around the portion 24. As a result, the float prevention member 10 is held on the side wall 18 of the shaft main body 16 at two locations, that is, the end plate 26 and the end portion 24b on the proximal end side of the cylindrical portion 24, and therefore the ground outside the outer wall 18a The proof strength of the floating preventing member 10 against the force F4 acting on the cylindrical portion 24 from the mountain can be improved.

<<< Regarding the installation process of the anti-floating member in the main shaft >>>
Then, with reference to FIG. 6 thru | or FIG. 9 (B), the installation process in the shaft main body 16 of the floating prevention member 10 is demonstrated. First, referring to FIG. 7A, the boring machine 50 is installed on a work table (not shown) installed in the shaft main body 16. The float prevention member 10 is attached to the main shaft 52 of the boring machine 50. Specifically, the end plate 26 of the floating prevention member 10 is detachably attached to the main shaft 52 of the boring machine 50 by a fastening member 54 such as a screw or a bolt. In this embodiment, the anti-floating member 10 and the boring machine 50 are installed at a position where the axis of the anti-floating member 10 coincides with the axis of the sealing member 40.

  The main shaft 52 is configured to rotate by being supplied with a driving force from a driving source (not shown). That is, the floating prevention member 10 also rotates with the rotation of the main shaft 52. Further, a valve 56 is provided at the end of the main shaft 52 on the side opposite to the side on which the anti-floating member 10 is attached. By opening and closing the valve 56, the liquid can be supplied into the cylindrical portion 24 via the check valve 34 provided on the end plate 26 of the floating prevention member 10.

  Next, as shown in FIG. 7B, the main shaft 52 of the boring machine 50 is rotated. Thereby, the float prevention member 10 also rotates with the rotation of the main shaft 52. Here, a drilling member 28 is attached to the tip of the cylindrical portion 24 of the anti-floating member 10. Then, the main shaft 52 of the boring machine 50 is moved toward the outer wall 18 a side of the shaft main body 16, that is, toward the thin plate 38 in a state where the anti-floating member 10 is rotated. In addition, since the cylindrical part 24 is pivotally supported by the sealing member 40, the rotational accuracy of the cylindrical part 24 is maintained.

  When the excavation member 28 provided on the distal end side of the tubular portion 24 comes into contact with the thin plate 38 in a state where the floating prevention member 10 is rotated, the excavation member 28 cuts the thin plate 38. At this time, the valve 56 is opened, and water is supplied to the contact portion between the excavation member 28 and the thin plate 38 via the check valve 34 and the tubular portion 24 to cool the excavation member 28. 7A shows that the valve 56 is in a closed state, and FIG. 7B shows that the valve 56 is in an open state.

  Next, as shown in FIGS. 8A and 8B, when the excavating member 28 cuts the thin plate 38 by cutting the thin plate 38, the tubular portion 24 digs toward the natural ground outside the thin plate 38. Start. The thin plate 38 a cut out in a cylindrical shape enters the cylindrical portion 24 because the diameter of the thin plate 38 a cut out is smaller than the inner diameter size of the cylindrical portion 24. The cylindrical portion 24 digs outward from the outer wall 18 a and protrudes, and a natural mountain corresponding to the hollow portion of the cylindrical portion 24 enters the cylindrical portion 24. Accordingly, the thin plate 38 a is also moved from the distal end side to the proximal end side in the cylindrical portion 24.

  At this time, the valve 56 is in an open state, and water is supplied into the cylindrical portion 24 through the check valve 34. In FIG. 8B, this water flows from the proximal end 24b to the distal end 24a along the inner peripheral surface of the cylindrical portion 24, and the excavating member 28 is moved from the distal end 24a. The excavated earth and sand are pushed along the outer peripheral surface of the cylindrical portion 24 to the end portion 24b on the base end side.

  And the said water is discharged | emitted from the water stop valve 46 through the space 42 and the drainage channel 44 with the earth and sand swept away. Since the cutting edge diameter of the excavation member 28 is set larger than the outer diameter of the cylindrical portion, a gap is formed between the outer peripheral surface of the cylindrical portion and the surrounding natural ground, and the earth and sand excavated by the excavation member 28 is formed. Can be improved.

  Next, as shown in FIG. 9A, the boring machine 50 is in a state where the flange portion 30 of the end plate 26 and the inner wall 18b of the side wall 18 are in contact with each other, that is, in a state where the cylindrical portion 24 protrudes from the outer wall 18a by a predetermined amount. The rotation of the main shaft 52 is stopped. At this time, the valve 56 is closed, and the supply of water into the cylindrical portion 24 is stopped.

  Then, the inner wall 18 b of the side wall 18 and the flange portion 30 of the end plate 26 are welded over the entire circumference in the circumferential direction of the flange portion 30. Thereby, the float prevention member 10 is fixed to the side wall 18.

  Next, as shown in FIG. 9B, the valve 56 is opened again, and the grout material 48 is injected into the cylindrical portion 24. The grout material 48 injected into the tubular portion 24 flows from the proximal end portion 24b to the distal end portion 24a along the inner peripheral surface of the tubular portion 24. Then, the grout material 48 flows from the distal end 24 a to the proximal end 24 b along the outer peripheral surface of the tubular portion 24 through the periphery of the excavating member 28. Due to the flow of the grout material 48, the water around the tubular portion 24 and the remaining excavated earth and sand are discharged from the water stop valve 46.

  And the valve | bulb 56 is closed and the grout material 48 of the inner peripheral surface side of the cylindrical part 24 and the outer peripheral surface side of the cylindrical part 24 is solidified. Thereafter, the grout material 48 is also injected from the water stop valve 46 side, and the grout material 48 is filled into the space 42 and the drainage channel 44 and solidified. Then, the water stop valve 46 is closed.

  Thereafter, as shown in FIG. 6, the fastening member 54 is loosened from the end plate 26 to remove the main shaft 52 of the boring machine 50, and the installation process at the attachment portion 36 of the shaft main body 16 of the anti-floating member 10 is completed.

<<< Modification of the first embodiment >>>
(1) In this embodiment, the anti-floating member 10 is arranged every 60 degrees in the circumferential direction of the shaft main body 16 (see FIG. 2), but according to the buoyancy F3 (see FIG. 1) acting on the shaft main body 16 You may arrange | position by increasing / decreasing the number of the float prevention members 10 in the circumferential direction.
(2) In this embodiment, the number of columns of the float prevention members 10 provided in the axial direction of the shaft main body 16 is two, but instead of this configuration, the rows of the float prevention members 10 provided in the axial direction of the shaft main body 16 May be increased or decreased according to the buoyancy F3 (see FIG. 1) acting on the shaft main body 16.
(3) In this embodiment, the shaft main body 16 is configured by stacking a plurality of steel casings 22. For example, a plurality of segments, which are arc-shaped structures formed of steel materials, are connected to form a ring-shaped casing. It may be configured as a caisson that is press-fitted into the ground.
(4) In this embodiment, the cutting edge diameter on the inner peripheral side of the excavating member 28 is set smaller than the inner diameter dimension of the cylindrical portion 24. Instead of this configuration, the cutting edge diameter on the inner peripheral side of the excavating member 28 is It is good also as the same dimension as the internal-diameter dimension of the shape part 24. FIG.

(5) In the present embodiment, the float prevention member 10 is installed in the shaft 12 after draining the water in the shaft main body 16, but according to the drainage condition in the shaft main body 16 instead of this configuration. It is good also as a process of installing the floating prevention member 10 in the shaft 12.

  Specifically, with reference to FIGS. 12 and 13, the bottom slab 20 (underwater concrete) (see FIG. 12) is placed after the housing 22 has been set. At this time, the shaft main body 16 is filled with water (see the hatched portion in the shaft main body 16 in FIG. 12). A float 62 is installed on the surface of the water in the shaft main body 16. A boring machine 50 is provided on the float 62. Further, although not shown, the float 62 is configured to be movable up and down along the axial direction of the shaft main body 16 in accordance with the displacement of the water surface in the shaft main body 16.

  First, as shown in FIG. 12, the water in the shaft main body 16 is drained, and the liquid level of the water in the shaft main body 16 is lowered from the ground surface toward the bottom plate 20. At this time, the level of water in the shaft main body 16 is antagonized by the buoyancy F3 acting on the shaft main body 16 due to groundwater, the weight of the shaft main body 16 and the weight of water in the shaft main body 16, and the shaft main body 16 does not rise. Set to position. Then, the floating prevention member 10 is installed on the shaft main body 16 by the boring machine 50, and the floating prevention member 10 is projected outward from the side wall 18 of the shaft main body 16.

  Thereby, the shaft main body 16 receives the resistance force F4 which acts on the floating prevention member 10 from a natural ground. As a result, the water level in the shaft main body 16 can be further lowered. That is, as shown in FIG. 13, up to a position where the buoyancy F3 acting on the shaft main body 16 due to groundwater and the total of the weight of the shaft main body 16, the weight of the water in the shaft main body 16 and the resistance force F4 of the anti-floating member 10 antagonize. The level of water in the shaft main body 16 can be lowered. Then, the floating prevention member 10 is installed again on the shaft main body 16, and the floating prevention member 10 is projected outward from the side wall 18 of the shaft main body 16.

  Next, the above process is repeated until the water in the shaft main body 16 is completely drained. As a result, the water in the shaft main body 16 is completely drained, and the sum of the weight of the shaft main body 16 and the resistance force F4 of the anti-floating member 10 is equal to or greater than the buoyancy F3, so that the shaft 12 has a predetermined depth in the soil. Retained.

■■■ Second Example ■■■■
A second embodiment of the anti-floating member 10 will be described with reference to FIG. This embodiment is different from the first embodiment in that the periphery of the flange portion 30 of the floating prevention member 10 in the attachment portion 58 is raised to the same position as the rear end of the end plate 26 on the inner wall 18b of the shaft main body 16.

  As shown in FIG. 10, a plurality of attachment portions 58 are provided on the side wall 18 of the shaft main body 16. In the attachment portion 58, the inner end 58a of the shaft main body 16 is located inside the shaft main body 16 with respect to the inner wall 18b. When the anti-floating member 10 is attached to the attachment portion 58 so as to protrude from the outer wall 18a, the protrusion amount of the end portion 58a of the attachment portion 58 from the inner wall 18b is flush with the rear end of the end plate 26. Is set to

  In this embodiment, the end portion 58a of the mounting portion 58 and the outer peripheral portion of the flange portion 30 of the end plate 26 are welded over the entire circumference. The end portion 58 a contacts the flange portion 30 on the outer side in the radial direction of the flange portion 30, and restricts the displacement of the end plate 26 in a direction intersecting the axial direction of the end plate 26. In FIG. 10, a black triangle between the end plate 26 and the end portion 58 a of the attachment portion 58 indicates a welded portion between the end plate 26 and the end portion 58 a of the attachment portion 58.

  That is, the attachment portion 58 not only contacts the surface of the flange portion 30 on the cylindrical portion 24 side, but also contacts the side of the flange portion 30. Therefore, the contact area between the shaft main body 16 and the floating prevention member 10 can be increased, and the force acting on the tubular portion 24 is more widely dispersed, so that the stress per unit area can be reduced. As a result, the float prevention member, for example, allows a force larger than the force from the ground that acts on the tubular portion that is allowed when only the end portion of the tubular portion is supported by the shaft. Can do. Accordingly, it is possible to improve the proof stress of the floating prevention member.

■■■ Third Example ■■■■
A third embodiment of the anti-floating member 10 will be described with reference to FIG. In the present embodiment, the mounting portion 60 is a surface opposite to the cylindrical portion 24 of the end plate 26, that is, the rear end faces the inner wall 18 b of the side wall 18 in a state where the floating preventing member 10 protrudes from the ground portion 24. It differs from the first embodiment in that it is configured to be one.

  As shown in FIG. 11, a plurality of attachment portions 60 are provided on the side wall 18 of the shaft main body 16. When the floating preventing member 10 is attached to the attachment portion 60 so as to protrude from the outer wall 18a, the inner wall 18b of the attachment portion 60 and the rear end of the end plate 26 are set to be flush with each other. And the inner wall 18b in the attaching part 60 and the outer peripheral part of the flange part 30 of the end plate 26 are welded over the perimeter of the circumferential direction. In FIG. 11, a black triangle between the end plate 26 and the inner wall 18 b of the attachment portion 60 indicates a welded portion between the end plate 26 and the inner wall 18 b of the attachment portion 60.

  As shown in FIG. 11, when the anti-floating member 10 is attached at the attachment portion 60 so as to protrude from the outer wall 18 a, the surface of the end plate 26 on the cylindrical portion 24 side contacts the sealing member 40. Further, the side portion of the flange portion 30 is in contact with the side wall 18. In other words, the inner wall 18 b of the mounting portion 60 contacts the flange portion 30 on the outer side in the radial direction of the flange portion 30, and restricts the displacement of the end plate 26 in the direction intersecting the axial direction of the end plate 26.

  Further, in the present embodiment, the floating prevention member 10 does not protrude from the inner wall 18 b of the shaft main body 16 toward the inside of the shaft main body 16. Thereby, the internal space in the shaft main body 16 can be used effectively, and it is possible to prevent the work in the shaft main body 16 from being hindered.

<<<< Modified Example of the First to Third Examples >>
(1) In each embodiment, the excavation member 28 is provided at the end 24a on the distal end side of the cylindrical portion 24 of the floating prevention member 10, but in addition to this configuration, the tubular portion is provided at the end 24a on the distal end side. It is good also as a structure which provides the member which crosses the hollow part of the part 24, and provides the excavation member 28 also in the said crossing member.
(2) In each embodiment, the inside of the cylindrical portion 24 of the anti-floating member 10 has a hollow structure, but instead of this configuration, a screw-like member is provided in the hollow portion, and the anti-floating member is rotated to form a cylinder. It is good also as a structure which mixes and stirs the earth and sand which entered in the shape part 24, and the grout material 48. By comprising in this way, the earth and sand in the cylindrical part 24 and the grout material 48 can be solidified in the uniformly mixed state, and the intensity variation in the cylindrical part 24 can be suppressed.

(3) In each embodiment, one drainage channel 44 and one water stop valve 46 are provided, but a plurality may be provided.
(4) In each embodiment, the cylindrical portion 24 and the end plate 26 in the floating prevention member 10 are integrated by welding. However, instead of this configuration, the insertion portion 32 of the end plate 26 is inserted into the cylindrical portion 24. The cylindrical portion 24 and the end plate 26 may be integrated by press-fitting, or the flange portion 30 is formed in the end portion 24b on the proximal end side of the cylindrical portion 24 by press molding or the like, so that the cylindrical portion 24 is formed. The tubular portion 24 and the end plate 26 may be integrated by attaching the insertion portion 32 and the check valve 34 to the hollow portion of the proximal end side end portion 24b by welding or press fitting.
(5) The side part of the flange part 30 in the floating prevention member 10 in the second and third examples is tapered, and the contact part of the side wall 18 that contacts the side part of the flange part 30 is also tapered. You may comprise.
(6) Although the sealing member 40 is configured as an oil seal in each embodiment, the sealing member 40 may be configured as an O-ring instead of this configuration.
(7) In each embodiment, the floating prevention member 10 is provided in the shaft 12. However, instead of this structure, the floating prevention member 10 may be provided in a horizontal shaft such as a tunnel.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

10, 100 Floating prevention member, 12 shaft, 14 ground surface, 16 shaft body,
18, 104 side wall, 18a outer wall, 18b inner wall, 20 bottom plate, 22 housing,
24 cylindrical portion, 24a distal end side, 24b, 102a proximal end,
26 end plate, 28 excavation member, 30 flange part, 32 insertion part,
34 check valve, 36, 58, 60 mounting portion, 38, 38a thin plate, 40 sealing member,
42 space, 44 drainage channel, 46 water stop valve, 48 grout material,
50 boring machine, 52 spindle, 54 fastening member, 56 valve, 58a end,
62 buoyant base, 102 load transmission member, 106 support member, 108 hole, 110 lid, 112 gap, F1, F3 buoyancy, F2, F5 force, F4 resistance force,
M1, M2 Rotation moment

Claims (12)

An anti-floating member that prevents the shaft from being lifted by submerging the body in the soil,
A cylindrical portion protruding into the soil from the shaft,
An end plate having a flange portion which is provided integrally with the end portion on the shaft side in the tubular portion and fixed in contact with the inner wall of the shaft;
A part of the end plate enters the cylindrical part at the end of the cylindrical part on the shaft side,
A vertical shaft floating prevention member characterized by that. The shaft lifting prevention member according to claim 1, wherein the end plate includes a valve capable of injecting a grout material into the cylindrical portion in a state where the cylindrical portion protrudes into the soil.
A vertical shaft floating prevention member characterized by that. In the shaft prevention member according to claim 1 or 2 , a drilling member is provided at a tip of the cylindrical portion.
A vertical shaft floating prevention member characterized by that. In the shaft prevention member according to claim 3 , the excavation member is formed such that a diameter of a cutting edge circle formed by the excavation member is larger than an outer diameter of the cylindrical portion.
A vertical shaft floating prevention member characterized by that. The shaft is constructed by sinking a frame in the soil, and is provided with the floating prevention member according to any one of claims 1 to 4 , wherein the shaft is provided with an interval in an axial direction and a circumferential direction of the shaft. Provided with a plurality of anti-floating member mounting portions provided,
The floating prevention member mounting portion is a thin plate constituting a part of the outer wall of the shaft,
A sealing member disposed near the inner wall of the shaft and facing the thin plate;
Have
The sealing member surrounds and holds the end portion on the end plate side of the tubular portion in a state where the thin plate penetrates the tubular portion of the anti-floating member into the soil,
The end plate is fixed to the inner wall of the shaft,
A vertical shaft provided with a floating prevention member. The shaft provided with the anti-floating member according to claim 5 , wherein an end of the end plate opposite to the side where the tubular portion is provided is flush with an inner wall of the shaft.
A vertical shaft provided with a floating prevention member. A shaft constructed by sunk a body in the soil , and is provided integrally with a tubular portion protruding from the shaft into the soil, and an end of the tubular portion on the shaft side, and An end plate having a flange portion fixed to the inner wall of the shaft, and a float prevention member for preventing the shaft from being lifted,
And a plurality of document retaining member mounting portion provided at intervals in the axial direction and the circumferential direction of the shafts,
The floating prevention member mounting portion is a thin plate constituting a part of the outer wall of the shaft,
A sealing member disposed near the inner wall of the shaft and facing the thin plate;
Have
The sealing member surrounds and holds the end portion on the end plate side of the tubular portion in a state where the thin plate penetrates the tubular portion of the anti-floating member into the soil,
The end plate is fixed to the inner wall of the shaft ,
The end of the end plate opposite to the side where the tubular portion is provided is flush with the inner wall of the shaft.
A vertical shaft provided with a floating prevention member. A shaft comprising the float prevention member according to any one of claims 5 to 7 , wherein a space surrounding the cylindrical portion is formed between the thin plate and the sealing member, and a grout is formed in the space. The material is filled,
A vertical shaft provided with a floating prevention member. In the shaft provided with the float prevention member according to any one of claims 5 to 8 , the sealing member is an oil seal.
A vertical shaft provided with a floating prevention member. A shaft constructed by sunk a body in the soil , and is provided integrally with a tubular portion protruding from the shaft into the soil, and an end of the tubular portion on the shaft side, and An end plate having a flange portion fixed to the inner wall of the shaft, and a float prevention member for preventing the shaft from being lifted,
And a plurality of document retaining member mounting portion provided at intervals in the axial direction and the circumferential direction of the shafts,
The floating prevention member mounting portion is a thin plate constituting a part of the outer wall of the shaft,
A sealing member disposed near the inner wall of the shaft and facing the thin plate;
Have
The sealing member surrounds and holds the end portion on the end plate side of the tubular portion in a state where the thin plate penetrates the tubular portion of the anti-floating member into the soil,
The end plate is fixed to the inner wall of the shaft ,
The sealing member is an oil seal;
A vertical shaft provided with a floating prevention member. The method for installing a float prevention member according to any one of claims 1 to 4 in a vertical shaft constructed by submerging a frame in the soil, wherein an interval between the vertical axis and the circumferential direction of the vertical shaft is set. In the plurality of anti-floating member mounting portions provided, the tubular portion of the anti-floating member, which includes a drilling member at the tip, is passed through the sealing member provided in the anti-floating member mounting portion, and the cylindrical portion is rotated. Excavating a thin plate constituting a part of the outer wall of the shaft in the anti-floating member attaching portion;
A step of penetrating through the thin plate toward the soil outside the shaft and projecting the tubular portion from the outer wall of the shaft;
Fixing the end plate of the anti-floating member to the inner wall of the shaft,
To install a float prevention member in a vertical shaft including In the installation method of the float prevention member in the shaft according to claim 10, a step of injecting a grout material into the cylindrical portion through a valve provided in the end plate;
Injecting the grout material into a space formed between the thin plate and the sealing member in the anti-floating member mounting portion;
To install a float prevention member in a vertical shaft including

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