JP2006104761A - Method of increasing strength of landslide preventive pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of increasing the strength of a landslide preventive pile capable of keeping blocks in a steel pipe in a freely movable state independently of the steel pipe even if clamp-pressed and transmitting pressure to the whole of a plurality of blocks to increase deterrent. <P>SOLUTION: In the method of increasing the strength of a restraining pile formed of a steel pipe pile by boring a borehole in a landslide slope to insert the steel pipe pile and then inserting the plurality of blocks in the steel pipe pile, the block 7 inserted in the steel pipe pile 1 has a hole in the center part, and a steel bar 11 with the lower end fixed to a bottom cover 10 fixed to the lower part of the steel pipe pile is inserted in the hole of the block. An upper cover 13 is allowed to pass through the upper end of the steel bar, and the plurality of blocks held between the bottom cover and the upper cover with the steel bar inserted through, are fastened and forcibly pressed by a fastening member 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for increasing the strength of a landslide prevention pile installed on a landslide slope, and is applicable to a pile method used in a landslide prevention construction.

  There is a pile construction method as one of the landslide prevention construction methods. Pile work is a construction method that resists sliding force and suppresses landslide movement by penetrating the moving layer in the landslide slope and installing a steel pipe pile in the borehole that reaches the fixed base rock. Conventionally, in order to prevent landslide prevention in such a pile work, after drilling a boring hole on the landslide slope, inserting a steel pipe pile into the hole, filling the inside and outside of the steel pipe pile with mortar or concrete Thus, a method of increasing the strength of the deterrent pile made of the steel pipe pile has been proposed (see, for example, Patent Document 1).

JP 2003-184100 A

  In Patent Document 1, a bottom lid is welded to the lower end of a steel pipe pile, and the steel pipe pile is built into a boring hole from the bottom lid side, and after erection, the inside and outer circumference of the steel pipe pile is filled with mortar and the like. Thereafter, a pressure plate is placed on the cured mortar and the like, and a bolt or a nut is tightened from the surface side direction to pressurize. And when filling the inside of the steel pipe pile with mortar, etc., it was provided in the canopy welded to the upper end of the steel pipe pile after inserting the middle packed concrete as a plurality of blocks manufactured in advance in the factory or the field into the steel pipe pile Tighten with bolts, forcibly pressurize between the pressure plate that contacts the tip of the bolt and the bottom lid (for example, see paragraph 0017 and FIG. 8 of the description in which the full text was corrected in the procedure amendment dated July 20, 2002) ). However, the filling concrete inserted into the steel pipe by pressurization as described above is not in a state where it can move freely integrally with the steel pipe, and the force pressed through the pressure plate is the filling concrete near the pressure plate. There is a problem that it is not transmitted evenly to the entire filling concrete and does not lead to an increase in deterrence.

  Therefore, the present invention solves the above-mentioned problems of the conventional one, and even when tightening and pressurizing, the block in the steel pipe can be kept freely movable separately from the steel pipe, and the applied pressure can be transmitted to the entire plurality of blocks. An object of the present invention is to provide a strength enhancement method for a landslide prevention pile that can increase the deterrence.

  In order to solve the above-mentioned problem, the invention according to claim 1 is to drill a boring hole on a landslide slope, insert a steel pipe pile into the hole, and then insert a plurality of blocks into the steel pipe pile. Thus, the strength of the deterrent pile made of the steel pipe pile is increased, and the block inserted into the steel pipe pile consists of a block having a hole in the center, and the hole of the block is located in the lower part of the steel pipe pile. A steel rod having a lower end fixed is passed through a fixed bottom lid, and an upper lid is passed through the upper end of the steel rod, and a plurality of steel rods are passed between the bottom lid and the upper lid. The block is forcedly pressed by tightening the block with a tightening member.

  According to a second aspect of the present invention, in the first aspect, the tightening member comprises a nut screwed into a screw formed on the upper end portion of the steel bar, and the plurality of blocks are forcibly pressurized by tightening the nut. It is characterized by that. The invention described in claim 3 is characterized in that, in claim 1 or 2, the block is a cylindrical reinforced concrete block.

  In the invention according to any one of claims 1 to 3, the block inserted into the steel pipe pile as described above is a block having a hole in the center, and the lower end is fixed to the bottom lid of the steel pipe pile in the hole of the block. The steel bar is passed through and the top lid is passed through the upper end of the steel bar, and a plurality of blocks sandwiched between the bottom lid and the top lid are fastened by the fastening member. However, the block inserted into the steel pipe can be freely moved without being integrated with the steel pipe. Therefore, the applied pressure and landslide force can be transmitted to the entire plurality of blocks, the strength of the steel pipe pile can be increased, and the deterrence can be increased. In addition, the construction cost can be kept low, and the construction cost can be reduced.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a side sectional view in which a steel pipe pile is installed on a landslide slope. Reference numeral 1 denotes a steel pipe pile, which is placed on a landslide slope 2 from its ground surface 3 toward a slip surface 4. Although only one is shown in the drawing, a plurality are usually installed at a predetermined interval in the front-rear direction of the drawing.

  The inside of the cast steel pipe pile 1 is as shown in FIG. That is, the steel pipe pile 1 has a hollow cylindrical pile body 6 having a predetermined length with an open upper end, and a bottom lid 10 is fixed to the lower end of the pile body by welding or the like. A plurality of columnar reinforced concrete blocks 7 are stacked and inserted into the pile main body 6 whose lower end is closed by the bottom lid 10. In this inserted state, the block 7 is accommodated with a slight gap from the inner peripheral surface of the pile body 6. A hole 8 having a size that allows the steel rod 11 to be inserted is formed in the center of the block 7 so as to penetrate vertically. That is, the hole 8 is formed to be considerably larger than the diameter of the steel bar 11 so that the steel bar 11 can be loosely fitted, and the block 7 can move in the axial direction through the hole 8 with the steel bar 11 as a guide. . Block 7 is prefabricated at the factory or in the field.

  When the block 7 is inserted into the pile body 6, it is inserted into the steel rod 11 whose lower end is fixed to the bottom lid 10 by sequentially inserting it from the lowermost block 7. A screw 12 is cut at the upper end of the steel rod 11, and the insertion of the block 7 is completed with the uppermost block 7 projecting the screw 12 from its upper end surface. Thereafter, the projecting screw 12 is passed through. Cover the top lid 13 as shown. After that, when a nut 15 as a tightening member is screwed onto the screw 12 and tightened, the plurality of blocks 7 are sandwiched between the bottom lid 10 and the top lid 13 and forcedly pressed.

  Next, installation of the actual steel pipe pile 1 on the landslide slope 2 will be described. When installing, first, a boring hole is drilled in the landslide slope 2. Next, the steel pipe pile 1 is inserted into the bored hole from the bottom lid 10 side of the pile body 6 and built. Next, a plurality of blocks 7 are inserted into the built-in steel pipe pile 1. When inserting, the steel rod 11 whose lower end is fixed to the bottom lid 10 is used as a guide, and the blocks 7 are sequentially inserted into the holes 8 from the upper end. I'll put it through. Then, when the inserted block 7 reaches the vicinity of the upper end opening of the pile body 6, the upper end portion of the steel rod 11 is put through the upper lid 13. Thereafter, a nut 15 is screwed onto the screw 12 of the steel bar 11 coming out of the upper lid 13 and tightened. As a result, the plurality of blocks 7 inserted into the steel pipe pile 1 are sandwiched between the bottom lid 10 and the top lid 13 and are subjected to the pressurizing force by the tightening force, but are not integrated with the steel pipe pile 1. It is kept in a freely movable state in the axial direction.

  The effect | action using the steel pipe pile 1 of the above structures is demonstrated. As shown in FIG. 3, the behavior of the steel pipe pile 1 installed on the landslide slope at the time of landslide is as shown in FIG. The pipe 18 is bent and deformed, and a tensile force 20 and a compressive force 21 act on the steel pipe pile 1. At this time, the same thing occurs in the block 7 inserted into the steel pipe pile 1. However, the pressure applied by the tightening force is always acting on the block 7 as described above, and it is not integrated with the steel pipe pile 1. Since the sliding force can be transmitted to the whole of the plurality of blocks 7 and received by the steel pipe pile 1 and the block 7, the strength of the steel pipe pile 1 can be increased and the deterrence can be increased. it can.

That is, in this embodiment, the following effects can be expected.
(1) Since the block 7 has a structure that can freely move along the steel rod 11 through the hole 8, the strain generated in the steel rod 11 can be dispersed throughout the steel rod, and the stress acting on the steel rod and the block. And local damage to the steel bars and blocks can be prevented or suppressed.
(2) Since the block 7 is composed of a plurality of pieces, when the tensile force 20 which is a weak point of concrete acts on one block, the influence of the tensile force does not affect other blocks, so the strength of the steel pipe pile 1 In addition, workability on site is also good.
(3) Only the compressive force 21 acts on the block 7 within a range where the tensile force is smaller than the force of forced pressurization, and the property that the concrete of the block 7 is strong against the compressive force can be utilized effectively. Compared to the conventional steel pipe pile, the strength of the steel pipe pile 1 can be increased by the increase in strength due to the block 7.
(4) Since the block 7 is inserted in the steel pipe pile 1 with a minimum gap (a gap necessary for the block to move freely), the compression force 21 acting on the block 7 is applied to the entire block. Transmission and the collapse of the pipe that occurs when the steel pipe pile undergoes bending deformation can be reduced, and the strength of the steel pipe pile 1 can be increased.
(5) Since the block 7 can be produced with high quality in the factory, its strength can be grasped, and the block can be incorporated into the design of the steel pipe pile 1.
(6) Construction costs can be kept low, and construction costs can be reduced.

  The length of the block 7 in the tube axis direction is preferably shorter in consideration of workability, but it is preferable that the length is as long as possible because it is better in terms of strength. The block 7 shown in this embodiment is merely an example.

  In the above-described embodiment, the nut 15 is shown as the tightening member. However, this is merely an example, and another member having the same effect may be used.

1 is a side sectional view showing an embodiment of the present invention. It is a sectional side view which shows the placement state of the steel pipe pile same as the above. It is a sectional side view which shows the behavior at the time of landslide of a steel pipe pile.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel pipe pile 2 Landslide slope 3 Ground surface 4 Slip surface 6 Pile main body 7 Block 8 Hole 10 Bottom cover 11 Steel rod 12 Screw 13 Top cover 15 Nut 17 Valley side 18 Mountain side 20 Tensile force 21 Compression force

Claims (3)

  This is a method of increasing the strength of a deterrent pile consisting of a steel pipe pile by drilling a boring hole on a landslide slope, inserting a steel pipe pile into the hole, and then inserting a plurality of blocks into the steel pipe pile. The block inserted into the steel pipe pile consists of a block having a hole in the center, and a steel rod having a lower end fixed to a bottom lid fixed to the lower part of the steel pipe pile is passed through the hole of the block. The upper lid is passed through the upper end of the steel rod, and the steel rod is passed through and forcedly pressurized by tightening a plurality of blocks sandwiched between the bottom lid and the upper lid with a fastening member. Strengthening method of landslide prevention pile.   The method for increasing the strength of a landslide prevention pile according to claim 1, wherein the tightening member comprises a nut screwed into a screw formed on an upper end portion of the steel rod, and the plurality of blocks are forcibly pressurized by tightening the nut.   The method for enhancing the strength of a landslide prevention pile according to claim 1 or 2, wherein the block is a cylindrical reinforced concrete block.

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