JP2009281017A - Spiral rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spiral rod which has a discharge opening for supplying water to a hydraulic bulk load supplied concurrently with the drilling of a hole, and which makes a column body with homogeneous strength surely constructed with proper reproducibility by preventing the column body from being poorly constructed due to clogging. <P>SOLUTION: Conveying screws 3a and 3b are provided on the outside; a water passage 5 is provided on the inside; a terminal end of the water passage 5 is provided with one or more discharge opening lines wherein the discharge openings 4a with an opening length of less than 10 mm along a circumferential direction are disposed in the circumferential direction; and an opening ratio, which is expressed by the sum of the opening length along the circumferential direction of all the discharge openings 4a, opened in the axial arbitrary position of the spiral rod 1, and the circumferential length of an outside surface of a main body 2, is set at 50% or less in the above position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spiral rod used in a construction method for constructing a pillar body in a ground in order to strengthen the ground in an unstable ground such as a loose sand ground, a viscous ground, or a multi-layer ground in which different ground layers are laminated.

  Loose sand ground, clay soil, and multi-layered ground where different layers are stacked will collapse in the event of an earthquake or flood, causing damage to structures or roads and other structures built on the ground, and affecting the surrounding area. There is a risk of causing.

  Therefore, a means for strengthening the ground by constructing hard pillars in the ground has been taken. As a method for constructing such a column body, the present inventor has developed a hollow spiral rod having a conveying screw on the outside while rotating the conveying screw so that the conveying direction of the conveying screw coincides with the press-fitting direction of the spiral rod. At the same time, a hydraulic bulk load was supplied to the conveying screw, and water was supplied to the hydraulic bulk load from the end of the spiral rod through the hollow portion of the spiral rod to cure it.

  However, in the above construction method, there is a possibility that the water supply port provided at the tip of the spiral rod may be clogged by the bulk load conveyed by the screw or the surrounding earth and sand. When the water supply port is clogged, the water is not uniformly discharged to the surrounding bulk load, and a column having uniform strength cannot be constructed. This clogging cannot be easily resolved during the process, for example, it is possible to force drainage with a temporary high pressure, but it is possible to detect clogging instantaneously during construction and adjust the water pressure. It was difficult, and the amount of water was not constant, so it became a non-homogeneous column, making it difficult to cope with it.

  In Patent Document 1, a drilling rod provided with a drilling blade and a stirring blade is provided with a solidified material liquid discharge port, and the solidified material liquid is supplied to the soil cut by the drilling rod and stirred to form a columnar column in the ground. In order to prevent clogging of the solidification material liquid discharge port, a valve body that operates by magnetic action is disposed at the solidification material liquid discharge port, and when the solidification material liquid is unnecessary, A structure is disclosed in which the discharge port is closed by magnetic action, and when the solidifying material liquid is required, the valve body is moved by the discharge pressure of the solidifying material liquid to open the discharge port.

JP-A-7-138936

  However, the discharge port of the excavating rod of Patent Document 1 also opens the solidified material liquid discharge port by moving the valve body downward when earth or sand or loose load or a mixture thereof is clogged below the valve body. You will not be able to.

  An object of the present invention is a spiral rod having a discharge port for supplying water to a hydraulic bulk load supplied at the same time as excavation of a drilling hole, which prevents a poor construction of a column body due to clogging and has strength. An object of the present invention is to provide a spiral rod for constructing a homogeneous column with good reproducibility and reliability.

The first of the present invention is a spiral rod provided with a conveying screw on the outside, and provided with a water passage that leads from the rear end to the outer surface near the tip,
The end of the water passage on the outer surface near the tip of the spiral rod is
At least one discharge port having an opening length along the circumferential direction of the outer surface of less than 10 mm and at least one discharge port line arranged in the circumferential direction,
At an arbitrary position in the axial direction of the spiral rod, the opening ratio represented by the sum of the opening lengths along the circumferential direction of all the discharge ports opening at the outer surface of the spiral rod is 50% or less. It is characterized by that.

The second of the present invention is a spiral rod provided with a conveying screw on the outside, and provided with a water passage that leads from the rear end to the outer surface near the tip,
The end of the water passage on the outer surface near the tip of the spiral rod is
At least two discharge ports having an opening length of less than 10 mm along the circumferential direction of the outer surface, and at least one row of discharge port lines arranged spirally;
The sum of the opening length in the direction along the spiral of all the discharge ports opened on the spiral with respect to the length of the spiral for one round in the circumferential direction when viewed from the rear end of the spiral rod in the discharge port line of each row The aperture ratio indicated by is 50% or less,
At an arbitrary position in the axial direction of the spiral rod, the opening ratio represented by the sum of the opening lengths along the circumferential direction of all the discharge ports opening at the outer surface of the spiral rod is 50% or less. It is characterized by that.

  According to the present invention, clogging of discharge ports due to loose loads or earth and sand is unlikely to occur, and by providing discharge ports in a broken line shape, water is discharged from other discharge ports even when there are clogged discharge ports. Therefore, water can be supplied uniformly and reliably to the bulk load. Therefore, there is no possibility of causing a poor construction of the column, and a column having a uniform strength can be reliably constructed at a predetermined position.

  The column construction method using the spiral rod according to the present invention basically uses a hollow spiral rod having a conveying screw on the outside so that the conveying direction of the conveying screw coincides with the press-fitting direction of the spiral rod. There are a step of press-fitting into the ground while rotating, and a step of pulling-up while rotating the spiral rod in the same direction as the press-fitting after the tip of the spiral rod reaches a predetermined depth. In the press-fitting step, a hydraulic bulk load is supplied to the conveying screw. Since the conveying direction of the conveying screw coincides with the press-fitting direction of the spiral rod, the hydraulic bulk load supplied to the conveying screw is filled in the drilling hole excavated by the spiral rod with the press-fitting of the spiral rod. Go. Also, the earth and sand excavated with the spiral rod is pressed and hardened with the press-fitting of the spiral rod without being transported to the outside because the transport direction of the transport screw matches the press-fitting direction of the spiral rod, A dense drilling wall is formed. That is, in the column construction method according to the present invention, since the earth and sand of the ground for constructing the column is not discharged to the outside, the disposal operation of the earth and sand is unnecessary.

  Furthermore, in the column construction method according to the present invention, in the pulling-up step, water is discharged from the vicinity of the tip of the spiral rod to supply water to the hydraulic loose load. The hydraulic bulk load is hardened by the supplied water. Such water is supplied to the hydraulic bulk load continuously or at a desired timing.

  The present invention is a spiral rod provided with a water passage for supplying such water uniformly to a hydraulic bulk load, and a discharge port for discharging water is clogged with earth or sand, a bulk load, or a mixture thereof. It is a solution to the problem.

  In the spiral rod of the present invention, preferably, the discharge ports are configured in a broken line shape, and the first mode in which the discharge ports are arranged in the circumferential direction on the outer surface of the spiral rod and the second mode in which the discharge ports are arranged in a spiral shape. It is divided into.

  Hereinafter, the present invention will be described in detail with preferred embodiments for each.

  FIG. 1 is a front view of the vicinity of the tip of a preferred example of the first form of the spiral rod of the present invention, FIG. 2 is a schematic cross-sectional view thereof, and (a) is a vertical cross-sectional view along the central axis. (B) is an AA 'cross-sectional schematic diagram in (a), (c) is a BB' cross-sectional schematic diagram of (a).

  As shown in FIGS. 1 and 2, the spiral rod 1 of the present invention has conveying screws 3 a and 3 b outside the main body 2. In this example, the conveying screws 3a and 3b have a double spiral structure, but a single spiral structure may be used.

  As shown in FIG. 2, the spiral rod 1 of the present invention has a water passage 5 extending from the rear end portion toward the outer surface in the vicinity of the front end portion inside the main body 2. A discharge port line is formed on the outer surface in the vicinity of the tip.

  In the first embodiment of the present invention, there are at least one discharge port line in which at least one discharge port 4a is arranged in the circumferential direction.

  FIG. 3A is a diagram illustrating an arrangement example of the discharge ports 4 a in the first embodiment, and is a development view of the vicinity of the discharge port line of the main body 2. In FIG. 3A, (a) is an example in which twelve discharge ports 4 a are arranged with their upper and lower ends aligned in the circumferential direction, similar to the example of FIGS. . (B) is an example in which the same discharge port lines as in (a) are arranged in two rows in the axial direction of the spiral rod. (C) is an example in which the discharge port lines are arranged in a row, but the upper and lower ends are alternately arranged one by one. In this embodiment, as shown in (c), even if the upper and lower ends of the discharge ports 4a are not aligned, a configuration in which the discharge ports 4a are arranged in a substantially straight line is defined as one row of discharge port lines.

  In the present invention, the opening length (L2) along the circumferential direction of the outer side surface of the main body 2 of the discharge port 4a is less than 10 mm, and the circumference of the outer side surface of the spiral rod is at an arbitrary position in the axial direction of the spiral rod. The opening ratio represented by the sum of the opening length (L2) along the circumferential direction of all the discharge ports opening at the position with respect to the length (L1) is 50% or less. That is, in FIG. 3A, the aperture ratio in the circumferential direction is (L2 × 12 / L1) in any of the examples (a) to (c).

  In the present invention, by making the opening length (L2) of the discharge port 4a along the circumferential direction as small as less than 10 mm, the discharge port 4a can be prevented from being clogged with earth and sand or loose loads. The thickness is preferably 5 mm or less, and 2 mm or more in consideration of workability.

  Further, in the present invention, when one discharge port is opened in the main body 2 having a small diameter, when the above-described opening rate is more than 50%, the discharge port opens widely in the circumferential direction. Such an outlet tends to be clogged. Further, even when two or more discharge ports 4a are provided in the main body 2 having a small diameter, if the opening ratio exceeds 50%, the interval between adjacent discharge ports becomes narrow. The strength of No. 2 becomes low, and it becomes easy to break. Therefore, in the present invention, the opening ratio indicated by the sum of the opening lengths of all the discharge ports with respect to the circumferential length in the circumferential direction needs to be 50% or less.

  In FIG. 1 and FIG. 2, for convenience of manufacturing, a discharge port ring 4 provided with a discharge port 4 a as a through hole is fitted into a recess provided in the main body 2, and the spiral rod 1 is directed from the rear end portion to the front end portion of the main body 2. The water flow path 5 extending in the axial direction is branched into a cross-shaped planar shape in the vicinity of the tip, and a gap is provided between the ring 4 and the main body 2 at a position where the tip of the cross reaches the recess. Thus, water is uniformly supplied to the plurality of discharge ports 4a. In particular, in the configuration of this example, the discharge port 4a is positioned below the passage portion that branches into the cross shape of the water passage 5 and extends in the horizontal direction, and water supplied from the water passage 5 is from the discharge port 4a. The discharge port 4a is less likely to be clogged because it is easy to be discharged, and it is difficult for loose loads or earth and sand to enter the discharge port 4a from the outside. In addition, this invention is not limited to the said structure.

  Further, if the height of the discharge port 4a (the axial opening length of the spiral rod) is increased, the entire opening area is increased and water is easily discharged. However, if the height of the discharge port 4a is too high, the main body In order to increase the overall opening area, it is preferable that the discharge port lines have two or more rows as shown in FIG. 3-1 (b). When a plurality of discharge port lines are provided in this way, the opening length and opening ratio of the discharge ports 4a in each row are within a range satisfying the opening length and opening ratio in the circumferential direction at an arbitrary position of the spiral rod. If so, they may be the same or different. In other words, in FIG. 3B, the discharge port 4a is provided so as to satisfy the above-described opening length and opening ratio in the circumferential direction on the CC ′ line and the DD ′ line, respectively. That's fine. In each row, the opening length, height, and interval of the discharge ports 4a do not have to be the same, and two or more shapes and dimensions may be combined.

  In FIG. 3B, the positions of the discharge ports 4a in the circumferential direction are made to coincide with each other on the upper and lower discharge port lines, but they may be arranged alternately, and the discharge ports of the respective discharge port lines. The number, shape and interval of 4a may be different from each other.

  FIG. 3-1 (c) is an example in which the positions of the discharge ports 4a in the vertical direction (axial direction of the spiral rod) are staggered one by one as described above.

  Also in FIGS. 3A and 3B, the opening length, height, and interval of the discharge port 4a do not have to be the same in the CC ′ line, and two or more types are possible. A combination of dimensions may be used.

  In this embodiment, the discharge port 4a may be provided so that the aperture ratio is 50% or less regardless of whether the C-C ′ line is set in any axial direction of the spiral rod.

  Next, a second embodiment of the present invention will be described. The configuration of the second embodiment is the same as that of the first embodiment except for the arrangement of the discharge ports 4a, and the description thereof is omitted.

  FIG. 3B is a diagram illustrating an arrangement example of the discharge ports 4 a in the second embodiment, and is a development view of the vicinity of the discharge port line of the main body 2. In FIG. 3A, (a) is an example in which twelve discharge ports 4a are arranged in a spiral shape, and each discharge port 4a is arranged along a spiral indicated by the E-E 'line. The discharge port line is one row. (B) is an example in which two discharge port lines similar to (a) are arranged along the double helix of the E-E 'line and the GH-G' line. (C) is an example in which the discharge port lines are arranged in a line, but two discharge ports are arranged along the E-E 'line in units of two in a state where the discharge ports are arranged in the same position in the vertical direction. In this embodiment, as shown in (c), even if the positional relationship of the discharge ports 4a with respect to the EE ′ line is not the same, the entire discharge ports 4a are arranged in a substantially spiral shape and adjacent to each other. When the opening areas in the vertical direction partially overlap, the discharge ports 4a that open to the EE ′ line are all included in one row of discharge port lines.

  Also in this embodiment, for the same reason as in the first embodiment, the opening length (L2) of the discharge port 4a along the circumferential direction is less than 10 mm. Furthermore, for the same reason as in the first embodiment, at any position in the axial direction of the spiral rod, the circumferential length (L1) of the outer surface of the spiral rod is along the circumferential direction of all the discharge ports opening at the position. The aperture ratio indicated by the sum of the aperture lengths (L2) is 50% or less. That is, in FIG. 3A, the aperture ratio is (L2 × 4 / L1) in the FF ′ line, and in FIG. 3B, the aperture ratio is (L2) in the FF ′ line. In (c), the aperture ratio is (L2 × 4 / L1) in the FF ′ line.

  In this embodiment, the discharge port 4a is provided so that the aperture ratio in the circumferential direction is 50% or less regardless of whether the F-F ′ line is set in any axial direction of the spiral rod.

  Further, in this embodiment, all the discharge ports opened on the spiral with respect to the length of the spiral for one round (= 360 °) in the circumferential direction when viewed from the rear end of the spiral rod in one row of discharge port lines. The aperture ratio indicated by the sum of the aperture lengths in the direction along the spiral is 50% or less. That is, in FIGS. 3-2 (a) and 3 (c), along the EE ′ line of all the discharge ports 4a arranged on the EE ′ line with respect to the length (S1) of the EE ′ line. The aperture ratio (= S2 × 12 / S1) indicated by the sum of the aperture lengths (S2) is 50% or less. Further, in FIG. 3B, as in (a) and (c), all the discharge ports 4a arranged on the EE ′ line with respect to the length (S1) of the EE ′ line. The aperture ratio (= S2 × 12 / S1) indicated by the sum of the aperture lengths (S2) along the line EE ′ is 50% or less, and at the same time, the length of the GHG ′ line (S1) The aperture ratio (= S2 × 12 / S1) represented by the sum of the aperture lengths (S2) along the HG-G ′ line of all the discharge ports 4a arranged on the GH-G ′ line is 50. % Or less. When the aperture ratio exceeds 50%, the interval between the adjacent discharge ports becomes narrow, so that the strength of the main body 2 is lowered in the discharge port line and is easily damaged.

  In the second embodiment of the present invention, the spiral inclination angle of the discharge port line (the angle formed by the EE ′ line with respect to the FF ′ line in FIG. 3-2) is not particularly limited. However, in consideration of ease of manufacture, it is preferable to match the inclination angle of the spiral at the position where the conveying screws 3a and 3b are attached to the main body 2.

  3-2 (a) and 3 (b), the opening length, height, and interval of the discharge port 4a need not be the same in the EE ′ line, and two or more types of shapes, It may be configured by combining dimensions.

  Further, in FIG. 3B, the opening length, height, and interval of the ejection ports 4a need to be the same in each row of the EE ′ line and the GHG ′ line. Alternatively, two or more shapes and dimensions may be combined.

  Furthermore, in FIG. 3-2 (b), the positions of the circumferential discharge ports 4a are made to coincide with each other above and below the double helix, but they may be arranged alternately, and the discharge ports of the respective discharge port lines. The number, shape and interval of 4a may be different from each other.

  In this example, a rectangular shape is exemplified as the shape of the discharge port 4a. However, in the present invention, the shape is not limited to this, and it may be a circle, an ellipse, or the like.

  The hydraulic bulk load used in the method for constructing a column using the spiral rod of the present invention is composed of a cement-based solidified material as a hydraulic component and sand as an aggregate, and is generally kneaded by adding water thereto. Things are mortar. Sand having a particle size of 20 mm or less, preferably 5 mm or less is used. The cement-based solidifying material is obtained by adding an additive such as a hardening accelerator to cement or lime as necessary. The cement-based solidifying material and sand are blended at a weight ratio of 1: 2 to 1: 3.

  The column construction method using the spiral rod of the present invention will be described below with reference to FIG.

  A hopper 11 is disposed so as to surround the spiral rod 1, and a hydraulic bulk load 12 is stored in the hopper 11. In this state, the spiral rod 1 is press-fitted while rotating so that the conveying direction of the conveying screws 3a, 3b coincides with the press-fitting direction (arrow B direction) of the spiral rod 1 (arrow A direction) [FIG. ]. That is, in FIG. 4, when viewed from the rear end of the spiral rod 1, the conveying screws 3a and 3b are formed clockwise from the rear end to the front end of the spiral rod 1, and the spiral rod 1 is shown in FIG. As shown in a), when rotated counterclockwise (arrow A) as viewed from the rear end of the spiral rod 1, the transport direction of the transport screws 3a and 3b is the direction from the rear end to the front end of the spiral rod 1. This coincides with the press-fitting direction (arrow B direction) of the spiral rod 1. That is, normally, the conveyance screws 3a and 3b are rotated in the opposite direction to facilitate press-fitting, whereby the hydraulic bulk load 12 stored in the hopper 11 is transferred to the conveyance screws 3a and 3b. 3b and conveyed toward the press-fitting direction, that is, toward the tip of the spiral rod 1. Further, since the conveying direction of the conveying screws 3 a and 3 b is the same as the press-fitting direction of the spiral rod 1, there is no possibility that the earth and sand of the ground will be discharged into the hopper 11.

  When the tip of the spiral rod 1 reaches a predetermined depth (FIG. 4B), a hydraulic loose load 12 is formed in the gap between the inner wall of the hole 14 formed by press-fitting the spiral rod 1 and the spiral rod 1. Filled.

  Next, the spiral rod 1 is pulled upward (arrow B ′ direction) while rotating in the same direction (arrow A direction) as in press-fitting. That is, since the conveying direction of the conveying screws 3a and 3b is opposite to the pulling direction of the spiral rod 1 (arrow B ′ direction), the hydraulic bulk load 12 once supplied into the drilling hole 14 is There is no fear of being discharged out of the hole 14 by pulling up. Further, preferably, when the spiral rod 1 is pulled up, the hydraulic bulk load 12 can be more densely filled in the hole 14 by supplying the hydraulic bulk load 12 to the conveying screws 3a and 3b. In particular, since the hydraulic loose load 12 is supplied at the tip of the spiral rod 1 at the same time that the tip is pulled up, the hydraulic loose load 12 can be filled densely and uniformly.

  Further, in this process, water is supplied to the water passage 5 formed in the main body 2 of the spiral rod 1, water is discharged from the discharge port 4 a near the tip, and water is supplied to the hydraulic loose load 12. In addition, you may add additives, such as a hardening accelerator, to the water to supply.

  Since the spiral rod 1 of the present invention prevents clogging due to earth and sand and loose loads at the discharge port 4a which is the end of the water passage 5, water is reliably supplied to the hydraulic loose load 12 in the hole 14. can do.

  After the spiral rod 1 is completely pulled up, the hydraulic loose load 12 is hardened by the supplied water, and a strong column 15 is built in the ground 13 [FIG. 4 (d)].

  Four types of spiral rods of the first embodiment illustrated in FIGS. 1 and 2 were produced by changing the opening length and the number of discharge ports 4a. The outer diameter of the main body 2 is 60 mm, the pitch of the conveying screws 3 a and 3 b is 100 mm, the maximum diameter from the rear end to the vicinity of the front end is 120 mm, the diameter gradually decreases at the front end, 100 mm, the thickness is 6 to 9 mm, the discharge port line is The lower end of the discharge port 4a was positioned 500 m from the tip of the main body 2, the height was 5 mm, the opening length was 2 mm, 12 pieces were 5 mm, 8 pieces were 8 mm, and 8 pieces were 10 mm.

  As the hydraulic bulk load 12, a mixture of ordinary Portland cement and sand in a weight ratio of 1: 2 was used to construct a column having a diameter of 130 mm to 200 mm (average 160 mm) and a depth of 6 m. The hydraulic loose load 12 was filled with 40 kg per 1 m depth, and 3 to 6 L of water was supplied per 1 m depth. FIG. 5 shows the results of a particle size test of the sand used in this example and a mixture of the sand and cement.

  As a result, for the opening lengths of 2 mm and 5 mm, the flow rate was constant, the discharge pressure was not high, and it was constant and stable. For the opening length of 8 mm, the flow rate did not reach 2 mm and 5 mm, and the discharge pressure was high, but it was at a level where a column body that could be used practically could be constructed. On the other hand, in the case of the opening length of 10 mm, although the discharge pressure was significantly higher than 2 mm to 8 mm, the flow rate was greatly reduced and a sufficient amount of water could not be supplied. When the discharge port 4a was observed by pulling up the spiral rod 1, the discharge ports 4a having the opening lengths of 2 mm and 5 mm were hardly clogged, but some discharge ports were clogged at 8 mm. Further, the discharge ports having an opening length of 10 mm were clogged at more discharge ports than 8 mm.

  The present invention, for the purpose of strengthening the soil and the like, press-fit a spiral rod into the ground to form a borehole, and simultaneously supply a hydraulic loose load into the borehole and harden the hydraulic loose load with water. It is used in the construction method of building a column.

It is a front view of the front-end | tip part vicinity of one Embodiment of the spiral rod of this invention. It is a cross-sectional schematic diagram of the spiral rod of FIG. It is a figure which shows the example of an arrangement | sequence of the discharge outlet of the 1st form of this invention. It is a figure which shows the example of an arrangement | sequence of the discharge outlet of the 2nd form of this invention. It is process drawing of the construction method of the column using the spiral rod of FIG. It is a figure which shows the result of the particle size test of the hydraulic bulk load used in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spiral rod 2 Main body 3a, 3b Conveying screw 4 Discharge port ring 4a Discharge port 5 Water passage 11 Hopper 12 Hydraulic loose load 13 Ground 14 Drilling 15 Column

Claims (2)

A spiral rod provided with a conveying screw on the outside, and provided with a water passage leading from the rear end portion to the outer surface near the tip portion,
The end of the water passage on the outer surface near the tip of the spiral rod is
At least one discharge port having an opening length along the circumferential direction of the outer surface of less than 10 mm and at least one discharge port line arranged in the circumferential direction,
At an arbitrary position in the axial direction of the spiral rod, the opening ratio represented by the sum of the opening lengths along the circumferential direction of all the discharge ports opening at the outer surface of the spiral rod is 50% or less. Spiral rod characterized by that. A spiral rod provided with a conveying screw on the outside, and provided with a water passage leading from the rear end portion to the outer surface near the tip portion,
The end of the water passage on the outer surface near the tip of the spiral rod is
At least two discharge ports having an opening length of less than 10 mm along the circumferential direction of the outer surface, and at least one row of discharge port lines arranged spirally;
The sum of the opening length in the direction along the spiral of all the discharge ports opened on the spiral with respect to the length of the spiral for one round in the circumferential direction when viewed from the rear end of the spiral rod in the discharge port line of each row The aperture ratio indicated by is 50% or less,
At an arbitrary position in the axial direction of the spiral rod, the opening ratio represented by the sum of the opening lengths along the circumferential direction of all the discharge ports opening at the outer surface of the spiral rod is 50% or less. Spiral rod characterized by that.

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