KR20100093117A - Steel pipe for reinforcing foundation, method of reinforcing foundation using the same, and method of reinforcing structure - Google Patents

Abstract

The ground reinforcing steel pipe of the present invention is a ground reinforcing steel pipe which is poured into the ground and injects the injection material into the ground, wherein the recessed portion and the smoothed portion disposed on the outer circumferential surface thereof, and the recessed portion or the smoothed portion, It has a plurality of through-holes passing through the ground reinforcing steel pipe.

Description

STEEL PIPE FOR REINFORCING FOUNDATION, METHOD OF REINFORCING FOUNDATION USING THE SAME, AND METHOD OF REINFORCING STRUCTURE}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a ground reinforcing steel pipe suitable for use in a pore polling method, tunnel reinforcement method, and the like in tunnel construction, a ground reinforcing method using the same, and a method of reinforcing a structure such as a concrete foundation.

This application claims priority based on Japanese Patent Application No. 2008-009570 for which it applied to Japan on January 18, 2008, and uses the content here.

For example, in a tunnel construction in a soft ground, the fore polling method which embeds steel pipes in order to reinforce the ground is often adopted. In this method, the steel pipe is externally fitted to the drill rod provided with the bit at the distal end and drilled. Then, when the drilling of the predetermined depth is carried out, the drill rod is removed while leaving the steel pipe intact, and an injection material such as mortar is injected into the steel pipe. In the body part of a steel pipe, many through-holes which penetrate in and out are perforated. The injection material injected therein penetrates into the ground through the through hole and is solidified. As a result, the soft ground is strengthened. A lot of patent applications are made about the pore-polling method (for example, refer patent document 1 and patent document 2).

The steel pipe used for the pore-polling method is embedded in the ground. Therefore, steel pipes of relatively inexpensive and high strength materials are used. At the time of injecting the injection material, the injection material flowing out through the through hole sufficiently penetrates into the ground and needs to be densely filled in the gap between the ground and the steel pipe. Moreover, in order for the embedded steel pipe to be firmly fixed, it is preferable that the layer of this steel pipe and the injection material of the outer peripheral part is firmly integrated.

However, since the conventional steel pipe is formed as a smooth surface on the outside, there is no jamming with the layer of the external injection material, and both cannot be fixed securely. In order to improve this, there is a method of roughening the surface by sandblasting or the like on the outer surface of the steel pipe. However, this method had its own close contact effect, but has not been satisfied in terms of firmly fixing the steel pipe to the ground.

Further, in Patent Document 3, as a ground reinforcing steel pipe, a spiral convex groove is formed in the outer circumferential portion, and a ground having a plurality of through-holes through which the injection material flows into and out of the steel pipe at a gap portion of the spiral convex groove. Reinforcing steel pipes are disclosed.

Japanese Patent Application Laid-open No. 2000-204870 Japanese Patent Application Laid-Open No. 2001-020657 Japanese Patent Application Publication No. 2006-022501

However, in the steel pipe disclosed by the said patent document 3, since the convex part exists in the outer peripheral surface of a steel pipe, it becomes an obstacle when placing a steel pipe. In addition, this convex portion is obstructed when the soil is discharged from the outer surface side of the steel pipe. Therefore, a convex part cannot be made large and it is difficult to ensure sufficient adhesiveness. Moreover, in order to provide a convex part to the outer peripheral surface of a steel pipe, after manufacturing a steel pipe, the process which provides a convex part by a separate process is needed. Therefore, there exists a problem that productivity falls and cost increases.

The present invention solves the above problems, and without increasing the manufacturing cost, the resistance is small when embedded in the ground, and when the reinforcing material is poured, the ground reinforcing steel pipe and the ground that the steel pipe and its surroundings are firmly adhered firmly and using the same It is aimed at providing the ground reinforcement method and the structure reinforcement method.

MEANS TO SOLVE THE PROBLEM This invention employ | adopts the following means in order to solve the said subject and achieve this objective.

(1) The ground reinforcing steel pipe of the present invention is a ground reinforcing steel pipe which is poured into the ground and injects the injection material into the ground, the recess and the smooth portion disposed on the outer circumferential surface thereof, the recess or the smooth portion. It has a some through-hole through and out of this ground reinforced steel pipe.

(2) The cross-sectional shape of the recessed portion has a depth of the recessed portion of 0.005D to 0.2D and a width of the recessed portion of 0.015D to 2D when the outer diameter of the steel pipe is set to (D). It is preferable that B / H = 3-20 when a shape is triangular shape, and when the width | variety of the said recessed part is (B) and the depth of the said recessed part is (H).

(3) The cross-sectional shape of the concave portion has a depth of the concave portion of 0.005D to 0.2D and a width of the concave portion of 0.015D to 2D when the outer diameter of the steel pipe is (D). It is preferable that B / H = 4-20 when a shape is square shape and the width | variety of the said recessed part is (B), and the depth of the said recessed part is (H).

(4) The cross-sectional shape of the recessed portion has a depth of the recessed portion of 0.005D to 0.2D and a width of the recessed portion of 0.015D to 2D when the outer diameter of the steel pipe is set to (D). It is preferable that B / H = 3-20 when a shape is semi-circle shape or a trapezoid shape, and when the width | variety of the said recessed part is (B) and the depth of the said recessed part is (H).

(5) It is preferable that the said recessed part is formed in multiple numbers on the same circumference of the said steel pipe.

(6) It is preferable that the said recessed part is formed in multiple numbers in the circumferential direction of the said steel pipe, and the said recessed part which opposes at least mutually mutually is formed avoiding the same circumferential image of the said steel pipe.

(7) It is preferable that the said recessed part is formed in multiple in the inclination direction with respect to the axis | shaft of the said steel pipe.

(8) It is preferable that the said recessed part is formed in multiple numbers in parallel with respect to the axis | shaft of the said steel pipe.

(9) It is preferable that the said recessed part is formed in multiple numbers in a circular shape, when the said recessed part is seen from the front.

(10) It is preferable that plating or resin coating is arrange | positioned on the surface of the said steel pipe.

(11) The ground reinforcement method of the present invention, in the case of ground reinforcement, excavates the ground while placing the ground reinforcing steel pipe described in the above (1), and after pouring the ground reinforcing steel pipe, the inside of the ground reinforcing steel pipe The injection material is injected into the outside of the ground reinforcing steel pipe through the plurality of through holes.

(12) It is preferable that the minimum inner diameter of the ground reinforcing steel pipe is larger than the outer diameter of the inner side bit used when digging the ground.

(13) It is preferable that the maximum outer diameter of the said ground reinforcing steel pipe is smaller than the outer diameter of the outer side bit used for excavation of the said ground.

(14) The method of reinforcing the structure of the present invention, after reinforcing the structure including concrete, pours the ground reinforcing steel pipe according to claim 1 while excavating the structure, and after pouring the ground reinforcing steel pipe, the ground Injection material is injected from the inside of the reinforcing steel pipe to the outside of the ground reinforcing steel pipe through the plurality of through holes.

Since the recessed part is formed in the outer peripheral surface of a steel pipe as described in said (1), this recessed part will not become resistance at the time of embedding in the ground. In addition, when the injection material is poured into the outer circumferential surface of the steel pipe, the injection material is filled in the concave portion, and the adhesion to the ground is improved. As a result, the number of embeddings at the time of construction can be reduced, and the construction cost and construction period can be shortened.

In addition, since the steel pipe for ground reinforcement as described in said (1) only forms a recessed part in an outer peripheral surface, it can manufacture, for example, just passing a steel pipe between rolls which have a convex part as it is after piping. Therefore, production efficiency does not fall, and manufacturing cost can also be reduced compared with the conventional method.

Moreover, if the steel pipe for ground reinforcement of said (1) is used, it can apply similarly to reinforcement of structures, such as a concrete foundation of a building, for example, and low cost and firm reinforcement are possible.

1 is a front view showing an example of the ground reinforcing steel pipe of the present invention.
It is a figure which shows an example of the ground reinforcing steel pipe of this invention.
2B is a view showing a modification of the ground reinforcing steel pipe of the present invention.
2C is a view showing a modification of the ground reinforcing steel pipe of the present invention.
2D is a view showing a modification of the ground reinforcing steel pipe of the present invention.
2E is a view showing a modification of the ground reinforcing steel pipe of the present invention.
It is a figure which shows the modification of the ground reinforced steel pipe of this invention.
2G is a view showing a modification of the ground reinforcing steel pipe of the present invention.
It is a figure which shows the modification of the ground reinforced steel pipe of this invention.
It is a figure which shows the modification of the ground reinforced steel pipe of this invention.
It is a figure which shows the modification of the ground reinforced steel pipe of this invention.
It is a figure which shows the modification of the ground reinforced steel pipe of this invention.
It is a figure which shows the specific example of the recessed part of the steel pipe for ground reinforcement of this invention.
It is a figure which shows the specific example of the recessed part of the steel pipe for ground reinforcement of this invention.
It is a figure which shows the specific example of the recessed part of the steel pipe for soil reinforcement of this invention.
3D is a view showing another specific example of the recess of the ground reinforcing steel pipe of the present invention.
It is a figure which shows the relationship between the width | variety and the depth of the recessed part of the steel pipe for soil reinforcement of this invention.
It is a figure which shows the production line of a conventional single welded steel pipe.
Figure 6 is a view showing an embodiment of the production line of the single-piece steel pipe to manufacture the ground pipe reinforcement of the present invention.
It is a conceptual diagram of the roll used for manufacture of the steel pipe of this invention.
It is a conceptual diagram of the roll used for manufacture of the steel pipe of this invention.
8 is a view showing another embodiment of a production line of a single welded steel pipe for producing a ground pipe reinforcing steel of the present invention.
9 is a partial cross-sectional view of the distal end portion of the ground reinforcing steel pipe inserted with a drill rod equipped with a bit.
It is a figure which shows the evaluation method of adhesive force in an Example.
It is a figure which shows the evaluation method of adhesive force in a comparative example.
11 is a diagram comparing effects in the examples.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely by drawing.

In FIG. 1, the ground reinforced steel pipe 5 which concerns on this invention is shown typically. In the ground reinforcing steel pipe 5, the recessed part 2 is formed in the columnar shape at regular intervals in the outer peripheral part of the steel pipe 1. By this recessed part 2, the frictional force of the steel pipe 1, a ground, concrete, etc. can be raised.

In addition, a plurality of through holes 3 passing through the inside and the outside of the steel pipe 1 are disposed on the entire peripheral surface of the steel pipe 1. The injection material injected into the inside of the steel pipe 1 flows out to the outer surface of the steel pipe through these through holes 3. A part of this injection material is filled between the ground and the steel pipe 1, and fixes the ground and the steel pipe 1 to it. In addition, the other part penetrates and solidifies the ground, thereby strengthening the ground. At this time, the recessed part 2 is in the state embedded in the layer of the solidified injection | pouring material, and both are firmly integrated. For this reason, even if an axial force acts on the steel pipe 1, the engagement resistance will be generated by the coupling of the recessed part 2 and the injection material layer, and the movement of the steel pipe 1 will be prevented.

As mentioned above, in the ground material reinforcing steel pipe 5 of this embodiment, the adhesiveness of the steel pipe 1 and the ground is aimed at, and the steel pipe 1 and the ground can be fixed more firmly. In FIG. 1, the code | symbol 4 represents an outer bit.

The manufacturing method of the ground reinforcing steel pipe 5 only gives the recessed part 2 to the surface of the steel pipe 1 by pressing means hot or warm after piping the steel pipe 1 in a steel pipe manufacturing line. . Therefore, productivity is hardly changed with the usual piping process.

2A to 2K show specific examples showing different shapes of the recesses 2.

2A, 2B, and 2C have recesses 2A to 2C in the circumferential direction of a certain steel pipe 1, and a plurality of recesses 2A to 2C are formed at regular intervals in the axial direction. The ground reinforced steel pipe 5 of FIG. 2A is an example in which 2 A of recesses were formed on the same circumference of the steel pipe 1 (two in the figure opposing). The ground reinforcing steel pipe 5 of FIG. 2B forms the recessed part 2 by the reciprocation | compression-type press apparatus which can approach and retract with respect to the steel pipe 1A rather than a rolling roll. The recessed part 2B has almost the same depth on the circumference of the steel pipe 1. In the ground reinforcing steel pipe 5 of FIG. 2C, a plurality of recesses 2C are formed in the circumferential direction of the steel pipe 1, and at least one of the recesses 2C facing each other does not exist on the same circumference. .

Like the steel pipe 1 of FIG. 2C, the position where the recessed parts 2C are arrange | positioned compared with the steel pipe 1 of FIG. 2A by making a zigzag arrangement so that mutually opposing recessed parts 2C may not exist on the same circumference is shown. The strength of the steel pipe 1 can be improved. The steel pipe 1 shown in FIG. 2C is suitable for the case where the strength of the ground reinforcing steel pipe 5, in particular, the strength of the portion where the concave portion 2 is disposed is required to be higher. In the example of zigzag arrangement | positioning of recessed part 2C, it is preferable to form so that the whole width of the opposing part of recessed part 2C may not wrap.

2D to 2G are diagrams showing the steel pipe 1 in which the concave portions 2D to 2G having long sides in the oblique direction with respect to the axis of the steel pipe 1 are formed. 2H and 2I are views showing the steel pipe 1 in which the recesses 2H and 2I having long sides in the direction parallel to the axis of the steel pipe 1 are formed. 2J and 2K are diagrams showing the steel pipe 1 in which the recesses 2J and 2K having a rounded spot shape (circular shape) are formed. The spot-shaped recesses 2J and 2K can be freely selected from ellipses, polygons and the like from the ease of formation. In addition, it is also possible to freely select whether the recesses 2D to 2G are arranged on the same circumference or alternately arranged in a zigzag shape.

Here, the restriction of the shape of the recesses 2D to 2G is only a height, and it is sufficient to secure a space enough for the excavation beads to pass through the inner surface of the steel pipe 1.

The ground reinforced steel pipe 5 of this invention forms the recessed part 2 hot or warm as mentioned later. Therefore, even if the thickness of the steel pipe 1 is 2 mm or more, it can manufacture easily, for example. Therefore, when a thick ground reinforcing steel pipe 5 is manufactured and the ground reinforcing steel pipe 5 is embedded while being rotated in the ground, for example, a torsional force acts on the ground reinforcing steel pipe 5, resulting in bending. The tip is not crushed. Moreover, the thing with the outer diameter of 50 mm or more which can be practical as the steel pipe 5 for ground reinforcement can be manufactured easily.

When using the steel pipe 5 for ground reinforcement which concerns on this invention especially for the use for which corrosion resistance is calculated | required, plating or resin coating is applied to the surface of the steel pipe 1 which comprised the recessed part 2 as mentioned above. It is preferable to implement and to exhibit favorable corrosion resistance.

As for the recessed part 2 of the steel pipe 1, as shown to FIG. 3A-FIG. 3D, the case where a cross-sectional shape is a triangular shape and the case where a cross-sectional square shape is basically possible can be considered. In the case of a semicircle shape and a trapezoidal shape, you may think that it is substantially equivalent to a triangle. In any case, the depth (representing the depth of the deepest portion) H of the concave portion 2 is 0.005 × D in order to obtain frictional force between the peripheral surface of the steel pipe 1 and the ground or concrete. : Steel pipe outer diameter) However, since the effect of a frictional force improvement also becomes saturated above 0.2xD, the depth H of the recessed part 2 shall be 0.005xD-0.2xD. In addition, in order to obtain the said frictional force, the width | variety B of the recessed part 2 requires 0.015 * D or more. However, in more than 2xD, since the frictional force improvement effect is small, it is necessary to be 2xD or less.

Moreover, it is important to prescribe the following matters from the viewpoint of optimizing the shape of the recessed part 2 based on the said premise. That is, when the cross-sectional shape of the recessed part 2 is triangular shape, B / H = 3-20. When the cross-sectional shape of the recessed part 2 is rectangular shape, B / H = 4-20. When the cross-sectional shape of the recessed part 2 is a semicircle shape or a trapezoid shape, B / H = 3-20.

Hereinafter, the process from which the above-mentioned B / H relationship was derived is demonstrated using FIG. As a premise, the failure mode in the concave portion 2 is determined by the shear strength of the soil cement at the outer side of the concave portion, that is, at the bottom of the triangle (the width B of the concave portion 2) in FIG. 4. , Shall be determined by any one of the bearing strength of the soil cement in the recess 2. At this time, if any one of the breakdown modes is apparently preceded by the other, the strength is determined by the breakdown mode, so the strength is considered to be lowered. Therefore, in consideration of the optimum shape of the concave portion 2, it is necessary to find a shape in which the two failure modes described above occur simultaneously.

As a result, in the optimum shape of the concave portion 2, it is required that the bearing pressure P imparting the acupressure strength and the shear force S imparting the shear strength satisfy the equilibrium conditional expression of the following [Equation 1]. do.

[Equation 1]

S = Pcosθ

Is the angle formed between the surface of the steel pipe 1 and the inlet side of the recess 2.

Here, the shear force S is defined as the area x shear force on which the shear force acts. Therefore, the shear force S is formulated by the following [formula 2]. Here, it is assumed that the recesses 2 are disposed around the entire circumference of the steel pipe 1. The shear area is represented by the product of the circumferential length πD of the steel pipe 1 and the width B of the concave portion 2 (the base of the triangle).

[Equation 2]

S = τ, B, π, D

On the other hand, the bearing pressure P is multiplied by the area acting on the bearing stress, and is formulated by the following [formula 3].

[Equation 3]

P = H · σb · cosθ · π · D

τ: shear stress, D: outer diameter of steel pipe, σb: bearing pressure (pressure stress, force / area dimension) Substituting [Equation 2] and [Equation 3] into [Equation 1], the following [Equation 4] , [Equation 4 '] is derived.

[Equation 4]

τ · B = (H · σb · cosθ) cosθ

[Equation 4 ']

∴ B / H = σb · cos ² θ / τ

[Equation 4 '] is a modification of the equilibrium condition equation [Equation 1] of the force at the time of providing the optimum shape. Here, when the angle (theta) which the side surface of the recessed part 2, ie, the inclined surface of the triangle of FIG. 4, and the surface of the steel pipe 1 forms is 45 degree | times (this is hereafter referred to as a triangular shape), and 90 degree | times, It shall be solved about (hereinafter, it shall be set as square shape).

When θ = 90 ° [the concave portion 2 has a square shape],

[Equation 5]

B / H = σb / τ

Becomes For example, substituting acupressure strength (σb) = 1 N / mm 2 and shear strength (τ) = 0.1 N / mm 2 of small cement into [Equation 5], B / H = 10 [width of concave portion 2] 10 times this height], and the shape of the recessed part 2 becomes a rectangle with a long side 10H and a height H. FIG.

On the other hand, if the shape of the final concave portion 2 is a triangular shape and the triangle is an isosceles triangle, the following relational expression (Equation 6) is established in B, H, and θ.

[Equation 6]

tanθ = 2 · H / B

Substituting this into [Equation 4 '],

[Equation 7]

2 / (sinθcosθ) = σb / τ

Becomes Substituting the pressure strength (σb) = 1 N / mm 2 and shear strength (τ) = 0.1 N / mm 2 of the small cement into this [Formula 7],

[Equation 8]

sinθ · cosθ = 1/5

[Equation 8 ']

sin2θ = 2/5 = 0.4

∴θ = 11.8

Becomes

The relationship between acupressure strength (σb) and shear strength (τ) of soil cement (concrete)

When 1 / 20≤τ / σb≤2 / 9 (typically, τ / σb = 1/10),

(a) In the case where the shape of the concave portion 2 is a quadrangle, the relationship between the width B and the depth H of the concave portion 2 is expressed by Equation 5,

4.5≤B / H≤20.0

(b) In the case where the shape of the concave portion 2 is a triangular shape, an appropriate range of θ is expressed by [Equation 7].

5.8≤θ≤31.4

At this time, the relationship between the width B and the depth H of the concave portion 2 is expressed by [Expression 6].

3.3≤B / H≤19.8

Becomes

Here, also in the case of the inclined, parallel, or spot-shaped recesses 2 in the axial direction of the steel pipe 1 as shown in Figs. 2D to 2K, the AA cross section in Fig. 2D, the HH cross section in Fig. 2H, What is necessary is just to apply the said formula to the CC cross section of FIG. 2J.

In view of the above, in the present invention, B / H is defined as follows.

(1) When the cross-sectional shape of the concave portion 2 is triangular, B / H = 3 to 20

(2) When the cross-sectional shape of the recessed part 2 is square shape, B / H = 4-20

(3) When the cross-sectional shape of the concave portion 2 is a semicircle shape or a trapezoidal shape, B / H = 3 to 20

Next, the manufacturing method of the ground reinforced steel pipe 5 which concerns on this invention is demonstrated.

In the present invention, any of the following steps a), b), c) and d) can be applied, but the present invention will be described using a production line of a single welded steel pipe as a representative example.

a) In an electroplating steel pipe manufacturing line, after electroplating welding, this steel pipe is heated and the surface is pressed by a pressing means.

b) In the hot or warm welded steel pipe production line, after welding, the surface is pressed by the pressing means.

c) In a single-piece steel pipe manufacturing line, after the welding, the surface is pressed by the pressing means.

d) In the seamless steel pipe production line, after the pipe is pressed, the surface is pressed by the pressing means.

It is a figure which shows the production line of a normal single weld pipe.

The steel strip 10 slit to a desired width is shape | molded by the roll 21 to circular shape of cross section. Thereafter, both ends of the roll 22 are heated at high temperatures, press-bonded, and fused together. The joined tube is narrowed by the subsequent rolls 23 to 34 to shrink in diameter to a predetermined dimension. And it cut | disconnects to predetermined length with the cutter 38, the shape is aligned with the subsequent rolls 35-37, and the single welded pipe 11 (steel pipe 1) is manufactured.

6 is one embodiment of a single-tube production line.

In the conventional manufacturing line, only the final roll 34 of the squeeze roll in front of the cutter 38 is changed. As shown in FIGS. 7A and 7B, the rolls 34 are provided with convex portions α at one or a plurality of positions in the axial direction of the roll 34. This convex part (alpha) is used as a press means. The roll 34 in which this convex part (alpha) was provided is used for both up and down or one side. In FIG. 6 and FIG. 7A-FIG. 7B, although it shows with the upper and lower rolls 34a and 34b, one set may be three or more rolls. By the roll 34 which has such convex part (alpha), the pressure is applied to the high temperature (about 1200-1300 degreeC) short junction pipe 11. Therefore, the recessed part 2 is easily formed in the part of the single joint pipe 11 which the convex part (alpha) touches. In addition, the shape of the recessed part 2 is formed in the shape based on the shape of the convex part (alpha) of the roll 34 compared with the process by cold. Therefore, a more sharp recess 2 is obtained. Thereafter, the ground reinforcing steel pipe 5 of the present invention, which is cut into a predetermined length and shaped, and has a recessed portion 11a, is completed.

Here, in the case where the height, width, and pitch of the concave portion 2 on the single weld pipe 11 are to be changed, the shape and pitch of the convex portion α of the roll 34 may be changed. In addition, when the convex part (alpha) is provided in both the upper and lower rolls 34a and 34b, and the position of the recessed part 2 on the single joint pipe 11 is to be formed in the same position, the upper and lower rolls 34a and 34b The position of the convex part (alpha) of 1 may be made into the initial stage, for example, the upper and lower rolls 34a and 34b may be connected through one drive source, a universal joint, etc., and it may synchronize and drive the upper and lower rolls 34a and 34b. .

It is preferable to make the shape of the convex part (alpha) formed in the roll 34 as high as the center part of the roll 34, and toward the edge part of the roll 34, as shown in FIG. 7B. At the center part and the edge part of the roll 34, a circumferential speed is different. For this reason, the peripheral speed is larger at the end of the larger diameter. Therefore, since the rotation of the roll 34 advances faster than the tube which passes, unnecessary force is applied to the single weld pipe 11. As a result, more than necessary deformation | transformation and distortion are provided to the single joint pipe 11.

8 is an example of another short pipe production line.

In this example, it is an example which provided the pressurization apparatus (pressing means) 39 to the exclusive single welded pipe 11 (steel pipe 1) between the squeeze roll 34 and the cutter 38. As shown in FIG. As the pressurization apparatus 39, the roll 34 which has the above-mentioned convex part (alpha) may be sufficient, and the thing of the type which presses on the single weld pipe 11 in the form of being pinched from top and bottom may be sufficient. And it is preferable that this pressurization apparatus 39 has the mechanism which can advance and retreat with respect to the end weld pipe 11 or advancing and advancing in the advancing direction of the end weld pipe 11.

Since the pressurization apparatus 39 can approach and retract with respect to the single welded pipe 11, the recessed part 2 can be formed in the arbitrary position of the single welded pipe 11. As shown in FIG. In addition, even when it is going to change the pitch of the recessed part 2, it is not necessary to replace | exchange the roll 34. Moreover, by this function, the control part recognizes the cutting position of the short weld pipe 11 beforehand, and it becomes possible to control so that the recessed part 2 may not be located in this cutting position. When the recessed part 2 comes to the edge part of the short weld pipe 11, the diameter and shape of an end surface will become different for every short weld pipe 11. As shown in FIG. In this case, for example, connection of the single welded pipes 11 becomes difficult.

Moreover, by making the pressurizing device 39 moveable in the advancing direction of the single welded pipe 11, it can move with the advancing of the single welded pipe 11, and can move the formation apparatus of a diameter reduction part. Thereby, unnecessary distortion etc. to the single joint pipe 11 by the difference of the peripheral speed of the center part and the edge part of the roll 34 mentioned above do not generate | occur | produce, and the shape of the recessed part 2 can be formed freely.

As mentioned above, although demonstrated in the exclusive apparatus, you may have these functions in the roll 34 which provided the convex part (alpha) in the existing final squeeze roll.

As described above, the tubing method may be any one of a tubing method by an electric rod, a tubing method by welding hot or warm, a tubing method by a single joint, and a seamless tube method. Heating or the like in the tube or after the tube can be performed by pressing means to press the surface of the tube in a warm or hot state, whereby the steel tube 1 with the concave portion 2 formed online can be manufactured.

And since the recessed part 2 is formed hot in the steel pipe 1 manufactured by these manufacturing methods, even if the thickness of the steel pipe 1 is 2 mm or more, it can be manufactured easily. For example, when the steel pipe 1 is thick while being embedded in the ground as a steel pipe pile, a torsion force acts on the steel pipe 1 so that the steel pipe 1 is not bent or the tip end is crushed. . In addition, the steel pipe 5 for ground reinforcement can also be easily manufactured having a practical outer diameter of 50 mm or more. Moreover, production efficiency is the same as when manufacturing a normal single welded steel pipe.

By the manufacturing method of a steel pipe as mentioned above, in the manufacturing line of a normal steel pipe, the concave part 2 can be provided continuously at the same time as steel pipe manufacture by producing into a dedicated roll which provided the processus | protrusion. In addition, by changing the shape of the projection α of the exclusive roll 34, the recess 2 of a free shape, spacing, and arrangement can be arbitrarily provided. In addition, since there is no need for processing by a separate process, it is possible to provide the steel pipe 1 in which the recesses 2 are formed at a very low cost.

In the ground reinforcing steel pipe 5 of the present invention, the convex shape (that is, the concave portion 2) is provided on the inner surface side instead of the outer surface side of the steel pipe 1 in this way, so that the steel pipe 1 is placed. At the time, this recessed part 2 does not interfere. Moreover, the steel pipe 5 for ground reinforcement which has the large recessed part 2 which can ensure sufficient adhesiveness can be manufactured at low cost, without reducing productivity.

Then, the plurality of through holes 3 are drilled in the steel pipe 1 in which the recesses 2 are formed. The through hole 3 may be a recess 2 on the circumference of the steel pipe 1 or may be formed in a smooth portion other than the recess 2. Alternatively, it may be formed on either side. The diameter and arrangement of the through hole 3 may be evenly distributed to every corner over the entire length, and may be arbitrarily determined according to the properties of the reinforcing agent to be injected and the state of the ground to be injected.

9 shows the positions of the excavation bits 4, 7 and the ground reinforcing steel pipe 5. The outer side bit 4 excavates the ground and the like while rotating by the power transmitted from the rod 6 and the inner side bit 7. Behind the outer bit 4, the ground reinforcing steel pipe 5 of the present invention is disposed. Therefore, the outer diameter of the ground reinforcing steel pipe 5 may be smaller than the outer diameter of the outer side bit 4.

In addition, the rod 6 and the inner bit 7 pass through the inside of the ground reinforcing steel pipe 5. Therefore, it is necessary to make the minimum inner diameter of the steel pipe 1 larger than the maximum outer diameter of the inner side bit 7. As long as the above conditions are satisfied, the depth of the recessed part 2 on one round of steel pipes can be taken large.

When using this ground reinforcing steel pipe 5, as shown in FIG. 9, the drill rod 6 which attached the inner side bit 7 to the front end part is inserted through this steel pipe 1, and the inner side of the front end part is inserted. The bit 7 protrudes from the outer bit 4 of the steel pipe 1, and the rear end of the drill rod 6 and the steel pipe 1 is connected to a rock drill (not shown). Then, the drill rod 6 and the steel pipe 1 are drilled while giving blow, rotation and thrust from the rock drill. During drilling, water or compressed air is supplied from the rock drill and discharged from the tip end of the outer bit 4. Slimes generated by the perforation are mostly discharged through the inside of the steel pipe 1, but some are discharged backward through the outside of the steel pipe 1.

When the drilling of the predetermined depth is completed and the steel pipe 1 is embedded in the ground, the drill rod 6 together with the inner bit 7 is pulled backward from the steel pipe 1. Thereafter, an injection device (not shown) is attached to the rear end of the steel pipe 1 to press the injection material into the steel pipe 1. This injection | pouring material fills up in the steel pipe 1, and flows out through the many through-holes 3 formed in this steel pipe 1 to the outside. And while it flows along the outer surface of the steel pipe 1, it penetrates and solidifies in the ground. This strengthens the ground.

Since the recessed part 2 is formed in the outer peripheral part of this steel pipe 1, this recessed part 2 will be in the state embedded in the layer of the injection material which solidified, and both are firmly integrated. For this reason, even if an axial force acts on the steel pipe 1, the engagement resistance will be generated by the coupling of the recessed part 2 and the injection material layer, and the movement of the steel pipe 1 will be prevented. In this way, the steel pipe 1 is firmly fixed in the ground. Since the concave portion 2 has a predetermined cross-sectional shape, it is possible to simultaneously improve the fluidity of the injection material or the slime and the locking resistance for preventing deviation.

The said recessed part 2 is normally formed of a rolling roll. Therefore, the cross-sectional shape becomes a smooth shape without an edge part or a corner part. Therefore, the slime or the injection material flows smoothly, and no clogging or voiding occurs partially. As a result, not only the discharge state of the slime is good, but also the adhesion between the injection material and the steel pipe 1 is improved, and excellent ground reinforcement can be achieved. In the above description, a combination of a ring-shaped outer bit 4 fixed to the distal end of the steel pipe 1 and an inner bit 7 mounted to the distal end of the drill rod 6 is employed as the bit, but the aperture is expanded. By using the retractable expansion and contracting bits, the drilling may be performed by expanding the aperture so as to be larger than the outer diameter of the steel pipe 1 at the time of drilling, and shrinking the aperture so as to be smaller than the inner diameter of the steel pipe 1 at the end of the drilling. . In this case, it is not necessary to fix the ring bit (outer bit) 4 to the distal end of the steel pipe 1.

Example

Next, since the adhesive force was compared on the following levels, it demonstrates. The level was made into three levels of Table 1. Size: 76.3mmφ × 3.2mmt × 6mL, standard STK

10A and 10B, the evaluation method of the adhesive force embedded the steel pipe 5 for ground reinforcement in the soil cement 100, applied the load from the upper part 101, and measured the maximum load (maximum load). Adhesion was evaluated). FIG. 10: A is a figure which shows typically the evaluation method at the time of embedding the ground reinforced steel pipe 5 of this invention. FIG. 10: B is a figure which shows typically the evaluation method at the time of embedding the steel pipe 102 in which the convex part 103 was arrange | positioned as a 2nd comparative example.

As the soil cement 100, a mixture of soil and a hardener was used. At this time, the soil was carried out in two cases of clay and sandy soil. The particle diameter of the clay is 0.001 to 0.005 mm, and the particle diameter of the sandy soil is 0.074 to 2.000 mm. As a result, as shown in Fig. 11, the present invention was confirmed that the punching load is large, that is, the adhesion is large compared with other comparative examples.

The manufacturing cost of the ground reinforced steel pipe in which the recessed part of this invention was formed is about the same as the manufacturing cost of the straight pipe of a 1st comparative example. On the other hand, in the convex part forming steel pipe of a 2nd comparative example, the cost of the additional welding for forming a convex part is added to piping cost. Therefore, it becomes expensive. Thus, it turns out that this invention is excellent also in cost.

As apparent from the above description, the ground reinforcing steel pipe according to the present invention has a recess formed on the outer circumferential surface of a conventional steel pipe, and can effectively perform ground reinforcement in tunnel construction or a structure such as a concrete foundation at low cost. have.

1: steel pipe
2 recess
3: through-hole
4: outside bit
5: ground reinforcement steel pipe

Claims (14)

It is poured on the ground, and it is a steel pipe for ground reinforcement for injecting the injection material into the ground,
Recesses and smooth portions disposed on the outer circumferential surface thereof,
The ground reinforcing steel pipe, characterized in that the concave portion or the smooth portion has a plurality of through holes that pass through the ground reinforcing steel pipe. The cross-sectional shape of the concave portion according to claim 1, wherein the depth of the concave portion is 0.005D to 0.2D and the width of the concave portion is 0.015D to 2D when the outer diameter of the steel pipe is (D).
When the cross-sectional shape of the recess is triangular, and the width of the recess is (B) and the depth of the recess is (H),
B / H = 3 to 20, characterized in that the steel pipe for ground reinforcement. The cross-sectional shape of the concave portion according to claim 1, wherein the depth of the concave portion is 0.005D to 0.2D and the width of the concave portion is 0.015D to 2D when the outer diameter of the steel pipe is (D).
The cross-sectional shape of the said recessed part is square shape, B / H = 4-20 when the width | variety of the said recessed part is set to (B), and the depth of the said recessed part is set to (H), The ground reinforcement steel pipe characterized by the above-mentioned. The cross-sectional shape of the concave portion according to claim 1, wherein the depth of the concave portion is 0.005D to 0.2D and the width of the concave portion is 0.015D to 2D when the outer diameter of the steel pipe is (D).
The cross-sectional shape of the concave portion is semicircular or trapezoidal, and when the width of the concave portion is set to (B) and the depth of the concave portion is set to (H), the ground reinforcement is characterized in that B / H is 3 to 20. Dragon steel pipe. The steel pipe for ground reinforcement according to claim 1, wherein a plurality of the recesses are formed on the same circumference of the steel pipe. The said recessed part is formed in multiple numbers in the circumferential direction of the said steel pipe,
The steel pipe for ground reinforcement which at least the said recessed part opposing each other is formed avoiding the same columnar shape of the said steel pipe. The steel pipe for ground reinforcement according to claim 1, wherein a plurality of the recesses are formed in an inclined direction with respect to the axis of the steel pipe. The steel pipe for ground reinforcement according to claim 1, wherein a plurality of the recesses are formed in parallel with the axis of the steel pipe. The steel pipe for ground reinforcement according to claim 1, wherein a plurality of the recesses are formed in a circular shape when the recesses are viewed from the front. The steel pipe for ground reinforcement according to claim 1, wherein plating or resin coating is arranged on the surface of the steel pipe. In the case of ground reinforcement, while laying the ground, the steel pipe for ground reinforcement of Claim 1 is poured,
And after pouring the ground reinforcing steel pipe, an injection material is injected from the inside of the ground reinforcing steel pipe to the outside of the ground reinforcing steel pipe through the plurality of through holes. The ground strengthening method according to claim 11, wherein the minimum inner diameter of the ground reinforcing steel pipe is larger than the outer diameter of the inner bit used when digging the ground. The ground strengthening method according to claim 11, wherein the maximum outer diameter of the ground reinforcing steel pipe is smaller than the outer diameter of the outer bit used for excavation of the ground. At the time of reinforcement of the structure including concrete, the ground reinforcing steel pipe according to claim 1 is poured while excavating the structure,
And after pouring the ground reinforcing steel pipe, an injection material is injected from the inside of the ground reinforcing steel pipe to the outside of the ground reinforcing steel pipe through the plurality of through holes.

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