JP2005282174A - Steel pipe sheet pile joint, steel pipe sheet pile joint structure and steel pipe sheet pile foundation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the accuracy of embedding a steel pipe sheet pile and to have good workability regarding excavation, washing and mortar filling of the earth and sand of the joint part, and to reliably improve the joint shear strength in the pipe axis direction and to increase the axial force in the cross section. To provide a steel pipe sheet pile joint that can resist, a steel pipe sheet pile joint structure, and a steel pipe sheet pile foundation.
SOLUTION: A pair of L-shaped steel materials 10 are arranged at a predetermined interval in the axial direction of the outer surface of a steel pipe sheet pile main pipe 3, and an arm portion 11 of each L-shaped steel material 10 is disposed inward, and each L-shaped steel material 10 A female joint 13 to which the legs 12 are fixed and a pair of L-shaped steel materials 14 are arranged in the outer surface axial direction of the steel pipe sheet pile main pipe 3 with a predetermined interval, and the arm portions 15 of each L-shaped steel material 14 are arranged outward. In addition, in the steel pipe sheet pile joint connected by the male joint 17 to which the leg portion 16 of each L-shaped steel material 14 is fixed, the outer peripheral surface of the main pipe sandwiched between the L-shaped steel materials in the female joint and the male joint In addition, a plurality of rod-shaped steel materials with projections are arranged in the outer circumferential direction of the steel pipe at intervals of three times the diameter of the rod-shaped steel materials with projections, and are arranged and fixed so as to extend in the axial direction of the main pipe. .
[Selection] Figure 1

Description

  The present invention relates to a steel pipe sheet pile joint, a joint structure of steel pipe sheet piles and a steel pipe sheet pile foundation for connecting and merging steel pipe sheet piles such as a steel pipe sheet pile foundation and a retaining structure.

  Conventionally, as shown in FIG. 9 and FIGS. 12 to 13, a steel pipe sheet pile structure or a steel pipe sheet pile foundation 2 constructed by connecting and merging a plurality of steel pipe sheet piles 1 connects the steel pipe sheet pile main pipes 3 to each other. In addition, as shown in FIG. 8A, a circular joint steel pipe 4 having a slit 6 is generally used. Then, the steel pipe sheet piles 1 are continuously built in the ground by fitting the joint steel pipes 4 to each other, and after excavating and cleaning the earth and sand in the joint steel pipe 4, the mortar 5 is filled in the joint steel pipe 4 and constructed. To do.

In general, the joint steel pipe 4 used for the PP joint is one having an outer diameter of 165.2 mm and a plate thickness of 11 mm and having no irregularities such as protrusions on the inner surface. Moreover, as the mortar 5 to be filled, those having a compressive strength of about 20 N / mm ² are used.

  The joint used for the steel pipe sheet pile 1 is P (pipe) -P (pipe) that fits joint steel pipes (P: pipes) 4 having slits 6 as shown in FIGS. 8, 9, and 12 to 13. ) In addition to the joint portion 8a (8), as shown in FIG. 8B, a female joint 4a made of a joint steel pipe (P: pipe) 4 having a slit 6 in the axial direction and a T-shaped male joint made of T-shaped steel 4b PT joint portion 8b (8) by meshing with each other, or as shown in FIG. 8 (c), two female joints 4a and one piece of L-shaped steel installed in parallel and spaced apart from each other In some cases, an L-T joint portion 8c (8) formed by meshing male joints 4b made of T-shaped steel is used.

  However, in the steel pipe sheet pile foundation 2, the reason why the PP joint is normally used is as follows. (1) In the case of the steel pipe sheet pile foundation 2, the joint steel pipe 4 In the fitted state, it becomes a three-chamber structure shown by A, B, and C in FIG. 9 and a PP joint with a certain waterproof property is suitable. (2) In the design method of the steel pipe sheet pile foundation 2, P This is because the design method is intended only for the -P joint.

  By the way, when a horizontal external force acts on the steel pipe sheet pile foundation 2, a shearing force acts on the pipe axis direction of the joint steel pipe 4 of the steel pipe sheet pile 1. In this case, when the shear strength of the joint portion 8 is small, the joint portion is displaced in the axial direction. Therefore, the bending rigidity of the entire structure of the steel pipe sheet pile foundation 2 is defined by the shear strength of the joint portion 8. From this, in order to improve the bending rigidity of the steel pipe sheet pile foundation 2, it is effective to improve the shear strength in the pipe axis direction of the joint portion 8.

  As a method of increasing the shear strength of joints for PP joints, an experimental study of high strength joints in steel pipe sheet pile foundations (Katayama et al .: 49th Annual Scientific Lecture, Japan Society of Civil Engineers, April 1994) ( Non-Patent Document 1), or “JP 2000-220135 A (connection structure of steel pipe sheet pile and steel pipe sheet pile)”, Patent Document 1 ”, or“ JP 2000-355931 A (connection structure of steel pipe sheet pile) ”Patent Document 2. Etc.].

  The above three documents all have a structure using a steel pipe with an inner surface protrusion as a joint steel pipe, and it is pointed out that the joint shear strength increases as the steel pipe diameter increases and the filling mortar strength increases. Moreover, in order to suppress the shear fracture of the joint steel pipe, the invention relates to a joint structure in which a reinforcing member is arranged.

  However, in the case of a PP joint, since the fitting joint portion 8a (8) in which the joints are fitted to each other is formed by three chambers A, B, and C, the joint portion 8a ( 8) In order to excavate and clean the soil and fill the mortar 5, the construction is performed in the narrow sections A, B, and C of the joint portion 8a (8), so that the mortar is reliably cleaned and densely filled. This is difficult, and the quality may become unstable. Therefore, there is a possibility that a predetermined joint shear strength cannot be surely exhibited.

  Further, as a method of increasing the joint shear strength for the PT joint portion 8b (8) and the LT joint portion 8c (8) as shown in FIGS. There is a technique published by Kaihei 8-27774 (Patent Document 3) or JP-A-11-140863 (Patent Document 4).

  Japanese Patent Laid-Open No. 8-27774 (fitting joint member and fitting joint portion structure) (Patent Document 3) describes a male fitting joint having a protrusion on the fitting surface of a male and female fitting joint and a reinforcement on the outer peripheral surface. This is a joint structure with a female fitting joint provided with a protrusion for use.

  "Japanese Patent Laid-Open No. 11-140863 (Joint member of steel pipe sheet pile, joint structure, and steel pipe sheet pile foundation using them)" (Patent Document 4) is a male-female fitting joint provided with a protrusion on the surface of the steel pipe. It is a joint structure which is configured by a combination of an L-type joint and a T-type joint or an H-type joint, and further has a plate-like member having protrusions on the surface of the steel pipe.

  These also have a small joint fitting space, so it is difficult to perform reliable cleaning and solid mortar filling, and the quality may become unstable. Even in a joint, it is difficult to reliably exhibit a predetermined joint shear strength. In addition, in order to provide a plate-like member on the surface of the steel pipe, it is necessary to bend the plate-like member according to the curvature of the steel pipe and then perform welding, which not only complicates the processing but also reduces the processing cost. Therefore, the steel pipe sheet pile becomes expensive, which increases the construction cost of the steel pipe sheet pile foundation.

  By the way, as shown in FIGS. 12-13, in the temporary cut-off part 7 of the steel pipe sheet pile foundation 2 and the excavation part of the earth retaining wall, water pressure and earth pressure act from the exterior of a well structure. However, the conventional joint structure as described above cannot resist the in-plane axial force (force in the circumferential direction of the cylinder) and the out-of-plane cross-sectional force (bending force). 9b and supporting works (not shown) for supporting them need to be arranged. In construction, it is a problem that the construction cost increases due to the arrangement of the cut beam 9a, the abdomen 9b, and the supporting work for supporting them, and a long construction period is required.

For the purpose of resisting the axial force in the joint (circumferential compressive force), “Japanese Patent Laid-Open No. 54-154112” (Patent Document 5) has a male and female joint fitted and arranged in concrete. A method for constructing earth retaining walls filled with selenium is described. However, the technique described in this publication describes that a concrete constraining piece is attached to the circumferential surface of a steel pipe sheet pile mainly for the purpose of resisting axial force (circumferential compressive force) acting on the joint. However, there is no description or suggestion regarding improvement of joint shear strength.
Moreover, the description about the shape state and surface state of the concrete member of a concrete restraint piece is not carried out, either. Further, in this case, since the interval holding member is installed at the center of the joint space, there is a problem that the joint inner space is divided into two parts, and cleaning of the joint fitting space becomes complicated.

  Further, in Japanese Patent Publication No. 49-022404 (Patent Document 6), different diameter steel bars are welded along the axial direction to the outer peripheral surface of the steel pipe in the joint gap for the purpose of increasing the shear strength of the joint. Steel pipe sheet pile joints are described. In this publication, an L-shaped steel (an angle steel) is used as a joint, and a joint (LL joint) having a relatively large joint space is described. However, a joint using an L-shaped steel has a fitting margin. Due to its large size, it is difficult to ensure the accuracy of steel pipe sheet pile installation, and the mating space may be reduced depending on the mating condition. It becomes. In addition, depending on the arrangement method of the different diameter steel bars, the shear failure mode of the joint portion is different, and the adhesion strength between the different diameter steel bars and the filler cannot be sufficiently exhibited.

The conventional high strength joint structure with the application of PP joint, PT joint and LT joint has a narrow fitting space, and the inside of the fitting space is reliably washed and filled with mortar. Since it is difficult to perform and the quality becomes unstable, it is difficult to reliably exhibit a predetermined joint shear strength. Moreover, in the high strength joint structure by the application of the conventional LL joint, it is difficult to ensure the steel pipe sheet pile erection accuracy and excavation / cleaning workability in the joint, and the predetermined joint shear strength can be ensured. Can not be demonstrated. Moreover, since it cannot resist the axial force in the cross section of a steel pipe sheet pile foundation, it has the subject which requires many cutting beams and support work.
JP 2000-220135 A JP 2000-355931 A JP-A-8-27774 Japanese Patent Laid-Open No. 11-140863 JP 54-154112 A Japanese Patent Publication No.49-022404 Steel pipe sheet pile foundation design and construction manual (p.14) issued by the Japan Road Association (1997 edition)

As described above, the conventional joint structure (1) ensures the accuracy of steel pipe sheet pile installation, (2) excels in excavation, cleaning and mortar filling of the joint, (3) pipe shaft There is a problem that the three problems of reliably improving the joint shear strength in the direction cannot be satisfied at the same time.
Then, an object of this invention is to provide the steel pipe sheet pile joint which can satisfy these three subjects simultaneously, the joint structure of a steel pipe sheet pile, and the steel pipe sheet pile foundation.

In order to advantageously solve the above-described problems, the present invention is configured as follows.
In the steel pipe sheet pile joint of the first invention, a pair of L-shaped steel materials are arranged at a predetermined interval in the outer surface axial direction of the steel pipe sheet pile main body, and the arm portions of the respective L-shaped steel materials are arranged inwardly, and each L-shaped steel material. And a pair of L-shaped steel members at a predetermined interval in the axial direction of the outer surface of the steel pipe sheet pile main body and arm portions of the respective L-shaped steel materials are arranged outwardly and In a steel pipe sheet pile joint connected by a male joint to which a leg portion of the shaped steel material is fixed, a plurality of protruding rods are formed on the outer peripheral surface of the main pipe sandwiched between the female joint and each L-shaped steel material in the male joint. The steel material is disposed and fixed so as to extend in the main shaft axis direction while being disposed in the outer periphery direction of the main tube with an interval of three times or more the diameter of the rod-shaped steel material with protrusions.
Moreover, in the 2nd invention, in the steel pipe sheet pile joint of the 1st invention, the leg part length of the L-shaped steel material forming the pair of female joints has a length necessary to ensure the erection accuracy of the steel pipe sheet pile, And the leg part length of L-shaped steel material which forms a pair of male type | mold joint has length required in order to ensure the earth and sand excavation in a joint, and the injection | pouring operation | work of a filler.
Further, in the third invention, in the steel pipe sheet pile joint of the first invention, the leg portion length of the L-shaped steel material forming the pair of male joints has a length necessary for ensuring the accuracy of embedding the steel pipe sheet pile, And the leg part length of L-shaped steel material which forms a pair of female type | mold joint has length required in order to ensure the earth and sand excavation in a joint, and the injection | pouring operation | work of a filler.
Moreover, in the 4th invention, in the steel pipe sheet pile joint in any one of the 1st invention-the 3rd invention, it has a processus | protrusion on the surface which a pair of said L-shaped steel material opposes.
Moreover, in the joint structure of the steel pipe sheet pile foundation of the fifth invention, in the joint structure of the steel pipe sheet pile foundation using the steel pipe sheet pile joint of any of the first to fourth inventions, a space surrounded by the steel pipe sheet pile main pipe and the joint member The interior is filled with a cement-based filler.
Moreover, in the steel pipe sheet pile foundation of the 6th invention, in the steel pipe sheet pile foundation formed by connecting and closing a plurality of steel pipe sheet piles, the steel pipe sheet pile using any one of the joints of the first invention to the fourth invention is formed into a cylindrical shape. It is characterized by being closed.

Protruding rod-shaped steel materials are arranged at appropriate intervals (more than 3 times the diameter of the protruding rod-shaped steel materials), so that the adhesion strength with mortar can be reliably exerted, and excellent shear strength is ensured. It can be set as the joint and joint structure which can be exhibited.
The length of the leg part of the L-shaped steel material is a joint part that is appropriately set so as to ensure the accuracy of construction, so that the joint part has an appropriate fitting margin. It can be used as a time guide, and the steel pipe sheet pile can be built with high accuracy.
Since there is sufficient space for soil excavation cleaning in the fitting joint and filling work of cement-based room temperature curable materials such as mortar, the earth and sand in the fitting joint can be reliably excavated, and The fitting joint can be reliably cleaned, and the fitting joint can be filled with cement-type room temperature curable materials such as mortar, and the workability of these fittings has been dramatically improved. In addition, the steel pipe sheet pile main pipe is provided with a plurality of protruding bar-like steel materials, ensuring reliable adhesion to the cement-based room temperature curable material that is filled and hardened in the fitting joint. Thus, it is possible to obtain a joint and joint structure that can improve the rigidity of the joint part, particularly the joint shear strength in the tube axis direction.
By improving the joint shear strength in the pipe axis direction, the overall bending rigidity of the steel pipe sheet pile foundation is increased. Therefore, the overall dimensions of the steel pipe sheet pile foundation can be reduced and the construction cost can be greatly reduced. .
L-shaped steel joints and bar steel with protrusions are relatively inexpensive materials and have a variety of shapes. In addition, there is a high degree of freedom in joint spacing and spacing between bar steels with protrusions, depending on the target structure. A joint structure with a high degree can be provided.
Because it can resist the axial force in the cross section at the joint part, it is possible to eliminate the cutting beam and support work by connecting multiple steel pipe sheet piles and closing them into a cylindrical shape (especially circular) such as circular or oval. Reduction of construction cost and construction period can be realized.

  Next, the present invention will be described in detail based on the illustrated embodiment.

  First, the basic structure of the present invention will be described with reference to the first embodiment shown in FIGS. 1 and 2. In the present invention, a female joint 13 made up of a pair of L-shaped steel members 10 is used to increase the joint fitting space. And an L-L joint using a male joint 17 by a pair of L-shaped steel materials 14, and a stopper made of a rod-shaped steel material 18 with protrusions is disposed on the surface of the steel pipe sheet pile main pipe 3 between the joint legs 12, 16. . In the case of such an LL joint using the female joint 13 and the male joint 17, since the joint fitting space 25 is one chamber, a relatively large joint fitting space 25 can be formed. It has basic features that facilitate excavation of soil and sand in the joint, cleaning of the joint fitting space 25, and filling with a cement-based room temperature curable filler 26 such as mortar.

  Furthermore, such an advantage leads to reliable discharge of earth and sand in the joint fitting, reliable cleaning in the joint fitting space 25, and a solid mortar filling in the joint fitting space 25, and a steel sheet pile structure. The rigidity of the object or steel pipe sheet pile foundation 23 is greatly influenced. To explain further, the steel pipe sheet pile foundation is designed with a virtual well that takes into account the shear deviation of the joint. Therefore, when a horizontal force acts on the steel pipe sheet pile foundation at the pier, If shear force acts and the applied shear force exceeds the joint shear strength, the joint will be displaced and the bending rigidity of the entire pier will be reduced. Especially important because it affects.

  In addition, in the case where a protrusion protruding into the joint fitting space 25 is used, since adhesion of earth and sand at the protruding portion has a great influence on the joint shear performance, cleaning of the fitting joint, cement system such as mortar Filling with the room temperature curable filler 26 is even more important.

  More specifically, with reference to FIG. 1, a pair of L-shaped steel materials 10 are provided on one side outer surface of the steel pipe sheet pile main tube 3 in the outer surface axial direction with a predetermined interval, and the arm portions 11 of the L-shaped steel materials 10. Are arranged inward so as to approach each other, and the leg portions 12 of the respective L-shaped steel materials 10 are arranged in parallel, and the base end portions thereof are fixed by welding, so that a female joint 13 is configured. The arrangement interval of the pair of L-shaped steel members 10 increases the joint fitting space 25 formed by the female / male joint in the female / male joint fitting state and the outer peripheral surface of each steel pipe sheet pile main pipe 3. In order to increase the rigidity of the joint, it is desirable to widen the interval.

  Further, on the other outer surface of the steel pipe sheet pile main pipe 3, the pair of L-shaped steel members 14 are arranged outwardly in the axial direction so that the arm portions 15 of the L-shaped steel members 14 are separated from each other. At the same time, the leg portions 16 of the respective L-shaped steel materials 14 are arranged in parallel, and the base end portions thereof are fixed by welding to constitute a male joint 17. The distance between the pair of L-shaped steel members 14 in the male joint 17 allows the space between the leg portions 16 to be arranged in the female joint 13 in order to increase the joint inner space in the fitting state and increase the rigidity of the joint. So widely set.

  As described above, the steel pipe sheet pile main pipe 3 is provided with the female joint 13 on one side and the other side is provided with the male joint 17 and the steel pipe sheet pile 28 having the L-type female / male joint. Yes. In FIG. 1, the steel pipe sheet piles 28 are arranged in series and the joints are fitted to each other, the earth and sand in the joint fitting space 25 is excavated and discharged, the inside of the joint fitting space 25 is washed, and the fitting is fitted. The state where the cement-type room temperature curable material 26 made of mortar is filled and cured in the joint space 25 is shown.

  Here, in the construction of the steel pipe sheet pile, since the L-shaped steel material is built as a guide, if the fitting margin of the male and female joints is large, not only the built-in accuracy of the steel pipe sheet pile can be secured, but also the fitting space Since there are cases where it is extremely large or extremely small, it is not possible to ensure soil and sand cleaning in the fitting space and filling workability of the filler. Therefore, by setting the leg length of the L-shaped steel material of the male and female joints to different lengths, it is possible to ensure the accuracy of laying the steel pipe sheet pile and ensure the workability of excavating soil and injecting the filler in the joint. it can.

  As each of the L-shaped steel materials 10 and 14, for example, various L-shaped steel members such as various equilateral angle steels or unequal angle irons can be used, and therefore, steel pipe sheet piles adapted to the structure to be constructed. 1 can be configured.

  Further, the steel pipe sheet pile main pipe 3 of the portion sandwiched between the leg portions 12 in each L-shaped steel material 10 constituting the female joint 13 and the portion sandwiched between the leg portions 16 in each L-shaped steel material 14 constituting the male joint 17 are respectively shown. On the outer peripheral surface, a plurality of protruding bar-like steel members 18 are parallel to each other in the circumferential direction so as to extend in the steel pipe axial direction of the steel pipe sheet pile main pipe 3 over the entire length of the female joint 13 and the male joint 17 in the vertical direction. Is fixed by welding.

  Also, the spacing between the protruding bar-shaped steel members 18 is such that the protruding bar-shaped steel materials 18 are sufficiently adhered to the cement-based room temperature curable material 26 and exhibit the adhesion strength of the protruding bar-shaped steel materials 18. It is optimal to set the distance between the centers of the three or more of the diameters of the rod-shaped steel members 18 with projections to three times or more.

  For example, when the arrangement interval of the protruding bar-shaped steel members 18 is less than three times the diameter, as shown by a solid line in FIG. 6 (b), the substantially plane shear fracture surface connecting the tops of the protruding bar-shaped steel members 18 Although the shear fracture is caused by A, if the spacing is 3 times or more, as shown in FIG. 6 (a), shear by the shear fracture surface B curved to the top of the bar-shaped steel material 18 with protrusions and the bottom of the intermediate part between them. FIG. 6A has a larger shear fracture area and higher shear fracture resistance. Therefore, if the spacing between the protruding rod-shaped steel members 18 is less than three times, sufficient adhesion strength of the protruding rod-shaped steel materials 18 such as different diameter reinforcing bars cannot be exhibited. A sufficient adhesion strength of the bar-like steel material 18 can be exhibited.

The reason why the distance between the centers of the protruding bar-shaped steel materials is set to be at least three times the diameter of the protruding bar-shaped steel materials will be described in detail. The shear strength of a joint in which a rod-shaped steel material with protrusions is arranged on the outer peripheral surface of a steel pipe and filled with mortar can be classified into mortar shear failure and adhesion failure of rod-shaped steel materials with protrusions. Here, assuming that the arrangement interval between the centers of the rod-shaped steel materials with protrusions is L3, the diameter is d, the number of the rod-shaped steel materials is N, and the compressive strength of the mortar to be filled in the joint is σ, the resistance to shear fracture of the mortar (Pc ) Was determined experimentally to be determined by Equation 1.
Pc = L3 x 0.1σ x N (Formula 1)
On the other hand, it was clarified by the same experiment that the adhesion fracture strength (Pb) of the rod-shaped steel material with protrusions is determined by Equation 2.
Pb = 0.5πD x 0.2σ x N (Formula 2)
This is because the unilateral shear strength of the mortar is about 10% of the compressive strength of the mortar, whereas the adhesion strength of the bar steel with protrusions is about 20% of the compressive strength of the mortar. Here, in order for the joint part to exhibit a stable and reliable shear strength, it is necessary that an adhesion failure occurs, and in order for the shear fracture strength (Pc) to exceed the adhesion fracture strength (Pb) From the formulas 1 and 2, the following formula is derived.
L3> πD≈3D
That is, it is clear that the arrangement interval should be three times the diameter or more in order to sufficiently exhibit the stick-like steel material with protrusions.

  Although it is economical to use different diameter reinforcing bars or different diameter steel bars or barbed diameter steel bars as the protrusion-shaped bar steel materials 18, in order to improve the adhesion strength at intervals in the longitudinal direction of the bar steel materials. Any rod-shaped steel material having a large number of protrusions may be used.

  As in the above-described embodiment, in the present invention, the reason why the rod-shaped steel material with protrusions is arranged in the vertical direction as a displacement preventing member on the steel pipe surface in the steel pipe sheet pile main pipe 3 is that continuous welding is possible, and automatic welding is easy. This is because the processing cost can be greatly reduced.

  As described above, other methods in which the rod-shaped steel material with protrusions is not arranged vertically are conceivable. For example, (a) a steel pipe sheet pile main tube 3 itself formed by winding a band-shaped steel plate with protrusions spirally has an external protrusion. A method using a steel pipe, (b) a method of installing a large number of headed studs on the outer peripheral surface of the steel pipe sheet pile main pipe 3, and (c) a large number of short bar-shaped steel members spaced vertically and attached in a horizontal direction by welding. There is a way.

  However, if the steel pipe sheet pile main pipe with the outer protrusion (a) is used, the material cost increases. In addition, when the headed stud of (b) is installed, not only the processing cost is increased, but also resistance occurs when the steel pipe sheet pile is built in the ground, and the headed stud may be damaged. Moreover, it becomes an obstacle to the cleaning excavation work in the joint space. Moreover, the method of attaching the rod-shaped steel material (c) by welding in the horizontal direction attaches a large number of short rod-shaped steel materials, and as a whole, the welding extension is long and the processing cost is high. Therefore, in the present invention, the rod-shaped steel material with protrusions is installed in the vertical direction as described above. Further, from the viewpoint of cost reduction, it is desirable to use a different diameter reinforced steel bar or the like as the bar-shaped steel material with protrusions.

  The above-described construction margin and the interval required for the soil washing and filling operation inside the joint will be described with reference to FIGS. First, each figure of (a), (b), and (c) in FIG. 2 shows the length of the leg portion 12 of the L-shaped steel material 10 in the female joint 13 and the length of the leg portion 16 of the L-shaped steel material 14 in the male joint 17. The fitting state when the length is longer than the above is shown. (A) shows a neutral fitting state with a margin in the approaching direction or away from the male and female joints, and (b) shows the male and female joints being closest. In this state, a compression fitting state with a margin only in the direction of separation is shown, and (c) shows a tensile fitting state with a margin only in the approaching direction in a state where the male and female joints are separated most. In other words, the fitting margin is defined by the leg length of the male joint, and the interval necessary for the earth and sand excavation and the filling material injection is defined by the leg length of the female joint.

  3 (a), 3 (b), and 3 (c), the length of the leg portion 16 of the L-shaped steel material 14 in the male joint 17 is the same as the length of the leg portion 12 of the L-shaped steel material 10 in the female joint 13. In the same manner as described above, (a) shows a neutral fitting state, (b) shows a compression fitting state, and (c) shows a tension fitting state. Is shown. That is, the fitting margin is defined by the leg length of the female joint, and the interval necessary for the earth and sand excavation and the filling material injection work is defined by the leg length of the male joint. 2 and 3 show a form in which a bar-shaped steel material 18 having protrusions made of four different diameter reinforcing bars is fixed to the outer peripheral surface of the steel pipe sheet pile main pipe 3 at intervals in the circumferential direction by welding.

  Here, the fitting margin D is equal to the outer surface of the arm portion 15 of the male joint 17 and the arm portion 11 of the female joint 13 shown in FIG. 2B or 3B in the linear series connection direction. The dimension D1 between the inner surface and the direction perpendicular to the inner surface D1 is a portion E between the tip of each arm portion 11 of the female joint 13 and the outer surface of each leg portion of the male joint 17, or each of the female joints 13 This is a portion F between the inner surface of the leg portion 12 and the tip of each arm portion of the male joint 17. Although the fitting margin shown by the dimension D1 differs depending on the diameter and length of the steel pipe sheet pile main pipe, when the steel pipe diameter is targeted for 600 mm to 2000 mm, 40 mm to ensure the accuracy of installing the steel pipe sheet pile. It is desirable to be about 80 mm. In addition, the above E and F need to be smaller than the dimension D1 and desirably about 10 mm to 30 mm because there is a possibility that the joint portion may be detached when the fitting margin becomes large.

  Next, a fitting space necessary for earth and sand excavation in the joint and filling workability will be described. There are two methods for excavating sediment in the joint: a water jet method and an air lift combined method for facilitating sediment discharge. It is necessary to insert a device for carefully excavating and cleaning the wide joint fitting space into the joint, and it is desirable to widen the minimum gap between the steel pipes, but if it becomes too wide, the joint shear strength decreases. Since there is a fear, it is desirable that the minimum interval between the steel pipes be 150 mm to 250 mm.

  Furthermore, although the arrangement | positioning space | interval of the male joint 17 and the female joint 13 can be set with the construction workability | operativity in a joint, and a cross-sectional axial force (compressive force or tensile force of the circumferential direction), these arrangement | positioning space | intervals are Practically, it is desirable that the arrangement interval be 300 mm or more and ½ or less the steel pipe diameter of the steel pipe sheet pile main pipe 3 (the arrangement interval is 300 mm to 1000 mm or less when the steel pipe diameter is 600 mm to 2000 mm).

Further, when the above points are specifically examined, when each L-shaped steel material 10 (14) is attached to the outer peripheral surface of the steel pipe sheet pile main pipe 3, the positional relationship between these attachment positions and the central axis C in the joint connecting direction. Will be described with reference to FIG. The mounting position P of the leg portion 12 (16) in each L-shaped member 10 (14) facing the central axis C of the steel pipe sheet pile main pipe 3 in the serial connection direction at equal intervals (L), and the L-shaped member 10 ( 14), the dimensional difference L2 in the central axis direction with respect to the attachment center position (position on the central axis C) Q (the male joint side is omitted) is expressed by Equation 3 when the radius of the steel pipe sheet pile main pipe 3 is R. Can be calculated.
Here, assuming that the diameter of the steel pipe sheet pile main pipe 3 is 600 mm to 2000 mm, the positions of the legs 12 in the L-shaped steel material 10 are attached at intervals of 1/3 of the steel pipe diameter of the steel pipe sheet pile main pipe 3. In this case, the dimensional difference L2 is calculated by Equation 3 and is about 20 to 60 mm. For example, when the fitting margin D in the direction of connecting in series is set to 60 mm, and the plate thickness of the L-shaped member 10 (14) is set to about 15 mm, the distance to the arm portion 11 of the L-shaped member 10 (14) is reached. The length of the leg 12 is 110 mm to 150 mm.

  The fitting margin D of 60 mm is an example, and the fitting margin D is preferably about 40 mm to 80 mm. When the fitting margin D is less than 40 mm, fitting work is performed when a large number of steel pipe sheet piles are installed in a closed ring. If the fitting margin exceeds 80 mm, the construction accuracy may be lowered.

  In order to ensure soil excavation and filling workability in the joint, it is necessary to set the interval between the steel pipe sheet pile main pipes to 150 mm to 250 mm. Therefore, it sets so that the space | interval of a steel pipe sheet pile main pipe | tube is ensured with the leg part length of the L-shaped steel material with a longer leg part length in a male and female joint. That is, the interval between the steel pipe sheet pile main pipes is 180 mm, and the dimensional difference L2 is about 20 mm to 60 mm. Therefore, the leg length of the L-shaped steel material is 200 mm to 240 mm.

  As described above, the leg length of the L-shaped steel material necessary to ensure the accuracy of embedding the steel pipe sheet pile, and the leg length of the L-shaped steel material necessary to ensure the soil excavation and filling material workability in the joint. I showed how to set up. However, since the leg lengths of these L-shaped steel materials differ depending on the steel pipe diameter and the arrangement interval of the L-shaped steel materials, the leg lengths can be freely determined after actually setting the dimensions.

  Next, in addition to the point that the bar steel with projections is installed on the outer peripheral surface of the steel pipe sheet pile main pipe 3, it is possible to further increase the shear strength of the joint portion. To explain.

  In the form shown in FIG. 4, a protrusion 19 is provided on the inner surface side that is the joint fitting space side of the opposing leg portion 12 in each L-shaped steel material 10 that constitutes the female joint 13, or each L-shape that constitutes the male joint 17. With the form which provided the protrusion 20 in the inner surface side used as the joint fitting space side of the leg part 16 in which the steel material 14 opposes, the adhesion with the cementitious hardening material with which a fitting joint is filled is improved. is there.

  Moreover, as a method of providing protrusions on the surface of the L-shaped steel material 10 (14), although not shown, a method of forming a band-shaped striped steel sheet or a band-shaped steel sheet with protrusions having protrusions into an L-shaped cross section, As shown in FIG. 5, on the surface of the L-shaped steel materials 10 and 14 having a flat surface, a protruding rod-shaped steel material 21 similar to the protruding rod-shaped steel material 18 used in the above embodiment is used. 14 may be arranged in the vertical direction on the inner surface facing the joint fitting space of the leg 12 (16) 14 and fixed by welding or the like. As shown in the figure, the protrusion-like rod-shaped steel material 21 may be attached to each L-shaped steel material 10 or 14 in advance, or after each L-shaped steel material 10 or 14 is attached to the steel pipe sheet pile main pipe 3. Good.

Next, the joint shear test of the joint part which filled and hardened the mortar in the fitting joint was independently carried out by the inventor by using the LL joint by the female joint 13 and the male joint 17 of the above embodiment. As a result, in a push-out shear test of a joint in which a steel pipe sheet pile main pipe 3 is provided with a 22 mm diameter rebar in the outer surface of the steel pipe, 1000 kN / m when the mortar strength filled in the joint is 20 N / mm ^2. When the shear strength was 5 times the shear strength of the conventional joint shown in FIG. 9 and the mortar strength was 40 N / mm ² , 2000 kN / m (10 times the shear strength of the conventional joint) was confirmed.

  Further, in the above experiment, as shown in FIG. 6 (b), different diameter reinforcing bars 18a are all used as the plurality of rod-shaped steel members 18 with projections fixed to the outer surface of the steel pipe sheet pile main pipe 3 by welding. Tests with different arrangement intervals of the diameter reinforcing bars 18a were carried out, but when the arrangement interval L3 between the different diameter reinforcement bars is less than three times the diameter of the different diameter reinforcement bars 18a, a substantially planar shape connecting the tops of the different diameter reinforcement bars 18a. When a shear fracture occurs due to the shear fracture surface A, and as shown in FIG. 6 (a), when the disposition interval L3 between the different diameter reinforcing bars is more than three times the diameter of the different diameter reinforcing bars 18a, The shear fracture surface between the diameter reinforcing bars becomes a shear fracture surface B curved so as to approach the surface of the steel pipe sheet pile main pipe 3, and the punching force necessary for the shear fracture is also increased.

  From the above, it has been found that if the arrangement interval L3 between the different diameter reinforcing bars is less than three times the diameter of the different diameter reinforcing bars, sufficient adhesion strength of the different diameter reinforcing bars cannot be exhibited. Therefore, by disposing the arrangement interval L3 between the different diameter reinforcing bars at intervals of three times or more the diameter of the different diameter reinforcing bars, sufficient adhesion strength of the different diameter reinforcing bars, that is, the rod-shaped steel material 18 with projections, is exhibited. Can do.

  10 and 11, steel pipe sheet piles having joints according to the embodiment of the present invention are arranged in series, and the joints of the steel pipe sheet piles are engaged with each other and placed on the bottom bottom ground 24. The steel pipe sheet pile foundation 23 in the state of a temporary cut-off wall that also serves as a part of the main body structure is shown. Yes.

  In the tubular pipe sheet pile foundation 23 as described above, after excavating the earth and sand in the joint fitting in which the female joint 13 and the male joint 17 of the steel pipe sheet pile adjacent to each other in series are engaged, By filling and hardening the mortar 5 in the joint portion, the joint portion has a structure capable of resisting axial force (circumferential compression force or tensile force due to earth pressure / water pressure). In addition, since the steel pipe sheet pile foundation 23 has a structure capable of resisting the force in the out-of-plane direction of the well-shaped cross section, the abdomen or the cut beam as shown in FIGS. 12 and 13 and the temporary support for supporting them. Work can be omitted, and the construction cost can be reduced and the construction period can be greatly shortened.

  It can resist the axial force in the circumferential direction as described above, and the effect of omitting temporary support work or reducing the construction cost and shortening the construction postscript is particularly effective when the cross-sectional shape of the well-shaped steel pipe sheet pile foundation 23 is a circular cross section. It is valid. When the cross-sectional shape is circular, earth pressure and water pressure acting on the tubular steel pipe sheet pile foundation 23 act as loads in the hoop direction (compressive force or tensile force), and only axial force in the circumferential direction acts in the joint. Therefore, in the case of the LL joint using the female joint 13, the male joint 17, and the rod-shaped steel material 18 with the projection as in the above-described embodiment capable of transmitting the axial force in the circumferential direction, temporary support work is performed. It can be omitted greatly.

  In addition, in the steel pipe sheet pile foundation 23, the steel pipe of the steel pipe sheet pile main pipe 3 may be filled with concrete, and the bending rigidity of the steel pipe sheet pile is improved by filling the steel pipe sheet pile main pipe 3 with concrete in this way. be able to. Moreover, even when a large axial force (compression force or tensile force) in the circumferential direction acts on the steel pipe sheet pile foundation 23, the steel pipe itself constituting the steel pipe sheet pile main pipe 3 can be resisted without being crushed.

  In addition, the code | symbol 27 in FIG. 10 is the bottom plate concrete integrated inside a steel pipe sheet pile, and although illustration is abbreviate | omitted on this bottom plate concrete 27 as one construction form after constructing this bottom plate concrete, it is a reinforced concrete. The top plate made of steel and the frame of the concrete structure are started up, the upper structure is built, and the upper part of the steel pipe sheet pile foundation 23 is cut underwater near the top plate.

  As in the above-described embodiment, in the present invention, no member that divides or divides the space 25 in the left-right direction, the front-rear direction, or the up-down direction is disposed in the joint fitting space 25. Since the projection 19 and the rod-shaped steel members 18 and 21 with projections are also small in the projecting dimension from the surface of the L-shaped steel material or the outer peripheral surface of the steel pipe sheet pile main pipe, , There is no big obstacle.

It is a cross-sectional top view which shows the steel pipe sheet pile joint structure using the steel pipe sheet pile joint of 1st Embodiment of this invention, and the steel pipe sheet pile provided with the joint. It is a cross-sectional top view which shows the steel pipe sheet pile joint and steel pipe sheet pile joint structure of other embodiment of this invention. It is a cross-sectional top view which shows the steel pipe sheet pile joint and steel pipe sheet pile joint structure of other embodiment of this invention. It is a top view which shows one form in the case of providing a protrusion in the opposing surface of the opposing L-shaped steel material. FIG. 6 shows a form in which a different diameter steel bar is fixed to the inner surface of a flat arm of an opposing L-shaped steel material to form a joint piece with an inner surface protrusion, and (a) is one of female joints, (b ) Is a schematic perspective view showing a case of using one of the male joints. (A) And (b) is explanatory drawing for demonstrating the difference in the shear fracture surface of the mortar at the time of changing the installation space | interval of a rod-shaped steel material with a protrusion. It is explanatory drawing for demonstrating the difference of a L-shaped member attachment position and a L-shaped member attachment position center. (A) (b) (c) is a top view which shows the conventional joint structure, respectively. It is a top view which shows the steel pipe sheet pile joint structure in the steel pipe sheet pile foundation etc. by the conventional PP joint. BRIEF DESCRIPTION OF THE DRAWINGS One Embodiment of the steel pipe sheet pile foundation by the steel pipe sheet pile joint structure of this invention is shown, Comprising: (a) is a top view, (b) is a vertical front view. It is a top view which expands and shows a part of Fig.10 (a). It shows one form of the steel pipe sheet pile foundation by the conventional steel pipe sheet pile joint structure, (a) is a top view, (b) is a longitudinal front view. The other form of the other steel pipe sheet pile foundation by the conventional steel pipe sheet pile joint structure is shown, Comprising: (a) is a top view, (b) is a vertical front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel pipe sheet pile 2 Steel pipe sheet pile structure or steel pipe sheet pile foundation 3 Steel pipe main pipe 4 Joint steel pipe 4a Female joint 4b Female joint 5 Mortar 6 Slit 7 Temporary cut-off part 8 Joint part 9 Cross beam 10 L-shaped steel 11 Arm part 12 Leg part 13 Female joint 14 L-shaped steel material 15 Arm portion 16 Leg portion 17 Male joint 18 Protruding rod-shaped steel material 18a Different diameter rebar 19 Protrusion 20 Protrusion 21 Protruding rod-shaped steel material 23 Steel pipe sheet pile foundation 24 Submarine ground 25 Joint fitting space 26 Cement-based room temperature hardening Filler 27 Bottom plate concrete 28 Steel pipe sheet pile

Claims (6)

  A female joint in which a pair of L-shaped steel members are arranged at a predetermined interval in the axial direction of the outer surface of the steel pipe sheet pile main body, the arm portions of the L-shaped steel materials are arranged inward, and the leg portions of the L-shaped steel materials are fixed A pair of L-shaped steel members having a predetermined interval in the axial direction of the outer surface of the steel pipe sheet pile main body, the arm portions of the respective L-shaped steel materials being arranged outwardly, and the leg portions of the respective L-shaped steel materials being fixed In steel pipe sheet pile joints connected by mold joints, a plurality of rod steel members with protrusions are provided with protrusions in the outer peripheral direction of the main pipe, sandwiched between the L-type steel materials of the female joint and the male joint. A steel pipe sheet pile joint, which is arranged and fixed so as to extend in the direction of the main pipe axis while being arranged at an interval of three times or more the diameter of the rod-shaped steel material.   The leg length of the L-shaped steel material forming the pair of female joints has a length necessary to ensure the accuracy of installing the steel pipe sheet pile, and the leg of the L-shaped steel material forming the pair of male joints 2. The steel pipe sheet pile joint according to claim 1, wherein the length of the steel pipe is a length necessary for ensuring excavation of earth and sand in the joint and filling workability.   The leg length of the L-shaped steel material forming the pair of male joints has a length necessary to ensure the accuracy of installing the steel pipe sheet pile, and the leg of the L-shaped steel material forming the pair of female joints 2. The steel pipe sheet pile joint according to claim 1, wherein the length of the steel pipe is a length necessary for ensuring excavation of earth and sand in the joint and filling workability.   The steel pipe sheet pile joint according to any one of claims 1 to 3, wherein the pair of L-shaped steel materials have protrusions on opposing surfaces.   In the joint structure of the steel pipe sheet pile foundation using the joint according to any one of claims 1 to 4, a space surrounded by the steel pipe sheet pile main pipe and the joint member is filled with a cement-based filler. Steel pipe sheet pile foundation joint structure.   A steel pipe sheet pile foundation formed by connecting and closing a plurality of steel pipe sheet piles, wherein the steel pipe sheet pile foundation using the joint according to any one of claims 1 to 4 is closed in a cylindrical shape.

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