JP5280389B2 - Cushion material for propulsion pipe and propulsion pipe - Google Patents

Description

  The present invention relates to a cushion material for a propulsion pipe used in a joint of the propulsion pipe in the propulsion method and a propulsion pipe provided with the cushion material.

  The propulsion method is widely adopted as a construction method for burying pipes underground, such as public sewerage work. The propulsion method is a construction method in which a pipe is buried in the ground by, for example, sequentially extruding a concrete pipe into the ground without excavating the entire range in which the pipe is buried. Hereinafter, in this specification, the pipe buried in the ground is referred to as a “propulsion pipe”.

  As the material for the propulsion pipe used in the above-mentioned propulsion method, a material made of concrete, resin concrete, ceramic, or iron is often used. Therefore, when pushing out the propelling pipes, if the propelling pipes come into contact with each other, the contacted parts are likely to be damaged. In order to prevent breakage of the propulsion pipe and transmit propulsive force for propelling the propulsion pipe, a propulsion pipe cushioning material that functions as a thrust transmission member is attached to the end of the propulsion pipe.

  As the cushion material for propulsion pipes, those made of polystyrene foam, plywood, particle board, etc. are used. A cushioning material made of expanded polystyrene is widely used. A suitable example of such a thrust transmission material is described in Patent Document 1, and this thrust transmission material is a low-magnification foam molded product made of expanded polystyrene and having a specific gravity of 0.3 to 0.8. It is a plate member having a ring shape as a whole.

  On the other hand, the cushion material, which is an elastic material, undergoes bulge deformation in the radial direction due to pressure acting during propulsion. Therefore, unless the radial width and the mounting position are appropriately adjusted, there is a problem that the radial direction protrudes outward from the propulsion pipe. Since the protrusion of the cushion material at the outer periphery of the propulsion pipe may cause deformation of the collar provided on the outer periphery of the propulsion pipe, the width of the cushion material in the radial direction is conventionally made smaller than the wall thickness of the propulsion pipe, At times, positioning was performed so as not to protrude from the pipe cross section, and a cushion material was installed.

  In the case of a large propulsion pipe whose outer diameter exceeds 1 m, a ring-shaped cushion material is divided into a plurality of parts, and bonded together while positioning the pipe cross section with an adhesive or the like when used. However, there is a problem that the work efficiency is poor because it requires very skill for positioning and requires labor to press down until the adhesive dries to prevent misalignment. It was. A cushion material for a concrete propulsion pipe that solves this problem is described in Patent Document 2.

  In this case, as shown in FIG. 7, in the foamed polystyrene cushion material 1 forming a plurality of rings, protrusions 2 are provided on the outer peripheral portion. The concrete propulsion pipe cushioning material 1 can be easily positioned by bringing the protrusion 2 on the outer peripheral portion into contact with the collar provided on the outer peripheral portion of the propulsion pipe, and only the tip of the protrusion 2 is in contact with the collar. Therefore, it is possible to limit the influence of bulging caused by crushing due to the Poisson's ratio of the cushion material that occurs during propulsion to only a narrow region that is the tip of the projection 2, thereby preventing the collar from being deformed. .

Japanese Patent Publication No. 61-8320 JP-A-8-82192

  As described above, the concrete propulsion pipe cushion material shown in FIG. 7 can effectively prevent the collar attached to the propulsion pipe from being deformed during propulsion. However, by forming the protrusion on the outer peripheral portion, a region without a cushioning material is formed between the collar and the region in surface contact with the end surface of the propelling tube, the protrusion by the region without the cushioning material. It becomes narrow compared with what it does not have. Therefore, the dispersion of stress is suppressed, and the stress acting on the end surface of the propulsion pipe via the cushion material is concentrated compared to the case where the cushion material is in surface contact over the entire end surface. As a result, the cushion performance is reduced as compared with a cushion material that is in surface contact with the entire end face of the propulsion pipe and exhibits high stress dispersibility.

  The present invention has been made in view of the above circumstances, and can be positioned easily, but can also achieve a high stress dispersion effect, and the side where the collar is attached to the cushion material for the thrust tube It is an object of the present invention to provide a propulsion pipe fixed to the end face of the motor.

  The cushion material for a propulsion pipe according to the present invention is a plate member including at least a first side surface positioned substantially parallel at a predetermined distance, an outer peripheral surface positioned on the outer peripheral edge side of the second side surface and both side surfaces, and A propulsion pipe cushioning material having a ring shape as a whole, wherein A is the diameter from the center of the ring to the outer peripheral edge of the first side surface, B is the diameter from the outer peripheral edge of the second side surface, and When the diameter to an arbitrary position in the axial direction is C, A ≧ B and A> C.

  In a preferred embodiment, the propulsion tube cushion material according to the present invention satisfies A> B, and the outer peripheral surface is an inclined surface continuous from the outer peripheral edge of the first side surface toward the outer peripheral edge of the second side surface. It is characterized by.

  In the above-mentioned cushion material for a propelling pipe, the outer peripheral surface is located radially inward from the positions of the outer peripheral edges of the first side surface and the second side surface. Therefore, even if either or both of the outer peripheral edges of the first side surface and the second side surface are in contact with the cylindrical collar attached to one end side of the propulsion tube, the outer peripheral surface is in contact with the collar. There is no contact, and a space is formed between the inner peripheral surface of the collar and the outer peripheral surface of the cushion material for the propelling tube.

  Therefore, in the cushion material for a propulsion pipe according to the present invention, both or one of the outer peripheral edges of the first side face and the second side face are in contact with a cylindrical collar attached to one end side of the propulsion pipe. As a result, positioning with respect to the propulsion pipe is facilitated, and the expansion of the cushion material in the radial direction can be absorbed in the above-described space, and deformation of the collar due to the expansion can be prevented.

  Furthermore, the cushion material for a propulsion pipe according to the present invention is entirely ring-shaped and has no protrusions. For this purpose, by covering the entire end face of the propelling pipe on the side on which the collar is attached on the first side surface, the stress distribution acting on the end face of the propelling pipe through the cushion material during construction is reduced. Can be exerted on the entire end face. Thus, the cushioning effect of the propulsion pipe cushioning material is improved, and the propulsion pipe can be effectively prevented from being damaged due to the concentration of stress.

  When the propelling pipe cushioning material according to the present invention is a propelling pipe having a small outer diameter, the whole can be obtained as an integrally molded product. However, when used for a large propulsion pipe whose outer diameter exceeds 1 m, the propulsion pipe cushion material is composed of two or more cushion material pieces having substantially the same shape divided in the circumferential direction. It is preferred that Even in that case, each cushion material piece is designed to satisfy the condition of A ≧ B and A> C.

  When the cushion material for a propulsion pipe according to the present invention is constituted by the plurality of cushion material pieces described above, the left and right side end surfaces of each cushion material piece can be inclined end surfaces. In this aspect, when the cushion material for the ring-shaped propulsion pipe composed of a plurality of cushion material pieces is compressed during propulsion, the cushion material piece bulges in the circumferential direction. It can be absorbed in a V-shaped space formed between them, and it is possible to suppress waving and peeling that occur when cushion material pieces are pressed against each other by swelling.

  The present invention further includes any one of the above-mentioned cushion materials for a propulsion pipe, wherein a cylindrical collar is attached to one end side of the propulsion pipe, and the first side surface is in contact with the end face on the side where the collar is attached. Also disclosed is a propelling tube characterized in that is fixed.

  In this propulsion pipe, stress acting on the end face can be effectively dispersed through the propulsion pipe cushioning material, so that the end face side can be prevented from being damaged by concentrated stress during construction. It is also possible to avoid deformation of the collar during propulsion.

  According to the present invention, it is possible to obtain a cushioning material for a propulsion tube that can be expected to have a high stress dispersion effect while being easily positioned, and that can prevent deformation of a collar attached to the propulsion tube. Moreover, the propulsion pipe which can avoid that an end surface is damaged by concentrated stress is obtained.

Sectional drawing which follows the longitudinal direction of the propulsion pipe connection part using the cushion material for propulsion pipes by this invention. The figure explaining the arrangement | positioning condition of the cushion material piece for propulsion pipes in the propulsion pipe by this invention. The perspective view (FIG. 3 (a)) which shows an example of the cushion material piece in the cushion material for propulsion pipes by this invention, and sectional drawing (FIG.3 (b)) which follows the bb line of Fig.3 (a). The figure corresponded in FIG.3 (b) which shows the other example of the cushion material piece in the cushion material for propulsion pipes by this invention. The perspective view (Drawing 5 (a)) which shows other examples of the cushioning material piece in the cushioning material for propulsion pipes by the present invention, and the sectional view which meets the bb line of Drawing 5 (a) (Drawing 5 (b)). The front view which shows a part when the cushion material piece shown in FIG. 5 is connected in ring shape. The figure which shows an example of the conventional cushion material for propulsion pipes.

  Embodiments of the present invention will be described below with reference to the drawings.

  In FIG. 1, 10 is a cylindrical propulsion pipe made of concrete, for example, and L is a central axis. A cylindrical collar 11 made of a steel plate or the like is attached to the rear end portion (receiving port side) of the propulsion tube 10A on the propulsion front side, and the front end portion (inlet side) of the propulsion tube 10B on the propulsion rear side is somewhat reduced in diameter. ) Enters the collar 11. On the rear end surface 12 of the front propulsion pipe 10A, a ring-shaped propulsion pipe cushioning material 20 is attached using an adhesive or the like so that the central axis is the central axis L, and the propulsion pipe 10A The front end portion of the propulsion pipe 10B enters the collar 11 as described above, and the front end face 13 abuts against the cushion material 20 for the propulsion pipe. In addition, the material of the cushion material 20 for propulsion pipes may be the same as the cushion material for propulsion pipes conventionally used, for example, the low magnification foam molding which is a product made from a polystyrene foam and has specific gravity of 0.3-0.8. It is a product. In FIG. 1, reference numeral 14 denotes an appropriate sealing material, and reference numeral 15 denotes a filling margin such as mortar formed on the inner diameter side of the rear end face of the propulsion pipe 10A.

  FIG. 2 is a cross-sectional view taken along line aa in FIG. 1. In the illustrated example, the propulsion pipe cushion material 20 includes a plurality of substantially fan-shaped cushions divided in the circumferential direction (in the illustrated example). 16 pieces) of cushion material pieces 20a. Hereinafter, the cushion material 20 for a propulsion pipe according to the present invention will be described using the cushion material piece 20a as an example.

  As shown in FIG. 3, the sectoral cushion material piece 20 a includes a first side surface 21 and a second side surface 22, an outer peripheral surface 25, and left and right side end surfaces 26 that are positioned substantially parallel to each other at a predetermined distance s. , 27 and an inner peripheral surface 28, and a plate member having a thickness s.

  The outer peripheral edge 23 of the first side surface 21 and the outer peripheral edge 24 of the second side surface 22 form an arc, and the center of the arc, that is, the central axis of the cylindrical propulsion tube 10 as shown in FIG. A distance (curvature radius) A from L to the outer peripheral edge 23 of the first side surface 21 is larger than a distance (curvature radius) B from the central axis L to the outer peripheral edge 24 of the second side surface 22.

  Further, in the illustrated example, the outer peripheral surface 25 existing between the outer peripheral edge 23 and the outer peripheral edge 24 is an inclined surface continuously inclined from the outer peripheral edge 23 toward the outer peripheral edge 24 side. That is, when the distance (curvature radius) from the central axis L to an arbitrary position in the direction of the central axis L of the outer peripheral surface 25 is C, the relationship of A> C is established. Although not essential, in the illustrated example, the inner peripheral surface 28 is a cylindrical surface.

  In the cushion material piece 20a, the distance from the outer peripheral edge 23 to the inner peripheral face 28 on the first side face 21 is preferably substantially the same as the radial length of the rear end face of the propulsion pipe 10A (note that In the example shown in FIG. 1, a filling allowance 15 is formed on the inner diameter side of the rear end face of the propulsion pipe 10 </ b> A, and the distance from the outer peripheral edge 23 to the inner peripheral face 28 on the first side face 21 correspondingly. Is shorter, but this is not required). A distance (curvature radius) A from the center axis L to the outer peripheral edge 23 of the first side surface 21 is a distance (curvature radius) D from the center axis L to the collar 11 on the rear end surface 12 of the propulsion pipe 10A. (See FIG. 1).

  When starting the propulsion method, the cushion material piece 20a is pasted with an adhesive so that the first side face 21 side is the rear end face 12 side over the entire circumference of the rear end face 12 of the propulsion pipe 10A. wear. Since the radius of curvature A of the outer peripheral edge 23 of the first side surface 21 is equal to the radius of curvature D of the outer peripheral edge in contact with the collar 11 on the rear end surface 12 of the propelling tube 10A, the operator changes the outer peripheral edge 23 to the collar 11. By attaching all the cushion material pieces 20a while positioning them in contact with each other, as shown in FIG. 2, it is possible to easily form a ring-shaped propulsion pipe cushion material 20 consisting of 16 cushion material pieces 20a. Can do. The formed propulsion tube cushion material 20 covers the entire rear end surface 12 of the propulsion tube 10A.

  The propulsion pipe 10A is buried in the ground, the propulsion pipe 10B is inserted into the collar 11 at the rear end thereof, and the propulsion method is continued. As shown in FIG. 1, the front end surface 13 of the rear propulsion tube 10B comes into contact with the second side surface 22 of the propulsion tube cushion material 20 (cushion material piece 20a), and the cushion material piece 20a is compressed and the propulsive force is increased. Communicated. The cushion material piece 20a bulges in the radial direction by the compression, and the bulge appears to push the inclined outer peripheral surface 25 of the cushion material piece 20a to the outside. However, since the outer peripheral surface 25 is inclined as described above, a space p is formed between the outer peripheral surface 25 and the inner peripheral surface of the collar 11 as shown in FIG. The bulge, that is, the outward pushing portion is absorbed in the space p and does not exert a large force on the collar 11. For this reason, the collar 11 is not deformed. The outer peripheral edge 23 of the first side surface 21 is in contact with the inner peripheral surface of the collar 11, and the outward bulge of the portion acts as a force on the collar 11, but the contact area is small and the collar 11 is deformed. It will not be the power to cause.

  The propulsive force is transmitted to the forward propelling tube 10A via the first side surface 21 of the cushion material piece 20a. As described above, the first side surface 21 of the cushion material piece 20a is transmitted to the propulsion tube 10A. The entire surface of the rear end face 12 can be brought into surface contact, and the stress acting on the rear end face 12 of the propulsion pipe 10A through the cushion material piece 20a during the construction is distributed over the entire rear end face 12 of the propulsion pipe 10A. be able to. Thereby, the cushioning effect of the propulsion pipe cushioning material 20 (cushioning material piece 20a) is improved, and it is possible to effectively avoid the breakage of the propelling pipe 10A due to the concentration of stress.

  The size relationship between the second side surface 22 and the area of the cushion material piece 20a and the area of the front end surface 13 of the propulsion pipe 10B may be arbitrary, but the area of both is equal or the second side surface 22 is slightly larger. The embodiment is a preferred embodiment.

  FIG. 4 shows another aspect of the cushion material piece 20a in cross-section, and portions corresponding to the cushion material piece 20a shown in FIG. In FIG. 4A, the above-described distance (curvature radius) A and distance (curvature radius) B are equal. And the said outer peripheral surface 25 which exists between the outer periphery 23 and the outer periphery 24 is comprised by the two inclined surfaces 25a and 25b which incline in the opposite direction, and the center part of the width direction is made the lowest. The inclined surfaces 25a and 25b are connected. In the cushion material piece 20a shown in FIG. 4 (b), the outer peripheral surface 25 has a cross-sectional shape that is curved in an arc shape toward the center.

  FIG. 5 shows still another aspect of the cushion material piece 20a in cross section. 5A is a perspective view, and FIG. 5B is a cross-sectional view taken along the line bb in FIG. 5A. The cushion material piece 20a shown in FIG. 5 is such that the left and right side end faces 26a and 27a are inclined so that the second side face 22 side becomes narrow as shown in FIG. This is different from the cushion material piece 20a shown in FIG. The other structure is the same, and the same code | symbol is attached | subjected to the same member.

  FIG. 6 shows a state when a plurality of the cushion material pieces 20a shown in FIG. 5 are bonded to the rear end surface 12 of the propulsion pipe 10A in a ring shape as shown in FIG. As shown in the drawing, each cushion material piece 20a has the left and right side end faces 26a, 27a inclined in the direction in which the second side face 22 becomes narrower than the first side face 21, so A V-shaped space p1 is formed between one side end face 26a and the other side end face 27a of 20a. When the ring-shaped propulsion tube cushion material 20 is compressed during propulsion, the cushion material piece 20a swells in the circumferential direction, but the V-shaped space p1 can absorb the bulge in the circumferential direction. In the cushion material piece 20a of this form, it is possible to suppress undulation and peeling that occur when the cushion material pieces are pressed against each other by swelling.

L ... Center axis of the propulsion pipe,
10, 10A, 10B ... propulsion pipe,
11 ... Color,
12 ... rear end surface of the propulsion pipe,
13 ... front end face of propulsion pipe,
20 ... Ring-shaped propulsion pipe cushioning material,
20a ... Cushion material piece 21 constituting the cushion material for the propelling pipe ... First side surface,
22 ... the second side,
23 ... outer peripheral edge 24 of the first side surface ... outer peripheral edge of the second side surface,
25 ... outer peripheral surface,
26, 27 ... right and left side end faces,
28 ... Inner surface,
L ... Center axis of the propulsion pipe,
A: Distance (curvature radius) from the central axis L of the cylindrical propulsion tube to the outer peripheral edge of the first side surface,
B: Distance (curvature radius) from the central axis L of the cylindrical propulsion tube to the outer peripheral edge of the second side surface,
C: Distance from the central axis L of the cylindrical propelling pipe to an arbitrary position in the direction of the central axis L of the outer peripheral surface,
D: Distance (curvature radius) from the central axis L to the collar on the rear end face of the propulsion tube.

Claims (5)

One Katatan cylindrical in side collar is attached, on the end face of the side fitted with the collar, the first and second sides and both sides lying parallel substantially at a predetermined distance A cushion member for a propulsion pipe that is a plate member having at least an outer peripheral surface located on the outer peripheral edge side and has a ring shape as a whole, and has a diameter (curvature radius) from the center of the ring to the outer peripheral edge of the first side surface. A ≧ B, where A, the diameter (curvature radius) to the outer peripheral edge of the second side surface is B, and the diameter (curvature radius) to an arbitrary position in the axial direction of the outer peripheral surface is C, and then in contact said first side surface of the propulsion tube cushioning material is a> C, propulsion tube, characterized in that it is fixed. The propulsion pipe according to claim 1, wherein the cushion material for the propulsion pipe is composed of two or more cushion material pieces having substantially the same shape divided in the circumferential direction, A propulsion pipe, wherein A ≧ B and A> C are satisfied, and each cushion material piece is a cushion material for a propulsion pipe whose both end faces are inclined surfaces. 3. The propulsion pipe according to claim 1, wherein the propulsion pipe cushion material satisfies A> B, and the outer peripheral surface is continuous from the outer peripheral edge of the first side surface toward the outer peripheral edge of the second side surface. A propulsion tube characterized by having an inclined surface. A cushion for a propulsion pipe, which is a plate member having at least a first side surface and a second side surface positioned substantially parallel to each other at a predetermined distance and an outer peripheral surface positioned on the outer peripheral edge of both side surfaces, and has a ring shape as a whole. Material,
A diameter (curvature radius) from the center of the ring to the outer peripheral edge of the first side surface is A, a diameter (curvature radius) from the outer periphery of the second side surface is B, and an arbitrary position in the axial direction of the outer peripheral surface When the diameter (curvature radius) up to C is C, A ≧ B and A> C, a propulsion tube cushion material,
The propulsion pipe cushion material is constituted by two or more cushion material pieces having substantially the same shape divided in the circumferential direction, and each cushion material piece satisfies the condition of A ≧ B and A> C. The cushion material for a propulsion pipe is characterized in that each of the cushion material pieces has inclined end surfaces on both sides . It is a cushioning material for propulsion pipes of Claim 4, Comprising: It is A> B, The said outer peripheral surface becomes the inclined surface which continued toward the outer peripheral edge of the 2nd side surface from the outer periphery of the 1st side surface. A propulsion tube cushioning material characterized by the above.

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