JP4330402B2 - Manhole block and manhole receiving frame installation structure using it - Google Patents

Description

  The present invention relates to a concrete manhole block mainly used for construction of a sewerage facility and a manhole receiving frame installation structure using the same.

  The manhole is a vertical hole connected to a sewer pipe in the ground or a horizontal hole for cable wiring, and a manhole cover is provided flush with the ground surface at the upper end of the vertical hole. The vertical hole is formed by a concrete manhole block, and a manhole receiving frame, usually made of cast iron, is fixed to the upper end of the manhole block, and the manhole cover is fixed in a state of being fitted into the tapered inner surface of the receiving frame.

  Such a manhole cover is heavy, and since it is fitted to the tapered inner surface of the receiving frame, it usually does not rattle or come off, but the pressure filled with gas or drainage filled in the manhole, or The manhole cover may come off the receiving frame due to mischief of outsiders. If the manhole cover is removed in this way, people or vehicles may fall into the manhole, or the cable in the side hole may be damaged. Or the lid | cover is not opened artificially (refer patent document 1).

On the other hand, the installation structure of the manhole receiving frame for receiving the manhole cover is usually a precast concrete manhole block, and the height adjustment arranged concentrically with the manhole block on the opening edge of the manhole block. It is comprised from the ring member and the manhole receiving frame arrange | positioned concentrically with the manhole bracket on this ring member. A plurality of anchor nuts are embedded in the top end surface of the opening edge of the manhole block, and anchor bolts screwed into the nuts are inserted into the flange portions of the manhole receiving frame, and the protruding ends of the anchor bolts The manhole receiving frame is fixed to the manhole block by tightening a lock nut screwed into the portion (see Patent Documents 2 and 3).
JP 2001-26938 A JP-A-9-296466 JP-A-10-121501

In the conventional manhole receiving frame installation structure, a plurality of anchor nuts are individually embedded in the opening edge of the manhole block, so the resistance to pulling upward is only the adhesion force of each anchor nut to the manhole block. It depends on the structure.
For this reason, for example, if there is an inflow of sewage exceeding the capacity of the sewerage facility due to rainfall that greatly exceeds the plan, the water pressure in the manhole will rise and the pressurized air staying in the pipeline will rise from below Due to the pressure, buoyancy exceeding the anchor bolt's adhesion force acts on the manhole receiving frame via the manhole cover and its locking device, and this causes so-called cone breakage in the concrete part around the anchor bolt, and the manhole receiving frame is Sometimes it floated upward and left the manhole block.

  In view of such conventional problems, the present invention significantly increases the pulling resistance upward of the manhole receiving frame, thereby reliably preventing the manhole receiving frame from being detached from the manhole block due to the pressure in the manhole. An object of the present invention is to provide a manhole block that can be used.

In order to achieve the above object, the present invention takes the following technical means.
That is, the manhole block according to the present invention is formed in a cylindrical block body (15) made of precast concrete having an opening edge that opens upward, and substantially the same planar shape as the opening edge of the block body (15). And an anchor frame (16) embedded in the opening edge thereof, and a plurality of anchor members (17) fixed at predetermined positions in the circumferential direction of the anchor frame (16) so that the screwing direction is aligned vertically. The anchor frame (16) has a cross-sectional width that can be inserted into the fresh concrete (31) from the top end surface (32) of the fresh concrete (31), and has a cross-sectional width over the entire circumference. top end surface of the opening edge portion of the entire circumference block body (15) with the same cross-sectional width is formed in an endless belt shape continuous with (10 Is characterized in the top end face (10) from being buried in the opening edge portion of the lower ring plate (18) made it from (34) so as not to be exposed from.

  The manhole receiving frame installation structure according to the present invention includes a manhole block having the above-described configuration, and a ring member for height adjustment arranged concentrically with the manhole block on the opening edge of the manhole block, A manhole receiving frame disposed concentrically with the manhole block on the ring member, and the manhole receiving frame is fixed to an anchor frame embedded in an opening edge of the manhole block. It is characterized by being fixed to the manhole block via an anchor member.

In this case, an anchor frame formed in substantially the same planar shape as the opening edge of the block body is embedded in the opening edge of the block body, and a plurality of anchor members are fixed at predetermined positions in the circumferential direction of the anchor frame. Therefore, when the entire inner circumference and outer circumference of the anchor frame adhere to the concrete, the upward pulling resistance is greatly increased.
For this reason, buoyancy that cannot be tolerated by the adhesive force of the anchor member alone is caused through the manhole cover and its locking device due to the pressure from below due to the rise of the water pressure in the manhole and the sudden rise of the pressurized air staying in the pipeline. Even if it acts on the manhole receiving frame, cone breakage does not occur in the concrete portion around the anchor member, and it is possible to prevent the manhole receiving frame from floating upward and coming off the manhole block.

Moreover, since it becomes easy to insert an anchor frame in the top end surface of fresh concrete at the time of manufacture of a manhole block, there exists an advantage that manufacture of the said block becomes easy. Further, in the present invention, if the anchor frame is embedded in the opening edge portion so as not to be exposed from the top edge surface of the opening edge portion of the block body, the concrete frame is more concrete than the case where the frame is exposed from the top edge surface. Since the contact area with respect to the surface increases and the adhesion is further improved, it is possible to more reliably prevent the manhole receiving frame from floating upward and detaching from the manhole block. In addition, if a large number of through-holes that penetrate the ring plate in the thickness direction are formed in the plate, the anchor frame can be more firmly attached to the block body than when there are no such through-holes. As a result, it is possible to more reliably prevent the manhole receiving frame from rising and separating from the manhole block.

  In addition, the anchor frame may be composed of a plurality of endless belt-shaped ring plates that are spaced apart from each other in the vertical direction and a plurality of rod-shaped members that connect the ring plates to each other. In this case, since a plurality of ring plates connected by a plurality of rod-shaped members are embedded in the block main body, the adhesion force of the anchor frame to the block main body is further increased compared to the case of a single ring plate. Thus, it is possible to more reliably prevent the manhole receiving frame from floating upward and detaching from the manhole block.

  As described above, according to the present invention, the upward pulling resistance of the manhole receiving frame can be increased, so that it is possible to reliably prevent the manhole receiving frame from being detached from the manhole block due to the pressure in the manhole. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 3 shows an installation structure of a manhole receiving frame using the manhole block of the present invention. As shown in the figure, the installation structure in this case constitutes the upper structure of manhole equipment as a sewerage facility. This manhole facility is constructed by stacking a plurality of manhole blocks concentrically up and down, and actually reaches several meters underground, and the bottom is closed with, for example, in-situ invert concrete. . A sewer pipe is connected to the lower part of the side wall of the manhole facility.

The installation structure of this embodiment includes a manhole block 1 made of precast concrete, a ring member 2 for height adjustment arranged concentrically with the block 1 on the opening edge of the block 1, and the ring member. 2 is provided with a manhole receiving frame 3 made of cast iron and arranged concentrically with the manhole block 1.
Among them, the manhole receiving frame 3 includes a fitting frame 5 formed in a circular short cylinder shape into which a manhole cover 4 made of cast iron is fitted, and a mounting flange projecting radially outward from the lower end of the fitting frame 5. 6 and a number of reinforcing ribs 7 (see FIG. 1) connecting between the outer peripheral surface of the frame 5 and the upper surface of the flange 5. An anchor bolt 8 described later is inserted into the mounting flange 6. Bolt insertion holes 9 (see FIG. 1) are formed. Although not shown, the manhole receiving frame 3 of the present embodiment is provided with a lock device that prevents the manhole cover 4 from being opened naturally or artificially.

The ring member 2 is made of precast concrete having a cross-sectional width equal to the opening edge of the manhole block 1 and formed in a circular ring shape in plan view, and is mounted on the top end surface 10 of the opening edge of the block 1. By being placed, it becomes a pedestal for adjusting the installation height of the manhole receiving frame 3. The ring member 2 includes an escape recess 11 that opens to the lower surface side to avoid interference with an anchor member 11 described later, and an anchor hole that communicates with the escape recess 11 and penetrates the cross section of the ring member 2. 13 is formed.
Although not shown in FIG. 3, a rubber spacer or adjustment mortar may be interposed between the ring member 2 and the manhole receiving frame 3. Moreover, you may decide to construct | assemble the said ring member 2 itself with the on-site strike early strong concrete.

  The manhole block 1 includes a cylindrical block body 15 made of precast concrete, an anchor frame 16 embedded in an opening edge of the block body 15, and a plurality of the anchor frames 16 fixed at predetermined positions in the circumferential direction of the anchor frame 16. The block main body 15 is formed into a concrete product by compacting the cemented concrete material while vibrating it and immediately demolding it to form a concrete product. It is manufactured by the mold method. Moreover, since the manhole block 1 of this embodiment is arrange | positioned in the uppermost part of a manhole installation, it is formed in the taper shape as the side wall of the block main body 15 goes upwards.

  As shown in FIG.1 and FIG.2, the anchor frame 15 consists of the single ring plate 18 formed in the endless belt by connecting the both ends of a long strip-shaped steel plate mutually by welding. However, the ring plate 18 may be made of cast iron or FRP. The anchor members 17 are fixed at three locations spaced apart at equal intervals in the circumferential direction of the ring plate 18. The ring plate 18 is formed with a large number of through holes 19 penetrating in the thickness direction at regular intervals, thereby further increasing the adhesion force to the block body 15.

  The anchor member 17 of the present embodiment is formed of a fixing nut into which the anchor bolt 8 can be screwed. Each fixing nut is formed on the upper edge of the ring plate 18 so that the screwing direction of the anchor bolt 8 is aligned vertically. It is fixed by welding. As shown in FIGS. 1 to 3, the anchor member 17 made of the fixing nut is fixed at an eccentric position so that the center hole portion is located outside the diameter of the ring plate 18. In addition, the anchor frame 16 is embedded substantially at the center in the width direction of the opening edge so that the upper end edge thereof coincides with the top end surface 10 of the opening edge of the block body 15. Is projected from the top end face 10 and exposed to the outside.

  In order to install the manhole receiving frame 3 flush with the road surface using the manhole block 1 having the above-described configuration, first, the ring member 2 is placed on the top end surface 10 of the opening edge of the block 1 and then the ring member. A manhole receiving frame 3 is placed on 2 and aligned with each other coaxially. Thereafter, the anchor bolt 8 is inserted into the bolt insertion hole 9 and the anchor hole 13 and the lower end portion thereof is screwed to the anchor member 17, and then the lock nut 21 is screwed to the upper end portion of the bolt 8 via the washer 20. The lock nut 21 may be tightened with a rotating tool (not shown).

At this time, according to the manhole block 1 of the present embodiment, the anchor frame 16 formed in substantially the same planar shape as the opening edge of the block main body 15 is embedded in the top end surface 10 of the opening edge of the block main body 15. Since a plurality of anchor members 17 are fixed at predetermined positions in the circumferential direction of the anchor frame 16, the entire inner and outer peripheral surfaces of the anchor frame 16 adhere to the concrete, thereby generating an upward pulling resistance.
For this reason, buoyancy that cannot be tolerated by the adhesion force of the anchor member 17 alone is caused by the pressure from below due to the rise of water pressure in the manhole or the sudden rise of the pressurized air staying in the pipe line. Even if it acts on the manhole receiving frame 3, the cone portion does not break in the concrete portion around the anchor member 17, and the manhole receiving frame 3 is lifted upward and separated from the manhole block 1 in advance. Can be prevented.

  Moreover, in the manhole block 1 of this embodiment, since the anchor frame 16 is comprised from the single ring plate 18 formed in the endless belt shape, the anchor frame 16 is made into fresh concrete at the time of manufacture of the manhole block 1 mentioned later. There is an advantage that the block 1 can be easily manufactured by being easily inserted into the top end surface 32 of the block 31. In addition, since a large number of through holes 19 that penetrate the ring plate 18 in the thickness direction are formed in the plate 18, the block body 15 can be compared with a case where such through holes 19 are not formed. There is also an advantage that the adhesion force of the anchor frame 16 is further increased, and the manhole receiving frame 3 can be more reliably prevented from floating upward and being detached from the manhole block 1.

4 and 5 show a method for manufacturing the manhole block 1 according to the present embodiment.
As shown in these drawings, the manhole block 1 of the present embodiment is manufactured by an immediate demolding method using a vibrating formwork device 23. In this case, the formwork device 23 is formed at the bottom of the pit 24. The base plate 26 placed on the vibration isolator 25, the inner mold frame 28 with the mounting flange 27 fixed on the plate 26, and the inner mold frame 28 so as to surround the outer periphery thereof. An outer mold frame 29 set on the flange 27 and a vibrator 30 housed in the inner mold frame 28 are provided.

  Then, as shown in FIG. 4, after a fresh slack 31 made of super sludge of zero slump is driven into a placement space formed between the inner mold frame 28 and the outer mold frame 29, the vibrator 30 is operated. As a result, the entire inner and outer molds 28 and 29 are vibrated at high speed to compact the concrete 31. After the compaction is completed, the anchor frame 16 is inserted and embedded in the top end face 32 of the fresh concrete 31 as shown in FIG. Thereafter, the fresh concrete 31 is immediately removed from the molds 28 and 29 and cured, whereby the molding of the manhole block 1 is completed.

As described above, according to the manufacturing method of the manhole block 1 of the present embodiment, the anchor frame 16 is directly inserted into the fresh concrete 31 after the vibration process is finished, so that the anchor frame 16 is positioned. This is advantageous in that the manhole block 1 can be easily manufactured at low cost.
FIG. 6 shows a modification of the anchor frame 16.
In this case, the anchor frame 16 includes a plurality of end plate-like (three in the illustrated example) ring plates 34 arranged at equal intervals in the vertical direction, and a plurality of ring plates 34 that connect the ring plates 34 to each other. It is comprised from the rod-shaped material 35 (three in the example of a figure).

  For this reason, when the anchor frame 16 according to such a modification is employed, a plurality of ring plates 34 connected by a plurality of rod-shaped members 35 are embedded in the block main body 15. Compared with the case where only the plate 18 is embedded (in the case of FIGS. 1 to 3), the adhesion force of the anchor frame 16 to the block body 15 is further increased, and the manhole receiving frame 3 is lifted upward and detached from the block body 15. It can prevent more reliably.

FIG. 7 shows another embodiment of the manhole block 1 according to the present invention.
In the manhole block 1 in this case, the anchor member 17 includes a long nut 36 that is long in the vertical direction. The long nut 36 has an opening in the block main body 15 so that the upper end thereof coincides with the top end surface 10 of the block main body 15. Embedded in the edge. And the lower end part of these long nuts 36 is being fixed to the upper end of the anchor frame 16 which consists of the ring plate 18 embed | buried comparatively deeply in the opening edge part by pin joining or welding.

  As described above, in another embodiment shown in FIG. 7, the anchor member 17 made of the long nut 36 is embedded in the opening edge of the block main body 15, and the anchor frame 16 that connects the long nuts 36 is opened. Since it is embedded in the opening edge so as not to be exposed from the top end face 10 of the edge, the contact area with respect to the concrete is increased and the adhesion is further improved as compared with the embodiment of FIG. 1 exposed from the top end face 10. As a result, the manhole receiving frame 3 can be more reliably prevented from floating upward and detaching from the manhole block 1.

In addition, the said embodiment is an illustration of this invention and does not restrict | limit the range. The scope of the present invention is defined by the claims, and all modifications within the scope equivalent to the configurations described therein are also included in the present invention.
For example, in the above embodiment, the anchor member 17 is constituted by a fixed nut or a long nut 36, but the anchor member 17 may be constituted by not only a nut but also a bolt.

It is an assembly perspective view which shows the attachment positional relationship of the manhole block and manhole receiving frame which concern on this invention. It is a perspective view of an anchor frame. It is sectional drawing which shows the installation structure of the manhole receiving frame which concerns on this invention. It is side surface sectional drawing of the formwork of the manhole block which concerns on this invention, and has shown the placing process of fresh concrete. It is side surface sectional drawing of the formwork of the manhole block which concerns on this invention, and has shown the embedding process of the anchor frame. It is a perspective view which shows the modification of an anchor frame. It is a perspective view which shows other embodiment of the manhole block which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manhole block 2 Ring member 10 Top end surface 15 Block main body 16 Anchor frame 17 Anchor member 18 Ring plate 19 Through-hole 34 Ring plate 35 Bar-shaped material

Claims (4)

A cylindrical block body (15) made of precast concrete having an opening edge opening upward;
An anchor frame (16) formed in substantially the same planar shape as the opening edge of the block body (15) and embedded in the opening edge;
A plurality of anchor members (17) fixed at predetermined positions in the circumferential direction of the anchor frame (16) so that the screwing direction is aligned vertically.
The anchor frame (16) has a cross-sectional width that can be inserted into the fresh concrete (31) from the top end surface (32) of the fresh concrete (31) and has the same cross- sectional width as the entire cross-section. It is formed in an endless belt shape having a continuous width, and the entire periphery is not exposed from the top end surface (10) of the opening edge portion of the block main body (15) on the opening edge portion below the top end surface (10). A manhole block comprising the embedded ring plates (18), (34).   The manhole block according to claim 2, wherein a number of through holes (19) penetrating the ring plate (18) in the thickness direction are formed in the plate (18). The anchor frame (16) includes a plurality of endless belt-shaped ring plates (34) arranged apart from each other in the vertical direction, and a plurality of rod-shaped members (35) that connect the ring plates (34) to each other. The manhole block according to claim 1, comprising: The manhole block (1) according to any one of claims 1 to 3, and a ring for height adjustment arranged concentrically with the manhole block (1) on an opening edge of the manhole block (1) A member (2) and a manhole receiving frame (3) disposed concentrically with the manhole block (1) on the ring member (2) are provided, and the manhole receiving frame (3) is the manhole block. A manhole receiver fixed to the manhole block (1) via a plurality of anchor members (17) fixed to an anchor frame (16) embedded in the opening edge of (1) Frame installation structure.

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