JP2006194033A - Manhole and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manhole which can easily be constructed and prevented from its float-up or sink-down due to ground liquefaction. <P>SOLUTION: A counterweight 27 is provided at a manhole 2, and the gross unit volume weight of the manhole 2 and the counterweight 16 is set up to be 1.1 or more and 1.3 or less. A float-up prevention block 43 is installed on a vinyl chloride tube 3, and the gross unit volume weight of the vinyl chloride tube 3 in a predetermined length and the float-up prevention block 43 is set up to be 1.1 or more and 1.3 or less. By such an easy work execution, the manhole 2 and vinyl chloride tube 3 can securely be prevented from float-up or sink-down due to ground liquefaction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a manhole apparatus including a manhole and a pipe connected to the manhole, and a construction method thereof.

2. Description of the Related Art Conventionally, when sewage is laid under a road on which vehicles pass, a manhole device for maintaining and managing the sewage is installed. Such a manhole device is provided with a substantially cylindrical manhole connected to a pipe forming a sewer. This manhole has a bottom slab which is arranged on the top of the Kuriishi foundation and becomes the foundation concrete, and a frame block, a straight wall and a slant wall connected to the pipe are sequentially provided on the top of the bottom slab (for example, (See Patent Document 1).
JP 2003-34940 A (page 3, FIG. 3)

  By the way, due to liquefaction of the ground at the time of an earthquake, manholes or pipes may float or sink at the backfill. And since such floating or sinking is more often seen in manhole devices with vinyl chloride pipes than manhole devices with steel pipes, the unit volume weight of the manhole and the unit volume weight for each predetermined length of the pipe are affected. Conceivable.

  In particular, manhole devices used for sewerage do not always collect sewage inside the manhole and pipes. Therefore, the unit volume weight of the manhole and the unit volume weight per predetermined length of the pipe are the material of the manhole and pipe itself. Therefore, the manhole device is desired to take further measures against liquefaction of the ground.

  This invention is made | formed in view of such a point, and it aims at providing the manhole apparatus which can be constructed easily, and can prevent the floating or subsidence with respect to the liquefaction of the ground, and its construction method.

  The manhole device according to claim 1 is provided in a manhole, a synthetic resin pipe connected to the manhole, and the manhole, and a total unit volume weight with the manhole is in a predetermined numerical range set in advance. The weight is set so that the total unit volume weight between the counterweight part set with the weight and the pipe provided for the predetermined length of the pipe is within the predetermined numerical range. And a pipe weight.

  Then, a counterweight portion is provided in the manhole so that the total unit volume weight with the manhole is in a predetermined numerical range, and the total unit volume weight with the pipe for each predetermined length of the pipe is a predetermined By providing piping weights in the piping so as to be in the numerical range, manholes and piping can be reliably prevented from rising or sinking due to liquefaction of the ground with easy construction.

  The manhole device according to claim 2 is provided with a manhole, a pipe connected to the manhole, and the manhole, and has a weight so that a total unit volume weight with the manhole falls within a predetermined numerical range. And a set counter weight portion.

  And by providing the counterweight part in the manhole so that the total unit volume weight with the manhole is within a predetermined numerical range, manholes and pipes can be lifted or subsided against liquefaction of the ground with easy construction. Make sure to prevent it.

  A manhole device according to a third aspect is the manhole device according to the first or second aspect, wherein the predetermined numerical range is from 1.1 to 1.3.

  And by making the predetermined numerical range 1.1 or more and 1.3 or less, the rising or sinking of manholes and pipes is more reliably prevented.

  The manhole device according to claim 4 is the manhole device according to any one of claims 1 to 3, wherein the counterweight portion is provided above a counterweight provided at a lower end portion of the manhole and the counterweight of the manhole. A reinforcing floor slab provided, and a connecting body for connecting the reinforcing floor slab and the counterweight are provided.

  A counterweight is provided at the lower end of the manhole, a reinforcing floor slab is provided above the counterweight, and the counterweight and the reinforcing floor slab are connected by a connecting body, so that the strength of attaching the counterweight to the manhole is increased. Can be reinforced.

  The construction method of the manhole apparatus according to claim 5 includes a manhole, a synthetic resin pipe connected to the manhole, a counterweight, a counterweight portion provided in the manhole, and the pipe. A construction method of a manhole apparatus comprising a weight for piping, wherein the counterweight made of precast concrete is attached to the manhole, and a predetermined unit volume weight of the manhole and the counterweight portion is set in advance. A pipe weight is attached to the pipe, and a total unit volume weight of the pipe and the pipe weight for each predetermined length of the pipe is set to the predetermined numerical range. It is set so as to be.

  Then, a precast concrete counterweight is attached to the manhole, the total unit volume weight of the manhole and the counterweight portion is set to be in a predetermined numerical range, and the pipe weight is attached to the pipe. By setting the total unit volume weight of the pipe and the pipe weight for each predetermined length of the pipe to be within a predetermined numerical range, the manhole and the pipe can be lifted or subsided against liquefaction of the ground. It is possible to easily construct a structure that reliably prevents the construction.

  The construction method for a manhole device according to claim 6 is a construction method for a manhole device comprising a manhole, a pipe connected to the manhole, a counterweight, and a counterweight portion provided in the manhole. The counterweight made of precast concrete is attached to the manhole, and the total unit volume weight of the manhole and the counterweight portion is set within a predetermined numerical range.

  Then, by attaching a precast concrete counterweight to the manhole and setting the total unit volume weight of the manhole and the counterweight portion to be within a predetermined numerical range set in advance, the manhole for ground liquefaction and It is possible to easily construct a new structure that reliably prevents the floating or sinking of piping.

  The construction method of the manhole device according to claim 7 is provided with a manhole, a synthetic resin pipe connected to the manhole, a counterweight, a counterweight portion provided in the manhole, and the pipe. A construction method of a manhole device comprising a weight for piping, wherein the counterweight is formed by hitting concrete around the manhole, and a total unit volume weight of the manhole and the counterweight portion is preset. The pipe weight is attached to the pipe, and the total unit volume weight of the pipe and the pipe weight for each predetermined length of the pipe is set to the predetermined numerical range. It is set to be in the numerical range.

  Then, concrete is struck around the manhole to form a counterweight, the total unit volume weight of the manhole and the counterweight part is set within a predetermined numerical range, and the pipe weight is attached to the pipe In addition, by setting the total unit volume weight of the pipe for each predetermined length and the weight for the pipe to be within a predetermined numerical range, It is possible to easily construct a structure that reliably prevents manholes and pipes from rising or sinking.

  The manhole device construction method according to claim 8 is a manhole device construction method comprising a manhole, a pipe connected to the manhole, a counterweight, and a counterweight portion provided in the manhole. The concrete weight is cast around the manhole to form the counterweight, and the total unit volume weight of the manhole and the counterweight portion is set within a predetermined numerical range.

  Then, concrete is cast around the manhole to form a counterweight, and the total unit volume weight of the manhole and the counterweight portion is set to be within a predetermined numerical range set in advance. On the other hand, it is possible to easily construct a structure that reliably prevents the manhole and piping from floating or sinking due to liquefaction of the ground.

  The construction method of the manhole device according to claim 9 is the construction method of the manhole device according to any one of claims 5 to 8, wherein the predetermined numerical range is 1.1 or more and 1.3 or less.

  And by making the predetermined numerical range 1.1 or more and 1.3 or less, the rising or sinking of manholes and pipes is more reliably prevented.

  The manhole device construction method according to claim 10 is the manhole device construction method according to any one of claims 5 to 9, wherein the counterweight portion is provided with a counterweight at a lower end portion of the manhole, and the counterweight of the manhole is provided. A reinforcing floor slab is provided on the upper side, and the reinforcing floor slab and the counterweight are connected by a connecting body.

  A counterweight is provided at the lower end of the manhole, a reinforcing floor slab is provided above the counterweight, and the counterweight and the reinforcing floor slab are connected by a connecting body, so that the strength of attaching the counterweight to the manhole is increased. Can be reinforced.

  According to the manhole device according to claim 1, the counterweight portion is provided in the manhole so that the total unit volume weight with the manhole falls within a predetermined numerical range, and the pipes are set for each predetermined length of the pipe. By providing piping weights so that the total unit volume weight falls within a predetermined numerical range, manholes and piping can be prevented from rising or sinking due to liquefaction of the ground with easy construction.

  According to the manhole device according to claim 2, by providing the counterweight portion in the manhole so that the total unit volume weight with the manhole falls within a predetermined numerical range, the liquefaction of the ground can be easily performed. Manholes and piping can be reliably prevented from rising or sinking.

  According to the manhole device according to claim 3, in addition to the effect of the manhole device according to claim 1 or 2, the predetermined numerical range is 1.1 or more and 1.3 or less, so Or settlement can be prevented more reliably.

  According to the manhole device of the fourth aspect, in addition to the effect of the manhole device according to any one of the first to third aspects, the counterweight is provided at the lower end portion of the manhole, and the reinforcing floor slab is provided above the counterweight. By providing and connecting the counterweight and the reinforcing floor slab with a connecting body, the strength of attaching the counterweight to the manhole can be reinforced.

  According to the construction method of the manhole device according to claim 5, the counterweight made of precast concrete is attached to the manhole so that the total unit volume weight of the manhole and the counterweight portion falls within a predetermined numerical range. By setting the pipe weight to the pipe and setting the total unit volume weight of the pipe for each predetermined length of the pipe and the pipe weight to be within the predetermined numerical range, It is possible to easily construct a new structure that reliably prevents the manhole and piping from rising or sinking against liquefaction.

  According to the construction method of the manhole device according to claim 6, the counterweight made of precast concrete is attached to the manhole so that the total unit volume weight of the manhole and the counterweight portion falls within a predetermined numerical range. By setting, it is possible to easily construct a new structure that reliably prevents the manhole and piping from floating or sinking against liquefaction of the ground.

  According to the construction method of the manhole device according to claim 7, the counterweight is formed by hitting concrete around the manhole, and the total unit volume weight of the manhole and the counterweight portion is within a predetermined numerical range set in advance. By setting the pipe weight to the pipe and setting the total unit volume weight of the pipe and the pipe weight for each predetermined length of the pipe to be within a predetermined numerical range, With respect to existing manholes and piping, it is possible to easily construct a structure that reliably prevents the manhole and piping from rising or sinking due to liquefaction of the ground.

  According to the construction method of the manhole device according to claim 8, the counterweight is formed by hitting concrete around the manhole, and the total unit volume weight of the manhole and the counterweight portion is within a predetermined numerical range set in advance. By setting in this way, it is possible to easily construct a structure that reliably prevents the manhole and piping from floating or sinking against the liquefaction of the ground with respect to the existing manhole and piping.

  According to the construction method of the manhole device according to claim 9, in addition to the effect of the construction method of the manhole device according to any one of claims 5 to 8, the predetermined numerical range is 1.1 to 1.3. This makes it possible to more reliably prevent the manhole and piping from rising or sinking.

  According to the manhole device construction method according to claim 10, in addition to the effect of the manhole device construction method according to any one of claims 5 to 9, a counterweight is provided at the lower end portion of the manhole. By providing a reinforcing floor slab on the upper side and connecting the counterweight and the reinforcing floor slab with a connecting body, the strength of attaching the counterweight to the manhole can be reinforced.

  The configuration of the first embodiment of the present invention will be described below with reference to the drawings.

  In FIG. 1, reference numeral 1 denotes a manhole device for maintaining and managing a sewer, for example. The manhole device 1 is connected to the manhole 2 which constitutes a sewer and a substantially cylindrical manhole 2 into which an operator can enter. Synthetic resin, for example, a vinyl chloride pipe 3 (hereinafter referred to as a vinyl chloride pipe 3) as a pipe made of vinyl chloride.

  The manhole 2 has a manhole body 5 made of, for example, precast concrete, and a manhole cover 6 that can be attached to and detached from the manhole body 5.

  The manhole body 5 is, for example, a so-called No. 1 manhole. As shown in FIGS. 1 to 3, as shown in FIGS. 1 to 3, a bottom plate 11 and a cylindrical housing block integrally provided on the bottom plate 11 and connected to the PVC pipe 3. 12, a cylindrical straight wall 13 integrally provided on the upper portion of the housing block 12, and a substantially cylindrical oblique wall integrally provided on the upper portion of the straight wall 13 with a manhole cover 6 detachably attached to the upper end thereof. The bottom plate 11, the casing block 12, the straight wall 13 and the inclined wall 14 are integrally connected in advance with each other in a liquid-tight manner. Further, a counterweight portion 16 made of precast concrete is integrally provided on the outer side of the manhole 2. In the manhole 2, a plurality of steps 17 used by the operator are sequentially provided at predetermined intervals in the vertical direction, and the lower end of the inside is not illustrated incline from one side to the other side. Invert is provided with concrete and mortar.

  The bottom plate 11 closes the lower end portion of the housing block 12, and is a circular plate body in plan view.

  The housing block 12 is provided substantially perpendicular to the bottom plate 11, and an inflow port 21 and an outflow port 22 are formed on both sides thereof. The inflow port 21 is located corresponding to the upper side of the invert slope, and the outflow port 22 is located corresponding to the lower side of the invert slope. The PVC pipe 3 is inserted into the inlet 21 and the outlet 22 in a liquid-tight manner.

  Further, the straight wall 13 is formed in a cylindrical shape having an outer diameter and an inner diameter substantially equal to those of the housing block 12, and is disposed coaxially and liquid-tightly on the upper portion of the housing block 12.

  The slant wall 14 is liquid-tightly connected at its lower end to the upper end of the straight wall 13 and is reduced in diameter so as to be eccentric to the right side as shown in FIG. 2 toward the upper end. An opening 25 is formed so that the lid 6 is detachable and an operator enters and exits.

  The counterweight portion 16 includes a counterweight 27 attached to a lower portion of the bottom plate 11 that is a lower end portion of the manhole 2, a reinforcing floor slab 28 attached to the periphery of the inclined wall 14 above the counterweight 27, A PC steel rod 29 is provided as a connecting body for connecting the counterweight 27 and the reinforcing floor slab 28 to each other.

  The counter weight 27 is disposed on the chestnut foundation 31 and serves as a foundation concrete that supports the manhole body 5, is made of precast concrete, and is formed in a rectangular shape wider than the bottom plate 11 in plan view. Further, the counterweight 27 has a total unit volume weight of the manhole 2 and the counterweight portion 16 in a predetermined numerical range, for example, 1.1 to 1.3, preferably 1.1 to less than 1.2. The weight is set.

  Furthermore, the reinforcing floor slab 28 is a plate body made of precast concrete and having a quadrangular shape in plan view, and a fitting hole 33 that fits to the outer surface of the inclined wall 14 is formed in a substantially central portion. The reinforcing floor slab 28 is formed to have a size substantially equal to that of the counterweight 27 in plan view, and is formed to be thinner than the counterweight 27.

  The PC steel rod 29 is corrosion-resistant, and as shown in FIG. 4, the lower end portion, which is one end portion, is inserted into the S insert 35 as a receiving member embedded in the upper four corners of the counterweight 27, respectively. As shown in FIG. 5, the upper end as the other end is inserted into the insertion holes 36 formed at the four corners of the reinforcing floor slab, and the reinforcing floor slab is held by the counterweight 27. The upper surface of 28 is held by a washer 38 and a nut 39.

  On the other hand, the manhole cover 6 is a plate formed in a circular shape in plan view with cast iron or the like, and is detachably attached to the opening 25 via a cover frame (not shown) provided in the opening 25.

  Furthermore, for example, a PVC pipe 3 having a diameter of 100 to 150 mm is used, and sewage passes therethrough. The PVC pipe 3 is provided with a floating prevention block 43 as a piping weight at every predetermined distance.

  These anti-floating blocks 43 are attached to the outer peripheral surface of the PVC pipe 3 so that the PVC pipe 3 is sandwiched from above and below by the block upper part 43a and the block lower part 43b. These anti-floating blocks 43 have a predetermined length that is the same as the total unit volume weight of the manhole 2 and the counterweight portion 16 in the predetermined length of the PVC pipe 3, for example, the PVC pipe 3 every 5 m. The weight is set to be within a range, that is, 1.1 to 1.3, preferably 1.1 to less than 1.2.

  Next, the construction method of the manhole device according to the first embodiment will be described with reference to FIGS.

  This construction method of the manhole device 1 is used when a manhole device 1 is newly installed. First, the manhole body 5 is assembled, and a counterweight 27 is disposed at the lower part of the manhole body 5. Reinforcement in which the lower end portion of the PC steel rod 29 is screwed into S inserts 35 provided at the four corners of 27, and the upper end portion of the PC steel rod 29 is fitted through the upper side of the manhole body 5 through the fitting hole 33. The manhole 2 is assembled in advance by being inserted into the insertion hole 36 of the floor slab 28 and fixed by a washer 38 and a nut 39.

  Further, the road surface GL at the installation position of the manhole 2 is excavated, and steel sheet piles (sheet piles) 46 are driven inside the excavated portion, and H-shaped steel 47 is squared inside these steel sheet piles 46 at, for example, two places at the top and bottom Assembling in a frame shape, the four corners of these H-shaped steels 47 are reinforced by reinforcing members 48 and earthed. Similarly, the road surface GL is excavated into a groove shape along the PVC pipe 3, and a steel sheet pile (not shown) is driven or a support work is performed.

  In this state, the chestnut foundation 31 is provided in the excavation part for the manhole 2, and abandoned concrete (not shown) is laid on the top of the chestnut foundation 31. Install.

  The PVC pipe 3 is inserted into the inlet 21 and the outlet 22 of the manhole body 5 to be connected in a liquid-tight manner, and the anti-floating block 43 is attached to the PVC pipe 3 every predetermined distance, and the steel sheet pile 46 is pulled out. And then backfill one after another while dismantling the dough.

  As described above, according to the first embodiment, the counterweight 27 made of precast concrete is attached to the manhole 2, and the total unit volume weight of the manhole 2 and the counterweight portion 16 is 1.1 or more. Is set to be 3 or less, preferably 1.1 or more and less than 1.2, and the levitating prevention block 43 is attached to the PVC pipe 3, and the total unit with the levitating prevention block 43 for each predetermined length of the PVC pipe 3 By setting the volume weight to be 1.1 or more and 1.3 or less, preferably 1.1 or more and less than 1.2, the manhole 2 and the PVC pipe 3 can be surely lifted or submerged against the ground liquefaction. Can be prevented.

  In particular, since the first embodiment is a manhole device 1 used for sewerage, the sewage is not always stored inside, and the unit volume weight is determined substantially depending on the material of the manhole and the pipe. Since it does not become too large, the unit volume weight of the manhole device 1 can be easily secured by setting as described above.

  In addition, when the manhole device 1 is newly set up, the counterweight 27 is made of precast concrete, so that the construction becomes easier than the case where the counterweight is made of cast-in-place concrete.

  Furthermore, the strength of attaching the counterweight 27 to the manhole 2 can be reinforced by connecting the counterweight 27 and the reinforcing floor slab 28 with the PC steel rod 29.

  Then, the levitation prevention block 43 can be easily attached to the PVC pipe 3 by forming the levitation prevention block 43 so as to sandwich the PVC pipe 3 between the block upper portion 43a and the block lower portion 43b.

  Next, a second embodiment will be described with reference to FIGS. In addition, about the structure and effect | action similar to said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the embodiment shown in FIGS. 8 to 10, the counterweight 27 is provided integrally with the bottom slab 11 of the manhole body 5 by spot cast concrete.

  That is, in the embodiment shown in FIGS. 8 to 10, the counterweight 27 and the anti-floating block 43 are provided for the existing manhole device 1, and first, the manhole 2 and the PVC pipe of the existing manhole device 1 are provided. The road surface GL corresponding to 3 is excavated and earth retaining is performed, the reinforcing bars 49 are protruded from the bottom plate 11, a mold frame (not shown) is arranged around the bottom plate 11, and concrete is hit to form the counterweight 27.

  Further, the reinforcing floor slab 28 is attached to the manhole body 5 and the counterweight 27 and the reinforcing floor slab 28 are connected and fixed by the PC steel rod 29.

  And by constructing in this way, it is possible to achieve the same effects as the first embodiment, and when constructing the existing manhole device 1, precast concrete is provided below the manhole. Construction is easier than installing a counterweight made of metal.

  In the second embodiment, when the counterweight 27 is formed, it is not always necessary to form the counterweight 27 at the position of the bottom plate 11 if it is integrally formed around the manhole body 5.

  In the above embodiments, the shapes of the counterweight 27 and the reinforcing floor slab 28 are not limited to the above-described configuration.

  Furthermore, if the unit volume weight with respect to the vinyl chloride pipe 3 for every predetermined length of the vinyl chloride pipe 3 can be set to a predetermined numerical range, the position where the vinyl chloride pipe 3 is attached is not limited to the above configuration. .

  As the pipe, a resin pipe other than the vinyl chloride pipe 3 made of vinyl chloride can be selected. In this case, the weight and arrangement position of the anti-floating block 43 are set according to the material of the synthetic resin.

  Further, a configuration and construction method in which the counterweight portion 16 of each of the above embodiments is provided for a manhole apparatus having a pipe other than that made of synthetic resin is also possible. Also in this case, the same effects as those of the above embodiments can be achieved.

It is a front view which shows the manhole apparatus of the 1st Embodiment of this invention. It is a side view which shows a manhole apparatus same as the above. It is the top view which notched a part of reinforcement floor slab of the manhole apparatus same as the above. It is side surface sectional drawing which expands and shows a part of manhole apparatus same as the above. It is side surface sectional drawing which expands and shows another part of manhole apparatus same as the above. It is a top view which shows the construction method of a manhole apparatus same as the above. It is AA sectional drawing of FIG. 6 which shows the construction method of a manhole apparatus same as the above. It is a front view which shows the manhole apparatus of the 2nd Embodiment of this invention. It is a side view which shows a manhole apparatus same as the above. It is the top view which notched a part of reinforcement floor slab of the manhole apparatus same as the above.

Explanation of symbols

1 Manhole device 2 Manhole 3 Vinyl chloride pipe as piping
16 Counterweight section
27 Counterweight
28 Reinforced floor slab
29 PC steel bar as a connecting body
43 Anti-floating block as piping weight

Claims (10)

With manholes,
Synthetic resin piping connected to this manhole,
A counterweight portion provided in the manhole, and having a weight set so that the total unit volume weight with the manhole falls within a predetermined numerical range,
A weight for a pipe provided in the pipe and having a weight set so that a total unit volume weight with the pipe for each predetermined length of the pipe is in the predetermined numerical range. Manhole device. With manholes,
Piping connected to this manhole,
And a counterweight portion, the weight of which is set in the manhole and set so that the total unit volume weight with the manhole falls within a predetermined numerical range. The manhole device according to claim 1 or 2, wherein the predetermined numerical range is 1.1 or more and 1.3 or less. The counterweight part
A counterweight provided at the lower end of the manhole,
A reinforced slab provided above the counterweight of the manhole;
The manhole device according to any one of claims 1 to 3, further comprising a connecting body that connects the reinforcing floor slab and the counterweight. With manholes,
Synthetic resin piping connected to this manhole,
A counterweight, and a counterweight portion provided in the manhole;
It is a construction method of a manhole device equipped with a weight for piping provided in the piping,
Attach the counterweight made of precast concrete to the manhole, and set so that the total unit volume weight of the manhole and the counterweight portion falls within a predetermined numerical range,
A pipe weight is attached to the pipe, and a total unit volume weight of the pipe and the pipe weight for each predetermined length of the pipe is set within the predetermined numerical range. Construction method of the manhole device that was done. With manholes,
Piping connected to this manhole,
A manhole apparatus construction method comprising a counterweight and a counterweight portion provided in the manhole,
The counterweight made of precast concrete is attached to the manhole, and the total unit volume weight of the manhole and the counterweight portion is set to be in a predetermined numerical range set in advance. Construction method. With manholes,
Synthetic resin piping connected to this manhole,
A counterweight, and a counterweight portion provided in the manhole;
It is a construction method of a manhole device equipped with a weight for piping provided in the piping,
Concrete is cast around the manhole to form the counterweight, and the total unit volume weight of the manhole and the counterweight portion is set to be within a predetermined numerical range,
A pipe weight is attached to the pipe, and a total unit volume weight of the pipe and the pipe weight for each predetermined length of the pipe is set within the predetermined numerical range. Construction method of the manhole device that was done. With manholes,
Piping connected to this manhole,
A manhole apparatus construction method comprising a counterweight and a counterweight section provided in the manhole,
Concrete is formed around the manhole to form the counterweight, and the total unit volume weight of the manhole and the counterweight portion is set to be within a predetermined numerical range set in advance. Manhole device construction method. The method for constructing a manhole device according to any one of claims 5 to 8, wherein the predetermined numerical range is 1.1 or more and 1.3 or less. The counterweight part
A counterweight is provided at the lower end of the manhole,
A reinforcing floor slab is provided above the counterweight of the manhole,
The method for constructing a manhole apparatus according to any one of claims 5 to 9, wherein the reinforcing floor slab and the counterweight are connected by a connecting body.

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