JP4776569B2 - Manhole installation stabilization structure - Google Patents

Description

  The present invention relates to a manhole installation stabilization structure, and more particularly, to a manhole installation stabilization structure for preventing an unnecessary rise of a manhole embedded in the ground.

  In general, the manhole is provided for people to enter and exit for inspection, repair, cleaning, etc. of the sewer pipe, and is installed, for example, at a predetermined location of the sewer main. As for the installation method of such manholes, at the beginning of the installation of the sewer main, concrete is placed in the excavated installation site as a whole to form an integrated structure, or multiple concrete parts manufactured at the factory are used. There are those that are stacked and fixed to construct the entire shape of the manhole.

  FIGS. 10 and 11 show an example of such a manhole structure. As shown in FIG. 10, the manhole 10 is embedded in the ground 100 in an upright state, and the water inlet side is located at the lowest position. The sewer main 12a is connected to the drain side sewer main 12b. FIG. 11 shows the internal shape of the bottom 10a of the manhole 10. As shown in the figure, the bottom 10a has water flowing from the water supply side sewer main 12a to the water discharge side sewer main 12b. An invert 10b, which is a groove for smoothing the flow, is formed.

  Such a manhole 10 has a bottomed structure as described above, and the installation state in the ground is performed with a gap between the ground and the ground filled with crushed stone or sand. Moreover, in order to make the bottom part 10a of the manhole 10 into an appropriate surface state, first, gravel and mortar are laid, and the bottom part of the manhole 10 is formed thereon. In the state where such a bottomed manhole 10 is embedded in the ground 100, for example, when the ground 100 is liquefied by some vibration, buoyancy is generated and tends to rise. In particular, in the case of a large vibration such as an earthquake, the surrounding ground 100 is seriously liquefied, and the rise of the manhole 10 is difficult to overlook.

  FIG. 12 shows the manhole 10 protruding to the ground caused by the liquefaction of the ground 100. As shown in the figure, it protrudes to the ground surface so as to break through the surface of the ground 100, and it becomes a situation that hinders the movement and running of people and vehicles, which becomes a particularly serious problem in the case of an earthquake that requires retreat activity. Moreover, there exists a possibility that the coupling | bonding state with a sewer pipe may be destroyed by the raise of the manhole 10. FIG.

  As a technique for preventing such a protruding state to the ground surface, for example, it is disclosed in Patent Document 1, and the anchor member (20) is projected so as to project around the manhole at the upper end portion of the manhole pipe (10). The anchor member (20) is embedded in the pavement C portion on the surface of the ground. And it is made to resist the force which pushes up a manhole pipe (10) with the fixed intensity | strength to the pavement C part of this anchor member (20).

  Patent Document 2 shows another example. In this technique, a hole is drilled from the bottom of the manhole to the non-liquefied layer of the ground below, and an anchor tension member is inserted into the hole. A method for injecting grout to fix the lower end of the anchor tension member to the non-liquefied layer is disclosed. The upper end of the anchor tension member is fixed to a pressure receiving plate (12) installed in the bottom of the manhole. The pressure receiving plate 12 disperses the lifting pressure generated by the anchor tensile material.

JP-A-8-165671 JP-A-2005-24896

  In the technique of Patent Document 1, an anchor member that extends around the upper end of the manhole is provided. Therefore, a relatively wide range of additional work or repair work is required for the pavement portion of the ground surface. Become. In addition, in the event of an earthquake, cracks and destruction occur in the pavement area on the ground surface, so when anchor members are installed in the pavement area, if the pavement area is destroyed, the manhole rises. It is also predicted that the prevention function cannot be sufficiently achieved.

  Moreover, in patent document 2, since an anchor tension | tensile_strength material is inserted to a non-liquefaction layer, the ensuring function of the deterrence by this is exhibited. However, in order to prevent a concentrated pulling force from being applied to the bottom of the manhole and to cause punching shear failure, a pressure receiving plate is installed in a relatively wide range at the bottom of the manhole. That is, a pressure receiving plate is provided that extends all the way to the vicinity of the inner peripheral wall at the bottom of the manhole. The application of tensile force to the pressure plate concentrates on the central opening of the pressure plate, which is the anchor tension material fixing part. Therefore, the pressure plate needs to have high rigidity, and is a material with sufficient thickness and strength. Must be secured. Therefore, the weight of the pressure receiving plate increases, resulting in an increase in installation cost and complication of installation work. In addition, as described above, the installation of the pressure receiving plate that extends around the entire bottom surface is difficult to secure a place where the worker stands in the manhole, assuming that the actual construction work in the manhole is assumed. Will be accompanied by difficulties.

  Furthermore, in the disclosed embodiment, consideration is not given to the presence of a groove called an invert that is usually formed at the bottom of a manhole, and in actual practice, the flow of sewage flowing in the groove. In other words, it is necessary to make the entire bottom part thinner, and conversely, the strength may be lowered.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent an accurate manhole from being lifted while preventing concentration of a pulling force in a narrow area of the manhole bottom with a simple and small configuration. It is to provide a manhole installation stabilization structure.

In order to achieve the above object, the manhole installation stabilization structure according to claim 1 is:
In the manhole installation stabilization structure, the manhole installed in the ground is pulled and fixed by installing an anchor member having a length reaching the depth to the firm stable ground below the manhole at the bottom of the manhole. A central concave portion of a predetermined depth formed in a truncated cone shape having a gradually decreasing diameter from the bottom surface toward the lower portion at the substantially central portion of the bottom portion, and an anchor member formed through the substantially central portion of the bottom portion of the central concave portion. A through-hole for insertion, an outer shape of a truncated cone shape that can be installed in a state where its outer periphery is in close contact with the central concave portion, an inner concave portion that opens to the bottom surface side of the truncated cone, and substantially the upper surface portion of the truncated cone A cone member formed of a rigid material having a through-hole through which the anchor member formed to penetrate in a central position is inserted, and an installation state of the anchor member The upper end portion of the anchor hole is inserted into the through hole of the bottom portion of the manhole and the through hole of the cone member mounted in the central recess, and at least the anchor member is locked so as to restrain the upward movement of the bottom portion of the manhole. And a locking and fixing means.

  According to the above configuration, in the state where the lower end of the anchor member is fixed at a depth up to a firm solid ground below, when the force in the direction of rising to the manhole is applied, the tensile force of the anchor member is the locking and fixing means. To be added to the cone member. Since the cone member is in close contact with the frustoconical central concave portion whose shape decreases downward, the tensile force is received by the inclined inner surface (tapered surface) of the central concave portion. Therefore, the force that causes the manhole to rise is received as a force oblique to the vertical direction on the tapered surface of the central recess through the cone member. Therefore, since the force on the manhole bottom is distributed as an oblique force and in the circumferential direction, it is possible to prevent the tensile force from being concentrated on one portion of the manhole bottom. Accordingly, since the force is dispersed by the cone member having a relatively small shape, the manhole installation stabilization structure can be easily configured without a large installation work.

The manhole installation stabilization structure according to claim 2 is:
The plate has a rigid plate laid on the bottom of the manhole in a range covering a predetermined area around the central concave portion, and the cone member is installed in the central concave portion so that at least the upper end portion extends from the central concave portion. After the plate body is laid on the bottom of the manhole, the load of the cone member is dispersed in the central recess and the plate body when the cone member is immersed in the central recess. It is characterized by being configured to hang.

  As described above, basically, the tensile force is distributed from the cone member to the central concave portion. However, by installing the plate body, the effective distribution of the tensile force can be further achieved. In addition, since the plate body is an additional and auxiliary tensile force dispersion means for the cone member and the central recess, it does not have to be a wide area of the bottom area of the manhole, and the anchor member is fixed and fixed. Since no force is intensively applied to the part, the entire structure can be made thin.

The manhole installation stabilization structure according to claim 3 is:
The area where the plate body is installed at the bottom of the manhole is a tapered bottom formed so that the surface position gradually decreases from the inner wall side of the manhole to the center of the manhole bottom. The anchor member is locked by the locking and fixing means in the inner concave portion of the cone member, and then concrete is placed on the tapered bottom portion so as to have the same surface height as the other region of the manhole bottom portion. It is characterized by that.

  With this configuration, the tensile force from the anchor member transmitted to the plate body via the cone member is applied to the taper bottom. Accordingly, the force can be distributed over a wider range than when a tensile force is directly applied to the horizontal bottom surface.

The manhole installation stabilization structure according to claim 4 is:
The plate body extends at least partially from the periphery of the central recess to a predetermined height of the inner wall of the manhole, and is fixed to the manhole at a portion extending to the inner wall of the manhole.

  According to this configuration, the tensile force of the anchor member added to the cone member is transmitted from the cone member and the plate body to the side wall of the manhole to which the extension portion is fixed, and the dispersion of the tensile force on the manhole by the anchor member is distributed. It is performed over a wide area and concentration of force is avoided. In particular, since the tensile force is dispersed not only at the bottom of the manhole but also at the side wall, the bottom of the manhole can be effectively prevented from being destroyed when a large levitating force is applied to the manhole.

The manhole installation stabilization structure according to claim 5 is:
The plate body is installed so as to extend in a direction connecting an upstream sewage pipe coupled to the manhole and a downstream sewage pipe, and the front and rear ends in the extending direction are respectively upstream from the manhole. It further extends in the direction of the sewage pipe and the downstream sewage pipe, and each extends on the bottom of the sewage pipe.

  According to this configuration, the tensile force of the anchor member added to the cone member is transmitted from the cone member and the plate body to the sewage pipes on both the upstream and downstream sides, and the dispersion of the tensile force on the manhole by the anchor member is wide. To avoid force concentration. In particular, by adding not only to the bottom of the manhole but also to the sewer pipe, destruction of the bottom when a large levitating force is applied to the manhole can be prevented more effectively.

  In addition, it is possible to always match the vertical position of the manhole in the vertical direction with the vertical position of the sewer pipe coupled thereto, and it is possible to effectively prevent the occurrence of gaps due to mutual positional deviation in the vertical direction. .

The manhole installation stabilization structure according to claim 6 is:
The cone member is provided with a lid member that closes the inner concave portion, and in a state where the anchor member is fixed, the antirust agent is injected into the inner concave portion of the cone member, and the antirust agent injection portion is It is closed with a lid member, and concrete is placed on the taper bottom in this state. By this structure, the rust prevention of the part to which the anchor member is fixed becomes accurate, and long-term stabilization of the installation state of the anchor member is achieved.

The manhole installation stabilization structure according to claim 7 is:
Sealing means for ensuring watertightness between the anchor member and the through hole of the cone member and the through hole at the bottom of the manhole is provided. This effectively prevents groundwater from entering the through-hole through which the anchor member of the cone member is inserted from the outside of the manhole bottom. Therefore, when the cone member is made of metal, it is possible to accurately prevent rust and the like due to water intrusion from below the bottom of the manhole.

  According to the present invention, the tensile force is distributed and transmitted from the anchor member to the cone member, and further to the additional and auxiliary members, so that the tensile force can be concentrated in a narrow range at the bottom of the manhole with a simple and small configuration. Can be effectively prevented. As a result, the manhole can be prevented from rising to the ground surface due to various factors such as earthquakes and ground deformation, and the installation of facilities for preventing the manhole from rising can be promoted.

  Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 1 shows a state where a manhole installation stabilizing structure according to an embodiment of the present invention is applied to a manhole 10 installed on the ground 100. As shown in the figure, the manhole 10 is provided with a manhole cover 14 attached to an opening 10 c that is the upper end of the manhole 10 so that the upper end surface of the opening 10 c is substantially flush with the upper end surface of the ground 100. An anchor member 16 is fixed to the bottom portion 10a of the manhole 10, and the lower end portion of the anchor member 16 extends to a stable formation below the ground (a formation that does not liquefy during any earthquake). Grout material is injected around and fixed firmly.

  FIG. 2 shows the structure of the manhole bottom 10a on which the manhole installation stabilizing structure according to the embodiment is installed. In the present embodiment, as shown in the figure, the installation groove 18 is formed with a predetermined width in a direction substantially perpendicular to the extending direction of the invert 10b described in FIG. FIG. 3 shows a situation when the manhole bottom 10a is viewed from above, and it is understood that the installation groove 18 is formed so as to be substantially orthogonal to the invert 10b as shown. When the application of the present invention is applied to the existing manhole 10 later, the installation groove 18 is formed by a lifting operation.

  A central recess 20 having a circular opening is formed in the center of the installation groove 18. The central recess 20 is formed as a truncated cone-shaped space whose shape gradually decreases downward in the figure. Further, a through hole 22 through which the anchor member 16 is inserted is formed further below. In addition, the minute level | step difference 24 formed between the center recessed part 20 and the through-hole 22 is a packing installation part in the case of installing the packing mentioned later, for example. When the later-described cone member 26, the threaded portion of the anchor member 16, and the anchor plate 30 and the nut 32 are made of a material having excellent rust resistance, this packing is not necessarily required. Is not provided.

  FIG. 4 shows the installation structure according to the first embodiment, and shows the fixing structure of the anchor member 16 in the central recess 20 and the surrounding structure in an enlarged manner. First, as shown in the figure, a cone member 26 having a frustoconical outer shape is fitted into the central recess 20. In other words, the cone member 26 is configured to have an outer shape that can substantially contact the inner shape of the central recess 20.

  FIG. 5 shows the cone member 26. As shown in FIG. 5, the cone member 26 has an inner recess 26a that opens to a portion that contacts the bottom surface of the truncated cone. The depth of the inner recess 26a is understood from FIG. In this way, the upper wall portion is formed so as to remain as much as the side wall of the cone member 26. And the through-hole 26c is formed in the wall part of the lower side in the installation state, ie, the upper surface part 26b of a truncated cone. The material of the cone member 26 is made of a highly rigid metal or resin. In the present embodiment, an example is shown in which the cone member 26 is loaded with a packing 28 formed of a resilient member such as rubber, resin, urethane, or the like for preventing entry of groundwater from the outside. ing.

  The upper end portion 16a of the anchor member 16 is inserted into the through hole 22 of the manhole bottom portion 10a, the through hole 28a of the packing 28, and the through hole 26c of the cone member 26, and the tip portion thereof is inserted into the inner recess 26a of the cone member 26. It is protruding. The protruding portion is provided with an anchor plate 30 and a nut 32 for fixing the anchor plate 30 to the anchor member 16.

  FIG. 6 shows another embodiment of the fixing portion of the anchor member 16, and a ring-shaped protrusion 30a is provided on the lower surface in the installed state of the anchor plate 30 as shown in the figure. The projection 30 a is configured to enter the through hole 26 c of the cone member 26. As a result, the packing 28 is pushed downward, the pressing force of the packing 28 is increased, and the waterproof property can be improved. Further, in this embodiment, the packing 28 is formed in a cylindrical shape, and the above-described minute step portion 24 is loaded with, for example, a flat plate ring 31 formed of resin so that the packing 28 is suppressed from below. Yes.

  The procedure for applying the installation structure according to the above-described embodiment to the existing manhole 10 is, for example, that the installation groove 18 and the through hole 22 are first formed by a lifting operation on the bottom of the manhole 10, and then the penetration is made. Begin by installing the anchor member 16 through the hole 22. The installation of the anchor member 16 is the same as in the known technology, and the outer diameter of the anchor member 16 is, for example, twice the outer diameter of the anchor member 16 depending on the situation by boring so as to reach a stable region where liquefaction of the ground does not occur easily. An insertion hole 17 having a four times inner diameter is formed, an anchor member 16 is inserted into the insertion hole 17, and a material 19 that is time-curable such as a grout material is injected into the insertion hole 17. And the fixation operation | work to the ground of the anchor member 16 is complete | finished by hardening of grout material.

  Then, if necessary, the cone member 26 loaded with the packing 28 is fitted into the central recess 20 while passing the upper end portion 16a of the anchor member 16 through the through hole 26c. In this state, the anchor plate 30 and the nut 32 are attached. Finally, concrete or the like is placed in the installation groove 18 while securing the concave groove shape of the invert 10b, and the installation is completed.

  In this installation state, when buoyancy acts on the manhole 10 due to ground liquefaction due to an earthquake or the like and an upward force is applied, the anchor member 16 is firmly fixed to the stable ground. 16 does not rise in the ground direction. The bottom 10 a of the manhole 10 is locked and fixed to the anchor member 16 via the cone member 16 by the anchor plate 30 and the nut 32. Therefore, the manhole 10 does not move up due to its buoyancy.

  At this time, a pulling force in the vertical direction from the anchor member 16 acts on the cone member 26, but the outer surface of the cone member 26 has a truncated cone shape with the upper surface portion down, A pressing force is applied to the inner side surface of the central recess 20 having the side surface from an oblique direction, and the tensile force of the anchor member 16 is dispersed. That is, since the vertical pulling force of the anchor member 16 is changed in direction by the inclined surface of the cone member 26, it is avoided that a force concentrated on the manhole bottom portion 10a is applied, and the manhole bottom portion 10a is prevented from being broken.

  FIG. 7 shows another embodiment, and the same elements as those in the embodiment shown in FIG. In the present embodiment, the plate body 34 is installed on the surface of the bottom of the installation groove 18 in a surface contact state. FIG. 8 shows the overall configuration of the plate body 34. As shown in the figure, the plate body 34 is formed of a flat plate having a shape corresponding to the shape of the bottom surface of the installation groove 18, and is substantially bent, for example. It is composed of a metal plate or resin plate with no strong rigidity. An opening 34a is formed in the central portion which is a position corresponding to the central concave portion 20 of the manhole bottom portion 10a in the installed state. The diameter of the opening 34a is substantially the same size as the inner diameter of the uppermost portion of the central recess 20, and in the state where the cone member 26 is installed immersingly, the load is applied to the plate body 34 from the outer surface of the cone member 26. It becomes a situation.

  Further, both ends of the plate body 34 are provided with attachment portions 34b bent upward, and the attachment portions 34b are in contact with the inner wall of the manhole 10 in the installed state. Therefore, the portion of the attachment portion 34b can be fixed to the inner wall of the manhole 10, and can be fixed with, for example, a bolt. By such attachment of the plate body 34, the tensile force transmitted from the anchor member 16 to the plate body 34 via the cone member 26 is distributed and transmitted from the attachment portion 34 b of the plate body 34 to the side wall of the manhole 10. Is done. Therefore, the pulling force applied to the manhole bottom 10a is reduced, and the function of preventing the destruction of the manhole bottom 10a is further improved.

  Further, a lid receiving portion 26d into which the lid portion 36 is fitted is formed on the inner side surface of the cone member 26, and is closed by the lid portion 36 in a state where the cone member 26 is filled with an oil-based substance such as grease. The As in the case of the embodiment shown in FIG. 4, concrete is placed in the installation groove 18 so as not to damage the continuous shape of the invar and 10b, and the cone member 26 and the plate body 34 are placed. Is embedded in the concrete, leaving only the attachment portion 34b.

  According to another embodiment of the above configuration, in addition to the distribution of the pulling force of the anchor member 16 by the cone member 26, the pulling force to the manhole bottom 10a by the plate body 34 can be distributed. Furthermore, the presence of the attachment portion 34b also distributes the pulling force to the upright manhole side wall, so that the manhole bottom 10a is more reliably protected against the pulling force from the anchor member 16, and as a result. The function of preventing the manhole 10 from being lifted by the anchor member 16 becomes more stable. Moreover, since the filling state of the oil-based substance into the cone member 26 is maintained for a long time due to the presence of the packing 28, the antirust function of the upper end portion of the anchor member 16 can be continuously secured.

  FIG. 9 shows still another embodiment, and shows an example in which a plate body 36 having a configuration different from that of the plate body 34 shown in FIGS. 7 and 8 is installed at different installation positions. In addition, the same code | symbol is attached | subjected to the element similar to the said embodiment, and the description is abbreviate | omitted.

  Although it is the same that the plate body 36 is configured in a plate shape, the installation direction is not the direction orthogonal to the invert 10b as shown in FIG. 3, but the same direction as the extension direction of the invert 10b. . That is, an installation groove 37 extending in the extending direction of the invert 10b is formed at a position slightly lower than the invert 10b portion, and the plate-like plate body 36 is installed there. What is characteristic is that both ends of the plate body 36 in the extending direction extend to the inside of the upstream sewer main 12 a and the downstream sewer main 12 b coupled to the manhole 10. That is, both end portions 36a of the plate body 36 extend on the bottoms of the sewer main pipe 12a and the sewer main pipe 12b, respectively.

  The cone member 26 added to this state and the anchor member 16 fixed to the cone member 26 are the same as those shown in FIGS. 4 and 7. Therefore, when buoyancy is added to the manhole 10, the anchor member 16 by the cone member 26 is used. In addition to the distribution of the pulling force, it is possible to distribute the pulling force to the bottom of the sewer main 12 by the plate body 36. As a result, concentration of force from the anchor member 16 to a narrow range on the manhole bottom portion 10a is avoided, and stabilization of the function of preventing the manhole 10 from being lifted by the anchor member 16 is achieved.

  In addition, this invention is not limited to the structure which concerns on the said embodiment, A various deformation | transformation is possible within the range of the summary of invention. For example, the size and shape of the inner recess 26a formed in the cone member 26 are not necessarily limited to the truncated cone shape shown in the figure, and can take various forms. If the outer shape of the cone member 26 is at least a truncated cone shape so that the entire inner surface of the central recess 20 can come into surface contact, the inner recess 26a secures a space for locking and fixing the upper end of the anchor member 16. It will be enough if it is done. Moreover, although the manhole bottom part in which the invert 10b was formed was illustrated in each said embodiment, this invention is applicable also to the manhole in which the invert 10b is not provided.

It is a schematic explanatory drawing which shows the state of the manhole of the state to which the manhole installation stabilization structure which concerns on embodiment was applied. It is explanatory drawing which shows the structure of the manhole bottom part to which the manhole installation stabilization structure which concerns on embodiment is applied. It is a schematic explanatory drawing which shows the shape seen from the upper direction of embodiment shown in FIG. It is explanatory drawing which shows the structure of the principal part of the manhole installation stabilization structure which concerns on embodiment. It is a structure explanatory drawing of the cone member used for embodiment of FIG. It is explanatory drawing of other embodiment of the fixing | fixed part of an anchor member. It is explanatory drawing which shows the structure of the principal part of the manhole installation stabilization structure which concerns on other embodiment. It is a structure explanatory view of the plate body used for the embodiment of FIG. It is a structure and installation state explanatory drawing which show other embodiment of a plate body. It is explanatory drawing which shows the installation state of a general manhole. It is explanatory drawing which shows the structure of the bottom part of a general manhole. It is explanatory drawing which shows the state which the manhole protruded on the ground surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Manhole 10a Manhole bottom part 12 Sewer main pipe 16 Anchor member 18 Installation groove 20 Central recessed part 22 Through-hole 26 Cone member 26a Inner recessed part 28 Packing 30 Receiving ring 32 Nut 34, 36 Plate body

Claims (7)

In the manhole installation stabilization structure that pulls and fixes the manhole installed in the ground by installing an anchor member having a length that reaches the depth to the firm stable ground below the manhole at the bottom of the manhole,
A central concave portion of a predetermined depth formed in a truncated cone shape with a gradually decreasing diameter from the bottom surface toward the lower side at the substantially central portion of the manhole bottom;
A through hole for inserting an anchor member formed in a substantially central portion of the bottom of the central recess,
The frustoconical outer shape that can be immersed and installed in a state where the outer periphery thereof is in close contact with the central recess, the inner recess that opens to the bottom surface side of the truncated cone, and the through hole formed substantially at the center position of the upper surface of the truncated cone A cone member formed of a rigid material having a through hole for inserting the anchor member;
In the state where the upper end portion of the anchor member is installed is inserted into the through hole of the manhole bottom portion and the through hole of the cone member mounted in the central recess, at least the anchor member is prevented from moving above the manhole bottom portion. Locking and fixing means for locking so as to
The manhole installation stabilization structure characterized by having. A plate body having rigidity laid on the bottom of the manhole in a range covering a predetermined area around the central recess;
The cone member has a size such that at least an upper end portion protrudes from the central concave portion in a state of being immersed in the central concave portion, and after the plate body is laid on the bottom of the manhole, the cone member is moved to the central concave portion. 2. The manhole installation stabilization structure according to claim 1, wherein the cone member is configured such that a load of the cone member is applied to the plate body in the state of being immersed. The area where the plate body is installed at the bottom of the manhole is
A taper bottom formed such that the surface position gradually decreases from the manhole inner wall side of the manhole bottom toward the center,
After the cone member is immersed and installed in the central recess, the anchor member is locked by the locking and fixing means in the inner recess of the cone member, and then concrete is placed on the taper bottom portion and the other manhole bottom portion is placed. The manhole installation stabilization structure according to claim 2, wherein the surface height is the same as the region. The plate body is
4. The apparatus according to claim 2, wherein at least a part thereof extends from the periphery of the central recess to a predetermined height of the inner wall of the manhole, and is fixed to the manhole at a portion extending to the inner wall of the manhole. A manhole installation stabilization structure given in any 1 paragraph.   The plate body is installed so as to extend in a direction connecting an upstream sewage pipe coupled to the manhole and a downstream sewage pipe, and the front and rear ends in the extending direction are respectively upstream from the manhole. The manhole installation stabilization structure according to any one of claims 2 and 3, wherein the manhole installation stabilizing structure further extends in a sewage pipe and a downstream side of the sewage pipe and extends on a bottom portion of the sewage pipe. The cone member is provided with a lid member for closing the inner recess,
In a state where the anchor member is fixed, a rust preventive agent is injected into the inner concave portion of the cone member, and the rust preventive agent is blocked by the lid member, and in this state, the concrete is placed on the tapered bottom portion. The manhole installation stabilization structure according to any one of claims 1 to 5, wherein the manhole installation stabilization structure is performed.   The manhole installation according to any one of claims 1 to 6, wherein a sealing means is provided to ensure water tightness between the anchor member and the through hole of the cone member and the through hole at the bottom of the manhole. Stabilization structure.

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