KR20050082143A - A concrete manhole - Google Patents

Abstract

In the present invention, when connecting the concrete manhole and the connection pipe, watertight manhole, connection structure of the manhole, the manhole to achieve a reliable watertightness so that no leakage occurs in the connection between the wall and the connection of the manhole at a simple and low cost And a construction method.

In the present invention, the connection hole of the form larger in diameter than the outer diameter of the connection pipe is formed on both sides of the wall, and the manhole is formed in the upper side of the connection hole outside the wall is formed concave, the connection hole of the manhole A connecting tube is inserted inside, and an elastic blocking member is installed on the outer periphery of the end of the connecting tube to elastically fit in the gap formed by the connecting tube and the connecting hole to seal the connecting hole. Watertight manholes, characterized in that the grout is filled in the space between the connection hole, the manhole connection structure and construction method are provided.

Description

Watertight Manholes {A Concrete Manhole}

The present invention relates to a watertight manhole, specifically, in inserting and connecting a connection pipe into a connection hole formed in a concrete manhole, so that water leakage does not occur at the coupling portion between the wall and the connection pipe of the manhole at a simple and low cost. The present invention relates to a watertight manhole for achieving a certain watertightness.

1 is a cross-sectional view of a conventional concrete manhole, which is installed in sewage pipes and the like. As shown in the figure, the conventional manhole 10 is composed of a cylindrical or rectangular wall (11), each of the lower side of the wall 11 is formed with a connection hole 12, respectively In the connection hole 12, connection pipes 13 and 14 are inserted and coupled. The connection pipes 13 and 14 may be sewage pipes, power lines, or gas pipes. An opening 15 is formed at an upper portion of the wall 11 to communicate with a road, and a cover 16 is installed at the opening 15.

One of the most problematic problems in the above manhole is the watertightness at the portion where the connection pipes 13 and 14 and the wall 11 are connected. As shown in FIG. 1, in the state in which the connection pipes 13 and 14 are inserted into the connection hole 12 of the manhole 10 made of concrete, the connection hole 12 and the connection pipes 13 and 14. Inevitably, there is a gap between them, and the leakage occurs mainly through these gaps. If a leak occurs at the connection between the manhole wall 11 and the connection pipes 13 and 14, the sewage leaks out and contaminates the ground, and the ground sinks due to moisture that penetrates the ground, thereby causing serious damage to the manhole structure itself. It will adversely affect. In particular, when the manhole is for power wiring, the wastewater flows in through the gap generated in the connection portion between the manhole wall 11 and the connection pipes 13 and 14, which seriously affects the power line.

The most common method conventionally adopted for the watertightening of the connection between the manhole wall 11 and the connection pipes 13 and 14 is to apply cement paste or the like around the connection part inside and outside the manhole wall 11. . That is, as shown in FIG. 1, the cement paste 17 is applied to the inner and outer circumferences of the gap existing between the connection hole 12 and the connection pipes 13 and 14 of the wall 11 to achieve watertightening. It was planned.

However, it is not possible to achieve complete watertightening by merely blocking the inside and the outside of the gap while leaving the gap between the wall 11 and the connecting pipes 13 and 14 as it is. This is because cracks occur in the inner and outer cement pastes 17 even by slight ground changes, and the water penetrated through the cracks easily flows out to the inside or through the gaps.

As one of the prior arts proposed for watertightening the connection of the manhole and the connection pipe, the technique disclosed in Utility Model Registration No. 339306 discloses a support means having a shape that protrudes in a semicircular shape around the outside of the support pipe. This structure has a structure in which the supporting means portion is embedded in the side wall of the manhole in advance. In this structure, the waterway portion protruding from the support means tube is embedded in the wall of the manhole, and the length of the path through which water flows out by the protruding support means lengthens, causing water to leak through the gap between the wall and the support means pipe. It is effective to block. However, since the means tube has a form pre-embedded in the manhole wall, it is inconvenient to transport the manholes, and there is a disadvantage that it is not economical because the process of protruding the means means to the means tube must be made in advance. Moreover, even if the protruding support means is pre-buried, it is difficult to perform the synthesizing action of the support means of the steel and the concrete wall smoothly, and a gap between the support means and the concrete wall may occur. However, conventionally, there is no means to fill the gap between the branch pipe and the concrete wall, and the watertightening is completely completed because it can only be finished by simply applying a cement paste around the connection between the wall and the branch pipe while leaving the gap as it is. There was a hard disadvantage. In addition, since the pre-buried tube of a short length is pre-buried, considerable precision construction is required at the time of joining the tube, and if the extreme care is not taken when connecting the connecting tube to the support tube, a lateral load acts on the support tube. There was a disadvantage that the construction is worse because the gap can be further increased.

The present invention was developed in order to solve the above conventional problems, the object of the present invention, to ensure that the connection portion between the wall and the connection pipe of the concrete manhole to be surely sealed to maximize the watertightness, with a simple and low cost It is to provide a new and innovative structure of manhole, manhole connecting structure and construction method to enable construction.

In order to achieve the above object, a manhole having a wall, wherein the wall is formed with a connection hole into which a connection pipe is inserted and coupled, the connection hole has a predetermined thickness around the connection pipe between the connection pipes. It is formed on both sides of the wall in the form of a larger diameter than the outer diameter of the connecting pipe so as to secure a space for filling the grout of the; In order to inject grout into the gap between the connection hole and the connection pipe, a manhole is provided, wherein an injection groove is formed to be recessed a predetermined depth from an upper surface of the connection hole outside the wall.

Specifically, in the present invention, as a specific embodiment of the manhole, the manhole is provided on the inner circumferential surface of the connecting hole is provided with a watertight groove concave to a predetermined depth radially outward.

Here, it is preferable that the connection hole is formed in a tapered form in which the aperture gradually expands from the inside of the wall toward the outside in the radial direction. On the other hand, in the present invention, the aggregates constituting the wall by the aggregate exposure finish treatment to remove the cement paste on the inner circumferential surface of the connection hole may be exposed in an uneven manner.

In the present invention, in connection with the manhole, as a coupling structure of a connection hole formed in the wall of the manhole and a connection pipe inserted into the connection hole, the connection hole is predetermined around the connection pipe between the connection pipe. It is formed on both sides of the wall in the form of a larger diameter than the outer diameter of the connection tube to be connected so as to secure a space for filling the grout of the thickness; An injection groove concave to a predetermined depth is formed from an upper surface of the connection hole outside the wall to inject grout into the gap between the connection hole and the connection pipe; An elastic blocking member is installed at an outer circumference of the inner end of the connection tube inserted into the connection hole to elastically fit in a gap formed by the connection tube and the connection hole to seal the connection hole; A shielding member is installed around the connection hole of the outer wall of the wall to block the outside of the connection hole and function as a formwork for grout filling and to protect the filled grout; The grout is filled in the space between the connection pipe and the connection hole through the injection groove, thereby providing a coupling structure of the connection hole and the connection pipe of the manhole for tightly coupling the connection hole and the connection pipe.

As an embodiment of the coupling structure of the present invention, a watertight groove is formed in the inner circumferential surface of the connecting hole in a radially concave manner, and the grout may be filled in the watertight groove. Further, in the above coupling structure, the shielding member is made of a waterproof sheet, a part of the waterproof sheet is attached to the surface of the wall and fixed, and the remaining part of the waterproof sheet is fitted to the outer circumference of the connection pipe to the band member. Is fixed by.

In addition, in the present invention, as a joining method for inserting and joining a connection tube into a connection hole formed in the wall of the manhole, the end of the connection tube is inserted into the connection hole, and elasticity to the end of the connection tube projecting into the wall. A first step of installing the blocking member; A second step of pressurizing the connection pipe provided with the elastic blocking member to the outside so that a part of the elastic blocking member is inserted into the connecting hole and the other part is elastically in close contact with the end of the connecting hole; A third step of installing a shielding member around the connection hole of the outer wall of the wall to block the outside of the connection hole to function as a formwork for grout filling and to protect the filled grout; And a fourth step of injecting grout into a space formed by the connection pipe and the connection hole through an injection groove formed at an upper side of the connection hole on the outside of the wall. This is provided.

In the above construction method, the shielding member is made of a waterproof sheet; In installing the shielding member, applying an adhesive for adhering the shielding member around the connection hole outside the wall; One side of the shielding member is attached to the surface of the wall to which the adhesive is applied, and the remaining part is bound to the outer circumference of the connection tube by a band member.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A and 2B illustrate a manhole according to a preferred embodiment of the present invention, in which a cross-sectional view showing an enlarged portion of a manhole is shown in FIG. 2A, and in FIG. 2B, in the 'A' direction of FIG. 2A. A perspective view of the connecting hole portion is shown.

As shown in Figure 2a and 2b, the manhole 20 according to the present invention, the connection hole 22 is inserted into the connection tube 40 is formed in the cylindrical or rectangular wall 21, the connection hole It consists of a structure in which the injection groove 23 is formed on the outer upper side of the (22).

The connection hole 22 is a hole for inserting the connection tube, in the present invention, in order to secure a space to fill the grout around the inserted connection tube 40 to embed the connection tube 40, The connecting hole 22 has a larger diameter than the outer diameter of the connecting pipe.

The injection groove 23 is a portion for injecting grout into a gap between the connection hole 22 and the connection pipe, and is formed concave to a predetermined depth from an upper surface of the connection hole 22 outside the wall 21. . Thus, since the injection groove 23 is formed in the wall 21 in advance, filling grout becomes very convenient.

As shown in FIG. 2A, the connection hole 22 is preferably formed in a tapered shape in which the diameter gradually increases from the inner side of the wall 21 toward the radial outer side. The larger the diameter of the connection hole 22 is from the inside of the wall 21 to the outside, the larger the diameter of the injection groove 23 and the smaller the distance from the injection groove 23 in the axial direction. Therefore, the grout can be filled well without gap toward the injection groove 23 from the direction furthest from the injection groove (23).

In a preferred embodiment of the present invention, the inner peripheral surface of the connecting hole 22 is preferably formed in the water-sealed groove 24 concave radially outward. At least one watertight groove 24 may be formed. The grout is also filled in the watertight groove 24. Since the watertight groove 24 is formed to a predetermined depth from the inner surface of the connection hole 22, the watertight groove 24 formed deep even if a leak occurs due to a gap between the filled grout and the surface of the connection hole 22. The longer the flow path of water can be used for water-tightening. In addition, when the grout is filled by the watertight grooves 24, the synthesis with the wall 21 can be assisted to improve the integration.

As shown in the figure, a ventilation groove 25 communicating with the atmosphere may be formed at the top of the watertight groove 24. The ventilation groove 25 serves to prevent air from forming in the grout by allowing the air inside to escape when the grout is filled in the space between the connection hole 22 and the connection pipe. Of course, when the grout is filled in the connecting hole 22, the grout is also filled in the vent groove 25 and sealed.

3A and 3B show other embodiments of the connecting hole 22 of the manhole 20.

The connecting hole 22a shown in FIG. 3A has a smooth surface without the watertight groove 24 of the manhole 20 described above with reference to FIG. 2A. The connecting hole 22b shown in FIG. 3B has a form in which the surface of the concave-convex surface 22c is formed by the aggregate forming the wall 21. The concave-convex surface 22c, like the above-described watertight groove 24, serves to extend the water path and at the same time assist the synthesizing of the grout with the wall 21 to achieve a more perfect water-tightening. This uneven surface 22c is exposed to the aggregates 22d constituting the wall 21 by subjecting the aggregate exposure finishing treatment to remove cement paste from the inner surface of the connection hole 22b when the wall 21 is placed. It is made by forming irregularities. Details thereof will be described later.

In the accompanying drawings, FIGS. 4A to 4C illustrate an example of a method of forming a manhole connecting hole of the present invention, and a method of forming a connecting hole 22 having a watertight groove 24 as shown in FIG. 2A is provided. Preferred examples are shown.

First, as shown in FIG. 4A, a ring 31 for forming a watertight groove 24 is installed on an outer circumference of the formwork 30 for forming the connection hole 22. Subsequently, as shown in FIG. 4B, the linkage formwork 30 having the ring 31 is installed in the wall formwork 32, and then the concrete 33 is poured into the wall formwork 32 to form a wall. To form. Subsequently, as shown in FIG. 4C, when the connecting formwork 30 is removed and the ring 31 is subsequently removed, the connecting hole 22 is formed on the wall 21 formed by the concrete 33 pouring. And a watertight groove 24.

5A and 5B, there is shown a view for explaining another example of a method of forming the connection hole 22 of the manhole according to the present invention. This shows a preferred example of how to form the uneven surface 22c by the exposure of the aggregate 22d on the surface of the connecting hole 22, as shown in FIG. 3B.

First, as shown in Figure 5a, the curing retardant 34 is applied to the surface of the connecting die formwork (30). Subsequently, the formwork 30 for the connection hole, to which the curing retardant 34 is applied, is installed on the formwork 32 for the wall, and the concrete 33 is poured to form the wall. Subsequently, when the connection die 30 is removed, a connection hole 22 is formed in the wall 21. The surface of the connection hole 22 is cement which has not yet been hardened by a pre-coated curing retardant 34. The paste is present. At this time, when water is sprayed using a predetermined nozzle 35 on the inner circumferential surface of the connection hole 22, the cement is washed off and the aggregates 22d are irregularly exposed on the surface of the connection hole 22.

6A is a cross-sectional view illustrating a structure in which a connection hole 22 and a connection pipe are connected according to the present invention in the manhole 20 described above, and FIG. 6B is a perspective view. The same reference numerals are used to refer to the same elements as the above-described embodiments, and redundant description thereof will be omitted.

As shown in FIGS. 6A and 6B, the manhole 20 has a connection hole 22 formed in the wall 21 thereof, and an injection groove 23 above the connection hole 22 outside the wall 21. ) Is provided. The inner wall circumference of the connecting hole 22 is provided with a watertight groove 24. In the manhole 20, the shape of the connection hole 22, in addition to the watertight groove 24 is formed, the shape of the connection hole 22a (22b) as described above in Figures 3a and 3b. May have

In addition, the connection pipe 40 is inserted into the connection hole 22 inside the manhole 20. In the embodiment shown in the figure, the connecting tube 40 is made of a corrugated connecting tube having an uneven portion, that is, a concave portion 41 and a convex portion 42 on an outer surface thereof. The connection pipe 40 may be made of a synthetic resin material, steel pipe or concrete pipe. In addition, the connection pipe 40 does not necessarily need to be a waveform connection pipe. That is, the outer surface may have a smooth shape.

In the coupling structure of the present invention, the elastic blocking member 50 is provided on the outer periphery of the inner end of the connection pipe 40. The elastic blocking member 50 is elastically fitted in the gap formed between the connecting tube 40 and the connecting hole 22 to seal the connecting hole 22 to prevent the grout from leaking when grout is injected. The elastic blocking member 50 may be made of rubber having elasticity or foaming rubber having elasticity. In the embodiment shown in the figure, the elastic blocking member 50 has a convex portion 51 and a concave portion 52 in accordance with the outer surface of the corrugated connection tube 40, the concave of the connection tube 40 It is fitted to the part 41 and the convex part 42.

The grout 60 is filled in the space between the connection pipe 40 and the connection hole 22. In order to prevent the grout 60 from leaking, the elastic blocking member 50 is connected to the connection hole 22. ) Should be in close contact with a constant force. To this end, it is preferable to press the inner end of the connection tube 40 to the outside, or to allow the grout 60 to be injected while keeping the connection tube 40 pulled from the outside.

On the other hand, the shielding member 70 is provided around the connecting hole 22 on the surface of the wall 21. The shielding member 70 serves as a formwork for filling the grout 60 by blocking the outside of the connection hole 22. However, the shielding member 70 is permanently installed on the surface of the wall 21 without being removed even after construction is completed, thereby forming a part of the structure, thereby serving to protect the grout 60 therein. Do.

The shielding member 70 may be formed of a waterproof sheet. A part of the waterproof sheet, ie, an outer portion thereof, is attached to the surface of the wall 21, and the other portion, ie, a center portion, is connected to the connection pipe ( It is fitted to the outer circumference of 21 and bound by the band member 80. In addition, the shielding member 70 is preferably made of a viscous rubber material having a property that can freely deform and maintain the deformed form without being elastically restored to its original state when the deformation is applied. As the viscous rubber material, asphalt rubber sheets are suitable. As the band member 80, a rubber ring or a rubber band may be used.

7A and 7B are drawings showing preferred structural examples of the waterproof sheets.

First, the shielding member 70a shown in FIG. 7A has a circular sheet shape, and a hole 71 is formed in the center thereof. And the notch line 73 is formed radially from the said center hole 71 to the point to the virtual outer diameter line 72 with respect to the connection pipe 40 at regular intervals. Several blade pieces 74 are formed by the notch 73. When such a hole 71 in the center of the shielding member 70a is inserted into the connection pipe 40, the blade piece 74 of the shielding member 70 is opened while being fitted. At least one cut line 73a of the cut lines 73 may extend to the outermost portion of the shielding member 70a. Therefore, the shielding member 70a may be opened on one side or both sides, and may be inserted laterally in the connecting pipe 40 by using the opening, thereby conveniently installing at any point in the middle of the connecting pipe 40. Can be.

Accompanying drawings, the shielding member 70b illustrated in FIG. 7B has a rectangular outer shape. Other configurations than that are the same as those of the above-described shielding member 70a.

The grout 60 is filled between the shielding member 70, the elastic blocking member 50, the connection pipe 40 and the connection hole 22, the grout 60 is preferably made of non-contraction mortar. . The grout 60 is introduced into the space secured between the connection pipe 40 and the connection hole 22 through the injection groove 23, and also fills the watertight groove 24 of the connection hole 22. The concave portion 41 on the outer surface of the connecting tube 40 is also filled. The grout 60 filled in this way improves the watertightness by helping the connection pipe 40 and the wall 21 to be in close contact with each other to form a solid composite cross section. Moreover, the surface of the grout 60 and the connection hole 22 is formed by the concave portion 41 and the convex portion 42 formed in the watertight groove 24 formed in the connection hole 22 and the surface of the connection pipe 40. As the water path between the grout 60 and the connection pipe 40 becomes longer, the watertightness is further improved.

8A through 8D are views sequentially illustrating a construction process of a manhole structure according to a preferred embodiment of the present invention.

First, the trench is installed and the manhole 20 is installed therein. Then, as shown in FIG. 8A, the end of the connection pipe 40 is connected to the connection hole 22 formed in the wall 21 of the manhole 20. The elastic blocking member 50 is inserted into the end of the connecting pipe 40 protruding into the wall 21 (first step).

Subsequently, as shown in FIG. 8B, the connecting pipe 40 provided with the elastic blocking member 50 is pulled out or pressed from the inside to the outside (second step). Then, a part of the elastic blocking member 50 is inserted into the connection hole 22 and at the same time the remaining part is elastically in close contact with the end of the connection hole 22, the connection hole 22 is completely sealed. . In the embodiment shown in the figure, by pressing the end of the connecting pipe 40 using a simple clamp 90 in the interior of the wall 21, the elastic blocking member 50 is connected to the connecting hole 22 It is in close contact.

Subsequently, as shown in FIG. 8C, a shielding member 70 for blocking the connection hole 22 is provided outside the wall 21 (third step). One side of the shielding member 70 is attached to the surface of the wall 21, and the remaining part is bound to the outer periphery of the connection pipe 40 by the band member 80. The shielding member 70 serves as a formwork blocking the outside of the connection hole 22.

In order to attach the shielding member 70, before or after the first process or the second process, an adhesive for bonding the shielding member 70 around the connection hole 22 outside the wall 21 ( 100) is applied. The state in which the adhesive 100 is applied is also shown in FIGS. 8A and 8B.

When the shielding member 70 is bound to the outer circumference of the connection pipe 40 by the band member 80, the connection pipe 40 is formed into a waveform so that the connection of the portion to which the band member 80 is fastened is connected. The outer circumferential surface of the tube 40 may be irregular. At this time, as shown in Figure 8c, prior to fastening the band member 80, it is preferable to flatten the surface by inserting the blocking ring 110 in the recess 41 of the connection pipe (40).

Thereafter, as shown in Figure 8d, through the injection groove 23 formed on the upper side of the connection hole 22 outside the wall 21, in the space formed by the connection pipe 40 and the connection hole 22 The grout 60 is injected (third step). When the non-shrink mortar is used as the grout 60, the grout 60 is also filled in the watertight groove 24 of the connecting hole 22 due to the excellent flowability of the non-shrink mortar, and the concave of the connection pipe 40 The part 41 is also filled. Therefore, the contact tube 40 and the wall 21 are helped to be in close contact to achieve a firm composite cross section, thereby improving watertightness. Moreover, the surface of the grout 60 and the connection hole 22 is formed by the concave portion 41 and the convex portion 42 formed in the watertight groove 24 formed in the connection hole 22 and the surface of the connection pipe 40. As the water path between the grout 60 and the connection pipe 40 becomes longer, the watertightness is further improved.

Thereafter, after the grout 60 has hardened, the clamp 90 is removed and backfilled to complete the construction.

Meanwhile, although not illustrated in the drawings, a water-expandable index ring may be installed in the watertight groove 24. Since the water-expandable resin ring has a property of expanding by moisture, it is usually maintained a small cross-section, when the grout (60) is injected, it expands due to the moisture to fill the watertight groove (24) to achieve water-tightening Will be.

Although specific embodiments of the present invention shown in the accompanying drawings have been described in detail above, this is only one example of a preferred embodiment of the present invention, and the protection scope of the present invention is not limited thereto. Therefore, the embodiments of the present invention as described above can be variously modified and equivalent other embodiments by those of ordinary skill in the art within the technical spirit of the present invention, such modifications and equivalent other embodiments are It goes without saying that it belongs to the appended claims of the invention.

As described above, in the present invention, the connecting pipe is inserted into the connecting hole of the manhole and integrated into the wall by the grout, and is easily sealed by the shielding member and the elastic blocking member provided inside and outside the connecting hole. It has a certain structure.

Conventionally, the water-tightening construction of the connection part of a connection pipe was only the extent which cement paste was applied to the inside and the exterior of the gap, leaving the space | interval between a wall and a connection pipe as it is. Therefore, even with slight ground changes, cracks are generated in the inner and outer cement pastes, and the water penetrated through the cracks can not be completely watertight, such as easily leaking out to the inside or through the gap.

However, in the present invention, the gap between the connection hole and the connection pipe is completely blocked by the grout, and the sealing of the connection hole is more reliably achieved by the adoption of the shielding portion and the elastic blocking member, so that a very reliable watertightness is achieved. It has the advantage of being made.

In addition, in the present invention, there is no need to purchase a separate member such as a support pipe in advance, and the construction is completed by inserting the connecting pipe into the wall at the construction site, and filling the grout, so that the transport and construction of the manhole is more convenient. There is this.

Further, in the present invention, the grout has a structure in which the watertight groove of the connection hole and the concave portion of the connection pipe surface are filled, whereby the connection pipe and the wall can form a firm composite cross section with excellent adhesion, and thus watertightness is achieved. It has the advantage of being further improved.

In addition, even if a gap occurs between the grout and the connecting pipe, the water way is lengthened by the watertight groove formed in the connecting hole has the advantage that the watertightness is further improved.

1 is a cross-sectional view showing the structure of a conventional manhole.

2A and 2B illustrate a manhole according to a preferred embodiment of the present invention. FIG. 2A is an enlarged cross-sectional view of a connecting hole of a manhole, and FIG. 2B is a perspective view taken from the direction 'A' of FIG. 2A.

3a and 3b are views showing other embodiments of the connection hole of the manhole.

4A to 4C are views for explaining an example of a method of forming a connection hole of a manhole according to the present invention.

5A and 5B are views for explaining another example of a method of forming a connection hole of a manhole according to the present invention.

Figure 6a is a cross-sectional view showing a coupling structure of the connecting hole and the connection pipe of the manhole according to a preferred embodiment of the present invention, Figure 6b is a schematic perspective view of the coupling portion.

7A and 7B are views showing preferable structural examples of the shielding members according to the present invention.

8A to 8D are views sequentially illustrating a process of constructing a coupling structure of a manhole and a connection pipe according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

20: manhole 21: wall

22: connecting hole 23: injection groove

24: watertight groove 25: ventilation groove

30: formwork for the connector 31: ring

32: wall formwork 33: concrete

34: curing delay agent 35: nozzle

40: connecting tube 50: elastic blocking member

60 grout 70 shielding member

80: band member 90: clamp

100: adhesive

Claims (1)

In the manhole having a wall, the wall is formed with a connection hole is inserted into the connection pipe, The connecting holes are formed on both sides of the wall in a shape larger than the outer diameter of the connecting pipe so that a space for filling a grout having a predetermined thickness is secured between the connecting pipe and the connecting pipe; An injection groove concave to a predetermined depth is formed from an upper surface of the connection hole outside the wall to inject grout into the gap between the connection hole and the connection pipe; The inner circumferential surface of the connecting hole is provided with a watertight groove concave to a predetermined depth radially outward; When the grout is filled in the space between the connection hole and the connection pipe to the outside to discharge the air collected in the watertight grooves to the outside of the watertight grooves a manhole, characterized in that the ventilation grooves are communicated with the outside.