JP2001012183A - Seal structure of drift start/arrival for starting/ arriving shield machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal structure capable of further increasingly enhancing the internal pressure resistance of a seal member and corresponding to the requests of great depth and increase a bore of a shield machine. SOLUTION: This seal structure for a drift for shield machine start/arrival is constituted in such a way that at least one seal member 1 is fixed on an inner side of a buried ring, the seal member 1 forms a closed empty region by fixing both ends of an endless rubber or resin sheet, and fluid can be sucked and discharged in the closed empty region. The seal member 1 is fixed by a pressing fitting 6, and at least two taper parts are formed in a section where the seal member 1 is fixed on the pressing fitting 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure fixed to a joint between a vertical shaft and a horizontal shaft, and more particularly to a seal structure for preventing water leakage between a shield machine and a segment. The present invention relates to a contracting seal structure.

[0002]

2. Description of the Related Art In recent years, a shield method has been widely used for excavating an underpass, a tunnel, and the like. In the shield method, a vertical shaft is dug, and then a horizontal shaft such as a tunnel is formed by a shield machine. That is, the soil layer is cut by the rotary cutter with the propulsion of the shield machine, and the earth and sand taken into the cutter chamber is carried by a screw conveyor attached to the cutter chamber, and further discharged to the outside by a belt conveyor. Subsequently, segments are sequentially incorporated while the shield machine is being propelled, and a backing material is injected and filled between the segments and the excavated soil surface.

[0003] The applicant has already proposed the invention disclosed in Japanese Patent Application Laid-Open No. 8-35392 as a sealing structure in such a start / reach cross shaft of a shield machine. That is, FIG. 8 is a partially enlarged cross-sectional view of a portion of the seal member fixed by the holding metal. FIG. 9 is a sectional view showing a state in which the sealing member is fixed inside the embedding ring.

In FIG. 8, reference numeral 12 denotes a rubber sheet constituting a sealing member, and a reinforcing layer 13 made of two layers of nylon cords is embedded in the rubber sheet 12. This reinforcing layer 13 is divided into 13A and 13B at both ends, and a rubber material 14 forming a wedge portion 12A is sandwiched and integrated therebetween to form a portion of the rubber sheet 12 which is fixed by a holding member 15. I have.

[0005] Further, as shown in FIG. 9, the seal member 11 having a fixing portion as shown in FIG. That is, the wedge portions 1 at both ends
2A is sandwiched between presser fittings 15A and 15B, respectively, and this is fixed with bolts 17 and nuts 18.
Here, as shown in FIG. 9, the sealing member 11 is folded back and fixed so as to cover the one holding metal 15A, and the sealing member 11 and a part of the embedding ring 16 constitute a closed space. And this embedded ring 16
Is provided with a hole 19 for sending air into the closed space, and a pipe 20 connected to the hole 19 is provided. Therefore, the supply and discharge of air causes the seal member 11 to be in a state shown by a dotted line and a state shown by a solid line.

[0006] Such a sealing member 11 is used as shown in FIG. That is, the sealing member 11 comes into contact with the outer peripheral surface of the shield machine 21 (or comes into contact with the outer peripheral surface of the segment) by filling the closed space with air to be in an inflated state. Therefore, if proper air pressure is maintained, the sealing property is ensured. Here, a projection 21A such as an injection pipe is provided on the shield machine 21.
Exists. Therefore, with the movement of the shield machine 21, the sealing member exhibits the sealing performance while changing from the state of FIG. 10A to the state of FIG. 10B and further to the state of FIG. As described above, the already-proposed seal member 11 has an excellent effect that water leakage can be completely prevented even if the distance between the embedding ring 16 and the shield machine 21 (or segment) is different.

[0007]

However, even with the above-mentioned proposed sealing structure, there is a limit in the sealing performance. That is, when the depth is relatively shallow (within 30 m) and the diameter of the shield machine is small (less than 4000 mm), there is no problem at all, but recently, the depth is larger (more than 30 m) or There is an increasing demand for use with larger diameters (4000 mm to 13000 mm). In this case, since it is necessary to cope with an increase in groundwater pressure and an increase in the height of a projection such as an injection pipe in a shield machine, it is necessary to increase the internal pressure of the seal member.

Specifically, in order to withstand the groundwater pressure and to prevent the outflow of muddy water from between the horizontal shaft and the shield machine by following the change in the diameter of the shield machine, the internal pressure of the seal member is set higher than before. It must be 0.7 MPa or more. If the internal pressure is increased, in the above-described proposed seal structure, the seal member is supposed to fall out of the portion fixed to the embedding ring, and may not serve as the seal member.

Accordingly, the present invention is an improvement of such a proposed seal structure, which can further increase the internal pressure resistance of the seal member, and can meet the demand for a larger depth and a larger diameter of the shield machine. It is intended to provide a structure.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the invention is that first, at least two parts are provided at a portion of the seal member which is fixed to the holding member. The present invention relates to a seal structure having a tapered portion. Preferably, the angle of the tapered portion closest to the closed air space of the seal member is α, the angle of the next tapered portion is β, and the next is γ. , 0 ° <α <β <γ <... <
90 °. Further, the taper portion of the seal member is formed by embedding a material having hardness higher than that of the rubber or resin material forming the other portion, and two fiber reinforcing layers are formed in the rubber or resin sheet forming the seal member. Embed in the bias and set the cord angle to 70 ° ≦ θ <90 °
And a sealing structure. Further, a projection is formed at a portion of the sealing member that comes into contact with the embedding ring, and / or
Alternatively, the present invention relates to a seal structure in which a seal sheet is inserted, an uneven surface is formed at a portion that comes into contact with the shield machine, and / or the thickness is made thicker than other portions, and at least a portion that comes into contact with the shield machine is made of water-repellent rubber.

The seal member of the present invention has its both ends fixed to the inside of the embedding ring with holding metal fittings to form a closed space, but the position of the holding metal fitting is not particularly limited. In other words, both presser fittings may be arranged outside the closed air space, but it is also possible to arrange one of them in the closed air space and the other outside by folding back the seal member. However, when it is arranged in a closed space, it is preferable to provide a seal sheet for covering the holding metal.

Second, R is provided at the end of the holding member on the side to which the seal member is fixed and / or the upper end of the holding member, and R is provided at the corner of the holding member corresponding to the tapered portion. It relates to a seal structure. Further, a tooth form is provided on a flat portion of the holding metal fitting corresponding to a space between the tapered portions.

Third, the present invention relates to a seal structure in which a bolt hole is provided between a tapered portion of a seal member and a press fitting and an embedding ring are bolted using the bolt hole to fix the seal member. A recess is provided on the upper surface side of the presser fitting, and a head or nut of a fastening bolt is inserted into the recess.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is to form a closed space by fixing both ends of an endless rubber or resin sheet. Then, by allowing fluid to be sucked and discharged into the closed space, air is filled into the closed space in the same manner as the proposed seal structure, and the seal member is inflated to contact the outer peripheral surface of the shield machine to prevent water leakage. Is what you do.

Here, when the closed space is filled with air, the tensile force F acting on the seal member at the fixing portion by the presser fitting is given by P, where P is the internal pressure and r is the radius of the circle in the full state. = P · r. Therefore, when P is increased to withstand an increase in groundwater pressure, and when r is increased to cope with an increase in the projection height of the shield machine due to an increase in diameter, the tensile force F increases.

Therefore, in the present invention, at least two tapered portions are formed in the portion of the seal member fixed to the holding member to bear the tensile force F. That is, while the previously proposed seal structure has only one taper portion at the top and bottom, at least two are formed in series in the present invention. Therefore, when the tensile force F acts, the first taper portion bears a large amount of the tensile force F, and the second and subsequent taper portions successively bear the remaining tensile force F, so that a large amount of the tensile force F acts. However, the sealing member does not come off from the presser fitting, and the sealing property is ensured.

When the angle of the tapered portion closest to the closed space is α, the angle of the next tapered portion is β, and the next angle is γ, the angle of the tapered portion is 0 ° <α <β < γ <
... <90 ° is preferable. As described above, by decreasing the angle of the tapered portion where the tensile force F acts first and increasing the angle in order, the tensile force F can be equally applied to each tapered portion, and a larger internal pressure resistance is obtained. This is because it is possible to obtain and extend the life of the seal member.

Further, it is preferable that the tapered portion is formed by embedding a rubber or resin material having higher hardness than other portions of the seal member. Since the tensile force F becomes a compressive force of the rubber or resin material at the tapered portion,
This is because the higher the hardness, the more difficult it is to remove.

In the present invention, since the seal member is prevented from coming off from the presser fitting as described above, the destruction of the seal member is mainly rupture of the rubber or resin sheet. Therefore, inside the sheet constituting the sealing member,
The fiber reinforcing layer is embedded to form a strength member. Here, it is not always advisable to increase the number of fiber reinforcing layers. This is because wrinkles are likely to occur due to the difference between the inner and outer circumferences when the seal member is in a swelling state, and strength corresponding to the increase in the number of layers cannot be obtained.

Therefore, when the fiber reinforcing layer has a bias structure of two cords and one cord angle is θ,
It is preferable to satisfy the relation: ≤θ <90 °. This is the minimum number of layers when the bias structure is adopted so as to follow the deformation of the seal member. That is, not only can the difference between the inner and outer circumferences be minimized by using two layers, but also the cord angle normally distributed to about 55 °
This is because wrinkling can be eliminated while securing the minimum flexibility by allocating within the range of less than °.

On the other hand, it is preferable that a projection is formed on the rubber or resin sheet constituting the sealing member at a portion which comes into contact with the embedding ring. In the present invention, the tapered portion can be formed only on the side of the portion fixed to the presser fitting. In this case, the sealing property of the fluid in the closed space is secured only by the planar contact pressure between the sheet and the embedding ring. Will be done. Therefore, if there is a projection, the surface pressure is partially increased, and the sealing property is improved. Note that a seal sheet may be inserted between the seal member and the embedding ring instead of or together with the formation of the projection.

Here, there is no particular problem when the holding members at both ends of the seal member are arranged outside the closed space. However, when one of the holding members is arranged in the closed space by folding the seal member. In this case, there is a concern that leakage of the internal fluid may occur due to the bolt holes of the holding member. Therefore, in order to improve the sealing performance in this case, it is preferable to provide a seal sheet between the inner surface of the seal member and the inside of the embedding ring while covering the presser fitting included in the closed space.
In addition, the seal sheet may be provided separately from the seal member, and may be integrated with rubber or resin constituting the inner surface of the seal member.

Further, it is preferable to form an uneven surface at a portion outside the rubber or resin sheet which comes into contact with the shield machine. This is because the pressure bonding to the shield machine increases, and the sealing property is improved. Further, the lubricating oil enters the uneven portion, and particularly the sealing property is improved and maintained. In this case, it is preferable to increase the sheet hardness on the outer surface side by about 5 ° because it increases the pressure bonding property. Also,
The direction in which the irregularities are formed is preferably the circumferential direction (the direction perpendicular to the direction in which the shield machine is propelled) when the seal member is in an expanded state.

Further, it is preferable that a portion that comes into contact with the shield machine be thicker than other portions (excluding a portion fixed to the holding metal). This is to deal with damage caused by contact with the shield machine in advance.

If at least the portion of the seal member that contacts the shield machine is made of water-repellent rubber,
An excellent water stopping effect can be obtained for projections such as an injection pipe in a shield machine.

As the press fitting used in the present invention, it is preferable to provide an R at the end on the side where the seal member is fixed. As described above, in the present invention, the sealing member is prevented from coming off from the presser fitting, so that the destruction of the sealing member is mainly the breaking of the rubber or resin sheet itself, but the fixed-side end is sharp. This is not only because the angle change of the sheet becomes large and stress concentrates, but also the difference between the inner and outer circumferences becomes large and the sheet is easily broken.

Further, it is preferable to similarly provide R at the end on the upper surface side of the holding metal. This is because the outer surface of the seal member also comes into contact with the upper end of the holding member in the swelling state of the sealing member, and when one of the holding members is included in the closed space, the sealing member is in the contracted state. This is because the inner surface of the member also comes into contact with the end on the upper surface side of the included holding fitting.

Further, it is preferable to provide R also at the corner of the holding member corresponding to the tapered portion of the seal member. This is for reducing the local stress generated in the holding member and preventing the holding member from cracking. The degree of each R described above is preferably the maximum as long as it is allowed in relation to the thickness of the presser fitting, and specifically, is about 15 mm.

In addition, it is preferable to provide a tooth pattern on a flat portion of the press fitting corresponding to a portion between the tapered portions of the seal member. This is because the tooth mold bites into the outer surface of the rubber or resin sheet, and can contribute to preventing slippage due to the anti-slip effect. In particular, when a bolt hole is provided between the tapered portions described below, the load acting on the hole can be reduced by the bolt, and the breakage of the sheet starting from the bolt hole can be prevented.

In the present invention, the presser fitting is fixed to the embedding ring by fastening a bolt. A bolt hole is provided between the tapered portions of the seal member, and the presser fitting and the embedding ring are bolted using the bolt hole. Preferably, the sealing member is fixed. This is for preventing the opening of the presser fitting caused by the tensile force F acting on the tapered portion.

It is preferable that a recess is provided on the upper surface side of the holding member, and a head or nut of a fastening bolt is inserted into the recess. This is because the provision of the concave portion can prevent the seal member from being damaged by the bolt head or the nut. It is preferable to use a hexagon socket countersunk bolt as a fastening bolt because the thickness of the holding metal can be reduced while maintaining the required strength.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the seal structure of the present invention. Here, the seal member 1 is an endless rubber sheet having a width of 1000 mm, and a reinforcing layer 2 made of two layers of polyester cord and having a thickness of about 1 mm is embedded in the rubber sheet. The guaranteed strength of the polyester cord is 300 kgf / cm · ply, and the cord angle is 8 with respect to the endless direction of the sealing member.
Bias structure distributed to 0 ° (first layer = + 80
°, the second layer = -80 °). The thickness of the seal member 1 is 5 mm, but the thickness of the outer rubber 3 is increased to 10 mm at the portion that comes into contact with the shield machine. Here, a water-repellent rubber is used for the outer rubber 3.

The sealing member is not limited to a rubber sheet, but may be a resin sheet. Here, the type of rubber or resin is not particularly limited. Further, the reinforcing layer is not limited to the polyester cord, and various fiber cords such as a nylon cord can be used.

In FIG. 1, the holding member 6 of the seal member 1
Are fixed to the two tapered portions 4A and 4
B is formed. Here, the tapered portions 4A and 4B are formed by embedding high-hardness rubber having a hardness of 90 ° between the reinforcing layer 2 and the outer rubber 3. Also, the tapered part 4
The angle of A is 30 °, and the angle of the tapered portion 4B is 45 °. The seal member 1 is formed by bending and fixing a flat rubber sheet to form a closed air space as shown in FIG. 1. However, the tapered portions at both ends are formed upside down at the stage of the rubber sheet. Thereby, both ends can be fixed inside the embedding ring 7 after bending.

The end 6A of the holding member 6 shown in FIG. 1 on the side where the seal member 1 is fixed and the end 6B on the top side are provided with R having a radius of 15 mm. Therefore, the difference between the inner and outer circumferences of the reinforcing layer 2 is minimized. Also, R is provided at a corner 6C corresponding to the tapered portion 4A of the seal member 1 to reduce local stress. Further, a tooth mold 6D is provided on a flat portion of the holding member 6 corresponding to the portion between the tapered portions 4A and 4B of the seal member 1 to prevent the seal member 1 from coming off.

FIG. 2 is a cross-sectional view showing various examples of the holding member 6 used in the present invention. That is, the holding member 6 shown in FIG.
The shape of A and the end 6B is changed, and no tooth pattern is provided on the flat portion of the holding member 6 corresponding to the portion between the tapered portions 4A and 4B of the seal member 1. FIG. 2 (B)
2 has a hexagon socket head countersunk bolt 8 inserted and fixed in a concave portion on the upper surface side, and can be reduced in thickness as compared with the holding bracket 6 of FIG. Has become. The holding member 6 shown in FIG. 2C has a tapered portion 4A of the sealing member 1 in addition to the use of the flat head bolt 8 with a hexagonal hole.
The tooth mold 6D is provided on the flat part of the presser fitting 6 corresponding to the area between 4B. As described above, the holding fixture 6 of the present invention can be variously combined in consideration of sealing performance, productivity, workability, and the like.

In FIG. 2, a bolt hole is provided between the tapered portions 4A and 4B of the sealing member 1 and the holding member 6 and the embedding ring 7 are fixed with the bolt 8 using the bolt hole. I have. In addition, a projection 5 is formed at a portion of the seal member 1 which comes into contact with the embedding ring 7 so as to locally increase the surface pressure so as to reliably prevent the fluid in the closed space from leaking from the bolt hole. . In addition, bolt 8
By using the presser fittings 6 one by one, the presser fittings 6 themselves are made smaller, so that one presser fitting 6 can cope with various inner circumferences.

FIG. 3 shows a seal member 9A provided integrally with the inner surface rubber of the seal member 1 shown in FIG. That is, the seal sheet 9A covers the presser fitting 6 in the closed space and is attached to the embedding ring 7, thereby reliably preventing the fluid in the closed space from leaking from the insertion hole of the bolt 8. In addition, in the presser fitting 6 outside the closed space, the fluid in the closed space leaks from the insertion hole of the bolt 8 by inserting the seal sheet 9C between the seal member 1 and the embedding ring 7. Is reliably prevented.

FIG. 4 shows a case where the seal sheet is not integrated with the inner surface rubber of the seal member 1, but is formed as an individual seal sheet 9B. That is, one side of the seal sheet 9B is attached to the embedding ring 7 while covering the presser fitting 6 in the closed space, and the other side is inserted and fixed between the presser fitting 6 and the seal member 1 to secure the seal. It is something that has ensured sex.

FIG. 5 shows that, when the closed space is formed, the seal member is not folded back to include one of the holding members.
A closed space is formed by fixing both ends of the seal member 1 with holding metal members 6 respectively. In this case, the sealing member 1
Has a symmetrical shape, and the tapered portions 4A and 4B at both ends are formed on the same side at the stage of the rubber sheet.

For the three types of seal structures of the present invention, the maximum load was measured by performing a tensile test. That is,
As shown in FIG. 6, the seal member 1 was attached to the test device 10 at an angle of 45 ° at a position where the seal member 1 was fixed to the presser fitting 6, and the test device 10 was pulled from both sides to measure the maximum load. Here, the seal member 1 is formed with tapered portions 4A and 4B, and the angle of the tapered portion 4A is 30.
°, and the angle of the tapered portion 4B is 45 °. Note that the maximum load is the breaking load of the seal member 1,
Alternatively, the value is obtained when the seal member 1 comes out of the presser fitting 6 and the load does not increase any more.

FIG. 7 is a graph showing the results of the tensile test. Here, the first embodiment is one in which high hardness rubber is embedded in both tapered portions, and a tooth pattern is provided in a flat portion of the holding metal fitting corresponding to the space between both tapered portions. Example 2
Means that the tooth form in Example 1 is omitted, and in Example 3, high hardness rubber is not embedded in both tapered portions (a tapered portion is formed with rubber having the same hardness as other portions), and The holding fixture has no tooth pattern (planar shape).

As shown in FIG. 7, each of the embodiments has a safety factor close to twice that of the normal use area, and can sufficiently cope with an increase in the groundwater pressure and an increase in the height of the protrusion in the shield machine. . In particular, in Examples 1 and 2 in which high-hardness rubber is embedded in the tapered portion, the safety factor is 2.5 or more, and the fixing bolt is tightened in Example 1 in which the tooth form is provided on the flat portion of the holding member. If the torque is appropriate, a safety factor of 3 can be ensured.

[0044]

As described above, by employing the seal structure of the present invention, the internal pressure resistance of the seal member can be further increased, and the demand for a larger depth and a larger diameter of the shield machine can be sufficiently satisfied. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing a seal structure of the present invention.

FIG. 2 is a cross-sectional view showing various examples of a holding member used in the present invention.

FIG. 3 is a sectional view showing another example of the seal structure of the present invention.

FIG. 4 is a sectional view showing a further example of the seal structure of the present invention.

FIG. 5 is a sectional view showing a still further example of the seal structure of the present invention.

FIG. 6 is a diagram illustrating a tensile test method for a seal member.

FIG. 7 is a graph showing a tensile test result of the seal member.

FIG. 8 is a cross-sectional view showing a fixing portion of a previously proposed seal member.

FIG. 9 is a cross-sectional view showing a state where the sealing member is fixed to the embedding ring.

FIG. 10 is a cross-sectional view illustrating a change in a seal member caused by movement of the shield machine.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 sealing member 2 reinforcing layer 3 outer rubber 4A, 4B taper portion 5 protrusion 6 holding bracket 6A fixed end 6B top end 6C corner 6D flat portion 7 embedded ring 8 ‥ Bolts 9A, 9B, 9C ‥ Seal sheet 10 ‥ Testing device 11 ‥ Seal member 12 ‥ Rubber sheet 12A ‥ Wedge portion 13 ‥ Reinforcement layer 13A, 13B ‥ Division portion 14 ‥ Rubber material 15, 15A, 15B ‥ Pressing bracket 16 ‥ Embedded ring 17 Bolt 18 Nut 19 Air vent 20 Piping 21 Shield machine 21 A Projection

Claims (18)

[Claims] At least one seal member is fixed inside an embedded ring provided at a connection port of a horizontal shaft extending from a vertical shaft, and the seal member fixes both ends of an endless rubber or resin sheet. A seal structure for a cross shaft for starting and reaching a shield machine which forms a closed space and is capable of sucking and discharging fluid in the closed space, wherein a seal member is fixed with a holding metal fitting and a holding member for the seal member is held down. Starting a shield machine characterized by forming at least two tapered parts in the part fixed to the bracket
Seal structure for the cross shaft. 2. When the angle of the tapered portion closest to the closed air space is α, the angle of the next tapered portion is β, and the next angle is γ, 0 ° <α <β <γ <... <90 ° The seal structure of a shield shaft for starting and reaching a shield machine according to claim 1, wherein: 3. The sealing member according to claim 1, wherein the tapered portion of the sealing member is formed by embedding a material having a hardness higher than that of a rubber or resin material forming another portion. The seal structure of the horizontal shaft for starting and reaching the shield machine. 4. The seal structure according to claim 1, wherein a fiber reinforcing layer is buried in a rubber or resin sheet constituting the seal member. 5. When the fiber reinforcing layer has a bias structure of two cords and one cord angle is θ, 70 ° ≦ θ.
The seal structure of the shield shaft for starting and reaching a shield machine according to claim 4, wherein the angle is set to <90 °. 6. The seal according to claim 1, wherein a protrusion is formed and / or a seal sheet is inserted into a portion of the seal member that comes into contact with the embedding ring. Construction. 7. A closed space is formed by fixing one end of the sealing member inside the embedding ring with a holding metal, and then turning back the other end of the sealing member and enclosing the holding metal and fixing the inside of the embedding ring. The seal structure of a shaft for starting and reaching a shield machine according to any one of claims 1 to 6, wherein: 8. The shield machine according to claim 7, wherein a seal sheet is provided between the inner surface of the seal member and the inside of the embedding ring while covering the presser fitting included in the closed space.・ Seal structure of the cross shaft for arrival. 9. The seal structure according to claim 8, wherein the seal sheet is integrated with rubber or resin constituting the inner surface of the seal member. 10. An uneven surface is formed on a portion of the seal member which comes into contact with the shield machine.
10. The seal structure of a shaft for starting and reaching a shield machine according to any one of items 9 to 9. 11. The sealing member according to claim 1, wherein a portion in contact with the shield machine is thicker than other portions (excluding a portion fixed to the holding metal).
The seal structure of the cross shaft for starting and reaching the shield machine according to 0. 12. The seal structure according to claim 1, wherein at least a portion of the seal member that contacts the shield machine is made of a water-repellent rubber. 13. An end portion of a holding member for fixing a seal member, wherein R is provided at an end of the holding member.
3. The seal structure of the horizontal shaft for starting and reaching the shield machine according to 2. 14. The seal structure for a cross shaft for starting and reaching a shield machine according to claim 1, wherein an R is provided at an end on the upper surface side of the presser fitting. 15. The fixing device according to claim 1, wherein R is provided at a corner of the holding member corresponding to the tapered portion of the sealing member.
15. The seal structure of a shaft for starting and reaching a shield machine according to any one of items 14 to 14. 16. The seal structure of a shaft for starting and reaching a shield machine according to claim 1, wherein a tooth form is provided on a flat portion of the presser fitting corresponding to a portion between the tapered portions of the seal member. . 17. The sealing member according to claim 1, wherein a bolt hole is provided between the tapered portions of the sealing member, and the holding member and the embedding ring are bolted using the bolt hole to fix the sealing member. The seal structure of the horizontal shaft for starting and reaching the shield machine described in the above. 18. The seal structure according to claim 17, wherein a recess is provided on the upper surface side of the presser fitting, and a head or a nut of a fastening bolt is inserted into the recess.