JP2937823B2 - Wellhead sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wellhead sealing device installed at a wellhead, and more particularly, to a tunnel disposed in a wellbore formed on the ground in communication with the inner peripheral surface of the wellhead and the wellhead. The present invention relates to a wellbore sealing device for sealing between a pipe line forming body such as a segment and a buried pipe, or an outer peripheral surface of a leading machine such as a shield excavator or a blade pipe installed at the tip thereof.

[0002]

2. Description of the Related Art Conventionally, a wellhead formed on a pit wall such as a vertical pit or a tunnel pit whose inner lining has been completed, or a wellhead formed on the surface of the ground, has an inner peripheral surface of the wellhead, for example, a shield method. Between the outer peripheral surface of a leading device such as a shield excavator used in a tunnel or a piercing tube used in a propulsion method or the outer peripheral surface of a pipe line forming body such as a tunnel segment or a buried pipe continuously provided behind the leading device. Is provided. For example, Japanese Patent Publication No. 3-3797 discloses a wellhead sealing device provided at a wellhead (starting port) of a shield excavator of a shaft.
Japanese Patent No. 0392 discloses a wellhead sealing device provided at a shield machine start side entrance (starting port) or a shield machine reaching side entrance (arrival port) of a shaft.

[0003] The starting port sealing device disclosed in the above publication is attached to the starting port of a shaft and seals between the inner peripheral surface of the starting port and the outer peripheral surface of the shield machine or tunnel segment. A seal member and a plurality of swinging backing plates arranged along the side surface of the elastic seal member on the inner side of the shaft and swingably attached to the wellhead such that the tip is expanded to the outside of the shaft. And This rocking backing plate, when expanded to the side of the excavation pit, has its tip abutting on the outer peripheral surface of the shield machine or tunnel segment and between the inner peripheral surface of the wellhead and the outer peripheral surface of the shield machine or tunnel segment. Since the back surface of the elastic seal member is supported, the elastic seal member can be pressure-resistant supported against pressure such as earth pressure and water pressure on the digging pit side.

On the other hand, the sealing device for the access port disclosed in the above publication is attached to the access port of a shaft and seals between an inner peripheral surface of the access port and an outer peripheral surface of a shield machine or a tunnel segment. An elastic seal member, and a plurality of rockers arranged along the side surface of the elastic seal member on the inner side of the shaft, and swingably attached to the wellhead such that the tip is expanded toward the inner side of the shaft outside. And a backing plate.
Since the rocking backing plate expands inside the shaft, the rocking backing plate itself cannot support the elastic seal member against the pressure of the shaft. For this reason, in this type of sealing device for the access port, a tightening wire for reducing the diameter of the swing backing plate and pressing its tip against the outer peripheral surface of the shield excavator or the tunnel segment via the elastic sealing member. Is wound.

[0005]

Generally, a plurality of cutting blades called bits are radially provided at the periphery of the tip of a shield machine. Generally, a step is provided between the tail portion of the shield machine and the outer peripheral surface of the tunnel segment, and the tail portion of the shield machine is in sliding contact with the outer peripheral surface of the tunnel segment and the shield machine and the outer peripheral surface of the segment. And a wire brush-like sealing means for sealing between them. Further, in general, the leading pipe provided at the tip of the buried pipe propelled by the propulsion device in the propulsion method has a slightly larger outer diameter than the buried pipe and has a tapered tip.

[0006] Therefore, the following problems occur in the above-mentioned conventional wellhead seal device for starting ports.

(1) When the swing backing plate is pressed by the peripheral edge of the shield machine and the tip of the swing backing plate is expanded, the cutting protruding from the peripheral edge of the shield machine. The blade may come into contact with the swing backing plate or the elastic seal member, and may damage the cutting blade, the swing backing plate or the elastic seal member. Further, also in the propulsion method, there is a possibility that the elastic sealing member may be damaged by the blade port at the tip of the buried pipe to be propelled, and the sealing performance may be deteriorated.

(2) The tip of the swinging backing plate is provided at the tail of the shield machine while the tip of the swinging backing plate moves from the outer periphery of the tail of the shield machine to the outer circumferential surface of the tunnel segment. There is a possibility that the abutting of the wire brush-shaped sealing means may cause an undesired deformation of the wire brush-shaped sealing means to lower the sealing function.

In addition, the above-mentioned conventional wellhead seal device for an arrival port has the following problems.

(1) Since the pressure on the excavation pit side acting on the elastic seal member acts in the direction of expanding the inner peripheral portion of the elastic seal member and the tip of the swing backing plate, the elastic seal member is moved toward the excavation pit side. In order to support the swing backing plate against the pressure, it is necessary to strongly tighten the swinging backing plate with a tightening wire,
It is difficult to ensure sufficient pressure resistance.

(2) When the elastic seal member is pressed by the peripheral edge of the shield excavator to expand the inner peripheral portion of the elastic seal member together with the distal end of the swing backing plate, the peripheral edge of the distal end of the shield excavator is used. There is a possibility that the cutting blade protruding from the elastic contact member may come into contact with the elastic seal member and damage the elastic seal member. Further, also in the propulsion method, there is a possibility that the elastic sealing member may be damaged by the blade port at the tip of the buried pipe to be propelled, and the sealing performance may be deteriorated.

Therefore, the object of the present invention is applicable to both the starting side and reaching side wellheads of leading equipment such as a shield excavator and a cutting method pipe for a propulsion method. An object of the present invention is to provide a wellhead sealing device that can prevent damage to components and is excellent in pressure-resistant sealing properties.

[0013]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 is directed to a wellhead and a pipe forming body disposed in an excavation pit formed on the ground in communication with the wellhead. Or a wellhead sealing device for sealing between the leading end and the outer peripheral surface of the leading device, wherein the elastic seal is attached to the wellhead such that the inner peripheral portion is in sliding contact with the outer peripheral surface of the conduit forming body or the leading device. The elastic seal member is disposed along a side surface of the elastic seal member opposite to the side surface on the excavation pit side, and is swingably attached to the wellhead so that the tip is expanded toward the excavation pit side; the back of the front Symbol elastic sealing member between the outer peripheral surface of the tip by expansion to the pit side in contact with the outer peripheral surface of the conduit forming body inner peripheral surface and the leading device or tube path structure of the wellhead A plurality of swinging backing plates for supporting, and a tip of the swinging backing plate, A backing plate widening means for widening to a position away from the periphery, expanding the inner peripheral portion of the elastic sealing member
Sealing member expanding means for expanding the sealing member.
The opening means is an inner peripheral surface of the wellhead and the elastic seal member.
A plurality of rings arranged in the inner peripheral portion in the circumferential direction,
An annular ring disposed on the inner peripheral surface of the wellhead and the elastic seal member
Seals that are alternately inserted into the ring provided on the inner periphery of the
A member expanding wire, and pulling the sealing member expanding wire.
The inner peripheral portion of the elastic seal member is expanded by tightening
A wellhead sealing device characterized by the above configuration is provided.

[0014] The wellhead sealing device having the above-described structure, whether provided at the wellhead on the starting equipment starting side or at the wellhead on the arrival side, has the elasticity of the pressure on the wellbore side of the wellhead. Since the inner peripheral portion of the seal member and the tip of the swing back plate act in a direction to reduce the diameter, the elastic seal member can be strongly pressure-resistant supported by the swing back plate against the pressure on the digging pit side. it can.

Further, when the wellhead sealing device is provided at the wellhead on the leading equipment starting side, when the leading equipment starts from the wellhead, the tip of the swinging backing plate is elastically sealed by the backing plate expanding means in advance. Since the front end of the leading device can be prevented from coming into contact with the swing backing plate or the elastic seal member. Also, in the case of the shield method, when the tip of the swinging backing plate moves from the outer periphery of the tail portion of the shield machine to the outer peripheral surface of the tunnel segment,
Since the tip of the swinging backing plate can be maintained at a required degree of expansion by the backing plate spreading means, the tip of the swinging backing plate is formed in a wire brush-like shape provided at the tail of the shield machine. Contact with the sealing means can be prevented.

On the other hand, when this wellhead sealing device is provided at the wellhead on the side of the leading equipment, when the leading equipment reaches the wellhead, the tip of the swinging backing plate is set in advance together with the elastic sealing member together with the backing plate expanding means. Thus, the leading device can be expanded in the direction opposite to the forward direction, so that the leading end of the leading device can be prevented from contacting the elastic seal member or the swing back plate.

Therefore, a wellhead sealing device which can be applied to either the starting device starting side wellhead or the reaching side wellhead, can prevent damage to the components of the leading device or wellhead sealing device, and is excellent in pressure-resistant sealing property. Can be provided.

Moreover, when the inner peripheral portion of the elastic seal member is required,
Or by using the seal member
The opening can be maintained, and the inner peripheral surface of the wellhead
Ring and the inner peripheral portion of the elastic seal member.
Pull the sealing member expanding wire inserted alternately through the
By tightening, the inner peripheral part of the elastic seal member can be easily
Can be expanded. Therefore, leading equipment or rocking
When the inner peripheral portion of the elastic seal member is expanded with the moving back plate
The inner peripheral portion of the elastic seal member is
Can be expanded, for example, rectangular or horizontal
Bullets attached to non-circular wellheads, such as ball-shaped
Even with a conductive seal member, it expands only with the lead device
It is possible to easily expand a part that is difficult to perform.

According to a second aspect of the present invention, in the wellhead sealing device according to the first aspect, each of the swinging backing plates is swingably attached to a fixed plate fixed to the wellhead via a hinge portion. The backing plate expanding means is provided on each swinging backing plate, and is connected to the projecting piece extending in a direction opposite to the tip of the swinging backing plate with respect to the hinge portion; and A projecting piece tightening wire, wherein the tip of the swing back plate is expanded by tightening the projecting piece tightening wire.

According to the above configuration, the tip of the swing backing plate can be easily expanded by tightening the projecting piece tightening wire connected to the projecting piece.

According to a third aspect of the present invention, in the wellhead sealing device according to the first aspect, the sealing member expanding wire is guided from the inside of the wellhead to the outside of the wellhead on the opposite side of the wellbore. A wire guide means for providing the same.

According to the above construction, the sealing member expanding wire can be guided from the inside of the wellhead to the outside of the wellhead on the opposite side of the excavation pit via the wire guiding means, so that the elastic sealing member can be expanded. The tightening operation of the seal member expanding wire can be easily performed in the work space outside the wellhead opposite to the excavation pit.

According to a fourth aspect of the present invention, there is provided a method according to the present invention, wherein a hole is formed between a well and a pipe forming body disposed in an excavation formed in the ground in communication with the well, or an outer peripheral surface of a leading device at a tip end thereof. A wellhead sealing device for sealing the wellhead, wherein the wellhead is disposed in the wellhead at an interval in a drilling direction of the wellhead, and an inner peripheral portion of the wellhead is in sliding contact with an outer peripheral surface of the pipeline forming body or the leading device. Outer and inner elastic seal members attached to the wellhead, and disposed along the side of the outer elastic seal member on the side of the excavation pit, and the tip is expanded to the side opposite to the excavation pit. Attached to the wellhead so as to be swingable, the tip is abutted on the outer peripheral surface of the leading equipment or pipeline forming body by expanding to the side opposite to the excavation pit, and the inner peripheral surface of the wellhead and the leading equipment or pipe Between the outer peripheral surface of the road forming body and the digging pit side of the outer elastic seal member. A plurality of outer swinging backing plates for supporting the surface, and the inner elastic seal member are arranged along a side surface opposite to the side surface of the digging pit, and the tip is expanded toward the digging side. Is mounted on the wellhead so as to be swingable, and the tip thereof abuts on the outer peripheral surface of the leading device or the conduit forming body by expanding to the side of the excavation pit, and the inner peripheral surface of the wellhead and the leading device or the conduit forming are formed. A plurality of inner rocking backing plates for supporting the side surface of the inner elastic seal member opposite to the side surface of the inner elastic sealing member on the side of the excavation pit, and tips of the outer and inner rocking backing plates; And an inner and outer backing plate expanding means for expanding the backing plate to a position separated from the outer periphery of the leading equipment.

The wellhead sealing device having the above-mentioned structure can be used to provide outer and inner elastic seals when necessary, whether provided at the wellhead on the starting equipment start side or at the wellhead on the leading equipment arrival side. The inside of the hermetic space defined by the inner peripheral surface of the member and the wellhead and the outer peripheral surface of the leading equipment or pipeline forming body is set to a pressure higher than the external pressure on the excavation pit side and the external pressure on the opposite side of the excavation pit. By doing so, the outer and inner elastic seal members can be firmly pressure-resistant supported by the outer and inner swing backing plates.

Further, since the front ends of the outer and inner swinging backing plates can be expanded by the backing plate expanding means together with the outer and inner elastic sealing members when necessary, the leading end of the leading device can be expanded outwardly or outwardly. Contact with the inner swing backing plate or the outer or inner elastic seal member can be prevented.
Also, in the case of the shield method, when the tip of the swinging backing plate moves from the outer periphery of the tail portion of the shield excavator at the start to the outer circumferential surface of the tunnel segment, the tip of the outer or inner swinging backing plate is Since the required degree of expansion can be maintained by the outer or inner backing plate expanding means, the tip of the outer or inner swinging backing plate has a wire brush-like shape provided at the tail of the shield machine. Contact with the sealing means can be prevented.

Therefore, the wellhead seal which can be applied to either the starting equipment start side wellhead or the arrival side wellhead, can prevent damage to the components of the leading equipment or wellhead sealing device, and can enhance the pressure resistance sealing property An apparatus can be provided.

According to a fifth aspect of the present invention, in the wellhead sealing device according to the fourth aspect , each of the outer and inner swinging backing plates can swing via a hinge portion to a fixing plate fixed to the wellhead. The outer and inner backing plate expanding means are respectively provided on each swing backing plate, and project from the hinge portion in the direction opposite to the tip of the swinging backing plate. And a protruding piece tightening wire connected to the protruding piece, and the outer and inner rocking backing plate ends are respectively expanded by tightening the outer and inner protruding piece tightening wires. It is characterized by having done.

According to the above arrangement, the tip of the outer or inner swing backing plate can be easily expanded by tightening the outer or inner projecting piece tightening wire connected to the projecting piece.

According to a sixth aspect of the present invention, in the wellhead sealing device according to the fifth aspect , the outer projecting piece tightening wire is provided at the wellhead from the inside of the wellhead to the outside of the wellhead opposite to the excavation pit. It is characterized in that wire guiding means for guiding is provided.

According to the above configuration, the outer projecting piece tightening wire can be guided from the inside of the wellhead to the outside of the wellhead opposite to the excavation pit via the wire guiding means, so that the outer swing backing plate can be moved. The tightening operation of the outer projecting piece tightening wire for expanding can be easily performed in the work space outside the wellhead opposite to the excavation pit.

Further, the invention according to claim 7 is characterized in that between the wellhead and the outer peripheral surface of the pipe forming body disposed at the excavation pit excavated and formed on the ground in communication with the wellhead or the leading equipment at the tip thereof. A wellhead sealing device, which seals an inner hollow portion of the elastic seal member having an inner hollow structure attached to the wellhead such that an inner peripheral portion thereof is in sliding contact with an outer peripheral surface of the conduit forming body or the leading device; and Located along the side of the pit,
And, the tip is swingably attached to the wellhead such that the tip is expanded to the side opposite to the excavation pit, and the tip is extended to the side opposite to the excavation pit so that the tip is the outer periphery of the leading device or the pipeline forming body. A plurality of outer rocking backing plates that abut against a surface to support the side surface of the elastic seal member on the excavation pit side between the inner peripheral surface of the wellhead and the outer peripheral surface of the leading device or the conduit forming body, The elastic seal member is arranged along the side surface opposite to the side surface on the excavation pit side, and is swingably attached to the wellhead such that the tip is expanded toward the excavation pit side, and is moved to the excavation pit side. The tip of the elastic seal member on the excavation pit side of the elastic seal member between the inner peripheral surface of the wellbore and the outer peripheral surface of the leading device or the conduit forming body by contacting the outer peripheral surface of the leading equipment or the conduit forming body by the expansion of A plurality of inner swinging backing plates for supporting the side surface opposite to the side surface; Providing wellhead seal device characterized by comprising an outer and inner backing plate spreader means is expanded end to a position away from the outer periphery of each lead instrument.

The wellhead sealing device having the above-described structure, whether provided at the wellhead on the starting equipment start side or at the wellhead on the leading equipment arrival side, allows the inside of the elastic sealing member to be used when necessary. By making the external pressure on the excavation pit side and the external pressure on the opposite side of the excavation pit higher, the elastic seal member is strongly pressure-resistant supported by the outer and inner rocking backing plates against these external pressures It is possible to do.

Further, since the outer and inner swinging backing plates can be expanded by the outer and inner backing plate expanding means together with the inner peripheral portion of the elastic seal member when necessary, the leading end of the leading device can be expanded. Can be prevented from contacting the outer or inner swinging backing plate or the elastic seal member. Also, in the case of the shield method, when the tip of the swinging backing plate moves from the outer periphery of the tail portion of the shield excavator at the start to the outer circumferential surface of the tunnel segment, the tip of the outer or inner swinging backing plate is Since the required degree of expansion can be maintained by the outer or inner backing plate expanding means, the tip of the outer or inner swinging backing plate has a wire brush-like shape provided at the tail of the shield machine. Contact with the sealing means can be prevented.

Therefore, the wellhead seal which can be applied to both the starting equipment start-side wellhead and the arrival-side wellhead, can prevent damage to the components of the leading equipment or wellhead sealing device, and can enhance the pressure resistance sealing property An apparatus can be provided.

According to an eighth aspect of the present invention, in the wellhead sealing device according to the seventh aspect , the outer and inner swinging backing plates can swing via hinge portions on fixed plates fixed to the wellhead, respectively. The outer and inner backing plate expanding means are respectively provided on each swing backing plate, and project from the hinge portion in the direction opposite to the tip of the swinging backing plate. And a protruding piece tightening wire connected to the protruding piece, and the outer and inner rocking backing plate ends are respectively expanded by tightening the outer and inner protruding piece tightening wires. It is characterized by having done.

According to the above arrangement, the tip of the outer or inner swing backing plate can be easily expanded by tightening the outer or inner projecting piece tightening wire connected to the projecting piece.

According to a ninth aspect of the present invention, in the wellhead sealing device according to the seventh aspect , the outer projecting piece tightening wire is provided at the wellhead from the inside of the wellhead to the outside of the wellhead opposite to the excavation pit. It is characterized in that wire guiding means for guiding is provided.

According to the above configuration, the outer projecting piece tightening wire can be guided from the inside of the wellhead to the outside of the wellhead opposite to the excavation pit via the wire guiding means, so that the outer rocking backing plate is provided. The operation of tightening the outer projecting piece tightening wire for expanding the opening can be easily performed in the work space outside the wellhead opposite to the excavation pit.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a wellhead sealing device in the case where the present invention is applied to a shield tunneling machine start side wellhead of a shaft.
It shows a reference example . FIG. 1 is a longitudinal sectional view of a main part of a wellhead sealing device, FIG. 2 is a perspective view showing an example of a hinged configuration of a swing backing plate and a fixed plate used in the wellhead sealing device of FIG. 1, and FIG. FIG. 2 is a side view schematically showing an arrangement state of a swing backing plate and a projecting piece tightening wire in the wellhead sealing device of FIG. 1.

First, referring to FIG. 1, a wellhead 4 whose surface is covered with a coating plate 3 is formed on a wellhead 2 of a shaft 1, and the wellhead 4 is formed between an outer wall surface and an inner wall surface of the wellhead 2. It is open. Here, the wellhead 4 has a circular cross section corresponding to the cylindrical shield machine. A plurality of anchor bolts 5 protruding from the inner wall surface of the wellhead wall 2 are buried around the inner opening end of the wellhead 4 and are arranged at regular intervals in the circumferential direction.

In FIG. 1, reference numeral 6 schematically shows a main part of a shield machine as a leading device to be launched from the wellhead 4, and reference numeral 7 designates a pipeline connected to a rear portion of the shield machine 6. Fig. 2 schematically shows a main part of a tunnel segment as a forming body. The shield machine 6 has a rotary cutter 9 at the tip of the cylindrical portion 8, and the rotary cutter 9 has a number of front excavating blades 10 and a bit projecting radially outward from the outer shape of the cylindrical portion 8. (Cutting blade) 11 and the like are provided. With this bit 11, a tunnel hole slightly larger than the outer diameter of the cylindrical portion 8 can be excavated in the ground.

The cylindrical portion 8 of the shield machine 6 has an outer diameter larger than the outer diameter of the tunnel segment 7, and the inner surface of the tail portion of the cylindrical portion 8 includes the cylindrical portion 7 and the outer peripheral surface of the tunnel segment 7. There is provided a wire brush-like sealing means 12 for sealing the gap therebetween. Generally, this sealing means 1
No. 2 can secure sealing performance by filling grease between wires. The sealing means 12 projects obliquely rearward from the inner surface of the cylindrical portion 8 toward the outer peripheral surface of the tunnel segment 7, and a part of the sealing means 12 is
It is generally arranged to be exposed from the rear end to the outside.

The wellhead 4 has a space between the inner peripheral surface of the wellhead 4 and the outer peripheral surface of a shield machine 6 or a tunnel segment 7 which is disposed in a digging pit formed in the ground in communication with the wellhead 4. An elastic sealing member 14 for sealing is attached. As shown in FIG. 2, the elastic sealing member 14 has a circular ring shape, and the inner diameter thereof is
Is set to be smaller than the outside diameter. As shown in FIG. 1, the outer peripheral portion of the elastic seal member 14 is a ring-shaped pressing plate 1.
It is fastened and fixed to the inner opening end face of the wellhead 4 by a nut 17 screwed to the anchor bolt 5 together with 5 and a plurality of fixing plates 16 described later. By expanding the inner peripheral side of the elastic seal member 14 toward the outside of the shaft, that is, the excavation pit side, the inner peripheral part of the elastic seal member 14 can be brought into close contact with the outer peripheral surface of the shield machine 6 or the tunnel segment 7. This allows the inner peripheral surface of the wellhead 4 and the shield machine 6
Alternatively, it is possible to seal between the outer peripheral surface of the tunnel segment 7.

As shown in FIG. 2 and FIG.
Is connected to a swing backing plate 18 via a hinge 19. The swing backing plate 18 is radially arranged along the side surface of the elastic seal member 14 on the inner side of the shaft, and swings to the wellhead 4 via the fixing plate 16 so that the tip is expanded toward the excavation shaft. Mounted as possible. Then, due to the expansion toward the excavation pit side, the tip abuts on the outer peripheral surface of the shield excavator 6 or the tunnel segment 7, whereby the inner peripheral surface of the wellhead 4 and the outer peripheral surface of the shield excavator 6 or the tunnel segment 7 are The back surface of the elastic seal member 14 can be pressure-resistant supported between them.

The elastic sealing member 14 with respect to the wellhead 4
The illustrated mounting structure of the swing backing plate 18 is merely an example. For example, when using an interconnected fixing plate as disclosed in Japanese Patent Application Laid-Open No. Hei 5-340184 by the present applicant, the holding plate 15 is Can be omitted. Further, a plurality of swing backing plates 18 may be swingably attached to the ring-shaped or arc-shaped fixed plate 16.
As shown in Japanese Patent Publication No. 78, an outer peripheral portion of an elastic seal member is attached to a side surface of an annular mounting plate protruding inward from an inner opening end of a wellhead on a digging pit side, and a swing backing plate is attached to the mounting plate. It is also possible to directly or indirectly swingably mount. In addition, the swing backing plate 18 in the illustrated example is swingably attached to the fixed plate 16 by a hinge portion having a hinge shaft, but the hinge portion swings using elastic deformation of an elastic joint plate. The backing plate may be capable of swinging.

Backing plate spreader means 20 is provided in [0047] swing backing plate 18. The backing plate expanding means 20 is for expanding the tip of the swinging backing plate 18 toward the excavation pit to a position separated from the outer periphery of the shield machine 6. In this example , the backing plate expanding means 20 is a protruding piece provided on each swing backing plate 18 and extending in a direction opposite to the tip of the swinging backing plate 18 with respect to the hinge portion 19. 21 and a projecting piece tightening wire 2 connected to the projecting piece 21 and wound about one round therearound.
By tightening the protruding piece tightening wire 22 to reduce the diameter of the protruding piece 21, the tip of the swing backing plate 18 can be expanded toward the excavation pit. ing. In the case of a relatively small wellhead sealing device, the tightening operation of the projecting piece tightening wire 22 can be performed manually, but in the case of a large wellhead sealing device, the tightening operation of the projecting piece tightening wire 22 is performed by, for example, a hydraulic cylinder device or the like. It is preferable to use this power.

In the illustrated example , the wire holding means is
Through hole 2 for inserting projecting piece tightening wire 22 into each projecting piece 21
3 is formed, any wire holding means may be used as long as it can hold the projecting piece tightening wire 22 so that the projecting piece tightening wire 22 does not come off from the projecting piece 21. Therefore, for example, a notch groove, A hook or the like may be provided on the protruding piece 21. The projecting piece tightening wire 22 is connected to the projecting piece 2.
It may be wound around one round (360 °) or more.

In general, the pressure P1 inside the shaft 1 (that is, the pressure on the side opposite to the shaft) is almost atmospheric pressure, but the pressure P2 on the shaft 1 is generally higher than the pressure P1 inside the shaft 1. Become. Therefore, when the wellhead sealing device having the above configuration is used, the pressure P2 on the excavation pit side acts in the direction of reducing the diameter of the inner peripheral portion of the elastic seal member 14 and the tip of the swing backing plate 18, so that the elastic seal The member 14 can be firmly pressure-resistant supported by the swing backing plate 18 against the pressure P2 on the excavation pit side.

The shield machine 6 is connected to the well 4 of the shaft 1
When the vehicle starts moving, the tip of the swing backing plate 18 can be expanded in advance by the projecting piece tightening wire 22, so that the bit (cutting blade) 11 protruding from the periphery of the tip of the shield machine 6 can be swung. The contact with the moving backing plate 18 can be prevented. Further, when the tip of the swing backing plate 18 moves from the outer periphery of the tail portion of the shield machine 6 to the outer peripheral surface of the tunnel segment 7 by further advancement of the shield machine 6, the swing backing plate 18 Since the tip can be maintained at a required expansion degree by the projecting piece tightening wire 22, the swing backing plate 1
8 can be prevented from contacting the wire brush-shaped sealing means 12 provided at the tail of the shield machine 6.

After the gap between the inner circumferential surface of the wellhead 4 and the outer circumferential surface of the tunnel segment 7 is sealed by the wellhead sealing device, the backfill material injection pipe 24 provided on the wellhead wall 2 is provided.
1 (see FIG. 1), the backfill material can be injected into the space outside the elastic seal member 14.

FIG. 4 is a longitudinal sectional view of a principal part showing another reference example in which the above-mentioned wellhead sealing device is applied to a wellhead on a side of a shaft excavation machine of a shaft. As can be seen from FIG. 4, also at the wellhead reaching the shield machine, the rocking backing plate 18 of the wellhead sealing device is disposed along the side surface of the elastic seal member 14 inside the shaft, and the tip is excavated. It is swingably attached to the wellhead 4 so as to be expanded toward the wellhead.

Therefore, also at the wellhead 4 on the side of the shield machine, the pressure on the side of the excavation pit acts in the direction of reducing the diameter of the inner peripheral portion of the elastic seal member 14 and the tip of the swinging backing plate 18. The sealing member 14 can be firmly pressure-resistant supported by the swing backing plate 18 against the pressure on the side of the excavation pit. On the other hand, when the shield machine 6 reaches the wellhead 4, the tip of the swinging backing plate 18 is expanded together with the elastic seal member 14 in advance toward the excavation pit by the projecting piece tightening wire 22 of the backing plate expanding means 20. Therefore, it is possible to prevent the bit (cutting blade) 11 or the like protruding from the peripheral edge of the tip end of the shield machine 6 from contacting the elastic seal member 14 or the swing backing plate 18.

FIGS. 5 and 6 show a first embodiment of the present invention. FIG. 5 is a longitudinal sectional view of an essential part when a wellhead sealing device is applied to a wellhead on the starting side of a shield machine. FIG. 6 is an explanatory view of an arrangement state of the seal member expanding wire shown in FIG. 5. In these figures, the same components as those in the above-mentioned reference example are denoted by the same reference numerals.

The wellhead sealing device according to the first embodiment is characterized in that it comprises a seal member expanding means 25 for expanding the inner peripheral portion of the elastic seal member 14. In this embodiment, the seal member expanding means 25 is provided with a plurality of through-holes respectively provided on the inner peripheral surface of the wellhead 4 (that is, the inner peripheral surface of the cover plate 4) and the inner peripheral portion of the elastic seal member 14. It has rings 26 and 27 and a sealing member expanding wire 28. The seal member expanding wire 28 is alternately inserted into a ring 26 provided on the inner peripheral surface of the wellhead 4 and a ring 27 provided on the inner peripheral portion of the elastic seal member 14, and the elastic seal member 14 is inserted. , And the inner peripheral portion of the elastic seal member 14 can be expanded by tightening the seal member expanding wire 28. Note that this sealing member expanding wire 2
8 may be wound around the elastic seal member 14 for one or more rounds (360 °), and a part of the inner peripheral portion of the elastic seal member 14 may be formed by a plurality of seal member expanding wires. Each can also be expanded.

Further, in the first embodiment, the shaft 1
A wire guiding means 29 for guiding the seal member expanding wire 28 from the inside of the wellhead 4 to the inside of the shaft 1 is provided on the wellhead wall 2. To expand the inner peripheral portion of the elastic seal member 14, both ends of the seal member expanding wire 28 may be pulled.
, And only the other end may be pulled. Therefore, both ends of the sealing member expanding wire 28 can be guided into the shaft 1 by the wire guiding means 29,
Only one end of the seal member expanding wire 28 may be guided into the shaft 1.

[0057] The wellhead sealing device of the first embodiment, the
Similarly to the reference example , the present invention can be applied to the shield tunnel start-side wellhead and the shield tunnel arrival-side wellhead.
5, the shield excavator 6 or the swing backing plate 1 can be maintained at a desired degree of expansion.
When the inner peripheral portion of the elastic seal member 14 is expanded at 8,
The operation of expanding the inner peripheral portion of the elastic seal member 14 can be assisted by the seal member expanding means 25. Therefore,
The elastic seal member 14 can be easily and reliably expanded. Further, as shown in FIGS. 7A and 7B, even in the case of the elastic seal member 14 which is attached to a non-circular wellhead such as a rectangular or horizontal bar-shape, for example, It is possible to easily expand a portion that is difficult to expand only with a shield machine, such as a corner portion or a constriction at the center of the horizontal bar-shaped elastic seal member 14.

Further, in the wellhead sealing device of the first embodiment, a ring 26 provided on the inner peripheral surface of the wellhead 4 and a ring 27 provided on the inner peripheral portion of the elastic seal member 14 alternately. The inner peripheral portion of the elastic seal member 14 can be easily expanded by tightening the seal member expanding wire 28 inserted through the elastic member. Further, since the sealing member expanding wire 28 can be guided into the shaft 1 from the inside of the wellhead 4 through the wire guiding means 29, the tightening operation of the sealing member expanding wire 28 for expanding the elastic seal member 14 is performed. Can be easily performed in the shaft 1.

FIG. 8 is a longitudinal sectional view of a main part of a wellhead sealing device according to a second embodiment of the present invention. In the figure, the same components as those in the above reference example are denoted by the same reference numerals.

The wellhead sealing device according to the second embodiment is attached to the wellhead 4 of the wellhead 1 at intervals in the inside and outside directions of the wellhead 1 and the inner peripheral surface of the wellhead 4 and the shield machine 6 or the tunnel segment 7. Outer and inner elastic seal members 14A and 14B for sealing between the outer peripheral surface, outer and inner elastic seal members 14A and 14B, the inner peripheral surface of the wellhead 4, and the outer peripheral surface of the shield machine 6 or the tunnel segment 7. Pressurizing means 30 for keeping the inside of the hermetic space defined by the pressure higher than the external pressure, and disposed along the side of the outer elastic seal member 14A on the side of the excavation pit, and the tip thereof is formed with the excavation pit. Are a plurality of outer swinging backing plates 1 which are swingably attached to the wellhead 4 so as to be expanded on the opposite side, that is, inside the shaft.
8A and the inner elastic seal member 14B are disposed on the inner side surface of the shaft (that is, the side surface opposite to the side surface of the excavation pit), and the tip of the inner elastic seal member 14B is swung by the wellhead 4 so as to be expanded toward the excavation side. A plurality of movably mounted inner swinging backing plates 18B
And A gas or liquid such as air, a resin, or the like can be press-fitted into the hermetic space by the pressurizing means 30, but if an elastic filler is press-fitted and sealed, the sealing and elasticity are rich. A wellhead sealing device can be obtained.

The outer rocking backing plate 18A contacts the outer peripheral surface of the shield excavator 6 or the tunnel segment 7 at the tip thereof in a state where the outer rocking backing plate 18A is expanded inside the shaft, so that the inner peripheral surface of the wellhead 4 and the shield excavator are 6 or the outer peripheral surface of the tunnel segment 7 can support the side surface of the outer elastic seal member 14A on the excavation pit side with pressure. Also, the inner swing backing plate 18
B is a shield excavator 6 with the tip extended to the excavation pit side.
Alternatively, by contacting the outer peripheral surface of the tunnel segment 7, the inner elastic sealing member 14B is formed between the inner peripheral surface of the wellhead 4 and the outer peripheral surface of the shield machine 6 or the tunnel segment 7.
Of the shaft can be pressure-resistant.

Further, the wellhead sealing device of the second embodiment is
Outer and inner backing plate expanding means 20A and 20B are provided for expanding the ends of the outer and inner swinging backing plates 18A and 18B to positions separated from the outer periphery of the shield machine 6 respectively. The outer and inner rocking backing plates 18
A and 18B are swingably attached to a fixing plate 16 fixed to the wellhead 4 via hinge portions 19A and 19B, similarly to the above-described reference example, and outer and inner backing plate expanding means 20A are provided. , 20B respectively correspond to the respective swing backing plates 18A, 1A.
8B, protruding pieces 21A, 21B extending in the opposite direction to the tips of the swing back plates 18A, 18B with respect to the hinge portions 19A, 19B, and protruding piece tightening wires connected to the protruding pieces 21A, 21B, respectively. 22A and 22B. Therefore, the outer and inner projecting piece tightening wires 2
By tightening the 2A, 22B and reducing the diameter of the protruding pieces 21A, 21B, the distal ends of the outer and inner swing backing plates 18A, 18B can be expanded, respectively, as in the first embodiment.

Further, in the wellhead sealing device of the second embodiment, the outer projecting piece tightening wire 2 is attached to the shaft wall 2 of the shaft 1.
Wire guide means 29 for guiding 2A from the inside of the wellhead 4 to the inside of the shaft 1 (that is, the outside of the wellhead opposite to the excavation pit) is provided.

The wellhead sealing device of the second embodiment can be provided either at the wellhead on the starting side of the shield machine or at the wellhead on the reaching side of the shield machine.
When necessary, the pressurizing means 30 moves the inside of the hermetic space defined by the outer and inner elastic seal members 14A, 14B, the inner peripheral surface of the wellhead 4 and the outer peripheral surface of the shield machine 6 or the tunnel segment 7 into the shaft. (That is, the external pressure on the side opposite to the excavation pit) P1 and the pressure P3 higher than the external pressure P2 on the excavation pit side, thereby causing the outer and inner elastic seal members 14A and 14B to oscillate between the outer and inner sides. The backing plates 18A and 18B can firmly support the pressure resistance.

The outer and inner swing backing plates 18A,
The front end of the shield excavator 6 can be extended by the backing plate expanding means 20A, 20B together with the outer and inner elastic seal members 14A, 14B when necessary. The cutting blade 11 can be prevented from contacting the outer or inner swing backing plates 18A, 18B or the outer or inner elastic seal members 14A, 14B. In addition, the outer or inner swing backing plate 18
Even when the tips of A and 18B move from the outer periphery of the tail portion of the shield machine 6 to the outer peripheral surface of the tunnel segment 7 at the time of starting, the tips of the outer or inner swing backing plates 18A and 18B are connected to the outer or inner side. Since the required degree of expansion can be maintained by the backing plate expanding means 20A, 20B, the tip of the outer or inner swinging backing plate 18A, 18B is attached to the shield excavator 6
Can be prevented from contacting the wire brush-shaped sealing means 12 provided at the tail portion of the wire.

In the second embodiment, the outer or inner swing backing plates 18A, 18B are tightened by tightening the outer or inner projecting piece tightening wires 22A, 22B connected to the projecting pieces 21A, 21B. Can be easily expanded. Further, since the outer projecting piece tightening wire 22A can be guided from the inside of the wellhead 4 to the inside of the shaft 1 via the wire guide means 29, the outer projecting piece for expanding the outer swing backing plate 18A can be provided. Single tightening wire 2
The tightening operation of 2A can be easily performed in the shaft 1.

FIG. 9 shows a third embodiment of the present invention. In the figure, the same reference numerals are given to the same components as those in the first and third embodiments.

The wellhead sealing device of the third embodiment is
The outer and inner elastic seal members 14A in the embodiment,
Instead of 14B, the inner peripheral surface of the wellhead 4 and the shield machine 6
Alternatively, the second embodiment differs from the second embodiment in that an elastic seal member 14C having an internal hollow structure for sealing between the tunnel segment 7 and the outer peripheral surface is used, and the other configuration is the same as the second embodiment. The elastic seal member 14C of the third embodiment has a substantially C-shaped cross section, and a pair of inner and outer peripheral ends are attached to the wellhead 4. Also, an elastic sealing member 1 having a hollow structure
The inside of the 4C can be filled with, for example, a pressurized gas or an elastic material by the pressurizing means 30.

Therefore, the wellhead sealing device of the third embodiment can be provided at the wellhead on the starting side of the shield machine, as well as at the wellhead on the arrival side of the shield machine, as in the second embodiment. Even when the elastic seal member 14C is provided, the inside of the elastic seal member 14C having the internal hollow structure is set to a pressure P3 higher than the internal pressure P1 inside the shaft and the external pressure P2 on the side of the excavation pit when necessary, so that the elastic seal member 14C Further, it is possible to strongly support the pressure with the inner swing backing plates 18A and 18B.

The outer and inner swing backing plates 18A, 18A,
Since the front end of the shield excavator 6 can be expanded by the backing plate expanding means 20A and 20B together with the inner peripheral portion of the elastic seal member 14C when necessary, the bit (cutting edge) 11) can be prevented from contacting the outer or inner swing backing plates 18A, 18B and the elastic seal member 14C. Also, when the tips of the outer or inner rocking backing plates 18A and 18B move from the outer circumference of the tail portion of the shield machine 6 to the outer circumferential surface of the tunnel segment 7 at the time of starting, the outer or inner rocking backing plates 18A and 18B also move. Board 18
A, 18B the outer or inner backing plate expanding means 20
A, 20B can maintain the required degree of expansion, so that the ends of the outer or inner swing backing plates 18A, 18B are provided at the tail of the shield machine 6 in the form of wire brush-like sealing means 12. Contact can be prevented.

Also in the third embodiment, the outer or inner swing backing plates 18A, 18B are tightened by tightening the outer or inner projecting piece tightening wires 22A, 22B connected to the projecting pieces 21A, 21B. Can be easily expanded. Further, since the outer projecting piece tightening wire 22A can be guided from the inside of the wellhead 4 to the inside of the shaft 1 via the wire guide means 29, the outer projecting piece for expanding the outer swing backing plate 18A can be provided. Single tightening wire 2
The tightening operation of 2A can be easily performed in the shaft 1.

FIG. 10 shows a fourth embodiment of the present invention. In the figure, the reference example , the second embodiment and the third embodiment are shown.
The same components as those of the embodiment are denoted by the same reference numerals.

[0073] wellhead seal device of the fourth embodiment, third
The third embodiment differs from the third embodiment in that a tubular elastic hollow member 14D having an internal hollow structure is used instead of the elastic seal member 14C having an internal hollow structure having a substantially C-shaped cross section in the embodiment. This is the same as the third embodiment. The elastic seal member 14D of the fourth embodiment can be easily fixed to the inner peripheral surface of the wellhead 4 with an adhesive or the like. A pressing means 30 is provided inside the elastic sealing member 14D having a hollow structure.
Thereby, for example, it is possible to fill a pressurized gas or an elastic material.

Therefore, the wellhead sealing device of the fourth embodiment can be provided at the wellhead on the starting side of the shield machine, as in the above-described third embodiment, and also at the wellhead on the arrival side of the shield machine. Even when the elastic seal member 14D is provided, the elastic seal member 14D having the internal hollow structure is set to a pressure P3 higher than the internal pressure P1 inside the shaft and the external pressure P2 on the side of the excavation pit when necessary, so that the elastic seal member 14D Further, the pressure can be firmly supported by the inner swing backing plates 18A and 18B. Since the elastic seal member 14D has a tubular shape, the elastic seal member 14C of the fourth embodiment is formed.
Higher sealing performance can be ensured.

Although the illustrated embodiment has been described above, the present invention is not limited to only the above embodiment.
Various modifications can be made to the components within the scope of the invention described in the claims. For example, in the second to fourth embodiments shown in FIGS. 8 to 10, the elastic seal members 14A, 14B, 14C, and 14D are also provided.
Can be provided with a sealing member expanding means for expanding the sealing member.

The wellhead sealing device according to the present invention is applicable not only to wellheads to which the shield method is applied, but also to wellheads to which, for example, the propulsion method is applied. In this case, a tapered tip tube is used instead of the shield excavator as the leading device, and a buried tube, that is, a tubular body, is used instead of the tunnel segment as the conduit forming body. Furthermore, the wellhead sealing device according to the present invention can be used not only for wellheads formed on the wellheads of vertical shafts, but also for wellheads for excavating branch tunnels formed on the wellheads of tunnels, or for wellboring formed on the ground surface. The present invention can be similarly applied to a wellhead or the like.

[0077]

As is apparent from the above description, according to the present invention, the present invention can be applied to either the starting equipment entrance port or the arrival port entrance, and damage to components of the leading equipment or the entrance sealing device. And a wellhead sealing device excellent in pressure-resistant sealing performance can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a reference example of a wellhead sealing device in the case where the present invention is applied to a shield well starter side wellhead of a shaft.

FIG. 2 is a perspective view showing an example of a hinged configuration of a swing backing plate and a fixed plate used in the wellhead sealing device of FIG. 1;

FIG. 3 is a side view schematically showing an arrangement state of a swing backing plate and a projecting piece tightening wire in the wellhead sealing device of FIG. 1;

FIG. 4 is a vertical sectional view of a main part showing another reference example in a case where the wellhead sealing device shown in FIG. 1 is applied to a wellhead on the side of a shaft excavation machine of a shaft.

FIG. 5 is a vertical sectional view of a main part of a wellhead sealing device showing a first embodiment when the present invention is applied to a wellhead on which a shield excavator is started.

FIG. 6 is an explanatory view of an arrangement state of the seal member expanding wire shown in FIG. 5;

FIGS. 7A and 7B are schematic explanatory views showing modified examples of the shape of the elastic seal member in the first embodiment.

FIG. 8 is a longitudinal sectional view of a main part of a wellhead sealing device showing a second embodiment in a case where the present invention is applied to a wellhead on a shield excavator starting side.

FIG. 9 is a longitudinal sectional view of a main part of a wellhead sealing device showing a third embodiment when the present invention is applied to a wellhead on a shield excavator starting side.

FIG. 10 is a vertical sectional view of a main part of a wellhead sealing device showing a fourth embodiment in a case where the present invention is applied to a wellhead on a shield excavator starting side.

[Explanation of symbols]

 Reference Signs List 1 shaft 2 shaft wall 4 wellhead 6 shield excavator (leading equipment) 7 tunnel segment (pipe forming body) 11 bit (cutting blade) 12 wire brush-shaped sealing means 14, 14A, 14B elastic sealing member 14C Elastic seal member 14D Elastic seal member having an internal hollow structure 16, 16A, 16B Fixed plate 18, 18A, 18B Swing back plate 19 Hinge portion 20, 20A, 20B Back plate expanding means 21, 21A, 21B Projecting piece 22 , 22A, 22B Projection piece tightening wire 24 Backfill material injection pipe 25, 25A, 25B Seal member expanding means 26, 27 Ring circulation 28 Seal member expanding wire 29 Wire guiding means 30 Pressing means

Claims (9)

(57) [Claims] An excavation is formed in a ground by communicating with the wellhead and the wellhead.
Pipe formation body or the tip of
A wellhead sealing device that seals between the outer peripheral surface of the leading equipment
And the inner peripheral portion is in sliding contact with the outer peripheral surface of the conduit forming body or the leading device.
Sealing member attached to the wellhead as described above, and a side surface of the elastic sealing member opposite the side surface on the excavation pit side
And the tip is expanded toward the excavation pit
To the excavation pit side
The tip of the pipe contacts the outer peripheral surface of the pipe forming body
The inner peripheral surface of the wellhead and the outer peripheral surface of the leading device or pipe line forming body
BetweenIn frontMultiple swings supporting the back of the elastic seal member
A backing plate, and a tip of the swing backing plate is separated from an outer periphery of the leading device.
Backing plate expanding means to expand to a position, A seal member expansion for expanding an inner peripheral portion of the elastic seal member.
And opening means, The seal member expanding means includes an inner peripheral surface of the wellhead and the
Disposed in the circumferential direction on the inner peripheral part of the elastic seal member
A plurality of loops, and a loop provided on the inner peripheral surface of the wellhead and
Alternately with the ring provided on the inner periphery of the elastic seal member.
A sealing member expanding wire inserted therethrough;
By tightening the material expanding wire, the inside of the elastic seal member
It is characterized by expanding the circumference Wellhead Sea
Device. 2. The swing backing plate is mounted on a fixing plate fixed to the wellhead via a hinge so as to be swingable, and the backing plate expanding means includes a swinging backing plate. A projecting piece provided on the plate and extending in a direction opposite to a tip of the swinging backing plate with respect to the hinge portion, and a projecting piece tightening wire connected to the projecting piece; 2. The wellhead sealing device according to claim 1, wherein the tip of the swing backing plate is expanded by tightening. 3. The wellhead is provided with wire guide means for guiding the sealing member expanding wire from the inside of the wellhead to the outside of the wellhead opposite to the excavation pit. Item 7. The wellhead sealing device according to Item 1 . 4. A wellhead sealing device for sealing between a wellhead and an outer peripheral surface of a pipe forming body or a leading device at a tip thereof which is disposed in a wellbore excavated and formed in the ground in communication with the wellhead. An outer portion which is disposed in the wellhead at an interval in a direction in which the wellhead is drilled, and which is attached to the wellhead such that an inner peripheral portion thereof is in sliding contact with an outer peripheral surface of the pipeline forming body or the leading device. And an inner elastic seal member, which is disposed along the side of the outer elastic seal member on the side of the excavation pit, and is swingably attached to the wellhead such that the tip is expanded to the side opposite to the excavation pit. The tip is in contact with the outer peripheral surface of the leading equipment or the conduit forming body by the expansion to the side opposite to the excavation pit, and the inner peripheral surface of the wellhead and the outer peripheral surface of the leading equipment or the conduit forming body are separated. A plurality of outer rockers supporting a side of the outer elastic seal member on the side of the pit. A backing plate, which is disposed along a side surface of the inner elastic seal member opposite to the side surface of the excavation pit, and is swingably attached to the wellhead such that a tip is expanded toward the excavation pit side. The tip is brought into contact with the outer peripheral surface of the leading equipment or the conduit forming body by expanding to the side of the excavation pit, and the inner peripheral surface of the wellhead and the outer peripheral surface of the leading equipment or the conduit forming body are in contact with each other. A plurality of inner rocking backing plates for supporting the side surface of the inner elastic seal member opposite to the side surface on the side of the excavation pit; and separating the tips of the outer and inner rocking backing plates from the outer periphery of the leading equipment, respectively. A wellhead sealing device comprising outer and inner backing plate expanding means for expanding to a position. 5. The outer and inner swinging backing plates are swingably attached to a fixing plate fixed to the wellhead via a hinge portion, and the outer and inner swinging backing plates are expanded. A means is provided on each swing backing plate, and a projecting piece extending in a direction opposite to a tip of the swinging backing plate with respect to the hinge portion, and a projecting piece tightening wire connected to the projecting piece. The wellhead sealing device according to claim 4, wherein the outer and inner swinging backing plates have respective ends that are expanded by tightening the outer and inner protruding piece tightening wires. 6. The wellhead is provided with wire guiding means for guiding the outer projecting piece tightening wire from inside the wellhead to outside the wellhead on the side opposite to the excavation pit. The wellhead sealing device according to claim 5 . 7. A wellhead sealing device for sealing between a wellhead and an outer peripheral surface of a leading end device or a pipe line forming body disposed in a wellbore excavated and formed on the ground in communication with the wellhead. An elastic seal member having an internal hollow structure attached to the wellhead such that an inner peripheral portion thereof is in sliding contact with an outer peripheral surface of the conduit forming body or the leading device, and along a side surface of the elastic seal member on the side of the excavation pit. Is arranged and swingably attached to the wellhead such that the tip is expanded on the side opposite to the excavation pit, and the tip is formed on the side opposite to the excavation pit so that the tip is formed by the leading equipment or conduit. A plurality of outer swinging backing abutments for supporting the side surface of the elastic seal member on the side of the excavation pit between the inner peripheral surface of the wellhead and the outer peripheral surface of the leading device or the conduit forming body in contact with the outer peripheral surface of the body; Plate, along the side surface of the elastic seal member opposite to the side surface of the excavation pit. And is swingably attached to the wellhead such that the tip is expanded toward the excavation pit side, and the tip is brought into contact with the outer peripheral surface of the leading equipment or the pipe line forming body by expanding to the excavation pit side. A plurality of inner rocking backing plates that contact and support the side of the elastic seal member opposite to the side of the excavation pit between the inner peripheral surface of the wellhead and the outer peripheral surface of the leading equipment or the conduit forming body; A wellhead sealing device, comprising: outer and inner backing plate expanding means for expanding the ends of the outer and inner swinging backing plates to positions separated from the outer periphery of the leading device, respectively. . 8. The outer and inner backing plate expansion means, wherein the outer and inner swinging backing plates are respectively swingably attached to a fixing plate fixed to the wellhead via a hinge portion. A means is provided on each swing backing plate, and a projecting piece extending in a direction opposite to a tip of the swinging backing plate with respect to the hinge portion, and a projecting piece tightening wire connected to the projecting piece. 8. The wellhead seal device according to claim 7, wherein the outer and inner swinging backing plates have respective ends expanded by tightening the outer and inner projecting piece tightening wires. 9. The wellhead is provided with wire guide means for guiding the outer projecting piece tightening wire from the inside of the wellhead to the outside of the wellhead opposite to the excavation pit. The wellhead sealing device according to claim 7 .