JPH0842288A - Shield excavator and seal method thereof - Google Patents

Abstract

PURPOSE:To prevent the abrasion in a sliding section of a cutter seal or the incursion of earth, etc., from the sliding section by supplying hard grease to seal gaps in the front of the cutter seal, and preventing the incursion of powder of excavated earth into the seal gaps. CONSTITUTION:Hard grease over No.3 of density is injected into seal gaps 16c and 17c of the front end element in advance before the start of a shield excavator, and entrance side openings 30a and 31a are closed with plugs to start the shield excavator. After that, in the case ground in the ground improvement area is excavated, the incursion of powder of excavated earth including cement into the seal gaps 16c and 17c from the front end of the shield main body 1 is prevented. No influence is given on the drive of a cutter because of non-solidified characteristics of the hard grease. According to the constitution, even if the shield excavator excavates the ground improvement area, the solidification of cement powder or the bad influence on the drive of the cutter and heat caused by friction of a ringshaped seal section 6 with other things are prevented, and the cutter can be smoothly driven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield machine having a non-center shaft support system in which a cutter head is not supported by a center shaft as a rotary drive shaft but is supported by an outer peripheral portion or an intermediate portion of the cutter head. The structure and sealing method of the cutter sealing device for sealing the excavated sand from the front end of the main body so as not to enter the main body are improved.

[0002]

2. Description of the Related Art Shield excavators for excavating underground pits such as tunnels are roughly classified from the point of a method of supporting a cutter head, and a type in which a center portion of the cutter head is supported by a center shaft as a rotary drive shaft. Of the center shaft supporting type shield machine, and the non-center shaft supporting type shield machine of the type in which the cutter head is not supported by the center shaft but the outer peripheral portion or the intermediate portion thereof is supported by the cutter supporting member. be able to. Regarding the non-center shaft support type shield machine, as a typical example, a peripheral support type shield machine that supports the outer peripheral portion of the cutter head with a cylindrical body having substantially the same shape as the shield body, the outer periphery of the cutter head. A peripheral beam support type shield excavator that supports a portion with a plurality of beam members, and an intermediate beam support type shield excavator that supports an intermediate portion between the central portion and the outer peripheral portion of the cutter head with a plurality of beam members. it can. In such a shield machine with a non-center shaft support system, the cutter head is rotatably supported on the shield body without relying on the center shaft.
A cutter seal device is provided to seal the excavated earth and sand from the front end of the shield body so that the excavated soil does not enter the body.

The present invention is intended to improve the structure of the cutter sealing device and the sealing method for this part in such a shield machine.
The structure of each of the peripheral support type, outer peripheral beam support type, and intermediate beam support type shield machine and its cutter seal device will be described below with reference to FIGS. 13 to 20. 13: is a figure which shows an example of the peripheral support type shield machine conventionally used, (a) is a front view, (b) is a longitudinal cross-sectional view, FIG. 14 is the cutter regarding the shield machine of FIG. Enlarged vertical sectional view of the sealing device, FIG.
5 is an enlarged vertical cross-sectional view of the cutter sealing device for the shield machine of FIG. 13, which is a sectional view taken with the phase in the circumferential direction changed from that in FIG. 14, and FIG. 16 is a conventional peripheral beam support type shield. It is a figure which shows an example of an excavator, (a)
Is a front view, (b) is a vertical sectional view, FIG. 17 is a view showing an example of a conventionally used intermediate beam supporting type shield machine, (a) is a front view, (b) is a vertical sectional view , FIG. 18
17 is an enlarged vertical sectional view of the cutter sealing device for the shield machine of FIG. 17, and FIG. 19 is an enlarged vertical sectional view of the cutter sealing device for the shield machine of FIG. FIG. 20 is a vertical cross-sectional view of a construction site for explaining a method of excavation by a shield machine, showing a starting preparation state, and FIG. 21 is a vertical cross-sectional view of a construction site similar to FIG. FIG. 22 is a view showing a state immediately after the shield machine is started, and FIG. 22 is a vertical sectional view of a construction site similar to FIG. 20, showing a state in which the shield machine is in the process of being excavated.

First, referring to FIG. 13, the structure of a conventionally supported peripheral excavator type shield excavator will be described. In FIG. 13, 1 is a shield main body of the shield excavator, 2 is a cutter of the shield excavator, 3 Is a cutter head that forms the ground cutting portion of the cutter 2, 3a is a boss that forms the center of the cutter head 3, 3b is a ring-shaped cutter outer peripheral frame that forms the outer periphery of the cutter head 3, and 3c is a cutter outer peripheral frame 3b It is a cutas pork that connects the boss 3a and the boss 3a. The cutter 2 is composed of a cutter head 3 and a cutter support member, which will be described later. The cutter head 3 has a skeleton formed by a cutter outer peripheral frame 3b and a cutas pork 3c and is provided in front of the shield body. A cutter bit 4a is attached to the cutter outer frame 3b at predetermined intervals in the circumferential direction, and a large number of cutter teeth 4b and cutter bits 4c are attached to the cutas pork 3c. Reference numeral 5 denotes a cutter supporting cylinder formed to have substantially the same diameter as that of the shield body 1 for supporting the outer peripheral portion of the cutter head 3, 6 denotes an annular seal portion provided at the rear portion of the cutter supporting cylinder 5, and the cutter supporting member is It is composed of the annular seal portion 6 and the cutter support cylinder 5 as the cutter support body. The cutter supporting member supports the outer peripheral portion of the cutter head at the front end portion, and connects the rear end portion to a cutter driving device described later to transmit the power thereof to the cutter head. Reference numeral 7 is an annular seal portion receiver that forms an annular space for mounting the annular seal portion 6, 8 is a cutter seal device including the annular seal portion 6 and the annular seal portion receiver 7, and 9a is an outer peripheral portion of the annular seal portion 6. The outer cutter seal 9b is attached to the inner cutter seal 9b, and the inner cutter seal 9b is attached to the inner peripheral portion of the annular seal portion 6. The outer cutter seal 9a and the inner cutter seal 9b function to prevent excavated earth and sand from invading the bearing portion of the cutter 2, as described later. The configurations of the cutter seal device 8 and its related parts will be described later in detail with reference to FIGS. 14 and 15.

Reference numeral 10 denotes a partition wall provided in the shield body 1 so as to partition an outer space serving as an excavation chamber and an inner space serving as a working chamber, and a cutter driving device 11 for decelerating and driving the cutter head 3. The cutter driving device 11 includes a hydraulic motor 11a for driving the cutter, a pinion 11b directly connected to the shaft of the hydraulic motor 11a, and a slewing bearing 11c meshing with the pinion 11b. The slewing bearing 11c has a ring-like shape and has inner teeth formed on its inner peripheral portion so as to mesh with the pinion 11b, and constitutes a reduction gear mechanism together with the pinion 11b. The reduction gear mechanism including the pinion 11b and the slewing bearing 11c reduces the rotation of the motor 11a and transmits it to the cutter head 3 through the cutter support member. 12 is a mud additive injection part for injecting mud additive into excavated soil to generate mud, 12a is a mud additive injection port of the mud additive injection part 12, 13 is mud rotating according to the rotation of the cutter head Rotating shaft of agent injection part 12, 14
Is a rotary joint for allowing the mud additive supplied from a pump (not shown) to be fed into the passage inside the rotary shaft 13 when rotating, and 15 is a soil discharge for carrying and discharging excavated soil It is a screw conveyor as a device. The rotary shaft 13 of the sludge injection unit 12 is provided especially for supplying the sludge, and supports the cutter head 3 and transmits the power of the cutter driving device 11 to the cutter head 3. Since it does not work, it is different from the center shaft as the rotary drive shaft.

Next, referring to FIGS. 14 and 15, the structure of the cutter seal device 8 and its related parts will be described in detail. The annular seal portion 6 provided at the rear portion of the cutter support cylinder 5 is
A hollow member having a rectangular cross section is formed into a ring shape having an outer diameter slightly smaller than the inner diameter of the shield body 1, and a swivel ring 11c is concentrically attached to the rear end portion. On the other hand, the shield body 1 has a seal portion outer peripheral receiving portion 7a and a seal portion inner peripheral receiving portion 7 provided concentrically with the seal portion outer peripheral receiving portion 7a.
b and the sealing portion receiving and shielding portion 7 for shielding the rear end opening between them
The annular seal portion receiver 7 is formed by c and an annular space for mounting the above-mentioned annular seal portion 6 is formed between the seal portion outer circumference receiving portion 7a and the seal portion inner circumference receiving portion 7b. The annular seal portion 6 is composed of a ring-shaped body having a thickness slightly smaller than the gap size of the annular space, and is mounted in the annular space together with the turning ring 11c attached to the rear end portion. In this way, when the annular seal portion 6 is mounted in the annular space of the annular seal portion receiver 7, the outer seal gap 16 and the inner seal gap 17 are formed between them. The excavated earth and sand enter the inside of the seal gap 16c at the front end portion in front of the cutter seal 9a and the seal gap 17c at the front end portion in front of the cutter seal 9b and enter the inside when the shield excavator is excavating. Although the pinion 11b will be damaged, the cutter seal 9a and the cutter seal 9b prevent such intrusion of excavated soil. The swivel ring 11c attached to the rear end portion of the annular seal portion 6 can be engaged with the pinion 11b through an opening (not shown) provided in the seal portion inner peripheral receiving portion 7b. A plurality of outer cutter seals 9a and inner cutter seals 9b are attached to the outer peripheral portion and the inner peripheral portion of the annular seal portion 6, respectively, to seal the outer seal gap 16 and the inner seal gap 17. Reference numerals 18a and 18b respectively shown in FIG. 14 and FIG. 15 denote outer seal greasing pipes for supplying lubricating grease to the seal gaps 16a and 16b between the adjacent outer cutter seals 9a, and 19 denotes an adjacent inner cutter seal. An inner seal greasing pipe for supplying lubricating grease to the seal gap 17a between the 9a, 20
a and 20b are grease supply passages for lubrication on the outer seal side connected to the outer seal greasing pipes 18a and 18b, respectively.
Is a lubricating grease supply passage on the inner seal side connected to the inner seal greasing pipe 19, and 22a and 22b communicate with the lubricating grease supply passages 20a and 20b on the outer seal side, respectively, to communicate with the seal gaps 16a and 16b. The lubricating grease communication port on the outer seal side formed as described above, and 23 communicates with the lubricating grease supply passage 21 on the inner seal side.
7a is a lubricating grease communication port on the inner seal side formed so as to communicate with 7a. The lubrication grease supply passages 20a and 20b on the outer seal side and the lubrication grease supply passage 21 on the inner seal side are respectively provided in the seal portion outer peripheral receiving portion 7a and the seal portion inner peripheral receiving portion 7b which form the annular seal portion receiving portion 7. Seal gaps 16a and 16b formed in the front-rear direction and between three adjacent cutter seals 9a in the cutter seal device.
And a seal gap 1 between two adjacent cutter seals 9b
7a, the lubricating grease communication ports 22a, 22 on the outer seal side
The lubricating grease is supplied through b and the lubricating grease communication port 23 on the inner seal side. The lubricating grease supply passages 20a, 20b on the outer seal side are formed in the seal portion outer peripheral receiving portion 7a by changing the phase in the circumferential direction, as is apparent from the drawings separately shown in FIGS. 14 and 15. There is. Since the lubricating grease supply passage 19 on the inner seal side has only one seal gap between the adjacent cutter seals 9b,
Although such a configuration is not adopted, when there are a plurality of such seal gaps, the lubricating grease supply passages on the inner seal side will naturally be formed by changing the phase in the circumferential direction.

The structure of the peripheral support type shield machine has been described above. Next, the structure of the peripheral beam support type shield machine conventionally used will be described with reference to FIG. In FIG. 16, 5a is the cutter head 3.
A beam for supporting the outer peripheral portion of the cutter as a main body of the cutter supporting portion that supports the outer peripheral portion of the cutter head, the front portion of which is attached to the rear surface of the outer peripheral portion of the cutter head 3, and the annular seal portion 6 is provided at the rear portion. A plurality of such beams 5a for supporting the outer periphery of the cutter are provided along the outer periphery of the cutter head 3, and together with the annular seal portion 6 constitute a cutter supporting member. As described above, the peripheral beam support type shield machine has a slight difference in the support method of the cutter head 3 compared with the peripheral support type shield machine, but it is composed of the annular seal portion 6 and the annular seal receiver 7. The structure of the cutter seal device 8 thus constructed is basically the same as that of the peripheral support type shield machine shown in FIGS. 14 and 15.

Finally, the structure of a conventionally used intermediate beam supporting type shield machine is shown in FIGS.
It will be described based on. In these figures, 5b is a beam for supporting the middle of the cutter as the main body of the cutter supporting part for supporting the middle of the central part and the outer peripheral part of the cutter head 3.
The front portion is attached to the rear surface of the middle portion of the cutter head 3, and the annular seal portion 6 is provided on the rear portion. A plurality of such beams 5b for supporting the cutter intermediate are provided along an arc portion concentric with the outer periphery of the cutter head 3, and constitute a cutter supporting member together with the annular seal portion 6. On the other hand, as shown in FIG. 18, the cutter seal device 8 is basically the same in structure as the cutter seal device of the shield excavator of the peripheral support type or the peripheral beam support type described above, but the annular seal part As shown in FIG. 17, the receiver 7 is located at an intermediate position between the center and the inner peripheral surface of the shield body 1 by a pair of partition walls 10a and 10b for supporting the annular seal portion which are projected toward the inside of the shield body 1. Is installed.

A method of excavating the natural ground using the various types of shield excavators described above will be described with reference to FIGS. 20 to 22. In the case of attempting to excavate the natural mass 40 with the shield excavator. Provides a starting shaft 41 in the ground 40 which is the starting point of the excavation. A starting entrance portion 43 is formed on a wall surface 42 of the starting shaft 41, and an entrance packing 44 is attached thereto. In addition, a starting frame 45 is installed in the starting shaft 41, and the shield machine is mounted on the starting frame 45. After doing this kind of preparation work,
When the shield machine is propelled toward the start entrance 43,
The shield machine passes through the entrance packing 44 and reaches the mirror 46, which is the starting point of the excavation, and starts excavation of the natural ground in the state as shown in FIG.

By the way, when a shield machine excavates an underground pit, there is a case where the influence of the underground pit cannot be exerted on the ground due to the existence of a structure above the excavation route. In such a case, conventionally, a method called a ground improvement method has been used in combination with such a shield method. In this ground improvement method, the ground improvement material for hardening and strengthening the ground is filled in the ground in an area where the influence of underground digging must not be exerted on the ground, and the ground is made strong and strong. It is a construction method to be improved. The ground improvement area 47 to which such a ground improvement method is applied may be an area where the starting shaft 47 is installed as shown in FIG. 21 or a starting area as shown in FIG. When implementing the ground improvement method, previously, urea resin-based ground improvement material was used, but in recent years when the safety requirements for underground digging work have become strict,
The ground improvement material used has also changed, so that cement and water glass (sodium silicate) have been exclusively used so that a firmer ground can be obtained. That is, recently, a ground improvement material called column jet, which mainly contains cement and is added with water glass to enhance the compressive strength of the ground, has come to be generally used. In addition, the ground improvement method using such a ground improvement material, due to the recent diversification and complexity of construction sites,
It has increased dramatically.

[0011]

By the way, in the conventional shield excavator of the non-center shaft supporting system, among the seal gaps formed between the annular seal portion and the annular seal portion receiver, the seal gap at the front end portion of the seal gap is formed. Although the excavated earth and sand were allowed to enter, the cutter seal prevented the invasion of the excavated earth and sand to the area where the swivel bearing and the pinion were provided, and the manufacturing was performed. Completely sealing such a seal gap so that soil and sand also do not enter the front end part is not only difficult due to the mounting structure of the cutter seal, but until now, such a design itself is meaningless in practice. This is because the. That is, in the conventional one, the excavated earth and sand enter the seal gap at the front end portion, but since the excavated earth and sand have a certain degree of fluidity, this does not hinder the rotation of the cutter. However, recently, in a shield machine with a non-center shaft support method, excavation earth and sand that enter the seal gap at the front end portion during the excavation solidify and interfere with the drive of the cutter, or damage the cutter seal. I encountered a new problem that I have never seen before. As a result of investigating the cause, it was found that such a problem occurs in connection with the ground improvement method using the ground improvement material whose main component is cement.

In order to clarify this, a detailed description will be given of a shield construction method in which the ground improvement method using the ground improvement material containing cement and water glass as described above is used in combination. When such a shield construction method is carried out, the ground improvement material is used. After being filled in the ground, it is cured for at least 4 weeks to allow the hardening reaction of the cement to progress and to provide the ground with the necessary guarantee strength. The cement, which has undergone the hardening reaction, has the property that it hardens by repeating the hardening reaction again when it absorbs an appropriate amount of water. In the shield method using the recent ground improvement method together, the excavation work with the shield machine is performed on the improved ground having such characteristics. Then, when such improved ground is excavated by a conventional shield excavator of a non-center shaft supporting system, the earth and sand of the improved ground including cement becomes powdery by the excavation and enters the front end portion of the seal gap. The soil of the improved ground that has entered this seal gap contains a large amount of cement and is in the form of powder that easily reacts with water.
When the groundwater is absorbed properly, it undergoes a curing reaction again and solidifies, and it becomes as if a lump of concrete was clogged in the seal gap. When the ground contains a large amount of natural water, such a phenomenon is unlikely to occur because the amount of water in the water-cement ratio becomes excessive and the hardening reaction of the cement cannot be performed properly, but in general, the ground improvement method In the improved ground where is constructed, the natural water is reduced due to the hardening reaction of cement, so that it tends to occur. Therefore, in the recent shield construction method, the excavated earth and sand that have entered the front end part of the seal gap are solidified to cause a brake action for driving the cutter, or heat is generated due to mutual friction with the annular seal part. , And found that new problems such as impeding the drive of the cutter and damaging the cutter seal occur. It has been found that such a problem has emerged due to the recent qualitative change of the ground improvement material and the increase in the usage frequency thereof as described above, and is a new problem that cannot occur before.

The present invention intends to solve these problems found in the prior art on the basis of such new knowledge. In a shield excavator of a non-center shaft supporting system, a ground improvement area is dug. Also provides a shield machine and its sealing method that prevent excavated soil in the ground improvement area from solidifying in the seal gap in front of the cutter seal and hindering the cutter drive or damaging the cutter seal. The purpose is to do.

[0014]

The object of the present invention is to provide a "shield body, a cutter head provided in front of the shield body, a cutter driving device for driving the cutter head, and a cutter head at the front end. A cutter support member that supports a portion other than the central portion of the cutter and that connects the rear end portion of the cutter drive device to the cutter head, and the cutter support member is a cutter support member main body and an annular seal portion behind the cutter support member. The shield body has an annular seal portion receiver that forms an annular space in which the annular seal portion is mounted. The shield body is composed of the annular seal portion and the annular seal portion receiver, and seals a seal gap therebetween. In a shield machine equipped with a cutter seal device provided with a plurality of cutter seals, a seal between adjacent cutter seals in the cutter seal device is provided. In addition to the lubrication grease supply means for supplying the lubrication grease to the gap, the hard grease supply means for supplying the grease harder than the lubrication grease to the seal gap in the position in front of the cutter seal is provided. " A shield excavator as described in claim 1, wherein: "a shield body, a cutter head provided in front of this shield body, a cutter drive device for driving the cutter head, and a front end portion; With a cutter supporting member that supports a portion other than the central portion of the cutter head and that connects the rear end portion to the cutter driving device and transmits the power thereof to the cutter head, the cutter supporting member including the cutter supporting portion main body and the rear portion thereof. An annular seal part, and the shield body has an annular seal part receiver that forms an annular space for mounting the annular seal part. In a shield machine equipped with a cutter seal device including a plurality of cutter seals configured to seal a seal gap between the seal seal part and the annular seal part receiver, adjacent cutter seals in the cutter seal device are provided. The grease for lubrication is supplied to the seal gap between them, and the grease harder than the grease for lubrication is supplied to the seal gap in front of the cutter seal. " This is achieved by the shield machine sealing method as described in.

[0015]

Since the shield machine according to claim 1 of the present invention is provided with such a configuration, before or after starting the vehicle, if necessary, a hard grease supplying means is used to remove the lubricating grease from the lubricating grease. Supplies hard grease to the seal gap in front of the cutter seal. Thus, even if the excavation work is advanced by the shield excavator, and even if the improved ground that has undergone the ground improvement method is excavated in the process, hard grease is supplied to the seal gap in the position forward of the cutter seal, and this hard Since the grease is hard to escape from the seal gap and is not easily replaced with the excavated soil, it is possible to prevent the powder of excavated soil containing cement generated by the excavation of the improved ground from trying to enter the seal gap from the front end of the shield body. it can. Therefore, even when excavating the improved ground, there is a problem that powder of excavated sand containing cement is solidified in the seal gap and obstructs the drive of the cutter, as seen in the conventional shield excavator. There is no. Further, since this hard grease also has the inherent property of the grease that it does not harden, it does not adversely affect the drive of the cutter. In addition to providing such a new effect, the lubricating grease can be supplied to the seal gap between the adjacent cutter seals by the lubricating grease supply means as before, so that the sliding portion of the cutter seal is worn and the sliding thereof is prevented. Naturally, the same action as that of the conventional shield machine, which can prevent the intrusion of earth and sand from the moving part, can be achieved.

The method of sealing a shield machine according to claim 2 of the present invention corresponds to the method of using the shield machine of claim 1, and relates to the shield machine of claim 1. Since the above-described action is nothing but the action exhibited in the process of using this shield machine, the sealing method of the shield machine according to claim 2 of the present invention naturally has the same action as the above-mentioned action. Can play.

[0017]

EXAMPLE An example of the present invention will be described with reference to FIGS. FIG. 1 is an enlarged vertical cross-sectional view of a cutter seal device relating to a peripheral support type shield machine according to a first embodiment of the present invention, and FIG. 2 is an enlarged vertical cross-sectional view of essential parts of the cutter seal device of FIG. 2 is an enlarged vertical cross-sectional view of a main part of the cutter seal device of FIG. 1, which is cut in a phase in the circumferential direction different from that of FIG. 2, and FIG. 4 is a view showing a usage mode of the cutter seal device of FIG. 2 is a partially enlarged sectional view of a portion similar to that of FIG. 5, and FIG.
Is a view cut by changing the phase in the circumferential direction, FIG. 6 is an enlarged vertical cross-sectional view of a main part of a cutter seal device relating to a peripheral support type shield machine of a second embodiment of the present invention, and FIG. 6 is a partial enlarged cross-sectional view of a portion similar to FIG. 6 showing a usage state of the cutter seal device of FIG. 6, FIG. 8 is an enlarged main part of the cutter seal device relating to the peripheral support type shield machine of the third embodiment of the present invention. FIG. 9 is a vertical sectional view, FIG. 9 is a partially enlarged sectional view of a portion similar to FIG. 8 showing a usage mode of the cutter sealing device of FIG. 8, and FIG. 10 is a peripheral support type shield excavator of a fourth embodiment of the present invention. FIG. 11 is an enlarged vertical sectional view of an essential part of the cutter sealing device, FIG. 11 is a partially enlarged sectional view of FIG. 10 showing a usage mode of the cutter sealing device of FIG. 10, and FIG. 12 is an intermediate beam supporting type of an embodiment of the present invention. Cutter seal for shield machine It is an enlarged longitudinal sectional view of the location. In FIGS. 1 to 12, the parts denoted by the same reference numerals as those in FIGS. 13 to 19 represent the same parts as those in these drawings, and therefore will not be described in detail to avoid duplication of description.

The shield machine of the first, second, third, and fourth embodiments of the present invention is the shield main body 1 and the shield main body as in the conventional shield machine. Cutter head 3 provided in front of 1, hydraulic motor 11a, pinion 11b, and slewing bearing 11c
And a cutter driving device 1 for driving the cutter head 3.
1 and a cutter support member that supports a portion other than the central portion of the cutter head 3 at the front end portion and connects the rear end portion to the cutter driving device 11 to transmit the power thereof to the cutter head 3, the cutter support member The shield main body 1 has an annular seal portion receiver 7 which is composed of a cutter support portion main body and an annular seal portion 6 behind the cutter support portion, and which forms an annular space in which the annular seal portion 6 is mounted. The cutter seal device 8 is provided with a plurality of cutter seals 9a and 9b for sealing the seal gaps 16 and 17 between them, and the basic structure is the same as the conventional one. There is no difference from the shield machine.

First, the characteristic structure of the shield machine of the first embodiment will be described with reference to FIGS. 1 to 5. The cutter seal device 8 shown in these figures relates to a peripheral support type shield machine. It is a thing. In these drawings, 30 is a hard grease inlet for supplying hard grease harder than lubricating grease to the outer seal gap 16, and in the present embodiment, the seal outer peripheral receiving portion 7a of the annular seal receiving portion 7 is provided. The through hole penetrating the wall is formed so as to communicate with the seal gap 16c at the front end portion in front of the cutter seal 9a. Reference numeral 31 is a similar hard grease injection port formed on the seal portion inner circumference receiving portion 7b side of the annular seal portion receiving portion 7, and the front end in front of the cutter seal 9b is formed by a through hole penetrating the wall of the seal portion inner circumference receiving portion 7b. It is formed so as to communicate with the seal gap 17c at the part.

When the hard grease injection ports 30 and 31 are formed in the seal outer peripheral receiving portion 7a and the seal inner peripheral receiving portion 7b, respectively, in FIG. 1, the lubricating grease communicating port 22a on the outer sealing side and the inner seal side 22a are formed. Although it is illustrated as being formed at the same circumferential phase position as the lubricating grease communication port 23, such hard grease injection ports 30 and 31 may be formed at other circumferential phase positions or may be added. be able to. This is the outer peripheral receiving portion 7a of the seal portion.
The hard grease injection port 30 formed in FIG. 3 will be described as an example. Instead of forming the hard grease injection port 30 at the same circumferential phase position as the lubricating grease communication port 22a as shown in FIG. 3 and the circumferential direction phase position shown in FIG. 5, and further, FIGS.
Also, they can be formed simultaneously at the circumferential phase positions shown in FIG. FIG. 3 shows the lubricating grease communication port 22.
The case where the hard grease injection port 30 is formed at the circumferential phase position where neither a nor 22b is formed is shown in FIG. 5, and FIG. 5 shows the lubricating grease communication port 22b on the outer seal side.
The case where the hard grease injection port 30 is formed at the same circumferential phase position as in FIG.

The hard grease is directly injected into the seal gaps 16c and 17c from the inlet openings 30a and 31a of the hard grease injection ports 30 and 31 in the factory or in the vertical shaft before starting. As the lubricating grease to be supplied to the seal gaps 16a, 16b, 17a, greases having a consistency of 0 or 1 are usually used, but the hard grease injected into the seal gaps 16c, 17c is a grease having a consistency of 3 or more. Or fiber grease is used. These hard greases are not only hard seal materials, but also do not harden after being injected into the seal gaps 16c and 17c.
It also has the characteristic of being harder to escape than 17c. That is, such a hard grease has a characteristic that the grease does not harden, and has a characteristic that it is harder than the lubricating grease and is hard to escape. After injecting the hard grease into the seal gaps 16c and 17c through the hard grease injecting ports 30 and 31, naturally, it is necessary to close these injecting ports 30 and 31 so that the hard grease does not leak to the outside. Is. Therefore, in this embodiment, as shown in FIG. 4 regarding the hard grease inlet 30, the inlet-side openings 30a and 31a of the inlets 30 and 31 are closed by the plug 32 with the tap lock cut. I have to.

Since the shield machine of the present embodiment has such a structure, the hard grease inlets 30 and 31 are provided with the openings 30 on the inlet side in the factory or in the vertical shaft before starting.
Hard grease from a, 31a Seal gap at front end 1
6c, 17c are pre-injected into each of the inlet side openings 30
Start with the plugs 32, 31a, 31a closed. After the start, the ground improvement area 47 immediately after the start as shown in FIG. 21 and the ground improvement area 4 on the way as shown in FIG. 22.
When the ground of No. 7 is excavated, the powder of excavated earth and sand containing cement generated by the excavation tries to invade the seal gaps 16c, 17c from the front end of the shield body 1, but hard grease is left in the seal gaps 16c, 17c. Pre-filled and this hard grease is
Since it is difficult to escape from the c and 17c and is not easily replaced with the excavated earth and sand, it is possible to prevent the powder of the excavated earth and sand containing the cement from invading. Moreover, since this hard grease also has an inherent characteristic of the grease that it does not harden, it does not adversely affect the drive of the cutter 2. Therefore, according to the present embodiment, even when the ground improvement area 47 is dug, the cement powder is solidified in the seal gaps 16b and 16c like the conventional shield excavator, and the cutter 2
The driving of the cutter can be smoothly performed without damaging the cutter seals 9a and 9b by inhibiting the driving of the cutter or causing heat generation due to mutual friction with the annular seal portion 6 and the like.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. The shield machine according to the second embodiment will be described as follows.
Similar to the first embodiment, the hard grease injection port 30 is formed so as to communicate with the seal gap 16c at the tip end portion through the through hole penetrating the wall of the seal outer peripheral receiving portion 7a. A hard grease supply passage 33 is formed in the front-rear direction inside the outer peripheral receiving portion 7a. The hard grease supply passage 33 communicates with the hard grease injection port 30 and supplies the hard grease from the injection port 30 to the seal gap 16c at the tip portion. Although not shown, a hard grease supply pump is installed in this way so that the hard grease can be supplied to the seal gap 16c through the hard grease supply passage 33. Such a hard grease supply passage 33 can naturally be formed in the seal inner peripheral receiving portion 7b. As described above, the hard grease is used before the start of the shield machine, in the factory or in the shaft, from the hard grease injection ports 30 and 31 to the seal gap 16
Although it can be directly injected into the c and 17c, after the start, the hard grease injection ports 30 and 31 are located on the face of the face, and thus it is impossible to inject by such a method. On the other hand, even when hard grease is preliminarily injected in the factory or in the shaft before the shield machine is started, the hard grease may be dispersed to the outside when the shield machine is driven for a long distance. In response to such a situation, the hard grease supply passage 33 is provided so as to be able to supply the seal gaps 16c and 17c at any time even after the shield machine is started. When the hard grease is supplied to the seal gaps 16c and 17c through the hard grease supply passage 33, it is supplied by a pump. In that case, the inlet side opening 3 of the hard grease inlets 30 and 31
Since 0a and 31a are previously covered with the plug 32 as described above, the hard grease does not leak outside. As described above, according to the present embodiment, as compared with the first embodiment, there is an advantage that the hard grease can be supplied as needed after the start of the shield machine or appropriately replenished.

Next, referring to FIGS. 8 and 9, the third embodiment will be described. In the shield machine of the third embodiment, as in the case of the first embodiment, the seal outer peripheral receiving portion 7a is provided in the front-rear direction. The lubricating grease supply passage 20b formed in the above, and the hard grease injection port 30 formed so as to communicate with the seal gap 16c at the front end portion by the through hole penetrating the wall of the seal portion outer peripheral receiving portion 7a. A hard grease supply connection passage 34 communicating with both the lubricating grease supply passage 20b and the hard grease inlet 30 is formed in the front-rear direction inside the seal portion outer peripheral receiving portion 7a. Also, unlike the first embodiment, instead of the lubricating grease communication port 22b of FIG. 5, the lubricating grease injection port 35 is formed by a through hole penetrating the wall surface of the seal portion outer peripheral receiving portion 7b to form the seal gap 16b.
It is formed so as to communicate with. In this embodiment, the lubricating grease supply passage 20b is based on such a configuration.
Can also be used as the hard grease supply passage 33 as in the second embodiment. Therefore, in this embodiment, as shown in FIG. 9, in addition to the plug 32 described above, an adapter 36 is attached as an attachment. This adapter 36 has two ends 36 as shown in FIG.
a and 36b have a large diameter and an intermediate portion 36c has a small diameter, and are formed in a drum shape, and both end portions 36a and 36 when inserted into the lubricating grease inlet 35 or the hard grease inlet 30.
b is the inlet-side opening 35a of the lubricating grease injection port 35,
The outlet side opening 35b, the inlet side opening 30a of the hard grease inlet 30, and the outlet side opening 30b are fitted to seal these openings, and the intermediate portion 36c supplies the lubricating grease supply passage 20b and the hard grease supply. A communication gap is formed at a position corresponding to the connection path 34.

In the third embodiment, since the structure as described above is adopted, the lubricating grease supply passage 20b is also used as a part of the hard grease supply passage, and the hard grease is provided in the seal gap 16c at the front end portion. If you want to supply,
As shown in, the plug 32 is fitted into the inlet side opening 30a of the hard grease inlet 30 to close the opening 30a, and the adapter 36 is inserted into the lubricating grease inlet 35. After that, when a hard grease supply pump (not shown) is driven to pump the hard grease from the lubricating grease supply passage 20b, the hard grease is transferred to the adapter 36.
Through the communication gap formed at the intermediate portion 36c of the hard grease supply port 34 and the hard grease supply connection passage 34.
From the outlet side opening 30b of the seal gap 16c at the front end portion
Is supplied to. In that case, since the inlet-side opening 35a and the outlet-side opening 35b of the lubricating grease injection port 35 are sealed by the adapter 36, they flow out to the outside or are supplied to the seal gap 16b between the outer seals 9a. There is nothing to do. When the lubricating grease is to be supplied from the lubricating grease injection port 35 to the seal gap 16b, this time, the plug 32 is fitted into the inlet side opening portion 35a of the lubricating grease injection port 35 and the opening is formed. The adapter 35 is inserted into the hard grease inlet 30 while closing the portion 35a. After that, when the lubricating grease supply pump is driven to pump the hard grease from the lubricating grease supply passage 20b, both openings 30a and 30b of the hard grease injection port 30 of the lubricating grease are blocked by the adapter 36. Therefore, it is exclusively supplied from the outlet side opening 35b of the lubricating grease injection port 35 to the seal gap 16b between the outer seals 9a. The shield machine of the present embodiment is expected to have the same effects as those of the second embodiment, and the lubricating grease supply passage 20b is also used as a part of the hard grease supply passage. The processing steps of the product can be simplified compared to the example.

As is apparent from the above description, the adapter 36 is a means for allowing the lubricating grease supply passage 20b to communicate only with the hard grease supply connection passage. Other components may be used as long as they satisfy the above requirements. In this embodiment, when the lubricating grease is to be supplied from the lubricating grease inlet 35 to the seal gap 16b, the adapter 36 is inserted into the hard grease inlet 30 to close it. Is only to block the hard grease injection port 30 after the hard grease is injected through the hard grease injection port 30.
This may be closed by some means such as attaching a dedicated means for closing the above as an attachment. Further, it is obvious that such a closing means and the plug 32 should be naturally provided in the design in the process of carrying out the present invention. Therefore, the configuration relating to them is not directly related to the essence of the present invention. It is a matter of design.

Next, referring to FIGS. 10 and 11, the fourth embodiment will be described. The shield machine according to the fourth embodiment will be explained as follows.
Similar to the embodiment, the lubricating grease supply passage 20a formed in the front and rear direction in the seal portion outer peripheral receiving portion 7a and the through hole penetrating the wall of the seal portion outer peripheral receiving portion 7a communicate with the seal gap 16c at the front end portion. And a hard grease injection port 30 formed to Also, as in the third embodiment,
A hard grease supply connection 34 that communicates with both the lubricating grease supply passage 20a and the hard grease inlet 30.
Is formed in the seal portion outer peripheral receiving portion 7a in the front-rear direction, and instead of the lubricating grease communicating port 22a of FIG. 2, a lubricating grease injection port 35 is formed as a through hole penetrating the wall surface of the seal outer peripheral receiving portion 7a. Is formed so as to communicate with the seal gap 16a. That is, the configuration of the flow paths for supplying the soft grease and the hard grease is different from that of the third embodiment in that the lubricating grease injection port 35 and the seal gap 1 are provided.
Is it formed so as to communicate with 6a? Seal gap 16b
There is only a difference in terms of whether they are formed so as to communicate with each other, and basically there is no difference. In the fourth embodiment, in addition to the configuration of the third embodiment, in addition to the adapter 36 attached in the third embodiment as an attachment,
An adapter 37 with a check valve is additionally provided, which is different from that of the third embodiment in this respect. As shown in FIG. 11, the check valve adapter 37 has two end portions 37.
a and 37b have a large diameter and an intermediate portion 37c has a small diameter, and are formed in a drum shape, and both ends 37a and 37b are used by being fitted into the openings 30a and 30b of the hard grease inlet 30. It is designed to close 30 and is similar to the adapter 36 in terms of such usage. A flow path is formed from the intermediate portion 37c to the end portion 37b, and a check valve is provided in this flow path, which is different from the adapter 36 in that such a structure is added. With the check valve adapter 37 configured as described above, when fitted to the hard grease inlet 30, the hard grease from the hard grease supply connection passage 34 to the outlet side opening 30b of the hard grease inlet 30 is hard grease. Of the hard grease supply connection passage 34 from the outlet opening 30b of the hard grease supply connection passage 34, and prevents the fluid from flowing into the hard grease supply connection passage 34 from the outlet opening 30b. It can serve to prevent the outflow of hard grease to the.

Since the fourth embodiment employs the above-mentioned structure, before the shield machine is started, in the state shown in FIG. 10, the inlet of the hard grease inlet 30 in the factory or in the vertical shaft. Side opening 30a and grease inlet 3 for lubrication
Hard grease or lubricating grease can be injected and filled into the seal gap 16c or the seal gap 16a from the inlet-side opening 35a of No. 5. However, when the grease for lubrication is injected and filled in the seal gap 16a, if the hard grease injection port 30 is closed by the adapter 36 and the inlet side opening 35a of the lubrication grease injection port 35 is closed by the plug 32, The grease can also be pumped to the seal gap 16a through the lubricating grease supply passage 20a. When the grease filling is completed in this way, as shown in FIG. 11, the hard grease inlet 30 is connected to the adapter 37 with a check valve.
The lubricating grease injection port 35 is closed with the adapter 36. When it is necessary to replenish the hard grease after starting the shield machine in such a state, a hard grease supply pump (not shown) is driven to pump the hard grease from the lubricating grease supply passage 20a. Then, the hard grease is guided from the intermediate portion 37c side to the end portion 37b side by the check valve adapter 37 via the communication gap formed in the intermediate portion of the adapter 36 and the hard grease supply connection path 34, Hard grease inlet 30
It is possible to supply and fill the seal gap 16c from the outlet side opening 30b. In that case, the hard grease is used as both the inlet side and the outlet side 35 of the lubricating grease inlet 35.
Since a and 35b are sealed by the adapter 36, they are supplied only from the outlet side opening 30b of the hard grease inlet 30 to the seal gap 16c at the front end portion. Further, when the hard grease is supplied and filled in the seal gap 16a in this manner, as described above, it is necessary to prevent the powder of the excavated earth and sand containing cement from entering the seal gap 16c at the front end portion and solidifying. However, muddy water and some excavated soil may be mixed in. In this embodiment, the hard grease inlet 30
In particular, since the adapter 37 with a check valve is used to close the valve, it is possible to replenish the hard grease from the inside of the machine, but muddy water and excavated soil mixed in the seal gap 16c from the hard grease injection port 30. It functions to prevent the hard grease supply connection path 34 from entering and through the connection path 34 to get into various places, thereby clogging these flow paths and contaminating grease. The shield machine of this embodiment can be expected to have the same effects as those of the third embodiment, and in this way, even after the shield machine has started, hard grease can be appropriately replenished from inside the machine as necessary, and Even if muddy water or excavated earth and sand is mixed in the seal gap 16c at the front end portion, it is possible to obtain the effect of preventing the muddy water and excavated sand from entering the hard grease supply connection path 34 and the like.

Although various embodiments of the present invention have been described above by taking the peripheral support type shield machine as an example, the peripheral beam support type shield machine shown in FIG. 16 and the intermediate machine shown in FIGS. Also in the beam support type shield machine, since the structure itself of the cutter seal device 8 is basically the same as that of the peripheral support type shield machine,
The above-described various embodiments relating to the peripheral support type shield machine are naturally applicable to the outer beam support type shield machine and the intermediate beam support type shield machine. As an example thereof, FIG. 12 shows an example in which the first embodiment of the present invention shown in FIG. 1 is applied to an intermediate beam support type shield machine. As is clear from comparison of FIG. 12 with FIG. 1, the intermediate beam support type shield machine has a slight difference in the cutter head support system from the peripheral support type shield machine, and the present invention is not limited to this. In other respects, when implemented, there is basically no difference from the peripheral support type shield machine.

[0030]

As is apparent from the above description, the shield machine according to the present invention has a "shield body, a cutter head provided in front of the shield body, a cutter driving device for driving the cutter head, and a front end. A cutter supporting member that supports a portion other than the central portion of the cutter head by a portion and connects the rear end portion to a cutter driving device to transmit the power thereof to the cutter head, the cutter supporting member being the cutter supporting portion main body and the rear thereof. And a shield main body having an annular seal part receiver that forms an annular space in which the annular seal part is mounted, and the seal body is composed of the annular seal part and the annular seal part receiver. In a shield machine equipped with a cutter seal device provided with a plurality of cutter seals for sealing gaps, adjacent cutters in the cutter seal device are provided. In addition to lubricating grease supply means for supplying lubricating grease to the seal gap between the seals, hard grease supplying means for supplying grease harder than lubricating grease to the seal gap in front of the cutter seal is provided. The sealing method of the shield machine according to the present invention, in the same shield machine, supplies grease for lubrication to the seal gap between the adjacent cutter seals in the cutter seal device, and applies grease harder than the grease for lubrication to the cutter. Since it is supplied to the seal gap located in front of the seal, even if the ground excavation area is excavated in the shield excavator of the non-center shaft support type, the excavated soil in the soil improvement area is the same as the conventional shield excavator. The cutter seal is solidified in the seal gap in front of the cutter seal, obstructing the cutter drive, It is not such thing as or damage Lumpur.

[Brief description of drawings]

FIG. 1 is an enlarged vertical sectional view of a cutter seal device relating to a peripheral support type shield machine according to a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a main part of the cutter seal device of FIG.

FIG. 3 is an enlarged vertical cross-sectional view of a main part of the cutter seal device of FIG. 1, which is a view cut with a phase in the circumferential direction changed.

FIG. 4 is a view showing a usage mode of the cutter seal device of FIG.
It is a partially expanded sectional view of a part similar to FIG.

5 is an enlarged vertical cross-sectional view of a main part of the cutter seal device of FIG. 1, which is a view in which the phase in the circumferential direction is changed from that in FIGS.

FIG. 6 is an enlarged vertical cross-sectional view of a main part of a cutter seal device for a peripheral support type shield machine according to a second embodiment of the present invention.

FIG. 7 is a view showing a usage mode of the cutter seal device of FIG. 6;
It is a partially expanded sectional view of a part similar to FIG.

FIG. 8 is an enlarged vertical cross-sectional view of a main part of a cutter seal device for a peripheral support type shield machine according to a third embodiment of the present invention.

9 is a view showing a usage mode of the cutter seal device of FIG. 8;
It is a partially expanded sectional view of a part similar to FIG.

FIG. 10 is an enlarged vertical cross-sectional view of a main part of a cutter seal device relating to a peripheral support type shield machine according to a fourth embodiment of the present invention.

11 is a partially enlarged cross-sectional view of a portion similar to FIG. 10 showing a usage state of the cutter seal device of FIG.

FIG. 12 is an enlarged vertical cross-sectional view of a cutter seal device for an intermediate beam support type shield machine according to an embodiment of the present invention.

13A and 13B are views showing an example of a peripheral support type shield machine conventionally used, in which FIG. 13A is a front view and FIG. 13B is a vertical sectional view.

14 is an enlarged vertical cross-sectional view of a cutter seal device for the shield machine of FIG.

FIG. 15 is an enlarged vertical cross-sectional view of the cutter sealing device for the shield machine of FIG. 13, which is cut in a state in which the phase in the circumferential direction is changed.

FIG. 16 is a view showing an example of a shield beam excavator of a peripheral beam supporting type which has been conventionally used, in which (a) is a front view,
(B) is a longitudinal sectional view.

FIG. 17 is a view showing an example of a conventionally used intermediate beam supporting type shield machine, (a) is a front view,
(B) is a longitudinal sectional view.

18 is an enlarged vertical cross-sectional view of a cutter seal device for the shield machine of FIG.

19 is an enlarged vertical cross-sectional view of the cutter sealing device relating to the shield machine of FIG. 17, and is a diagram cut with a phase in the circumferential direction changed.

FIG. 20 is a vertical cross-sectional view of a construction site for explaining the excavation method using the shield excavator, and is a diagram showing a starting preparation state.

FIG. 21 is a vertical sectional view of a construction site similar to FIG. 20, showing a state immediately after the shield machine is started.

22 is a vertical cross-sectional view of a construction site similar to FIG. 20, showing a state where the shield machine is in the process of being excavated.

[Explanation of symbols]

 1 Shield main body 2 Cutter 3 Cutter head 5 Cutter support cylinder 5a Cutter outer peripheral support beam 5b Cutter intermediate support beam 6 Annular seal part 7 Annular seal part receiving 7a Seal part outer peripheral receiving part 7b Sealing part inner peripheral receiving part 7c Seal Part receiving and shielding part 8 Cutter seal device 9a Outer cutter seal 9b Inner cutter seal 10 Partition wall 11 Cutter drive device 11a Cutter drive hydraulic motor 11b Pinion 11c Swivel ring 16 Outer seal gap 17 Inner seal gap 18a, 18b Outer seal greasing pipe 19 Inner seal greasing pipe 20a, 20b Outer seal side lubricating grease supply path 21 Inner seal side lubricating grease supply path 22a, 22b Outer seal side lubricating grease communication port 23 Inner seal side lubricating grease communication port 30, 31 Hard grease inlet 32 Plug 3 3 Hard grease supply path 34 Hard grease supply connection path 35 Lubrication grease inlet 36 Adapter 37 Check valve adapter 40 Ground 47 47 Ground improvement area

Claims (10)

[Claims] 1. A shield main body, a cutter head provided in front of the shield main body, a cutter driving device for driving the cutter head, a front end portion for supporting a portion other than a central portion of the cutter head, and a rear end portion for the cutter. A cutter support member that is connected to a drive unit and transmits its power to the cutter head, the cutter support member including a cutter support part main body and an annular seal part behind the cutter support part, and the shield main body mounts the annular seal part A cutter seal device is provided, which has an annular seal portion receiver that forms an annular space, and is composed of the annular seal portion and the annular seal portion receiver, and is provided with a plurality of cutter seals that seal a sealing gap between them. In the shield machine, the lubrication grease that supplies the lubrication grease to the seal gap between the adjacent cutter seals in the cutter seal device. In addition to the grease supply means, a shield machine having a hard grease supply means for supplying a grease harder than the lubricating grease to the seal gap located in front of the cutter seal. 2. The shield machine according to claim 1, wherein the cutter support body is a cylindrical body that supports an outer peripheral portion of the cutter head. 3. The shield machine according to claim 1, wherein the cutter support body is a plurality of beams supporting the outer peripheral portion of the cutter head. 4. The shield machine according to claim 1, wherein the cutter support body is a plurality of beams that support the middle of the center and the outer periphery of the cutter head. 5. A lubrication grease supply means is formed with a lubrication grease supply passage in the front-rear direction in an annular seal portion receiver so as to communicate with a seal gap between adjacent cutter seals in a cutter seal device. 3. The grease supply means, wherein a hard grease inlet is formed so as to communicate with a seal gap in front of the cutter seal by a through hole penetrating the wall of the annular seal portion receiver. The shield machine according to claim 3 or 4. 6. The hard grease supply means includes a hard grease supply passage formed in the front-rear direction in the annular seal portion receiver, and a hard grease inlet communicating with the hard grease supply passage is provided in the annular seal portion receiver wall. The shield machine according to claim 1, claim 2, claim 3, or claim 4, wherein the through hole is formed so as to communicate with a seal gap in front of the cutter seal. 7. A lubrication grease supply means is formed with a lubrication grease supply passage in the front-rear direction in an annular seal portion receiver, and a lubrication grease injection port communicating with the lubrication grease supply passage is provided as an annular seal. A hard grease supply connection path that is formed between adjacent cutter seals by a through hole that penetrates the wall surface of the part receiver and that communicates with the grease supply path for lubrication is provided in the annular seal part receiver in the front-back direction. The hard grease inlet, which is connected to the hard grease supply connection path, is formed in front of the cutter seal by a through hole that penetrates between the inner and outer surfaces of the annular seal receiver, and the grease supply path for lubrication is hard grease. A means capable of communicating only with the supply connection path is attached, and the means of claim 1, claim 2, claim 3 or claim 4 is provided. Shield machine. 8. The hard grease inlet is used by being fitted, and at the time of fitting, the hard grease is allowed to flow from the hard grease supply connection passage to the outlet side opening of the hard grease inlet, and the outlet thereof is provided. A means for preventing the inflow of fluid from the side opening to the hard grease supply connection passage and preventing the outflow of hard grease from the hard grease supply connection passage to the inlet side opening of the hard grease inlet has been added. The shield machine according to claim 7, which is characterized in that. 9. A shield main body, a cutter head provided in front of the shield main body, a cutter driving device for driving the cutter head, a front end portion of the cutter head other than a central portion thereof, and a rear end portion of the cutter head. A cutter support member that is connected to a drive unit and transmits its power to the cutter head, the cutter support member including a cutter support part main body and an annular seal part behind the cutter support part, and the shield main body mounts the annular seal part A cutter seal device is provided, which has an annular seal portion receiver that forms an annular space, and is composed of the annular seal portion and the annular seal portion receiver, and is provided with a plurality of cutter seals that seal a sealing gap between them. In addition to supplying lubrication grease to the seal gap between adjacent cutter seals in the cutter seal device, A sealing method for a shield machine, characterized in that grease harder than grease is supplied to a seal gap in front of the cutter seal. 10. The sealing method for a shield machine according to claim 9, wherein the grease harder than the lubricating grease is grease having a consistency of 3 or more or fiber grease.