Fluidizing liquid supply structure for shield tunneling machines

Abstract

To provide a supply part structure of a fluidization liquid material in a mud pressure-type shield machine capable of preventing the entry of cut sediment into an injection part by a simple constitution, when cutting soil while injecting the fluidization liquid material.SOLUTION: A supply part structure of a fluidization liquid material is constituted by including a discharge cylindrical body 11 having a liquid material discharge opening 12 on a side peripheral surface 11a, a guide wall part 13 annularly provided on the outer side of the discharge cylindrical body 11, and an elastic sleeve member 14 fitted by covering the liquid material discharge opening 12. The elastic sleeve member 14 is positioned on the side peripheral surface 11a of the discharge cylindrical body 11 by screwing a nut-like member 15 to tip end parts of the discharge cylindrical body 11. The nut-like member 15 has an annular skirt part 15a extended to the excavating direction X rear side from the outer peripheral edge part. The annular skirt part 15a is arranged to cover the tip end part of the excavating direction X front side of the elastic sleeve member 14 from outside.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a supply section structure for fluidized liquid material in a shield tunneling machine, and in particular to a supply section structure for supplying fluidized liquid material that generates plastically fluidized mud to a cutter chamber in a mud pressure type shield tunneling machine. [Background technology]

[0002] As a shield tunneling machine, a mud pressure type shield tunneling machine is a machine that excavates the ground at the face while stabilizing it by cutting the ground at the face with a rotating cutter, and then mixing the soil and sand that is taken into the cutter chamber with a liquid material that preferably contains a plastic fluidizing agent such as a mud making agent, to generate plastically fluidized mud.The mud that is generated when the generated mud is filled into the cutter chamber is then used to generate mud pressure.

[0003] Furthermore, in such a mud pressure shield machine, when the ground is excavated by the rotating cutter, which is driven to rotate by the drive unit, a liquid material containing a plastic fluidizer is supplied from a supply unit attached to the rotating cutter toward the ground at the working face, causing the excavated earth and sand to be stirred together with the liquid material containing the plastic fluidizer in the chamber (see, for example, Patent Document 1). As the ground at the working face is excavated, the mud that has been stirred together with the liquid material containing the plastic fluidizer and plastically fluidized is discharged to the rear of the shield machine via a screw conveyor, one end of which opens into the partition wall that divides the cutter chamber, while maintaining a state in which mud pressure is generated by the mud filled in the cutter chamber. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-234494 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, a proposed supply section structure for supplying fluidizing liquid containing a plastic fluidizer from a rotary cutter to the ground at the cutting face, such as that shown in Figure 6, has been designed to prevent the fluidizing liquid discharge port from becoming clogged with earth and sand during cutting by the rotary cutter. The proposed fluidizing liquid supply section structure 50 shown in Figure 6 includes a top-mounted cylindrical discharge cylinder 52, which is connected to a fluidizing liquid supply pipe 51 and has multiple fluid discharge openings 53 on its circumferential surface and a closed tip 54. An elastic sleeve member 55 is attached to the circumferential surface of the discharge cylinder 52, covering the fluid discharge openings 53. Covering the fluid discharge openings 53 with the elastic sleeve member 55 prevents clogging with earth and sand during cutting. The elastic sleeve member 55 is positioned to prevent misalignment by a nut-shaped member 56 threaded onto the tip of the discharge cylinder 52.

[0006] In the structure 50 of the fluidizing liquid material supply section proposed in Figure 6, the fluidizing liquid material pressurized through the supply pipe 51 is discharged from the liquid material discharge opening 53, lifting the elastic sleeve member 55 due to the pressure, and the discharged fluidizing liquid material is forcefully sprayed out from both ends of the elastic sleeve member 55 through the gap between the lifted elastic sleeve member 55 and the side surface of the discharge cylinder 52.In particular, the fluidizing liquid material sprayed out from the rear end of the elastic sleeve member 55 in the excavation direction X collides with the tapered wall surface portion 57a ​​of the guide wall portion 57 provided in a ring shape on the outside of the discharge cylinder 52, and is then guided by the guide wall portion 57 and sprayed out while diffusing toward the front side in the opposite excavation direction X.

[0007] However, in the structure 50 of the fluidizing liquid supply section proposed in Figure 6, when the shield tunneling machine (see Figure 1) is advanced in the tunneling direction X, the fluidizing liquid is sprayed, and the ground at the face is cut with the rotating cutter, there is a risk that the earth and sand cut by the pressure during tunneling will flow back into the gap at the end of the elastic sleeve member 55 on the front side in the tunneling direction X, which has been turned up by the pressure of the fluidizing liquid, and will cause the gap to become blocked.

[0008] If cut earth and sand get into the gap at the end of the turned-up elastic sleeve member 55 on the front side in the excavation direction X, it is possible to take measures to remove the cut earth and sand using hydraulic pressure, but attempting to remove it using hydraulic pressure would result in a considerable amount of oil flowing into the ground, increasing the burden on the environment. For this reason, there is a need for a means of effectively preventing cut earth and sand from getting into the gap at the end of the elastic sleeve member on the front side in the excavation direction when a mud pressure shield machine is advanced in the excavation direction X, spraying fluidizing liquid and cutting the ground at the face with the rotary cutter.

[0009] The present invention aims to provide a fluidized liquid material supply structure for a shield tunneling machine that, with a simple configuration, can effectively prevent cut earth and sand from entering the gap at the end of the elastic sleeve member on the forward side in the tunneling direction when the mud pressure type shield tunneling machine is advanced in the tunneling direction, spraying fluidized liquid material and cutting the ground at the face with a rotating cutter. [Means for solving the problem]

[0010] The present invention relates to a shield tunneling machine of a mud pressure type that cuts the ground with a rotary cutter while stabilizing the face with mud filled in a cutter chamber, and a fluidizing liquid material that generates plastically fluidized mud, Towards the ground at the facethe supply section structure for supplying fluidized liquid material in a shield tunneling machine is provided, and is composed of a topped, cylindrical discharge cylinder that communicates with the supply pipe for the fluidized liquid material and that protrudes forward in the excavation direction from the rotating cutter, has a plurality of liquid material discharge openings on its side peripheral surface, and has a closed tip; guide walls that are provided in an annular shape at intervals on the outside of the discharge cylinder; and an elastic sleeve member that covers the plurality of liquid material discharge openings and is attached in a state of tight contact with the side peripheral surface of the discharge cylinder, the elastic sleeve member being positioned on the side peripheral surface of the discharge cylinder by a nut-shaped member that has a female thread ridge formed on its inner peripheral surface being screwed onto a male thread ridge formed on the side peripheral surface of the tip portion of the discharge cylinder, and the nut-shaped member has an annular skirt portion that extends rearward in the excavation direction from the outer periphery, and the annular skirt portion is arranged so as to cover from the outside the tip portion of the positioned elastic sleeve member on the front side in the excavation direction.

[0011] In the structure of the fluidizing liquid supply section in the shield tunneling machine of the present invention, it is preferable that the guide wall section has a tapered wall surface section that widens towards the front in the tunneling direction.

[0012] In the fluidizing liquid material supply structure for a shield tunneling machine of the present invention, the elastic sleeve member is preferably made of natural rubber having a hardness of A55 to A75 according to JIS K 6253.

[0013] Furthermore, in the structure of the fluidizing liquid material supply section of the shield tunneling machine of the present invention, it is preferable that the natural rubber has a thickness of 5 to 10 mm.

[0014] Furthermore, it is preferable that the supply section structure of the fluidized liquid material in the shield tunneling machine of the present invention is such that the annular skirt portion of the nut-shaped member is attached with its inner surface in close contact with the outer surface of the tip portion of the elastic sleeve member on the forward side in the tunneling direction.

[0015] Furthermore, it is preferable that the supply section structure for the fluidized liquid material in the shield tunneling machine of the present invention is such that both end portions are joined to the rotating cutter, and the band-shaped buffer wall member extends radially from the discharge cylinder body, and is attached so as to overlap the discharge cylinder body when viewed from the front in the tunneling direction, with a gap maintained between its inner surface and the tip of the discharge cylinder body. [Effects of the Invention]

[0016] According to the fluidizing liquid supply section structure of the shield tunneling machine of the present invention, when the mud pressure type shield tunneling machine is advanced in the excavation direction while spraying fluidizing liquid and cutting the ground at the face with the rotating cutter, the simple configuration effectively prevents the cut soil and sand from getting into the gap at the end of the elastic sleeve member on the forward side in the excavation direction. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a vertical cross-sectional view of a mud pressure type shield tunneling machine that employs a fluidizing liquid material supply structure according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the mud pressure shield machine of FIG. 1, as seen from the front side in the excavation direction. [Figure 3] FIG. 2 is an enlarged cross-sectional view of part A in FIG. 1, illustrating the structure of a fluidizing liquid material supply unit according to a preferred embodiment of the present invention. [Figure 4] 1(a) is an enlarged cross-sectional view of a supply structure for a fluidizing liquid material according to a preferred embodiment of the present invention, and FIG. 1(b) is an enlarged cross-sectional view of an elastic sleeve member. [Figure 5] 10(a) and 10(b) are enlarged cross-sectional views illustrating other examples of the structure of the supply portion for the fluidizing liquid material. [Figure 6] FIG. 10 is an enlarged cross-sectional view illustrating the structure of a conventional fluidizing liquid material supply unit. DETAILED DESCRIPTION OF THE INVENTION

[0018] A fluidizing liquid supply structure 10 (see Figures 3 and 4(a)) in a shield tunneling machine according to a preferred embodiment of the present invention is adopted as a fluidizing liquid supply structure in a mud pressure type shield tunneling machine 30 shown in Figure 1, for supplying fluidizing liquid, preferably containing a mud-making agent, toward the ground at the working face 33, with the aim of plastically fluidizing the excavated soil and sand taken into the cutter chamber 31 and filling it into the cutter chamber 31 as mud.

[0019] In other words, the mud pressure shield tunneling machine 30 cuts the ground at the working face 33 with the rotating cutter 32, and mixes the soil and sand taken into the cutter chamber 31 with a liquid material preferably containing a plastic fluidizing agent such as a mud making agent, to generate plastically fluidized mud, and then excavates the ground at the working face 33 while stabilizing it using the mud pressure generated by filling the cutter chamber 31 with the generated mud.

[0020] Furthermore, the mud pressure type shield tunneling machine 30 shown in Figure 1 has a structure similar to that of known mud pressure type shield tunneling machines, and cuts the ground at the face 33 with a rotating cutter 32 rotated by a cutter drive unit 34.When stirring the cut earth and sand taken in in a cutter chamber 31 partitioned at the tip by a partition wall 35, a liquid material containing a plastic fluidizing agent is supplied to the ground at the face 33 from two supply parts 32c (see Figure 2) located, for example, on the circular base part 32a of the rotating cutter 32 described below and at the tip of a selected cutting spoke 32b. The mud is mixed and stirred with a liquid material containing a plastic fluidizing agent and plastically fluidized, and as the shield tunneling machine 30 advances while excavating the ground at the face 33, the mud pressure in the cutter chamber 31 keeps the face 33 stable, and the mud is discharged to the rear of the shield tunneling machine 30 via a screw conveyor 36, one end of which opens into the partition wall 35.

[0021] Here, as a structure of the supply section 32c for supplying the fluidizing liquid material containing a plastic fluidizing agent from the rotating cutter 32 toward the ground at the working face 33, a structure has been proposed in which the discharge opening 53 from which the fluidizing liquid material is discharged is covered with an elastic sleeve member 55, as shown in Figure 6 above, to prevent the discharge opening 53 from becoming clogged with the soil and sand being cut by the rotating cutter 32.However, with the structure of the supply section 32c in Figure 6, when the shield tunneling machine 30 is advanced in the excavation direction X and the fluidizing liquid material is sprayed while the rotating cutter 32 cuts the ground at the working face 33, it is possible that the cut soil and sand will enter the gap at the end of the elastic sleeve member 55 on the forward side in the excavation direction X and cause clogging.

[0022] The fluidizing liquid supply section structure 10 in the shield tunneling machine of this embodiment has been designed with the intention of solving the technical problems specific to the structure of the supply section 32c, which supplies fluidizing liquid containing a plastic fluidizing agent from the rotating cutter 32 toward the ground at the face 33.When the mud pressure type shield tunneling machine 30 is advanced in the excavation direction X, fluidizing liquid is sprayed while the rotating cutter 32 cuts the ground at the face 33, and the simple structure effectively prevents the cut earth and sand from getting into the gap at the end of the elastic sleeve member 14 on the forward side in the excavation direction X.

[0023] The fluidized liquid supply structure 10 (see FIG. 4(a)) in the shield machine of this embodiment stabilizes the face 33 with the mud filled in the cutter chamber 31, and in the mud pressure type shield machine 30 (see FIG. 1) that cuts the ground with the rotary cutter 32, the fluidized liquid that generates the plastically fluidized mud is supplied to the shield machine 30. Towards the ground at Face 33The structure of the supply section for supplying the liquid material is as shown in Figures 3 and 4(a), and is composed of a topped cylindrical discharge cylinder 11 that is connected to the fluidized liquid material supply pipe 20 and protrudes forward from the rotating cutter 32 in the excavation direction X, has a plurality of liquid material discharge openings 12 on its side surface 11a, and has a closed tip 11b, a guide wall portion 13 that is arranged in a ring shape at intervals on the outside of the discharge cylinder 11, and an elastic sleeve member 14 that covers the plurality of liquid material discharge openings 12 and is attached in a tight contact state to the side surface 11a of the discharge cylinder 11. The elastic sleeve member 14 is positioned on the side surface 11a of the discharge cylinder 11 by a nut-shaped member 15 having a female thread ridge (not shown) formed on its inner surface being screwed onto a male thread ridge (not shown) formed on the side surface 11a of the tip portion of the discharge cylinder 11, and the nut-shaped member 15 has an annular skirt portion 15a extending from its outer peripheral edge toward the rear in the excavation direction X, and this annular skirt portion 15a is arranged so as to cover the tip portion of the positioned elastic sleeve member 14 on the front side in the excavation direction X from the outside.

[0024] In the fluidizing liquid material supply structure 10 of this embodiment, the guide wall portion 13 is provided with a tapered wall surface portion 13a that widens in diameter toward the front side in the excavation direction X.

[0025] In this embodiment, the mud pressure shield machine 30 is, for example, a pivoting type, as shown in Figures 1 and 2, and as described above, has the same structure as known mud pressure shield machines. In addition to the rotating cutter 32, bulkhead 35, cutter chamber 31, and cutter drive unit 34, the shield machine 30 also includes a forward section outer shell 37a, a rear section outer shell 37b, a shield jack 38, a pivoting jack 39, a rotary join 40, and an erector 41. Segments 42 are assembled into a ring shape inside the rear section outer shell 37b by the erector 41 to sequentially form a primary lining 43. By extending the shield jack 38 while receiving a reaction force from the primary lining 43 made of the formed segments 42, the shield machine can advance in the excavation direction X while cutting the ground at the tunnel face 33 with the rotating cutter 32.

[0026] In this embodiment, the rotary cutter 32 rotates together with the rotary shaft 40b of the rotary join 40 by integrally joining the circular base 32a to the tip of the rotary shaft 40b, which is provided extending from the housing 40a of the rotary join 40 fixed to the central part of the surface on the rear body outer shell 37b side of the partition 35 and penetrating the partition 35 into the cutter chamber 31. In this embodiment, four cutting spokes 32b, to which cutting bits 32h are fixed, are attached as a single unit, extending in all directions in a cross shape from the circular base 32a of the rotary cutter 32, and a center bit 32d is attached as a single unit, protruding in a mountain shape from the central part where the circular base 32a of the rotary cutter 32 is provided forward in the excavation direction X. In this embodiment, the fluidized liquid material supply section structure 10 is provided as a structure of the above-mentioned two supply sections 32c (see Figure 2) arranged in a total of two locations, for example, one location in the central part of the circular base part 32a of the rotating cutter 32, at a position that partially overlaps with the center bit 32d when viewed from the front side, and one location at the radially outer end portion of a selected one of the four cutting spokes 32b.

[0027] Furthermore, in this embodiment, the four cutting spokes 32b are provided with rotating and moving rods 32e, which extend rearward in the excavation direction X and are attached with their rear ends joined to annular rotatable rail members 46 of the rotary drive mechanism 45 (see FIG. 1). The annular rotatable rail member 46 is engaged, for example, by a gear mechanism, with the cutter drive device 34, preferably a hydraulic motor, fixed to the partition wall 35 inside the connection box 47. This allows the rotational drive force from the cutter drive device 34 to be transmitted to the four cutting spokes 32b via the annular rotatable rail member 46 and the rotating and moving rods 32e, rotating the rotary cutter 32 stably with a predetermined torque and enabling the cutting bits 32h and center bits 32d to efficiently cut the ground at the cutting face 33.

[0028] In this embodiment, as described above, the fluidized liquid material supply structure 10 is provided as a structure of a fluidized liquid material supply section 32c (see Figure 2) arranged in two locations, for example, the central portion of the circular base portion 32a of the rotating cutter 32 and the tip portion of a selected cutting spoke 32b, and as shown in Figures 3 and 4(a), it comprises a topped cylindrical discharge cylinder 11 having a plurality of liquid material discharge openings 12 on its side surface 11a and a closed tip portion 11b, a guide wall portion 13 provided on the outside of this discharge cylinder 11, an elastic sleeve member 14 attached in close contact with the side surface 11a of the discharge cylinder 11, and a nut-shaped member 15 screwed onto the tip portion of the discharge cylinder 11.

[0029] The discharge cylinder 11 is a cylindrical metal member having an inner diameter of, for example, about φ50 mm, and the discharge hardware 18, which is integrally molded with the guide wall 13 via the base 17, is fitted into a fitting hole 19 formed in the circular base 32a of the rotating cutter 32 or in a selected cutting spoke 32b, and the peripheral portion is fixed to the inner surface of the fitting hole 19, for example by welding, so that at least the tip 11b of the discharge cylinder 11 protrudes from the surface of the circular base 32a or cutting spoke 32b of the rotating cutter 32, and is attached as a single unit to the rotating cutter 32. The hollow interior of the discharge cylinder 11 communicates with the supply pipe 20 for the fluidized liquid material that passes through the rotary cutter 32 and the rotary shaft 40b of the rotary join 40 via a communication hole 17a formed through the base plate 17, and the discharge cylinder 11 is a topped cylindrical body with the tip 11b closed by a top plate. On the side peripheral surface 11a of the discharge cylinder 11, a plurality of liquid material discharge openings 12 are formed, for example, circular openings with an inner diameter of about φ20 mm, preferably at four locations spaced at 90-degree intervals in the circumferential direction.

[0030] This allows the fluidizing liquid material, which is pressure-fed through the supply pipe 20 and preferably contains a mud-making agent as a plastic fluidizing agent, to be forcefully sprayed in all directions from the four liquid material discharge openings 12.

[0031] In this embodiment, the elastic sleeve member 14, which is attached in close contact with the side surface 11a of the discharge cylindrical body 11, is preferably formed using natural rubber having a hardness of A55 to A75 according to JIS K 6253 as the elastic material. As shown in FIG. 4(b), the elastic sleeve member 14 is preferably formed into a cylindrical shape using natural rubber having a thickness of approximately 5 to 10 mm, with an inner diameter equal to or slightly smaller than the outer diameter of the discharge cylindrical body 11 and a length similar to the length of the discharge cylindrical body 11 excluding the tip portion 11b on which the male thread ridge is formed. The elastic sleeve member 14 is attached in close contact with the entire side surface 11a of the discharge cylindrical body 11 while elastically deforming, covering from the outside the four liquid material discharge openings 12 formed on the side surface 11a.

[0032] When fluidizing liquid material is supplied from the rotary cutter 32 toward the excavation face 33, the fluidizing liquid material is discharged from each of the liquid material discharge openings 12 while elastically deforming the elastic sleeve members 14 to lift them due to the pressure of the supply pipe 20. The discharged fluidizing liquid material is also lifted by the pressure of the supply pipe 20 and is pressure-fed toward the front and rear ends of the elastic sleeve members 14 through the gap between the lifted elastic sleeve members 14 and the side peripheral surface 11a of the discharge cylinder 11. In this embodiment, the fluidizing liquid material is then sprayed mainly from the rear end of the elastic sleeve members 14 by the action of the nut-shaped member 15 described below. The fluidizing liquid material sprayed from the rear end is guided by the guide wall 13 provided on the outside of the discharge cylinder 11, changes direction, and is sprayed forcefully toward the excavation face 33 ahead in the excavation direction X.

[0033] As described above, the guide wall 13 provided on the outside of the discharge cylinder 11 is a metal part molded integrally with the discharge cylinder 11 as part of the discharge hardware 18. The guide wall 13 is provided as an annular part arranged concentrically with the discharge cylinder 11 on the outside of the discharge cylinder 11 by fixing the discharge hardware 18 to fitting holes 19 formed in the circular base 32a and cutting spokes 32b of the rotary cutter 32. The guide wall 13 has the function of guiding the fluidizing liquid material sprayed backward in the excavation direction X from the rear end of the elastic sleeve member 14 so that it changes direction along the inner circumferential surface, including the bottom, of the guide wall 13, and spraying the fluidizing liquid material toward the excavation face 33 ahead in the excavation direction X.

[0034] In addition, in this embodiment, the guide wall portion 13 preferably has a tapered wall portion 13a that expands from the base end connected to the base plate portion 17 of the discharge portion hardware 18 toward the front side in the excavation direction X, thereby enabling the fluidized liquid material that is sprayed from the rear end of the elastic sleeve member 14 toward the rear in the excavation direction X and then redirected to be sprayed in all directions over a wider area toward the face portion 33 forward in the excavation direction X.

[0035] The nut-shaped member 15, threaded onto the tip of the discharge cylinder 11, is a metal fitting with a central threaded opening with a female thread ridge (not shown) formed on its inner circumferential surface. The nut-shaped member 15 also has an annular skirt portion 15a extending rearward in the excavation direction X from its outer periphery. The female thread ridge on the inner circumferential surface of the threaded opening of the nut-shaped member 15 is threaded onto a male thread ridge (not shown) formed on the side circumferential surface 11a of the closed tip portion 11b of the discharge cylinder 11. This allows the inner surface of the nut-shaped member 15, rearward in the excavation direction X, to abut against the tip surface of the elastic sleeve member 14, which is preferably attached to the side circumferential surface 11a of the discharge cylinder 11. This makes it possible to position the elastic sleeve member 14 so that it does not shift when the shield machine 30 excavates while rotating the rotary cutter 32.

[0036] Furthermore, when the nut-shaped member 15 is screwed onto the tip end portion 11b of the discharge cylindrical body 11, the annular skirt portion 15a is arranged to cover from the outside the tip end portion of the positioned elastic sleeve member 14 that is on the front side in the excavation direction X. In this embodiment, the annular skirt portion 15a is arranged to cover from the outside the tip end portion of the elastic sleeve member 14 while maintaining a gap between it and the outer circumferential surface of the tip end portion of the elastic sleeve member 14. The annular skirt portion 15a can also be attached preferably with its inner circumferential surface in close contact with the outer circumferential surface of the tip end portion of the elastic sleeve member 14 (see FIGS. 5(a) and 5(b)).

[0037] The annular skirt portion 15a of the nut-shaped member 15 is arranged to cover the liquid material discharge opening 12 and to externally cover the tip portion of the elastic sleeve member 14 attached to the discharge cylinder 11. As a result, when the shield machine 30 is advanced in the excavation direction X and the rotary cutter 32 cuts the ground at the face 33 while spraying fluidizing liquid material, the cut earth and sand must move around the annular skirt portion 15a and move forward in the excavation direction X before reaching the forward end of the elastic sleeve member 14 in the excavation direction X. This prevents the cut earth and sand from reaching the gap at the forward end of the elastic sleeve member 55 in the excavation direction X, effectively preventing the cut earth and sand from entering the gap at the forward end of the elastic sleeve member 55 in the excavation direction X that is turned up during discharge and causing blockage.

[0038] Therefore, according to this embodiment, with a simple configuration in which only the annular skirt portion 15a is provided on the nut-shaped member 15, when the mud pressure type shield tunneling machine 30 is advanced in the excavation direction X, fluidizing liquid material is sprayed, and the ground at the face portion 33 is cut with the rotating cutter 32, it is possible to effectively prevent the cut earth and sand from entering the gap at the end of the elastic sleeve member 14 on the forward side in the excavation direction X.

[0039] Furthermore, if the inner surface of the annular skirt portion 15a of the screwed nut-shaped member 15 is kept in close contact with the outer surface of the tip portion of the elastic sleeve member 14 (see Figures 5(a) and (b)), the cut earth and sand will be blocked from moving around the annular skirt portion 15a and forward in the excavation direction X, and it will be even more effective to prevent the cut earth and sand from getting into the gap at the end of the elastic sleeve member 14 on the forward side in the excavation direction X.

[0040] In this embodiment, the fluidizing liquid supply structure 10 in the supply section 32c (see FIG. 2) located in the center of the circular base section 32a of the rotary cutter 32 has the discharge cylinder 11 protruding from the circular base section 32a in a trapezoidal cutout 32f provided in the rear part of the center bit 32d in the excavation direction X, so that it is positioned so as to overlap with the center bit 32d when viewed from the front. This allows the center bit 32d to function as a buffer wall member, and effectively alleviates the direct load of cutting pressure on the central supply structure 10 when the rotary cutter 32 cuts the ground at the face 33 while the mud pressure shield machine 30 is advanced in the excavation direction X.

[0041] 2 and 4(a), a belt-shaped buffer wall member 32g can be attached to the fluidizing liquid material supply structure 10 in the supply section 32c where the end portion of the selected cutting spoke 32b is located, by extending it radially from the discharge cylinder 11 and positioning it so that it overlaps with the discharge cylinder 11 when viewed from the front in the excavation direction X, with a gap maintained between the inner peripheral surface of the belt-shaped buffer wall member 32g and the tip end 11b of the discharge cylinder 11. This makes it possible, by the function of the belt-shaped buffer wall member 32g2d, to effectively alleviate the pressure during cutting that is directly applied to the supply structure 10 at the end portion of the cutting spokes 32b when the rotating cutter 32 cuts the ground at the face 33 while the mud pressure shield machine 30 is advanced in the excavation direction X.

[0042] Figures 5(a) and (b) illustrate fluidizing liquid material supply structure structures 10' and 10" according to other embodiments of the present invention. In the fluidizing liquid material supply structure 10' shown in Figure 5(a), the elastic sleeve member 14' has a radially two-layer structure, for example, with soft rubber 14a on the inside and hard rubber 14b on the outside, and is designed to prevent backflow of soil and sand by utilizing the difference in the contraction speed of the rubber. In the fluidizing liquid material supply structure 10" shown in Figure 5(b), the elastic sleeve member 14" has an axially three-layer structure, for example, with hard rubber 14c on both ends and soft rubber 14a in the center, and is designed to prevent backflow of soil and sand by ejecting fluidizing liquid material from the center. The other configurations are the same as those of the above embodiment.

[0043] The fluidized liquid material supply structure 10', 10'' using these elastic sleeve members 14', 14'' also achieves the same effects as the fluidized liquid material supply structure 10 of the above embodiment.

[0044] The present invention is not limited to the above-described embodiment and various modifications are possible. For example, the guide wall does not necessarily have to have a tapered wall surface portion that widens toward the front in the excavation direction.

[0045] 10, 10', 10" Fluidized liquid material supply structure 11 Discharge cylinder 11a Side surface 11b Tip 12 Fluid discharge opening 13 Guide wall 13a Tapered wall portion 14, 14', 14" Elastic sleeve member 15 Nut-shaped member 15a Circular skirt 18 Discharge part metal fittings 19 Fitting hole 20 Supply pipe 30 Mud pressure shield tunneling machine 31 Cutter chamber 32 Rotating cutter 32a Circular base 32b machined spokes 32c supply section 32g Belt-shaped buffer wall material 33 Face 34 Cutter drive unit 35 Bulkhead X Excavation direction

Claims

1. In a mud pressure type shield tunneling machine that cuts the ground with a rotary cutter while stabilizing the face with mud filled in a cutter chamber, a supply unit structure for supplying fluidized liquid material that generates plastically fluidized mud toward the ground at the face, The device is configured to include a cylindrical discharge cylinder with a top that is connected to the fluidized liquid material supply pipe and protrudes forward from the rotating cutter in the excavation direction, has a plurality of liquid material discharge openings on its side circumferential surface, and has a closed tip, guide wall portions that are annularly provided at intervals on the outside of the discharge cylinder, and an elastic sleeve member that covers the plurality of liquid material discharge openings and is attached in a state of tight contact with the side circumferential surface of the discharge cylinder, the elastic sleeve member is positioned on the side circumferential surface of the discharge cylindrical body by a nut-shaped member having a female thread ridge formed on its inner circumferential surface being screwed onto a male thread ridge formed on the side circumferential surface of the tip portion of the discharge cylindrical body, The nut-shaped member also has an annular skirt portion extending from its outer peripheral edge toward the rear in the excavation direction, and the annular skirt portion is arranged to cover from the outside the tip portion of the positioned elastic sleeve member on the front side in the excavation direction, thereby forming a fluidized liquid material supply structure in a shield tunneling machine.

2. 2. A structure of a supply section for fluidizing liquid material in a shield tunneling machine according to claim 1, wherein the guide wall section has a tapered wall surface section whose diameter expands forward in the direction of tunneling.

3. 3. A fluidizing liquid material supply structure for a shield tunneling machine according to claim 1 or 2, wherein the elastic sleeve member is made of natural rubber having a hardness of A55 to A75 according to JIS K 6253.

4. 4. A fluidizing liquid supply structure for a shield tunneling machine according to claim 3, wherein the natural rubber has a thickness of 5 to 10 mm.

5. A fluidized liquid material supply section structure for a shield tunneling machine as described in claim 1 or 2, wherein the annular skirt portion of the nut-shaped member is attached with its inner surface in close contact with the outer surface of the tip portion of the elastic sleeve member at the front side in the tunneling direction.

6. A fluidized liquid material supply section structure for a shield tunneling machine as described in claim 1 or 2, wherein both ends are joined to the rotating cutter, and a band-shaped buffer wall member extends radially of the discharge cylinder, and is attached so as to overlap the discharge cylinder when viewed from the front in the excavation direction, with a gap maintained between its inner surface and the tip of the discharge cylinder.

Images