GB2106161A

GB2106161A - Shield tunnelling machine

Info

Publication number: GB2106161A
Application number: GB08216173A
Authority: GB
Inventors: Tadao Yoshikawa; Shozo Hirata
Original assignee: Hitachi Zosen Corp
Current assignee: Hitachi Zosen Corp
Priority date: 1981-09-18
Filing date: 1982-06-03
Publication date: 1983-04-07
Also published as: DE3222923A1; FR2513309B1; FR2513309A1; ATA348482A; DE3222923C2; GB2106161B; AT375734B

Abstract

A shield tunnelling machine having incorporated therein an earth removing apparatus which comprises a tubular casing 7 having an earth inlet 7a at one end and a closable earth outlet 7b at the other end, and an earth transport conveyor 8 rotatably provided within the casing 7 and comprising a helically twisted strip. Unlike conventional earth removing apparatus for such a machine, which apparatus has a screw conveyor comprising a rotary shaft and a screw blade around the shaft, the present apparatus can transport and discharge earth containing large solid fragments and therefore performs the desired function even when small in diameter, i.e. in shield diameter. <IMAGE>

Description

SPECIFICATION Shield tunneling machine The present invention relates to a shield tunneling machine, and more particularly to a shield tunneling machine including an efficient earth removing apparatus.

When tunnels are formed by a shield excavating machine, the forward ground is excavated with a cutter head attached to one end of its shield main body, and the earth is taken into a pressure chamber behind the cutter head and passed through an earth removing apparatus into an atmospheric pressure chamber in the rear of the pressure chamber. With conventional earth removing apparatus, the earth is transported by a so-cailed screw conveyor which has a screw blade around a rotary shaft, so that the size of stones or rocks that can be transported is limited by the shaft which is a hindrance.Accordingly when the diameter of the shield main body is decreased (to excavate a smaller tunnel), the earth removing apparatus used has a correspondingly decreased diameter and is unable to satisfactorily transport and discharge earth which contains large solid fragments, such as cobbles and boulders.

The object of the present invention is to provide an earth removing apparatus which is capable of efficiently discharging large fragments even when having a diametrically small shield main body.

To fulfill this object, the present invention provides a shield tunneling machine which comprises a hollow shield main body; a cutter head rotatably disposed at one end of the main body; a pressure chamber formed within the main body immediately behind the cutter head; an atmospheric pressure compartment formed within the main body in the rear of the pressure chamber; and an earth removing apparatus provided within the main body and holding the pressure chamber in communication with the atmospheric pressure compartment; the earth removing apparatus comprising a tubular casing having at a front end portion thereof an earth inlet opened to the pressure chamber and at a rear end portion thereof a closable earth outlet communicating with the atmospheric pressure compartment, and an earth transport conveyor rotatably provided within the casing and comprising a helically twisted strip.

Since the earth transport conveyor has no rotary shaft according to the above construction, the apparatus is capable of transporting and discharging earth containing relatively large solid fragments (for example, those having 2/3 the diameter of the casing) even when the shield main body or the tubular casing has a reduced diameter.

Furthermore, the strip, which is helically twisted continuously will not resist the earth greatly and is less prone to abrasion.

According to a preferred embodiment of the invention, the rear end portion of the casing is provided with a poking rod which is movable into the casing for collapsing the mass of earth consolidated in the rear portion. The poking rod is hollow and connected to a slime injecting tube, through which slime can be introduced into the casing rear end portion when so desired to give decreased water permeability and improved flowability to the earth in this portion.

According to another preferred embodiment of the invention, an earth kneading blade comprising a helically twisted strip is rotatably provided within the pressure chamber, whereby the excavated earth is thoroughly kneaded with slime within the pressure chamber and thereby rendered less permeable to water and smoothly transportable before being forced into the earth removing apparatus. Consequently the earth can be transported efficiently without causing wear to the conveyor, while the improved sealing properties of the earth permit the internal pressure of the pressure chamber, as well as of the earth removing apparatus, to build up sufficiently to effectively prevent collapse of the forward ground against its earth pressure.

Various other features and advantages of the invention will be readily understood from the embodiments to be described below with reference to the accompanying drawings, in which: Fig. 1 is a view in longitudinal section showing a shield tunneling machine according to a first embodiment of the invention; Fig. 2a to Fig. 2c are views in section taken along the line Il-Il in Fig. 1 and showing an earth outlet as provided at various positions; Fig. 3 is a view in longitudinal section showing a modification of the first embodiment; Fig. 4 is a view in longitudinal section showing a second embodiment of the invention; Fig. 5 is a view in section taken along the line V-V in Fig. 4; Fig. 6 is a view in longitudinal section showing a modification of the second embodiment; Fig. 7 is a fragmentary enlarged view in section of the same;; Fig. 8 is a view in longitudinal section showing another modification of the second embodiment; and Fig. 9 is a view in longitudinal section showing another modification of the second embodiment.

Throughout the drawings, like parts are referred to by like reference numerals.

With reference to Fig. 1 showing a first embodiment of the invention, indicated at 1 is a hollow shield main body in conformity with the shape of the tunnel to be excavated. A cutter head 2 rotatable by drive means 3 is rotatably mounted on one end (front end) of the main body 1. Formed within the shield main body 1 are a pressure chamber 4 immediately behind the cutter head 2 and an atmospheric pressure compartment 5 in the rear of the chamber 4. The pressure chamber 4 is in communication with the atmospheric pressure compartment 5 through an earth removing apparatus 6. The excavated earth taken into the pressure chamber 4 through slits formed in the cutter head 2 is transported through the apparatus 6 toward the compartment 5.The earth removing apparatus 6 consists essentially of a tubular casing 7 having at a front end portion thereof an earth inlet 7a opened to the pressure chamber 4 and at a rear end portion thereof an earth outlet 7b communicating with the atmospheric pressure compartment 5, and an earth transport conveyor 8 rotatably provided within the casing 7 and comprising a helically twisted strip. The conveyor 8 has one end rotatably supported on the front end of the casing 7 by a bearing 9 and the other end provided with a hollow end shaft 10 which is rotatably supported by a bearing 11 on the rear end of the casing 7.

The conveyor 8 is coupled to drive means 14 by a driven gear 12 fixed to the end shaft 10 and a drive pinion 1 3 meshing with the gear 12. A gate 1 5 for closing the earth outlet 7b is operated by cylinder means 1 6. As seen in Figs. 2a to 2c, the earth outlet 7b can be formed in a lower, lateral or bottom portion of the casing 7 so that the earth will be discharged tangentially of the casing.

The pressure chamber 4 is provided with injection pipes 1 9 in communication therewith for injecting slime into the chamber 4 therethrough. A poking rod 18 slidably extending through the end shaft 10 of the conveyor 8 is movable into the casing 7 by cylinder means 1 7 so that the portion of earth consolidated in the rear portion of the casing 7 can be collapsed by the poking rod 1 8.

The poking rod 1 8 is connected to a tube 20 through which slime is injected into the casing 7.

The slime mentioned is used to give lubricity to the earth, reduce its shearing force and clog up the interstices between the earth particles.

The earth excavated by the cutter head 2 of the above apparatus is taken into the pressure chamber 4 through the slits of the head 2, forced into the tubular casing 7 along with the slime injected through the pipes 19, transported by the conveyor 8 while being efficiently kneaded, and discharged from the earth outlet 7b. Since the interstices between the particles of excavated earth are clogged up by being thus kneaded with the slime, the earth is made less permeable to water to prevent escape of underground water.

Further because the internal pressure of the chamber 4, as well as the casing 7, can be built up by limiting the amount of discharge of earth with the gate 15, the increased pressure prevents the forward ground from collapsing against its earth pressure. If the excavated earth is consolidated in the rear portion of the casing 7, the mass of earth is collapsed by the poking rod 1 8. When it is required to give sealing properties to the earth in the vicinity of the gate 1 5, slime is injected into the casing through the tube 20 and the poking rod 18.

When the conveyor strip 8 is used, the sizes of cobbles or fragments of rocks that can be discharged are up to as large as the height d of the upper end of the inner periphery of the conveyor strip 8 from the inner bottom surface of the casing 7 as shown in Fig. 2c. Thus the conveyor can handle much larger fragments than the conventional screw conveyor having a rotary shaft.

The modification of Fig. 3 differs from the embodiment of Fig. 1 only in the arrangement for driving the conveyor 8. The conveyor strip 8 is provided at its rear end with a rotary disk 21 approximately equal to the conveyor 8 in outside diameter. An annular member 22 fixed to the outer periphery of the disk 21 has a driven gear 23. The conveyor 8 is coupled to drive means 25 by the gear 23 and a drive pinion 24. A bearing 26 is disposed in an annular recess of the casing 7 for supporting the annular member 22 and is provided with seals 27 on its opposite sides. Since the disk 21 rotates, the poking rod 1 8 is supported by a bearing 28.

With reference to Figs. 4 and 5, a second embodiment of the invention will now be described. The shield tunneling machine of this embodiment essentially differs from those of Figs.

1 and 3 in that in addition to the earth transport conveyor 8, an earth kneading blade 29 is provided for kneading the earth with the slime from the injection pipes 1 9 within the pressure chamber 4 more effectively. More specifically, the kneading blade 29 is in the form of a helically twisted strip surrounding the front end portion of the conveyor 8. The blade 29 has one end rotatably supported by a bearing 30 at the center of rotation of the cutter head 2 and the other end supported by an annular member 31 attached to the outer periphery of the strip 29 and by a bearing 32 on a frustoconical wall 33 defining the pressure chamber 4. The kneading blade 29 is rotated by drive means 36 through a driven gear 34 attached to the annular member 31 and a drive pinion 35.The conveyor 8 is rotatably supported on the casing 7 by an annular member 22 which is attached directly to the outer periphery of the rear end of the conveyor 8. The rear end of the casing 7 has an earth outlet 7b. Although not shown in Figs. 1 and 3, a belt conveyor or like transfer conveyor 37 is actually disposed subsequent to the earth removing apparatus 6 for delivering the excavated earth from the outlet 7b to a suitable location.

Because the second embodiment of the foregoing construction has the earth kneading blade 29, the earth can be thoroughly kneaded with slime before advancing into the apparatus 6 to effectively build up pressure within the pressure chamber 4 and the casing 7 against the collapsing earth pressure of the ground confronting the apparatus.

Fig. 5 shows a modification which differs from the embodiment of Fig. 4 in the arrangement for supporting the earth kneading blade 29. The kneading blade 29 comprising a helically twisted strip has one end rotatably supported by a bearing 38 on the front end of the tubular casing 7 extending into the pressure chamber 4 and the other end rotatably supported on the outer periphery of the casing 7 by an annular member 31 fixed to the inner periphery of the strip 29, a front bearing 39 and a rear bearing 40. As shown in Fig. 7, the rear bearing 40 is a thrust bearing comprising an outer ring 40a fixed to the annular member 31 and an inner ring 40a having an outer peripheral portion in the form of a driven gear 34.

The gear 34 is in mesh with a drive pinion 35 of drive means 36 whereby the blade 29 is rotated.

The inner ring 40b of the rear bearing 40 is supported by a bracket 41 on the casing 7. On the other hand, the earth transport conveyor 8 has one end rotatably supported by a bearing 9 on the front end of the casing 7 and the other end rotatably supported on a rear end portion of the casing 7 by an annular member 22 attached to the outer periphery of the strip 8. Fig. 6 further shows a seal 42 interposed between the casing 7 and the annular member 31, a bearing 43 provided between the annular member 31 and a wall defining the pressure chamber 4, seals 44 provided on the opposite sides of the bearing 43, a support 45 for supporting the apparatus 6 on the shield main body 1 and a scraping blade 46 disposed in the pressure chamber 4.

Fig. 8 shows another modified shield tunneling machine, in which the casing 7 and the earth transport conveyor 8 do not extend into the pressure chamber 4. The kneading blade 29 is supported at only one end by an annular member 31 on the tubular casing 7.

Fig. 9 shows another modification, in which an annular member 31 fixed to the inner periphery of the kneading blade 29 is rotatably supported by a bearing ring 47 fixed to the outer periphery of the casing 7. An oil supply pipe 49 is disposed in an annular space 48 formed between the bearing ring 47 and the casing 7.

The shield tunneling machines shown in Figs. 6 to 9 of course operate in the same manner as the one shown in Fig. 4. Although the machines shown in Figs. 4 to 9 are provided with neither of the slime injecting tube and the poking rod at the rear end of the casing 7, these members can be provided when desired. The kneading blade 29, as well as the transport conveyor 8, may be supported at only one end or at two points as desired.

Claims

1. A shield tunneling machine comprising a hollow shield main body; a cutter head rotatably disposed at one end of the main body; a pressure chamber formed within the main body immediately behind the cutter head; an atmospheric pressure compartment formed within the main body in the rear of the pressure chamber; and an earth removing apparatus provided within the main body and holding the pressure chamber in communication with the atmospheric pressure compartment; the earth removing apparatus comprising a tubular casing having at a front end portion thereof an earth inlet opened to the pressure chamber and at a rear end portion thereof a closable earth outlet communicating with the atmospheric pressure compartment, and an earth transport conveyor rotatably provided within the casing and comprising a helically twisted strip.

2. A shield tunneling machine as defined in claim 1 wherein the front end portion of the casing extends into the pressure chamber along with the front end of the transport conveyor, and the conveyor is rotatably supported at its front end by the front end of the casing and at its rear end by a rear end portion of the casing.

3. A shield tunneling machine as defined in claim 2 wherein the rear end of the conveyor is supported on a rear end wall of the casing by an end shaft attached to the conveyor rear end.

4. A shield tunneling machine as defined in claim 2 wherein the rear end of the conveyor is attached to a rotary disk, and the rotary disk is rotatably supported on the inner periphery of the casing by an annular member fixed to the outer periphery of the disk.

5. A shield tunneling machine as defined in claim 1 wherein the rear end portion of the casing is provided with a poking rod movable into the casing.

6. A shield tunneling machine as defined in claim 5 wherein the poking rod is hollow and has a slime injecting tube connected thereto.

7. A shield tunneling machine as defined in claim 1 wherein an earth kneading blade comprising a helically twisted strip is rotatably provided within the pressure chamber.

8. A shield tunneling machine as defined in claim 7 wherein the conveyor has a front end portion extending into the pressure chamber and surrounded by the earth kneading strip.

9. A shield tunneling machine as defined in claim 7 or 8 wherein the earth kneading strip is rotatably supported on a wall defining the pressure chamber by an annular member attached to the outer periphery of a rear end portion of the earth kneading strip.

10. A shield tunneling machine as defined in claim 9 wherein the front end of the earth kneading strip is rotatably supported at the center of rotation of the cutter head.

11. A shield tunneling machine as defined in claim 7 wherein the earth kneading strip is rotatably supported on the outer periphery of the casing by an annular member attached to the inner periphery of a rear end portion of the earth kneading strip.

12. A shield tunneling machine as defined in claim 11 wherein the front end portion of the casing extends into the pressure chamber along with a front end portion of the conveyor and is surrounded by the earth kneading strip, and the front end of the conveyor is rotatably supported by the front end of the casing together with the front end of the earth kneading strip.

13. A shield tunneling machine as defined in claim 11 wherein the front end of the casing and the front end of the conveyor terminate at the rear end of the pressure chamber.

14. A shield tunneling machine as defined in any one of claims 11 to 13 wherein the conveyor is rotatably supported on the casing by an annular member attached to the outer periphery of the rear end of the conveyor.

1 5. A shield tunneling machine as defined in any one of claims 11 to 14 wherein a front bearing and a rear bearing are provided between the casing outer periphery and the annular member attached to the earth kneading strip, and the rear bearing is a thrust bearing comprising an outer ring fixed to the annular member and an inner ring fixed to the casing outer periphery and rotatable but axially immovable relative to the outer ring, the outer ring having an outer peripheral portion serving as a driven gear in mesh with a drive pinion of drive means.

1 6. A shield tunneling machine as defined in any one of claims 11 to 15 wherein a bearing ring fixed to the casing is provided between the casing outer periphery and the annular member attached to the earth kneading strip to form an annular space between the bearing ring and the casing outer periphery, and the annular space is provided with an oil supply pipe.

1 7. A shield tunneling machine substantially as described herein with reference to, and as illustrated in, Figures 1 and 2; or Figures 1 and 2 as modified by Figure 3; or Figures 4 and 5; or Figures 4 and 5 as modified by Figures 6 and 7 or by Figure 8 or Figure 9, of the accompanying drawings.