Method and apparatus for excavating a shaft and tunnel

Abstract: A shield excavator (4) is mounted in a seal body (9) which is rotatably mounted in a cylindrical skin plate (5) supported by a shield frame (8). A shaft (1) is excavated by propelling the shield frame (8) downwards and the seal body (9) is then pivoted in the skin plate (5) to orient the shield excavator (4) substantially horizontally and the shield excavator (4)is then propelled through an opening (26) in the side of the skin plate to excavate a tunnel (2).

Description: The present invention relates to a method and an apparatus for excavating a shaft and a tunnel. Figure 1 is a diagrammatic side sectional view of the conventional method of excavating a shaft and tunnel. The shaft a is excavated using a drive or caisson method and then a shield excavator is moved to the bottom of the shaft and used to excavate the tunnel. In this conventional method, it is disadvantageous to have to move the excavator into the shaft. A further problem is that separate machines for excavating the shaft and tunnel must be provided which increases costs. Having regard to these drawbacks, it is the primary object of the present invention to provide a method and apparatus with a which a shaft and a tunnel may be excavated using a single machine without substantial interruption between the excavation of the shaft and the tunnel. According to the present invention a method of excavating a shaft and tunnel is characterised by the steps of propelling a shield excavator, pivotally mounted on a shield frame, downwardly and excavating the shaft, pivoting the shield excavator with respect to the frame so that it faces in the direction in which the tunnel is to be excavated and propelling the shield excavator without the shield frame in the said direction and excavating the tunnel. Thus in the method in accordance with the invention, only a single excavator is used which is initially mounted on a shield frame, conveniently within a part cylindrical skin plate connected to the shield frame. The shield excavator includes a cutter having either a removable outer cutter or a retractable overcutter, and is initially directed towards and urged in the downward direction to excavate the shaft. The shield excavator progressively moves downwards with the skin plate and shield frame until the desired depth of the shaft is reached. The shield excavator, which is pivotally mounted on the shield frame, preferably by way of the skin plate, is then pivoted so as to be directed in the direction in which the tunnel is to extend and is then urged in that direction to excavate the tunnel. The invention also embraces an apparatus for carrying out such a method and thus an apparatus for excavating a shaft and tunnel of the type including a shield excavator is characterised by an at least part-cylindrical skin plate mounted on a shield frame and means for propelling the shield frame and skin plate downward, a part-spherical seal body mounted in the skin plate so as to be pivotable about a substantially horizontal axis, a seal located between the seal body and the skin plate and an inner skin plate section which is movably supported in the body and which supports the shield excavator the shield excavator having a cutter with a retractable overcutter or with a removable outer cutter. The means for propelling or urging the shield frame, and thus also the skin plate and shield excavator, downwards preferably comprises descending jacks. The apparatus also preferably includes means, e.g. jacks, for moving the inner skin plate section and shield excavator relative to the seal body. Thus, in use, when the shaft has been excavated to the desired depth, the seal body is pivoted relative to the skin plate with the shield excavator within it and the shield excavator and inner skin plate section are then moved out of the seal body and commence excavation of the tunnel. In distinction to the known method of excavating a shaft and tunnel, the step of moving the shield excavator to the bottom of the shaft is eliminated and it is not necessary to provide separate excavators for excavating the shaft and tunnel. The apparatus and method of the present invention thus provide a substantial saving in terms of cost and operating convenience. Further features and details of the invention will be apparent from the following description of certain exemplary embodiments which is given by way of example with reference to Figures 2 to 17 of the accompanying drawings, in which: Figure 2 is a side sectional view of a first embodiment of the present invention; Figure 3 is a front elevation, partly cut away, of the excavator of Figure 2 pivoted into position for excavating a tunnel; Figure 4 is a view from below of the excavator of Figure 2; Figures 5 to 7 are side views of the excavator of Figure 2 showing various stages of pivotal movement of the excavator and the seal body; Figures 8 to 10 are side views of the second embodiment of the invention showing the seal body and the excavator at various stages of pivotal movement ; Figures 11 to 13 are side sectional views of a third embodiment of the invention at various stages of pivotal movement; Figure 14 is a side sectional view of a fourth embodiment of the invention; and Figures 15 to 17 are schematic views of a fourth embodiment of the invention at successive stages of excavation of a shaft and tunnel. The excavation apparatus for excavating a shaft 1 and tunnel 2 shown in Figures 2 to 4 has a main body comprising a shield excavator 4 with a cutter 3, the main body being received in a cylindrical skin plate 5 during the shaft excavation operation. The excavator 4 is housed during excavation of the shaft 1 in a part-spherical seal body 9 which is mounted below a shield frame 8. The shield frame 8 is integral with the skin plate 5 and, in use, may be urged downwards by descending jacks 7 which act against shaft lining segments 6 placed around the shaft in order to produce a downward force on the frame 8. The seal body 9 is dimensioned to be housed within the skin plate 5. The seal body 9 vertically movably supports an inner skin plate section 28 through a peripheral seal member 10 at the lower edge of the body 9. As shown in Figure 3, the seal body 9 has right and left supports 12 which are fitted over supporting pivots 11 which extend from opposite sides of the inner surface of the skin plate 5. The seal body is thereby pivotable about a horizontal axis 13, perpendicular to the vertical axis 5' of the skin plate 5, so that the excavator 4 can be pivoted together with the seal body 9 through 90° into an orientation suitable for excavating a horizontal tunnel 2 (that is to say the orientation in which the cutter 3 faces the left in Figure 2; the left and right sides of Figure 2 are referred to hereafter as the front and rear sides, respectively). The lower portion of the seal body 9 is cut away horizontally to expose the cutter 3 and a further portion is removed from its upper rear side above the horizontal line 13, thereby defining an opening 14. The seal body thus comprises front and rear seal sections 15 and 16. That part of the front seal section 15 between the horizontal plane including the line 13 and the upper edge of the opening 14 is composed of a plurality of detachably interconnected plate segments 17 which abut along lines defined by the intersection of the seal body with respective planes which include the line 13. A peripheral seal member 18 inclined upwardly and forwardly at about 45° is connected to the skin plate 5 and frame 8 and extends around the outer surface of the seal body 9 and forms a seal between the seal body 9 and the skin plate 5 and frame 8. The shield frame 8 has jacks 19 and 20 which may be detachably connected to the plate segments 17 of the front and rear seal sections 15 and 16, respectively, and are used to swing the seal body 9 about the pivots 11. As shown in Figure 4, the cutter 3 comprises an inner cutter 21 and an outer cutter 23 which is detachably engaged with the outer periphery of the inner cutter 21 by couplings 22 in the cutter 21. The outer diameter of the outer cutter 23 is equal to that of the skin plate 5. The cutters 21 and 23 are rotated by a rotary drive 24 on the excavator 4 and are vertically movable by an elevating mechanism 25. The lower end of the skin plate 5 extends to the outer cutter 23 and its front end is cut away generally in the shape of an inverted U at 26 to allow excavation of the tunnel 2. Reference numeral 27 denotes jacks which are used to advance the excavator 4 horizontally out of the seal body to excavate the tunnel 2. When excavating the shaft 1 and the tunnel 2, as shown in Figure 2, the whole excavation apparatus is located or installed such that the excavator 4 is directed downwardly and is pivotable into the direction in which it is desired to excavate the tunnel 2. The cutter 3 is driven while the jacks 7 are activated to urge the excavator downwardly until the shaft 1 has been excavated to the desired depth. As the excavator 4 moves downwardly, the frame 8 and skin plate 5 move with it. Loose earth and sand produced by the excavator are readily dischargeable through the opening 14 up to the ground surface. The loose earth and sand are prevented from intruding into the upper portion of the excavator 4 since the seal body 9 is sealed by the seal 18 with respect to the skin plate 5 and the shield frame 8. After the shaft 1 has been excavated to the desired depth, excavation of the tunnel 2 is started. Firstly, the couplings 22 are retracted to separate the outer cutter 23 from the inner cutter 21. Then, the elevating mechanism 25 is activated to raise the inner cutter 21 into the seal body 9. The inner cutter 21 is sized to be capable of being enclosed within the hypothetical spherical surface R of which the seal body 9 forms part. Thereafter, the jacks 19 and 20 are extended to cause the seal body 9 to swing or pivot about the axis 13 through an arc of a length equal to one plate segment 17, as shown in Figure 5, and are then disconnected from the associated plate segments 17. The plate segment 17 disconnected from the jack 19 is also disconnected from the front seal section 15 and is connected to the rear seal section 16 and to the jack 20. The jack 19 is connected to the succeeding plate segment 17 of the front seal section 15. The jacks 19 and 20 are then again extended to rotate the seal body 9 through an arc equal to one plate segment 17. As shown in Figure 6, this operation is repeated until the excavator 4 is horizontally directed, as shown in Figure 7. Then, unnecessary component parts are removed and various necessary component parts are added to the apparatus. Back anchors 29 are attached to the inner surface of the skin plate 5 and the rear seal section 16. The jacks 27 urge the excavator 4 horizontally forwards and the reaction forces from the jacks are received by the back anchors 29. The excavator 4 and the inner skin plate 28 thus leave the seal body 9 and pass through the opening 26 in the skin plate 5 and commence excavation of the tunnel 2. Whilst the tunnel 2 is excavated, a seal is maintained at the inner skin plate section 28. In this operation, especially during pivoting of the excavator 4, the latter is completely enclosed within the hypothetical surface R so that pivoting of the excavator 4 can be carried out using relatively little force and in a simple manner. When pivoting the excavator 4, the plate segments 17 are sequentially disconnected from the front seal section 15 and connected to the rear seal section 16 so that the opening 14 is always maintained large enough to ensure a sufficient working space. Due to the seal between the body 9 and the seal member 18, intrusion of excavated earth and sand into the upper portion of the space defined by the skin plate 5 is prevented. In the above description, the outer cutter 23 has been described as disconnectable. Alternatively, the inner cutter 21 may be provided with an over-cutter which can be extended and retracted. A vertical movable sheath pipe 5A (see Figure 2) may be provided to surround the skin plate 5 in order to relieve resistance encountered when excavating the shaft. The sheath pipe may be connected to the skin plate. The second embodiment shown in Figures 8 to 10 includes an inner shell 30 which takes the form of the frustum of the sphere obtained by cutting away upper and lower portions of the sphere above and below the horizontal line 13. The shell is pivotable about the axis 13 and the shield excavator 4 is disposed within it. An outer shell 31 also takes the form of a frustum of a sphere and has a height or axial dimension greater than that of the inner shell 30 and is fitted over the inner shell 30. The second embodiment thus has a double-shell part-spherical seal body 32. The outer shell 31 is also pivotable about the line 13 whilst remaining in engagement with the seal member 18, as described above with reference to Figure 1. Reference numeral 33 denotes an opening or space above the outer shell 31. Figure 8 shows the excavator and seal body at the base of a shaft 1 which has just been excavated, with the excavator 4 still directed downwardly and the peripheral seal member 18 in contact with the front upper and rear lower sides of the outer shell 31. The excavator may now rotate into the orientation necessary for excavating a tunnel. Firstly, a jack (not shown) between the outer and inner shells 31 and 30 causes the inner shell 30 to swing into the position shown in Figure 9. Then, a jack (not shown) between the shield frame 8 and the outer shell 31 causes the outer shell 31 to swing into the position shown in Figure 10. The inner shell 30 is then caused to pivot again with respect to the outer shell 31 into the position shown in Figure 10, in a manner substantially similar to that described above, thereby locating the excavator 4 with its cutter directed horizontally. The pivoting operation for the inner and outer shells 30 and 31 is then complete. The excavator 4 is contained within the imaginary spherical surface R of which the inner shell 30 forms part; this facilitates the pivotal movement since it is unobstructed. The pivotal movement can be carried out whilst maintaining the space 33 and the seal is maintained between the double-shell seal body 32 and the peripheral seal member 18. Figures 11 to 13 show a third embodiment of the present invention in which the shield excavator 4 is surrounded wholly by a single, almost wholly spherical seal body 35 except for an upper opening 34 and a lower cut away portion from which the excavator 4 protrudes. The cutter 3 has an over-cutter 36 which is retractable within the imaginary surface R of the sphere of which the seal body 35 forms part. The lower or cutting surface of the cutter is part-spherical. Reference numeral 37 represents swing jacks in the seal body 35; 38, a guide plate at the rear side of the shield frame 8; and 39, means for receiving the reaction force from the jacks 37. When the excavator 4 is to be swung out of the position shown in Figure 11, the over-cutter 36 is firstly retracted and the reaction force receiving means 39 is attached to the guide plate 38 at the opening 34. The jacks 37 are extended with the reaction forces being received by the receiving means 39 so that the seal body 35 is caused to swing through a predetermined angle; then, the attachment position of the receiving means 39 is moved around the guide plate 38, as shown in Figure 12. This operation is carried out repeatedly until the excavator 4 is oriented with the cutter facing horizontally, as shown in Figure 13. A working opening 40 as shown in Figure 3 is produced so that the opening 34 is now directed horizontally away from the shield frame 8. The shield excavator 4 is again housed within the imaginary spherical surface R of which the seal body 35 forms part, which again facilitates the pivotal movement of the excavator 4. The pivotal movement can be carried out while sealing is maintained between the seal body 35 and the peripheral seal member 18. The fourth embodiment illustrated in Figures 14 to 17 includes a shield excavator 41, having a cutter 3, which forms the main body of the apparatus for excavating a shaft 1 and a tunnel 2. The excavator 41 is suspended from its upper end by supporting pivots 11 on the leading end portion of the skin plate 5 during excavation of the shaft. The leading or lower portion of the skin plate 5 is cut away above the pivots 11 at 45° and a closing plate 44 is located over it; the inner skin plate section 28, which constitutes the wall of the excavator 41, has a 45° portion cut away from its upper side adjacent the closing plate 44, starting from the region adjacent the pivots 11 and extending downwardly. The section 28, including the cut away portion, is enclosed within the cover 45. Thus, space 46 which allows the excavator to be pivoted is defined between the portion 45a of the cover 45, which overlies the cut away portion of the section 28, and the closing plate 44, so that the excavator 41 can be swung through 90° in one direction (into the forward orientation), about the pivots 11, by means of two jacks 42 and 43 (see also Figure 15). The cutter 3 is driven by a drive 24 on a bulkhead 47 and is provided with an over-cutter 49 located along the outer periphery of a cutter frame 48. Mounted on the cover portion 45a is a part-spherical first seal body 50A which comprises a part-spherical arcuate portion 50a whose centre is on the axis of the pivots 11, and which extends from the cover portion 45a through the closing plate 44. The first seal body 50A further comprises an end plate 50b which connects the other end of the arcuate portion 50a with the pivots 11, and extends coplanar with the plate 44, and comprises side plates 50c which close or complete the frame structure defined by the plates 50a and 50b. Mounted on the upper end of the excavator 41 is a second part-spherical seal body 50B whose centre is at the intersection of the axis of the inner skin plate section 28 with the axis of the pivots 11 and which is integral with the seal body 50A. On pivoting of the excavator 41, the seal body 50A is rotated whilst being guided through an opening in the closing plate 44. Simultaneously, the seal body 50B is slidably guided by the inner surface of the skin plate 5. Thus the pivoting of the excavator 41 is carried out smoothly and the space defined between the seal bodies 50A and 50B forms a passage 51 which communicates between the interior of the inner skin plate section 28 and the interior of the skin plate 5. Reference numeral 52 designates a seal member disposed on the closing plate 44 which seals with the seal body 50A where it passes through the closing plate. 53 designates a seal member which is disposed inside the leading portion of the skin plate 5 and serves to seal against the sliding surface of the seal body 50B. A sheath pipe 54 is provided to maintain alignment of the axis of the excavator 41 with that of the skin plate 5. The sheath pipe 54 surrounds the excavator 41 and the outer cylindrical surface of the skin plate 5. A hydraulic jack-type knock or projection 55, which is extendable into and retractable from the sheath pipe 54 through the skin plate 5, is mounted on the inner wall surface of the skin plate 5 and serves as means for engaging and disengaging the sheath pipe 54 with the skin plate 5. A wire rope 57 engages at its lower end with the rear end of the sheath pipe 54 so that the latter, when disengaged from the skin plate 5, may be lifted up to the surface by means of a winch 56 installed at the surface. During excavation, the alignment of the shield excavator 41 with the skin plate 5 is maintained by the sheath pipe 54. As shown in Figure 14, the apparatus is so arranged that the excavator 41 is directed downwardly during excavation of the shaft and is then pivotable into a suitable orientation for excavating the tunnel 2. Excavation of the shaft 1 to a predetermined depth is carried out by driving the cutter 3 while downward thrust forces are imparted by the jacks 7. In this case, when the excavator 41 approaches the level to which the top of the tunnel 2 is to come, the over-cutters 49 are extended radially outwardly from the outer periphery of the cutter frame 48 on the side of the frame on which the tunnel is to be excavated. The ground on one side of the seal body 50A is thus excavated to provide a space through which the excavator 41 can be pivoted. Loose earth and sand produced when excavating the shaft 1 are readily discharged up to the surface since the interior of the inner skin plate section 28 communicates with the interior of the skin plate 5 through the passage 51 defined by the seal bodies 50A and 50B. Even when loose earth and sand pass through the space between the wall of the pipe 54 and the wall of the inner skin plate section 28 into the interior of the sheath pipe 54, they cannot intrude to the interior of the plate section 28 and the skin plate 5 so that the plate section 28 is covered by the cover 45 and the interior of the skin plate 5 is closed by the closing plate 44 and the seal members 52 and 53 which engage the sliding portions of the seal bodies 50A and 50B. In order to excavate the tunnel 2, the knock 55 is retracted to disengage the sheath pipe 54 from the skin plate 5. A plurality of winches 56, installed at the surface, are used to wind in the wire ropes 57 which are securely fixed to the sheath pipe 54 thereby lifting it. Simultaneously, the over-cutter 49 is retracted. Then the cutter 3 is driven to dig the ground in front of it while the jack 42 connecting the shield frame 8 to the seal body 50A is extended to pivot the excavator 41. In this case it is impossible to pivot the excavator 41 through 90° using only one jack 42; therefore, as shown in Figure 15, an additional jack 43 is used and the operation of the jacks 43 and 42 is alternated to swing the excavator 41 through 90° so that it faces in the direction in which the tunnel 2 is to be excavated, as shown in Figure 16. The excavator 41 is swung smoothly since the seal body 50A is guided by the opening in the closing plate 44 and the outer surface of the seal body 50B is guided by the inner surface of the skin plate 5. Upon completion of the pivotal movement of the excavator 41, a hole is made through, for instance, the seal body 50B and backfill material 58 is injected through this hole to solidify or improve the ground below the excavator 41, as shown in Figure 17. The shield jacks 42 and 43, the seal body 50A, the supporting pivots 11, the cover portion 45a and so on are removed and an additional inner skin plate member 28a is joined to the rear end of the inner skin plate section 28 to extend the latter in the form of a pipe. Within the extended cylindrical inner skin plate section 28, various equipment is disposed such as an elector 59, a shield jack 60 and other items which are required for carrying out an excavation process using a shield excavator. A back anchor 61 is installed to receive the reaction force of the advancing shield jack 60. The excavator 41 is activated again to excavate the tunnel 2 in the conventional manner. Thus, by using only one shield excavator 41, the shaft 1 and the tunnel 2 can be excavated without substantial delay between excavation of the shaft and tunnel. It will be understood that the present invention is not limited to the embodiments described above and that various modifications may be effected. For instance, the sheath pipe 54 may be used in the embodiments described with reference to Figures 2 to 13. The pivotal movement of the excavator 4 or 41 may be carried out by any suitable means instead of by jacks. The excavating material may be discharged to the surface by a liquid transportation system or by a conveyor system. In order to engage and disengage the sheath pipe 54 with and from the skin plate 5, any suitable means may be employed.

Claims: A method of excavating a shaft and a tunnel characterised by using a shield excavator (4;41) having a cutter (3) with a removable outer cutter (23) or a retractable overcutter (36;49), the excavator being pivotally mounted in a shield frame, and further characterised by the steps of propelling the shield excavator (4;41) downwardly and excavating the shaft (1), pivoting the shield excavator (4;41) with respect to the frame (8) so that it faces in the direction in which the tunnel (2) is to be excavated and propelling the shield excavator (4;41) without the shield frame (8) in the said direction and excavating the tunnel (2). Apparatus for excavating a shaft and tunnel including a shield excavator (4;41) characterised by an at least part-cylindrical skin plate (5) mounted on a shield frame (8) and means (6,7) for propelling the shield frame (8) and skin plate (5) downwards, a partspherical seal body (9;32;35;50A,50B) mounted in the skin plate (5) so as to be pivotable about a substantially horizontal axis (13), a seal (18;52,53) located between the seal body (9;32;35;50A,50B) and the skin plate (5) and an inner skin plate (28) which is movably supported in the seal body (9;32;35;50A,50B) and which supports the shield excavator (4;41), the shield excavator (4;41) having a cutter (3) with a retractable overcutter (36;49) or with a removable outer cutter (23). Apparatus as claimed in Claim 2, characterised in that the means (6,7) for propelling the shield frame (8) downwards include descending jacks (7). Apparatus as claimed in Claim 2 or Claim 3, characterised by means (27;60) for moving the inner skin plate (28) and shield excavator (4) relative to the seal body (9;32;35;50A,50B). Apparatus as claimed in any one of claims 2 to 4 characterised by a sheath pipe (5A;54) located around the skin plate (5) which is movable with respect to the skin plate (5) and connectable to it. Apparatus as claimed in any one of claims 2 to 5, characterised in that the shield excavator (4) may be enclosed within the imaginary spherical surface (R) which is defined in part by the seal body (9;32;35). Apparatus as claimed in any one of claims 2 to 6, characterised in that part of the seal body (9) is composed of a plurality of detachably connected plate segments (17) which meet along lines defined by the intersection of the surface of the seal body with respective planes which include the axis (13). Apparatus as claimed in any one of claims 2 to 6, characterised in that the seal body (32) comprises an inner shell (30) in which the shield excavator (4) is supported and which is pivotable with respect to the skin plate (5) and an outer shell (31) which is engaged by the seal (18) and is pivotable both with respect to the inner shell (30) and the seal (18). Apparatus as claimed in any one of claims 2 to 6, characterised in that the seal body (35;50A,50B) is a unitary structure. Excavating apparatus as claimed in any one of claims 2 to 9 characterised by jacks (19,20;37;42,43) arranged to pivot the seal body (9;32;35;50A,50B) with respect to the skin plate (5).

Inventors: BESSHO TOSHIHIKO, INO TOSHIMI, ITO HIROYUKI, KANEKO KENICHI, UEHARA TOSHIAKI, BESSHO, TOSHIHIKO, INO, TOSHIMI, ITO, HIROYUKI, KANEKO, KENICHI, UEHARA, TOSHIAKI
Applicants: ISHIKAWAJIMA HARIMA HEAVY IND, TAISEI CORP, ISHIKAWAJIMA-HARIMA JUKOGYO KABUSHIKI KAISHA, TAISEI CORPORATION
Application year: 1990
Main classification: E21D1
IPC codes: E21D9, E21D1