JP2009013586A - Removal shield and tunnel removing method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a removal shield and a removal method which enable the easy and inexpensive removal of a tunnel constructed by using an unhardened gel material as a back-filling material. <P>SOLUTION: This removal shield comprises: a tubular skin plate 47 which intrudes into a gap between a segment 8 and the natural ground; seals 21 and 23 for sealing water between the skin plate and an existing segment; a cutting-face holding jack 35 which is provided on the skin plate via a supporting frame 34 and abuts on the front end of the existing segment; a bulkhead 16 for closing a central opening at the other side of the intrusion direction of the skin plate; a nozzle 44 which is provided in the bulkhead so as to infill a back-filling material into a backfilled space 43 ahead of the bulkhead; an earth pressure meter 45 for detecting the pressure of the infilled back-filling material; a control unit which makes a cutting-face holding jack recede so that the backfilled space can be filled with the back-filling material and so that pressure detected by the earth pressure meter can be set at preset and predetermined pressure; and an erector 17 for dismantling the existing segment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a removal shield for removing a tunnel backed with a gel-like backfilling material that does not solidify in a gap between a segment and a natural ground, and a tunnel removal method using the same.

  As the removal shield for refilling the tunnel, those described in Patent Documents 1 to 6 are known. The removal shield described in Patent Documents 1 to 5 surrounds the outer periphery of the existing segment with a cylindrical outer frame, divides the outer frame into a front trunk and a rear trunk, and these front and rear trunks are separated by a propulsion jack. They are connected freely, a partition is provided at the rear end of the rear trunk, and a drilling device such as a cutter is provided at the front end of the front trunk to excavate the ground around the existing segment. The removal shield described in Patent Document 6 is configured to obtain a driving force by gripping the inner peripheral surface of the existing segment. In addition, these removal shields are designed to retract the back jack while pulling back the propulsion jack while filling the backfill space in the backfill space behind the partition wall, and then pull the propulsion jack forward, and then extend the propulsion jack to advance the front trunk It is configured to dig repeatedly.

Japanese Patent No. 3087229 Japanese Patent No. 3721488 Japanese Patent No. 3581619 JP 2001-227300 A JP 2001-107680 A JP 2001-107698 A

  By the way, all of these removal shields are intended to remove a tunnel constructed by filling a hardened backfill material such as mortar between the existing segment and the ground, so excavation equipment and earth removal equipment are required. In addition, the outer diameter of the backfill space is larger than that of the existing segment, and there is a problem that a large amount of backfill material must be filled. Further, the above-described removal shield has a problem that the structure becomes complicated and expensive because the front and rear cylinders are moved close to and away from each other and are excavated in the shape of a scale insect.

  On the other hand, the present inventors pay attention to the fact that the backfilling material that hardens complicates the removal shield and makes it difficult to remove the tunnel. We are researching and developing new tunnel construction methods.

  Accordingly, an object of the present invention is to provide a removal shield capable of easily and inexpensively removing a tunnel constructed by this novel method, and a tunnel removal method using the removal shield.

  In order to solve the above-mentioned problems, the present invention digs up the shield machine while assembling the segments in the shield machine, and backfills the gel-like backing material that does not solidify in the gap between the assembled segment and the ground. A shield for removing the tunnel constructed in this manner, a cylindrical skin plate that penetrates the gap, a seal that stops water between the skin plate and the existing segment, and a support frame on the skin plate via a support frame A face holding jack that is provided in contact with the front end of the existing segment, a partition that closes the central opening opposite to the penetration direction of the skin plate, and a backfill space that is provided in the partition and is embedded in the backfill space portion ahead of the partition A nozzle for filling the return material, and an earth pressure gauge for detecting the pressure of the backfill material filled in the backfill space from the nozzle, A control device for filling the backfilling space from the nozzle with the backfilling material and retracting the face holding jack so that the pressure detected by the earth pressure gauge becomes a predetermined pressure set in advance, and the skin plate And an erector for dismantling the existing segment.

  It is preferable that at least four face holding jacks are arranged at equal intervals in the circumferential direction of the skin plate.

  In addition, the tunnel removal that removes the tunnel built by backing the gel-like backfill material that does not solidify in the gap between the assembled segment and the ground, while digging the shield machine while assembling the segments in the shield machine A face holding jack that is provided with a seal that penetrates a cylindrical skin plate into the gap and that stops water between the skin plate and the existing segment, and is in contact with the front end of the existing segment. Through the support frame, the central opening opposite to the penetration direction of the skin plate is closed with a partition wall, and a nozzle for filling the backfill space in the backfill space ahead of the partition wall is provided in the partition wall. An earth pressure gauge is provided for detecting the pressure of the backfill material filled in the backfill space from the nozzle. An erector for disassembling the existing segment is provided in the inside to constitute a removal shield, and the backfilling space is filled with the backfilling material from the nozzle, and the pressure of the backfilling material in the backfilling space is filled with the earth pressure gauge. When the pressure reaches a predetermined pressure set in advance, the face holding jack is retracted to propel the removal shield so that the pressure is maintained, and the pressure acting on the partition wall is held by the face holding jack. However, the existing segments are sequentially disassembled by the above-mentioned erector.

  At least four face holding jacks are arranged at equal intervals in the circumferential direction of the skin plate, and when the face holding jack abutting on the segment to be disassembled is separated from the segment, the other three or more face holding jacks are held. It is preferable that the pressure of the backfill material in the backfill space can be maintained with a jack.

  ADVANTAGE OF THE INVENTION According to this invention, the tunnel constructed | assembled using the gel-like material which is not hardened for a backfilling material can be removed easily and cheaply.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, an apparatus and parts used for constructing a tunnel using a gel-like material that does not harden as a backfill material will be described.

  As shown in FIG. 1A and FIG. 3F, the shield machine 1 includes a shield frame 2 that is formed in a cylindrical shape, a bulkhead 3 that closes the front end of the shield frame 2, and rotates to the bulkhead 3. A cutter 4 provided freely, a feeding / discharging mud type earth discharging device 6 for discharging the earth and sand in the cutter chamber 5 formed behind the cutter 4, and a shield frame 2 through a support member 7. The shield frame 2 includes an erector 10 for assembling the segments 8 and 9, and a shield jack 11 provided on the support member 7 for taking a driving reaction force from the segments 8 and 9. A plurality of shield jacks 11 are arranged at equal intervals in the circumferential direction. When assembling the segments 8 and 9, the shield jack 11 at the assembly position is degenerated, and the pressure of the face is held by the other shield jack 11. ing.

  Further, the shield machine 1 includes a seal portion 14 that is a component of a removal shield 13 described later, and the removal shield 13 is assembled using the seal portion 14 at an intermediate position of the tunnel constructed by the shield machine 1. It is like that.

  As shown in FIG. 4 (g), the removal shield 13 is provided with a partition wall 16 for closing the central opening at the front end of a cylindrical outer frame 15 that liquid-tightly covers the outer periphery of the end of the existing segment 8, and for disassembling the segment. The erector 17 is provided. The outer peripheral frame 15 is divided into front and rear in advance, and includes a seal portion 14 that constitutes the rear portion and divided blocks 29, 30, 31, and 32 that constitute the front portion.

  The seal portion 14 is formed in a cylindrical shape along the inner peripheral surface of the shield frame 2, and is detachably provided on the inner peripheral surface of the shield frame 2. As shown in FIGS. 1 (a) and 7, the seal portion 14 is formed in a cylindrical shape and the inner diameter of the rear portion is made smaller than the inner diameter of the front portion. A rear skin plate 20 that is inserted into a gap 19 with the mountain 18, a stop seal 21 that is provided on the inner peripheral side of the rear portion of the rear skin plate 20 and seals between the rear skin plate 20 and the existing segment 8, and a rear portion A slide frame 22 that is slidable in the axial direction along the front inner periphery of the skin plate 20 and formed in a cylindrical shape along the front inner peripheral surface of the rear skin plate 20, and a slide provided on the inner peripheral side of the slide frame 22 A propulsion seal 23 for sealing between the frame 22 and the existing segment 8 and a slide frame 2 provided on the outer peripheral side of the slide frame 22 It is constituted by a sliding seal 24 for sealing between the rear skin plate 20 and. By incorporating the seal portion 14 in the shield machine 1 in advance, the seals 21 and 23, which generally require high accuracy, can be conveyed to the removal shield assembly position without disassembling.

  The rear skin plate 20 is a component constituting the rear portion of the skin plate 47 of the removal shield 13, that is, the rear portion of the outer peripheral wall portion of the outer peripheral frame 15, and an outer taper 25 is provided on the outer periphery of the rear end portion for releasing the backfill material. And an inner taper 26 for overcoming the step 49 between the segments 8 on the inner periphery of the rear end.

  The stop seal 21 and the propulsion seal 23 are a cylindrical seal sheet 27 attached to the inner peripheral surface of the base material 20, 22 made of the rear skin plate 20 or the slide frame 22, and a cylindrical shape along the inner peripheral surface of the seal sheet 27. And a seal plate 28 which is formed so as to be capable of expanding and contracting in the axial direction at the center in the axial direction and is fixed to the base materials 20 and 22 through the seal sheet 27 at both ends in the axial direction. It consists of a pressure seal. A pressurization device (not shown) is connected to the stop seal 21 and the propulsion seal 23 for filling and pressurizing a fluid such as water, air or oil between the seal plate 28 and the seal sheet 27, respectively. The stop seal 21 and the propelling seal 23 are swelled radially inward by being pressurized by a pressurizing device, and are contracted radially outward by being depressurized. When the stop seal 21 and the propulsion seal 23 are pressurized and bulge radially inward, the stop seal 21 and the propulsion seal 23 are pressed against the existing segment 8 to seal between the existing segment 8 and the base materials 20 and 22, and when the pressure is reduced, the diameter is reduced. It degenerates outward in the direction and is completely separated from the existing segment 8. Since the stop seal 21 and the propulsion seal 23 are constituted by such pressure seals, the seal portion 14 can be formed sufficiently thin in the radial direction, the skin plate 47 can be made thin, and the gap between the existing segment 8 and the natural ground 18 can be reduced. 19 can easily penetrate the skin plate 47.

  As shown in FIG. 4G and FIG. 9, the divided blocks 29, 30, 31, and 32 are obtained by dividing the front part of the outer peripheral frame 15 in the circumferential direction, and are segmented when the outer peripheral frame 15 is assembled. 8 is carried into the shield machine 1 together. Specifically, the divided blocks 29, 30, 31, and 32 are formed by dividing the front portion of the outer peripheral frame 15 into four parts in the vertical and horizontal directions, and are assembled by the erector 10 of the shield machine 1. The upper divided block 32 located at the upper part is formed in a key shape that can be inserted between the left and right divided blocks 30 and 31 from the inside in the radial direction. After the other three divided blocks 29, 30, and 31 are assembled, Can be assembled.

  The divided blocks 29, 30, 31, and 32 are each formed in an arc shape and a front divided plate 33 that is abutted against the rear skin plate 20, a support frame 34 that is provided on the inner peripheral side of the front divided plate 33, and A face holding jack 35 is provided on the support frame 34 to abut the front end of the existing segment 8 and hold the face. The front division plate 33 is a component that constitutes the front portion of the skin plate 47 of the removal shield 13. When the division blocks 29, 30, 31, and 32 are assembled to the front end portion of the seal portion 14, liquid is applied to the rear skin plate 20. Closely welded. That is, by welding the front divided plate 33 of each divided block 29, 30, 31, 32 to the rear skin plate 20, a cylindrical skin composed of the rear skin plate 20 and each front divided plate 33. The plate 47 is completed. The support frame 34 has an attachment surface 48 for attaching the partition wall 16 in a liquid-tight manner at the front end. The mounting surface 48 is formed so as to be all flush when the divided blocks 29, 30, 31, 32 are assembled in an annular shape, and is adapted to press the partition 16 receiving pressure from the front. As shown in FIG. 10, the face holding jack 35 is divided into a plurality of equally spaced blocks 29, 30, 31, 32 in the circumferential direction when the divided blocks 29, 30, 31, 32 are assembled in an annular shape. Two are arranged in 32. Thereby, when the face holding jack 35 abutted on the segment 8 to be disassembled is separated from the segment 8, the pressure of the backfilling material in the backfill space 43 can be held by the other face holding jack 35. ing. Each face holding jack 35 is provided with a shoe 12 that is in contact with the front end of the existing segment 8, and is in contact with the existing segment 8 evenly over a wide area.

  Next, a method for removing the tunnel using the removal shield 13 will be described.

  The start position of the shield machine 1 is separated from the starting point of the tunnel to be constructed, and after the shield machine 1 is dug from the start position to a predetermined arrival position to complete the tunnel, the start position When it is desired to remove the tunnel in the section from the starting point to the starting point, first, the shield machine 1 is advanced from the starting position to the starting point. At this time, the shield machine 1 excavates by taking a propulsion reaction force from the assembled temporary segment 8 while assembling the temporary segment 8 having a smaller diameter than the seal portion 14 at a position radially inward of the seal portion 14. Further, during excavation, a backfill material is injected into the gap 19 formed between the existing segment 8 and the natural ground 18 to fill the gap 19. As the backfill material, a gel-like material that is not solidified and is not absorbed by the natural ground 18 is used so that when the existing segment 8 is disassembled by the removal shield 13, the progress of the removal shield 13 is not hindered. For example, a water-absorbing polymer can be used as the gel material.

  As shown in FIG. 1B, when the shield machine 1 reaches the starting point, the stop seal 21 of the seal portion 14 is pressurized to press the stop seal 21 against the existing segment 8, and from the shield frame 2 to the seal portion 14. And the shield machine 1 is further dug. As a result, the seal portion 14 is left on the outer peripheral side of the temporary segment 8. When the erector 10 of the shield machine 1 is moved forward from the seal part 14, the shield machine 1 stops digging, the temporary segment 8 assembled along the inner periphery of the rear end of the seal part 14 is removed, and the seal part 14 is removed. Is exposed in the shield machine 1.

  As shown in FIG. 2 (c), the divided blocks 29, 30, 31, and 32 are carried into the shield machine 1, and a seal jack 36 for driving the slide frame 22 of the seal portion 14 is carried into the shield machine 1. Using the erector 10 of the excavator 1, the divided blocks 29, 30, 31, and 32 are sequentially attached to the front end portion of the seal portion 14 in an annular shape. As a result, the face holding jacks 35 of the divided blocks 29, 30, 31, 32 are arranged facing the front end of the existing segment 8. In addition, one end of the sealing jack 36 is attached to the divided blocks 29, 30, 31, and 32, and the other end of the sealing jack 36 is attached to the slide frame 22, and the slide frame 22 is driven in the axial direction by expansion and contraction of the sealing jack 36. It can be so. The sealing jack 36 and the face holding jack 35 are provided with stroke sensors 37 and 38 for detecting the lengths of the jacks 35 and 36, respectively. Further, as shown in FIG. 9, the sealing jacks 36 are provided on the divided blocks 29, 30, 31, 32, which are assembled in an annular shape, at a plurality of equal intervals in the circumferential direction, and the same hydraulic pressure supply pipe ( (Not shown) so that a plurality of positions in the circumferential direction of the slide frame 22 can be evenly pressed or pulled.

  Thereafter, as shown in FIG. 2 (d), the face holding jack 35 is extended to a position where it hits the existing segment 8 to fix the length, and the shield jack 11 is moved radially outward, and the divided block 29, Segments 9 and 39 having a radius larger than that of the temporary segment 8 are sequentially assembled in front of 30, 31, and 32, and the shield machine 1 is dug. At this time, a connection segment 39 for connecting the removal shield 13 and a main segment 9 to be described later is assembled in front of the divided blocks 29, 30, 31, 32, and a ring plate-shaped mounting plate is connected in front of the connection segment 39. 40 is attached. As shown in FIG. 4 (g), the mounting plate 40 is for supporting the partition plate 42 when the rear end of the main tunnel 41 constructed forward is covered with the partition plate 42, and the shield machine 1 During the construction of the tunnel 41 by digging up, a segment transport facility (not shown) such as a rail is inserted.

  As shown in FIGS. 3 (e) and 3 (f), in front of the mounting plate 40, the segment 9 for constructing the permanent tunnel 41 for permanent use is sequentially assembled and the shield machine 1 is dug. This tunnel 41 is completed. Since this segment 9 is formed with a larger radius than the temporary segment 8, the gap 19 formed on the outer peripheral side of this segment 9 can be minimized, and the amount of backfilling material used can be minimized. it can.

  When the main tunnel 41 is completed in this manner, the segment transportation equipment is removed, and as shown in FIG. 4G, a partition plate 42 is attached to the mounting plate 40 to close the rear end of the main tunnel 41, and is assembled in an annular shape. The partition block 29, 30, 31, 32 is provided with a partition wall 16 that closes the central opening thereof, and the backfilling space 43 formed between the partition wall 16 and the partition plate 42 is filled with mortar or earth and sand. The partition wall 16 is provided with a soil pressure gauge 45 for detecting the pressure of the backfill material, and the segment blocks 29, 30, 31, and 32 are provided with the segment disassembly erector 17 and removed. The shield 13 is completed. Further, the fixing of the removal shield 13 and the connection segment 39 is also released. Furthermore, the stroke sensors 37 and 38 and the earth pressure gauge 45 are connected to the control device 46. The control device 46 controls the face holding jack 35 and the sealing jack 36 according to signals input from the stroke sensors 37 and 38 and the earth pressure gauge 45, and pressurizes the propelling seal 23 and the stop seal 21 at a predetermined timing. Or it is programmed to depressurize. The predetermined timing is a timing at which the stop seal 21 and the propulsion seal 23 are switched when the removal shield 13 is propelled, and details will be described later.

  Thereafter, as shown in FIG. 4 (h), the face retaining jack 35 at the position where the existing segment 8 is disassembled is sequentially extended while the existing segment 8 is disassembled sequentially by the segment disassembling erector 17. When all the face holding jacks 35 have been extended by one segment or more rings, as shown in FIG. 5I, the backfilling space 43 is filled with the backfilling material and pressurized. The pressure of the backfilling material acts as a back pressure on the partition wall 16 and serves as a driving force for the removal shield 13. Further, after pressurizing the propelling seal 23 to press against the existing segment 8, the stop seal 21 is depressurized and separated from the existing segment 8, and when the removal shield 13 is propelled, the stop seal 21 is not rubbed against the existing segment 8. Do it.

  As shown in FIG. 5 (j), the control device 46 detects the pressure with the earth pressure gauge 45 while filling the backfilling space 43 with the backfilling material, and when the pressure reaches a predetermined pressure that the removal shield 13 can propel. The face holding jack 35 is retracted so as to maintain the pressure, and the removal shield 13 is pushed backward. At this time, the control device 46 retracts the sealing jack 36 according to the contraction of the face holding jack 35 so that the propulsion seal 23 does not move with respect to the existing segment 8. Specifically, the lengths of the face holding jack 35 and the sealing jack 36 are continuously detected by the stroke sensors 37 and 38, and the sealing jack 36 is retracted at the same speed as the face holding jack 35. The hydraulic pressure supplied to the jack 36 is controlled. When the face holding jack 35 is retracted by a length equal to or longer than one ring of the existing segment, the control device 46 stops the propulsion of the removal shield 13 and switches the seal to be used from the propulsion seal 23 to the stop seal 21. Start dismantling. The propulsion stop of the removal shield 13 is performed by stopping the filling of the backfill material. Further, the switching of the seal is performed by pressurizing the stop seal 21 so as to be brought into pressure contact with the existing segment 8 and then reducing the pressure of the propulsion seal 23 so as to be separated from the existing segment 8. Thereby, even if the existing segment 8 facing the propulsion seal 23 is disassembled, the seal can be maintained by the stop seal 21. In disassembling the existing segment 8, first, the face holding jack 35 abutting on the existing segment 8, which is a key segment, is retracted, and the key segment is gripped by the elector 17 and disassembled. Thereafter, the face holding jack 35 retracted from the key segment is extended and brought into contact with the existing segment 8 on the rear stage side. Thereafter, the other segments 8 adjacent to the disassembled segment 8 are sequentially disassembled in the same manner as described above. To do. At this time, the two face holding jacks 35 are sequentially withdrawn from the existing segment 8, but the pressure of the backfill material in the backfill space 43 is held by the other six face holding jacks 35. Can do. The number of face holding jacks 35 is not limited to eight. It is sufficient that at least four face holding jacks 35 are arranged at equal intervals in the circumferential direction of the skin plate 47. Even if one face holding jack 35 is separated from the existing segment 8, the pressure of the backfilling material can be held by the other three or more face holding jacks 35.

  When the existing segment 8 for one ring is disassembled as shown in FIG. 6 (k), the seal to be used again is switched from the stop seal 21 to the propulsion seal 23, and as shown in FIG. That is, after the removal shield 13 is propelled for a predetermined distance, the seal is switched, the segment is disassembled by one ring, the face holding jack 35 is extended, the seal is switched, and the removal shield 13 is propelled repeatedly. Remove existing segment 8.

  As described above, the cylindrical skin plate 47 that penetrates into the gap 19, the seals 21 and 23 that stop water between the skin plate 47 and the existing segment 8, and the skin plate 49 that is provided via the support frame 34. A face holding jack 35 that is in contact with the front end of the segment 8, a partition wall 16 that closes the central opening opposite to the penetration direction of the skin plate 47, and a backfill space 43 that is provided in the partition wall 16 and is in front of the partition wall 16. The nozzle 44 for filling the backfill material into the earth, the earth pressure gauge 45 for detecting the pressure of the backfill material filled from the nozzle 44 into the backfill space portion 43, and the backfill space portion 43 from the nozzle 44 are filled. A control device 46 for filling the return material and retracting the face holding jack 35 so that the pressure detected by the earth pressure gauge 45 becomes a predetermined pressure set in advance; Since the removal shield 13 is provided with the erector 17 for disassembling the existing segment 8 provided in the plate 47, the backfill space 43 can be prevented from being expanded in diameter, and the cutter and soil removal equipment can be prevented. Can be removed easily, and the tunnel constructed using a non-hardened gel-like material can be removed easily and inexpensively. Further, the length of the removal shield 13 can be kept short, and it is possible to easily cope with a curve.

  Further, since at least four face holding jacks 35 are arranged at equal intervals in the circumferential direction of the skin plate 47, the pressure of the backfilling material in the backfilling space 43 is filled with three or more face holding jacks 35. Can be held stably, and the existing segment 8 can be stably disassembled.

  When disassembling the existing segment 8, the backfilling space 43 is filled with the backfilling material from the nozzle 44, and the earth pressure gauge 45 detects the pressure of the backfilling material 43 in the backfilling space 43, and this pressure is preset. When the pressure reaches the predetermined pressure, the face holding jack 35 is retracted so as to maintain the pressure and the removal shield 13 is pushed, and the existing segment is held by the elector 17 while holding the pressure acting on the partition wall 16 with the face holding jack 35. Since 8 is sequentially disassembled, the tunnel can be easily backfilled with the removal shield 13 having a simple structure.

  In addition, although the shield machine 1 and the seal | sticker part 14 demonstrated what was formed in the cylindrical shape of a cross section, it does not restrict to this. It may be a cylinder with a rectangular cross section or a cylinder with another cross section. That is, the term “cylindrical shape” as used in this embodiment includes not only a circular cross-sectional shape but also other cross-sectional shapes.

  In addition, the divided blocks 29, 30, 31, and 32 are formed by dividing the front portion of the outer peripheral frame 15 into four parts in the vertical and horizontal directions, but are not limited to four. As long as it can be carried into the shield machine 1 and can be assembled by the erector 10, it may be divided into two or more.

  Further, the divided blocks 29, 30, 31, and 32 are assumed to be transported into the shield machine 1 together with the segment 8 after starting the shield machine 1. It is good also as what is built in. In this case, the divided blocks 29, 30, 31, and 32 and the seal portion 14 may be integrally formed in advance. However, since the length of the shield machine 1 is increased, it is preferable to use it for construction where the start shaft is sufficiently large and the ease of curve construction is not required.

  In addition, the case where the shield tunneling machine 1 is dug to complete the tunnel and then a part of the tunnel is removed by the removal shield 13 has been described. The removal shield 13 is a gel-like material that does not harden as a backfill material. It is also possible to remove the entire section if it is a tunnel using. In this case, the skin plate 47 of the removal shield 13 is inserted into the outer periphery of the end of the constructed tunnel, and the space opposite to the penetration direction of the partition wall 16 is sealed to fill the backfill material. The return space 43 may be formed.

(A) is a side view of a shield machine showing a preferred embodiment of the present invention, (b) is a side view of a main part of a shield machine that excavates by leaving the seal part of the removal shield on the outer peripheral side of the existing segment. FIG. (C) is a side view of a state in which a divided block is assembled to the seal part and an outer peripheral frame of the removal shield is formed at the front position of the existing segment, and (d) is a further assembly by assembling the segment at the front position of the outer peripheral frame. It is a principal part side view of a shield machine. (E) is the principal part side view of the shield machine which excavated from the state of FIG.2 (d), (f) is the principal part side view of the shield machine which further excavated from the state of (e). (G) is the side view of the removal shield completed in the front position of the existing segment, (h) is the side view of the removal shield which disassembled the existing segment for 1 ring. (I) is a side view of the removal shield in which the backfilling space in front of the partition wall is filled with the backfilling material, and (j) is a side view of the removal shield propelled by the filling pressure of the backfilling material. (K) is the side view of the removal shield which disassembled the existing segment for 1 ring from the state of FIG.5 (j), (l) is the removal shield which moved the propulsion seal back from the state of (k). It is a side view. It is a principal part enlarged view of FIG. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. FIG. 5 is a cross-sectional view taken along line B-B in FIG. 4. It is CC sectional view taken on the line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shield machine 8 Segment 9 Segment 13 Removal shield 16 Bulkhead 17 Electa 18 Ground 19 Gap 21 Stop seal (seal)
23 Propulsion seal (seal)
34 Support frame 35 Face holding jack 43 Backfill space 44 Nozzle 45 Earth pressure gauge 46 Controller 47 Skin plate

Claims (4)

  It is a removal shield that removes the tunnel built by backing up the gel-like backfill material that does not solidify in the gap between the assembled segment and the ground, while digging the shield machine while assembling the segments in the shield machine. A cylindrical skin plate that penetrates into the gap, a seal that stops water between the skin plate and the existing segment, and abuts against the front end of the existing segment that is provided on the skin plate via a support frame A face holding jack, a partition wall that closes a central opening opposite to the penetration direction of the skin plate, a nozzle that is provided in the partition wall, and that is used to fill a backfill material in a backfilling space in front of the partition wall; Earth pressure gauge for detecting the pressure of the backfill material filled in the backfill space from the nozzle, and from the nozzle to the backfill space A control device for filling the return material and retracting the face holding jack so that the pressure detected by the earth pressure gauge becomes a predetermined pressure set in advance, and for disassembling the existing segment provided in the skin plate A removal shield characterized by having an erector.   The removal shield according to claim 1, wherein at least four face holding jacks are arranged at equal intervals in the circumferential direction of the skin plate. In the tunnel removal method, the shield machine is excavated while assembling the segments in the shield machine, and the tunnel constructed by backing the gel-like backfill material that does not solidify in the gap between the assembled segment and the ground is removed. There,
A cylindrical skin plate is inserted into the gap, and a seal is provided to stop water between the skin plate and the existing segment, and a face holding jack that contacts the front end of the existing segment is attached to the skin plate via a support frame. The central opening opposite to the penetration direction of the skin plate is closed with a partition wall, and a nozzle for filling the backfilling space in the backfill space in front of the partition wall is provided in the partition wall, A earth pressure gauge for detecting the pressure of the backfill material filled in the backfill space is provided, and an erector for disassembling the existing segment is provided in the skin plate to constitute a removal shield,
The backfill material is filled from the nozzle into the backfill space and the pressure of the backfill material in the backfill space is detected by the earth pressure gauge, and when this pressure reaches a predetermined pressure, the pressure is The tunnel removal method, wherein the face holding jack is retracted to maintain the propulsion shield, and the existing segments are sequentially disassembled by the erector while maintaining the pressure acting on the partition wall by the face holding jack. . At least four face holding jacks are arranged at equal intervals in the circumferential direction of the skin plate, and when the face holding jack abutting on the segment to be disassembled is separated from the segment, the other three or more face holding jacks are held. The tunnel removal method according to claim 3, wherein the pressure of the backfilling material in the backfilling space can be maintained with a jack.

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