JP7397737B2 - Shield excavation method - Google Patents

Description

The present invention relates to a shield excavation method, and particularly to a shield excavation method that enables smooth excavation by a shield excavator.

The shield construction method excavates the ground with a cutter while pressing down the cut end of the shield machine with mud, muddy water, pressurized air, etc., and also places a tunnel lining body (segment ring) with segments behind the shield machine. This is a construction method in which a tunnel is formed underground from a starting shaft to a destination shaft while being assembled, and is widely used as a construction method for major tunnel construction in urban areas and plain areas.

The shield excavator used in the shield method is equipped with a rotary cutter for cutting the face surface on the front part of a metal shell called a skin plate, a bulkhead, a cutter drive device, an earth removal mechanism, etc. The system is equipped with a shield jack, an erector device, etc., and the erector device is used to assemble segment rings made of segments, and while the reaction force is taken from the tunnel lining by the assembled segment rings, the rotary cutter is moved together with the skin plate by the shield jack. By pushing it out, the tunnel is excavated while cutting the face.

In addition, a gap called tail clearance is maintained between the outer circumferential surface of the assembled segment ring and the inner circumferential surface of the skin plate at the rear end that covers it. When moving the excavator forward, the skin plate can be smoothly moved forward along the outer circumferential surface of the segment ring while leaving the segment ring in place. By utilizing the created gap, it becomes possible to advance the skin plate in a gradually bent direction with respect to the tunnel lining made of segment rings. Furthermore, in order to prevent earth and sand and groundwater from flowing into the shield excavator from the surrounding ground through the tail clearance, a tail seal member made of a flexible ring-shaped material is installed in the tail clearance, for example, in the segment segment. A plurality of rings are attached at intervals in the axial direction of the tunnel lining and skin plate, and the spaces between the plurality of attached tail seal members are filled with a tail sealer material such as a tail seal grease material. It is injected in the same way. This allows the tail seal member to slide smoothly along the outer circumferential surface of the segment ring, and the tail sealer material and the tail seal member work together to fill the gap caused by the tail clearance. It is possible to exhibit a strong water-stopping function that prevents groundwater and earth and sand from flowing into the inside of the skin plate (for example, see Patent Document 1).

JP2006-118239

However, as the tunnel excavation progresses, the tail sealer material injected into the gap between the tail seal members may lose its fluidity and deteriorate, or it may become stuck in the gap between the rear segment ring and the ground. When the cement in the grout material filled as a filling material is mixed in, the tail sealer material changes in quality and becomes hard, which may impede smooth excavation by the shield excavator.

In particular, in curved sections of shield tunnels, for example, to prevent interference between the installed segment ring and the skin plate of the shield tunneling machine, the segments constituting the segment ring should be thin and have a reduced diameter outer circumference. The outer circumferential surface of the reduced-diameter segment ring, which is used and therefore constitutes the curved portion of the shield tunnel, and the non-reduced-diameter segment ring, which is thicker than this and constitutes the straight portion of the shield tunnel. A step will be created between the outer peripheral surface and the outer circumferential surface. Therefore, at the inflection point part of the shield tunnel where the curved part transitions to the straight part, the tail seal member stands at a relatively steep slope with respect to the outer peripheral surface of the reduced diameter segment ring. from a state in which they are in contact with each other at a relatively gentle slope (see Fig. 3 (a)), to a state in which they ride on the outer peripheral surface of the non-reduced diameter segment ring and are in contact in a state in which they lie down at a relatively gentle slope (see Fig. 3 (e)). (see), the volume of the gap between adjacent tail seal members decreases, and this increases the pressure in the gap, making it easier for the shield excavator to dig even more smoothly. more likely to be inhibited.

Even if the tail sealer material injected into the space between adjacent tail seal members deteriorates or changes in quality and becomes hard as tunnel excavation progresses, the shield excavation machine can smoothly seal the tail sealer. To provide a shield excavation method capable of carrying out construction while ensuring that the excavation is not obstructed.

In the shield excavation method, the present invention uses a tail sealer material that is injected so as to fill the spaces between a plurality of tail seal members attached to the rear end portion of a skin plate at intervals in the axial direction. A predetermined segment ring is provided with a plurality of cleaning water supply and discharge holes at intervals in the direction, and the interval portion injected with the tail sealer material is arranged so that the predetermined segment ring is filled with the tail sealer material. After cleaning the gap by supplying and discharging the gap into which the tail sealer material is filled through the wash water supply and discharge hole while , the tail sealer material is reinjected into the spaced portion that has passed through the predetermined segment ring, and the excavation work is continued, and the tail sealing member is axially attached to the rear end portion of the skin plate. At least three bodies are attached at intervals, and the interval parts to be cleaned are formed in at least two places in the axial direction, and while one of the interval parts is being cleaned, the other interval parts are cleaned. To provide a shield excavation method in which cleaning is performed from the spaced part on the front side while maintaining the sealing function of the tail seal member and the tail sealer material in a state where the part is filled with the tail sealer material. Thus, the above objective was achieved.

In the shield excavation method of the present invention, the predetermined segment ring in which the plurality of wash water supply and discharge holes are provided at intervals in the circumferential direction is one of the plurality of segment rings arranged in series in the axial direction. It is a reduced diameter segment ring whose outer diameter is reduced due to its reduced thickness, which is connected to the rear end in the axial direction of a non-reduced segment ring whose outer diameter is not reduced. is preferred.

Further, in the shield excavation method of the present invention, the predetermined reduced diameter segment ring provided with the plurality of wash water supply and discharge holes is arranged in the axial direction of the non-reduced diameter segment ring that constitutes a straight portion of the shield tunnel. Preferably, it is a diameter-reduced segment ring at an inflection point portion, which is connected to the rear end of the shield tunnel and is disposed at the tip of the curved portion of the shield tunnel.

According to the shield excavation method of the present invention, even if the tail sealer material injected into the space between adjacent tail seal members deteriorates or changes in quality and becomes hard as tunnel excavation progresses, , it is possible to carry out construction while ensuring that the smooth excavation by the shield excavator is not obstructed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view illustrating the configuration of a shield excavation machine in which a shield excavation method according to a preferred embodiment of the present invention is implemented. FIG. 2 is an explanatory diagram of a sharply curved portion of a shield tunnel constructed using a shield excavation method according to a preferred embodiment of the present invention. (a) to (e) are explanatory diagrams of a shield excavation method according to a preferred embodiment of the present invention. (a) and (b) are explanatory diagrams of wash water supply and discharge holes provided in a diameter-reduced segment ring for carrying out a shield excavation method according to a preferred embodiment of the present invention.

As shown in FIG. 1, a shield excavation method according to a preferred embodiment of the present invention uses, for example, a mud pressure type shield excavation machine as the shield excavation machine 11, in which the outer shell of the shield excavation machine 11 is configured. A tail is held between the outer circumferential surface of segment rings 14a and 14b, which are tunnel lining bodies formed by assembling segments 13a and 13b, and the inner circumferential surface of skin plate 12 on the inner rear side of skin plate 12. A plurality of tail seal members 15 and an interval portion 15a between these tail seal members 15 are provided to prevent earth and sand and groundwater from flowing into the shield excavator 11 from the surrounding ground through the clearance 20. This method was adopted as an excavation method to allow the shield excavator 11 to carry out construction without interfering with the smooth excavation by the tail sealer material 16 injected into the shield excavator 11.

In addition, in the shield tunnel construction method of the present embodiment, especially in a shield tunnel 50 including a sharply curved portion 50a as shown in FIG. Since the assembled diameter-reduced segments 13b are used, which have a reduced outer diameter and a reduced width in the tunnel axis direction At the connecting inflection point portion 50c, there is a gap between the outer circumferential surface of the reduced diameter segment ring 14b of the sharply curved portion 50a and the outer circumferential surface of the non-reduced diameter segment ring 14a whose outer diameter is not reduced in the straight portion 50b. , a stepped portion 50d is generated (see FIGS. 3(a) to 3(e)). As the shield excavator 11 excavates, when a plurality of tail seal members 15 attached to the rear inside of the skin plate 12 ride on this stepped portion 50d, the interval portions 15a of the plurality of tail seal members 15 are removed. As the volume becomes smaller, the tail sealer material 16 injected into the interval portion 15a is pressurized, and smooth excavation by the shield excavator 11 is more likely to be inhibited. For this reason, in this embodiment, by employing the shield excavation method described later, the plurality of tail seal members 15 and the interval portion 15a of these tail seal members 15 are removed at such an inflection point portion 50c. The tail sealer material 16 injected into the tail sealer material 16 makes it possible to prevent smooth excavation by the shield excavator 11 from being hindered.

In the shield excavation method of this embodiment, as shown in FIGS. 3(a) to 3(e), a plurality of tails are attached to the rear end portion of the skin plate at intervals in the axial direction (tunnel axial direction) The tail sealer material 16 injected into the interval portion 15a of the sealing member 15 is transferred to a predetermined portion of the segment rings 14a, 14b in which a plurality of cleaning water supply and discharge holes 17 (see FIG. 4) are provided at intervals in the circumferential direction. Then, while the interval portion 15a in which the tail sealer material 16 is injected is arranged in the predetermined segment rings 14a and 14b, the tail sealer material 16 is injected into the wash water through the wash water supply/discharge hole 17. The tail sealer material 16' (FIGS. 3(d) and (e) (see) was re-injected and excavation work continued.

In addition, in this embodiment, the predetermined segment rings 14a, 14b provided with a plurality of cleaning water supply and discharge holes 17 at intervals in the circumferential direction are the same as those of the plurality of segment rings 14a, 14b arranged in series in the axial direction X. Among them, for example, a condensed segment ring 14a whose outer diameter has been reduced due to its reduced thickness is connected to the rear end of the non-reduced segment ring 14a in the axial direction X. It is a diameter segment ring 14b.

Furthermore, in this embodiment, the predetermined diameter-reduced segment ring 14b provided with the plurality of cleaning water supply and discharge holes 17 is a non-reduced-diameter segment ring that constitutes the straight portion 50b (see FIG. 2) of the shield tunnel 50. The diameter-reduced segment ring 14b has an inflection point portion 50c arranged at the tip of a curved portion (steep curved portion) 50a of the shield tunnel 50, which is connected to the rear end portion of the shield tunnel 14a in the axial direction X. (See Figures 3(a) to (e)).

In this embodiment, the shield excavator 11 is, for example, a mud pressure type shield excavator, and as shown in FIG. A rotary cutter 30 is provided at the tip of the skin plate 12, which is a cylindrical outer shell body. Inside the skin plate 12, a mud pressure chamber 32 partitioned by a partition wall 31, a cutter drive device 33, and a screw are provided. It is equipped with an earth removal mechanism 34 using a conveyor, a shield jack 35, an erector device 36 for segment assembly, and the like. Then, the shield excavator 11 uses the erector device 36 to assemble the segment rings 14a, 14b which will become the tunnel lining body using the segments 13a, 13b, and while taking the reaction force from the assembled segment rings 14a, 14b, the shield By pushing the rotary cutter 30 forward together with the skin plate 12 by the jack 35, the face surface is cut, and the cut earth and sand are discharged as mud through the earth removal mechanism 34, and the tunnel is excavated. ing.

In addition, in this embodiment, when the shield tunneling machine 11 is moved forward, the skin plate 12 smoothly moves along the outer peripheral surface of the segment rings 14a, 14b while leaving the assembled segment rings 14a, 14b in place. In order to be able to move forward in the axial direction A gap called a tail clearance 20 is maintained between the inner peripheral surface and the inner peripheral surface.

Furthermore, in this embodiment, the segment rings 14a and 14b, which serve as the tunnel lining of the shield tunnel 50, can be formed by assembling a plurality of known segments 13a and 13b that are arranged in a ring shape in the circumferential direction. can. The segments 13a constituting the non-reduced diameter segment ring 14a of the straight portion 50b of the shield tunnel 50 are made of steel or reinforced concrete and have a width of about 100 cm in the tunnel axis direction X of the shield tunnel 50 and a thickness of about 125 cm. The segment 13b constituting the diameter-reduced segment ring 14b of the straight portion 50b is made of a non-woven material having a width of about 30 cm in the tunnel axis direction X of the shield tunnel 50 and a thickness of about 100 cm. The segment is made of steel or reinforced concrete and is thinner than the segment 13a forming the reduced diameter segment ring 14a. These segments 13a and 13b are curved in an arc shape with the same radius of curvature, and are assembled to have an inner peripheral surface shape with a similar inner diameter, so that the outer peripheral surface of the assembled non-reduced diameter segment ring 14a and , and the outer circumferential surface of the diameter-reduced segment ring 14b, a stepped portion 50d having a height of, for example, about 25 cm is generated at these connecting portions (see FIGS. 3(a) to 3(e)). )reference).

Furthermore, in this embodiment, the tail seal member 15 attached to the rear end portion of the skin plate 12 is preferably made of a known wire brush seal, and the proximal end portion is attached to the inner peripheral surface of the rear end portion of the skin plate 12. With the tail seal members 15b fixed, they are attached continuously in an annular shape in the circumferential direction, and three pieces are attached at intervals in the axial direction Spacing portions 15a are formed at two locations in the axial direction. The tail seal member 15 made of a known wire brush seal is preferably impregnated with a sealant made of the same material as the tail sealer material 16 described below, for example, to improve the sealing function. The tail sealer material 16 is stretched inward from the inner surface of the skin plate 12 with a length larger than the maximum gap width of the tail clearance 20 between the skin plate 12 and the outer peripheral surfaces of the segment rings 14a and 14b. It is set up so that it comes out. As a result, the tail sealer material 16 maintains the state in which the inner tip portion is in contact with the outer circumferential surfaces of the segment rings 14a, 14b, and increases the tail clearance 20 between the skin plate 12 and the outer circumferential surfaces of the segment rings 14a, 14b. For example, the outer circumferential shape is in contact with the outer circumferential surface of the reduced-diameter segment ring 14b in a relatively steeply inclined state (see FIG. 3(a)). ), (b)) to a state in which it rides on the outer peripheral surface of the non-reduced diameter segment ring 14a and is in contact with it while lying at a relatively gentle slope (see FIG. 3(e)). It has become.

Further, in this embodiment, the tail sealer material 16 injected into the interval portion 15a of the three tail seal members 15 attached to the rear end portion of the skin plate 12 is, for example, a well-known sealing material having fluidity and viscosity. , preferably tail seal grease can be used. Tail sealer material 16, preferably tail seal grease, is applied to each adjacent tail seal member 15 using a known feeding device, preferably via a feed channel (not shown) provided along skin plate 12. It is injected so as to fill the space 15a between them.

In the shield excavation method of this embodiment, the tail sealer material 16 is injected into the two spaced parts 15a of the three tail seal members 15 attached to the rear end portion of the skin plate 12 of the shield excavator 11. In this state, at the rear of the skin plate 12, the segment rings 14a, 14b made up of the segments 13a, 13b are assembled using the erector device 36, and the shield is removed while taking reaction force from the tunnel lining body by the assembled segment rings 14a, 14b. By pushing the rotary cutter 30 forward together with the skin plate 12 by the jack 35, the shield tunnel 50 including the straight portion 50b and sharply curved portion 50a as shown in FIG. 2 is excavated while cutting the face surface. I can do it.

As the shield tunneling machine 11 continues to excavate, for example, the rear end portion of the skin plate 12 to which the tail seal member 15 is attached is at an inflection point portion 50c where the shield tunnel 50 transitions from the sharply curved portion 50a to the straight portion 50b. As shown in FIG. 3(a), the tail sealer material 16 When the spaced portion 15a injected with is placed over the reduced-diameter segment ring 14b at the terminal end, the reduced-diameter segment ring 14b at the terminal end is injected with a plurality of cleaning water at intervals in the circumferential direction. As a predetermined segment ring provided with a supply/discharge hole 17, cleaning water is supplied through the cleaning water supply/discharge hole 17 to the interval portion 15a into which the tail sealer material 16 is injected, and another cleaning water supply/discharge hole is provided. By discharging through 17, the tail sealer material 16 is washed away thereby cleaning the spaced portion 15a.

Here, a plurality of wash water supply and discharge holes 17 provided at intervals in the circumferential direction of the diameter-reduced segment ring 14b at the terminal end are connected to the skin plate 12 of the shield excavator 11, as shown in FIG. 4(a). After passing, the backing material 21 (see FIGS. 3(a) to 3(e)) is injected into the gap between the outer peripheral surface of the reduced diameter segment ring 14b left behind and the surrounding ground. The backfill injection hole 18a provided for this purpose can be used as is. Furthermore, as shown in FIG. 4(b), in addition to the backfilling injection hole 18a, a supply and discharge hole 18b for supplying and discharging cleaning water is separately formed, thereby making the supply and discharge of cleaning water even smoother. It becomes possible to do so. This makes it possible to improve the cleaning efficiency of the spaced portion 15a of the tail seal member 15.

In this embodiment, as described above, a predetermined segment ring in which a plurality of cleaning water supply and discharge holes 17 are provided at intervals in the circumferential direction is used, for example, at the end of the sharply curved portion 50a of the shield tunnel 50. In the diameter-reduced segment ring 14b, the interval portion 15a between adjacent tail seal members 15 is cleaned by the cleaning water, so that the tail injected into the interval portion 15a between the tail seal members 15 is Even if the sealer material 16 deteriorates or changes in quality and becomes hard as tunnel excavation progresses, and is in a state where smooth excavation by the shield excavator 11 is likely to be inhibited, such a state It becomes possible to improve this so that the shield excavator 11 can continue to perform smooth excavation.

In particular, in this embodiment, there is a gap between the outer circumferential surface of the reduced diameter segment ring 14b that constitutes the sharply curved portion 50a of the shield tunnel 50 and the outer circumferential surface of the non-reduced diameter segment ring 14a that constitutes the straight portion 50b. A stepped portion 50d occurs at the connecting portion of the tail seal member 15, and therefore, at the inflection point portion 50c of the shield tunnel 50 where the sharp curve portion 50a transitions to the straight portion 50b, the outer circumferential shape of the tail seal member 15 is reduced in diameter. From a state in which it is in contact with the outer circumferential surface of the reduced diameter segment ring 14b at a relatively steep slope (see FIG. 3(a)), it rides on the outer circumferential surface of the non-reduced diameter segment ring 14a and becomes relatively steep. By changing to the state in which they are in contact with each other while lying on a gentle slope (see FIG. 3(e)), the volume of the gap portion 15a between adjacent tail seal members 15 decreases, and as a result, the gap decreases. As the pressure in the portion 15a increases, smooth digging by the shield tunneling machine 11 is more likely to be hindered, but as described above, the cleaning water causes the gaps between the adjacent tail seal members 15 to be inhibited. By cleaning the spaced portion 15a, it is possible to improve such a condition so that the shield excavator 11 can continue to perform smooth excavation.

Further, in the present embodiment, after cleaning the interval portion 15a between adjacent tail seal members 15 as described above, preferably the cleaned interval portion 15a drains the cleaning water through the cleaning water supply and discharge hole 17. After passing through the predetermined reduced diameter segment ring 14b that has been fed and discharged, the cleaned spaced portion is fed using a known feed device, preferably via a feed channel (not shown) provided along the skin plate 12. It becomes possible to continue the excavation work by injecting the tail sealer material 16 again into the tail sealer 15a (see FIGS. 3(d) and (e)).

As a result, according to the shield excavation method of this embodiment, the tail sealer material 16 injected into the space 15a between adjacent tail seal members 15 will not deteriorate or change in quality as tunnel excavation progresses. This makes it possible to carry out construction while making improvements so that smooth excavation by the shield excavator is not hindered, even if the excavation becomes hard.

Furthermore, in the present embodiment, at least three tail seal members 15 are attached to the rear end portion of the skin plate 12 at intervals, so that the interval portions 15a to be cleaned are provided at at least two locations in the axial direction. While cleaning one gap part 15a, the other gap part 15a can be filled with the tail sealer material 16 (FIG. 3(b), (d)), each interval portion 15a can be cleaned while maintaining the sealing function of the tail seal member 15 and tail sealer material 16.

Note that the present invention is not limited to the above embodiments, and various changes can be made. For example, a predetermined segment ring for cleaning the space between adjacent tail seal members is connected to the rear end in the axial direction of a non-reduced diameter segment ring that constitutes a straight portion of the shield tunnel. , it does not necessarily have to be a diameter-reduced segment ring at the inflection point located at the tip of the curved portion of the shield tunnel. Further, the predetermined segment ring for cleaning the space between adjacent tail seal members does not necessarily have to be a reduced diameter segment ring whose outer diameter is reduced due to its reduced thickness. , it may be a non-reduced segment ring whose outer diameter is not reduced. Furthermore, the number of tail seal parts attached to the rear end portion of the skin plate at intervals does not necessarily need to be three, and may be four or more. Furthermore, the interval portions to be cleaned do not necessarily need to be formed at two locations, and may be formed at three or more locations.

11 Shield excavator 12 Skin plate 13a Non-reduced diameter segment 13b Reduced diameter segment 14a Non-reduced segment ring 14b Reduced diameter segment ring 15 Tail seal member 15a Interval portion 15b Base end portion 16, 16' Tail sealer material 17 Cleaning water supply and discharge Hole 18a Backfill injection hole 18b Supply/discharge hole 20 Tail clearance 21 Backfill material 50 Shield tunnel 50a Sharp curve section 50b Straight section 50c Inflection point section 50d Step section X Axial direction of skin plate (tunnel axial direction)

Claims (3)

In the shield excavation method, tail sealer material is injected and injected into the spaces between a plurality of tail seal members that are attached to the rear end of the skin plate at intervals in the axial direction. A predetermined segment ring is provided with a plurality of cleaning water supply and discharge holes, and an interval portion in which the tail sealer material is injected is arranged so that the predetermined segment ring is filled with the tail sealer material. , by supplying and discharging the cleaning water to the gap portion filled with the tail sealer material through the cleaning water supply and discharge hole, and then discharging the gap portion, and then cleaning the predetermined gap portion. The tail sealer material is re-injected into the space that passed through the segment ring, and the excavation work continues.
At least three tail seal members are attached to the rear end portion of the skin plate at intervals in the axial direction, and the interval portions to be cleaned are formed at at least two locations in the axial direction,
While cleaning one of the spaced parts, other spaced parts are filled with the tail sealer material while maintaining the sealing function of the tail seal member and the tail sealer material; A shield excavation method in which cleaning is performed from the spaced part on the front side . The predetermined segment ring in which a plurality of wash water supply and discharge holes are provided at intervals in the circumferential direction is a non-reduced segment ring whose outer diameter is not reduced among the plurality of segment rings arranged in succession in the axial direction. 2. The shield excavation method according to claim 1, wherein the diameter segment ring is a reduced diameter segment ring which is connected to the rear end in the axial direction of the diameter segment ring and whose outer diameter is reduced due to the reduced thickness. The predetermined diameter-reduced segment ring provided with the plurality of wash water supply and discharge holes is connected to an axial rear end portion of the non-diameter-reduced segment ring that constitutes a straight portion of the shield tunnel. 3. The shield excavation method according to claim 2, wherein the ring is a diameter-reduced segment ring at an inflection point located at the tip of a curved portion of the shield tunnel.