Soft and hard interbedding rockburst tunnel TBM (Tunnel Boring Machine) jamming escape construction method

Abstract

The invention discloses a soft and hard interbedded rockburst tunnel TBM jamming escape construction method. The method comprises the steps that rock ballast in a TBM cutter bin and in front of a tunnel face is cleaned; extrusion surrounding rock around a TBM shield is subjected to expanding excavation treatment, and a supporting structure is constructed above the shield; advanced small guide pipe construction is conducted on surrounding rock in front of the cutterhead; the collapse bodies around the cutter bin and the shield are cleared again, trial tunneling is carried out, if the collapse bodies cannot escape, the rock blocks are cleared again, and if the collapse bodies escape smoothly, the next operation is carried out; the TBM performs normal tunneling, and supports the machine clamping section to ensure the stability of the surrounding rock; and after the TBM smoothly passes through the machine clamping section, fiber concrete is used for backfilling the collapsed cavity. When the TBM is stuck due to rock burst, extrusion, collapse and the like of the tunnel, the methods of dangerous rock cleaning, pilot tunnel excavation, advance support, collapse section reinforcement and the like are adopted, so that the safety of constructors and TBM equipment can be effectively ensured, quick escape is realized, the influence on the construction period is reduced, and the economic loss caused by rock burst is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering, and in particular to a construction method for escaping a TBM stuck in a soft-hard interlayer rock burst tunnel. Background Art

[0002] Rockburst is a dynamic phenomenon in which the elastic deformation energy accumulated in the rock mass of underground engineering is suddenly released under excavation or other external disturbances, resulting in the explosion and ejection of surrounding rock. It seriously threatens the safety of underground engineering structures, equipment, property and personnel, hinders the progress of the project, and becomes a bottleneck problem restricting the development of deep underground engineering.

[0003] Due to the suddenness and destructiveness of rockbursts, the use of tunnel boring machines (TBMs) in tunnel construction in high-stress areas can effectively reduce construction risks and ensure the safety of personnel and equipment. TBM shields are usually made of steel and can be several centimeters thick. The shield body and the support structure behind the shield are directly connected, and personnel and equipment will not be directly exposed to the excavated rock wall. Therefore, when a rockburst occurs, whether it is rock spalling or explosive ejection, the shield body plays a certain protective role and can provide good protection for the construction personnel and mechanical equipment inside. However, when a large-scale rockburst occurs in a tunnel, the collapsed surrounding rock may cause the TBM shield to be stuck and the TBM cannot be excavated normally. If appropriate measures are not taken to get out of trouble in time, it will not only extend the construction period, but also bury the construction equipment in the tunnel and make it impossible to remove it, causing huge economic losses.

[0004] At present, among the research reports on the rescue of stuck machines in TBM tunnel construction, the invention patent with publication number CN105781562A discloses a "method for the rescue of stuck machines during tunnel boring machine construction". Although this technology can rescue the tunnel boring machine, it abandons the side panels of the cutterhead and the outer shield, resulting in large losses and cumbersome procedures; the invention patent with publication number CN106522963A discloses a "method for the rescue of stuck machines in TBM tunnel construction". This technology is suitable for the rescue of stuck machines in soft rock excavation, but is not applicable to hard rock excavation under high ground stress conditions, especially rock burst conditions; the invention patent with publication number CN106522963A discloses a "method for the rescue of stuck machines in TBM tunnel construction". This technology is suitable for the rescue of stuck machines in soft rock excavation, but is not applicable to hard rock excavation under high ground stress conditions, especially rock burst conditions; The invention patent 110469340A discloses "a construction method for getting a double-shield TBM stuck in a rockburst tunnel". This technology mainly targets situations where TBMs are stuck due to surrounding rock ejection, extrusion, landslides, etc., including TBM equipment protection, dangerous rock cleaning, slag removal and landslide section processing. It is suitable for getting a double-shield TBM stuck in hard rock excavation. TBMs stuck due to rockbursts under soft-hard interlayer conditions usually have large-scale soft rock deformation in the soft rock strata near the soft-hard boundary. If not handled properly, it can easily cause secondary disasters.

[0005] Deep tunnels in mountainous canyon areas have complex geological conditions and stress states, which are often accompanied by rock bursts of varying degrees. Rock bursts can cause the elastic strain energy stored in the surrounding rock to be suddenly released, resulting in destructive phenomena such as bursting, loosening, spalling, ejection, and even throwing.

[0006] At present, there is a lack of mature and effective experience at home and abroad on how to free TBMs from jams in high-ground stress rockburst tunnels, especially in areas with interbedded soft and hard layers. Summary of the invention

[0007] In view of the above problems, a construction method for escaping a TBM stuck in a rockburst tunnel with soft and hard interlayers is provided to effectively solve the problem of TBM stuck in a rockburst tunnel section with soft and hard interlayers.

[0008] The specific technical solutions are as follows:

[0009] A construction method for escaping a TBM stuck in a soft-hard interbedded rock burst tunnel, comprising:

[0010] Clean the slag inside the TBM cutter chamber and in front of the face;

[0011] The squeezed surrounding rock around the TBM shield is expanded and a support structure is constructed above the shield to ensure the safety of the expansion operation space;

[0012] Grouting reinforcement is performed on the soft rock in front of and above the cutterhead and the surrounding rock of the nearby face to prevent further collapse;

[0013] Conduct advance small pipe construction on the surrounding rock in front of the cutterhead to ensure that the surrounding rock will not collapse after normal excavation, and that the soft rock formation at the junction of soft and hard formations will not deform or collapse on a large scale;

[0014] Clear the collapsed body around the cutter chamber and shield again, and conduct trial excavation. If it is impossible to get out of the predicament, clear the rock again. If it is successful, proceed to the next step.

[0015] The TBM excavated normally and supported the stuck section to ensure the stability of the surrounding rock;

[0016] After the TBM successfully passed the stuck section, the collapsed cavity was backfilled with fiber concrete.

[0017] Specifically, when larger rock blocks in the cutter disc cannot be transported out of the cutter disc hole, the rocks are broken manually by using a handheld pneumatic pick, and the slag is shoveled into a woven bag and then poured into a belt conveyor, which transports it out of the cave.

[0018] Specifically, before entering the shield excavation construction area, construction personnel first conduct a surrounding rock hazard inspection to ensure that the support is firm and there is no dangerous rock falling; the excavation range is a top arch of 115-125°, a height of not less than 0.5 meters, and a length up to the heading face; during the excavation process, a steel arch frame welded and fixed to the shield is used as a supporting structure, and the top of the steel arch frame is densely packed with steel bars to block slag.

[0019] Specifically, in order to protect the cutter disc and prevent landslides caused by the cleaning of slag in front of the cutter disc in the later stage, glass fiber anchor rods are used to grout and reinforce the front of the cutter disc and its contour line, and the steel arch frame supported above and behind the shield is sealed with advance sprayed concrete, and then self-propelled hollow grouting anchor rods are laid for reinforcement.

[0020] Specifically, after the excavation above the shield is completed, the outer steel arch frame of the shield is removed ring by ring from the face of the shield to the tail of the shield, and the welding positions on the shield are polished and smooth; the accumulated slag in the L1 area of ​​the TBM equipment is cleaned up, and the cutter disc is retracted. The cutter disc is retracted to an appropriate position and the excavation cutter is installed for excavation. During the retracting process of the cutter disc, the main machine posture is high at the front and low at the back, and the TBM posture is adjusted to repeatedly advance and retreat to expand the hole diameter.

[0021] Specifically, the principles of "first down and then up" and "skip-hole grouting" should be followed during grouting reinforcement; when chemical grouting is carried out on the face, a special person should be arranged to pay attention to the leakage in the cutter head, and the leakage should be sealed in time if it is found. When the leakage is serious and cannot be sealed, grouting of the hole should be stopped.

[0022] Specifically, the construction method of the advance small duct is: the advance small duct is laid out in a plum blossom shape at the top arch of the rear part of the shield at 170-180 degrees, the water volume of the anchor drilling hole is strictly controlled during construction, the anchor construction is carried out in two sequences, chemical grouting is carried out after the anchor construction is completed, and the second sequence hole is constructed after the drilling and grouting of the first sequence hole of the anchor is completed, and the anchor is sealed with an anchor agent in time after the anchor is laid.

[0023] Specifically, during the trial excavation, ensure the cutter head speed is low and advance slowly to make the cutter head contact with the tunnel face. Observe the surrounding rock state at the shield and whether the excavation data is abnormal during the advancement process. During the trial excavation, push slowly and at a uniform speed to avoid the cutter head from getting stuck during the forward push.

[0024] Specifically, after the tail of the shield is exposed in the expanded tunnel section, support is carried out in time according to the design requirements, and nanofiber concrete is used for advance spraying to seal the exposed surrounding rock of the expanded tunnel section, and the backfill pipe reserved in the cavity position is backfilled with concrete of the same grade.

[0025] The beneficial effects of the above scheme are:

[0026] In the present invention, when the TBM is stuck due to surrounding rock ejection, extrusion, landslide, etc., methods such as clearing dangerous rocks around the TBM shield, excavating pilot tunnels, advanced support, and reinforcing the collapsed section are adopted, which effectively solves the problem of TBM cutterhead and shield being stuck due to large-scale ejection of surrounding rock under rock burst or wedge-shaped extrusion of structural belts in deep-buried soft and hard interlayer tunnels, thereby effectively ensuring the safety of personnel and equipment, quickly getting out of trouble, reducing the impact on the construction period, and reducing the economic losses caused by the jam. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow chart of the present invention;

[0028] Figure 2 is a cross-sectional view of a soft-hard interlayer tunnel in the present invention;

[0029] Figure 3 It is a schematic diagram of the construction support above the shield in the present invention;

[0030] Figure 4 It is a schematic diagram of grouting reinforcement around the cutterhead, the front of the palm face and the shield in the present invention;

[0031] In the attached figure: 1. TBM; 2. Hard rock; 3. Soft rock; 4. Curved beam; 5. Shield; 6. Channel steel; 7. Steel section; 8. Fiberglass anchor; 9. Advance small guide tube; 10. Hollow self-advancing anchor; 11. Anchor drilling rig; 12. Cutter head. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0035] An embodiment of the present invention provides a construction method for escaping a TBM stuck in a soft-hard interlayer rockburst tunnel, which includes:

[0036] S1, slag removal and cleaning: clean the rock blocks in the cutter chamber of TBM1; if the hard rock 2 in the soft and hard interlayer tunnel causes the cutter head 12 and the shield 5 to be stuck, the cutter must be removed first, and then the slag in the cutter chamber and in front of the face must be cleaned;

[0037] S2. Excavation and support of surrounding rock around shield 5: Excavate the squeezed surrounding rock around shield 5 in TBM1, and construct a support structure above shield 5 to ensure safety in the excavation operation space;

[0038] S3, landslide section reinforcement treatment: polyurethane grouting is used to reinforce the collapsed rocks in front of the cutter head 12 and near the shield 5 to prevent further landslide;

[0039] S4, advance small pipe construction: advance small pipe construction is carried out on the surrounding rock in front of the cutter head 12 to ensure that the surrounding rock will not collapse after normal excavation, and secondly to ensure that the soft rock formation at the junction of soft and hard formations will not deform or collapse on a large scale;

[0040] S5, clean up the collapsed body around the cutter chamber and the shield 5 again, and conduct trial excavation. If it is impossible to get out of trouble, clean up the rock again and expand and support the surrounding rock around the shield 5. If it is successfully out of trouble, proceed to the next step;

[0041] S6 and TBM1 are advancing normally and supporting the stuck section to ensure the stability of the surrounding rock;

[0042] S7, backfilling the collapsed cavity. After TBM1 successfully passed the stuck section, it backfilled the collapsed cavity with fiber concrete. During backfilling, the width of the anchor cavity matched the diameter of the hole for installing the sensor (in this case, the hole diameter was 65 mm and the width of the anchor cavity was 60 mm). When filling the anchor, the T-shaped surface of the T-bolt was not coated with anchor as much as possible to fit as closely as possible to the surrounding rock and better transmit the microseismic signal.

[0043] Specifically, when the larger rock blocks in the cutter disc 12 cannot be transported out of the cutter disc hole, the rock blocks are broken by hand-held pneumatic picks, and the slag is shoveled into woven bags and then poured into the 1# belt conveyor, which transports it out of the cave.

[0044] Specifically, before the construction personnel enter the expansion construction area, they should first conduct a surrounding rock risk inspection to ensure that the support is firm and there is no dangerous rock falling. The expansion range is a 120° top arch, 1 meter high (which can be adjusted appropriately according to the actual construction needs on site), and the length reaches the face; during the expansion process, HW125 steel 7 is used as support steel (the circumferential and longitudinal spacing of the steel 7 support is 1m), 10# channel steel 6 is used as crossbeam steel (the spacing of channel steel 6 does not exceed 0.5 meters) and welded to form a double M-shaped steel 7 arch frame as a support structure (the support structure can be welded to the shield 5), and H-shaped steel bars are densely arranged on the top of the steel arch frame to block slag. The support should be complete and qualified without damage. When the surrounding rock is poor, the support can be appropriately increased. After the foreman checks that it meets the support requirements, the expansion and slag removal can continue.

[0045] Specifically, in order to protect the cutter disc 12 and prevent the cutter disc 12 from collapsing again when the slag is cleaned in front of the cutter disc 12 in the later stage, a Φ32 glass fiber anchor rod 8 is used to grout and reinforce the front of the cutter disc 12 and its contour line. During the anchor rod construction, a YT-28 air gun steel drill is used to drill a hole. After drilling, the steel drill is pulled out, and then a glass fiber anchor rod 8 (the axial length of the anchor rod is 3m, and the effective length of the anchor rod is converted according to the space and angle in the cutter disc 12 during construction) is sent into the drill hole by an air gun. No hole is opened at the tail of the rod body for 1m, and the spacing between the remaining holes is 25cm. The layout position is determined according to the position of the cutter hole and the slag bucket in the cutter disc 12. After the layout is completed, the Φ32 glass fiber anchor rod 8 is used to advance the spraying of concrete to seal the steel arch frame supported above and behind the shield, and then the hollow self-propelled grouting anchor rod 10 is laid for reinforcement.

[0046] Specifically, after the excavation above the shield 5 is completed, the outer steel arch frame of the shield 5 is removed ring by ring from the face of the shield to the shield tail, and the welding position on the shield 5 is polished and smooth. During the dismantling process, a special person is arranged to observe the surrounding rock conditions above the shield 5. If any problems are found, the dismantling is stopped immediately and reinforcement is carried out; after that, the accumulated slag in the L1 area is cleaned up, and the cutter disc 12 is retracted. The cutter disc 12 is retracted to an appropriate position and three 20-inch excavation knives (diameter 10 cm) are installed for excavation. During the retracting process of the cutter disc 12, the main machine posture is high at the front and low at the back, and the posture of TBM1 is adjusted to repeatedly advance and retreat to expand the hole diameter.

[0047] Specifically, the principles of "first down and then up" and "skip hole grouting" are followed during grouting reinforcement; when chemical grouting is carried out on the face, a special person is arranged to pay attention to the leakage in the cutter head 12. Since it is impossible to spray concrete in the cutter head 12 to seal the face, if leakage is found, it is promptly sealed with geotextiles, slag bags, etc. When the leakage is serious and cannot be sealed, grouting of the hole is stopped.

[0048] Specifically, in order to construct the advance small guide tube 9 more efficiently, the vertical belt, advance drilling rig, construction platform and other facilities that have been installed in the L1 area of ​​the TBM1 equipment are removed before the anchor drilling rig 11 is installed, and the tail of the 1838 anchor drilling rig 11 is fixed to the arc beam 4 through a support plate and U-bolts, and the front is fixed to the large gear ring of the arch frame installer through a cantilever beam. Affected by the main beam and the tunnel support system, the installation angle of the drilling rig is 16-20°; when the drilling rig moves, the rear part detaches from the arc beam 4, and the cantilever beam is rotated through the large gear ring to drive the drilling rig to rotate, thereby achieving full coverage of the planned drilling positions.

[0049] Specifically, the construction method of the advance small conduit is as follows: a φ42 advance small conduit 9 is arranged in a plum blossom shape at the top arch of the tail of the shield 5 at 180° (a φ42 hollow self-propelled grouting anchor rod is selected, the anchor rod is 15m long, and the single section length is 1m), with a circumferential spacing of 35cm, a hole is opened on the anchor rod wall, and the longitudinal spacing of the holes is 25cm. One hole is opened in each section of the anchor rod, and the hole diameter is 8mm. No hole is set within 2m of the tail of the shield 5 (the specific length of the hole is determined according to the exposed length of the anchor rod on the upper part of the shield 5). During the construction, the amount of water in the anchor rod drilling hole is strictly controlled. The anchor rod construction is carried out in two sequences. Chemical grouting is carried out after the anchor rod construction is completed. After the drilling and grouting of the first sequence hole of the anchor rod is completed, the second sequence hole is constructed. The anchor rod should be constructed at a low speed to prevent the drill from getting stuck and the anchor rod from breaking. The anchor rod length is adjusted according to the drilling speed. After the anchor rod is laid, it is sealed with an anchoring agent in time, and the sealing length shall not be less than 50cm.

[0050] Specifically, during the trial excavation, ensure that the rotation speed of the cutterhead 12 is low, and advance slowly so that the cutterhead 12 contacts the face of the tunnel. Observe the surrounding rock state around the shield 5 and whether the excavation data during the advancement process is abnormal. During the trial excavation, push slowly and at a uniform speed. If the torque is large, reverse first, and when the rotation speed appears and the torque rises, stop reversing and continue to rotate forward; if the torque of the cutterhead 12 jumps greatly during the advancement process, or the torque continues to rise, find the position of the minimum torque of the cutterhead 12 by turning left and right, and try repeatedly; if the cutterhead 12 still cannot rotate, try to get out of trouble by retreating the cutterhead 12. During the retreat of the cutterhead 12, the main machine posture is high in front and low in the back. After the escape is successful, the rear legs are lifted when advancing forward, and the main machine is kept as horizontal as possible.

[0051] Specifically, during the trial excavation process, after the tail of shield 5 was exposed in the expanded tunnel section, support was carried out in a timely manner according to the design requirements, and C40 nanofiber concrete was used for advance spraying to seal the exposed surrounding rock of the expanded tunnel section. The backfill pipe reserved in the cavity position was backfilled with the same grade concrete or M20 mortar.

[0052] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A construction method for escaping a TBM stuck in a soft and hard interlayer rock burst tunnel, characterized in that: include: Clean the slag inside the TBM cutter chamber and in front of the face; The squeezed surrounding rock around the TBM shield is expanded and a support structure is constructed above the shield to ensure the safety of the expansion operation space; Grouting reinforcement is performed on the soft rock in front of and above the cutterhead and the surrounding rock of the nearby face to prevent further collapse; Conduct advance small pipe construction on the surrounding rock in front of the cutterhead to ensure that the surrounding rock will not collapse after normal excavation, and that the soft rock formation at the junction of soft and hard formations will not deform or collapse on a large scale; Clear the collapsed body around the cutter chamber and shield again, and conduct trial excavation. If it is impossible to get out of the predicament, clear the rock again. If it is successful, proceed to the next step. The TBM excavated normally and supported the stuck section to ensure the stability of the surrounding rock; After the TBM successfully passed the stuck section, the collapsed cavity was backfilled with fiber concrete.

2. The method for escaping a TBM stuck in a soft-hard interlayer rockburst tunnel according to claim 1 is characterized in that: When the larger rock blocks in the cutter disc cannot be transported out of the cutter disc hole, they are broken manually by hand-held pneumatic picks, and the slag is shoveled into woven bags and poured into belt conveyors, which transport it out of the cave.

3. The method for escaping a TBM stuck in a soft-hard interlayer rockburst tunnel according to claim 1 is characterized in that: Before entering the shield excavation construction area, construction personnel first conduct a surrounding rock hazard inspection to ensure that the support is firm and there is no dangerous rock falling; the excavation range is a top arch of 115-125°, a height of not less than 0.5 meters, and a length to the heading face; during the excavation process, a steel arch frame welded and fixed to the shield is used as a supporting structure, and the top of the steel arch frame is densely packed with steel bars to block slag.

4. The method for escaping a TBM stuck in a soft-hard interlayer rockburst tunnel according to claim 1 is characterized in that: In order to protect the cutter disc and prevent another landslide caused by the cleaning of slag in front of the cutter disc in the later stage, glass fiber anchor rods are used to grout and reinforce the front of the cutter disc and its contour line, and the steel arch frame supported above and behind the shield is sealed with advance sprayed concrete, and then self-propelled hollow grouting anchor rods are laid for reinforcement.

5. The method for escaping a TBM stuck in a soft-hard interlayer rockburst tunnel according to claim 1 or 3, characterized in that: After the excavation above the shield is completed, the outer steel arch frame of the shield is removed ring by ring from the face to the tail of the shield, and the welding position on the shield is polished and smooth; the accumulated slag in the L1 area of ​​the TBM equipment is cleaned up, and the cutter disc is retracted. The cutter disc is retracted to an appropriate position to install the excavation cutter for excavation. During the retracting process of the cutter disc, the main machine posture is high at the front and low at the back, and the TBM posture is adjusted to repeatedly advance and retreat to expand the hole diameter.

6. The method for escaping a TBM stuck in a soft-hard interlayer rockburst tunnel according to claim 1 or 5, characterized in that: When grouting reinforcement, follow the principles of "first down and then up" and "skip hole grouting". When chemical grouting is carried out on the face, arrange a special person to pay attention to the leakage in the cutter head. If leakage is found, it should be sealed in time. If the leakage is serious and cannot be sealed, stop grouting in the hole.

7. The method for escaping a TBM stuck in a soft-hard interlayer rockburst tunnel according to claim 1, characterized in that: The construction method of the advance small duct is: the advance small duct is laid out in a plum blossom shape at the top arch of the tail of the shield at 170-180°. The water volume of the anchor drilling hole is strictly controlled during construction. The anchor construction is carried out in two sequences. After the anchor construction is completed, chemical grouting is carried out. After the drilling and grouting of the first sequence hole of the anchor is completed, the second sequence hole is constructed. After the anchor is laid, it is sealed with an anchor agent in time.

8. The method for escaping a TBM stuck in a soft-hard interbedded rockburst tunnel according to claim 1, characterized in that: During the trial excavation, ensure the cutter head speed is low and advance slowly to make the cutter head contact with the tunnel face. Observe the surrounding rock state at the shield and whether the excavation data is abnormal during the advancement process. Push slowly and at a uniform speed during the trial excavation to avoid the cutter head from getting stuck during the forward push.

9. The method for escaping a TBM stuck in a soft-hard interbedded rockburst tunnel according to claim 1, characterized in that: After the tail of the shield is exposed in the expanded tunnel section, support is carried out in time according to the design requirements, and nanofiber concrete is used in advance spraying to seal the exposed surrounding rock of the expanded tunnel section. The backfill pipe reserved in the cavity position is backfilled with concrete of the same grade.

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