Tunnel soft rock section open-type TBM (Tunnel Boring Machine) de-trapping method

Abstract

The invention relates to the technical field of TBM tunnel construction, in particular to a tunnel soft rock section open type TBM detrapping method which comprises the following steps that S1, the vertical hole opening position and the hole opening size are determined; s2, grouting reinforcement is conducted on the area around the trepanning position, and then trepanning is conducted; s3, supporting the soil body around the opening; s4, continuing to construct the upper longitudinal guide; s5, constructing an upper transverse guide; s6, constructing a left side guide and a right side guide; and S7, the shield tunneling machine is started to continue working, and escaping is achieved. Deformed soil bodies on the upper portion, the side portions and the bottom of the shield tunneling machine can be cleaned, surrounding soil bodies can be reinforced and supported, the working resistance of a cutter head of the shield tunneling machine is reduced, and the cutter head can be restarted to get out of trouble.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of TBM tunnel construction, and particularly relates to a method for freeing an open TBM in a soft rock section of a tunnel. BACKGROUND

[0002] In recent years, open full-face tunnel boring machine (TBM) construction technology has made great progress, especially under the background of rapid infrastructure construction, technological innovation has significantly improved the efficiency of tunnel construction. As an advanced tunnel construction equipment, open TBM has unique advantages in hard rock tunnel and super-long distance tunnel projects due to its high construction efficiency, intelligent control and good operation safety.

[0003] However, in areas with active regional fault structures, complex soft geological conditions pose a serious challenge to construction safety. The broken zone, joint dense zone and unstable surrounding rock structure commonly found in such areas significantly reduce the self-stability of the rock mass. When the TBM advances to the fault fracture zone, the working face often collapses due to the instability of the surrounding rock, causing the cutterhead to be stuck or pieces to fall off, etc.

[0004] Specifically, in the fault fracture zone, the upper loose rock mass is prone to instability and peeling off and accumulating in the cutterhead area, which may cause the following hazards: (1) uneven force on the cutter, causing equipment operation to be blocked; (2) further instability of the surrounding rock near the working face, causing a collapse cavity; (3) destruction of the tunnel roof structure and even the formation of a cavity. This geological disaster not only increases the repair cost and construction difficulty, but also significantly reduces the TBM excavation rate, and poses a potential threat to the safety of workers.

[0005] There is a TBM freeing method that first excavates the tunnel surrounding rock behind the shield to form a work area and supports the tunnel surrounding rock in the work area with a support structure; then makes a lengthened grouting anchor pipe above the shield and cutterhead from the work area and grouts to reinforce the tunnel surrounding rock above the cutterhead and shield; then excavates a longitudinal pilot tunnel step by step and supports and reinforces it step by step, finally freeing the TBM. However, this method has many drawbacks: first, the TBM will support the tunnel surrounding rock behind it in time during its journey, and when the TBM is blocked, a ring-shaped excavation will be made behind the shield, which requires the removal of the support structure for excavation, significantly increasing the construction period. Moreover, the shield machine itself is in a fault fracture zone prone to collapse, and after the support is removed, a large-scale ring-shaped excavation is carried out, which is extremely likely to cause the shield tail to collapse again, thereby causing a major safety accident. Therefore, this TBM freeing method is contrary to the construction principle of "less excavation and quick support" in poor geological sections, and this TBM freeing method only exists in the theoretical stage, and the actual implementation will seriously affect the construction period and pose a great safety risk. This TBM freeing method cannot truly solve the problem of TBM travel obstruction.

[0006] Therefore, there is a need to design a construction method to solve the above technical problems. SUMMARY

[0007] The purpose of the present application is to provide an open type TBM escape method for tunnel soft rock section to solve the problems existing in the prior art, which can clean the deformed soil above, side and bottom of the shield machine, and also can reinforce and support the surrounding soil, so that the working resistance of the cutter head of the shield machine is reduced, and the shield machine can be started again to escape.

[0008] The present application provides an open type TBM escape method for tunnel soft rock section, comprising the following steps: S1. Determine the vertical hole position and hole size above the ring steel segment near the tail of the shield; S2. Grouting reinforcement is carried out on the area around the hole position, and after the reinforcement is completed, a first skylight is cut on the ring steel segment below the hole position, and the soil above the hole position is excavated from the first skylight, until the set hole size is reached; S3. Steel truss is arranged in the hole to support the surrounding soil; S4. Grouting reinforcement is carried out on the soil above the front of the steel truss, and after the reinforcement is completed, excavation is carried out towards the cutter head, and after a set distance is excavated, steel truss is arranged to support the surrounding soil; repeat this process until the frontmost steel truss reaches 1m~2m in front of the cutter head, and the upper longitudinal guide construction is completed; S5. Grouting reinforcement is carried out on the soil above the side of the upper longitudinal guide at the position of the collapsed cavity area, and after the reinforcement is completed, the cutter head is excavated laterally, and after a set distance is excavated, steel truss is arranged to support the surrounding soil, and this process is repeated until the length of the most lateral steel truss reaches the side of the cutter head, and the upper horizontal guide construction is completed; S6. Excavate from the tail of the shield on both sides to the front of the cutter head, and use the support body to support the surrounding soil to obtain the left guide and the right guide; S7. Start the shield machine to continue operation to realize escape.

[0009] As an embodiment, in S7, if the shield machine fails to start, excavate from the front end of the left guide and the right guide to the middle in the transverse direction, and use the support body to support the surrounding soil to obtain the lower horizontal guide, and then restart the shield machine to realize escape.

[0010] As an embodiment, the support body is a steel truss or a wooden frame, and the top of the wooden frame has double-layer bamboo plywood.

[0011] As an embodiment, in S2, the first grouting anchor and the second grouting anchor are respectively arranged from two positions behind the opening position, the length of the first grouting anchor is greater than the length of the second grouting anchor, and the inclination angle of the first grouting anchor and the second grouting anchor with the horizontal direction is 40°-50°.

[0012] As an embodiment, the first grouting anchor has 5 roots, the length of each first grouting anchor is 3.5m, and the lateral spacing between adjacent two first grouting anchors is 0.5m; the second grouting anchor has 5 roots, the length of each second grouting anchor is 2.1m, and the lateral spacing between adjacent two second grouting anchors is 0.5m.

[0013] As an embodiment, in S2, a second skylight is arranged on the ring steel pipe piece behind the opening position, and the staff stands behind the bottom of the second skylight and loosens and excavates the soil body of the opening position along the inclined direction.

[0014] As an embodiment, in S2, when the first skylight of the ring steel pipe piece below the opening position is constructed, the first skylight position of the ring steel pipe piece is first evenly divided into multiple small ring steel pipe pieces, each small ring steel pipe piece is cut, and then excavation is performed until the opening depth requirement is reached.

[0015] As an embodiment, before the small ring steel pipe piece is cut, the column is used as a support, after the small ring steel pipe piece is cut, the column is used to support the top of the hole after the opening depth requirement is reached, and the bottom of the column is fixed on the shield machine main beam.

[0016] As an embodiment, the top of the column in the steel truss has a cross beam, the cross beam has multiple spaced screw steels, and the spacing of the screw steels is 4cm-6cm.

[0017] As an embodiment, S8 is further included, after the shield machine is restarted, the ring steel pipe piece is used for support, and the truss in the upper horizontal guide and the upper vertical guide is grouted and backfilled.

[0018] The technical scheme in the application has the following technical effects: The application provides a tunnel soft rock section open type TBM escape method, by arranging an upper vertical guide, an upper horizontal guide, a left side guide and a right side guide above a shield machine, and grouting and reinforcing the soil body above the upper vertical guide and the upper horizontal guide, the deformed soil body above, on the side and at the bottom of the shield machine can be cleaned, and the surrounding soil body can be reinforced and supported, so that the surrounding soil body is prevented from collapsing or other deformation and peeling and accumulating near the cutter head, the working resistance of the cutter head of the shield machine is reduced, the shield machine can be started again to escape. In addition, the TBM escape method in the application has a small excavation range and less disturbance to the soil layer, can reduce the possibility of soil layer collapse again, is beneficial to ensuring construction safety and improving construction efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0020] Figure 1 Structure diagram for dividing the first skylight opening area into small ring steel pipe pieces on the third ring steel pipe piece in the embodiment of the present application; Figure 2 Structure diagram for setting a steel truss after the first skylight is opened in the embodiment of the present application; Figure 3 Structure diagram for setting a first grouting anchor rod and a second grouting anchor rod in the embodiment of the present application; Figure 4 Setting diagram of an upper guide and a side guide in the embodiment of the present application; Figure 5 is a top view of Figure 4 ; Figure 6 is a perspective structure diagram of Figure 4 ; Figure 7 is a top view of a second skylight in the embodiment of the present application; Figure 8 is a side view of Figure 7 ; Figure 9 is a principle diagram of a tunnel soft rock section open type TBM escape method in the embodiment of the present application.

[0021] Reference signs: 1, ring steel pipe piece; 101, third ring steel pipe piece; 102, fourth ring steel pipe piece; 2, main beam; 3, first skylight; 4, small ring steel pipe piece; 5, first grouting anchor rod; 6, second grouting anchor rod; 7, second skylight; 71, strip-shaped hole; 72, channel steel; 8, stand column; 9, threaded steel; 10, upper longitudinal guide; 11, upper transverse guide; 12, left side guide; 13, right side guide; 14, lower transverse guide. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0023] The application provides a tunnel soft rock section open type TBM escape method, which can clean the deformed soil above, on the side and at the bottom of the shield machine, can also reinforce and support the surrounding soil, reduces the working resistance of the cutter head of the shield machine, and can be started again to escape.

[0024] In order to make the above-mentioned purpose, characteristics and advantages of the application more obvious and easy to understand, the application will be further described in detail below in combination with the drawings and specific embodiments.

[0025] Specifically, as shown in the drawings, Figures 1-9 The embodiment provides a tunnel soft rock section open type TBM escape method, which comprises the following steps: S1. Determine the vertical hole position and hole size above the ring steel segment 1 near the shield tail. In the embodiment, the hole position is above the third ring steel segment 101 (the third ring steel segment 1 counted from the rear of the shield tail), and the hole size is designed to be able to clean most of the deformed soil above the shield machine and facilitate construction. Generally, the hole size can be 0.7m (length) x 1.64m (width) x 1.84m (height). In the embodiment, the length is along the forward direction of the shield machine, and the width is along the radial direction of the shield machine; the forward direction is the advancing direction of the shield machine.

[0026] S2. Grouting reinforcement is performed on the area around the hole position. After the reinforcement is completed, a first skylight 3 is cut in the third ring steel segment 101, and the soil from the hole position upwards is excavated until the set hole size is reached. Specifically, a first grouting anchor 5 and a second grouting anchor 6 are respectively arranged obliquely upwards at 2.5m and 1.5m from the rear of the hole position, the first grouting anchor 5 has 5 roots, is inclined 45° upward horizontally, and the length of each first grouting anchor 5 is 3.5m; the second grouting anchor 6 has 5 roots, is inclined 45° upward horizontally, and the length of each second grouting anchor 6 is 2.1m, and the ring spacing between adjacent two second grouting anchors 6 is 0.5m, as shown in the drawings. Figure 3 The polyurethane grouting is poured into the soil layer above the hole position through the first grouting anchor 5 and the second grouting anchor 6 to avoid the collapse of the soil above the hole position during the process of excavating the soil at the hole position. In addition, the double-layer anchor grouting can effectively increase the vertical grouting area, which not only can improve the grouting reinforcement speed to complete the grouting reinforcement work as soon as possible, but also can improve the soil reinforcement quality to avoid collapse again.

[0027] The third ring steel pipe piece 101 is directly cut, and excavation is performed upward, which is difficult. In the embodiment, a second sky window 7 is first formed on the fourth ring steel pipe piece 102 behind the third ring steel pipe piece 101. The second sky window 7 is in a grid shape, and includes a plurality of strip-shaped holes 71 arranged at intervals, and channel steels 72 arranged between the strip-shaped holes 71. The size of the strip-shaped holes 71 is 0.1 m x 0.7 m. By arranging the strip-shaped holes 71, a large amount of muck can be prevented from falling from the second sky window 7, as shown in Figs. 8 and 9. Figure 7 、 Figure 8 A worker stands behind the bottom of the second sky window 7, and loosens and excavates the soil at the hole position upward and obliquely by using an excavation tool. When excavating, the soil at the hole position can be loosened by using a tool, and then a part of the loosened soil at the hole position can be removed by using the tool, and the muck is transported out by a belt conveyor under the TBM main beam 2. After the soil at the hole position is loosened or a part of the soil at the hole position is removed, the first sky window 3 can be constructed on the third ring steel pipe piece 101. When the first sky window 3 is constructed, in order to prevent a large amount of muck from falling, the position of the first sky window 3 of the third ring steel pipe piece 101 is divided into a plurality of small ring steel pipe pieces 4, and in the embodiment, the position is divided into six small ring steel pipe pieces 4, as shown in Fig. 10. Each small ring steel pipe piece 4 is sequentially cut, and excavation is performed after each cutting is completed until the hole depth requirement is reached. Before the small ring steel pipe piece 4 is cut, the small ring steel pipe piece 4 is supported by using a column 8, and after the small ring steel pipe piece 4 is cut, the top of the hole is supported by using the column 8. The bottom of the column 8 is fixed to the shield machine main beam 2, and the fixing method can be welding. Figure 1

[0028] S3. When all the columns 8 are constructed, a horizontal beam is fixed to the top of the column 8, and a plurality of threaded steels 9 are arranged at intervals on the horizontal beam, and the adjacent threaded steels 9 are spaced apart by 5 cm, so as to stably support the soil around the hole position, as shown in Fig. 11. Figure 2

[0029] The column 8, the horizontal beam, and the threaded steel 9 in the hole position form a steel truss.

[0030] ​​S4. Grouting and reinforcing the soil above the front of the steel truss, three grouting anchor rods can be arranged here, each with a length of 2m, and arranged in a 12° upward and horizontal direction. Grouting and reinforcing the soil above the front of the steel truss is to reinforce the soil above the pre-excavation position to avoid collapse during excavation. After reinforcement, the upper longitudinal guide 10 is excavated. When excavating for the first time, personnel stand on the construction platform of the self-made stairs and excavate with hand-held electric or pneumatic picks. The single excavation length should be controlled at 0.9m, and the spoil is bagged. Personnel pass through the self-made spoil chute and are lowered to the TBM belt conveyor for transportation outside the hole. After excavation is completed, the steel truss support is constructed. With a length of 0.9m for each steel truss as a cycle, the steps of grouting and reinforcing, excavating, removing spoil, and steel truss supporting are repeated until the front of the cutter head reaches 1m~2m, and the distance is based on covering the collapse cavity area. During construction, one construction personnel is arranged for each steel truss to transfer spoil bags and remove spoil. Finally, the construction of the upper longitudinal guide 10 is completed.

[0031] S5. Construction of the upper transverse guide 11. Specifically, the construction of the upper transverse guide 11 can be carried out simultaneously when the upper longitudinal guide 10 is constructed to the collapse cavity area. The collapse cavity range above the cutter head is accurately confirmed by the upper longitudinal guide 10, and the upper transverse guide 11 is constructed based on covering the collapse cavity range. The grouting anchor rods for reinforcing the soil above the upper transverse guide 11 can be arranged in a forward and upward direction through the already arranged steel truss (the method is the same as S4), or they can be arranged in the collapse cavity area above the construction position of the upper transverse guide 11 from the already constructed upper longitudinal guide 10 to increase the reinforcing range (as shown in Figure 5 The diagonal lines on both sides of the upper longitudinal guide 10 are grouting anchor rods for the construction of the upper transverse guide 11). The upper transverse guide 11 directly removes spoil through the cutter head tooth hole and the main machine belt inside the cutter head without the need for manual transportation to the shield tail spoil chute. After the construction of the upper guide (the upper transverse guide 11 and the upper longitudinal guide 10) is completed, the concrete is sprayed to close the surrounding rock of the upper guide.

[0032] S6. Excavate from the tail of the shield to the front of the cutter head, and support the surrounding soil with the support body to obtain the left guide 12 and the right guide 13. Specifically, excavate the left guide 12 hole and the right guide 13 hole from a certain distance from the tail of the left and right shields to the front of the cutter head to reduce the constraint of the soil on the cutter head. After the excavation is completed, the cutter head is started again. If the cutter head can be started smoothly, normal tunneling is performed, and the side guides (the left guide 12 and the right guide 13) are backfilled during the tunneling process. If the cutter head cannot be started, excavate the lower horizontal guide 14 of the cutter head from the ends of the left guide 12 and the right guide 13 to the middle of the cutter head. The left guide 12 and the right guide 13 are excavated along the outside of the shield, and the excavation size is mainly used for personnel work (preferably 1.6 m high, about 2 m wide at the bottom, and 0.5 m wide at the top). The left guide 12 and the right guide 13 use steel truss or square wood frame as support, and the top of the steel truss uses a steel bar row with a spacing of 1 m per row. The excavation size of the lower horizontal guide 14 in front of the cutter head is preferably 1.6 m high and 1 m wide, and a square wood frame with a size of 200 mm*200 mm is used for support with a spacing of 0.5 m per row, and a double-layer bamboo plywood is used for protection at the top.

[0033] S7. Start the shield tunneling machine to continue the operation and realize the escape from the trouble. After the TBM successfully escapes from the trouble, the surrounding steel pipe 1 is used for support, and the steel truss in the upper guide (the upper horizontal guide 11 and the upper vertical guide 10) is filled with foam concrete for rapid setting to ensure the firmness of the soil layer above the tunnel.

[0034] The embodiment can clean the deformed soil above, on the side, and at the bottom of the shield tunneling machine, and can also reinforce and support the surrounding soil to avoid the surrounding soil from collapsing again or other deformation and piling up near the cutter head, so that the working resistance of the cutter head of the shield tunneling machine is reduced, the shield tunneling machine can be started again to escape from the trouble.

[0035] In addition, the embodiment can ensure that the anchor rod has a large insertion angle by drilling holes on the surrounding steel pipe 1 and excavating the soil, and inserting the grouting anchor rod from the drilled position. The surrounding soil above the shield can be effectively grouted and reinforced. Compared with the existing technology of reverse excavation at the rear of the shield, the excavation range is obviously reduced, the disturbance to the soil layer is smaller, the possibility of soil collapse again can be reduced, the construction safety can be ensured, and the construction efficiency can be improved.

[0036] Adaptive changes according to actual needs are within the protection scope of the present application.

[0037] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above examples are only used for helping to understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In conclusion, the content of the present specification should not be understood as the limitation of the present application.

Claims

1. A method for escaping a trapped TBM in an open section of soft rock tunnel, characterized in that, Includes the following steps: S1. Determine the location and size of the vertical opening above the annular steel tube segment near the tail of the shield; S2. Grout the area around the opening location for reinforcement. After reinforcement, cut the ring steel pipe segment below the opening location to form the first first window. Excavate the soil from the first first window upwards to the opening location until the set opening size is reached. S3. Install a steel truss inside the opening to support the surrounding soil; S4. Grout the soil above and in front of the steel truss to reinforce it. After the reinforcement is completed, excavate towards the cutterhead. After the excavation is set to a certain distance, set up the steel truss to support the surrounding soil. Repeat this process until the foremost steel truss reaches 1m to 2m in front of the cutterhead, and the upper longitudinal guide construction is completed. S5. At the location of the collapsed cavity corresponding to the upper longitudinal guide, the soil above the side is grouted for reinforcement. After the reinforcement is completed, the cutterhead is excavated laterally. After the excavation is set to a certain distance, a steel truss is set up to support the surrounding soil. This process is repeated until the length of the steel truss at the outermost end reaches the side of the cutterhead, and the construction of the upper transverse guide is completed. S6. Excavate forward from the tail of both sides of the shield to the front of the cutterhead, and use the support body to support the surrounding soil to obtain the left guide and the right guide. S7. Start the tunnel boring machine to continue operation and get out of trouble.

2. The method for escaping an open-type TBM in a soft rock section according to claim 1, characterized in that, In S7, if the tunnel boring machine fails to start, it will excavate from the front end of the left and right guides along the transverse direction to the middle, and use the support body to support the surrounding soil to obtain the lower transverse guide. Then, the tunnel boring machine will be restarted to get out of trouble.

3. The method for escaping an open-type TBM in a soft rock section according to claim 1, characterized in that, The support structure is a steel truss or a wooden frame, with the top of the wooden frame having a double layer of bamboo plywood.

4. The method for escaping an open-type TBM in a soft rock section of a tunnel according to claim 1, characterized in that, In S2, a first grouting anchor and a second grouting anchor are respectively installed diagonally upward from two designated positions behind the opening position. The length of the first grouting anchor is greater than the length of the second grouting anchor.

5. The method for escaping an open-type TBM in a soft rock section according to claim 4, characterized in that, There are 5 first grouting anchors, each with a length of 3.5m and a lateral distance of 0.5m between adjacent first grouting anchors; there are 5 second grouting anchors, each with a length of 2.1m and a lateral distance of 0.5m between adjacent second grouting anchors.

6. The method for escaping an open-type TBM in a soft rock section of a tunnel according to any one of claims 1 to 5, characterized in that, In S2, a second window is opened on the ring steel pipe segment behind the opening position. Workers stand behind the bottom of the second window and use excavation tools to loosen and excavate the soil at the opening position along the diagonal upward.

7. The method for escaping an open-type TBM in a soft rock section according to claim 6, characterized in that, In S2, when constructing the first window for the annular steel segment below the opening position, the first window position of the annular steel segment is first divided into multiple small annular steel segments, and each small annular steel segment is cut and excavated until the opening depth requirement is reached.

8. The method for escaping an open-type TBM in a soft rock section according to claim 7, characterized in that, Before the small ring steel pipe segments are cut, columns are used as supports. After the small ring steel pipe segments are cut, and the hole is excavated upward to the required depth, columns are used to support the top of the hole. The bottom of the columns is fixed to the main beam of the tunnel boring machine.

9. The method for escaping an open-type TBM in a soft rock section according to claim 8, characterized in that, The top of the columns in the steel truss has a crossbeam, and the crossbeam has multiple threaded steel bars distributed at intervals of 4cm to 6cm.

10. The method for escaping an open-type TBM in a soft rock section according to claim 8, characterized in that, It also includes S8, which uses ring steel segments for support after the tunnel boring machine restarts, and grouting backfills the trusses in the upper horizontal and upper vertical guides.

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