Strengthening method and strengthening structure for opening part of transverse passage of double-layer shield tunnel

Abstract

The present invention provides a method for strengthening the opening part of a cross-passage in a double-deck shield tunnel, including: S1. According to the opening requirements of the cross-passage, determine the opening part of the opening lining ring of the double-deck shield tunnel, and reinforce the steel bars of the opening lining ring and the adjacent lining rings on both sides of the opening lining ring; S2. On the basis of S1, strengthen the opening part of the cross-passage in the double-deck shield tunnel by using at least one of segment structure strengthening, lining ring joint strengthening and opening part strengthening. The present invention also provides a strengthening structure for the opening part of the cross-passage in the double-deck shield tunnel.

Description

Technical Field

[0001] The present invention relates to the field of tunnel structures, and particularly to a strengthening method and a strengthening structure for the opening part of a transverse passage in a double-layer shield tunnel. Background Art

[0002] Shield tunnels are widely used in fields such as highways, urban roads, and rail transit. To meet the operation requirements, for double-tunnel shield tunnels, it is usually necessary to set up transverse connection passages (referred to as "transverse passages" for short) to achieve the rapid evacuation of personnel from one tunnel to another. The construction of the transverse passage of a shield tunnel requires the removal of some segment linings of the tunnel lining ring. Currently, there are mainly the following two methods for removing segment linings in shield tunnels:

[0003] 1) Steel segment linings are set at the opening part in soft strata, some steel segment linings are removed, and a circle of steel segment linings is left around the opening.

[0004] 2) When the surrounding strata are relatively stable, reinforced concrete segment linings are used, and the reinforcement of the segment linings around the opening is appropriately strengthened to form a structure similar to a ring frame beam.

[0005] From the structures of the opening parts of the above two existing shield tunnels, both improve the structural stress during the construction period by strengthening the periphery of the opening part, and can meet the strengthening requirements of the opening structure of general shield tunnels. However, when applied to the opening of the connection passage of a single-tunnel double-layer shield tunnel that has recently emerged, the following problems exist:

[0006] 1) Compared with a single-layer shield tunnel, the opening part is generally located in the middle of the side wall of the shield tunnel. After the opening, the lining ring plus the corresponding support can meet the temporary structural stress requirements; for a single-tunnel double-layer shield tunnel, the opening part is usually located in the upper or lower part of the tunnel. After the opening, there are major risks such as the lining ring falling off or dropping, and stronger safety measures are required.

[0007] 2) The effect of strengthening the reinforcement of the segment linings is not good. Mainly because generally the reinforcement of the segment linings is already large, further strengthening the reinforcement will cause difficulties in pouring, affecting the quality of concrete; and strengthening the reinforcement has little effect on improving the stress at the corners and other parts of the segment linings.

[0008] 3) The shield tunnel lining ring is assembled by segment blocks. Only strengthening the segment structure, due to the existence of segment joints, it is difficult to form a circular structure with a ring opening; under the action of stress redistribution after removing the segment linings, the longitudinal joints at the opening part will open, affecting the overall structural stress and also being unfavorable to the overall waterproof effect of the tunnel.

[0009] 4) After the segment corresponding to the opening is removed from the opening lining ring, there is no support at the corresponding position, and the deformation of the opening ring is completely restricted by the friction force between adjacent lining rings. This method can meet the requirements when the formation stability is good. However, when the formation is poor or the size of the opening at one time is large and multiple rings need to be removed, the overall structural stability is poor and there are significant safety risks. Summary of the Invention

[0010] The purpose of the present invention is to overcome the defects of the prior art and provide a strengthening method and a strengthening structure for the opening part of the cross-passage of a double-layer shield tunnel. The present invention solves at least some of the problems in the prior art.

[0011] The present invention is implemented as follows:

[0012] The present invention provides a strengthening method for the opening part of the cross-passage of a double-layer shield tunnel, including

[0013] S1. According to the opening requirements of the cross-passage, determine the opening part of the opening lining ring of the double-layer shield tunnel, and reinforce the opening lining ring and the adjacent lining rings on both sides of the opening lining ring with steel bars.

[0014] S2. On the basis of S1, strengthen the opening part of the cross-passage of the double-layer shield tunnel by using at least one of segment structure strengthening, lining ring joint strengthening, and opening part strengthening.

[0015] Further, the segment structure strengthening is specifically as follows: According to the opening layout, determine the lining blocks around the opening. During the production process of the lining blocks around the opening, steel fibers are added to the concrete material to improve the ability of the reinforced concrete segment to resist tensile stress and local stress.

[0016] Further, the lining ring joint strengthening is specifically as follows: During the prefabrication process of the lining blocks around the opening, embedded steel plates need to be set on the inner surfaces of the segments on both sides of the circumferential and longitudinal joints. During the assembly process of the lining blocks, the two embedded steel plates at the joint are connected together through connecting steel plates.

[0017] Further, the embedded steel plates are connected to the segment concrete by anchor bars.

[0018] Further, the connecting steel plates and the embedded steel plates are connected by welding or bolts.

[0019] Further, the opening part strengthening is specifically as follows: Anchor rods or anchor cables are set on the opening lining ring for reinforcement.

[0020] Further, along the circumferential direction of the opening lining ring, anchor rods or anchor cables are set on the segments adjacent to the opening part in the circumferential direction for reinforcement.

[0021] The present invention also provides a strengthening structure for the opening part of the transverse passage of a double - layer shield tunnel: The double - layer shield tunnel includes an opening lining ring and adjacent lining rings on both sides of the opening lining ring. An opening part communicating with the transverse passage is provided on the opening lining ring. Anchor bolts or cable bolts are arranged on the segments adjacent to the opening part in the circumferential direction. Both the opening lining ring and the adjacent lining rings include opening - surrounding lining blocks. The opening - surrounding lining blocks surround the opening part. Embedded steel plates are provided on the inner surface of the segments near the circumferential and longitudinal joints of the opening - surrounding lining blocks. Two embedded steel plates at the joint are connected together through connecting steel plates.

[0022] Furthermore, steel fibers are provided inside the opening - surrounding lining blocks.

[0023] The present invention has the following beneficial effects:

[0024] The prior art mainly focuses on strengthening the segment structure within the opening range, and there are no specific and clear targeted measures for how to control the joint opening amount and segment convergence deformation, etc. A structural strengthening method for the opening part of the transverse passage of a double - layer shield tunnel proposed by the present invention gives specific implementation measures from three aspects: segment structure strengthening, lining ring joint strengthening, and opening part strengthening. Compared with the existing technology, the scheme proposed by the present invention is more systematic and comprehensive, and has strong implementability. It comprehensively considers the most unfavorable working conditions during construction and operation, and has high safety. The specific implementation effects are as follows:

[0025] By adding steel fibers during the production process of the lining blocks (opening - surrounding lining blocks) around the opening range of the transverse passage, the ability of the reinforced concrete segments to resist tensile stress and local stress is improved, and the cracking and water seepage of the concrete segments caused by stress concentration are avoided;

[0026] By strengthening the segment joints of the opening lining ring and adjacent lining blocks within the opening range with steel plate connections, the opening amount of the tunnel joints is restricted, the occurrence of joint water seepage diseases in the tunnel is avoided, and at the same time, the overall stiffness of the opening lining ring is improved;

[0027] By arranging anchor bolts or cable bolts on the opening lining ring, the convergence deformation of the opening lining ring is restricted to ensure that the convergence deformation amount will not affect the safety and normal use of the tunnel. At the same time, the fixing effect of arranging anchor bolts or cable bolts on the opening lining ring also reduces the construction risk of collapse when the shield segment is opened. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following - described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 Schematic diagram of opening holes in the double - layer shield tunnel provided by the embodiment of the present invention (taking the opening of the upper - layer connection passage as an example);

[0030] Figure 2 Schematic diagram of opening holes in the segment provided by the embodiment of the present invention (taking opening one ring as an example);

[0031] Figure 3 Provided by the embodiment of the present invention Figure 2 Partial enlarged view in;

[0032] Figure 4 Plane display of the segment joint connection provided by the embodiment of the present invention Figure 1 (taking the longitudinal joint of adjacent lining rings as an example);

[0033] Figure 5 Plane display of the segment joint connection provided by the embodiment of the present invention Figure 2 (welding the connecting steel plate and the embedded steel plate);

[0034] Figure 6 Schematic diagram of the segment opening anchor cable provided by the embodiment of the present invention.

[0035] Shown in the figure are: 1. Opening lining ring; 2. Adjacent lining rings; 3. Lining blocks around the opening; 4. Embedded steel plate; 5. Connecting steel plate; 6. Bolt or anchor cable; 7. Opening range; 8. Inner side of the segment; 9. Outer side of the segment; 10. Demolition block; 11. Circular - section shield tunnel; 12. Lane slab; 13. Upper - layer transverse passage; 14. Transverse - passage lining; 15. Fire - proof door opening. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0037] As Figures 1-6, Embodiment 1 of the present invention provides a strengthening method for the opening part of a double - layer shield tunnel cross - passage, including: S1. According to the opening requirements of the cross - passage, determine the opening part of the opening lining ring 1 of the double - layer shield tunnel, and reinforce the steel bars of the opening lining ring 1 and the adjacent lining rings 2 on both sides of the opening lining ring 1; in S1, when reinforcing the steel bars, the most unfavorable stress conditions during the construction period and the operation period need to be considered, so that the reinforcement result meets the requirements of both the ultimate limit state of bearing capacity and the serviceability limit state; S2. On the basis of S1, use at least one of segment structure strengthening, lining ring joint strengthening, and opening part strengthening to strengthen the opening part of the double - layer shield tunnel cross - passage.

[0038] The specific segment structure strengthening is as follows: According to the opening layout, determine the lining blocks 3 around the opening. During the production process of the lining blocks 3 around the opening (the diagonal shaded area in Figure 2 and Figure 3 ), add steel fibers to the concrete material to improve the ability of the reinforced concrete segments to resist tensile stress and local stress, and avoid the cracking and water seepage of the concrete segments caused by stress concentration. As Figure 2 shown, there are the opening lining ring 1, the adjacent lining ring 2, the opening range 7, and the lining blocks 3 around the opening.

[0039] The specific lining ring joint strengthening is as follows: During the prefabrication of the lining blocks 3 around the opening, embedded steel plates 4 need to be set on the inner surface of the segments on both sides of the circumferential and longitudinal joints (the longitudinal direction is the length direction of the double - layer shield tunnel). During the assembly process of the lining blocks, connect the two embedded steel plates 4 at the joint through a connecting steel plate 5. As Figure 4 , the arrow in the figure indicates the tunneling direction. The segment joints of the two adjacent lining rings 2 along the tunneling direction are connected by the connecting steel plate 5, and the connecting steel plate 5 connects the embedded steel plates 4 on both sides of the longitudinal joint. The connecting steel plate 5 is connected to the embedded steel plate 4 by welding or bolts; the segment joints of the lining blocks 3 around the opening are strengthened by steel plate connection to limit the opening amount of the joint and improve the overall stiffness of the segments.

[0040] As Figure 5 , the embedded steel plate 4 is reliably connected to the segment concrete by anchor bars. The embedded steel plate 4 is arranged on the inner side 8 of the segment. The inner side 8 of the segment is the side of the segment located inside the tunnel, which is convenient for welding with the connecting steel plate 5. The side of the segment facing away from the tunnel driving passage is the outer side 9 of the segment.

[0041] The specific opening part strengthening is as follows: Set anchor bolts or anchor cables 6 on the opening lining ring 1 for reinforcement. Along the circumferential direction of the opening lining ring 1, set anchor bolts or anchor cables 6 on the segments adjacent to the opening part in the circumferential direction for reinforcement. Figure 6 Shown are the anchor bolts or anchor cables 6 and the removal block 10. After removing the removal block 10, the opening part is obtained.

[0042] Embodiment 2 of the present invention provides a reinforcement structure for the opening part of a double-layer shield tunnel: The double-layer shield tunnel includes an opening lining ring 1 and adjacent lining rings 2 on both sides of the opening lining ring 1. An opening part communicating with a transverse passage (transverse connection passage) is provided on the opening lining ring 1. Anchor bolts or cable bolts 6 are arranged on the segments adjacent to the opening part in the circumferential direction. Both the opening lining ring 1 and the adjacent lining rings 2 include opening peripheral lining blocks 3. Steel fibers are provided in the opening peripheral lining blocks 3. The opening peripheral lining blocks 3 surround the opening part. Embedded steel plates 4 are provided on the inner surface of the segments near the circumferential and longitudinal joints (the inner surface of the segment is the side located inside the tunnel). The two embedded steel plates 4 at the joint are connected together by a connecting steel plate 5. As Figure 2 shown, there are an opening lining ring 1, adjacent lining rings 2, an opening range 7, and opening peripheral lining blocks 3.

[0043] Remove the segments within the opening range on the previously assembled opening lining ring 1 from the inside of the double-layer shield tunnel. The shield tunnel is formed by segment assembly. Before removing the segments at the opening part, connect the segment joints with the connecting steel plate 5 to ensure that the embedded steel plates 4 at the joints of the opening peripheral lining blocks 3 are connected to the connecting steel plate 5. Before removing the segments at the opening part, arrange anchor bolts or cable bolts 6 on the opening lining ring 1.

[0044] In view of the safety risks and the risk of water leakage during the operation period existing in the structure of the opening part of the existing double-layer shield tunnel transverse passage, the present invention proposes a method for strengthening the structure of the opening part of the double-layer shield tunnel transverse passage.

[0045] A method for strengthening the structure of the opening part of a double-layer shield tunnel transverse passage includes three ways of segment structure strengthening, lining ring joint strengthening, and opening part strengthening.

[0046] The segment structure strengthening is to add steel fibers to the peripheral segments of the opening part to improve the ability of the reinforced concrete segments to resist tensile stress and local stress;

[0047] The lining ring joint strengthening is to strengthen the joints of the peripheral segments of the opening part, and use embedded steel plates and welded steel plates before opening the hole for strengthening;

[0048] The opening part strengthening is to reinforce the circumferentially adjacent segments of the opening part with anchor bolts or cable bolts; Two to three of the above three reinforcement methods can be selected according to the diameter of the shield tunnel and the engineering geological conditions of the opening part.

[0049] The present invention proposes a method for strengthening the structure of the opening part of a double-layer shield tunnel transverse passage. The technical solution of the present invention is:

[0050] Measure 1: According to the requirements of the cross-passage opening, determine the opening positions of the opening lining ring 1 of the shield tunnel, and strengthen the structural reinforcement of the opening lining ring 1 and the adjacent lining ring 2.

[0051] After the shield tunnel is opened, the original closed circular ring stress system of the segment changes into an open structure system with a worse stress condition, and the internal force of the segments in the opening range changes. According to the calculation results, it is necessary to strengthen the structural reinforcement of the segments of the opening lining ring 1 and the adjacent lining ring 2 to meet the requirements of the ultimate limit state of bearing capacity and the serviceability limit state under the most unfavorable working conditions.

[0052] Measure 2: According to the opening layout, determine the lining blocks 3 around the opening, and add steel fibers during the manufacturing process to improve the ability of the reinforced concrete segments to resist tensile stress and local stress.

[0053] During the construction and operation of the shield tunnel, deformation will inevitably occur. Since some segments of the opening lining ring 1 of the shield tunnel are removed and connected to the lining structure of the connecting passage, the overall stiffness changes suddenly compared with the shield tunnel segments before and after, which is likely to cause local stress concentration, resulting in diseases such as segment breakage and water seepage. To avoid the segment quality problems caused by local stress concentration, the present invention proposes to add steel fibers during the manufacturing process of the lining blocks around the opening range of the cross-passage (the lining blocks 3 around the opening) to improve the ability of the reinforced concrete segments to resist tensile stress and local stress.

[0054] Measure 3: Embed steel plates 4 on the inner surface of the segments on both sides of the joint around the opening during the manufacturing of the segments. Before the shield tunnel segments are assembled and the segments at the opening part are removed, connect the segment joints with steel plates 5, and the connection method can be welding or bolt connection, etc.

[0055] To avoid excessive opening of the segment joints caused by the reduction of the overall stiffness of the lining ring after some segments of the shield tunnel are removed, the present invention proposes to strengthen the connection of the segment joints of the lining blocks 3 around the opening near the opening range with steel plates to limit the opening of the tunnel circumferential joints and improve the overall stiffness of the opening lining ring.

[0056] Measure 4: Before the shield tunnel segments are assembled and the segments at the opening part are removed, set bolts or cables 6 in the opening ring (the opening lining ring 1) and set anchor points in the opening ring to limit the deformation of the lining ring after opening.

[0057] To avoid excessive convergence deformation of the opening lining ring 1 caused by the reduction of the overall stiffness of the lining ring after some segments of the shield tunnel are removed, radial bolts or cables 6 can be set in the opening lining ring 1 before the segments are removed, and the anchor points are located on the opening lining ring 1. Through the restraint of the bolts or cables, the convergence deformation of the opening lining ring 1 can be effectively limited.

[0058] The above Measure 1 is the basic measure during the opening of the shield tunnel. Measures 2, 3, and 4 should be determined comprehensively based on the structural forces and deformations of the opening lining ring and the adjacent lining rings after the shield tunnel is opened. In the most unfavorable case, the structural strengthening method of Measure 2 + Measure 3 + Measure 4 can be adopted on the basis of Measure 1.

[0059] The following will further elaborate on the device of the present invention in conjunction with the attached Figures 1-6 drawings.

[0060] As Figure 1 shown, taking the opening of the upper cross passage in the double - layer shield tunnel as an example, the opening position is in the upper side. After the opening, the non - closed structure of the lining ring is in an unstable state, and there is a relatively serious risk of the top segment falling off and sagging.

[0061] Figure 2 This is a schematic diagram of the opening position of the double - layer shield tunnel of the present invention. To construct the cross passage, it is necessary to remove the segments within the opening range on the originally assembled lining ring 1 from the inside of the shield tunnel. However, the removal of the segments will destroy the closed circular ring force system of the original lining ring 1, becoming a relatively unfavorable open - structure system, and the overall stiffness will also decrease. Under the action of external water and soil loads, the internal forces and deformations of the segments will also increase. Therefore, it is necessary to strengthen the segment structure within the cross - passage range.

[0062] As Figure 2 shown, it is necessary to carry out reinforcement design for the opening lining ring 1 and the adjacent lining rings (adjacent lining ring 2) on the left and right sides. The calculation needs to comprehensively consider the most unfavorable stress conditions during the construction period and the operation period. The reinforcement results should meet the requirements of both the ultimate limit state of bearing capacity and the serviceability limit state.

[0063] As Figure 2 shown, according to the opening layout, the surrounding lining block 3 is determined. During the production process of the surrounding lining block 3, steel fibers are added to the concrete material to improve the ability of the reinforced concrete segment to resist tensile stress and local stress, and to avoid segment quality problems caused by stress concentration during construction and operation;

[0064] As Figure 2 shown, during the prefabrication process of the surrounding lining block 3, steel plates 4 need to be embedded at the circumferential and longitudinal joints. During the segment assembly process, reliable connection is carried out through welding of the connecting steel plates 5 to limit the opening amount of the joints and improve the overall stiffness of the segments. The detailed drawing of the embedded steel plate 4 is as Figure 5 shown. The embedded steel plate 4 is reliably connected to the segment concrete by anchor bars. Before the opening of the shield segment, it is necessary to complete the connection between the embedded steel plate 4 at the joint of the surrounding lining block 3 and the connecting steel plate 5.

[0065] As Figure 6As shown in the figure, before the opening of the shield segment, radial bolts or cables 6 can be constructed inside the tunnel, and the anchoring points are located on the opening lining ring 1. The length, diameter, range, and spacing of the bolts or cables 6 need to be specifically designed according to the engineering geological conditions to effectively limit the convergence deformation of the opening lining ring 1.

[0066] The above is only the basic principle and main measures for the structural strengthening of the opening part of the cross-passage in the shield tunnel of the present invention, and does not impose any specific quantity, size, shape, and material restrictions on the implementation method of the present invention. Therefore, all possible corresponding modifications and equivalents that can be utilized belong to the scope of the patent applied for by the present invention.

[0067] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0068] The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A strengthening method for the opening part of a transverse passage in a double-layer shield tunnel, characterized in that: Including S1, according to the requirements of the cross-passage opening, determine the opening positions of the opening lining rings of the double-layer shield tunnel, and reinforce the steel bars of the opening lining rings and the adjacent lining rings on both sides of the opening lining rings; in S1, when reinforcing the steel bars, the most unfavorable stress conditions during the construction period and the operation period need to be considered, so that the reinforcement results meet the requirements of both the ultimate limit state of bearing capacity and the serviceability limit state; S2, on the basis of S1, adopt reinforcement methods such as segment structure reinforcement, lining ring joint reinforcement and opening part reinforcement to reinforce the cross-passage opening part of the double-layer shield tunnel; the specific segment structure reinforcement is: according to the opening layout, determine the lining blocks around the opening. During the production of the lining blocks around the opening, steel fibers are added to the concrete material to improve the ability of the reinforced concrete segments to resist tensile stress and local stress, and avoid the cracking and water seepage of the concrete segments caused by stress concentration; the specific lining ring joint reinforcement is: during the prefabrication of the lining blocks around the opening, embedded steel plates need to be set on the inner surfaces of the segments on both sides of the circumferential and longitudinal joints. During the assembly of the lining blocks, the two embedded steel plates at the joint are connected together by connecting steel plates. The segment joints of the lining blocks around the opening are reinforced by steel plate connection to limit the opening amount of the tunnel joints and avoid the occurrence of joint water seepage diseases in the tunnel. At the same time, the overall stiffness of the opening lining ring is improved; the embedded steel plates are connected to the segment concrete by anchor bars; the connecting steel plates are connected to the embedded steel plates by welding or bolts; the specific opening part reinforcement is: set anchor bolts or anchor cables on the opening lining ring for reinforcement. By setting anchor bolts or anchor cables on the opening lining ring, the convergence deformation of the opening lining ring is restricted to ensure that the convergence deformation amount will not affect the safety and normal use of the tunnel. At the same time, the fixing effect of setting anchor bolts or anchor cables on the opening lining ring also reduces the construction risk of collapse during the opening of the shield segments. Along the circumferential direction of the opening lining ring, anchor bolts or anchor cables are set on the segments adjacent to the opening part in the circumferential direction for reinforcement.

2. A strengthening structure for the opening part of a double-layer shield tunnel cross-passage, which adopts the strengthening method for the opening part of a double-layer shield tunnel cross-passage as described in Claim 1, and is characterized in that: The double-layer shield tunnel includes an opening lining ring and adjacent lining rings on both sides of the opening lining ring. An opening part communicating with the cross-passage is opened on the opening lining ring. Anchor bolts or anchor cables are set on the segments adjacent to the opening part in the circumferential direction. The opening lining ring and the adjacent lining rings both include lining blocks around the opening. Steel fibers are provided in the lining blocks around the opening. The lining blocks around the opening surround the opening part. Embedded steel plates are provided on the inner surfaces of the segments near the circumferential and longitudinal joints. The two embedded steel plates at the joint are connected together by a connecting steel plate.

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