Multi-frequency seismic zone large-diameter slurry shield method

Abstract

The application discloses a method for constructing a large-diameter slurry shield tunnel by using a multi-frequency seismic belt, and comprises the following steps: S1, acquiring tunnel size parameters and determining single-pipe size parameters according to the tunnel size parameters; S2, presetting first and last ring pipes, embedding a first steel plate on the outer side of the first and last ring pipes in the ring direction when the first and last ring pipes are formed, and arranging a waterproof rubber strip on the inner side of the first steel plate close to the first and last ring pipes; S3, assembling a shield tunneling machine and adjusting parameters of the shield tunneling machine, and stopping the shield tunneling machine when the shield tunneling machine is excavated to the first and last ring positions of the tunnel; S4, installing the first and last ring pipes, and controlling the first steel plates in each adjacent first and last ring pipe to be aligned in the ring direction, and the waterproof rubber strips to be aligned in the ring direction, so as to form a ring-direction waterproof ring; and S5, continuing shield tunneling and synchronously grouting between the installed pipe segments and the soil, so as to stabilize the peripheral soil. The technical scheme aims to improve waterproof sealing performance during shield tunneling construction and after the tunnel is completed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield tunneling engineering, and in particular to a large-diameter slurry shield method for a multi-frequency earthquake zone. BACKGROUND

[0002] In the field of shield tunneling engineering, the waterproof sealing performance of the first and last ring segments is closely related to the overall reliability of the tunnel. At the two ends of the tunnel (i.e., the positions where the first and last ring segments are arranged), the structure is open to communicate with the shaft, and insufficient waterproof sealing performance may cause groundwater to penetrate into the tunnel, directly affecting the safety and progress of construction, and adversely affecting the overall project.

[0003] In the related art, no special structural requirements are proposed for the first and last ring segments during shield construction. As a result, in the construction phase, if strong rainfall or extreme weather occurs, groundwater is prone to penetrate into the tunnel through the two ends of the tunnel. At the same time, as time goes by, the waterproof strips arranged at the positions of the first and last ring segments in the related art are exposed to the external environment for a long time, which rapidly shortens the service life of the waterproof strips, and thus the waterproof sealing performance decreases in the use phase after the completion of tunnel construction, causing groundwater to penetrate into the tunnel.

[0004] Therefore, how to solve the problem of insufficient waterproof sealing performance during tunnel shield construction and after the completion of the tunnel has become an urgent problem to be solved in the industry. SUMMARY

[0005] The main purpose of the present application is to provide a large-diameter slurry shield method for a multi-frequency earthquake zone, aiming to improve the waterproof sealing performance during tunnel shield construction and after the completion of the tunnel.

[0006] To achieve the above-mentioned purpose, the present application provides a large-diameter slurry shield method for a multi-frequency earthquake zone, which comprises the following steps: step S1, obtaining tunnel size parameters and determining single-segment size parameters according to the tunnel size parameters; step S2, prepositioning the first and last ring segments, and pre-embedding a first steel plate on the outer side of the ring of the first and last ring segments when forming the first and last ring segments, and arranging a waterproof strip on the inner side of the ring of the first steel plate close to the first and last ring segments; step S3, assembling the shield machine and adjusting the parameters of the shield machine, and controlling the shield machine to stop when tunneling to the first and last ring positions; step S4, installing the first and last ring segments, and controlling the alignment of the first steel plates in each adjacent first and last ring segment along the ring of the tunnel, and the alignment of each waterproof strip along the ring, to form a ring-shaped waterproof ring; step S5, continuing shield tunneling, and simultaneously grouting between the installed segment and the soil body to stabilize the peripheral soil body.

[0007] In some embodiments, in step S2, embedding the first steel plate on the outer side of the ring of the first and last ring-shaped pieces includes the following sub-steps: step S21, forming the first steel plate into an arc shape, and welding anchor bars on the inner side of the ring of the first steel plate; step S22, attaching a waterproof rubber strip, and controlling the waterproof rubber strip to be arranged along the ring of the first steel plate; and step S23, grouting and forming, installing the first steel plate with the welded anchor bars and the attached waterproof rubber strip into a mold, and forming the first and last ring-shaped pieces after the grout solidifies.

[0008] In some embodiments, in the step of attaching the waterproof rubber strip, the waterproof rubber strip is attached on the inner side of the ring of the first steel plate.

[0009] In some embodiments, when forming the first and last ring-shaped pieces, a second steel plate is also embedded at the first end of the first and last ring-shaped pieces, at least part of the second steel plate protrudes from the first end; and the first end is located at one end of the first and last ring-shaped pieces in a direction perpendicular to the ring.

[0010] In some embodiments, embedding the first steel plate on the outer side of the ring of the first and last ring-shaped pieces and embedding the second steel plate at the first end of the first and last ring-shaped pieces includes: forming the first steel plate into an arc shape and forming the second steel plate into a plate shape; welding anchor bars on the inner side of the ring of the first steel plate and on the second steel plate, and attaching a waterproof rubber strip on the inner side of the ring of the first steel plate; and installing the first steel plate and the second steel plate into a mold, grouting and forming the first and last ring-shaped pieces, so that the first steel plate is located on the outer side of the ring of the first and last ring-shaped pieces, and at least part of the second steel plate protrudes from the first end of the first and last ring-shaped pieces.

[0011] In some embodiments, when attaching the waterproof rubber strip on the inner side of the ring of the first steel plate, the waterproof rubber strip is controlled to be arranged close to the second end; and the second end is arranged away from the first end in a direction perpendicular to the ring of the first and last ring-shaped pieces.

[0012] In some embodiments, when welding the anchor bars to the second steel plate, a punch plug welding method is used, so that the anchor bars pass through the second steel plate in the thickness direction of the second steel plate; and after grouting and forming the first and last ring-shaped pieces, at least part of the anchor bars is located outside the first and last ring-shaped pieces, and the part of the anchor bars located outside the first and last ring-shaped pieces is connected to the supporting structure in the shaft.

[0013] In some embodiments, the carrying capacity of a single anchor bar welded to the second steel plate is calculated by the following formula:

[0014] ;

[0015] wherein C is the carrying capacity of a single anchor bar, d is the diameter of the anchor bar, f t is the tensile strength of the anchor bar material, and S is a safety factor, and the value range of S is 1.5 to 3.0. σ

[0016] ​In some embodiments, in a direction perpendicular to the circumferential direction of the first and last ring segments, the anchor bars welded to the first steel plate and the anchor bars welded to the second steel plate are staggered.

[0017] In some embodiments, after the first and last ring segments are grouted and formed, anti-corrosion coating is applied to the portion of the first steel plate protruding from the circumferential outside of the first and last ring segments, and the portion of the second steel plate protruding from the first end, to form an anti-corrosion coating layer; the thickness of the anti-corrosion coating layer is controlled to be no less than 50 μm.

[0018] The technical solution of the present invention is to pre-install the first and last ring segments, and pre-embed the first steel plate on the circumferential outer side of the first and last ring segments, and set a waterstop strip on the circumferential inner side of the first steel plate close to the first and last ring segments. At the same time, when installing the first and last ring segments, the circumferential direction of the tunnel is controlled, and the first steel plates in each adjacent first and last ring segments are circumferentially aligned, and each waterstop strip is circumferentially aligned to form an circumferential waterstop ring. The water-stop expansion performance of the waterstop strip can be used to reduce the risk of groundwater continuing to penetrate into the tunnel, and the first steel plate can seal the waterstop strip on the circumferential inner side of the first and last ring segments, thereby reducing the contact of the waterstop strip with the outside world, providing protection for the waterstop strip, reducing the aging rate of the waterstop strip, and improving the waterproof sealing and reliability during tunnel shield construction and after the tunnel is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1 A cross-sectional view of the first ring segment along the tunnel axis in a large-diameter slurry shield method for a multi-frequency earthquake zone provided by one embodiment of the present invention;

[0021] Figure 2 A flowchart of a large-diameter slurry shield method for a multi-frequency earthquake zone provided by one embodiment of the present invention;

[0022] Figure 3 A flowchart of the sub-steps of step S2 in a large-diameter slurry shield method for a multi-frequency earthquake zone provided by one embodiment of the present invention;

[0023] Figure 4 This is a flowchart of the sub-steps of step S2 in a large-diameter slurry shield method for a multi-frequency earthquake zone provided by another embodiment of the present invention.

[0024] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0026] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0027] In addition, if the embodiments of the present application involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel solutions are included, for example, "A and / or B" includes A solution, or B solution, or A and B solutions are satisfied at the same time. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present application.

[0028] In the multi-frequency earthquake zone, large-diameter slurry shield construction faces challenges such as frequent earthquakes, poor soil stability, high risk of water gushing, and the like, which are related to construction safety and long-term durability of the tunnel. In the initial stage of large-diameter slurry shield construction in the multi-frequency earthquake zone, it is usually necessary to optimize segment design and installation process to enhance the seismic resistance and waterproofness of the tunnel structure. Traditional methods such as standard segment assembly or simple water stop measures are prone to problems such as segment misalignment, leakage, or structural failure in earthquake zones. During tunnel construction using the slurry shield method, segment installation, tunneling process, and seismic disturbance can all cause soil deformation and structural damage, resulting in multiple risks that cause tunnel settlement or leakage to exceed the control standard range. Based on this, how to safely and efficiently implement large-diameter slurry shield construction in the multi-frequency earthquake zone and maintain structural stability and waterproof performance at each stage of construction has become a problem that needs to be solved in the industry.

[0029] In the field of shield tunneling engineering, the waterproof sealing performance of the first and last ring segments is closely related to the overall reliability of the tunnel. At the two ends of the tunnel (i.e., the positions where the first and last ring segments are arranged), the structure is open to communicate with the shaft, and insufficient waterproof sealing performance may cause groundwater to penetrate into the tunnel, directly affecting the safety and progress of construction, and adversely affecting the overall project.

[0030] In the related art, no special structural requirements are proposed for the first and last ring segments during shield tunneling. As a result, in the construction phase, if strong rainfall or extreme weather occurs, groundwater is prone to penetrate into the tunnel through the two ends of the tunnel. Meanwhile, as time goes by, the waterproof rubber strips arranged at the positions of the first and last ring segments in the related art are exposed to the external environment for a long time, which rapidly shortens the service life of the waterproof rubber strips, and thus the waterproof sealing performance decreases in the use phase after the completion of tunnel construction, causing groundwater to penetrate into the tunnel.

[0031] Therefore, how to solve the problem of insufficient waterproof sealing performance during tunnel shield construction and after the completion of the tunnel has become a difficult problem to be solved in the industry. Based on this, a large-diameter slurry shield method suitable for a multiple-frequency earthquake zone is designed, which can effectively improve the waterproof sealing performance and reliability of the first and last ends of the tunnel, i.e., the positions of the first and last rings.

[0032] Please refer to Figures 1 to 4 The present application provides a large-diameter slurry shield method suitable for a multiple-frequency earthquake zone, which comprises the following steps:

[0033] Step S1, obtain the tunnel size parameters, and determine the size parameters of a single segment according to the tunnel size parameters. In this step, the tunnel size parameters (such as tunnel diameter, length, etc.) are obtained, and the size parameters (such as width, arc length, etc.) of a single segment are determined accordingly, to ensure that the segment design matches the requirements of the tunnel.

[0034] When constructing a large-diameter tunnel in a multiple-frequency earthquake zone, the accurate determination of the segment size is the first step. By obtaining the tunnel size parameters, a single segment can be reasonably designed to adapt to the dynamic load of the earthquake zone.

[0035] Among them, the tunnel size parameters are the basic data that determine the geometric shape of the segment, and the tunnel cross-sectional profile can be obtained by laser scanning or geological radar to calculate the arc length and thickness of the segment. The first and last ring segments refer to the first ring and the last ring segments located at the opening ends of the tunnel, and their special structural design can prevent groundwater from penetrating along the opening ends.

[0036] Step S2, preposition the first and last ring segments, and when forming the first and last ring segments, a first steel plate 10 is pre-embedded on the outer side of the first and last ring segments in the ring direction, and a waterproof rubber strip 20 is arranged on the inner side of the first steel plate 10 close to the first and last ring segments in the ring direction.

[0037] The first steel plate 10 can improve the rigidity of the first and last ring segments in the thickness direction and improve the structural strength of the first and last ring segments. Meanwhile, the first steel plate 10 can also cooperate with the main structure of the first and last ring segments to seal the waterstop rubber strip 20, reduce the exposure of the waterstop rubber strip 20 in the external environment, and reduce the aging rate of the waterstop rubber strip 20, thereby being more reliable.

[0038] In the embodiments of the present application, the first steel plate 10 and the waterstop rubber strip 20 are both embedded in the mold when the first and last ring segments are formed. After the slurry is placed in the mold, the first steel plate 10 and the waterstop rubber strip 20 are integrally formed with the main structure of the first and last ring segments. The first steel plate 10 and the waterstop rubber strip 20 are embedded to enhance the tensile strength and waterproof sealing performance of the segments.

[0039] The first steel plate 10 is a rigid support member and can be made of a corrosion-resistant alloy steel plate embedded on the outside of the segment to enhance the structural deformation resistance. The waterstop rubber strip 20 can be made of a ternary ethylene-propylene rubber material and is continuously laid along the inside of the steel plate to form an elastic sealing layer.

[0040] Step S3: Assembling the shield machine and adjusting the parameters of the shield machine to stop the shield machine when it excavates to the first and last ring positions of the tunnel.

[0041] This step is a step for the shield machine when it is excavating. Assembling the shield machine and adjusting the parameters of the shield machine means that after the parts of the shield machine are transported into the shaft, the shield machine is assembled and the parameters such as the thrust force and the mud pressure of the shield machine are adjusted and configured. The shield machine stops when it excavates to the first ring position, so as to assemble the first ring segment of the tunnel. The adjustment of the parameters of the shield machine needs to consider the characteristics of the soil in the earthquake zone to ensure the stability of the excavation.

[0042] As the tunnel is constructed, the shield machine stops when it excavates to the last ring position of the tunnel, so as to assemble the last ring segment of the cableway.

[0043] Step S4: Installing the first and last ring segments and controlling the first steel plates 10 in each adjacent first and last ring segment to be aligned in the ring direction, and the waterstop rubber strips 20 to be aligned in the ring direction to form a ring-shaped waterstop ring.

[0044] This step is a step for installing the segments. After the shield machine completes the shield at the first ring position, the first ring segment is installed at the first ring position to form a ring-shaped support structure. It can be understood that the construction workers need to sequentially splice the first ring segments in the ring direction to form a ring-shaped support structure.

[0045] In this step, the first steel plates 10 in each adjacent first and last annular segment are aligned in the circumferential direction, and each waterstop rubber strip 20 is aligned in the circumferential direction to form a circumferential waterstop ring. In the step of prepositioning the first and last annular segments in step S2, the first steel plates 10 and the waterstop rubber strips 20 are prearranged along the circumferential direction of the segment, and the two ends of the first steel plates 10 and the waterstop rubber strips 20 along the circumferential direction are exposed on the segment. Thus, in the segment assembly step in this step, only the exposed first steel plates 10 and waterstop rubber strips 20 of each segment need to be spliced, thereby achieving the alignment of the first steel plates 10 in each adjacent first and last annular segment in the circumferential direction, and the alignment of each waterstop rubber strip 20 in the circumferential direction to form a circumferential waterstop ring.

[0046] After the assembly of the first annular segment is completed (only the first annular segment is described in this application, and the last annular segment is similar and will not be described again), a circumferential waterstop ring can be formed. When groundwater seeps into the first annular segment, the waterstop rubber strip 20 will swell in water to fill the gaps and holes in the interior of the first annular segment and during the splicing of adjacent first annular segments, thereby achieving the effect of water controlling water and controlling the spread of water into the tunnel formed by the segment.

[0047] It should be noted that the ordinary segment will also be provided with a corresponding waterstop rubber strip structure, and the material and structure of the segment mechanism itself will also take into account the influence of groundwater seepage, that is, the ordinary segment itself has a certain ability to prevent groundwater seepage. In these embodiments of the present application, the circumferential waterstop ring formed by the waterstop rubber strip 20 is mainly aimed at alleviating the groundwater seepage along the axial direction of the tunnel (the direction of the shield of the shield tunneling machine). The reason for this is that at the position of the first and last annular segments, which are usually the positions where the tunnel communicates with the launching shaft and the receiving shaft, one end of the first and last annular segments is an open structure along the axial direction of the tunnel, and the other end is a structure for splicing with ordinary segments. At this time, in the initial stage of tunnel construction, when the external rainfall is relatively abundant, water flow is easy to penetrate in the segment along the axial direction of the tunnel. Therefore, the structure of the aforementioned circumferential waterstop ring needs to be provided at the position of the first and last annular segments to alleviate this water flow penetration and further improve the waterproof performance of the tunnel during construction and subsequent use.

[0048] In these embodiments of the present application, the waterstop rubber strip 20 is arranged on the inner side of the first steel plate 10 close to the circumferential direction of the first and last annular segments, that is, the waterstop rubber strip 20 is arranged on the side of the first steel plate 10 close to the tunnel space, in order to reduce the risk of the waterstop rubber strip 20 being eroded by ordinary groundwater and swelling prematurely, thereby alleviating the risk of rainwater penetrating along the axial direction of the tunnel when the rainfall is more abundant, and thus improving the waterproof sealing performance during tunnel shield construction and after the completion of the tunnel.

[0049] Step S5, continue shield tunneling, and simultaneously grout between the installed segment and the soil body to stabilize the peripheral soil body.

[0050] The main feature of the method is to strengthen the waterproof design of the pipe piece structure (such as the pre-embedded first steel plate 10) and the waterproof strip 20 according to the characteristics of the seismic belt, and to realize deformation control through circumferential alignment and synchronous grouting. Compared with the prior art, the method can more effectively resist seismic disturbance and reduce the risk of leakage and settlement.

[0051] According to the multi-frequency seismic belt large-diameter slurry shield method provided by the embodiments of the present application, the traditional method relies on a single waterproof strip and does not form a continuous sealing structure. The present application constructs a double waterproof system through the synergistic effect of the pre-embedded steel plate and the strip. The steel plate provides rigid support to prevent the strip from being compressed too much, and the strip compensates for the gap caused by the installation error of the steel plate. The circumferential alignment design ensures that the waterproof structure is continuously closed in the circumferential direction, avoiding the occurrence of weak points of leakage. Synchronous grouting not only reinforces the soil, but also forms a secondary waterproof barrier around the pipe piece, effectively blocking the groundwater infiltration path.

[0052] Through the above technical solutions, the present application solves the risk of groundwater infiltration in the first and last ring pipe piece area, forming a multi-level waterproof system. The combination design of rigid steel plate and elastic strip improves the durability of the sealing structure, the circumferential alignment process ensures the continuity of the waterproof interface, and synchronous grouting reinforces the stability of the soil. This scheme significantly reduces the incidence of leakage accidents during construction, prolongs the service life of the tunnel, and is especially suitable for large-diameter tunnel projects in earthquake-prone areas.

[0053] In some embodiments, in step S2, pre-embedding the first steel plate 10 on the circumferential outside of the first and last ring pipe piece includes the following sub-steps: step S21, forming an arc-shaped first steel plate 10, and welding anchor bars 40 on the circumferential inside of the first steel plate 10.

[0054] The arc-shaped first steel plate 10 refers to a curved metal plate that matches the shape of the tunnel in the circumferential direction. It can be formed by rolling process, and the radius of curvature can be 1.05 to 1.2 times the design radius of the tunnel. This structure can adapt to the profile of the pipe piece on the circumferential outside, improving the tightness of the steel plate and the concrete.

[0055] The anchor bar 40 refers to a metal reinforcing member welded on the inside of the steel plate. It can be made of threaded steel or round steel, such as steel bars with a diameter of 8 to 12 mm, which are fixed to the surface of the steel plate by arc welding. The anchor bar 40 can enhance the mechanical interlocking force between the steel plate and the concrete, preventing the steel plate from shifting during grouting.

[0056] Step S22, attaching a waterproof strip, controlling the waterproof strip to be arranged along the circumferential direction of the first steel plate 10. Further, in these embodiments of the present application, in the step of attaching the waterproof strip, the waterproof strip is attached to the circumferential inside of the first steel plate 10.

[0057] The inner side in the ring direction refers to the direction along the inner surface of the arc profile of the segment, which can be achieved by setting a rubber strip mounting groove on the inner arc surface of the steel plate, so as to ensure that the rubber strip is tightly attached to the steel plate. The waterproof rubber strip refers to fixing a flexible sealing material on the surface of the steel plate, which can be achieved by using an adhesive or a mechanical buckle, so that the rubber strip forms a continuous sealing interface with the contact surface of the adjacent segment during the segment assembly process.

[0058] Specifically, in the manufacturing stage of the first and last ring segments, the first steel plate 10 is pre-embedded on the outer side of the ring of the segment, and the waterproof rubber strip is fixed on the inner arc surface of the steel plate. When the segments are assembled, the inner arc surface rubber strips of the steel plates of adjacent segments are pressed against each other to form a continuous water stop along the ring of the tunnel. Since the rubber strip is wrapped on the inner side by the steel plate, it is avoided to be directly exposed to the external water and soil environment, thereby reducing external mechanical damage and chemical corrosion.

[0059] Compared with the prior art, the traditional method directly arranges the waterproof rubber strip on the outer surface of the segment, and the rubber strip is in long-term contact with groundwater or corrosive substances in the soil, which causes the material to age rapidly. The present scheme internally embeds the rubber strip between the steel plate and the concrete, forms a physical barrier to isolate the external environment, and at the same time, the rubber strip can still achieve effective sealing through the contact pressure between the steel plates during assembly.

[0060] Step S23, grouting and forming, the first steel plate 10 with welded anchor bars 40 and completed waterproof rubber strip installation is installed into the mold, and the first and last ring segments are formed after the grout is solidified and formed. Among them, along the ring direction of the first and last ring segments, the two ends of the waterproof rubber strip need to be exposed.

[0061] The present application further proposes a first steel plate 10 formed in an arc shape, and an anchor bar 40 welded on the inner side of the ring direction of the first steel plate 10; the waterproof rubber strip is installed, and the waterproof rubber strip is arranged along the ring direction of the first steel plate 10; grouting and forming, the first steel plate 10 with welded anchor bars 40 and completed waterproof rubber strip installation is installed into the mold, and the first and last ring segments are formed after the grout is solidified and formed. Among them, along the ring direction of the first and last ring segments, the two ends of the waterproof rubber strip need to be exposed.

[0062] Among them, the two ends of the waterproof rubber strip are exposed, which means that the rubber strip extends out of the surface of the concrete at both ends in the ring direction, for example, the exposed length of each end can be 10 to 20 mm. The exposed rubber strip forms a continuous sealing interface when the adjacent segments are assembled, avoiding leakage at the joint.

[0063] Specifically, in the manufacturing process of the first and last ring segments, the arc-shaped steel plate is first processed into a preset arc and welded with anchor bars 40, and then the waterproof rubber strip is pasted along the inner side of the ring direction of the steel plate. When grouting, the steel plate is fixed in the mold, the concrete wraps the anchor bars 40 and covers the inner side area of the steel plate, but the two ends of the rubber strip remain exposed. After the segment is demolded, the steel plate is embedded in the outer side of the concrete ring, and the two ends of the rubber strip form a continuous sealing surface that can be connected with the rubber strip of other segments.

[0064] Compared with the prior art, the traditional segment generally only sets a waterproof layer on the concrete surface, and the rubber strip is directly pasted at the concrete joint, which is easy to cause the rubber strip to fall off or the sealing to fail due to the uneven concrete surface. The present application forms a flat rubber strip installation base through the embedded steel plate, and the rubber strip is fixed by being wrapped by the concrete, so that the influence of the construction error on the sealing performance can be reduced.

[0065] Through the above technical solution, the present application solves the problems of easy falling off of the waterproof rubber strip of the first and last ring segment and joint leakage. The steel plate provides a rigid support base for the rubber strip, the anchor bar 40 enhances the stability of the combination of the steel plate and the concrete, and the exposed design of the two ends of the rubber strip ensures that a complete ring-shaped water stop ring is formed when the adjacent segments are assembled. At the same time, the rubber strip is wrapped by the concrete, which can avoid long-term exposure to the external environment and prolong the service life.

[0066] In some embodiments, when the first and last ring segment is formed, the second steel plate 30 is also embedded at the first end of the first and last ring segment, and at least part of the second steel plate 30 protrudes from the first end. The first end is located at one end of the first and last ring segment in a direction perpendicular to the ring direction.

[0067] In the next step, the second steel plate 30 is pre-arranged at the first end of the first and last ring segment, and at least part of the second steel plate 30 protrudes from the first end. The first end is located at one end of the first and last ring segment in a direction perpendicular to the ring direction. The first end is the end of the first and last ring segment that communicates with the two vertical shafts of the starting well and the receiving well. The second steel plate 30 is arranged so that the first and last ring segment can be connected to the support reinforcement structure in the vertical shaft through welding, mechanical connection or other methods to build a more stable connection relationship, thereby further strengthening the structural strength of the first and last ring segment and adapting to the destructive impact of earthquakes on the tunnel support structure in earthquake-prone areas.

[0068] The second steel plate 30 refers to a metal plate-shaped structure embedded at the end of the segment, which can be realized by stamping a steel plate and welding an anchor bar 40. The protruding part is used to connect with the external support structure to enhance the structural strength of the end of the segment.

[0069] In some embodiments, embedding the first steel plate 10 on the outer side of the first and last ring segment and embedding the second steel plate 30 at the first end of the first and last ring segment includes: forming the first steel plate 10 in an arc shape and the second steel plate 30 in a plate shape; welding the anchor bar 40 on the inner side of the first steel plate 10 in the ring direction and the second steel plate 30, and attaching the waterproof rubber strip on the inner side of the first steel plate 10 in the ring direction; installing the first steel plate 10 and the second steel plate 30 into the mold, and pouring and forming the first and last ring segment, so that the first steel plate 10 is located on the outer side of the first and last ring segment in the ring direction, and at least part of the second steel plate 30 protrudes from the first end of the first and last ring segment.

[0070] Specifically, in the first and last ring segment forming process, the first steel plate 10 and the second steel plate 30 are embedded in the concrete. The first steel plate 10 is arranged along the circumferential outer side of the segment, and the second steel plate 30 is fixed to the first end of the segment. The steel plate is connected to the concrete by welding the anchor bar 40. The protruding part of the second steel plate 30 extends to the outside of the segment, and the protruding part can be welded or bolted with the shaft support structure during subsequent construction. Thus, a continuous and rigid connection interface is formed at the joint between the segment end and the support structure, preventing groundwater from penetrating along the joint.

[0071] Compared with the prior art, the prior art does not provide a pre-embedded steel plate structure at the segment end, and the segment and the shaft support structure are only sealed by grouting or ordinary rubber strips, which has insufficient interface connection strength and is prone to leakage. The present application forms a rigid connection interface by embedding the second steel plate 30 to improve the reliability of the end sealing.

[0072] Through the above technical scheme, the present application effectively solves the water seepage problem at the joint between the first and last ring segments and the support structure, improves the connection strength between the segment end and the external structure, forms a stable and rigid sealing interface, and prevents groundwater from penetrating into the tunnel through the joint.

[0073] In some embodiments, when the waterproof rubber strip is attached to the circumferential inner side of the first steel plate 10, the waterproof rubber strip is controlled to be arranged close to the second end; and the second end is arranged away from the first end in the direction perpendicular to the circumferential direction of the first and last ring segments.

[0074] Controlling the waterproof rubber strip to be arranged close to the second end means that the waterproof rubber strip is arranged on the other side edge region of the first and last ring segments away from the first end, which can be achieved by mold positioning or laser calibration, to ensure that the position of the waterproof rubber strip is aligned with the joint of the adjacent segment. At the same time, by arranging the waterproof rubber strip at the second end, the waterproof performance of the waterproof rubber strip itself can be further improved, so that the waterproof rubber strip expands in the rain only when the rain is too abundant and the rainwater can penetrate from the first end to the second end along the axial direction of the tunnel, to prevent further penetration of the rainwater.

[0075] Specifically, in the first and last ring segment forming process, the first steel plate 10 and the second steel plate 30 are fixed in the mold by welding the anchor bar 40, and then the waterproof rubber strip is accurately attached to the position close to the second end on the circumferential inner side of the first steel plate 10. After the grout solidifies, the circumferential outer side of the first steel plate 10 and the first end of the second steel plate 30 of the first and last ring segments are exposed respectively. When the segments are assembled, the waterproof rubber strip is arranged close to the second end, which can cover the weak area of the joint of the adjacent segment, and at the same time avoid misalignment of the rubber strip due to the influence of the exposed steel plate at the first end. Thus, the waterproof rubber strip forms a continuous and closed sealing ring after being aligned in the circumferential direction, effectively blocking the path of groundwater penetrating into the tunnel along the joint.

[0076] By the technical scheme, the waterproof sealing performance of the first and last ring pipe joint can be enhanced, the groundwater infiltration risk can be reduced, the influence of environmental erosion on the service life of the waterproof strip can be reduced by optimizing the arrangement position of the waterproof strip, and the long-term reliability of the tunnel structure can be improved.

[0077] In some embodiments, the second steel plate 30 is welded with the anchor bar 40 in a way of perforation plug welding, so that the anchor bar 40 is arranged through the second steel plate 30 in the thickness direction of the second steel plate 30; after the first and last ring pipe is cast and formed, at least part of the anchor bar 40 is located outside the first and last ring pipe, and the part of the anchor bar 40 located outside the first and last ring pipe is connected with the supporting structure in the shaft.

[0078] The perforation plug welding refers to a process of welding the anchor bar 40 through a through hole formed on the steel plate, which can be realized by carbon dioxide gas shielded welding or arc welding, and the molten metal fills the gap between the through hole and the anchor bar 40 during the welding process to form a through connection. The anchor bar 40 through the second steel plate 30 in the thickness direction refers to that the axis of the anchor bar 40 is perpendicular to the plane of the steel plate, and one end of the anchor bar 40 is embedded in the inside of the concrete pipe after welding, and the other end extends out of the surface of the pipe. The anchor bar 40 connected with the supporting structure refers to that the exposed end of the anchor bar 40 is rigidly fixed with the steel mesh, the concrete structure or the embedded part of the shaft side wall by welding, bolting or pouring.

[0079] Specifically, during the prefabrication of the first and last ring pipe, the second steel plate 30 is pre-processed into a metal plate with regularly arranged through holes, the anchor bar 40 passes through the through hole and is welded with the steel plate on both sides to ensure that a continuous fusion layer is formed between the anchor bar 40 and the steel plate. When the pipe is poured, the steel plate is fixed in the mold, the concrete wraps the inner segment of the anchor bar 40 and the steel plate, and the exposed segment of the anchor bar 40 remains clean for subsequent connection. During construction, after the first and last ring pipe is installed in place, the exposed anchor bar 40 is aligned with the reserved interface of the shaft supporting structure, and the anchoring is completed by lap welding or mechanical fastening to form the force transmission path between the pipe and the shaft.

[0080] In this step, by controlling the anchor bar 40 to be welded with the second steel plate 30 in a way of perforation plug welding, the anchor bar 40 welded with the second steel bar at the two ends of the tunnel can extend into the shaft after the first and last ring pipe is installed, at this time, the construction personnel can further fix the first and last ring pipe by welding the part of the anchor bar 40 extending into the shaft with the supporting steel structure in the shaft, so as to further improve the structural strength of the first and last ring pipe to adapt to the environment of the frequent earthquake belt.

[0081] In some embodiments, the bearing capacity of a single anchor bar 40 welded with the second steel plate 30 is calculated by the following formula:

[0082] ;

[0083] Where C is the bearing capacity of a single anchor bar, d is the diameter of the anchor bar, σ is the tensile strength of the anchor material, and S is the safety factor, ranging from 1.5 to 3.0.

[0084] The diameter of the anchor bar 40 refers to the transverse dimension of the circular cross-section anchor bar 40. Specifically, it can be achieved by using steel bars with a diameter of 8 mm to 20 mm. This parameter directly affects the cross-sectional area and bearing capacity of the anchor bar 40. The tensile strength of the anchor bar 40 material refers to the maximum stress value that the material can withstand under tension. Specifically, it can be achieved by using low-carbon alloy steel with a tensile strength of 400 MPa to 600 MPa. Its value is determined by the physical properties of the material itself. The safety factor refers to the ratio between the design bearing capacity and the actual working load. Specifically, a value range of 1.5 to 3.0 can be used to cover the safety redundancy requirements under different working conditions. For example, a higher safety factor can be used in dynamic load or earthquake-prone areas.

[0085] Specifically, during the manufacturing process of the first and final ring segments, the load-bearing capacity of the anchor bars 40 connected to the second steel plate 30 is verified using the aforementioned formula, based on the design load requirements of the tunnel project. Determining the diameter and number of the anchor bars 40 using this calculation ensures that the anchor bars 40 can withstand external loads during segment assembly and subsequent use, preventing loosening or displacement of the segment connection due to anchor bar 40 failure, thereby maintaining the stability between the first and final ring segments and the supporting structure.

[0086] Compared with existing technologies, traditional methods often rely on empirical experience to select anchor bar 40 specifications, lacking a quantitative calculation basis. This can easily lead to insufficient bearing capacity or excessive redundancy of anchor bar 40. This solution, by introducing a bearing capacity calculation formula, establishes a clear mathematical relationship between anchor bar 40 diameter, material strength, and safety factor. This provides a scientific basis for anchor bar 40 selection, ensuring structural safety while optimizing material usage.

[0087] Through the above-mentioned technical solution, this application can accurately match the specifications of the anchor bar 40 with the actual project requirements, preventing segment connection failure caused by insufficient anchor bar 40 strength, and thus avoiding the degradation of the sealing performance of the waterstop strip 20 caused by segment misalignment. At the same time, through the appropriate setting of the safety factor, the anchor bar 40 design can adapt to the high dynamic load environment of frequent seismic zones, improving the long-term reliability of the tunnel structure.

[0088] In these embodiments of the present application, statistics on the historical occurrence of earthquakes in the construction area can be collected to determine the maximum level of earthquakes in the area and the maximum value of the force exerted on the tunnel support structure due to the earthquake. At this time, the minimum number of required anchor bars 40 can be calculated using the above formula to adapt to the impact of the environment of the high-frequency earthquake zone on the tunnel structure.

[0089] In some embodiments, the anchor bars 40 welded to the first steel plate 10 and the anchor bars 40 welded to the second steel plate 30 are arranged in staggered positions in the direction perpendicular to the circumferential direction of the first and last ring segments.

[0090] This step aims to reduce the risk of concrete weakening caused by the position conflict of the anchor bars 40 of the first steel plate 10 and the second steel plate 30. This step can be performed after determining the size parameters of the single segment in step S1 to design the positions of the anchor bars 40 of the first steel plate 10 and the second steel plate 30 in the direction perpendicular to the circumferential direction. For example, in some embodiments, the anchor bars 40 of the first steel plate 10 can be arranged equidistantly along the circumferential direction, and the anchor bars 40 of the second steel plate 30 can be arranged with an offset of 50-100 mm to ensure that the concrete is dense and free of voids during grouting, thereby improving the overall strength and seismic performance of the first and last ring segments.

[0091] In some embodiments, after the first and last ring segments are formed by grouting, the portions of the first steel plate 10 that protrude outward from the circumferential direction of the first and last ring segments and the portions of the second steel plate 30 that protrude outward from the first end are coated with anticorrosive paint to form an anticorrosive paint layer, and the thickness of the anticorrosive paint layer is controlled to be not less than 50 μm.

[0092] The anticorrosive paint layer can be a protective layer attached to the surface of the steel plate to prevent oxidation of the metal, and can be implemented using epoxy resin paint or polyurethane paint. Such paint has high adhesion and corrosion resistance, and can effectively isolate water vapor and oxygen from contacting the surface of the steel plate. The thickness of not less than 50 μm refers to the average coverage thickness of the anticorrosive paint layer, which can be achieved by applying the paint in multiple stages or by spraying.

[0093] Specifically, after the first and last ring segments are completed by grouting, the exposed portions of the first steel plate 10 and the second steel plate 30 that protrude outward need to be surface treated, such as removing floating slurry and impurities, and then applying anticorrosive paint using rolling or spraying methods. The uniformity of the coating needs to be controlled during the coating process, and the coating is applied in stages to achieve the target thickness. By covering the anticorrosive layer, the corrosion of the steel plate caused by groundwater erosion or environmental exposure can be slowed down, and the sealing failure of the segment connection caused by metal corrosion can be avoided.

[0094] In some specific embodiments, the anticorrosive paint can be applied after the segment is demolded, for example, using a high-pressure airless spraying device to apply the paint in two stages, with each coating thickness controlled to be between 25 μm and 30 μm, and the interval time between the two coatings adjusted according to the curing characteristics of the paint.

[0095] Compared with the prior art, the exposed portions of the steel plates of the first and last ring segments are not treated with anticorrosive paint in traditional construction, which makes the steel plates prone to corrosion by groundwater or environmental media, thereby causing problems such as anchor bar corrosion and accelerated aging of the waterproof rubber strip. The present scheme improves the stability of the sealing system from the perspective of structural durability by adding an anticorrosive layer.

[0096] By the technical scheme, the corrosion risk of the first and last ring pipe exposed steel structure is significantly reduced, the long-term stability of the ring-shaped water stop ring and the end sealing structure is maintained, and the underground water infiltration problem can be effectively prevented during the tunnel construction period and the operation period.

[0097] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like made under the inventive concept of the present application, using the contents of the present application specification and drawings, are included in the patent protection scope of the present application.

Claims

1. A large diameter slurry shield method for a multi-frequency earthquake zone, characterized in that: The steps include: Obtain tunnel size parameters and determine the size parameters of individual segments based on the tunnel size parameters; Pre-setting the first and last ring segments, when forming the first and last ring segments, pre-embed a first steel plate on the circumferential outer side of the first and last ring segments, and set a water-stop strip on the circumferential inner side of the first steel plate close to the first and last ring segments; pre-embed a second steel plate at the first end of the first and last ring segments, at least a portion of the second steel plate protrudes from the first end, and the first end is located at one end of the first and last ring segments in a direction perpendicular to the circumferential direction; in a direction perpendicular to the circumferential direction of the first and last ring segments, the anchor bars welded to the first steel plate and the anchor bars welded to the second steel plate are staggered; Assembling a shield machine and adjusting the parameters of the shield machine, and controlling the shield machine to stop when it excavates to the first and last ring positions of the tunnel; Install the first and last ring segments, and control the circumferential direction of the tunnel so that the first steel plates in adjacent first and last ring segments are aligned in the circumferential direction, and the waterstop strips are aligned in the circumferential direction to form a circumferential waterstop ring; Shield tunneling is continued, and grouting is simultaneously performed between the installed pipe segments and the soil to stabilize the surrounding soil. After the first and last ring segments are grouted and formed, an anti-corrosion coating is applied to the portion of the first steel plate protruding from the circumferential outer side of the first and last ring segments and the portion of the second steel plate protruding from the first end to form an anti-corrosion coating layer. The thickness of the anti-corrosion coating layer is controlled to be no less than 50 μm. The method of pre-embedding a first steel plate on the circumferential outer side of the first and last ring segments and pre-embedding a second steel plate at the first end of the first and last ring segments comprises: A first steel plate formed into an arc shape and a second steel plate formed into a plate shape; Welding anchor bars on the circumferential inner side of the first steel plate and the second steel plate, and attaching waterproof adhesive strips on the circumferential inner side of the first steel plate; Installing the first steel plate and the second steel plate into a mold, and grouting to form the first and last ring segments, so that the first steel plate is located circumferentially outside the first and last ring segments, and at least a portion of the second steel plate protrudes from the first end of the first and last ring segments; The load-bearing capacity of a single anchor bar welded to the second steel plate is calculated using the following formula: Where C is the bearing capacity of a single anchor bar, d is the diameter of the anchor bar, σ is the tensile strength of the anchor material, and S is the safety factor, ranging from 1.5 to 3.

0.

2. The large-diameter slurry shield method for multiple-frequency earthquake zones according to claim 1 is characterized in that: The first steel plate embedded in the outer side of the first and last ring segments includes: forming a first steel plate into an arc shape, and welding anchor bars on the inner side of the first steel plate; Installing a waterproof rubber strip, and controlling the waterproof rubber strip to be arranged along the circumferential direction of the first steel plate; Grouting forming: install the first steel plate welded with anchor bars and equipped with waterproof strips into the mold, and grouting is performed to form the first and last ring segments after the slurry solidifies and forms the segments. Along the circumferential direction of the first and last ring segments, it is necessary to control the two ends of the waterproof strips to be exposed.

3. The large-diameter slurry shield method for a multi-frequency earthquake zone according to claim 2, characterized in that: In the step of attaching the waterproof rubber strip, the waterproof rubber strip is attached to the inner side of the first steel plate.

4. The large-diameter slurry shield method for multiple-frequency earthquake zones according to claim 1, characterized in that: When the waterproof rubber strip is attached to the inner side of the first steel plate, the waterproof rubber strip is controlled to be disposed close to the second end; The second end is arranged on the first and last ring segments away from the first end along a direction perpendicular to the circumferential direction.

5. The large-diameter slurry shield method for multiple-frequency earthquake zones according to claim 1, characterized in that: When welding the anchor bar to the second steel plate, a perforation plug welding method is adopted, so that the anchor bar is arranged through the second steel plate along the thickness direction of the second steel plate; After the first and last ring segments are cast and formed, at least part of the anchor bars are located outside the first and last ring segments, and the part of the anchor bars located outside the first and last ring segments is connected to the support structure in the shaft.

Images