Large-diameter slurry shield method for multi-frequency seismic zone

Abstract

The invention discloses a multi-frequency seismic zone large-diameter slurry shield method which comprises the following steps: S1, obtaining tunnel size parameters, and determining size parameters of a single segment according to the tunnel size parameters; s2, pre-arranging first and tail ring segments, when the first and tail ring segments are formed, pre-burying a first steel plate on the annular outer side of the first and tail ring segments, and arranging a water stop rubber strip on the annular inner side, close to the first and tail ring segments, of the first steel plate; s3, a shield tunneling machine is assembled, parameters of the shield tunneling machine are adjusted, and the shield tunneling machine is controlled to stop when tunneling to the head ring position and the tail ring position of the tunnel; s4, the first ring pipe pieces and the tail ring pipe pieces are installed, the first steel plates in the adjacent first ring pipe pieces and the adjacent tail ring pipe pieces are controlled to be aligned in the annular direction of the tunnel, the water stop rubber strips are controlled to be aligned in the annular direction, and annular water stop rings are formed; and S5, shield tunneling continues, and grouting is synchronously conducted between the installed pipe segments and the soil body so as to stabilize the peripheral soil body. According to the technical scheme, the waterproof sealing performance during tunnel shield construction and after a tunnel is completed is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel engineering, in particular to a large-diameter slurry shield method in a multi-frequency earthquake zone. Background Art

[0002] In shield tunneling, the waterproof seal of the first and last ring segments is closely linked to the overall reliability of the tunnel. At the two ends of the tunnel (where the first and last ring segments are installed), the structure is open and connected to the vertical shaft. Inadequate waterproof seals can allow groundwater to penetrate the tunnel, directly affecting construction safety and progress, and adversely impacting the overall project.

[0003] During the shield tunneling process of related technologies, no special structural requirements are put forward for the first and last ring segments. As a result, if heavy rain or extreme weather occurs during the construction phase, groundwater can easily penetrate into the tunnel through both ends of the tunnel. At the same time, as time goes by, the waterproof strips arranged at the first and last ring segments in the related technologies are exposed to the external environment for a long time, which causes the service life of the waterproof strips to be rapidly shortened, and then the waterproof sealing performance is reduced during the use phase after the completion of the 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 tunnel is completed has become a difficult problem that needs to be solved urgently in the industry. Summary of the Invention

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

[0006] To achieve the above-mentioned purpose, the present invention proposes a large-diameter slurry shield method for a multi-frequency seismic zone, which includes the following steps: step S1, obtaining tunnel size parameters, and determining the size parameters of a single segment according to the tunnel size parameters; step S2, pre-setting the first and last ring segments, and when forming the first and last ring segments, pre-embedding the first steel plate on the circumferential outer side of the first and last ring segments, and setting a waterstop strip on the circumferential inner side of the first steel plate close to the first and last ring segments; step S3, assembling the shield machine and adjusting the shield machine parameters, and controlling the shield machine to stop when it excavates to the first and last ring positions of the tunnel; step S4, installing the first and last ring segments, and controlling the first steel plates in each adjacent first and last ring segments to be circumferentially aligned along the circumference of the tunnel, and the waterstop strips to be circumferentially aligned to form an annular waterstop ring; step S5, continuing the shield excavation, and synchronously grouting between the installed segments and the soil to stabilize the surrounding soil.

[0007] In some embodiments, in step S2, embedding the first steel plate on the circumferential outer side of the first and last segment rings includes the following sub-steps: Step S21, forming the first steel plate into an arc shape and welding anchor bars on the circumferential inner side of the first steel plate; Step S22, mounting a waterproof rubber strip and controlling the waterproof rubber strip to be arranged along the circumferential direction of the first steel plate; Step S23, grouting and forming. Install the first steel plate welded with anchor bars and with the waterproof rubber strip mounted into the mold, and grout. After the slurry solidifies and forms the first and last segment rings, wherein, along the circumferential direction of the first and last segment rings, it is necessary to control both ends of the waterproof rubber strip to be exposed.

[0008] In some embodiments, when mounting the waterproof rubber strip, the waterproof rubber strip is mounted on the circumferential inner side of the first steel plate.

[0009] In some embodiments, when forming the first and last segment rings, it further includes embedding a second steel plate at the first end of the first and last segment rings, and at least a part of the second steel plate protrudes from the first end; the first end is at one end of the first and last segment rings along the direction perpendicular to the circumferential direction.

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

[0011] In some embodiments, when mounting the waterproof rubber strip on the circumferential inner side of the first steel plate, control the waterproof rubber strip to be arranged close to the second end; the second end is arranged away from the first end along the direction perpendicular to the circumferential direction of the first and last segment rings.

[0012] In some embodiments, when welding the anchor bars to the second steel plate, the penetration plug welding method is adopted, so that the anchor bars penetrate through the second steel plate along the thickness direction of the second steel plate; after the first and last segment rings are poured and formed, at least a part of the anchor bars is located outside the first and last segment rings, and the part of the anchor bars located outside the first and last segment rings is connected to the support structure in the shaft.

[0013] In some embodiments, the bearing capacity of a single anchor bar welded to the second steel plate is calculated by 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 bar material, and S is the safety factor, and the value range is from 1.5 to 3.0.

[0014] In some embodiments, in a direction perpendicular to the circumferential direction of the first and last segment rings, the anchor bars welded to the first steel plate and the anchor bars welded to the second steel plate are arranged in a staggered manner.

[0015] In some embodiments, after the first and last segment rings are grouted and formed, an anticorrosive coating is applied to the part of the first steel plate protruding from the circumferential outer side of the first and last segment rings and the part of the second steel plate protruding from the first end to form an anticorrosive coating layer; the thickness of the anticorrosive coating layer is controlled to be not less than 50 μm.

[0016] The technical solution of the present invention pre-sets the first and last segment rings, embeds the first steel plate on the circumferential outer side of the first and last segment rings, and arranges a water stop rubber strip on the circumferential inner side of the first steel plate close to the first and last segment rings. At the same time, when installing the first and last segment rings, along the circumferential direction of the tunnel, the first steel plates in each adjacent first and last segment rings are aligned circumferentially, and each water stop rubber strip is aligned circumferentially to form a circumferential water stop ring. The water stop expansion performance of the water stop rubber strip can be used to reduce the risk of groundwater continuing to penetrate into the tunnel interior, and the first steel plate can seal the water stop rubber strip on the circumferential inner side of the first and last segment rings, thereby reducing the contact between the water stop rubber strip and the outside world, providing protection for the water stop rubber strip, reducing the aging rate of the water stop rubber strip, and improving the waterproof sealing performance and reliability during the tunnel shield construction and after the tunnel is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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 drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0018] Figure 1 It is a sectional view along the axial direction of the tunnel of the first segment ring in the multi-frequent earthquake zone large-diameter slurry shield method provided by an embodiment of the present invention; Figure 2 It is a flow chart of the multi-frequent earthquake zone large-diameter slurry shield method provided by an embodiment of the present invention; Figure 3 It is a sub-step flow chart of step S2 in the multi-frequent earthquake zone large-diameter slurry shield method provided by an embodiment of the present invention; Figure 4 It is a sub-step flow chart of step S2 in the multi-frequent earthquake zone large-diameter slurry shield method provided by another embodiment of the present invention.

[0019] The realization of the purpose, functional features and advantages of the present invention will be further described in conjunction with the embodiments with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] 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 the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship and movement conditions between components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0023] When carrying out large-diameter slurry shield construction in a multi-frequent earthquake zone, it faces challenges such as frequent seismic activities, poor soil stability, and high risk of water inrush, which are related to construction safety and the long-term durability of the tunnel. In the initial stage of large-diameter slurry shield construction in a multi-frequent earthquake zone, it is usually necessary to optimize the segment design and installation process to enhance the seismic resistance and waterproof performance of the tunnel structure. Traditional methods such as standard segment assembly or simple water-stop measures are prone to problems such as segment dislocation, leakage, or structural failure in the earthquake zone. When using the slurry shield method for tunnel construction, the segment installation, tunneling process, and seismic disturbance will all cause soil deformation and structural damage, resulting in the superposition of multiple risks, leading to tunnel settlement or leakage exceeding the control standard range. Based on this, how to safely and efficiently implement large-diameter slurry shields in a multi-frequent earthquake zone and maintain structural stability and waterproof performance at all stages of construction has become an urgent problem in the industry.

[0024] In shield tunneling, the waterproof seal of the first and last ring segments is closely linked to the overall reliability of the tunnel. At the two ends of the tunnel (where the first and last ring segments are installed), the structure is open and connected to the vertical shaft. Inadequate waterproof seals can allow groundwater to penetrate the tunnel, directly affecting construction safety and progress, and adversely impacting the overall project.

[0025] During the shield tunneling process of related technologies, no special structural requirements are put forward for the first and last ring segments. As a result, if heavy rain or extreme weather occurs during the construction phase, groundwater can easily penetrate into the tunnel through both ends of the tunnel. At the same time, as time goes by, the waterproof strips arranged at the first and last ring segments in the related technologies are exposed to the external environment for a long time, which causes the service life of the waterproof strips to be rapidly shortened, and then the waterproof sealing performance is reduced during the use phase after the completion of the tunnel construction, causing groundwater to penetrate into the tunnel.

[0026] Therefore, addressing the issue of insufficient waterproofing and sealing during tunnel shield construction and after tunnel completion has become a pressing challenge within the industry. Based on this, a large-diameter slurry shield method suitable for use in high-frequency seismic zones has been designed. This method effectively improves the waterproofing and sealing performance and reliability at the tunnel's initial and final ring locations.

[0027] Please refer to Figures 1 to 4 The present invention proposes a large-diameter slurry shield method for a multi-frequency earthquake zone, which includes the following steps: Step S1: Obtain tunnel dimensional parameters and determine individual segment dimensional parameters based on them. In this step, tunnel dimensional parameters (such as tunnel diameter and length) are obtained and used to determine individual segment dimensional parameters (such as width and arc length) to ensure that the segment design matches tunnel requirements.

[0028] When constructing large-diameter tunnels in areas with frequent earthquakes, accurate determination of segment dimensions is the primary step. By obtaining tunnel dimension parameters, individual segments can be rationally designed to adapt to the dynamic loads in the earthquake zone.

[0029] Tunnel dimensional parameters are the fundamental data that determine the geometry of the segments. These parameters, such as tunnel cross-section profiles obtained through laser scanning or geological radar, are used to calculate segment arc length and thickness. The first and last rings of segments are located at the tunnel opening. Their special structural design prevents groundwater from seeping through these openings.

[0030] Step S2, pre-setting the first and last ring segments. When forming the first and last ring segments, pre-embed the first steel plate 10 on the circumferential outer side of the first and last ring segments, and set the water stop strip 20 on the circumferential inner side of the first steel plate 10 close to the first and last ring segments.

[0031] This step is the process of preparing the segment materials before tunnel construction. On the basis of determining the size parameters of a single segment, a first steel plate 10 is pre-embedded on the circumferential outer side of the first and last ring segments, and a waterstop strip 20 is set on the circumferential inner side of the first steel plate 10 close to the first and last ring segments. The pre-embedded 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. At the same time, the first steel plate 10 can also cooperate with the main structure of the first and last ring segments to seal the waterstop strip 20, reduce the exposure of the waterstop strip 20 to the external environment, reduce the aging rate of the waterstop strip 20, and improve reliability.

[0032] In these embodiments of the present application, the first steel plate 10 and the waterproofing strip 20 are pre-embedded in the mold during the formation of the first and last ring segments. After the slurry is placed in the mold, they are integrally formed with the main structure of the first and last ring segments. The purpose of pre-embedding the first steel plate 10 and providing the waterproofing strip 20 is to enhance the tensile strength and waterproof sealing properties of the segments.

[0033] The first steel plate 10 is a rigid support member, specifically a corrosion-resistant alloy steel plate embedded in the outer side of the segment to enhance the structure's deformation resistance. The waterstop strip 20 is specifically made of EPDM rubber and is continuously laid along the inner side of the steel plate to form an elastic sealing layer.

[0034] Step S3: assemble the shield machine and adjust the shield machine parameters, and control the shield machine to stop when it excavates to the first and last ring positions of the tunnel.

[0035] This step involves the shield machine excavating. Assembling the shield machine and adjusting its parameters involves moving the various components into the launch shaft, assembling them, and adjusting parameters such as thrust and slurry pressure. The machine stops when it reaches the first ring to assemble the first ring of tunnel segments. Adjusting shield machine parameters requires considering the soil characteristics in seismic zones to ensure stable excavation.

[0036] As the tunnel is constructed, the shield machine stops when it reaches the last ring of the tunnel to assemble the last ring of the cableway segments.

[0037] Step S4: Install the first and last ring segments and control the circumferential alignment of the first steel plates 10 and the water stop strips 20 in adjacent first and last ring segments along the circumferential direction of the tunnel to form a circumferential water stop ring.

[0038] This step is the installation of the segments. After the shield machine completes the first ring position, the first ring segments are installed at the first ring position to form a ring-shaped support structure. It can be understood that the construction workers need to splice the first ring segments in sequence along the circumference to form a ring-shaped support structure.

[0039] In this step, the first steel plates 10 in each adjacent first and last segment rings are aligned circumferentially, and the sealing rubber strips 20 are aligned circumferentially to form a circumferential water stop ring. That is, in the step of pre-setting the first and last segment rings in step S2, the first steel plates 10 and the sealing rubber strips 20 are pre-arranged circumferentially along the segments, and both ends of the first steel plates 10 and the sealing rubber strips 20 in the circumferential direction are exposed outside the segments. In this way, when the segment assembly step in this step is carried out, only the exposed first steel plates 10 and sealing rubber strips 20 of each segment need to be spliced to achieve the circumferential alignment of the first steel plates 10 in each adjacent first and last segment rings, the circumferential alignment of the sealing rubber strips 20, and the formation of a circumferential water stop ring.

[0040] After the first segment ring is assembled (only the first segment ring is described as an example in this application, and the last segment ring is similar and will not be elaborated), a circumferential water stop ring can be formed. When groundwater infiltrates into the first segment ring, the sealing rubber strip 20 will expand when it meets water to fill the gaps and holes inside the first segment ring and at the joints of adjacent first segment rings, thereby achieving the effect of controlling water with water and preventing water from continuing to spread into the tunnel formed by the segments.

[0041] It should be noted that ordinary segments are also provided with corresponding water stop tape structures, and the materials and structures of the segment mechanism itself also consider the influence of groundwater leakage. That is, ordinary segments themselves have a certain ability to prevent groundwater leakage. In these embodiments of this application, the circumferential water stop ring formed by the sealing rubber strip 20 is mainly intended to alleviate the leakage of groundwater along the axial direction of the tunnel (the shield direction of the shield machine). The reason is that at the positions of the first and last segment rings, they are usually the positions where the tunnel communicates with the launch shaft and the receiving shaft. Therefore, along the axial direction of the tunnel, one end of the first and last segment rings is an open structure, and the other end is a structure for assembling with ordinary segments. At this time, in the initial stage of tunnel construction, when there is abundant external rainwater, the water flow is likely to penetrate along the axial direction of the tunnel in the segments. Therefore, it is necessary to set the aforementioned circumferential water stop ring structure at the positions of the first and last segment rings to alleviate this water flow penetration and further improve the waterproof performance of the tunnel during construction and subsequent use.

[0042] In these embodiments of this application, the sealing rubber strip 20 is arranged on the circumferential inner side of the first steel plate 10 close to the first and last segment rings, that is, the sealing 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 sealing rubber strip 20 expanding prematurely due to being eroded by ordinary groundwater, and thus alleviate the risk of rainwater penetrating along the axial direction of the tunnel when there is more abundant rainwater, thereby improving the waterproof sealing performance during tunnel shield construction and after the tunnel is completed.

[0043] Step S5: Continue shield tunneling and simultaneously grout between the installed segment sections and the soil to stabilize the surrounding soil.

[0044] The main feature of this method lies in strengthening the waterproof design of the segment structure (such as embedding the first steel plate 10) and the waterstop rubber strip 20 according to the characteristics of the seismic zone, and achieving deformation control through circumferential alignment and synchronous grouting. Compared with the prior art, this method can more effectively resist seismic disturbances and reduce the risks of leakage and settlement.

[0045] According to the large-diameter slurry shield method in a multi-frequent seismic zone provided by the embodiments of the present application, the traditional method relies on a single waterstop rubber strip and does not form a continuous sealing structure. This solution constructs a dual waterproof system through the synergistic effect of the embedded steel plate and the rubber strip. The steel plate provides rigid support to prevent excessive compression of the rubber strip, and the rubber strip compensates for the gap caused by the installation error of the steel plate. The circumferential alignment design ensures the continuous closure of the waterproof structure in the circumferential direction, avoiding weak points of leakage. Synchronous grouting not only reinforces the soil, but also forms a secondary waterproof barrier around the segment, effectively blocking the groundwater seepage path.

[0046] Through the above technical solutions, the present application solves the groundwater seepage risk in the first and last ring segment areas and forms a multi-level waterproof system. The combined design of the rigid steel plate and the elastic rubber strip improves the durability of the sealing structure. The circumferential alignment process ensures the continuity of the waterproof interface, and the synchronous grouting reinforcement enhances the soil stability. This solution significantly reduces the incidence of leakage accidents during construction, extends the service life of the tunnel, and is particularly suitable for large-diameter tunnel projects in seismically active areas.

[0047] In some embodiments, in step S2, embedding the first steel plate 10 on the circumferential outer side of the first and last ring segments includes the following sub-steps: Step S21, forming the first steel plate 10 into an arc shape and welding anchor bars 40 on the circumferential inner side of the first steel plate 10.

[0048] The arc-shaped first steel plate 10 refers to a curved metal plate that matches the circumferential shape of the tunnel. Specifically, it can be formed by a rolling process, and its radian radius can be 1.05 to 1.2 times the design radius of the tunnel. This structure can adapt to the circumferential outer contour of the segment and improve the bonding tightness between the steel plate and the concrete.

[0049] The anchor bar 40 refers to a metal reinforcement member welded to the inner side of the steel plate. Specifically, it can be a deformed bar or a round bar, such as a steel bar with a diameter of 8 to 12 mm, and is fixed to the steel plate surface by arc welding. The anchor bar 40 can enhance the mechanical biting force between the steel plate and the concrete and prevent the steel plate from shifting during the grouting process.

[0050] Step S22, installing the waterstop rubber strip and controlling the circumferential arrangement of the waterstop rubber strip along the first steel plate 10. Further, in these embodiments of the present application, in the step of installing the waterstop rubber strip, the waterstop rubber strip is installed on the circumferential inner side of the first steel plate 10.

[0051] The circumferential inward direction refers to the direction along the inner surface of the segment's curved profile. This can be achieved by providing a rubber strip mounting groove on the inner curved surface of the steel plate, thereby ensuring a tight fit between the rubber strip and the steel plate. The application of waterproof rubber strips refers to the fixing of flexible sealing material to the surface of the steel plate, specifically by using adhesives or mechanical clips, so that the rubber strip forms a continuous sealing interface with the contact surface of adjacent segments during segment assembly.

[0052] Specifically, during the manufacturing phase of the first and final ring segments, the first steel plate 10 is pre-embedded on the outer circumferential surface of the segment, while the waterproof rubber strip is fixed to the inner curved surface of the steel plate. During segment assembly, the rubber strips on the inner curved surfaces of the steel plates of adjacent segments squeeze against each other, forming a continuous waterstop along the circumference of the tunnel. Because the rubber strip is encased inside the steel plate, it is protected from direct exposure to the external water and soil environment, thereby reducing external mechanical damage and chemical erosion.

[0053] Compared with existing technologies, traditional methods place waterproofing strips directly on the outer surface of the segments. This exposes the strips to corrosive substances in groundwater or soil over a long period of time, leading to accelerated material aging. This solution embeds the strips between the steel plates and concrete, creating a physical barrier to isolate the external environment. At the same time, the strips still provide an effective seal during assembly through contact pressure between the steel plates.

[0054] Step S23, grouting and forming, install the first steel plate 10 welded with anchor bars 40 and with waterproof strips attached into the mold, and grouting to form the first and last ring segments after the slurry solidifies and forms the first and last ring segments. Among them, along the circumferential direction of the first and last ring segments, it is necessary to control the exposure of the two ends of the waterproof strips.

[0055] The present application further proposes forming a first steel plate 10 into an arc shape, and welding anchor bars 40 on the inner side of the first steel plate 10 in the circumferential direction; attaching waterproof strips, and controlling the waterproof strips to be arranged along the circumferential direction of the first steel plate 10; grouting and forming, installing the first steel plate 10 welded with anchor bars 40 and with the waterproof strips attached into a mold, and grouting to form the first and last ring segments after the slurry solidifies and forms, wherein, 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.

[0056] The exposed ends of the waterproof strips refer to the strips extending out of the concrete surface at both ends of the circumference. For example, the exposed length of each end can be 10 to 20 mm. The exposed strips form a continuous sealing interface when adjacent segments are assembled, preventing leakage at the joints. Specifically, during the fabrication of the first and last ring segments, the curved steel plates are first machined to a predetermined curvature and then welded with anchor bars 40. Then, waterproofing strips are affixed along the inner side of the steel plate ring. During grouting, the steel plates are secured within the mold, while concrete envelops the anchor bars 40 and covers the inner area of the steel plate, leaving the ends of the strips exposed. After the segments are demolded, the steel plates are embedded in the concrete ring, with the ends of the strips forming a continuous sealing surface that can be connected to other segment strips.

[0057] Compared with the prior art, traditional segment linings usually only have a waterproof layer on the concrete surface, and the rubber strips are directly pasted at the concrete joints. It is easy for the rubber strips to fall off or the sealing to fail due to the uneven concrete surface. In this solution, a flat base surface for installing the rubber strips is formed by embedding steel plates, and the rubber strips are wrapped and fixed by concrete, which can reduce the influence of construction errors on the sealing performance.

[0058] Through the above technical solution, the present application solves the problems of easy falling off of the waterproof rubber strips at the first and last segment linings and leakage at the joints. The steel plates provide a rigid support base surface for the rubber strips, and the anchor bars 40 enhance the bonding stability between the steel plates and the concrete. The exposed design at both ends of the rubber strips ensures the formation of a complete circumferential water-stop ring when adjacent segment linings are assembled. At the same time, the rubber strips being wrapped by concrete can avoid long-term exposure to the external environment and extend their service life.

[0059] In some embodiments, when forming the first and last segment linings, it further includes embedding a second steel plate 30 at the first end of the first and last segment linings, and at least part of the second steel plate 30 protrudes from the first end; the first end is at one end of the first and last segment linings along the direction perpendicular to the circumferential direction.

[0060] In this sub-step, by pre-arranging the second steel plate 30 at the first end of the first and last segment linings, and at least part of the second steel plate 30 protrudes from the first segment, the first end is at one end of the first and last segment linings along the direction perpendicular to the circumferential direction. It means that the first end is the end where the first and last segment linings are connected to the two shafts of the launch shaft or the receiving shaft. The setting of the second steel plate 30 enables the first and last segment linings to build a more stable connection relationship with the support steel bar structure in the shaft through welding, mechanical connection, etc., so as to further strengthen the structural strength of the first and last segment linings and adapt to the possible destructive impact on the tunnel support structure in earthquake-prone areas.

[0061] The second steel plate 30 refers to a metal plate-like structure embedded at the end of the segment lining. Specifically, it can be realized by stamping a steel plate and then welding the anchor bars 40. The protruding part is used to connect with the external support structure to enhance the structural strength of the segment lining end.

[0062] In some embodiments, embedding the first steel plate 10 on the circumferential outer side of the first and last segment linings and embedding the second steel plate 30 at the first end of the first and last segment linings includes: forming the arc-shaped first steel plate 10 and the plate-shaped second steel plate 30; welding the anchor bars 40 on the circumferential inner side of the first steel plate 10 and the second steel plate 30, and pasting the waterproof rubber strip on the circumferential inner side of the first steel plate 10; installing the first steel plate 10 and the second steel plate 30 into the mold, and grouting to form the first and last segment linings, so that the first steel plate 10 is located on the circumferential outer side of the first and last segment linings, and at least part of the second steel plate 30 protrudes from the first end of the first and last segment linings.

[0063] Specifically, during the forming process of the first and last segment rings, the first steel plate 10 and the second steel plate 30 are embedded inside the concrete. The first steel plate 10 is arranged on the outer side of the segment ring in the circumferential direction, and the second steel plate 30 is fixed to the first end of the segment. By welding the anchor bars 40, a reliable connection is formed between the steel plate and the concrete. The protruding part of the second steel plate 30 extends to the outside of the segment, and during subsequent construction, this protruding part can be welded or bolted to the shaft support structure. Thus, a continuous rigid connection interface is formed at the joint between the segment end and the support structure, preventing groundwater from seeping along the joint.

[0064] Compared with the prior art, the prior art does not provide a pre-embedded steel plate structure at the segment end. The segment and the shaft support structure are only sealed by grouting or ordinary rubber strips, resulting in insufficient interface connection strength and prone to leakage. This solution forms a rigid connection interface by pre-embedding the second steel plate 30, improving the reliability of the end seal.

[0065] Through the above technical solution, this application effectively solves the problem of water seepage at the connection between the first and last segment rings of the tunnel and the support structure, improves the connection strength between the segment end and the external structure, forms a stable rigid sealing interface, and prevents groundwater from seeping into the tunnel through the joint.

[0066] In some embodiments, when installing a waterproof rubber strip on the inner side of the first steel plate 10 in the circumferential direction, the waterproof rubber strip is controlled to be arranged close to the second end; the second end is arranged away from the first end in the direction perpendicular to the circumferential direction of the first and last segment rings.

[0067] Controlling the waterproof rubber strip to be arranged close to the second end means arranging the waterproof rubber strip in the other edge area of the first and last segment rings far from the first end. Specifically, it can be achieved by die positioning or laser calibration to ensure that the position of the waterproof rubber strip aligns with the joint of the adjacent segments. At the same time, setting the waterproof rubber strip at the second end can also further improve the waterproof performance of the waterproof rubber strip itself. 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, the waterproof rubber strip expands due to the rainwater to prevent further penetration of the rainwater.

[0068] Specifically, during the forming process of the first and last segment rings, the first steel plate 10 and the second steel plate 30 are fixed in the mold by welding the anchor bars 40. Subsequently, a waterproof rubber strip is precisely installed on the inner side of the first steel plate 10 close to the second end in the circumferential direction. After the grouting solidifies, the outer side of the first steel plate 10 of the first and last segment rings and the first end of the second steel plate 30 are respectively exposed. When the segments are assembled, since the waterproof rubber strip is arranged close to the second end, it can cover the weak area of the joint between the adjacent segments and avoid the displacement of the rubber strip caused by the influence of the exposed steel plate at the first end. Thus, the waterproof rubber strip forms a continuous and closed sealing ring after circumferential alignment, effectively blocking the path of groundwater seeping into the tunnel along the joint.

[0069] Through the above technical solution, the present application can enhance the waterproof and sealing performance at the joints of the first and last segment rings, reduce the risk of groundwater seepage, and at the same time reduce the impact of environmental erosion on its service life by optimizing the arrangement position of the waterproof rubber strip, thereby improving the long-term reliability of the tunnel structure.

[0070] In some embodiments, when the second steel plate 30 is welded to the anchor bars 40, the method of plug welding through holes is adopted, so that the anchor bars 40 penetrate through the second steel plate 30 along the thickness direction of the second steel plate 30; after the first and last segment rings are poured and formed, at least part of the anchor bars 40 is located outside the first and last segment rings, and the part of the anchor bars 40 located outside the first and last segment rings is connected to the support structure in the shaft.

[0071] Plug welding through holes refers to a process in which the anchor bars 40 are penetrated through the through holes after opening through holes in the steel plate, and specifically can be realized by carbon dioxide gas shielded welding or arc welding. During the welding process, the molten metal fills the gap between the through holes and the anchor bars 40 to form a through connection. The anchor bars 40 penetrating through the second steel plate 30 along the thickness direction means that the axis of the anchor bars 40 is perpendicular to the plane of the steel plate. After welding, one end of the anchor bars 40 is embedded inside the concrete segment, and the other end extends out of the outer surface of the segment. The connection between the anchor bars 40 and the support structure means that the exposed ends of the anchor bars 40 are rigidly fixed to the steel bar mesh, concrete structure or embedded parts on the side wall of the shaft by welding, bolts or pouring.

[0072] Specifically, in the prefabrication stage of the first and last segment rings, the second steel plate 30 is pre-processed into a metal plate with regularly arranged through holes. After the anchor bars 40 pass through the through holes, double-sided welding is performed with the steel plate to ensure the formation of a continuous fusion layer between the anchor bars 40 and the steel plate. During the segment pouring, the steel plate is fixed in the mold, and the concrete wraps the inner section of the anchor bars 40 and the steel plate, and the exposed section of the anchor bars 40 is kept clean for subsequent connection. During construction, after the first and last segment rings are installed in place, the exposed anchor bars 40 are aligned with the reserved interfaces of the shaft support structure, and lap welding or mechanical fastening methods are used to complete the anchoring, forming a force transmission path between the segment and the shaft.

[0073] In this step, by controlling the method of plug welding through holes for the anchor bars 40 during the welding of the second steel plate 30, after the first and last segment rings are installed, at both ends of the tunnel, the anchor bars 40 welded to the second steel bars can extend into the shaft. At this time, the construction personnel can further fix the first and last segment rings by welding the part of the anchor bars 40 extending into the shaft to the support steel bar structure in the shaft, thereby further improving the structural strength of the first and last segment rings to adapt to the environment in earthquake-prone areas.

[0074] In some embodiments, the bearing capacity of a single anchor bar 40 welded to the second steel plate 30 is calculated by the following formula: ; Among them, 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 bar material, and S is the safety factor, with a value range of 1.5 to 3.0.

[0075] The diameter of the anchor bar 40 refers to the transverse dimension of the circular-section anchor bar 40. Specifically, steel bars with a diameter of 8 mm to 20 mm can be used to achieve it. 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 in the tensile state. Specifically, low-carbon alloy steel with a tensile strength of 400 MPa to 600 MPa can be used to achieve it, and its value is determined by the physical properties of the material itself. The safety factor refers to the ratio between the designed 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 areas with dynamic loads or frequent earthquakes.

[0076] Specifically, during the manufacturing process of the first and last ring segments, according to the design load requirements of the tunnel project, the bearing capacity of the anchor bar 40 connected to the second steel plate 30 is checked through the above formula. After determining the diameter and quantity of the anchor bar 40 through this calculation method, it can be ensured that the anchor bar 40 can withstand external loads during the segment assembly and subsequent use stages, avoiding loosening or displacement of the segment connection caused by the failure of the anchor bar 40, thereby maintaining the stability between the first and last ring segments and the support structure.

[0077] Compared with the prior art, in the traditional method, the specifications of the anchor bar 40 are usually selected based on experience, lacking a quantitative calculation basis, which easily leads to insufficient bearing capacity or excessive redundancy of the anchor bar 40. In this solution, by introducing the bearing capacity calculation formula, a clear mathematical relationship is formed among the diameter of the anchor bar 40, the material strength, and the safety factor, making the selection of the anchor bar 40 have a scientific basis and optimizing the material usage while ensuring the structural safety.

[0078] Through the above technical solution, the present application can accurately match the specifications of the anchor bar 40 with the actual engineering requirements, prevent the failure of the segment connection caused by insufficient strength of the anchor bar 40, and further avoid the decline in the sealing performance of the water stop rubber strip 20 caused by segment misalignment. At the same time, through the reasonable setting of the safety factor, the design of the anchor bar 40 can adapt to the high dynamic load environment in earthquake-prone areas, improving the long-term reliability of the tunnel structure.

[0079] In these embodiments of the present application, the historical earthquake occurrence situation in the construction area can be statistically analyzed to judge the maximum earthquake magnitude in this area and the maximum value of the force exerted on the tunnel support structure due to earthquakes. At this time, the minimum quantity of the required anchor bar 40 can be calculated through the above formula to adapt to the influence of the environment in the earthquake-prone area on the tunnel structure.

[0080] In some embodiments, in a direction perpendicular to the circumferential direction of the first and last segment rings, 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 a staggered manner.

[0081] This step aims to reduce the risk of concrete weakening caused by the conflict in the positions of the anchor bars 40 of the first steel plate 10 and the second steel plate 30. This step can design the positions of the anchor bars 40 of the first steel plate 10 and the second steel plate 30 in a direction perpendicular to the circumferential direction after the size parameters of a single segment are determined in step S1. Exemplarily, in some embodiments, the anchor bars 40 of the first steel plate 10 can be arranged at equal circumferential intervals, and the anchor bars 40 of the second steel plate 30 are offset by 50 mm to 100 mm, so as to ensure that the concrete is dense and void-free during grouting, and improve the overall strength and seismic performance of the first and last segment rings.

[0082] In some embodiments, after the first and last segment rings are grouted and formed, an anti-corrosion coating is applied to the part of the first steel plate 10 protruding from the circumferential outer side of the first and last segment rings and the part of the second steel plate 30 protruding from the first end to form an anti-corrosion coating layer; the thickness of the anti-corrosion coating layer is controlled to be not less than 50 μm.

[0083] The anti-corrosion coating layer can be a protective layer attached to the surface of the steel plate to prevent metal oxidation, and specifically, an epoxy resin coating or a polyurethane coating can be used to achieve this. Such coatings have high adhesion and corrosion resistance, and can effectively isolate water vapor and oxygen from contacting the surface of the steel plate. Among them, the thickness not less than 50 μm refers to the average covering thickness of the anti-corrosion coating, and specifically, it can be achieved by the process of applying the coating in multiple layers or by spraying. This thickness range can ensure the anti-corrosion performance while avoiding material waste.

[0084] Specifically, after the first and last segment rings are grouted, the protruding parts of the exposed first steel plate 10 and the second steel plate 30 need to be surface-treated, such as removing floating slurry and impurities, and then the anti-corrosion coating is applied by rolling or spraying. During the coating process, the uniformity of the coating needs to be controlled, and the construction is carried out in stages to reach the target thickness. By covering the anti-corrosion layer, the rusting of the steel plate caused by groundwater erosion or environmental exposure can be slowed down, and the sealing failure at the joint of the segments due to metal corrosion can be avoided.

[0085] In some specific embodiments, the anti-corrosion coating can be applied after the segment is demolded. For example, a high-pressure airless spraying device is used for construction in two times, and the coating thickness for each time is controlled between 25 μm and 30 μm, and the interval time between the two times is adjusted according to the curing characteristics of the coating.

[0086] Compared with the prior art, in traditional construction, the exposed parts of the steel plates of the first and last segment rings are not anti-corrosion treated, resulting in the steel plates being easily corroded by groundwater or environmental media, and then problems such as rusting of the anchor bars and accelerated aging of the waterproof rubber strips are caused. This solution improves the stability of the sealing system from the perspective of structural durability by adding an anti-corrosion layer.

[0087] Through the above technical solution, the present application significantly reduces the corrosion risk of the exposed steel structure of the first and last segment rings, maintains the long-term stability of the circumferential water stop ring and the end sealing structure, and thus can effectively prevent groundwater seepage problems during both the tunnel construction period and the operation period.

[0088] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A method for large-diameter slurry shield in multi-frequency earthquake zones, 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, embedding a first steel plate on the circumferential outer side of the first and last ring segments when forming the first and last ring segments, and providing a water stop strip on the circumferential inner side of the first steel plate close to the first and last ring segments; 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; Continue shield tunneling and simultaneously grouting between the installed pipe segments and the soil to stabilize the surrounding soil.

2. The large-diameter slurry shield method for multi-frequency earthquake zones according to claim 1, wherein 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 multi-frequency earthquake zones 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 multi-frequency earthquake belts according to claim 1, characterized in that, When forming the first and last ring segments, the process further includes pre-embedding a second steel plate at the first end of the first and last ring segments, wherein at least a portion of the second steel plate protrudes from the first end; The first end is located at one end of the first and last ring segments along a direction perpendicular to the circumferential direction.

5. The large-diameter slurry shield method for multi-frequency earthquake zones according to claim 4, characterized in that, 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; The first steel plate and the second steel plate are installed in a mold, and the first and last ring segments are formed by grouting, so that the first steel plate is located on the circumferential outside of the first and last ring segments, and at least part of the second steel plate protrudes from the first end of the first and last ring segments.

6. The large-diameter slurry shield method for multi-frequency earthquake-prone zones according to claim 5, 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.

7. The large-diameter slurry shield method for multi-frequency earthquake zones according to claim 5, 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.

8. The large-diameter slurry shield method for multi-frequency seismic belts according to claim 5, characterized in that, The load-bearing capacity of a single anchor bar welded to the second steel plate is calculated using the following formula: Among them, 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 bar material, and S is the safety factor, with a value range of 1.5 to 3.

0.

9. The large-diameter slurry shield method for multi-frequency earthquake zones according to claim 5, characterized in that 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.

10. The large-diameter slurry shield method for multi-frequency seismic belts according to claim 5, characterized in that, After the grouting and forming of the first and last segment linings, an anti-corrosion coating is applied to the part of the first steel plate protruding from the circumferential outer side of the first and last segment linings and the part of the second steel plate protruding from the first end to form an anti-corrosion coating layer; Control the thickness of the anti-corrosion coating layer to be not less than 50 μm.

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