Shield tunnel blocking structure and construction method thereof

Abstract

The invention relates to a shield tunnel blocking structure and a construction method thereof. The shield tunnel blocking structure comprises a lining steel plate ring arranged in a shield tunnel, a blocking steel plate and a support system. The shield tunnel comprises a lining ring formed by splicing a plurality of shield tunnel segments. The lining steel plate ring is formed by splicing a plurality of steel plates and anchored to the shield tunnel segment through anchor bolts. The support system comprises an annular support and door-shaped supports, the annular support is annularly installed on the inner ring of the lining steel plate ring, and the door-shaped supports are arranged on the inner ring of the annular support in a staggered mode; a detachable blocking steel plate is installed between the annular support and the door-shaped support. The shield tunnel blocking structure is rapid, convenient and safe in construction, small in influence on an existing structure, high in durability and capable of being used for rapidly blocking the shield tunnel, and the defects that after the shield tunnel collapses, due to the fact that plain concrete is backfilled in the tunnel, the backfill volume is large, the effect is slow, and the dismantling workload is large are overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of shield tunnels, and particularly relates to a shield tunnel plugging structure and a construction method thereof. Background Art

[0002] At present, with the rapid development of domestic rail transit and in various river-crossing tunnel projects, the shield tunneling method, with its advantages of high speed, high safety, and little impact, has an increasing proportion in tunnel projects. Especially in water-rich soft soil and sandy soil strata, such strata have characteristics such as high confined water head and strong formation permeability, and the shield tunnel method is often the first choice for tunnel construction methods. During the tunnel construction process, various construction links are highly risky, and any carelessness may cause serious consequences. Especially in water-rich soft soil or sandy layers, the abundant groundwater and granular sandy soil in the strata require high safety for tunnel construction.

[0003] With the wide application of shield tunnels in China, shield tunnel safety construction accidents caused by various reasons emerge in an endless stream. In severe cases, it can cause the collapse and abandonment of the entire tunnel, posing a great safety impact on the surrounding environment and buildings. During the construction of shield tunnels in water-rich and sand-rich geological conditions, due to various reasons, the high-confined water outside is likely to penetrate the sealing brush at the tail of the shield machine, resulting in the influx of sandy soil and groundwater outside into the shield machine. When the sealing brush is not blocked in time, the sandy soil and groundwater outside will flood the entire shield machine and the previously completed shield tunnel, and the ground will collapse due to soil erosion above the tunnel. Among them, some tunnels collapse due to uneven stress in the upper part of the tunnel structure, causing further ground collapse.

[0004] Tunnel engineering is a high-risk underground project. Different from ground engineering, tunnel engineering has characteristics such as irreversibility and difficulty in repair. During the repair process, in order to retain the complete tunnel as much as possible, an open-cut shaft needs to be set between the complete tunnel and the collapsed tunnel. How to ensure the construction safety of the open-cut shaft has become a difficult problem.

[0005] For example, when temporarily plugging a shield tunnel, an open-cut shaft needs to be set around the existing tunnel structure. The adverse effects of the existing tunnel on each construction process of the open-cut shaft should be considered, such as 1) how to solve the grooving problem caused by the free face of the existing tunnel during the diaphragm wall grooving process of the retaining structure of the open-cut shaft, and 2) how to solve the problem of the force on the retaining structure caused by the free face of the existing tunnel during the excavation process of the open-cut shaft. Currently, the commonly used technical means are mainly to backfill the existing tunnel around the open-cut shaft with concrete in the tunnel or on the ground surface, and to set a plain concrete (such as Figure 1 ) or reinforced concrete plugging wall structure (such as Figure 2 ) in the complete tunnel.

[0006] In the prior art, a Chinese invention patent with the publication number CN 118030112 A discloses a method for in-situ repair of accident shield tunnels. Regarding the sealing wall mentioned therein, when a plain concrete sealing wall is adopted, the water and soil pressure is mainly resisted by the anti-sliding force between the plain concrete and the intact tunnel structure. Considering the working conditions of backfilling plain concrete in the tunnel, it is necessary to stack temporary structures such as cement bags at both ends of the backfill to facilitate the smooth pouring of plain concrete, and finally form a trapezoidal backfill structure longitudinally in the tunnel. The longitudinal length of this structure generally needs to be reviewed in combination with the calculation of the anti-sliding force. When the tunnel burial depth is 30 m, the longitudinal effective length of the backfill is about 8 m. Considering the length of the 1:1 slope sections at both ends, the longitudinal length of the backfill is 8 + 5.5 + 5.5 = 19 m. The volume of the backfill reaches 320 m 3 , the backfilling workload is large and needs to be cleaned during the subsequent tunnel restoration process. When considering the scheme of a counterfort retaining wall reinforced concrete structure with a small backfill volume, this structure is composed of a ring beam, end walls, rear counterforts, etc. This technology requires implanting steel bars in the existing tunnel to effectively connect the sealing wall structure with the existing tunnel. Considering that the thickness of the segment structure of the existing rail transit tunnel is generally about 300 - 350 mm, in order to meet the requirements of the implanting length and diameter of the steel bars, a large number of small-diameter steel bars need to be arranged to meet the requirements of steel bar stress and construction regulations. After a large number of drilling and implanting steel bars are carried out on the intact tunnel segment structure and the reinforced concrete sealing wall structure is poured, the sealing wall structure needs to be demolished later. The processes of implanting steel bars and demolition will directly have an adverse impact on the integrity and durability of the segment structure. Therefore, it is necessary to study a structure with little impact on the existing structure and high durability.

[0007] In addition, when emergency sealing is required in case of danger in the shield tunnel, the method of in-situ backfilling with plain concrete in the tunnel is generally adopted to form a backfill to achieve the effect of longitudinally resisting water and soil pressure. However, when temporarily sealing with plain concrete in the tunnel, there are disadvantages such as a large backfill volume, slow effect exertion, and large demolition workload. Therefore, it is also necessary to study a more efficient and simple sealing structure. Summary of the Invention

[0008] The present invention is proposed to solve the above deficiencies, and the purpose is to provide a shield tunnel sealing structure and its construction method. This sealing structure is fast, convenient, and safe in construction in the tunnel, and has little impact on the existing structure and high durability.

[0009] In order to achieve the above purposes, the present invention adopts the following solutions:

[0010] A shield tunnel sealing structure includes a lining steel plate ring, a sealing steel plate, and a support system arranged in the shield tunnel;

[0011] The shield tunnel includes a lining ring formed by assembling a number of shield tunnel segments; the inner lining steel plate ring is formed by assembling a number of steel plates and is anchored to the shield tunnel segments by anchor bolts.

[0012] The support system includes an annular support and a portal support. The annular support is installed circumferentially inside the inner lining steel plate ring, and the portal supports are arranged staggeredly inside the annular support.

[0013] A detachable sealing steel plate is installed between the annular support and the portal support.

[0014] As a preferred embodiment, the inner lining steel plate ring is made of Q355B material, with a thickness of 2 - 5 cm, a ring width of 1200 - 1500 mm, and is prefabricated into 5 - 6 steel plates according to the inner wall shape of the shield tunnel segments. The steel plates are connected by welding and CO2 gas shielded welding is used.

[0015] As a preferred embodiment, the gap between the inner lining steel plate ring and the shield tunnel segments is filled tightly with epoxy resin.

[0016] As a preferred embodiment, the anchor bolts are inverted hammer-shaped chemical anchor bolts and / or under-reamed anchor bolts.

[0017] As a preferred embodiment, the annular support and the portal support in the support system are respectively made of Q335B material and I-shaped steel with a specification of I20a.

[0018] The annular support is composed of several annular steel sections connected by bolts, and the portal support is composed of several portal steel sections connected by bolts. Steel backing plates and rubber waterstops are provided at the bolt connection points.

[0019] The contact surface between the annular support and the inner lining steel plate ring is connected by welding process to form a weld seam, and the weld seam height is not less than 8 mm; the gap between the annular support and the inner lining steel plate ring is filled with epoxy resin.

[0020] As a preferred embodiment, steel rib plates are provided around the connection nodes of the annular support and the portal support, and the steel rib plates are connected by weld seams.

[0021] As a preferred embodiment, the sealing steel plate is made of Q355B material with a thickness of 2 - 5 cm; the sealing steel plate is connected to the annular support and the portal support by bolts, and rubber waterstops are provided at the bolt connection points.

[0022] As a preferred embodiment, secondary grouting reinforcement is formed by grouting outside the shield tunnel segments.

[0023] The present invention also provides a construction method for the above-mentioned shield tunnel sealing structure, including the following steps:

[0024] S1: In the area around the plugging structure to be set in the shield tunnel, secondary grouting is carried out on the soil outside the shield tunnel segments to form a secondary grouting reinforcement body, and longitudinal tying is carried out.

[0025] S2: Drill holes in the shield tunnel segments where the plugging structure is to be set, install a lining steel plate ring, and fill the gap between the lining steel plate ring and the shield tunnel segments with epoxy resin.

[0026] S3: Install a ring-shaped support and a portal support on the lining steel plate ring.

[0027] S4: Install a plugging steel plate between the ring-shaped support and the portal support, and use a rubber water stop plate to strengthen the water stop for the gaps between the components.

[0028] As a preferred embodiment, in step S3, if it is used for the emergency plugging of the shield tunnel, the portal support is installed in two times. The connecting members at the ends of the portal support are installed for the first time, and the frames of the remaining portal support are quickly assembled for the second time during plugging.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] First, the present invention provides a plugging structure in the tunnel that is fast, convenient, safe, has little impact on the existing structure, and has high durability after the collapse of the shield tunnel; in addition, it can also be used for quickly plugging the shield tunnel, avoiding the disadvantages of large backfill volume, slow effect, and large demolition workload of the backfill plain concrete in the tunnel after the collapse of the shield tunnel.

[0031] Second, the plugging structure adopted by the present invention, which is composed of a ring-shaped, portal support and a plugging steel plate, can be quickly installed when needed to achieve timely plugging; after the plugging task is completed, it can be conveniently disassembled or removed in blocks without affecting the later use or maintenance of the tunnel; the ring-shaped support, portal support and lining steel plate ring of the present invention form mutual support, sharing external loads such as water and soil pressure and soil layer stress; through staggered arrangement, the overall force balance and stiffness between components are enhanced; the installation sequence and quantity of the supports can be adjusted according to the construction site conditions to meet different space or emergency requirements; the present invention adds a lining steel plate ring inside the shield tunnel segments, and installs a support system and a plugging steel plate on it, without large-scale modification of the original tunnel structure, ensuring construction safety and reducing construction risks.

[0032] Thirdly, the inner lining steel plate ring of the present invention selects Q355B steel plate, which ensures sufficient strength, toughness and corrosion resistance, can bear the pressure environment in the tunnel for a long time, and the thickness and width of the ring can adapt to different design requirements. It is prefabricated with steel plates and assembled by CO2 shielded welding, with high construction efficiency, convenient transportation and installation, and more reliable welding quality. Before prefabrication, the steel plates can be lofted on site and cut into arc segments, which can fit tightly with the segments, improving the overall stability and anti-seepage performance.

[0033] Fourthly, the gap between the inner lining steel plate ring of the present invention and the segments of the shield tunnel is filled tightly with epoxy resin. Epoxy resin itself has good adhesion and strength, can effectively fill the tiny gaps between the steel plate and the segments, thus avoiding the phenomenon of hollowing or local stress concentration. After being filled tightly, it can significantly reduce the risk of water, moisture, etc. penetrating through the gaps, enhancing the overall waterproof effect of the sealing system. Epoxy resin has excellent anti-aging, corrosion resistance and fatigue resistance, which can greatly extend the service life of the sealing structure.

[0034] Fifthly, the anchor bolts of the present invention adopt inverted hammer-shaped chemical anchor bolts and under-reamed anchor bolts. The inverted hammer-shaped or under-reamed anchor bolts can form a larger mechanical biting area in the grouting hole, providing more reliable pull-out bearing capacity, and can maintain stable connection in high water pressure, large dynamic load or vibration environment, reducing the risk of anchor bolt loosening and pulling off. Compared with traditional expansion anchor bolts, chemical anchor bolts are more flexible in construction and are suitable for a variety of substrates and site conditions.

[0035] Sixthly, the bracket system of the present invention selects Q335B I20a steel, which can obtain sufficient strength and stiffness, ensuring that it is not easy to deform under high soil and water pressure, and is stable and reliable; whether it is a circular bracket or a portal bracket, it is assembled by several steel sections, and bolt connection speeds up the installation speed and is also convenient for later removal and maintenance; steel backing plates are added at the bolt connection to help disperse stress; rubber water stop plates further enhance the water tightness and prevent water from penetrating along the connection; the weld height is not less than 8mm, which can effectively transfer shear force and axial force, enhancing the reliability of the connection between the bracket and the inner lining steel plate ring.

[0036] Seventhly, steel rib plates are arranged around the connection nodes of the circular bracket and the portal bracket of the present invention and are connected by welds. Welding steel rib plates near the connection nodes of the steel sections can effectively reinforce the weak parts of the nodes, improving the bending, shear and torsional resistance performance of the overall frame; due to the concentrated stress at the nodes, fatigue or deformation is more likely to occur. After adding steel rib plates, the fatigue life and safe service period of the components can be significantly extended; the steel rib plates are firmly fixed to the brackets by welds and are not easy to loosen, meeting the long-term stable operation under complex load conditions.

[0037] Eighth, the plugging steel plate of the present invention is made of Q355B material and is connected to the annular bracket and the gantry bracket by bolts. The bolt connection is provided with a rubber water stop plate. Q355B steel has good mechanical properties and can withstand large water pressure or impact loads. The bolt connection method is convenient for quick installation or removal when needed, reducing the interference with tunnel operation or later maintenance. The addition of a rubber water stop plate at the bolt helps to block the water from penetrating through the connection pores or around the bolts, improving the overall waterproof efficiency of the plugging.

[0038] Ninth, the construction method of the present invention first conducts soil reinforcement, then installs the inner lining steel plate ring, then installs the support system, and finally installs the plugging steel plate, which can complete the entire plugging process orderly and controllably, ensuring quality and safety. Through the cooperation of materials such as epoxy resin and rubber water stop plate, strict plugging is achieved at each key node, reducing the impact of water or mud on the construction. Moreover, it has the characteristics of fast construction speed and high engineering quality guarantee. At present, it has been successfully applied to many shield engineering cases in rail transit. In addition, this technology is not limited to the rail transit industry and can also be used in shield tunnel engineering in industries such as municipal, highway, and water conservancy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is the longitudinal sectional view of the plugging structure with plain concrete backfill and the open cut shaft in the prior art;

[0040] Figure 2 is the longitudinal sectional view of the plugging structure with reinforced concrete retaining wall and the open cut shaft in the prior art;

[0041] Figure 3 is the longitudinal sectional view of the plugging structure of the present invention and the open cut shaft;

[0042] Figure 4 is the elevation layout drawing of the shield tunnel and the plugging structure of the present invention;

[0043] Figure 5 is Figure 4 the longitudinal sectional layout drawing along the I-I in

[0044] Figure 6 is the elevation layout drawing of the plugging structure of the present invention;

[0045] Figure 7 is Figure 6 the enlarged structural schematic diagram at point A in

[0046] Figure 8 is Figure 6 the enlarged structural schematic diagram at point B in

[0047] Figure 9 is Figure 6 the enlarged structural schematic diagram at point C in

[0048] Figure 10 This is the longitudinal emergency plugging distribution diagram of the shield tunnel of the present invention;

[0049] Figure 11 This is the schematic diagram of the first step of the construction of the plugging structure of the shield tunnel in the embodiment of the present invention;

[0050] Figure 12 This is the schematic diagram of the second step of the construction of the plugging structure of the shield tunnel in the embodiment of the present invention;

[0051] Figure 13 This is the schematic diagram of the third step of the construction of the plugging structure of the shield tunnel in the embodiment of the present invention, which shows the installation of the connecting members at the ends of the portal support;

[0052] Figure 14 This is the schematic diagram of the third step of the construction of the plugging structure of the shield tunnel in the embodiment of the present invention, which shows the installation of the overall portal support;

[0053] Figure 15 This is the schematic diagram of the fourth step of the construction of the plugging structure of the shield tunnel in the embodiment of the present invention;

[0054] In the figure: segment of shield tunnel 1, support system 2, annular support 2-1, portal support 2-2, anchor bolt 3, inner lining steel plate ring 4-1, plugging steel plate 4-2, bolt 5-1, steel backing plate 5-2, steel rib plate 5-3, weld 5-4, epoxy resin 6, rubber water stop plate 7, secondary grouting solidification body 8, longitudinal tie 8-1, open cut shaft 9-1, retaining structure 9-2, backfill body 9-3, longitudinal effective range backfill body 9-4, longitudinal retaining wall 10, implanted bar 10-1, shield machine 11. Detailed implementation manners

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] It should be understood that the accompanying drawings are only for illustrative purposes and cannot be construed as a limitation to this patent; for better illustrating this embodiment, some components in the accompanying drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted. The positional relationships described in the accompanying drawings are only for illustrative purposes and cannot be construed as a limitation to this patent.

[0057] As Figures 3 to 10As shown in the figure, a shield tunnel plugging structure of the present invention includes a lining steel plate ring 4-1, a plugging steel plate 4-2 and a support system 2 arranged in the shield tunnel; the shield tunnel includes a lining ring formed by assembling a plurality of shield tunnel segments 1. The lining steel plate ring 4-1 is formed by assembling a plurality of steel plates and is anchored to the shield tunnel segment 1 by anchor bolts 3. The lining steel plate ring 4-1 is made of Q355B material, with a thickness of 2-5 cm and a ring width of 1200-1500 mm. It is prefabricated into 5-6 steel plates according to the inner wall shape of the shield tunnel segment 1. The steel plates are connected by welding and CO2 gas shielded welding is used. The gap between the lining steel plate ring 4-1 and the shield tunnel segment 1 is filled tightly with epoxy resin.

[0058] In this embodiment, the lining steel plate ring 4-1 is made of Q355B material, with a 2-cm steel plate and a ring width of 1200 mm. The lining steel plate ring 4-1 is arranged in the middle closely against the reinforced shield tunnel segment 1. The gap between the lining steel plate ring 4-1 and the shield tunnel segment 1 is filled with the slurry of rigid epoxy resin 6. The lining steel plate ring 4-1 is made into 5-6 pieces as required. The steel plates are connected by welding and CO2 gas shielded welding is used. Since the shield tunnel lining ring within the reinforcement range of the lining steel plate ring 4-1 is a complete tunnel and the tunnel deformation is small, the size of the steel plate blocks arranged in each lining ring needs to be determined in advance by on-site lofting to ensure that the lining steel plate ring 4-1 fits the inner wall of the shield tunnel segment 1. The gap between the lining steel plate ring 4-1 and the shield tunnel segment 1 is filled tightly with epoxy resin 6.

[0059] To effectively connect the lining steel plate ring 4-1 with the shield tunnel, after drilling the structure of the shield tunnel segment 1, chemical anchor bolts 3 such as specially configured organic modified vinyl ester type anchoring glue or modified vinyl ester type adhesives are used for bonding. The corresponding anchoring glue material needs to meet requirements such as axial pull-out test, corrosion resistance, durability, etc., and meet the qualified index of Class A glue performance.

[0060] To effectively connect the lining steel plate ring 4-1 with the shield tunnel, the steel plate surface is reinforced with anchor bolts 3. The anchor bolts 3 are M16, 8.8-grade special inverted hammer-shaped chemical anchor bolts and M16, 8.8-grade under-reamed anchor bolts. The anchor bolts 3 should meet requirements such as not less than relevant durability and fire resistance. When used for tunnel emergency plugging, during the tunneling of the shield machine 11, several lining steel plate rings 4-1 can be arranged longitudinally in the tunnel in advance according to the size of the tunnel construction risk. When the plugging structure needs to be activated, the plugging structure can be provided at any time.

[0061] The support system 2 includes an annular support 2-1 and a portal support 2-2. The annular support 2-1 is circumferentially installed on the inner ring of the lining steel plate ring 4-1, and the portal supports 2-2 are staggeredly arranged on the inner ring of the annular support 2-1; a detachable plugging steel plate 4-2 is installed between the annular support 2-1 and the portal support 2-2. The annular support 2-1 is connected by a plurality of annular steel sections through bolts 5-1, and the portal support 2-2 is connected by a plurality of portal steel sections through bolts 5-1. Steel backing plates 5-2 and rubber water stop plates 7 are provided at the bolt 5-1 connection points.

[0062] In this embodiment, in order to transfer the water and soil pressure transmitted axially by the tunnel to the tunnel and the lining steel plate ring 4-1, the annular support 2-1 and the portal support 2-2 are used for connection on the inner surface of the lining steel plate ring 4-1 of the shield tunnel. The annular support 2-1 and the portal support 2-2 are made of Q335B and have a specification of I20a. They are mainly connected by bolts 5-1 and locally welded by welds 5-4. In this embodiment, the annular support 2-1 is made in 4 pieces as required, and the annular supports 2-1 are connected by bolts 5-1. The gap between the annular support 2-1 and the lining steel plate ring 4-1 is filled with epoxy resin 6.

[0063] To ensure effective connection between the annular support 2-1 and the lining steel plate ring 4-1, a welding process is used for connection on the contact surfaces of the annular support 2-1 and the lining steel plate ring 4-1, and the height of the weld 5-4 is not less than 8 mm. To ensure effective force transmission, around the connection nodes between the annular support 2-1 and the portal support 2-2, steel rib plates 5-3 are used to strengthen the node structure. The steel rib plates 5-3 are made of Q335B, with a thickness of 2 cm, and 4 to 5 pieces are arranged on both sides of the web of the steel section, with a spacing of about 300 mm, and they are connected by welds 5-4.

[0064] The portal support 2-2 can be made in multiple pieces as required, and the portal steel sections are connected by bolts 5-1. To improve the water stop performance between the steel sections, a rubber water stop plate 7 is provided at the bolt 5-1 connection points. When used for emergency plugging of the tunnel, annular steel sections are arranged on the basis of the already arranged lining steel plate ring 4-1, as well as the end connection members of the portal support 2-2; when a danger occurs, the remaining portal supports 2-2 can be quickly installed.

[0065] The plugging steel plate 4-2 is made of Q355B, with a thickness of 2 to 5 cm, preferably 2 cm. The plane size is determined according to the steel support, and the size is generally between 1100 and 1800 mm; the plugging steel plate 4-2 is connected to the annular support 2-1 and the portal support 2-2 through bolts 5-1, and rubber water stop plates 7 are provided at the bolt 5-1 connection points.

[0066] After the installation of the ring support 2-1 and the portal support 2-2 is completed, the ring support 2-1 and the portal support 2-2 are connected by a sealing steel plate 4-2. For quick installation, the sealing steel plate 4-2 and the section steel support are connected by bolts 5-1. To improve the water-stop performance between the sealing steel plate 4-2, the ring support 2-1 and the section steel of the portal support 2-2, a rubber water-stop plate 7 is provided at the connection of the bolts 5-1.

[0067] When used for emergency plugging of the tunnel, the sealing steel plate 4-2 is quickly installed on the basis of the already arranged ring support 2-1 and portal support 2-2.

[0068] For the post-grouting behind the shield tunnel lining, to improve the bearing capacity of the soil around the backfill body 9-3 of the shield tunnel and improve the stress of the shield tunnel segments 1, secondary grouting is carried out on the shield tunnel segments 1 on both sides of the inner lining steel plate ring 4-1 reinforcement system for 3 to 5 rings, and longitudinal tie-ins are made for the segment structure. It is advisable to give priority to using the reserved grouting holes of the segments for post-grouting behind the lining.

[0069] The grouting material can be selected as cement slurry or double-fluid slurry according to the formation conditions, and the appropriate grouting pressure and the grouting quantity per single hole are selected according to the properties of the slurry and the formation conditions outside the tunnel. During the grouting process, the vertical ground displacement, the settlement of the segment crown and the surrounding convergence, etc. should be strengthened for monitoring.

[0070] When used for emergency plugging of the tunnel, during the tunneling of the shield machine 11 and before setting the inner lining steel plate ring 4-1, the soil outside the tunnel can be pre-reinforced by secondary grouting to form a secondary grouting reinforcement body 8.

[0071] The construction method of the shield tunnel plugging structure of the present invention includes the following steps:

[0072] S1: As Figure 11 shown, in the area around the periphery of the shield tunnel where the plugging structure is to be set, secondary grouting is carried out on the soil outside the shield tunnel segments 1 to form a secondary grouting reinforcement body 8, and longitudinal tie-ins 8-1 are constructed;

[0073] S2: As Figure 12 shown, holes are drilled in the shield tunnel segments 1 where the plugging structure is to be set, and the inner lining steel plate ring 4-1 is installed. For the gap between the inner lining steel plate ring 4-1 and the shield tunnel segments 1, epoxy resin is used for filling;

[0074] S3: As Figures 13 to 14 shown, the ring support 2-1 and the portal support 2-2 are installed on the inner lining steel plate ring 4-1; if it is used for the emergency plugging situation of the shield tunnel, the portal support 2-2 is installed in two times. The connecting members at the ends of the portal support 2-2 are installed for the first time so as not to affect the normal construction operation of the shield, and the frame of the remaining portal support 2-2 is quickly assembled for the second time during plugging;

[0075] S4: As shown Figure 15 in Figure Figure 15 , install the plugging steel plate 4-2 between the annular support 2-1 and the portal support 2-2, and use rubber water stop plates to strengthen the water stop for the gaps between various components. When the plugging function is expected to be cancelled in the future, the plugging steel plate, the annular support 2-1 and the portal support 2-2 can be removed in pieces, and the inner lining steel plate ring can be retained inside the tunnel.

[0076] The above embodiments are only examples of the technical solutions of the present invention. The present invention is not limited only to the content described in the above embodiments, but is subject to the scope defined by the claims. Any modification, supplement or equivalent replacement made by those skilled in the art to which the present invention pertains based on this embodiment is within the scope protected by the claims of the present invention.

Claims

1. A shield tunnel plugging structure, characterized in that: It includes a lining steel plate ring (4-1), a sealing steel plate (4-2) and a support system (2) arranged in the shield tunnel; The shield tunnel includes a lining ring formed by assembling a number of shield tunnel segments (1); the lining steel plate ring (4-1) is formed by assembling a number of steel plates and is anchored to the shield tunnel segment (1) by anchor bolts (3); The support system (2) includes an annular support (2-1) and a portal support (2-2). The annular support (2-1) is installed circumferentially inside the lining steel plate ring (4-1), and the portal supports (2-2) are arranged staggeredly inside the annular support (2-1); A detachable sealing steel plate (4-2) is installed between the annular support (2-1) and the portal support (2-2).

2. The shield tunnel plugging structure according to claim 1, characterized in that: The lining steel plate ring (4-1) is made of Q355B material, with a thickness of 2 - 5 cm and a ring width of 1200 - 1500 mm. It is prefabricated into 5 - 6 steel plates according to the inner wall shape of the shield tunnel segment (1). The steel plates are connected by welding and CO2 gas shielded welding is used.

3. The shield tunnel plugging structure according to claim 2, characterized in that: The gap between the lining steel plate ring (4-1) and the shield tunnel segment (1) is filled tightly with epoxy resin.

4. The shield tunnel plugging structure according to claim 1 or 2 or 3, characterized in that: The anchor bolts (3) are inverted hammer-shaped chemical anchor bolts and / or under-reamed anchor bolts.

5. The shield tunnel plugging structure according to claim 1 or 2 or 3, characterized in that: The annular support (2-1) and the portal support (2-2) in the support system (2) are respectively made of section steel of Q335B material and specification No. 20a I-beam; The annular support (2-1) is connected by a number of annular section steels through bolts (5-1), and the portal support (2-2) is connected by a number of portal section steels through bolts (5-1). Steel backing plates (5-2) and rubber water stop plates (7) are arranged at the bolt (5-1) connection points; The contact surface between the annular support (2-1) and the lining steel plate ring (4-1) is connected by welding process to form a weld (5-4), and the weld height is not less than 8 mm; the gap between the annular support (2-1) and the lining steel plate ring (4-1) is filled with epoxy resin.

6. The shield tunnel plugging structure according to claim 5, wherein: Steel rib plates (5-3) are arranged around the connection nodes of the annular support (2-1) and the portal support (2-2), and the steel rib plates (5-3) are connected by welds.

7. The shield tunnel plugging structure according to claim 5, characterized in that: The sealing steel plate (4-2) is made of Q355B material with a thickness of 2 - 5 cm; the sealing steel plate (4-2) is connected to the annular support (2-1) and the portal support (2-2) by bolts (5-1), and rubber water stop plates (7) are arranged at the bolt (5-1) connection points.

8. The shield tunnel plugging structure according to claim 1 or 2 or 3, characterized in that: Secondary grouting reinforcement (8) is formed by grouting outside the shield tunnel segment (1).

9. A construction method for the shield tunnel plugging structure according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1: Secondary grouting is carried out on the soil outside the shield tunnel segment (1) in the peripheral area of the proposed sealing structure in the shield tunnel to form secondary grouting reinforcement (8), and longitudinal tie is carried out; S2: Holes are drilled in the shield tunnel segment (1) where the sealing structure is to be installed, and the lining steel plate ring (4-1) is installed. The gap between the lining steel plate ring (4-1) and the shield tunnel segment (1) is filled with epoxy resin; S3: Install the annular bracket (2-1) and the portal bracket (2-2) on the inner lining steel plate ring (4-1); S4: Install the blocking steel plate (4-2) between the annular bracket (2-1) and the portal bracket (2-2), and use a rubber water stop plate to strengthen the water stop for the gaps between the components.

10. The construction method of the shield tunnel plugging structure according to claim 9, characterized in that: In the step S3, if it is for the emergency blocking situation of the shield tunnel, the portal bracket (2-2) is installed in two times. The connecting members at the ends of the portal bracket (2-2) are installed for the first time, and the frames of the remaining portal brackets (2-2) are quickly assembled for the second time during blocking.

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