A method for lining construction of a shield body in river bottom butt joint

Abstract

The application provides a shield body lining construction method during river bottom butt joint, and relates to the field of shield construction. The whole lining plays a role of supporting the shield body, prevents the shield body from being unstable and deformed, and saves the layout of frozen discharge pipes. Specifically, the method comprises the following steps: step 1: after two shield machines are butt jointed at the river bottom, a group of shield oil cylinders are retracted, and a circle of stop plates are welded on the shield segments of the last ring of the two shield machines; step 2: local lining ring beams are cast at the positions corresponding to the stop plates; step 3: the shield oil cylinders are removed, and the shield H-beams and shield rib plates are cut off; step 4: three rows of frozen hole pipes are installed in the whole circle of the shield machine middle shield area, and the whole lining is cast, the frozen hole pipes are embedded in the whole lining, and the end portions of the frozen hole pipes are outside the whole lining; and step 5: freezing construction is carried out in the frozen hole pipes, and the frozen holes are sealed after the freezing construction is completed.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction, specifically a method for constructing the inner lining of the TBM during underwater docking. Background Technology

[0002] During the docking of two tunnel boring machines (TBMs) on the riverbed, to prevent the shield from becoming unstable and sliding backward, a backstop plate needs to be installed at the tail of the last ring of the TBM segment. The backstop plate is welded to the shield shell. While welding the backstop plate effectively solves the risk of instability caused by the jacks releasing force after disassembly, thus preventing the shield from sliding backward, the introduction of the backstop plate alters the original force transmission path of the TBM. For example... Figure 1 As shown, without the introduction of a backstop plate, the initial force transmission path of the tunnel boring machine is as follows: the horizontal water and soil pressure in front of the cutterhead is transmitted to the hydraulic cylinders through the front shield, and the hydraulic cylinders push against the segments, with the shield shell only bearing the water and soil confining pressure. Figure 2 As shown, after the anti-reverse plate is introduced, the water and soil pressure in front of the cutterhead is transmitted to the tunnel segments through the anti-reverse plate. As the jacks of the tunnel boring machine retract, the force transmission path of the shield body changes, and the water and soil pressure in front of the cutterhead needs to be borne by the shield shell.

[0003] Since the stiffness of the concrete tunnel segments is 15 times that of the shield shell, the large stiffness difference will make the anti-reverse plate connecting the segments and the shield body very unfavorable to the stress. If there is an incremental load from the outside, the deformation of the segments will be much smaller than that of the shield body. In this case, the anti-reverse plate is at risk of shear failure.

[0004] In addition, after docking, freezing construction must be carried out within the front and middle shields of the two tunnel boring machines. Freezing construction requires the construction of freezing holes on the shell of the middle shield. The freezing process takes up to 6 months, and the change in the force transmission path of the shield body can easily cause shield instability.

[0005] Furthermore, the remaining I-beams and ribs from dismantling the shield restrict the openings for freezing, and the large number of openings significantly weakens the shield's rigidity. Additionally, the significant temperature difference between the inside and outside of the shield during freezing can cause the frozen soil adhering to the outer surface of the shield to melt, creating seepage paths due to the higher construction temperatures inside the tunnel. Therefore, before normal freezing operations, multiple freezing pipes are arranged along the longitudinal direction of the shield on its inner side, such as... Figure 3 and Figure 4 As shown. Moreover, the frost heave force is very large during the freezing process, which can damage the shield.

[0006] In summary, changes in the force transmission path, dismantling of the shield structure, freezing of openings, and long freezing construction periods can all lead to shield instability issues. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned problems and shortcomings of the existing technology by designing a method for constructing the shield lining during docking at the riverbed. By first pouring the lining and then carrying out the freezing construction, the force transmission path of the shield remains unchanged during the freezing stage, and the overall lining plays a supporting role for the shield, thereby ensuring the stability of the shield.

[0008] A method for constructing the shield lining during underwater docking includes the following steps:

[0009] Step 1: The two tunnel boring machines (TBMs) tunnel towards each other and connect at the bottom of the river. After that, a set of TBM hydraulic cylinders are retracted, and a ring of anti-reverse plates is welded on the shield segments of the last stage of the tunneling construction of the two TBMs. The height of the anti-reverse plates is less than the thickness of the shield segments.

[0010] Step 2: Cast a partial inner lining ring beam at the corresponding position of the anti-reverse plate. The inner arc surface of the partial inner lining ring beam is on the same plane as the inner arc surface of the shield segment.

[0011] Step 3: Remove the shield cylinders, cut off the shield's U-shaped beams and shield ribs;

[0012] Step 4: Install the freezing orifice pipe between the two anti-reverse plates and pour the integral lining. The freezing orifice pipe is pre-embedded in the integral lining, and the end of the freezing orifice pipe is on the outside of the integral lining. The integral lining is poured before the freezing construction operation. The integral lining plays the role of supporting the shield body and ensuring the stability of the shield body.

[0013] Step 5: Perform freezing operations inside the freezing hole pipe, and seal the freezing hole after the freezing operations are completed.

[0014] Furthermore, before pouring the overall lining in step 4, studs are welded to ensure that the overall lining and the shield form a whole, ensuring that the overall lining and the shield form a composite component, share the load, and increase stability.

[0015] Preferably, within a unit 1-meter ring width, five studs with a diameter of 25mm and an anchoring length of 100mm are selected and arranged at a spacing of 200mm to ensure the shear capacity of the studs while reducing the welding difficulty.

[0016] Furthermore, in step 5, grouting is performed inside the freezing hole using a one-way ball valve, and then the hole is sealed by welding with a steel plate to reduce the impact of opening the freezing hole on the rigidity.

[0017] Preferably, the overall lining includes a first lining and a second lining. In step 4, the first lining is poured first, and after completing the freezing construction operation in step 5, the second lining is poured. This solves the problems of long freezing drilling paths and easy deviations in drilling angles due to the large thickness of the overall lining, and the difficulty of drilling additional holes if the freezing pipe is deviated. At the same time, the second lining ensures the sealing effect of the freezing holes and the waterproof effect of the lining.

[0018] Furthermore, before the first lining is poured, a first steel plate with a round hole and anchor bars is installed at the position of the installed freezing hole pipe. After freezing is completed, the first steel plate is welded and sealed with a second steel plate. Finally, the second lining is poured, and the second lining serves as a waterproof barrier.

[0019] Preferably, in step 3, the four sets of shield cylinders are removed, and the four sets of shield beams and shield ribs corresponding to the shield cylinders are cut off. At the same time as the removal, the first inner lining is poured to ensure that the longitudinal force transmission of the shield remains unchanged, improve the strength of the shield, solve the problem of shield stability, and avoid the water and soil pressure in front of the cutterhead acting on the shield shell, which would cause the shield to become unstable.

[0020] Preferably, both the tunnel segments and the overall lining are made of concrete. The overall thermal insulation properties of concrete are utilized, eliminating the need for refrigeration pipes and reducing the number of openings, thereby increasing the stability of the tunnel.

[0021] Furthermore, the shield shell and the first inner lining are treated as a combined unit, and the stiffness of the combined unit and the shield segments are set to be consistent to ensure the stability of the shield during construction, thereby solving for the optimal thickness of the first inner lining.

[0022] The optimal thickness of the first liner is determined by the following steps:

[0023] Step 4.1: Based on stiffness equivalence, the shield shell in the composite is equivalent to a first inner liner of the same thickness, then:

[0024] A s ′E c1 =A s E S

[0025] Among them, A S 'A' represents the area of ​​the shield shell after it is equivalent to the first inner liner. S E represents the actual area of ​​the shield before equivalence. c1 E represents the elastic modulus of the first liner. s This represents the elastic modulus of the shield.

[0026] Among them, A S 'and A S Refer to the following formulas respectively:

[0027] A′ s =b′×h s

[0028] A S =b×h s

[0029] Where b' represents the length of the shield shell after it is equivalent to the first inner liner, b represents the length of the shield shell before it is equivalent, and h sThis indicates the shield thickness; the equivalent shield thickness remains unchanged.

[0030] Substituting into the calculation, we get

[0031]

[0032] Due to E s >E c1 If the length b' of the shield shell after being equivalent to the first inner liner is greater than the length b of the shield shell before being equivalent to the first inner liner, then the equivalent combined body is a T-shaped structure, or simply an equivalent T-shaped section.

[0033] Step 4.2: Calculate the ordinate of the centroid of the equivalent T-section:

[0034]

[0035] Where y represents the ordinate of the centroid of the equivalent T-section, and A c1 h represents the area of ​​the first lining. c1 A represents the thickness of the first liner. c This indicates the area of ​​the tunnel lining segments.

[0036] Step 4.3: Calculate the moment of inertia of the centroid of the equivalent T-section:

[0037]

[0038] Among them, I Z The moment of inertia of the centroid of the equivalent T-section, y s The ordinate of the equivalent rear shield shell section relative to its centroid is represented by h. s / 2,y c1 This represents the ordinate of the section corresponding to the first lining relative to its centroid, i.e., h. c1 / 2;

[0039] Step 4.4: Construct the stiffness equations for the equivalent T-section and shield segments, and substitute them into the equation for I in Step 3. Z Solve for h c1 :

[0040] E Z I Z =ηE C I C

[0041] Where η represents the stiffness reduction factor, I C This represents the moment of inertia of the tunnel segment.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] The purpose of this invention is to address the aforementioned problems and shortcomings of the existing technology by designing a method for constructing the inner lining of the shield body during docking at the riverbed. This invention employs a construction method that involves first pouring the inner lining and then freezing the material, and by disassembling the inner lining during construction, it increases waterproofing and ensures the stability of the shield body.

[0044] 1. This invention ensures that the force transmission path of water and soil pressure in front of the tunnel boring machine remains unchanged by first pouring the inner lining, and then carrying out the external freezing construction of the shield body. The overall inner lining plays a role in supporting and strengthening the shield body, thereby ensuring the stability of the shield body.

[0045] 2. This invention divides the overall inner lining into a first inner lining and a second inner lining, and constructs them in stages. The hydraulic cylinders are removed in groups and the corresponding inner linings are poured to solve the problem of the large thickness of the overall inner lining and the difficulty of drilling when additional drilling is required. Furthermore, the inner lining constructed later can serve as a waterproof barrier, improving the safety of the tunnel boring machine.

[0046] 3. This invention involves dismantling the shield tunneling cylinders in groups, cutting off the corresponding shield beams and ribs, and simultaneously pouring the first inner lining. This ensures that the longitudinal force transmission of the shield remains unchanged, improves the shield's strength, and solves the shield's stability problem, preventing water and soil pressure in front of the cutterhead from causing instability. Furthermore, this invention calculates the optimal thickness of the first inner lining, ensuring construction stability while facilitating construction.

[0047] 4. This invention involves welding studs before the overall lining is poured to ensure that the lining and the shield form a unified whole, ensuring that they form a composite component that shares the load and increases stability. Calculations show that within a one-meter circumference, studs with a diameter of 25mm are selected, and within a contact area of ​​50.24㎡, three studs are placed per square meter, for a total of 151 studs. The longitudinal spacing is 0.333m, and the axial spacing is 0.5m, ensuring the studs' shear resistance while reducing welding difficulty.

[0048] 5. In this invention, a partial inner lining ring beam is cast at the corresponding position of the anti-reverse plate. The inner arc surface of the partial inner lining ring beam is flush with the inner arc surface of the shield segment, so that it can serve as a supporting component of the shield body and play a supporting role in the subsequent dismantling process. In addition, it is beneficial to the anti-reverse device to bear the force and avoid deformation and failure of the anti-reverse device. Attached Figure Description

[0049] Figure 1 The force transmission path in the existing shield tunneling docking process does not include an anti-backflow plate;

[0050] Figure 2 To add a force transmission path for the anti-backflow plate during the existing shield tunneling docking process;

[0051] Figure 3Cross-sectional view of the refrigeration pipe layout for existing shield tunneling technology;

[0052] Figure 4 Longitudinal section diagram of refrigeration pipe layout for existing shield tunneling technology;

[0053] Figure 5 A schematic diagram of the shield lining structure designed for this invention, which involves first pouring the inner lining and then freezing the construction.

[0054] Figure 6 This is a schematic diagram showing the shield shell being equivalent to a first inner liner when calculating the optimal thickness in this invention. Detailed Implementation

[0055] The following detailed description, in conjunction with the accompanying drawings and specific implementation methods, provides a further detailed explanation of the shield lining construction method for underwater docking according to the present invention.

[0056] Example 1

[0057] This invention proposes a method for constructing the shield body lining during underwater docking, such as... Figure 5 As shown, it includes the following steps:

[0058] Step 1: The two tunnel boring machines (TBMs) tunnel towards each other and connect at the bottom of the river. After that, a set of TBM hydraulic cylinders are retracted, and a ring of anti-reverse plates is welded on the shield segments of the last stage of the tunneling construction of the two TBMs. The height of the anti-reverse plates is less than the thickness of the shield segments.

[0059] Step 2: Cast a partial inner lining ring beam at the corresponding position of the anti-reverse plate. The inner arc surface of the partial inner lining ring beam is flush with the inner arc surface of the shield segment. The functions of the partial inner lining ring beam are: 1. It can serve as a supporting component for the shield body and play a supporting role in the subsequent dismantling process; 2. It is beneficial to the anti-reverse device to bear the force and avoid deformation and failure of the anti-reverse device.

[0060] Step 3: Remove the shield cylinders, cut off the shield's U-shaped beams and shield ribs;

[0061] Step 4: Install the freezing orifice pipe between the two anti-reverse plates and pour the integral lining. The freezing orifice pipe is pre-embedded in the integral lining, and the end of the freezing orifice pipe is on the outside of the integral lining. The integral lining is poured before the freezing construction operation. The integral lining plays the role of supporting the shield body and ensuring the stability of the shield body.

[0062] Step 5: Perform freezing operations inside the freezing hole pipe, and seal the freezing hole after the freezing operations are completed.

[0063] Furthermore, before pouring the overall lining in step 4, studs are welded to ensure that the overall lining and the shield form a whole, ensuring that the overall lining and the shield form a composite component, share the load, and increase stability.

[0064] Preferably, within a one-meter circumference, studs with a diameter of 25mm are selected. Within a contact area of ​​50.24㎡, three studs are placed per square meter, for a total of 151 studs. The longitudinal spacing is 0.333m, and the axial spacing is 0.5m, ensuring the shear capacity of the studs while reducing welding difficulty. The stud placement utilizes finite element software to create a two-dimensional model of the shield shell and the overall lining assembly. The contact friction between the shield shell and the overall lining sections is established, and under external water and soil pressure, circumferential shear force is generated at the coplanar contact surface between the shield shell and the overall lining.

[0065] Specifically, such as Figure 6 As shown, the geometric model uses a unit ring width of 1 meter, an 80mm thick Q355 steel shell, and a 380mm thick C60 concrete. The outer diameter of the steel shell is 16 meters. Boundary conditions include: ① limiting displacement along the shield tunnel direction; ② foundation reaction force - soil spring: the normal spring stiffness of the foundation is k = 370000 N / m, and the tangential spring stiffness can be taken as 1 / 3 of the normal spring stiffness, i.e., 123333 N / m; ③ steel shell and concrete contact: the normal direction adopts "hard" contact, and the tangential direction selects "penalty friction" contact, with a friction coefficient of 0.35. The loads consider the effects of soil and water pressure and frost heave.

[0066] Based on Abaqus software, loads were applied to the model, and Mises stress diagrams of the shield shell, the overall lining, the combined structure of the shield shell and the overall lining, as well as the transverse displacement diagram, the vertical displacement diagram, and the axial displacement diagram of the overall lining were constructed.

[0067] Then, output the circumferential shear force cloud diagram of the contact surface of the combined structure of the shield shell and the integral lining. Since the maximum circumferential shear force between the shield shell and the integral lining ring is 271.1KN, and the load partial factor is taken as 1.3, the maximum circumferential shear force between the shield shell and the concrete integral lining ring is taken as 352.43KN.

[0068] Finally, the number of studs within a one-meter circumference along the axial direction (in the direction of tunnel boring) was calculated when the stud diameter was 19mm, 22mm, and 25mm respectively.

[0069] Based on shear stress, and referring to the shear connection of composite beams, cylindrical head weld studs are recommended. The design value of the shear bearing capacity of a single shear connection is... It should be determined by the following formula:

[0070] Cylindrical head weld stud connector:

[0071]

[0072] In the formula: Ec represents the elastic modulus of concrete (N / mm²). 2 The elastic modulus of C60 concrete is taken as 36000 (N / mm). 2 );

[0073] As represents the cross-sectional area of ​​the cylindrical head weld stud shank (mm²). 2 );

[0074] Fc represents the axial compressive strength of concrete (N / mm²). 2 The axial compressive strength of C60 concrete is taken as 27.5 (N / mm²). 2 );

[0075] fu represents the design value of the ultimate tensile strength of the cylindrical head stud, which must meet the requirements of the current national standard GB / T 10433 "Cylindrical Head Studs for Arc Stud Welding" (N / mm²). 2 ), fu is taken as 400 (N / mm 2 ).

[0076] The studs are arranged according to the maximum circumferential shear force Vs. For the most unfavorable design condition, the total number of shear connectors n is [number missing]. f Calculation formula:

[0077]

[0078] The calculation results are shown in the table below:

[0079] Table 1. Number of bolts per meter of circumference along the axial direction (tunneling direction)

[0080]

[0081] Taking into account the shear capacity of the studs and the difficulty of welding, within a unit circumference of one meter, a stud diameter of 25mm was selected. Within a contact area of ​​50.24㎡, 3 studs were set per square meter, for a total of 151 studs, with a longitudinal spacing of 0.333m and an axial spacing of 0.5m.

[0082] Preferably, in step 5, grouting is performed inside the freezing hole using a one-way ball valve, and then the hole is sealed by welding with a steel plate to reduce the impact of opening the freezing hole on the rigidity.

[0083] Example 2

[0084] Example 1, the integral casting of the lining, is problematic because the lining thickness has already reached the design thickness. After freezing, sealing the holes affects the appearance quality of the lining, and poor sealing results in a high risk of leakage. Furthermore, the lining thickness is relatively thick, and if the drilling is skewed, additional drilling is required, which is difficult. Therefore, Example 2 was an improvement.

[0085] The difference between Example 2 and Example 1 is that the overall lining is constructed in stages to solve the problems of large overall lining thickness, difficulty in drilling when additional drilling is required, and high risk of leakage. Furthermore, the later-constructed lining can serve as a waterproof barrier, improving the safety of the tunnel boring machine.

[0086] Specifically, the overall lining includes a first lining and a second lining. Step 4 involves pouring the first lining first, and then after completing the freezing construction operation in step 5, the second lining is poured. This is to solve the problem of the large thickness of the overall lining and the difficulty of drilling when additional drilling is required.

[0087] Before pouring the first lining, a first steel plate with a round hole and anchor bars is installed at the position of the installed freezing hole pipe. After freezing is completed, the first steel plate is welded and sealed with a second steel plate. Finally, the second lining is poured, and the second lining serves as a waterproof barrier.

[0088] Example 3

[0089] In Example 2, after all the shield cylinders, shield beams, and shield ribs have been removed, the most dangerous stage, with a safety factor of 4.598, occurs during the period when all the shield cylinders are retracted, dismantled, and all shield beams and ribs are cut off. During this stage, the force transmission path of the shield changes; there is a risk of instability before the inner lining is poured.

[0090] Therefore, in Implementation Example 3, the shield cylinders are dismantled in groups, the shield beams and shield ribs corresponding to the shield cylinders are cut off, and the optimal thickness of the first lining is calculated to ensure construction stability while facilitating construction.

[0091] Step 3 involves dismantling the four sets of shield tunneling cylinders, cutting off the four sets of shield tunneling beams and ribs corresponding to the cylinders, and then dismantling the second set of cylinders and pouring the next set of linings, continuing this process in sections until completion. The first lining is poured into a ring shape. This ensures that the force transmission path of the water and soil pressure in front of the tunnel boring machine remains unchanged. The lining supports and strengthens the shield body, thus ensuring its stability and facilitating the stress on the anti-backlash device.

[0092] Furthermore, both the tunnel segments and the integral lining are made of concrete, utilizing the thermal insulation properties of concrete to eliminate the need for refrigeration pipes. The purpose of refrigeration pipes is to prevent the high temperatures generated during operations inside the shield (welding, cutting, etc.) from affecting the frozen soil on the outside of the shield. If the frozen soil adjacent to the shield melts due to temperature increases, a water seepage channel will be created between the outside of the shield and the soil, a very dangerous situation. Therefore, refrigeration pipes are installed to prevent this from happening, ensuring that the high temperatures inside the shield do not affect the frozen soil on the outside. The integral lining eliminates the need for refrigeration pipes, fully utilizing the thermal insulation properties of the concrete lining itself.

[0093] The presence of an integral lining eliminates the need for refrigeration pipes, as the concrete itself provides insulation.

[0094] Furthermore, since the stiffness of the concrete segment is 15 times that of the shield shell, the large stiffness difference will make the anti-reverse steel plate connecting the segment and the shield shell unfavorable to the stress. If there is an incremental load from the outside, the deformation of the segment will be much smaller than that of the shield shell. In this case, the anti-reverse device is at risk of shear failure. Therefore, the shield shell and the first inner lining are treated as a combination. The stiffness of the combination and the shield segment are set to be consistent. This is beneficial to the anti-reverse steel plate while strengthening the shield shell during construction, thereby solving for the optimal thickness of the first inner lining.

[0095] A further preferred method for determining the optimal thickness of the first liner includes the following steps:

[0096] Step 4.1: Based on stiffness equivalence, the shield shell in the composite structure is equivalent to a first inner liner of the same thickness, such as... Figure 6 As shown, the equivalent formula is as follows:

[0097] A s ′E c1 =A s E S

[0098] Among them, A S 'A' represents the area of ​​the shield shell after it is equivalent to the first inner liner. S E represents the actual area of ​​the shield before equivalence. c1 E represents the elastic modulus of the first liner. s This represents the elastic modulus of the shield.

[0099] Among them, A S 'and A S Refer to the following formulas respectively:

[0100] A′ s =b′×h s

[0101] A S =b×h s

[0102] Where b' represents the length of the shield shell after it is equivalent to the first inner liner, b represents the length of the shield shell before it is equivalent, and h s This indicates the shield thickness. Here, we take the actual shield thickness as 80mm, ensuring the equivalent shield thickness remains unchanged before and after.

[0103] Substituting into the calculation, we get

[0104]

[0105] Where Es is taken as the elastic modulus of Q355 steel, E c1 Take the elastic modulus of C60 concrete.

[0106]

[0107] Due to E s >E c1 If the length b' of the shield shell after being equivalent to the first inner liner is greater than the length b of the shield shell before being equivalent to the first inner liner, then the equivalent combined body is a T-shaped structure, or simply an equivalent T-shaped section.

[0108] Therefore, when b is 1m in length, b' is 5.83m.

[0109] Step 4.2: Calculate the ordinate of the centroid of the equivalent T-section:

[0110]

[0111] Where y represents the ordinate of the centroid of the equivalent T-section, and A c1 h represents the area of ​​the first lining. c1 A represents the thickness of the first liner. c This indicates the area of ​​the tunnel lining segments.

[0112] Step 4.3: Calculate the moment of inertia of the centroid of the equivalent T-section:

[0113]

[0114] Among them, I Z The moment of inertia of the centroid of the equivalent T-section, ys represents the ordinate of the section corresponding to the equivalent rear shield shell relative to its centroid, i.e., h s / 2,y c1 This represents the ordinate of the section corresponding to the first lining relative to its centroid, i.e., h. c1 / 2;

[0115] Step 4.4: Construct the stiffness equations for the equivalent T-section and shield segments, and substitute them into the equation for I in Step 3. Z Solve for h c1 :

[0116] E Z I Z =ηE C I C

[0117] Where η represents the stiffness reduction factor, because shield tunnel segments are usually pieced together, resulting in a reduction in stiffness compared to a complete ring of segments. Therefore, a stiffness reduction factor η is introduced, with η ranging from 0.7 to 0.8. C E represents the moment of inertia of the tunnel lining segments. c E represents the elastic modulus of a tunnel segment. Z Let E represent the elastic modulus of the equivalent T-section. Since the equivalent T-section is equivalent to concrete, which is the same material as the tunnel lining segment, then E... Z =E c Thus, h can be obtained.c1 =380mm.

[0118] This invention proposes a method for constructing the shield lining during underwater docking. The above embodiments are only for illustrating the technical concept and features of this invention, and are intended to enable those skilled in the art to understand the content of this invention and implement it accordingly. They should not be construed as limiting the scope of protection of this invention. All equivalent changes or modifications made according to the spirit and essence of this invention should be covered within the scope of protection of this invention.

Claims

1. A method for constructing the shield body lining during underwater docking, characterized in that, Includes the following steps: Step 1: The two tunnel boring machines (TBMs) tunnel towards each other and connect at the bottom of the river. After that, the TBM cylinders are retracted, and a ring of anti-reverse plates is welded onto the shield segments of the last stage of the tunneling process on each of the two TBMs. The height of the anti-reverse plates is less than the thickness of the shield segments. Step 2: Cast a partial inner lining ring beam at the corresponding position of the anti-reverse plate. The inner arc surface of the partial inner lining ring beam is on the same plane as the inner arc surface of the shield segment. Step 3: Dismantle the shield cylinders in batches and simultaneously cut off the shield beams and internal ribs of the shield machine at the corresponding locations; the cylinders are dismantled and cut off in batches of 4 sets. Step 4: After each batch of hydraulic cylinders and corresponding structures are removed, immediately install the freezing orifice pipe at the corresponding shield section of the tunnel boring machine and pour the first inner lining, so that the freezing orifice pipe is pre-embedded in the first inner lining and its end is located on the outside of the first inner lining; repeat this process until the first inner lining is poured into a ring. Step 5: Install freezing pipelines through freezing hole openings to carry out freezing construction. After the freezing construction is completed, seal the freezing holes. Step 6: After the freezing construction is completed, the freezing hole pipe is sealed, and then the second inner lining is poured on the basis of the first inner lining. The first inner lining and the second inner lining together form an integral inner lining.

2. The method for constructing the shield lining during docking at the bottom of a river as described in claim 1, characterized in that: Step 4: Before pouring the overall lining, weld studs to ensure that the overall lining and the shield form a whole, and that the overall lining and the shield form a composite component that shares the load.

3. The method for constructing the shield lining during docking at the bottom of a river as described in claim 2, characterized in that: Within a one-meter ring width, studs with a diameter of 25mm are selected. Within a contact area of ​​50.24 square meters, three studs are set per square meter, for a total of 151 studs. The longitudinal spacing is 0.333 meters and the circumferential spacing is 0.5 meters, which ensures the shear capacity of the studs while reducing the welding difficulty.

4. The method for constructing the shield lining during docking at the bottom of a river as described in claim 1, characterized in that: Step 5: Grouting is performed inside the frozen orifice using a one-way ball valve, and then the orifice is sealed by welding with a steel plate to complete the freezing construction.

5. The method for constructing the shield lining during docking at the bottom of a river as described in claim 1, characterized in that: Before pouring the first lining, a first steel plate with a round hole and anchor bars is installed at the position of the installed freezing hole pipe. After freezing is completed, the first steel plate is welded and sealed with a second steel plate. Finally, the second lining is poured, and the second lining serves as a waterproof barrier.

6. The method for constructing the shield lining during docking at the bottom of a river as described in claim 1, characterized in that: The entire inner lining is made of concrete, which utilizes the thermal insulation properties of concrete to avoid the need for laying frozen pipes during construction, thus facilitating construction and reducing the amount of work required.

7. The method for constructing the shield lining during docking at the bottom of a river as described in claim 6, characterized in that: The shield shell and the first inner lining are treated as a combined unit, and the stiffness of the combined unit and the shield segments are set to be consistent to ensure the stress on the anti-backflow plate during construction, thereby solving for the optimal thickness of the first inner lining.

8. The method for constructing the shield lining during docking at the bottom of a river as described in claim 7, characterized in that, The optimal thickness of the first liner is determined by the following steps: Step 4.1: Based on stiffness equivalence, the shield shell in the composite is equivalent to a first inner liner of the same thickness, then: ； Among them, A S ’ A represents the area of ​​the shield after it has been converted into the first liner. S E represents the actual area of ​​the shield before equivalence. c1 E represents the elastic modulus of the first liner. s This represents the elastic modulus of the shield. Among them, A S ’ and A S Refer to the following formulas respectively: ； ； Where b' represents the length of the shield shell after it is equivalent to the first inner liner, b represents the length of the shield shell before it is equivalent, and h s This indicates the shield thickness; the equivalent shield thickness remains unchanged. Substituting into the calculation, we get ； Due to E s >E c1 If the length b' of the shield shell after being equivalent to the first inner liner is greater than the length b of the shield shell before being equivalent to the first inner liner, then the equivalent combined body is a T-shaped structure, or simply an equivalent T-shaped section. Step 4.2: Calculate the ordinate of the centroid of the equivalent T-section: ； Where y represents the ordinate of the centroid of the equivalent T-section, and A c1 h represents the area of ​​the first lining. c1 A represents the thickness of the first liner. c This indicates the area of ​​the tunnel lining segments. Step 4.3: Calculate the moment of inertia of the centroid of the equivalent T-section: ； Among them, I Z The moment of inertia of the centroid of the equivalent T-section, y s The ordinate of the equivalent rear shield shell section relative to its centroid is represented by h. s / 2,y c1 This represents the ordinate of the section corresponding to the first lining relative to its centroid, i.e., h. c1 / 2; Step 4.4: Construct the stiffness equations for the equivalent T-section and shield segments, and solve for h by combining steps 4.2 and 4.

3. c1 The stiffness equation is as follows: ； Where η represents the stiffness reduction factor, I C E represents the moment of inertia of the tunnel lining segments. c E represents the elastic modulus of a tunnel segment. Z This represents the elastic modulus of the equivalent T-section.

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