Arrangement and dynamic support method for a shield tunneling jumbo

Abstract

This invention relates to an arrangement structure and dynamic support method for a tunnel boring machine (TBM) trolley. The support method defines the initial, starting, peak, and ending states of the TBM cutterhead. During the jack support process, the support force provided by the TBM cutterhead is zero in the initial and ending states; the support force provided in the initial state is the initial support force; the support force provided in the peak state is the peak support force; and the support force is calculated using a linear interpolation method in other positions. Compared with existing technologies, this invention offers advantages such as a non-constant jack support force, greater flexibility compared to the constant support force currently used in engineering, ensuring that the trolley support force matches the variation in additional pressure caused by subsequent tunnel boring machine construction, and avoiding quality problems such as joint opening and water seepage, segment convergence deformation, and cracking caused by excessive or insufficient support force.

Description

Technical Field

[0001] This invention relates to shield tunnel construction, and in particular to an arrangement structure and dynamic support method for a shield tunnel trolley. Background Technology

[0002] When the clearance between two parallel shield tunnels is less than one tunnel outer diameter, the thrust generated by the cutterhead and the grouting pressure generated by the synchronous grouting at the tail of the shield will create significant additional pressure on the surface of the preceding tunnel during the construction of the subsequent tunnel. This can lead to cross-sectional convergence deformation of the preceding tunnel, and even joint seepage and segment cracking, seriously threatening the construction quality and operational safety of the shield tunnel. For shield tunnels with an ultra-small horizontal clearance of no more than 0.3 tunnel outer diameter, it is necessary to temporarily install a trolley in the preceding tunnel during the construction of the subsequent tunnel to provide additional support and share the additional pressure during the construction of the subsequent tunnel.

[0003] Currently, the support trolleys used in the project all employ constant support force. However, the additional pressure borne by the preceding tunnel is not constant. When the constant support force is greater than the additional pressure borne by the preceding tunnel, it will cause the preceding tunnel to be pushed outward, resulting in loose joints and leakage. When the constant support force is less than the additional pressure borne by the preceding tunnel, no effective internal support is formed, which will cause the preceding tunnel to undergo convergence deformation exceeding the limit standard, or even irreversible consequences such as segment cracking. Thus, the support trolleys have failed to effectively protect the preceding tunnel.

[0004] Therefore, how to rationally arrange the shield tunnel trolleys and provide a dynamic support method is a technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology, where the supporting force provided by the support trolley is not adapted to the different pressures borne by the shield tunnel, and to provide a shield tunnel trolley arrangement structure and dynamic support method.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] According to one aspect of the present invention, a shield tunnel trolley arrangement structure is provided. Multiple sets of jacks are provided on the outer surface of the trolley at different positions. A cross-section is taken at the position where a set of jacks is located on the trolley. The part of the outer contour line of the cross-section where there is a gap between the trolley and the shield tunnel is set as the jack arrangement area. In the jack arrangement area, the position of the trolley closest to the top of the tunnel is taken as the starting point. Starting from the starting point, a jack is set at fixed angles.

[0008] As a preferred technical solution, the fixed angle is 45°, one vertical jack is set to support the top of the tunnel; two horizontal jacks are set to support the arch waists on both sides of the tunnel respectively; four oblique jacks are set to support the arch shoulders and arch feet on both sides of the tunnel respectively; a group of multiple jacks are distributed in a cross-section of the trolley in a star shape.

[0009] According to another aspect of the present invention, a dynamic support method is provided using a shield tunnel trolley arrangement structure, wherein the shield tunnel includes a preceding tunnel and a following tunnel with the same outer diameter, the net distance between the preceding and following tunnels being less than 0.3 times the outer diameter of the shield tunnel; a trolley is provided inside the preceding tunnel, and multiple sets of jacks on the trolley provide support force at multiple locations in the preceding tunnel; a shield machine is located at one end of the following tunnel, and a shield machine cutterhead is provided on the shield machine; the length of the shield machine is a first length; the dynamic support method includes:

[0010] The initial state is defined as the shield machine cutterhead arriving at the cross section where a set of jacks on the trolley is located; the starting state is the shield machine cutterhead retracting by the first length from the initial state; the peak state is the shield machine cutterhead advancing by the first length from the initial state; and the ending state is twice the length the shield machine cutterhead has advanced from the initial state.

[0011] During the jack support process, the support force provided by the tunnel boring machine cutterhead is zero when it is in the initial and final states; the support force provided when the cutterhead is in the initial state is the initial support force; and the support force provided when the cutterhead is in the peak state is the peak support force.

[0012] When the cutterhead of the tunnel boring machine is in other positions, the support force is calculated using linear interpolation.

[0013] As a preferred technical solution, the jacks in the same group set at different positions provide different supporting forces: the vertical jacks provide a supporting force of F1, the horizontal jacks provide a supporting force of F2, and the inclined jacks provide a supporting force of F3, with F1>F3>F2.

[0014] As a preferred technical solution, the peak support force provided by the vertical jack is F. f1 The peak support force provided by the horizontal jack is F. f2 The peak support force provided by the inclined jack is F. f3 F f1 :F f3 :F f2 = 8:4:1.

[0015] As a preferred technical solution, the ratio of the distance between the top of the shield tunnel and the ground to the outer diameter of the shield tunnel is the relative burial depth, and the ratio of the net distance between the preceding and following tunnels to the outer diameter of the shield tunnel is the relative net distance; different relative burial depths and relative net distances result in different supporting forces provided by the jacks.

[0016] As a preferred technical solution, the supporting force increases with the increase of relative burial depth; the supporting force decreases with the increase of relative net distance.

[0017] As a preferred technical solution, when the relative net distance is the same, the value of the supporting force is a linear function of the relative burial depth.

[0018] As a preferred technical solution, when the relative burial depths are the same, the initial supporting force provided by the jacks in the vertical direction is F. c1 The initial supporting force provided by the horizontal jack is F. c2 The initial support force provided by the inclined jack is F. c3 When the relative net distance is 0.1, F c1 :F c3 :F c2 = 5:3:1; when the relative net distance is 0.2, F c1 :F c3 :F c2 = 3:2:0; when the relative net distance is 0.3, F c1 :F c3 :F c2 =2:1:0.

[0019] As a preferred technical solution, the jack provides a maximum supporting force of 120kN and a control accuracy of 5kN.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1) The jack support force of the trolley in the tunnel of the present invention is not a constant value. Compared with the constant support force used in the current project, it is more flexible. As the position of the shield machine cutterhead moves forward, it is constantly adjusted with the change of the distance between the cutterhead and the cross section where the trolley is located. This ensures that the size of the trolley support force matches the change law of the additional pressure caused by the subsequent tunnel shield construction, and avoids quality problems such as joint opening and water seepage, segment convergence deformation and cracking caused by excessive or insufficient support force.

[0022] 2) The supporting force of each jack on the trolley of this invention is not the same, which is more in line with actual needs compared with the single supporting force used in current engineering. At the same time, the supporting force of the jack in the vertical direction is the largest, followed by the jack in the diagonal direction, and the supporting force of the jack in the horizontal direction is the smallest. This is consistent with the deformation trend of the shield tunnel, avoiding excessive redundancy of the supporting force of the hydraulic jacks on the trolley and reducing the performance requirements of the jacks. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the jack arrangement of the shield tunnel trolley of the present invention;

[0024] Figure 2 This is a schematic diagram illustrating the variation of the trolley support force with distance in this invention;

[0025] Figure 3 This diagram illustrates the variation of the jack support axial force and the subsequent position of the tunnel cutterhead when the relative burial depth is 1 and the relative clearance is 0.1.

[0026] Figure 4 This diagram illustrates the variation of the jack support axial force and the subsequent position of the tunnel cutterhead when the relative burial depth is 1 and the relative clearance is 0.2.

[0027] The numbers in the diagram are as follows:

[0028] 1. Pre-tunnel, 2. Tunnel boring machine (TBM), 21. TBM cutterhead, 3. Subsequent tunnel, 4. Trolley, 5. Ground. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] The purpose of this invention is to ensure the support effect of the trolley 4 in shield tunnels with ultra-small horizontal clearance. Based on the characteristics of the additional pressure changes generated on the preceding tunnel 1 during the construction of the subsequent tunnel 3, this invention proposes a shield tunnel trolley arrangement structure and dynamic support method that is adapted to the subsequent shield tunnel construction process. This invention, based on the vertical distance between the tunnel and the ground 5, the horizontal clearance between the preceding and following shield tunnels, the tunnel outer diameter, and the longitudinal distance between the shield machine cutterhead 21 and the cross-section where the trolley 4 is located in the preceding shield tunnel (the longitudinal direction is the tunnel axis direction, with the shield machine's excavation direction as forward, i.e., positive, and the opposite as backward, i.e. negative); combined with the variation law of additional pressure, additional convergence deformation, and additional internal force of the preceding shield tunnel caused by the following shield tunnel during the construction of shield tunnels with ultra-small horizontal clearance, and based on the requirements for deformation and bearing capacity control, proposes a dynamic support parameter setting method consisting of four key states and two sets of key support forces. This effectively avoids the problem of excessive support force of trolley 4 in the early and late stages of subsequent shield tunnel construction and insufficient support force of trolley 4 in the middle stage of construction, providing dynamically matched support force for the preceding shield tunnel, effectively controlling the convergence deformation of the preceding shield tunnel, and avoiding quality problems such as deformation encroachment, joint seepage, and structural cracking.

[0031] Example 1

[0032] like Figure 1 As shown, the present invention provides an arrangement structure for a shield tunnel trolley. The outer surface of the trolley 4 is provided with multiple sets of jacks, each set of jacks containing multiple jacks. A cross-section is taken at the position where a set of jacks is located on the trolley 4. The part of the outer contour line of the cross-section where there is a gap between the trolley 4 and the shield tunnel is set as the jack arrangement area. In the jack arrangement area, the position of the trolley 4 closest to the top of the tunnel is taken as the starting point. Starting from the starting point, a jack is set every 45°. Among them, there is one vertical jack supporting the top of the tunnel; two horizontal jacks supporting the arch waists on both sides of the tunnel respectively; and four diagonal jacks supporting the arch shoulders and arch feet on both sides of the tunnel. The seven jacks are distributed in a star shape on the cross-section of the trolley 4.

[0033] Example 2

[0034] This invention provides a dynamic support method for a shield tunnel trolley 4. The shield tunnel includes a preliminary tunnel 1 and a subsequent tunnel 3 with the same outer diameter. The net distance between the preliminary tunnel 1 and the subsequent tunnel 3 is less than 0.3 times the outer diameter of the shield tunnel. The preliminary tunnel 1 is equipped with a trolley 4, and the jacks of the trolley 4 provide a supporting force F to the preliminary tunnel 1. The subsequent tunnel 3 is equipped with a shield machine 2, and the shield machine 2 is equipped with a shield machine cutterhead 21.

[0035] The length of the tunnel boring machine is defined as the first length; the initial state l0 is defined as the cross section where the tunnel boring machine cutterhead 21 arrives at the cross section where the first tunnel 1 vehicle 4 and a set of jacks are located; the starting state l4 is the first length that the tunnel boring machine cutterhead 21 retreats from the initial state; the peak state l5 is the first length that the tunnel boring machine cutterhead 21 advances from the initial state; and the ending state l6 is twice the first length that the tunnel boring machine cutterhead 21 advances from the initial state. Figure 1 The dashed line in the middle shows the intersection of the cross section where the trolley 4 is located and the subsequent tunnel 3.

[0036] like Figure 2 As shown, during the support process of this set of jacks, the support force provided is zero when the distance between the shield machine cutterhead 21 and the cross section where the trolley 4 is located is in the initial and final states; when the distance between the shield machine cutterhead 21 and the cross section where the trolley 4 is located is in the initial state, the support force provided is the initial support force F. c When the distance between the cutterhead 21 of the tunnel boring machine and the cross section where the trolley 4 is located is at its peak, the supporting force provided is the peak supporting force F. f When the distance between the cutterhead 21 of the tunnel boring machine and the cross section where the trolley 4 is located is other than the distance between the two sections, the support force is calculated by linear interpolation.

[0037] The ratio of the distance between the top of the shield tunnel and the ground surface (5) to the outer diameter of the shield tunnel is the relative burial depth; the ratio of the net distance between the preceding tunnel (1) and the following tunnel (3) to the outer diameter of the shield tunnel is the relative net distance. Different relative burial depths and relative net distances result in different support forces provided by the jacks. The support force increases with increasing relative burial depth and decreases with increasing relative net distance. When the relative net distance is the same, the support force is a linear function of the relative burial depth.

[0038] Based on field tests, experimental data were obtained through extensive three-dimensional numerical simulations and centrifugal model tests after verification. Taking the case of relative burial depth h / D=1 and relative net distances d / D=0.1 and 0.2 respectively as examples, the variation law of jack support axial force with the position of shield machine cutterhead 21 determined by three-dimensional numerical simulation is as follows: Figure 3 and Figure 4 As shown, the axial force of the vertical support is the largest, with peak values ​​of 105kN and 77kN respectively; the axial force of the diagonal support is the second largest, with peak values ​​of approximately 62kN and 44kN respectively; and the axial force of the horizontal support is the smallest, with peak values ​​of only 9kN and 6kN respectively. The support axial force represents the axial force that the jack needs to apply. Considering that the vertical jack has a greater influence on the control effect, the axial force is taken as a slightly larger value, and the other values ​​are rounded down slightly to obtain the recommended values ​​shown in Table 1.

[0039] In Table 1, the supporting forces provided by jacks positioned at different locations within the same group vary. The supporting force provided by the vertical jack is F1, the horizontal jack is F2, and the inclined jack is F3, with F1 > F3 > F2. The peak supporting force provided by the vertical jack is F... f1 The peak support force provided by the horizontal jack is F. f2 The peak support force provided by the inclined jack is F. f3 F f1 :F f3 :F f2 = 8:4:1. When the relative burial depth is the same, the initial support force provided by the vertical jack is F. c1 The initial supporting force provided by the horizontal jack is F. c2 The initial support force provided by the inclined jack is F. c3 When the relative net distance is 0.1, F c1 :F c3 :F c2 = 5:3:1; when the relative net distance is 0.2, F c1 :F c3 :F c2 = 3:2:0; when the relative net distance is 0.3, F c1 :F c3 :F c2 =2:1:0.

[0040] Table 1. Values ​​of initial and maximum support forces

[0041]

[0042] Apply the above to the following construction situations:

[0043] The shield tunnel has an outer diameter D of 6.2m, a segment width of 1.2m per ring, and a top burial depth l1 of 11.5m, all within a silty clay layer. The horizontal clearance l2 between the up and down tunnels is 1.82m, with a relative burial depth of 11.5 / 6.2 = 1.85m and a relative clearance of 1.82 / 6.2 = 0.29m. The first tunnel, Tunnel 1, is excavated first and received at the reserved station. One month later, the subsequent tunnel, Tunnel 3, is excavated to the reserved station and received and removed. The shield machine has an excavation diameter of 6.44m, a length l3 of 8.86m, and a thrust F generated by the shield machine cutterhead. t It stabilizes between 0.134 and 0.209 MPa, approximately 1.2 times the static lateral earth pressure. The grouting pressure F at the shield tail of the tunnel boring machine... z The pressure remained stable between 0.25 and 0.32 MPa, approximately 1.5 times the groundwater pressure. The tunnel boring machine's construction parameters were within the standard range.

[0044] Trolley 4 is installed with a support cross-section within each ring of the first tunnel segment. Each hydraulic jack has a maximum allowable support force of 120 kN and a control precision of 5 kN. The hydraulic jacks apply support force to the first tunnel segment, sharing the thrust F generated by the tunnel boring machine cutterhead during the construction of the subsequent tunnel 3. t and shield tail grouting pressure F z Additional pressure applied to the first tunnel 1.

[0045] During the tunneling process of shield machine 2, the support force of each set of support jacks on the trolley 4 is set and dynamically adjusted according to the distance between the shield machine cutterhead 21 and the cross section where the support jacks are located. Given the shield machine length l3, for ease of on-site construction management, the initial state l4 is calculated to be the first 8 ring segments before the shield machine cutterhead reaches the cross section, the peak state l5 is the last 8 ring segments after the shield machine cutterhead reaches the cross section, and the final state l6 is the last 15 ring segments after the shield machine cutterhead reaches the cross section. Based on a relative burial depth of 1.85 and a relative clearance of 0.29, and approximating the cases in Table 1 with a relative burial depth of 2.0 and a relative clearance of 0.3, the initial support forces of the vertical, inclined, and horizontal jacks are taken as 20kN, 10kN, and 0kN, respectively, and the maximum support forces of the vertical, inclined, and horizontal jacks are taken as 80kN, 40kN, and 10kN, respectively.

[0046] Taking a set of support jacks installed on the 620th ring trolley 4 of the first tunnel as an example, since both tunnels have curves, the tunnel lengths differ due to the different curve radii. At this time, the 620th ring of the first tunnel and the 634th ring of the subsequent tunnel are on the same cross section. Therefore, when the subsequent tunnel 3 is excavating the 626th ring (8 rings before the 634th ring), the support jacks on the 620th ring trolley 4 of the first tunnel are ready to apply support force. When the subsequent shield tunnel is excavating the 634th ring, the support forces of the vertical, inclined, and horizontal jacks on the 620th ring trolley 4 of the first tunnel reach 20kN, 10kN, and 0kN, respectively; when the subsequent shield tunnel is excavating the 642nd ring (8 rings after the 634th ring), the support forces of the vertical, inclined, and horizontal jacks on the 620th ring trolley 4 of the first tunnel reach 80kN, 40kN, and 10kN, respectively. When the tunnel boring machine reached the 649th ring, which is 15 rings after the 634th ring, the supporting force of the jacks on the 4th trolley of the 620th ring of the first tunnel was completely removed.

[0047] When the subsequent shield tunnel continues to excavate to the 650th ring and beyond, the trolley 4 of the 620th ring of the preceding tunnel 1 can be removed. This can be achieved either by disassembling trolley 4 and reassembling it at the front, or by moving trolley 4 synchronously with the shield machine 2, thus saving on the amount of work involved in trolley 4. When the distance l supported by trolley 4 in the preceding tunnel 1 is within the range of the initial state l4 to the final state l6, the supporting force of the hydraulic jacks in that section must always meet the specified dynamic supporting parameter requirements. The supporting force provided by the jacks should not be temporarily reduced due to the movement of trolley 4.

[0048] Monitoring of the above construction progress revealed that during the construction of the subsequent tunnel 3, the convergence deformation of the 620th ring of the preceding tunnel 1 increased by 9.3 mm, with a relative convergence deformation of 9.3 / 6200 = 1.5‰. This meets the control requirements of the "Technical Guidelines for Design and Construction of Small-Clearance Horizontal Tunnels in Rail Transit" regarding "the relative convergence deformation of the cross-section of the preceding shield tunnel still under construction due to small-clearance shield tunnel construction not exceeding ±0.6%" and "the support force of the 4-jack jack on the trolley not exceeding the design value." No joint leakage or segment cracking issues occurred in the preceding shield tunnel, ensuring the quality and safety of the ultra-small horizontal clearance shield tunnel project.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method of dynamic support of a shield tunnel jumbo, characterized in that, The shield tunnel includes a preliminary tunnel (1) and a subsequent tunnel (3) with the same outer diameter, and the net distance between the preliminary tunnel (1) and the subsequent tunnel (3) is less than 0.3 times the outer diameter of the shield tunnel; a trolley (4) is provided in the preliminary tunnel (1), and multiple sets of jacks on the trolley (4) provide support for multiple positions in the preliminary tunnel (1); a shield machine (2) is located at one end of the subsequent tunnel (3), and a shield machine cutterhead (21) is provided on the shield machine (2); the length of the shield machine is the first length; the dynamic support method includes: The initial state is defined as the shield machine cutterhead (21) arriving at the cross section where a set of jacks on the trolley (4) are located; the starting state is the shield machine cutterhead (21) retreating by the first length from the initial state; the peak state is the shield machine cutterhead (21) advancing by the first length from the initial state; and the ending state is twice the length that the shield machine cutterhead (21) has advanced from the initial state. During the jack support process, the support force provided by the shield machine cutterhead (21) is zero when it is in the initial state and the end state; the support force provided by the shield machine cutterhead (21) is the initial support force when it is in the initial state; and the support force provided by the shield machine cutterhead (21) is the peak support force when it is in the peak state. When the cutterhead (21) of the tunnel boring machine is in other positions, the support force is calculated by linear interpolation. The jacks in the same group, set in different positions, provide different supporting forces. The vertical jacks provide a supporting force of F1, the horizontal jacks provide a supporting force of F2, and the inclined jacks provide a supporting force of F3, with F1>F3>F2. The ratio of the distance between the top of the shield tunnel and the ground (5) to the outer diameter of the shield tunnel is the relative burial depth, and the ratio of the net distance between the first tunnel (1) and the second tunnel (3) to the outer diameter of the shield tunnel is the relative net distance; the jack provides different support forces for different relative burial depths and relative net distances. The initial support force provided by the jack in the vertical direction is F c1 , the initial support force provided by the jack in the horizontal direction is F c2 , and the initial support force provided by the jack in the oblique direction is F c3 ; when the relative net distance is 0.1, F c1 : F c3 : F c2 = 5:3:1; when the relative net distance is 0.2, F c1 : F c3 : F c2 = 3:2:0; when the relative net distance is 0.3, F c1 : F c3 : F c2 = 2:1:

0.

2. The dynamic support method of claim 1, wherein, The peak support force provided by the vertical jack is F f1 , the peak support force provided by the horizontal jack is F f2 , the peak support force provided by the diagonal jack is F f3 , F f1 : F f3 : F f2 = 8:4:

1.

3. The dynamic support method of claim 2, wherein, The supporting force increases with the increase of relative burial depth; the supporting force decreases with the increase of relative net distance.

4. The dynamic support method of claim 2, wherein, When the relative clearance is the same, the value of the supporting force is a linear function of the relative burial depth.

5. The dynamic support method of claim 1, wherein, The jack provides a maximum support force of 120kN and a control accuracy of 5kN.

6. The dynamic support method of claim 1, wherein, The arrangement structure of the shield tunnel trolley is as follows: multiple sets of jacks are provided on the outer surface of the trolley (4) at different positions. A cross section is taken at the position where a set of jacks is provided on the trolley (4). The part of the cross section with a gap between the trolley (4) and the shield tunnel is set as the jack arrangement area. In the jack arrangement area, the position of the trolley (4) closest to the top of the tunnel is taken as the starting point. Starting from the starting point, a jack is set at fixed angles.

7. The dynamic support method of claim 6, wherein, The fixed angle is 45°. One vertical jack is set to support the top of the tunnel; two horizontal jacks are set to support the arches on both sides of the tunnel respectively. Four inclined jacks are set up to support the arch shoulders and arch feet on both sides of the tunnel respectively; a group of jacks are distributed in a cross shape on the cross section of the trolley (4).

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