Arrangement structure and dynamic supporting method of shield tunnel trolley

Abstract

The invention relates to an arrangement structure of a shield tunnel trolley and a dynamic supporting method. The supporting method comprises the steps that the initial state, the initial state, the peak value state and the end state of the shield tunneling machine cutterhead are defined; in the jack supporting process, when the shield tunneling machine cutterhead is in an initial state and an end state, the provided supporting force is zero; in the initial state, the provided supporting force is initial supporting force; in the peak state, the provided supporting force is peak supporting force; and the supporting force is calculated by adopting a linear difference value mode at other positions. Compared with the prior art, the supporting force of the jack is not a constant value and is more flexible compared with constant supporting force adopted in current engineering, and it is guaranteed that the magnitude of the supporting force of the trolley is matched with an additional pressure change rule caused by following tunnel shield construction; and the quality problems of seam opening and water seepage, segment convergence deformation, cracking and the like caused by too large or too small supporting force are avoided.

Description

Technical Field

[0001] The invention relates to shield tunnel construction, and in particular to an arrangement structure and a dynamic support method of a shield tunnel trolley. Background Art

[0002] When the clearance between two horizontally parallel shield tunnels is less than 1 times the outer diameter of the tunnel, during the construction of the subsequent tunnel, the thrust formed by the cutterhead and the grouting pressure formed by the synchronous grouting of the shield tail will form a large staged additional pressure on the surface of the leading tunnel, causing the cross-section of the leading tunnel to converge and deform, and even joint seepage and segment cracking, which seriously threatens the construction quality and operational safety of the shield tunnel. For shield tunnels with ultra-small horizontal clearance of no more than 0.3 times the outer diameter of the tunnel, a trolley must be temporarily set up in the leading tunnel during the construction of the subsequent tunnel to provide additional support for the leading tunnel and share the staged additional pressure in the construction of the subsequent tunnel.

[0003] At present, the supporting trolleys of the project all adopt constant supporting force, but the additional pressure borne by the leading tunnel is not constant. When the constant supporting force is greater than the additional pressure borne by the leading tunnel, the leading tunnel will be stretched outward, the joints will loosen and cause water leakage; when the constant supporting force is less than the additional pressure borne by the leading tunnel, no effective internal support will be formed, resulting in convergence deformation of the leading tunnel exceeding the limit standard, and even irreversible consequences such as cracking of the pipe segments, and the supporting trolley fails to effectively protect the leading tunnel.

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

[0005] The purpose of the present invention is to provide a layout structure and dynamic support method of a shield tunnel trolley in order to overcome the defect in the prior art that the supporting force provided by the supporting trolley is not suitable for the different pressures borne by the shield tunnel.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to one aspect of the present invention, a layout structure of a shield tunnel trolley is provided, wherein a plurality of groups of jacks located at different positions are provided on the outer surface of the trolley, a cross section of the position where the trolley is provided with a group of jacks is cut, and a portion of the outer contour line of the cross section where there is a gap between the trolley and the shield tunnel is set as a jack layout area, and within the jack layout area, the position of the trolley closest to the tunnel top is taken as the starting point, and a jack is set at every fixed angle starting from the starting point.

[0008] As an optimal technical solution, the fixed angle is 45°, and a 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-shaped pattern on the cross section of the trolley.

[0009] According to another aspect of the present invention, a dynamic support method using an arrangement structure of a shield tunnel trolley is provided, wherein the shield tunnel comprises a leading tunnel and a trailing tunnel having the same outer diameter, and the clear distance between the leading tunnel and the trailing tunnel is less than 0.3 times the outer diameter of the shield tunnel; a trolley is provided in the leading tunnel, and multiple groups of jacks of the trolley provide support force for multiple positions of the leading tunnel; a shield machine is located at one end of the trailing 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 comprises:

[0010] The initial state is defined as the cross section where the shield machine cutterhead reaches a set of jacks on the trolley; the starting state is the shield machine cutterhead retreating the first length from the initial state; the peak state is the shield machine cutterhead advancing the first length from the initial state; and the ending state is twice the shield machine cutterhead advancing the first length from the initial state.

[0011] During the jack support process, when the shield machine cutterhead is in the starting state and the ending state, the support force provided is zero; when the shield machine cutterhead is in the initial state, the support force provided is the initial support force; when the shield machine cutterhead is in the peak state, the support force provided is the peak support force;

[0012] When the shield machine cutterhead is located at other positions, the support force is calculated using the linear difference method.

[0013] As a preferred technical solution, the same group of jacks arranged at different positions provide different supporting forces. The supporting force provided by the jacks in the vertical direction is F 1 , the support force provided by the horizontal jack is F 2 , the supporting force provided by the inclined jack is F 3 , F 1 >F 3 >F 2 .

[0014] As a preferred technical solution, the peak support force provided by the jack in the vertical direction 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 clear distance between the preceding tunnel and the succeeding tunnel to the outer diameter of the shield tunnel is the relative clear distance; different relative burial depths and relative clear distances provide different supporting forces for 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 clear distance.

[0017] As a preferred technical solution, when the relative clear 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 depth is the same, the initial support force provided by the jack in the vertical direction is F c1 , the initial support force provided by the horizontal jack is F c2 , the initial support force provided by the inclined jack is F c3 ; When the relative clearance is 0.1, F c1 : F c3 : F c2 =5:3:1; when the relative clearance is 0.2, F c1 : F c3 : F c2 =3:2:0; when the relative clearance is 0.3, F c1 : F c3 : F c2 =2:1:0.

[0019] As a preferred technical solution, the maximum supporting force provided by the jack is 120kN, and the control accuracy is 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 advance tunnel of the present invention is not a constant value, which is more flexible than the constant support force used in current projects. In the process of the continuous forward movement of the cutterhead of the shield machine, the jack support force is continuously adjusted with the change of the distance between the cutterhead and the cross section where the trolley is located, so as to ensure that the size of the trolley support force matches the law of the additional pressure change caused by the shield construction of the subsequent tunnel, and avoid 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 of the trolley of the present invention is not the same, which is more in line with actual needs compared with the only supporting force used in current projects. At the same time, the supporting force of the jack in the vertical direction is the largest, the oblique jack is the second, and the supporting force of the jack in the horizontal direction is the smallest, which is consistent with the deformation trend of the preceding shield tunnel, avoids excessive redundancy of the supporting force of the trolley hydraulic jack, and reduces the performance requirements of the jack. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0024] Figure 2 This is a schematic diagram of the change of the supporting force of the trolley with distance according to the present invention;

[0025] Figure 3 This is a diagram showing the change of the jack support axial force and the position of the cutterhead in the subsequent tunnel when the relative buried depth is 1 and the relative clear distance is 0.1;

[0026] Figure 4 This is a diagram showing the change of the jack support axial force and the position of the cutterhead in the subsequent tunnel when the relative buried depth is 1 and the relative clear distance is 0.2 according to the present invention;

[0027] The numbers in the figure show:

[0028] 1. Advance tunnel, 2. TBM, 21. TBM cutterhead, 3. Rear tunnel, 4. Trolley, 5. Ground. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] The purpose of the present invention is to ensure the supporting effect of the trolley 4 in the shield tunnel with ultra-small horizontal clearance. Based on the characteristics of the additional pressure change on the leading tunnel 1 during the construction of the subsequent tunnel 3, an arrangement structure and a dynamic support method of the shield tunnel trolley suitable for the subsequent shield construction process are proposed. The present invention is based on the vertical distance between the tunnel and the ground 5, the horizontal clearance between the leading and trailing shield tunnels, the outer diameter of the tunnel, the longitudinal distance between the shield machine cutter head 21 and the cross section of the trolley 4 in the leading shield tunnel (the longitudinal direction is the tunnel axis direction, with the shield machine excavation direction as forward, i.e. positive, and the opposite as backward, i.e. negative); combined with the change law of the additional pressure, additional convergence deformation, and additional internal force of the leading shield tunnel caused by the trailing shield tunnel during the construction of the ultra-small horizontal clearance shield tunnel, based on the deformation and bearing capacity control requirements, a dynamic support parameter setting method consisting of four key states and two groups of key support forces is proposed, which effectively avoids the problem of excessive support force of the trolley 4 in the early and late stages of construction of the trailing shield tunnel and too small support force of the trolley 4 in the middle stage of construction, provides dynamically matched support force for the leading shield tunnel, effectively controls the convergence deformation of the leading shield tunnel, and avoids quality problems such as deformation intrusion, joint seepage, and structural cracking.

[0031] Example 1

[0032] like Figure 1 As shown, the present invention provides an arrangement structure of a shield tunnel trolley, wherein a plurality of groups of jacks are arranged on the outer surface of the trolley 4, each group of jacks comprises a plurality of jacks, a cross section of the position where the trolley 4 is provided with a group of jacks is cut, and a portion of the outer contour line of the cross section where the trolley 4 and the shield tunnel have a gap is set as a jack arrangement area, and within the jack arrangement area, a position of the trolley 4 closest to the tunnel top is taken as a starting point, and a jack is arranged every 45° from the starting point; wherein there is one jack in the vertical direction to support the tunnel top; two jacks in the horizontal direction to support the arch waists on both sides of the tunnel respectively; four oblique jacks to support the arch shoulders and arch feet on both sides of the tunnel; and seven jacks are distributed in a cross-shaped pattern on the cross section of the trolley 4.

[0033] Example 2

[0034] The present invention provides a dynamic support method for a shield tunnel trolley 4, wherein the shield tunnel comprises a leading tunnel 1 and a trailing tunnel 3 with the same outer diameter, the net distance between the leading tunnel 1 and the trailing tunnel 3 is less than 0.3 times the outer diameter of the shield tunnel, the leading tunnel 1 is provided with a trolley 4, and the jack of the trolley 4 provides a supporting force F for the leading tunnel 1; the trailing tunnel 3 is provided with a shield machine 2, and the shield machine 2 is provided with a shield machine cutter head 21.

[0035] The length of the shield machine is the first length; define the initial state l 0 The shield machine cutter head 21 arrives at the cross section where a group of jacks of the first trolley 4 are located; the initial state l4 The shield machine cutter head 21 retreats the first length from the initial state; the peak state l 5 The shield machine cutter head 21 advances the first length from the initial state; the end state l 6 It is twice the first length that the shield machine cutter head 21 advances from the initial state. Figure 1 The middle dotted line shows the intersection line between the cross section where the trolley 4 is located and the rear tunnel 3.

[0036] like Figure 2 As shown, during the support process of this group of jacks, when the distance between the shield machine cutter head 21 and the cross section where the trolley 4 is located is in the starting state and the ending state, the support force provided is zero; when the distance between the shield machine cutter head 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 shield machine cutter head 21 and the cross section of the trolley 4 is at the peak state, the support force provided is the peak support force F f When the distance between the shield machine cutter head 21 and the cross section where the trolley 4 is located is other distances, the support force is calculated by linear difference.

[0037] 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 clearance between the leading tunnel 1 and the trailing tunnel 3 to the outer diameter of the shield tunnel is the relative clearance. The support force provided by the jack is different for different relative burial depths and relative clearances. The support force increases with the increase of the relative burial depth and decreases with the increase of the relative clearance. When the relative clearance is the same, the value of the support force is a linear function of the relative burial depth.

[0038] Based on the field test, the test data were obtained through a large number of three-dimensional numerical simulations and centrifugal model tests after verification. Taking the case where the relative burial depth is h / D = 1 and the relative clearance is d / D = 0.1 and 0.2 respectively as an example, the change law of the jack support axial force with the position of the shield machine cutter head 21 determined by three-dimensional numerical simulation is as follows Figure 3 and Figure 4 As shown, the vertical support has the largest axial force, with peak values ​​of 105kN and 77kN respectively; the diagonal support has the second largest axial force, with peak values ​​of about 62kN and 44kN respectively; the horizontal support has the smallest axial force, with peak values ​​of only 9kN and 6kN respectively. The support axial force represents the axial force that the jack needs to apply. Considering the greater influence of the vertical jack on the control effect, the axial force is slightly larger, and the other values ​​are slightly rounded to get the recommended values ​​shown in Table 1.

[0039] In Table 1, the supporting forces provided by the jacks at different positions in the same group are different. The supporting force provided by the jack in the vertical direction is F 1 , the support force provided by the horizontal jack is F 2, the supporting force provided by the inclined jack is F 3 , F 1 >F 3 >F 2 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. When the relative burial depth is the same, the initial support force provided by the vertical jack is F c1 , the initial support force provided by the horizontal jack is F c2 , the initial support force provided by the inclined jack is F c3 ; When the relative clearance is 0.1, F c1 : F c3 : F c2 =5:3:1; when the relative clearance is 0.2, F c1 : F c3 : F c2 =3:2:0; when the relative clearance is 0.3, F c1 : F c3 : F c2 =2:1:0.

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

[0041]

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

[0043] The outer diameter of the shield tunnel is 6.2m, the width of each ring segment is 1.2m, and the top of the tunnel is buried at a depth of l 1 The horizontal clearance between the up and down tunnels is l 2 The diameter of the shield machine is 6.44m, and the length of the shield machine is l 3 is 8.86m, and the thrust F generated by the shield machine cutterhead t It is stable between 0.134 and 0.209 MPa, which is about 1.2 times the static lateral earth pressure. z , stable between 0.25 and 0.32 MPa, about 1.5 times the groundwater pressure. The shield machine construction parameters are within the normal range.

[0044] The trolley 4 sets a support cross section in each ring of the leading tunnel 1 segment. The maximum support force allowed by each hydraulic jack is 120kN, and the control accuracy is 5kN. The hydraulic jack applies support force to the ring segment of the leading tunnel 1 to share the thrust F generated by the cutter head of the shield machine during the construction of the subsequent tunnel 3. t and shield tail grouting pressure F z Additional pressure applied to the leading tunnel 1.

[0045] During the tunneling process of the shield machine 2, for each set of supporting jacks on the trolley 4, the supporting force of the jacks is set and dynamically adjusted according to the distance between the shield machine cutterhead 21 and the cross section where the supporting jacks are located. 3 , in order to facilitate on-site construction management, the initial state l 4 The shield machine cutterhead reaches the 8th ring segment before the cross section, the peak state l 5 The shield machine cutter head reaches the cross section after 8 ring segments, the end state l 6 It is the 15th ring segment after the shield machine cutterhead reaches the cross section. According to the relative burial depth of 1.85 and the relative clearance of 0.29, the relative burial depth of 2.0 and the relative clearance of 0.3 in Table 1 are taken approximately, and the initial support force of the vertical, oblique and horizontal jacks is taken as 20kN, 10kN and 0kN respectively, and the maximum support force of the vertical, oblique and horizontal jacks is taken as 80kN, 40kN and 10kN respectively.

[0046] Take a set of supporting jacks installed on the trolley 4 of the 620th ring of the leading tunnel 1 as an example. Since both tunnels have curves, the tunnel lengths vary due to different curve radii. At this time, the 620th ring of the leading tunnel 1 and the 634th ring of the following tunnel 3 are in the same cross section. Therefore, when the following tunnel 3 excavates the 626th ring, which is 8 rings before the 634th ring, the supporting jacks of the trolley 4 of the 620th ring of the leading tunnel 1 are ready to start applying supporting force. When the following shield tunnel excavates the 634th ring, the supporting forces of the vertical, oblique and horizontal jacks on the trolley 4 of the 620th ring of the leading tunnel 1 reach 20kN, 10kN and 0kN respectively; when the following shield tunnel excavates the 642nd ring, which is 8 rings after the 634th ring, the supporting forces of the vertical, oblique and horizontal jacks on the trolley 4 of the 620th ring of the leading tunnel 1 reach 80kN, 40kN and 10kN respectively. When the subsequent shield tunnel was excavated to the 649th ring, 15 rings after the 634th ring, the supporting force of the jack on the trolley 4 of the 620th ring of the leading tunnel 1 was completely removed.

[0047] When the rear shield tunnel continues to excavate the 650th ring and beyond, the trolley 4 of the 620th ring of the leading tunnel 1 can be removed. The trolley 4 can be disassembled and reassembled in the front, or the trolley 4 can be moved forward synchronously with the shield machine 2 to achieve the purpose of saving the engineering work of the trolley 4. When the distance l supported by the trolley 4 of the leading tunnel 1 is in the initial state l 4 To the end state 6 When within the range, the supporting force of the hydraulic jack must always meet the specified dynamic support parameter requirements, and the supporting force provided by the jack cannot be temporarily reduced due to the movement of the trolley 4.

[0048] The above construction conditions were monitored. During the construction of the rear tunnel 3, the convergence deformation of the 620th ring of the leading tunnel 1 increased by 9.3mm, and the relative convergence deformation was 9.3 / 6200=1.5‰, which met the control requirements of the design and construction technical guidelines for rail transit horizontal small clearance tunnels, that is, "the relative convergence deformation of the cross section of the leading shield tunnel still under construction due to the construction of small clearance shield tunnels shall not exceed ±0.6%" and "the support force of the jack of the trolley 4 shall not exceed the design value". The leading shield tunnel did not have problems such as joint leakage and segment cracking, ensuring the quality and safety of the ultra-small horizontal clearance shield tunnel project.

[0049] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A layout structure of a shield tunnel trolley, characterized in that: A plurality of groups of jacks are arranged at different positions on the outer surface of the trolley (4), a cross section of the position where the trolley (4) is provided with a group of jacks is cut, and a portion 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 a jack arrangement area, and within the jack arrangement area, a position of the trolley (4) closest to the tunnel top is taken as a starting point, and a jack is arranged at fixed angles from the starting point.

2. The arrangement structure of a shield tunnel trolley according to claim 1, characterized in that: The fixing angle is 45°, and a jack is set in the vertical direction to support the top of the tunnel; two jacks are set in the horizontal direction to support the arch waists on both sides of the tunnel respectively; Four oblique jacks are arranged to respectively support the arch shoulders and arch feet on both sides of the tunnel; a group of multiple jacks are distributed in a cross-section of the trolley (4) in a cross-section in the shape of a cross.

3. A dynamic support method using the arrangement structure of the shield tunnel trolley according to claim 2, characterized in that: The shield tunnel comprises a leading tunnel (1) and a trailing tunnel (3) having the same outer diameter, wherein the clearance between the leading tunnel (1) and the trailing tunnel (3) is less than 0.3 times the outer diameter of the shield tunnel; a trolley (4) is provided in the leading tunnel (1), and multiple groups of jacks of the trolley (4) provide support force for multiple positions of the leading tunnel (1); a shield machine (2) is located at one end of the trailing tunnel (3), and a shield machine cutterhead (21) is provided on the shield machine (2); the length of the shield machine is a first length; and the dynamic support method comprises: The initial state is defined as the shield machine cutterhead (21) arriving at the cross section where a set of jacks of the trolley (4) are located; the start state is the shield machine cutterhead (21) retreating a first length from the initial state; the peak state is the shield machine cutterhead (21) advancing a first length from the initial state; and the end state is the shield machine cutterhead (21) advancing twice the first length from the initial state; During the jack support process, when the shield machine cutterhead (21) is in the starting state and the ending state, the support force provided is zero; when the shield machine cutterhead (21) is in the initial state, the support force provided is the initial support force; when the shield machine cutterhead (21) is in the peak state, the support force provided is the peak support force; When the shield machine cutterhead (21) is located at other positions, the support force is calculated using a linear difference method.

4. A dynamic support method according to claim 3, characterized in that: The same group of jacks set at different positions provide different supporting forces. The supporting force provided by the vertical jack is F1, the supporting force provided by the horizontal jack is F2, and the supporting force provided by the oblique jack is F3, F1>F3>F2.

5. A dynamic support method according to claim 4, characterized in that: 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.

6. A dynamic support method according to claim 4, characterized in that: 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 clear distance between the preceding tunnel (1) and the following tunnel (3) to the outer diameter of the shield tunnel is the relative clear distance; different relative burial depths and relative clear distances provide different supporting forces for the jacks.

7. A dynamic support method according to claim 6, characterized in that: The supporting force increases with the increase of relative burial depth; the supporting force decreases with the increase of relative clear distance.

8. A dynamic support method according to claim 6, characterized in that: When the relative clearance is the same, the value of the supporting force is a linear function of the relative burial depth.

9. A dynamic support method according to claim 6, characterized in that: When the relative burial depth is the same, the initial support force provided by the jack in the vertical direction is F c1 , the initial support force provided by the horizontal jack is F c2 , the initial support force provided by the inclined jack is F c3 ; When the relative clearance is 0.1, F c1 : F c3 : F c2 =5:3:1; when the relative clearance is 0.2, F c1 : F c3 : F c2 =3:2:0; when the relative clearance is 0.3, F c1 : F c3 : F c2 =2:1:

0.

10. A dynamic support method according to claim 3, characterized in that: The maximum supporting force provided by the jack is 120kN, and the control accuracy is 5kN.

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