A support trolley for an overlapping shield tunnel, a pipe section correction method and a supporting method thereof

Abstract

The application discloses a kind of superimposed shield tunnel support trolley and pipe section correction method, supporting method thereof, belong to tunnel engineering technical field, support trolley includes trolley body, trolley body circumferentially is equipped with several pairs of retractable support feet, measuring device for measuring pipe section diameter size is equipped on trolley body.Pipe section correction method includes S1, measures pipe section initial hole diameter Dn;S2, the changing hole diameter Dn of monitoring support foot corresponding pipe section t ;S3, according to convergence value ΔDn is corrected.Supporting method includes S1, preset initial pipe section supporting quantity in downlink tunnel and lay out support trolley;S2, shield travels to the support trolley pipe section end above when pause excavation in end, all support trolley moves a pipe section;S4, when shield pause excavation again, all support trolley moves a pipe section again;S5, repeat step S4 step, until uplink tunnel completes excavation.Effective support can be carried out to downlink tunnel, and deformation pipe section can be corrected.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering technology, and in particular to a composite shield tunnel support trolley and its pipe section correction method and support method. Background Technology

[0002] With the increasing number of underground facilities, it is inevitable that new shield tunnels will be constructed close to operational tunnels. Due to limitations imposed by surrounding environmental factors, in some sections, the spatial position of the two tunnels will be changed from horizontal parallel to vertical overlapping, i.e., composite shield tunnels. From domestic and international engineering practice, there are relatively few examples of long-distance, small-clearance composite tunnel projects; most are short-distance, small-angle overlapping tunnels. After the downstream shield tunnel is constructed first, the construction of the upstream shield tunnel will inevitably disturb and deform the already constructed downstream shield tunnel. To reduce the mutual impact of the composite tunnel construction, it is necessary to provide support within the downstream tunnel to minimize the construction impact. Currently, for projects involving overlapping tunnels, the support system within the existing tunnel mainly uses a steel support system. This system utilizes steel supports mounted on the tunnel segments to bear external loads and reduce segment deformation. However, the installation and transportation of steel support systems within the tunnel are difficult, and it is impossible to correct the convergence point of the tunnel segments when deformation occurs, resulting in a low level of automation.

[0003] To address this, patent number "201510074563.X" and patent title "A Supporting Trolley and Supporting Trolley System for Overlapping Shield Tunnel Construction" discloses a supporting trolley and supporting trolley system. The supporting trolley includes a frame body with wheels at the bottom. Multiple supporting cylinders are arranged radially along the tunnel circumference of the frame body. Each supporting cylinder has a bracket at its end, and a rubber pad is provided on the end face of the bracket. A pump station for driving the supporting cylinders is also provided on the frame body. By setting up several sets of supporting trolleys in the descending tunnel, the tunnel sections of the descending tunnel can be supported, reducing disturbance to the descending tunnel when the shield excavates the ascending tunnel. As the shield advances, the supporting trolleys can be moved sequentially, starting with the first one, to adapt to the progress of the shield excavation. Compared to traditional steel support systems, the aforementioned support trolley system offers significant improvements in ease of installation and transportation. However, it still cannot correct for the deformation convergence of the tunnel segments. Furthermore, the support trolley movement in this method involves moving the trolley from the beginning at intervals, then sequentially, and finally moving it from the end. This approach is not only cumbersome and unreasonable, but also requires complex calculations for the travel intervals, resulting in a complicated construction method that is not easily promoted. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems and provide a composite shield tunnel support trolley and its pipe section correction method and support method. It can not only effectively support the pipe sections of the down-going tunnel and reduce the interference brought about by the construction of the up-going tunnel, but also correct the pipe sections that have undergone convergent deformation, bear the additional stress brought about by the construction of the up-going tunnel, and ensure the safety of the down-going tunnel in real time and effectively, and reduce the problem of pipe section deformation.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention discloses a composite shield tunnel support trolley, including a trolley body capable of traveling along the tunnel track. The trolley body is evenly provided with several pairs of retractable support legs in the circumference. Two of the support legs in each pair are symmetrically arranged along the radial direction of the tunnel section. The trolley body is provided with a measuring device for measuring the diameter of the tunnel section corresponding to each pair of support legs.

[0006] Preferably, the trolley body includes a trolley bracket, the bottom of the trolley bracket is provided with a track wheel with a built-in wheel lock, the top of the trolley bracket is fixed with a core shaft, the core shaft is fitted with a bearing shaft, the bearing shaft and the core shaft are rotatably connected by a bearing, the core shaft is provided with a brake for braking the bearing shaft, and the support feet are circumferentially arranged on the outer wall of the bearing shaft.

[0007] Preferably, the brake is an electro-hydraulic brake, and a hydraulic servo controller is provided inside the core shaft cylinder. The electro-hydraulic brake is connected to the hydraulic servo controller through an oil pressure pipe.

[0008] Preferably, the support foot is a servo hydraulic jack, the telescopic end of the servo hydraulic jack is provided with an arc-shaped foot support, the fixed end of the servo hydraulic jack is fixedly connected to the outer wall of the bearing shaft cylinder, and the servo hydraulic jack is connected to the hydraulic servo controller through an oil pressure pipe.

[0009] Preferably, the measuring device includes a distance measuring device circumferentially arranged on the outer wall of the bearing shaft cylinder, and the distance measuring device corresponds to the number and arrangement position of the support legs.

[0010] Preferably, the ranging device is a laser displacement sensor or an ultrasonic ranging device.

[0011] A method for correcting composite shield tunnel segments is also disclosed, which uses the aforementioned composite shield tunnel support trolley and includes the following steps:

[0012] S1. Number the several pairs of support legs in sequence, measure the diameter of the pipe section corresponding to each pair of support legs using the measuring device, and record it as the initial hole diameter Dn, where n represents a pair of numbers;

[0013] S2. The diameter of the pipe section corresponding to each pair of support legs is monitored in real time by the measuring device and recorded as the variable tunnel diameter Dn. t t represents a certain moment;

[0014] S3. Using the formula ΔDn=Dn-Dn t The convergence value ΔDn of the pipe section corresponding to each pair of support legs is obtained at a certain moment. When the convergence value ΔDn of the pipe section corresponding to a pair of support legs is >0, the pair of support legs grow synchronously and the common growth amount is ΔDn. When the ΔDn of a pair of support legs is <0, the pair of support legs does not need to be extended.

[0015] A method for supporting composite shield tunnels is also disclosed, including the following steps:

[0016] S1. Along the direction of the shield tunneling machine's travel in the upward tunnel, the initial number of pipe sections to be supported is preset in the overlapping section of the downward tunnel, and a support trolley is set up on the track below each pipe section for support.

[0017] S2. Start the shield machine to excavate the upward tunnel. When it reaches the top of the end of the support trolley, stop the excavation. Starting from the end support trolley, move all the support trolleys together one section in the direction of the shield machine's movement.

[0018] S4. Start the tunnel boring machine to continue excavation until it reaches above the end of the support trolley. Stop excavation and start moving all the support trolleys one segment in the direction of the tunnel boring machine's movement again, starting from the end support trolley.

[0019] S5. Repeat steps S4 until the overlapping section between the up tunnel and the down tunnel is completely excavated.

[0020] Preferably, the number of initial pipe sections for support is determined based on the disturbance range generated during the shield excavation process.

[0021] Preferably, the support trolley is the aforementioned composite shield tunnel support trolley, and during the shield excavation process, each of the composite shield tunnel support trolleys promptly corrects the tunnel sections.

[0022] The present invention achieves the following technical effects compared to the prior art:

[0023] 1. Compared with the prior art, the support trolley of this invention can detect the convergence value of the pipe sections of the completed down-running tunnel through a measuring device, and transmit pressure to the pipe sections through the support legs. It can not only effectively support the pipe sections of the down-running tunnel, but also adjust the pressure in real time according to the changes in the convergence value, so as to correct the convergent deformation of the pipe sections, ensure the safety of the down-running tunnel in a real time and effectively, and reduce the pipe section deformation problem caused by disturbances during the construction of the up-running tunnel.

[0024] 2. The support trolley in this invention can apply constant pressure and adjust in real time. By rotating the bearing cylinder, the hydraulic jack can apply a constant load to any position in the circumferential direction of the tunnel. Furthermore, the convergence value of the tunnel can be obtained in real time through the ranging device arranged on the trolley, and the load value applied to the inner wall of the pipe section can be dynamically adjusted to balance the additional pressure on the pipe section caused by the construction of the upward tunnel in the downward tunnel. This ensures that the cross-sectional shape of the downward tunnel does not exceed the limit in real time and that the pipe section structure is safe and stable.

[0025] 3. The pipe section correction method in this invention compares the initial diameter of the down-going tunnel pipe section with the real-time changes in the diameter of the down-going tunnel pipe section during the shield excavation process, adjusts the applied load based on the feedback convergence value, and applies corresponding loading to the pipe section at the convergence change point to correct the pipe section convergence change point. It has a high degree of intelligence.

[0026] 4. In the support method of this invention, the support trolley in the downhill tunnel provides continuous and uninterrupted support in rings according to the tunnel boring machine's progress in the uphill tunnel. This allows the support of the downhill tunnel to be carried out synchronously with the construction of the uphill tunnel, greatly ensuring the stability of the downhill tunnel segments. At the same time, the method of moving the support trolley from end to end in rings is more reasonable than the existing method of moving it sequentially from end to end according to spacing. The method of moving it sequentially from end to end according to segment is simpler, requires no calculation of the moving spacing, and is easier to promote. The above-mentioned moving method has better synchronization. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A side view of the structure supporting the trolley;

[0029] Figure 2 for Figure 1A front view structural schematic diagram of the AA' section supporting the trolley;

[0030] Figure 3 A simplified diagram illustrating the support legs for the trolley;

[0031] Figure 4 This is a schematic diagram of the support method.

[0032] Explanation of reference numerals in the attached drawings: 1. Pipe section; 2. Track; 3. Trolley support; 4. Track wheel; 5. Wheel locker; 6. Core shaft cylinder; 7. Bearing; 8. Bearing shaft cylinder; 9. Flange A; 10. Flange B; 11. Flange bolt; 12. Servo hydraulic jack; 13. Connecting rod base; 14. Arc-shaped foot support; 15. Steel connecting rod; 16. Distance measuring device; 17. Target point; 18. Displacement data acquisition box; 19. Hydraulic servo controller; 20. Hydraulic pipe; 21. Electro-hydraulic brake. Detailed Implementation

[0033] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a composite shield tunnel support trolley, such as Figures 1 to 4 As shown, the device includes a trolley body capable of traveling along track 2 within the tunnel. The trolley body has several pairs of retractable support legs evenly distributed circumferentially. Two support legs in each pair are symmetrically arranged radially along the tunnel section 1. The trolley body is equipped with a measuring device for measuring the diameter of the section 1 corresponding to each pair of support legs. There are at least two pairs of support legs. (Refer to...) Figure 2 It is a support trolley for a composite shield tunnel with four pairs of support legs, that is, a total of eight support legs.

[0036] Working principle

[0037] ① Support process: After the trolley body moves along the track 2 of the down tunnel to the overlapping section that overlaps with the up tunnel, the support legs extend and abut against the pipe section 1 of the down tunnel, thus supporting the overlapping section of the down tunnel. This reduces the disturbance to the down tunnel and the deformation of the pipe section 1 of the down tunnel when the shield tunneling machine is excavating the overlapping section of the up tunnel.

[0038] ② Correction Process: The diameter of the pipe section 1 supported by each pair of support legs can be pre-measured using a measuring device. Then, the diameter of the pipe section 1 supported by each pair of support legs is monitored in real time during the tunnel boring process. The pre-measured diameter is compared with the diameter measured at a later time to obtain the change. If the later measured diameter decreases, the elongation of each pair of support legs is increased. The sum of the elongations equals the change, thus correcting the pipe section 1. If the later measured diameter increases, no correction is needed. It is important to note that the elongations of the two support legs in each pair must be consistent.

[0039] In this embodiment, as Figures 1 to 4 As shown, the trolley body includes a trolley support 3, with track wheels 4 at the bottom of the trolley support 3, each track wheel having a built-in wheel locker 5. A core shaft cylinder 6 is fixed to the top of the trolley support 3, which can be connected by welding or bolting. To ensure sufficient support strength and rigidity, the core shaft cylinder 6 has a wall thickness ≥50mm. A load-bearing shaft cylinder 8 is fitted around the core shaft cylinder 6, and the load-bearing shaft cylinder 8 and the core shaft cylinder 6 are rotatably connected by a bearing 7, which can be a ball bearing. A brake 21 is provided on the core shaft cylinder 6 to brake the load-bearing shaft cylinder 8, and support feet are circumferentially arranged on the outer wall of the load-bearing shaft cylinder 8. By manually rotating the load-bearing shaft cylinder 8, the position of the tube section 1 corresponding to the support feet on the load-bearing shaft cylinder 8 can be changed, and the load-bearing shaft cylinder 8 can be locked by the brake 21.

[0040] Furthermore, in this embodiment, as Figures 1 to 4 As shown, brake 21 is an electro-hydraulic brake. A hydraulic servo controller 19 is installed inside the core shaft cylinder 6. The electro-hydraulic brake is connected to the hydraulic servo controller 19 via an oil pressure pipe 20. The hydraulic servo controller 19 can be connected to the core shaft cylinder 6 by bolts and provides oil pressure to the electro-hydraulic brake through the oil pressure pipe 20. The electro-hydraulic brake can be welded or bolted to the outside of the core shaft cylinder 6.

[0041] In this embodiment, as Figures 1 to 4 As shown, the support foot is a servo hydraulic jack 12. The telescopic end of the servo hydraulic jack 12 is provided with an arc-shaped foot support 14. The arc of the arc-shaped foot support 14 is adapted to the arc of the pipe section 1. The arc-shaped foot support 14 and the telescopic end of the servo hydraulic jack 12 can be fixed by welding. The fixed end of the servo hydraulic jack 12 is fixed to the outer wall of the bearing shaft cylinder 8. The servo hydraulic jack 12 is connected to the hydraulic servo controller 19 through the hydraulic pipe 20. The hydraulic servo controller 19 can provide hydraulic pressure to the servo hydraulic jack 12 through the hydraulic pipe 20. Preferably, a rubber pad can also be provided on the end face of the arc-shaped foot support 14 to avoid damage to the pipe section 1.

[0042] Furthermore, in this embodiment, as Figures 1 to 4As shown, the fixed end of the servo hydraulic jack 12 is connected to the flange of the bearing shaft cylinder 8. Specifically, a flange A9 is pre-installed on the outer wall of the bearing shaft cylinder 8 and fixed with flange bolts 11. Then, a flange B10 is installed at the fixed end of the servo hydraulic jack 12 and fixed with flange bolts 11. Finally, flanges A9 and B10 are fixed with ordinary bolts.

[0043] To improve the connection stability between the servo hydraulic jacks 12, in this embodiment, as follows: Figures 1 to 4 As shown, the fixed ends of adjacent servo hydraulic jacks 12 are connected by steel connecting rods 15. Specifically, connecting rod bases 13 are pre-welded to the fixed end of each servo hydraulic jack 12, and the two ends of the steel connecting rods 15 are respectively installed on the connecting rod bases 13 of the two adjacent servo hydraulic jacks 12.

[0044] In this embodiment, as Figures 1 to 4 As shown, the measuring device includes distance measuring devices 16 circumferentially arranged on the outer wall of the bearing shaft cylinder 8. The number and arrangement of the distance measuring devices 16 correspond to the number and position of the support feet (servo hydraulic jacks 12). The distances between the two opposing distance measuring devices and the pipe section 1 are measured, and added to the diameter of the bearing shaft cylinder 8 to obtain the diameter of the pipe section 1 at this time. A displacement data acquisition box 18 is provided on the inner wall of the core shaft cylinder 6, and the displacement data acquisition box 18 is electrically connected to the distance measuring devices 16. The distance measuring devices 16 transmit displacement data to the displacement data acquisition box 18, which is fixed to the core shaft cylinder 6 by bolts.

[0045] Furthermore, in this embodiment, as Figures 1 to 4 As shown, the ranging device 16 is either a laser displacement sensor or an ultrasonic ranging device. Considering cost and accuracy, a laser displacement sensor is preferred. Furthermore, to improve testing accuracy, target points 17 can be pre-laid on the pipe section 1. The target points 17 are made of 100mm×100mm acrylic plates and can be fixed to the pipe section 1 by adhesive bonding.

[0046] Example 2

[0047] This embodiment provides a method for correcting composite shield tunnel segments, employing a composite shield tunnel support trolley as shown in Embodiment 1. Figures 1 to 4 As shown, it includes the following steps:

[0048] S1. Number several pairs of support legs in sequence, measure the diameter of pipe section 1 corresponding to each pair of support legs using a measuring device, and record it as the initial tunnel diameter Dn, where n represents a pair of numbers;

[0049] S2. Monitor the diameter of pipe section 1 corresponding to each pair of support legs in real time using a measuring device, and record it as the variable tunnel diameter Dn. t t represents a certain moment;

[0050] S3. Using the formula ΔDn=Dn-Dn t The convergence value ΔDn of pipe section 1 corresponding to each pair of support legs is obtained at a certain moment. When the convergence value ΔDn of pipe section 1 corresponding to a pair of support legs is >0, the pair of support legs grow synchronously and the common growth amount is ΔDn. When ΔDn of a pair of support legs is <0, the pair of support legs do not need to be extended.

[0051] Work process:

[0052] Taking a composite shield tunnel support trolley with four pairs (eight) of support legs as an example (refer to...) Figure 2 and Figure 3 ):

[0053] The four pairs of support legs of the composite shield tunnel support trolley are numbered sequentially as 1, 2, 3, and 4. The initial tunnel diameters (diameters) at pipe segment 1 corresponding to the four pairs of support legs are denoted as D1, D2, D3, and D4. The composite shield tunnel support trolley begins to apply loads to pipe segment 1, and the convergence value of pipe segment 1 is collected in real time through the measuring device on the trolley. At this time, the changed tunnel diameters (diameters) at pipe segment 1 corresponding to the four pairs of support legs are denoted as D1. t D2 t D3 t D4 t The formula ΔDn=Dn-Dn t The convergence values ​​of the composite shield tunnel support trolley are obtained as ΔD1, ΔD2, ΔD3, and ΔD4. The calculation process is as follows:

[0054] ΔD1=D1-D1 t ;

[0055] ΔD2=D2-D2 t ;

[0056] ΔD3=D2-D2 t ;

[0057] ΔD4=D2-D2 t .

[0058] The loading strategy is as follows: when the convergence value is positive (ΔDn > 0), the load is increased in the direction, with each pair of support legs increasing by ΔDn. When the convergence value is negative (ΔDn < 0), no load is added in this direction. Specifically, if ΔD1 > 0, the pair of support legs numbered 1 is extended, with a total increase of ΔD1 for both support legs. It is important to note that the increase in the two support legs is the same.

[0059] Example 3

[0060] This embodiment provides a method for supporting composite shield tunnels, such as... Figures 1 to 4 As shown, it includes the following steps:

[0061] S1. Along the direction of the shield tunneling machine's travel in the upward tunnel, the initial number of pipe sections to be supported is preset in the overlapping section of the downward tunnel, and support trolleys are set up on the track 2 below each pipe section 1 for support. The number of support trolleys below each pipe section 1 is set according to the actual construction support requirements. Preferably, one support trolley is set below each pipe section 1.

[0062] S2. Start the shield tunneling to excavate the upward tunnel. When it reaches above the end of the support trolley 1, the excavation is paused. Starting from the end support trolley, all support trolleys are moved as a whole in the direction of shield tunneling movement by one section 1.

[0063] S4. Start the tunnel boring machine to continue excavation until it reaches the top of the end of the support trolley 1. Stop the excavation and start moving all the support trolleys one section 1 in the direction of the tunnel boring machine's movement again.

[0064] S5. Repeat steps S4 until the overlapping section between the up tunnel and the down tunnel is completely excavated.

[0065] The support trolley mentioned above can be a support trolley in the prior art, or it can be the composite shield tunnel support trolley in Embodiment 1. However, the existing support trolley does not have a correction function. Therefore, if a correction function is required, the composite shield tunnel support trolley in Embodiment 1 is needed.

[0066] Work process:

[0067] Taking a 100m overlap between the upstream and downstream tunnels as an example, the number of support trolleys can be selected from 8 to 12. Here, we take 8 trolleys as an example. The total support length is eight pipe sections 1. Typically, the length of pipe section 1 is 1.2m. Therefore, the total support length can be considered as 8 x 1.2 = 9.6m. (For reference) Figure 4 :

[0068] ① The 8 support trolleys are numbered sequentially as 1, 2, 3...8.

[0069] ② For the upward tunnel, the shield tunneling machine advances from the lower mileage direction to the higher mileage direction. For the downward tunnel, the support trolleys can be pre-entered into the tunnel from the end shaft in the higher mileage direction, and then pre-arranged one by one from the higher mileage direction to the lower mileage direction. They are positioned at the predetermined support locations, and then the support legs are extended to support and pressurize the pipe section 1. That is, support trolley No. 1 moves first to the overlapping section, moving to below the first pipe section 1 at the beginning of the overlapping section, which is the first pipe section 1 of the preset initial pipe section. Then support trolleys No. 2 to No. 8 enter in sequence, corresponding to the second to eighth pipe sections 1.

[0070] ③ The shield tunneling machine in the upward tunnel begins excavation. When the upward tunnel reaches the end of the eighth ring segment 1, the excavation is suspended. The support legs of the No. 8 support trolley retract to relieve pressure. The No. 8 support trolley moves one ring segment 1 in the direction of the greater mileage. Then the support legs of the No. 8 support trolley extend to apply the specified load to the segment 1 again. Subsequently, the No. 7 support trolley is depressurized and moves forward one ring and begins to pressurize. This process is repeated until the No. 1 support trolley completes the loading.

[0071] ④ Start the shield tunneling to continue excavation. For each ring that the shield tunneling machine advances in the upward tunnel, repeat the operation in step ③ to complete the depressurization-reloading cycle.

[0072] In this embodiment, as Figures 1 to 4 As shown, the initial number of pipe sections to be supported is determined based on the disturbance range generated during the shield tunneling excavation process. For example, if the shield tunneling disturbance is about 9m, then 8 pipe sections can be supported (8 x 1.2m = 9.6m). If the shield tunneling disturbance is about 12m, then 10 pipe sections can be supported (10 x 1.2m = 12m). And so on.

[0073] Furthermore, in this embodiment, as Figures 1 to 4 As shown, the support trolley adopts a composite shield tunnel support trolley as described in Example 1. During the shield excavation process, each composite shield tunnel support trolley should promptly correct the deformation of the pipe section 1. The correction method can be the method described in Example 2.

[0074] Work process:

[0075] Taking the aforementioned overlapping section as 100m and selecting 8 support trolleys as an example, each support trolley has 4 pairs of support legs:

[0076] Before the 8 support trolleys support the pipe section 1 in step ②, a measuring device is used to measure the diameter of the pipe section 1 corresponding to the 4 pairs of support legs on each of the support trolleys 1 to 8, so as to obtain the initial tunnel diameters R1 to R4.

[0077] In step ③, during the tunnel boring machine's movement, the measuring devices on support trolleys 1 to 8 must monitor the changes in tunnel diameter R1 of each of the four pairs of support legs in real time. t ~R4 t (t represents a certain moment), and then according to the formula ΔDn=Dn-Dn t The convergence values ​​of the composite shield tunnel support trolley are obtained as ΔD1, ΔD2, ΔD3, and ΔD4, and corrections are made based on the positive or negative value of ΔD1. As the upward shield tunnel advances, the corresponding trolley in the downward tunnel begins to be loaded, ensuring that the synchronous support of the downward tunnel is carried out in sync with the construction of the upward tunnel.

[0078] In step ④, as the shield tunnel advances one ring, the operation in step ③ is repeated to complete the cycle of depressurization-reloading-monitoring-real-time load adjustment.

[0079] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for supporting composite shield tunnels, characterized in that, Includes the following steps: S1. Along the direction of the shield tunneling machine's travel in the upward tunnel, the initial number of pipe sections to be supported is preset in the overlapping section of the downward tunnel, and a support trolley is set up on the track below each pipe section for support. S2. Start the shield machine to excavate the upward tunnel. When it reaches the top of the end of the support trolley, stop the excavation. Starting from the end support trolley, move all the support trolleys together one section in the direction of the shield machine's movement. S4. Start the tunnel boring machine to continue excavation until it reaches above the end of the support trolley. Stop excavation and start moving all the support trolleys one segment in the direction of the tunnel boring machine's movement again, starting from the end support trolley. S5. Repeat the steps in S4 until the overlapping section between the up tunnel and the down tunnel is completely excavated. The supporting trolley is a composite shield tunnel supporting trolley, which includes a trolley body capable of moving along the tunnel track. The trolley body has several pairs of retractable supporting legs evenly distributed circumferentially. Two of the supporting legs in each pair are symmetrically arranged radially along the tunnel segment. The trolley body is equipped with a measuring device for measuring the diameter of the segment corresponding to each pair of supporting legs. The trolley body includes a trolley bracket, with track wheels with built-in wheel locks at the bottom. A core shaft is fixed to the top of the trolley bracket, and a bearing shaft is fitted around the core shaft. The bearing shaft and the core shaft are rotatably connected by bearings. The core shaft is equipped with a brake for braking the bearing shaft. The supporting legs are circumferentially arranged on the outer wall of the bearing shaft. The measuring device includes a distance measuring device circumferentially arranged on the outer wall of the bearing shaft, corresponding to the number and arrangement of the supporting legs. During the shield excavation process, the composite shield tunnel support trolleys promptly correct the tunnel sections. The method for correcting composite shield tunnel sections includes the following steps: Step 1: Number the several pairs of support legs in sequence, measure the diameter of the pipe section corresponding to each pair of support legs using the measuring device, and record it as the initial hole diameter Dn, where n represents a pair of numbers; Step 2: Monitor the diameter of the pipe section corresponding to each pair of support legs in real time using the measuring device, and record it as the variable tunnel diameter Dn. t t represents a certain moment; Step 3: Using the formula ΔDn=Dn-Dn t The convergence value ΔDn of the pipe section corresponding to each pair of support legs is obtained at a certain moment. When the convergence value ΔDn of the pipe section corresponding to a pair of support legs is >0, the pair of support legs grow synchronously and the common growth amount is ΔDn. When the ΔDn of a pair of support legs is <0, the pair of support legs does not need to be extended.

2. The composite shield tunnel support method according to claim 1, characterized in that, The brake is an electro-hydraulic brake, and a hydraulic servo controller is installed inside the core shaft. The electro-hydraulic brake is connected to the hydraulic servo controller through an oil pressure pipe.

3. The composite shield tunnel support method according to claim 2, characterized in that, The support foot is a servo hydraulic jack. The telescopic end of the servo hydraulic jack is provided with an arc-shaped foot support. The fixed end of the servo hydraulic jack is fixedly connected to the outer wall of the bearing shaft cylinder. The servo hydraulic jack is connected to the hydraulic servo controller through an oil pressure pipe.

4. The composite shield tunnel support method according to claim 1, characterized in that, The ranging device is a laser displacement sensor or an ultrasonic ranging device.

5. The composite shield tunnel support method according to claim 1, characterized in that, The initial number of pipe sections for support is determined based on the disturbance range generated during the shield excavation process.

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