Multi-arch tunnel real-time adjustment active support system and control method thereof

Abstract

The application relates to the technical field of tunnel construction, and particularly discloses a multi-arch tunnel real-time adjusting active support system and a control method thereof. The multi-arch tunnel real-time adjusting active support system comprises a plurality of groups of active support gantries, the plurality of groups of active support gantries are arranged at equal intervals in a pilot hole of a tunnel, the active support gantries are adjustable, can support the lining inside, and form a pre-applied load; when a subsequent hole is excavated, the active support gantries are adjusted in real time, the vertical pressure of part of surrounding rock is balanced, and the stress on the inner surface of a partition wall is always located within a safe range. Compared with the current method of strengthening the lining of the pilot hole, the multi-arch tunnel real-time adjusting active support system can solve the problem of asymmetric surrounding rock pressure before the subsequent hole forms a bearing capacity without strengthening the lining of the pilot hole, avoid diseases such as cracking and crushing of the lining, and make the tunnel structure safely transit from the construction process working condition to the operation working condition, thereby greatly reducing the engineering investment.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a real-time adjustable active support system for a continuous arch tunnel and its control method. Background Technology

[0002] Twin-arch tunnels have gained favor among tunnel builders due to their excellent visual appeal, favorable alignment, smaller footprint, and numerous other advantages. However, traditional twin-arch tunnels with a central partition wall suffer from complex construction procedures, high economic and time costs, frequent disturbance to the surrounding rock, and difficulties in waterproofing and drainage of the central partition wall. In recent years, tunnel construction technology has matured, and the no-central-pivot tunnel method, which eliminates the central guide tunnel, constructs twin-arch tunnels as two independent tunnels sequentially. This effectively shortens the construction period, simplifies procedures, reduces disturbance to the surrounding rock, and solves problems such as the difficulty in waterproofing and drainage of the central partition wall.

[0003] For tunnels without a mid-level connecting arch, the construction difficulty lies in the following: the subsequent tunnel has been excavated, but before its lining can effectively bear the load, the lining structure is incomplete, the surrounding rock pressure is asymmetrical, the sidewalls of the intermediate tunnel lose their restraint, and the intermediate tunnel walls have large axial forces and bending moments, making them prone to cracking, crushing, and other defects. Currently, the solution to this problem is usually to strengthen the lining of the intermediate tunnel to ensure its structural safety; however, strengthening the lining of the intermediate tunnel results in excessive lining strength, affecting the symmetrical load-bearing of the complete lining structure, and significantly increasing the project investment. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a real-time adjustable active support system for a series of arch tunnels and its control method. This real-time adjustable active support system can resolve the problem of asymmetrical surrounding rock pressure before the subsequent tunnel reaches bearing capacity without reinforcing the lining of the preceding tunnel. It avoids cracking and crushing of the lining, allowing the tunnel structure to safely transition from construction conditions to operational conditions, and significantly reducing project investment.

[0005] The technical solution adopted in this invention is as follows:

[0006] A real-time adjustable active support system for a series-arch tunnel includes several sets of active support gantry frames. These gantry frames are evenly spaced within the tunnel's initial tunnel section and parallel to the excavation position of the subsequent tunnel section. Each active support gantry frame includes an upper structure and a lower structure. The upper and lower structures are connected via a jacking power source. The lower structure is placed on the ground within the initial tunnel section. The upper structure, through the jacking power source, can support the lining within the initial tunnel section, thereby altering the load applied to the lining.

[0007] Furthermore, the real-time adjustment active support system for the arch tunnel also includes a real-time monitoring and adjustment device. The real-time monitoring and adjustment device consists of several sensors and an information processor. Several sensors are deployed in the invert arch, central partition wall, arch shoulder and arch waist inside the tunnel. Several sensors are all connected to the information processor, and the information processor is connected to the lifting power source of each group of active support gantry for control.

[0008] Furthermore, the lower structure of the gantry is composed of four vertical steel pipes connected by several horizontal, longitudinal and diagonal I-beams to form a gantry-shaped support structure. The top of the four vertical steel pipes is provided with a connecting steel plate connected to the lifting power source, and the bottom of the four vertical steel pipes is provided with a lower steel plate in contact with the ground.

[0009] Furthermore, the upper structure of the gantry is composed of two parallel vertical steel pipes connected by two parallel horizontal H-beams. The bottom of the vertical steel pipe is provided with a connecting steel plate that is connected to the lifting power source, and the top of the vertical steel pipe is provided with an arc-shaped steel plate that can fit with the lining inside the pilot tunnel. The two sets of upper structures of the gantry are installed on a set of lower structures of the gantry.

[0010] Furthermore, the two parallel transverse I-beams of the upper structure of the gantry are connected by several vertical I-beams.

[0011] Furthermore, the lifting power source is a hydraulic jack.

[0012] A control method for a real-time adjustable active support system for a twin-arch tunnel, the method comprising the following steps:

[0013] Step 1: Several sets of active support gantry frames are deployed on both sides of the tunnel direction, centered on the excavation point of the subsequent tunnel, in the pilot tunnel; at the same time, several sensors that are connected to the information processor are deployed at the invert arch, central partition wall, arch shoulder and arch waist in the pilot tunnel.

[0014] Step 2 involves controlling each lifting power source of several groups of actively supporting gantry frames via an information processor. This causes the upper structure of the gantry frame to rise relative to the lower structure, supporting the lining inside the pilot tunnel and creating a pre-applied load. Sensors collect concrete surface strain data to determine the surface stress of the pilot tunnel lining concrete. By adjusting the load of the active support system, the surface stress of the pilot tunnel lining concrete is controlled between 0 and 0.5f. c Within this range, according to the Kent-Park constitutive model, the concrete stress is between 0 and 0.5f. c Within the specified range, there is no plastic deformation;

[0015] Step 3: Begin excavation of the subsequent tunnel. Simultaneously, monitor the surface stress of the lining concrete of the preceding tunnel in real time during construction. If the surface stress of the lining concrete exceeds 0.5f... c The information processor controls each lifting power source of several groups of actively supported gantry frames, increasing the load applied by the upper structure of each gantry frame to the lining of the tunnel under construction. By adjusting the load of the active support system, the surface stress of the concrete lining of the tunnel under construction is controlled in real time between 0 and 0.5f. c Within the range;

[0016] Step 4: After each construction cycle of the subsequent tunnel is completed, determine whether the tunnel face is located between the central axes of the cross sections of the two sets of active support gantry frames in the middle position. If it exceeds this, move each set of active support gantry frames one by one along the excavation direction of the subsequent tunnel to ensure that the tunnel face is always located between the central axes of the cross sections of the two sets of active support gantry frames in the middle position.

[0017] Furthermore, in steps 2 and 3, the information processor first obtains the surface strain ε of the lining concrete based on the data collected by the sensors. c The surface strain ε of the lining concrete c Substituting into the Kent-Park constitutive model, the surface stress δ of the lining concrete is calculated using the following formula. c ;

[0018] The calculation formula is: δ c =E c ε c

[0019] In the formula, E c Let be the elastic modulus of the lining concrete, which is a known quantity;

[0020] Secondly, it is important to check whether the surface stress value of the lining concrete is within the range of 0 to 0.5f. c Verification was conducted within the specified scope.

[0021] Furthermore, in step 4, when moving each group of active support gantry one by one, it is necessary to ensure that, except for the active support gantry being moved, all other groups of active support gantry are in normal working condition.

[0022] The beneficial effects of this invention are:

[0023] This real-time adjustable active support system for the arch tunnel uses several sets of active support portals to actively apply support loads to the preceding tunnel, balancing part of the vertical pressure on the surrounding rock. Simultaneously, it monitors the stress state of the preceding tunnel in real time through a real-time monitoring and adjustment device, adjusting the support loads applied to the preceding tunnel by the active support portals to ensure that the stress on the inner surface of the partition wall in the arch tunnel remains between 0 and 0.5f. cThis allows for the resolution of the asymmetric rock pressure issue before the subsequent tunnel reaches its bearing capacity without strengthening the lining of the preceding tunnel. It also prevents lining defects such as cracking and crushing, enabling the tunnel structure to safely transition from construction conditions to operational conditions and significantly reducing project investment. Attached Figure Description

[0024] Figure 1 A schematic diagram illustrating the use of a real-time adjustable active support system for a series of arch tunnels;

[0025] Figure 2 A schematic diagram of the overall structure of the actively supported gantry;

[0026] Figure 3 A schematic diagram of the lower structure of the gantry for active support;

[0027] Figure 4 A schematic diagram of the upper structure of the gantry for active support;

[0028] Figure 5 Schematic diagram of the installation location of the real-time monitoring and control device;

[0029] Figure 6 This is a flowchart of a construction method for a continuous arch tunnel based on a real-time adjustable active support system.

[0030] Figure 7 The stress-strain curves for the Kent-Park constitutive model are shown.

[0031] Figure 8 This is a diagram showing the location determination after each construction cycle of the tunnel is completed.

[0032] Figure 1 —In the diagram, 1—active support gantry, 2—preliminary opening, 3—rear opening, 4—upper structure of the gantry, 5—lower structure of the gantry, 6—lifting power source, 7—first vertical steel pipe, 8—transverse, longitudinal and diagonal H-beams, 9—first connecting steel plate, 10—lower steel plate, 11—second vertical steel pipe, 12—transverse H-beam, 13—second connecting steel plate, 14—arc-shaped steel plate, 15—vertical H-beam. 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] To address the current approach of reinforcing the lining of the pilot tunnel to solve the problem of asymmetrical surrounding rock pressure before the formation of bearing capacity in the subsequent tunnel during the construction of a continuous arch tunnel, and the issue that excessive lining strength and a significant increase in project investment occur when the partition wall in the pilot tunnel loses its restraint, this embodiment provides a control method for real-time adjustment of the active support system in a continuous arch tunnel. This construction method for a continuous arch tunnel is based on the real-time adjustment of the active support system in a continuous arch tunnel.

[0035] Specifically, taking the construction of a certain arch tunnel as an example, such as... Figure 1 As shown, the real-time adjustable active support system for the arch tunnel includes four sets of active support gantry frames 1. These four sets of active support gantry frames 1 are equally spaced within the tunnel's lead tunnel 2 and are parallel to the excavation position of the follow tunnel 3. For example... Figure 2 As shown, each active support gantry 1 includes an upper gantry structure 4 and a lower gantry structure 5. The upper gantry structure 4 and the lower gantry structure 5 are connected by a lifting power source 6. In this embodiment, the lifting power source 6 is a hydraulic jack. The lower gantry structure 5 is placed on the ground inside the pilot tunnel 2. The upper gantry structure 4 can support the lining inside the pilot tunnel by adjusting the hydraulic jack, giving the support gantry initiative and adjustability, and actively applying vertical support load to the arch of the pilot tunnel 2.

[0036] like Figure 3 As shown, the lower structure 5 of the gantry is a portal frame structure formed by welding four first vertical steel pipes 7 together with several transverse, longitudinal, and diagonal I-beams 8. A first connecting steel plate 9, connected to the lifting power source 6, is welded to the top of the four first vertical steel pipes 7, and a lower steel plate 10, in contact with the ground, is welded to the bottom of the four first vertical steel pipes 7. Figure 4 As shown, the upper structure 4 of the gantry is constructed by welding two parallel second vertical steel pipes 11 together with two parallel horizontal H-beams 12. A second connecting steel plate 13, connected to the lifting power source 6, is welded to the bottom of the second vertical steel pipes 11, and an arc-shaped steel plate 14, capable of fitting against the lining inside the pilot hole 2, is welded to the top of the second vertical steel pipes 11. To ensure the structural strength of the upper structure 4 of the gantry, five vertical H-beams 15 are welded between the two parallel horizontal H-beams 12. Figure 3 and Figure 4 As shown, two upper gantry structures 4 can be installed above a set of lower gantry structures 5 via four sets of lifting power sources 6. The lifting and lowering of the upper gantry structure 4 controlled by the two sets of lifting power sources 6 supports the lining inside the pilot tunnel 2 and actively applies support loads to the arch of the pilot tunnel 2.

[0037] Furthermore, in order to monitor the stress state of the lining of the pilot tunnel 2 in real time after the real-time adjustment active support system of the arch tunnel applies vertical support loads to the pilot tunnel 2, and to ensure that the stress magnitude at the control points of the pilot tunnel 2 is within a safe range, the real-time adjustment active support system of the arch tunnel also includes a real-time monitoring and adjustment device. This device consists of sensors and an information processor. There are four groups of sensors, three in each group, and the sensors are strain gauge sensors. Figure 5 As shown, four sets of sensors are respectively deployed at point A of the invert arch, point B of the central partition wall, point C of the arch shoulder, and point D of the arch waist inside the pilot tunnel 2. All twelve sensors in the four sets are connected to the information processor and are responsible for collecting concrete surface strain information data at point A of the invert arch, point B of the central partition wall, point C of the arch shoulder, and point D of the arch waist inside the pilot tunnel 2. The information processor is connected to the lifting power source 6 of each active support gantry 1 and is a processing computer. It adjusts the lifting power source 6 of each active support gantry 1 according to the concrete surface strain information, thereby ensuring that the active support system applies appropriate support load to the pilot tunnel 2 and that the stress on the surface of the lining concrete at the control points is within a safe range.

[0038] Based on the aforementioned real-time adjustable active support system for arch tunnels, according to... Figure 6 The steps shown illustrate support control during the construction of a twin-arch tunnel:

[0039] Step 1: Four sets of active support gantry frames 1 are installed at equal intervals in the pilot tunnel 2 of the continuous arch tunnel. The four sets of active support gantry frames 1 are installed on both sides of the tunnel direction with the excavation point of the subsequent tunnel 3 as the center. At the same time, four sets of twelve sensors that are connected to the information processor are installed at the invert arch, central partition wall, arch shoulder and arch waist in the pilot tunnel 2. The sensors are located between the second set of active support gantry frames 1 and the third set of active support gantry frames 1.

[0040] Step 2 involves controlling each of the four active support gantry 1 lifting power sources 6 via an information processor, raising the upper structure 4 of the gantry to support the lining inside the pilot tunnel 2, thus pre-applying a load. Simultaneously, sensors collect concrete surface strain data, and the information processor calculates the surface stress of the lining concrete, controlling the surface stress level of the lining concrete within the range of 0–0.5f. c Within this range; under this stress state, the concrete is in a fully elastic working state and does not produce plastic deformation, preventing defects in the lining.

[0041] Specifically, the information processor first obtains the surface strain ε of the lining concrete based on the data collected by the sensors. c Then, the surface strain ε of the lining concrete is measured. c Substituting into the Kent-Park constitutive model, such as Figure 7As shown in the figure, the horizontal axis represents the concrete strain, and the vertical axis represents the lining concrete stress; the surface strain ε of the lining concrete is known. c Substituting into the constitutive model, the surface stress δ of the lining concrete can be obtained. c ;

[0042] The calculation formula is: δ c =E c ε c

[0043] In the formula, E c ε is the elastic modulus of the lining concrete, and ε is a known numerical value of the material properties of the lining concrete. c The maximum strain value of the lining concrete surface is taken from the twelve sensors.

[0044] Secondly, the information processor is based on the calculated surface stress δ of the lining concrete. c Determine whether it is within the range of 0 to 0.5f. c Within safe limits.

[0045] If the surface stress value of the lining concrete is between 0 and 0.5f c Within this range, there is no need to adjust the load applied by the four sets of active support gantry 1. If the surface stress value of the lining concrete is not between 0 and 0.5f c Within the specified range, the load applied by the four sets of active support gantry frames 1 is adjusted to control the surface stress of the lining concrete of the pilot tunnel within the range of 0–0.5f. c Within the range.

[0046] Step 3: Begin excavation of the subsequent tunnel 3, while simultaneously monitoring the lining stress in real time during construction. Taking the partition wall monitoring point in the preliminary tunnel 2 as an example, if the lining stress exceeds 0.5f... c The information processor then controls each lifting power source 6 of the four active support gantry frames 1, increasing the load applied to the lining of the pilot tunnel 2 by the upper structure 4 of each gantry frame. Similarly, in step 2, during the construction of the subsequent tunnel 3, the stress on the surface of the lining concrete of the pilot tunnel is controlled in real time between 0 and 0.5f by adjusting the load of the active support system. c Within the range.

[0047] Step 4: After each construction cycle of the subsequent tunnel 3, determine whether the working face of the subsequent tunnel 3 is located between the second set of active support gantry frames 1 and the third set of active support gantry frames 1; if so... Figure 8 As shown, if the position of the working face of the rear tunnel 3 exceeds... Figure 8Within the range between a and b, each group of active support gantry 1 is moved one by one along the excavation direction of the subsequent tunnel 3; at the same time, the placement of the sensors is adjusted. When moving each group of active support gantry 1 one by one, it is necessary to ensure that all active support gantry 1 except the one being moved are in normal working condition, and it is not allowed to remove the preload at the same time for two or more gantry 1s. (Operations such as relocation are also not permitted.)

[0048] In summary, the construction method for this twin-arch tunnel, based on the pre-application of loads in step 2 and the real-time adjustment of support loads according to the surface stress monitoring data of the lining concrete of the pilot tunnel 2 during construction in step 3, can prevent lining defects. By actively applying loads to the arch crown of the pilot tunnel 2 lining, part of the vertical surrounding rock pressure is balanced, allowing the pilot tunnel 2 to safely transition from construction to operational conditions without reinforcing its lining. This significantly reduces material costs and improves the project's economic efficiency. By real-time monitoring of the surface stress of the lining concrete of the pilot tunnel 2 and correspondingly adjusting the loads applied by each set of active support gantry 1, the lining stress is controlled to remain between 0 and 0.5f. c Within this range, the concrete is in a fully elastic working state under this stress state, without plastic deformation, thus preventing defects in the lining.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A control method for a real-time adjustable active support system for a continuous arch tunnel, the method being based on a real-time adjustable active support system for a continuous arch tunnel, characterized in that: The real-time adjustable active support system for the twin-arch tunnel includes several sets of active support gantry frames, which are equally spaced within the tunnel's initial tunnel and parallel to the excavation position of the subsequent tunnel. Each active support gantry frame consists of an upper structure and a lower structure, connected by a jacking power source. The lower structure rests on the ground within the initial tunnel, while the upper structure, via the jacking power source, supports the lining within the initial tunnel, altering the load applied to the lining. The system also includes a real-time monitoring and adjustment device, composed of several sensors and an information processor. These sensors are deployed at the invert, central partition, arch shoulders, and arch waist within the initial tunnel, and are communicatively connected to the information processor. The information processor is connected to the lifting power source of each group of active support gantry frames. The lower structure of the gantry frame consists of four vertical steel pipes connected by several horizontal, longitudinal, and diagonal H-beams to form a gantry-shaped support structure. The top of the four vertical steel pipes is equipped with a connecting steel plate connected to the lifting power source, and the bottom of the four vertical steel pipes is equipped with a lower steel plate in contact with the ground. The upper structure of the gantry frame consists of two parallel vertical steel pipes connected by two parallel horizontal H-beams. The bottom of the vertical steel pipes is equipped with a connecting steel plate connected to the lifting power source, and the top of the vertical steel pipes is equipped with an arc-shaped steel plate that can fit against the lining inside the tunnel. The two groups of upper gantry frame structures are installed on one group of lower gantry frame structures. The two parallel horizontal H-beams of the upper gantry frame structure are connected by several vertical H-beams. The lifting power source is a hydraulic jack. The upper structure of the gantry can support the lining inside the tunnel through a jacking power source, giving the supporting gantry initiative and adjustability, and actively applying vertical support loads to the arch of the tunnel. The aforementioned active supporting gantry consists of four sets of active supporting gantry, which are equally spaced inside the tunnel's initial tunnel and parallel to the excavation position of the subsequent tunnel. The sensors consist of four sets, with three sensors in each set, and the sensors are strain gauge sensors. Four sets of sensors are respectively deployed at the invert arch, central partition wall, arch shoulder, and arch waist inside the pilot tunnel. All twelve sensors in the four sets are connected to the information processor and are responsible for collecting concrete surface strain information data at the invert arch, central partition wall, arch shoulder, and arch waist inside the pilot tunnel. The information processor is connected to the jacking power source of each set of active support gantry frames. The information processor is a processing computer that adjusts the jacking power source of each set of active support gantry frames according to the concrete surface strain information, thereby ensuring that the active support system applies appropriate support load to the pilot tunnel and that the stress on the surface of the lining concrete at the control points is within a safe range. The control method includes the following steps: Step 1: Several sets of active support gantry frames are deployed on both sides of the tunnel direction, centered on the excavation point of the subsequent tunnel, in the pilot tunnel; at the same time, several sensors that are connected to the information processor are deployed at the invert arch, central partition wall, arch shoulder and arch waist in the pilot tunnel. Step 2 involves controlling each lifting power source of several groups of actively supporting gantry frames via an information processor. This causes the upper structure of the gantry frame to rise relative to the lower structure, supporting the lining inside the pilot tunnel and creating a pre-applied load. Sensors collect concrete surface strain data to determine the surface stress of the pilot tunnel lining concrete. By adjusting the load of the active support system, the surface stress of the pilot tunnel lining concrete is controlled between 0 and 0.

5. Within the range; In step 2, the information processor first obtains the surface strain of the lining concrete based on the data collected by the sensors, and then substitutes the surface strain of the lining concrete into the Kent-Park constitutive model to calculate the surface stress of the lining concrete. The calculation formula is: ； In the formula, Let be the elastic modulus of the lining concrete, which is a known quantity; The maximum strain value on the surface of the lining concrete was selected from the twelve sensors. Secondly, the information processor is based on the calculated surface stress of the lining concrete. Determine whether it falls within the range of 0 to 0.

5. Within a safe range; if the surface stress value of the lining concrete is between 0 and 0.

5. Within this range, there is no need to adjust the load applied by the four sets of active support gantry frames. If the surface stress value of the lining concrete is not between 0 and 0.5... Within this range, the load applied by the four sets of active support gantry frames is adjusted to control the surface stress of the lining concrete of the pilot tunnel within the range of 0–0.

5. Within the range; Step 3: Begin excavation of the subsequent tunnel. Simultaneously, monitor the surface stress of the lining concrete of the preceding tunnel in real time during construction. If the surface stress of the lining concrete exceeds 0.5... The information processor controls each lifting power source of several groups of actively supported gantry frames, increasing the load applied by the upper structure of each gantry frame to the lining of the tunnel under construction. By adjusting the load of the active support system, the surface stress of the concrete lining of the tunnel under construction is controlled in real time between 0 and 0.

5. Within the range; In step 3, the information processor first obtains the surface strain of the lining concrete based on the data collected by the sensors, and then substitutes the surface strain of the lining concrete into the Kent-Park constitutive model to calculate the surface stress of the lining concrete. The calculation formula is: In the formula, Let be the elastic modulus of the lining concrete, which is a known quantity; The maximum strain value on the surface of the lining concrete was selected from the twelve sensors. Secondly, based on the known surface stress of the lining concrete, the value of the surface stress of the lining concrete is verified to be within the range of 0 to 0.5fc. Step 4: After each construction cycle of the subsequent tunnel is completed, determine whether the tunnel face is located between the cross-sectional center axes of the two sets of active support gantry frames in the middle position. If it exceeds this, move each set of active support gantry frames one by one along the excavation direction of the subsequent tunnel to ensure that the tunnel face is always located between the cross-sectional center axes of the two sets of active support gantry frames in the middle position. In step 4, while moving each group of active support gantry frames one by one along the direction of the tunnel excavation, the placement of the sensors should be adjusted at the same time. In step 4, when moving each group of active support gantry frames one by one, it is necessary to ensure that all active support gantry frames except the one being moved are in normal working condition. It is not allowed for two or more gantry frames to be removed from pre-stressing or moved at the same time.

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