A tunnel steel arch support structure and its secondary yield control method

Abstract

The present invention discloses a tunnel steel arch support structure and a secondary pressure relief control method thereof. By connecting an outer arch ring, an inner arch ring, joint one and joint two in cooperation, two closed-loop steel arches are formed to adapt to the arched-section tunnel set under a relatively large external pressure. Among them, joint one connects the outer segment of the outer arch ring and the inner segment of the inner arch ring at the same time, and joint two only connects the outer segment. Joint one can contract circumferentially and radially along the tunnel, and joint two can contract circumferentially along the tunnel. When the steel arch is subjected to a relatively large surrounding rock pressure, first, joint one contracts radially, and at the same time, joint two contracts circumferentially to realize the pressure relief contraction of the outer arch ring, which is the first pressure relief; when the outer arch ring fits the inner arch ring, the first pressure relief ends. If the steel arch is further subjected to a greater surrounding rock pressure, joint one and joint two contract circumferentially at the same time to realize the common pressure relief contraction of the outer arch ring and the inner arch ring, which is the secondary pressure relief.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel support, and particularly to a tunnel steel arch support structure and a yielding control method thereof. Background Art

[0002] During the tunnel construction process, it is inevitable to face problems such as high surrounding rock stress and large deformation. However, the existing strong support measures cannot meet the requirements of surrounding rock deformation control, and are prone to yield failure of the support structure, affecting construction safety. In response to this situation, the principle of "yielding support" has been proposed, which means maintaining a certain support resistance, allowing the support body to generate a certain displacement while maintaining the stability of the supported body, so as to achieve the effects of support and unloading.

[0003] In the literature "Dong Jianhua, He Pengfei, Qin Zhaoxian. Proposal and analysis of the anti-pulling bearing capacity characteristics of shape memory alloy bolts [J]. China Civil Engineering Journal, 2023.", a bolt made of shape memory alloy is mentioned. It can have a fixed shape in the martensite phase and austenite phase, and can induce phase transformation by changing the temperature of the alloy sheet, so that the shape of the alloy sheet returns, and then rapid forming can be achieved. In the patent application for invention "A tunnel steel arch support structure and a yielding control method thereof" with the publication number CN118462253A, a yielding support structure including the above-mentioned memory alloy is recorded. The support structure includes a plurality of alternately arranged segments and joints, which are slidably connected along the length direction of the segments; the joint includes a memory alloy damping block whose volume shrinks when heated and expands when cooled, and the memory alloy damping block is attached to the segment and changes the friction force between the two by volume change. Therefore, the support structure realizes the yielding support effect of "resisting while yielding", ensuring that the tunnel steel arch support structure has a support force while having the ability to bear deformation.

[0004] However, this structure also has disadvantages. Its yielding function comes from the deformation of the shape memory alloy damping block, which causes relative sliding between the segment and the shape memory alloy damping block, thereby causing the tunnel steel arch to shrink inward and releasing the internal force of the arch. During the yielding process, due to the pressure, the deformation of the shape memory alloy damping block cannot be restored and yield again. Therefore, its yielding function can only occur once, that is, one-time yielding. So its yielding function is limited and is only suitable for the case where the surrounding rock pressure is not very large. However, during the tunnel excavation process, due to the different tunnel depths and soil structures, the surrounding rock pressure of the tunnel cross-section will also be different. Therefore, in the case of large surrounding rock pressure, the yielding ability of the above-mentioned yielding support structure is insufficient and cannot provide sufficient support force, which will also lead to structural yield failure and affect construction safety. And currently, for different strengths of surrounding rock pressure, different tunnel cross-sections will be selected during construction. Among them, the design of the arched cross-section can well support the heavy pressure above and on both sides, and its bearing capacity is also better. Therefore, in order to fit the arched cross-section with stronger bearing capacity, a joint structure with a larger yielding amount is also required to cooperate with it. Therefore, based on the above problems, a support structure and a yielding control method that can yield twice and are more suitable for the arched cross-section are needed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a tunnel support steel arch and its secondary yielding control method.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A tunnel steel arch support structure includes an outer arch ring abutting against the inner wall of the surrounding rock and an inner arch ring arranged at intervals inside the outer arch ring; the outer arch ring includes a plurality of outer segments arranged at intervals and a plurality of joints two arranged at intervals and connected to the outer segments; the inner arch ring includes a plurality of inner segments arranged at intervals; adjacent inner segments are connected by a joint one to form a closed ring structure, and the joint one is also connected to the outer segment at the same time, so that each outer segment is connected to the joint two through the joint one to form a closed ring structure; the joint one can contract respectively along the circumferential and radial directions of the tunnel, thereby respectively reducing the circumferences of the outer arch ring and the inner arch ring, and reducing the distance between the outer arch ring and the inner arch ring.

[0008] As a further improvement of the above technical solution:

[0009] The cross-section of the inner segment is U-shaped. The first joint includes a first retraction device that is embedded and installed in this cross-section and contracts along the circumferential direction of the tunnel. The first retraction device includes a plate damper whose damping effect varies with temperature, a sliding plate, and several connecting sliders. The plate damper is installed between the sliding plate and the inner segment. The two ends of the sliding plate are provided with sliding holes distributed along its length direction. The connecting sliders, the plate damper, and the inner segment are fixed by bolts and are slidably connected to the sliding plate through the sliding holes.

[0010] The connecting slider is slidably connected to the top surface of the sliding plate and between the plate damper and the inner segment through the sliding hole.

[0011] The first joint further includes a second retraction device that contracts along the radial direction of the tunnel. The second retraction device includes a spring damper whose damping effect varies with temperature. The upper end of the spring damper abuts against the bottom of the outer segment, and the lower end abuts against the sliding plate.

[0012] The second retraction device further includes a support column vertically penetrating and installed in the middle of the sliding plate, and the spring damper is arranged around the support column.

[0013] The plate damper, the spring damper, and the shape memory alloy damper in the second joint are all electrically connected to a damping control module for controlling their temperature changes.

[0014] Monitoring devices for monitoring the pressure borne by the support structure are provided on each of the outer segments and each of the inner segments.

[0015] One of the first joints is arranged at the crown and at the two wall shoulders of the support structure respectively, and one of the second joints is installed between two adjacent first joints.

[0016] A secondary yielding control method for a tunnel steel arch support structure as described above includes the following steps:

[0017] S1: Before the arch pressure is released, the first joint and the second joint are in a power-off state. At this time, their damping effects are the greatest. The connecting slider is located at both ends of the sliding plate, and the spring damper is in a diastolic state;

[0018] S2: Judge the magnitude of the force on the arch according to the monitoring device. When the force on the outer arch ring is greater than the set value, that is, when yielding is required, heat the spring damper and the shape memory alloy damper through the damping control module to cause the shape memory alloy to undergo a phase change, and the damping of the spring damper and the shape memory alloy damper is reduced. Therefore, the outer arch ring undergoes radial and circumferential retraction to release the pressure on the outer arch ring;

[0019] S3: When the force on the outer arch ring is less than the set value, control the damping control module to power off, cool down the spring damper and the shape memory alloy damper, and the spring damper and the shape memory alloy damper return to the state with the maximum damping, and the spring damper is in a compressed state;

[0020] S4: Repeat the steps of S2 - S3. When the outer arch ring fits the inner arch ring, the steel arch frame returns to a stable state, completing one pressure relief.

[0021] S5: When the steel arch frame is stressed again, at this time, both the outer arch ring and the inner arch ring are squeezed. When the monitoring device determines that the stress on the steel arch frame is greater than the set value, the plate damper and the shape memory alloy damper block are heated through the damping control module, causing the shape memory alloy to undergo a phase change, and the damping of the plate damper and the shape memory alloy damper block decreases. Therefore, the outer arch ring and the inner arch ring shrink circumferentially inward.

[0022] S6: When the stress on the steel arch frame is less than the set value, the damping control module is powered off to cool the plate damper and the shape memory alloy damper block, and the plate damper and the shape memory alloy damper block return to the state with the maximum damping.

[0023] S7: Repeat the steps of S5 - S6. The steel arch frame finally maintains a stable state, completing the secondary pressure relief.

[0024] As a further improvement of the above technical solution:

[0025] In S2 and S5: The heating temperature of the plate damper, the spring damper, and the shape memory alloy damper block is controlled between 50°C and 60°C.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] By setting two pressure reliefs, the steel arch frame can provide more pressure relief, thereby achieving a greater load-bearing capacity. Moreover, the closed-loop arched steel arch frame also fits better with the arched-section tunnel selected under the condition of greater surrounding rock pressure. At the same time, setting two pressure reliefs can better meet the load-bearing requirements and cost control requirements of greater surrounding rock pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic three-dimensional view of the structure of the tunnel steel arch frame in the embodiment;

[0029] Figure 2 is a schematic view of the structure of joint 1 in the embodiment (the damping control module is not shown);

[0030] Figure 3 is a schematic connection view of the plate damper and the damping control module in the embodiment;

[0031] Figure 4 is a schematic view of the structure of the sliding plate in the embodiment;

[0032] Figure 5 is a schematic connection view of the spring damper and the damping control module in the embodiment;

[0033] Figure 6 It is a schematic perspective view of the second joint in the embodiment;

[0034] Figure 7 It is a schematic connection diagram of the memory damping block and the damping control module in the embodiment.

[0035] Each label in the figure represents:

[0036] 1. Outer arch ring; 11. Outer segment; 2. Inner arch ring; 21. Inner segment; 3. First joint; 31. First retraction device; 311. Plate damper; 312. Slide plate; 3121. Slide hole; 313. Connecting slider; 314. Bolt; 32. Second retraction device; 321. Spring damper; 322. Support column; 4. Second joint; 41. Shape memory alloy damping block; 5. Damping control module; 6. Monitoring device. Specific embodiments

[0037] The present invention will be further described in detail below with reference to the accompanying drawings of the specification and specific embodiments.

[0038] Such as Figures 1 to 7As shown in the figure, the tunnel steel arch support structure of this embodiment includes an outer arch ring 1 abutting against the inner wall of the surrounding rock, and an inner arch ring 2 arranged at intervals inside the outer arch ring 1; the outer arch ring 1 includes a plurality of outer segments 11 arranged at intervals and a plurality of joints two 4 arranged at intervals and connected to the outer segments 11, and the inner arch ring 2 includes a plurality of inner segments 21 arranged at intervals; adjacent inner segments 21 are connected by a joint one 3 to form a closed ring structure, and the joint one 3 is also connected to the outer segment 11 at the same time, so that each outer segment 11 is connected to the joint two 4 through the joint one 3 to form a closed ring structure; the joint one 3 can contract along the circumferential and radial directions of the tunnel respectively, so as to reduce the circumferences of the outer arch ring 1 and the inner arch ring 2 respectively, and reduce the distance between the outer arch ring 1 and the inner arch ring 2. The present invention is a further research and development based on the invention patent application with the publication number of CN118462253A, "A Tunnel Steel Arch Support Structure and Its Yielding Control Method". The joint two 4 in this application is the joint disclosed in CN118462253A: The joint includes a shape memory alloy damping block whose volume shrinks when heated and increases when cooled, and the shape memory alloy damping block is attached to the steel arch segment and changes the friction force between the two through volume change; it also includes a joint body and a connecting slider; the joint body is provided with sliding grooves distributed along its length direction, and there are two groups of connecting sliders, which are slidably connected to both ends of the joint body in the length direction through the sliding grooves; a connecting groove for installing the joint is provided on the segment, and the connecting groove is fixedly connected to the connecting slider. The joint body includes a damping surface that fits the connecting groove, and the shape memory alloy damping block is arranged on the damping surface. Based on the reference document "Dong Jianhua, He Pengfei, Qin Zhaoxian. Proposal and Analysis of the Pull-out Bearing Capacity Characteristics of Shape Memory Alloy Anchors [J]. China Civil Engineering Journal, 2023.", the characteristics and structure changes of shape memory alloy with temperature are disclosed, which are specifically reflected as follows: The internal characteristics of shape memory alloy have the ability of recoverability. When its internal structure is in the martensite phase, it is in the best damping state. When it is heated to the start point of austenite phase transformation, the shape memory alloy starts to transform, and its damping effect decreases; after the internal structure of the shape memory alloy becomes austenite phase, it can be cooled to reach the start point of reverse martensite phase transformation, and the crystal phase inside the shape memory alloy changes, generating a recovery stress. Continuing to cool to the end point of reverse martensite phase transformation, the internal structure of the shape memory alloy completely returns to martensite, and the damping effect returns to the best state again.

[0039] In this embodiment, the outer arch ring 1, the inner arch ring 2, the first joint 3 and the second joint 4 are cooperatively connected to form two closed-loop steel arch frames to adapt to an arched section with stronger load-bearing capacity. Among them, the first joint 3 is simultaneously connected to the outer section 11 of the outer arch ring 1 and the inner section 21 of the inner arch ring 2, and the second joint 4 is only connected to the outer section 11. And the first joint 3 can contract in the circumferential and radial directions of the tunnel, and the second joint 4 can contract in the circumferential direction of the tunnel. Therefore, when the steel arch frame is subjected to surrounding rock pressure, first, the first joint 3 contracts radially while the second joint 4 contracts circumferentially to realize the yielding contraction of the outer arch ring 1, which is the first yielding; when the outer arch ring 1 fits against the inner arch ring 2, the first yielding ends. If the steel arch frame is further subjected to greater surrounding rock pressure, the first joint 3 contracts circumferentially, and at the same time, the second joint also contracts circumferentially to realize the common yielding contraction of the outer arch ring 1 and the inner arch ring 2, which is the second yielding. By setting two yieldings, the steel arch frame can provide more yielding amount, thereby obtaining greater load-bearing capacity, and the closed-loop steel arch frame is also more adaptable to the arched section with stronger load-bearing capacity, so it can be better applied to the scenario with greater surrounding rock pressure.

[0040] In this embodiment, the cross-section of the inner section 21 is U-shaped. The first joint 3 includes a first retraction device 31 that is embedded and installed in this cross-section and contracts in the circumferential direction of the tunnel. The first retraction device 31 includes a plate-type damper 311 whose damping effect changes with temperature, a sliding plate 312, and a plurality of connecting sliders 313. The plate-type damper 311 is installed between the sliding plate 312 and the inner section 21. Both ends of the sliding plate 312 are provided with sliding holes 3121 distributed along its length direction. The connecting sliders 313, the plate-type damper 311, and the inner section 21 are fixed by bolts 314 and are slidably connected to the sliding plate 312 through the sliding holes 3121. The first joint 3 is connected to the inner section 21 through the first retraction device 31. The plate-type damper 311 is made of shape memory alloy. Since the characteristics and structure of the shape memory alloy change with temperature, by increasing the temperature of the plate-type damper 311, its damping effect is reduced, the friction force between the first retraction device 31 and the inner section 21 is reduced, and the inner section 21 drives the connecting sliders 313 and the plate-type damper 311 to slide relative to the sliding plate 312 along the sliding holes 3121, so that the inner arch ring 2 contracts, releasing the internal force of the arch frame. After achieving the expected effect, the temperature of the plate-type damper 311 is reduced again to restore its damping effect, and finally, a static equilibrium state is reached. By controlling the damping effect of the plate-type damper 311 through temperature, the friction force and position between the inner section 21 and the first joint 3 are changed, thereby realizing controllable yielding contraction.

[0041] In this embodiment, the connecting sliders 313 are slidably connected to the top surface of the sliding plate 312 and between the plate-type damper 311 and the inner section 21 through the sliding holes 3121. The connecting sliders 313 include at least two pieces, which are respectively used to protect the plate-type damper 311 and the sliding plate 312 from damage and provide an installation basis for the sliding connection between the inner section 21 and the first retraction device 31.

[0042] In this embodiment, the first joint 3 further includes a second retraction device 32 that contracts along the radial direction of the tunnel. The second retraction device 32 includes a spring damper 321 whose damping effect changes with temperature. The upper end of the spring damper 321 abuts against the bottom of the outer segment 11, and the lower end abuts against the sliding plate 312. The second retraction device 32 further includes a support column 322 vertically penetrating and installed in the middle of the sliding plate 312, and the spring damper 321 is arranged around the support column 322. The spring damper 321 is also made of shape memory alloy. Therefore, by controlling the temperature change of the spring damper 321, its damping is regulated, and then the contraction in the radial direction of the tunnel is achieved, so that the distance between the outer arch ring 1 and the inner arch ring 2 is reduced. And in this process, the first-stage yielding and retraction is completed through the synchronous circumferential contraction of the second joint 4. The support column 322 vertically penetrating and installed in the middle of the sliding plate 312 is used to provide an installation foundation for the spring damper 321 to prevent it from undergoing lateral deformation, and a base is also installed at the bottom of the support column 322 to prevent the first joint 3 from falling off radially, thus ensuring that the second retraction device 32 smoothly realizes the contraction in the radial direction.

[0043] In this embodiment, the plate damper 311, the spring damper 321, and the shape memory alloy damper block 41 in the second joint 4 are all electrically connected to a damping control module 5 for controlling their temperature changes. Monitoring devices 6 for monitoring the pressure borne by the support structure are provided on each outer segment 11 and each inner segment 21. The surrounding rock pressure borne by the outer arch ring 1 and the inner arch ring 2 is monitored by the monitoring device 6, and the temperature changes of the plate damper 311, the spring damper 321, and the shape memory alloy damper block 41 are controlled by the damping control module 5, so as to regulate the change of the damping effect, and then the yielding amount can be correspondingly regulated according to the magnitude of the surrounding rock pressure during the yielding process, realizing precise yielding control.

[0044] In this embodiment, a joint 1-3 is arranged at the crown of the support structure and at the two shoulder positions of the side walls respectively, and a joint 2-4 is installed between two adjacent joints 1-3. According to the stress condition of the steel arch support structure, in this embodiment, a joint 1-3 is provided at the crown of the support structure, at the two shoulder positions of the side walls, at the two side wall positions and at the arch bottom respectively, and a joint 2-4 is installed between two adjacent joints 1-3, so that both the outer arch ring 1 and the inner arch ring 2 form a closed arch style to adapt to the arched cross-section tunnel; and the outer arch ring 1 itself has the ability to yield and resist the surrounding rock pressure; and by adding a plurality of joints 1-3 and joints 2-4, each joint can be individually adjusted according to the stress and yielding requirements. To ensure that the steel arch can successfully achieve yielding twice, it is necessary to ensure that the outer arch ring 1 can continue to deform with the inner arch ring 2 after completing radial contraction and fitting the inner arch ring 2. Therefore, a joint 2-4 is installed between two adjacent joints 1-3. After the radial contraction of the joint 1-3 is completed, the joint 2-4 has not reached the yielding limit and still retains the circumferential yielding amount. Therefore, when the inner retraction device 1-31 of the joint 1-3 and the inner segment 2-1 perform circumferential contraction of the inner arch ring 2 along the tunnel, the joint 2-4 can also follow to perform circumferential contraction of the outer arch ring 1 along the tunnel, thus ensuring the feasibility of the device.

[0045] The secondary yielding control method for the tunnel steel arch support structure as described above in this embodiment includes the following steps:

[0046] S1: Before the arch support pressure is released, the joint 1-3 and the joint 2-4 are in a power-off state. At this time, their damping effects are the greatest. The connecting slider 3-13 is located at both ends of the slide plate 3-12, and the spring damper 3-21 is in a diastolic state;

[0047] S2: According to the monitoring device 6, judge the magnitude of the arch support stress. The pressure borne by the outer arch ring 1 is between 1.5 and 2 Mpa. In this embodiment, the set value is selected as 1.5 Mpa. When the stress on the outer arch ring 1 is greater than the set value of 1.5 Mpa, yielding is required. The spring damper 3-21 and the shape memory alloy damping block 4-1 are heated through the damping control module 5 to cause the shape memory alloy to undergo a phase change, and the damping of the spring damper 3-21 and the shape memory alloy damping block 4-1 is reduced. Therefore, the outer arch ring 1 undergoes radial and circumferential inward contraction under the force of the surrounding rock pressure, releasing the pressure of the outer arch ring 1. In this process, the surrounding rock pressure corresponding to each millimeter of yielding amount needs to be measured on site. Assuming that the surrounding rock pressure corresponding to a deformation of 1 mm at the site is 1 Kpa, that is, whenever the surrounding rock pressure increases by 1 Kpa, each spring damper 3-21 of the outer arch ring 1 needs to contract by 1 mm, and the corresponding joints 2-4 at different positions contract by π / 2 mm and 1 mm respectively according to the arc length formula and geometric relationship.

[0048] S3: When the force on the outer arch ring 1 is less than the set value of 1.5 Mpa, there is no need for pressure relief and inward contraction at this time. Therefore, by controlling the damping control module 5 to cut off the power supply, the spring damper 321 and the shape memory alloy damper block 41 are cooled down. The spring damper 321 and the shape memory alloy damper block 41 return to the state with the maximum damping, and the spring damper 321 is in a compressed state;

[0049] S4: Repeat steps S2 - S3 to keep the surrounding rock pressure borne by the outer arch ring 1 at about 1.5 Mpa all the time. When the outer arch ring 1 fits the inner arch ring 2, the spring damper 321 reaches the maximum pressure relief amount, and the steel arch frame returns to a stable state, completing one pressure relief;

[0050] S5: When the steel arch frame is stressed again, at this time, both the outer arch ring 1 and the inner arch ring 2 are squeezed. At this time, the outer arch ring 1 and the inner arch ring 2 jointly resist the surrounding rock pressure. At this time, the surrounding rock pressure that can be borne is greater than the surrounding rock pressure borne by the outer arch ring 1 alone during the first - stage pressure relief. Therefore, when the monitoring device 6 determines that the force on the steel arch frame is greater than the set value of 1.8 Mpa, the damping control module 5 heats the plate damper 311 and the shape memory alloy damper block 41, causing the shape memory alloy to undergo a phase change, and the damping of the plate damper 311 and the shape memory alloy damper block 41 decreases. Therefore, the outer arch ring 1 and the inner arch ring 2 simultaneously contract circumferentially;

[0051] S6: When the force on the steel arch frame is less than the set value of 1.8 Mpa, by controlling the damping control module 5 to cut off the power supply, the plate damper 311 and the shape memory alloy damper block 41 are cooled down, and the plate damper 311 and the shape memory alloy damper block 41 return to the state with the maximum damping;

[0052] S7: Repeat steps S5 - S6, and the steel arch frame finally maintains a stable state, completing the second - stage pressure relief.

[0053] In this embodiment, in S2 and S5: The heating temperature of the plate damper 311, the spring damper 321, and the shape memory alloy damper block 41 is controlled between 50 °C and 60 °C.

[0054] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the above - disclosed technical content without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A tunnel steel arch support structure, characterized in that: The invention comprises an outer arch ring (1) abutting against the inner wall of the surrounding rock, and an inner arch ring (2) arranged at intervals inside the outer arch ring (1); the outer arch ring (1) comprises a plurality of outer segments (11) arranged at intervals and a plurality of second joints (4) arranged at intervals and connected to the outer segments (11); the inner arch ring (2) comprises a plurality of inner segments (21) arranged at intervals; adjacent inner segments (21) are connected via first joints (3) to form a closed annular structure, and the first joints (3) are simultaneously connected to the outer segments (11), so that each outer segment (11) is connected via the first joints (3) to the second joints (4) to form a closed annular structure; the first joints (3) can be contracted in the circumferential direction and radial direction of the tunnel respectively, thereby reducing the circumferences of the outer arch ring (1) and the inner arch ring (2), respectively, so as to reduce the circumferences of the outer arch ring (1) and the inner arch ring (2), respectively. and reducing the distance between the outer arch ring (1) and the inner arch ring (2); the cross section of the inner segment (21) is U-shaped, the joint (3) comprises an inner retracting device (31) embedded in the cross section and retracted along the circumferential direction of the tunnel, the inner retracting device (31) comprises a plate-type damper (311) whose damping effect changes with temperature, a slide plate (312) and a plurality of connecting slide blocks (313), the plate-type damper (311) is installed between the slide plate (312) and the inner segment (21), both ends of the slide plate (312) are provided with sliding holes (3121) distributed along the length direction thereof, the connecting slide block (313), the plate-type damper (311) and the inner segment (21) are fixed by bolts (314) and are slidably connected to the slide plate (312) through the sliding holes (3121).

2. The tunnel steel arch support structure according to claim 1 is characterized in that: The connecting sliding block (313) is slidably connected to the top surface of the sliding plate (312) and between the plate-type damper (311) and the inner segment (21) through the sliding hole (3121).

3. The tunnel steel arch support structure according to claim 1 is characterized in that: The joint 1 (3) further comprises a retracting device 2 (32) that contracts in the radial direction of the tunnel, the retracting device 2 (32) comprising a spring damper (321) whose damping effect varies with temperature, the upper end of the spring damper (321) abutting against the bottom of the outer segment (11), and the lower end abutting against the slide plate (312).

4. The tunnel steel arch support structure according to claim 3 is characterized in that: The second retracting device (32) further comprises a support column (322) vertically penetrating and installed in the middle of the slide plate (312), and the spring damper (321) is arranged around the support column (322).

5. The tunnel steel arch support structure according to claim 3 is characterized in that: The plate-type damper (311), the spring damper (321) and the memory alloy damping block (41) in the second joint (4) are all electrically connected to a damping control module (5) for controlling the temperature change thereof.

6. The tunnel steel arch support structure according to claim 5 is characterized in that: Each of the outer segments (11) and each of the inner segments (21) is provided with a monitoring device (6) for monitoring the pressure borne by the supporting structure.

7. The tunnel steel arch support structure according to claim 5, characterized in that: A joint 1 (3) is arranged at the arch and two wall shoulders of the supporting structure, and a joint 2 (4) is installed between two adjacent joints 1 (3).

8. A secondary pressure relief control method for the tunnel steel arch support structure according to claim 6 or 7, characterized in that: The following steps are involved: S1: before the arch pressure is released, the first joint (3) and the second joint (4) are in a power-off state, at which time the damping effect of the two is the greatest, the connecting slider (313) is located on the two ends of the slide plate (312), and the spring damper (321) is in a relaxed state; S2: judging the magnitude of the force on the arch frame according to the monitoring device (6), when the force on the outer arch ring (1) is greater than the set value, i.e. when pressure relief is required, heating the spring damper (321) and the memory alloy damping block (41) through the damping control module (5) causes the memory alloy to undergo a phase change, thereby reducing the damping of the spring damper (321) and the memory alloy damping block (41), thereby causing the outer arch ring (1) to retract radially and circumferentially, thereby releasing the pressure on the outer arch ring (1); S3: When the force applied to the outer arch ring (1) is less than a set value, the damping control module (5) is powered off to cool the spring damper (321) and the memory alloy damping block (41), so that the spring damper (321) and the memory alloy damping block (41) are restored to a maximum damping state, and the spring damper (321) is in a compressed state; S4: Repeat steps S2-S3, and when the outer arch ring (1) fits the inner arch ring (2), the steel arch frame returns to a stable state, completing one pressure release; S5: When the steel arch frame is subjected to stress again, the outer arch ring (1) and the inner arch ring (2) are squeezed at the same time. When the monitoring device (6) determines that the stress on the steel arch frame is greater than the set value, the damping control module (5) heats the plate damper (311) and the memory alloy damping block (41) to cause the memory alloy to undergo a phase change, and the damping of the plate damper (311) and the memory alloy damping block (41) is reduced, so that the outer arch ring (1) and the inner arch ring (2) are circumferentially retracted. S6: When the force on the steel arch frame is less than the set value, the damping control module (5) is powered off to cool the plate damper (311) and the memory alloy damping block (41), so that the plate damper (311) and the memory alloy damping block (41) are restored to a maximum damping state; S7: Repeat steps S5-S6, and the steel arch frame finally maintains a stable state, completing the second pressure relief.

9. The secondary pressure relief control method for a tunnel steel arch support structure according to claim 8, characterized in that: In S2 and S5: the heating temperature of the plate damper (311), the spring damper (321) and the memory alloy damping block (41) is controlled between 50° C. and 60° C.

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