A soft rock large deformation tunnel buffering and energy absorbing lining structure and a layered construction method thereof

Abstract

The application discloses a soft rock large deformation tunnel buffering energy-absorbing lining structure and a layered construction method thereof, which comprises a first lining layer and a second lining layer, the first lining layer comprises a first steel mesh and a soft filler layer, the second lining layer comprises a second steel mesh and a concrete filler layer, and an energy-absorbing assembly is arranged in the second lining layer, wherein the energy-absorbing assembly comprises a support, a first buffer, a second buffer and a fixing plate, one end of the support is in joint cooperation with the first steel mesh, and the other end of the support transmits stress to the first buffer and the second buffer to realize bidirectional energy absorption, the soft filler is adopted to eliminate the initial deformation stress of surrounding rock, meanwhile, the energy-absorbing assembly can realize bidirectional elastic energy absorption, and the soft rock tunnel multi-dimensional complex deformation pressure can be adapted in all directions, and the problem of stress accumulation and cracking of the traditional rigid lining is solved completely.

Description

Technical Field

[0001] This invention discloses a buffer energy-absorbing lining structure for large deformation tunnels in soft rock and its layered construction method, belonging to the field of tunnel lining support construction technology. Background Technology

[0002] With the continuous development of transportation infrastructure construction, tunnel projects are increasingly traversing soft rock strata with high ground stress. Soft rock is characterized by low strength, large deformation, and significant rheological properties. Under high ground stress, it is prone to large deformation, generating enormous compressive stress on the tunnel lining structure, which seriously threatens the safety and long-term stability of the tunnel structure.

[0003] Traditional tunnel linings mostly use a single rigid concrete lining structure, relying on the strength of the structure itself to resist the deformation pressure of the surrounding rock. However, rigid linings lack a buffer and pressure relief structure, making them unsuitable for the continuous rheological deformation of soft rock. The stress generated by the small deformation of the surrounding rock cannot be relieved, and long-term accumulation can easily lead to lining cracking, bulging, misalignment, or even overall collapse, resulting in extremely poor support durability and safety. At the same time, composite lining structures are mostly double-layer rigid supports, with unreasonable stiffness matching between the inner and outer lining layers and a lack of a step-by-step energy absorption and pressure relief mechanism. The stress of the surrounding rock directly impacts the high-strength inner lining, resulting in concentrated structural stress and a tendency for local stress overload damage. Moreover, because the energy absorption mode of tunnel energy-absorbing lining structures is singular, it can only relieve deformation stress in one direction, making it unsuitable for the complex multidimensional deformation pressure of soft rock tunnels. Furthermore, the energy absorption parameters are not adjustable, making it difficult to adapt to different deformation conditions of the surrounding rock. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art by providing a buffer energy-absorbing lining structure for soft rock tunnels with large deformation and its layered construction method.

[0005] The present invention achieves the above objectives through the following technical solution: a buffer energy-absorbing lining structure for a soft rock large deformation tunnel, comprising a first lining layer and a second lining layer; The first lining layer includes a first steel mesh and a soft filler layer. The first steel mesh is formed by fixing longitudinal steel bars and transverse steel bars together. The longitudinal steel bars are arranged along the length of the tunnel, and the transverse steel bars are arranged in a ring along the cross section of the tunnel. The soft filler layer is filled inside the first steel mesh. The second lining layer is located inside the first lining layer and includes a second steel mesh and a concrete filler layer. An energy-absorbing component is provided in the second lining layer. The energy-absorbing component includes a support, a first buffer, a second buffer, and a fixing plate. An installation groove is provided in the concrete filler layer. One end of the support is set in the installation groove, and the other end passes through the concrete filler layer and forms a fit with the node of the first steel mesh. The support is used to transfer the stress on the first steel mesh to the first buffer and the second buffer. The first buffer is disposed between the support and the fixed plate and applies elastic force along the axial direction of the support. The second buffer is disposed on the side of the support. The side of the support has a working surface that cooperates with the second buffer. The second buffer absorbs part of the stress transmitted by the support through the working surface.

[0006] Preferably, the first buffer includes a first elastic element, and the second buffer includes a sliding block and a second elastic element. One end of the sliding block is slidably engaged with the working surface, and the second elastic element is disposed at the other end of the sliding block and applies an elastic force toward the support to the sliding block. The working surface is a first inclined surface and is used to convert part of the axial stress on the support into a lateral component force that drives the sliding block to compress the second elastic element.

[0007] Preferably, the energy-absorbing assembly further includes an adjusting member, which is disposed in the mounting groove and used to adjust the preload of the first buffer and the second buffer. The adjusting member includes a movable plate and an adjusting operation part. The first buffer is disposed between the support and the movable plate. One end of the adjusting operation part extends to the outside of the fixed plate and is used to drive the movable plate to slide along the mounting groove to change the compression of the first buffer.

[0008] Preferably, the adjusting member further includes a pressure plate slidably disposed in the mounting groove. The movable plate has driving parts at both ends, and the driving parts have a second inclined surface that cooperates with the pressure plate. The pressure plate is disposed at the end of the second buffer member. When the movable plate slides, the second inclined surface drives the pressure plate to slide in a direction perpendicular to the sliding direction of the movable plate, so as to adjust the preload of the second buffer member.

[0009] Preferably, the nodes of the support member and the first steel mesh are connected by a cross-shaped socket, which is located at the end of the support member closest to the first steel mesh.

[0010] Preferably, multiple energy-absorbing components are provided in the same cross-section of the second lining layer and form a group. Multiple groups of energy-absorbing components are provided in the second lining layer along the tunnel length direction, and adjacent groups of energy-absorbing components are staggered along the tunnel circumference.

[0011] Preferably, the device further includes an anchor rod and a fixing member. One end of the anchor rod extends into the surrounding rock of the tunnel, and the middle part of the anchor rod passes through the gap of the first steel mesh. The fixing member is disposed in the middle part of the anchor rod and connects the anchor rod to the steel bars of the first steel mesh. When the first steel mesh is under stress, the fixing member and the anchor rod provide support for the first steel mesh.

[0012] Preferably, the anchor rod has an annular protrusion in the middle, and the fixing member includes a first mounting plate, a second mounting plate and a locking member. The first mounting plate and the second mounting plate are respectively disposed on both sides of the annular protrusion and are fixedly connected by the locking member to restrict the annular protrusion between the two.

[0013] A layered construction method for a buffer energy-absorbing lining structure for a soft rock tunnel with large deformation includes the following steps: S1 Reinforcing Mesh Pre-laying and Fixing: After the tunnel is excavated and formed, the first reinforcing mesh is laid as a whole on the inner side of the tunnel surrounding rock. First, the intersection nodes of the longitudinal and transverse reinforcing bars are tied and pre-fixed, and then all pre-fixed nodes are fully welded and reinforced to ensure the overall stability of the first reinforcing mesh. S2 Anchor Bolt Anchoring Installation: Drill anchor holes at corresponding points in the tunnel surrounding rock, insert the outer end of the anchor bolt into the anchor hole, clamp the middle annular protrusion of the anchor bolt with the two mounting plates of the fastener, and use bolts to lock the mounting plates to stably fix the middle part of the anchor bolt to the gap of the first steel mesh. Construction of the first lining layer of S3: A pre-installed template is set up inside the first steel mesh. The inside of the first steel mesh is filled with a mixture of clay and gravel. The layers are compacted and leveled to form a uniform and dense soft filler layer. During the filling and compaction process, the outer end of the support is embedded into the soft filler layer so that the cross-shaped insertion end of the support is precisely connected to the welding node of the first steel mesh. After completion, the pre-installed template is removed. S4 Second Lining Layer Forming: The second steel mesh is laid as a whole inside the first lining layer. The relative positions of the second steel mesh and each support are finely adjusted to ensure assembly accuracy. The fixed template is assembled and poured between the first lining layer and the fixed template. The concrete slurry penetrates and fills the gap between the anchor rod and the anchor hole. The concrete slurry is cured and formed into a concrete slurry layer. After curing to the required standard, the fixed template is removed. S5 Energy Absorbing Component Assembly: In the pre-set installation slot of the concrete filler layer, install the adjusting component, the first buffer component, the second buffer component and the support component in sequence, fix the fixing plate and turn the adjusting operation part to calibrate the pre-tightening force of the elastic component, complete the installation and debugging of all energy absorbing components, and the overall lining construction is completed.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. By setting a soft filler layer as the first-level energy absorption layer, the energy of the compression deformation of the surrounding rock is absorbed first. At the same time, the first and second elastic elements in the energy absorption component constitute the second-level energy absorption system. When the first steel mesh is subjected to stress, the stress is transmitted to the elastic system through the support and effectively absorbed. The two-level energy absorption mechanism works together to effectively solve the problem of insufficient energy absorption capacity of traditional lining structures.

[0015] 2. By adjusting the operating mechanism to drive the movable plate, the second inclined surface at the end of the movable plate pushes the pressure plate to slide, thereby adjusting the preload of the second elastic element. Simultaneously, the movement of the movable plate also changes the compression state of the first elastic element. The operator can flexibly adjust the energy absorption performance of the energy-absorbing component according to the actual surrounding rock pressure. 3. Multiple sets of energy-absorbing components are staggered along the length of the tunnel, so that the energy absorption effect is evenly covered throughout the entire lining structure. The anchor rods are connected to the first steel mesh through fixing parts, which supports the first steel mesh and prevents it from being over-deformed. After the anchor rods are grouted, some concrete enters the anchor hole, which further enhances the anchoring effect. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to the present invention. Figure 2 This is a schematic diagram of the structure of the second lining layer, the first steel mesh, and the energy-absorbing component in this invention; Figure 3 This is a partial structural schematic diagram of the second lining layer and energy-absorbing component in this invention; Figure 4 This is a partial structural diagram of the second lining layer, the first steel mesh, and the anchor bolts in this invention; Reference numerals: 1. First lining layer; 2. First reinforcing mesh; 3. Soft filler layer; 4. Second lining layer; 5. Energy-absorbing component; 6. Anchor bolt; 7. Fixing element; 8. Supporting element; 9. First inclined surface; 10. Cross socket; 11. Pressure plate; 12. Drive unit; 13. Adjustment operation unit; 14. Sliding block; 15. First elastic element; 16. Movable plate; 17. Second elastic element; 18. Fixing plate; 19. Mounting groove; 20. Second inclined surface; 21. Ring protrusion. Detailed Implementation

[0017] 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.

[0018] like Figures 1-4As shown, a buffer energy-absorbing lining structure for a soft rock large deformation tunnel includes a first lining layer 1 and a second lining layer 4. The first lining layer 1 includes a first steel mesh 2 and a soft filler layer 3. The first steel mesh 2 includes longitudinal steel bars and transverse steel bars. The longitudinal steel bars are arranged along the tunnel length direction, and the transverse steel bars are a ring structure along the tunnel cross section. The nodes of the longitudinal steel bars and the transverse steel bars are fixed by welding. The soft filler layer 3 is a clay structure containing crushed stone. The mass ratio of crushed stone to clay is 1:2, and the particle size of the crushed stone is 10-20mm. Using this ratio and particle size range can ensure that the soft filler layer 3 has good compressive deformation capacity and a certain structural strength. As the first-level energy-absorbing layer, when the surrounding rock undergoes compression deformation, the soft filler layer 3 absorbs part of the deformation energy through its own compression.

[0019] The second lining layer 4 is located inside the first lining layer 1. It includes a second steel mesh and a concrete filler layer. The concrete filler layer is made of C30 grade concrete. An energy-absorbing component 5 is installed in the second lining layer 4. The second steel mesh has the same structure as the first steel mesh 2, but its steel density is lower than that of the first steel mesh 2. It is necessary to ensure the strength of the second lining layer 4 and avoid the installation of the energy-absorbing component 5. The energy-absorbing component 5 includes a support member 8, a first buffer member, a second buffer member, and a fixing plate 18. The concrete filler layer has an installation groove 19. The cross-sectional shape of the installation groove 19 is rectangular, and its size matches the components of the energy-absorbing component 5. One end of the support member 8 is located in the installation groove 19, and the other end has a cross-shaped socket 10. After passing through the concrete filler layer, it is inserted into the node formed by the longitudinal and transverse steel bars in the first steel mesh 2.

[0020] The first buffer component includes a first elastic element 15. The fixing plate 18 is fixed to the concrete filler layer by anchor bolts. The first elastic element 15 applies a pre-tightening force to the support 8 in the direction of the first steel mesh 2, so that the cross-shaped socket 10 of the support 8 always keeps in close contact with the node of the first steel mesh 2. Each energy-absorbing component 5 includes two second buffer components. The two second buffer components are located on both sides of the support 8. The second buffer component is provided with a sliding block 14 and a second elastic element 17. One end of the sliding block 14 slides in cooperation with the first inclined surface 9 on the side of the support 8. The second spring is provided at the other end of the sliding block 14 and applies an elastic force to the sliding block 14 in the direction of the support 8. The inclination angle of the first inclined surface 9 is 20-30°. This angle can achieve a good balance between axial stress and lateral component force, ensuring that there is enough lateral component force to drive the sliding block 14, and avoiding the sliding block 14 from getting stuck due to excessive angle. In this embodiment, both the first elastic element 15 and the second elastic element 17 are springs.

[0021] When the first lining layer 1 is subjected to rock stress, the soft filler layer 3 first absorbs energy by compressing and deforming itself. When the first steel mesh 2 is subjected to stress, the stress is transmitted to the mounting groove 19 through the support member 8. Part of the energy is absorbed axially by the first elastic member 15, and the other part is pushed by the component of the force along the first inclined surface 9 to push the sliding block 14 to compress the second elastic member 17, thus achieving a second energy absorption. The two-stage energy absorption mechanism works together to significantly improve the buffer energy absorption capacity of the lining structure.

[0022] The energy-absorbing assembly 5 also includes an adjusting component, which includes a movable plate 16, a pressure plate 11, and an adjusting operation part 13. In this embodiment, the adjusting operation part 13 is an adjusting bolt. Two pressure plates 11 and adjusting operation parts 13 are provided, and both the pressure plate 11 and the movable plate 16 are slidably disposed in the mounting groove 19. The sliding direction of the pressure plate 11 is perpendicular to the sliding direction of the movable plate 16. The two ends of the movable plate 16 have driving parts 12, and the driving parts 12 have a second inclined surface 20 that cooperates with the pressure plate 11. The two ends of the second elastic member 17 respectively abut against the sliding block 14 and the pressure plate 11, and the two ends of the first elastic member 15 respectively abut against the support member 8 and the movable plate. The adjusting operating part 13 is threadedly connected to the fixed plate 18, and one end of the adjusting operating part 13 abuts against the movable plate 16. By rotating the adjusting operating part 13, the movable plate 16 can be pushed to slide along the mounting groove 19. The second inclined surface 20 at the end of the movable plate 16 pushes the pressure plate 11 to slide in a direction perpendicular to the sliding direction of the movable plate 16, thereby adjusting the preload of the second elastic element 17. At the same time, the movement of the movable plate 16 also changes the compression state of the first elastic element 15. The operator can flexibly adjust the energy absorption performance of the energy absorption component 5 according to the actual monitored surrounding rock pressure data, so that the lining structure can adapt to different geological conditions.

[0023] Multiple energy-absorbing components 5 are provided in a certain cross section of the second lining layer 4. In this embodiment, each cross section is provided with one energy-absorbing component 5, which is evenly distributed along the tunnel circumference. All the energy-absorbing components 5 in this cross section are set as a group. A group of energy-absorbing components 5 is provided every 20-30m along the tunnel length direction of the second lining layer 4. Adjacent groups of energy-absorbing components 5 are staggered with a stagger angle of 30° to ensure that the energy absorption effect evenly covers the entire lining structure along the tunnel length direction.

[0024] An anchor rod 6 is also provided in the area between two adjacent sets of energy-absorbing components 5. One end of the anchor rod 6 is located in the concrete filler layer, and the other end extends into the surrounding rock of the tunnel. The middle part of the anchor rod 6 passes through the gap of the first steel mesh 2 and is located between two adjacent longitudinal steel bars. The middle part of the anchor rod 6 has an annular protrusion 21. The fixing member 7 includes two mounting plates fixed by locking members. In this embodiment, the locking members are bolts, which are used to restrict the annular protrusion 21 between the two mounting plates. When the first steel mesh 2 is subjected to rock stress, the fixing member 7 and the anchor rod 6 provide support for part of the first steel mesh 2, so that the first steel mesh 2 will not be excessively deformed. At the same time, the part of the anchor rod 6 that extends into the surrounding rock forms an integral whole with the surrounding rock through grouting, which further enhances the stability of the surrounding rock.

[0025] This embodiment provides a layered construction method for the above-mentioned buffer energy-absorbing lining structure of soft rock large deformation tunnel. The specific steps are as follows: S1 Reinforcing Mesh Pre-laying and Fixing: After the tunnel is excavated to the design outline, the surface debris and loose rock are cleaned, and the first reinforcing mesh 2 is laid as a whole. First, the longitudinal and transverse reinforcing bars are tied and pre-fixed with tie wire, and then all the cross nodes are fully welded to ensure that the reinforcing mesh is not loose or detached.

[0026] S2 Anchor Bolt Anchoring Installation: Drill holes at the marked points in the surrounding rock according to the design spacing. After cleaning the holes, insert the anchor bolt 6 and inject anchoring mortar into the anchoring holes. After the mortar has initially set, use two mounting plates to enclose and clamp the annular protrusion 21 in the middle of the anchor bolt 6 and lock it with high-strength bolts to form an integral limiting structure between the anchor bolt 6 and the first steel mesh 2.

[0027] Construction of the first lining layer of S3: Erect pre-installed formwork, leave space between the formwork and the first steel mesh 2 for compaction of the fill material, fill the mixed gravel and clay fill material in layers, each layer is 20-30cm thick, compact and level layer by layer to ensure the compaction degree of the fill material is ≥95%, during the compaction process, accurately align the support component 8 so that the end cross-shaped insertion 10 is connected to the steel mesh node, after compaction is completed, let it stand for 24 hours for curing, and then remove the pre-installed formwork.

[0028] Forming of the second lining layer S4: Lay the second steel mesh, fine-tune the position of the steel mesh to avoid the end structure of the support member 8, assemble and fix the template, pour C30 concrete filler in layers, fill the gap of the anchor hole of the anchor rod 6 with the concrete slurry by gravity, ensure that the anchor rod 6 is anchored tightly, vibrate the concrete in layers to make it dense, cure the whole for 48 hours, remove the fixed template after the strength reaches 70% of the design, and repair the groove of the installation slot 19.

[0029] S5 Energy Absorbing Component Assembly: Install the remaining accessories of the energy absorbing component 5 in the mounting slot 19 in sequence. Adjust the operating part 13 by turning the wrench to calibrate the pre-tightening compression of the first elastic element 15 and the second elastic element 17 to ensure that the bidirectional buffer structure is in the optimal working state. Complete the assembly and debugging of all energy absorbing components 5 one by one, and the overall lining construction is completed.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0031] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A buffer energy-absorbing lining structure for a soft rock tunnel with large deformation, comprising a first lining layer (1) and a second lining layer (4), characterized in that: The first lining layer (1) includes a first steel mesh (2) and a soft filler layer (3). The first steel mesh (2) is formed by fixed connection of longitudinal steel bars and transverse steel bars. The longitudinal steel bars are arranged along the tunnel length direction, and the transverse steel bars are arranged in a ring along the tunnel cross section. The soft filler layer (3) is filled in the first steel mesh (2). The second lining layer (4) is located inside the first lining layer (1), and includes a second steel mesh and a concrete filler layer. The second lining layer (4) is provided with an energy-absorbing component (5). The energy-absorbing component (5) includes a support (8), a first buffer, a second buffer, and a fixing plate (18). The concrete filler layer is provided with an installation groove (19). One end of the support (8) is set in the installation groove (19), and the other end passes through the concrete filler layer and forms a fit with the node of the first steel mesh (2). The support (8) is used to transfer the stress on the first steel mesh (2) to the first buffer and the second buffer. The first buffer is disposed between the support (8) and the fixed plate (18) and applies elastic force along the axial direction of the support (8). The second buffer is disposed on the side of the support (8). The side of the support (8) is provided with a working surface that cooperates with the second buffer. The second buffer absorbs part of the stress transmitted by the support (8) through the working surface.

2. The buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to claim 1, characterized in that, The first buffer includes a first elastic element (15), and the second buffer includes a sliding block (14) and a second elastic element (17). One end of the sliding block (14) is slidably engaged with the working surface, and the second elastic element (17) is disposed at the other end of the sliding block (14) and applies an elastic force toward the support (8) to the sliding block (14). The working surface is a first inclined surface (9) and is used to convert part of the axial stress on the support (8) into a lateral component force that drives the sliding block (14) to compress the second elastic element (17).

3. The buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to claim 1, characterized in that, The energy-absorbing component (5) also includes an adjusting member, which is disposed in the mounting groove (19) and used to adjust the preload of the first buffer and the second buffer. The adjusting member includes a movable plate (16) and an adjusting operation part (13). The first buffer is disposed between the support member (8) and the movable plate (16). One end of the adjusting operation part (13) extends to the outside of the fixed plate (18) and is used to drive the movable plate (16) to slide along the mounting groove (19) to change the compression amount of the first buffer.

4. The buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to claim 3, characterized in that, The adjusting component also includes a pressure plate (11) slidably disposed in the mounting groove (19). The movable plate (16) has a driving part (12) at both ends. The driving part (12) has a second inclined surface (20) that cooperates with the pressure plate (11). The pressure plate (11) is disposed at the end of the second buffer. When the movable plate (16) slides, the second inclined surface (20) drives the pressure plate (11) to slide in a direction perpendicular to the sliding direction of the movable plate (16) to adjust the preload of the second buffer.

5. The buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to claim 1, characterized in that, The nodes of the support member (8) and the first steel mesh (2) are connected by a cross-shaped socket (10), which is located at one end of the support member (8) near the first steel mesh (2).

6. The buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to claim 1, characterized in that, Multiple energy-absorbing components (5) are provided in the same cross section of the second lining layer (4) and form a group. Multiple groups of energy-absorbing components (5) are provided in the second lining layer (4) along the tunnel length direction, and adjacent groups of energy-absorbing components (5) are staggered along the tunnel circumference.

7. The buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to claim 1, characterized in that, It also includes an anchor rod (6) and a fixing member (7). One end of the anchor rod (6) extends into the surrounding rock of the tunnel, and the middle part of the anchor rod (6) passes through the gap of the first steel mesh (2). The fixing member (7) is set in the middle of the anchor rod (6) and connects the anchor rod (6) to the steel bars of the first steel mesh (2). When the first steel mesh (2) is under force, the fixing member (7) and the anchor rod (6) provide support for the first steel mesh (2).

8. The buffer energy-absorbing lining structure for a soft rock tunnel with large deformation according to claim 6, characterized in that, The anchor rod (6) has an annular protrusion (21) in the middle. The fixing member (7) includes a first mounting plate, a second mounting plate and a locking member. The first mounting plate and the second mounting plate are respectively disposed on both sides of the annular protrusion (21) and fixedly connected by the locking member to restrict the annular protrusion (21) between the two.

9. A layered construction method for a buffer energy-absorbing lining structure for a soft rock tunnel with large deformation, used for constructing the lining structure according to any one of claims 1-8, characterized in that, Includes the following steps: S1 Reinforcing Mesh Pre-laying and Fixing: After the tunnel is excavated and formed, the first reinforcing mesh (2) is laid as a whole on the inner side of the tunnel surrounding rock. First, the intersection nodes of the longitudinal and transverse reinforcing bars are tied and pre-fixed, and then all pre-fixed nodes are fully welded and reinforced to ensure the overall forming stability of the first reinforcing mesh (2). S2 Anchor Bolt Anchoring Installation: Drill anchor holes at corresponding points in the surrounding rock of the tunnel, insert the outer end of the anchor bolt (6) into the anchor hole, clamp the middle annular protrusion (21) of the anchor bolt (6) with the two mounting plates of the fixing piece (7), and use bolts to lock the mounting plates to stably fix the middle part of the anchor bolt (6) at the gap of the first steel mesh (2); Construction of the first lining layer of S3: A pre-installed template is set up inside the first steel mesh (2), and clay and gravel mixed filler is filled into the first steel mesh (2). The filler is compacted and leveled layer by layer to form a uniform and dense soft filler layer (3). During the filling and compaction process, the outer end of the support (8) is embedded into the soft filler layer (3) so that the cross-shaped plug (10) at the end of the support (8) is accurately connected to the welding node of the first steel mesh (2). After completion, the pre-installed template is removed. S4 Second Lining Layer Formation: The second steel mesh is laid as a whole inside the first lining layer (1), the relative position of the second steel mesh and each support (8) is finely adjusted to ensure assembly accuracy, the fixed template is assembled, concrete filler is poured between the first lining layer (1) and the fixed template, the concrete slurry penetrates and fills the gap between the anchor rod (6) and the anchor hole, the concrete filler layer is solidified and formed, and the fixed template is removed after curing meets the standards. S5 Energy Absorption Component Assembly: In the pre-installed groove (19) of the concrete filler layer, install the adjustment component, the first buffer component, the second buffer component and the support component (8) in sequence, fix the fixing plate (18) and turn the adjustment operation part (13) to calibrate the pre-tightening force of the elastic component, complete the installation and debugging of all energy absorption components (5), and the overall lining construction is completed.

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