Bionic toughness tunnel structure with variable stiffness and graded coordinated deformation and method

Abstract

The invention relates to a bionic tough tunnel structure with variable stiffness and graded coordinated deformation and a method. The bionic tough tunnel structure comprises a scale mechanical protection layer, a muscle deformation coordination layer and a spine segmented bearing layer which are sequentially arranged from outside to inside, the scale mechanical protection layer comprises variable stiffness induction rings and primary linings which are arranged in a staggered manner in the extension direction of the bionic tough tunnel structure; the muscle deformation coordination layer is a rubber deformation buffer layer; the spine segmented bearing layer is of a multi-section structure, each section comprises a socket assembly type concrete pipe section and a displacement connection joint, the displacement connection joint comprises a socket component and a rubber cushion pad, the socket assembly type concrete pipe sections and the socket component are integrally formed, and the rubber cushion pad is arranged in the socket assembly type concrete pipe sections. A shear key of the front socket splicing type concrete pipe joint and a groove in the tail of the rear socket splicing type concrete pipe joint are formed, the rubber buffer cushion is installed in the groove, and an axial displacement space is reserved between every two adjacent socket splicing type concrete pipe joints. Compared with the prior art, the anti-seismic and anti-error capabilities of the tunnel are improved.

Description

Technical Field

[0001] This invention relates to the field of tunnel structures, and in particular to a biomimetic tough tunnel structure and method that combines variable stiffness and graded coordinated deformation. Background Technology

[0002] Currently, an increasing number of tunnel projects inevitably traverse areas prone to high-intensity earthquakes. Following earthquakes, multiple tunnels crossing active fault zones have experienced severe damage, including lining collapses, misalignments, and cracks. This not only poses a serious threat to the structural safety of the tunnels but also causes traffic congestion in disaster areas, hindering subsequent rescue efforts. Therefore, improving the seismic performance of tunnels and ensuring their stable operation under earthquake loads is a key research area in tunnel engineering technology.

[0003] The design of seismically resilient tunnel structures aims to improve the adaptability and overall stability of tunnels under seismic loads and fault slippage by optimizing the stress state and deformation characteristics of the tunnel structure. This allows for better graded dissipation of seismic energy and gradient transfer of loads to the tunnel structure, enabling it to maintain or quickly restore normal function after an earthquake, thus ensuring safe tunnel operation. However, current traditional designs for resilient tunnels crossing active faults often only consider a single seismic load level and typically employ a single seismic isolation structure within the overall tunnel structure. Existing research indicates that the displacement of a fault during slippage is mainly concentrated in the fault core, resulting in significant deformation within a small area, which can easily cause severe damage to the tunnel structure in that region. Therefore, there is an urgent need to develop a resilient tunnel structure capable of withstanding multiple seismic load levels to rationally optimize the stress and controllable deformation of the tunnel structure. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a biomimetic tough tunnel structure and method that combines variable stiffness and graded coordinated deformation. Through scientific and reasonable design and technical measures, the safety performance of tunnels under seismic action and fault faulting is improved, thereby protecting people's lives and property and ensuring the stable operation of transportation infrastructure.

[0005] The objective of this invention can be achieved through the following technical solutions: A biomimetic resilient tunnel structure combining variable stiffness and graded coordinated deformation includes, from the outside to the inside, a scale-like mechanical protective layer, a muscle deformation coordinating layer, and a spine segmented load-bearing layer. The scale-like mechanical protective layer includes variable stiffness induction rings and an initial lining arranged alternately in the extension direction of the biomimetic resilient tunnel structure. The muscle deformation coordinating layer is a rubber deformation buffer layer. The spine segmented load-bearing layer is a multi-segment structure, each segment including a socket-assembled concrete pipe section and a displacement traction connector. The displacement traction connector includes a socket component and a rubber buffer pad. The socket-assembled concrete pipe section is integrally formed with the socket component, forming a shear key for the preceding socket-assembled concrete pipe section and a groove at the tail of the following socket-assembled concrete pipe section. The rubber buffer pad is installed in the groove, and axial displacement space is left between two adjacent socket-assembled concrete pipe sections.

[0006] Inspired by the snake's ability to move flexibly using its unique intervertebral joints, ligaments, and muscles, this invention proposes a stiffness-adaptive flexible joint design for tunnels based on the principles of variable stiffness and graded induced deformation. This design incorporates adaptive coordinated deformation transfer under minor earthquakes and fault faults, and adaptive induced zonal isolation failure design under major earthquakes and fault faults. These features effectively ensure that during operation, the tunnel structure can prevent large deformation failure through dynamic deformation transfer and dynamic load dispersion under seismic and fault fault actions. Simultaneously, the tunnel structure system is systematically divided into different sections, enabling autonomous zonal isolation failure when large deformation failure is unavoidable, thus maximizing the protection of the main tunnel structure. The proposed tunnel structure possesses adaptive variable stiffness and graded coordinated deformation capabilities. This tunnel structure can maintain or quickly restore normal function after an earthquake, ensuring tunnel operational safety and aligning with the toughness design concept of tunnel structures.

[0007] In this invention, the tunnel structure design draws inspiration from the biological structural characteristics of snakes. By rationally optimizing the tunnel's structural form, the overall structure of the tunnel traversing active faults exhibits better adaptability and stability under the coupling effects of seismic and faulting. Similar to the highly free and adaptive intervertebral joints and ligaments, and the highly coordinated, adaptive, and resilient muscle structures of snakes, this invention primarily introduces stiffness-adaptive flexible joints with deformation thresholds and flexible buffer-type muscle deformation coordination layers to induce zonal isolation of damage, absorb dissipated energy, and facilitate gradient-transfer deformation. The specific design concept of the biomimetic snake-like resilient tunnel structure is as follows: The initial support structure of the tunnel resembles the scales of a snake, providing mechanical protection and preventing further loosening and collapse of the surrounding rock under seismic and faulting forces. It serves as the first line of defense against external physical damage. In addition to the general articular processes, the snake's vertebrae have a pair of vertebral arch protrusions at the anterior end of the myelin arch, which fit onto the concave depression at the posterior end of the previous myelin arch. This makes the vertebrae of the snake tightly and flexibly connected. The secondary lining structure of the tunnel, consisting of interlocking concrete pipe sections, is similar to the vertebral skeleton of a snake. It possesses sufficient strength and stiffness, reasonable segmentation, and good static and dynamic load resistance. It is the main load-bearing structure during the tunnel's service life, bearing most of the load exerted by the surrounding rock on the tunnel support structure under seismic and faulting forces. Simultaneously, the interlocking structure and the displacement-traction joint work together... This work can effectively improve the robustness and flexibility of the secondary lining structure connection. Drawing on the excellent deformation adaptability of the intervertebral joints and ligament structures of snakes, a stiffness-adaptive flexible joint with deformation threshold is proposed. The variable stiffness induction ring is the joint of the initial support structure, and the displacement traction joint is the joint of the secondary lining structure. It has the function of stiffness adaptive adjustment under different levels of seismic action and fault action, so as to maximize the safety of the overall tunnel structure. Drawing on the muscle structure of snakes and its excellent synergistic toughness, a toughness buffer type muscle deformation coordination layer structure is proposed. It plays a coordinating and dispersing role in the excessive deformation and stress that occur in the initial support layer and secondary lining layer of the tunnel under seismic and fault action. At the same time, it also serves as a waterproof layer and has a waterproof function. It is the main structure for the tunnel to absorb dissipation capacity and gradient transfer of excessive deformation and load.

[0008] The core of this invention is to accurately characterize the working mechanism of the stiffness-adaptive flexible joint, the muscle deformation coordination layer structure that absorbs and dissipates energy and adaptively coordinates and transmits deformation in the tunnel structure, and the adaptive induction of zonal isolation failure. In this invention, the scale mechanical protective layer uses the principle of variable stiffness to induce structural deformation to adapt to the fault fault action; the muscle deformation coordination layer, while coordinating the deformation transmitted by the scale mechanical protective layer, widens the displacement space of the tunnel structure in the fault core area; the vertebral segmented bearing layer transmits the concentrated deformation generated by the tunnel in the fault core area to both ends of the tunnel through the traction displacement joint, while effectively realizing the dynamic dispersion of load and avoiding concentrated failure of the tunnel due to excessive local deformation and local stress.

[0009] Furthermore, the elastic modulus and shear modulus of the rubber buffer pad are distributed in a gradient along the longitudinal direction of the tunnel. The elastic modulus and shear modulus are smaller at the socket-assembled concrete pipe sections near the active fracture area, and larger at the socket-assembled concrete pipe sections away from the active fracture area.

[0010] Furthermore, the contact surfaces of the shear key and the groove at the tail of the subsequent socket-assembled concrete pipe section are coated with lubricant to form a sliding surface.

[0011] Furthermore, the rubber cushioning pad covers the bottom surface, the two opposite sides, and the inner side of the groove.

[0012] Furthermore, the variable stiffness induction ring is a rubber vibration isolation pad, used to form a region of abrupt stiffness change, thereby producing an induction effect.

[0013] Furthermore, the initial lining is a concrete structure and is a multi-section structure. The variable stiffness induction ring is installed between two adjacent sections of the initial lining through a caulking process, so that relative deformation can occur between different sections of the initial lining.

[0014] Furthermore, the muscle deformation coordination layer, which runs through the entire biomimetic resilient tunnel structure, is located between the scale-like mechanical protective layer and the spine segmental load-bearing layer. It possesses high flexibility and high buffering properties, enabling adaptive and coordinated deformation transfer. Under seismic and fault coupling, the flexible buffering characteristics of the muscle deformation coordination layer can widen the structural displacement surface, absorb and dissipate energy, and transfer excessive deformation and loads, giving each layer of the tunnel structure greater lateral and longitudinal displacement space, while also providing waterproofing. Similar to how a snake's highly coordinated and resilient muscle structure prevents fatigue damage when subjected to repeated static and dynamic loads, the muscle deformation coordination layer effectively ensures the dynamic deformation transfer and load dispersion of each layer of the fault-crossing tunnel under seismic and fault coupling, preventing tunnel structure damage due to localized excessive deformation and loads.

[0015] Furthermore, under conditions of minor earthquakes and small displacements, the biomimetic resilient tunnel structure utilizes the combined function of the scale-like mechanical protective layer and the muscle deformation coordination layer. The scale-like mechanical protective layer, with its combination of rigidity and flexibility, allows for relative displacement between different segments of the initial lining, absorbing vibration and deformation. The muscle deformation coordination layer, with its high synergy and high toughness, further absorbs and disperses vibration and deformation.

[0016] Furthermore, under the condition of a large earthquake and displacement, the biomimetic resilient tunnel structure induces displacement in the core area of ​​the tunnel by the scale mechanical protective layer; the vertebral segment bearing layer transmits the displacement to the adjacent socket-assembled concrete pipe section through the displacement traction joint, forming a traction cross line in the core area of ​​the tunnel.

[0017] Furthermore, the biomimetic resilient tunnel structure is designed with structural parameters based on the seismic hazard of the area to be arranged.

[0018] Furthermore, each lining segment unit of the socket-assembled concrete pipe section secondary lining structure can be divided into a main pipe section, a protruding pipe section, and a recessed pipe section. These three parts are continuously cast to form a lining segment unit. The outer diameters of the protruding pipe section and the recessed pipe section are equal, forming the socket and spigot of the concrete pipe section. Inserting the protruding pipe section into the recessed pipe section connects the lining segments. By arranging them end to end, a prefabricated tunnel secondary lining structure is finally formed. Similar to the high-strength, high-rigidity skeletal structure of a snake, which allows the snake's body to maintain its morphological stability under large external pressure, and the protrusions and depressions on the surface of the snake's vertebrae, which allow the vertebrae to be firmly connected, the socket-assembled concrete pipe section secondary lining structure can bear the main static and dynamic loads of the fault-crossing tunnel structure under the coupling of seismic and fault forces, ensuring the seismic and fault-resistant stability of the tunnel structure.

[0019] Furthermore, the shear key and groove design of the socket component allows displacement to be transferred step by step between different socket-assembled concrete pipe sections in the secondary lining structure, thereby achieving the design goal of dispersing concentrated displacement; the rubber buffer pad effectively avoids potential stress concentration damage to the tunnel structure while leaving displacement space to adapt to fault dislocation; the reserved sliding surface allows relative displacement between pipe sections, improving the flexibility of the spine segment bearing layer and thus avoiding local damage to the tunnel structure.

[0020] This invention also provides a design method for a biomimetic tough tunnel structure that combines variable stiffness and graded coordinated deformation, comprising: designing structural parameters using a multi-objective optimization algorithm, wherein the processing steps of the multi-objective optimization algorithm include: The internal forces and deformations of the socket-assembled concrete pipe sections under the displacement traction joint with different compressive stiffness, shear stiffness, and rotational stiffness were obtained through parametric finite element numerical simulation of the biomimetic resilient tunnel structure. An optimization model of the deformation response and internal force distribution of the tunnel pipe sections was established. The optimization model uses the structural internal force response of the socket-assembled concrete pipe sections and the relative rotation angle and displacement deformation of two adjacent socket-assembled concrete pipe sections as objective functions considering safety and functionality; and uses the maximum allowable displacement and the maximum design strength of the rubber material as constraints. The calculation expressions for the security and functionality objective functions, including the functionality objective function Q and the security objective function P, are as follows: In the formula, For the first Deformation of pipe section angle, For the first and The difference in deflection between adjacent pipe sections The number of socket-assembled concrete pipe sections; In the formula, and These represent the bending moment and shear force at the cross-sections along the tunnel route, respectively.

[0021] The optimization model is solved to obtain the optimal control solution for the deformation and internal force distribution of the tunnel structure under strong earthquake and dislocation coupling, which conforms to the design specifications. This allows for the determination of the elastic modulus, shear modulus, and equivalent damping ratio parameters of the rubber deformation buffer layer and rubber buffer pad.

[0022] Compared with the prior art, the present invention has the following advantages: (1) This invention draws on the structural characteristics of a snake's body to optimize the design of the composite lining structure of tunnels, thereby improving the tunnel's seismic and fault resistance capabilities. A biomimetic tough tunnel structure with both variable stiffness and graded coordinated deformation is proposed, effectively solving the problem that traditional fault-crossing tunnels cannot effectively cope with large-scale fault displacement under strong earthquake-dislocation coupling in seismic fortification. For different seismic load levels, a multi-level induction structure is designed for two-level induction.

[0023] Under minor earthquakes and minor faults, the scale mechanical protective layer and the muscle deformation coordination layer work together. By utilizing the combination of rigidity and flexibility and the self-adaptive stiffness adjustment characteristics of the scale mechanical protective layer, and the self-adaptive coordination characteristics of the muscle deformation coordination layer in transmitting deformation and expanding the deformation and displacement space of the tunnel, they can effectively absorb and dissipate energy, transmit loads and deformations under minor earthquakes and minor faults, and ensure that the tunnel structure is safe, stable and undamaged under minor earthquakes and minor faults. Under the influence of a major earthquake and fault, the scale mechanical protective layer mainly induces the interaction between the tunnel structure and the surrounding rock in the fault core area, actively inducing the location of tunnel fault displacement and failure in the fault core area. The joint structure automatically fails after reaching the threshold to induce zoned isolation failure of the tunnel. The spine segmented bearing layer transmits the displacement to the adjacent tunnel segment through displacement traction joint after the tunnel segment is displaced, thereby forming a traction cross line on the tunnel structure in the fault core area. This ensures that the tunnel structure in the fault core area and other potentially severely deformed or high-bearing sections actively disperses and concentrates displacement under the influence of a major earthquake and fault, and forms zoned isolation failure.

[0024] Ultimately, the goal is to achieve reasonable stress, controllable deformation, and controllable damage of tunnel structures under seismic action and fault faulting based on adaptive variable stiffness and graded coordinated deformation functions. This ensures the toughness of the tunnel structure in maintaining or quickly restoring normal function after an earthquake disaster, and guarantees the safety of the overall tunnel structure under the coupled action of seismic action and fault faulting. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a biomimetic tough tunnel structure that combines variable stiffness and graded coordinated deformation, provided in an embodiment of the present invention. Figure 2 for Figure 1 Section 1-1, i.e., schematic diagram of the cross-section of the displacement traction joint; Figure 3 for Figure 1 Sections 1-2, i.e., schematic diagram of the cross-section of the variable stiffness induced ring; Figure 4 for Figure 1 Sections 1-3 are schematic diagrams of the general cross-section of the tunnel body; Figure 5 This is a three-dimensional schematic diagram of a multi-segment tunnel provided in an embodiment of the present invention; Figure 6 This is a forward three-dimensional schematic diagram of a single tunnel segment provided in an embodiment of the present invention; Figure 7 This is a three-dimensional back-facing schematic diagram of a single tunnel segment provided in an embodiment of the present invention; Figure 8 This is a three-dimensional schematic diagram of a tunnel bottom segment provided in an embodiment of the present invention; Figure 9 is a schematic diagram of a tunnel structure bearing mechanism provided in an embodiment of the present invention, wherein (a) is the normal state, (b) is the tensile state, (c) is the compressive state, (d) is the shear state, and (e) is the bending state. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0031] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] Example 1 like Figures 1-4 As shown, this embodiment provides a biomimetic resilient tunnel structure that combines variable stiffness and graded coordinated deformation. It includes a scale-like mechanical protective layer, a muscle deformation coordination layer, and a spine segmented load-bearing layer arranged sequentially from the outside to the inside. The scale-like mechanical protective layer includes variable stiffness induction rings 5 ​​and a primary liner 1 arranged alternately in the extension direction of the biomimetic resilient tunnel structure. The muscle deformation coordination layer is a rubber deformation buffer layer 2. The spine segmented load-bearing layer is a multi-segment structure, each segment including a socket-assembled concrete pipe section 3 and a displacement traction connector 4. The displacement traction connector 4 includes a socket member 41 and a rubber buffer pad 42. The socket-assembled concrete pipe section 3 and the socket member 41 are integrally formed to form a shear key of the previous socket-assembled concrete pipe section 3 and a groove at the tail of the next socket-assembled concrete pipe section 3. The rubber buffer pad 42 is installed in the groove, and an axial displacement space is left between two adjacent socket-assembled concrete pipe sections 3.

[0033] The following section will mainly describe the technical solution from the perspective of the structure and function of each part of the biomimetic resilient tunnel.

[0034] like Figures 5-8As shown, the scale-like mechanical protective layer includes a variable stiffness induction ring 5 and a primary lining 1. The variable stiffness induction ring 5 and the tunnel primary lining 1 are arranged alternately and integrally formed. The variable stiffness induction ring 5 is composed of a whole ring of rubber vibration isolation pads, which are staggered with the lining. The variable stiffness induction ring 5 forms a stiffness change region in the overall structure through the stiffness regulation mechanism of the rubber vibration isolation pads, thereby inducing displacement response on the structure. The primary lining 1 is a concrete structure used to control the stress release and deformation of the surrounding rock.

[0035] The muscle deformation coordination layer is composed of a rubber deformation buffer layer 2 and runs through the entire tunnel structure. It is located between the scale mechanical protection layer and the spine segment bearing layer. It utilizes its soft properties to widen the structural displacement surface, giving the structure a larger displacement space.

[0036] The vertebral segmental bearing layer includes socket-assembled concrete pipe sections 3 and displacement traction joints 4. The displacement traction joint 4 is composed of a socket member 41 and a rubber buffer pad 42, with a reserved sliding surface. The vertebral segmental bearing layer has the function of inducing and transmitting displacement in the longitudinal direction of the tunnel. The local displacement experienced by the socket-assembled concrete pipe section 3 can be transmitted step by step along the displacement traction joint, forming a displacement traction transition line to achieve the purpose of protecting the tunnel.

[0037] The socket-jointed concrete pipe section 3 includes an inner pipe and an outer pipe, with the outer diameter of the inner pipe equal to the inner diameter of the outer pipe. The inner and outer pipes have a certain displacement difference, forming the socket and spigot of the concrete pipe section. Adjacent socket-jointed concrete pipe sections 3 are connected via the socket to form the shear key and groove of the socket component 41. A rubber buffer pad 42 is placed between the shear key and the groove. The main bodies of the socket-jointed concrete pipe sections 3 are connected by a reserved sliding surface. The shear force transmission and displacement dissipation collaborative design of the shear key and groove of the socket component 41 allows displacement to be transmitted between different socket-jointed concrete pipe sections 3, thereby achieving the purpose of dispersing concentrated displacement. The rubber buffer pad 42, while providing displacement space to bear fault dislocations, effectively avoids damage caused by stress concentration. The reserved sliding surface allows relative displacement between the pipe sections 3, thus avoiding localized damage.

[0038] The rubber buffer pad 42 adjusts its elastic modulus and shear modulus according to the principle of variable stiffness. Its elastic modulus and shear modulus are distributed in a gradient along the longitudinal direction of the tunnel, and the gradual transfer of displacement is achieved through stiffness control. Near the active fault, the deformation is large, so a smaller elastic modulus and shear modulus are selected; further away from the active fault, the deformation is small, so a larger elastic modulus and shear modulus are selected. That is, a low modulus near the fault zone and a high modulus far from the fault zone are adopted to ensure coordinated deformation of the entire tunnel. The tunnel is subjected to displacement faulting by the scale mechanical protective layer. The displacement of pipe section 3 is induced and borne by the displacement traction joint 4 between the pipe section and adjacent pipe sections, and the displacement is transferred to adjacent pipe sections.

[0039] The contact surfaces of the shear key and the groove at the tail of the subsequent socket-assembled concrete pipe section 3 are coated with lubricant to form a sliding surface.

[0040] Rubber cushioning pad 42 covers the bottom surface of the groove, the two opposite sides, and the inner side.

[0041] The aforementioned scheme proposes a biomimetic resilient tunnel structure that combines variable stiffness and graded coordinated deformation. It adheres to the principle of phased seismic fortification for tunnels traversing active faults, and incorporates seismic resilience design for both minor earthquakes with minor faults and major earthquakes with major faults. The technical solution and seismic principles of the biomimetic resilient tunnel will be elaborated in detail below, based on the phased seismic fortification principle for tunnels traversing active faults.

[0042] In biomimetic resilient tunnel structures, by setting up graded displacement-inducing structures and deploying stiffness-adaptive flexible joints with reasonable joint deformation thresholds, the joints automatically fail after reaching the limit threshold. This allows the tunnel structure to adaptively and coordinately transmit deformation without damage under small earthquakes and small faults, and to adaptively induce zonal isolation failure under large earthquakes and large faults to ensure overall stability. Ultimately, this minimizes the impact of seismic action and fault faulting on the main tunnel structure and improves the tunnel's adaptability to large deformations in the fault core area.

[0043] Under minor earthquakes and faults, the scale mechanical protective layer and the muscle deformation coordination layer work together. The scale mechanical protective layer, with its combination of rigidity and flexibility, allows for relative displacement between different segments of the initial lining 1. The muscle deformation coordination layer expands the displacement space of the tunnel structure in the fault core area, effectively absorbing and dissipating energy, transferring loads and deformations, and protecting the safe operation of the tunnel.

[0044] In the event of a major earthquake and fault, the scale mechanical protective layer induces the interaction between the tunnel structure and the fault geology at the fault core area, causing the tunnel structure in the fault core area to shift. After the segmented bearing layer bears the dislocation, it transmits the displacement to the adjacent segments through the displacement traction joint, thereby forming a displacement transmission path in the fault core area, effectively preventing local damage to the tunnel and ensuring the safety of the tunnel structure.

[0045] Example 2 Based on the above-mentioned biomimetic resilient tunnel structure that combines variable stiffness and graded coordinated deformation, the specific implementation steps in a certain project are as follows: S1. Identify active faults that pose a potential hazard to tunnel engineering. First, based on parameters such as the fault's activity nature, scale, slip rate, and historical seismic activity, combined with regional tectonic stress field and fault activity evaluation, obtain the potential magnitude of the fault through a probabilistic statistical model. According to the "Standard for Seismic Design of Buildings" (GB / T 50011-2010), earthquakes are classified into three levels according to their probability of occurrence: minor earthquakes (frequent earthquakes, with a 50-year exceedance probability of approximately 63%), moderate earthquakes (design earthquakes, with a 50-year exceedance probability of approximately 10%), and major earthquakes (rare earthquakes, with a 50-year exceedance probability of approximately 2%~3%). Based on empirical statistical models, the empirical relationship between near-surface rupture parameters (length, width, area, and dislocation amount) of different fault types and earthquake magnitude is obtained by statistically analyzing surface rupture data of earthquake events. A functional relationship is established between earthquake magnitude and near-surface rupture parameters, that is, near-surface fault dislocation is described as a function of magnitude, rupture length, rupture width, and rupture area, etc., to obtain the corresponding graded fault dislocation amount under different earthquake magnitudes, thereby realizing the simulation of fault dislocation mode of strong earthquake-dislocation coupling.

[0046] Based on the "China Seismic Ground Motion Parameter Zoning Map" (GB 18306-2015), the corresponding seismic intensities for minor, moderate, and major earthquakes were determined. Combined with actual engineering site conditions, design ground motion parameters such as peak ground acceleration and acceleration response spectrum were determined. Through stochastic process simulation and spectral matching technology, graded ground motion acceleration time history curves with physical rationality and engineering applicability were artificially synthesized, thereby simulating the strong earthquake mode in strong earthquake-dislocation coupling.

[0047] Finally, the design load level of the strong earthquake-dislocation coupling effect was obtained after quantification.

[0048] S2. Based on tunnel engineering design specifications, engineering experience, and actual needs, considering the permanent loads, variable loads, and accidental loads borne by the tunnel structure, a two-dimensional finite element numerical simulation based on the load-structure method is conducted to calculate the internal forces of the tunnel lining structure and perform reinforcement verification. The optimal materials, cross-sectional forms, and dimensions of the main tunnel structure are preliminarily determined. Then, based on the seismic design specifications for tunnel engineering and the analytical theory of tunnel damping layers, the design parameters of the rubber deformation buffer layer 2 in the muscle deformation coordination layer and the rubber buffer pad 42 in the displacement traction joint 4 are preliminarily determined. A two-dimensional and three-dimensional numerical model of a biomimetic tough tunnel considering the coupling effect of near-fault strong ground motion and large dislocation is established. The internal forces and deformations of the segmented assembled concrete lining pipe section 3 are solved, and the internal forces and deformations are preliminarily verified to ensure they comply with relevant design specifications.

[0049] Based on the biomimetic resilient tunnel structure, the physical and mechanical parameters of the variable stiffness material rubber play a key control role in the internal force distribution and deformation response of the biomimetic resilient tunnel structure. A multi-objective optimization algorithm, including a genetic algorithm, was used to optimize the design parameters of the rubber deformation buffer layer 2 in the muscle deformation coordination layer and the rubber buffer pad 42 of the displacement traction joint 4, taking into account multiple design load levels. Key physical and mechanical parameters such as the material's elastic modulus and shear modulus were considered as optimization variables. With performance balance under multiple load levels as the core, a safety and functionality objective function for tunnel operation was constructed. Through parametric finite element numerical simulation, the internal forces and deformation of the tunnel segment 3 under the displacement traction joint 4 with different compressive stiffness, shear stiffness, and rotational stiffness were obtained, establishing an optimization model for the deformation response and internal force distribution of the tunnel segment. By taking the structural internal force response of tunnel segment 3 and the relative rotation angle and displacement deformation of adjacent segments 3 as the objective functions of safety and functionality, and considering the maximum allowable displacement and the maximum design strength of rubber material as constraints, the constrained multi-objective optimization model is further solved to obtain the optimal control solution of tunnel structural deformation and internal force distribution under strong earthquake and dislocation coupling action that meets the design specifications. Based on this, the key physical and mechanical parameters such as elastic modulus, shear modulus, and equivalent damping ratio of rubber deformation buffer layer 2 in the muscle deformation coordination layer and rubber buffer pad 42 in displacement traction joint 4 are determined.

[0050] The processing steps of a multi-objective optimization algorithm include: The internal forces and deformations of the socket-assembled concrete pipe section 3 under the displacement traction joint 4 with different compressive stiffness, shear stiffness, and rotational stiffness were obtained through parametric finite element numerical simulation of the biomimetic tough tunnel structure. An optimization model of the deformation response and internal force distribution of the tunnel pipe section was established. The optimization model uses the structural internal force response of the socket-assembled concrete pipe section 3 and the relative rotation angle and displacement deformation of two adjacent socket-assembled concrete pipe sections 3 as objective functions considering safety and functionality; and uses the maximum allowable displacement and the maximum design strength of the rubber material as constraints. contain The functional objective function Q and the safety objective function P of each pipe segment are defined as follows: in Used to describe the Segment angular deformation, i.e., deformation of a single tunnel segment. To describe the first and The deflection difference between adjacent pipe sections, i.e. the relative geometry of neighboring pipe sections.

[0051] in, and Indicates the location along the tunnel. Bending moment and shear force at the section along the entire length.

[0052] The optimization model is solved to obtain the optimal control solution for the deformation and internal force distribution of the tunnel structure under strong earthquake and dislocation coupling, which conforms to the design specifications. This allows the determination of the elastic modulus, shear modulus and equivalent damping ratio parameters of the rubber deformation buffer layer 2 and the rubber buffer pad 42.

[0053] Ultimately, the optimal design parameters for the biomimetic resilient tunnel were obtained.

[0054] S3. During the construction phase, the lining and support structure of the biomimetic resilient tunnel can be constructed using the mining method or the shield tunneling method. The following will describe the main construction process using the mining method to construct a biomimetic resilient tunnel structure with a design diameter of 10m and a segmented pouring spacing of 8m as an example.

[0055] The scale-like mechanical protective layer consists of the initial lining 1 and the variable stiffness induction ring 5, constructed using the cast-in-place method. The initial lining 1 is made of cast-in-place C50 concrete, 30cm thick, with a construction area of ​​470-500cm radius and segmented pouring intervals of 8m. The initial lining 1 is constructed immediately after the tunnel cross-section is excavated, using a combination of wet spraying and grouting techniques to ensure concrete density. A groove (60cm wide and 30cm deep) for the installation of the variable stiffness induction ring 5 is reserved at the midpoint (4m) of each segment of the initial lining. Interface treatment is performed after 28 days of curing of the initial lining. The variable stiffness induction ring 5 is made of high-damping rubber material, cast using a pressure injection method, 30cm thick and 60cm wide, and arranged parallel to the initial lining. During construction, the reserved groove is cleaned and an interface adhesive is applied. After the concrete and rubber material bond together, curing is performed for 7 days to form an integral, longitudinally extending scale-like mechanical protective layer.

[0056] The muscle deformation coordination layer consists of a 15cm thick rubber deformation buffer layer 2 that runs through the entire tunnel, with a coverage area of ​​455-470cm in radius. Prefabricated rubber rolls are installed using a waterproof membrane trolley. During installation, the rolls are positioned and unfolded, and the joints are welded using a hot-melt welding process to ensure waterproofing. After construction, the tightness between layers is checked to avoid wrinkles or air pockets, ultimately forming the muscle deformation coordination layer.

[0057] The vertebral segmental bearing layer includes socket-assembled concrete pipe sections 3 and displacement coupling joints 4. Displacement coupling joints 4 consist of socket components 41 and rubber buffer pads 42. The pipe sections are made of C50 precast or cast-in-place concrete, with a thickness of 35cm, a construction radius of 420~455cm, and a segment spacing of 8m. The socket-assembled concrete pipe section 3 and socket components 41 are integrally formed. During factory prefabrication, pipe sections 3 and socket components 41 are transported to the site and hoisted into place. They are assembled using socket connections, inserting the shear key of the first pipe section into the groove at the tail of the second section. During cast-in-place construction, formwork support is used to ensure the accuracy of the shear key and groove of the socket component 41. During construction, rubber buffer pads 42 are installed at the notches between the sockets. Low-modulus pads are used in the area near the fault core. Lubricant is applied to the sliding surfaces to allow relative displacement, and the joint stiffness is adjusted according to the design threshold to ensure zoned isolation function during major earthquakes.

[0058] As shown in Figure 9(a), under normal conditions, there is an axial displacement space between two adjacent socket-assembled concrete pipe sections 3; as shown in Figure 9(b), under tension, the axial displacement space between two adjacent socket-assembled concrete pipe sections 3 increases due to the elasticity provided by the scale mechanical protective layer and the muscle deformation coordination layer; as shown in Figure 9(c), under compression, both the scale mechanical protective layer and the muscle deformation coordination layer contract, and the rubber buffer pad in the spine segment bearing layer contracts under pressure, causing the axial displacement space to gradually decrease; as shown in Figure 9(d), under the action of shear forces in both the upper and lower directions, it is supported by the muscle deformation coordination layer, the socket-assembled concrete pipe section 3, and the socket member 41; as shown in Figure 9(e), under the action of bending force in one direction, one end of the axial displacement space between two adjacent socket-assembled concrete pipe sections 3 gradually shrinks.

[0059] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A biomimetic tough tunnel structure combining variable stiffness and graded coordinated deformation, characterized in that, The structure includes a scale-like mechanical protective layer, a muscle deformation coordination layer, and a spine segment bearing layer arranged sequentially from the outside to the inside. The scale-like mechanical protective layer includes a variable stiffness induction ring (5) and a primary liner (1) arranged alternately in the extension direction of the biomimetic tough tunnel structure. The muscle deformation coordination layer is a rubber deformation buffer layer (2). The spine segment bearing layer is a multi-segment structure, each segment including a socket-assembled concrete pipe section (3) and a displacement traction connector (4). The displacement traction connector (4) includes a socket component (41) and a rubber buffer pad (42). The socket-assembled concrete pipe section (3) and the socket component (41) are integrally formed to form the shear key of the previous socket-assembled concrete pipe section (3) and the groove at the tail of the next socket-assembled concrete pipe section (3). The rubber buffer pad (42) is installed in the groove and leaves an axial displacement space between two adjacent socket-assembled concrete pipe sections (3).

2. The biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, The elastic modulus and shear modulus of the rubber buffer pad (42) are distributed along the longitudinal gradient of the tunnel. The elastic modulus and shear modulus are smaller at the socket-assembled concrete pipe section (3) near the active fracture area, and larger at the socket-assembled concrete pipe section (3) far away from the active fracture area.

3. The biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, The contact surfaces of the shear key and the groove at the tail of the subsequent socket-type concrete pipe section (3) are coated with lubricant to form a sliding surface.

4. The biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, The rubber cushioning pad (42) covers the bottom surface, the two opposite sides and the inner side of the groove.

5. A biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, The variable stiffness induction ring (5) is a rubber vibration isolation pad used to form a stiffness abrupt change region, thereby producing an induction effect.

6. The biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, The initial lining (1) is a concrete structure and is a multi-section structure. The variable stiffness induction ring (5) is installed between two adjacent sections of the initial lining (1) through a caulking process, so that relative deformation can occur between different sections of the initial lining (1).

7. A biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, The muscle deformation coordination layer runs through the entire biomimetic toughness tunnel structure.

8. A biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, Under small earthquakes and small displacements, the biomimetic tough tunnel structure works in conjunction with the scale mechanical protective layer and the muscle deformation coordination layer. The scale mechanical protective layer, with its combination of rigidity and flexibility, causes relative deformation between different segments of the initial lining (1), absorbing vibration and deformation. The muscle deformation coordination layer, with its high synergy and high toughness, further absorbs and disperses vibration and deformation.

9. A biomimetic tough tunnel structure with variable stiffness and graded coordinated deformation as described in claim 1, characterized in that, Under the condition of a large earthquake and displacement, the biomimetic resilient tunnel structure induces the displacement of the core area of ​​the tunnel by the scale mechanical protective layer; the displacement is transmitted to the adjacent socket-assembled concrete pipe section (3) by the spine segment bearing layer through the displacement traction joint (4), forming a traction cross line in the core area of ​​the tunnel.

10. A design method for a biomimetic resilient tunnel structure with variable stiffness and graded coordinated deformation as described in any one of claims 1-9, characterized in that, include: A multi-objective optimization algorithm is used for structural parameter design. The processing steps of the multi-objective optimization algorithm include: The internal forces and deformation of the socket-assembled concrete pipe sections (3) under the displacement traction joint (4) with different compression stiffness, shear stiffness and rotation stiffness were obtained by parametric finite element numerical simulation of the biomimetic tough tunnel structure. An optimization model of the deformation response and internal force distribution of the tunnel pipe sections was established. The optimization model takes the structural internal force response of the socket-assembled concrete pipe section (3) and the relative rotation angle and displacement deformation of two adjacent socket-assembled concrete pipe sections (3) as the objective functions considering safety and functionality; and takes the maximum allowable displacement and the maximum design strength of the rubber material as the constraints. The calculation expressions for the security and functionality objective functions, including the functionality objective function Q and the security objective function P, are as follows: In the formula, For the first Deformation of pipe section angle, For the first and The difference in deflection between adjacent pipe sections The number of socket-assembled concrete pipe sections; In the formula, and These represent the bending moment and shear force at the cross-sections along the tunnel route, respectively. The optimization model is solved to obtain the optimal control solution for the deformation and internal force distribution of the tunnel structure under strong earthquake and dislocation coupling, which conforms to the design specifications, thereby determining the elastic modulus, shear modulus and equivalent damping ratio parameters of the rubber deformation buffer layer (2) and the rubber buffer pad (42).

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