Intelligent compensation method and system for frost heaving force of high-altitude frozen soil variable cross-section tunnel based on cloud-edge collaborative structure health monitoring

Abstract

The invention discloses an intelligent compensation method and system for the frost heaving force of a high-altitude frozen soil variable cross-section tunnel based on cloud-edge collaborative structure health monitoring, belongs to the technical field of structure health monitoring and intelligent monitoring control, and is particularly applied to cold region tunnel engineering. A variable cross-section compensation section is arranged in a frost heaving high-risk area, an annular buffer cavity is formed between a secondary lining and a primary support, a phase change energy absorption layer is arranged on a vault, a shape memory alloy elastic layer is arranged at an arch bottom, and frost heaving energy is guided and absorbed in cooperation with an annular drainage and heat preservation waterproof structure. The intelligent monitoring nodes are arranged along the tunnel to collect pressure, displacement and temperature data, and the energy management control unit regulates and controls the phase change layer, the elastic layer and the temperature control device in a linkage mode according to a preset safety threshold value and a grading rule and can adaptively correct the threshold value according to multi-cycle operation data. According to the method, the frost heaving peak pressure and cyclic residual deformation borne by the secondary lining are remarkably reduced, and the safety and durability of the high-altitude frozen soil tunnel are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of structural health monitoring and industrial internet control, and is particularly applied to cold region tunnel engineering, and particularly relates to a high-altitude frozen soil variable cross-section tunnel frost heaving force intelligent compensation method and system based on cloud-edge collaborative structural health monitoring. BACKGROUND

[0002] When a tunnel is built in a high-altitude permafrost region, the pore water of surrounding rock freezes and expands in volume under the combined influence of seasonal freezing and thawing cycles and permafrost degradation, forming a frost heaving force acting on the lining structure. If only the conventional secondary lining or simple thermal insulation, waterproofing and drainage measures are adopted, when the extreme climate or local geological conditions change, the frost heaving force may still cause the secondary lining to crack, the arch to bulge, the track bed to arch and the residual deformation to accumulate after the freeze-thaw cycle, which may seriously endanger the safety of the tunnel structure and driving and significantly increase the maintenance and reinforcement costs.

[0003] Existing engineering practices mainly adopt two types of coping ideas: one type focuses on passive enhancement, which improves the bearing capacity and deformation tolerance of the structure by thickening the lining, setting a sliding layer or using high-strength and high-toughness materials; the other type focuses on environmental regulation, which improves the temperature field and water content of the surrounding rock by using thermal insulation, drainage systems and ground temperature control measures to weaken the development of frost heaving. These two types of measures can alleviate the frost heaving disease to some extent, but generally have the following problems: first, the monitoring means are mostly a small number of discrete measuring points, lacking real-time sensing capability of multiple parameters such as pressure, displacement and temperature for the whole line, making it difficult to identify local high-risk areas in time; second, the monitoring system usually operates independently, only providing over-limit alarm or post-analysis, and has not yet formed a closed loop with industrial control systems, execution structures and operation and maintenance decisions, and lacks long-term self-adaptive optimization based on cloud-edge collaboration and digital models; third, the variable cross-section lining, buffer cavity and other structural measures are often designed separately from the monitoring and control system, lacking a mechanism for dynamically scheduling the frost heaving energy path according to the monitoring data, resulting in limited linkage between the structural measures and the digital monitoring and control. SUMMARY

[0004] Technical purpose: In view of the deficiencies of the prior art, the present application discloses a high-altitude frozen soil variable cross-section tunnel frost heaving force intelligent compensation method and system based on cloud-edge collaborative structural health monitoring, which can realize real-time sensing, shunting absorption and reversible compensation of the frost heaving energy under the condition of limited lining thickness, and adaptively adjust the safety threshold and control strategy in the whole life cycle through intelligent monitoring and cloud-edge collaborative control, so as to reduce the frost heaving peak pressure on the secondary lining and the residual deformation after the freeze-thaw cycle.

[0005] Technical scheme: In order to achieve the above technical purpose, the present application adopts the following technical scheme:

[0006] The application discloses a high-altitude frozen soil variable cross-section tunnel frost heaving force intelligent compensation method based on cloud edge collaborative structure health monitoring.

[0007] Based on the ground temperature, lithology and water content survey data, a high-risk area of frost heaving is identified, the tunnel is divided into a variable cross-section compensation section, a conventional section and a transition section arranged between the two, a continuous annular buffer cavity is formed along the circumferential direction of the tunnel between the secondary lining outside and the primary support in the variable cross-section compensation section, a phase change energy absorption layer is arranged at the vault of the annular buffer cavity, a shape memory alloy elastic layer is arranged at the arch bottom of the annular buffer cavity, and a ring-shaped drainage assembly is arranged at the two side arch feet, and a heat preservation and waterproof layer is arranged outside the annular buffer cavity.

[0008] A plurality of intelligent monitoring nodes are arranged along the tunnel, each intelligent monitoring node comprises a pressure sensor, a displacement sensor and a temperature sensor, and a local microcontroller for pre-processing and abnormality identification of multi-parameter monitoring data, and each intelligent monitoring node is connected to an energy management control unit through wired or wireless mode, so as to form an edge monitoring network of the tunnel frost heaving state.

[0009] The energy management control unit calculates a safe equivalent external pressure threshold value that can be borne based on the secondary lining concrete compressive strength design value, the equivalent thickness of the secondary lining and the secondary lining inner radius, and determines a displacement threshold value and a temperature threshold value in combination with the allowable convergence of the tunnel and the temperature limit value at the key position, at least one of the equivalent external pressure threshold value, the displacement threshold value and the temperature threshold value is set as a main control threshold value, and the remaining threshold values are set as parallel constraint threshold values.

[0010] During the tunnel operation, the energy management control unit continuously receives the pressure, displacement and temperature data uploaded by each intelligent monitoring node, calculates the current equivalent external pressure and compares it with the main control threshold value, issues a warning when the monitoring value reaches 90% of the main control threshold value, starts the linkage regulation when the monitoring value reaches the main control threshold value, and removes the linkage regulation when the monitoring value falls to 70% of the main control threshold value and the duration is not less than the set hysteresis time.

[0011] During the linkage regulation, the energy management control unit cooperatively controls the working state of the phase change energy absorption layer, the pre-tightening or heating state of the shape memory alloy elastic layer and the heating or cooling device arranged around the annular buffer cavity according to the current frost heaving state and the historical operation data, so that the frost heaving energy is preferentially absorbed by the phase change energy absorption layer, the remaining energy is released through elastic displacement and water-heat boundary adjustment, thereby reducing the equivalent frost heaving force transmitted to the secondary lining and inhibiting the residual deformation after the freeze-thaw cycle.

[0012] After each complete freezing-thawing cycle, the energy management control unit archives the peak equivalent external pressure, the peak convergence amount, the lowest temperature, and the corresponding control behavior and control effect in the cycle, and updates the reduction coefficients of the safety equivalent external pressure threshold value, the displacement threshold value, and the temperature threshold value based on the monitoring and control records of multiple freezing-thawing cycles, and applies the update results to subsequent operation cycles to realize adaptive optimization of the safety threshold values and the control strategies in the whole life cycle.

[0013] Preferably, the transition section continuously and gradually changes the cross-sectional parameters in the tunnel axial direction, and the cross-sectional parameters at least include two of the radial thickness of the annular buffer cavity, the unit surface heat capacity or surface density of the phase change energy absorption layer, and the arrangement pitch of the shape memory alloy elastic layer in the ring direction; the radial thickness of the annular buffer cavity is 0.10m-0.40m, the length of a single variable cross-section compensation section is 5m-20m, the distance between the center lines of adjacent variable cross-section compensation sections is 50m-200m, and the length of the transition section is 1m-3m.

[0014] Preferably, the local microcontroller of the intelligent monitoring node is configured to filter, count, and feature extract the raw data of pressure, displacement, and temperature to form feature data including the frost heave rate, the temperature change rate, and the convergence rate, and to perform anomaly identification on the feature data and upload only the feature data and anomaly markers to the energy management control unit.

[0015] Preferably, the energy management control unit includes an edge control module and a cloud collaborative module, the edge control module is used to perform online monitoring, equivalent external pressure calculation, and hierarchical trigger control, and the cloud collaborative module is used to receive historical monitoring data and control records of multiple freezing-thawing cycles, build a digital model of the tunnel-surrounding rock-annular buffer cavity, update the frost heave energy prediction parameters and the reduction coefficients of the safety equivalent external pressure threshold value, the displacement threshold value, and the temperature threshold value, and issue the update results to the edge control module.

[0016] Preferably, when the displacement threshold value reaches first, the energy management control unit preferentially adjusts the pre-tightening or heating state of the shape memory alloy elastic layer to increase the displacement and promote the structure to rebound; when the temperature threshold value reaches first, the energy management control unit preferentially adjusts the heating or cooling device around the annular buffer cavity to change the freezing front position and reduce the cold input; when the equivalent external pressure threshold value reaches first, the phase change energy absorption layer, the shape memory alloy elastic layer, and the heating or cooling device are cooperatively executed in a preset proportion.

[0017] Preferably, the variable cross-section compensation section, the transition section and the conventional section are arranged alternately along the longitudinal direction of the tunnel, the variable cross-section compensation section in the high frost heave risk area is arranged at a higher density than that in the low frost heave risk area, and the length of the variable cross-section compensation section and the distance between adjacent variable cross-section compensation sections are adjusted in different zones according to the evaluation results of the energy management control unit on the frost heave energy and control effect of each section.

[0018] A high-altitude frozen soil variable cross-section tunnel frost heave force intelligent compensation system based on cloud-edge collaborative structural health monitoring, used to implement a high-altitude frozen soil variable cross-section tunnel frost heave force intelligent compensation method based on cloud-edge collaborative structural health monitoring, comprising:

[0019] A tunnel lining structure subsystem is used to form a variable cross-section compensation section distributed along the longitudinal direction of the tunnel and a transition section arranged between the variable cross-section compensation section and the conventional section, an annular buffer cavity is arranged between the secondary lining outside of the variable cross-section compensation section and the primary support, a phase change energy absorption layer is arranged at the vault of the annular buffer cavity, a shape memory alloy elastic layer is arranged at the arch bottom of the annular buffer cavity, a ring-shaped drainage assembly is arranged at the two side arch feet, and a heat preservation and waterproof layer is arranged outside the annular buffer cavity.

[0020] A monitoring subsystem comprises a plurality of intelligent monitoring nodes arranged at different positions of the tunnel, each intelligent monitoring node comprising a pressure sensor, a displacement sensor and a temperature sensor, and a local microcontroller for pre-processing and abnormality recognition of monitoring data, and each intelligent monitoring node is connected to the energy management control unit through wired or wireless means.

[0021] An energy management control unit comprises an edge control module and a cloud collaborative module, the edge control module is connected to the monitoring subsystem and is used to receive the pressure, displacement and temperature data uploaded by the intelligent monitoring nodes, calculate the equivalent external pressure, and generate control instructions for the phase change energy absorption layer, the shape memory alloy elastic layer and the heating or cooling device according to the pre-set safety equivalent external pressure threshold, displacement threshold and temperature threshold, and the cloud collaborative module is used to receive historical monitoring data and control records through a communication interface, build a digital model of the tunnel-surrounding rock-annular buffer cavity, update the thresholds, and issue the updated threshold parameters to the edge control module.

[0022] An execution subsystem comprises a temperature control execution mechanism connected to the phase change energy absorption layer, a mechanical execution mechanism connected to the shape memory alloy elastic layer, and a heating or cooling device arranged around the annular buffer cavity, and the execution subsystem is connected to the energy management control unit and is used to receive the control instructions and perform linkage control on the phase change energy absorption layer, the shape memory alloy elastic layer and the heating or cooling device.

[0023] Preferably, the local microcontroller of the intelligent monitoring node is configured to filter, statistically analyze, and extract features from the raw data of pressure, displacement, and temperature to form feature data including frost heave rate, temperature change rate, and convergence rate, and to identify anomalies in the feature data and upload the feature data and anomaly markers to the edge control module.

[0024] Preferably, the edge control module is configured to generate an early warning message when a certain monitored quantity reaches 90% of the corresponding safety threshold, generate a linkage control command when the monitored quantity reaches the safety threshold, and generate a release control command when the monitored quantity falls back to 70% of the safety threshold and the duration is not less than a set hysteresis time; the cloud collaboration module is configured to adjust the reduction coefficient of the safety threshold according to the peak value of the monitored quantity, control behavior and control effect of the current cycle after each freeze-thaw cycle, and send the adjustment result to the edge control module.

[0025] Preferably, the cross-sectional parameters of the transition section in the tunnel axis are continuously and gradually changed. The cross-sectional parameters include at least two of the following: the radial thickness of the annular buffer cavity, the unit surface heat capacity or surface density of the phase change energy absorption layer, and the circumferential arrangement pitch of the shape memory alloy elastic layer, thereby forming a smooth transition of stiffness and temperature field between the variable cross-section compensation section and the conventional lining section.

[0026] Beneficial Effects: The intelligent compensation method and system for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring provided by this invention has the following beneficial effects:

[0027] 1. This invention introduces intelligent monitoring nodes and energy management control units to build a multi-parameter edge monitoring network along the tunnel, which can acquire pressure, displacement and temperature information in real time. Based on multi-index safety thresholds and graded triggering rules, it can control the phase change layer, elastic layer and temperature control device as needed, so as to realize the active scheduling and allocation of frost heave energy path and improve the timeliness and pertinence of control.

[0028] 2. This invention sets up an edge control module and a cloud collaboration module in the energy management control unit, uses multi-cycle operation data to build a digital model and adaptively updates the safety threshold reduction coefficient, so that the control strategy can dynamically evolve with permafrost degradation, climate change and operation experience, maintain a reasonable safety margin and material utilization efficiency in long-term operation, and has obvious long-term adaptability and economy.

[0029] 3. This invention establishes a synergistic system of latent heat absorption, elastic yielding, and rebound by setting an annular buffer cavity in the variable cross-section compensation section, arranging a phase change energy absorption layer at the top of the arch, and arranging a shape memory alloy elastic layer at the bottom of the arch. This system delays the release of frost heave energy during the freezing process and diverts it to a controllable buffer zone in space, significantly reducing the equivalent frost heave force transmitted to the secondary lining and reducing residual deformation after freeze-thaw cycles. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0031] Figure 1 This is a flowchart of the intelligent compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in this invention.

[0032] Figure 2 This is a schematic diagram of the cross-section of the variable cross-section compensation section of the present invention;

[0033] Figure 3 This is a schematic diagram of the annular buffer cavity layers and functional partitions of the present invention;

[0034] Figure 4 This is a schematic diagram of the phase change energy absorption layer structure of the present invention;

[0035] Figure 5 For monitoring—energy management control function block diagram;

[0036] Figure 6 This is a schematic diagram showing the longitudinal arrangement of the variable cross-section compensation section and the transition section along the tunnel.

[0037] Figure 7 This is a functional block diagram of an intelligent compensation system for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring.

[0038] In the diagram: 11. Variable cross-section compensation section; 12. Transition section; 21. Surrounding rock; 31. Annular buffer cavity; 41. Phase change energy absorption layer; 42. Shape memory alloy elastic layer; 5. Secondary lining; 51. Intelligent monitoring node; 52. Energy management control unit; 61. Circumferential drainage assembly; 62. Thermal insulation and waterproof layer; 71. Inspection window; 72. Positioning ring; 73. Fixture; 74. Cable / sensor harness; 75. Heating / cooling component. Detailed Implementation

[0039] The present invention will now be described more clearly and completely by way of a preferred embodiment in conjunction with the accompanying drawings, but this does not limit the invention to the scope of the described embodiment.

[0040] like Figure 1As shown, a smart compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring specifically includes the following steps:

[0041] S1. Based on geothermal, lithology and water content survey data, identify high-risk areas for frost heave, divide the tunnel into a variable cross-section compensation section, a conventional section and a transition section between the two, form a continuous annular buffer cavity along the tunnel circumference between the outer side of the secondary lining and the initial support of the variable cross-section compensation section, arrange a phase change energy absorption layer on the arch top of the annular buffer cavity, arrange a shape memory alloy elastic layer on the arch bottom of the annular buffer cavity, arrange circumferential drainage components on both sides of the arch foot, and set a thermal insulation and waterproof layer on the outside of the annular buffer cavity.

[0042] S2. Multiple intelligent monitoring nodes are deployed along the tunnel. Each intelligent monitoring node includes a pressure sensor, a displacement sensor, and a temperature sensor, as well as a local microcontroller for preprocessing multi-parameter monitoring data and identifying anomalies. Each intelligent monitoring node is connected to the energy management control unit via wired or wireless means to form an edge monitoring network for the tunnel's frost heave state.

[0043] S3. The energy management and control unit calculates the safe equivalent external pressure threshold based on the design value of the compressive strength of the secondary lining concrete, the equivalent thickness of the secondary lining, and the inner radius of the secondary lining. It also determines the displacement threshold and temperature threshold by combining the tunnel's allowable convergence amount and the temperature limit at key locations. At least one of the equivalent external pressure threshold, displacement threshold, and temperature threshold is set as the main control threshold, and the remaining thresholds are set as parallel constraint thresholds.

[0044] S4. During tunnel operation, the energy management control unit continuously receives pressure, displacement and temperature data uploaded by each intelligent monitoring node, calculates the current equivalent external pressure and compares it with the main control threshold. When the monitored quantity reaches 90% of the main control threshold, an early warning is issued. When the monitored quantity reaches the main control threshold, linkage control is initiated. When the monitored quantity falls back to 70% of the main control threshold and the duration is not less than the set hysteresis time, linkage control is deactivated.

[0045] S5. During the linkage control period, the energy management control unit coordinates the working state of the phase change energy absorption layer, the pre-tightening or heating state of the shape memory alloy elastic layer, and the heating or cooling devices arranged around the annular buffer cavity based on the current frost heave state and historical operating data. This ensures that the frost heave energy is preferentially absorbed by the phase change energy absorption layer, and the remaining energy is released through elastic clearance and hydrothermal boundary adjustment, thereby reducing the equivalent frost heave force transmitted to the secondary lining and suppressing residual deformation after freeze-thaw cycles.

[0046] S6. After each complete freeze-thaw cycle, the energy management control unit records and archives the peak value of the equivalent external pressure, the peak value of the convergence, the minimum temperature, and the corresponding control behavior and control effect within that cycle. Based on the monitoring and control records of multiple freeze-thaw cycles, the reduction coefficients of the safety equivalent external pressure threshold, displacement threshold, and temperature threshold are updated, and the updated results are applied to subsequent operating cycles to achieve adaptive optimization of the safety threshold and control strategy throughout the entire life cycle.

[0047] like Figure 7 As shown, an intelligent compensation system for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring is used to implement the intelligent compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring as described above, including:

[0048] The tunnel lining structure subsystem is used to form variable cross-section compensation sections distributed along the longitudinal direction of the tunnel and transition sections set between the variable cross-section compensation sections and the conventional sections. An annular buffer cavity is set between the outer side of the secondary lining of the variable cross-section compensation section and the initial support. A phase change energy absorption layer is arranged on the arch top of the annular buffer cavity, a shape memory alloy elastic layer is arranged on the arch bottom of the annular buffer cavity, circumferential drainage components are set on both arch feet, and a thermal insulation and waterproof layer is set on the outer side of the annular buffer cavity.

[0049] The monitoring subsystem includes multiple intelligent monitoring nodes deployed at different locations in the tunnel. Each intelligent monitoring node includes a pressure sensor, a displacement sensor, and a temperature sensor, as well as a local microcontroller for preprocessing monitoring data and identifying anomalies. Each intelligent monitoring node is connected to the energy management control unit via wired or wireless means.

[0050] The energy management and control unit includes an edge control module and a cloud collaboration module. The edge control module is connected to the monitoring subsystem and is used to receive pressure, displacement, and temperature data uploaded by intelligent monitoring nodes, calculate the equivalent external pressure, and generate control commands for the phase change energy absorption layer, shape memory alloy elastic layer, and heating or cooling devices according to the pre-set safe equivalent external pressure threshold, displacement threshold, and temperature threshold and the hierarchical control rules. The cloud collaboration module is used to receive historical monitoring data and control records through the communication interface, construct a digital model of the tunnel-surrounding rock-annular buffer cavity, update the thresholds, and send the updated threshold parameters to the edge control module.

[0051] The execution subsystem includes a temperature control actuator connected to the phase change energy absorption layer, a mechanical actuator connected to the shape memory alloy elastic layer, and a heating or cooling device arranged around the annular buffer cavity. The execution subsystem is connected to the energy management control unit to receive control commands and perform linkage control on the phase change energy absorption layer, the shape memory alloy elastic layer, and the heating or cooling device.

[0052] Example 1

[0053] In high-altitude permafrost tunnels, the tunnel is divided into several high-risk and relatively low-risk frost heave zones along its longitudinal direction based on ground temperature, lithology, and water content. A variable cross-section compensation section 11 is arranged in the high-risk frost heave zone. Within the range of the variable cross-section compensation section 11, an annular buffer cavity 31 is reserved between the secondary lining 5 and the initial support 4.

[0054] like Figure 2 The diagram shows a cross-sectional view of the variable cross-section compensation section, illustrating its functional hierarchy and relative positional relationships across the cross-section. 21 represents the outer boundary environment of the surrounding rock / soil layer; 5 represents the secondary lining, which is the main structure responsible for load-bearing and deformation control. The annular buffer cavity 31 formed between the outer side of the secondary lining 5 and the initial support (its circumferential continuity is indicated by a cross-sectional line in the diagram) serves as the energy buffer and deformation adjustment space for this invention.

[0055] The radial thickness of the annular buffer cavity 31 is selected within the range of 0.10m-0.40m, determined by combining the estimated frost heave energy and the heat absorption capacity per unit volume of the phase change material; the length Lseg of a single variable cross-section compensation section 11 is 5m-20m, and the centerline spacing L1 between adjacent compensation sections 11 is 50m-200m; the length L2 of the conventional section is coordinated with L1 to meet the overall line layout requirements. A transition section 12 is set between the variable cross-section compensation section 11 and the conventional section, and the length Ltr of the transition section is 1m-3m.

[0056] A phase change energy absorption layer 41 (shown as a light gray strip in the figure) is arranged at the arched position of the annular buffer cavity 31. The phase change energy absorption layer adopts the form of microcapsule phase change material sandwich, with the phase change temperature range matching the local active freezing temperature range of the permafrost. The latent heat value matches the designed heat absorption capacity per unit volume. The microcapsule particle size is controlled between 0.20mm and 1.00mm to balance heat transfer efficiency and mechanical properties. A shape memory alloy elastic layer 42 (shown as an equally spaced small circular array in the figure) is arranged at the arched bottom position of the annular buffer cavity 31. The shape memory alloy elastic layer adopts the form of a nickel-titanium alloy helical spring array with a wire diameter of 5mm to 10mm, an effective spring length of 0.20m to 0.50m, and a circumferential spacing of 0.20m to 0.40m. This allows the spring to provide high equivalent stiffness and energy dissipation capacity under low temperature conditions and release elastic energy during rewarming, ensuring the self-resetting of structural rebound and residual deformation.

[0057] The circumferential drainage component 61 is located at the arch feet on both sides (slender rectangles in the figure), responsible for collecting and guiding seepage water around the buffer cavity, reducing the amplification effect of moisture content fluctuations on the freeze-thaw cycle. The circumferential drainage component 61 consists of seepage pipes, water collection blind ditches, and longitudinal drainage ditches arranged along the arch feet. The seepage pipes have a diameter of 30mm to 50mm and form a drainage channel with the lower edge of the annular buffer cavity 31, introducing seepage water and meltwater into the longitudinal drainage system to reduce moisture content fluctuations. The thermal insulation and waterproof layer 62 covers the outside and consists of a closed-cell rigid insulation board and a waterproof membrane. The insulation board is not less than 30mm thick, and the waterproof membrane forms a stable and continuous waterproof interface with the initial support, inhibiting the adverse effects of external water intrusion and temperature changes on the synergistic mechanism of the annular buffer cavity 31, the phase change energy absorption layer 41, and the shape memory alloy elastic layer 42. In summary, this figure intuitively illustrates the continuous path of load-bearing, buffering, heat absorption and peak reduction, elastic yielding / rebound, drainage, and thermal insulation and waterproofing.

[0058] In terms of assembly, the geometric gap between the annular buffer cavity 31 and the lining 5 is determined according to the design. The phase change energy absorption layer 41 and the shape memory alloy elastic layer 42 are respectively fixed to their preset mounting positions at the top and bottom, through positioning and fastening components (see details). Figure 4 The positioning ring 72 and the fixing element 73 in the middle maintain circumferential uniformity and maintainability.

[0059] like Figure 3 As shown in the figure, this enlarged view illustrates the hierarchical structure of the secondary lining 5 and the annular buffer cavity 31, clearly defining the relative geometric relationships between the phase change energy absorption layer 41, the shape memory alloy elastic layer 42, the circumferential drainage component 61, the thermal insulation and waterproofing layer 62, and the lining. The figure shows the inner contour of the secondary lining, with the annular buffer cavity 31 marked by cross-sectional lines on its outer side. The phase change energy absorption layer 41 is embedded in the upper edge of the annular buffer cavity 31, appearing as a continuous or segmented sandwich / panel structure; the shape memory alloy elastic layer 42 is arranged at the lower edge of the annular buffer cavity 31, illustrated as a row of circumferential nodes in the figure, but in practice, multiple rows or continuous arrays can be formed according to the design to meet the requirements of different frost heave levels for equivalent stiffness and energy dissipation. This hierarchical structure achieves functional layering of load-bearing, buffering, energy absorption, clearance, repositioning, drainage, and thermal insulation.

[0060] At the arched foot positions on both sides, the circumferential drainage component 61 and the lower edge of the annular buffer cavity 31 form a drainage channel, which, together with the complete coverage interface of the outer thermal insulation and waterproof layer 62, constitutes a composite boundary of drainage and isolation. A sealing node is provided at the connection between the edge of the phase change energy absorption layer 41 and the thermal insulation and waterproof layer 62 to prevent external water-heat disturbances to the working cavity of the phase change material; the end of 42 is connected to the substrate through positioning and fastening elements to ensure convenient force transmission and replacement (see assembly details for this part). Figure 4As can be clearly seen from this diagram: the top is a phase change energy absorption layer, the bottom is a shape memory alloy elastic layer, the sides are thermal insulation and waterproof layers, and the arched feet are drainage channels, all of which together form a layered coupled force-temperature control system around the annular buffer cavity.

[0061] like Figure 4 As shown in the figure, this diagram illustrates the modular components installed within the annular buffer cavity 31 and their assembly sequence, facilitating understanding of the installation, maintenance, and replacement process. From the inside out or from top to bottom, the components are as follows: Phase change energy absorption layer 41 (panel / sandwich component) for latent heat absorption and temperature field regulation; Shape memory alloy elastic layer 42 (circumferential spring array) for providing reversible elasticity, hysteresis energy dissipation, and reset capability; Positioning ring 72 for limiting the circumferential and axial positions of the phase change energy absorption layer 41 and the shape memory alloy elastic layer 42, ensuring uniform working gap and force distribution; Fixing component 73 for reliably connecting the module to the structural substrate, meeting the requirements for long-term stability under seismic and freeze-thaw cycles.

[0062] The inspection window 71 is located in an easily accessible position and uses a sealed cover structure. When opened, it allows direct access to the phase change energy absorption layer 41, the shape memory alloy elastic layer 42, and the heating / cooling component 75, facilitating replacement of the phase change energy absorption layer, adjustment of pre-tightening, or condition checks. The heating / cooling component 75 acts as an actuator, linked with the energy management control unit 52, to guide the temperature of the phase change energy absorption layer 41 and implement a pre-tightening strategy for the shape memory alloy elastic layer 42. The cable / sensor harness 74 provides signal and power channels for the monitoring component 51 and the energy management control unit 52. This diagram clearly shows the spatial order and connection relationship of each component: the positioning ring and the fixing component form the assembly "skeleton," the phase change energy absorption layer 41 and the shape memory alloy elastic layer 42 are the core energy units, and the inspection window 71, cable / sensor harness 74, and heating / cooling component 75 form the inspection and control interface, ultimately forming a modular unit integrating heat, force, control, and maintenance within the annular buffer cavity 31.

[0063] like Figure 6 The diagram shows the longitudinal arrangement of the variable cross-section compensation section and transition section along the tunnel. From left to right along the baseline, a repeating sequence of "conventional section → transition section → compensation section → conventional section → transition section → compensation section" is displayed. The conventional section is represented by a blank rectangle, transition section 12 by a diagonally cross-sectional rectangle, and variable cross-section compensation section 11 by a solid gray rectangle. This diagram aims to visually illustrate the overall approach of this invention—achieving risk zoning management and optimized material allocation through segment combinations in the longitudinal direction.

[0064] The transition section 12 is positioned between the conventional section and the variable cross-section compensation section 11 to achieve a smooth transition in geometry and stiffness in the longitudinal direction, avoiding stress concentration at the interface and abrupt changes in temperature and moisture content caused by sudden changes in stiffness. The presence of the transition section 12 allows the energy buffering and rebound mechanism inside the variable cross-section compensation section 11 to be naturally connected to the conventional lining section, ensuring the continuity and controllability of the transmission and attenuation of the frost heave effect along the line.

[0065] The variable cross-section compensation section 11 is the core functional section in the longitudinal direction of this invention. Its cross-section includes an annular buffer cavity 31, a phase change energy absorption layer 41, a shape memory alloy elastic layer 42, a circumferential drainage component 61, and a thermal insulation and waterproof layer 62. During the freezing period, the phase change energy absorption layer 41 preferentially absorbs latent heat and reduces peak ice expansion, while the shape memory alloy elastic layer 42 provides reversible elasticity and hysteresis energy dissipation. During the thawing period, the phase change energy absorption layer 41 guides the temperature field to gradually decrease, the shape memory alloy elastic layer 42 releases elastic energy and promotes structural rebound, the circumferential drainage component 61 drains seepage water, and the thermal insulation and waterproof layer 62 suppresses external hydrothermal disturbances, thereby achieving a synergistic path of energy absorption, yielding, resetting, drainage, and insulation. The conventional section is used in low-risk areas to maintain a constant scale and construction method, thereby reducing the amount of engineering work and the total life cycle cost.

[0066] The diagram shows three types of dimension lines used solely to explain the layout logic: First, Lseg, representing the length of a single variable cross-section compensation segment 11 along the line direction, measured at the start and end points of that segment; second, Ltr, representing the length of the transition segment 12, also measured at the start and end points, typically used to accommodate the gradual changes in the thickness of the annular buffer cavity 31, the gradual changes in the unit surface heat capacity (or surface density) of the phase change energy absorption layer 41, and the gradual changes in the circumferential pitch and preload of the shape memory alloy elastic layer 42, ensuring that the first derivatives of stress and temperature fields do not abruptly change within the transition range; third, L1 / L2, representing the distance between the centerlines of two adjacent variable cross-section compensation segments 11, used to control the rhythm of repeated layout and the zoning scale along the line. To emphasize the engineering logic of repeatable layout, the second group of "12→11" on the right is shown as a continuous diagram.

[0067] This diagram is a functional illustration of the layout relationship and is not drawn to scale. Specific dimensions and materials are not limited. The actual values ​​of Lseg, Ltr, and L1 / L2, as well as the zoning strategy, should be determined through calculation and monitoring-control closed-loop verification, taking into account the distribution of frost heave risk, geothermal gradient, water content, surrounding rock type, and operational level. When monitoring shows an increase in risk in a certain section, L1 / L2 can be reduced or Ltr can be appropriately lengthened, and the parameters of the phase change energy absorption layer 41 and the shape memory alloy elastic layer 42 can be adjusted accordingly to enhance local frost heave resistance. When the risk decreases, reverse optimization can be performed to maintain the dynamic optimal balance between safety reserves and material input.

[0068] Within the transition section 12, the radial thickness of the annular buffer cavity 31, the unit surface heat capacity / surface density of the phase change energy absorption layer 41, the circumferential pitch and preload of the shape memory alloy elastic layer 42 are generally adjusted in a predetermined gradient, and optimized synchronously with the node structure of the thermal insulation and waterproof layer 62 and the circumferential drainage component 61, so that the temperature field and stress field change continuously in both the longitudinal and transverse directions, ensuring that no new stress peaks or weak points of water seepage are introduced during the transition from the compensation section 11 to the conventional section.

[0069] Example 2

[0070] like Figure 5 As shown, the present invention deploys a monitoring subsystem and an energy management and control unit 52 along the tunnel to form a monitoring-decision-execution closed loop.

[0071] The monitoring subsystem comprises multiple intelligent monitoring nodes 51, each integrating at least a pressure sensor, a displacement sensor, a temperature sensor, and a local microcontroller. The pressure sensor has a range of 0 MPa to 10 MPa and an accuracy not exceeding ±0.02 MPa; the displacement sensor has a resolution not exceeding 0.1 mm and is used to measure the convergent displacement behind the secondary lining or inside the annular buffer cavity; the temperature sensor has a temperature measurement range of −40℃ to 20℃ and is used to record the temperature of the surrounding rock and the annular buffer cavity. The intelligent monitoring nodes 51 are distributed at key locations such as the arch crown, arch shoulder, and arch foot, both within the variable cross-section compensation section 11 and appropriately placed in the conventional section for comparison and verification.

[0072] The local microcontroller of the intelligent monitoring node 51 is responsible for sensor signal acquisition, noise filtering, statistical analysis and feature extraction. It converts the raw data of pressure, displacement and temperature into feature quantities such as frost heave rate, temperature change rate and convergence rate, and performs anomaly identification, such as identifying sensor failures and sudden data that obviously does not conform to physical laws. It only uploads feature data and anomaly markers to the energy management control unit 52, thereby reducing the communication load and improving the reliability of anomaly detection.

[0073] The energy management control unit 52 includes an edge control module deployed in the tunnel or station and a cloud collaboration module deployed in the data center or cloud platform. The edge control module is connected to the intelligent monitoring node 51 via industrial Ethernet or low-power wireless network, receives characteristic data and anomaly markers from each monitoring point in real time, calculates the equivalent external pressure of the segment, compares it with the safety threshold, and generates control commands according to hierarchical rules.

[0074] Under strength-dominant conditions, the upper limit of the design equivalent external pressure that secondary lining 5 can withstand is... It can be calculated using the following formula:

[0075]

[0076] in, The design value of the compressive strength of the secondary lining concrete (MPa); The equivalent thickness of the secondary lining (m, taking into account the combined effects of cracking and construction joints); The inner radius of the secondary lining (m); It is the geometric-boundary synthesis coefficient (dimensionless, used to calculate eccentricity, non-circularity, and uneven stress); The factor representing the combined reduction due to durability, temperature, and long-term effects (dimensionless).

[0077] To improve the robustness of the equivalent external pressure, this invention preferably employs a multi-source fusion method to calculate the equivalent external pressure. For example, the following formula can be used: in, For the equivalent external pressure after fusion, The average external pressure is directly measured by the pressure sensor. The equivalent external pressure is obtained from the strain or displacement inversion of the secondary lining. External pressures predicted based on short-term historical data, The confidence weights are adaptively updated based on sensor health and historical residuals.

[0078] Temperature and displacement thresholds are determined based on the allowable temperature range and allowable convergence amount during tunnel design. In engineering design, the primary control threshold (pressure, displacement, or temperature) is determined according to specific line conditions, with the other two serving as parallel constraint thresholds. When the monitored quantity reaches 90% of the primary control threshold, the edge control module issues an early warning and records the warning time and location. When the monitored quantity reaches the primary control threshold, the edge control module generates a linkage control command, driving the phase change energy absorption layer 41, shape memory alloy elastic layer 42, and heating or cooling devices into working condition. When the monitored quantity falls back to 70% of the primary control threshold and the duration is not less than the set hysteresis time, the edge control module generates a release control command, gradually restoring each actuator to standby state.

[0079] When different thresholds are reached first, the energy management control unit 52 employs different control strategies: when the displacement threshold is reached before the pressure threshold, the pre-tightening or heating state of the shape memory alloy elastic layer 42 is adjusted first, and residual deformation is reduced by increasing the clearance and promoting structural rebound; when the temperature threshold is reached before the pressure threshold, the heating or cooling device around the annular buffer cavity 31 is adjusted first, the freezing front and temperature gradient are controlled, and the development of frost heave is slowed down; when the pressure threshold is reached before the displacement and temperature thresholds, the phase change energy absorption layer 41, the shape memory alloy elastic layer 42, and the temperature control device are simultaneously controlled according to a preset ratio to quickly reduce the peak frost heave force.

[0080] The cloud-based collaborative module periodically receives monitoring data and control records from each tunnel section, updating digital model parameters and safety threshold reduction coefficients based on the results of multiple freeze-thaw cycles. For example, it can correlate the peak equivalent external pressure, maximum convergence, and minimum temperature of each cycle with the lining status and crack development under different control combinations to obtain the trend of safety margin changes. The cloud-based collaborative module then sends the updated threshold parameters and recommended control strategies to the edge control module, enabling the system to continuously adjust its control level based on permafrost changes and operational experience.

[0081] Through the above monitoring and control mechanisms, this invention achieves dynamic scheduling of frost heave energy paths and adaptive optimization of safety thresholds.

[0082] Example 3

[0083] The working principle of this invention is as follows:

[0084] Firstly, during the tunnel design phase, high-risk areas for frost heave are identified based on survey data such as ground temperature, lithology, and water content, dividing the tunnel route into high-risk, medium-risk, and low-risk zones. In the high-risk zones, a variable cross-section compensation section 11 is arranged, forming an annular buffer cavity 31 within it. A phase change energy absorption layer 41 and a shape memory alloy elastic layer 42 are respectively arranged at the arch crown and arch bottom. Simultaneously, a transition section 12 smoothly connects the variable cross-section compensation section 11 to the conventional section in terms of geometry and stiffness. A circumferential drainage component 61 and a thermal insulation and waterproofing layer 62 are arranged to form a boundary control system for drainage and thermal insulation.

[0085] Then, after the initial support is completed during the construction phase, the energy absorption module and intelligent monitoring node 51 are installed, the secondary lining 5 is poured, and the circumferential drainage component 61 and the thermal insulation and waterproof layer 62 are installed to form a complete lining and buffer structure.

[0086] After the tunnel is put into operation, the intelligent monitoring node 51 collects pressure, displacement, and temperature data according to a preset sampling cycle. This data is preprocessed into feature data by the local microcontroller and uploaded to the energy management control unit 52. The edge control module calculates the current equivalent external pressure p. eq The data is compared with a safety threshold, and based on the relationship between the monitored quantity and the threshold, an early warning, coordinated control, or de-controlled action is triggered. During coordinated control, the phase change energy absorption layer 41 absorbs part of the frost heave energy through the latent heat of phase change, the shape memory alloy elastic layer 42 absorbs and releases part of the frost heave energy through reversible deformation, and the temperature control device controls the freezing front and temperature gradient by adjusting the temperature field around the annular buffer cavity 31. The circumferential drainage component 61 promptly drains leaked water and meltwater, and the thermal insulation and waterproof layer 62 maintains a relatively stable environment in the buffer cavity.

[0087] After each freeze-thaw cycle, the cloud-based collaborative module analyzes and evaluates the monitoring data and control records for that cycle, updates the digital model and safety threshold reduction coefficient, and sends the updated results back to the edge control module, so that the control strategy for the next cycle achieves a more reasonable balance between safety and economy.

[0088] From the perspective of energy and deformation, this invention guides the frost heave energy that would normally act directly on the secondary lining to the annular buffer cavity 31, where it is jointly borne by the phase change energy absorption layer 41, the shape memory alloy elastic layer 42, and the hydrothermal boundary. From the perspective of control, a closed loop of perception-decision-execution-feedback-optimization is constructed through the intelligent monitoring node 51 and the energy management control unit 52, enabling the system to continuously adjust and optimize during long-term operation, achieving a high anti-frost heave effect through minor structural modifications and reasonable control strategies.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for intelligent compensation of frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, characterized in that... Specifically, the following steps are included: Based on geothermal, lithological and moisture content survey data, high-risk areas for frost heave were identified. The tunnel was divided into a variable cross-section compensation section, a conventional section and a transition section between the two. A continuous annular buffer cavity along the tunnel circumference was formed between the outer side of the secondary lining and the initial support of the variable cross-section compensation section. A phase change energy absorption layer was arranged at the arch top of the annular buffer cavity, a shape memory alloy elastic layer was arranged at the arch bottom of the annular buffer cavity, circumferential drainage components were arranged at the arch feet on both sides, and a thermal insulation and waterproof layer was set on the outside of the annular buffer cavity. Multiple intelligent monitoring nodes are deployed along the tunnel. Each intelligent monitoring node includes a pressure sensor, a displacement sensor, and a temperature sensor, as well as a local microcontroller for preprocessing multi-parameter monitoring data and identifying anomalies. Each intelligent monitoring node is connected to the energy management control unit via wired or wireless means, forming an edge monitoring network for the tunnel's frost heave condition. The energy management and control unit calculates the safe equivalent external pressure threshold based on the design value of the compressive strength of the secondary lining concrete, the equivalent thickness of the secondary lining, and the inner radius of the secondary lining. It also determines the displacement threshold and temperature threshold by combining the allowable convergence of the tunnel and the temperature limit of the key location. At least one of the equivalent external pressure threshold, displacement threshold, and temperature threshold is set as the main control threshold, and the remaining thresholds are set as parallel constraint thresholds. During tunnel operation, the energy management control unit continuously receives pressure, displacement and temperature data uploaded by each intelligent monitoring node, calculates the current equivalent external pressure and compares it with the main control threshold. When the monitored quantity reaches 90% of the main control threshold, an early warning is issued. When the monitored quantity reaches the main control threshold, linkage control is initiated. When the monitored quantity falls back to 70% of the main control threshold and the duration is not less than the set hysteresis time, linkage control is deactivated. During the coordinated control period, the energy management and control unit coordinates the working state of the phase change energy absorption layer, the pre-tightening or heating state of the shape memory alloy elastic layer, and the heating or cooling devices arranged around the annular buffer cavity based on the current frost heave state and historical operating data. This ensures that the frost heave energy is preferentially absorbed by the phase change energy absorption layer, and the remaining energy is released through elastic clearance and hydrothermal boundary adjustment, thereby reducing the equivalent frost heave force transmitted to the secondary lining and suppressing residual deformation after freeze-thaw cycles. After each complete freeze-thaw cycle, the energy management control unit records and archives the peak value of the equivalent external pressure, the peak value of the convergence, the minimum temperature, and the corresponding control behavior and control effect within that cycle. Based on the monitoring and control records of multiple freeze-thaw cycles, the reduction coefficients of the safety equivalent external pressure threshold, displacement threshold, and temperature threshold are updated, and the updated results are applied to subsequent operating cycles to achieve adaptive optimization of safety thresholds and control strategies throughout the entire life cycle.

2. The intelligent compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in claim 1, is characterized in that... The transition section has continuously and gradually changing cross-sectional parameters along the tunnel axis. The cross-sectional parameters include at least two of the following: the radial thickness of the annular buffer cavity, the unit surface heat capacity or surface density of the phase change energy absorption layer, and the circumferential arrangement pitch of the shape memory alloy elastic layer. The radial thickness of the annular buffer cavity is 0.10m-0.40m, the length of a single variable cross-section compensation section is 5m-20m, the centerline spacing between adjacent variable cross-section compensation sections is 50m-200m, and the length of the transition section is 1m-3m.

3. The intelligent compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in claim 1, is characterized in that... The local microcontroller of the intelligent monitoring node is configured to filter, statistically analyze, and extract features from the raw data of pressure, displacement, and temperature to form feature data including frost heave rate, temperature change rate, and convergence rate. It also identifies anomalies in the feature data and uploads only the feature data and anomaly markers to the energy management control unit.

4. The intelligent compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in claim 1, is characterized in that... The energy management and control unit includes an edge control module and a cloud collaboration module. The edge control module is used to perform online monitoring, equivalent external pressure calculation and graded trigger control. The cloud collaboration module is used to receive historical monitoring data and control records from multiple freeze-thaw cycles, construct a digital model of the tunnel-surrounding rock-annular buffer cavity, update the frost heave energy prediction parameters and the reduction coefficients of the safety equivalent external pressure threshold, displacement threshold and temperature threshold, and send the update results to the edge control module.

5. The intelligent compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in claim 1, is characterized in that... When the displacement threshold is reached before the master control threshold, the energy management control unit prioritizes adjusting the pre-tightening or heating state of the shape memory alloy elastic layer to increase the clearance and promote structural rebound. When the temperature threshold is reached before the master control threshold, the energy management control unit prioritizes adjusting the heating or cooling devices around the annular buffer cavity to change the position of the freezing front and reduce the cold input. When the equivalent external pressure threshold is reached before other thresholds, the phase change energy absorption layer, the shape memory alloy elastic layer, and the heating or cooling devices work together to perform regulation according to a preset ratio.

6. The intelligent compensation method for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in claim 1, is characterized in that... The variable cross-section compensation section, transition section and conventional section are arranged alternately along the longitudinal direction of the tunnel. The arrangement density of the variable cross-section compensation section in the high frost heave risk area is greater than that in the low frost heave risk area. Furthermore, based on the evaluation results of the frost heave energy and control effect of each section by the energy management and control unit, the length of the variable cross-section compensation section and the spacing between adjacent variable cross-section compensation sections are adjusted in zones.

7. A smart compensation system for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, characterized in that, A method for intelligent compensation of frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in any one of claims 1-6, includes: The tunnel lining structure subsystem is used to form variable cross-section compensation sections distributed along the longitudinal direction of the tunnel and transition sections set between the variable cross-section compensation sections and the conventional sections. An annular buffer cavity is set between the outer side of the secondary lining of the variable cross-section compensation section and the initial support. A phase change energy absorption layer is arranged on the arch top of the annular buffer cavity, a shape memory alloy elastic layer is arranged on the arch bottom of the annular buffer cavity, circumferential drainage components are set on both arch feet, and a thermal insulation and waterproof layer is set on the outer side of the annular buffer cavity. The monitoring subsystem includes multiple intelligent monitoring nodes deployed at different locations in the tunnel. Each intelligent monitoring node includes a pressure sensor, a displacement sensor, and a temperature sensor, as well as a local microcontroller for preprocessing monitoring data and identifying anomalies. Each intelligent monitoring node is connected to the energy management control unit via wired or wireless means. The energy management and control unit includes an edge control module and a cloud collaboration module. The edge control module is connected to the monitoring subsystem and is used to receive pressure, displacement, and temperature data uploaded by intelligent monitoring nodes, calculate the equivalent external pressure, and generate control commands for the phase change energy absorption layer, shape memory alloy elastic layer, and heating or cooling devices according to the pre-set safe equivalent external pressure threshold, displacement threshold, and temperature threshold and the hierarchical control rules. The cloud collaboration module is used to receive historical monitoring data and control records through the communication interface, construct a digital model of the tunnel-surrounding rock-annular buffer cavity, update the thresholds, and send the updated threshold parameters to the edge control module. The execution subsystem includes a temperature control actuator connected to the phase change energy absorption layer, a mechanical actuator connected to the shape memory alloy elastic layer, and a heating or cooling device arranged around the annular buffer cavity. The execution subsystem is connected to the energy management control unit to receive control commands and perform linkage control on the phase change energy absorption layer, the shape memory alloy elastic layer, and the heating or cooling device.

8. The intelligent compensation system for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring, as described in claim 7, is characterized in that... The local microcontroller of the intelligent monitoring node is configured to filter, statistically analyze, and extract features from the raw data of pressure, displacement, and temperature to form feature data including frost heave rate, temperature change rate, and convergence rate. It also identifies anomalies in the feature data and uploads the feature data and anomaly markers to the edge control module.

9. The intelligent compensation system for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring according to claim 1, characterized in that, The edge control module is configured to generate an early warning message when a certain monitored quantity reaches 90% of the corresponding safety threshold, generate a linkage control command when the monitored quantity reaches the safety threshold, and generate a release control command when the monitored quantity falls back to 70% of the safety threshold and the duration is not less than a set hysteresis time. The cloud collaboration module is configured to adjust the reduction coefficient of the safety threshold according to the peak value of the monitored quantity, control behavior and control effect of the current cycle after each freeze-thaw cycle, and send the adjustment result to the edge control module.

10. The intelligent compensation system for frost heave force in high-altitude permafrost variable cross-section tunnels based on cloud-edge collaborative structural health monitoring according to claim 1, characterized in that, The cross-sectional parameters of the transition section in the tunnel axis change continuously and gradually. The cross-sectional parameters include at least two of the following: the radial thickness of the annular buffer cavity, the unit surface heat capacity or surface density of the phase change energy absorption layer, and the circumferential arrangement pitch of the shape memory alloy elastic layer, thereby forming a smooth transition of stiffness and temperature field between the variable cross-section compensation section and the conventional lining section.

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