Full-scale adaptive loading system and method for shield segments

Abstract

The application provides a shield segment full-size self-adaptive loading system and method, and relates to the technical field of underground engineering. The shield segment full-size self-adaptive loading system comprises a ring-shaped counter-force wall, a test loading device and a support bearing device. The test loading device is installed on the ring-shaped counter-force wall and is used for automatically applying a normal load to the completed assembled shield segment ring. The support bearing device is installed on the ring-shaped counter-force wall and is used for abutting against the shield segment ring to record the interaction characteristics between the shield segment ring in a passive bearing state and the soil. The mixed loading scheme combining the load boundary mainly formed by the test loading device and the deformation boundary mainly formed by the support bearing device can restore the real stress state and the disease development mechanism of the shield segment in combination with related information such as tunnel section measurement data.

Description

Technical Field

[0001] This invention relates to the field of underground engineering technology, and more specifically, to a full-scale adaptive loading system and method for tunnel lining segments. Background Technology

[0002] Shield tunnels have become the preferred form of construction for modern rail transit projects. They are unaffected by surface traffic, waterways, shipping, tides, seasons, and climate, and offer advantages such as rapid construction speed, excellent settlement control, good environmental protection, and adaptability to urban areas and densely built-up areas. They are currently in a phase of rapid promotion, application, and development. However, during actual construction and operation, the actual stress and deformation characteristics of shield tunnel segments differ significantly from the design conditions due to various factors such as changes in soil properties within the tunnel body and alterations in external environmental conditions. This results in a series of structural defects, such as bolt breakage, joint damage, concrete spalling, and cracks, which negatively impact the operational safety and long-term stability of the tunnel. The inventors discovered that this phenomenon is mainly due to a lack of understanding of key technical issues such as the ultimate bearing capacity of shield tunnel segments and the development process of structural defects.

[0003] Shield tunnel segment loading tests are currently the most intuitive and accurate testing method for revealing the stress-deformation characteristics, ultimate bearing capacity, and disease development mechanisms of shield tunnel segments. At present, many scholars both domestically and internationally have developed prototype testing loading devices for shield tunnel segments. These devices can be categorized by segment placement method (lying or standing) and by the number of rings (single-ring or multi-ring). Load application schemes mainly include several categories such as tension jacks and ring clamp forces. The load values ​​can be actively controlled to simulate the water and soil pressure and longitudinal forces that may occur around the shield tunnel, performing horizontal and vertical loading. To simulate the various load distribution patterns that may exist around the shield tunnel as much as possible and to achieve the loading technology requirements of asymmetric loads or continuous changes in multiple load conditions, a series of improvement schemes have been proposed, such as adding resistance springs (CN110618037A) and an asymmetric load loading test system (CN112857988A).

[0004] The inventors discovered during their research that existing testing systems have at least the following technical problems:

[0005] 1. Simple boundary constraints for shield tunnel segments: The structural loads of shield tunnel segments are all provided by pressurized hydraulic cylinders or jacks, which are mostly single loading schemes with active load control. The load distribution pattern around the shield tunnel segments is adjusted by adjusting the load value, and research is conducted on their deformation and defect development process. The jacking load within each hydraulic cylinder group is calculated by structural software, which is difficult to test on site, and there are significant differences between indoor and outdoor test results.

[0006] 2) The load application direction of the hydraulic cylinder or jack cannot be changed: Before the full-scale loading test of the tunnel segment, the load application direction is always towards the center of the segment; however, during the actual segment loading process, the continuous deformation of the tunnel segment causes the load application direction to change, resulting in eccentricity, which in turn affects the test results. This difference in the test boundary conditions is inconsistent with the actual operating conditions of the segment and the theoretical calculation methods. Currently, existing segment loading test systems cannot achieve the loading technology requirement of adaptive dynamic adjustment of the load application direction as the segment deforms;

[0007] 3) The size of the shield tunnel segments cannot be adjusted: At present, the existing full-scale loading test systems for tunnel segments are mostly developed for shield tunnels of specific sizes and shapes. They cannot meet the test loading technical requirements of the same system but different inner diameters of the tunnel segments, and cannot meet the development needs of tunnel and underground engineering construction. Summary of the Invention

[0008] The purpose of this invention is to provide a full-scale adaptive loading system and method for tunnel lining segments, which can improve at least one technical defect existing in the prior art.

[0009] The embodiments of the present invention are implemented as follows:

[0010] In a first aspect, the present invention provides a full-scale adaptive loading system for tunnel boring machine segments, comprising:

[0011] The system includes an annular reaction wall, a test loading device, and a support device. The test loading device is installed on the annular reaction wall and is used to automatically apply a normal load to the assembled shield tunnel segment ring. The support device is installed on the annular reaction wall and is used to abut against the shield tunnel segment ring to record the interaction characteristics between the shield tunnel segment ring and the soil under passive bearing conditions.

[0012] In an optional implementation, the annular reaction wall is configured as a reinforced concrete wall.

[0013] In an optional embodiment, the test loading device includes multiple loading units arranged around the annular reaction wall. Each loading unit includes an embedded part, a transition support, a loader, and a force transmission support. The embedded part is fixed to the annular reaction wall. The transition support is rotatably engaged with one end of the loader, and the force transmission support is rotatably engaged with the other end of the loader. The force transmission support is used to apply the load to the outer circumferential surface of the shield tunnel segment ring.

[0014] In an optional implementation, the loader is configured as a loading cylinder equipped with a constant pressure relief valve.

[0015] In an optional embodiment, the dimensions of the transition bracket in the telescopic direction of the loader are adjustable.

[0016] In an optional embodiment, the loading unit further includes an arc-shaped loading plate connected to the force transmission support. The arc-shaped loading plate has a concave surface for contacting the outer circumferential surface of the shield tunnel segment ring.

[0017] In an optional embodiment, the arc-shaped loading plate includes a connected metal plate and a rubber pad, the metal plate having a concave surface, the rubber pad being located on the concave surface, and the rubber pad being used to abut against the tunnel segment ring.

[0018] In an optional embodiment, the test loading device further includes two metal cover plates, which are respectively disposed at both ends of the shield segment ring in the axial direction. Each metal cover plate has a lubrication layer on its surface that contacts the shield segment ring. The metal cover plates are used to simulate the interaction force between adjacent shield segment rings.

[0019] In an optional embodiment, the support device includes multiple sets of pressure sensors and a support bracket with controllable deformation and optional filling material. The support bracket is used to be clamped between the annular reaction wall and the shield segment ring, and the multiple sets of pressure sensors are distributed on the support bracket.

[0020] Secondly, the present invention provides a full-scale adaptive loading method for tunnel lining segments, based on the full-scale adaptive loading system for tunnel lining segments described in any of the foregoing embodiments, the loading method comprising:

[0021] Step S100: Excavate a pit at the proposed test location to form a shield tunnel segment placement area;

[0022] Step S200: Lay a concrete base slab at the bottom of the foundation pit to form a ring reaction wall around the foundation pit;

[0023] Step S300: Within the shield tunnel segment placement area, complete the on-site assembly of the shield tunnel segment ring; and deploy the stress characteristic monitoring system, deformation monitoring system, and defect image acquisition system for the shield tunnel segment ring.

[0024] Step S400: Install a test loading device and a support device between the annular reaction wall and the shield segment placement area.

[0025] In an optional implementation, the steps of arranging the stress characteristic monitoring system, deformation monitoring system, and defect image acquisition system for the shield tunnel segment ring include:

[0026] During the assembly of the shield tunnel segment rings, foil strain gauges, rebar gauges, and surface strain sensors are arranged at the joints and on the inner and outer sides of adjacent segments; a total station is arranged in the area enclosed by the shield tunnel segment rings; and a laser scanner is arranged in the area enclosed by the shield tunnel segment rings.

[0027] The beneficial effects of the embodiments of the present invention are:

[0028] In summary, the full-scale adaptive loading system for tunnel segments provided in this embodiment employs a hybrid loading scheme that combines a load boundary primarily based on the experimental loading device with a deformation boundary primarily based on the support device. Combined with tunnel cross-section measurement data and other relevant information, it can reconstruct the true stress state and disease development mechanism of the tunnel segments. Generally, the soil layers surrounding existing tunnel bodies are composed of various soil layers. For water-sensitive soils, once immersed in water, they weaken significantly, the resistance provided by the soil decreases significantly, and structural deformation continues to develop. In the implementation of this embodiment, by controlling the experimental load values ​​in zones and grades, the active loading technology requirements under different load distribution patterns and symmetrical or asymmetrical load conditions can be achieved. For non-water-sensitive soils, their properties do not change significantly before and after immersion in water, providing stable support for the tunnel structure. Furthermore, the structural deformation within the corresponding range remains relatively small. Correspondingly, in the implementation of this embodiment, by setting up support devices with variable filling materials, a dynamically variable passive bearing capacity can be continuously provided to the tunnel segments while controlling structural deformation. Thus, the full-scale adaptive loading system for shield tunnel segments provided in this embodiment distinguishes between passive bearing and active loading regions, which can simulate the service status of shield tunnels under different combinations of soil layer characteristics, obtain the mechanical response characteristics of the segment structure under the condition of local rock resistance attenuation, and provide an effective testing method for a deeper understanding of the stress deformation characteristics and disease development mechanism of shield tunnels.

[0029] Meanwhile, during the test, as various loads are applied and structural deformation develops, the actual force values ​​are constantly changing dynamically. Therefore, the hybrid loading scheme provided in this embodiment, which combines the load boundary mainly based on the test loading device and the deformation boundary mainly based on the support device, distinguishes between the active bearing and passive bearing areas, thus more closely approximating the actual service state of the shield tunnel segment and obtaining more valuable test results.

[0030] Furthermore, by setting transition supports and force transmission supports before and after the loader to form an adaptive steering system, the loading technology requirement of continuously and dynamically adjusting the load direction according to the deformation of the shield tunnel segments during the test can be achieved. By setting transition supports between the loader and the annular reaction wall, the test loading technology requirements for shield tunnel segments of different diameters can be met. By configuring constant pressure relief valves on the loading cylinders and using multiple loading cylinders in conjunction with the hydraulic control system, the loading requirements for shield tunnel segments under different load distribution patterns and symmetrical or asymmetrical load conditions can be met, while satisfying the loading technology requirement of constant bearing force during the deformation of the shield tunnel segments. By arranging a lubrication system, deformation monitoring system, defect image acquisition system, and segment ring stress characteristic monitoring system, research on the stress and deformation characteristics and defect development mechanisms of shield tunnel segments under different load distribution patterns can be carried out. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the full-scale adaptive loading system for tunnel segments according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the full-scale adaptive loading system for tunnel segments according to an embodiment of the present invention from another perspective;

[0034] Figure 3 This is a schematic diagram of the structure of the shield tunnel segment full-scale adaptive loading system and the hydraulic control system in accordance with an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the shield tunnel segment ring according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the assembly structure of the loading unit according to an embodiment of the present invention;

[0037] Figure 6 This is a partial structural schematic diagram of the shield tunnel segment ring and loading unit according to an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the cooperation structure between the shield tunnel segment ring and the stress characteristic monitoring system according to an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the annular deformation of the tunnel lining segments.

[0040] icon:

[0041] 001-Foundation Pit; 002-Shield Segment Ring; 021-First Standard Block; 022-Second Standard Block; 023-Third Standard Block; 024-First Adjacent Block; 025-Capping Block; 026-Second Adjacent Block; 100-Annular Reaction Wall; 200-Test Loading Device; 210-Loading Unit; 211-Embedded Part; 212-Transition Support; 213-Loader; 2131-Cylinder Seat; 2132-Connecting Seat; 214-Force Transmission Support; 2 15-Arc-shaped loading plate; 2151-Metal plate; 2152-Rubber pad; 216-First pin; 217-Second pin; 220-Hydraulic control system; 230-First metal cover plate; 240-Second metal cover plate; 300-Support device; 310-Support bracket; 320-Pressure sensor; 400-Foil strain gauge; 410-Reinforcement gauge; 420-Surface strain sensor; 500-Total station; 600-3D laser scanner. Detailed Implementation

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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 commonly used when the product of this invention is in 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, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] 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.

[0047] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] Example of a full-scale adaptive loading system for tunnel segments

[0049] Please combine Figures 1-7 This embodiment provides a full-scale adaptive loading system for shield tunnel segment ring 002, which can automatically adjust the load application direction according to the actual deformation of the shield tunnel segment during the test, maintaining consistency with the normal direction of the shield tunnel segment in the corresponding section. The load application value meets the loading technical requirements for shield tunnel segments under different load distribution patterns, symmetrical or asymmetrical load conditions, and the obtained experimental results are highly accurate and reliable.

[0050] It should be noted that "full size" means that the dimensions of the shield tunnel segment ring 002 are consistent with the dimensions of the shield tunnel segment rings actually in service.

[0051] Please combine Figure 4In this embodiment, the shield tunnel segment ring 002 is described as a single ring. The shield tunnel segment ring 002 includes a first standard block 021, a second standard block 022, a third standard block 023, a first adjacent block 024, a capping block 025, and a second adjacent block 026 connected end to end. Adjacent segments can be fixedly connected by bolts or the like. During the test, the second standard block 022 and the third standard block 023 are located below the first standard block 021 and the first adjacent block 024.

[0052] In this embodiment, the full-scale adaptive loading system for the shield tunnel segment ring 002 includes an annular reaction wall 100, a test loading device 200, and a support device 300. The test loading device 200 is installed on the annular reaction wall 100 and is used to automatically apply normal loads to the assembled shield tunnel segment ring 002. The support device is installed on the annular reaction wall 100 and is used to abut against the shield tunnel segment ring 002 to record the interaction characteristics between the shield tunnel segment ring 002 and the soil under passive bearing conditions.

[0053] As mentioned above, a hybrid loading scheme combining the load boundary, mainly based on the test loading device 200, and the deformation boundary, mainly based on the support device 300, is adopted. Combined with relevant data such as tunnel cross-section measurement data, the true stress state and defect development mechanism of the shield tunnel segments can be restored. In this way, the data obtained from the test is more accurate and more reliable.

[0054] Please combine Figure 1 and Figure 2 In this embodiment, optionally, an annular reaction wall 100 is installed in the foundation pit 001. The annular reaction wall 100 is a reinforced concrete structure. The foundation pit 001 is excavated at a preset location. The foundation pit 001 is a circular pit, and its diameter is set as needed to accommodate the test equipment. The annular reaction wall 100 is installed on the periphery of the foundation pit 001, and its pouring thickness is set as needed. The annular shear wall provides support for the test loading device 200, facilitating the application of loads to the tunnel lining segments.

[0055] Please combine Figures 5-6In this embodiment, optionally, the test loading device 200 includes multiple loading units 210, which are arranged circumferentially around the annular reaction wall 100, and the positions of the multiple loading units 210 are distributed in the active loading area of ​​the shield tunnel segment ring 002. Optionally, each loading unit 210 includes an embedded part 211, a transition support 212, a loader 213, a force transmission support 214, and an arc-shaped loading plate 215. The embedded part 211 is a metal component, which is fixed inside the annular reaction wall 100 during the manufacturing of the annular reaction wall 100, and is partially exposed in the area enclosed by the annular reaction wall 100. The transition bracket 212 can be configured as an adjustable-length bracket. It is installed between the embedded part 211 and the loader 213. By adjusting the length of the transition bracket 212, the distance between the loader 213 and the shield tunnel segment ring 002 can be adjusted, thus adapting to the loading of segments of different sizes without changing the loader 213, providing flexibility in use. The loader 213 can be a loading cylinder or a jack; in this embodiment, a loading cylinder is used as an example. A cylinder seat 2131 is provided at the end of the cylinder body of the loader 213 away from the piston rod, and a connecting seat 2132 is provided at the end of the piston rod away from the cylinder body. One end of the transition bracket 212 is fixedly connected to the embedded part 211, and the other end is rotatably connected to the cylinder seat 2131 via a first pin 216. The force transmission support 214 is rotatably connected to the connecting seat 2132 via a second pin 217. The first pin 216 and the second pin 217 are arranged in parallel, and the axes of the first pin 216 and the second pin 217 are both parallel to the axis of the shield tunnel segment ring 002. The arc-shaped loading plate 215 includes a connected metal plate 2151 and a rubber pad 2152. The metal plate 2151 is an arc-shaped plate with a concave surface, and the rubber pad 2152 is attached to the concave surface, also forming an arc-shaped plate structure. The metal plate 2151 and the force transmission support 214 can be fixedly connected by welding or other methods. The side of the rubber pad away from the metal plate 2151 is used to contact the outer peripheral surface of the shield tunnel segment. When the loader 213 is activated, the piston rod extends. Since the cylinder body is connected to the transition support 212, and the transition support 212 is connected to the annular reaction wall 100 through the embedded part 211, the position of the cylinder body remains unchanged. The piston rod drives the arc-shaped loading plate 215 to abut against the shield tunnel segment ring 002, thereby applying a load to the shield tunnel segment ring 002. During the application of the load, the shield tunnel segment ring 002 deforms. With the cooperation of the transition support 212 and the force transmission support 214, the loader 213 can adaptively adjust its position so that the load applied by the loader 213 to the shield tunnel segment ring 002 is always along the normal direction of the segment ring. That is, the loader 213 has an adaptive steering function, which can effectively improve the test error caused by the eccentric load generated by the deformation of the shield tunnel segment during the test.Meanwhile, the load is applied to the shield tunnel segment through the arc-shaped loading plate 215. The arc-shaped loading plate 215 can be closely attached to the outer circumference of the shield tunnel segment through the rubber pad 2152, realizing the loading technology requirement of converting point load to surface load. This makes the load distribution on the shield tunnel segment more uniform and effectively avoids the influence of the stiffness difference between the shield tunnel segment and the loader 213 and the uneven load distribution on the test results.

[0056] Please combine Figure 3 It should be noted that the loader 213 can be a loading cylinder, and there can be multiple loaders 213, that is, multiple loading cylinders. Multiple loading cylinders can be controlled by a hydraulic control system 220, allowing them to work collaboratively. For example, in this embodiment, two sets of hydraulic control systems 220 can work collaboratively to control multiple loading cylinders. During the test, the jacking force of each loading cylinder is synchronously adjusted by the hydraulic control system 220 to achieve dynamic loading of the tunnel lining segments. During this period, the jacking stroke, jacking force, and values ​​of stress sensors inside the support bearings, the stress and deformation characteristics of the tunnel lining segments, and the development process of defects should be recorded in real time for each loading cylinder. The grouping principles of each set of cylinders, the jacking load values, and their increase / decrease conditions should be reasonably determined based on the specific test conditions using the load-structure method, the stratum-structure method, or other calculation methods.

[0057] It should be understood that the transition bracket 212 can be detachably connected to the embedded part 211 and the cylinder seat 2131. In this way, by replacing the transition bracket 212, the size of the transition bracket 212 can also be adjusted, so as to be applied to the loading of shield tunnel segment rings 002 of different sizes.

[0058] Optionally, all loading cylinders are equipped with constant pressure relief valves to meet the loading technical requirements of stroke retraction when the holding force of each group of loading cylinders remains constant or increases, allowing the deformation of the shield segment ring 002 to fully develop during the test. In selecting specific cylinder models, the cylinder type should be chosen that matches the expected deformation and jacking load, taking into account the test design conditions. During the test, the jacking force and actual jacking stroke of the cylinders should be displayed in real time. This serves two purposes: firstly, it can indirectly verify the test results of the shield segment deformation monitoring system; secondly, it allows for the calculation of the deformation of the active loading system of the cylinders and the reaction wall foundation reinforcement area during the test, providing a certain reference value for ensuring the reliability of the test results.

[0059] In addition, the number and position of the loading cylinders can be adjusted as needed, and can be used with single-ring segments and multi-ring segments to simulate different load conditions.

[0060] In this embodiment, optionally, the test loading device 200 further includes two metal cover plates, referred to as a first metal cover plate 230 and a second metal cover plate 240 for ease of description. Both the first metal cover plate 230 and the second metal cover plate 240 are annular plates. The first metal cover plate 230 and the second metal cover plate 240 are respectively disposed on the two end faces of the shield tunnel segment ring 002. Furthermore, lubricating material is also disposed on the plate surfaces of the first metal cover plate 230 and the second metal cover plate 240 that are in contact with the shield tunnel segment ring 002. By selecting lubricating materials with different frictional characteristics, the stress, deformation, and defect development patterns of the shield tunnel segment ring 002 under different inter-ring effect characteristics can be reflected.

[0061] Please combine Figure 3 In this embodiment, optionally, the support device 300 includes multiple sets of pressure sensors 320 and a support bracket 310 with controllable deformation and selectable filling material. The support bracket 310 is used to be clamped between the annular reaction wall 100 and the shield tunnel segment ring 002, and the multiple sets of pressure sensors 320 are distributed on the support bracket 310. Specifically, the outer side of the support bracket 310 abuts against the annular reaction wall 100, and the inner side abuts against the second standard block 022 and the third standard block 023 through a filling layer. The area of ​​the support bracket 310 abutting against the second standard block 022 and the third standard block 023 can be adjusted as needed. By adjusting the structure or material of the support bracket 310, its deformation capacity can be adjusted. Furthermore, the deformation capacity of the support bracket 310 is less than that of the shield tunnel segment, that is, the strength of the support bracket 310 is higher, and it can play the role of supporting the annular tunnel segment. By setting up support bracket 310, the loading technical requirement that the deformation within a local area of ​​the shield tunnel segment ring 002 remains consistent with the actual measured deformation during the test can be met. Please refer to... Figure 8 , Figure 8 This is a schematic diagram of cross-sectional deformation obtained from a three-dimensional laser scanning test of a tunnel section. The deformation pattern does not strictly conform to the traditional elliptical deformation characteristics, which are traditionally considered to be horizontal oval and vertical oval shapes. Specifically, under the influence of external factors such as ground overload and changes in soil properties within the tunnel body, the tunnel as a whole experiences arch subsidence deformation and horizontal extrusion deformation on both sides. Within the invert arch area, i.e., at the track bed location, the deformation remains within a relatively small range.

[0062] The full-scale adaptive loading system for shield tunnel segment ring 002 provided in this embodiment can achieve mixed loading under two boundary constraints: hydraulic cylinder load and support deformation. Using actual tunnel measurement data as input boundary conditions, it can obtain relatively accurate and reasonable test results. Simultaneously, the system employs an adaptive steering structure for the loading hydraulic cylinder, which can eliminate test errors caused by eccentric loads due to shield segment deformation during testing. Furthermore, the system uses an adjustable-size test loading device 200, which can meet the test requirements for various shield segment inner diameters. This provides a feasible and effective test method for in-depth analysis of the stress-deformation characteristics and defect mechanisms of shield tunnel segments, resulting in significant economic and social benefits.

[0063] Example of Full-Scale Adaptive Loading Method for Shield Tunnel Segments

[0064] This embodiment also provides a full-scale adaptive loading method for shield tunnel segment ring 002, which includes the following steps:

[0065] Step S100: Excavate a foundation pit 001 at the proposed test location to form a shield tunnel segment placement area.

[0066] In step S200, a concrete base slab of a certain thickness is laid at the bottom of the foundation pit 001, and a first metal cover plate 230 containing lubricant is placed. The selection of lubricant is determined comprehensively based on the inter-ring effect characteristics of the actual shield tunnel lining ring. A ring reaction wall 100 is formed by reinforcing the foundation around the foundation pit 001. Embedded parts 211 are pre-set in the ring reaction wall 100, and the number and position of the embedded parts 211 are set as needed.

[0067] In step S300, a support bracket 310 is installed at a predetermined position on the annular reaction wall 100, and concrete or other materials are poured into the cavity formed by the support bracket 310. Multiple pressure sensors 320 are pre-embedded in the concrete. The assembly position of the support bracket 310 is consistent with the pseudo-deformation control area passively borne by the shield tunnel segment ring 002.

[0068] In step S400, within the shield tunnel segment placement area, the shield tunnel segment ring 002 is assembled on-site onto the first metal cover plate 230; a stress characteristic monitoring system, a deformation monitoring system, and a defect image acquisition system for the shield tunnel segment ring 002 are then deployed. During the assembly of the shield tunnel segment ring 002, a stress characteristic monitoring system, primarily composed of foil strain gauges 400, rebar gauges 410, and surface strain sensors 420, is deployed at the joints and inner and outer sides of adjacent segments. A deformation monitoring system, primarily composed of a total station 500, and a defect image acquisition system, primarily composed of a 3D laser scanner 600, are installed at the center of the shield tunnel segment ring 002. Both the total station 500 and the 3D laser scanner 600 are located in the central position of the shield tunnel segment placement area.

[0069] In step S500, a test loading device 200 and a support device 300 are installed between the annular reaction wall 100 and the shield segment placement area.

[0070] In step S600, multiple loading units 210 are installed sequentially and step-by-step along the circumference of the annular reaction wall 100, using the position of the embedded part 211 as a reference, and the transition bracket 212 of the loading unit 210 is connected to the corresponding embedded part 211. Multiple loading cylinders are sequentially connected to the hydraulic control system 220 according to the load grouping control principle. During installation, ensure that the arc-shaped loading plate 215 is in contact with the outer circumferential surface of the shield tunnel segment ring 002; the relevant equipment must be debugged before, during, and after the installation of the shield tunnel segment ring 002.

[0071] In step S700, the hydraulic control system 220 is used to adjust the jacking amount of the oil cylinders in groups. When the stress and strain test data of the shield segment ring 002 changes slightly, it indicates that the arc-shaped loading plate has made close contact with the shield segment ring 002 and meets the test conditions.

[0072] In step S800, a second metal cover plate 240 with a surface coated with lubricant is placed above the shield segment ring 002. The choice of lubricant material should be determined based on the interaction characteristics between adjacent shield segment rings.

[0073] In step S900, the jacking force of each loading cylinder is synchronously adjusted through the hydraulic control system 220 to achieve dynamic loading of the tunnel lining segments. During this process, the jacking stroke, jacking force, and stress sensor values ​​inside the support bearings of each loading cylinder, as well as the stress-deformation characteristics and defect development process of the tunnel lining segments, should be recorded in real time. The grouping principles of each set of cylinders, the jacking load values, and their increase or decrease conditions should be reasonably determined based on the specific test conditions using the load-structure method, the stratum-structure method, or other calculation methods.

[0074] The loading method provided in this embodiment can restore the true stress state and disease development mechanism of the tunnel lining segments, and the obtained test results are highly accurate and have high reference value.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A full-scale adaptive loading system for tunnel lining segments, characterized in that, include: The annular reaction wall, the test loading device, and the support device are used to automatically apply normal loads to the assembled shield tunnel segment rings. The support device is installed on the annular reaction wall and is used to abut against the shield tunnel segment rings to record the interaction characteristics between the shield tunnel segment rings and the soil under passive bearing conditions. The test loading device includes multiple loading units arranged around the annular reaction wall. Each loading unit includes an embedded part, a transition support, a loader, and a force transmission support. The embedded part is fixed to the annular reaction wall. The transition support is rotatably engaged with one end of the loader, and the force transmission support is rotatably engaged with the other end of the loader. The force transmission support is used to apply the load to the outer circumferential surface of the shield tunnel segment ring.

2. The full-scale adaptive loading system for tunnel segments according to claim 1, characterized in that: The annular reaction wall is constructed of reinforced concrete.

3. The full-scale adaptive loading system for tunnel segments according to claim 1, characterized in that: The dimensions of the transition bracket are adjustable in the telescopic direction of the loader.

4. The full-scale adaptive loading system for tunnel segments according to claim 1, characterized in that: The loading unit further includes an arc-shaped loading plate, which is connected to the force transmission support. The arc-shaped loading plate has a concave surface, which is used to abut against the outer circumferential surface of the shield tunnel segment ring.

5. The full-scale adaptive loading system for tunnel segments according to claim 4, characterized in that: The arc-shaped loading plate includes a connected metal plate and a rubber pad. The metal plate has a concave surface, and the rubber pad is located on the concave surface. The rubber pad is used to abut against the shield tunnel segment ring.

6. The full-scale adaptive loading system for tunnel segments according to claim 1, characterized in that: The test loading device also includes two metal cover plates, which are respectively disposed at both ends of the shield segment ring in the axial direction. Each metal cover plate has a lubrication layer on its plate surface that contacts the shield segment ring. The metal cover plates are used to simulate the interaction force between adjacent shield segment rings.

7. The full-scale adaptive loading system for tunnel segments according to any one of claims 1-6, characterized in that: The support device includes multiple pressure sensors and a support bracket with controllable deformation and selectable filling material. The support bracket is used to be clamped between the annular reaction wall and the shield segment ring. The multiple pressure sensors are distributed on the support bracket.

8. A full-scale adaptive loading method for tunnel lining segments, based on the full-scale adaptive loading system for tunnel lining segments according to any one of claims 1-7, characterized in that, The loading method includes: Step S100: Excavate a pit at the proposed test location to form a shield tunnel segment placement area; Step S200: Lay a concrete base slab at the bottom of the foundation pit to form a ring reaction wall around the foundation pit; Step S300: Within the shield tunnel segment placement area, complete the on-site assembly of the shield tunnel segment ring; and deploy the stress characteristic monitoring system, deformation monitoring system, and defect image acquisition system for the shield tunnel segment ring. Step S400: Install a test loading device and a support device between the annular reaction wall and the shield segment placement area.

9. The full-scale adaptive loading method for shield tunnel segments according to claim 8, characterized in that: The steps for arranging the stress characteristic monitoring system, deformation monitoring system, and defect image acquisition system for the shield tunnel segment rings include: During the assembly of the shield tunnel segment rings, foil strain gauges, rebar gauges, and surface strain sensors are arranged at the joints and on the inner and outer sides of adjacent segments; a total station is arranged in the area enclosed by the shield tunnel segment rings; and a laser scanner is arranged in the area enclosed by the shield tunnel segment rings.

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