Surrounding rock deformation and supporting structure stress test method, electronic device and storage medium

Abstract

This invention relates to the field of tunnel construction technology, and mainly provides a method for testing surrounding rock deformation and support structure stress, electronic equipment, and storage medium. The method for testing surrounding rock deformation and support structure stress provided by this invention, through a systematic testing process and scientific testing methods, solves the technical problems of existing in-situ tunnel testing techniques, such as difficulty in achieving controllable deformation, incomplete data acquisition, and insufficient reliability of test results. This provides effective technical support for the safe construction and long-term stability control of deeply buried soft rock tunnels.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, specifically relating to a method for testing surrounding rock deformation and support structure stress, electronic equipment, and storage medium. Background Technology

[0002] In recent years, the water conveyance tunnels in several long-distance water diversion projects that have been built or are planned have been constrained by route selection. They often have to pass through mountainous areas with complex geological structures, facing many unfavorable factors such as harsh natural environment, high seismic intensity, and complex topographic and geological conditions. In particular, when passing through soft rock strata with high ground stress, they face the risk of large deformation of soft rock. The main hazards are manifested as deformation of the surrounding rock, failure of support, frequent TBM jamming, and even cracking of the secondary lining, which affects the service life of the structure, seriously restricts the progress of project construction, and threatens the long-term safety and stability of the tunnel.

[0003] Currently, in-situ testing is an indispensable and crucial step in accurately obtaining the physical and mechanical parameters of soil and rock masses, evaluating the performance of support structures, or verifying design schemes. The conventional method for conducting in-situ tests in underground caverns involves constructing a reaction system and a loading system on-site within the cavern after excavation to create the test area. Specifically, a closed or semi-closed rigid reaction frame is typically built inside the cavern using large steel components, and a hydraulic loading device is placed between the reaction frame and the cavern wall or support structure to be tested. The loading device is driven by a hydraulic system, applying radial or specific directional loads to the test surface through structures such as arc-shaped pressure plates to simulate the actual stress state. The stress data obtained through monitoring provides a research reference for understanding the deformation patterns of the surrounding rock.

[0004] However, existing testing systems suffer from complex structural designs and poor overall integrity, making it difficult to provide sufficiently stable and uniform distributed reaction force support for large-sized circular arc pressure plates under heavy loads. This can easily lead to localized stress concentration, affecting the accuracy of test results. Furthermore, conventional monitoring devices often cannot effectively coordinate with the tunnel construction process, failing to achieve active control and real-time feedback of the deformation process. This results in delayed test data, hindering timely and effective guidance for dynamic construction. Therefore, it is necessary to develop an in-situ testing device capable of adapting to complex geological conditions and achieving controllable deformation, providing technical support for the safe construction and long-term stability control of deeply buried soft rock tunnels. Summary of the Invention

[0005] This invention provides a method, electronic device, and storage medium for testing surrounding rock deformation and support structure stress, which solves the technical problem of insufficient authenticity and reliability of test results caused by structural defects in existing in-situ tunnel testing devices. The specific technical solution is as follows:

[0006] In a first aspect, embodiments of the present invention provide a method for testing the deformation of surrounding rock and the stress on support structures, including:

[0007] A method for testing the deformation of surrounding rock and the stress of support structures, comprising:

[0008] Step 1: Set up an in-situ testing device in the test tunnel. The in-situ testing device includes a ring-shaped reaction frame and multiple loading mechanisms arranged at equal angles on the outer ring of the reaction frame. The loading mechanism includes a loading cylinder and an arc-shaped pressure plate. The loading cylinder is connected to the reaction frame and its output end is arranged radially outward along the reaction frame. The arc-shaped pressure plate is connected to the output end and abuts against the surrounding rock of the tunnel.

[0009] Step 2: Continue excavating the test tunnel and monitor the response load of the surrounding rock of the tunnel on the circular arc pressure plate and the displacement of the circular arc pressure plate;

[0010] Step 3: Set multiple displacement levels, control the extension and retraction of the output end of the loading cylinder to apply displacement to the arc plate, and monitor the response load of the arc plate under different displacement levels;

[0011] Step 4: Apply load and unload the loading cylinder step by step according to the predetermined load gradation, and conduct cyclic loading and unloading tests to monitor the rebound displacement of the surrounding rock of the tunnel.

[0012] Step 5: Disassemble the in-situ test device in reverse order.

[0013] Optionally, step 2 includes:

[0014] The actual test force applied by the loading cylinder is measured in real time using a force sensor, and the displacement value at the output end is monitored synchronously using a displacement sensor.

[0015] During the first time period, the data acquisition interval of the force sensor and the displacement sensor is ≤5 minutes. During the second time period after the first time period, the data acquisition interval of the force sensor and the displacement sensor is ≤30 minutes. Based on the acquired data, load-tunneling distance curves and load-time curves are plotted. When the difference between the current response load of the arc pressure plate and the response load 24 hours ago is ≤5% of the response load acquired 24 hours ago, the load is determined to be stable and the step is stopped.

[0016] Optionally, the method may further include the following steps before step 2:

[0017] The temperature and humidity of the test area are continuously monitored. When the temperature change is ≤ ±1℃ and the humidity change is ≤ ±5%, the loading mechanism is calibrated by a servo controller.

[0018] The loading cylinder is controlled to preload at 5%-10% of its maximum output to verify the detection accuracy of the force sensor and the displacement sensor.

[0019] Optionally, step 3 includes:

[0020] After outputting the displacement at each stage, the supporting force of the arc plate is immediately collected by the force sensor, and collected again after 10 minutes.

[0021] When the difference between two consecutive support force acquisition values ​​is less than 5% of the ratio of the first acquisition value under the same displacement level and the last acquisition value under the previous displacement level, the next level of displacement is output.

[0022] Repeat the above steps to plot the stress-displacement curve and save the data.

[0023] Optionally, step 4 includes:

[0024] The load is divided into 10 to 15 levels according to 1.2 times the engineering design pressure, and the loading cylinder is controlled to apply the load level by level.

[0025] Immediately after each load level is applied, the detection data from the force sensor and the displacement sensor are collected, and the data is collected again after 10 minutes. When the load stability judgment condition is met, the next load level is applied. The relationship between the support force and the deformation of the tunnel surrounding rock is recorded and the load-displacement curve is plotted.

[0026] Optionally, when the loading cylinder applies a load, the loading cylinders in the plurality of loading mechanisms are loaded synchronously and uniformly, and the maximum output of each loading cylinder is 150T.

[0027] Optionally, step 4 further includes:

[0028] The loading cylinders are controlled to depressurize in stages, with the maximum applied load divided into 10 to 15 levels.

[0029] Immediately after each load is depressurized, the detection data of the force sensor and the displacement sensor are collected, and the data is collected again after 10 minutes. When the judgment condition of load stability is met, the next load depressurization is carried out. The relationship between the support force and the deformation of the tunnel surrounding rock is recorded and the load-displacement curve is plotted.

[0030] Optionally, step 4 further includes:

[0031] The loading cylinder is subjected to a cyclical process of applying load and depressurizing in stages for 2 to 3 rounds. The load-displacement curves in each round are continuously monitored, and the plastic deformation characteristics of the tunnel surrounding rock are analyzed based on the load-displacement curves.

[0032] In a second aspect, embodiments of the present invention provide an electronic device, comprising:

[0033] processor;

[0034] Memory used to store instructions that can be executed by the processor;

[0035] The processor is configured to perform the test method for surrounding rock deformation and support structure stress as described in the first aspect above.

[0036] Thirdly, embodiments of the present invention provide a storage medium storing computer instructions thereon, which, when executed by a processor, implement the rock deformation and support structure stress test method described in the first aspect above.

[0037] Compared with the prior art, the beneficial effects of the embodiments of the present invention include at least the following:

[0038] The test method for surrounding rock deformation and support structure stress provided by this invention solves the technical problems of existing in-situ tunnel testing technology, such as difficulty in achieving controllable deformation, incomplete data collection, and insufficient reliability of test results, through a systematic test process and scientific test methods. It provides effective technical support for the safe construction and long-term stability control of deeply buried soft rock tunnels. Attached Figure Description

[0039] Figure 1 A flowchart of the test method for surrounding rock deformation and support structure stress provided in the embodiments of the present invention;

[0040] Figure 2 This is a schematic diagram of the in-situ testing device provided in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the control structure of an electronic device provided in an embodiment of the present invention.

[0042] In the diagram: 1-Reaction frame; 2-Loading mechanism; 21-Loading cylinder; 22-Circular arc pressure plate. Detailed Implementation

[0043] 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 a part of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Figure 1 A flowchart of the test method for surrounding rock deformation and support structure stress provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the in-situ testing device provided in an embodiment of the present invention. Figures 1 to 2As shown in the figure, this invention provides a method for testing the deformation of surrounding rock and the stress on the support structure. This method is implemented based on an in-situ testing device. Through a systematic testing process, it can accurately obtain the relationship between the deformation of the surrounding rock and the stress on the support structure under controllable conditions. The following is a detailed description of each step of the method.

[0045] S1: Set up an in-situ test device inside the test tunnel.

[0046] This step is the preliminary preparation stage of the entire experiment, including the transportation, installation, and commissioning of the equipment.

[0047] First, forklifts or overhead cranes are used to move the various components of the device from the tunnel entrance to the designated test location inside the test tunnel. Due to the limited space and narrow passages in the deeply buried tunnel, the device adopts a segmented design, allowing each component to be transported separately. Inside the test tunnel, forklifts are used to unload heavy components, and a safe working area is designated and lighting lines are installed to create a safe working environment for subsequent installation work.

[0048] The installation of the device follows the principle of "from the center outwards, from the main frame to the additional components", and each component is installed in sequence from bottom to top and from inside to outside.

[0049] An in-situ testing device is installed inside the test tunnel. The device includes a ring-shaped reaction frame 1 and multiple loading mechanisms 2 arranged at equal angular intervals around the outer ring of the reaction frame 1. In this embodiment, eight loading mechanisms 2 are evenly arranged at 45° intervals along the circumferential direction. Each loading mechanism 2 includes a loading cylinder 21 and an arc-shaped pressure plate 22. The loading cylinder 21 is connected to the reaction frame 1, and its output end is arranged radially outward along the reaction frame 1. The arc-shaped pressure plate 22 is connected to the output end and abuts against the surrounding rock of the tunnel.

[0050] During installation, the loading mechanism 2 is first installed at the bottom of the tunnel. This involves laying the arc-shaped pressure plate 22 first, followed by the installation of the reaction frame 1. The reaction frame 1 can be pre-supported and connected to the arc-shaped pressure plate 22 via a matching guide rod structure. Next, the hydraulic loading system is installed, with eight loading cylinders 21 arranged radially in a circumferential direction. Their lower ends are connected to the reaction frame 1, and their retractable output ends are connected to the arc-shaped pressure plate 22, and then connected to the servo controller via pressure pipelines. Finally, a data acquisition system is installed, including force sensors and displacement sensors. The force sensors are used to measure the actual test force applied by the loading cylinders 21 in real time, and the displacement sensors are used to synchronously monitor the displacement values ​​at the output ends.

[0051] After the device installation is completed, a pre-load test is conducted. The servo controller controls the loading cylinder 21 to pre-load at 5%-10% of its maximum output of 150T, meaning each loading cylinder 21 applies a pre-load force of 7.5T to 15T. The purpose of the pre-load test is to ensure good initial contact between the retractable ring structure and the surrounding rock, and to ensure that each arc-shaped pressure plate 22 fully adheres to the rock surface, eliminating initial gaps. Simultaneously, it checks the signals of the hydraulic loading system and data acquisition system to ensure they are normal, and verifies the working status of each sensor.

[0052] The technical benefits of this step are as follows: through standardized transportation and installation procedures, the in-situ testing device can be correctly installed and in good working condition within the test tunnel; through pre-pressure testing, potential installation problems can be identified and resolved in advance, laying the foundation for the smooth conduct of subsequent tests.

[0053] S2: Continue excavating the test tunnel and monitor the response load and displacement of the surrounding rock of the tunnel on the circular arc pressure plate 22.

[0054] After the installation and commissioning of the equipment are completed, the segment bearing capacity testing phase begins, namely the load response test for limited displacement monitoring. This step simulates the development law of surrounding rock pressure under rigid support conditions during tunnel excavation.

[0055] Before the formal start of the experiment, environmental monitoring and system calibration were conducted. The temperature and humidity of the test area were continuously monitored. The environment was considered stable when the temperature change was ≤±1℃ and the humidity change was ≤±5%. After environmental stability, the loading mechanism 2 was calibrated using a servo controller: the loading cylinder 21 was pre-loaded at 5%-10% of its maximum output to verify the detection accuracy of the force and displacement sensors. By comparing with theoretical values, it was confirmed that the sensor measurement accuracy met the experimental requirements.

[0056] After environmental monitoring and system calibration were completed, the test tunnel continued to be excavated. During the excavation process, the displacement of the expandable circular ring structure was kept constant by a servo controller, that is, the position of the arc-shaped pressure plate 22 was kept fixed to simulate the effect of a rigid support structure. As the tunnel face advanced, the stress of the surrounding rock redistributed, and the load acting on the arc-shaped pressure plate 22 gradually increased.

[0057] Specifically, a force sensor is used to measure in real time the actual test force applied by the loading cylinder 21, which is the response load of the surrounding rock acting on the arc-shaped pressure plate 22. A displacement sensor is used to synchronously monitor the displacement value at the output end. Although the control displacement remains constant during this stage, real-time monitoring of the displacement data can verify the effectiveness of the displacement control and ensure that the arc-shaped pressure plate 22 is indeed kept in the set position.

[0058] During the monitoring process, the data acquisition system automatically collects data at preset time intervals. In the initial stage of the first time period, the data acquisition interval of the force sensor and displacement sensor is ≤5 minutes to capture the rapid phase of load change; in the later stage of the second time period after the first time period, the data acquisition interval of the force sensor and displacement sensor is ≤30 minutes to continuously monitor the slow change process of the load.

[0059] Based on the collected data, load-tunneling distance curves and load-time curves were plotted. The load-tunneling distance curve reflects the variation of the load on the support structure caused by the surrounding rock as the tunnel face advances; the load-time curve reflects the evolution of the surrounding rock pressure over time at a fixed tunneling position.

[0060] When the difference between the current response load of the circular arc pressure plate 22 and the response load 24 hours ago is ≤ 5% of the response load value collected 24 hours ago, the load is considered stable and this step is stopped. This criterion takes into account the rheological characteristics of the surrounding rock, ensuring that the stress in the surrounding rock has tended to a stable state. When the load stability condition is met, the monitoring of this step is stopped, marking the completion of the segment bearing capacity test phase.

[0061] The technical benefits of this step are as follows: by monitoring the load response under restricted displacement, the load response of the surrounding rock during excavation and the initial stabilization of the support structure can be accurately obtained, truly reflecting the development law of surrounding rock pressure under rigid support conditions. The obtained load-tunneling distance curves and load-time curves reveal the variation law between surrounding rock deformation and support structure stress at different distances from the tunnel face, providing important experimental data for understanding the interaction mechanism between surrounding rock and support.

[0062] S3: Set multiple displacement levels, control the extension and retraction of the output end of the loading cylinder 21 to apply displacement to the arc pressure plate 22, and monitor the response load under different displacement levels.

[0063] This step leads to the deformation-controlled constraint test stage, namely the multi-level restricted displacement monitoring load response test. In this stage, the synergistic effect of the surrounding rock and support structure is simulated under different pre-set deformation conditions by actively controlling the displacement of the support structure.

[0064] First, set multiple displacement levels. Based on the reference device's expandable range and the expected deformation value of the surrounding rock in the test tunnel, set multiple displacement levels ui. Typically, these are divided into 10 to 15 levels, each within 5% of the deformation value. The setting of multiple displacement levels should follow the principle of gradual increase from small to large to ensure the continuity of the test process and the comparability of the data. The set displacement sequence is denoted as u1, u2, u3, ..., un, where n is the number of levels (10-15).

[0065] For example, if the maximum expected deformation of the surrounding rock is 200 mm, it can be divided into 10 levels, with each level having a displacement of 20 mm; or into 15 levels, with each level having a displacement of approximately 13.3 mm.

[0066] After outputting the displacement at each level, the support force of the arc-shaped pressure plate 22 is immediately collected by a force sensor. The output of each loading cylinder 21 is individually controlled by a servo controller, driving the telescopic ring structure to extend or retract, causing the arc-shaped pressure plate 22 to contract or extend from its current position, applying the displacement ui. In this embodiment, due to the inward deformation of the surrounding rock, the arc-shaped pressure plate 22 needs to contract inward to simulate different support dimensions, i.e., to reserve different deformation spaces.

[0067] Immediately after applying the displacement ui, the support force Pi of the arc-shaped pressure plate 22 is collected via a force sensor. The support force Pi at this point reflects the initial load response of the surrounding rock under the constraint of the displacement ui. Due to the time-dependent and rheological properties of the surrounding rock, the support force changes over time. Therefore, the support force is collected again after 10 minutes. This design considers the time effect of surrounding rock stress adjustment; by comparing the two collected values, it can be determined whether the surrounding rock stress tends to stabilize.

[0068] When the ratio of the difference between two adjacent support force acquisition values ​​to the difference between the first acquisition value under the same displacement level and the last acquisition value under the previous displacement level is less than 5%, the next level of displacement will be output.

[0069] Specifically, let the support force of the first sampling be P. i，1 The support force measured 10 minutes later was P. i，2 The support force collected in the last sampling at the previous level ui-1 was P. i-1，last Calculate the difference P between two consecutive data collections. i，2 -P i，1 The difference P between the first collected value under the same level UI and the last collected value under the previous level UI-1 i，1 -P i-1，last The ratio:

[0070] Ratio = (P) i，2 -P i，1 ) / (P i，1 -P i-1，last )

[0071] When this ratio is less than 5%, it is considered that the surrounding rock stress has stabilized under the displacement ui, and the next displacement ui+1 can be applied. This criterion comprehensively considers two factors: one is the rate of change of load P under the current displacement. i，2 -P i，1 Secondly, the load increment P caused by the current displacement. i，1 -Pi-1，last When the rate of change of load is sufficiently small relative to the load increment, it indicates that the stress adjustment of the surrounding rock has been basically completed.

[0072] Repeat the aforementioned steps to plot the stress-displacement curve and save the data. Once the stability criteria are met, record the test data for the current stage, including the displacement ui and the corresponding stabilizing support force P. i，2 Then, the servo controller controls the loading cylinder 21 to continue extending and retracting, applying the next level of displacement ui+1. This process of graded displacement loading and stability determination is repeated until all preset displacement levels are completed.

[0073] Throughout the graded displacement loading process, the data acquisition system stores all acquired data in real time through the storage module, including the displacement ui for each grade, the corresponding support force Pi, and time information. After the test, a stress-displacement curve is plotted based on the stored data, with the horizontal axis representing the displacement and the vertical axis representing the support force or stress-support force divided by the loading area.

[0074] The technical benefits of this step are as follows: Through deformation-controlled constraint tests, the load response of the support structure under different displacement allowances can be obtained, revealing the quantitative relationship between the deformation of the surrounding rock and the stress on the support structure. The plotted stress-displacement curves can reflect the deformation characteristics of the surrounding rock and the bearing capacity of the support structure, providing a scientific basis for optimizing support design and determining reasonable allowance deformations. Simultaneously, this active displacement control test method overcomes the limitations of traditional passive loading tests, enabling a more realistic simulation of the construction process in actual engineering where surrounding rock deformation is controlled by adjusting support stiffness.

[0075] S4: The loading cylinder 21 is controlled to apply load and unload in stages according to the predetermined load levels, and a cyclic loading and unloading test is carried out to monitor the rebound displacement of the surrounding rock of the tunnel.

[0076] This step includes three sub-stages: active loading test, active unloading test, and cyclic loading and unloading test, which together constitute the active loading and unloading and cyclic test stage.

[0077] S41. Active loading test.

[0078] The load is divided into 10 to 15 levels, each 1.2 times the engineering design pressure, and the loading cylinder 21 applies the load level by level. The engineering design pressure refers to the expected maximum surrounding rock pressure determined based on the in-situ stress level of the strata where the tunnel is located and the support design. Taking 1.2 times the engineering design pressure as the maximum applied load is to account for a certain safety factor and to verify the bearing capacity and deformation characteristics of the support structure under the over-design load.

[0079] For example, if the engineering design pressure is 1.0 MPa, then the maximum applied load is 1.2 MPa. The maximum total load can be calculated based on the loading area of ​​the device. Dividing it into 10 equal levels, each level has a corresponding load increment; dividing it into 15 equal levels, the load increment for each level decreases accordingly. The load classification sequence is denoted as F1, F2, F3, ..., F... m , where m is the number of levels, 10-15.

[0080] When the loading cylinder 21 applies a load, the loading cylinders 21 in multiple loading mechanisms 2 apply the load synchronously and uniformly, with each loading cylinder 21 having a maximum output of 150T. The loading cylinders 21 are controlled by a servo controller to apply the load in stages. During load application, it is ensured that the load is applied consistently in all directions to avoid eccentric loading. The servo controller precisely adjusts the output of each loading cylinder 21 to achieve the preset load value.

[0081] In this embodiment, when all eight loading cylinders 21 operate simultaneously, the total loading capacity of the device is 1200T, which is sufficient to meet the test requirements. The servo controller can realize the load loading mode, that is, based on the feedback signal of the force sensor, it automatically adjusts the pressure of the hydraulic system to keep the actual output force of the loading cylinders 21 at the set value and maintain a constant load for a long time.

[0082] Immediately after each load level is applied, the detection data from the force sensor and displacement sensor are collected, and the data is collected again after 10 minutes. Once the load stability condition is met, the next load level is applied. The relationship between the support force and the deformation of the tunnel surrounding rock is recorded, and the load-displacement curve is plotted.

[0083] A force sensor measures the actual load applied by the loading cylinder 21, and a displacement sensor measures the deformation of the surrounding rock caused by the outward pushing of the arc-shaped pressure plate 22. The load stability criterion is: when the difference between two adjacent load values ​​is less than or equal to a certain percentage (e.g., 5%) of the set load value, and the displacement change rate is sufficiently small, the load is considered stable. After the load stability condition is met, the test data for the current stage is recorded, including the load value, the corresponding surrounding rock deformation, and time information, before proceeding to the next stage of load application.

[0084] Throughout the loading process, the relationship between the support force (i.e., the load applied by the loading cylinder 21) and the surrounding rock deformation (i.e., the displacement measured by the displacement sensor) was recorded, and a load-displacement curve was plotted. The horizontal axis of the curve represents the surrounding rock deformation, and the vertical axis represents the applied load, reflecting the deformation response characteristics of the surrounding rock under active loading conditions.

[0085] During the loading process, the safety protection module of the hydraulic loading system monitors the stability of the device in real time. The servo controller continuously monitors the working status of each loading cylinder 21. If an abnormality is detected in the working status of the loading cylinder 21 in different positions, it indicates that the device may be experiencing eccentric pressure or local instability. The servo controller will automatically adjust the output of each loading cylinder 21 to correct the deviation, or trigger emergency braking in severe cases to immediately stop loading and maintain the current state, protecting the safety of the device and the test personnel.

[0086] S42. Active unloading test.

[0087] The applied load is divided into 10 to 15 levels, with the loading cylinder 21 controlling the pressure release step by step. The number of unloading levels is usually consistent with the number of loading levels to facilitate comparative analysis of the differences in surrounding rock deformation during loading and unloading. The unloading load sequence is F. m F m-1 F m-2 F1, 0, means gradually unloading from the maximum load to zero load.

[0088] The loading cylinders 21 are depressurized in stages by a servo controller. The servo controller individually adjusts the depressurization intensity of each group of loading cylinders 21, reducing their output from the load value of the current stage to the load value of the next stage. During the unloading process, due to the elastic recovery and plastic deformation of the surrounding rock, the arc-shaped pressure plate 22 will generate a rebound displacement. The displacement sensor monitors the rebound displacement of the surrounding rock in real time, and this displacement reflects the amount of elastic deformation of the surrounding rock.

[0089] Immediately after each load is depressurized, the detection data from the force sensor and displacement sensor are collected, and the data is collected again after 10 minutes. When the judgment condition of load stability is met, the next load depressurization is initiated. The relationship between the support force and the deformation of the tunnel surrounding rock is recorded and the load-displacement curve is plotted.

[0090] The stability determination criteria are similar to those of the loading process: when the difference between two adjacent load values ​​and the rate of displacement change meet the stability criteria, the current unloading stage is determined to be stable, the test data is recorded, and the next stage of load unloading begins.

[0091] Record the relationship between the support force and the deformation of the surrounding rock during the unloading process, and plot the load-displacement curve for the unloading stage. By superimposing the unloading curve with the loading curve, the loading-unloading hysteresis loop can be observed. The area of ​​the hysteresis loop reflects the energy dissipation of the surrounding rock during the loading-unloading cycle, and the shape of the hysteresis loop reflects the elastoplastic properties of the surrounding rock.

[0092] S43. Cyclic loading and unloading test.

[0093] The loading cylinder 21 is cyclically applied and depressurized in stages for 2 to 3 rounds. The load-displacement curves in each round are continuously monitored, and the plastic deformation characteristics of the tunnel surrounding rock are analyzed based on the load-displacement curves.

[0094] Each cycle was conducted according to the same load grade to ensure consistency of test conditions. After the first cycle, the surrounding rock underwent a complete loading-unloading process, and some plastic deformation had occurred; changes in the deformation behavior of the surrounding rock could be observed in the second and third cycles.

[0095] The data acquisition system continuously monitors and stores the load-displacement curves for each cycle. By comparing the curves from different cycles, it can be observed that: during the initial loading, the surrounding rock undergoes significant plastic deformation, and residual deformation is evident after unloading; in subsequent cycles, the proportion of elastic deformation of the surrounding rock increases, and the hysteresis loop area decreases, indicating that the surrounding rock gradually tends towards a stable state.

[0096] Based on the load-displacement hysteresis curves of each cycle, the plastic deformation characteristics of the tunnel surrounding rock are analyzed, including:

[0097] Plastic strain accumulation: The cumulative plastic strain of the surrounding rock is calculated by using the residual deformation after each unloading cycle, and the long-term deformation potential of the surrounding rock is assessed.

[0098] Stiffness degradation: By comparing the slopes of the loading curves for each cycle, the variation law of the surrounding rock stiffness with the number of cycles is analyzed, and the damage evolution process of the surrounding rock is evaluated.

[0099] Energy dissipation: Calculate the area of ​​the hysteresis loop in each cycle, analyze the energy dissipation characteristics of the surrounding rock under cyclic loading, and evaluate the damping performance of the surrounding rock.

[0100] Fatigue characteristics: The fatigue characteristics of the surrounding rock under repeated loading are evaluated through multiple rounds of cyclic tests, providing a basis for long-term stability analysis.

[0101] The technical benefits of this step are as follows: Through active loading and unloading and cyclic tests, the relationship between displacement and stress in the surrounding rock under different stress paths can be obtained. Active loading tests can evaluate the bearing capacity and deformation characteristics of the support structure under design loads and over-design loads; active unloading tests can distinguish between elastic and plastic deformation in the surrounding rock, providing key parameters for establishing a constitutive model of the surrounding rock; cyclic loading and unloading tests can reveal the mechanical behavior of the surrounding rock under repeated loading, including plastic strain accumulation, stiffness degradation, and energy dissipation, providing important evidence for evaluating the long-term stability and seismic performance of the tunnel. These experimental data are of great value for inverting rock mass mechanical parameters, establishing a constitutive model of the surrounding rock, and optimizing support design.

[0102] S5: Disassemble the in-situ test device in reverse order.

[0103] After the test is completed, the in-situ test equipment needs to be disassembled so that it can be moved to the next test location or transported out of the tunnel.

[0104] First, protective covers should be installed on the force sensors, displacement sensors, and other monitoring instruments in the data acquisition system. These precision sensors are easily damaged by impacts and contamination during disassembly and transportation. Installing protective covers can effectively protect the sensors, extend their service life, and ensure that they can still provide accurate measurement data in subsequent tests.

[0105] Then, following the reverse order of installation, disassemble the device components sequentially from top to bottom and from outside to inside. The specific disassembly sequence is as follows: First, disassemble the hydraulic loading system, disconnect the loading cylinder 21 from the hydraulic system, and remove the pressure pipeline. Then, remove the loading cylinder 21 from the reaction frame 1 and the arc-shaped pressure plate 22. Next, disassemble the reaction frame 1 and disconnect all connections. Finally, disassemble the retractable ring structure, and disassemble each component in sequence. During disassembly, follow the numbered order and label each component for future installation.

[0106] After disassembly, clean each component, removing surface dirt and rock debris. Inspect each component for damage or deformation, and repair or replace severely worn parts. Maintain the hydraulic system, check the hydraulic oil quality, and replace it if necessary. Calibrate and check the sensors to ensure their measurement accuracy meets requirements.

[0107] After cleaning and maintenance, properly store or transfer all components of the device to the next testing location. Use specialized packaging and transport vehicles to ensure the device is not damaged during storage and transportation.

[0108] The technical benefits of this step are: through standardized disassembly procedures and proper maintenance, the service life of the device is extended, ensuring that the device can be reused at multiple test sites, thus improving the device's economy and practicality.

[0109] The method for testing the deformation of surrounding rock and the stress of support structures provided in this invention has the following comprehensive technical advantages:

[0110] 1. Realistic simulation of the interaction between surrounding rock and support: Through step 2 of the segment bearing characteristics test, the development process of surrounding rock pressure during tunnel excavation can be realistically simulated, and the variation law between surrounding rock deformation and support structure stress at different distances from the tunnel face can be obtained.

[0111] 2. Achieving tests under controllable deformation conditions: Step 3 of the controllable deformation constraint test overcomes the limitations of traditional passive loading tests, enabling active control of the displacement of the support structure and simulating the synergistic effect of surrounding rock and support under different reserved deformation conditions, providing a scientific basis for optimizing support design.

[0112] 3. Obtaining the elastic-plastic mechanical parameters of the surrounding rock: Through active loading and unloading and cyclic testing step 4, it is possible to distinguish between elastic deformation and plastic deformation in the surrounding rock deformation, revealing the elastic-plastic characteristics, stiffness degradation law, energy dissipation characteristics, etc. of the surrounding rock, providing sufficient experimental data for establishing an accurate constitutive model of the surrounding rock and inverting real and reliable rock mass mechanical parameters.

[0113] 4. Multi-scale and multi-parameter collaborative monitoring: Through the supporting data acquisition system, multiple parameters such as load, displacement, and time can be monitored simultaneously to obtain the variation law of surrounding rock and support structure under the influence of four dimensions of time and space, providing comprehensive experimental data for a deeper understanding of the interaction mechanism between surrounding rock and support.

[0114] 5. Provide reference for engineering design and construction: The test data and analysis results obtained by the method of this invention can provide a reference for the support design during and after the tunnel excavation process, guide the determination of the reserved deformation amount, the selection of the support timing, and the optimization of support parameters, thereby improving the safety and economy of tunnel construction and ensuring the long-term stable operation of the tunnel.

[0115] In summary, the test method for surrounding rock deformation and support structure stress provided by this invention solves the technical problems of existing in-situ tunnel testing techniques, such as difficulty in achieving controllable deformation, incomplete data collection, and insufficient reliability of test results, through a systematic test process and scientific test methods. It provides effective technical support for the safe construction and long-term stability control of deeply buried soft rock tunnels.

[0116] Figure 3 This is a schematic diagram of the control structure of an electronic device provided in an embodiment of the present invention. Figure 3 As shown, the electronic device includes a processor and a memory for storing processor-executable instructions. The electronic device 3100 can be a computer device, and the electronic device 3100 may include one or more of the following components: processor 3101, memory 3102, communication interface 3103, and bus 3104.

[0117] The processor 3101 includes one or more processing cores. The processor 3101 executes various functional applications and information processing by running software programs and modules. The memory 3102 and the communication interface 3103 are connected to the processor 3101 via a bus 3104. The memory 3102 can be used to store at least one instruction, which the processor 3101 uses to execute to implement the steps S2 to S4 in the above method embodiments.

[0118] Furthermore, memory 3102 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: magnetic disks or optical disks, electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), read-only memory (ROM), magnetic storage, flash memory, and programmable read-only memory (PROM).

[0119] For example, in this embodiment of the invention, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory including instructions, which can be executed by a processor in steps S2 to S4 of the aforementioned test method for surrounding rock deformation and support structure stress. For example, the non-transitory computer-readable storage medium may be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0120] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0121] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0122] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0123] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for testing the deformation of surrounding rock and the stress of support structures, characterized in that, include: Step 1: Set up an in-situ test device in the test tunnel. The in-situ test device includes a ring-shaped reaction frame (1) and multiple loading mechanisms (2) arranged at equal angles on the outer ring of the reaction frame (1). The loading mechanism (2) includes a loading cylinder (21) and an arc plate (22). The loading cylinder (21) is connected to the reaction frame (1) and its output end is arranged radially outward along the reaction frame (1). The arc plate (22) is connected to the output end and abuts against the surrounding rock of the tunnel. Step 2: Continue excavating the test tunnel and monitor the response load of the surrounding rock of the tunnel on the circular arc pressure plate (22) and the displacement of the circular arc pressure plate (22), including: During the excavation process, the position of the arc-shaped pressure plate (22) is kept fixed by a servo controller to simulate the function of a rigid support structure; The test force actually applied by the loading cylinder (21) is measured in real time using a force sensor. The test force is the response load of the surrounding rock on the arc pressure plate (22). The displacement value of the output end is monitored synchronously using a displacement sensor. During the first time period, the data acquisition interval of the force sensor and the displacement sensor is ≤5 minutes. During the second time period after the first time period, the data acquisition interval of the force sensor and the displacement sensor is ≤30 minutes. Based on the acquired data, load-tunneling distance curve and load-time curve are plotted. When the difference between the current response load of the arc plate (22) and the response load 24 hours ago is ≤5% of the response load acquired 24 hours ago, the load is determined to be stable and the step is stopped. Step 3: Set multi-level displacement amounts, control the extension and retraction of the output end of the loading cylinder (21) to apply displacement to the arc plate (22), monitor the response load of the arc plate (22) under different displacement amounts, simulate the synergistic effect of surrounding rock and support under different reserved deformation conditions. Due to the inward deformation of the surrounding rock, the arc plate (22) contracts inward to simulate different support dimensions, that is, to reserve different deformation spaces, including: After outputting the displacement at each level, the support force of the arc plate (22) is immediately collected by the force sensor, and collected again after 10 minutes; When the difference between two consecutive support force acquisition values ​​is less than 5% of the ratio of the first acquisition value under the same displacement level and the last acquisition value under the previous displacement level, the next level of displacement is output. Repeat the above steps to plot the stress-displacement curve and save the data; Step 4: Control the loading cylinder (21) to apply load and unload in stages according to the predetermined load levels, and conduct cyclic loading and unloading tests to monitor the rebound displacement of the surrounding rock of the tunnel; Step 5: Disassemble the in-situ test device in reverse order.

2. The method for testing the deformation of surrounding rock and the stress of support structures according to claim 1, characterized in that, The steps preceding step 2 also include: The temperature and humidity of the test area are continuously monitored. When the temperature change is ≤ ±1℃ and the humidity change is ≤ ±5%, the loading mechanism (2) is calibrated by the servo controller. Control the loading cylinder (21) to preload at 5%-10% of its maximum output to verify the detection accuracy of the force sensor and the displacement sensor.

3. The method for testing the deformation of surrounding rock and the stress of support structures according to claim 1, characterized in that, Step 4 includes: The load is divided into 10 to 15 levels according to 1.2 times the engineering design pressure, and the loading cylinder (21) is controlled to apply the load level by level. Immediately after each load level is applied, the detection data from the force sensor and the displacement sensor are collected, and the data is collected again after 10 minutes. When the load stability judgment condition is met, the next load level is applied. The relationship between the support force and the deformation of the tunnel surrounding rock is recorded and the load-displacement curve is plotted.

4. The method for testing the deformation of surrounding rock and the stress of support structures according to claim 3, characterized in that, When the loading cylinder (21) applies a load, the loading cylinders (21) in the multiple loading mechanisms (2) are loaded synchronously and uniformly, and the maximum output of each loading cylinder (21) is 150T.

5. The method for testing the deformation of surrounding rock and the stress of support structures according to claim 3, characterized in that, Step 4 also includes: The loading cylinder (21) is controlled to depressurize step by step according to the maximum value of the applied load, which is divided into 10 to 15 levels. Immediately after each load is depressurized, the detection data of the force sensor and the displacement sensor are collected, and the data is collected again after 10 minutes. When the judgment condition of load stability is met, the next load depressurization is carried out. The relationship between the support force and the deformation of the tunnel surrounding rock is recorded and the load-displacement curve is plotted.

6. The method for testing the deformation of surrounding rock and the stress of support structures according to claim 5, characterized in that, Step 4 also includes: The loading cylinder (21) is cyclically applied and depressurized in stages for 2 to 3 rounds, and the load-displacement curves in each round are continuously detected. The plastic deformation characteristics of the tunnel surrounding rock are analyzed based on the load-displacement curves.

7. An electronic device, characterized in that, include: processor; Memory used to store instructions that can be executed by the processor; The processor is configured to perform the test method for surrounding rock deformation and support structure stress as described in any one of claims 1 to 6.

8. A storage medium storing computer instructions thereon, characterized in that, When the computer instructions are executed by the processor, they implement the test method for surrounding rock deformation and support structure stress as described in any one of claims 1 to 6.

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