A shaking table test method considering time-varying deterioration of seismic performance of anchored rock slope

Abstract

The present application belongs to the field of geotechnical engineering disaster prevention and mitigation and earthquake engineering test technology, and relates to a shaking table test method considering time-varying degradation of seismic performance of anchored rock slope. The method first constructs a dynamic performance time-varying degradation model based on the attenuation law of the interface bonding force of the anchoring system and the yield resistance of the free section reinforcement; by adjusting the proportion of the rock similar material and using a staged stiffness anchoring system, the physical equivalent simulation of interface degradation and component yield resistance reduction is realized respectively. The core of the present application is that before the shaking table applies the seismic wave, the anchoring performance degradation of the supporting structure is simulated actively in advance, so as to reproduce the real evolution path that the bearing capacity of the anchoring system decreases first, leading to stress redistribution and cumulative damage of the slope, and then suffering from sudden seismic load, breaking through the limitation of traditional test which only simply simulates static low bearing capacity. The present application effectively realizes the space-time coupling of "static time-varying degradation accumulation" and "instantaneous seismic dynamic action", solves the problem of simulation distortion of interface degradation, and provides a reliable test method for dynamic stability evaluation and reinforcement design of long-term service anchored slope.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering disaster prevention and mitigation and earthquake engineering testing technology, specifically relating to a shaking table test method that takes into account the time-varying deterioration of the seismic performance of anchored rock slopes. Background Technology

[0002] In the fields of geotechnical engineering and earthquake engineering, prestressed anchor cables are widely used as a key support method for high and steep rock slopes, in major projects such as high slopes of large hydropower stations, sidewalls of traffic tunnels, and deep open-pit mines. However, over a service life of several decades, such slopes are inevitably affected by a combination of factors such as rock creep, anchor loosening, grout aging, and metal corrosion, leading to the deterioration of the mechanical properties of the anchoring system.

[0003] Current rock slope shaking table tests mostly assume that the anchoring system's bearing capacity is at its initial design state or a constant low value, neglecting the actual path of anchoring performance degradation after years of service. In fact, research on the seismic performance of existing slopes is not merely about exploring the response under "low bearing capacity," but more importantly, about revealing the failure mechanism under the actual service path of "first, the dynamic performance of the anchoring system deteriorates, leading to stress redistribution and initial damage, followed by sudden seismic loading." Slopes in a "sub-healthy" state, with their accumulated microcracks and stress concentration, will significantly alter the subsequent seismic dynamic propagation characteristics.

[0004] Some technologies have been developed to address these issues, but limitations remain.

[0005] (1) Although CN110747912A has achieved synchronous monitoring of anchorage force loss and deformation, it is limited to quasi-static loading and lacks response research under seismic dynamic action;

[0006] (2) CN109883675A focuses on the environmental corrosion durability at the micro level of the material and fails to dynamically couple the material degradation caused by the service life with the overall seismic dynamic loading of the structure.

[0007] (3) CN113670723A realized the observation of slope earthquake damage, but did not set up a module to reflect the time-varying characteristics of anchorage, and ignored the change of the initial stress state of the slope.

[0008] (4) Although CN113639948B has established a numerical simulation model, it lacks verification by physical entity tests and is difficult to realistically simulate the complex nonlinear physical slip and biting effects of the anchoring interface.

[0009] In summary, existing technologies have three main shortcomings: First, they lack physical simulation of the "deterioration before earthquake" path; second, material interface degradation and overall structural dynamic testing are disconnected; and third, the service age effect and seismic action are decoupled on the time axis. Specifically, existing scaled physical model tests cannot realistically reproduce the spatiotemporal coupling effect of "anchoring performance degradation caused by long-term service" and "transient seismic load," and in particular, they lack effective means to finely simulate the multi-interface coupling degradation of mortar-rock interface bond force, anchor-mortar interface bond force, and free section steel yield resistance in the anchoring system.

[0010] Therefore, in order to address the life-cycle safety research issues of complex projects such as hydropower projects, transportation arteries, and open-pit mines of the Three Gorges Group, it is necessary to develop a quantifiable and verifiable shaking table test method that can realistically reproduce the full-process response characteristics of slopes under different service ages of "cumulative static damage - dynamic seismic triggering". Summary of the Invention

[0011] To address the problems of simplified anchorage degradation mechanisms and failure to accurately reflect the coupling effect of dynamic performance degradation and seismic loading in existing shaking table tests for rock anchored slopes, this invention proposes a shaking table test method that considers the time-varying degradation of the seismic performance of anchored rock slopes. This method aims to overcome the limitations of traditional tests that only focus on static, constant low-bearing-capacity states. Its core is to reproduce the actual evolution path of "first, a decrease in the bearing capacity of the anchorage system leading to stress redistribution and cumulative damage within the slope, followed by a sudden seismic load," thereby achieving a refined physical simulation of the progressive failure process of rock anchored slopes under the coupling effect of dynamic performance degradation and seismic loading.

[0012] This method mainly includes the following technical steps:

[0013] S1. Constructing a comprehensive test system and preparing a physical model: A test platform consisting of a shaking table main unit, a model box, an adjustable anchoring loading system, and a multi-parameter synchronous monitoring system is built. A scaled-down rock slope is constructed within the model box, and an anchoring system is installed to form a test slope model.

[0014] A comprehensive test platform was established, consisting of a shaking table main unit, a model box, an adjustable anchoring loading system, rock mass similar materials, and a multi-parameter synchronous monitoring system. Based on the similarity theorem, the geometric dimensions and physical and mechanical parameter ratios of the model were determined. A scaled-down rock slope was constructed within the model box, and the anchoring system was arranged according to a pre-set scheme to build a scaled-down model representing a steep rock anchored slope. The specific functions and configurations of each component of the comprehensive test system are as follows:

[0015] Shaking table main unit: used to input multidimensional seismic wave loads into the model box and slope model to simulate the triggering environment of ground motions of different intensities;

[0016] Model box: Fixedly installed on the vibration table, used to fill the rock slope model and provide boundary constraints;

[0017] Adjustable anchoring loading system: set on the slope model, used to apply initial design prestress to the model anchor cables, and has an active axial force adjustment function. By adjusting the state of the mechanical components, it can be used in conjunction with the subsequent test step S3 to simulate the degradation of the yield resistance of the free section steel bars.

[0018] Rock mass similar material: used to formulate soil-rock mixtures with different mix proportions according to the linear regression equation, in order to simulate the mechanical property decay of bedrock, structural planes and mortar-rock interface under different service ages, and to achieve physical simulation of interfacial bonding force in conjunction with step S3;

[0019] Multi-parameter synchronous monitoring system: including accelerometer, miniature anchor cable axial force sensor, laser displacement sensor or wire displacement meter, miniature earth pressure cell and anchorage section strain gauge, used to collect stress redistribution data of slope during static deterioration process and dynamic response data during dynamic seismic loading process in real time.

[0020] S2. Construction of a Time-Varying Deterioration Model for the Dynamic Performance of the Anchoring System: Based on the failure mechanism of the anchoring system, the time-varying expression forms of the mortar-rock interface bond force, the anchor-mortar interface bond force, and the yield resistance of the free section of the anchor cable are determined, and the minimum value among the three is taken as the time-varying bearing capacity of the anchoring system.

[0021] Define the time-varying functions of three types of interfaces and components in the anchoring system: mortar-rock interface bond strength. Anchor bolt-mortar interface adhesion Yield resistance of free section reinforcement The time-varying bearing capacity is determined by the minimum value of the three factors.

[0022] (1) Establish a time-varying model of anchor cable corrosion depth coupled with temperature and humidity:

[0023] An exponential sensitivity term for ambient temperature and relative humidity is introduced to construct a corrosion depth evolution model, which quantitatively characterizes the changes in corrosion rate caused by differences in service environment. (Corrosion Depth) (Unit: mm) Expressed in power law form:

[0024] {x}_{t}={k}_{0}exp\left [ {} \right ]\left ( {α\left ( {\frac {T-{T}_{0}} {{T}_{0}}} \right )+β\left ( {\frac {RH-{RH}_{o}} {{RH}_{0}}} \right )} \right ){t}^{n} ;

[0025] In the formula: The corrosion rate coefficient under standard conditions; These are the actual ambient temperature and relative humidity, respectively. These are the temperature and humidity of the standard reference environment, respectively; These are the sensitivity coefficients for temperature and humidity, respectively. Service life; This is a time exponent. This expression accurately reflects the slow corrosion characteristics of anchor cables under long-term environmental conditions.

[0026] (2) Determine the cross-sectional loss rate and mass corrosion ratio:

[0027] Based on the assumption of uniform corrosion of the circular cross-section of the reinforcing steel, according to the corrosion depth Constructing the corrosion rate of anchor cable cross-section :

[0028] ;

[0029] Further obtain the mass corrosion ratio :

[0030] .

[0031] (3) Calculate the time-varying values ​​of interfacial bonding properties:

[0032] Introducing an interface damage attenuation factor This is used to describe the decrease in interfacial bonding force caused by the expansion of corrosion products:

[0033] λ\left ( {t} \right )=kexp\left [ {-γ{β\left ( {t} \right )}^{p}} \right ] ;

[0034] In the formula: Used to characterize the initial integrity of the interface; Describe the sensitivity of interfacial strength to corrosion.

[0035] Based on this, the time-varying adhesive forces of the two types of interfaces are calculated respectively:

[0036] Calculate the time-varying value of the mortar-rock interface bond strength:

[0037] ;

[0038] Calculate the time-varying value of the bond resistance at the anchor bolt-mortar interface:

[0039] ;

[0040] In the formula: The borehole diameter; The length of the anchorage section; The initial shear strength of the mortar-rock interface; This represents the initial shear strength of the anchor bolt-mortar interface.

[0041] (4) Calculate the degradation and yield capacity of the reinforcing steel:

[0042] The yield strength degradation of steel bars is determined using an exponential material decay function:

[0043] Χ\left ( {t} \right )=exp\left [ {-δ{β\left ( {t} \right )}^{q}} \right ] ;

[0044] The effective yield strength of the steel bar after corrosion is thus obtained. :

[0045] ;

[0046] Considering the effective cross-sectional area caused by corrosion Calculate the nominal yield capacity of steel reinforcement :

[0047] ;

[0048] In the formula: The initial yield strength of the steel reinforcement; This represents the initial cross-sectional area of ​​the reinforcing bars; These are parameters related to material property degradation.

[0049] (5) Determine the time-varying bearing capacity of the anchoring system:

[0050] The time-varying bearing capacity of the anchorage system is controlled by the minimum value of the interfacial resistance and the yield bearing capacity of the steel reinforcement: T(t) = min[T_1(t),T_2(t),T_3(t)] .

[0051] Through the above model, this invention achieves a unified mathematical characterization of the corrosion depth development, interfacial bond strength degradation, and steel bar yield performance decay of prestressed anchor cables during long-term service, providing a quantitative theoretical basis for the subsequent physical reproduction of the time-varying safety of anchored structures in shaking table tests.

[0052] S3. Physical equivalent simulation of interface and component degradation: By combining interface degradation simulation and component degradation simulation, the process of dynamic performance degradation of the anchoring system over service time is equivalently reproduced in the test slope model.

[0053] Based on the model established in step S2, in order to realize the application of the above theoretical model in shaking table physical tests, this invention adopts a dual-channel system of "interface degradation simulation + component degradation simulation", including:

[0054] (I) Interface degradation simulation: By adjusting the mechanical parameters of similar materials to the rock mass, the constraint capacity of the rock mass medium on the anchoring system in the model changes with service time, thereby equivalently simulating the time-varying decay process of the mortar-rock interface bond force and the anchor bolt-mortar interface bond force. The specific steps include the following:

[0055] (1) Determine the time-dependent degradation target value of rock mass mechanical properties:

[0056] To facilitate the controllable reduction of rock mass mechanical parameters in the shaking table model, this study employs a unified time-dependent exponential decay model to describe the evolution of strength and stiffness. Let the instantaneous value of a certain mechanical parameter be... Its initial value is Long-term residual value Considering long-term loads, creep, and delayed failure effects, its time history can be described by a first-order exponential decay law:

[0057] ;

[0058] Degeneration factor ,have to

[0059] ;

[0060] In the formula: As a residual factor, The degradation rate; In months (or years) ,but ).

[0061] (2) Establish a regression model for the mix proportions and mechanical parameters of similar materials in rock masses:

[0062] In order to formulate rock mass similar materials that meet the above-mentioned "target mechanical parameter values", this invention establishes a quantitative relationship model between the physical and mechanical properties of rock mass similar materials and the main proportioning factors through multiple linear regression analysis:

[0063] A. Determine the main proportioning factors:

[0064] The mass ratio of weighting agent to aggregate The mass percentage of iron powder in the weighting agent gypsum content and glycerol content All the above factors are expressed as percentages;

[0065] B. Establish the regression equation:

[0066] Linear regression equation between density and various factors:

[0067]

[0068] The linear regression equation between cohesion and various factors is as follows:

[0069]

[0070] The linear regression equation between the internal friction angle and various factors is as follows:

[0071]

[0072] Linear regression equation between elastic modulus and various factors:

[0073]

[0074] In the formula: Units are ; Units are ; The unit is °; Units are ; to This represents the percentage content of the corresponding proportioning factor.

[0075] (3) Material formulation and interface degradation equivalence based on target value:

[0076] Based on the target mechanical parameter values ​​for a specific service life calculated in sub-step (1), and combined with the regression equation in sub-step (2), determine the parameters required to meet the target parameters. to Specific mix proportions; prepare rock mass similar materials according to this mix proportion. The strength reduction of this material is consistent with the theoretically calculated rock mass degradation law. Utilize the reduced constraint capacity of this weakened rock mass material on the anchoring system to equivalently simulate the gradual attenuation process of the mortar-rock interface bond force and the anchor bolt-mortar interface bond force as the service age increases, so that the interface shear bearing capacity is consistent with the interface degradation law in actual engineering.

[0077] (ii) Component degradation simulation: Different levels of initial prestress are applied to the anchor cable through an adjustable anchor loading system. A graded stiffness system composed of plastic-coated steel strand and Q235 steel sheet is used. By changing the steel sheet thickness, the length of the stressed section of the steel strand and the degree of nut tightening, the yield resistance of the steel bar in the free section of the anchor cable is set to multiple discrete levels according to the axial force calculated at different years. This is to simulate the phased decay of the bearing capacity of the free section with the service life caused by prestress relaxation, component corrosion and mechanical property deterioration.

[0078] S4. Perform a "stress redistribution-seismic coupling" loading test: After the bearing capacity of the anchoring system degrades and causes stress redistribution within the slope, apply seismic motion input to the test slope model and collect dynamic response data of the model to analyze the dynamic response characteristics of the slope under the coupling of time-varying deterioration of the anchoring system and seismic action.

[0079] This step strictly follows the timeline of "stress redistribution caused by the deterioration of the dynamic performance of the anchoring system first, followed by dynamic seismic loading," and conducts a full-process test on the model after step S3. The specific operation includes the following three stages:

[0080] (1) Static deterioration path simulation: When the main unit of the vibration table is stationary, the adjustable anchor loading system is used to actively adjust the mechanical parameters of the anchor cable according to the set working conditions, so that it deteriorates to a preset degree. During this process, the slope response is continuously monitored by the multi-parameter synchronous monitoring system until the monitoring data shows that the stress field redistribution process caused by the loss of the bearing capacity of the anchor system inside the slope is completed and the slope reaches a stable cumulative damage state.

[0081] (2) Dynamic seismic coupling loading: Taking the "stable cumulative damage state after static degradation" as the initial condition, start the shaking table host, and input the preset seismic motion time history into the model while keeping the interface degradation and component degradation simulation parameters unchanged;

[0082] Loading conditions: Input seismic waves of different waveforms into the model or input seismic waves with progressively increasing peak ground acceleration;

[0083] Seismic wave parameters: Peak ground acceleration (PGA) ranges from 0.1g to 1.0g, and waveforms include seismic waves with different spectral characteristics, such as El-Centro, Kobe, and Chi-Chi (CC) waves, to simulate earthquake triggering environments of different intensities;

[0084] (3) Multi-parameter response analysis: During the entire loading process, the acceleration response, inter-layer displacement angle, earth pressure distribution, anchor cable axial force change and anchorage strain data of the model are collected synchronously. By comparing and analyzing the differences in dynamic response under the historical paths of "no deterioration" and "different degrees of deterioration", the coupling superposition mechanism of initial stress redistribution caused by time-varying bearing capacity decay and sudden earthquake load on slope damage is quantitatively evaluated.

[0085] Compared with the prior art, the present invention has the following beneficial effects:

[0086] 1. This method breaks through the limitation of traditional tests that only focus on the static constant bearing capacity of the anchoring system, and can reproduce the real evolution path of "first the bearing capacity of the anchoring system decreases, leading to stress redistribution in the slope, and then being subjected to sudden seismic load".

[0087] 2. This method, through the combination of an adjustable anchoring loading system and multi-level strength rock mass similar materials, can flexibly adjust the anchor cable bearing capacity level and rock mass mechanical parameters according to different test conditions, so as to achieve accurate simulation of slope dynamic response under different service ages and different seismic input conditions. The test is highly controllable and efficient.

[0088] 3. The experimental system of this method has a clear structure and is easy to operate. Each component can be reused, which can effectively reduce the cost of model making and experimental implementation while ensuring experimental accuracy. It has good engineering applicability and promotion value. Attached Figure Description

[0089] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative examples and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application.

[0090] Figure 1 This is a schematic diagram of the overall process of "a shaking table test method that takes into account the time-varying deterioration of the seismic performance of anchored rock slopes".

[0091] Figure 2 A frontal view of the rigid model box used in the experiment.

[0092] Figure 3 A side view of the rigid model box used in the experiment.

[0093] Figure 4 This is a schematic diagram of the arrangement of sensors and monitoring points in the slope model.

[0094] Figure 5 This is a schematic diagram of the prefabricated frame beam structure for a slope model.

[0095] Figure 6 A schematic diagram for creating a prestressed anchor cable model. Detailed Implementation

[0096] The present invention will be further described below with reference to the accompanying drawings and embodiments, so as to make the technical solution and advantages of the present invention clearer. This part will describe in detail the construction of the experimental system, the production of the model, the implementation of degradation simulation, and the specific operation process of the experiment.

[0097] 1. Experimental system setup and sensor arrangement:

[0098] (1) Fixing the vibration table to the model box: Use a lifting device to pass through the model box (e.g., Figure 2 , Figure 3 The lifting rings (as shown) are used to suspend the model box onto the EA-200 vibration table platform; this experiment uses a self-made rigid model box, such as... Figure 2 , Figure 3 As shown, its length, width, and height are 1200mm, 650mm, and 1100mm respectively. The frame of the box is welded from square steel, channel steel, and angle steel. A 12mm thick tempered glass is fixed along the left side of the long side of the model box. A 2mm thick steel plate is welded to the left side of the long side and the front and rear short sides of the model box. The front steel plate is 450mm high, and the left side of the long side and the rear steel plate are 1100mm high. The bottom plate of the model box is a 10mm thick steel plate with dimensions of 2300×1500mm. Holes are punched around the bottom plate, and the hole positions correspond to the hole positions of the vibration table. High-strength bolts are used to firmly fix the model box to the table through the holes around the bottom plate.

[0099] (2) Boundary condition treatment: Flexible boundary: A layer of polyethylene plastic is placed between the model box and the slope model, and a 4-5cm thick polystyrene foam pad is laid on the vibration boundary to simulate the elastic support of the soil in the infinite domain and reduce the reflection of seismic waves.

[0100] (3) Smooth boundary: Apply Vaseline evenly to the inner side of the steel plate on the left side of the model box and lay a plastic film to form a sliding boundary and reduce the friction constraint of the side wall;

[0101] (4) Rough boundary: The bottom steel plate of the model box is roughened to prevent the bottom of the model from sliding relative to the box.

[0102] 2. Monitoring system installation and commissioning: According to... Figure 4 The scheme shown involves deploying sensors inside and on the surface of the slope model;

[0103] Accelerometers: Distributed across five different elevations from the bottom to the top of the slope, these sensors are used to monitor the dynamic amplification effect of the slope.

[0104] Displacement sensors: 2 sets of laser displacement sensors monitor the displacement at the bottom and top of the slope; 2 sets of wire-type displacement sensors monitor the displacement of the upper and lower frame beams;

[0105] Anchor cable axial force sensor: installed between the anchor and the pad to monitor the dynamic axial force of the anchor cable;

[0106] Strain gauges: Installed at key locations in the anchorage section of the anchor cable and the frame beam to monitor local strain;

[0107] Number all sensor data cables and connect them to the dynamic signal acquisition instrument. Perform system debugging to ensure smooth signal transmission.

[0108] 3. Preparation of similar materials for rock mass and fabrication of anchor cable system:

[0109] (1) Preparation of similar materials:

[0110] Based on the multiple linear regression equation, the iron powder content + barite content is adjusted and denoted as... %, the mass percentage of iron powder in the weighting agent %, gypsum content % and glycerin content Precise control of material density, cohesion, internal friction angle, and elastic modulus is achieved using percentages.

[0111] To simulate different service lifespans, three sets of materials with different strengths were prepared:

[0112] High-strength type (newly built): Standard proportions calculated based on prototype parameters;

[0113] Medium-strength type (service life of about 50 years): The new ratio is calculated by back-calculating the regression equation after reducing the target mechanical parameters according to the formula;

[0114] Low-strength type (service life of about 100 years): A new formula obtained by further reducing the target mechanical parameters.

[0115] (2) Fabrication of prestressed anchor cables and frame beams:

[0116] Anchor cable fabrication: such as Figure 5 As shown, 6mm diameter plastic-coated steel strands are used as the free section reinforcement, and 15mm×1mm Q235 stainless steel flat strips are used as the anchoring section reinforcement. The two are connected by an adjustable control device, and the yield axial force and yield length of the anchor cable are set by adjusting the tightness of the device.

[0117] Frame beam fabrication: such as Figure 6 As shown, a prefabricated frame beam model using polymethyl methacrylate (PMMA) is employed.

[0118] Tensioning and Locking: The free end of the model anchor cable is passed sequentially through the slope frame beam, bearing pad, anchoring end clamp, hollow pressure sensor, and hollow bolt assembly; the anchor cable is tensioned by rotating the adjusting nut with a torque wrench or special tool, and the reading of the hollow pressure sensor is monitored in real time during the process; when the reading reaches the set initial target prestress value, the anchoring end clamp or locking nut is tightened immediately to lock the system, thus completing the application and maintenance of the initial prestress.

[0119] 4. Slope model fabrication and equivalent simulation of service life:

[0120] (1) Layered filling of slope model:

[0121] A cellophane sheet printed with the slope outline and sensor positions was fixed on the outside of the model box glass as a reference. The layered compaction method was used to fill and compact the material from bottom to top. During the filling process, acceleration sensors and prefabricated anchor cable models were buried at the designed positions. The potential sliding surface was simulated by a mixture of fine sand, butter and hard plastic film, and its shear strength was controlled by the proportion.

[0122] (2) Service life effect simulation: This experiment simulates different service stages by controlling variables:

[0123] Control group (newly built): Rock mechanical properties: High-strength similar materials were used;

[0124] Anchor cable prestress: Apply 100% of the design prestress (i.e., "0 years" service life);

[0125] Experimental group (different service ages): Anchor cable prestress relaxation simulation: By replacing Q235 steel sheets of different thicknesses and combining with rotating tension nuts, the initial prestress of the anchor cable is actively set to the time-varying bearing capacity value calculated by the formula, so as to equivalently simulate the relaxation of prestress over time.

[0126] (3) Simulation of rock mass and interface performance degradation:

[0127] By using medium-strength and low-strength similar materials to create the entire slope model, the overall mechanical properties of the rock mass itself and its interface with the anchor body are simulated to decrease after approximately 50 and 100 years of service.

[0128] 5. Seismic loading test and data analysis:

[0129] (1) Seismic wave loading: According to similarity theory, if the geometric similarity ratio C_L=50, then the time similarity constant C_t=7.07, and the original seismic wave is scaled down; the seismic wave loading direction is horizontal and unidirectional. The loading scheme shown in Table 1 is adopted, and white noise (0.05g) and El-Centro wave, Kobe wave and Chi-Chi wave are input in sequence, and the ground motion intensity is gradually increased, such as from 0.1g to 1g. White noise is input before and after each set of working conditions to test the change of the model dynamic characteristics.

[0130]

[0131] (2) Test execution and data acquisition: According to the combination described above, the models with different rock mechanical properties and different anchor cable prestress levels were subjected to systematic seismic loading; the multi-parameter synchronous monitoring system was started to collect acceleration, displacement, earth pressure, anchor cable axial force and strain data in real time throughout the process.

[0132] (3) Data analysis: Compare and analyze the dynamic response of models with different "service life" under the same seismic action, such as acceleration amplification factor, displacement accumulation, dynamic increment of anchor cable axial force, etc. Study the influence of time-varying bearing capacity degradation and seismic action superposition on slope dynamic stability, and reveal the evolution mechanism of its failure mode and critical threshold.

[0133] The embodiments described above are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. For those skilled in the art, various equivalent substitutions or improvements can be made to the parameter settings and calculation methods of the above solutions without departing from the principles and essence of the present invention. All such equivalent transformations or improvements should be considered to fall within the scope of protection of the present invention.

Claims

1. A shaking table test method considering time-dependent deterioration of seismic performance of anchored rock slope, comprising the following steps: S1, constructing a comprehensive test system and preparing a physical model: building a test platform composed of a shaking table host, a model box, an adjustable anchoring loading system and a multi-parameter synchronous monitoring system, constructing a scaled rock slope in the model box and laying an anchoring system to form a test slope model; S2, constructing a time-dependent deterioration model of dynamic performance of the anchoring system: based on the failure mechanism of the anchoring system, determining the time-dependent expression form of the mortar-rock interface bond strength, the anchor rod-mortar interface bond strength and the yield resistance of the free section of the anchor cable, and taking the minimum value of the three as the time-dependent bearing capacity of the anchoring system; S3, implementing physical equivalent simulation of interface and component degradation: through the combination of interface degradation simulation and component degradation simulation, the process of time-dependent attenuation of dynamic performance of the anchoring system is equivalently reproduced in the test slope model; S4, performing a "stress redistribution-seismic coupling" loading test: after the bearing capacity of the anchoring system is degraded and the internal stress of the slope is redistributed, the test slope model is subjected to seismic input, and the dynamic response data of the model are collected for analyzing the dynamic response characteristics of the slope under the coupling action of time-dependent deterioration of the anchoring system and seismic action. 2.The shaking table test method for considering time-dependent deterioration of seismic performance of an anchored rock slope according to claim 1, wherein, The comprehensive test system in step S1 is composed of a shaking table host, a model box, an adjustable anchoring loading system, rock similar materials and a multi-parameter synchronous monitoring system; wherein the shaking table host is used to apply seismic input to the model, the model box is installed on the shaking table host for fixing and restraining the slope model, the adjustable anchoring loading system is used to apply and adjust the initial prestress of each anchor cable, the rock similar materials are used to simulate the mechanical properties of the slope rock mass at different service ages, and the multi-parameter synchronous monitoring system includes acceleration sensors, anchor cable axial force sensors, displacement sensors, soil pressure sensors and anchoring segment strain gauges for real-time collection of dynamic response data of the model during the loading process.

3. The shaking table test method for considering time-dependent deterioration of seismic performance of an anchored rock slope according to claim 1, wherein The time-varying bearing capacity is determined according to the principle of "short board effect", that is, the time-varying bearing capacity of the anchoring system at any time The time-varying bearing capacity of the anchoring system at any time is determined according to the principle of "short board effect", that is, the time-varying bearing capacity of the anchoring system at any time The time-varying bearing capacity of the anchoring system at any time is determined according to the principle of "short board effect", that is, the time-varying bearing capacity of the anchoring system at any time The time-varying bearing capacity of the anchoring system at any time is determined according to the principle of "short board effect", that is, the time-varying bearing capacity of the anchoring system at any time The minimum value of the three is determined, and its expression is: The minimum value of the three is determined, and its expression is: The minimum value of the three is determined, and its expression is: The minimum value of the three is determined, and its expression is:

4. The shaking table test method for considering time-dependent deterioration of seismic performance of an anchored rock slope according to claim 1, characterized in that, To realize the physical implementation of the time-dependent deterioration model of dynamic performance of the anchoring system in the shaking table test of step S2, a double-channel implementation method combining interface degradation simulation and component degradation simulation is adopted, including: (1) Interface degradation simulation: by adjusting the mechanical parameters of the rock similar materials, the constraint ability of the rock mass medium to the anchoring system in the model changes with the service time, thereby equivalently simulating the time-dependent attenuation process of the mortar-rock interface bond strength and the anchor rod-mortar interface bond strength; (2) Component degradation simulation: through the adjustable anchoring loading system, different levels of initial prestress or bearing capacity levels are applied to the anchor cable to equivalently simulate the stage-wise attenuation of the bearing capacity of the free section of the anchor cable with the service time caused by factors such as prestress relaxation and component corrosion.

5. The shaking table test method for considering time-dependent deterioration of seismic performance of an anchored rock slope according to claim 1, wherein In the dynamic seismic coupling loading of step S4, after the completion of each level static deterioration simulation, different waveforms of seismic waves or seismic waves with gradually increased peak acceleration are input to the model respectively, and the multi-parameter synchronous response data such as acceleration, displacement, soil pressure, anchor cable axial force and strain are obtained, and the coupling superposition effect of the dynamic performance deterioration of the anchoring system and the slope damage caused by the sudden seismic load is analyzed.

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