Triaxial Creep Tests Research Articles

Microscopic simulation on triaxial compression creep of rockfill based on subcritical crack propagation theory

Over time, natural cracks within particles propagate under tensile stress, leading to the delayed breakage of these particles, which significantly contributes to the time-dependent deformation of rockfill materials. In this study, a delayed strength model for spherical particles with virtual cracks is proposed using subcritical crack propagation theory and validated through indoor single-particle creep tests. Based on the model, particles are represented as ideal spheres in the context of triaxial compression creep simulations for rockfill, with special attention to particle size effects, discreteness, and temporal factors. The combined influence of long-term strength and maximum contact force is crucial in determining the delayed particle breakage. Comparative analysis with indoor triaxial creep tests demonstrates that the Discrete Element Method (DEM) simulations accurately model the creep deformation phenomena related to delayed particle breakage in rockfill. Furthermore, statistical analysis indicates that a minor fraction of delayed particle breakage has a negligible impact on the temporal distribution of the Normalized Maximum Contact Force (NMCF).

Triaxial creep test and damage model study of layered red sandstone under freeze-thaw cycles

To examine the creep behavior and degradation of stratified rock in cold areas, triaxial creep experiments and microscopic analyses were performed on layered red sandstone specimens under freeze-thaw (F-T) cycles. This study revealed the deterioration characteristics and damage mechanisms of red sandstone's creep behavior under the influence of F-T cycles and bedding inclination. The test results showed that: (1) The steady-state creep rates with bedding angles β=30°after 0, 40, 80, and 120F-T cycles were 0.0168 × 10−2·h−1, 0.0224 × 10−2·h−1, 0.0289 × 10−2·h−1, and 0.0368 × 10−2·h−1 respectively. The instantaneous deformation, creep deformation, and steady-state creep rates increased gradually with the increase of F-T cycles, while the long-term strength exhibited a decreasing trend. (2) After 40F-T cycles, the long-term strengths with bedding angles of 0°, 30°, 45°, 60° and 90° were 121.17 MPa, 65.47 MPa, 46.28 MPa, 77.64 MPa and 124.78 MPa, respectively. The bedding angle of 45° has the greatest influence on the triaxial creep properties of red sandstone, followed by the bedding angles of 30° and 60°, and the bedding angles of 0° and 90° have the least influence. (3) As the F-T cycles increases, the longitudinal wave velocity gradually decreases, and the pores and cracks on the sample surface continue to expand, leading to increased damage. The failure mode evolves from a single oblique shear plane to an “X”-shaped tensile splitting. Additionally, the bedding angle has a significant effect on the longitudinal wave velocity. As the bedding angle increases, the longitudinal wave velocity exhibits a “V”-shaped distribution, initially decreasing and then increasing. Based on the test results, a creep damage model of layered rock considering the influence of F-T cycles was established, and the rationality of the model was verified by test data. The research results can provide a scientific basis and technical reference for the long-term stability of layered rock engineering in cold regions.

Insights into the shallow landslide mechanism of expansive soil slope induced by freeze-thaw cycles and snowmelt infiltration

For rigorous understanding the shallow landslide mechanisms and deformation characteristics of expansive soil slopes, a comprehensive in-situ monitoring platform is established. Triaxial creep tests and microstructure analysis with scanning electron microscopy (SEM) are also conducted on expansive soil samples obtained from Binxi station. Field monitoring data indicates that freeze-thaw (F-T) cycle and snowmelt infiltration significantly increase the creep deformation of expansive soil slope during spring melting period. Due to the influence of F-T cycle and snowmelt infiltration, more soil grains are involved in the shear deformation contributing to a large, localized shearing. Additionally, the microstructural analysis shows that F-T cycle influence the relationship between expansive soil grains that gradually change from face-face contact to point-face contact or edge-edge contact form. The shallow landslide mechanisms of expansive soil slope are revealed from creep deformation and microstructure characteristics of soils after the F-T cycle and snowmelt infiltration, which can be summarized into two stages, namely, the snowfall accumulation state and snow melt-shallow infiltration stage. These results can serve as a good reference for the prevention of expansive soil slopes in seasonally frozen regions.

An experimental and theoretical study on the creep behavior of silt soil in the Yellow River flood area of Zhengzhou City

We took the silt soil in the Yellow River flood area of Zhengzhou City as the research object and carried out triaxial shear and triaxial creep tests on silt soil with different moisture contents (8%, 10%, 12%, 14%) to analyze the effect of moisture content on silt soil. In addition, the influence of moisture contents on soil creep characteristics and long-term strength was analyzed. Based on the fractional derivative theory, we established a fractional derivative model that can effectively describe the creep characteristics of silt soil in all stages, and used the Levenberg–Marquardt algorithm to inversely identify the relevant parameters of the fractional derivative creep model. The results show that the shear strengths of silt soil samples with moisture contents of 8%, 10%, 12% and 14% are 294 kPa, 236 kPa, 179 kPa and 161 kPa, respectively. The shear strength of silt soil decreases with increasing moisture content. When the moisture content increases, the cohesion of the silt soil decreases. Under the same deviatoric stress, the higher the moisture content of the silt soil, the greater the deformation will be. The long-term strength of silt soil decreases exponentially with the increase of moisture content. If the moisture content is 12%, the long-term strength loss rate of silt soil is the smallest, with a value of 32.96%. The calculated values of our creep model based on fractional derivatives have a high goodness of fit with the experimental results. This indicates that our model can better simulate the creep characteristics of silt soil. This study can provide a theoretical basis for engineering construction and geological disaster prevention in silt soil areas in the Yellow River flood area.

Creep deformation characteristics and control technology in deep mine soft rock roadway

In order to control the strong ageing creep and large deformation of deep soft rock roadway effectively, with the 61–71 track on the uphill of the mining area in Suzhou, Anhui as the research background, the triaxial creep test of mudstone was conducted using the TYJ-1500 M rock mechanics testing system. The creep deformation and failure characteristics of mudstone were analyzed. Additionally, the creep deformation characteristics of deep soft rock roadways were obtained through FLAC3D numerical simulation experiment, and the control techniques for deep soft rock roadway was proposed. The results showed that the axial strain and lateral strain of the specimen were mainly instantaneous strain and creep strain under triaxial stress conditions, and the both confining pressure and the axial pressure have a significant impact on the deformation and creep failure strength of the specimen. Under the condition of high ground stress and complex geological structure, the high stress concentration of roadway roof and floor and two bottom angles is the main cause of creep failure of soft rock roadway, and the large degree of surrounding rock fragmentation and unreasonable support mode reduce the bearing capacity of surrounding rock and aggravate the creep failure of roadway. The 'anchor net cable shotcrete + floor and two corners in floor bolt-grouting + deep and shallow hole grouting + secondary reinforcement support' combined support method was proposed and industrially tested, with average deformation of the roof, floor, and two sidewalls being 111.9 and 62.5 mm, respectively, representing 13.2 and 10.3% of the deformation under the original support scheme.

Microscopic deformation mechanism and characteristics of carbonaceous slate during the creep process

Carbonaceous slate exhibits a significant creep deformation that seriously affects the construction and operation of underground projects. To investigate the microstructural changes characteristics and reveal the microscopic deformation mechanism of the carbonaceous slate during the creep process, multiple methods were performed, including the triaxial creep test, SEM and MIP. The following conclusions were drawn: The rock samples underwent three stages during the creep test: microporosity closure at a low-stress level, material densification at an intermediate stress level, and microcracks emerging and expanding to failure at the high stress. The creep deformation was particularly significant in the first and third processes. The lamellar particles are compressed or bent under stress in parallel and vertical directions, showing the anisotropic properties of deformation. The deformation of the rock sample is related to the angle between the bedding and the orientation of major principal stress, and the effect of the anisotropy decreases with the increased stress level. The sprouting and expansion of microfractures occur at high-stress levels, showing pressure dissolution of mineral particles, migration of very fine particles, and cement damage between lamellar particles. Finally, the horizontal samples formed a combined rupture surface composed of the laminar surface and the fracture surface intersecting it, showing brittle damage, while the vertical samples formed a fracture surface parallel to the laminar surface, showing a ductile damage pattern. Those results could provide the basis for a further understanding of the mechanical properties of carbonaceous slate and the improvement of its creep model and parameters. It was significant for the stability analysis and deformation prediction of engineering structures using numerical simulation.

Formation mechanism of loess-mudstone landslides in the Weibei Tableland Fault Active Zone of Baoji, China - Taking Wolongsi landslide as an example

The geomorphologic and environmental evolution of the Loess Plateau is greatly affected by the strong fault activity, leading to the frequent occurrence of geological hazards, particularly the loess-mudstone landslide (LML). Thus, it is crucial to investigate the formation mechanism of such landslides in active fault zones. In this study, a field survey was conducted in the Weibei tableland of Baoji where the active fault zone is developed. To study the creep behavior of LML sliding zone soil, the triaxial creep tests of multi-stage loading under different water content, confining pressure, dry density, loess-mudstone binary structure (LMBS) contact surface angle, and thickness were carried out using the sliding zone soil samples (loess, mudstone, and LMBS samples) obtained from Wolongsi landslide in the study area as an example. Experimental results revealed that: (1) Water content has a significant weakening effect on the strength of LML sliding zone soil. The strength of the LMBS sample is extremely water-sensitive. The weakening effect of water on the long-term strength of LML sliding zone soil mainly manifested in promoting the elastoplastic deformation of loess and the viscoplastic deformation of mudstone. (2) The long-term strength of the LML slip zone soil increases linearly with the increase in confining pressure and increases exponentially with the dry density. (3) The degrading effect of the stratigraphic interface dip angle on the long-term slope strength is mainly reflected in the change in the weakening degree of water on the strength of the LML sliding zone. In addition, according to the test results, the traditional Nishihara model is improved by introducing nonlinear parameters, and a new constitutive equation describing LML sliding zone soil is established. The new constitutive model can accurately describe the creep curve's whole process especially sensitively identifying the accelerated creep stage. Finally, after conducting a field investigation and laboratory tests, the main hazard factors affecting the occurrence of the LML were analyzed in the presence of fault activity on the Weibei Plateau of Baoji, China, and its formation mechanism was revealed as well.

Damage evolution of tunnel lining under creep action considering interlayer effect in gently inclined layered surrounding rock

The anisotropy and creep characteristics of layered sandstone mudstone with different structural inclinations have a significant impact on the safety of tunnel construction and operation. we conducted research of the layered sand-mudstone of the Yunding Tunnel on the Dazhou-Chengdu line, based on the mechanical response mechanism of layered surrounding rock and employing a numerical coupling analysis method, established a creep damage mechanical model of layered rock to study the progressive failure characteristics of layered rock and the failure mechanism of tunnel lining. The results indicate that:(1) The response mechanism of layered rock mechanics based on the delamination effect can well reflect the progressive fracture of the layered rock and distinguish the failure mode of layered rock; (2) The established layered rock mechanics contact model can effectively characterize the anisotropic macroscopic mechanical properties of layered sand-mudstone in biaxial test and triaxial creep test; (3) The fracture characteristics of the layered surrounding rock matrix change significantly with the change of the dip angle of the structural plane, the cracks mainly appear in the direction perpendicular to the structural plane. And it can be determined that the critical angle of sliding failure of layered sand mudstone is α1 = 28.77°, α2 = 65.47° (4) The damage evolution of lining can be divided into four states: 1. elastic state 2. injury working state 3. ultimate bearing state 4. damage state. With the increase of the dip angle of the structural plane, the time for the lining to enter the ultimate bearing state is gradually delayed, and the delayed rate shows the characteristics of ’slower-faster-slower’. This research achievement can provide a certain foundation for the analysis of the failure mode and the failure mechanism of tunnel lining.

Investigation of creep characteristics and microscopic mechanism of cemented-soil subjected to freeze-thaw

With the development of underground construction, higher safety demands have been placed on construction methods. The improved freezing method, which combines artificial ground freezing and cemented soil stabilization techniques, is more suitable for studying the typical creep characteristics of muddy clay in Shanghai. However, research on the creep behavior of freeze-thaw cemented-soil is limited. In this study, the creep characteristics of freeze-thawed cemented soil were investigated through triaxial creep tests, and the micromechanism was explored using scanning electron microscopy (SEM). The results indicate that the creep deformation of freeze-thawed cemented soil is higher than that of non-freeze-thawed cemented soil. The freezing temperature decreased with an increase in deformation. By analyzing SEM images, the porosities of non-freeze-thawed cemented-soil and soil freeze-thawed at -5°C, -15°C, and -25°C, were extracted, which were 28.5%, 28.7%, 30.1%, and 39.1% respectively. During the freeze-thaw cycle, both the soil and cemented soil particles undergo movement and reordering. Freeze-thaw exacerbates creep degradation because frost heave weakens particle adhesion and affects structural stability. These results provide a scientific reference for the development of underground spaces in soft areas.

Damage creep model of viscoelastic rock based on fractional derivative and experimental verification

Exploring the creep law of sandstone provides a theoretical basis for evaluating the long-term stability of geotechnical engineering projects in red beds. Based on a conventional triaxial test of sandstone, a progressive loading triaxial creep test is conducted. The deformation characteristics and laws of each sample in different deformation stages are summarized, and the laws relating steady creep rate, stress and time are analyzed. On this basis, a nonlinear viscoelastic‒plastic creep model based on fractional derivative theory and damage theory is established. According to the nonlinear fitting results, the parameter sensitivities are analyzed. The results verify the rationality of the model; this model has a good fitting effect for each creep deformation stage, especially for the accelerated creep stage. The constitutive relationship of the model is simple, clear and easily applicable. The research results provide a reference for studying the long-term stability of geotechnical engineering projects.

Particle gradation effects on creep characteristics and the underlying mechanism in calcareous sand

Calcareous sand, a foundation material of marine origin, is an indispensable component in marine construction and has found extensive applications in building foundations and airport runways. The complex nature of the marine environment and the unique characteristics of calcareous sand present significant challenges for ensuring the stability and durability of engineering structures. To address these challenges, multistage loading triaxial creep tests were conducted on calcareous sands with different particle gradations to analyze their creep characteristics and underlying mechanisms. The result shows that the amount of ultimate axial creep strain is positively correlated with deviatoric stress but negatively correlated with the coefficient of uniformity (Cu). The creep process demonstrates a significant creep structure effect, characterized by creep rate lag and creep failure lag. The volumetric creep strain-time relationship at different creep stress ratios can be classified into three types. When the creep stress ratio is less than the stress ratio at the dilative point, the sample is first compacted followed by dilatancy; when the creep stress ratio is equal to the stress ratio at the dilative point, only compaction is obtained; as the creep stress ratio becomes larger than the stress ratio at the dilative point, pure dilatancy is found. The particle crushing modes and creep mechanisms of calcareous sand are also examined through meso-observations. It is found that the particle crushing modes can be categorized into three distinct types: grinding, angular breakage, and whole particle breakage. The particle gradation not only impacts the primary particle crushing mode but also governs the movement of particles and fragments, thereby influencing the occurrence of creep deformation. Specifically, a smaller Cu value corresponds to a higher fragmentation rate of the specimen, an increased number of overall crushing and angular fractures, a larger space for fragment migration after crushing, and eventually a greater creep deformation. Finally, a modified Burgers model is proposed based on the test results, which can effectively capture the creep deformation in the presence of creep structure effects and creep failure stages.

Study on creep characteristics of granite of deep tunnel affected by joint orientation

Joints are an important part of rock masses and the spatial relationship between joint orientation and in situ stress (or tunnel axis) has a significant impact on the deformation, strength, and failure behavior of the surrounding rock. To study the influence of joint orientation on creep characteristics of deep hard rock, the true triaxial creep tests were performed in the laboratory on natural jointed granite under different loading angles ω (defined as the angle between the strike of the joint plane and σ2-direction) conditions. The test results show that ω has a significant effect on the time-dependent deformation and failure characteristics of the jointed rock. As ω increases, there is a decrease in creep deformation, steady creep rate in the σ3-direction, and value of the DI index (used to evaluate the difference in the time-dependent deformation in the σ2- and σ3-directions). Stress-structure-controlled failure (sliding along the joint plane) occurs when ω ≤ 30°. However, when ω > 30°, the failure of the jointed granite is not affected by joint and stress-controlled failure occurs. The stress-structure-controlled time-dependent failure evolution enters a stage that is dominated by shear cracks earlier than stress-controlled failure according to AE results. In addition, the time-dependent failure went through stages of microcracks initiation and interaction, stable crack growth and unstable crack propagation. And when the time-dependent failure evolution enters the unstable crack propagation stage, the nature of the cracks changed from tensile-dominated to shear-dominated.

Experimental Study on Creep Characteristics of Loess with Different Compactness

Creep deformation control is the key point and difficulty in the construction of loess high fill, the creep characteristics of loess with different compactness and confining pressure conditions has been studied. To achieve the objective, the influence of different conditions on the creep deformation characteristics of loess were analyzed by the triaxial creep tests of loess under different compaction and confining pressures. The results show that the instantaneous deformation of the soil samples gradually decrease with increasing compactness, and the total creep deformation also decreases. With the increase of confining pressure, the deformation increase gradually with the compactness decreased. Finally, in order to describe the creep process of loess, the creep model suitable for different compactness is proposed, which is based on fractional calculus and the continuous damage theory. Through fitting verification, the applicability of the theoretical model to the description of loess creep characteristics is proved, and then the whole stages of loess creep can be better described.

Pore-pressure and stress-coupled creep behavior in deep coal: Insights from real-time NMR analysis

Understanding the variations in microscopic pore-fracture structures (MPFS) during coal creep under pore pressure and stress coupling is crucial for coal mining and effective gas treatment. In this manuscript, a triaxial creep test on deep coal at various pore pressures using a test system that combines in-situ mechanical loading with real-time nuclear magnetic resonance (NMR) detection was conducted. Full-scale quantitative characterization, online real-time detection, and visualization of MPFS during coal creep influenced by pore pressure and stress coupling were performed using NMR and NMR imaging (NMRI) techniques. The results revealed that seepage pores and microfractures (SPM) undergo the most significant changes during coal creep, with creep failure gradually expanding from dense primary pore fractures. Pore pressure presence promotes MPFS development primarily by inhibiting SPM compression and encouraging adsorption pores (AP) to evolve into SPM. Coal enters the accelerated creep stage earlier at lower stress levels, resulting in more pronounced creep deformation. The connection between the micro and macro values was established, demonstrating that increased porosity at different pore pressures leads to a negative exponential decay of the viscosity coefficient. The Newton dashpot in the ideal viscoplastic body and the Burgers model was improved using NMR experimental results, and a creep model that considers pore pressure and stress coupling using variable-order fractional operators was developed. The model’s reasonableness was confirmed using creep experimental data. The damage-state adjustment factors ω and β were identified through a parameter sensitivity analysis to characterize the effect of pore pressure and stress coupling on the creep damage characteristics (size and degree of difficulty) of coal.

A viscoplastic constitutive model for unsaturated soils based on nonstationary flow surface theory

AbstractA viscoplastic constitutive model is developed to describe the viscoplastic behavior of unsaturated soils. The proposed model accounts for the stain‐rate and suction effects on yield by adopting an unsaturated isotach concept. The nonstationary flow surface theory (NSFS) is applied for modeling the viscoplastic behavior, with the yield surface which can evolve with the viscoplastic strain, viscoplastic strain rate and suction. Meanwhile, the progressively hardening concept is adopted for reproducing the viscoplastic behavior of soil at an over‐consolidated state. For the validation, a series of loading conditions are considered based on the data from the literature. Results show that the proposed model is able to reproduce the main viscoplastic behaviors of unsaturated highly compacted Gaomiaozi (GMZ) bentonite, Glenroy silt and Qianjiangping landslide (QL) soil, including CRS compression tests, rate‐dependent triaxial shear tests, and triaxial creep tests.

The creep characteristics and related evolution of particle morphology for calcareous sand

In the study, the creep characteristics and meso-mechanism of calcareous sand under different stresses are explored through triaxial creep tests. The influence of particle size on calcareous sand creep is also considered. Furthermore, the particularity of calcareous sand creep is revealed by comparing with the creep behavior of silica sand. The results show that during creep, the calcareous sand is more stable than silica sand due to the interlocking of irregular particles. When creep deviatoric stress is small, the creep of calcareous sand is manifested as nonlinear attenuation creep (primary creep), and the creep deformation is smooth without creep failure. With the increase of creep deviatoric stress, the creep deformation is concentrated, resulting in a strain concentration zone similar to the shear band, and the associated creep rate first decreases and then suddenly increases, finally, creep failure occurs. With increasing particle size of calcareous sand, the particle crushing increases, which induces a higher creep deformation, however, the overall creep failure is not generated. During the graded creep of calcareous sand, an obvious creep structural effect is observed, which is temporary and results in a significantly reduction of creep rate. Only after the previous creep structure effect is destroyed by the continuously creep process, the creep response can restore to its original behavior. The meso-behavior is represented by particle morphology, i.e., the fractal dimension and aspect ratio. It is found that both confining pressure and particle size can influence the evolution of particle morphology during creep. With the increase of confining pressure, the fractal dimension of calcareous sand decreases which means that particle grinding is always existent, while the aspect ratio of small-sized calcareous sand after creep decreases first and then stabilizes (slightly increases), suggesting that the overall particle breakage is the main cause of deformation. However, the aspect ratio of large-sized calcareous sand continually decreases, indicating that the main contribution for its deformation is angular cracking. The mesoscopic behavior of silica sand is basically unaffected by creep, and its creep deformation is mainly caused by particle rearrangement.

Triaxial creep test and PFC numerical simulation of rock-like materials with cracks

Triaxial creep test and PFC numerical simulation of rock-like materials with cracks

Investigation on the triaxial creep characteristic of coarse granular materials with different initial void ratios

The creep deformation of coarse granular materials is closely related to the state of creep stress and the degree of compaction. A serious of triaxial creep tests using the single-line method were carried out to investigate the influence of initial void ratio and triaxial stress state on the creep deformation and creep strain direction of coarse granular materials. The test results primarily indicate that the creep strain increases with an increase in initial void ratio under identical stress conditions, and the volumetric creep strain decreases with an increase in stress ratio under high confining pressure conditions. Furthermore, the variation in the initial void ratio has little influence on the direction of creep strain under the same creep stress state. The effect of generalized stress on the final creep strain and creep dilation ratio were further discussed. It was observed that the final deviatoric creep strain exhibits a stronger correlation with the deviatoric stress q compared to the mean normal stress p. Additionally, the creep dilatancy decreases with an increase in stress magnitude under identical stress ratio conditions. Based on the test results, a computation model for the final deviatoric creep strain with the consideration of initial void ratio and creep stress was proposed by modifying a basic power function with deviatoric stress q as the variable. After that, a modified stress-dilatancy equation for coarse granular materials was used to predict the direction of strain during creep process. Finally, the final volumetric creep strain was indirectly calculated by integrated the computation model for the final deviatoric creep strain and the creep stress-dilatancy equation. The reasonable of the proposed model was verified through a comparison of computation results and test results.

Emphasizing the Creep Damage Constitutive Model of Hydro-Mechanical Properties of Rocks: A Case Study of Granite Gneiss

The constitutive model of rock materials can describe the mechanical behavior of rocks in creep tests. Also, it is one of the important means to study the deformation and strength characteristics of rocks in complex stress environments. This paper is based on the analysis of the porosity variation characteristics of the internal structure under the coupling effect of rock hydro-mechanical properties. The concept of the hydro-mechanical properties variable is proposed, and the relationship between the coupling variable, damage and plastic deformation is established. By introducing the coupling variable, instantaneous damage variable and time-dependent damage variable into the yield surface equation, as well as the plastic potential energy equation and the stiffness matrix of the elastic–plastic creep constitutive equation, a hydro-mechanical properties creep damage coupling model was established to simulate the creep mechanical properties of rock under coupling. Based on the triaxial creep test results of granite gneiss, the model parameters are determined. By comparing the test results with numerical results, it was revealed that the model can better describe the creep mechanical properties of rocks under the coupling effect of hydromechanical properties.

The Secondary Development and Application of the Improved Nishihara Creep Model in Soft Rock Tunnels

Given the complexity and diversity of rock formations, existing constitutive models struggle to accurately portray their mechanical properties, leading to substantial discrepancies between numerical simulation outcomes and reality. This inadequacy fails to meet the demands of numerical analysis in practical engineering. This study first analyzes the physical and mechanical properties of thin-layered carbonaceous phyllite. Subsequently, an improved Nishihara rheological constitutive model is established based on these analyses. Utilizing the secondary development function offered by FLAC3D, the proposed model is further developed. The program’s correctness and reliability are confirmed through a numerical simulation using the triaxial creep test from existing research. Finally, the established constitutive model is applied in the numerical simulation of an actual soft rock tunnel engineering, obtaining results compared to real monitoring data. The results demonstrate that the improved Nishihara model is more effective at describing the creep deformation characteristics of soft rock. Moreover, the findings from this study can serve as a theoretical reference for predicting deformation in soft rock tunnel engineering.