Large Deformation Characteristics Research Articles

Simulation of droplet bouncing on flexible substrate in 2D and 3D with WC-TL SPH method

Droplet impacts on super-hydrophobic surfaces play an important role in many fields. Previous studies have focused on rigid substrates and ignored the effect of substrate deformation. Simulating droplet impacts on a flexible substrate is a challenge to numerical methods due to the coupling of free surface, elasticity, large deformation and surface tension. In this study, a fully meshfree model of fluid–solid interaction is developed based on the smoothed particle hydrodynamics (SPH) method. The liquid droplet is modeled by the weakly compressible (WC) SPH method, and the flexible substrate is modeled by the total Lagrangian (TL) SPH method. Liquid surface tension is modeled by the continuum surface force (CSF) method through reconstructing the free surface of the droplet. The surface geometry reconstruction process is given for both 2D and 3D cases, enabling the model to simulate the bouncing of droplets in both 2D and 3D cases. Furthermore, in order to reduce the computational cost of 3D simulation, the TL-SPH model combined with shell theory established the TL-SPH-shell model, thus achieving the simulation of 3D droplet impact on thin plates. For verification and testing, the established WC-TL SPH model is used to simulate the process of droplet impact on various substrates, including fixed-fixed and curved beams, micro-pillar substrates, and cantilever beams. The results show that the spreading, retraction and bouncing processes of the droplets interact with the deformation and recovery of the flexible substrate, accompanied by large deformation and dynamic characteristics, which can be effectively simulated by the model.

Study on Stress Disturbed Mechanism and Supporting Method of Weakly Cemented Roadway near Chambers

After excavation of the weakly cemented roadway adjacent to the chambers, deformation characteristics such as roof subsidence, roadway extrusion, and floor heave appear, showing the characteristics of large deformation of surrounding rock, long deformation duration, and serious damage, which are not conducive to guaranteeing safety mining. Based on the technical means of the rock mechanical property test, mineral composition analysis, in situ stress test, and surrounding rock deformation monitoring of 2# coal roadway in Hongqingliang coal mine, a numerical simulation study on the influence of surrounding rock stress on adjacent chamber groups was carried out. The physical and mechanical properties of the weakly cemented rock were obtained, the stress distribution law of the 2# coal roadway was mastered, the deformation characteristics of the surrounding rock of the weakly cemented roadway were obtained, and the deformation and failure mechanism of the weakly cemented roadway adjacent to the chambers were revealed. The relationship between the regional stress increment of the chambers and the failure range of the surrounding rock of the roadway is revealed, establishing a mechanical model of allowable deformation + stress release + controlled form with U-shaped steel as the main structure. The roadway support countermeasures were given and applied in engineering practice.

Research on the deformation control of surrounding rock about large-section tunnel in strong-medium weathered slate

Affected by dip angle and thickness of strata and the tunneling method, soft rock tunnel has obvious characteristics of large deformation, long deformation time and difficult support. Based on a case study of Gelong the deformation and failure mechanism of surrounding rock, stress characteristics of supporting structural and control method of large section highway tunnel passing through strong-medium weathered carbonaceous slate stratum are studied. This paper proposed construction method based on strengthening the longitudinal stiffness of supporting structure and increasing the integrity of surrounding rock, The results showed that the deformation of surrounding rock and the stress of supporting structure increased rapidly in the early stage of construction. The cumulative deformation of vault settlement and horizontal convergence reached 116.9 mm and 97.9 mm, respectively, accounting for 73.53% and 76.62% of the total deformation. The proportion of surrounding rock pressure shared by the primary support and the secondary lining was about 8.9:1.1. This shows that the initial support after comprehensive reinforcement has a strong supporting capacity, and effectively reduces the secondary lining pressure of the tunnel, which plays a vital role in the long-term service of the secondary lining.

Thermo-mechanical large deformation characteristics of cutout borne multilayered curved structure: Numerical prediction and experimental validation

The numerical modeling of static large-deformation behavior of the multilayered flat/curved panels with cutouts subjected to thermo-mechanical load is presented in this work. The numerical model includes third-order displacement polynomials. The large-deformation characteristic of the multilayered panel is incorporated using two nonlinear strains (Green–Lagrange and von-Karman). The governing equation is formulated using Hamilton’s principle, and approximate numerical solutions are obtained using the selective integration scheme (Gauss-Quadrature) associated with Picard’s direct iterative method. A generic computational algorithm is developed in MATLAB using isoparametric finite element (FE) steps. The solution accuracy is verified with the published results and experimental data by utilizing the available/fabricated lab-scale test rig. The role of cutout parameters, including the various geometrical parameters on the nonlinear structural responses, is studied for a clear insight into the damaged structural modeling using the temperature-dependent elastic properties of the laminate. In addition, the effect of nonlinear strain terms on the final structural responses is presented. Based on the observation, the applicability of the full geometrical (Green–Lagrange) strain–displacement relation is established.

Research on the Dynamic Behaviors in the Sliding Friction of Silicone

With the promotion of soft viscoelastic materials in the field of flexible bionic robots, the behavior of sliding friction between soft viscoelastic materials and rigid materials such as metals has attracted great attention. In this study, the research object was silicone, and a research method combining a dynamic force testing technique and a non-contact optical testing technique for deformation and strain was proposed to study the frictional behavior of silicone and the effect of the tooth structure surface on the sliding friction. We analyzed the temporal changes in the friction force for different loads, the dynamic characteristics of large deformation and micro-strain on the front side (define the contact surface as the bottom surface) of the silicone. The results showed that within a certain range, the sliding friction coefficient of the silicone increased monotonically with increasing load, and there were stick-slip and deformation waves during the relative motion. The larger the load was, the faster the deformation wave propagated, and the tooth structure surface had sliding friction anisotropy.

Residual Strength Estimation Method of Soft Coal Based on Equivalent Residual Strain Ratio

In underground mining engineering, the residual strength of surrounding rock has an important influence on the secondary stress distribution caused by excavation. Generally, the residual strength of coal can be measured by experiments, but for soft coal, due to its large postpeak deformation characteristics and the limitation of strain sensor range, it is difficult to measure residual strength. Therefore, it is of great practical significance to estimate the residual strength of soft coal with incomplete stress-strain curves. In this paper, a method for estimating residual strength of soft coal based on the ratio of equivalent residual strain to peak strain is proposed. Taking advantage of the characteristics that the strain-softening curve of soft coal decreases approximately linearly in the initial stage, keeping the drop modulus unchanged, the endpoint of the extension line can be determined based on the ratio of equivalent residual strain to peak strain, which is estimated residual strength. There are 342 groups of typical complete stress-strain curves analyzed to determine the value range of the ratio of equivalent residual strain to peak strain. It is concluded that for briquette composed of soft coal, the ratio of equivalent residual strain to peak strain is between 1 and 3.35 when the confining pressure is 0-6 MPa, and the maximum probability interval of the ratio value under different confining pressures is further calculated. When the confining pressure is higher than 6 MPa, the briquette composed of soft coal tends to ideal plastic state after peak. The feasibility of the residual strength estimation method is verified by comparing the numerical simulation results of triaxial compression of coal pillars with the experimental results.

Implementation of printability for magneto-active soft materials based on programmed 3D printing technique

Magneto-active soft materials fabricated by new paradigms of 3D printing have received considerable interest for various applications owing to their remarkable complex deformation and extraordinary magneto-mechanical properties. The morphology and magneto-mechanical properties of materials prepared by direct ink writing (DIW) 3D printing, on the other hand, are closely related to process and material parameters that are critical in this printing technique. In this study, the morphology of ink filaments printed under different parameters was investigated through theoretical analysis and experimental tests to achieve the implementation. The results demonstrated that the prepared magnetic inks are suitable for DIW, and the predictions based on a simplified hydrodynamic model are basically consistent with the measured data in the experiments. It also showed that the diameter of the extruded ink filaments increases with increasing extrusion pressure, and decreasing printing speed, layer height, and magnetic particle content. Similarly, the magnetic property varies with the nozzle diameter and material composition variations. Using the obtained optimal parameters, several magneto-active rods and plate-like structures with a specific arrangement of microscopic magnetic domains were successfully fabricated. Their magnetically driven behavior further was investigated experimentally and numerically, which revealed a programmed, non-contact remote control, reversible, and multimodal large deformation characteristics. The findings of this study allow a more in-depth understanding and analysis of processing-structure-property correlations of printed magneto-active soft materials, laying the groundwork for personalized customization and versatile development of magneto-mechanical performance.

Electro-thermally driven biaxial bending artificial muscle based on oriented graphite nanoplate nanocomposite/polyimide complex structure

In recent years, artificial muscle is of great research interest due to its promising application. However, low deformation, complicated fabrication process, and high cost hinder their development. Herein, electro-thermally driven biaxial bending artificial muscle based on oriented graphite nanoplate nanocomposite (GN)/polyimide (PI) complex structure is successfully fabricated by cost-effective process utilizing coefficient of thermal expansion difference between them. GN/PI bi-layer films were further assembled and packaged into multi-unit biaxial bending actuator, which could extend and contract like artificial muscle. The unique characteristics of large deformation, easy control, low cost and simple fabrication process distinguish the GN/PI bi-layer based artificial muscle from others. Driven by the voltage of 10 V, the artificial muscle could reversibly reach a shrinkage rate of 11% and a maximum lifting height of 2.5 cm with the object weight of 5.0 g. Moreover, a walking robot has also been designed to achieve a large displacement.

True 3D geomechanical model test for research on rheological deformation and failure characteristics of deep soft rock roadways

Deep soft rock roadways generally present large deformation characteristics, and a vast number of workers attempt to repair them to no avail. A true 3D model test was performed based on the engineering background of the transportation roadway of the Huafeng coal mine in China. The selected analogous materials have a significant time similarity relationship with the surrounding rock, and a similar bolt-mesh-shotcrete support structure, according to the engineering background, was applied to the roadway. The test results showed that the evolution process of the rheological deformation of the roadway is two sidewalls → floor → vault → full-section convergence of the roadway. The large deformation zones of the surrounding rock are constantly transferred from the surface to the depth, and the bearing capacity of the bolts decreases rapidly after the deformation of the anchorage zones. The mechanical characteristics of the floor determine that the lower surrounding rock always repeats the failure process of the upper rock stratum, and the floor heave does not stop. The test results revealed the full-section convergence rheological deformation laws and migration laws of the internal key deformation locations of the surrounding rock and clarified the reasons for the floor heave. The model test results are verified through field monitoring, and opportunities and suggestions for secondary support are determined. These results could provide a reference for the failure process and control technology of the same type of deep soft rock roadway.

Study on Failure Mechanism and Control Technology of Roadway Surrounding Rock under Complex Occurrence Coal Seam

Aiming at the characteristics of large deformation and long deformation time under the mining influence of the 2254 east floor roadway surrounding rock, which under the condition of complex coal occurrence in Jiahe Mine. Through the actual measurement, it is found that the mineral composition of the roadway surrounding rock is mainly siderite, and it also contains 9.52% of kaolinite minerals, and the surrounding rock is relatively weak. Through drilling and peeping, it is found that the roadway surrounding rock is mainly thin-layered, and a large number of fissures are developed in the surrounding rock near the surface of the roadway. Through the in situ stress test, it is concluded that the in situ stress field of Jiahe Mine is dominated by horizontal stress, the minimum principal stress is vertical principal stress, and the lateral pressure coefficient exceeds 2, causing serious damage to the two sides of the roadway. Using the gas drainage drilling data of the 2254 east floor roadway and using SketchUp and Rhino software, the complex geological occurrence model of the coal seam above the roadway was constructed, and on this basis, the FLAC3D numerical calculation model was constructed. The analysis results show that the plastic zone of the roadway surrounding rock is large, the bolt anchoring section is within the plastic zone, and the control effect on the deformation of the roadway surrounding rock is poor. Therefore, a comprehensive support method of “reserved deformation, anchor rod, metal mesh, shotcrete, grouting anchor cable, and full-section grouting” is proposed. The monitoring results of the surrounding rock deformation of the roadway 12 months after construction show that the support scheme can effectively control the deformation of the roadway surrounding rock. The research results provide a reference for the stability control of similar roadways.

Sealing mechanism of large size and large deformation rubber cylinder for pipeline intelligent plugging robot under multiple factors

Large-volume rubber cylinder is a core component of pipeline intelligent plugging robot (PIPR). It is used for plug pipe section during pipeline rerouting, maintenance, and repair operations to prevent large-area leakage of pipeline oil and gas. This paper studies the sealing mechanism of large size and large deformation rubber cylinder of the PIPR under the influence of different rubber materials, axial length, radial length and inclined angle. Based on large deformation characteristics of rubber material, the theoretical mechanics of rubber cylinder were deduced and analyzed. Constitutive test of rubber material was carried out, and constitutive relationship parameters of rubber material were obtained. The finite element simulation model of rubber cylinder sealing mechanism analysis is established, and the influence of various system parameters and working conditions on the model is considered. In addition, visible indoor tests were established to verify the simulation model. It showed that stress concentrated on the apex and shoulder inside the rubber cylinder directly affected the deformation damage of rubber cylinder. After comparing the analysis result of the sealing effect of rubber cylinder under various parameters, it is concluded that the optimal rubber cylinder structure is 180 mm in axial length, 55 mm in radial thickness, 28° inclination angle, and hardness of rubber material is 85HA. This study provides a reference for the optimization design of rubber cylinder of PIPR. It has important engineering significance for the successful implementation of the plugging operation.

An Optimization Method for Clearance Value of Electric Submersible Screw Pump

Electric submersible screw pump often works at high speed, which has the characteristics of high speed, high temperature and large rubber deformation. In case of sudden shutdown, the rubber will not shrink at high temperature, which may lead to serious accidents such as pump locking and electrode burning. In the initial stage of pump start-up and restart after pump shutdown, due to the above reasons, it is often difficult to start the pump, which makes the pump unable to work normally. Therefore, this paper studies the clearance value of the electric submersible screw pump, calculates and tests the interference amount and initial interference amount, improves and optimizes the clearance value of the electric submersible screw pump, effectively improves the working efficiency and service life of the electric submersible screw pump, achieves the purpose of improving the quality and efficiency of oilfield production, and has a very important practical significance for the development of the rodless pump market.

Comparative Study on the Anchor Performance of Wooden Tension Anchor Bolts and Tension–Compression Composite Anchor Bolts in Earthen Sites

ABSTRACT The full-length bond wood tensile anchor system (WTS) conventionally used in earthen sites is primarily broken by the debonding of the bolt–slurry interface. To solve this limitation, material performance and pull-out tests were performed for a new type of wood tension–compression composite anchor system (WTCS) and WTS, and the strain of the bolt–slurry and the slurry–soil interface were monitored. A comparison of test results indicated the following: The average pull-out force of the WTCS is approximately 23–51% higher than that of the WTS. The WTCS has the strong ductility characteristics of small elastic and large plastic deformation. As the load increases, the strain at the bolt–slurry interface changes from a negative index of low strain to a high-strain “S” curve at the end along the bond length. The peak value of slurry–soil interface strain exhibits a transition from the front part of bond length to the middle and back parts of bond length. The mechanical operating mechanism between bolt and slurry is divided into three simplified progressive structural force models, namely “1,” “T,” and “Y.” Finally, the calculation formulas of the average pull-out force of the WTCS are provided.

Large deformation characteristics and treatment effect for deep bias tunnel in broken phyllite: A case study

The support structure of deep buried tunnel often encountered bias load of during construction in weak layered strata. This paper studied the support structure failure behavior and surrounding rock deformation mechanism with Wuduxi Tunnel as an engineering case. The tunnel presents the damge phenomenons such as primary support cracking, steel arch distortion, secondary lining sidewall extrusion under asymmetrical load and high geostress. Firstly, the laboratory test was producted to research the engineering characteristics of the broken phyllite. The field test results show that the surrounding rock pressure is unevenly distributed around the tunnel, the primary support is all under pressure and the secondary lining is partial in tension. The surrounding rock pressure distribution shows an ellipsoidal distribution consistent with the trend of the rock stratum. The maximum vault settlement and horizontal convergence are 165.58 mm and 282.56 mm, respectively, and the convergence rate is far more than the stable deformation rate in the specification, which proves that the existing specification is not applicable to the large deformation deep buried bias highway tunnel with soft rock. Furthermore, the construction methods of “double primary support-secondary lining” are proposed to control the large deformation of surrounding rock. The field test is carried out to verify the feasibility of the double layer primary support. The field test show that the large deformation can be effectively controlled, and the support structure was stable without crack and damage, which ensured the construction safety of the deep buried bias tunnel in broken phyllite.

Large Deformation Characteristics of Surrounding Rock and Support Technology of Shallow-Buried Soft Rock Roadway: A Case Study

The coal resources in the coal-rich area of western China are mostly located in the late diagenetic Cretaceous and Jurassic strata. In this paper, a study on the support of soft rock roadways was carried out in the background of the soft rock track roadway in the Jiebangou coal mine. The field investigation showed that the surrounding rocks of the roadway were weak, soft, and broken, and the surrounding rocks were cemented, with the roadway local deformation exceeding 1 m. The borehole television results showed that the surrounding rocks were mainly weak sandy mudstone and yellow mudstone. The average uniaxial compressive strength of the surrounding rock was 15.49 MPa. The roadway is a shallow buried soft rock roadway; site investigation revealed that the original U-shaped steel shed had an extremely low resistance to slip, the filling body behind the U-shaped steel shed fell off, the interaction between the U-shaped steel shed and the surrounding rock was poor, the U-shaped steel shed could not provide sufficient timely support resistance, and the bearing capacity of the U-shaped steel shed was far from consideration. The floor was not effectively supported. The floor had different degrees of the bottom drum, and frequent undercover caused new stress disturbances, which loosened the bottom corners of both rock types and made the shed legs move continuously inward, reducing the bearing capacity and actual support resistance of the bracket. Numerical calculations were performed to study the deformation characteristics of the surrounding rock of the tunnel and the yielding damage characteristics of the brace. The results showed that the current U-shack support strength was insufficient, the two sides were deformed by 950 mm, the bottom of the roadway bulged by 540 mm, and the surrounding rock was mainly shear damaged. The fall of the filler behind the shed caused damage to the U-shaped steel shed spire. Through site investigation results and numerical calculations, the deformation and damage characteristics of the soft rock roadway and its damage causes were analyzed, and the support technology system of ‘strengthening support for weak structural parts’ was proposed. This improved the mechanical properties of the weak structural support body, the stress state of the local surrounding rock, and the bearing capacity of the support structure, and effectively controlled the deformation, damage, and instability of the surrounding rock of the roadway, and deformation, damage, and destabilization of the roadway, thereby achieving overall stability for the surrounding rock of the roadway.

Design and Fabrication of Pneumatically Actuated Valveless Pumps.

In this study, a valveless pump was successfully designed and fabricated for the purpose of medium transportation. Different from traditional pumps, the newly designed pump utilizes an actuated or a deflected membrane, and it serves as the function of a check valve at the same time. For achieving the valveless property, an inlet or outlet port positioned in an upper- or lower-layer thin membrane was designed to be connected to an entrance or exit channel. Theoretical analysis and numerical simulation were conducted simultaneously to investigate the large deformation characteristics of the membranes and to determine the proper location of the inlet or outlet port on the proposed pump. Then, the valveless pump was fabricated on the basis of the proposed design. In the experiment, the maximum flow rate of the proposed pump exceeded 12.47 mL/min at a driving frequency of 5.0 Hz and driving pressure of 68.95 kPa.

In Situ Needle Penetration Test and Its Application in a Sericite Schist Railway Tunnel, Southwest of China

AbstractThe sericite schist is a typical metamorphic soft rock. Large deformation of surrounding rock often occurs in the construction of a tunnel in this stratum. Due to the broken rock mass structure and poor mechanical strength in Baishitou tunnel project of Dalin line of Southwest railway, it is impossible to prepare standard samples for a traditional rock mechanical test. Therefore, we chose penetrometer (SH-70) for an in situ test. Firstly, we monitored the deformation of typical sections and analyzed the characteristics of large deformation of soft rock in the tunnel. Secondly, we tested the needle penetration index of fresh excavation face and side wall. Then, we estimated some mechanical parameters of sericite schist by a needle penetrometer and Hoek-brown criterion and discussed the acquisition of mechanical parameters of soft rock. The results show the following: (1) the characteristics of extrusion rock tunnel are summarized as large deformation, fast deformation rate, and obvious construction disturbance. (2) The reference value of penetration index of sericite schist (the vertical joint direction) is 3.90~7.77 N/mm, and the parallel joint direction is 1.27~2.99 N/mm. (3) The uniaxial compressive strength estimated by a penetrometer is 0.78~8.53 MPa, and the strength of the surrounding rock is negatively correlated with the amount of deformation. Therefore, it can be considered that the insufficient strength of surrounding rock is the fundamental reason for large deformation. (4) The reference value of cohesion of sericite schist estimated by a penetrometer is 0.203 MPa, and the reference value of internal friction angle is 18.224°. Compared with the common estimation methods, the penetrometer is more convenient and economical, which can provide a new idea for obtaining the mechanical parameters of sericite schist soft rock tunnel.

Key factors analysis and constitutive equation modification of a macro-NPR bolt for achieving high constant resistance and large deformation characteristics

A macro-NPR (negative Poisson's ratio) bolt, also called a He bolt, is a composite structure that is composed of two types of steel that are adjusted by design. The mechanical characteristics of the macro-NPR bolt are high constant resistance, large deformation, energy absorption, and impact resistance. In this work, the concepts of a “climbing angle” and a stick-slip element were introduced to analyze the mechanical behavior of the macro-NPR bolt. It was observed that certain bottleneck problems in the existing constitutive model of the macro-NPR bolt had not been solved: (1) The calculation equation of stick-slip displacement included some parameters with weak correlation. (2) In calculating a single stick-slip cycle, the displacement was assumed to be instantaneously completed, whereas the cone sliding process was considered. (3) The random stick-slip phenomenon had a great influence on the performance of the macro-NPR bolt. These problems could lead to significant differences between the existing macro-NPR bolt static tension theoretical curve and the experimental curve. To solve these bottleneck problems, a method to modify the existing constitutive equation of the macro-NPR bolt was proposed in this work, and the modified constitutive equation of the macro-NPR bolt was established to explore the key factors of the macro-NPR bolt to achieve high constant resistance and large deformation characteristics. During static tension, the stress state of the macro-NPR bolt was divided into two stages, an elastic stage and a constant resistance stage. For the constant resistance stage, the stick-slip phenomenon occurred between the cone and the sleeve, whereas the axial force of the macro-NPR bolt was basically constant around P0. Then, using the theory of elasticity and the climbing angle theory, the stress state of the macro-NPR bolt sleeve during tension was solved, and a mathematical expression of constant resistance of the macro-NPR bolt was obtained. Finally, the modified constitutive equation of the macro-NPR bolt was established through the corresponding expression and stick-slip element.

Large deformation characteristics and controlling measures of steeply inclined and layered soft rock of tunnels in plate suture zones

To clarify the inducing factors and mechanisms of geological disasters, such as large deformation and tunnel collapse, tunnels with layered and soft rock in the Luang Prabang suture zone were examined in this paper. Based on an investigation and summary of the disaster characteristics of tunnel deformation, the excavation loosening zone and geo-stress conditions were field-tested by using a sonic detector and a hollow inclusion strain gauge to analyse the correlation between the surrounding rock deformation and the extent of the excavation loosening zone and geostress distribution. The results show that, influenced by the Luang Prabang geological suture zone, underground water and the mechanical characteristics and occurrence of the rock mass, the surrounding rock mass deformation presents obvious asymmetric features. A large deformation of the rock mass more easily occurs at the tunnel crown and right spandrel (waist), and the main deformation phenomena are the spalling and cracking of shotcrete, buckling and bending of the steel arch and large horizontal convergent deformation. According to the sonic velocity monitoring of the rock mass, the scope of the excavation loosening zone of the rock mass is approximately 5.5 m to 7 m, which is beyond 60% of the tunnel width. Based on the field geostress test, the tunnels in plate suture zones bear intensively horizontal tectonic action, and the maximum lateral pressure coefficient of three tunnels is more than 1.5 (σ1/σ3). Thus, the horizontal convergence deformation and supporting structure failure of the tunnel are serious. Some controlling measures were adopted to release and control rock mass deformation, such as improving the advance support structure, enhancing the steel arch strength and increasing the allowed deformation of the rock mass. Moreover, asymmetric support design, such as local borehole grouting and temporary horizontal support structures, also be implemented. Additionally, the optimal design of rock bolt installation and grouting reinforcement depth should be given more attention during tunnelling.

Study on supporting time of tunnel lining in thin-layered rock mass

The thin-layered rock mass of Baokang tunnel has the characteristics of large deformation and failure of soft rock under the excavation unloading. More seriously, a serious question is that the lining cracking is prominent. The cause of the cracking can be traced to different failure modes of the surrounding rock mass. Specifically, the rock layer on left arch spandrel is prone to bending failure due to the action of tangential stress, while the right-side wall is prone to sliding failure due to the action of higher shear stress. Furthermore, the lining cracking may beyond the ultimate compressive capacity when the loosely collapsed rock mass acted on the lining. According to the transversely isotropic characteristics of layered rock mass, the failure approach index (FAI) was selected to evaluate the damage and failure of thin shale. Meanwhile, the result of the example shows that this index can effectively characterize the failure characteristics of the thin-layered rock mass. Hence, the FAI was used as an evaluation index of the loose failure of layered rock mass. In order to determine the lining support time, the stability of the lining under the action by the loose rock mass was analyzed by the numerical simulation. As a result, the distance between the lining and the face should not be bigger than 120m. According to the Feedback through onsite construction, the lining cracks didn’t appear under this supporting time, which ensured the stability of the lining structure. The research methods and ideas can provide reference for the similar tunnel lining construction in thin-layered rock mass.