To investigate the asymmetric deformation and stress characteristics of tunnels and support structures in high geostress layered fractured rock, this paper establishes two refined modeling methods: a numerical model for anchor bolt failure and a model for fractured layered surrounding rock, while considering the spatial variability of soil. The study analyzes tunnel deformation and bolt tensile-shear fracture mechanics under varying bedding angles. The results indicate that: (1) the most unfavorable stress position for tunnel structures in layered fractured rock typically occurs normal to the bedding planes; (2) the tunnel's asymmetric deformation is due to normal compressive and tangential sliding effects of geostress on the bedding planes. When the bedding angle is gently inclined, significant extrusion deformation occurs at the tunnel crown and invert; when steep, substantial tangential sliding forces cause maximum deformation at points where the bedding direction is tangent to the tunnel profile. (3) Fracture development in the surrounding rock primarily occurs normal to the foliation planes, similar to maximum displacement deformation patterns, while other areas propagate outward due to joint shear slip. (4) In layered fractured rock, failed bolts predominantly show tensile-shear fractures, influenced by bedding angle, particularly near the left shoulder to the crown and right invert. Finally, based on the deformation characteristics of layered fractured surrounding rock and the mechanical properties of anchor rod fracture, reasonable differential support optimization measures were proposed, and the simulation results were applied to the Yangjiaping Tunnel of the Chenglan Railway in China.

The long-term safety and durability of anchor systems are the focus of slope maintenance management and sustainable operation. This study presents the observed temperature, humidity, and anchor bolt stress at varying depths from four-year remote real-time monitoring of the selected loess highway cut-slope. The potential correlation between slope hydrothermal environment and anchor stress is analyzed. The anchor serviceability and durability were evaluated by establishing a time-dependent mathematical model of axial forces. The results show that the slope shallow loess exhibited hydro-thermal fluctuations annually during operation, subjecting the loess to continuous dry-wet cycles. Soil elastic deformation induces anchor axial force fluctuations due to hydro-thermo effects, while damage creep leads to the annual increase in axial force peaks and valleys. The increase in axial force is more significant at the upper slope and lower slope, thereby increasing the risk of retrogressive landslides in loess slopes. The time-dependent model of anchor axial force composing negative exponential and sine functions was proposed. The cyclic amplitudes, lower limits, and periods of temperature and humidity in slope can determine the model coefficients. The development patterns of axial force are classified into stable type, slow growth type, and accelerated growth type according to the characteristics of the model coefficients. Predicted results indicate that the anchor axial forces are lower than the landslide threshold within 30 years of slope operation, ensuring long safety and serviceability. Results provide a reference for the long-term safety evaluation and formulation of maintenance plans for loess slopes reinforced by anchor systems.