## 5 Monitoring of Slope Displacements Under Freeze-Thaw Cycles  
To ensure comprehensive coverage of critical zones, an S-SAR trailer-mounted slope radar was strategically deployed on the elevation bench of 3548 m in the western mine slope, accounting for on-site power supply, network availability, and antenna coverage constraints. This system enabled real-time monitoring of the eastern slope. Six monitoring points were selected within the radar coverage area, corresponding to critical slope simulation zones. The geodetic coordinates and spatial distribution of these points are detailed in Table 6 and illustrated in Figure 12.  
The monitoring period was selected from 3 January 2021 to 3 January 2023 based on radar operational continuity. Displacement-time curves for the monitoring points  
\begin{table}
\begin{tabular}{c c c c} \hline
**Point** & **x** & **y** & **z** \\ \hline
1 & 401 & 310 & 3714 \\
2 & 397 & 307 & 3710 \\
3 & 391 & 301 & 3682 \\
4 & 386 & 296 & 3672 \\
5 & 380 & 290 & 3655 \\
6 & 372 & 284 & 3640 \\ \hline \end{tabular}
\end{table}
Table 6: Map of coordinates of observation points.  
Figure 11: Relationship between the safety factor and number of F-Ts.  
Figure 12: Cloud map of the radar monitoring area with observation points.  
are shown in Figure 13, revealing a progressive acceleration in deformation rates with prolonged freeze-thaw (F-T) exposure. The displacement evolution exhibited a triphasic \"stepped growth\" pattern:  
* Stage 1 was characterized by low deformation rates (<0.1 mm/day), minimal cumulative displacement increments, and negligible volumetric changes.
* Stage 2 demonstrated abrupt rate intensification (peaking at 1.2-1.8 mm/day) during annual June-September intervals. This period coincided with active F-T cycling in the slope, where water-ice phase transitions induced frost cracking and mechanical parameter degradation (cohesion reduction: 71.7-77.1%; friction angle decline: \(\sim\)52.0%). Superimposed gravitational and blasting vibration loads triggered pronounced displacement surges.
* Stage 3 displayed moderated deformation rates (0.3-0.6 mm/day) as pore water refreezing generated frost heave pressures, propagating fractures while destabilizing the slope. Despite residual displacement accumulation, the deceleration trend indicated partial stabilization under post-failure stress redistribution.  
The stepped growth pattern observed in field-monitored displacements exhibited similarities to numerical simulations but with notable discrepancies. This discrepancy arises from (i) the static F-T cycle representation in simulations (single damage state post-cycling) versus dynamic field conditions where cyclic damage progressively accumulates with annual F-T repetitions; (ii) temperature differentials between laboratory-controlled F-T minima (\(-\)40 \({}^{\circ}\)C) and actual field conditions (\(-\)25.6 \({}^{\circ}\)C), inducing divergent frost cracking intensities; (iii) oversimplified stress initialization in simulations (gravitational field only) neglecting transient loads from rainfall infiltration and blasting vibrations (PPV > 15 mm/s) during monitoring; and (iv) homogeneous F-T effect assumptions in models, disregarding spatial heterogeneity of freeze-thaw penetration depths (field-measured: 2.3 m avg.) and localized saturation variations.