Peat soil exhibits significant creep deformation, and its consolidation law differs from that of soft soil. This study examines the strain characteristics of peat soils during three stages of consolidation using indoor one-dimensional creep consolidation tests. The results showed that the rebound deformation after the primary consolidation stage and the secondary consolidation stage is equivalent to the deformation seen during the primary consolidation stage, about 1.003 times. However, once the deformation stabilizes, the rebound deformation decreases to 0.32–0.85 times that of the deformation observed during the primary consolidation stage. The elastic and time-independent plastic strains of the peat soil showed two-stage linear changes with ${\ln \mathsf{\sigma }}_{\mathrm{z}}^{\prime }$. When the load was greater than the pre-consolidation pressure, the deformation modulus increases by approximately 2.10 and 1.56 times, respectively. On this basis, this study, for the first time, defines the creep rate according to the strain rate in the tertiary consolidation stage in the strain versus the time curve (${\epsilon }_z~t$). Based on the timeline, a one-dimensional creep consolidation model is established that can accurately predict the strain during the consolidation of the peat soil foundation. The results reveal distinct strain behaviors during each stage and improve the theoretical basis for the study of creep.

Extreme rainfall events pose a growing threat to slab track subgrades by triggering mud pumping through fines migration and structural voids. This study introduces two innovations to enhance climate resilience in high-speed railway infrastructure: (i) the Rain Intensity Ponding (RIP) method, which links regional rainfall statistics with axle-pass thresholds to predict mud pumping potential; (ii) an optimized drainage retrofit using permeable shoulders and blind ditches. Physical model tests reveal that mud pumping occurs only when structural gaps, ponding, and cyclic loading coincide. The RIP method correctly identified a 71% exceedance in the critical ponding duration (52 min) on a representative high-speed line in Eastern China, explaining recurrent failures. Parametric analyses show that the proposed drainage retrofit—using shoulder fill with ka > 23 mm/s and blind ditches with kg > 23 mm/s—reduces ponding time by up to 90% under 1-year recurrence storms. This study establishes a physics-based, region-specific strategy for mud pumping mitigation, offering guidance for climate-adaptive slab track design and operation.

Locally available rock salt is a potential fill material for infrastructure construction in arid salt-lake regions, where conventional soil and aggregate resources are often scarce. However, its mechanical performance is strongly affected by water migration, brine concentration, salt dissolution, and possible recrystallization-induced bonding. This study investigates the unconfined compressive strength (UCS) of compacted rock-salt fills under different water contents, initial brine contents, relative compaction levels, and brine concentrations. The results show that UCS increases nonlinearly as water content decreases during air drying, with slow strength development at the early drying stage followed by rapid strength gain at low water contents. This behavior is consistent with a transition from capillary liquid bridges to stronger salt-related interparticle bonding during brine evaporation and possible recrystallization. The effect of initial brine content is state-dependent: higher initial brine content reduces UCS in the as-compacted state but markedly increases UCS after drying to constant mass, suggesting enhanced interparticle bonding after drying. Under constant-mass air-dried conditions, UCS first increases and then decreases with increasing relative compaction, reaching a peak of approximately 8.7 MPa at a relative compaction of 0.99. Lower brine concentration reduced the UCS of dried specimens, indicating that saturated brine may be more favorable for specimen preparation and field compaction under dry salt-lake conditions. An empirical UCS prediction equation incorporating water content, dry density, initial brine content, and brine concentration was developed and validated, giving good agreement with the test results with R² = 0.91. The findings provide a material-level basis for evaluating and controlling compacted rock-salt fills under controlled dry conditions, while further durability and field validation are required before extending the results to long-term railway subgrade performance.