Mechanical response and pore pressure evolution of cemented paste backfill under deep mine-like multiaxial stress and temperature conditions

• Multiaxial stress enhances CPB strength and stiffness by promoting denser particle packing and increasing frictional resistance. • Elevated temperatures accelerate early-age cement hydration, improving bond strength and stiffness. • Combined multiaxial stress and elevated temperature synergistically enhance UCS and elastic modulus, confirmed by two-way ANOVA and synergy index analysis. • Pore water pressure evolution is governed by thermal expansion, hydration-induced desaturation, and mechanical compaction, with a transient 'stress-induced resaturation' effect mitigated by elevated temperatures.