Creep mechanical properties of sandstones under triaxial compression with different loads and water contents

• Compressive strength, creep failure stress, and dilatancy stress of sandstone decrease exponentially with increasing water content and increase exponentially with confining pressure. • Lateral creep strain is more significant than axial, and lateral strain enters steady-state creep earlier, with accelerated creep onset occurring earlier laterally under failure stress. • Long-term strength of sandstone shows a negative exponential relationship with water content and a positive exponential relationship with confining pressure, determined via lateral steady-state creep rate. • A novel method for determining long-term strength based on the lateral-to-axial strain ratio (μc) is proposed, independent of water content, aiding in early creep failure prediction.