<p>Unconfined compression test data English.</p>

This study developed an integrated experimental-numerical-field framework to evaluate these effects for the Chaoyang open-pit coal mine in Heilongjiang Province, China. Unconfined compression and direct shear tests were conducted under four moisture contents of 14.0%, 17.6%, 23.0%, and 26.0% and three temperatures of 23 ± 2°C, −5°C, and −15°C. The measured elastic modulus, cohesion, and internal friction angle were incorporated into a three-dimensional GTS NX model to assess slope responses before and after 72 h of rainfall.At room temperature, increasing moisture content reduced the elastic modulus from 1802.4 to 1003.6 MPa and cohesion from 18 to 10 kPa, while the pre-rainfall factor of safety decreased from 1.405 to 1.176.

Under subzero conditions, stiffness and cohesion increased because of pore-ice bonding, whereas the internal friction angle varied only modestly and non-monotonically. At −15°C, the post-rainfall factor of safety ranged from 1.478 to 1.537, and rainfall-induced reductions under all subzero conditions remained below 0.60%. Under the room-temperature natural-moisture condition, drainage pipes increased the factors of safety before and after rainfall from 1.221 and 1.184 to 1.413 and 1.384, respectively.