Abstract: In order to analyze the influence of surrounding rock temperature and humidity on the micro pore structure characteristics and uniaxial compressive strength of shotcrete, indoor CT scanning and unconfined compression test are carried out, and the prediction model of uniaxial compressive strength of shotcrete is established based on micro structural parameters. The results show that: (1) Under the low humidity environment (with humidity of 25%), high rock temperature induces the deterioration of shotcrete pore structure and mechanical properties, and the higher the temperature, the more obvious the effect of deterioration; the uniaxial compressive strength of shotcrete is predicted by Schiller model. (2) Under the high humidity environment (with humidity of 95%), 60 ℃ rock temperature is the critical temperature for deterioration of mechanical properties and pore structure characteristics of shotcrete. (3)The prediction model of compressive strength of shotcrete in high humidity environment is established by introducing the influence coefficient of relative humidity, of which the prediction results are in good agreement with the test results.

Key words: tunnel, temperaturehumidity coupling, shotcrete; pore structure, compressive strength, prediction model