Abstract: Freezing method is an effective construction method to pass through the thickest alluvium in coal mine shaft construction. It is more necessary to study the mechanical properties in order to provide reasonable design parameters for shaft frozen sidewalls. Taking the frozen shaft project of Hujia River coal mine in Shaanxi Bingchang coal mine area as the project background, sandy mudstone of passing through the key shaft were obtained from the engineering site, the uni-axial compression tests and tri-axial compression tests were conducted under different frozen temperatures. The strength and deformation characteristics of sandy mudstone were analyzed of the same temperatures under the condition of different confining pressures and the same confining pressure in the condition of different temperatures. The result shows that the uni-axial strength and tri-axial strength of sandy mudstone increases with the freezing temperatures dropping. The main reason is mainly due to the peak intensity of sandy mudstone greatly improved by mineral contraction, ice strength and frost heave force with temperature decreasing.

Key words: sandy mudstone, freezing condition, mechanical properties, experimental study