Experimental Study On Rock Mechanical Properties Under Freezing Conditions And Application In Project

Along with the increase of coal demands, the construction of mine develops gradually deeper and deeper, The artificial freezing method is a effective method in constructing the shaft in the deep surface soil or the rock, In the freezing process of shaft construction, we meet not only the deep soil layer, but also the rock layer containing much water in recent years, In this area, the fundamental theory and the experience are quite defective. Developing the experimental study of artificial freeze rock, and discussion about physical and mechanics characteristic of freezing rock, have the important guiding sense to the shaft freeze design.This article takes the Hu Jia river coal mine vertical shaft freezing project in Shanxi BingChang mining area as a background, has selected two kinds of typical rocks, the coal and the sandstone, carries on a systematic single axle, three axle compressing experiment. Through the experiment, we have analyzed the mechanics characteristic and the distortion characteristic of the coal and the sandstone in the different freezing temperatures or under the different stressful condition, and analyzed the identity and the difference between the two rock.. Based on this analysis, we have studied the size and the change rule of the two rock in single axle compressive strength, the elasticity coefficient and the Poisson ratio under the different low temperature. In the three axle compressing experiment of the sandstone, we have discussed the relationship between the three axle compressive strength with the encircle presses and the temperature. Based on this discussion, through the Mohr-Coulomb criteria, we have elicited the relationship between the cohesive strength and the internal friction angle with the encircle presses and the temperature under the different low temperature.After analyzing the definite method of the out-load on the freezing wall and the method in designing the thickness of the freezing wall in domestic and foreign areas. linking to the Hu Jia river coal mine freezing project reality, taking the elastic-plasticity theory as the foundation, we have used the formula which under the unloading condition in freezing wall. Calculated and Analyzed the freezing wall's thickness, active status and out-load of the host and auxiliary shaft. Regarding certain guiding sense to the freezing wall's design .