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Experimental Analysis on the Mechanical Properties of Saturated Silty Mudstone under Frozen Conditions

The mechanical properties (compressive peak strength and axial strain at peak strength) of frozen saturated silty mudstone are key parameters for the safety assessment of coal mine shafts during construction. However, the experimental data on such mechanical properties are limited. In order to derive much more accurate and economic results, in the present study, a series of uniaxial compressive tests were conducted on frozen saturated silty mudstone using temperature conditions of −10°C, −15°C, −20°C, and −25°C and loading rates of 0.2, 0.4, 0.6, and 0.8 MPa/s. The analysis of a number of experimental results showed that the compressive peak strength of saturated silty mudstone was related parabolically to temperature. On the other hand, the axial strain at peak strength was related linearly to temperature. The compressive peak strength of saturated silty mudstone was relatively small in comparison to saturated sandstone and saturated coal rock. Based on the experimental results, an empirical prediction model equation was established to describe the relationship between compressive peak strength, axial strain at peak strength, temperature, and loading rate, which will provide important reference values for mine shaft freezing construction when a water-bearing rock stratum exists.