Abstract: In this paper, a series of triaxial compression experiments was performed to investigate the effects of fracture dip, trace length, gap width, confining pressure and temperature on mechanical properties of the single-fractured rock mass. Experimental results show that the mechanical parameters of rock mass exhibit the quadratic function with dips and the exponential distribution with trace length, respectively. Moreover, the fitting formula (3) is employed to calculate rock mass strength approximately. It is found that rock mass strength linearly increases with the confining pressure. However, Poisson ratio and elastic modulus under negative temperature are independent of the confining pressure. The strength of rock mass decreases with the increase of gap width when it is less than 0.1 mm or greater than 0.8 mm. However, mechanical parameters are irrelevant to the gap width when it locates between 0.1 mm and 0.8 mm. Water, existing in pores and fractures, freezes under negative temperature so that both the cohesion and friction angle between rock particles are increased. Hence, the change of water form is the reason why the rock mass strength increases with reducing temperature. Results also show that the fracture angle affects the initial position of failure surface, the trace length affects the expansion scale of failure surface, and the confining pressure influences the extension direction of failure surface. In addition, the crack dip is the most sensitive influencing parameter to the strength of rock mass, followed by trace length, with the least temperature.

Key words: single-fractured rock, fracture morphology, frozen temperature, mechanical properties