Study on macro–micro mechanical behavior of broken rock mass using numerical tests with discrete element method

Generally, there is broken rock mass in surrounding rock of deep underground engineering, whose macroscopic mechanical properties are very important for engineering stability. In this paper, the triaxial numerical tests of broken rock mass are carried out by using discrete element software. According to the results of numerical tests, the microcrack evolution process of broken rock mass can be divided into five stages, and the number of tensile cracks is more than that of shear cracks during the whole process. The microcracks in broken rock mass are mainly distributed on the weak structural plane between internal rock blocks. The microcracks number of broken rock mass decreases with the increase of their azimuth. According to acoustic emission test results of cemented waste rock backfill with poor cementing whose structure is as similar as that of broken rock mass, the numerical results are verified. Finally, the influence of rock block shape and rock block size on the macro–micro failure mechanism of broken rock mass is studied.