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Microwave-assisted crushing and grinding can improve efficiency and reduce energy consumption. This paper takes rock grains with galena and calcite as the research object to establish a two-dimensional computational model through the finite difference software FLAC2D. It analyzes the process and law of mineral boundary failure under microwave irradiation, and assesses the effects of four factors, namely, microwave irradiation time, power density, mineral crystal size, and mineral content, on mineral boundary failure. Results indicate an optimal microwave irradiation period for the rapid failure of mineral boundary. Moreover, irradiation time and energy consumption can be reduced by increasing the microwave power density. However, irradiation time and energy consumption are basically unchanged when the microwave power density is above a certain threshold. Mineral content slightly affects the microwave irradiation time, whereas mineral crystal size significantly affects the microwave irradiation time. In addition, a larger-sized mineral crystal requires less irradiation time and energy consumption to reach the same failure rate. However, irradiation time and energy consumption slightly change when the crystal size is larger than a certain value.

In order to make model loading plan reasonably, point loads and moving loads are used in the finite element calculation model of subway tunnel, and the result shows that: the time-history curves of acceleration are uniform under two conditions of point loads and moving loads in the U-shaped Metro tunnel orthogonal with the ground fissure, and they are consistent with the load curve. Under two conditions of point loads and moving loads, the maximum displacement along the tunnel arch bottom are at the end of the tunnel and the minimum displacement are at the middle. In these two conditions, the distributions of the displacements are agreement. The vertical acceleration of lining arch bottom has much difference with the loading frequencies changed. In point load conditions, the maximum acceleration curve of 3Hz, 8Hz take on inverted V shaped and the maximum acceleration curve of 5Hz, 10Hz, 15Hz and 20Hz take on a V shape; in moving loads case, the maximum acceleration curve of 5Hz is inverted V shaped; the maximum acceleration curve of 20Hz is V shaped; the maximum acceleration curve of 8Hz is lower left upper right; and the maximum the acceleration curve of 10Hz and 15Hz are upper left lower right.