Discrete Element Simulation and Monitoring Analysis of Different Construction Methods of the Shallow Buried Bias Tunnel

Figure 6

Distribution of contact forces of the three-step method: (a) distribution of contact forces for different excavation stages of the three-step method (without systematic bolt support); (b) distribution of contact forces for the final excavation stage of the three-step method: work condition 1 (A), work condition 2 (B).

(a)

(b)