Study on Excavation Damage Characteristics of Surrounding Rock in Deeply Buried Tunnels by Particle Flow Code Simulation

This study is aimed at investigating the excavation damage characteristics of surrounding rock in Jinping deeply buried marble tunnels, China. According to acoustic detection results tunnel cross-sections under condition boring machine (TBM) obtained on site, PFC microscopic parameters Types II/III were simulated and calibrated through PFC2D program. In doing so, deeply-buried sections diversion tunnels simulated. The reveal that zones (EDZ) are unevenly distributed around tunnels; largest zone located from top arch north shoulder. EDZ depth degree rise with increase depth, they also decrease quality. Generally, maximum Type III about 1.0 m larger than II same which basically consistent relaxation rock. simulation well discloses tunnels.