The laboratory mechanical test is carried out on
limestone of Tongzi Tunnel on LanzhouHaikou Highway, and the
numerical simulation of loading and unloading rockburst test is carried out by
threedimensional particle flow program particle flow
code（PFC）, which helps to
obtain the meso failure characteristics of rock samples under different stress
states. The results show that: (1) The rock stress variation, particle
displacement, bond failure characteristics and energy variation of rock during
loading test show 3 stages, i.e. elastic stage, yield stage and failure stage.
(2) With the increase of initial stress, the loading strength of rock
increases, and the ultimate strain of rock increases. (3) The greater the
stress, the greater the rockburst strength during the unloading test, resulting
from stress concentration inside the rock induced by the stress transfers from
the unloading surface to the interior during rock failure; with other
conditions unchanged, the higher the initial stress, the greater the unloading
rockburst strength; and the increase in radial stress will have a more adverse
effect on the stability of the chamber rock. (4) The failure modes of rock
under loading and unloading conditions are quite different.
CAI Jun, REN Zhenggang, WU Yunjie, SHEN Yupeng, LIU Yue
. Numerical Simulation of Loading and Unloading
Rockburst Failure Characteristics Based on PFC3D[J]. Tunnel Construction, 2020
, 40(S1)
: 98
-106
.
DOI: 10.3973/j.issn.2096-4498.2020.S1.013
