Generally, the pervasive joint model in FLAC3D and the
simulation calculation using MohrCoulomb strength criterion are
used to evaluate the stability of rock accurately. However, the layered rock
mass is essentially regarded as isotropic, leading to a large error between
simulated results and monitoring values. Based on a revised HoekBrown criterion, the instantaneous equivalent and best onetime approximation are performed on the I1-J2 plane and MohrCoulomb strength criterion,
respectively, and the corresponding equivalent strength formula is derived. The
formula is used to calculate the equivalent strength parameters of rock masses
with different inclination angles, and the FLAC3D pervasive joint model is
imported to study the stability of the surrounding rock in the Gonghe tunnel of
the ChongqingHunan expressway. The results show the
following. (1) The methods are used for modifying the rock mass parameters. The
deformation of key points after the tunnel excavation is greater than that
before the modification, which is closer to the measured value. (2) The value
of deviatoric stress σ1-σ3 obtained from the instantaneous
equivalent modification is smaller than that before the modification. The value
of σ1-σ3 obtained from the best onetime approximation modification is greater than that before the
modification, and the change in trend with inclination is the same as that
before modification. (3) The instantaneous equivalent modification and best onetime approximation modification methods can be used for rock mass
parameter modification; the latter one has a better effect.
HU Qizhi
,
LIU Qian
,
DING Zhigang
,
BAO Wencheng
.
Comparison and Application of Strength Equivalent
Methods Based on Hoek-Brown
Criterion
[J]. Tunnel Construction, 2021
, 41(10)
: 1662
-1671
.
DOI: 10.3973/j.issn.2096-4498.2021.10.005
