为准确评价大型地下洞室群的安全状态，探究基于局部强度折减方法的地下洞室群安全系数求解方法。将屈服接近度(YAI)小于0.1的区域定义为“危险区”，以洞室之间围岩“危险区”贯通作为洞室群整体破坏判据，将“危险区”贯通时对应的折减系数定义为洞室群破坏的安全系数，定量评价洞室群整体稳定性，解析各类洞室群破坏判据计算结果差异。研究结果表明： 1）各判据对应的安全系数从大到小依次为等效塑性应变贯通、塑性区贯通、关键点位移突增、“危险区”贯通； 2）以关键点位移突增为标准，另3种判据求出的安全系数误差分别为33.7%、13.9%、2.6%； 3）基于“危险区”贯通的安全系数计算结果与位移突增判据更为接近，以“危险区”贯通为破坏判据的破坏区与工程实际围岩的破坏特征相符合，计算量更少。
The method of solving the safety coefficient of an
underground cavern group based on the local strength reduction method is
investigated to accurately evaluate the safety state of large underground
cavern groups. A danger zone is defined as an area with YAI （yield
approach index） of less than 0.1. The danger zone
penetration of the surrounding rock between caverns is used herein as the
criterion for the overall damage of the cavern group. The discount factor
corresponding to the danger zone penetration is defined as the safety factor of
the cavern group damage. The overall stability of the cavern group is
quantitatively evaluated. Moreover, the differences in the calculation results
of the damage criteria of various cavern groups are analyzed. The results show
that: (1)The order of the safety coefficient of each criterion from large to
small is equivalent to plastic strain penetration, plastic zone penetration,
sudden increase in displacement at critical points, and danger zone
penetration. (2)According to the sudden increase in displacement at critical
points, the errors of the safety coefficients of the other three criteria are
33.7%, 13.9%, and 2.6%, respectively.
(3) The calculation result of the safety coefficient based on the danger zone
penetration is closer to that of the displacement surge criterion; moreover,
the damage zone based on the danger zone penetration is consistent with the
actual damage characteristics of the surrounding rock of the project. The
calculation volume is less.
