基于3DEC的结构面对采空区的影响机制

Influence mechanism of structural plane on goaf based on 3DEC

Ⅳ级结构面是构成岩块的边界面,影响着地下工程岩体的物理力学性质及应力分布状态。基于3DEC离散元软件,在特定的采空区应力场下,针对单组结构面以及多组结构面中可产生滑塌锥的情况分别开展了研究。结果表明:1)单组结构面对采空区的影响形式为滑移破坏,随着结构面倾角的增大,采空区顶板最大位移先增大后减小。2)多组结构面形成滑塌锥后并不一定意味着塌落,在黏聚力以及内摩擦角较大时滑塌锥仍然可以保持稳定;在黏聚力—内摩擦角—滑塌锥位移的三维曲面图中,形成稳定区、塌落区、滑移区三类。3)利用极限平衡理论对滑塌锥的稳定性进行力学分析,提出滑塌锥失稳的判定条件,具有一定的工程实用价值。

The structural plane which effects physico-mechanical propertiesandstress distribution of rock mass in underground Engineering is the boundary surface of rock mass.Under the specific stress field in the goaf,a stability research on the single group structures and multiple group structures which can produce the slump cone is carried out based on 3 DEC.The results show that（1）The influence form of single group structure on the goaf is sliding failure,with the increase of the angle of structure plane,the maximum displacement of the roof of the goaf increases first and then decreases.（2）Multiple group structure planes which can form the slump cone do not necessarily collapse,the slumpcone can still remain stable when cohesion and internal friction angle are large.3 D surface chart is made up of stable region,collapse zone,slump zone which include cohesion and internal friction angle and slump cone displacement.The internal friction angle of slump cone displacement is more sensitive than the cohesion.（3）By using the limit equilibrium theory to analyze the stability of the slip block,the judgment condition of instability of slump cone is put forward,which has a certain engineering practical value.