震动作用下采空区上方地基稳定性

Stability analysis of foundation above abandoned golfs under seismic action

为深入探讨废弃采空区在震动作用下二次活化机理及其变形破坏规律,通过数值模拟的方法分别探讨煤层开挖相对稳定后,上覆围岩跨落变形后无离层和存在离层两种情况在地震波的作用下,废弃采空区上覆围岩但稳定性.模拟结果表明:采空区在经过地震作用下,上覆岩层应力发生了重新分布.在采空区两边界出现应力集中现象.离层模型在应力和位移上明显比无离层模型要大的多,说明废弃采空区离层上覆岩层受到地震力扰动后更容易发生"活化",但离层模型和无离层模型在地震波作用下各观测点的应力值随时间变化而变化其动应力时程表现为波动曲线其波动周期与输入加速度的周期一致,顶板动应力来说其的分布规律与重力静力作用下的应力分布规律具有很多相似之处.

In order to discuss the secondary activation mechanism and the regular pattern of deformation and failure of abandoned goafs under the actions of earthquakes,this paper,by means of the numerical simulations,studied the stability of overlying rock after reaching the excavation relatively stable condition under the action of seismic wave.The simulation results show that the overburden stress redistribution happened after the earthquake and the stress concentration phenomenon occurred in the two boundaries of mined-out areas.The stress and displacement of delamination model is more obvious than that of the no delamination model,which explains that the overlying rock of abandoned goafs are more likely to have the "activation" under seismic force;but no delaminating of the abscission layer model and the model under the action of seismic wave stress value of each observation point changes over time,and the dynamic stress time history of volatility curve and the cycle is consistent with the input acceleration period.The dynamic stress distribution of roof and the static stress distribution law under the action of gravity have many similarities.