爆破作用对层状顶板接触层面累积破坏效应分析

Analysis of Accumulated Damage Effects on the Layer Contact Level of Roof under Blasting Vibration Waves

露天井下联合开采矿山地面的爆破开采作业产生的爆炸应力波对浅埋采空区顶板及其围岩形成动力加载环境,从而造成采空区层状顶板接触面层的离层错位破坏,当这种破坏累积到一定时刻将可能诱发采空区失稳。利用FLAC3D构建采空区三维数值计算模型,采用其内置Interface命令模拟层状顶板的接触面层。在采空区顶板顶部输入安太堡露天矿实测的爆破波速度时程模拟爆破震动对采空区层状顶板的动力加载。通过分析设置监测点的位移曲线、接触面层的剪切应力场、法向应力场及贯入量值场的变化规律,揭示了随着爆破次数的增加及顶板厚度减小工况下,爆破作用对层状顶板接触面层的离层错位累计破坏效应,为类似采空区层状顶板的稳定性评价、失稳可能性的风险评估及露天爆破开采作业提供一定的技术参考。

The blasting mining operations on combined mining of open-pit mine mining area,which produce the explosion stress wave will formation dynamic loading on the goaf roof and surrounding rock,and it will cause layered roof of mined-out area delamination and dislocation damage,when the cumulative damage to a certain moment may cause instability of mined-out area. FLAC^(3D)was used to build a three-dimensional numerical calculation model and use its built-in interface command to simulation the layered roof of contact level. Input AN Tai Pu open-pit mine blasting wave velocity time history curve to simulate blasting vibration load on the mined-out area of layered roof.Through the analysis of the displacement curve of monitoring points and the change rule of shear stress field,normal stress field and penetration field of contact surface,it is revealed that with the decrease of the roof thickness and increase of number of blasting effect the layer contact level roof of mined-out areas accumulated damage effects,for similar mined-out area of layered roof stability evaluation and instability of the possibility of risk assessment and openair excavation blasting operation safety construction provide a technical reference.