循环爆炸作用下地下洞室的动态响应及损伤累积

为研究循环爆炸对地下洞室的影响,基于相似模型试验,采用通用有限元软件ABAQUS对比研究了洞室拱顶高水平单次爆炸和低水平10次循环爆炸作用下地下洞室围岩的应力波衰减规律、损伤累积规律及洞壁位移和环向应变分布特征。结果表明:循环爆炸中,洞室围岩的应力波衰减速度随着爆炸次数的增加先减小后增大。单次爆炸中,洞壁环向峰值应变从拱顶至直墙脚由拉应变转为压应变;循环爆炸中,随着爆炸次数的增加,拱顶环向峰值应变由压应变转为拉应变。爆炸荷载总水平相同时,低水平循环爆炸中洞室围岩的损伤面积和程度比高水平单次爆炸大。循环爆炸中,围岩的损伤累积呈现不可逆的逐级增加趋势,且累积损伤和爆炸次数之间呈明显的非线性关系。

Dynamic Responses and Cumulative Damage of the Underground Cavern under Cyclic Explosion

To assess the effect of cyclic explosion on underground caverns,based on a similarity model test,the finite element software ABAQUS was utilized to analyze the dynamic responses and cumulative damage of underground caverns under cyclic explosion at low levels and a single explosion at high level.The stress wave attenuation characteristics and the cumulative damage evolution laws of the surrounding rock were presented.Besides,the displacement of the vault and the circumferential strain of the cavern wall were compared and analyzed.The results indicate that,with the increase of explosion times,the stress wave attenuation speed of the surrounding rock under cyclic explosion decreases first and then increases.In the single explosion,the peak circumferential strain of the cavern walls changes from tensile strain to compressive strain from the vault to corner.In the cyclic explosion,the peak circumferential strain of the vault changes with the increase of explosion times from compressive strain to tensile strain.Under the same explosion loading in total,the damage of the surrounding rock is greater in the low-level cyclic explosion than that in the high-level single explosion in terms of area and degree.In addition,the cumulative damage of surrounding rock under cyclic explosion presents an irreversible and step-by-step increase,and shows a dramatic nonlinear relationship with explosion times.