【摘要】 深埋隧洞爆破开挖过程中,爆炸荷载和地应力的共同作用是造成围岩损伤的主要原因,威胁到岩体工程的安全。首先在原有裂纹分形模型基础上,引入最大拉应力理论和应变能密度理论作为联合判据,同时考虑岩体拉伸和压缩损伤对围岩参数的劣化影响,建立适合于高地应力条件下的爆破开挖拉-压剪损伤本构模型。然后将模型成功嵌入到动力有限元数值分析中,对锦屏水电站引水隧洞爆破开挖损伤效应进行动力计算,并与实测数据进行对比。在此基础上研究了相同地应力环境下,不同爆炸装药条件对围岩损伤的影响规律。结果表明:岩体损伤区中,内损伤区损伤程度大,主要受爆炸荷载拉-压剪联合损伤作用;外损伤区,损伤程度相对较轻,主要受地应力影响。当爆炸荷载达到一定量级后,随着爆炸荷载的增大,围岩的损伤区先快速增大,然后增速减缓,但内外损伤区的差值,则是先减小后增大。更多还原

【Abstract】 In the process of blasting excavation of deep submerged tunnel,the combined action of blast load and in-situ stress is the main cause of the damage on surrounding rock,which makes great threat to the safety of rock mass engineering. First of all,in the original basis of crack fractal model,the maximum tensile stress theory and strain energy density theory were introduced as a united criterion,at the same time,by taking into account the influence of rock tensile and compressive damage on the parameters of surrounding rock,the tension-compression-shear damage model was established for the excavation blasting in the high in-situ stress conditions. Then,the model was successfully linked to the dynamic finite element analysis,and the dynamic calculation of the damage effect in surrounding rock of blasting excavation for diversion tunnel of Jinping hydropower station was carried out. By comparing with the measured data,the model validity was tested. With the same numerical simulation,the damage bahavior of surrounding rock under different explosive charge conditions was studied in the same in-situ stress environment. The results show that the damage zone was divided into two types,as outer damage zone and inner damage zone. The damage degree was larger in the inner damage zone,which was mainly influenced by the tension-compression-shear damage of the explosion load. However,outer damage zone is relatively lighter,which is primarily subjected to the in-situ stress.When the explosion load reached a certain level,the damage zone of remaining rock increased rapidly with the blast load increasing,and then the growth rate decreased. While the difference value between outer damage zone and inner damage zone was firstly decreased and then increased.更多还原