隧洞开挖重复爆炸荷载作用下围岩累积损伤特性

发布时间：2018-12-11 03:01

【摘要】：隧洞毫秒爆破开挖推进过程中,预留岩体在重复爆炸荷载作用下产生不可逆的损伤叠加。而现有的岩体爆破损伤数值模拟基本都是针对单孔装药和单段爆破,很少涉及实际工程中的重复爆炸。基于LS-DYNA程序的用户自定义材料接口,将统计损伤演化模型嵌入到弹塑性本构材料中,模拟圆形隧洞全断面毫秒爆破过程中重复爆炸荷载作用下的岩体累积损伤效应,并考虑地应力对岩体爆破损伤的影响。计算结果表明,围岩损伤范围和损伤程度随重复爆炸荷载次数而增加,在一个爆破进尺内,围岩损伤的临界峰值质点振动速度较单段爆破降低了12%;爆炸荷载作用下,围岩主要表现为拉损伤,围岩地应力对爆破张拉效应起到非常敏感的"抑制"作用,在2~10 MPa应力水平时,围岩爆破累积损伤范围随着应力增加而明显减小,围岩损伤的临界峰值质点振动速度增加24%~57%。
[Abstract]:During the excavation of tunnel by millisecond blasting, there is irreversible damage superposition of reserved rock mass under repeated explosion load. However, the existing numerical simulation of rock mass blasting damage is mostly aimed at single hole charge and single stage blasting, and rarely involves repeated explosion in practical engineering. Based on the user-defined material interface of LS-DYNA program, the statistical damage evolution model is embedded into the elastic-plastic constitutive material to simulate the cumulative damage effect of rock mass under repeated explosion load during the millisecond blasting of a circular tunnel. The effect of in-situ stress on blasting damage of rock mass is considered. The results show that the damage range and damage degree of surrounding rock increase with the number of repeated explosion loads, and the critical peak particle vibration velocity of surrounding rock damage decreases by 12 times compared with that of single blasting in a blasting advance. Under explosive load, the surrounding rock is mainly characterized by tensile damage, and the in-situ stress of surrounding rock plays a very sensitive "restraining" role to the tensile effect of blasting. At the stress level of 2 ~ 10 MPa, the cumulative damage range of surrounding rock decreases obviously with the increase of stress. The critical peak particle vibration velocity of surrounding rock damage increases by 24%.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;武汉大学水工岩石力学教育部重点实验室;
【基金】：国家重点基础发展规划计划(973)项目(No.2010CB732003) 国家自然科学基金资助项目(No.51125037,No.51279135,No.51179138) 武汉大学博士研究生学术新人提名奖资助项目(No.T2011206009)
【分类号】：U451.2

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