摘要
基于围岩开挖爆破主频率衰减过程定义损伤变量,得到围岩爆破损伤量随爆心距变化的函数关系式;通过围岩爆破损伤量与爆心距函数关系曲线变化规律以及围岩破坏特征总结得出围岩损伤破坏的5个区,分别为:围岩粉碎区、碎裂区、破裂区、后续损伤区(扰动区)和原岩区,并得出对应的分界损伤变量、爆心距以及围岩损伤范围。以龙滩水电站右岸导流洞爆破开挖工程为例,计算结果表明:龙滩水电站右岸导流洞爆破开挖引起的岩体损伤量是爆心距的递减函数,损伤范围依次为0.5 m、0.59 m、3.16 m、8.25 m,损伤范围依次增大,增长率先增大后减小,如粉碎区到碎裂区增长率为15.3%,碎裂区到破裂区为81.3%,破裂区到后续损伤区为61.7%。围岩损伤在破裂区变化最快,此范围内爆破应力波能量衰减急剧,粉碎区、碎裂区、后续损伤区以及原岩区损伤变量随爆心距缓慢递减。实例表明,此损伤分区计算方法具有可靠性。研究成果对于有效评估地下工程施工围岩损伤特性及分析隧洞开挖优化设计具有积极意义。
Based on the main blasting frequency attenuation process of surrounding rock excavation,the damage variable was defined and the function of the damage variable changing with the blasting center distance was obtained. Five damage zones were found with the function of the damage variable changing with the blasting center distance and surrounding crack characteristics,they were smash zone,fragmentation zone,fracture zone,subsequent damage zone（ disturbed one） and original rock zone. In addition,the corresponding critical damage variable,the blasting center distance and the damage scope of five damage zones were obtained. Taking the blasting excavation engineering of the diversion tunnel of the right bank of Longtan hydropower station as an example,the calculation results showed that the amount of rock damage arising from blasting excavation of diversion tunnel is a decreasing function of the blasting center distance,and the damage scopes are 0. 5m,0. 59 m,3. 16 m and 8. 25 m,respectively,with an increasing tendency but the growth rate increases firstly and then decreases; for instance,the growth rate of smash zone to fragmentation zone was15. 3%,81. 3% for fragmentation zone to fracture zone,and 61. 7% for fracture zone to subsequent damage zone;surrounding rock damage rate changes the fastest in fracture zone,in this zone the blasting stress wave energy decays rapidly; the damage variables of fragmentation zone,fracture zone,subsequent damage zone and original rock zone decrease slowly with the blasting center distance. The actual example showed the reliability of the proposed method. The study results had a positive significance for evaluating surrounding rock damage character effectively and analyzing optimal design of tunnel excavation.
出处
《振动与冲击》
EI
CSCD
北大核心
2015年第23期202-206,共5页
Journal of Vibration and Shock
基金
国家自然科学基金(51378521)
重庆市国土重大科技项目(CQGT-KT-120301)
关键词
地下工程
围岩
损伤分区
施工爆破
underground engineering
surrounding rock
damage zone
construction blasting
作者简介
唐红梅 女，博士，研究员，1968年生
