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研究岩体的临界破碎损伤阈值对于划分岩体的破碎状态和确定爆破岩体可开挖范围有重要意义。根据爆破作用过程和岩体破碎机制,分析钻爆条件下岩体的破碎状态,提出保留岩体与可开挖岩体的分界面处于一种临界破碎状态。基于岩体的声波特性和损伤理论,利用岩体损伤变量来表征岩体的破碎程度,并将岩体损伤分为初始损伤和爆破损伤。依托白鹤滩水电站工程项目,在坝肩爆破开挖区进行大量的声波测试试验,分析不同深度岩体的损伤状态,试验结果表明,爆后岩体临界破碎损伤变量在0.8左右。搜集国内外有关项目的声波实测数据,统计临界破碎状态岩体的损伤变量,并最终确定其损伤阈值为0.75~0.85。
It is of great significance to study the critical crush damage threshold of rock mass for the purpose of dividing the crushing state of rock mass and determining the excavated scope of blasting rock mass. According to the blasting process and the rock mass crushing mechanism, the crushing state of the rock mass under the condition of drilling and blasting is analyzed, and the interface between the retaining rock mass and the excavated rock mass is in a critical crushing state. Based on the acoustic characteristics and damage theory of rock mass, the rock mass damage variables are used to characterize the degree of rock mass crushing, and the rock mass damage is divided into initial damage and blasting damage. Relying on the Baihetan hydropower station project, a large number of acoustic tests were carried out in the blasting excavation area of dam abutments to analyze the damage status of rock mass at different depths. The experimental results show that the critical breaking damage of rock mass after explosion is about 0.8. The sounding data of relevant projects at home and abroad were collected and the damage variables of the rock mass in the state of critical crushing were counted. Finally, the damage threshold of the rock mass was calculated to be 0.75-0.85.