(西南交通大学地下工程及岩土工程系,成都 610031)
摘 要: 在分析现有岩体爆破机理与块度计算模型的基础上,提出了考虑工程岩体的尺寸效应、将宏观结构弱面引入岩体爆破物理过程来建立块度模型的观点。为此,按照损伤力学的处理方法,应用连续介质损伤理论研究爆破过程中岩体弱面的破裂机制,给出了岩体沿节理破裂的损伤发展方程。从爆破岩块具有分形特征的思想出发,通过提出“岩体破裂比率” 概念,将爆破块度计算同节理岩体爆破机制相联系,建立起岩体爆破块度的损伤力学模型(BDM),该模型反映了岩体沿节理面破裂和岩石本身破裂的岩体爆破本质。
关键字: 节理岩体;爆破;损伤机理;块度
(Department of Underground Engineering and Geotechnical Engineering,
Southwest Jiaotong University, Chengdu 610031, P. R. China)
Abstract:Based on the analysis and discussion of both the mechanism of blasting in rock masses and the model of fragment-size calculation in existence, the viewpoint that the fragment-size model for blasting should take the dimension effect of engineering rock into consideration and introduce the macro weakness planes in rock masses into the physical process of blasting was advanced. According to damage mechanics, therefore, the original cracks in a rock mass can be treated as initial damage and the joints as a latent source of damage developing. The breaking mechanism of weakness planes in blasting process was studied by using the continuum damage theory and the developing equation of rock masses breaking along joints was deduced. Proceeding from the thought of blasted fragments having the fractal characteristics, the calculation of blasted fragment sizes was related to the mechanism of blasting in jointed rock masses by the new concept of "rock mass fracture ratio" presented and, thus, the model of damage mechanics for blasting in rock masses(BDM) was established, which reflects the blasting essence of both rock masses breaking along joint planes and rock breaking.
Key words: joint rock mass; blasting; damage mechanism; particle size