Abstract
In the drilling and blasting excavation of underground rock mass, the stress wave produced by the blasting holes usually propagates in the form of cylindrical wave, while the rock mass surrounding the underground engineering is initially subjected to the in situ stress. To explore the propagation and attenuation law of cylindrical stress wave in the in situ stressed rock mass, a model test of cylindrical blasting stress wave propagation across the intact and jointed rock mass under different initial stresses was carried out. First, the attenuation law of the cylindrical stress wave in the intact rock mass under different confining pressures is analysed, and then the influence of the confining pressure scales, the angle, and the number of joints on the propagation law of the cylindrical blast wave in the jointed rock mass is studied. The experimental results show that the physical attenuation of the cylindrical wave in the intact rock mass decreases and then increases as the confining pressure increases from zero. Under zero confining pressure, the transmission coefficient of the cylindrical wave in the jointed rock mass decreases with the increase of joint angle, and the transmission coefficient increases with the increase of the joint angle under confining pressure. As the confining pressure increases from zero, the transmission coefficient shows a trend of increasing firstly and then decreasing.
Highlights
Within Earth’s crust, the underground rock mass is usually in a certain initial in situ stress environment
E reason for the above phenomenon is that the attenuation of the cylindrical stress wave in the jointed rock mass mainly consists of three parts: the physical attenuation resulting from propagation of stress wave in intact rocks, the attenuation resulting from interaction between stress waves and joints, and the geometrical attenuation resulting from the expansion of wave fronts
(2) e attenuation of the cylindrical stress wave in the jointed rock mass mainly consists of three parts: the physical attenuation resulting from the propagation of the stress wave in rocks, the geometrical attenuation resulting from the expansion of the stress wave fronts, and the attenuation resulting from the interaction between stress wave and joints. e geometric attenuation is only related to the geometry of the stress wave front, while the physical attenuation in rocks and the attenuation at the joints are affected by the initial stress
Summary
Within Earth’s crust, the underground rock mass is usually in a certain initial in situ stress environment. Earthquake engineering, underground engineering blasting excavation, and rock dynamics, it is of great significance in the research of the propagation and attenuation of blasting stress wave in in situ stressed rock mass. Us, the experimental study of the propagation law of two-dimensional stress wave (cylindrical wave) in jointed rock mass under initial stress is urgently needed. Erefore, a model test of cylindrical blasting stress wave propagation across the jointed rock mass under different initial stresses is carried out, and the influencing factors, such as the scale of the initial stress, the angle, and the number of joints, are discussed, respectively. Is study is helpful for better understanding stress wave propagation across in situ stressed rock mass and is of considerable importance to the design of the blasting excavation of rock mass in underground engineering The propagation of cylindrical stress wave in the intact rock mass under the same loading conditions is studied. is study is helpful for better understanding stress wave propagation across in situ stressed rock mass and is of considerable importance to the design of the blasting excavation of rock mass in underground engineering
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