Propagation Law And Numerical Simulation Of The Explosion Stress Wave In The Bedding Joint Rock Mass

When the national economy develops rapidly, engineering blasting is more and more widely used. The blasting technology plays more important role on the railway, mining, reservoirs and other large projects. Blasting has attracted more attention. The blasting technique and blasting safety monitoring technology have higher demand with the complex of blasting environment and expansion of blasting. After the blast of explosive in rock mass, the blasting shock wave is attenuation of blasting stress wave soon. There are a large number of the structures of natural rock mass, joint, crack, bedding and fault. These structures seriously influence on the propagation and attenuation of blasting stress wave. The propagation of stress wave in rock mass and the master of energy attenuation law have an important significance on our research on the surrounding rock structure dynamic stability. At present, the research on the dynamic characteristics of complete surrounding rock mass is large, while the research on structure mechanical properties of joint and fracture of surrounding rock is less. In fact, when the action of tectonic movement occurs, natural rock mass’ mechanical properties, vibration, permeability, the energy transfer and other performance can be changed due to its heterogeneous and anisotropic characteristics. This is the focus of many scholars attention.Taking a mine geological mechanics and basing on the principles of similarity theory, this paper established a complete and joint geological mechanical model, carried out the experimental study of the lower joint rock blasting load transmission law of stress wave and the numerical study of the complex layered joint propagation rules of blasting stress wave under the condition. This main content and conclusion is as follows:(1) Basing on Froude similarity principle, the geological mechanics model of the intact rock mass and joint rock had been designed and made, the blasting vibration test experiment was carried out. By analysis of the two model experiment of blasting vibration velocity time history curve, the stress wave spread of joint block can be received; there exists the anisotropic that the laws of propagation attenuation in the direction are different. For the blasting stress wave of the vertical or small Angle, the attenuation in the vertical and longitudinal direction is obvious and large amplitude, while the attenuation in the horizontal is not obvious. For the blasting stress wave of oblique incidence, the attenuation in horizontal and vertical direction is not obvious, the attenuation in longitudinal direction is obvious and larger amplitude.(2) The propagation of blasting stress wave and the charging structure have an important relationship by adopting the test experiment of different blasting parameters. The peak velocity of blasting stress wave depends on the loading intensity. When the cartridge distance is beyond a certain distance, the velocity temporal curve of actual measurement is the recent charge blasting stress wave, but it is not the total explosive stress wave produced by the overlay.(3) The numerical simulation method of the blasting stress wave propagation law in layered joint rock was established by the dynamic finite element method, and numerical simulation research of the blasting stress wave propagation law in layered joint rock was carried out, the numerical simulation results being agreed with the experimental results was gained.(4) By the numerical simulation research of the blasting stress wave propagation law in different spacing joint rock, the attenuation of the blasting stress wave increasing with the increase of joint spacing was gained. The changing trend of the corresponding points agrees with it in the intact joint rock. The distance between two points of different spacing model increases with the increase of joint spacing, which also can cause the attenuation of stress wave. Therefore, this paper put forward a new concept scale distance attenuation to describe the law of stress wave change with joint spacing, and gained the law of the scale distance attenuation presenting exponential attenuation with the increase of the joint spacing.(5) By studying on the numerical simulation of blasting stress wave propagation law in different dip Angle joint rock mass, when the joint Angle increases, the peak velocity of blasting stress wave increases, the transmission coefficient increases gradually, the reflection coefficient also increases gradually, and the attenuation coefficient reduces gradually. The functional relation of the stress wave attenuation and joint rock Angle changes was established.