Wave attenuation in porous media and its protective effect on shock wave
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摘要: 孔隙介质对波的衰减极为显著,因此,它能有效降低介质中冲击波的能量。普遍来说,地球浅层介质均可视为孔隙介质,即可作为应对冲击波的天然防护材料,这对大型地下结构的安全防护有着重要的意义。本文通过对大振幅应力脉冲通过水或冰充填的人工节理孔隙介质的测量结果分析,讨论了节理中固相/液相水对爆炸效果的作用。基于双孔隙模型和部分饱和模型计算预测的P波速度以及岩石衰减和频散规律,与实测数据相一致。实验与模型预测均表明,节理中的水和冰对冲击波有较大的衰减,但是充水节理更为明显,且由于填充材料的不同会导致不同的介质性质。因此,在地球介质孔隙节理中充填不同衰减特性材料,可以满足不同情况下的冲击波防护需要。Abstract: The earth medium can be regarded as a porous medium. Because the attenuation of the wave is very significant, it can effectively reduce the energy of the shock wave. The porous medium can be used as a protective material for the shock wave, which is of special significance for large underground structures. In this paper, the measurement results of the artificial joint porous medium filled with water or ice with large amplitude and rapidly rising stress pulse are given. The influence of water as solid or liquid phase in the joint on the explosion effect is discussed. In this paper, two physical models of wave attenuation in porous media, namely double pore model and partial saturation model, are used. The calculation results show that the predicted P-wave velocity, as well as the degree of rock attenuation and dispersion, are consistent with the measured data. Water or ice in the joint has a great attenuation of shock wave. However, water filled joints are more obvious. Due to filling different materials, they show different properties. Therefore, pores and joints can be filled with different attenuation protective materials to meet the needs of different situations.
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Key words:
- pore medium /
- shock wave /
- double pore model /
- joint
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图 7 靶子/实验装置的几何示意图[4]。震动通过充填水或冰的岩石节理传播,应力计的箭头指向连接到应力计的电缆,通过跟踪电缆可进入靶子的固定装置
Figure 7. Target/impact geometries for experiments on shock propagation through rocks with water or ice-filled joints[4]. The arrows labeled “stress GAUGES” actually point to the cables connected to the stress gauges which are located at interfaces specified in the text as indicated by tracing the path of the cables into the target fixtures
表 1 5种不同孔隙度的孔隙材料在不同饱和度情况下对应力波振幅的影响
Table 1. Effect of five different porosity porous materials on stress wave amplitude under different saturation
材料 固体骨架密度$\,\rho$g/(g•cm−3) 干燥时的密度$\, \rho$dry/(g•cm−3) 总孔隙度
$ \phi $0 / %1 2.28 1.66 0.271 3 2.33 1.80 0.228 5 2.38 2.00 0.158 8 2.41 2.30 0.044 10 2.57 2.55 0.0064 -
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