地震波斜入射结构面时,会产生2种不同类型的透射波,引起波场极性变化。采用弹簧模型描述非充填型结构面,运用弹簧模型讨论爆破地震波在结构面的传播特性。研究结果表明,爆破地震波在结构面处的波形转换系数以及P,SV波峰值比和偏振角的变化规律均能有效反映结构面刚度和入射角变化。结合现场试验方案,提出计算P,SV波峰值比和偏振角的方法,建立偏振角与入射角和结构面透射系数的关系;由现场试验数据得到空间各测点的P,SV波峰值比和偏振角的变化规律,进而确定结构面倾角。现场试验结果表明,根据各测点的P,SV波峰值比和偏振角变化规律可以准确确定结构面倾角。
Seismic waves are converted into two different types of transmission waves such as P wave and SV wave when seismic wave oblique incident goes through the rock mass interface.At the same time,wave field polarity is altered by rock mass interface.The non-filling interface is simplified as a spring model.Propagation characteristics of blasting seismic wave are analyzed by the spring model.The results show that interface stiffness and the variation of incidence angle can be effectively reflected by waveform transformation of seismic wave in interface and variation of the ratio of peak amplitude values between P wave and SV wave and variation of polarization angle.The ratio of peak values between P wave and SV wave and polarization angle can be calculated by analyzing the field test results.The relationship between polarization angle and incidence angle and transmission coefficient of interface is studied.Interface obliquity can be calculated by analyzing the ratio of peak amplitude values between P wave and SV wave and variation of polarization angle of different survey points that are obtained by field experiment.The field experiment and theoretical results indicate that interface obliquity can be determined by the ratio of peak values between P wave and SV wave and variation of polarization angle at different survey points.