基于双平方根算子叠前深度偏移成像技术的结构损伤成像与探测  

Structural damage imaging and detection based on prestack depth migration imaging technology of double square root operator

作　　者：郭原草[1] 郭少华[1] 

机构地区：[1]中南大学土木工程学院,湖南长沙410004

出　　处：《中南大学学报（自然科学版）》2013年第5期2022-2030,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(50778179)

摘　　要：介绍一种基于双平方根算子的叠前深度偏移方法用于结构损伤探测。首先推导上行波传播时间(走时)的全微分表达式,推导在频率波数域和频率空间域中,用源点和接收点坐标表示的双平方根算子波动方程。然后,用频率空间域的有限差分法及混合法进行双平方根算子的波场外推,推导关于炮点和检波点的差分方程,以及双平方根算子混合法波场外推公式。最后,用Marmousi数据体对结构损伤进行偏移成像。根据双程波动方程分析该方法的数值频散性、奇异性以及波场、位移、振幅、能量、动应力集中系数等力学特征,计算得到波场快照图和剖面图,达到对结构损伤成像的目的。数值算例证明了这种方法的适用性。A prestack depth migration based on the double square root operator was introduced. Firstly, the total difference expression of wave propagation time was deduced, then, the double square root operator wave equation expressed by the source and receiver coordinate was deduced in two spaces, respectively. Then, the double square root operator wave field extrapolation was executed by the finite difference and mixed method. The finite difference equations about the explosion and receiver were deduced. At last, the migration image was executed based on the Marmousi data.The numerical volatilization, singularity, wave field, displacement, amplitude, energy, dynamic stress concentration coefficiency according to the double distance wave equation, the wave field snapshot and section were ultimately obtained. Numerical examples testify the feasibility of the method.

关 键 词：叠前深度偏移 结构损伤成像 双平方根算子 波场外推 

分 类 号：TG111.3[金属学及工艺—物理冶金]