探地雷达（groundpenetrating radar，GPR）在工程检测领域应用广泛，特别是应用于隧道衬砌结构检测。利用时域有限差分方法（finite difference time domain，FDTD）和完全匹配层（perfect match layer，PML）吸收边界条件，采用900 MHz天线，模拟了不同间距、不同深度、不同对应位置的单、双层钢筋混凝土结构，并运用频率-波速域（F-K）波动方程偏移技术分别进行了成像处理。研究表明： 1）有效探测范围内钢筋间距、埋深越大时，干扰信号越少，钢筋的反映越明显； 2）F-K偏移可较好地分辨出单层（上层）钢筋，斜对双层钢筋的分辨率比正对高。

Groundpenetrating Radar(GPR) is widely applied in engineering test, especially for tunnel lining structure. Based on Finite Difference Time Domain (FDTD) and Perfect Match Layer (PML) absorbing boundary condition, 900 MHz antenna is used to simulate singlelayer and doublelayer reinforced concrete with different spacing, depth and corresponding position. FK migration is used for image processing. The research shows: (1) within the range of effective detection, if the rebar spacing is larger and the depth is deeper, the interference signal is less and the response of the rebar is more obvious; (2) FK migration can identify singlelayer (or upperlayer) rebar, in the process of 2layer reinforcement simulation and migration, the effect of oblique is better than opposite.