基于F-K和Kirchhoff法的隧道衬砌双层钢筋偏移成像研究

Research on Migration Imaging of Double-layer Reinforcement in Tunnel Lining Based on F-K and Kirchhoff Methods

针对隧道衬砌结构钢筋数量缺失与布置间距不合理等质量问题,基于探地雷达正演模拟试验,对隧道衬砌双层正对钢筋进行探测研究,分别采用F-K法和Kirchhoff法对钢筋检测图像进行偏移归位处理,探究钢筋回波信号偏移归位效果,比较两种偏移方法的优劣。结果表明:理想无噪声条件下,F-K法和Kirchhoff法能获取相同的偏移速度,并使衬砌双层钢筋回波信号准确归位,但由F-K偏移法得到的偏移图像信息熵更小,偏移效果更精确。含噪声情况下,F-K偏移法具有更强的抗噪性,能获取稳定有效的偏移速度,偏移处理后钢筋信号能量集中且易于识别。

In response to quality issues such as missing quantity and unreasonable spacing of reinforcements in the tunnel lining structure,based on the forward modeling test of Ground Penetrating Radar,the detection of double-layer facing reinforcement in the tunnel lining is studied.The F-K method and Kirchhoff method are used to migrate and return the reinforcement detection images,and the effect of reinforcement echo signal migration and return is explored.The advantages and disadvantages of the two migration methods are compared.The results show that the F-K method and Kirchhoff method can obtain the same migration speed and accurately locate the echo signal of the double-layer reinforcement in the lining under the ideal noiseless conditions.However,the information entropy of the migration image obtained by the F-K migration method is smaller,and the migration effect is more accurate.In the presence of noise,the F-K migration method has stronger noise resistance and can obtain stable and effective migration speed.After migration processing,the reinforcement signal energy is concentrated and easy to identify.