Study on changing the dielectric constant and radar reflection of foamed polyurethane by adding graphite

Abstract

Polyurethane is often used for filling and plugging in engineering. However, it is difficult to detect the restoration effect by GPR. For the convenience of detection, graphite was added into polyurethane to change its dielectric constant. Five ratios were designed to measure the dielectric constant under dry and wet conditions. The dielectric constant of polyurethane under dry and wet conditions and the relationship between graphite dosage and detection frequency were obtained. The reflection coefficient of polyurethane-Air interface to electromagnetic wave is calculated. The reflection coefficient is increased due to the addition of graphite. According to the results of GPR forward modeling, the filling body can be imaged, and the filling effect can be distinguished obviously.