中文摘要：

利用地质雷达对冻结工程进行无损检测中，冻土中电磁波速的确定是影响冻结壁探测精度至关重要的参数，而电磁波速主要由介质的介电常数所决定的。为此，本文采用矢量网络分析仪，实测不同含水量条件下-30℃—25℃上海长江隧道联络道灰色粉质黏土在0．1～1GHz频率段的介电常数，并建立上海灰色粉质黏土介电常数的频散经验公式。研究表明，冻结前后上海灰色粉质黏土的介电常数有显著变化；温度变化对冻结状态介电常数影响较大，对融化状态下的介电常数影响不大。为今后地质雷达用于上海地区冻结工程的探测提供重要的依据，对冻土温度场的定量反演也有重要价值。

英文摘要：

Vector network analyzer was employed to measure the dielectric constant of Shanghai grey silty clay in the 0.1 - 1GHz frequency band, under different water contents and temperatures -30℃- 25℃. The dispersion equation for the dielectric constant is established. The study shows that its dielectric constant significantly varies in pre and post freezing conditions. Post freezing change of the temperature has a greater impact on dielectric constant, while the impact is small in pre freezing. The results of this study may be applied to Ground Penetrating Radar （GPR） exploration of ground freezing and to the inversion of the frozen soil temperature field in Shanghai area.