Abstract The quality of back-fill grouting plays an essential role in the settlement control of shield tunneling, especially in the urban core area. Consequently, the tunneling professionals need practical ways to detect the grouting distribution behind the tunnel segment. Unfortunately, up to now, the traditional detection methods are not yet available for professional use. This paper presents a contribution to fill this gap, which is based on ground-penetrating radar(GPR). The bi-frequency back projection(BBP) algorithm is used to obtain a high-quality visualization of the grouting distribution. By employing an advanced segment-grouting-ground model using GPRmax 3.0, the correlation between two domain frequencies radar data is used to obtain the profile of the segment, the grouting, and the soil. Furthermore, the comparison of results of the BBP method with those obtained by the BP and CBP methods shows the high performance of the proposed method. Indeed, on the one hand, the diffraction and multiple reflections are reduced dramatically, and on the other hand, the anti-noise ability is significantly enhanced according to the Integrated Sidelobe Ratio(ISLR). The use of the proposed method in the construction of line 12 of the Shanghai metro allowed engineers to determine the location of rebars, the thickness of the grouting layer, and the grouting defects.

中文翻译：

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双频反投影探地雷达盾构隧道回填注浆质量评价

摘要 回填注浆质量对盾构隧道特别是城市核心区的沉降控制起着至关重要的作用。因此，隧道施工专业人员需要实用的方法来检测隧道段后面的注浆分布。遗憾的是，到目前为止，传统的检测方法还不能用于专业用途。本文提出了一种基于探地雷达 (GPR) 的贡献来填补这一空白。双频反投影（BBP）算法用于获得注浆分布的高质量可视化。通过使用使用 GPRmax 3.0 的先进的段-灌浆-地面模型，两个域频率雷达数据之间的相关性用于获得段、灌浆和土壤的剖面。此外，BBP 方法的结果与 BP 和 CBP 方法获得的结果的比较表明所提出的方法的高性能。事实上，一方面，衍射和多次反射显着减少，另一方面，根据综合旁瓣比（ISLR），抗噪能力显着增强。该方法在上海地铁12号线施工中的应用使工程师能够确定钢筋位置、灌浆层厚度和灌浆缺陷。根据综合旁瓣比（ISLR），抗噪能力显着增强。该方法在上海地铁12号线施工中的应用使工程师能够确定钢筋位置、灌浆层厚度和灌浆缺陷。根据综合旁瓣比（ISLR），抗噪能力显着增强。该方法在上海地铁12号线施工中的应用使工程师能够确定钢筋位置、灌浆层厚度和灌浆缺陷。