Detection of cracks in cemented loess of ancient buildings using remote sensing

Abstract

The bases of ancient Chinese buildings are prone to deformation, cracks, and other hidden problems due to their age and other reasons. Rainfall and water seepage produce great harm to the cracks of soil plinths. Based on a ground-penetrating radar method, detecting cracks and water erosion defects is important for protecting ancient buildings. This study examines the reflection characteristics of ground-penetrating radar (GPR) waves at different lithological interfaces. Physical experiments and their numerical and physical laws were used to study the reflection characteristics of GPR incidents from brick to air, unsaturated soil, water, and metal interfaces. The model was applied to detect defects of the Xi’an Bell Tower and the main research results are as follows. The echo amplitude of GPR was positively correlated with the relative permittivity of the bedding layer, and its basic law conforms to the positive logarithmic curve. The hyperbolic opening of water erosion imaging of the base-compacted soil is larger, the attenuation effect increases and the signal reflection is obvious. These results provide the theoretical basis and technical support for the actual detection of water erosion deterioration of loess in similar projects, and this provides theoretical and technical references for rapid identification and management of defects in ancient buildings.