GPR Technology: Detecting Collapse Hazards Before They Strike in Urban Construction

In recent years, urban construction has developed rapidly, but it is accompanied by frequent underground disaster accidents, among which the hazards of road collapse deserve attention. Road collapse not only causes traffic paralysis, but also damages infrastructure such as communication, water supply, gas transmission and power, resulting in significant loss of life and property and adverse social impacts.

Data shows that underground disasters frequently occur in areas with dense pipelines and concentrated dark channels, especially in drainage pipeline areas. The drainage pipelines under urban roads have long been subjected to heavy road traffic loads. Once aging or leakage occurs, the soil and water around the drainage pipelines will be locally lost, causing concentrated seepage of surface water, which further aggravates soil erosion and forms underground cavities over time. In addition, some special geological conditions, such as karst and stratum subsidence, as well as the adverse effects of nearby construction, are also important factors causing collapse. Studies have shown that the burial depth of underground cavities is related to the collapse risk. When the burial depth is shallow, the cavities are more affected by the cyclic load of vehicles and more prone to collapse. Moreover, the lateral expansion and height increase of cavities will both increase the risk of road subsidence and reduce the stability of roadbeds.

To address the hidden dangers posed by underground cavities, Ground Penetrating Radar (GPR) has become an effective tool for preventing road collapse. It uses the principle that high-frequency electromagnetic waves generate reflections when encountering interfaces with electrical property differences during their propagation in underground media. By receiving reflected wave signals and analyzing information such as the two-way travel time, amplitude and phase of electromagnetic waves, it can infer the structure of underground media. For underground cavities, due to their obvious electrical property differences from the surrounding soil, GPR can accurately capture the abnormal changes of reflected waves, so as to determine the key information such as the location, size and burial depth of cavities.

Compared with traditional detection methods, Ground Penetrating Radar features non-invasiveness, fast detection speed and high resolution. It can quickly and efficiently detect large areas without damaging the road surface, accurately locate hidden dangers of underground cavities, provide scientific basis for urban road maintenance, pipeline network repair and other work, prevent road collapse accidents from the source, and ensure the safe operation of cities.