Investigation of sinkholes on the roads by GPR: Application to HCM city, Vietnam

HCM city is the largest city in Vietnam with about 3,000 km of transport roads for 8 min people. There were many sinkholes appeared on the roads during the period of 2009-2010 years of different diameter. The location of those sinkholes is required to be done to forecast safety transportation in future for. We proposed to use GPR technique for location of these sinkholes in the city by Ramac X3M with 500 MHz frequency equipment and other for deeper target for instance Pulse Ekko100A with 200 and 100 MHz frequency antennas. The majority of anomalies was found by GPR measurements related with subsurface holes or soft-material by 0.5-2 m of diameter and 0.5-4 m of depth. In this paper, we present result of processing and interpreting GPR data for 3-D image for location of 3 sinkholes on the road in the city by using network of 16 × 17 GPR lines measurement. To obtain accurate parameters of GPR anomaly by data processing, we used CMP configuration for estimation of the velocity in-site. The GPR images reveal the distribution of the sinkholes and other weakness zone by comparing with dug holes.