Geophysical investigation of road failure the case of the main street of Alue Naga, Banda Aceh, Indonesia

Abstract

A geophysical investigation has been conducted on the road to assess the subsurface soil characteristics. The study investigates the causes of road failure around the body of the damaged roads in the main street of Alue Naga, Syiah Kuala, Banda Aceh to determine the variations of rocks charge ability and resistivity value of the subsurface of the study area. The method employed for this study was 2D Electrical Resistivity and Induced Polarization (IP) method with using Wenner-Schlumberger array. Two profiles covering a distance of 100 meters each were established parallel to the road pavement along the stable and unstable sections of the road. Data were collected along the two profiles using ABEM Terra meter SAS 4000. The observed field data were processed and inverted using 2-D modelling inversion algorithm (RES2DINV Software). The result shows the presence of low resistivity and charge ability value at several parts of both line 1 and line 2. Both lines observed the 0-1.73 msec of charge ability value and <1 ohm.m of resistivity value; those values were interpreted as alluvium. In conclusion, the low resistivity and charge ability value present that the area investigation was a layer of permeable, especially in the central part which was cohesive, and led to the instability and weakness of the load-carrying capacity.