Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Introduction. In Poland, the number of forest roads with paved and unpaved surfaces is increasing. All ways by the Building Law must be reviewed and approved for road traffic. Moreover, the condition and quality monitoring of these roads. Many researchers are looking for new solutions that improve work and give better results. Such a proposal may be a method that uses a Ground Penetrating Radar (GPR). GPR is non-destructive testing method. GPR technique is used in many applications, for example, thickness measurement of public road surfaces. The data obtained by the ground penetrating radar allows creating a longitudinal profile of the entire studied section. We receive information about the structure of the road, layer thickness, anomalies (e.g. soil subsidence, interruption of the layered continuity, cracks). This data provides information on a correctly conducted road investment. Monitoring the condition and quality of roads can significantly affect savings during repairs. The aim is to study the usefulness of GPR in estimating the thickness of construction layers of a forest road.

Material and methods. The research was conducted on sections of the experimental ways. This road was built in the Gryfino Forest District (NW Part of Poland, South of Szczecin). Data acquisition using GPR made it possible to create radargrams. An antenna with a central frequency of 750 MHz (MALA Ground Explorer (GX) HDR) was used for fieldwork. Longitudinal profiles with a length of 25 meters were made. These profiles are part of test sections with improved and unimproved hard surfaces. The obtained records were post-processed in the MALÅ Object Mapper and RAMAC Ground Vision software, where they were further processed.

Results and conclusions. Based on the measurements and obtained radargrams, it was observed that the ground penetrating radar with an antenna (central frequency of 750 MHz), can be used successfully during inspection works for forest roads, too. The data processing confirms the possibility of continuous monitoring of the road (longitudinal profiles), observing the structure of the road, the thickness of the construction layers and the occurring anomalies.