Vibration measurements during soil-rock sounding – a comparison between accelerometers and geophones

Ehrmanntraut, E. and Wersäll, C. Vibration measurements during soil-rock sounding – a comparison between accelerometers and geophones. BNAM (Baltic-Nordic Acoustics Meeting) 2021.

Abstract: There are many different methods to retrieve information about ground properties prior to building and infrastructure projects. In Sweden the most common method is soil-rock sounding (Jb-sounding) which was developed in Norway in the 1990s. Soil-rock sounding is used for identifying the stratification of soil and the depth to bedrock and can be applied in different classes with different accuracy. It is an effective method with low costs but gives restricted information about the penetrated soft soil strata sequences and its properties. Improved knowledge about the presence of different soil and rock layers is necessary for a cost-effective design particularly of deep foundations. The purpose of this research project is to perform vibration measurements on the ground during soil-rock sounding to gain more knowledge about the penetrated ground. The measurements can be executed without influencing or affecting the sounding measurements and show that the frequency content of the signal is reflecting the properties of the penetrated soil layers. As an important step for developing the new measurement method vibration measurements with an accelerometer are compared to simultaneous measurements with a geophone in order to evaluate which sensor is most suitable for retrieving soil information. The results and recommendations of this analysis are presented in this paper.