Investigating the changes in the geophysical and geotechnical properties of fine-grained soils when exposed to changes in vertically applied loads

[摘要] Fine-grained soils, containing clay minerals, are known to experience potentially considerable changes in geotechnical properties when exposed to external loads. These could lead to loss of mechanical performance or catastrophic failure. Therefore, this research focuses on simple geophysical sensing techniques which could contribute to a warning system based on correlations between geotechnical and geophysical parameters.Fine-grained soils of differing plasticity were exposed to changes in vertical loading in bespoke experimental chambers. The geophysical properties investigated were apparent permittivity (AP) and bulk electric conductivity (BEC) in a kHz frequency range, measured with time domain reflectometry (TDR) and bulk electrical conductivity (EC) in a Hz frequency range, measured with electrical resistivity (ER).For what is believed to be the first time, TDR measurements were carried out continuously and in both the vertical and horizontal direction during the volumetric change of the soil, induced by changes in the loading conditions. In parallel, EC was measured, utilising the bespoke test chambers and custom-built acquisition system.Based on the results, it is envisaged that monitoring the relative change in AP and BEC over time, in conjunction with spatially distributed ER arrays, could provide temporal indication of the soil response to load under near-saturated conditions.

[发布机构] University:University of Birmingham;Department:School of Engineering, Department of Civil Engineering

[关键词] T Technology;TA Engineering (General). Civil engineering (General)