A new optical method for soil stress and strain investigation

A new method for soil stress–strain investigations has been developed. In this method, a measuring system consisting of an SST (stress state transducer) and an optical system for soils has been used. Soil displacement and strain is to be determined with a novel, optical electronic system consisting of laser projectors, a shield and a video camera. Linear displacement of the SST in a deforming soil, rut depth as well as vertical and longitudinal deformations of the investigated soil can be determined. The main advantage of the new measuring system is the possibility of simultaneous measurement of both stress state components and deformations. Thus, an experimental soil stress–strain relationship can be determined. Detailed description of the instrumentation and methodology as well as some example results obtained in preliminary experiments have been presented. The laboratory and field experiments showed the performance of the system.