An optical technique for investigating soil displacement patterns

An optical, nonintrusive technique for measuring soil deformation in three- dimensional laboratory scale tests is described. The technique combines the use of a video camera capable of recording the movement of targets to a hi gh resolution, and a transparent porous material possessing geotechnical pr operties similar to natural clay. The technique is demonstrated in a model test conducted to measure soil deformation patterns around penetrometers. T he displacement measurements compare well with results from other published tests and indicate that the technique can provide better resolution than h as been previously achieved in similar laboratory tests.