SHEAR WAVE VELOCITIES FOR SAMPLE QUALITY ASSESSMENT ON A RESIDUAL SOIL

For the assessment of the quality of laboratory samples, a number of methods are available, though not universally applicable to any soils. This paper examines the issue of sampling quality and its assessment using comparisons between shear wave velocity measurements in situ and in recovered samples as the base, which is very useful in naturally structured granular soils, like residual soils. For this purpose, cross-hole and down-hole tests were performed in the field and bender elements measurements were made on triaxial samples collected from two experimental sites on residual soil from Porto granite. Various sampling techniques and tools were used, including block sampling and different tube samplers. The analysis of the results has led to a new classification of sampling quality and sample condition based on the comparison of normalised shear wave velocities in the field and in the laboratory.