

For soft soils, sampling methods, specimen preparation and subsequent test results are all affected by the degree of soil structure and level of destructuration occurring during these phases. Consolidation has been shown to be a primary means for restoring a soft soil's structure, or an approximation of that structure. The amount of this restoration can be quantified by comparing the measured shear wave velocity values before and after various test phases. Shear waves can be generated and received by bender elements that are composed of piezoceramic plates. When bender elements are inserted into a triaxial testing system, they provide non-destructive testing during an ongoing triaxial test. In this research, bender elements are implemented in an automated triaxial apparatus using methods developed by Landon (2004). Two different soil types, one sampled using conventional tube sampling and one using Sherbrooke-type block sampling, were tested to assess how reconsolidation affects the structure of the soil, by comparing bender element data. A MatLab® based program was used to actuate the excitation of benders, and to measure and analyze the resulting shear wave transmission. By comparing shear wave velocity results at various stages of the test, the change in the soil structure as a result of those test stages can be inferred. The results show that, based on bender element shear wave velocity measurements, the back pressure and consolidation phases help to restore the shear wave velocity values and the shearing phase only marginally degrades the structure, even at relatively high, end-of-shear strains.