Monitoring Surcharge Loading-Induced Densification of Soft Soils through Time-Domain Reflectometry

Engineers often face the challenge of constructing on soft soils that are associated with low bearing capacity and severe post-constructional settlements. In the subsurface zone, volume-change behavior of saturated soft soil is important in predicting the potential settlements. In this study, laboratory experiments have been conducted to monitor densification and consolidation processes of two soft geomaterials under incremental surcharge loading. During these experiments, densification of the geomaterials have been evaluated through a noninvasive scheme using electromagnetic (EM) methods. For this purpose, a time-domain reflectometry (TDR)-based approach has been accomplished by means of rod probe sensors. Changes of TDR waveforms under several surcharge loadings have been analyzed to establish soil properties, such as dielectric permittivity, volumetric water content, density, and porosity. Translating this laboratory-based nondestructive monitoring scheme to the field would potentially facilitate in management of ground improvement trials prior to, during, and after construction on soft soil deposits.