On the undrained cyclic resistance of a partially saturated sand

The undrained cyclic resistance of sandy soils is a key factor in controlling earthquake-induced damage. It is well established that the degree of saturation significantly influences the undrained behaviour of sands, as a reduction in saturation decreases their liquefaction susceptibility. Induced partial saturation (IPS) or desaturation techniques have emerged as a promising alternative to enhance the undrained cyclic resistance of sands, offering also a viable liquefaction mitigation strategy. This study presents an experimental investigation into the undrained cyclic resistance of partially saturated sand through cyclic triaxial testing. Novel procedures are introduced to precisely monitor water content variations and assess the cyclic response across different degrees of saturation. The results confirm a substantial enhancement in undrained cyclic resistance as the degree of saturation decreases, reinforcing the effectiveness of IPS in mitigating liquefaction. These findings contribute valuable insights into the undrained cyclic behaviour of partially saturated sands to improve seismic resilience in geotechnical engineering.