Confining pressure-dependency of bulk modulus of sand during liquefaction

In the elasto-plastic constitutive model, bulk modulus is one of the most important parameters to control the change of effective stress under undrained condition. However, the experimental research on bulk modulus of sand during liquefaction has not been conducted so far. In this paper, therefore, the bulk modulus of Toyoura sand was measured directly during liquefaction using a hollow cylindrical torsional shear testing device equipped with a volumetric strain control device. This study found that the bulk modulus corrected by membrane penetration effect during liquefaction process is constant under relatively high confining pressure, and that the stress dependency of bulk modulus during liquefaction process is different from that during swelling process.