The motion of debris flows is controlled by the interaction of their fluid and solid components. In this work, a general two-phase model framework (Pudasaini, 2012) is adopted which captures the coupled effects of the individual phase dynamics to the overall mobility. While solving the model equations, the fluid phase is treated as a viscous Newtonian liquid while the solid phase is considered to be a granular material obeying a recently developed visco-inertial constitutive rheology. Solid and fluid components in the mixture are coupled through the interaction forces, namely buoyancy, drag, and virtual mass. The model is calibrated against results from instrumented flume experiments and from field measurements of saturated, channelized debris flows. The numerical model captures the enhanced mobility of debris flows due to the presence of interstitial fluid and provides better predictions of the flow dynamics relative to those obtained from single-phase frameworks. Better modeling agreement is obtained for granular-fluid flows with relatively high fluid content. The model is then used to simulate real debris flow events, including a case that occurred in the proximity of the Sichuan-Tibet Railway, where good agreement with reported field measurements is obtained. This modeling framework is expected to improve mitigation strategies for debris flows hazards.