Effect of interface conditions on mudmat bearing capacity under V–H–M loading

Sliding mudmat foundations, also termed as tolerably mobile foundations, are allowed to slide on the seabed, such that the overstress on the connected pipeline due to high temperature and high pressure can be significantly reduced. Unlike traditional mudmat foundations, with the horizontal displacement confined, horizontal movement of the sliding mudmat is achieved by reducing the friction along the mudmat–soil interface. This study aims at investigating the effect of the interface friction ratio on the response of the mudmat under uniaxial or combined V–H–M loading by conducting a series of finite-element analyses. Based on the numerical results, empirical expressions are proposed to quantitatively characterise the uniaxial capacity of the mudmat by considering varied soil heterogeneity coefficients and interface friction ratios. Moreover, failure envelopes of the mudmat are established to assess the capacity of the mudmat under combined V–H–M loading.