Numerical investigation of flow liquefaction in Nerlerk underwater berm is done considering field data. The flow failure criterion proposed by Najma and Latifi is used to determine flow initiation and spreading via the Berm structure. This is done using Abaqus user material subroutine (UMAT) for coding Dafalias-Manzari constitutive model. The undrained triaxial tests are used for the calibration and verification of constitutive model coding. Application and performance of flow failure criterion are checked for these models. Then, Nerlerk underwater berm is numerically modeled considering calibration of constitutive model parameters from field investigation data. The performance of the stress ratio criterion is compared to the liquefaction determination method based on plastic modulus. Analyzing flow failure in a 3D numerical model of a real case is done for the first time, adding a constitutive model to commercial software in conjunction with two different flow detection equations defined as solution-dependent variables in developed user material code. This study reveals the ability of developed code in numerical modelling of flow failure initiation and expansion in a real case numerical model, which is the main target of this study.