Characterization of Model Uncertainty for the Vertical Pullout Capacity of Helical Anchors in Cohesive Soils

• Main Authors: Po Cheng, Jiang Tao Yi, Fei Liu, Jun Jie Dong
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: Journal of Marine Science and Engineering
• Subjects: helical anchor; the coupled Eulerian–Lagrangian analysis; model uncertainty; pullout capacity; cylindrical shear method
• Online Access: https://www.mdpi.com/2077-1312/8/10/738

This paper conducts coupled Eulerian–Lagrangian (<i>CEL</i>) analysis to characterize the model uncertainty of using the cylindrical shear method (<i>CSM</i>) to predict the pullout capacity of helical anchors in cohesive soils. The model factor <i>M</i> is adopted to represent the model uncertainty, which is equal to the value of measured capacity divided by estimated solution. The model factor <i>M_cel</i> can be considered to be a random variable with a lognormal distribution, and its mean value and coefficient of variation (<i>COV</i>) are 1.02 and 0.1, respectively. Correction factor <i>η</i> is introduced when comparing <i>CSM</i> and <i>CEL</i>, which is found to be influenced by input parameters. The dependence on input parameters is removed by performing regression analysis and the regression equation <i>f</i> is obtained. Substituting the regression equation <i>f</i> into the original <i>CSM</i> constitutes the modified <i>CSM</i> (<i>MCSM</i>), and the model factor of <i>MCSM</i> can be modeled as a random variable with a lognormal distribution, and its mean value and <i>COV</i> are 1.02 and 0.13, respectively. Finally, 13 filed tests are collected to compare the prediction accuracy, the results show that the prediction error range of <i>MCSM</i> is mostly within 15%. The present findings might be helpful for engineers and designers to estimate the pullout capacity of helical anchors in cohesive soils more confidently.