Study on Calculation Method of VHMT Composite Bearing Capacity of Bucket Foundation for On-bottom Pipelines in Clay

Abstract

Bucket foundation normally used as the basis of the pipeline terminal in oilfield or wellhead manifold system, and the length-to-diameter ratio is usually between 1 and 2. In the stage of installation and operation of the pipeline, bucket foundation will sustain vertical and horizontal force, moment and torsional load from the upper structure. However, most existing equations of capacity envelopes for bucket foundations are in terms of length-to-diameter ratios less than 1, and the influence of torsional load on composite bearing capacity of bucket foundation is not considered. In this study, finite element simulations are conducted to study the interaction between soil and bucket foundation (with a length-to-diameter ratio between 1 and 2) subjected to combined loadings. The influence of torsion on uniaxial bearing capacity and VHM composite bearing capacity is discussed respectively. The results showed that the torsion can cause bucket foundation VHM of bearing capacity of composite envelope surface decrease. With regression analysis of the calculation results, calculation formula of composite bearing capacity considering the effects of torsion is summarized.