Tilt Table Test for Interface Shear Resistance Between Flowlines and Soils

Abstract

This paper describes a tilt table test method for measuring the shear resistance between flowlines and supporting soils. This shear resistance is important in considering buckling and walking in the design of flowlines. A significant challenge in measuring the shear resistance is the very low effective normal stresses that exist at the interface in field conditions. Since the measured stresses will be small, even small amounts of friction in a test device can adversely affect the results. The tilt table method overcomes this problem by using gravity to apply the normal and shear stresses to the soil-flowline interface, eliminating the need for a mechanical loading system. A set of test results is presented to demonstrate how the test method can be used to measure the resistance between the flowline and the soil. These results illustrate that the type of flowline coating and the effective normal stress affect the shear resistance.