Experimental study on vertical–lateral coupling pipe–soil interaction characteristics and speed amplification effect of marine pipelines

Abstract

ABSTRACT Under actual marine environment, the steel catenary pipeline’s touchdown zone frequently interacts with the seabed. The existing understanding of vertical–lateral coupling effect and speed amplification effect is insufficient at present. In this paper, the mechanism tests for the vertical and lateral soil resistance of small-scale pipes are carried out in both dry soil and saturated soil environments. The pipe–soil interaction presents quite different characteristics in dry soil and saturated soil due to the soil liquefaction effect. The pipe movement speed affects the soil reaction force significantly, especially in the high-speed range. During the vertical penetration of the pipe, soil shear strength follows a tri-linear relation. The lateral pipe–soil interaction could be classified into three phases i.e. fast growth, fast descent and stable fluctuation. The vertical–lateral coupling has a significant influence on pipe–soil interaction, presenting that the penetration depth greatly affects the lateral soil resistance.