Strength reduction for upheaval buckling of buried pipes in blocky clay backfill

OCEAN ENGINEERING

卷:130

Article

Brennan, Andrew John¹  Ghahremani, Mahmoud¹  Brown, Michael John¹ 

[1] Univ Dundee, Sch Sci & Engn, Dundee DD1 4HN, Scotland

关键词: Pipeline geotechnics;    Upheaval buckling;    Centrifuge modeling;    Clay;   

DOI  :  10.1016/j.oceaneng.2016.12.006

来源: Elsevier

【 摘 要 】

Offshore pipelines are often buried to protect the pipeline from external loads and upheaval buckling. Models for pipe uplift resistance in clay soils are based predominantly on homogenous backfill conditions. In practice, however, there will be significant soil disturbance during installation. With certain trenching techniques this may produce a backfill more akin to a matrix of lumps of intact soil connected by weaker remoulded interfaces. This research uses centrifuge modeling to assess the resistance provided by a representative lumpy clay backfill that has experienced self-weight consolidation. A model pipe is then uplifted through this model backfill in order to assess the soil uplift resistance. Results show that the uplift resistance in this material is governed strongly by the size of the lumps and, to a lesser extent, by the rate at which displacement occurs. When interpreted in terms of the strength reduction eta, that may be used to correct between theoretical and measured uplifts, lower values were derived than those currently used based on intact soils. The value of eta is seen to be controlled by a non-dimensional drainage parameter, but may be practically estimated based on an estimate of the size of lumps relative to the pipe diameter.

【 授权许可】

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