Some Design Guidelines for Suction Pile Installation under Self-weight and Suction in Caspian Sea

摘要

In the past, most of the Iranian offshore oil production activities werernconcentrated in Persian Gulf area in which the water depths rangernbetween 40 to 80 m. Some studies have lately started in Caspian Searnin northern Iran, at water depths ranging between 700 to 1100 m. Thernordinary steel driven piles with jackets are no longer applicable inrnsuch water depths, and TLP type structures connected to sea bottomrnby means of suction pile are one major alternative under suchrnconditions. The main objective of this paper is to present the details ofrna FEM modeling of suction pile installation under its own weight asrnwell as suction in Caspian Sea bed.rnAn elaborate geotechnical study at around 700 to 1100 m water depthrnzones was conducted lately to obtain the seabed soil conditions. Thernangle of friction between pile and surrounding soil and soil strengthrnparameters were determined through back analysis from a suction pilerntype soil sampler equipped with a fuse type tensile element. The soilrnlayer mostly consists of soft clay with 10 to 12 percent of sand, hencernthe permeability is low. PLAXIS V. 7.2 was used to simulate therninstallation procedure in fine-grained soils. The model verificationrnwas on the basis of laboratory test data available in literature. Arnsimplified design method is proposed for suction pressurerndetermination of different pile sizes for Caspian Sea soil conditions.