This is the third paper of three which discuss the seismic performance of a jack-up rig operating at several sites for the Tangguh development, offshore Papua Barat, Indonesia. The companion paper, Galanes-Alvarez et al. (2020) presents general details on the project while the current paper and Erbrich et al. (2020) concentrate on presenting key technical details associated with various aspects of the state-of-the-art seismic modelling that was conducted to assess the installation and in-place seismic performance of a jack-up rig operating at several sites for the Tangguh development. More specifically, the current paper discusses how differences in soil drainage conditions between the initial penetration process and during a seismic event were addressed, which was important in sandy layers (where present). A procedure is also described that was used to assess the degree of soil softening where cyclic induced excess pore pressure accumulation in sand layers was a consideration. How this was included in the seismic analysis is also presented.
Carl Erbrich, Kok Kuen Lee, Sidney Lam, Kee Kiat Tho, Hugo Galanes-Alvarez and Armedito Ramadhan
Keywords: Jack-up, seismic, finite element analysis, pore pressure accumulation
Publisher: DFI