Centrifuge modelling of pipe-soil interaction in clay with crust layer

Influence of stress history on undrained cyclic shear strength evolution

“…The RSL represents a state towards which soil strength fully degrades under large strains with negligible pore pressure dissipation (and therefore negligible strength recovery). A similar approach was employed by Hou et al (2021) who utilised these concepts to describe measured changes in soil-pipe stiffness during centrifuge tests of a model riser segment. This is equivalent to the traditionally defined critical state line (Schofield and Wroth 1968).…”

“…To locate the ISL in -space, Hou et al (2021) assumed that the mean effective stress on 𝑒 𝜎 ′ 𝑣 the K o NCL is double the value on the CSL at the same void ratio (as adopted in the Modified Cam Clay (MCC) model for isotropically consolidated soils) and that the position of the RSL is defined by the soil sensitivity with respect to the ISL. They postulated that soil states in Zone A (between the K o NCL and ISL) and Zone C (left of the RSL) will respectively harden or soften after a period of cyclic remoulding, whereas soil states in Zone B (between the ISL and RSL) will harden, but to a lesser degree than soils in Zone A (see Figure 2…”

“…In this paper, this knowledge gap will be filled by analysing the results from a series of long-term cyclic T-bar tests. Also, the assumption made by Hou et al (2021) (3…”

“…Therefore, the strength on the RSL can also be defined by equation (A1), by replacing with . Hence, as in Hou et al (2021) (albeit for one-𝑝 ′ 𝐼𝑆𝐿 𝑝 ′ 𝑅𝑆𝐿 dimensional stress conditions), the soil sensitivity ( ) is defined as:…”

“…Insights into the effects of soil stress history (quantified using the overconsolidation ratio -OCR -given as the ratio of maximum previous vertical effective stress to current vertical effective stress) on capacity changes for offshore infrastructure under cyclic loading can be obtained from a recent study by Hou et al (2021). They reported centrifuge tests investigating…”