Yue Yan

Bio: Yue Yan is an academic researcher from Tianjin University. The author has contributed to research in topics: Bearing capacity & Caisson. The author has an hindex of 2, co-authored 3 publications receiving 18 citations.

Effects of tension gap on the holding capacity of suction anchors

Abstract: Suction anchors are popular anchoring solutions for station-keeping of offshore floating facilities. For the in-place holding capacity design of these anchors, there is a debate in practice regarding the possibility of developing a tension gap on the rear side of the anchor and how to account for it in design. This study is carried out to shed further light on this debate. Analytical and finite element analyses are reported in this study which investigate: i) the optimal padeye depths and the influencing factors, for both free gapping and no gapping interface conditions; ii) the effect of tension gap on the anchor's holding capacity when the padeye is placed at optimal depths; iii) the effect of tension gap on the anchor's holding capacity when the padeye is placed at non-optimal depths. Strategy to account for tension gap in practical design is provided.

Bearing capacity of a side-rounded suction caisson foundation under general loading in clay

Abstract: A novel side-rounded suction caisson foundation is proposed in this study. Compared to a conventional circular shape in plan, it has a rectangular middle section inserted in between the two circular halves for increased moment capacity. This paper presents an investigation into the bearing performance of this novel foundation in clay under uniaxial and combined loading by means of an extensive finite element parametric analysis. It is found that by adopting a dimensionless equivalent embedment ratio and a dimensionless equivalent strength heterogeneity ratio, which account for the side-rounded shape of the proposed foundation, its design approach can be unified with an existing framework established for conventional skirted circular footings. The advantage of the proposed foundation and the application of the proposed design method is demonstrated through an example application.

Interpretation of the Torsional Resistance of Shallowly Embedded Hemiball Penetrometer

Abstract: The hemiball penetrometer is a geotechnical device developed to measure the property of surficial seabed sediments (<0.5 m), which is of most significance for pipeline design and for situa...

P-ultimate for undrained analysis of laterally loaded piles. discussion and closure

Abstract: A discussion of a paper with the aforementioned title by Murff and Hamilton, published in this journal (Volume 119, Number 1, January 1993), is presented The discussion focuses on laterally loaded piles in layered soils Maugeri, Castelli, and Motta assert that the authors' method overpredicts the ultimate lateral resistance on the pile Discussion is followed by closure from the authors

Parametric study of hybrid monopile foundation for offshore wind turbines in cohesionless soil

Abstract: The hybrid monopile foundation is an alternative for offshore wind turbines. The parametric study has been performed through a series of centrifuge tests for the optimal design of the hybrid foundation. The wheel diameter, wheel thickness, and pile length are considered in the analysis. The lateral capacity of the hybrid monopile foundation increases with the wheel diameter and tends to accelerate; it increases linearly with the wheel thickness and pile length. The influence of the wheel diameter is more pronounced compared to the other parameters. The hybrid monopile demonstrates an enhanced performance compared to the monopile and the single-wheel. The improvement is more significant at small pile lengths. The hybrid monopile shows its advantages in reducing the pile length. It has great potential in reducing capital costs. An analytical method is proposed by scaling the individual capacity of the pile and the wheel. A design chart for the scale factor is suggested. The calculation is applicable for determining the initial dimension of the hybrid monopile foundation, and the ultimate lateral capacity is assessed.

Load bearing behaviors of composite bucket foundations for offshore wind turbines on layered soil under combined loading

Abstract: This paper focuses on the load bearing behaviors of the composite bucket foundation (CBF) which has been proposed and applied to offshore wind turbines in China. With the numerical analysis method, the soil-structure interaction and the practical project-based dimensional and property parameters are described. The load bearing behaviors of the CBF are investigated in terms of deformations (structure and soil), load bearing ratios, and geometric effects. Under the consideration of multi soil profiles and combined loading condition, the load bearing behaviors of the CBF can be concluded. Soil property can change the load bearing ratio especially when the compartment plates are involved. The lid-bearing mode is dominant for CBF when the upper layer of the soil is high in strength. Without the compartment plates, the bucket wall contributes more than the lid. The load bearing behavior is influenced by the bucket diameter, soil strength and the compartment plates. The results are of reference value to understand the load bearing behaviors and serve as a basis for optimizing the structure design for cost-reduction.

Site-specific soil reaction model for monopiles in soft clay based on laboratory element stress-strain curves

Abstract: Large-diameter monopiles are the predominant foundation solution for supporting offshore wind turbines. They are conventionally designed using soil reaction curves developed for long slender piles used for supporting offshore oil and gas platforms (e.g., the API p-y model). However, due to the difference in the length/diameter ratio and the resulting soil mechanisms, the use of p-y curves alone can lead to significant under-prediction of the lateral stiffness and capacity of monopiles. To overcome the shortcoming, the authors have previously proposed a conceptual two-spring framework, i.e., the so-called ‘p-y + MR-θR’ model, to capture the monopile response in soft clay under lateral loading. The framework uses distributed p-y springs to consider the lateral soil resistance along the pile above the rotation point (RP) and a single moment-rotation (MR-θR) spring attached at the RP to capture the entire soil resistance below the RP, i.e., the distributed resistance along the pile, base shear and base moment at the pile tip. The proposed p-y and MR-θR springs were curve-fitted to the results of 3D numerical analyses. However, as the stress-strain response and the shear strength profile inevitably influence the p-y and MR-θR springs, the applicability of the empirical formulations to soil conditions other than those examined is uncertain. This study proposes an enhancement to the ‘p-y + MR-θR’ framework, in which the p-y and MR-θR springs are not tied to a specific soil and strength profile but fundamentally linked to the properties that can be measured directly in the site investigation and laboratory. This extension is achieved through analytical analyses and an extensive parametric numerical study. The predictive capabilities of the model are demonstrated by back-analyses of finite element analyses and centrifuge model tests. The proposed model provides practising engineers with a simple yet powerful approach to use site-specific soil reaction curves in the design of monopiles embedded in soft clay.

A computational study on the uncertainty quantification of failure of clays with a modified Cam-Clay yield criterion

Abstract: In this study, the quantitative effect of the random distribution of the soil material properties to the probability density functions of the failure load and displacements is presented. A modified Cam-Clay failure criterion is embedded into a stochastic finite element numerical tool for this purpose. Various assumptions for the random distribution of the compressibility factor $$\kappa$$ , of the constitutive relation, the critical state line inclination c of the soil, and the permeability k have been tested and assessed with Latin hypercube sampling followed by Monte Carlo simulation. It is confirmed that both failure load and displacements follow Gaussian normal distribution despite the nonlinearity of the problem. Moreover, as the soil depth increases the mean value of failure load decreases and the failure displacement increases. Consequently, failure mechanism of clays can be determined in this work within an acceptable variability, taking into account the soil depth and nonlinear constitutive relations which in the analytical solutions is not feasible as it is assumed the Meyerhoff theory which considers the elastic halfspace.