Soil structure interaction analysis: modeling the interface

2002 ◽  
Vol 39 (3) ◽  
pp. 620-628 ◽  
Author(s):  
Morched Zeghal ◽  
Tuncer B Edil
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Laboratory Data ◽  
Contact Problems ◽  
Constitutive Law ◽  
Shear Stresses ◽  
Grain Crushing ◽  
Wide Range ◽  
Close Relationship ◽  
Element Technique

The sand–structure interface, developed under monotonic loading, was modeled based on physical observations. The model takes into account the macroscopic conditions to yield a general constitutive law applicable to a wide range of contact problems and the microstructural considerations constitute the specialization of the general equations to a specific problem. The surface of slippage was idealized to be sinusoidal based on an intensive numerical simulation program that made use of the discrete element technique. The model incorporates the effect of grain crushing found to play a major role in the behavior of the interface. Analysis of laboratory data revealed a close relationship between grain crushing and the work dissipated plastically during shear. The proposed elastoplastic model, requiring a limited number of parameters, predicts the shear stresses for the modified direct shear test and reproduces the shaft resistance of the shaft–sand interface pullout tests in a satisfactory manner.Key words: sand-structure interface, microstructure, grain crushing, plastic work.

Jointed Masonry Model: A constitutive law for 3D soil-structure interaction analysis

2019 ◽  
Vol 201 ◽  
pp. 109803 ◽  
Author(s):  
Wanda G. Lasciarrea ◽  
Angelo Amorosi ◽  
Daniela Boldini ◽  
Gianmarco de Felice ◽  
Marialaura Malena
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Constitutive Law ◽  
Soil Structure Interaction ◽  
Structure Interaction

2D and 3D CFD Investigations of Seabed Shear Stresses Around Subsea Pipelines

2013 ◽  
Author(s):  
Wenwen Shen ◽  
Terry Griffiths ◽  
Mengmeng Xu ◽  
Jeremy Leggoe
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Interaction Model ◽  
Suspended Sediment Transport ◽  
Shear Stresses ◽  
Parametric Function ◽  
Ample Evidence ◽  
North West ◽  
Wide Range ◽  
Subsea Pipelines

For well over a decade it has been widely recognised that existing models and tools for subsea pipeline stability design fail to account for the fact that seabed soils tend to become mobile well before the onset of pipeline instability. Despite ample evidence obtained from both laboratory and field observations that sediment mobility has a key role to play in understanding pipeline/soil interaction, no models have been presented previously which account for the tripartite interaction between the fluid and the pipe, the fluid and the soil, and the pipe and the soil. There are numerous well developed and widely used theories available to model pipe-fluid and pipe-soil interactions. A challenge lies in the way to develop a satisfactory fluid-soil interaction algorithm that has the potential for broad implementation under both ambient and extreme sea conditions due to the complexity of flow in the vicinity of a seabed pipeline or cable. A widely used relationship by Shields [1] links the bedload and suspended sediment transport to the seabed shear stresses. This paper presents details of computational fluid dynamics (CFD) research which has been undertaken to investigate the variation of seabed shear stresses around subsea pipelines as a parametric function of pipeline spanning/embedment, trench configuration and wave/current properties using the commercial RANS-based software ANSYS Fluent. The modelling work has been undertaken for a wide range of seabed geometries, including cases in 3D to evaluate the effects of finite span length, span depth and flow attack angle on shear stresses. These seabed shear stresses have been analysed and used as the basis for predicting sediment transport within the Pipe-Soil-Fluid (PSF) Interaction Model [2] in determining the suspended sediment concentration and the advection velocity in the vicinity of pipelines. The model has significant potential to be of use to operators who struggle with conventional stabilisation techniques for the pipelines, such as those which cross Australia’s North West Shelf, where shallow water depths, highly variable calcareous soils and extreme metocean conditions driven by frequent tropical cyclones result in the requirement for expensive and logistically challenging secondary stabilisation measures.

State-of-the-Art Techniques for Seismic Soil-Structure Interaction Analysis of Steel Gravity Structures

2014 ◽  
Author(s):  
Frederick Tajirian ◽  
Mansour Tabatabaie ◽  
Basilio Sumodobila ◽  
Stephen Paulson ◽  
Bill Davies
Keyword(s):  
Soil Structure ◽  
State Of The Art ◽  
Interaction Analysis ◽  
Layered Soil ◽  
Soil Structure Interaction ◽  
Soil System ◽  
Cyclonic Storm ◽  
Structure Interaction ◽  
Analysis Methods ◽  
Moderate Seismicity

The design of steel jacket fixed offshore structures in zones of moderate seismicity is typically governed by Metocean loads. In contrast the steel gravity structure (SGS) presented in this paper, is a heavy and stiff structure. The large mass results in foundation forces from seismic events that may exceed those created by extreme cyclonic storm events. When computing the earthquake response of such structures it is essential to account for soil-structure interaction (SSI) effects. Seismic SSI analysis of the SGS platform was performed using state-of-the-art SSI software, which analyzed a detailed three-dimensional model of the SGS supported on layered soil system. The results of this analysis were then compared with those using industry standard impedance methods whereby the layered soil is replaced by equivalent foundation springs (K) and damping (C). Differences in calculated results resulting from the different ways by which K and C are implemented in different software are presented. The base shear, overturning moment, critical member forces and maximum accelerations were compared for each of the analysis methods. SSI resulted in significant reduction in seismic demands. While it was possible to get reasonable alignment using the different standard industry analysis methods, this was only possible after calibrating the KC foundation model with software that rigorously implements SSI effects. Lessons learned and recommendations for the various methods of analysis are summarized in the paper.

Strain-Rate Effect on the Tensile Behaviour of High Strength Alloys

2011 ◽  
Vol 82 ◽  
pp. 124-129 ◽  
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni ◽  
Stefano Bianchi
Keyword(s):  
Strain Rate ◽  
Rate Sensitivity ◽  
High Strength ◽  
Constitutive Law ◽  
Tensile Behaviour ◽  
Strain Rates ◽  
Cross Sectional ◽  
Split Hopkinson Tensile Bar ◽  
Wide Range ◽  
First Results

In this paper the first results of the mechanical characterization in tension of two high strength alloys in a wide range of strain rates are presented. Different experimental techniques were used for different strain rates: a universal machine, a Hydro-Pneumatic Machine and a JRC-Split Hopkinson Tensile Bar. The experimental research was developed in the DynaMat laboratory of the University of Applied Sciences of Southern Switzerland. An increase of the stress at a given strain increasing the strain-rate from 10-3 to 103 s-1, a moderate strain-rate sensitivity of the uniform and fracture strain, a poor reduction of the cross-sectional area at fracture with increasing the strain-rate were shown. Based on these experimental results the parameters required by the Johnson-Cook constitutive law were determined.

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