scholarly journals Finite element analyses of energy piles using different constitutive models

2020 ◽  
Vol 205 ◽  
pp. 05013
Author(s):  
Chiara Iodice ◽  
Raffaele Di Laora ◽  
Alessandro Mandolini
Keyword(s):  
Finite Element ◽  
Constitutive Models ◽  
Single Pile ◽  
Finite Element Analyses ◽  
Energy Pile ◽  
State Of Stress ◽  
Modified Cam Clay ◽  
Energy Piles ◽  
Fully Coupled ◽  
Cam Clay

Energy piles are foundation elements having the double scope of transferring structural loads from the structure to the ground and of exchanging heat with the surrounding soil. It follows that pile state of stress and settlement are altered by the time-dependent temperature change in both pile and soil. This work is aimed at investigating the effect of thermal cycles on the behaviour of a single energy pile. To this end, fully coupled thermo-hydro-mechanical analyses have been carried out using the Finite Element code ABAQUS. The single pile is installed in a normally consolidated clay behaving according to different constitutive models involving Mohr-Coulomb, Modified Cam Clay and Hypoplastic. The latter is employed with and without the thermal formulation capable of accounting for the thermal collapse of NC clays during heating. A single free-head pile is considered and the results are presented in terms of pile axial force and settlement developed cycle by cycle.

scholarly journals Validation of a simple hypoplastic constitutive model for overconsolidated clays

2020 ◽  
Author(s):  
Shun Wang ◽  
Wei Wu
Keyword(s):  
Laboratory Tests ◽  
Constitutive Models ◽  
Standard Laboratory ◽  
Hypoplastic Model ◽  
Proposed Model ◽  
Modified Cam Clay ◽  
Overconsolidated Clays ◽  
Hypoplastic Constitutive Model ◽  
Comparison With Experiments ◽  
Cam Clay

AbstractHypoplastic constitutive models are able to describe history dependence using a single nonlinear tensorial function with a set of parameters. A hypoplastic model including a structure tensor for consolidation history was introduced in our previous paper (Wang and Wu in Acta Geotechnica, 2020, 10.1007/s11440-020-01000-z). The present paper focuses mainly on the model validation with experiments. This model is as simple as the modified Cam Clay model but with better performance. The model requires five parameters, which are easy to calibrate from standard laboratory tests. In particular, the model is capable of capturing the unloading behavior without introducing loading criteria. Numerical simulations of element tests and comparison with experiments show that the proposed model is able to reproduce the salient features of normally consolidated and overconsolidated clays.

scholarly journals RIGID PLASTIC FINITE ELEMENT METHOD USING MODIFIED CAM-CLAY MODEL

2017 ◽  
Vol 73 (2) ◽  
pp. I_333-I_342
Author(s):  
Yuki YAMAKURI ◽  
Shun-ichi KOBAYASHI ◽  
Jun SAITO ◽  
Tatsunori MATSUMOTO
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rigid Plastic ◽  
Clay Model ◽  
Modified Cam Clay ◽  
Cam Clay ◽  
Element Method

Coupled Finite Element Analysis of Partially Embedded Offshore Pipelines during Vertical Penetration

2014 ◽  
Vol 553 ◽  
pp. 428-433
Author(s):  
Yousef Ansari ◽  
George P. Kouretzis ◽  
Dai Chao Sheng
Keyword(s):  
Finite Element ◽  
Frictional Contact ◽  
Soil Consolidation ◽  
Element Analysis ◽  
Offshore Pipelines ◽  
Vertical Resistance ◽  
Number Of Factors ◽  
Modified Cam Clay ◽  
Consolidation Rate ◽  
Cam Clay

Diverse vertical embedment response is observed for partially embedded pipelines when experimentally tested under similar initial and boundary conditions. Although vertical resistance of pipelines is presented through simple analytical solutions, a number of factors contribute to complications in implementing these theories into practice. The objectives of this research is to provide a more detailed investigation on the vertical embedment for the partially-embedded pipelines (PEPs) using a coupled large deformation finite element (CLDFE) analysis with contact. A modified Cam Clay (MCC) model represents the elastoplastic response of the soil. The model of pipeline embedment investigates the effect of drainage condition on heave forming with respect to rate of penetration. Besides, effect of frictional contact on the heave development and wedging effect is investigated and design-related considerations are proposed. It is shown that depending on the rate of pipeline penetration and soil consolidation rate, the pipeline penetration response can be categorised as undrained, partially drained or fully drained.

Finite element analyses of negative skin friction on a single pile

2012 ◽  
Vol 7 (3) ◽  
pp. 239-252 ◽  
Author(s):  
Jinyuan Liu ◽  
Hongmei Gao ◽  
Hanlong Liu
Keyword(s):  
Finite Element ◽  
Skin Friction ◽  
Single Pile ◽  
Finite Element Analyses ◽  
Negative Skin Friction

Finite-element analysis of deep excavation in layered sandy and clayey soil deposits

1994 ◽  
Vol 31 (2) ◽  
pp. 204-214 ◽  
Author(s):  
Chang-Yu Ou ◽  
Ching-Her Lai
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Clayey Soil ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Deep Excavation ◽  
Element Analysis ◽  
Modified Cam Clay ◽  
Soil Deposits ◽  
Cam Clay

This paper presents an application of finite-element analysis to deep excavation in layered sandy and clayey soil deposits using a combination of the hyperbolic and the Modified Cam-clay models. In the analysis, the drained behavior of cohesionless soil and the undrained behavior of cohesive soil were simulated using the hyperbolic and Modified Cam-clay models, respectively. A rational procedure for determining soil parameters for each of the models was established. A simulation of the dewatering process during excavation was proposed. The analytical procedure was confirmed through an analysis of three actual excavation cases. Finally, analyses considering pore-water pressure dissipation during the actual elapsed time for each construction phase were carried out. The results indicate that the calculated displacement of a retaining wall during excavation is smaller than that given by undrained analysis. It was thought that some degree of pore-water pressure dissipation actually occurs during the intermediate excavation stages. This results in a decrease in the final deformation of the wall and ground.-surface settlement than would be predicted by undrained analysis. Key words : finite-element analysis, deep excavation, hyperbolic model, Cam-clay model.

Estimating long-term settlement of floating stone column groups

2014 ◽  
Vol 51 (7) ◽  
pp. 770-781 ◽  
Author(s):  
J.T. Shahu ◽  
Y.R. Reddy
Keyword(s):  
Finite Element ◽  
Soft Soil ◽  
Group Behavior ◽  
Stone Column ◽  
Finite Element Analyses ◽  
Modified Cam Clay ◽  
Single Column ◽  
Foundation Parameters ◽  
Column Group

Design charts for estimating long-term drained settlement of floating stone column group foundations are presented based on three-dimensional, elastoplastic, finite element analyses. In the analyses, the soft soil behavior is represented by the modified Cam-clay model while the stone column and mat are represented by the Mohr–Coulomb model. The finite element predictions are calibrated against model test results. A detailed parametric study of prototype stone column group foundations of various configurations is carried out to evaluate the relative importance of various foundation parameters on the group response. Next, finite element analyses of corresponding unit cells and single columns are performed. Reasonable correlations of load responses are found between single column and group behavior. Group and single column responses are then used to investigate Sg/S1 relationship with different foundation parameters, where Sg and S1 represent the settlement of the group and single column, respectively.

scholarly journals Study on arching effect in the embankment over pile - reinforced soft soil

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 19-25
Author(s):  
Hung Van Pham ◽  
Huy Quang Dang ◽  
Lam Phuc Dao ◽  
Long Khac Nguyen ◽  
Keyword(s):  
Stress Reduction ◽  
Soft Soil ◽  
Constitutive Models ◽  
Pile Group ◽  
3D Numerical Modeling ◽  
Soil Arching ◽  
Modified Cam Clay ◽  
Stress Concentration Ratio ◽  
Pile Group Effect ◽  
Cam Clay

The paper employes 3D numerical modeling to analyze the soil arching mechanism within embankment by FLAC3D code, based on the finite difference method (FDM). To consider the pile group effect, the 3D mesh of four pile has been created. Related to the constitutive models, the embankment is used Mohr - Coulomb model, the soft soil is represented by modified Cam - clay model, and footing and piles are employed by elasticity model. The numerical results focus on the soil arching phenomena in terms of stress distribution on piles and soft soil, the stress concentration ratio and the stress reduction ratio. Additionally, the axial force along pile and the settlements of embankment, soft soil and pile are studied.

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