Experimental investigation and constitutive modeling of the behaviour of highly plastic Lower Rhine Clay under monotonic and cyclic loading

2020 ◽  
Author(s):  
Merita Tafili ◽  
Torsten Wichtmann ◽  
Theodoros Triantafyllidis
Keyword(s):  
Cyclic Loading ◽  
Large Strain ◽  
Constitutive Models ◽  
Rate Dependency ◽  
Final Phase ◽  
Inherent Anisotropy ◽  
Fine Grained ◽  
Cyclic Mobility ◽  
Isotropic Consolidation ◽  
Lower Rhine

A new experimental series on the highly plastic (I_P = 34 %) Lower Rhine Clay (LRC) is presented. The study comprises tests on normally as well as over consolidated samples under monotonic and cyclic loading. The loading velocity has been varied in order to evaluate the strain rate dependency of the LRC behaviour testifying i.a. the well-known reduction of undrained shear strength with decreasing displacement rate. Isotropic consolidation followed by a cyclic loading with constant deviatoric stress amplitude leads to a failure due to large strain amplitudes with eight-shaped effective stress paths in the final phase of the tests. The inherent anisotropy has been additionally evaluated using samples cut out in either the vertical or the horizontal direction. Furthermore, the behaviour of LRC is compared with the behaviour of low plastic Kaolin silt (I_P = 12:2 %). A new visco-hypoplastic-type constitutive model with a historiotropic yield surface has been used to simulate some of the experiments with cyclic loading. Even the eight-shaped stress loops at cyclic mobility are reproduced well with this model. The data of this paper can be also used by other researchers for the examination, calibration, improvement or development of constitutive models dedicated to fine-grained soils under monotonic and cyclic loading.

scholarly journals Elaborated subloading surface model for accurate description of cyclic mobility in granular materials

2021 ◽  
Author(s):  
Koichi Hashiguchi ◽  
Tatsuya Mase ◽  
Yuki Yamakawa
Keyword(s):  
Cyclic Loading ◽  
Granular Materials ◽  
Accurate Description ◽  
Surface Model ◽  
Cyclic Mobility ◽  
Mixed Hardening ◽  
Hardening Rule ◽  
Elastic Domain ◽  
Translation Rule ◽  
Rotational Hardening

AbstractThe description of the cyclic mobility observed prior to the liquefaction in geomaterials requires the sophisticated constitutive formulation to describe the plastic deformation induced during the cyclic loading with the small stress amplitude inside the yield surface. This requirement is realized in the subloading surface model, in which the surface enclosing a purely elastic domain is not assumed, while a purely elastic domain is assumed in other elastoplasticity models. The subloading surface model has been applied widely to the monotonic/cyclic loading behaviors of metals, soils, rocks, concrete, etc., and the sufficient predictions have been attained to some extent. The subloading surface model will be elaborated so as to predict also the cyclic mobility accurately in this article. First, the rigorous translation rule of the similarity center of the normal yield and the subloading surfaces, i.e., elastic core, is formulated. Further, the mixed hardening rule in terms of volumetric and deviatoric plastic strain rates and the rotational hardening rule are formulated to describe the induced anisotropy of granular materials. In addition, the material functions for the elastic modulus, the yield function and the isotropic hardening/softening will be modified for the accurate description of the cyclic mobility. Then, the validity of the present formulation will be verified through comparisons with various test data of cyclic mobility.

Residual shear strength of fine-grained soils and soil–solid interfaces at low effective normal stresses

2015 ◽  
Vol 52 (2) ◽  
pp. 198-210 ◽  
Author(s):  
Hisham T. Eid ◽  
Ruslan S. Amarasinghe ◽  
Khaled H. Rabie ◽  
Dharma Wijewickreme
Keyword(s):  
Shear Strength ◽  
Large Strain ◽  
Laboratory Research ◽  
Normal Stresses ◽  
Interface Shear ◽  
Residual Shear Strength ◽  
Fine Grained ◽  
Solid Interface ◽  
Wide Range ◽  
Shear Area

A laboratory research program was undertaken to study the large-strain shear strength characteristics of fine-grained soils under low effective normal stresses (∼3–7 kPa). Soils that cover a wide range of plasticity and composition were utilized in the program. The interface shear strength of these soils against a number of solid surfaces having different roughness was also investigated at similar low effective normal stress levels. The findings contribute to advancing the knowledge of the parameters needed for the design of pipelines placed on sea beds and the stability analysis of shallow soil slopes. A Bromhead-type torsional ring-shear apparatus was modified to suit measuring soil–soil and soil–solid interface residual shear strengths at the low effective normal stresses. In consideration of increasing the accuracy of assessment and depicting the full-scale field behavior, the interface residual shear strengths were also measured using a macroscale interface direct shear device with a plan interface shear area of ∼3.0 m2. Correlations are developed to estimate the soil–soil and soil–solid interface residual shear strengths at low effective normal stresses. The correlations are compared with soil–soil and soil–solid interface drained residual shear strengths and correlations presented in the literature.

scholarly journals Numerical Modeling of Masonry-infilled RC Frame

2019 ◽  
Vol 13 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Christiana A. Filippou ◽  
Nicholas C. Kyriakides ◽  
Christis Z. Chrysostomou
Keyword(s):  
Cyclic Loading ◽  
Numerical Model ◽  
Constitutive Models ◽  
Control Analysis ◽  
Rc Frame ◽  
Initial Stiffness ◽  
Element Analysis ◽  
Rc Frames ◽  
Rc Frame Structures ◽  
Infilled Rc Frames

Background: The behavior of masonry-infilled Reinforced Concrete (RC) frame structures during an earthquake, has attracted the attention of structural engineers since the 1950s. Experimental and numerical studies have been carried out to investigate the behavior of masonry-infilled RC frame under in-plane loading. Objective: This paper presents a numerical model of the behavior existing masonry-infilled RC frame that was studied experimentally at the University of Patra. The objective of the present study is to identify suitable numerical constitutive models for each component of the structural system in order to create a numerical tool to model the masonry infilled RC frames in-plane behavior by accounting the frame-infill separation. Methods: A 2D masonry-infilled RC frame was developed in DIANA Finite Element Analysis (FEA) software and an eigenvalue and nonlinear structural cyclic analyses were performed. It is a 2:3 scale three-story structure with non-seismic design and detailing, subjected to in-plane cyclic loading through displacement control analysis. Results: There is a good agreement between the numerical model and experimental results through a nonlinear cyclic analysis. It was found that the numerical model has the capability to predict the initial stiffness, the ultimate stiffness, the maximum shear-force capacity, cracking- patterns and the possible failure mode of masonry-infilled RC frame. Conclusion: Therefore, this model is a reliable model of the behavior of masonry-infilled RC frame under cyclic loading including the frame-infill separation (gap opening).

Effect of Inherent Anisotropy on the Behavior of Fine-Grained Cohesive Soils

2018 ◽  
Vol 17 (6) ◽  
pp. 687-697 ◽  
Author(s):  
Chia Zarei ◽  
Hossein Soltani-Jigheh ◽  
Kazem Badv
Keyword(s):  
Cohesive Soils ◽  
Inherent Anisotropy ◽  
Fine Grained

A Comparative Study of the Response of Double Shearing and Hypoplastic Models

2002 ◽  
Author(s):  
Huaning Zhu ◽  
Morteza M. Mehrabadi ◽  
Mehrdad Massoudi
Keyword(s):  
Cyclic Loading ◽  
Mechanical Response ◽  
Constitutive Relations ◽  
Constitutive Models ◽  
Shear Loading ◽  
Biaxial Compression ◽  
Finite Element Program ◽  
Cyclic Shear ◽  
Hypoplastic Model ◽  
Element Program

The principal objective of this paper is to compare the mechanical response of a double shearing model with that of a hypoplastic model under biaxial compression and under cyclic shear loading. As the origins and nature of these two models are completely different, it is interesting to compare the predictions of these two models. The constitutive relations of the double shearing and the hypoplastic models are implemented in the finite element program ABACUS/Explicit. It is found that the hypoplastic and the double shearing constitutive models both show strong capability in capturing the essential behavior of granular materials. In particular, under the condition of non-cyclic loading, the stress ratio and void ratio predictions of the double shearing and the hypoplastic models are relatively close, while under the condition of cyclic loading, the predictions of these models are quite different. It is important to note that in the double shearing model employed in this comparison the shear rates on the two slip systems are assumed to be equal. Hence, the conclusions derived in this comparison pertain only to this particular double shearing model. Similarly, the hypoplasticity model considered here is that proposed by Wu, et al. [30] and the conclusions reached here pertain only to this particular hypoplasticity model.

A Historical Overview of Design Analyses and Experimental Observations of Ratcheting Phenomenon

2020 ◽  
Author(s):  
Jean Macedo ◽  
Stéphane Chapuliot ◽  
Jean-Michel Bergheau ◽  
Eric Feulvarch ◽  
Olivier Ancelet ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
State Of The Art ◽  
Constitutive Models ◽  
Experimental Tests ◽  
Design Codes ◽  
Historical Overview ◽  
Design Rules ◽  
Current Article ◽  
The Difference ◽  
Design Analyses

Abstract In order to investigate the ratcheting behavior and to determine new design rules, some experimental tests were conducted in many countries in the last decades. In France, some tests were carried out under mechanical or thermal cyclic loading to examine this risk. The first section of the current article is addressed to the state of the art concerning the ratcheting effects. The difference between Local and Global Ratcheting is clarified. The second section is dedicated to the experimental observations of ratcheting. The following section describes the constitutive models which are able to simulate material/structural ratcheting responses. The models presented are Linear Kinematic, Armstrong-Frederick, Chaboche, Ohno-Wang and Chen-Jiao-Kim. Finally, the ratcheting rules in design codes are exposed. Both simple and complex rules are presented.

scholarly journals Modelling of undrained shearing of soft natural clays

2019 ◽  
Vol 92 ◽  
pp. 15001
Author(s):  
Alexandros L. Petalas ◽  
Mats Karlsson ◽  
Minna Karstunen
Keyword(s):  
Triaxial Compression ◽  
Constitutive Models ◽  
Strain Response ◽  
Rate Dependency ◽  
Induced Anisotropy ◽  
Stress Strain ◽  
Soft Soils ◽  
Model Simulations ◽  
Rate Effects ◽  
Natural Clays

stress-strain response of soft natural clays is characterised by anisotropy, destructuration and rate-dependency. An accurate constitutive description of these materials should take into consideration all of the characteristics above. In this paper, two constitutive models for soft soils, namely the SCLAY1S and Creep-SCLAY1S models are used to simulate the undrained response of two soft natural clays, Gothenburg clay from Sweden and Otaniemi clay from Finland. The SCLAY1S model accounts for the effect of inherent and induced anisotropy and destructuration, while the Creep-SCLAY1S accounts also for the creep and rate effects. The model simulations are compared against triaxial compression and extension tests on anisotropically consolidated samples. The results demonstrate the need to incorporate all features represented in the Creep-SCLAY1S model when modelling structured natural clays.

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