How Small Strain Stiffness and Yield Surface Affect Undrained Excavation Predictions

Hsieh, Yu‐Ming; Dang, Phuoc H.; Lin, Huapeng

doi:10.1061/(asce)gm.1943-5622.0000753

Cited by 16 publications

(2 citation statements)

References 17 publications

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“…Small strain characteristics of soil should be considered to better predict the ground settlement mechanism. The Hardening soil with a small-strain (HS small) model could significantly enhance the reliability of deep excavation analysis [39], [40]. Therefore, the nonlinear behavior of sand was simulated using the HS small strain soil model under drained conditions to assess the settlements on the long term.…”

Section: Constitutive Model and Model Parametersmentioning

confidence: 99%

Performance of Pile Group Affected by Adjacent Excavations in Sand below the Water Table

Shaaban,

Abd El-Naiem,

Senoon

et al. 2024

Sohag Engineering Journal

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Numerical analysis is conducted to investigate the settlement and tilting behavior of a group of piles adjacent to an excavation in saturated sand by using PLAXIS 3D finite element software. Moreover, the analysis aims to gain a better understanding of the load transfer mechanisms of the piled foundations due to an adjacent excavation. The influences of excavation depth, pile group location from excavation, initial working load, supporting system stiffness, and stiffness of piles and cap are investigated. As excavation proceeds, settlement and tilting of the adjacent buildings can be observed at different stages of excavation. The pile group settles to its maximum amount when the rear piles are in the position of maximum greenfield ground surface settlement. The settlement of the pile group can be significantly reduced by increasing the supporting system stiffness and decreasing the pile cap's applied load. The pile group settlement due to the excavation increases from 2.99 to 3.80% of the pile diameter when the ratio of applied load to ultimate load-carrying capacity of the pile group increases from 0.25 to 0.5. A clearly noticeable tilting can be observed when the pile group is located near the excavation. By increasing the pile cap's applied load and supporting system stiffness, the pile group tilting decreases. The settlement and tilting of the pile group are almost insensitive to the modulus of elasticity of the concrete piles and the cap. Loads are transferred between the toe and the shaft of the piles at different excavation stages.

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Section: Constitutive Model and Model Parametersmentioning

confidence: 99%

Performance of Pile Group Affected by Adjacent Excavations in Sand below the Water Table

Shaaban,

Abd El-Naiem,

Senoon

et al. 2024

Sohag Engineering Journal

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“…S-CLAY1S was chosen to keep the model simple, but there are more advanced constitutive models for soft clays that, for example, introduce some flexibility in the shape of the plastic potential [ 14 ] or use a non-associated flow rule [ 18 , 19 ]. Some other advanced features of clay behavior, such as creep [ 20 ] or small-strains [ 21 ], have not been here considered either.…”

Section: S-clay1s Modelmentioning

confidence: 99%

A Constitutive Model for Soft Clays Incorporating Elastic and Plastic Cross-Anisotropy

Castro

Sivasithamparam

2017

Materials

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Natural clays exhibit a significant degree of anisotropy in their fabric, which initially is derived from the shape of the clay platelets, deposition process and one-dimensional consolidation. Various authors have proposed anisotropic elastoplastic models involving an inclined yield surface to reproduce anisotropic behavior of plastic nature. This paper presents a novel constitutive model for soft structured clays that includes anisotropic behavior both of elastic and plastic nature. The new model incorporates stress-dependent cross-anisotropic elastic behavior within the yield surface using three independent elastic parameters because natural clays exhibit cross-anisotropic (or transversely isotropic) behavior after deposition and consolidation. Thus, the model only incorporates an additional variable with a clear physical meaning, namely the ratio between horizontal and vertical stiffnesses, which can be analytically obtained from conventional laboratory tests. The model does not consider evolution of elastic anisotropy, but laboratory results show that large strains are necessary to cause noticeable changes in elastic anisotropic behavior. The model is able to capture initial non-vertical effective stress paths for undrained triaxial tests and to predict deviatoric strains during isotropic loading or unloading.

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Small Strains in Soil Constitutive Modeling

Castellón

Ledesma

2022

Arch Computat Methods Eng

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This paper reviews the state of the art of soil behavior in the range of small strains and its constitutive modeling, which is an important issue when predicting displacements under serviceability conditions. The factors that control nonlinear, hysteretic and dependent on recent history soil behavior are described. Likewise, concepts of soil constitutive modeling are explored in detail and two criteria are explained and used to classify the analyzed models: (1) a first criterion based on the concept of tensorial zones; and (2) a second criterion based on the elements that defines the hysteretic soil behavior, including reversal criteria, memory rules and the effects of reversals on soil degradation and on soil stiffness recovery. The fundamentals of the formulation of the analyzed models are provided, as well as their scope of application, advantages and disadvantages.

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How Small Strain Stiffness and Yield Surface Affect Undrained Excavation Predictions

Cited by 16 publications

References 17 publications

Performance of Pile Group Affected by Adjacent Excavations in Sand below the Water Table

Performance of Pile Group Affected by Adjacent Excavations in Sand below the Water Table

A Constitutive Model for Soft Clays Incorporating Elastic and Plastic Cross-Anisotropy

Small Strains in Soil Constitutive Modeling

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