A new model for wave-induced instantaneous liquefaction in a non-cohesive seabed with dynamic permeability

OCEAN ENGINEERING

卷:213

Article

Zhou, Mo-Zhen¹  Jeng, Dong-Sheng²  Qi, Wen-Gang^3,4 

[1] Beijing Jiaotong Univ, Key Lab Urban Underground Engn, Minist Educ, Beijing 100044, Peoples R China

[2] Griffith Univ, Sch Engn & Built Environm, Gold Coast Campus, Gold Coast, Qld 4222, Australia

[3] Chinese Acad Sci, Inst Mech, Key Lab Mech Fluid Solid Coupling Syst, Beijing 100190, Peoples R China

[4] Univ Chinese Acad Sci, Sch Engn Sci, Beijing 100049, Peoples R China

关键词: Dynamic permeability;    Excess pore pressure;    Soil liquefaction;    Wave-seabed interaction;   

DOI  :  10.1016/j.oceaneng.2020.107597

来源: Elsevier

【 摘 要 】

Wave-induced instantaneous liquefaction is crucial to evaluating the stability of offshore foundations. For the instantaneous liquefaction, most previous studies treated the seabed as an invariant poro-elastic medium and hence led to nonphysical tensile stress in the non-cohesive liquefied zone. In this study, a penalty-like dynamic permeability model is proposed, based on the experimental evidences of permeability increase during soil liquefaction. The nonlinearity induced by the dynamic permeability is solved by an iterative procedure, based on the Newton-Raphson method. The numerical procedure is implemented in an in-house code and compared with analytical solutions under the constant permeability assumption. Numerical observations validate that the proposed dynamic permeability model can alleviate or even eliminate the nonphysical tensile stress in the instantaneously-liquefied zone. In contrast to the constant permeability model, the new model with a dynamic permeability obtains a better agreement with existing cylinder tests under one-dimensional wave loading conditions. For the numerical examples presented, the liquefaction depths predicted by constant permeability can be up to twice of those by the new dynamic permeability model. It is concluded that the conventional model with constant permeability overestimates the liquefaction potential.

【 授权许可】

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