Application of LRBF-DQ and CVBFEM Methods for Evaluating Saturated Sand Liquefaction around Buried Pipeline

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Saman Soleimani Kutanaei ◽  
Asskar Janalizadeh Choobbasti ◽  
Alireza Fakhrabadi ◽  
Moein Ghadakpour ◽  
Ali Vafaei ◽  
...  
Keyword(s):  
Buried Pipeline ◽  
Saturated Sand ◽  
Sand Liquefaction

scholarly journals Vertical ground motion and its effects on liquefaction resistance of fully saturated sand deposits

2016 ◽  
Vol 472 (2192) ◽  
pp. 20160434 ◽  
Author(s):  
Vasiliki Tsaparli ◽  
Stavroula Kontoe ◽  
David M. G. Taborda ◽  
David M. Potts
Keyword(s):  
Vertical Component ◽  
Vertical Motion ◽  
Soil Liquefaction ◽  
Elastic Response ◽  
Saturated Sand ◽  
Liquefaction Resistance ◽  
Sand Liquefaction ◽  
Variable Permeability ◽  
Lower Amplitude ◽  
Input Motion

Soil liquefaction has been extensively investigated over the years with the aim to understand its fundamental mechanism and successfully remediate it. Despite the multi-directional nature of earthquakes, the vertical seismic component is largely neglected, as it is traditionally considered to be of much lower amplitude than the components in the horizontal plane. The 2010–2011 Canterbury earthquake sequence in New Zealand is a prime example that vertical accelerations can be of significant magnitude, with peak amplitudes well exceeding their horizontal counterparts. As research on this topic is very limited, there is an emerging need for a more thorough investigation of the vertical motion and its effect on soil liquefaction. As such, throughout this study, uni- and bidirectional finite-element analyses are carried out focusing on the influence of the input vertical motion on sand liquefaction. The effects of the frequency content of the input motion, of the depth of the deposit and of the hydraulic regime, using variable permeability, are investigated and exhaustively discussed. The results indicate that the usual assumption of linear elastic response when compressional waves propagate in a fully saturated sand deposit does not always hold true. Most importantly post-liquefaction settlements appear to be increased when the vertical component is included in the analysis.

Numerical Simulation of Pile-Soil Interaction Considering Sand Liquefaction under Earthquake

2012 ◽  
Vol 226-228 ◽  
pp. 1019-1022 ◽  
Author(s):  
Pei Zhen Li ◽  
Dong Ya Ma ◽  
Da Ming Zeng ◽  
Xi Lin Lu
Keyword(s):  
Numerical Simulation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Clay ◽  
Soil Liquefaction ◽  
Engineering Practice ◽  
Saturated Sand ◽  
Acceleration Response ◽  
Sand Liquefaction ◽  
Vibration Time

Liquefaction is one of the most important damages in pile foundation under earthquake. However, it is very difficult to analyze. Numerical simulation of pile-soil interaction considering saturated sand liquefaction under earthquake is conducted using OpenSees program. In this model, the soil is divided into soft clay soil and saturated sand, and the single pile is embedded in the soil. The results show that the pore water pressure rises and the soil liquefied as vibration time increases. With the nonlinear of the soil develop, the stiffness, bearing capacity and the acceleration response of the soil and the pile decrease, while the displacement response of the soil increases. Therefore, it is necessary to consider the soil liquefaction in the design and analysis in the engineering practice.

Instability and liquefaction of granular soils under undrained and partially drained states

1998 ◽  
Vol 35 (6) ◽  
pp. 1053-1062 ◽  
Author(s):  
Y P Vaid ◽  
A Eliadorani
Keyword(s):  
Experimental Investigation ◽  
Triaxial Test ◽  
Void Ratio ◽  
Granular Soils ◽  
Saturated Sand ◽  
Stress Space ◽  
Sand Liquefaction ◽  
Undrained Shear

An experimental investigation of the initiation of instability (liquefaction) in saturated sand under partially drained conditions is presented. The domain of stress space in which this instability develops is identified under various degrees of drainage, and its relationship to the zone of instability observed under undrained shear is explored. It is shown that partially drained conditions may render sand unstable that would otherwise be stable in a completely undrained state. Extremely small void ratio increases that cannot be regarded as physical loosening of sand, if sand is partially drained, contribute to instability. Implications of the findings are discussed in practical problems of liquefaction.Key words: sand, liquefaction, undrained, partially drained, instability, triaxial test.

A Discrimination Method of Saturated Sand Liquefaction Possibility Based on Support Vector Machine

2014 ◽  
Vol 509 ◽  
pp. 38-43
Author(s):  
Zhong Jie Fan ◽  
Yan Qiu Leng ◽  
Yong Long Xu ◽  
Zheng Jiang Meng ◽  
Ji Wei Xu
Keyword(s):  
Support Vector Machine ◽  
Influence Factors ◽  
Kernel Functions ◽  
Small Sample ◽  
Support Vector ◽  
Saturated Sand ◽  
Risk Minimization ◽  
Sand Liquefaction ◽  
Discriminant Model ◽  
Svm Model

Based on the analysis of influence factors of saturated sand, this paper expounds the limitations of traditional evaluation of liquefaction, and introduces the criterion of support vector machine (SVM) based on the principle of structural risk minimization. According to the main influence factors of sand liquefaction, a SVM discriminant model of sand liquefaction with different kernel functions is established. Through studying small sample data, this model can establish nonlinear mapping relationship between influence factors and liquefaction type. On the basis of seismic data, a radial based kernel function is selected to predict sand liquefaction type. The research results show that the predicted magnitude is identical with the actual result, to prove that it is effective to apply this SVM model to evaluate the level of sand liquefaction.

Development of the mathematical model for assessing the optimal measurement step when surveying the depth of the underground pipeline from the ground

2020 ◽  
Vol 10 (4) ◽  
pp. 364-371
Author(s):  
Ruslan V. Aginey ◽  
◽  
Rustem R. Islamov ◽  
Alexey A. Firstov ◽  
Elmira A. Mamedova ◽  
...  
Keyword(s):  
Mathematical Models ◽  
Survey Data ◽  
Ground Surface ◽  
Maximum Error ◽  
Large Error ◽  
Bending Stress ◽  
Buried Pipeline ◽  
Optimal Measurement ◽  
Pipeline Section ◽  
Bending Stresses

Existing methods for estimating the bending stresses of buried pipeline section based on the survey data for the depth of the axis of the pipeline from the ground surface are characterized by a large error between the real values of the bending stress and the values of the bending stress obtained from the calculation results based on the survey data. The purpose of this study is to improve the methodology for calculating the bending stresses of buried pipeline section based on the results of determining the depth of the axis of the pipeline from the ground surface, taking into account the design features of the pipeline and the used search equipment. Mathematical models are proposed that allow for the set value of the maximum error in determining bending stresses for a particular pipeline to choose the optimal measurement step before the survey, which will allow to reduce the error. Explanations are given on the choice of the maximum step of the study based on the strength characteristics of the pipeline. A calculation is provided that confirms the adequacy of the developed mathematical models and the possibility of their application in practice.

Effect of the loading frequency on the sand liquefaction behaviour in cyclic triaxial tests

2021 ◽  
Vol 147 ◽  
pp. 106779
Author(s):  
Zhehao Zhu ◽  
Feng Zhang ◽  
Qingyun Peng ◽  
Jean-Claude Dupla ◽  
Jean Canou ◽  
...  
Keyword(s):  
Triaxial Tests ◽  
Loading Frequency ◽  
Cyclic Triaxial ◽  
Cyclic Triaxial Tests ◽  
Sand Liquefaction
Sign in / Sign up

Export Citation Format

Share Document