Numerical Analysis of the Second Composite Ground

2011 ◽  
Vol 347-353 ◽  
pp. 725-732 ◽  
Author(s):  
Shu Li Wang ◽  
Dun Wu Chen ◽  
Ran Wang
Keyword(s):  
Soft Soil ◽  
Volumetric Strain ◽  
Horizontal Displacement ◽  
Reduction Factor ◽  
Stone Columns ◽  
Strength Reduction Factor ◽  
Maximum Shear Strain ◽  
Element Analysis ◽  
Numerical Predictions ◽  
Composite Ground

The behavior of a foundation built on normally consolidated soft soil reinforced with stone columns (SC) and deep mixing columns (DMC) is studied using a finite element analysis program, Phase2D. The numerical predictions are analyzed in terms of absolute vertical displacement, absolute horizontal displacement, mean stresses, volumetric strain, maximum shear strain and strength reduction factor. Firstly, the effectiveness of the use of stone columns, the first composite ground, is studied. Afterwards, because load bearing capacity is less than 160 kPa designed, the effectiveness analysis reinforced with DMC, the second composite ground, is performed to study the influence on the soil-columns system of the foundation and columns.

Foundation Numerical Analysis on Soft Soil Reinforced with Stone Columns

2011 ◽  
Vol 94-96 ◽  
pp. 190-195 ◽  
Author(s):  
Shu Li Wang ◽  
Man Gen Mu ◽  
Jing Yu Dai ◽  
Xiao Huan Hu
Keyword(s):  
Numerical Analysis ◽  
Bearing Capacity ◽  
Design Method ◽  
Soft Soil ◽  
Volumetric Strain ◽  
Vertical Displacement ◽  
Area Ratio ◽  
Stone Columns ◽  
Mean Stress ◽  
Maximum Shear Strain

A parametric study of an foundation on soft soils reinforced with stone columns is performed using Phase2D. The real foundation is modeled and its bearing capacity is decided by the columns and their surrounding soft soil. The following parameters are analysed: the replacement area ratio, the deformability, mean stress, absolute horizontal (vertical) displacement, volumetric strain, maximum shear strain of the foundation. Based on the results of this study, a new design method is proposed: for decreasing the settlement and satisfying bearing capacity, increasing the replacement area ratio is good idea.

Analytical Study of Load-Settlement Behavior of Soil Treated with Stone Columns have Different Sectional Shape

2020 ◽  
Vol 857 ◽  
pp. 319-327
Author(s):  
Moataz A. Al-Obaydi ◽  
Zeena A. Al-Kazzaz
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
Engineering Properties ◽  
Stone Columns ◽  
Equivalent Diameter ◽  
Element Analysis ◽  
Cross Sectional ◽  
Treated Soil ◽  
Almost All ◽  
Sectional Shape

Stone columns have been used widely to improve the engineering properties of the weak soil. Most of the previous works considered a circular section for the stone columns. In the present study, finite element analysis has been carried out to investigate the effect of stone columns shape and length on the settlement and bearing capacity of soft soil. Accordingly, three types of cross sectional shape for stone columns have been selected which they are circular, rectangular, and square sections with equivalent area. Various length of columns are adopted with diameter of 0.75m that achieved length to diameter or equivalent diameter ratios (L/d=2, 4, 6, 8, and 10) of columns spacing (S/d=3). The results show that the stone columns has tangible effects on the settlement of the soil while has minor effects on the bearing capacity. The settlement of the treated soil with stone columns have L/d=2, reduces by 18.0, 17.3, and 19.3% for circular, rectangular , and square sections respectively. With increasing length of the columns to L/d=10, further reductions in the settlement obtained of (27.1, 28.1, and 27.0%). Bearing capacity of the soil increased slightly with length of the stone columns. Almost all cross sectional shapes of the columns give bearing capacity about same. The increased in the bearing capacity of the treated soil with stone columns have L/d=2, not exceeded 10% for all sectional types. The average increments in bearing capacity when L/d=10 are 12 and 15% at settlement 50 and 100mm respectively. Insignificant changes in bearing capacity upon increasing length of columns from L/d=2 to 10 of maximum 5%. The plastic zone recedes with the increasing length of the stone columns. Finally, from the results obtained, it can be concluded that the stone columns shape has negligible effects on the settlement and bearing capacity of the soil.

Application of Two Methods for Notch Fatigue Life Prediction

2011 ◽  
Vol 488-489 ◽  
pp. 654-657
Author(s):  
Radu Negru ◽  
Liviu Marsavina ◽  
Hannelore Filipescu ◽  
Cristiana Caplescu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Reduction Factor ◽  
Volumetric Method ◽  
Life Assessment ◽  
Strength Reduction Factor ◽  
Element Analysis ◽  
Linear Elastic ◽  
Notched Specimens

The aim of this paper is the application of two methods for notch fatigue life assessment, methods which are based on finite element analysis: the theory of critical distances and the volumetric method. Firstly, un-notched and notched specimens (for three different geometries) were tested in tension under constant-amplitude loading. The use of theory of critical distances (TCD) to predict the notch fatigue life involves the determination of the material characteristic length L based on experimental results obtained for the un-notched and one type of notched specimens. For the others notched geometries, based on linear-elastic finite element analysis, the fatigue strength is predicted using the TCD. In order to apply the volumetric method, elastic-plastic stress field around notches are considered and notch strength reduction factor are determined. Finally, the predictions of the two methods were compared with experimental fatigue data for notched specimens.

Research on Inelastic Response Spectra for Asymmetric Plan Systems Subjected to Bi-Directional Earthquake Motions

2012 ◽  
Vol 166-169 ◽  
pp. 2332-2336
Author(s):  
Feng Wang ◽  
Hong Nan Li ◽  
Ting Hua Yi
Keyword(s):  
Soft Soil ◽  
Rotation Frequency ◽  
Response Spectra ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Inelastic Response ◽  
Surface Plasticity ◽  
Soil Site ◽  
Spectral Equation

The limitations of traditional inelastic response spectra are discussed. Considering a one-storey asymmetric plan system subjected to perpendicular bi-directional earthquake motions, the inelastic multi-dimensional strength reduction factor spectra is presented. The yield rule of the asymmetric plan system is determined by two-dimensional yield-surface plasticity function. The spectral equation is simplified by the relationship of strength reduction factors between x-direction and y-direction.The multi-dimensional spectra are analyzed based on 30 pair strong earthquake motion records for hard soil site, intermediate soil site and soft soil site. Analytic results shows that the strength reduction factor mean spectra for each soil site has its own characteristics, and the strength reduction factor spectra is affected strongly by ductility, normalized stiffness eccentricity, period and rotation frequency ratio.

scholarly journals The Impact of Using Different Types of Soft Soils Treated by Stone Columns on Creep Behavior

2022 ◽  
Vol 961 (1) ◽  
pp. 012052
Author(s):  
Sura Tawfeeq Al-Auqbi ◽  
Nahla M. Salim ◽  
Mahmood R. Mahmood
Keyword(s):  
Soft Soil ◽  
Horizontal Displacement ◽  
Cohesive Soil ◽  
Stone Columns ◽  
Stone Column ◽  
Geometric Conditions ◽  
Improvement Factor ◽  
Soil Deposits ◽  
Different Types ◽  
The Impact

Abstract The stone column technique is an effective method to increase the strength of soft cohesive soil, which results in a reduction in foundation settlement and an increase in bearing capacity. The topic of restraining creep settlement through the use of stone columns techniques has gained increasing attention and consideration; because stone columns are widely used to treat soft soil deposits, caution should be applied in estimating creep settlement. We discovered a reversible relation between shear parameters and the creep settlement in floating stone columns; while, in case of end-bearing stone columns shows a direct positive relation between shear parameters and the creep settlement, and the creep settlement began at the primary settlement. The shear parameters affected the improvement factor (n) of creep settlement in both floating and end-bearing stone columns. The standard creep coefficient’s n values in floating and end-bearing conditions were more significant than the low creep coefficient’s n values in forwarded geometric conditions. The stress in both floating and end-bearing stone columns was increasing and uniformly distributed along the length of the floating stone column and in the case of end-bearing stone column was limited to the stiffness layer; the maximum vertical stress was in the central point of the embankment. The embankment’s maximum horizontal displacement occurred on the edge.

scholarly journals FINITE ELEMENT ANALYSIS OF UNFASTENED COLD-FORMED STEEL CHANNEL SECTIONS WITH WEB HOLES UNDER END-TWO-FLANGE LOADING AT ELEVATED TEMPERATURES

2021 ◽  
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Reduction Factor ◽  
Strength Reduction Factor ◽  
Element Analysis ◽  
Study Results ◽  
Cold Formed Steel ◽  
Factor Equation

This paper presents the results of a finite element investigation on cold-formed steel (CFS) channel sections with circular web holes under end-two-flange (ETF) loading condition and subjected to elevated temperatures. The stress strain curve for G250 CFS with 1.95 mm thickness at elevated temperatures was taken from Kankanamge and Mahendran and the temperatures were considered up to 700 oC. To analyse the effect of web hole size and bearing length on the strength of such sections at elevated temperatures, a parametric study involving a total of 288 FE models was performed. The parametric study results were then used to assess the applicability of the strength reduction factor equation presented by Uzzaman et al. for CFS channel-sections with web holes under ETF loading from ambient temperature to elevated temperatures. It is shown that the reduction factor equation is safe and reliable at elevated temperatures.

scholarly journals Prediction the Behavior of Piles in Clayey Soils

2018 ◽  
Vol 7 (4.20) ◽  
pp. 157
Author(s):  
Hanan Adnan Hasan
Keyword(s):  
Ultimate Load ◽  
Lateral Displacement ◽  
Soft Soil ◽  
Reduction Factor ◽  
Interface Element ◽  
Clayey Soils ◽  
Ultimate Capacity ◽  
Element Analysis ◽  
Stiff Clays ◽  
Stiff Clay

This research includes a non- linear finite element analysis of axisymmetric soil-pile system. The analysis included piles of different length and diameter. The interface element was used as a thin layer separating the pile from surrounding soil. The load settlement curves for piles installed in soft to medium and stiff clays were obtained. Two consideration were studied; the ultimate capacity of pile and the settlement reduction factor. The results show that increase in the length and diameter of pile leads to increase in the ultimate load in range (35- 60%) and in the range (33- 35) % respectively. The distribution of lateral displacement along the depth of the pile gave the same trend in both soft to medium and stiff clay while the settlement reduction factor in soft soil is greater than for the stiff clay.   

The Numerical Analysis of Earth Pressure on Bucket Foundation Breakwater

2015 ◽  
Vol 744-746 ◽  
pp. 1194-1198
Author(s):  
Zhi Yun Wang ◽  
Xiao Long Ma ◽  
Lu Shen ◽  
Jing Lu
Keyword(s):  
Soft Soil ◽  
Three Dimensional ◽  
Engineering Application ◽  
Earth Pressure ◽  
Horizontal Displacement ◽  
General Purpose ◽  
Element Analysis ◽  
Bucket Foundation ◽  
Practical Engineering ◽  
The Stability

As a newly developed engineering structure, bucket foundation breakwater is adapted to soft soil. In this paper, the general-purpose finite element analysis package ABAQUS is employed to conduct three-dimensional numerical analyses on bucket foundation breakwater. Then earth pressure variation on bucket foundation is carried out under different loads of horizontal displacement. Through analysis it obtains the laws of the earth pressure on the meeting-wave side and the back-wave side of bucket foundation breakwater. This will provide the reference and the evidence of preliminary theory for the stability research and practical engineering application of bucket foundation breakwater.

scholarly journals Influence of granular material characteristics in the behaviour of “Bouregreg Valley” soft ground improved with stone columns

2018 ◽  
Vol 149 ◽  
pp. 02020
Author(s):  
Noura Nehab ◽  
Khadija Baba ◽  
Latifa Ouadif ◽  
Lahcen Bahi
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Granular Material ◽  
Complex Geometry ◽  
Soft Soil ◽  
Permanent Deformation ◽  
Stone Columns ◽  
Soil Conditions ◽  
Natural Soil ◽  
Element Analysis

The use of finite element analysis has become widespread in geotechnical practice as means of optimizing engineering tasks; it can be easily applied to the treated areas by stone columns, which are a method of improving the soil having low geotechnical properties and likely to deform significantly under load action, by incorporating granular material (commonly called ballast) compacted by remounting passes, so they act mainly as inclusions with a higher stiffness, shear strength than the natural soil. Moreover the stone columns are highly permeable and act as vertical drains facilitating consolidation of the soft soil improving the performance of the foundation. However the characteristics of this granular material influence the behavior of soft soils treated by the stone columns technique, especially: the friction angle, the cohesion, the modular ratio and the constitutive model. The choice of the constitutive model depends on many factors but, in general, it is related to the type of analysis that we intend to perform. Numerical modeling must consider the diversity of the materials nature, the complex geometry of structures-land and the behavior of materials generally nonlinear (permanent deformation). It is a simple and effective alternative to approach the real behavior of soils reinforced by stone columns and the influence of materials characteristics, it allows settlement analysis, lateral deformation, vertical and horizontal stresses in order to understand the behavior of columns and soil. It also has the advantage of integrating the settlements of the underlying layers. This paper aims to study the mechanisms of functioning and interactions of stone columns with the surrounding ground, and vis-à-vis the various parameters characterizing the granular material "ballast" and the surrounding soil, which influence the behavior of the improved soil, The paper presents, in the first part, soil conditions and the parameters associated with columns, is then presented 3D finite element analyses, so the parametric study was carried out varying several properties especially granular material properties.

Experimental and Analytical Study for Collapse Characteristics of 45 Deg Cylinder-to-Cylinder Intersections

2014 ◽  
Author(s):  
Shunji Kataoka ◽  
Takuya Sato ◽  
Takuro Honda ◽  
Masashi Takeda ◽  
Toshiya Tanimoto
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Stress ◽  
Stress Triaxiality ◽  
Local Stress ◽  
Reduction Factor ◽  
Stress Concentrations ◽  
Strength Reduction Factor ◽  
Element Analysis ◽  
Inelastic Analysis

The 45-degree laterals are widely used in pressure vessel nozzles and piping branch connections. Though the pressure design is always important for the 45-degree laterals, it is not a simple work because it has severe stress concentrations, it is difficult to weld and inspect, and there are some discrepancy between a conventional design and design by linear and nonlinear finite element analysis. In previous papers, authors studied the characteristics of both 90 degree tee and 45 degree laterals using an inelastic finite element analysis based on simplified shell element models and proposed Collapse Strength Reduction Factor (CSRF) based on an inelastic analysis were compared. In this paper, results of the burst test of 45-degree lateral and 90 degree intersection were shown. The fracture surface of 45-degree lateral was different from that of 90-degree intersection. These experimental results are compared with the inelastic finite element analysis results focusing on the local stress and strain behaviors. It was found that the magnitude of the local strain affected the burst pressure. Consideration should be given on the local failure due to excessive plastic strain under high stress triaxiality for the design of the 45-degree lateral by inelastic analysis.

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