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.

Embankments on Soft Soil Reinforced with Stone Columns: Numerical Analysis and Proposal of a New Design Method

2009 ◽  
Vol 27 (6) ◽  
pp. 667-679 ◽  
Author(s):  
José Leitão Borges ◽  
Tiago Sabino Domingues ◽  
António Silva Cardoso
Keyword(s):  
Numerical Analysis ◽  
Design Method ◽  
Soft Soil ◽  
Stone Columns

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.

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 Long-Short-Pile Composite Foundation of High-Rise Building in Soft Soil

2012 ◽  
Vol 256-259 ◽  
pp. 57-60
Author(s):  
Rong Fang Song ◽  
Ling Yun Lang ◽  
Jing Wang
Keyword(s):  
Bearing Capacity ◽  
Calculation Method ◽  
Design Method ◽  
Soft Soil ◽  
Composite Foundation ◽  
Soft Ground ◽  
Design Calculation ◽  
Actual Measurement ◽  
High Rise ◽  
High Rise Building

A case of the long-short-pile composite foundation in liquefied soft soil under a 30-storey high-rise building is presented, in which the long and short piles are made of cement-flyash-gravel (CFG) and lime. A new design calculation method of bearing capacity and settlement of composite foundation is introduced, and the calculated value is compared with the actual measurement. The results show that the liquefaction of soft ground is eliminated and the demand of load and settlement for upper building is met. At the same time, it is proved that the design method is feasible.

Bearing Capacity of a Group of Stone Columns in Soft Soil

2015 ◽  
Vol 15 (2) ◽  
pp. 04014043 ◽  
Author(s):  
M. Etezad ◽  
A. M. Hanna ◽  
T. Ayadat
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
Stone Columns ◽  
Group Of Stone Columns

scholarly journals Effect of Spacing between Stone Columns on the Behavior of Soft Soil

2021 ◽  
Vol 318 ◽  
pp. 01006
Author(s):  
Zeena A. Al-Kazzaz ◽  
Moataz A. Al-Obaydi
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
Soil Improvement ◽  
Stone Columns ◽  
The Finite Element Method ◽  
Slight Improvement ◽  
Short Columns ◽  
Sectional Shape ◽  
The Impact ◽  
Spacing Length

Soil improvement by stone columns is extensively used, especially for the soft ones. This is because of their efficiency and no environmental impact. Several factors affect its efficiency in improving the mechanical properties of the soil, and the most important of these factors are the spacing, length, and diameter of the stone columns. In this study, the finite element method was used to study the impact of the spacing between the stone columns on the amount of settlement and the bearing capacity of the soil. The study comprises three different spaces (s) that were taken in relation to the columns’ diameter (d), which are (s/d= 3, 4, and 5). In addition, three types of the sectional shape of column involved circular, rectangular, and square sections with different lengths of (L/d=2, 4, 6, 8, and 10). The results showed that the spacing between the stone columns is effective when the vertical load is greater than 30 kN/m2, and below this, there is no effect of the spacing. In general, the settlement decreases, and the bearing capacity increases with the decrease in the spacing between the stone columns. The spacing becomes a more pronounced effect with the longer length of the stone columns. All sections of the stone columns with a short length of (L/d=2) showed the same settlement of 271 mm at a distance (s/d=5), which decreases by 7.4, 6.6, and 8.9% at a distance (s/d=3) for the circular, rectangular and square sections respectively. In the case of long columns (L/d=10), the settlement at (s/d=3) improves by about 27.5% which drop to about 18% at (s/d=5). A slight improvement in the soil's bearing capacity is associated with decreases in the spacing between the stone columns. The improvements in the bearing of soil treated with short columns (L/d=2) are 6.0, 6.5, and 4.7% for circular, rectangular, and square sections, respectively, when changing the distance from (s/d=5) to (s/d=3). Whereas they become greater when increasing the columns’ length to (L/d=10) to be 7.9, 9.2, and 6.4%.

scholarly journals Numerical Analysis of Bearing Behavior of the Prebored Precast Pile with an Enlarged Base

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zao Ling ◽  
Jiangbin Wu ◽  
Weidong Wang
Keyword(s):  
Numerical Analysis ◽  
Bearing Capacity ◽  
Soft Soil ◽  
Expansion Ratio ◽  
Construction Technology ◽  
Analysis Model ◽  
Obvious Effect ◽  
Soil Thickness ◽  
Finite Element Software ◽  
Cement Soil

Prebored precast pile with an enlarged base (PPEB pile) is a new type of green and environmental protection pile foundation developed in China in recent years, which has complex bearing characteristics and many influencing factors. Based on the static load tests and key parameters’ tests in deep soft soil in Shanghai, a three-dimensional numerical analysis model was established using ABAQUS finite element software. The transfer law of load among the precast pile, cement soil, and soil around the pile and the action mechanism of the enlarged base were analyzed emphatically, and a sensitivity analysis of the main factors affecting the bearing performance was carried out. The calculation results show that the existence of the enlarged base can greatly improve the compressive bearing capacity, increasing the diameter and height of the enlarged base is beneficial to the bearing capacity, and the influence of the diameter expansion ratio is more effective. With the increase of the proportion of nodular piles, the ultimate bearing capacity increases slightly, but the deformation increases obviously. Under the condition of cement soil of the test piles, the spacing of the neighboring nodules of nodular piles has no obvious effect on the bearing capacity, and the 1 m spacing commonly used in engineering applications can be optimized. The increase of cement soil thickness is beneficial to the improvement of pile bearing capacity, but the efficiency is low. Finally, some improvement measures for the construction technology of the PPEB pile were put forward.

scholarly journals PENGARUH PERKUATAN TIANG TERHADAP STABILITAS TIMBUNAN DIATAS TANAH LUNAK MENGGUNAKAN METODE ELEMEN HINGGA

2020 ◽  
Vol 3 (2) ◽  
pp. 54
Author(s):  
Bambang Setiawan ◽  
Raden Harya Dananjaya H.I. ◽  
Muhammad Fathurrahman
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Safety Factor ◽  
Effective Stress ◽  
Soft Soil ◽  
Vertical Displacement ◽  
The Finite Element Method ◽  
The Road ◽  
Road Pavement

<p><em>Pile strength is widely used as a solution to the problem of road pavement on soft soil, because it can reduce vertical displacement due to the load on it and increase the safety factor value. This research analyses the vertical displacement, safety factor, effective stress and bearing capacity of the embankment on soft soil using the finite element method so the results can approach the original conditions in the field.</em> <em>The pile variations used are pile size variations 20x20 cm<sup>2</sup>; 25x25 cm<sup>2</sup>; and 30x30 cm<sup>2</sup> with a square shape, variations in the distance between the piles 1,60 m; 1,80 m; 2,00 m; and 2,20 m, the depth variations 15,00 m; and 20,00 m. Loading uses truck loads based on RSNI T-14-2004 and the road classification is artery IA. The results of the analysis show that pile strength with a size 20x20 cm<sup>2</sup>, the distance between pile is 1,60 m and the depth of the piles 20 m can reduce the vertical displacement by 71,31% and increase the safety factor by 123,25%.</em></p>

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