Bearing Capacity of a Group of Stone Columns in Soft Soil Subjected to Local or Punching Shear Failures

2018 ◽  
Vol 18 (12) ◽  
pp. 04018169 ◽  
Author(s):  
M. Etezad ◽  
A. M. Hanna ◽  
M. Khalifa
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
Punching Shear ◽  
Stone Columns ◽  
Group Of Stone Columns ◽  
Shear Failures

Bearing Capacity of Group of Stone Columns with Granular Blankets

2017 ◽  
Vol 17 (2) ◽  
pp. 253-263 ◽  
Author(s):  
Javad Nazariafshar ◽  
Nima Mehrannia ◽  
Farzin Kalantary ◽  
Navid Ganjian
Keyword(s):  
Bearing Capacity ◽  
Stone Columns ◽  
Group Of Stone Columns

scholarly journals Estimation of bearing capacity of floating group of stone columns

2017 ◽  
Vol 20 (3) ◽  
pp. 1166-1172 ◽  
Author(s):  
Mohammed Y. Fattah ◽  
Mohammed A. Al-Neami ◽  
Ahmed Shamel Al-Suhaily
Keyword(s):  
Bearing Capacity ◽  
Stone Columns ◽  
Group Of Stone 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.

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.

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 Evaluation Of Use of Stone Column in Unengineered Closed Landfill Soil

2021 ◽  
Vol 23 (08) ◽  
pp. 538-548
Author(s):  
Mandeep Singh ◽  
◽  
Dr Prashant Garg ◽  
Keyword(s):  
Bearing Capacity ◽  
Load Capacity ◽  
Ground Improvement ◽  
Soft Soil ◽  
Confining Pressure ◽  
Lateral Spreading ◽  
Silty Sand ◽  
Stone Columns ◽  
Stone Column ◽  
Closed Landfill

In the building industry, ground improvement techniques based on stone column are widely employed. It is a very successful approach for enhancing the engineering characteristics of soil in all aspects, as well as reducing the settling issue in poor-grounded soils including silt, clay, silty sand, and organic soil. The performance of stone columns, is determined by the confining pressure provided by the surrounding soils. Engineering constructions built on thick layers of soft soil strata face issues such as limited bearing capacity, excessive total and differential settlement, lateral spreading, and so on. To address such issues, many ground improvement techniques are available. In exceptionally soft soils, the lateral confining pressure may be inadequate, resulting in column bulging failure. Individual stone column encasement improves lateral resistance to bulging by adding restricting pressure. This research focuses on the geotechnical aspects of building on closed landfill sites. A total of 33 models were tested in a geotechnical engineering laboratory on virgin former landfill soil and stone column with and without encasement in this current study. The increased diameter, length and L/D ratio of the column has demonstrated that the load capacity has increased and soil settling has decreased. When an unreinforced stone column has been installed, the ultimate bearing capacity of landfill soil is increased by 75-112.50 per cent and 87.50-176 per cent respectively, for 10mm and 20mm diameter stone column. Furthermore, when a fully reinforced stone column has been installed, it had increased by 156.25-212.50 per cent and 200-298 per cent for 10mm and 20mm diameters respectively. The stiffness of soil is increased by the stone column, which contributes to increase in the load capacity. The geogrid layer confines an aggregate, which contribute to enhance shear stiffness and bearing capacity.

scholarly journals Improvement of Soft Soil Using Linear Distributed Floating Stone Columns under Foundation Subjected to Static and Cyclic Loading

2019 ◽  
Vol 5 (3) ◽  
pp. 702 ◽  
Author(s):  
Mahdi O Karkush ◽  
Anwar Jabbar
Keyword(s):  
Cyclic Loading ◽  
Bearing Capacity ◽  
Soft Soil ◽  
Friction Angle ◽  
Soil Improvement ◽  
Stone Columns ◽  
Stone Column ◽  
Column Material ◽  
Area Replacement Ratio ◽  
Static And Cyclic Loading

A stone column is one of the soil improvement methods that are mainly used for improving the geotechnical behavior of soft soils. For deep improvement of soft soil, the floating stone columns are considered the best and effective economically which provide lateral confinement and drainage and longitudinal skin friction. In this study, six tests were carried out on the natural soft soil of undrained shear strength of 5.5 kPa improved by single and two linear distributed floating stone columns. The stone column dimensions are 30 mm in diameter and 180 mm in length and the stone column material is sand of high internal friction angle of 48°. The natural and improved soil samples are tested under isolated raft foundation of dimensions 120×120 mm subjected to vertical static and cyclic loading of frequency 2Hz and continued for 50 seconds. The results showed a significant improvement in soil bearing capacity when reinforced with stone columns despite the small area replacement ratio, where the bearing capacity of improved soil increased by 120 to 145%. The compressibility of improved soil decreased by 57 to 86% in comparison with that of natural soft soil. Also, the floating stone columns reduced the porewater pressure, where the stone columns considered efficient in providing short drainage pathways. This can be one of the reasons why soil reinforced with floating stone columns hold higher cyclic and static stresses regardless the end bearing of stone columns.

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