Physical Modeling of Stone Columns in Unsaturated Soil Deposits

The improvement of weak or loose soil deposits by the vibrational technique has now become a well established method. Loose or medium dense sands can be compacted with slender, cylindrical vibrators (vibro-compaction method). Cohesive or organic soil can be improved by their partial displacement or replacement with selected granular material which is vibrated into the parent soil (vibro-replacement method). Compaction depth up to 30 m (100 ft) can be achieved.This paper describes the method of construction of compaction columns and stone columns. Method of estimating the settlement of the improved soil under given load conditions is presented. The applicability and limits of the process are outlined.Two case histories are discussed and they were chosen for their various degrees of difficulties encountered in the subsoil and because the settlement specifications placed very strict limits on the foundation performance.

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The Effect of Soil–Cement Barriers in Containing the LNAPL Contaminants Transport in Unsaturated Soil: A Physical Modeling

Soil and Sediment Contamination An International Journal ◽

10.1080/15320383.2021.2000364 ◽

2021 ◽

pp. 1-23

Author(s):

Ali Behdad ◽

Majid Moradi ◽

Amirhossein Afshari Aghajari

Keyword(s):

Unsaturated Soil ◽

Physical Modeling ◽

Soil Cement ◽

Contaminants Transport

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Field performance of the port of Sepetiba test fills

Canadian Geotechnical Journal ◽

10.1139/t95-008 ◽

1995 ◽

Vol 32 (1) ◽

pp. 106-121 ◽

Cited By ~ 2

Author(s):

Vinod K. Garga ◽

Luciano V. Medeiros

Keyword(s):

Ground Improvement ◽

Soft Soil ◽

Soft Clay ◽

Field Performance ◽

Stone Columns ◽

Field Investigations ◽

Large Program ◽

Soil Deposits ◽

Load Tests ◽

The Cost

The design of the industrial port of Sepetiba, 50 km south of Rio de Janeiro, Brazil, required a detailed evaluation of the underlying soft soil deposits. Initially, on the basis of laboratory tests, it was proposed to remove approximately 3.7 × 106 m3 of the very soft deposits in the stockpile area by dredging and substitute with hydraulic sand fill. Subsequently, in view of the cost of such a measure, a large program of field investigations was initiated to study the in situ characteristics of the soft clay to evaluate whether replacement of this material and (or) ground improvement was necessary. As part of this investigation, two large identically instrumented test fills (test fills B and D), each 65 m2 in plan and 5 m high, with 3:1 slopes were constructed. Test fill B was constructed over natural ground, whereas the subsoil beneath test fill D was treated with stone columns. The instrumentation for each test fill consisted of piezometers, deep settlement plates, surface settlement plates, and inclinometers. This paper provides a description of the field investigations, observations on installation of stone columns, analysis of instrumentation, a comparison of the behaviour of the two test fills, and a discussion on load tests on individual stone columns. Key words : case history, embankment, ground improvement, instrumentation, soft clay, stone columns.

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

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/961/1/012052 ◽

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.

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