Effects of Electro Osmotic Consolidation in South West of Johor: Small Laboratory Scale

2014 ◽  
Vol 803 ◽  
pp. 255-264
Author(s):  
Khairul Nizar Mohd Yusof ◽  
Fauziah Ahmad ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Muhammad Faheem Mohd Tahir
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Clay Soil ◽  
Soft Clay ◽  
Soil Improvement ◽  
Undrained Shear Strength ◽  
Engineering Structures ◽  
Vertical Loading ◽  
South West ◽  
Undrained Shear

Clay soil is one of the problematic soils due to its natural states which have low bearing capacity and high compressibility. The effect and problem of the clay soil characteristic creates a problem for construction especially excessive settlement and this can lead to unstable and potential cracks of engineering structures. At presents, there are few of soil improvement types can be carried out to overcome these problems, and electro osmotic consolidation is one of the options. This method has been applied many years ago especially in european countries. The study encompasses the determination of water content, atterberg’s limits and undrained shear strength after electro osmotic consolidation treatment of clay soils taken from 0.5 m and 1.5 m at southwest part of johor. All the samples were tested according to BS1377:1990. An experimental study was implemented in a pvc cylinder tube having dimensions of 300 mm height and 100 mm diameter. In the results of electro osmotic consolidation tests by installing copper spring electrodes, the measured undrained shear strength was increased considerably at the anodes especially compared to the initial undrained shear strength due to electro osmosis process and consolidation. As laboratory studies of its measurement have shown, the application of electro osmotic consolidation after the application of a direct current applied voltage of 10 volts, at the anodes especially: (i) a decrease by approximately 35% in water content; (ii) an increase around 29% in undrained shear strength; and (iii) a decrease about 21% in index plasticity. The results obtained in this study shows that the electro osmotic enhanced 15 kpa vertical loading consolidation is a feasible approach in strengthening of south west soft clay in johor. It can be clearly suggested that the higher the voltage applied in the system, the higher readings of undrained shear strength and the lower of water content especially at the anodes.

Determination of the consistency limits of soils by the fall cone test

1986 ◽  
Vol 23 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Y. Wasti ◽  
M. H. Bezirci
Keyword(s):  
Shear Strength ◽  
Key Words ◽  
Water Content ◽  
Strength Criterion ◽  
Undrained Shear Strength ◽  
Wide Range ◽  
Undrained Strength ◽  
Content Range ◽  
Undrained Shear

The liquid and plastic limits for a variety of natural and artificial soils covering a wide range of plasticity, as determined by the Casagrande method and the fall cone test and based on a strength criterion, were compared. To check the validity of the strength criterion, the undrained shear strength of these soils has been determined with a laboratory vane over the water content range between these limits. A limited comparison of the undrained strength values obtained from the vane test and fall cone test is also given. Key words: Atterberg limits, consistency, fall cone, laboratory vane, shear strength.

Uplift tests on full-scale pipe segment in lumpy soft clay backfill

2016 ◽  
Vol 53 (4) ◽  
pp. 578-588 ◽  
Author(s):  
R.P. Chen ◽  
B. Zhu ◽  
W.J. Ni
Keyword(s):  
Shear Strength ◽  
Soft Clay ◽  
Vertical Displacement ◽  
Undrained Shear Strength ◽  
Full Scale ◽  
Scale Model ◽  
Pressure Transducers ◽  
Pipe Segment ◽  
Clay Ground ◽  
Undrained Shear

Upheaval buckling of pipelines caused by thermal- and pressure-induced loading is an important issue in pipeline design. The uplift capacity of pipelines is determined by the pipe–soil interaction during pipeline upheaval in soil. Pipelines to be installed in soft clay are usually placed into trenches and then backfilled. In this paper, a set of test devices were developed and a series of full-scale model tests were carried out on a pipe segment buried in lumpy soft clay backfill, including backfilling tests, load-controlled uplift tests, and a displacement-controlled test. Eight total pressure transducers were embedded in the wall of the pipe segment to measure soil pressures on the pipe segment, and five linear variable differential displacement transducers (LVDTs) were arranged to record the vertical displacement of the pipe segment and the surface of the soft clay ground. The stabilizing force keeping the pipe segment in place during the backfilling process was found to fit a nearly linear relationship with the dimensionless undrained shear strength of soft clay. The variation of soil pressures on the pipe segment during uplift loading was significantly affected by the buried depth of the pipe segment and the undrained shear strength of the soil. For all present load-controlled tests in lumpy soft clay backfill, the test ultimate uplift resistances were only about 19%–81% of the results calculated by the Det Norske Veritas approach. Mainly due to the voids’ compression, shearing and strain softening of lumpy soft clay backfill, the difference between initial and stable displacements in a loading step for a load-controlled test or initial and stable loads in a displacement step for a displacement-controlled test is remarkable. The limits of uplift resistances are recommended for the instant and sustaining behaviors of the pipe segment, respectively.

scholarly journals Some Geotechnical Properties of Plastic Soil Enhanced with Cement Dust

2021 ◽  
Vol 27 (10) ◽  
pp. 20-33
Author(s):  
Abeer F. Hussein ◽  
Ahmed S. Ali ◽  
Abbas J. Al-Taie
Keyword(s):  
Shear Strength ◽  
Dry Weight ◽  
Undrained Shear Strength ◽  
Geotechnical Properties ◽  
Cement Kiln ◽  
Compression Tests ◽  
Cement Dust ◽  
Engineering Structures ◽  
Soil Cement ◽  
Undrained Shear

Plastic soil exhibits unfavorited geotechnical properties (when saturation), which causes negative defects to engineering structures. Different attempts (included various materials) were conducted to proffer solutions to such defects by experimenting in practical ways. On one hand, these attempts aimed to improve the engineering characteristics of plastic soil, and on the other hand, to use problematic waste materials as a stabilizer, like cement kiln dust, and to reduce environmental hazards. This paper explored the shrinkage, plasticity, and strength behavior of plastic soil enhanced with cement dust. The cement dust contents were 0%, 5%, 10%, 15% and 20% by dry weight of soil. An experimental series of shrinkage and plasticity tests and unconfined compression tests were carried out to explore the effects of cement dust on the quantitative amount of shrinkage, plasticity characteristics, and shear strength experienced by plastic soil. The effects of curing on soil strength were also investigated. The finding of this paper showed that the critical behavior and plasticity of plastic soil could be reduced by mixing the soil with 15% or 20% of cement dust. The undrained shear strength, cu, of plastic soil-cement dust mixtures increased with the increasing dust content up to 20%. In fact, this strength was affected by the curing period. The best enhancement was attained when the content of cement dust was 20%, and the undrained shear strength was increased more than three times at this content.

Effect of sand percentage on the compaction properties and undrained shear strength of low plasticity soft clay

2021 ◽  
Author(s):  
Iyad Alkroosh ◽  
◽  
Ali Al-Robay ◽  
Prabir Sarker ◽  
Saif Alzabeebee ◽  
...  
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Soft Clay ◽  
Undrained Shear Strength ◽  
Optimum Moisture Content ◽  
Dry Density ◽  
Sand Content ◽  
Compression Tests ◽  
Maximum Dry Density ◽  
Undrained Shear

This study investigated the influence of sand content on the mechanical behaviour of a low plasticity clay found in Iraq. Samples were prepared with sand contents of 0%, 10%, 20%, 30%, and 40% of the weight of the clay. Standard Proctor and unconfined compression tests were carried out and the optimum moisture content, maximum dry density, and undrained shear strength were determined. The results showed a gradual increasing trend of the maximum dry density with the increase of the sand content up to 30%. The highest dry density reached was 1.90 gm/cm3 corresponding to an optimum moisture content of 12%. In addition, it was also found that the undrained shear strength was inversely proportional to the increase of the percentage of sand. Thus, the dry density of the clay could be increased well above 1.70 g/cm3, which is the minimum dry density accepted as a compacted subgrade according to the Iraqi General Specifications for Roads and Bridges (2003); hence, the rejected low plasticity clay could be utilised by mixing with sand. The reasons for the increase of the dry density and the decrease of the undrained shear strength has been extensively discussed in the paper.

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