• Geomechanics and Engineering
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• v.1 no.1
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• pp.75-84
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• 2009

Artificial neural networks (ANNs) are a new type of information processing system based on modeling the neural system of human brain. The prediction of swell pressures from easily determined soil properties, namely, initial dry density, initial water content, and plasticity index, have been investigated by using artificial neural networks. The results of the constant volume swell tests in oedometers, performed on statically compacted specimens of Bentonite-Kaolinite clay mixtures with varying soil properties, were trained in an ANNs program and the results were compared with the experimental values. It is observed that the experimental results coincided with ANNs results.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.2
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• pp.101-111
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• 2010

Characteristics of large-height swell-like waves that repeatedly occurred on the Korean East Coast in winter season were analyzed by using the wave observation data and the meteorological data. Based on the results of the data analysis, it was demonstrated that the swell-like waves have been generated due to the long-lasting strong northeasters in the East Sea, which were formed as a result of the low pressure trough in the vicinity of the extratropical low pressure system that advanced to East Sea from the China inland with decreasing its central pressure. Among the recently occurred events of the swell-like waves, the characteristics of the two events in October 2005 and 2006 were predominantly wind waves. Meanwhile, the one in February 2008 seems to be occurred by the initial wave growth due to wind waves followed by the secondly increase of the wave height due to longer-period swell.

• Geomechanics and Engineering
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• v.1 no.4
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• pp.307-321
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• 2009

The paper employs a feed forward neural network with back-propagation algorithm for modeling time dependent swell in clays containing carbonate in the presence of sulfuric acid. The oedometer swell percent is estimated at a nominal surcharge pressure of 6.25 kPa to develop 612 data sets for modeling. The input parameters used in the network include time, sulfuric acid concentration, carbonate percentage, and liquid limit. Among the total data sets, 280 (46%) were assigned to training, 175 (29%) for testing and the remaining 157 data sets (25%) were relegated to cross validation. The network was programmed to process this information and predict the percent swell at any time, knowing the variable involved. The study demonstrates that it is possible to develop a general BPNN model that can predict time dependent swell with relatively high accuracy with observed data ($R^2$=0.9986). The obtained results are also compared with generated non-linear regression model.

• Geomechanics and Engineering
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• v.19 no.1
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• pp.21-28
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• 2019

Use of cement in stabilizing the sulfate-bearing clay soils forms ettringite/ thaumasite in the presence of moisture leads to excessive swelling and causes damages to structures built on them. The development and use of non-traditional stabilisers such as alkali activated ground granulated blast-furnace slag (AGGBS) and enzyme for soil stabilisation is recommended because of its lower cost and the non detrimental effects on the environment. The objective of the study is to investigate the effectiveness of AGGBS and enzyme on improving the volume change properties of sulfate bearing soil as compared to ordinary Portland cement (OPC). The soil for present study has been collected from Tilda, Chhattisgarh, India and 5000 ppm of sodium sulfate has been added. Various dosages of the selected stabilizers have been used and the effect on plasticity index, differential swell index and swelling pressure has been evaluated. XRD, SEM and EDX were also done on the untreated and treated soil for identifying the mineralogical and microstructural changes. The tests results show that the AGGBS and enzyme treated soil reduces swelling and plasticity characteristics whereas OPC treated soil shows an increase in swelling behaviour. It is observed that the swell pressure of the OPC-treated sulfate bearing soil became 1.5 times higher than that of the OPC treated non-sulfate soil.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.209-212
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• 2007

Rubber compounds have high viscoelastic property. One of the viscoelastic behaviors during profile extrusion is the swelling of extrudate. In this study, die swell of rubber compounds at the capillary die have been investigated through an experiment and computer simulation. They have been performed using fluidity tester in experiment and commercial CFD code, Polyflow in computer simulation. Die swell of rubber compounds for relaxation time at several modes under same conditions with the experiment were predicted using non-linear differential viscoelastic model, Phan-Thien-Tanner (PTT) model. The simulation was analyzed compared with the experiment. Viscoelastic behaviors for pressure, velocity and shear rate distribution were analyzed at the capillary die. It is concluded that the PTT model successfully represented the amount of the optimal die swell of rubber compounds for relaxation time at different modes.

• Elastomers and Composites
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• v.22 no.3
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• pp.213-218
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• 1987

In this study, the rheological properties of a partially valcanized black filled EPDM were investigated as a function of degree of crosslinks using capillary rheometer. In order to obtain the samples having various degree of crosslinks between 0 and 6 percent, the vulcanization kinetics was also studied by Monsanto rheometer. The results showed that the die swell ana the pressure drop at the capillary entrance and exit increase nearly linearly with the increase in degree of crosslinks. However, melt fracture occurred at a lower shear rate for the samples of higher degree of crosslinks. These results were discussed in terms of the melt elasticity produced at the entrance region of capillary by the partial vulcanization. It is also interesting to note that the fluctuation of die swell during the practical extrusion or calendering process in the factories can be caused by the partial vulcanization occurred during the process.

• Geomechanics and Engineering
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• v.22 no.3
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• pp.227-236
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• 2020

Expansive soils are renowned for their swelling-shrinkage property and these volumetric changes resultantly cause huge damage to civil infrastructures. Likewise, subgrades consisting of expansive soils instigate serviceability failures in pavements across various regions of Pakistan and worldwide. This study presents the use of polypropylene fibers to improve the engineering properties of a local swelling soil. The moisture-density relationship, unconfined compressive strength (UCS) and elastic modulus (E₅₀), California bearing ratio (CBR) and one-dimensional consolidation behavior of the soil treated with 0, 0.2, 0.4, 0.6 and 0.8% fibers have been investigated in this study. It is found that the maximum dry density of reinforced soil slightly decreased by 2.8% due to replacement of heavier soil particles by light-weight fibers and the optimum moisture content remained almost unaffected due to non-absorbent nature of the fibers. A significant improvement has been observed in UCS (an increase of 279%), E₅₀ (an increase of 113.6%) and CBR value (an increase of 94.4% under unsoaked and an increase of 55.6% under soaked conditions) of the soil reinforced with 0.4% fibers, thereby providing a better quality subgrade for the construction of pavements on such soils. Free swell and swell pressure of the soil also significantly reduced (94.4% and 87.9%, respectively) with the addition of 0.8% fibers and eventually converting the medium swelling soil to a low swelling class. Similarly, the compression and rebound indices also reduced by 69.9% and 88%, respectively with fiber inclusion of 0.8%. From the experimental evaluations, it emerges that polypropylene fiber has great potential as a low cost and sustainable stabilizing material for widespread swelling soils.

• Geomechanics and Engineering
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• v.5 no.6
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• pp.565-574
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• 2013

Extensive study was carried out on Clay expansive soil. This soil was silty clay and can be classified as CH. The degree of expansion was found to range from low to medium depending on the free swell and swell pressure tests. The research investigated the effect of using cement dust on swelling potential, Atterberg Limit, linear shrinkage, and mineralogical composition of expansive soil. The results showed that the swelling potential, plasticity index, linear shrinkage, and clay minerals decrease with increasing cement dust percentage. The cement dust accumulates in huge amounts as a side product in cement factories, and the disposal of this fine dust is very difficult and poses an environmental threat.

• Elastomers and Composites
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• v.41 no.4
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• pp.223-230
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• 2006

Rubber compounds have a high viscoelastic property. One of the viscoelastic behaviors during profile extrusion is the swelling of extrudate, and the amount of swelling varies with operational conditions in extrusion. It is well recognized that the elastic portion in the viscoelastic property plays an important role in the extrudate swell. In this study computer simulation of the die swell at the capillary die for several rubber compounds has been performed using commercial CFD code, Polyflow. A non-linear differential viscoelastic model, Phan-Thien-Tanner (PTT) model, was used in the computer simulation. Non-isothermal behavior was considered in the calculation. Distribution of pressure, velocity and temperature in the reservoir and capillary die, and extrudate profiles were predicted through the simulation. The amount of the die swell fur the different rubber compounds was investigated for various flow rates and three types of length to diameter of the capillary die. It is concluded that the PTT model successfully represented viscoelastic behavior of rubber compounds.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.260-265
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• 2007

Rubber compounds have high viscoelastic property. One of the viscoelastic behaviors during profile extrusion is the swelling of extrudate. In this study, die swells of rubber compounds at the capillary die have been investigated through experiment and computer simulation. Experiments and simulations have been performed using fluidity tester and commercial CFD code, Polyflow respectively. Die swells of rubber compounds in a capillary die were predicted using non-linear differential viscoelastic model, Phan-Thien-Tanner(PTT) model for various relaxation times and relaxation modes. The results of simulation were compared with the experiments. Pressure and velocity distribution, and circulation flows at the comer of capillary die have been investigated through computer simulation. It is concluded that the PTT model successfully represented the amount of the die swell of rubber compounds for various relaxation times at different modes.