• Geotechnical Engineering
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• v.12 no.6
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• pp.51-64
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• 1996

After the model open-ended pile attached with strain gages was driven into a pressure chamber, in which the saturated microfine sand was contained, the static compression loading test was performed for that pile. Based on the test results, ultimate pile capacity was determined. Then, either simulated earthquake shaking or sinusoidal shaking was applied to the pile with the sustained certain level OP ultimate pile load. Then, pile capacity degradations characteristics during shaking were studied. Pile capacity degradation during two different shakings were greatly different. During the simulated earthquake shaking, capacity degradation depended upon the magnitude of applied load. When the load applied to the pile top was less than 70% of ultimate pile capacidy, pile capacity degradation rate was less than 8%, and pile with the sustained ultimate pile load had the degradation rate of 90%. Also, most of pile capacity degradation was reduced in outer skin friction and degradation rate was about 80% of ultimate pile capacity reduction. During sinusoidal shaking, pile capacity degradation did not depend on the magnitude of applied load. It depended on the amplitude and the frequency , the larger the amplitude and the fewer the frequency was, the higher the degradation rate was. Reduction pattern of unit soil plugging (once depended on the mode of shaking. Unit soil plugging force by the simulated earthquake shaking was reduced in the bottom 3.0 D, of the toe irrespective of the applied load, while reduction of unit soil plugging force by sinusoidal shaking was occurred in the bottom 1.0-3.0D, of the toe. Also, the soil plugging force was reduced more than that during simulated earthquake shaking and degradation rate of the pile capacity depended on the magnitude of the applied load.

• Geotechnical Engineering
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• v.12 no.2
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• pp.19-32
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• 1996

Based on Trifuilac's empirical model to transform earthquake acceleration time history in the time domain into Fourier amplitude spectrum in the frequency domail an earthquake scaling technique for simulating the earthquake record of certain magnitude as the required magnitude earthquake was suggested. Also, using the earthquake record of magni dude(M) 5.8, the simulated earthquake of magnitude(M) 8.0 was established and its application to dynamic testing system was proposed. The earthquake scaling technique could be considered by several terms : earthquake magnitude(M), earthquake intensity(MMI), epicentral distance, recording site conditions, component direction and confidence level required by the analysis. Albo, it had an application to the various earthquake records. The simulated earthquake in this study was established by two orthogonal horizontal components of earthquake acceleration-time history. The simulated earthquake shaking could be applied to the dynamic pile load test for the model tension pile and the model compressive open -ended piles driven into the pressure chamber. In the static pile load test, behavior of two piles was very different and after model tension pile experienced 2 or 3 successive slips of the pile relative to the soil, it was failed completely. During the simulated earthquake shaking, dynamic behavior and pile capacity degradation of two piles were very different.

• Geomechanics and Engineering
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• v.12 no.3
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• pp.523-539
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• 2017

Clay soils are typical for their swelling properties upon absorption of water during rains and development of cracks during summer time owing to the profile desorption of water through the inter-connected soil pores by water vapour diffusion leading to evaporation. This type of unstable soil phenomenon by and large poses a serious threat to the strength and stability of structures when rest on such type of soils. Even as lime and cement are extensively used for stabilization of clay soils it has become imperative to find relatively cheaper alternative materials to bring out the desired properties within the clay soil domain. In the present era of catastrophic environmental degradation as a side effect to modernized manufacturing processes, industrialization and urbanization the creative idea would be treating the waste products in a beneficial way for reuse and recycling. Bottom ash and ecosand are construed as a waste product from cement industry. An optimal combination of bottom ash-eco sand can be thought of as a viable alternative to stabilize the clay soils by means of an effective dispersion dynamics associated with the inter connected network of pore spaces. A CATIA model was created and imported to ANSYS Fluent to study the dispersion dynamics. Ion migration from the bottom ash-ecosand pile was facilitated through natural formation of cracks in clay soil subjected to atmospheric conditions. Treated samples collected at different curing days from inner and outer zones at different depths were tested for, plasticity index, Unconfined Compressive Strength (UCS), free swell index, water content, Cation Exchange Capacity (CEC), pH and ion concentration to show the effectiveness of the method in improving the clay soil.