Self-Adjusted Pneumatic Loading Oedometer for 1D Consolidation

Wuttinan Pratooma andSiriporn Tangwiboonpanichb

Faculty of Industrial Technology, SakonnakhonRajabhat University, Thailand

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Manuscript received July 20, 2015

Revised August 17, 2015

Abstract

This research aimed to develop an automatic Oedometer which was soil testing equipment. The traditional equipment requires an operator to manually place loads and read values of a vertical displacement. The traditional Oedometer was improved in two parts namely self-adjusted loading and automatically record vertical displacement value. The applied load of the developed equipment was generated from pressure that was supplied by a pneumatic system. The pressure of an air-compressor was controlled by the electro-pneumatic regulator and changed to load via air-cylinder equipment. The load cell transducer was used to measure the applied load value of the developed equipment. The vertical displacement of soil sample was measured by linear variable displacement transformer (LVDT) transducer. This developed equipment was controlled by a particular software application that was written in Visual Basic computer program language. The controlling program was used to adjust the value of applied load and to record the vertical displacement value of soil sample. The recording value was saved in a text file which was convenient to import into MS Excel for further analysis. To verify the accuracy of the developed equipment, the researchers conduct 1D consolidation test for both the developed and the traditionalOedometer. The verification procedure began from loaded soil sample by the traditionalOedometer until the applied stress more than pre-consolidation pressure then the soil sample was unloaded. Next, the same soil specimen was reloaded by the automatic Oedometer until the end of the testing stage. Finally, the obtained results were used to draw the consolidation graph for comparing the settlement values between the traditional and the modified equipment. The findings showed that the vertical displacement that was obtained from the developed apparatus was in excellent agreement with those obtained from the original one. However, this developed equipment was not a completed automatic-equipment because it still needed an operator to fill water of the soil sample.

Keyword: 1D Oedometer; Consolidation; Automatic

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