Shear Modulus Identification of Soft Bangkok Clay with Silica Powder using an Unconfined Compression Test with Bender Elements


  • Pithan Pairojn Civil Engineering Technology, Faculty of Science, Chandrakasem Rajabhat University


bangkok clay, bender element, shear modulus


The present study aimed to increase the undrained shear strength, elastic modulus and shear modulus of Bangkok Clay with silica powder when subjected to an unconfined compression test with bender elements. The shear wave velocity was measured using a pair of bender elements installed in the top cap and pedestal of the unconfined cell. The undrained shear strength measurement was conducted step by step in order to determine the variation of shear modulus. Measurement was carried out at the strain rate of 1%/min during which the shear modulus was continuously recorded. Results found that when the soil was mixed with silica powder at an increased rate, the undrained shear strength, elastic modulus, and shear modulus increased, whereas the strain decreased at the point of failure. It is concluded, therefore, that the improvement of soil quality using silica powder can lead to an increase in the efficiency of road construction.


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