Observation of boiled sand erupted from liquefied layer

Abstract

A trench excavation was conducted at Itako City, Ibaraki prefecture, to observe the trace of boiled sand which elevated along cracks in the silt layer, due to liquefaction at Great East Japan Earthquake. Undisturbed soil samples were taken from the sand and silt layers of about 2 to 3 m deep. X ray CT scanning was conducted for the undisturbed specimens to observe the micro structure of liquefied soil. The image obtained from X ray CT indicated the path of boiled sand erupted from liquefied sand layer. The overall structure of liquefied layer is mostly disturbed in contrast with laminar structures observed in a non-liquefied layer.