International Session (Geotechnical Engineering)

[CS2-05] Effect of soil structure disturbance on the vertical stress degradation black volcanic ash soil under cyclic loading

〇OKRI ASFINO PUTRA¹, YASUFUKU Noriyuki¹, ISHIKURA Ryohei¹, ALOWAISY Adel¹, KAWAGUCHI Yuko² (1.Kyushu University, 2.NEXCO West)

Keywords:Soil structure, Vertical stress, Cyclic, Direct shear box

The soil structure disturbance effect due to the earthquake shakes on the vertical stress degradation was evaluated using a simple method that considers the pore size distribution that is reflected from the soil-water characteristic curve. In addition, the constant volume direct shear box considering cyclic tests was carried out. It was found that the undisturbed samples exhibit a unimodal pore structure, and the disturbed showed a bimodal pore. Since the pore structure of the disturbed sample is unstable, the degradation index value is higher than that of the undisturbed sample.