Mechanical behaviour of unsaturated undisturbed black volcanic ash soil under static and cyclic loading

Okri Asfino Putra, Noriyuki Yasufuku, Ryohei Ishikura, Adel Alowaisy, Yuko Kawaguchi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The mechanical behaviour of unsaturated undisturbed black volcanic ash soils was investigated using a constant volume direct shear apparatus. A series of static and cyclic tests were conducted under unsaturated and saturated samples. The cyclic test under two patterns were adopted. First type of pattern, cyclic one-sided shearing was applied. For the second type, two-sided shearing was conducted. For further understanding of the chemical content and microstructure, X-Ray Fluorescence analysis (XRF) and Scanning Electron Microscope (SEM) were evaluated. It was found that, under static shearing, the unsaturated sample exhibits a higher apparent cohesion and friction angle in comparison to the saturated sample. The normalized vertical stress under one-sided cyclic shearing in both overconsolidated and normally consolidated samples rapidly reduced at the beginning of shearing. This might be attributed to increase of the pore water pressure during shearing. Furthermore, there is a significant difference between the normalized shear stress under cyclic one-sided and two-sided shearing. For the two-sided cyclic shearing test, the normalized shear stress value is higher than the one-sided cyclic shearing test. In addition, the normalized shear stress under unsaturated condition is significantly larger. This can be related to the suction forces to the total strength of soils. The main chemical content of the black volcanic ash soil is allophane. Further, the microstructure of the black volcanic ash changes due to shearing. For the overconsolidated sample, particles of soil more severe damage than normally consolidated sample.

Original languageEnglish
Title of host publication7th International Symposium on Deformation Characteristics of Geomaterials, IS-Glasgow 2019
EditorsErdin Ibraim, Alessandro Tarantino
PublisherEDP Sciences
ISBN (Electronic)9782759890644
DOIs
Publication statusPublished - Jun 25 2019
Event7th International Symposium on Deformation Characteristics of Geomaterials, IS-Glasgow 2019 - Glasgow, United Kingdom
Duration: Jun 26 2019Jun 28 2019

Publication series

NameE3S Web of Conferences
Volume92
ISSN (Print)2555-0403
ISSN (Electronic)2267-1242

Conference

Conference7th International Symposium on Deformation Characteristics of Geomaterials, IS-Glasgow 2019
CountryUnited Kingdom
CityGlasgow
Period6/26/196/28/19

All Science Journal Classification (ASJC) codes

  • Environmental Science(all)
  • Energy(all)
  • Earth and Planetary Sciences(all)

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  • Cite this

    Putra, O. A., Yasufuku, N., Ishikura, R., Alowaisy, A., & Kawaguchi, Y. (2019). Mechanical behaviour of unsaturated undisturbed black volcanic ash soil under static and cyclic loading. In E. Ibraim, & A. Tarantino (Eds.), 7th International Symposium on Deformation Characteristics of Geomaterials, IS-Glasgow 2019 [07004] (E3S Web of Conferences; Vol. 92). EDP Sciences. https://doi.org/10.1051/e3sconf/20199207004