Article Per Year (5 Year)
p-Index From 2021 - 2026
0.23
P-Index
This Author published in this journals
All Journal Lowland Technology International
Ryohei Ishikura
Geotechnical Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, Kyushu University
Civil Engineering, Building, Construction & Architecture Engineering Transportation

Published : 2 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 2 Documents
Search

 1 
Shear strength characteristic of unsaturated undisturbed black volcanic ash soil in Kumamoto under static and cyclic loading Okri Asfino Putra; Noriyuki Yasufuku; Adel Alowaisy; Ryohei Ishikura; Ahmad Rifa'i; Yuko Kawaguchi
Lowland Technology International Vol 22 No 2 (2020): Lowland Technology International Journal
Publisher : International Association of Lowland Technology

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.0001/ialt_lti.v22i2, Septemb.707

Abstract

Black volcanic ash soil which is also known as Kuro-boku soil in Japan is a problematic type of soil. Kuro-boku is usually rich with allophane minerals, which are characterized by unique problematic properties. Through this paper, the shear strength and characteristics of the black volcanic ash soil collected at Kumamoto slope failure after earthquake 2016 were studied using three main approaches. The chemical composition of the black volcanic ash soil was investigated using the X-ray fluorescence analysis. Furthermore, the soil structure disturbance effect due to the earthquake shakes on the total shear strength 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 static and cyclic tests were carried out. It was found that the main chemical content of the black volcanic ash soil is allophane which accounts for about 94 %. Furthermore, 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 static shear strength tends to be lower and the degradation index value is higher than that of the undisturbed sample.
Evaluation of Elastic Settlement Behavior in Small-Strain Range of Cement-Treated Clayey Soil Muhammad Akmal Putera; Noriyuki Yasufuku; Adel Alowaisy; Ryohei Ishikura; Jumana G. Hussary; Ahmad Rifa’i
Lowland Technology International Vol 24 No 2 (2022): Lowland Technology International Journal
Publisher : International Association of Lowland Technology

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.0001/ialt_lti.v24i2.1440

Abstract

Indonesia is developing high-speed railway lines that are expected to connect the major cities. Along the railway, the lowland area is mainly comprised of clayey soil characterized by a high compressibility index and high water content, which causes soil settlement in the long term. Therefore, to reduce the potential of settlement, choosing a suitable railway structure, such as the ballastless track, is essential. Despite the track structure, the subsoil mechanical properties often require improvement to limit the railways’ settlement. Using cement-treated soil, a combination technique was provided to protect the shallow ground and the ballastless track, effectively reducing the stress distribution during construction periods and maintaining low construction costs for developing countries. To assure longer serviceability, there is a high need for an accurate evaluation of the elastic settlement subjected to train loading. Therefore, this paper proposes an elastic settlement prediction model for cement-treated soils considering the curing period, cement content, and confining pressure within the small-strain ranges. The model optimizes the mixing ratio at a specific curing period, reflecting the wheel-base loading on the cement-treated soil layer. Moreover, a simple power formula to determine the initial mechanical properties of the cement-treated soils was proposed.
Co-Authors Adel Alowaisy Ahmad Rifa'i Ahmad Rifa’i Jumana G. Hussary Muhammad Akmal Putera Noriyuki Yasufuku Okri Asfino Putra Yuko Kawaguchi