Geotechnical Properties of Diatom soft Rock and Stability Analysis of Cut Slope

1994 Fiscal Year Final Research Report Summary

• Project/Area Number: 04452229
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 基礎・土質工学
• Research Institution: Saga University
• Principal Investigator: ONITSUKA Katsutada Saga University, professor, 理工学部, 教授 (20037948)
• Co-Investigator(Kenkyū-buntansha): YOSHITAKE Shigeki Saga University, Research. Assist., 理工学部, 助手 (00145187) ; SAKAI Akira Saga University, Assoc. Professor, 理工学部, 助教授 (00162256)
• Project Period (FY): 1992 – 1994
• Keywords: diatom earth / cut slope / cementation / slaking / strength anisotropy / tensile strength / stabiliation

Research Abstract

Part 1 describes that the Diatom earth in Oita prefecture has been an object of subbase of new free way and cut slope. The Diatom earth particle is porous material and water content is very high such as Ariake clay. Cementation effect is very strong, however slaking phenomenon is remarkable by drying and wetting. This part 1 concludes that physical and chemical properties and mechanical properties, stability of cut slope, utilization of Diatom earth by stabilization are important subjects in this research.
Part 2 describes the distribution of deposition in Japan and Oita prefecture. Part 3 shows physical and chemical properties, and compared above properties with that of some problematic soils in Kyusyu.
Some kinds of laboratory tests were performed in Part 4, and effects of repetition of drying and wetting on mechanical properties were investigated in Part 5. The decrease in compressive strength is greater than that in tensile strength. Using these test results, some finite element analyzes were carried out for the slope in Part 6. The slope failure will occur due to the decreasing in tensile strength in the worst case. Part 7 describes the stabilization by quick lime and cement, and mechanical properties of stabilized diatom earth.