日本語フィールド
著者：Matsuo, Y., Usui, H., Hino, T. and Himeno, T.題名：Investigation on strength development characteristics of improved soil based on the relationship between consistency and shear strength発表情報：Proceeding of the 21st Southeast Asian Geotechnical Conference and 4th AGSSEA Conference (SEAGC-AGSSEA 2023)キーワード：Soft ground, Improved soil, Consistency, Fall cone tests概要：抄録：Our research group has been investigating the causes of quality deterioration in the heads of soil improved columns used in the deep mixing method in lowland areas of Saga Prefecture. The column heads are often located in the upper member of the Hasuike formation; thus, the quality deterioration has mainly been attributed to the abundance of organic substances due to the local sedimentary environment. In this study, fall cone tests were performed to analyze the strength development characteristics of cohesive soil of the Hasuike clay that was improved using cement slurry. The strength development characteristics were also examined based on the relationship between consistency and shear strength. The amount of cement-based binder mixed with the clay was 110 kg/m3 , and the water-cement ratio (W/C) was 0.5, 1.0, and 1.5. The mixture was stirred for 10 minutes using a soil mixer machine. Twelve cones were used to measure the consistency of the mixture at different times during the test. After each specimen was placed in the fall cone device, intrusion started due to the cone's weight, and the depth of intrusion was measured 5 seconds after the start. Measurements were taken every 10 minutes during the first 120 minutes after the end of mixing. The shift towards the plastic limit begins to accelerate 60 minutes after the end of mixing for the Hasuike clay. The peak values at 120 minutes after the end of mixing correspond to 'medium softness'. The change in consistency can be described as a change in state from 'very soft' to 'soft', and then to 'medium' in a short time. The changes in consistency and shear strength were more remarkable in improved soil with lower values of water-cement (W/C), and vice versa.英語フィールド
Author：Matsuo, Y., Usui, H., Hino, T. and Himeno, T.Title：Investigation on strength development characteristics of improved soil based on the relationship between consistency and shear strengthAnnouncement information:Proceeding of the 21st Southeast Asian Geotechnical Conference and 4th AGSSEA Conference (SEAGC-AGSSEA 2023)Keyword：Soft ground, Improved soil, Consistency, Fall cone testsAn abstract：Our research group has been investigating the causes of quality deterioration in the heads of soil improved columns used in the deep mixing method in lowland areas of Saga Prefecture. The column heads are often located in the upper member of the Hasuike formation; thus, the quality deterioration has mainly been attributed to the abundance of organic substances due to the local sedimentary environment. In this study, fall cone tests were performed to analyze the strength development characteristics of cohesive soil of the Hasuike clay that was improved using cement slurry. The strength development characteristics were also examined based on the relationship between consistency and shear strength. The amount of cement-based binder mixed with the clay was 110 kg/m3 , and the water-cement ratio (W/C) was 0.5, 1.0, and 1.5. The mixture was stirred for 10 minutes using a soil mixer machine. Twelve cones were used to measure the consistency of the mixture at different times during the test. After each specimen was placed in the fall cone device, intrusion started due to the cone's weight, and the depth of intrusion was measured 5 seconds after the start. Measurements were taken every 10 minutes during the first 120 minutes after the end of mixing. The shift towards the plastic limit begins to accelerate 60 minutes after the end of mixing for the Hasuike clay. The peak values at 120 minutes after the end of mixing correspond to 'medium softness'. The change in consistency can be described as a change in state from 'very soft' to 'soft', and then to 'medium' in a short time. The changes in consistency and shear strength were more remarkable in improved soil with lower values of water-cement (W/C), and vice versa.