The undrained shear strength of the ground at a detached housing site can be estimated by the unconfined compressive strength, which is obtained from a core sample. However, this requires considerable time and money. Therefore, a formula, and experience, are usually applied to estimate the undrained shear strength. However, there is a problem with regard to reliability. In this case, a vane shear test is effective, but there can be a problem with the penetration ability. If we can identify a relationship between the results of a vane shear test and the results of Swedish sounding, we should be able to obtain accurate information about the ground very quickly from Swedish sounding. Therefore, we tested a method for estimating the undrained shear strength of soil from the torque value obtained by Swedish sounding. These results suggest that we can determine the undrained shear strength from the torque value in Swedish sounding.
Swedish weight sounding is a method for ground investigation that is a modification of weight sounding used in Sweden for use in Japanese ground. Swedish sounding was introduced in Japan in around 1930. Since then, it has commonly been applied as a soil survey technique in the field of civil engineering for the construction of the sub grade and base of pavements and port facilities (Fujii et al, 2003). This method also has a long history of application in the building construction field, mainly for the purpose of checking ground safety against contact pressure from heavy machinery, such as a crane (Inada, 1960). Swedish sounding was first used as a soil survey technique for the construction of small buildings in 1988 (AIJ, 1988). In Japan, that year also marked the beginning of a detached housing construction boom with an increased focus on the development of reclaimed lands.
