In the ground survey for detached houses in Japan, the Swedish weight sounding test (hereinafter referred to as SWS test) is most widely used. However, they have not been estimated the liquefaction resistance of the ground by means of the SWS test directly because the relation between the liquefaction resistance of the ground and the Nsw value of SWS test has not been clarified. Hence, the authors examined the relationship between the liquefaction resistance of the ground by triaxial test and the Nsw value of SWS test using the model ground. As a result, a unique relationship between Nsw and liquefaction resistance was found for sand without fine content, and it was shown that the liquefaction resistance of the ground could be estimated from Nsw.
During The Great East Japan Earthquake in 2011, large liquefaction occurred along the Tokyo Bay coastal area. Damage to the structure by the liquefaction concentrated on detached houses. Currently in Japan, the possibility of liquefaction of sandy grounds is evaluated from the N- value of the standard penetration test and the soil test result of tested soils. While in the construction of detached houses, it is rare that a standard penetration test, with a high ground investigation cost, is executed compared to the upper structure. In Japan, the SWS test is widely adopted for ground survey of the residential area because of easy operation and excellent cost effectiveness. The penetration resistance value (Wsw, Nsw) of the SWS test is mainly used for evaluating the ground bearing capacity of the residential land. When evaluating the liquefaction resistance from the SWS test results, it is possible to evaluate by converting the NSW value to the N-value, while questions remain in the accuracy of the converted value. Considering the liquefaction damage of the detached houses in recent years, it is of great significance to search for a direct relationship between penetration resistance of SWS test and liquefaction resistance of the same position.