Yuichiro SHIMA

Study on the Needle Penetration Test of Foam Composite Light-weight Soil

Takaya KAINO

In the last year, Nitta and others proposed the needle penetration test, which can presume easily the unconfined compressive strength of Composite Light-weight Soil. In this study, some tests were performed for the purpose of improvement in the reliability of the needle penetration test and extending a scope of application. The followings are the main knowledge that obtained in this study.
(1) As the result of the test for consideration of the influence of the diameter of a needle on fluctuations of measured values, it turns out that a good result can be obtained in case of using the large diameter needle.
(2) The increase of penetration resistance after yielding of point resistance was thought to cause by skin friction, but the increase was caused by the compaction of the ground under tip of the needle.
(3) The unconfined compressive strength of the Light-weight Soil using clay with various combination, but can be described with the following formula.
qu=0.50P+75.4
qu: unconfined compressive strength [kPa]
P: yield value of point resistance [kPa]