Dry sand was compacted by vibration in horizontal direction. A vibrating plate was set vertically at one end of a box, and the plate was excited by a vibrator. Settlement of sand and vibration within sand were measured.Followings were obtained by the experiments.1) The ratio of settlement at certain elapsed time to the settlement at 8 minutes (called "settlement ratio") for constant frequency was constant regardless of the horizontal distance and the value of frequency.2) Vibrating plate showed a characteristic of resonance, but it was not considered to be in full contact with the sand at higher frequencies than 1, 500 rpm. And the resonance frequency did not change when a shorter box was used.3) Settlement-frequency relation could be divided into two parts, one was the range below the resonance and the other was over 1, 500 rpm. In practical problems, the latter range of frequency has been used and considered to be effective.4) Higher harmonics in the wave may play an important role in compaction of dry sand.5) The vibrator elements which govern the settlement of sand in the range from about 1, 500 rpm to 1, 800 rpm were considered to be the product of eccentric moment and angular velocity.

View full abstract

Hachiro-Gata Impoldering Project is one of the greatest impoldering works which have been performed in Japan. The major part of the lagoon bottom is covered with deep and very soft clay deposits and some parts of the polder dikes are compelled to be built on these bad subsoils. Two types of test dikes, that is replacement type and sand-bed type, were built to examine the calculated results of dike design before the construction of dikes.The authors intend to present the characteristics of Hachiro-Gata Clay and some investigations observed during the construction of test dikes, including dike failure test performed on them.

View full abstract

This paper presents the relation between the modulus of rupture and the unconfined compressive strength. To obtain this relation, the undisturbed and disturbed soil samples have been used. The test for modulus of rupture is very simple and the necessary amount of sample is not so much, and the reliance of this test is the same as the unconfined compression test.

View full abstract

By taking as sample Osaka alluvial clay the author studied the sensitivity of clay. As the result, we could comprehend that the behaviour of the "special water in clay" is essential to the problems of sensitivity.

View full abstract