6.1 Consolidation behavior of soil

 

At the 1 G field, consolidation behaviour of soft clay is not predicted by means of so called H2 law because of self weight of the soil. While H2 law is applicable in the centrifugal field. In Table 1, similarity rule between prototype and models are shown. In Osaka City University, modelling of models on the self weight consolidation was performed, in which clay specimen of 10 cm, 5 cm and 2.5 cm were prepared in oedometers shown in Fig. 1, and put into centrifugal acceleration fields of 50 G, 100 G and 150 G, respectively. Curves for consolidation ratio and settlement were obtained through the tests (Fig. 2) and found to be almost identical to each other. Variation of consolidation ratios and settlement with time in prototype scale were obtained in the tests as shown in Fig. 2. It was found that these models under the same drainage conditions (double or single) showed a unique variation respectively.

 

Table 1 Similarity of centrifugal model and prototype

Centrifugal model

Prototype

centrifugal acceleration (G)

50

100

200

1

height of clay (cm)

10

5

2.5

500

scale

1/50

1/100

1/200

1

consolidation time

1/(50)2

1/(100)2

1/(200)2

1

settlement

1/50

1/100

1/200

1

Fig. 1 Two types of transparent oedometer used in centrifugal acceleration field

 

Fig. 2 Consolidation ratio and settlement in prototype scale

 

Reference

Mikasa, M. and Takada, N. (1973) : Significance of centrifuge model test in soil mechanics, Proc. of 8th ICSMFE, Vol. 1, pp. 273-278.