| Abstract | Soft Bangkok clay can be divided into two layers. The weathered layer behaves as an over consolidated clay while the non-weathered layer possesses something close to a normally of slightly over-consolidated soil.
The liquidity index increases to about 1.0 from the ground surface to the non-weathered layer and decreases with increasing depth to the bottom of the noon-weathered layer. Therefor, the shear strength holds the same figure as the liquidity index with average value frm 1.0 to 2.4 t/sq. m. in the non-weathered layer. The effectives angles of shearing resistance, , are found to be approximately 21.3 at AIT compus, 23.9 at Nong Ngoo Hao, 28.6 at Pathum Wan and 24.9 at Pom Prachul.
As a recent marine deposit, Bangkok clay possesses quite high compressibility characteristics. The initial void ratio, eo, varies from 1.68 at Pathum Wan to 2.99 at Nong Ngoo Hao and the compression index, Cc, varies from 0.78 to 1.42 at the same sites. For the over-consolidation ration of the soft layer, just as most of the marine deposits, 1.6 to 1.8 is the range.
Since Bangkok clay is a homogeneous deposit, the values of Ko are very close at each site and 0.61 can be served as a representative value. The permeability in horizontal direction in the weathered layer is in the order of 10_5 by field and 10_7 by lab. measurements, while in the non-weathered layer, it is in the order of 10_8. The permeability in the vertical direction is found to be half that of the horizontal. For the pore pressure coefficient at failure, Af, it varies from 0.2 to 1.0, except in Pom Prachul which has a range of 0.79 to 1.58. |