A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Constant rate of strain consolidation tests with radial drainage condition were conducted to investigate the horizontal consolidation behavior of soft Bangkok clay with emphasis on the strain rate effect. The drainage path is varied to investigate the effect of pore water pressure distribution across the sample. Sixteen (16) CRS tests with 1 cm diameter of center drain were conducted at various strain rates to compare with nine (9) CRS tests with 2 cm diameter of center drain. The pore water pressure distribution across the sample in the CRS tests were measured at two locations. The results show that the pore pressure distribution curves obtained at slow strain rates match well with those obtained from theoretical solution based on Barron's theory. The horizontal coefficients of consolidation and permeability in over-consolidated range are much higher than that in normally consolidated range with abrupt change occurred close to the preconsolidation pressure. The results show that the horizontal coefficients of consolidation and permeability are independent of the strain rate. The results indicated that there is an increase in apparent preconsolidation pressure with increasing strain rate, therefore it was concluded that some secondary compression had occurred during primary consolidation for soft Bangkok clay. In addition, the preconsolidation pressures obtained from 1 cm and 2 cm center drain CRS tests agree well. However, the horizontal coefficients of permeability and consolidation obtained from 1 cm center drain CRS tests are higher slightly than those obtained from 2 cm center drain CRS tests by about 1 to 2 times.

Thesis (M.Eng.) - Asian Institute of Technology 2000