Abstract:
This paper presents the study on pore water pressure distribution during construction of cement column in the EGATs reservoir construction at Wang Noi power plant. The 80 cement columns, which are 50 cm in diameter and 9 m in length, were constructed with grouting pressure of 250 bar as the foundation of embankment. Open standpipe piezometers were installed in order to measure initial pore pressure at the depth of 3, 6 and 8 m. And closed hydraulic system piezometers were installed 8 positions at the depth of 3, 6 and 8 m in each position, in order to measure excess pore pressure which occurred during the construction of cement column and after the construction of cement column.From the experiment, it is found that the average of initial pore pressure at the depth of 3, 6 and 8 m are 0.175, 0.428 and 0.678 ksc, respectively. The maximum excess pore pressure which could be measured during the construction of cement column period at the depth of 3, 6 and 8 m are 0.261, 0.528 and 0.62 ksc, respectively. The average value of the excess pore pressure at 66 days after the completion of construction of cement column at the depth of 3, 6 and 8 m are 0.00, 0.02 and 0.067 ksc, respectively.