A New Technique for Reduction of Excess Pore Pressure during Pile Driving: Discussion

The authors are to be complimented on an interesting case history presenting an original method of solving the commonly occurring problem of development of excess pore pressures, when driving piles in soft clays. In Fig. 5, the authors present the measured pore pressures and number of piles driven on specific days. This figure indicates that the developed pore pressures were considerably smaller after the installation of the Geodrain on the piles, as compared with the measurements before the drain application. However, as the magnitude of the measured pore pressures is less dependent on the number of piles driven per day and more on the distance from the piles to the piezometers, a different plotting of the results gives a better basis for the conclusions drawn by the authors. In Fig. 1, the writer has plotted £or each driven pile the distance against time to two piezometers, numbers P-1 and P-3. A black dot shows the distance (and date) of a pile relative to piezometer number P-1 and an open dot that of the same pile relative to piezometer number P-3. The lower diagram in Fig. 1 shows the piezometric elevations measured in piezometer numbers P-1 and P-3. A study of the measurements taken before