Proceedings - Seventh International Conference & Exhibition on Piling and Deep Foundations, 1998, Vienna, Austria, (DFI)
The bearing capacity of driven steel piles in weathered chalks
M. Bustamante, L. Gianeselli, L. Weber
The mechanical properties of chalks differ strongly from conventional rocks such as granite, marl and sandstone. Indeed, the entry of a pile pulverizes the chalk and breaks down its cellular structure. In presence of ground water, this powdered rock forms a slurry which lubricates the surfaces of the pile shaft. As a result, piles can be driven deeply into moderately to highly weathered chalks below water table without any marked increase in driving resistance. Some authors also state that the shaft resistance in chalks increases substantially with time after driving; the test presented here does not allow concluding to such a phenomenon. Within this presentation, the results of loading tests, performed in France and Belgium over the last few years on 5 job sites, will be analyzed in order to deduce helpful design parameters of the unit shaft resistance and unit toe resistance of driven steel piles in weathered chalks.
|article #356; publication #34 (IC-1998)|