Estimation of vertical subgrade reaction modulus for sands from CPT investigations

摘要

A method for the rapid estimation of the subgrade reaction coefficient k for sands was introduced in 2013 (Barounis et al.) from CPT data. In this paper the method is applied for a building site in Christchurch, New Zealand that suffered structural damage from the recent Canterbury earthquakes. The method is relying on q_c measured and a value for k from CPT (K_(CPT)) is obtained. This value is further corrected for size effects and after the use of a back calculated factor of safety, the value corresponding for a given foundation shape and depth is estimated. The results correlate sufficiently with published values for foundations on loose to medium dense sands.