Vibro piles performance prediction using result of CPT

Vibro piles belong to the group of full displacement piles with an expanded base, characterised by a very high load capacity, especially in non-cohesive soils. The problem is to adopt a reliable method for the determination of full load–settlement (Q–s) curve. A frequent difficulty is the determination of the load capacity limit based on the static load test because the course of the load–settlement curve is of a linear nature. This publication presents the empirical method. It allows direct prediction of a full axially loaded pile settlement curve based on the values of q_c cone resistance obtained in cone penetration test (CPT). The advantage offered by this procedure is the accuracy of the obtained limit values in relation to the actual load-bearing capacity as compared to other methods based on soil parameters obtained in in situ testing. An additional advantage is the Q–s characteristics, which enable designing for intermediate values, allowing for the criterion of minimal or equal settlements. The shape of analytical curves was compared with static pile load test (SPLT) curves. This comparison showed large convergences between the analytical and measured curves.