Determination of pile capacity of instrumented pre-cast concrete piles in an unsaturated Brazilian soil using CPT and SPT-T tests

摘要

An assessment of the pile capacity for pre-cast concrete piles via Cone Penetration Test (CPT) and Standard Penetration Test with Torque measurement (SPT-T) is presented in this paper. Two pre-cast concrete piles, instrumented along the shaft with strain-gages, were built in a Brazilian tropical soil found at the experimental test site at Unicamp (State University of Campinas), Sao Paulo, Brazil. The soil profile and properties were carefully characterized: they are composed of 6 m thick porous clay on top of a residual soil classified as clayey silt. Several electrical CPT and SPT-T tests were carried out in order to use the resulting data to estimate the capacity of the piles using existing methods. Compression and uplift and pile load tests results were also available, which provided a comparison between measured and estimated values of pile capacity. Comparisons were made between tip and shaft resistance obtained by means of load tests and the CPT and SPT-T-based methods.