New experiencies in the use of the Expander Body Technology
Mario Terceros A.1; MARIO A. TERCEROS H.1
1 INCOTEC SRL
Baixar PDF doi:10.20906/CPS/CB-04-0007
Resumo
The Expander Body (EB) technology has been used successfully to increase the pile toe capacity of bored piles in loose to medium dense soil. An important advantage of the EB system is the ability to monitor the EB expansion process, which provides important information regarding soil strength and soil stiffness. This information, obtained for each installed pile, can be used to determine the actual shape and pile toe area. The expansion pressure can be used to design the pile base capacity. The Expander Body system has been recently improved by incorporating the possibility of post-grouting of the soil below the expanded pile toe. This improvement measure provides additional strength and stiffness to the pile toe and reduces pile settlement. The shaft bearing capacity of the traditional bored piles can be increased significantly by using a soil displacement auger, which avoids soil decompression and increases lateral soil stress. This paper describes the principle of the EB system and its combination with the full displacement system for the shaft and presents new experiences in different soils. During the past 20 years, a large number of EB piles have been installed in Bolivia, Paraguay, Argentina, USA, Sweden, Japan and elsewhere, providing a sound database. Results from field loading tests are presented. A comprehensive study of test piles with and without EB base has been carried out which demonstrates the improvement effects that can be achieved by the EB pile system and the combination with the displacement auger pile method. A high degree of quality control can be achieved by monitoring the entire pile installation process, including the displacement pile and the Expander Body. For the case history included, a statistical analysis is presented in order to show how the EB system can be a very valuable tool for risk analysis because, after the installation of all the piles, a histogram of the resistance is obtained giving the possibility of better understanding about the soil heterogeneity, a very com
Palavras-chave: EXPANDER BODY; PRESSUREMETER; FULL DISPLACEMENT; QUALITY CONTROL