Abstract A root pile is a form of injection pile (cast-in-place with pressure, with very distinct construction aspects from the known micropile type). During the mortar shaft development, these piles are inserted using distinct injection pressures of up to 500 kPa. Static load tests are typically used to control root piles, which can be an expensive and time-consuming testing procedure. Static load tests were performed on eight monitored piles with diameters of 350 and 410 mm to investigate root pile performance control during pile installation. This research presents a refined and developed alternative methodology for confirming root pile performance using a digital odometer attached to the drill rig's rotatory head. The methodology consists of monitoring variables obtained during pile installation related to pile bearing capacity. Moreover, empirical equations with simple and relevant applications to estimate root pile bearing capacity during installation are proposed. The developed equations produced results consistent with the values obtained from static load testing on the test piles. Therefore, the results suggest that the proposed methodology is a viable alternative for root pile performance control.

Abstract The use of geosynthetic reinforcement in piled embankments over soft soils is an effective solution for the reduction of settlements and to increase the embankment stability. The most efficient position for the reinforcement layer is on the pile cap or head. However, a direct contact of the reinforcement with sharp edges may damage it, compromising its efficiency to transfer loads to the piles. This paper investigates the possibility of mechanical damages in geosynthetic reinforcements on pile caps by large scale laboratory tests. Tests with and without pieces of nonwoven geotextile protective layer between the caps and the reinforcements were executed. Wide strip tensile tests were performed on exhumed reinforcement specimens after the tests to assess tensile strength and stiffness variations. A statistical analysis of the results shows reductions in tensile strength of unprotected reinforcement layers of up to 28%. A mechanical damage index is introduced and its correlation with calculated reduction factors is investigated. The use of a piece of a thick geotextile layer to protect the reinforcement against mechanical damage can be effective. However, the geotextile product must be properly specified and installed with due care.