Abstract The offshore industry has been challenged with the necessity to build structures with foundations on carbonate soils, found in extensive areas of the tropical and intertropical zones of the planet. As a better understanding of the behavior of these soils becomes more and more indispensable, this paper presents equations to predict the dynamic behavior of carbonate sands, in which two expressions (G/Gmax versus γ and D versus γ) were obtained via multiple linear regression using data from resonant column tests carried out on carbonate sands from Cabo Rojo, Puerto Rico (Cataño & Pando, 2010). The proposed equations agreed well with experimental data. The error for the expressions G/Gmax versus γ was less than 10%, while the expressions D versus γ trended to underestimate the values for the loose condition (Dr = 24%), presenting an effective confining stress of 50kPa. Furthermore, the proposed equations were compared with predictions exhibited by Javdanian & Jafarian (2018) of G/Gmax versus γ and D versus γ for carbonate sands, also yielding fairly concordant results.

Abstract This article presents a series of propositions for the prediction of horizontal displacements for continuous fight auger piles in granular soil profiles through modifying the parameters Ay and By from the method proposed by Matlock and Reese (1961). Empirical proposals were also presented for calculating the horizontal soil reaction coefficient (nh) for granular soils. Data from ten horizontal static load tests, conducted in the city of Paulino Neves (State of Maranhão, Brazil) were used to develop and validate the propositions. The data regarding results of nine static load tests (PCH 1 to PCH 9) were used to develop the propositions, whereas results for PCH 10 and other data from other studies (Cases A and B) were used in the validation step. Modifying the parameters used in Matlock and Reese’s method resulted in convergent and coherent predictions for all the propositions assessed in this study. In addition, predictions made for piles used in the validation phase yielded results very congruent with experimental displacements.

Resumen El control ejecutivo generalmente se realiza mediante pruebas de carga estática, un método costoso y que requiere mucho tiempo. Se realizaron ensayos de carga estática en ocho pilotes controlados con el objetivo de evaluar la carga última. Este estudio sugiere un enfoque innovador y no destructivo para validar el rendimiento del campo de pilotes de raíces, utilizando un velocímetro digital conectado al cabezal giratorio del equipo de perforación. El método propuesto monitorea las variables relacionadas con la capacidad portante durante la instalación del pilote y propone una ecuación empírica para estimar la capacidad portante última de los pilotes raíz. Para los pilotes evaluados, las predicciones obtenidas con las ecuaciones propuestas coincidieron, así como con los resultados de las pruebas de carga estática, lo que la demuestra como una opción factible y útil para el control ejecutivo de pilotes de raíz, especialmente cuando no se dispone de pruebas de carga.

Abstract Root piles are injected and installed during mortar shaft construction, using pressures of up to 500 kPa. The executive control is typically done through static load testing, an expensive and time-consuming method. Static load tests on eight controlled piles (diameters between 310 mm and 410 mm) were performed, aiming at evaluating pile ultimate load. This study suggests an innovative, non-destructive approach to validate root pile field performance, using a digital speedometer connected to the drilling rig's rotating head. The proposed method monitors variables related to bearing capacity during pile installation and proposes an empirical equation to estimate the ultimate bearing capacity of root piles. For the assessed piles, the predictions obtained with the proposed equations agreed fairly well with results from static load tests, proving it as a feasible and helpful option for the executive control of root piles, especially when load tests are not available.

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 When designing a foundation project, it is necessary to ensure that all the elements meet both ultimate and serviceability limit states, which call for predictions of settlement and load capacity. The load transfer methods are a widely used alternative to estimate the load-settlement ratio of piles in the design of foundation projects. However, traditional load transfer methods do not consider the interactive effects between the elements in pile groups. This study proposes changes to the load transfer curves developed by Bohn et al. (2016), aiming to incorporate the group effect in the analysis of load-settlement relationships in pile groups. Comparisons between the predicted settlements obtained using the proposed method and the results of load tests performed by Dai et al. (2012) in Jiangsu, China, showed that the modifications proposed in this study agreed well with the experimental results for most of the analyzed groups.