Estimating Shear Strength Properties of the Surrounding Soils Based on the Execution Energies of Piles

Abstract

Historically, empirical relations are the basis of everyday foundation design. These relations, however, rely on specific datasets, which may not represent the true conditions observed in the field. Even in situ tests rely on empirical correlation formulas, which link observed phenomena to soil properties. These correlations should be updated according to the specific design conditions. Big data (BD) workflows enable the use of massive data available to update the correlations and to provide more accurate predictions of the parameters studied. Thus, in this paper, a BD approach is used to study the relation between the drilling process of continuous flight auger piles and the shear strength properties (SSPs) of the surrounding soils. Soil surveys were carried out to identify the soil strata in the site and to validate the estimates of the SSPs. The results show that indirect measurements are in accordance with typical undrained shear strength and friction angles of the materials considered.

An Energy-Based Big Data Framework to Estimate the Young’s Moduli of the Soils Drilled during the Execution of Continuous Flight Auger Piles

“…By applying a sufficient torque, the drilling helix will be introduced into the ground, surpassing the drilling resistance of the soil. Literature indicates that there is a relationship between the overall energy expenditure in the drilling process and the resistance of the soil [6,9,10].…”

“…In the case of the execution of CFAPs, torque is applied by means of the rotary table located at the top of the auger, mentioned and illustrated in Figure 1, resulting in a certain speed of penetration and rotation of the auger. Of the parameters obtained during the executive process, the torque presents correlations with the shear force and the load capacity of the soil [9,10].…”

“…Strength parameters can be estimated from drilling data by both theoretical and experimental approaches [10]. These approaches, on the other hand, are common in engineering practice but uncommon in BDA, as they are connected to the physical modeling of the phenomena themselves.…”

“…Besides the penetration rate, the literature reveals that the energy required for drilling a given volume of material can also be correlated to strength and deformability parameters of the drilled materials [1]. Ozelim et al [18], for example, used literature data to build simple regression models to estimate the unconfined compressive strength of the excavated soil layers based on the execution energy of CFAPs. Ozelim et al [10], on the other hand, estimated shear strength properties of the drilled based on such execution energy.…”

“…Ozelim et al [18], for example, used literature data to build simple regression models to estimate the unconfined compressive strength of the excavated soil layers based on the execution energy of CFAPs. Ozelim et al [10], on the other hand, estimated shear strength properties of the drilled based on such execution energy.…”