An improvement in the determination of end bearing capacity of drilled shafts in sand

There are many equations available in the literature using the results of CPT (cone penetration test) and SPT (standard penetration test) measurements to predict the end bearing capacity of drilled shafts in sand. However, there are few equations that use soil parameters, such as friction angle and elastic modulus, as input values. Also, these available equations usually overestimate the end bearing capacity, and at times show conflicting results with respect to the parameters they use. This paper describes a numerical procedure to overcome the above shortcomings. The results obtained in this study were compared with both experimental and numerical results available in the literature. A series of analyses is also conducted to assess the effects of various soil and pile parameters on the magnitude of end bearing capacity of piles embedded in sand. These parameters include diameter and length of pile, friction angle, and Poisson's ratio of soil. Based on the numerical analyses carried out in this study, a new equation is proposed to estimate the end bearing capacity of drilled shafts in sands. The results of the proposed equation are also compared with experimental data available in the literature on end bearing capacity of drilled shafts. The comparison shows better agreement of the suggested end bearing capacity equation with respect to other previously proposed methods. © 2019 Taiwan Geotechnical Society.