Discussion on “Ultimate Bearing Capacity of Rock Masses under Square and Rectangular Footings”

Abstract

This discussion is based on the original paper by Mansouri et al. (2019) (hereafter the authors of the original paper). The original paper presents an interesting study dealing with the determination of the bearing capacity of rock masses under square and rectangular footing resting on the ground surface. The bearing capacity is evaluated using a commercial finite element code PLAXIS 3D with the built-in Hoek-Brown constitutive model.

The authors use the load-settlement curve obtained from numerical analyses to report the bearing capacity coefficient Nσ (Table 5 of the original paper). The original paper states various methods such as tangent intersection, log-log, hyperbolic, and 0.1B for the determination of the bearing capacity from the load-settlement curve. The authors claim to employ each of the methods and report the least value as the bearing capacity. As examples, the authors provide two load-settlement curves (Fig. 2 and Fig. 3 of the original paper) and highlight the determination of the ultimate bearing capacity based on the 0.1B method and the tangent intersection method.

In this discussion, the discusser presents the concerns related to the calculation and reporting of the bearing capacity using the 0.1B method where the bearing capacity should be reported corresponding to a settlement of 10 percent of the footing width. The concerns are discussed below.