Analysis of the increase in vertical soil stresses at different depths caused by building loads

Abstract

Within soil mass, stress generated by the self-weight of the terrain and external loads can affect underground structures such as channels, tunnels, and pipelines. In recent years, the main campus of the Technical University of Manabí, located in Portoviejo, Ecuador, has undergone significant infrastructure expansion, resulting in increased soil pressures that may compromise structural integrity. This study aims to analyze, quantify, and compare the vertical stresses induced in the soil beneath the Faculty of Humanistic and Social Sciences building using two methods: Boussinesq’s equation for rectangular foundations and Newmark’s Influence Chart applicable to any foundation geometry. The building’s foundation consists of continuous footings in two directions, which required adaptation to the rectangular form assumed in Boussinesq’s model. Architectural and structural plans were used to calculate the loads transmitted to the foundation. Vertical stresses were determined at 1-meter intervals from 1 m to 15 m depth. The maximum vertical stress, according to Boussinesq, occurred at 2 meters, whereas Newmark’s method indicated a peak at 1 meter. The comparative analysis revealed a maximum stress difference of 46.21%. This evaluation of vertical stress transmission enables the prediction of potential impacts from structural and adjacent loads on future underground works within the university campus.