Stabilization Methodology in Foundation Soils by ERT-3D Application in Estepona, South Spain

Alfonso Gutiérrez-Martín,José I Yenes,Marta Fernández-Hernández,Ricardo Castedo

doi:10.3390/app11104455

Abstract

The paper proposes a novel methodology for the stabilization of shallow foundations, with a simplified model combined with 3D electrical resistivity tomography (ERT-3D and consolidation injections. To determine its usefulness, the method has been applied in a case located in Estepona (southern Spain). The chosen tomography model is the dipole–dipole configuration, with an optimized distance between electrodes of 0.80 m for a better visualization of the foundation subsoil; with this parameterization, a total of 72 electrodes were installed in the analyzed case. In this work, the depth of the anomaly in the building’s supporting subsoil was detected ranging from 2.00 m to 3.90 m deep. The study also delineates areas of high resistivity variations (50–1000 Ω m) in the middle and eastern end of the field. These data have been validated and corroborated with a field campaign. The results of the ERT-3D monitoring are presented, once the investment data has been processed with the RES3DINV software, from the beginning to the end of the stabilization intervention. The novelty occurs with the interaction between the tomography and the foundation consolidation injections, until the final stabilization. This is a very useful methodology in case of emergency consolidation, where there is a need to minimize damage to the building. Thus, people using this combined system will be able to practically solve the initial anomalies of the subsoil that caused the damages, in a non-invasive way, considerably lowering the value of the resistivities.

Highlights

The success of architectural structures, which are built directly on the earth’s surface, depends, among other factors, on the support offered by the foundation materials bearing the structures’ loads [1,2,3,4,5,6] In turn, the ability of a building’s foundation to offer the necessary support for architectural structures depends on the bearing capacity of the soils underneath, and, if the upper layer has heterogeneous physical properties, it could cause spatial variability in the foundation material’s strength
The results of our model show an uncertainty in its acceptable magnitude
It is necessary to interpret the characteristics of the subsurface soil/rock in an electrical resistivity tomography methodology

Summary

Introduction

The success of architectural structures, which are built directly on the earth’s surface, depends, among other factors, on the support offered by the foundation materials bearing the structures’ loads [1,2,3,4,5,6] In turn, the ability of a building’s foundation to offer the necessary support for architectural structures depends on the bearing capacity of the soils underneath, and, if the upper layer has heterogeneous physical properties, it could cause spatial variability in the foundation material’s strength. It is common to find many stress-induced cracks and other defect-related issues due to the various structures and foundations of historic, public, and private buildings, and some of these problems are disasters in the making [12,13,14]. This necessitates proposing a non-invasive intervention methodology for the subsoil of these buildings to avoid collapse

Methods

Results

Conclusion