Geoelectrical Investigation of Subsurface Heterogeneity and Influence of Roots on Infrastructural Planning

Abstract

Tree roots pose risks to buildings and roads by applying pressure to foundations and pavements, causing structural defects and instability. Their growth can modify soil composition, impacting stability and drainage. Effective planning and management are vital to addressing these issues in construction projects. At the University of Benin, Faculty of Education open field, a geoelectric survey was conducted to assess tree root spread. Using Electrical Resistivity Imaging (ERI) with a Wenner-Schlumberger array, six traverses formed a 3D model, processed using RES3DINV software, and visualised in Voxler. The 3D model showed a distinct top layer, with resistivity values ranging from 895.00Ωm to 1549.00Ωm at a depth of approximately 8.20m. Notably, resistivity values exhibit spatial heterogeneity, influenced by both anthropogenic activities and natural features such as trees. Elevated resistivity zones between 10.00m and 187.00m are attributed to human activity, while variations along the horizontal axis are associated with the presence of tree roots. Our findings underscore the significance of integrating geophysical methods for detecting tree roots, which is essential for infrastructure planning and management.