GIS-Based Mapping of Geotechnical and Geophysical Properties of Lahore Soils

The spatial distribution of geotechnical and geophysical properties of soil delineates the subsurface soil type and condition necessary to ensure structural safety and serviceability, detailed investigations for engineering projects, and the foundation design under static and seismic loading conditions. This study presents the spatial distribution of soil type, standard penetration test (SPT) N values, bearing capacity, groundwater depth, and shear wave velocity using the database from sixty-five boreholes in GIS (geographical information system) software. The data were processed and interpreted through geostatistical contouring techniques (e.g., kriging and inverse distance weightage). The cross-plots were generated further to facilitate the interpretation of contour maps at unsampled locations. A correlation was established between measured and estimated shear wave velocity and standard penetration test N-values for the study area. It was then tested against the literature-based correlations to enhance the reliability of predicted geotechnical properties. A correlation coefficient of 0.77 between measured and predicted SPT N values improves the reliability of estimated properties (e.g., bearing capacity, shear wave velocity) at unsampled locations. The SPT N values, shear wave velocity, and allowable bearing capacity seem to be interdependent and varied with soil type and may be used for soil characterization and shallow foundation design at undrilled locations. The geotechnical maps generated in this study for Lahore city are novel and consistent with the soil types of the study area. Geotechnical engineers can use these maps for preparing geotechnical reports for the study area.