Selection of standard penetration test number for geotechnical investigation of a vertical cross section considering spatial variability and correlation in soil properties

Abstract

Standard Penetration test (SPT) is a widely used in-situ test for characterizing variation of subsurface soil properties, and results of site investigation are usually simplified as a 2D vertical cross-section for subsequent geotechnical design and construction. Current geotechnical design codes and guidelines only provide general recommendations for selection of an appropriate number of in-situ tests (e.g., SPT) (e.g., the greater variability of subsurface conditions, the larger number of SPTs required to obtain sufficient underground information). No quantitative or rational method is available for selecting the appropriate number of SPTs considering spatial variability and correlation in subsurface conditions. A comprehensive parametric study is carried out in this study to investigate the influence of spatial variability in subsurface conditions on the minimum SPT number needed for satisfying an accuracy requirement of site investigation. Random field is adopted to model spatial variation and correlation in soil properties in typical site conditions, and 2D Bayesian compressive sampling is used to interpolate sparse SPT data. Based on the parametric study results, a statistical chart is developed for geotechnical engineers to conveniently select appropriate number of SPTs in a vertical cross-section. Real SPT data from New Zealand are used to illustrate and validate the proposed method.

Geotechnical investigation measures and techniques in construction engineering based on multi-source data fusion

“…Literature [13] proposes that resistivity tomography has been combined with geotechnical techniques, which is very helpful in the preliminary investigation of strong foundation design for building construction sites, and that the analysis of four cone penetration data, including geophysical and geotechnical methods, helps to guide the selection of pile-type foundations instead of shallow-type foundations. Literature [14] proposes the standard penetration test as a widely used field test method to characterize the variation of subsurface soil properties in order to investigate the effect of the minimum number of SPTs required for accuracy, the spatial variability and correlation of the soil properties were modeled through a comprehensive parametric study and statistical plots were created based on the results of the study. Literature [15] proposes a laser scanner deployment for drilling holes in abandoned coal mine workings by acquiring data to create models of voids and caves left behind, thus verifying that terrestrial laser scanners have changed the mapping of rock exposures in surface and subsurface environments, and are an ideal tool for exploring ancient abandoned subsurface spaces.…”

Multichannel Analysis of Surface Waves (MASW) to Estimate the Shear Wave Velocity for Engineering Characterization of Soils at Hawassa Town, Southern Ethiopia

“…Due to its simplicity, the standard penetration test (SPT) is the most widely used dynamic in-situ test in geotechnical site investigation for describing the dynamic properties of a soil in foundation stability analysis [21]. Many researchers have used SPT-N values to identify the stiffness of a soil, depth of groundwater table, soil profile/type, site class, and relative density as these are very important to assure the suitability of a site for a building foundation [22][23][24].…”