Modelling the spatial variability of Standard Penetration Test data for Chennai City using kriging and product-sum model

Modelling the spatial variability of soil properties is very much essential in establishing the engineering parameters for the design and construction of geotechnical structures and facilities. The Standard Penetration Test (SPT) 'N' value of a location is widely used to determine the engineering properties of the soils through empirical correlations. In this study, a 3D site characterisation model is developed using ordinary and simple kriging with an objective of evaluating the spatial variability of corrected SPT 'N' (N-corrected) values in the subsurface of Chennai City. The alternative kriging approach using product-sum covariance model is implemented to model the SPT N-corrected values in an anisotropic environment. The estimated SPT N-corrected values are compared with the actual borehole data at selected locations. It is noted that the ordinary kriging has given more accurate estimates closer to the actual SPT N-corrected values than the simple kriging. The estimated SPT N-corrected values in the 3D subsurface environment will help in better interpretation of the subsurface information, making informed decisions with regard to future developmental activities and effective management of the urban centres of the Chennai City.

Automated summary

In this study, a 3D site characterisation model is developed to evaluate the spatial variability of corrected SPT 'N' values in the subsurface of Chennai City. It is found that the ordinary kriging method provides more accurate estimates compared to the simple kriging method. The estimated values can help in interpreting subsurface information and making informed decisions for future development and management of Chennai City.