Evaluation of CPT - based Correlation of Fines Content and Soil Behaviour Index for Groningen Soils

Abstract

Earthquakes in the past few decades has questioned the safety of people and infrastructure in Groningen region and its surroundings areas. The excessive gas extraction from the subsurface has led to human-induced earthquakes in this region. Liquefaction is a phenomenon that occurs as a result of earthquakes, reducing the soil shear strength to zero and the soil in turn behaving like a liquid. It has been observed in other parts of the world in case of natural and human-induced earthquakes alike. Thus, it is necessary to identify the liquefaction prone regions and taking steps towards creating better designs, equipped to handle earthquake loads along with precautionary measures, to save existing building and infrastructure. In order to do so, it is important to examine the existing the methods, various parameters and factors that influence the liquefaction potential analysis. In this project, the different factors that could influence Liquefaction Potential Analysis are studied based on the existing CPT-based correlations between Fines Content (FC) and Soil Behavior Index(IC). The previously proposed correlation by Boulanger and Idriss (2014) is examined for Groningen Soils to evaluate if it needs any modifications. Depth of the sample, Distance between CPT and borehole, Grain Size Distribution and Geology of the sample are main factors considered for the study. Each of these factors are analysed by collecting laboratory samples of Grain size analysis test from Groningen region. The strength of the correlation between FC and IC is evaluated based on the factors. This study would be beneficial for geo-technical software developers, construction and design engineers who highly depend on correlations and it gives insight of how different the onsite scenario can be from the predicted values using correlations. It contributes to the future research on creating a data base of the all samples in the Netherlands, to indicate high risk regions. It also helps in answering if IC is a good parameter to consider while evaluating liquefaction potential for Groningen Soils.