For certain geotechnical structures, such as dikes and levees, the design quality is heavily reliant on the sampling quality. In addition, the extent of consequences on geotechnical design of using parameters from samples with a certain degree of disturbance in laboratory tests is unclear. While the available literature has been mainly focussed on disturbance experienced by clay samples, the same empirical findings are not always applicable to organic soils such as peat and organic clay. The global objective of this thesis was to gain an understanding of sampling disturbance in organic soils using both established and non-destructive experimental methods. In order to achieve this, the traditional Dutch Ackerman sampling technique was compared to that of a recently developed sampler, the Deltares Large Diameter Sampler (DLDS). Non-destructive methods and 1D consolidation parameters were used to quantify disturbance in organic soil samples.

The results from existing databases showed that organic clay has a clear linear trend between w and RR and peat showed no definitive correlation, although the peat sampled by the DLDS had significantly higher water contents than the peats from the Ackerman sampler. Moreover, 37% of organic clay and peat Ackerman samples had an ∆e/e₀ below 7%. Meanwhile, all the DLDS results from the Deltares laboratory had an ∆e/e₀ of less than 4%. The use of this parameter is still questionable for peats, as the higher e0 found in DLDS peats is the cause for low disturbance measurements. However, the ∆e/e₀ index may be used in conjunction with other destructive and non-destructive disturbance parameters. Furthermore, the trend showed it becomes increasingly difficult to produce high quality samples with increasing in-situ vertical stress.

Using differences in shear wave velocity as a non-destructive disturbance determination technique, it was concluded that the increased shear wave velocity in Ackerman samples relative to the DLDS samples, although slight, was due to densification of the outermost volume of the sample being compressed by the sampling procedure. This effect was further observed in the other non-destructive method use in this investigation, CT scanning. Analysis of micro-CT scans showed that all specimens had higher greyvalue intensities at the perimeter than at the centre of the sample, however the observed effect was 7.4 times higher with the Ackerman specimens than with the DLDS specimens.

The main recommendation is to continue research on the effectiveness of using non-destructive methods to quantify sample disturbance in peats. For the sampling industry, it is advised to increase the diameter of the Ackerman sampling tubes to between 70 and 120 mm when sampling in peat. In addition, in light of the lesser disturbance caused by the DLDS, it is advised to deploy it in shallow peats instead of the Ackerman sampler with the current inner diameter of 67 mm. Furthermore, it is recommended to deploy both types of samplers side-by-side in sampling projects in order to diminish the effect of site-specific variables.

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.