10. Why is the leap of faith gone from second limit equilibrium model to closure? [LV-P]
Given the nature of the site, several limitations were imposed on the investigation. Limited access to the site was primarily due to constraints posed by dense vegetation and steeply sloping ground. Works were only carried out where safe access and working areas could be achieved. Vegetation clearance was undertaken to gain access to previously inaccessible areas however, a large proportion of the study area remains covered with vegetation and limited, to no investigation was undertaken in these areas.
Several investigation options were reviewed taking into consideration many factors including but not limited to, Health and Safety, the effectiveness of the method and cost. Intrusive investigation could only be undertaken in areas of cleared vegetation and where it was safe to do so. Geophysical survey was implemented to supplement the Ground Model.
Assessments have been undertaken on the available information considering the site constraints. Modelling has been careful to acknowledge uncertainties linked to the constraints.
The Ground Model, material parameters and groundwater conditions have primarily been determined from the investigation and geophysical findings, along with established correlations. These and other assumptions for the stability models are listed.
Considering the reduced availability of information on ground parameters, the values used in the model were adopted from a combination of in-situ testing and laboratory testing or established correlations from other soil characteristics and information to specific materials is discussed. We considered that this approach provided a realistic indication of the soil and water conditions at the site; a requirement for further evidence was identified.