A total of four activities are de ned:

A3.1 Probabilistic assessment of penetration resistance of abucket foundationIn 2014 and 2015 GRAM A3.1 combined achievable penetration depth with failure probability ofsuction installed caissons in sand addressing the following question: What adjustment factorshould be used to achieve the same probability of failure if the relative density changes?

The work in 2016 will include developing a method for combining failure probability and forinstallation and capacity design, use installation information to update the failure probability ofthe as installed caisson capacity, use installation information to update the foundationsti ness.

A3.2 TBT concentration in the Drammen ordThe research in 2014 and 2015 included developing methods of probabilistic analyzes ofenvironmental problems with a focus on the following questions: What is the probability thatthe TBT concentration will fall under EQS- limit within an X number of years? A probabilistic

Prosjekt | DP3 - Probabilistic vs. deterministicmethod

PERIODE | 2014 - 2016

PROSJEKTLEDER | BJØRN

KALSNES

The aim of GRAM subproject DP3 is to focus onapplications of probabilistic risk/reliability analysis ingeotechnical problems, one in each major market areaof NGI.

approach of the hazard was also included. The case of natural decrease of TBT concentrationin the Drammen ord was investigated as a test case.

In 2016 a methodology to communicate the results of a probabilistic approach will bedeveloped.

A3.3 Excavation - Uncertainty related to characteristic shearstrengthThe case study chosen for land foundations was related to the interpretation of undrainedshear strength pro le for an excavation problem. For this exercise, a location south of Oslo,near Lysaker, where large amount of samples were taken and special laboratory tests werecarried out, was chosen. The available data were sent to a number of geotechnical engineers inNGI-Oslo and NGI-Trondheim, both in onshore and o shore divisions. Additionallyanonymous data were sent to an "expert-panel" (a NIFS project including Vidar Gjelsvik fromNGI), which is working on making guidelines on how to choose a design su-pro le fromdi erent data sources.

The available data are also being processed statistically to derive the best estimate andstandard deviation of the undrained shear strength pro le. One of the main lessons from thisexercise is compare the characteristic pro le(s) developed by the "experts" with the calculatedmean values and standard deviations. The results will be used to do a probabilistic design for asheet pile wall at the excavation location.

A3.4 Probabilistic assessment for a quick clay slideThe example application chosen for natural hazards (landslide) was to assess the impact ofuncertainties in shear strength parameters on the reliability of the performance prediction for aquick clay slope. A multivariate normal model among undrained shear strength, liquidity index,sensitivity and overconsolidation ratio of sensitive clays was developed. This model can reducethe uncertainty (COV) in undrained shear strength e ectively using a Bayesian framework.

Farrokh NadimPOSITION | Technical DirectorRiSC – Risk, Slope stability andClimate adaptationE | farrokh.nadim@ngi.noM | +47 975 49 957

Hendrik SturmPOSITION | Technical Lead OffshoreRenewablesComputational Geomechanics (CGM)E | hendrik.sturm@ngi.noM | +47 951 41 138

Gijs BreedveldPOSITION | Technical DirectorEnvironmental EngineeringE | gijs.breedveld@ngi.noM | +47 932 22 345

Zhongqiang LiuPOSITION | Project engineer IRiSC – Risk, Slope stability andClimate adaptationE | zhongqiang.liu@ngi.noM | +47 479 29 799

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